KR20160145684A - Edge light-type backlight reflection film and backlight using same - Google Patents

Abstract

The present invention provides a reflective film for an edge light type backlight in which scratches are less likely to occur and a backlight using the same. The solution has a base film and a particle containing layer containing particles having a particle diameter of 25 to 50 占 퐉 and particles having a particle diameter of 1 to 15 占 퐉 and has the following requirements (i) to (iii) A reflective film for an edge light type backlight having a convex portion that satisfies the above-described conditions. (i) convex portions having a diameter of 25 to 50 mu m. (ii) the number of convex portions having diameters of 25 to 50 mu m is 10 to 100 per 0.64 mm < 2 > independently of the convex portions having diameters of 25 to 50 mu m. (iii) The number of convex portions included in the aggregate of the convex portions continuously contacting the convex portions having a diameter of 25 to 50 占 퐉 is 10 or less per 0.64 mm2.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a reflective film for an edge light type backlight and a backlight using the same,

The present invention relates to a reflective film for a backlight and a backlight using the same.

BACKGROUND ART In a liquid crystal display, a backlight illuminating a liquid crystal cell is used. Conventionally, depending on the type of liquid crystal display, a backlight of the edge light type is employed in a relatively small liquid crystal monitor, and a backlight of a direct lower type is adopted in a relatively large liquid crystal TV. BACKGROUND ART In recent years, the thinness of a liquid crystal TV has employed an edge light type backlight even in a large liquid crystal TV, and at the same time, the development of an edge light type backlight has been energetically performed. In addition, a light emitting diode (hereinafter abbreviated as an LED) is employed as a light source for lowering power consumption and mercury-free. As these reflective films for backlight, a porous white film formed by bubbles is generally used (for example, Patent Document 1).

In the backlight of the edge light type, a light guide plate is used as the optical member. 1, the light guide plate 2 and the reflection film 1 are generally disposed in contact with each other within the backlight, and the reflection film 1 passes through the light guide plate 2 and is irradiated to the reflection film side And has a function of reflecting light to improve the brightness of the backlight. Regarding the light guide plate, sizes of up to about 25 inches have been sufficient in conventional notebook computers and desktop monitors, and 30 to 60 inches are required in televisions. As a result, a plate containing a resin such as an acrylic resin, a resin obtained by mixing an acrylic resin and a styrenic resin, a styrenic resin, glass, or the like is used as a substrate and dot printing is performed thereon or molding is performed using a mold or a roll, A light guide plate 2 having a convex portion 5 as shown in Fig. 2 is being developed. The light guide plate 2 having a concave portion as shown in Fig. 3 has been developed by performing laser processing on the above-described substrate or by molding using a mold or a roll.

In the development of the above-described large-size and thin-type edge light type backlight, the following problems arise because the light guide plate and the reflective film are disposed in contact with each other, and this is a problem to be solved. That is, the problem that the light guide plate and the reflection film adhere unevenly to cause optical unevenness in the form of plane, line, and dot (in particular, a portion visibly brightened is referred to as white spot unevenness), and the light- There is a problem that optical unevenness is generated, and it has been a problem to improve these problems. As a reflective film technique for improving these problems, a reflective film having a convex portion of a specific height has been proposed (Patent Document 2).

Japanese Patent Application Laid-Open No. 8-262208 International Publication No. 2011/105294

In recent years, further advances in technology have caused various changes in display design and backlight design.

Particularly, in an edge light type backlight using an LED for a light source, an LED light bar is used. However, the position where the LED light bar is installed is conventionally arranged on four sides of the display, In order to reduce the cost and reduce the cost, the arrangement is changed to a long side 2 side, a short side 2 side, a long side 1 side and a short side 1 side.

With respect to the light guide plate, in order to reduce the resin amount of the light guide plate to reduce the cost and to reduce the thickness of the display, a thickness of 3 mm or more is conventionally thinner than 3 mm, for example, 2.5 mm or 2 mm Thinner than 1 mm, or less than 1 mm.

In addition to this, a plurality of optical films such as a diffusion film and a prism film have been used for the backlight. However, from the viewpoint of cost reduction and thinning of display, the number of optical films is reduced.

From the above design change, the performance required for the reflective film is higher.

For example, when the temperature inside the backlight rises due to the heat generated when the light source (for example, LED) is turned on, the light guide plate generally causes thermal deformation. Particularly in the edge light type, the temperature gradient inside the backlight tends to become larger at a portion apart from the portion near the LED light source, as the position of the light source changes. As a result of this temperature gradient, the degree of thermal expansion or the degree of heat shrinkage of the light guide plate is also varied depending on the portion, and as a result, a dimensional difference is generated in the light guide plate surface, and is easily deformed like a wave. The deformation of the light guide plate becomes more significant as the thickness of the light guide plate becomes smaller.

At this time, the reflective film in contact with the light guide plate contacts the light guide plate with almost uniform load in the surface if the light guide plate maintains planarity, and is inserted into the backlight. However, when the light guide plate is deformed, the light guide plate comes into contact with the backlight at a partly large load. At the position where the load pressed at this time is large, the light guide plate and the reflecting film are strongly struck, and the reflecting film is also prone to scratches. When scratches or stripe-like scratches are formed on the surface of the reflecting film itself, when light is incident on the reflecting film from the light guide plate, shadows are generated on the scratches of the reflecting film, The optical non-uniformity is visually recognized.

Such optical unevenness has been alleviated by the use of a plurality of optical sheets such as a diffusion film and a prism film which are generally used for a backlight. In the backlight design of recent years, since it is designed to reduce the number of optical films from the demand for cost reduction of backlight and thin display, it is difficult to reduce optical unevenness.

Therefore, there has been a demand for a reflective film which is improved in defects such as scratches on the concave shape and scratches on the stripe shape that are generated in the reflective film itself, but the conventional reflective film has not been sufficiently improved.

SUMMARY OF THE INVENTION In view of the problems of the prior art, the present invention aims to improve defects in the quality of a reflective film, such as scratches on the surface of a reflecting film and scratches in stripe shape, in the edge light type backlight reflecting film, And to provide a reflective film capable of improving the optical unevenness of the backlight by reducing the thickness of the backlight.

The present invention adopts any one of the following means in order to solve such a problem.

(1) A coating film comprising a base film and a particle-containing layer containing particles having a particle diameter of 25 to 50 탆 and particles having a particle diameter of 1 to 15 탆,

Wherein at least one surface satisfies the following requirements (i) to (iii).

 (i) convex portions having a diameter of 25 to 50 mu m.

 (ii) the number of convex portions having diameters of 25 to 50 mu m is 10 to 100 per 0.64 mm < 2 > independently of the convex portions having diameters of 25 to 50 mu m.

 (iii) The number of convex portions included in the aggregate of the convex portions continuously contacting the convex portions having a diameter of 25 to 50 占 퐉 is 10 or less per 0.64 mm2.

(2) A reflective film for edge light type backlight according to (1), wherein the face satisfying the requirements of (i) to (iii) is a face of the particle containing layer.

(3) The edge light type reflective film for backlight according to (1) or (2), wherein the SRz of the surface satisfying the requirements (i) to (iii) is 15 to 60 탆.

(4) An edge light type backlight using the edge light type back light reflecting film according to any one of (1) to (3).

According to the present invention, in the case of having a convex portion having a specific characteristic on at least one surface of the reflecting film, it is possible to improve the problem of defects of the reflecting film due to scratches on the surface of the reflecting film or scratches in the stripe pattern.

Thus, the reflection film obtained in the present invention can reduce optical unevenness when used in an edge light type backlight including an LED light source and a surface light source for illumination.

1 is a schematic diagram showing an embodiment of a large edge light type backlight using an LED as a light source.
2 is a schematic diagram showing the relationship between the light guide plate having convex portions, the reflective film and the back housing.
3 is a schematic diagram showing the relationship between the light guide plate having the concave portion, the reflective film, and the rear housing.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problem, that is, a reflective film capable of improving defects in the quality of a reflective film, such as scratches and stripe- In the case of having at least one convex portion on at least one side thereof

Hereinafter, the reflective film of the present invention will be described in detail. The reflective film of the present invention has a base film and a particle containing layer.

<Basic Structure of Reflective Film>

<< Base film >>

The base film is not particularly limited, and examples thereof include evaporated films of silver and aluminum, laminate films of silver foil and aluminum foil, white films, and multilayer laminated films. When the base film is used as a backlight for a liquid crystal display or a reflective film for lighting purposes, the reflectance of the visible ray should be high. As a result, a film containing bubbles and / or particles for emergency can be used. As the film, a thermoplastic resin film is preferably used. Although these thermoplastic resin films are not limited, a polyolefin-based or polyester-based film such as a porous non-stretched or biaxially-stretched polypropylene film or a porous non-stretched or stretched polyethylene terephthalate film is preferably used do. In particular, a polyester film is preferably used from the viewpoints of moldability and productivity.

Methods for producing these thermoplastic resin films are described in paragraphs [0034] to [0057] of JP-A 8-262208, paragraphs [0007] to [0018] of JP-A No. 2002-90515, 0008] to [0034] of Japanese Patent Application Laid-Open No. 2002-138150.

Among them, a porous biaxially stretched polyethylene terephthalate film disclosed in Japanese Patent Application Laid-Open No. 2002-90515 can be preferably used as a base film in the present invention for the reasons described above. Further, from the viewpoints of heat resistance and reflectance, a porous white biaxially oriented polyethylene terephthalate film obtained from a mixture of polyethylene terephthalate and polyethylene naphthalate, or a copolymer thereof, is preferable. In particular, a porous biaxially oriented polyethylene terephthalate film containing inorganic particles is preferable for improving the flame retardancy of the thermoplastic resin film itself. The inorganic particles are preferably 2 mass% or more, more preferably 7 mass% or more, further preferably 10 mass% or more, particularly preferably 30 mass% or more, based on the total mass of the thermoplastic resin film.

The constitution of the base film according to the present invention may be suitably selected depending on the intended use and the required properties, and is not particularly limited. Concretely, a single layer having at least one layer structure and two or more composite films can be exemplified, and it is preferable that at least one layer contains bubbles and / or inorganic particles.

A single layer film is a film containing only a single layer. This layer contains inorganic particles and / or air bubbles.

The two-layer structure film is a film having the structure of the A layer / B layer obtained by laminating the A layer and the B layer, and the inorganic particles and / or the bubbles are contained in at least one of the A layer and the B layer . The content of the inorganic particles is preferably 2% by mass or more, more preferably 7% by mass or more, further preferably 10% by mass or more, particularly preferably 2% by mass or more based on the total mass of the base film, Is not less than 30% by mass.

The three-layered film is a film having a structure of layer A / layer B / layer A or layer A / layer B / layer C, and at least one layer of each layer contains inorganic particles and / or bubbles . The inorganic particles are preferably not less than 2% by mass, more preferably not less than 7% by mass, further preferably not less than 10% by mass, particularly preferably not less than 30% by mass, based on the total mass of the substrate film, Mass% or more. In the case of a three-layer structure, it is most preferable that the B layer contains bubbles in terms of productivity.

The number average particle diameter of the inorganic fine particles contained in such a base film is preferably 0.3 to 2.0 占 퐉.

Examples of such inorganic particles include calcium carbonate, magnesium carbonate, zinc carbonate, titanium oxide, zinc oxide, cerium oxide, magnesium oxide, barium sulfate, zinc sulfide, calcium phosphate, silica, alumina, mica, mica titanium, talc, clay, Kaolin, lithium fluoride, calcium fluoride and the like can be used.

Next, a method for producing a thermoplastic resin film having a three-layer structure in the base film will be described. However, the present invention is not limited to this example.

First, a copolymer of polyethylene glycol, polybutylene terephthalate and polytetramethylene glycol as a low specific grafting agent is introduced into polyethylene terephthalate as an incompatible polymer. Sufficiently mixed and dried, and fed to an extruder B heated to a temperature of 270 to 300 ° C. Polyethylene terephthalate containing an additive of an inorganic substance and / or an organic substance such as BaSO ₄ , CaCO ₃ and TiO ₂ is fed to the extruder A by a conventional method. The polymer of the extruder B is arranged in the inner layer (B layer) and the polymer of the extruder A is arranged in both surface layers (A layer) in the T die 3 layer structure, Three layers are stacked.

A preferred method of producing the base film will be described below. The sheet on which the polymer is melted is tightly cooled and solidified on the drum at a drum surface temperature of 10 to 60 DEG C by electrostatic force to obtain an unstretched film. The unstretched film is led to a roll group heated at 80 to 120 캜, longitudinally stretched 2.0 to 5.0 times in the longitudinal direction, and cooled in a roll group of 20 to 50 캜. Subsequently, both ends of the longitudinally stretched film are guided by a tenter while grasping with a clip, and transversely stretched in a direction perpendicular to the length in an atmosphere heated to 90 to 140 캜. In this case, it is preferable that the stretching magnification is 2.5 to 4.5 times in both the longitudinal and transverse directions, but the area ratio (longitudinal stretching magnification x transverse stretching magnification) is preferably 9 to 16 times. That is, if the area magnification is small, the amount of bubbles and the amount of holes in the resulting film may not be sufficient. If the area ratio is too large, tearing tends to occur at the time of stretching, and the film-forming property may be lowered. In order to impart planarity and dimensional stability to the biaxially stretched film in this manner, the film was thermally fixed at 150 to 230 DEG C in a tenter, uniformly and slowly cooled, cooled to room temperature, To obtain a plastic resin film. The thickness of the base film is preferably set to, for example, 30 占 퐉 or more, preferably 100 or more, and 1,000 占 퐉 or less.

<< Particle Containing Layer >>

The reflective film of the present invention has a particle containing layer. It is preferable that the particle-containing layer is present adjacent to the base film. The method for forming the particle-containing layer is not particularly limited, but the following methods can be used.

(I) A method of bonding a resin layer containing particles to at least one surface of a base film, or applying a coating liquid containing particles, and drying the coating.

(II) A method for laminating a particle containing layer by extruding a resin material containing particles when the base film is produced by melt extrusion.

The preferable thickness of the particle-containing layer is 0.1 占 퐉 or more and 500 占 퐉 or less. When the thickness is more than 0.1 탆, scratches on the surface of the reflective film and scratches on the stripe shape are less likely to occur. If it is 500 탆 or less, the particle-containing layer can be formed favorably on the surface of the base film, and the reflection film is less likely to cause curling and the like, and planarity is improved.

<< Convex on the surface of the reflective film >>

The reflective film of the present invention has a convex portion on at least one side. The convex portion can be generated by particles included in the particle containing layer. Here, the contact of a plurality of convex portions is referred to as a collection of convex portions. In counting the number of convex portions, the aggregate is not counted as one convex portion, and is taken as the number of convex portions in the noted aggregate.

By providing the convex portion on either side of the reflective film, it is possible to prevent scratches such as dents and streaks on the reflective film surface, and to prevent unevenness caused by adhering the reflective film to the light guide plate. The presence and size of the convex portions can be confirmed by observing the surface of the reflective film with an electron microscope.

The reflective film of the present invention has at least one convex portion satisfying all the following requirements. Hereinafter, this surface will be referred to as a &quot; characteristic surface &quot;.

(i) convex portions having a diameter of 25 to 50 mu m.

(ii) the number of the convex portions having a diameter of 25 to 50 mu m independently from the convex portions having a diameter of 25 to 50 mu m is 10 to 100 per 0.64 square mm.

(iii) The number of convex portions included in the aggregate of the convex portions continuously contacting the convex portions having a diameter of 25 to 50 占 퐉 is 10 or less per 0.64 mm2.

The characteristic surface is preferably a surface of the particle-containing layer. A convex portion having a diameter of 25 to 50 mu m is present on the characteristic surface. Thus, it is preferable to prevent scratches such as dents and streaks on the surface of the reflective film, and to prevent unevenness of light generated by attaching the reflective film to the light guide plate.

Further, in the characteristic aspect, it is preferable that the convex portions having a diameter of 25 to 50 mu m exist independently of other convex portions having a diameter of 25 to 50 mu m without contacting as much as possible. Here, the &quot; convex portions having diameters of 25 to 50 mu m exist independently of other convex portions having diameters of 25 to 50 mu m independently of each other &quot; means that when observed with an electron microscope by a method described later, Means that the convex portion of 50 to 50 mu m in diameter is not in contact with the other convex portion of 25 to 50 mu m in diameter. Refers to a case where the shortest distance from the outermost portion of the convex portion to the outermost portion of the other convex portion is 0.005 m or less when two convex portions are observed by a method described later. That is, when the shortest distance from the outermost part of the convex part to the outermost part of the other convex part is larger than 0.005 mu m, it is not contacted.

The number of the convex portions which do not contact other convex portions having a diameter of 25 to 50 占 퐉 and existed independently and each having a diameter of 25 to 50 占 퐉 is 10 to 100 in 0.64 mm2. The lower limit is preferably 15 or more, more preferably 20 or more. The upper limit is preferably 75 or less, more preferably 50 or less. When the number of convex portions having a diameter of 25 to 50 占 퐉 that is not in contact with other convex portions having a diameter of 25 to 50 占 퐉 and exists independently is out of the above range, the effect of preventing the reflections of the reflecting film surface and preventing scratches The effect may not be exhibited.

In the present invention, there is also a case where an aggregate of convex portions in which convex portions having a diameter of 25 to 50 mu m are in contact with each other is formed in some cases. Here, the term &quot; aggregate of continuous convex portions &quot; means that two or more convex portions are in contact with each other. Whether or not "contact" is made is judged by the same method as the above-mentioned method.

It is preferable that the number of the projections included in the aggregate of the projections is 10 or less per 0.64 mm 2 in the aggregate of the projections having the diameter of 25 to 50 탆 continuously contacting the projections. Here, &quot; the number of the convex portions having a diameter of 25 to 50 占 퐉 is continuously in contact with 10 or less &quot; means that when a plurality of convex portions are continuously contacted to form an aggregate of convex portions, Quot; means that the number of convex portions is 10 or less per 0.64 mm &lt; 2 &gt;

In the aggregate of the convex portions, if the number of the convex portions is 10 or less per 0.64 mm 2, the occurrence of stripe-shaped defects is suppressed in the step of forming the particle containing layer.

The SRz in the surface roughness measurement of the characteristic surface is preferably 15 to 60 mu m. The lower limit of SRz is preferably 15 占 퐉 or more, more preferably 20 占 퐉 or more, and further preferably 25 占 퐉 or more. The upper limit of SRz is preferably 60 占 퐉 or less, more preferably 50 占 퐉 or less, and further preferably 45 占 퐉 or less. If SRz is too small, scratches such as dents and streaks on the surface of the reflective film may be lowered, and the effect of preventing unevenness caused by the reflective film adhering to the light guide plate may be deteriorated. If SRz is excessively large, scratches such as dents and streaks on the surface of the reflective film may become more conspicuous. When the grain diameter of the convex portion is made slightly larger, SRz becomes excessively large, and stripe-like defects are generated on the surface of the reflecting film in the step of forming the particle containing layer, or particles are dropped after the formation of the particle containing layer, There may be a case where an exfoliation occurs.

The method of forming convex portions on the characteristic surface is not particularly limited, and examples include the following methods.

When the particle-containing layer is produced by the method of (I), a suitable binder resin and particles are mixed with a suitable solvent (organic solvent or the like), the resulting mixture is applied to a base film and then dried, / RTI &gt;

In the case of producing the particle-containing layer by the production method of the above (II), particles are previously kneaded in the resin for forming the particle-containing layer in the step of producing the film by melt extrusion, and the resultant is extruded together with the resin for forming the base film , And forming convex portions in the particle-containing layer in the drawing step.

Of these, a method of applying the mixture to a base film is preferable in terms of achieving economical high performance.

<< Particles of the particle-containing layer >>

The material of the particles is not particularly limited, and organic or inorganic materials can be used. As for the shape, either spherical particles or particles having other shapes can be selected. In order to impart the feature of the convex portion of the present invention, spherical particles are preferable. Examples of the organic particles include acrylic resin particles, silicone resin particles, nylon resin particles, styrene resin particles, polyethylene resin particles, polypropylene resin particles, benzoguanamine resin particles, urethane resin particles, Can be used. As the inorganic particles, silica, aluminum hydroxide, aluminum oxide, zinc oxide, barium sulfide, magnesium silicate and mixtures thereof can be used.

When the particle-containing layer is formed by coating, a binder resin is usually contained in the coating liquid. In the case of using a binder resin containing a copolymer of an acrylic monomer and an ultraviolet absorber described later, the acrylic resin particles, the polyethylene-based resin, and the ultraviolet absorber are preferably selected from the relationship between the refractive index difference of the binder resin and the particles, It is preferable to use resin particles, silicone resin particles, nylon resin particles, urethane resin particles, and polyester resin particles. Further, polyethylene-based resin particles and nylon-based resin particles are more preferable from scratch resistance to the light guide plate. From the viewpoint of white point unevenness, preferred particles are nylon resin particles, and most preferably resin particles comprising nylon 12 resin particles and / or copolymers of nylon 6 and nylon 12. On the other hand, a polyethylene-based resin particle is preferable as a particle which is unlikely to cause stripe-shaped defects generated in the step of forming the particle-containing layer. Two or more kinds of particles having different particle materials among these particles may be used in combination.

In the present invention, the particle-containing layer contains particles having a particle diameter of 25 to 50 mu m and particles having a particle diameter of 1 to 15 mu m. It is preferable to contain the particles having a particle diameter of 25 to 50 占 퐉 in the particle-containing layer because convex portions having a diameter of 25 to 50 占 퐉 can be suitably formed.

Also, by containing particles having a particle diameter of 1 to 15 占 퐉, convex portions of 25 to 50 占 퐉 in diameter exist independently of other convex portions having a diameter of 25 to 50 占 퐉 as much as possible and independently exist, It is easy to make the number of parts within the scope of the present invention. That is, when the particles contain particles having a diameter of 1 to 15 탆, the convex portions having a diameter of 25 to 50 탆 have a larger chance of being in contact with convex portions formed of particles having a particle diameter of 1 to 15 탆, It is difficult to contact other convex portions having a diameter of 25 to 50 mu m. Convex portion having a diameter of 25 to 50 mu m is preferably made to contain particles having a particle diameter of 1 to 5 mu m, Lt; RTI ID = 0.0 &gt; um. &Lt; / RTI &gt;

Here, the particle diameter of the particles is a square or a rectangle in which the particles are in contact with the four sides of the particles and the area is minimized by observing the particles. In the case of a square, the length is one side, and in the case of a rectangle, a length is long.

In the particle-containing layer of the present invention, it is preferable to use two or more kinds of particles having different particle diameters in combination. By using two or more kinds of particles having different particle diameters in combination, it is possible to effectively form particles having a particle diameter of 25 to 50 μm and particles containing particles having a particle diameter of 1 to 15 μm.

The addition amount of the particles is not particularly limited, but is preferably at least 17 mass%, more preferably at least 19 mass%, based on the whole particle-containing layer. On the other hand, it is preferably 90 mass% or less, more preferably 60 mass% or less, and further preferably 56 mass% or less. The amount of these particles to be added is the sum of two or more kinds of all the particles when two or more kinds of particles are used in combination. The effect of preventing scratches such as dents and streaks on the surface of the reflective film may be deteriorated even when the addition amount is too small or too large. In addition, when the added amount is too large, stripe-like defects are generated in the step of forming the particle-containing layer, which may cause a problem in the previous step of using the reflective film.

The amount of the particles having a particle diameter of 25 to 50 mu m or more is preferably 7 mass% or more and 55 mass% or less with respect to the whole particle-containing layer. More preferably 9% by mass or more, and further preferably 12% by mass or more. And more preferably 40 mass% or less. The addition amount of the particles having a particle diameter of 1 to 15 mu m is preferably 10 mass% or more and 35 mass% or less with respect to the whole particle-containing layer. The upper limit is more preferably 24 mass% or less, and still more preferably 16 mass% or less.

The preferable mass ratio (particle weight of the electron / particle weight of the latter) of the particles having a particle diameter of 25 to 50 mu m or more and the particles having a particle diameter of 1 to 15 mu m is not less than 0.61 and not more than 6.49. More preferably 0.63 or more and 5.5 or less, still more preferably 0.63 or more and 2.5 or less, further preferably 0.75 or more and 2.5 or less.

<< Resin other than particle of particle-containing layer >>

When the particle-containing layer is formed on at least one side of the base film by coating the coating solution, the binder resin is not particularly limited, and examples thereof include polyester resin, polyurethane resin, acrylic resin, methacrylic resin, polyamide resin, A polyethylene resin, a polypropylene resin, a polyvinyl chloride resin, a polyvinylidene chloride resin, a polystyrene resin, a polyvinyl acetate resin, a fluorine resin, and a silicone resin. These resins are suitably used as resins other than the particles even when the particle-containing layer is formed by a method other than coating. These resins may be used alone or in combination of two or more. Among them, a polyester resin, a polyurethane resin, an acrylic resin and a methacrylic resin are preferably used from the viewpoints of heat resistance, dispersibility of the particles, coatability of the coating solution and gloss of the resulting reflective film.

From the viewpoint of the light resistance of the particle-containing layer, it is preferable that the particle-containing layer contains an ultraviolet absorber and a light stabilizer. As the ultraviolet absorber and light stabilizer, there are inorganic and organic systems. The form contained therein is not particularly limited, and a resin forming such a particle-containing layer may be mixed with an ultraviolet absorber or a light stabilizer. On the other hand, when it is desired to prevent the ultraviolet absorber or the light stabilizer from bleeding out from the particle-containing layer, it may be copolymerized with the monomer of the resin contained in the particle-containing layer. It may also be chemically bonded to the resin involved.

Titanium oxide, zinc oxide, and cerium oxide are generally known as inorganic ultraviolet absorbers. Among them, at least one species selected from the group consisting of zinc oxide, titanium oxide, and cerium oxide is not bleed out, and is excellent in economy, light resistance, , And is preferably used because it has excellent photocatalytic activity. These ultraviolet absorbers may be used in combination of several kinds as necessary. Among them, zinc oxide or titanium oxide is most preferable from the viewpoints of economical efficiency, ultraviolet ray absorbing property and photocatalytic activity.

Examples of the organic ultraviolet absorber include benzotriazole and benzophenone. Particularly, benzotriazole can be suitably used because it contains nitrogen in the structure and thus has a function as a flame retardant, but is not limited thereto. These ultraviolet absorbers only absorb ultraviolet rays and can not capture organic radicals generated by irradiation with ultraviolet rays, so that the thermoplastic resin film of the substrate may be deteriorated in succession by these radicals. For capturing these radicals and the like, a light stabilizer is suitably used in combination. As such a light stabilizer, a hindered amine compound (HALS) is preferably used.

When the ultraviolet absorber has the shape of a particle, whether inorganic or organic, it may be used as particles having a particle diameter of 25 to 50 mu m or particles having a particle diameter of 1 to 15 mu m.

Here, as a monomer capable of copolymerizing for fixing the organic ultraviolet absorber or the light stabilizer, a vinyl-based monomer such as an acryl-based or styrene-based monomer has high versatility and is also economically preferable. Among these monomers, the styrene-based vinyl monomer tends to be yellowish because it has an aromatic ring. From the viewpoint of light resistance, copolymerization with an acrylic monomer is most preferably used.

Further, 2- (2'-hydroxy-5'-methacryloxyethylphenyl) -2H-benzotriazole (trade name: RUVA-93) in which a reactive vinyl monomer is substituted for benzotriazole; Manufactured by Otsuka Chemical Co., Ltd.) can be used. Also, a combination of a hindered amine compound and a reactive vinyl monomer is 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine ("Adekastab " LA-82 (Available from Adeka Co., Ltd.) can be used.

In the present invention, examples of such organic ultraviolet absorbers include resins containing organic ultraviolet absorbers such as benzotriazole and benzophenone, resins obtained by copolymerizing benzotriazole-based or benzophenone-based monomers, hindered amines (HALS) Or a resin containing a photo-stabilizer such as a reactive monomer and / or a copolymer.

Organic ultraviolet absorbing resins including resins obtained by copolymerizing benzotriazole-based and benzophenone-based reactive monomers, and resins obtained by copolymerizing these with hindered amine (HALS) -based reactive monomers are more preferred because of their high ultraviolet absorbing effect, Among them, benzotriazole is particularly preferable because it contains nitrogen in the structure and therefore also acts as a flame retardant.

The manufacturing method and the like of these are described in detail in paragraphs [0019] to [0039] of Japanese Patent Application Laid-Open No. 2002-90515. A "Hals hybrid" (registered trademark) (Nippon Shokubai Co., Ltd.) containing a copolymer of an acrylic monomer and an ultraviolet absorber as an active ingredient may be used.

&Lt; Method of forming particle-containing layer by coating &gt;

Any method may be employed for forming the particle-containing layer on at least one surface of the base film by coating. For example, the coating liquid containing the binder resin and the particles in a solvent may be applied to the surface of the substrate by gravure coating, roll coating, spin coating, reverse coating, reverse kiss coating, bar coating, screen coating, blade coating, A method of coating the base film with various coating methods such as coating and dipping, or applying the base film to the base film after the crystal orientation is completed, and the like. The former application method is referred to as in-line coating and the latter application method is referred to as &quot; off-line coating &quot;. When there is little restriction on the coating effective width, and when it is desired to flexibly cope with the change in the product width, reverse kiss coating can be most preferably used.

The solvent usable for mixing the binder resin and particles constituting the particle-containing layer is a liquid having a property of dissolving the binder resin. After the coating liquid is applied on the surface of the base film, the solvent is vaporized. Examples of the solvent include aromatic hydrocarbons such as toluene, xylene and styrene, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, alcohols such as methanol, isopropyl alcohol and isobutyl alcohol, Chlorinated aliphatic hydrocarbons such as monochloromethane and monochloroethane; esters such as methyl acetate, ethyl acetate and butyl acetate; ethers such as ethyl ether and 1,4-dioxane; Glycol ethers such as ethylene glycol monomethyl ether, alicyclic hydrocarbons such as cyclohexane, and aliphatic hydrocarbons such as normal hexane. Among them, aromatic hydrocarbon-based, ketone-based, and ester-based organic solvents are preferable.

Is not particularly limited as long as it dissolves a binder resin and the like. However, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate and butyl acetate are preferable in terms of solubility, versatility and cost. It is also preferable to mix two or more kinds of solvents having different boiling points in that the drying rate can be adjusted.

&Lt; Other additives usable in the base film and the particle-containing layer &gt;

The base film and the particle-containing layer may contain various additives. Such additives include, for example, fluorescent whitening agents, crosslinking agents, heat stabilizers, oxidation stabilizers, organic lubricants, antistatic agents, nucleating agents, dyes, pigments, fillers, dispersants, flame retardants and coupling agents.

&Lt; Use of reflective film &

INDUSTRIAL APPLICABILITY The reflective film of the present invention can be suitably used for an edge light type backlight for a liquid crystal display, an edge light type backlight for a liquid crystal display, and a surface light source for a signboard or a vending machine.

In addition, it can be suitably used as a sealing film or a back sheet of a reflective film constituting various surface light sources or a solar cell module requiring reflection characteristics. In addition, it is possible to use paper substitutes, such as cards, labels, seals, courier slips, image receiving papers for video printers, inkjets, award sheets for barcode printers, posters, maps, dust- A sheet of a receiving sheet used for various printing records such as offset printing, a telephone card, and an IC card, a building material such as wallpaper, a lighting device or an indirect lighting device used indoors or outdoors, a member mounted on an automobile, a railroad, , A circuit material, and the like.

<Edge light type backlight>

<< Configuration of edge light type backlight >>

The reflective film of the present invention is suitably used for an edge light type backlight. In the edge light type backlight, for example, the reflective film and the light guide plate of the present invention are assembled in this order in a housing, and the reflective film is assembled such that the side of the particle containing layer faces the light guide plate. Further, a light source such as an LED is provided at an edge portion of the light guide plate. An optical film such as a diffusion film or a prism film may be provided on the front surface of the light guide plate (opposite to the reflective film).

By using the reflective film of the present invention in such an edge light type backlight, a high quality backlight free from optical nonuniformity can be obtained.

The size (rectangular diagonal length) of the backlight for a liquid crystal display using an LED as a light source that exhibits the effect of the present invention more effectively is preferably at least 76.2 cm (30 inches), preferably at least 88.9 cm (35 inches) Is at least 101.6 cm (40 inches), particularly preferably at least 127 inches (50 inches).

It is also preferable that the light guide plate has a concave portion or convex portion of 3 占 퐉 or more on the surface of the light guide plate in the edge light type backlight. It is preferable that a concave portion or a convex portion of 10 占 퐉 or more is formed.

The surface irregularities of the light guide plate are defined as follows.

(i) Take out the light guide plate disposed on the reflective film from the liquid crystal TV.

(ii) The light guide plate is cut into a quadrangle of 5 cm on one side, and arbitrary five pieces are taken out.

(iii) Using a laser microscope VK-9700 manufactured by Keith Co., the magnification of the objective lens is set at 20 magnifications and observation is performed. The surface irregularities are detected at a height or depth of 1 mu m or more.

As the material of the light guide plate, acrylic resin, resin obtained by mixing acrylic resin and styrene resin, styrene resin, glass and the like are used.

The light guide plate 2 having a convex portion as shown in Fig. 2 in which dot printing is performed is preferable from the viewpoint of production capability. Further, since the light guide plate having concave portions formed by laser machining, or the light guide plate having convex portions or concave portions formed by molding using a mold or a roll, is hard to cause loss such as light absorption in the dot printing portion, It is preferable in terms of high points.

Example

Hereinafter, the present invention will be described in more detail with reference to examples. But the present invention is not limited to these examples. First, the measurement method and the evaluation method are shown below.

(1) Material of the particles contained in the particle-containing layer

Using a microscope (SMZ 1500, Nikon Corporation), the particles included in the projections were sampled with a metallic jig while observing the surface of the particle-containing layer by appropriately adjusting the overall magnification to 20 to 200 times, thereby obtaining a sample to be measured.

The obtained sample was further cut, and the vicinity of the center of the particle was measured by a brown rice FT-IR method.

The particle sampling, the cutting treatment, and the measurement by the brown rice FT-IR method were carried out at two points for convex portions of 25 μm or more and at two points for convex portions of 15 μm or less.

Next, the material of the particles included in the convex portions was determined from the infrared light absorption waveform of the brown rice FT-IR obtained above.

The apparatus names and measurement conditions used in the brown rice FT-IR method are shown below.

Apparatus: R &amp; D infrared spectroscopic analyzer IRs (manufactured by SPECTRA-TECH)

Condition:

 Light source Silicon carbide rod heating element (Globa)

 Detector Narrow · MCT (HgCdTe)

Detection wave range 4000 to 650 cm ^-1

 Fudge Nitrogen gas

 Measurement mode Transmission

Resolution 8 cm ^-1

 Accumulated count 512 times

Data correction: baseline correction.

(2) Mass of the particle-containing layer

The reflective film was cut into 100 mm long × 100 mm wide and mass was measured. This value was defined as mass 1. Next, the reflection film was placed on the upper surface of the reflective film, and the reflection film was placed on a mass scale (Yamato, product number SD-12, use range 500 to 12 kg, scale interval 50 g, type approval D9812, I put it on a plate. At this time, a double-sided tape was attached to the back surface of the four corners of the reflective film to fix the dish and the reflective film of the mass scale. Subsequently, a nonwoven fabric ("Hijegazu ", NT-4, 25 cm x 25 cm, Section 4, issued by Kawamoto Sangyo K.K.) Mm so as to cover the bottom of one side of the metal rod which is in the shape of a quadrangular prism. Next, the particle-containing layer of the reflective film fixed on the dish of the mass balance was rubbed with the surface of the nonwoven fabric with the nonwoven fabric attached to the nonwoven fabric on which the nonwoven fabric was attached, with a load of 1.5 to 2.5 kg. The entire surface of the particle-containing layer having a length of 100 mm and a width of 100 mm is rubbed by repeating this operation ten times while moving the operation side by side. Next, the double-sided tape was peeled off, the reflective film was peeled off from the dish of the weight scale, allowed to stand at room temperature to evaporate the methyl ethyl ketone, and then the mass was measured. This value was defined as mass 2. The mass of the particle-containing layer was obtained by calculating (mass 1 - mass 2).

(3) The ratio of the amount of particles in the particle-

After the particle-containing layer was shrunk by about 10 mg, the mass was accurately measured. This mass is defined as mass 3. Then, 25 ml of MEK was weighed and placed in a cylindrical glass bottle having a capacity of 50 ml and a diameter of 35 mm attached with a lidded particle-containing layer. Subsequently, a stirrer was placed in a glass bottle, stirring was performed for 24 hours, and then the stirrer was taken out. Then, a filter paper ("OMNIPORE" manufactured by MILLIPORE, CAT NO. JGWP 02500) was cut into a circular shape having a diameter of 21 mm and its mass was measured. This value is set as mass 4. After the measurement, the filter paper was placed in a funnel (Kyoriyama Seisakusho Co., Ltd., SB-21, 21φ), the funnel was set in a suction bottle for filtration under reduced pressure, a liquid of a glass bottle was placed in a funnel, . The filter paper after the filtration work was placed on a hot plate set at 90 DEG C, the methyl ethyl ketone was dried, and the mass of the filter paper after filtration was measured. This value is set to mass 5. The particle amount ratio in the particle-containing layer was calculated by the following formula.

Content ratio of particles in the particle containing layer = (mass 5 - mass 4) / mass 3.

(4) SRz

Using a Surf Coda ET4000A with a fine shape measuring instrument Kosaku, the SRz of the surface of the reflecting film was measured under the following conditions. Three randomly selected portions were measured, and their average value was defined as SRz.

Measuring terminal: made of diamond, tip R = 2 탆

Measuring force: 100 μN

Measuring length: 1 mm

Measuring speed: 0.1 mm / sec

Cutoff setting: R + W.

(5) the presence of particles having a particle diameter of 25 to 50 mu m and particles having a particle diameter of 1 to 15 mu m

The reflective film was cut at a randomly selected position and observed at a magnification of 1,000 times with a scanning electron microscope (S-3400N, Hitachi Seisakusho Co., Ltd.). A square or a rectangle in which the particle is in contact with the four sides and has the smallest area is drawn. In the case of a square, a length of one side is adopted. In the case of a rectangle, a length of a long side is adopted. By this method, the particle diameter of each of 500 randomly selected particles was measured.

Further, when 500 particles were not observed in one image, an image of a cut cross section was taken at a different position of the reflection sheet, and the particle diameter of 500 particles in total was measured. If there are one or more particles in the range of the respective particle diameters among 500 particles, it is determined that particles in the range of the respective particle diameters are present. In Table 2, "presence" is described when particles are present, and "not present" is described when they are not present.

(6) The number of convex portions having diameters of 25 to 50 占 퐉 which do not contact convex portions having diameters of 25 to 50 占 퐉 and exist independently

The outline of the convex portion was observed with a scanning electron microscope (S-3400N, Hitachi, Ltd.) at a magnification of 100 times and an acceleration voltage of 7.50 kV. The visual field of the image at a magnification of 100 times was 1.27 mm x 0.885 mm. The center of this image was selected to be 0.8 mm x 0.8 mm and the number of convex portions having diameters of 25 to 50 mu m independently existing without touching convex portions with diameters of 25 to 50 mu m was added. Here, the diameter of the convex portion is a square or a rectangle in which the outline is in contact with the outline of the convex portion of the SEM image so that the area becomes the smallest, and the length of one side in the case of a square or the long side in the case of a rectangle, Employed as the diameter of the negative.

Whether or not the convex portion is &quot; contacted &quot; was judged by the following operation. The image was printed out on paper so that 50 mu m in the image photographed at a magnification of 100 times was 10 mm. The printed out paper was observed with a universal projector (model number: V-16A, Nikon Corporation, observation limit: 0.001 mm). At this time, 0.001 mm in the universal projector corresponds to 0.005 m in the image photographed at 100 times. The shortest distance from the outermost part of the particle to the outermost part of the other convex part with respect to the entire convex part included in the image was measured and found to be 0.001 mm or less (i.e., 0.005 m or less in the image photographed at 100 times) ), It was judged that the convex portion was &quot; contacted &quot;. In addition, when the shortest distance from the outermost portion of the convex portion to the outermost portion of the other convex portion is measured and is larger than 0.001 mm (that is, a distance larger than 0.005 m in an image photographed at 100 times) It was judged that the additional "contact" was not made.

The surface of the reflecting film was measured at five different positions, and the average of the five portions was determined as the number of convex portions having a diameter of 25 to 50 占 퐉 independently existing without contacting the convex portions having a diameter of 25 to 50 占 퐉. Also, the mean value rounded to the nearest decimal point.

Here, the diameter of the convex portion is a square or a rectangle in which convex portions are in contact with the four sides to minimize the area, and a length of one side in the case of a square and a length of a long side in the case of a rectangle are employed.

(7) The number of convex portions included in the aggregate of the convex portions with which the convex portions with the diameter of 25 to 50 占 퐉 are in contact with each other continuously

The surface of the reflective film was observed with a scanning electron microscope (S-3400N, Hitachi, Ltd.) at a magnification of 100 times. The visual field of the image at a magnification of 100 times was 1.27 mm x 0.885 mm. The center of this image was selected to be 0.8 mm x 0.8 mm, and the number of projections included in the aggregate of convex portions, in which the convex portions with diameters of 25 to 50 mu m continuously contacted, were added. When a plurality of aggregates are visible in the obtained image, the number of convex portions included in each aggregate is added to all the aggregates. Also, the judgment as to whether or not the contact was made was made by the same method as the above-mentioned method.

Measurements were made on ten aggregates in which convex portions with diameters of 25 to 50 mu m were continuous, and the average of the number of convex portions that were in contact with each other was obtained. In Table 2, &quot; 10 or less &quot; is described when the average value of the number of convex portions is 10 or less, and &quot; exceeds 10 &quot;

(8) Evaluation of dispersibility of particles

25 ml of the coating solution prepared in the examples and comparative examples was weighed, placed in a glass bottle (cylindrical shape having a diameter of 35 mm) having a capacity of 50 ml with a lid, and left to stand for 24 hours with the lid closed. After 24 hours had elapsed, the coating liquid entering the glass bottle was visually observed and the following judgment was made.

AA grade: No separation was observed in the liquid phase, or separation appeared in the liquid phase (separated into small particles and many particles). However, the height of the phase with less particles was one third or less of the height of the liquid.

Class A: Separation was observed in the liquid phase (separated into small particles and many particles), and the height of the small particles was larger than one-third of the height of the liquid and less than four-fifths.

Class B: Separation was observed in the liquid phase (separated into small particles and many particles), and the height of the small particles was larger than that of the whole liquid.

(9) Scratches of reflective film

BISIX " (registered trademark) color magnet, circle, diameter of 20 mm, product number: BX4-13-YL (trade name, manufactured by Mitsuya Kogyo Co., Ltd.) on one side of an acrylic plate of 50 mm in length x 50 mm in width and 3 mm in thickness (Yellow)) were attached. Each of the magnets was brought into contact with each other so that the line connecting the centers of the magnets was a regular triangle, and the center of the triangle was the center of the acrylic plate. Attachment used double-sided tape. The magnets were arranged so that the magnet face of the magnet was on the acrylic plate side and the resin face of the magnet was opposite to the acrylic plate.

Subsequently, a 32-inch liquid crystal display (32-inch liquid crystal TV (model number: LHD32K15JP) manufactured by HiSense Japan Co., Ltd.) was disassembled and an edge light type backlight (hereinafter referred to as "backlight A" did. Further, a light guide plate (acrylic plate, 4 mm thick) having a convex shape on one side was taken out and cut into 50 mm x 100 mm.

Next, a reflective film cut out to a size of 50 mm x 100 mm was overlaid on the surface side of the convex portion of the light guide plate so that the surface on which the particle-containing layer was laminated contacted.

Subsequently, the acrylic plate having the magnet described above was superimposed on the reflective film so that the two edges of the acrylic plate overlapped with the two edges of the overlapping reflective film and the light guide plate, respectively. So that the resin surface of the magnet is brought into contact with the reflective film in the overlapping.

Further, a weight was placed on the acrylic plate on the side where the magnet was not attached. The weighing was carried out in two cases: a case in which four 100 g weights having a diameter of 34 mm and a thickness of 13 mm were overlapped and a case in which a weight of 750 g having a diameter of 48 mm and a thickness of 45 mm was placed.

Next, the end portion of the reflection film on which the acrylic plate was not overlapped was held by hand, and the film was stretched 50 mm over 3 seconds in the direction opposite to the acrylic plate in the direction perpendicular to the thickness direction of the reflection film. At this time, the reflective film and the acrylic plate with the magnet moved together and moved on the light guide plate.

After carrying out the above operation, the reflecting film was taken out, and a three-wavelength fluorescent lamp (FHF32EX-NH manufactured by Toshiba Latec Co., Ltd., Hf "Mero line" (registered trademark of Japanese character) fluorescent lamp, tri- I put a reflective film on my desk. At this time, the reflection film was placed just below the fluorescent lamp so that the particle-containing layer was opposed to the desk, and scratches of the reflection film were observed. The observation was made so that the angle formed by the straight line of the reflection film face and the portion of the reflection film on which the acrylic plate was placed was 45 degrees. B, C and D grades according to the following criteria.

A grade: No scratches even at 400g weight and 750g weight

B grade: 400g weight does not show scratches but 750g weight shows faint scratches

Class C: 400g The fog looks blurred in the weight, and the flaw appears clearly in the 750g weight

D grade: 400g weight and even 750g weight, clearly visible scratches.

(10) Evaluation of light guide plate cutting

A light guide plate (acrylic plate, 4 mm thick) having a convex portion formed on one side thereof was taken out from the backlight A, and laminated so that the surface on which the convex portion of the obtained light guide plate was laminated was in contact with the surface on which the particle- And a load of 175 gf / cm &lt; 2 &gt;, and the reflective film sample was stretched at a linear velocity of 1 m / min in a direction perpendicular to the thickness direction of the reflective film. Thereafter, the degree of scratches on the convex portion of the light guide plate was observed with a magnification of the objective lens being 20 times and a display magnification of 100%, using a laser microscope VK-9710 manufactured by Keith Co. And evaluated according to the following criteria.

Class A: Scratches are not visible under any load.

Class B: Scratches are observed under a load of 175 gf / cm 2, but no scratches are observed under a load of 50 gf / cm 2.

(Example 1)

180 g of "HALS Hybrid" UV-G720T (acrylic copolymer, solution with a concentration of 40 mass%, Nippon Shokubai Co., Ltd.), 236.4 g of ethyl acetate, 12 g of nylon resin particles (SP20 made by TORAY CO., LTD., Volume average particle diameter: 30 탆) containing silica particles, 12 g of acrylic resin particles having particle diameters in the range of 1 to 15 탆 (manufactured by Sekisui Plastics Co., (Trade name: " TECHPOLYMER "(registered trademark) MBX5, volume average particle diameter: 5 mu m) were mixed and stirred to prepare a coating solution. On one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing biaxially oriented polyethylene terephthalate with porous biaxial thickness of 300 μm, And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Example 2)

180 g of "HALS Hybrid" UV-G720T (acrylic copolymer, solution with a concentration of 40 mass%, Nippon Shokubai Co., Ltd.), 236.4 g of ethyl acetate, , 12 g of polyethylene resin particles (molecular weight: 200 x 10 ⁴ , melting point: 136 캜, volume average particle diameter: 30 탆) containing acrylic resin particles (manufactured by Sekisui Plastics Co., Ltd.) containing particles having a diameter in the range of 1 to 15 탆 16 g of "TECH POLYMER" (trade name) MBX5, volume average particle diameter 5 mu m) were stirred to prepare a coating solution. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate having a thickness of 300 μm using MetaBa # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute. The molecular weight of the polyethylene resin particles was calculated from IV [?] (Dl / g), and the melting point was calculated according to ASTM D 3418.

(Example 3)

180 g of "HALS Hybrid" UV-G720T (acrylic copolymer, solution with a concentration of 40% by mass, Nippon Shokubai Co., Ltd.), 236.4 g of ethyl acetate, 12 g of the polyethylene resin particles used in Example 2, 16 g of nylon resin particles (SP500, manufactured by Toray Co., Ltd., volume average particle diameter: 5 mu m) containing particles having a particle diameter in the range of 1 to 15 mu m were agitated to prepare a coating solution. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate with a thickness of 300 μm using METABA # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Example 4)

180 g of "HALS Hybrid" UV-G720T (acrylic copolymer, solution with a concentration of 40 mass%, Nippon Shokubai Co., Ltd.), 236.4 g of ethyl acetate, 12 g of nylon resin particles (SP20 made by TORAY CO., LTD., Volume average particle diameter 30 탆) containing particles of polyethylene resin particles having a diameter of 1 to 15 탆 (molecular weight 180 × 10 ⁴ , melting point 136 ° C., Volume average particle diameter 5 mu m) were stirred to prepare a coating solution. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate with a thickness of 300 μm using METABA # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute. The molecular weight of the polyethylene resin particles was converted from IV [?] (Dl / g). The melting point was also calculated according to ASTM D 3418.

(Example 5)

180 g of "HALS Hybrid" UV-G720T (acrylic copolymer, concentration 40% by mass, Nippon Shokubai Co., Ltd.), 236.4 g of ethyl acetate, 12 g of the polyethylene resin particles used in Example 2, 16 g of the polyethylene resin particles used in Example 4 were stirred to prepare a coating solution. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate with a thickness of 300 μm using METABA # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Example 6)

180 g of "HALS Hybrid" UV-G720T (acrylic copolymer, solution with a concentration of 40 mass%, Nippon Shokubai Co., Ltd.), 236.4 g of ethyl acetate, 12 g of nylon resin particles (SP20 made by TORAY CO., LTD., Volume average particle diameter: 30 탆), 12 g of nylon resin particles (SP500, manufactured by Toray Co., Ltd.) containing particles having a diameter in the range of 1 to 15 탆, Diameter: 5 mu m) were stirred to prepare a coating solution. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate with a thickness of 300 μm using METABA # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Example 7)

110 g of "HALS Hybrid" UV-G720T (acrylic copolymer, solution having a concentration of 40 mass%, Nippon Shokubai Co., Ltd.), 278.4 g of ethyl acetate, 40 g of nylon resin particles (SP20 made by TORAY CO., LTD., Volume average particle diameter: 30 탆) containing nylon resin particles (SP500, manufactured by Toray Co., Ltd.) containing particles having a diameter in the range of 1 to 15 탆, Diameter: 5 mu m) were stirred to prepare a coating solution. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate with a thickness of 300 μm using METABA # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Example 8)

110 g of "HALS Hybrid" UV-G720T (acrylic copolymer, solution having a concentration of 40 mass%, Nippon Shokubai Co., Ltd.), 278.4 g of ethyl acetate, , 40 g of nylon resin particles (volume average particle diameter: 40 탆), 16 g of nylon resin particles (SP500, manufactured by Toray Co., Ltd., volume average particle diameter: 5 탆) containing particles having a diameter in the range of 1 to 15 탆, I prepared the sake. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate with a thickness of 300 μm using METABA # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Example 9)

202.5 g of "HALS Hybrid" UV-G720T (acrylic copolymer, solution having a concentration of 40% by mass, Nippon Shokubai Co., Ltd.), 222.9 g of ethyl acetate, particles having a diameter of 25 to 50 μm , 9 g of nylon resin particles (SP20 made by TORAY CO., LTD., Volume average particle diameter 30 탆) containing particles having a diameter in the range of 1 to 15 탆, SP10 made by Toray Co., Particle diameter 10 mu m) was stirred to prepare a coating solution. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate with a thickness of 300 μm using METABA # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Example 10)

207.5 g of "HALSHYBRID" (registered trademark) UV-G720T (acrylic copolymer, solution having a concentration of 40% by mass, Nippon Shokubai Co., Ltd.), 219.9 g of ethyl acetate, , 7 g of nylon resin particles (SP20 made by TORAY CO., LTD., Volume average particle diameter 30 탆) containing particles having a diameter in the range of 1 to 15 탆, SP10 made by Toray Co., Particle diameter 10 mu m) was stirred to prepare a coating solution. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate with a thickness of 300 μm using METABA # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Example 11)

107.5 g of "HALS Hybrid" UV-G720T (acrylic copolymer, solution with a concentration of 40% by mass, Nippon Shokubai Co., Ltd.), 724.4 g of ethyl acetate, , 22 g of nylon resin particles (volume average particle diameter: 50 탆), 35 g of nylon resin particles (SP500, manufactured by Toray Co., Ltd., volume average particle diameter: 5 탆) containing particles having a diameter in the range of 1 to 15 탆 And the solution was prepared by stirring. This coating solution was applied to one surface of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate having a thickness of 300 μm using Metaba # 40 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Example 12)

207.5 g of "HALSHYBRID" (registered trademark) UV-G720T (acrylic copolymer, solution having a concentration of 40% by mass, Nippon Shokubai Co., Ltd.), 219.9 g of ethyl acetate, , 7 g of nylon resin particles (volume average particle diameter: 25 탆), 10 g of nylon resin particles (SP10 made by Toray Co., Ltd., volume average particle diameter: 10 탆) containing particles having a diameter in the range of 1 to 15 탆 And the solution was prepared by stirring. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate with a thickness of 300 μm using METABA # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Example 13)

87.5 g of ethyl acrylate, 736.4 g of ethyl acetate, 90 g of nylon resin particles (volume average particle diameter: 60 탆), " HALSHYBRID "(registered trademark) UV-G720T (acrylic copolymer, concentration 40 wt.% Solution, Nippon Shokubai Co., And 10 g of nylon resin particles (volume average particle diameter: 2 m) were stirred to prepare a coating. This coating solution was applied to one surface of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate having a thickness of 300 μm using Metaba # 40 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Example 14)

37.5 g of ethyl acrylate, 321.9 g of ethyl acetate, 20 g of nylon resin particles (volume mean particle diameter: 20 mu m), " HALS Hybrid "UV-G720T (acrylic copolymer, concentration 40% And 30 g of nylon resin particles (volume average particle diameter 15 占 퐉) were stirred to prepare a coating solution. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate with a thickness of 300 μm using METABA # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Example 15)

102.5 g of "HALS Hybrid" UV-G720T (acrylic copolymer, solution having a concentration of 40% by mass, Nippon Shokubai Co., Ltd.), 282.9 g of ethyl acetate, particles having a diameter of 25 to 50 μm , 35 g of nylon resin particles (volume average particle diameter: 25 탆), and 24 g of nylon resin particles (SP500, manufactured by Toray Co., Ltd., volume average particle diameter: 5 탆) containing particles having a diameter in the range of 1 to 15 탆 And the solution was prepared by stirring. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate with a thickness of 300 μm using METABA # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Comparative Example 1)

210 g of "HALS Hybrid" UV-G720T (acrylic copolymer, solution having a concentration of 40 mass%, Nippon Shokubai Co., Ltd.), 218.4 g of ethyl acetate, , 6 g of nylon resin particles (SP20 made by TORAY CO., LTD., Volume average particle diameter: 30 탆) containing nylon resin particles (SP500 manufactured by TORAY CO., LTD. Containing particles having a diameter in the range of 1 to 15 탆, Diameter: 5 mu m) was stirred to prepare a coating solution. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate with a thickness of 300 μm using METABA # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Comparative Example 2)

62.5 g of "HALS Hybrid" UV-G720T (acrylic copolymer, concentration 40% by mass, Nippon Shokubai Co., Ltd.), 306.9 g of ethyl acetate, nylon resin particles (SP20, Volume average particle diameter 30 mu m) and 10 g of nylon resin particles (SP500, manufactured by Toray Co., Ltd., volume average particle diameter: 5 mu m) were stirred to prepare a coating solution. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate with a thickness of 300 μm using METABA # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Comparative Example 3)

175 g of "HALSHYBRID" (registered trademark) UV-G720T (acrylic copolymer, solution having a concentration of 40% by mass, Nippon Shokubai Co., Ltd.), 239.4 g of ethyl acetate, 20 g of acrylic resin particles (manufactured by Sekisui Plastics Co., -127, volume average particle diameter 27 mu m) was stirred to prepare a coating solution. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate with a thickness of 300 μm using METABA # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Comparative Example 4)

100 g of "HALS Hybrid" UV-G720T (acrylic copolymer, concentration 40% by mass, Nippon Shokubai Co., Ltd.), 284.4 g of ethyl acetate, nylon resin particles (SP20 made by Toray Co., Average particle diameter 30 mu m) and 54 g of nylon resin particles (SP500, manufactured by Toray Co., Ltd., volume average particle diameter: 5 mu m) were stirred to prepare a coating solution. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate having a thickness of 300 μm using MetaBa # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

(Comparative Example 5)

12.5 g of "HALS Hybrid" UV-G720T (acrylic copolymer, concentration 40% by mass, Nippon Shokubai Co., Ltd.), 336.9 g of ethyl acetate, nylon resin particles (SP20, Volume average particle diameter 30 mu m) and 35 g of nylon resin particles (SP500, manufactured by Toray Co., Ltd., volume average particle diameter: 5 mu m) were stirred to prepare a coating solution. This coating solution was applied to one side of a white film (base film, "Lumirror (registered trademark) E6SQ" manufactured by TORAY K.K.) containing porous biaxially oriented polyethylene terephthalate with a thickness of 300 μm using METABA # 20 And a coating layer was formed under drying conditions of 120 占 폚 for 1 minute.

The base film on which the coating layer obtained in each of the Examples and Comparative Examples was formed was evaluated as a reflective film. The application layer of the embodiment corresponds to a particle containing layer. In addition, even when the volume average particle diameter described in the examples is not in the range of 25 to 50 占 퐉 and 1 to 15 占 퐉, there is a particle size distribution in the particles. Therefore, particles having a particle diameter of 25 to 50 占 퐉, There are particles having a particle diameter of 1 to 15 mu m.

Table 1 shows the particle material, the ratio of the particles in the particle-containing layer, and the mass per square meter of the particle-containing layer.

In Table 2, SRz, the presence of particles having a particle diameter of 25 to 50 占 퐉, the presence of particles having a particle diameter of 1 to 15 占 퐉, the existence of independent existence without contact with convex portions having a diameter of 25 to 50 占 퐉, The number of convex portions having a diameter of 50 to 50 占 퐉 and the number of convex portions included in an aggregate of the convex portions with which the convex portions having a diameter of 25 to 50 占 m are continuously contacted is 10 or less.

Table 3 shows the dispersibility of the particles, the occurrence of scratches on the reflective film, the evaluation of the light guide plate cutting, and the results of the white point unevenness evaluation.

All of the reflective films of the examples having the features of the present invention were better than the reflective films of the comparative examples in the evaluation results of occurrence of the reflective film scratches.

1: Reflective film
2: light guide plate
3: Light emitting diode
4: Rear housing
5: convex portion of the light guide plate
6: concave portion of light guide plate
7: concave portion of back housing

Claims (4)

A base film and a particle containing layer containing particles having a particle diameter of 25 to 50 占 퐉 and particles having a particle diameter of 1 to 15 占 퐉,
Wherein at least one surface satisfies the following requirements (i) to (iii).
(i) convex portions having a diameter of 25 to 50 mu m.
(ii) the number of convex portions having diameters of 25 to 50 mu m is 10 to 100 per 0.64 mm &lt; 2 &gt; independently of the convex portions having diameters of 25 to 50 mu m.
(iii) The number of convex portions included in the aggregate of the convex portions continuously contacting the convex portions having a diameter of 25 to 50 占 퐉 is 10 or less per 0.64 mm2. The edge light type reflective film for backlight according to claim 1, wherein the face satisfying the requirements of (i) to (iii) is a face of the particle containing layer. The edge light type reflective film for a backlight according to claim 1 or 2, wherein the SRz of the surface satisfying the requirements (i) to (iii) is 15 to 60 占 퐉. An edge light type backlight using the edge light type back light reflecting film according to any one of claims 1 to 3.

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