JP2012079474A - Light emitting body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planar light emitting body for supplying light by using a light guide system, in which transparency can be secured by lowering a haze value in a thickness direction when a light source is turned off and a highly efficient light emission can be made possible by using a plate surface crossing radiant diverging light when the light source is turned on.SOLUTION: The planar light emitting body 2 in which a soft transparent base material containing light diffusion particles is used guides light in a length direction of the soft transparent base material while scattering the light in a thickness direction, and moreover, an operation value (m/%) obtained after dividing a brightness attenuation coefficient E(m) by a haze value per 5(mm) of the thickness of the soft transparent base material is 0.55(m/%) or more and 10.0(m/%) or less, and a tensile modulus of elasticity of the soft transparent base material at 25°C is 20-2,000 MPa.

Description

  The present invention relates to a light emitter that is supplied with light using a light guide method, and more particularly, to a light emitter using a soft transparent substrate.

Conventionally, surface light emitters have been mainly used as displays as seen in backlight light source devices of liquid crystal display devices.
In recent years, there has been an increase in the use of this surface emitting plate as a light shielding plate for building materials, amusements, and the like. In such a case, the light-shielding plate acts like a transparent plate when the light source is turned off, and acts as a light-shielding plate by means of radiation radiated across the plate surface (both front and back) when the light source is turned on. It is required to do. There is also a movement to use such a surface light emitter as a sign or a signboard surface light emitter.

  Conventionally, a general liquid crystal display device requires a non-transparent backlight device in the case of a transmissive liquid crystal, and a reflector is practically required in the case of a reflective liquid crystal. Therefore, in any case, the display device as a whole was not transparent.

  In a surface light emitter, as seen in a backlight light source device of a liquid crystal display device, a structure in which a scattering function is attached to the surface of a light guide plate by unevenness or dot printing (Patent Document 1), or refraction of a base material on the light guide plate A configuration (Patent Document 2) is known in which light diffusing particles having a small refractive index difference Δn between the refractive index and the refractive index of the light diffusing particles are internally added. In these configurations, the light guide plate is opaque when the light source is turned off, or the haze value in the thickness direction of the light guide plate is large. For this reason, it is possible to perform a light shielding effect when the light source is turned on, but it is difficult to act like a transparent plate when the light source is turned off.

In addition, such a light emitter is processed according to the application. However, if the light emitter itself is a hard material, the processing process may be damaged or the processing accuracy may be reduced, or the processing process may take time. Was. Specifically, if the illuminant is a hard material, in the processing step, for example, the surface of the planar molded product is subjected to printing pattern processing such as uneven processing by cutting or hot press transfer, screen printing, ink jet printing, and the like. After that, when bending or cutting so as to have a predetermined shape, there is a problem that the uneven portion is deformed by heat or the printed portion is peeled off. Also, if the material is hard, cracks or cracks may occur when it is washed with a solvent or detergent or used for a long time due to residual stress generated during bending or thermal processing or stress generated during warping correction during installation. There are problems such as cloudiness. In addition, the processability, design and safety of light-emitting devices equipped with light emitters are improved (hardly damaged, etc.), and the light emitters are continuously rolled to roll (rolled raw material material). Used to unwind the raw material from the roll, process it continuously, wind the processed material to the roll and send it to the next process.) Yes.
From the above viewpoint, a light emitting body having flexibility is required.

JP-A-57-128383 Japanese Patent No. 3162398

  The present invention has been made in view of such circumstances, and in a light-emitting body that supplies light using a light guide method (backlight method), the thickness direction or the thickness direction (light guide direction) when the light source is turned off. Transparency is ensured by lowering the haze value in the direction orthogonal to the light source, and light emission that enables high-efficiency light emission and flexibility by using cross-plane radiated divergent light when the light source is turned on The purpose is to provide a body.

In order to solve the above problems, one embodiment of a light emitter according to the present invention is a light emitter using a soft transparent substrate containing light diffusing particles. Further, the light emitter (1) guides light in the length direction of the soft transparent substrate while scattering light in the thickness direction of the soft transparent substrate, and (2) luminance attenuation coefficient E (m ⁻¹ ) is divided by the haze value (%) per 5 (mm) thickness of the soft transparent substrate, the calculated value (m ⁻¹ /%) is 0.55 (m ⁻¹ /%) or more. 0 (m ⁻¹ /%) or less, and (3) the tensile elastic modulus at 25 ° C. of the soft transparent substrate is 20 MPa to 2000 MPa. This illuminant works as a transparent plate by using a soft transparent substrate with a low haze value that satisfies the calculated value when turned off, and emits highly efficient light by light diffusing particles contained in the soft transparent substrate when turned on Is realized. Further, by using a soft transparent substrate, a light-emitting body having flexibility and good workability is realized. Thus, a display device that functions as a backlight or a light shielding plate is provided.

  The phosphor preferably has a concentration of the light diffusing particles of 0.0001 wt% or more and 2.0 wt% or less. Moreover, it is preferable that the said soft transparent base material is a light-guide plate whose haze value of the thickness direction is 30% or less. Further, the soft transparent substrate is an acrylic block copolymer or a composition containing an acrylic block copolymer, a thermoplastic polyurethane or a thermoplastic polyurethane composition, a fluorine acrylic resin, and a plasticizer acrylic resin composition. Is preferably selected from the group consisting of an acrylic block copolymer and an acrylic block copolymer. The shape of the light emitter may be a curved surface, a rod, a cylinder, a plane, or a wedge.

  According to one aspect of the illuminant of the present invention, when the light source is turned off, the thickness direction, or the haze value in the thickness direction is reduced to ensure transparency, and when the light source is turned on, by using cross-plane radiated divergent light, A light emitter that can emit light with high efficiency and has flexibility can be provided. In addition, a light emitter having a relatively simple structure can be easily processed later, and a light emitter having a more complicated structure can be easily obtained.

It is a figure which shows an example of the surface light-emitting body concerning Embodiment 1 of this invention. It is a figure which shows an example of the luminance distribution measuring system of the surface light-emitting body concerning Embodiment 1 of this invention. It is a figure which shows an example of the luminance distribution measurement result of the surface emitting body concerning Embodiment 1 of this invention. It is a figure which shows an example of the logarithm plot of the luminance distribution of the surface emitting body concerning Embodiment 1 of this invention. In the surface light emitter concerning Embodiment 1 of the present invention, it is a figure showing an example of relation between luminance value B (x) and light guide distance x (m) when luminance attenuation coefficient E differs. In the surface light emitter concerning Embodiment 1 of the present invention, it is a figure showing an example of relation between luminance value B (x) and light guide distance x (m) when luminance attenuation coefficient E differs. In the surface light emitter concerning Embodiment 1 of this invention, it is a figure explaining the relationship between the thickness (t) of a light-guide plate, and the density | concentration of a light-diffusion particle. In the surface light emitter concerning Embodiment 1 of this invention, it is a figure explaining the relationship between the thickness (3t) of a light-guide plate, and the density | concentration of a light-diffusion particle. It is a figure which shows the case of a rectangle as an example of the shape of the light-emitting body concerning Embodiment 2 of this invention. It is a figure which shows the case of a wing shape as an example of the shape of the light-emitting body concerning Embodiment 2 of this invention. It is a figure which shows the case of a flame shape as an example of the shape of the light-emitting body concerning Embodiment 2 of this invention. It is a figure which shows the case of the shape bent as an example of the shape of the light-emitting body concerning Embodiment 2 of this invention. It is a figure which shows the case where a prism shape is provided as an example of the shape of the light-emitting body concerning Embodiment 2 of this invention. In the surface light emitter concerning the Example of this invention, it is a figure which shows the relationship between the luminance attenuation coefficient E and the haze value per 5 mm thickness.

(Embodiment 1)
Hereinafter, a plate-like surface light emitter will be described as an example of a light emitter with respect to Embodiment 1 of the present invention with reference to the drawings. The surface light emitter according to Embodiment 1 of the present invention uses a light guide plate containing light diffusing particles. When light is supplied from the light source, the light guide plate guides light in the length direction of the light guide plate while scattering light in the thickness direction of the light guide plate. The length direction of the light guide plate is a direction from an end face (incident end face) that supplies light from the light source to an opposite end face, and is parallel to the direction in which the supplied light guide light goes straight. The thickness direction of the light guide plate is a direction indicating the thickness of the light guide plate, and is perpendicular to the length direction. The direction perpendicular to both the length direction of the light guide plate and the thickness direction of the light guide plate is defined as the width direction of the light guide plate. The light guide plate will be described using a plate shape. The light guide plate may have a shape (cross-sectional wedge shape) whose thickness changes in the length direction and the width direction.

  FIG. 1 shows an example of a surface light emitter. In FIG. 1, the light source 1 is disposed at the end of the surface light emitter 2. A reflection cover 6 for efficiently using light is disposed around the light source 1. In FIG. 1, the light source 1 is disposed on the left side of the surface light emitter 2, and the light is guided from the incident end surface of the surface light emitter 2 to the end surface facing the incident surface.

  Moreover, the arrow group shown on both sides of the surface light emitter 2 in FIG. 1 schematically shows how light diffuses. Light incident on the incident end surface of the surface light emitter 2 from the light source 1 is guided to the end surface opposite to the incident surface of the surface light emitter 2. Meanwhile, the light is diffused by the light diffusing particles and emitted from the front and back surfaces of the surface light emitter 2. The amount of emitted light decreases as the light guide distance increases.

Further, the light guide plate of the present embodiment is configured such that the haze value in the thickness direction of the light guide plate is 30% or less.
In addition, the light guide plate has a luminance calculated by dividing the luminance attenuation coefficient E (m ⁻¹ ) by the haze value (%) per 5 (mm) thickness in terms of luminance (m ⁻¹ /%) of 0.55 (m ⁻¹ /%) or more and 10.0 (m ⁻¹ /%) or less.
The calculated value indicates one characteristic relating to luminance, and serves as an index for defining a highly transparent light guide plate while realizing highly efficient light emission. Since the calculated value is calculated using the luminance attenuation coefficient E (m ⁻¹ ), the luminance attenuation coefficient E (m ⁻¹ ) will be described first.

The luminance attenuation coefficient E (m ⁻¹ ) in the present invention is a direction perpendicular to the light emitting surface in contact with the end surface when light is incident from the end surface from a light source disposed on one end surface of the surface light emitter. It means the gradient when the luminance characteristic is expressed by plotting the logarithm of the luminance value of the emitted light and the distance from the end face. The luminance attenuation coefficient E is expressed in units of (m ⁻¹ ) or (parts / m) because the result of measuring the luminance of a predetermined region (parts) in an arbitrary length unit (m) is used. Shall. In the following description, (m ⁻¹ ) is used for explanation.

The brightness measurement result theoretically follows the following formula (1). Here, the measured luminance value is represented by U (x), and the theoretical luminance value is represented by B (x).
B (x) = B (0) × exp (−E × x) (1)
Here, x (x ≧ 0) indicates a distance (light guide distance) from the incident end face.

The luminance attenuation coefficient E (m ⁻¹ ) is derived with attention to the following.
1. A material that absorbs light, such as a black cloth, is disposed on the back surface of the light guide plate. This is to absorb the light emitted to the back side for easy analysis. Here, the luminance measurement side is the front surface, and the opposite side is the back surface.

2. In the vicinity of the end surface facing the incident surface, the luminance characteristics may not follow the formula (1) due to the influence of light reflection from the end surface. Therefore, in order to eliminate this influence, the measurement is performed by applying an absorption process to the end face facing the incident surface. As an absorption processing method, for example, black ink is applied to an end surface facing the incident surface. In the case where a mirror is disposed on the end surface facing the incident surface, the absorption process is performed after the mirror is removed.

3. In the vicinity of the incident end face, the luminance characteristic may not follow the formula (1), so that portion is excluded when the luminance attenuation coefficient E (m ⁻¹ ) is derived. For example, the luminance attenuation coefficient E and the calculated value are derived from the end surface facing the incident surface in the direction of the incident end surface based on the luminance characteristics at L / 2 or L / 3. Here, L is the distance (m) from the light source light incident end face to the opposite end face. The reason why the luminance characteristics may not follow the formula (1) in the vicinity of the incident end face is not clear, but the addition amount of the light diffusing particles is small, and the refractive index difference Δn (the refractive index of the transparent substrate and the refractive index of the light diffusing particles). Therefore, the light diffusion angle distribution in the light guide plate in the vicinity of the incident end face has a light diffusion angle distribution of L / 2 or L / 3 in the direction of the incident end face. This is presumed to be due to the fact that it is different from the diffusion angle distribution, or due to the influence of the reflection of the light source on the reflection cover.

4). The luminance attenuation coefficient E (m ⁻¹ ) is a straight line in the range from the end surface facing the incident surface to L / 2 (center of the surface light emitter) or L / 3, using the luminance characteristic diagram shown in FIG. 4 to be described later. Derived by approximation.

  FIG. 2 shows an example of a luminance distribution measurement system for a surface light emitter. In FIG. 2, the light source 1, the surface light emitter 2, and the luminance meter 3 are provided. In addition, an absorption sheet 4 that absorbs light emitted to the back side is disposed on the back side of the surface light emitter 2. An absorption process 5 is applied to an end face of the surface light emitter 2 facing the incident surface. Further, a reflective cover 6 for efficiently using light is disposed around the light source 1. In FIG. 2, the light source 1 is disposed on the left side of the surface light emitter 2, and light is guided from the incident end surface of the surface light emitter to the end surface facing the incident surface. The position of the incident end face is set to 0 m, and an arbitrary distance to the end face facing the incident face is defined as a light guide distance. The luminance meter 3 uses, for example, a CCD (Charge Coupled Device) camera. In FIG. 2, the thickness of the surface light emitter 2 (light guide plate) is indicated by t.

FIG. 3 is a diagram in which an example of the measured luminance value U (x) (cd / m ² ) and the distance x (m) from the incident end face is plotted. FIG. 4 is a luminance characteristic diagram in which the logarithm ln (U (x)) of the luminance value U (x) (cd / m ² ) and the distance x (m) from the incident end face are plotted.
Here, the theoretical luminance value B (0) (cd / m ² ) is based on the above-described definition of the luminance value and the luminance attenuation coefficient and the luminance characteristic derivation method for calculating the luminance attenuation coefficient and deriving the luminance characteristic. When the approximate line obtained by linear approximation in the range from the end face facing the incident surface to L / 2 (center of the surface light emitter) is extended to x = 0 (m), the value crossing the vertical axis is ln (B (0)) is a virtual luminance value calculated.

Next, the relationship between the luminance attenuation coefficient E (m ⁻¹ ) and the luminance will be described. The larger the value of the luminance attenuation coefficient E (m ⁻¹ ), the more light can be extracted per unit length in the light guide direction.
5A and 5B show a relationship example between the luminance value B (x) and the light guide distance x (m) when the luminance attenuation coefficient E (m ⁻¹ ) is different.

The relationship example in FIG. 5A was obtained by measuring the luminance of a surface light emitter containing light diffusing particles in a base material, and one type was selected from titanium oxide, zinc oxide, barium sulfate, aluminum oxide, and polystyrene. Light diffusing particles having a particle diameter of 0.5 to 3 μm are added to 0.05 to 0.0005% by weight with respect to a surface light emitter having a thickness of 5 mm (reference example). 5A is a case where the light guide distance is 0.2 (m) in any luminance attenuation coefficient E. In the example of the relationship in FIG. 5B, a light diffusing particle is contained in 0.0001 wt% to 2.0 wt% in a 5 mm-thick surface light emitter made of a soft transparent substrate. In addition, the thing of FIG. 5B is a case where the light guide distance is set to 0.15 (m) for any luminance attenuation coefficient E (Example). At this time, the decrease in B (x) increases as the luminance attenuation coefficient E (m ⁻¹ ) increases. That is, as a result of extracting more light from the surface light emitter 2, it can be seen that the decrease in B (x) is large.
By emitting light with high efficiency, the surface light emitter 2 can function as a light shielding plate during lighting. High-efficiency light emission is realized by increasing the luminance attenuation coefficient E described above.

Here, the haze value is examined. When the haze value exceeds 30%, the transparency is lost. The haze is preferably 20% or less, particularly preferably 10% or less. Although there is no particular lower limit, in order to realize high luminance, the content is set to 0.1% or more in the sense that the case of a transparent plate without addition of light diffusing particles is not included. However, when highly efficient light emission can be realized, a light guide plate having a haze value of less than 0.1% can be used.
In the embodiment of the present invention, when the haze value is different in the surface of the surface light emitter 2, the haze value is evaluated at a place having the smallest haze value among the surfaces of the surface light emitter 2.

Next, calculation values relating to luminance will be described. As described above, the calculated value (m ⁻¹ /%) is a value obtained by dividing the luminance attenuation coefficient E (m ⁻¹ ) by the haze value (%) per 5 mm thickness. A calculation value (m ⁻¹ /%) smaller than 0.55 is suitable for a long light guide distance, but the light extraction efficiency is small, so that the brightness at the time of lighting is not sufficient.
When the calculated value (m ⁻¹ /%) is larger than 10.0, the light extraction efficiency is high, and thus the brightness at the time of lighting is sufficient, but the light guide distance is short and insufficient.
In the surface light emitter 2 according to the embodiment of the present invention, the concentration of the light diffusing particles may be constant in the thickness direction, for example, a multi-layer configuration including a light diffusing particle-containing layer and a transparent layer, or the light diffusing particle-containing concentration. It may be a multilayer structure composed of two or more different layers. Also in the case of a multilayer structure, the haze value per 5 mm thickness is obtained based on the measured haze value as described above.

When the average diameter of the light diffusing particles used in the embodiment of the present invention is small, there may be a change in color, such as coloring that may be caused by the Rayleigh scattering phenomenon. In addition, even when the refractive index difference Δn is small, there may be a change in color, such as coloring that may be caused by the Rayleigh scattering phenomenon. Specifically, the scattered light may be bluish in the vicinity of the light source and yellowish in the position away from the light source.
Therefore, in order to suppress coloring that is considered to be caused by the Rayleigh scattering phenomenon, the product of the average diameter (mm) of the light diffusing particles and the absolute value of the refractive index difference is preferably 0.0001 (mm) or more.

The plate thickness t (mm) of the surface light emitter 2 is preferably in the range of D / 2 ≦ t ≦ 20D with respect to the size D (mm) of the light source in the plate thickness direction.
The reason for this will be described with reference to FIGS. 6A and 6B. FIG. 6A shows a schematic diagram of a surface light emitter 2a composed of a light guide plate 21a having a light diffusion particle 22 concentration C (wt%) and a substrate thickness t (mm). FIG. 6B shows an example of a surface light emitter 2b composed of a light guide plate b having a concentration C (weight%) of the light diffusion particle 22 and a plate thickness of 3t (mm). The plate thickness of the light guide plate 21b is three times the plate thickness of the light guide plate 21a.

  Since the total amount of the light diffusing particles 22 contained in the light guide plate 21b is larger than the light diffusing particles 22 contained in the light guide plate 21a, the light emission intensity seems to be higher. However, in the surface light emitters 2a and 2b shown in FIGS. 6A and 6B, the guided light travels inside the surface light emitters 2a and 2b while repeating total reflection. For this reason, when the concentration of the light diffusing particles is the same, the probability that the guided light is diffused by the light diffusing particles is the same as in FIGS. 6A and 6B. For example, FIG. 6A shows a case where light is diffused by the light diffusion particles 22p, and FIG. 6B shows a case where light is diffused by the light diffusion particles 22q. Thus, the luminance of the light emitting surface is the same in FIGS. 6A and 6B.

  On the other hand, the plate thickness t of the surface light emitter 2a in FIG. 6A is smaller than the plate thickness 3t of the surface light emitter 2b in FIG. 6B. Accordingly, the surface light emitter of the present invention is preferably thin.

  However, when the plate thickness is smaller than the size of the light source, the ratio of the light incident on the end surface becomes small, so that the light use efficiency may be reduced. Therefore, the plate thickness t (mm) of the surface light emitter is preferably in the range of D / 2 ≦ t ≦ 20D with respect to the size D (mm) of the light source in the plate thickness direction. More preferably, it is in the range of D ≦ t ≦ 15D.

  If the light-emitting body of the present invention is used, it can have a form of a soft sheet, a film, or a soft rod, and the thickness is not particularly limited, but the thickness is preferably 0.01 mm or more and 20 mm or less, 0 .05 mm or more and 10 mm or less is more preferable, and 0.1 mm or more and 2 mm or less is more preferable. When the illuminant is thinner than the above range, a light source having a sufficient amount of light cannot be used and sufficient light emission cannot be obtained. When the light emitter is thicker than the above range, it becomes difficult to manufacture the light emitter itself by, for example, extrusion molding.

As described above, one aspect of the surface light emitter of Embodiment 1 according to the present invention is a surface light emitter using a light guide plate containing light diffusing particles, and scatters light in the thickness direction of the light guide plate. However, the light is guided in the length direction of the light guide plate, the haze value in the thickness direction of the light guide plate is 30% or less, and the luminance attenuation coefficient E (m ⁻¹ ) is set to 5 of the light guide plate. (Mm) The calculated value (m ^-1 /%) divided by the haze value (%) per thickness is 0.55 (m ^-1 /%) or more and 10.0 (m ^-1 /%) or less. This surface light emitter works as a transparent plate by using a light guide plate with a low haze value when turned off, and realizes high-efficiency light emission by light diffusing particles contained in the light guide plate when turned on. Can be realized.

  Moreover, the light-emitting body of this embodiment uses a soft transparent substrate having flexibility. Thus, the light emitter has flexibility. Here, the soft transparent substrate has a tensile elastic modulus at 25 ° C. of 20 MPa to 2000 MPa. More preferably, the tensile elastic modulus at 25 ° C. is 20 MPa or more and 1000 MPa or less. Among them, a material having a tensile elastic modulus at 25 ° C. of 20 MPa to 100 MPa is preferable in that the light emitter itself can be an elastic light emitter having adhesiveness.

  The soft transparent substrate is not particularly limited, and various transparent materials such as acrylic, polyester, cycloolefin, silicon, and polycarbonate can be used. Among these, in terms of ease of moldability and material cost, (1) an acrylic block copolymer or a composition containing an acrylic block copolymer, (2) a thermoplastic polyurethane or a thermoplastic polyurethane composition, (3) It is preferable to use a fluorine-based acrylic resin (fluorine-based optical acrylic film) or (4) a plasticizer-based acrylic resin composition, and use an acrylic block copolymer or a composition containing an acrylic block copolymer. Is more preferable.

(1) Acrylic block copolymer or a composition comprising an acrylic block copolymer An acrylic block copolymer that can be used as a soft transparent substrate is a methacrylic acid ester monomer or an acrylic acid ester monomer. A polymer block (A) having a glass transition temperature of 50 ° C. or higher and a polymer block having a glass transition temperature of 20 ° C. or lower, synthesized from a methacrylic acid ester monomer and an acrylate monomer. (B). Although the structure of these acrylic block copolymers is not particularly limited, (A)-(B) type diblock copolymer, (A)-(B)-(A) type triblock copolymer, (A )-(B)-(A)-(B) type tetrablock copolymer, ((A)-(B)) n-X type star block copolymer (n represents an integer of 1 or more), etc. Examples of these may be used, or one or more of these may be used. Among the acrylic block copolymers, (A)-(B) type diblock copolymers and (A)-(B)-(A) type triblock copolymers are preferable, and (A)- (B)-(A) type triblock copolymer is more preferred.
These acrylic block copolymers may be used alone or in combination with other materials to the extent that the transparency of the soft transparent substrate required in the present invention is not impaired. Examples of materials that can be blended with these acrylic block copolymers include acrylic resins, acrylonitrile-styrene copolymers, ethylene-vinyl acetate copolymers, polyvinyl chloride, polyvinylidene fluoride resins, and polylactic acid.
Such an acrylic block copolymer and a composition containing the acrylic block copolymer are excellent in melt processability, and the phosphor formed from the polymer or the composition has flexibility, light resistance, and transparency. Excellent in properties.

  Examples of the monomer used for the synthesis of the polymer block (A) include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, and methacrylic acid. Methacrylic acid esters such as cyclohexyl, isobornyl methacrylate, phenyl methacrylate, 2-hydroxyethyl methacrylate; acrylic acid such as tert-butyl acrylate, cyclohexyl acrylate, isobornyl acrylate, phenyl acrylate, 2-hydroxyethyl acrylate Examples include esters. The polymer block (A) may be synthesized from one of these methacrylic esters and acrylic esters, or may be synthesized from two or more.

  Among these, from the viewpoint of improving the transparency and heat resistance of the resulting phosphor, the monomers used for the synthesis of the polymer block (A) include methyl methacrylate, ethyl methacrylate, tert-butyl methacrylate, Preferred are amyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, phenyl methacrylate, 2-hydroxyethyl methacrylate, tert-butyl acrylate, cyclohexyl acrylate, isobornyl acrylate, phenyl acrylate, 2-hydroxyethyl acrylate, Among the above, methyl methacrylate, ethyl methacrylate, tert-butyl methacrylate, amyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, phenyl methacrylate and 2-hydride methacrylate One or more methacrylic acid esters selected from Kishiechiru is more preferable. More preferred is methyl methacrylate. The acrylic block copolymer may contain two or more polymer blocks (A). However, the monomers constituting the polymer blocks (A) may be the same or different. It may be.

  Examples of the monomer used for the synthesis of the polymer block (B) include n-propyl methacrylate, n-butyl methacrylate, amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, 2-methacrylic acid 2- Methacrylic acid esters such as ethylhexyl, pentadecyl methacrylate, dodecyl methacrylate, phenoxyethyl methacrylate, 2-methoxyethyl methacrylate; methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate , Isobutyl acrylate, sec-butyl acrylate, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, dodecyl acrylate, benzyl acrylate, Acrylic acid phenoxyethyl, acrylic acid esters such as 2-methoxyethyl acrylate. The polymer block (B) may be synthesized from one of these methacrylic acid esters and acrylic acid esters, or may be synthesized from two or more kinds. When the acrylic block copolymer contains two or more polymer blocks (B), the monomers constituting the polymer blocks (B) may be the same or different. Good.

  Among these, from the viewpoint of improving the transparency, flexibility, and cold resistance of the resulting phosphor, the monomers used for the synthesis of the polymer block (B) include methyl acrylate, ethyl acrylate, and isopropyl acrylate. Acrylic acid esters such as n-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, phenoxyethyl acrylate, and 2-methoxyethyl acrylate are preferred.

  As a monomer used for the synthesis of the polymer block (A) and the polymer block (B) as long as the characteristics of the acrylic block copolymer are not impaired, a methacrylic acid ester and an acrylic acid ester having a reactive group May be used. Examples of the methacrylic acid ester and acrylic acid ester having a reactive group include glycidyl methacrylate, allyl methacrylate, glycidyl acrylate, and allyl acrylate. When these are used, they are usually used in a small amount, and are preferably used in an amount of 40% by mass or less, more preferably 20% by mass or less, based on the total mass of monomers used for the synthesis of each polymer block. The

  In addition, as long as the properties of the acrylic block copolymer are not impaired, other monomers may be used in combination as necessary for the synthesis of the polymer block (A) and the polymer block (B). May be. Examples of other monomers include methacrylic acid, acrylic acid, styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, acrylonitrile, methacrylonitrile, ethylene, propylene, isobutene, and 1,3-butadiene. , Isoprene, octene, vinyl acetate, maleic anhydride, vinyl chloride, vinylidene chloride and the like. These monomers are usually used in a small amount, and are preferably used in an amount of 40% by mass or less, more preferably 20% by mass or less, based on the total mass of monomers used for the synthesis of each polymer block. The

The acrylic block copolymer may have other polymer blocks as needed in addition to the polymer block (A) and the polymer block (B).
Examples of other polymer blocks include methacrylic acid, acrylic acid, styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, acrylonitrile, methacrylonitrile, ethylene, propylene, isobutene, and 1,3-butadiene. , Polymer blocks or copolymer blocks synthesized from monomers such as isoprene, octene, vinyl acetate, maleic anhydride, vinyl chloride, vinylidene chloride, polyethylene terephthalate, polybutylene terephthalate, polylactic acid, polyurethane, polydimethylsiloxane A polymer block made of The polymer block also includes a hydrogenated polymer block synthesized from a monomer containing a diene monomer such as 1,3-butadiene and isoprene.

The glass transition temperature of the polymer block (A) and the polymer block (B) is determined based on the polymer block (A) and the weight of the polymer block (A) and the weight observed in the curve obtained by measuring the acrylic block copolymer by DSC (Differential Scanning Calorimetry). It is the extrapolation start temperature (Tgi) of the transition region of the combined block (B). As a specific measuring method, the method detailed in the item of the following Example is employ | adopted. Based on the curve obtained by the DSC measurement, the acrylic block copolymer requires a plurality of glass transition temperatures derived from the polymer block (A) and the polymer block (B). The glass transition temperature derived from the polymer block (A) and the polymer block (B) is the same as the glass transition temperature of the polymer having the same chemical structure (monomer composition, stereoregularity, etc.) as the respective polymer blocks. Therefore, it can be easily determined which polymer block these glass transition temperatures are derived from. The polymer having the same chemical structure as the polymer block (A) and the polymer block (B) is obtained by analyzing the acrylic block copolymer by ¹ H-NMR, ¹³ C-NMR, etc. It can be easily produced by obtaining the chemical structures such as the monomer composition and stereoregularity of the block (A) and the polymer block (B), and appropriately performing polymerization so that the chemical structures are reproduced.

  The molecular weight of the acrylic block copolymer is not particularly limited, but gel permeation chromatography (GPC) can be used from the viewpoints of the formability of the light emitter and the mechanical properties such as tensile breaking strength, compression set, and heat resistance. ) The weight average molecular weight in terms of polystyrene determined by measurement is preferably 10,000 to 500,000, and more preferably 20,000 to 300,000.

  Examples of the method for forming the light emitter include a melt extrusion molding method, a melt injection molding method, and a solution casting method.

  The molecular weight distribution of the acrylic block copolymer is not particularly limited, but the weight average molecular weight / number average molecular weight values are 1.01 to 2.20 from the viewpoints of the stickiness and transparency of the surface of the phosphor. It is preferable that it is 1.05-1.60. When the molecular weight distribution is larger than the above range, there may be a disadvantage that the high molecular weight is increased and the transparency is impaired, or the low molecular weight component is increased and the surface is easily stuck. In addition, when the molecular weight distribution is smaller than the above range, the composition ratio of the low molecular weight component that favorably affects the moldability and the high molecular weight component that favorably contributes to the mechanical properties becomes small. The characteristics may be impaired.

  The acrylic block copolymer may have a functional group such as a hydroxyl group, a carboxyl group, an acid anhydride group, an amino group, or a trimethoxysilyl group in the molecular chain or at the molecular chain end as necessary. .

  As a method for producing the acrylic block copolymer, a living polymerization method capable of highly controlling the molecular structure is preferable.

Living polymerization is a method of synthesizing a block copolymer by polymerizing monomers of a polymer block constituting the block copolymer and then polymerizing other monomers before the polymerization is deactivated or stopped. For example, a method of polymerizing an organic rare earth metal complex as a polymerization initiator (see JP 06-93060 A), a salt of an alkali metal or alkaline earth metal using an organic alkali metal compound as a polymerization initiator, and the like A method of anionic polymerization in the presence of a mineral salt (for example, see JP-A-07-25859), a method of anionic polymerization in the presence of an organoaluminum compound using an organic alkali metal compound as a polymerization initiator (for example, No. 11-335432), atom transfer radical polymerization method (ATRP) (for example, “Macromol. Chem. Phys.”, 20 0 years, 201 Volume, see p.1108~1114) and the like.
Among the above living polymerization methods, from the viewpoints of molecular weight control, side reaction suppression, cost, etc., an anionic polymerization method using an organic alkali metal compound as a polymerization initiator in the presence of an organic aluminum compound, an atom transfer radical polymerization method (ATRP). And a method of anionic polymerization using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound is particularly preferred.

(2) Thermoplastic polyurethane or thermoplastic polyurethane composition The thermoplastic polyurethane used for the soft transparent substrate is obtained by reacting a polymer polyol, an organic polyisocyanate, and a chain extender. The thermoplastic polyurethane composition is composed of a thermoplastic polyurethane composition mainly composed of thermoplastic polyurethane.

[Polymer polyol]
As the polymer polyol, a polymer polyol conventionally used in the production of polyurethane can be used. Examples of such polymer polyols include polyester polyols, polyether polyols, polycarbonate polyols, polyester polycarbonate polyols, polyolefin polyols, conjugated diene polymer polyols that may be hydrogenated, castor oil polyols, vinyl polymer polyols, and the like. These polymer polyols may be used alone or in combination of two or more. Among these, as the polymer polyol, one or more of polyester polyol, polyether polyol, and polycarbonate polyol are preferably used, and polyester polyol and / or polyether polyol are more preferably used. Alternatively, polyether diol is more preferably used.

  Examples of the polyester polyol include, for example, a polyester polyol obtained by directly esterifying or transesterifying a polyol component and a polycarboxylic acid component such as an ester-forming derivative such as a polycarboxylic acid, its ester or an anhydride, Examples thereof include polyester polyols obtained by ring-opening polymerization of lactone using a polyol as an initiator.

  As the polyol component used in the production of the polyester polyol, those generally used in the production of polyester can be used. For example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,4-butanediol, neo Pentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 2-methyl-1,8- Octanediol, 2,7-dimethyl-1,8-octanediol An aliphatic diol having 2 to 15 carbon atoms such as 1,9-nonanediol, 2-methyl-1,9-nonanediol, 2,8-dimethyl-1,9-nonanediol, 1,10-decanediol; 1 molecule such as alicyclic diol such as 1,4-cyclohexanediol, cyclohexanedimethanol, cyclooctanedimethanol, dimethylcyclooctanedimethanol; aromatic dihydric alcohol such as 1,4-bis (β-hydroxyethoxy) benzene Diols having two hydroxyl groups per unit; polyols having three or more hydroxyl groups per molecule such as trimethylolpropane, trimethylolethane, glycerin, 1,2,6-hexanetriol, pentaerythritol, diglycerin, etc. . In producing the polyester polyol, these polyols may be used alone or in combination of two or more. Among these, non-adhesive, excellent in melt moldability, transparency and flexibility, excellent in mechanical properties represented by tensile stress and tear strength, and becomes a thermoplastic polyurethane excellent in heat resistance, It is preferable to use an aliphatic diol having 4 to 10 carbon atoms such as 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, It is more preferable to use a linear aliphatic diol having 4 to 10 carbon atoms such as 4-butanediol, 1,6-hexanediol, and 1,8-octanediol.

  As the polycarboxylic acid component used in the production of the polyester polyol, those generally used in the production of polyester can be used. For example, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid , Sebacic acid, dodecanedioic acid, methylsuccinic acid, 2-methylglutaric acid, 3-methylglutaric acid, trimethyladipic acid, 2-methyloctanedioic acid, 3,8-dimethyldecanedioic acid, 3,7-dimethyldecanediate Aliphatic dicarboxylic acids having 4 to 12 carbon atoms such as acids; cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid, dimer acid and hydrogenated dimer acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid and naphthalenedicarboxylic acid Acid: Tri- or higher functional polycarbo such as trimellitic acid or pyromellitic acid Acid; or the like can be mentioned ester-forming derivatives thereof. These polycarboxylic acid components may be used alone or in combination of two or more. Among them, it is a thermoplastic polyurethane that is non-adhesive, excellent in melt moldability, transparency and flexibility, excellent in mechanical properties represented by tensile stress and tear strength, and excellent in heat resistance. 6-12 aliphatic dicarboxylic acids are preferred, adipic acid, azelaic acid and sebacic acid are more preferred, and adipic acid is even more preferred.

  Examples of the lactone used for producing the polyester polyol include ε-caprolactone and β-methyl-δ-valerolactone.

  Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (methyltetramethylene glycol) and the like obtained by ring-opening polymerization of a cyclic ether in the presence of a polyol. 1 type (s) or 2 or more types can be used. Among these, since it becomes a thermoplastic polyurethane that is non-adhesive, excellent in melt moldability, transparency and flexibility, excellent in mechanical properties represented by tensile stress and tear strength, and excellent in heat resistance, polytetra Methylene glycol and / or poly (methyl tetramethylene glycol) are preferably used.

  As said polycarbonate polyol, what is obtained by reaction of a polyol component and carbonate compounds, such as a dialkyl carbonate, an alkylene carbonate, a diaryl carbonate, is mentioned, for example. As the polyol component used for the production of the polycarbonate polyol, the polyol components exemplified above as the components that can be used for the production of the polyester polyol can be used. Examples of the dialkyl carbonate include dimethyl carbonate and diethyl carbonate. Examples of the alkylene carbonate include ethylene carbonate. Examples of the diaryl carbonate include diphenyl carbonate.

  As the above-mentioned polyester polycarbonate polyol, for example, those obtained by simultaneously reacting a polyol component, a polycarboxylic acid component and a carbonate compound, or previously synthesized polyester polyol and polycarbonate polyol, respectively, and then combining them with a carbonate compound. Examples thereof include those obtained by reacting or reacting with a polyol component and a polycarboxylic acid component.

  Specific examples of the polymer polyol include, for example, poly (1,4-tetramethylene adipate) diol, poly (3-methyl-1,5-pentamethylene adipate) diol, poly (ε-caprolactone) diol, poly Examples include tetramethylene glycol.

  The number average molecular weight of the polymer polyol is preferably in the range of 500 to 8,000, more preferably in the range of 600 to 5,000, and further in the range of 800 to 3,000. preferable. By using a polymer polyol having a number average molecular weight in this range, it is non-adhesive, excellent in melt moldability, transparency and flexibility, excellent in mechanical properties represented by tensile stress and tear strength, and heat resistant. In addition, an excellent thermoplastic polyurethane can be obtained. In addition, the number average molecular weight of the polymer polyol in the present specification is a number average molecular weight calculated based on the hydroxyl value measured according to JIS K 1557.

[Organic polyisocyanate]
As the organic polyisocyanate, organic polyisocyanates conventionally used in the production of polyurethane can be used. Examples of the organic polyisocyanate include 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, xylylene diisocyanate, 1,5-naphthylene diisocyanate, 3,3′-dichloro-4,4′-diphenylmethane diisocyanate. Aromatic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, and hydrogenated xylylene diisocyanate. These organic polyisocyanates may be used alone or in combination of two or more. Among them, it is non-adhesive, excellent in melt moldability, transparency and flexibility, excellent in mechanical properties represented by tensile stress and tear strength, and becomes a thermoplastic polyurethane excellent in heat resistance. It is preferably composed mainly of 4′-diphenylmethane diisocyanate (preferably containing 50 mol% or more, more preferably 80 mol% or more, still more preferably 95 mol% or more, particularly preferably 100 mol%).
Among the above organic polyisocyanates, aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, and hydrogenated xylylene diisocyanate are used from the viewpoint of light deterioration resistance of the light emitter. Is more preferable.

[Chain extender]
As the chain extender, a chain extender conventionally used in the production of polyurethane can be used. Examples of such chain extenders include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4-cyclohexanediol, bis Diols such as (β-hydroxyethyl) terephthalate and xylylene glycol; hydrazine, ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine, piperazine or derivatives thereof, phenylenediamine, tolylenediamine, xylenediamine, adipic acid dihydrazide, isophthal Diamines such as acid dihydrazide; and amino alcohols such as aminoethyl alcohol and aminopropyl alcohol. These chain extenders may be used alone or in combination of two or more. Among these, non-adhesive, excellent in melt moldability, transparency and flexibility, excellent in mechanical properties represented by tensile stress and tear strength, and becomes a thermoplastic polyurethane excellent in heat resistance, The chain extender mainly comprises an aliphatic diol having 2 to 10 carbon atoms (preferably 50 mol% or more, more preferably 80 mol% or more, further preferably 95 mol% or more, particularly preferably 100 mol%). More preferably, it is mainly composed of 1,4-butanediol (preferably containing 50 mol% or more, more preferably 80 mol% or more, further preferably 95 mol% or more, particularly preferably 100 mol%).

  In producing a thermoplastic polyurethane by reacting the above-mentioned polymer polyol, organic polyisocyanate and chain extender, the mixing ratio of each component is the hardness (flexibility) that should be imparted to the desired thermoplastic polyurethane, transparent The ratio is determined appropriately in consideration of the properties, mechanical performance, etc., but at a ratio such that the molar ratio of active hydrogen atoms: isocyanate groups present in the reaction system is within the range of 1: 0.9 to 1.1. It is preferable to use the components, and it is more preferable to use each component at a ratio of 1: 0.95 to 1.05. By using each component in the above proportion, it is non-adhesive, excellent in melt moldability, flexibility and transparency, excellent in mechanical properties represented by tensile stress and tear strength, and excellent in heat resistance. A thermoplastic polyurethane can be obtained.

  The method for producing the thermoplastic polyurethane is not particularly limited, and may be performed using any of the known urethanization reaction techniques using a polymer polyol, an organic polyisocyanate, and a chain extender. Any of the shot methods can be employed. Among these, it is preferable to perform melt polymerization substantially in the absence of a solvent, and it is more preferable to employ a continuous melt polymerization method using a multi-screw extruder. The polymerization temperature for melt polymerization is preferably in the range of 180 to 280 ° C.

  In obtaining the thermoplastic polyurethane by reacting the above-described polymer polyol, organic polyisocyanate and chain extender, a urethanization reaction catalyst may be used. The kind in particular of the said urethanation reaction catalyst is not restrict | limited, The urethanation reaction catalyst conventionally used for manufacture of a thermoplastic polyurethane can be used. Examples of the urethanization reaction catalyst include at least one compound selected from organic tin compounds, organic zinc compounds, organic bismuth compounds, organic titanium compounds, organic zirconium compounds, and amine compounds. . A urethanization reaction catalyst may be used individually by 1 type, or may use 2 or more types together.

  In the thermoplastic polyurethane, the content of nitrogen atoms derived from isocyanate groups is preferably 4.5% by mass or more. Thermoplastic polyurethane having a content of nitrogen atoms derived from isocyanate groups within the above range is non-adhesive, has excellent melt moldability, transparency and flexibility, and has mechanical properties represented by tensile stress and tear strength. Excellent and heat resistant. The content of the nitrogen atom derived from the isocyanate group in the thermoplastic polyurethane is more preferably 4.5 to 6.5% by mass, further preferably 4.6 to 6.0% by mass, and 4.7 to The amount is particularly preferably 5.7% by mass, and most preferably 4.8 to 5.5% by mass.

(3) Fluorine acrylic resin (acrylic film for fluorine optics)
The fluorine-based acrylic resin (fluorine-based optical acrylic film) used as the soft transparent substrate is composed of a resin composition (c) containing an acrylic polymer (a) and a fluorine-based resin (b).

  The acrylic polymer measured under the same conditions as described above, wherein light is incident from the end surface of the fluorine-based acrylic film made of the fluorine-based acrylic resin, and the luminance of the light emitted from the opposite end surface facing the end surface is L1. When the luminance of the film consisting only of a) is L2, the luminance ratio (L1 / L2) of these films is preferably greater than 1, more preferably 1.05 or more, and even more preferably 1.1 or more. As will be described later, the luminance ratio (L1 / L2) is obtained particularly in a film having a film thickness of 350 μm, a distance between the end face (I) and the end face (O) of 0 cm, and a rectangular planar shape. It is preferred that

[Acrylic polymer (a)]
The acrylic polymer (a) is a polymer comprising 50 to 100% by mass of alkyl methacrylate units having 1 to 4 carbon atoms in the alkyl group and 0 to 50% by mass of other vinyl monomer units copolymerizable therewith. Is preferred. The content of the alkyl methacrylate unit is preferably 50% by mass or more, more preferably 70% by mass or more, and further preferably 80% by mass or more from the viewpoint of obtaining desired properties of the acrylic polymer (a).

  Examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, butyl methacrylate, propyl methacrylate and the like.

  Here, “polymer” means a homopolymer or a copolymer. When the acrylic polymer (a) is a homopolymer, it is, for example, polymethyl methacrylate, and when the acrylic polymer (a) is a copolymer, for example, it is a copolymer of methyl methacrylate and a vinyl monomer other than methyl methacrylate.

  Examples of other vinyl monomers copolymerizable with the above alkyl methacrylate include alkyl acrylates having 1 to 8 carbon atoms in the alkyl group such as methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate, and 2-ethylhexyl acrylate. ; Alkyl methacrylate having 1 to 4 carbon atoms of alkyl group such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate (other than the above alkyl methacrylate); aromatic methacrylate such as phenyl methacrylate, benzyl methacrylate, isobornyl Alicyclic methacrylates such as methacrylates; Aromatic vinyl compounds such as styrene, α-methylstyrene, paramethylstyrene; Bis such as acrylonitrile and methacrylonitrile Lucian compounds and the like, may be used in combination of two or more of these.

  Among these, from the viewpoints of compatibility with the fluororesin (b), transparency of the resulting soft transparent substrate, heat resistance, and weather resistance, methyl methacrylate and alkyl acrylate having 1 to 8 carbon atoms in the alkyl group A copolymer of methyl methacrylate and methyl acrylate is more preferable. The composition of this copolymer is preferably 80 to 99% by mass of methyl methacrylate units and 1 to 20% by mass of alkyl acrylate units, 90 to 99% by mass of methyl methacrylate units, and 1 to 10% by mass of alkyl acrylate units. % Is more preferable.

  The weight average molecular weight (polystyrene conversion) of the acrylic polymer (a) is preferably in the range of 50,000 to 200,000. If the weight average molecular weight is too small, good mechanical strength cannot be obtained, and if it is too large, melt molding becomes difficult. The weight average molecular weight is more preferably 70,000 to 170,000, and further preferably 80,000 to 120,000.

[Fluorine resin (b)]
As the fluororesin (b), one having a sufficiently high compatibility with the acrylic polymer (a) is used. The compatibility between the fluororesin (b) and the acrylic polymer (a) is determined by measuring the glass transition point according to JIS K 7121 under the blending conditions of the film to be formed, and the acrylic polymer (a) and the fluororesin. It is preferable that the two glass transition points derived from (b) are not detected and only one glass transition point is detected.

  In addition, the fluororesin (b) has a melting peak derived from the crystal structure of the fluororesin (b) in the measurement of the melting temperature based on JISK7121 under the blending conditions of the acrylic polymer (a) and the film to be formed. It is preferable that no state is observed.

  As the fluororesin (b), trifluoroalkyl methacrylate homopolymer, tetrafluoroalkyl methacrylate homopolymer, pentafluoroalkyl methacrylate homopolymer, octafluoroalkyl methacrylate homopolymer, heptadecafluoroalkyl methacrylate homopolymer, Fluorinated alkyl methacrylate polymer such as fluorinated alkyl methacrylate / alkyl methacrylate copolymer; trifluoroalkyl α-fluoroacrylate homopolymer, tetrafluoroalkyl α-fluoroacrylate homopolymer, pentafluoroalkyl α-fluoroacrylate only Polymer, octafluoroalkyl α-fluoroacrylate homopolymer, heptadecafluoroalkyl αfluoroacrylate homopolymer, etc. Α-fluoromethacrylate polymers; vinylidene fluoride homopolymers, vinylidene fluoride / tetrafluoroethylene copolymers, vinylidene fluoride / hexafluoropropylene copolymers, and the like, and these A mixture of two or more of these may be used.

  Among these, a vinylidene fluoride polymer is preferable and a vinylidene fluoride homopolymer is more preferable from the viewpoint of transparency when blended with the acrylic polymer (a).

[Resin composition (c)]
The fluorine-based acrylic resin (fluorine-based optical acrylic film) used as the soft transparent substrate is composed of a resin composition (c) formed by blending the acrylic polymer (a) and the fluorine-based resin (b).

  As a blending method, a commonly used method can be used. Although it does not specifically limit, For example, the method of melt-kneading with a twin-screw extruder after mechanically mixing with mixers, such as a Henschel mixer, is mentioned.

  The mixing ratio (a / b, mass ratio) between the acrylic polymer (a) and the fluororesin (b) is preferably in the range of 30/70 to 99.9 / 0.1.

  From the point of obtaining a sufficient transparency improvement effect of the fluororesin (b), the blending ratio of the fluororesin (b) is 100 parts by mass in total of the acrylic polymer (a) and the fluororesin (b). On the other hand, it is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, further preferably 3 parts by mass or more, and particularly preferably 5 parts by mass or more. That is, the mixing ratio (a / b) is preferably 99.9 / 0.1 or less, more preferably 99/1 or less, still more preferably 97/3 or less, and particularly preferably 95/5 or less.

  If the amount of the fluorine-based resin (b) is too large, crystallization of the fluorine-based resin (b) is likely to occur, the resulting fluorine-based acrylic resin becomes cloudy and the light transmittance is likely to decrease.

  In general, the fluororesin (b) is slightly yellow, and as the amount of the fluororesin (b) added increases, the yellowness of the resulting fluoroacrylic resin tends to increase. Particularly for display applications, it is desired that the yellow color is small. Further, the glass transition temperature of the fluororesin (b) is lower than that of the acrylic polymer (a), and if the amount of the fluororesin (b) added is large, the heat resistance of the resulting fluoroacrylic resin is lowered. More generally, the fluororesin (b) is very expensive compared to the acrylic polymer (a), and the cost increases when the blending amount of the fluororesin (b) is increased. From these viewpoints, the blending ratio of the fluororesin (b) is preferably 70 parts by mass or less, more preferably 50 parts by mass or less, further preferably 35 parts by mass or less, particularly preferably 25 parts by mass or less, and 20 parts by mass. The following are most preferred. That is, the mixing ratio (a / b) is preferably 30/70 or more, more preferably 30/70 or more, further preferably 65/35 or more, particularly preferably 75/25 or more, and most preferably 80/20 or more.

  Considering the above matters, the mixing ratio of the acrylic polymer (a) and the fluororesin (b) is 30 to 99.9 masses when the acrylic polymer (a) is 100 mass parts. Part, fluororesin (b) 0.1-70 parts by weight is preferred, acrylic polymer (a) is 50-99 parts by weight, fluororesin (b) 1-50 parts by weight is more preferred, acrylic polymer ( a) 65-97 parts by mass, fluorine-based resin (b) 3-35 parts by mass are more preferable, acrylic polymer (a) 75-97 parts by mass, fluorine-based resin (b) 3-25 parts by mass are particularly preferable, The acrylic polymer (a) is most preferably 80 to 95 parts by mass and the fluororesin (b) is 5 to 20 parts by mass. That is, the mixing ratio (a / b) can be set to satisfy, for example, 80/20 ≦ a / b ≦ 95/5.

  The resin composition (c) preferably has an extrapolated glass transition start temperature measured in accordance with JIS K 7121 of 70 ° C. or higher, more preferably 80 ° C. or higher, from the viewpoint of heat resistance of the fluorine-based acrylic resin. .

(4) Plasticizer-based acrylic resin composition The plasticizer-based acrylic resin composition used in the soft transparent substrate of the present application is plasticized with an acrylic (co) polymer (d) containing 50% by mass or more of methyl methacrylate units. Contains agent (e). A plasticizer system containing a plasticizer (e) when the luminance of the 21 cm optical path length of an acrylic sheet or film made of the same material as the above acrylic resin composition is 100% except that the plasticizer (e) is not contained. The brightness of the sheet or film made of the acrylic resin composition is 90% or more, and the elongation at break is 10% or more.

[Acrylic (co) polymer (d)]
The acrylic (co) polymer (d) is a (co) polymer containing 50 parts by mass or more of methyl methacrylate units. Here, “(co) polymer” means a homopolymer or a copolymer. That is, when the acrylic (co) polymer (d) is a homopolymer, it is polymethyl methacrylate, and when it is a copolymer, it is a copolymer of methyl methacrylate and a monomer other than methyl methacrylate. . Specific examples of monomers other than methyl methacrylate include methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, phenyl (meth) acrylate, and (meth) acrylic. Examples include (meth) acrylic acid esters other than methyl methacrylate such as benzyl acid, 2-ethylhexyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate. Here, “(meth) acrylic acid ester” means acrylic acid ester or methacrylic acid ester.

  As the acrylic (co) polymer (d), a (co) polymer comprising 50 to 100% by mass of methyl methacrylate and 50 to 0% by mass of methyl acrylate is particularly preferable because of excellent light resistance.

[Plasticizer (e)]
The type and amount of the plasticizer (e) are not particularly limited, and may be appropriately selected so that the sheet or film made of the plasticizer acrylic resin composition exhibits the above-described specific luminance and specific breaking elongation. .

  The specific brightness in the present invention is as follows. First, an acrylic sheet or film comprising a plasticizer acrylic resin composition containing an acrylic (co) polymer (d) and a plasticizer (e), and the above acrylic except that the plasticizer (e) is not included. About the acrylic sheet or film which consists of the same thing as a resin composition, the brightness | luminance of 21 cm optical path length is measured on the same conditions. And the brightness | luminance of the sheet | seat or film which consists of a plasticizer type acrylic resin composition containing a plasticizer (e) is 90% or more on the basis of the brightness | luminance of the acrylic sheet or film which does not contain a plasticizer (e) It is necessary to become. It can be seen that the plasticizer (e) having this value of 90% or more has little light scattering and absorption, and is suitable for use as a light emitter. On the other hand, a plasticizer having this value of less than 90% has a large amount of light scattering and absorption, and is not suitable for light guide plate applications. In order to obtain higher luminance, this value is preferably 95% or more.

  The specific elongation at break in the present invention is as follows. For an acrylic sheet or film comprising a plasticizer acrylic resin composition containing an acrylic (co) polymer (d) and a plasticizer (e), the elongation at break is measured according to JIS K 7127. This breaking elongation is 10% or more, preferably 15% or more, more preferably 20% or more. If the elongation at break is within this range, in the manufacturing process of the illuminant, when the illuminant passes through each process, when slitting to a predetermined size, when cutting out, or when providing uneven shapes, the illuminant is cracked or chipped. Can be prevented well.

  The plasticizer (e) is used within a range showing the above luminance and breaking elongation. Preferable specific examples of the plasticizer (e) include phthalic acid plasticizers such as dibutyl phthalate and diisobutyl phthalate, and polyester plasticizers. The content of the plasticizer (e) is preferably 5 to 60% by mass, more preferably 11 to 30% by mass, based on the total of 100% by mass of the acrylic (co) polymer (d) and the plasticizer (e). Especially preferably, it is 13-25 mass%. The lower limit value of these ranges is significant in terms of improving the elongation at break. Further, the upper limit value is significant in terms of brightness improvement and prevention of bleeding out and heat resistance deterioration. In addition, it is particularly preferable to select a suitable type and content of the above-described plasticizer from the viewpoint of achieving both strength and luminance when the plasticizer acrylic resin composition is used as a light emitter.

[Thickness of acrylic sheet or film made of plasticizer acrylic resin composition]
When the plasticizer acrylic resin composition is used as an acrylic sheet or film, the thickness is preferably 2 mm or less, more preferably 0.05 to 2 mm, and still more preferably 0.05 to 1 mm. Even with such a thin acrylic sheet or film, the strength can be improved with almost no reduction in luminance. In addition, since the acrylic sheet or film thicker than the range mentioned above has sufficient intensity | strength, it is not necessary to add a plasticizer and improve intensity | strength.

[Method for producing acrylic sheet or film comprising plasticizer acrylic resin composition]
The acrylic sheet or film can be produced by, for example, a melt extrusion method using a T die or the like, a casting polymerization method, a solution casting method, or the like.

When an acrylic sheet or film made of a plasticizer acrylic resin composition is produced by a casting polymerization method, for example, a monomer containing 50 parts by mass or more of a methyl methacrylate unit and a plasticizer (e) are mixed and poured. The polymerization may be carried out, or the plasticizer (e) may be mixed into a syrup composed of this monomer and a polymer of this monomer and cast polymerization may be carried out. Examples of the initiator used for this polymerization include azo initiators and peroxide initiators. The syrup may be prepared by dissolving a polymer in a monomer, or may be prepared by partially polymerizing a monomer. Moreover, polyfunctional methacrylates and acrylates such as hexamethylene dimethacrylate, hexamethylene diacrylate, trimethylolpropane trimethacrylate, and trimethylolpropane triacrylate can be copolymerized and crosslinked.
The above cast polymerization method may be performed by a batch polymerization method or a continuous polymerization method.

  When producing an acrylic sheet or film made of a plasticizer acrylic resin composition by a melt extrusion method using a T-die or the like, for example, the water after emulsion polymerization is volatilized by spray drying (spray drying). The plasticizer (e) may be added to the finely particulate resin, or the plasticizer (e) may be directly injected from a feeder or the like during extrusion molding. Moreover, you may add a plasticizer (e) when carrying out suspension polymerization of the monomer containing 50 mass parts or more of methyl methacrylate units.

  Among these, it is preferable to add the plasticizer (e) at the time of suspension polymerization because the plasticizer volatilization during extrusion molding is small and the biting into the extrusion molding machine is good.

[Auxiliary]
An auxiliary agent can be added within a range that does not impair the luminance of the plasticizer acrylic resin composition. Specific examples of the auxiliary agent include lubricants, antibacterial agents, antifungal agents, light stabilizers, ultraviolet absorbers, bluing agents, antistatic agents, and heat stabilizers. The auxiliary agent can be preliminarily mixed with a mixer such as a Henschel mixer and pelletized with an extruder.

As described above, the light-emitting body of the present invention is characterized by being flexible because it uses the soft transparent substrate as described above. Thereby, since it can process in a roll state at the time of carrying out pattern processing of the light-emitting body surface, coating processing, and also at the time of adhesion processing or lamination processing, a processing process can be simplified greatly. Further, it is possible to prevent the light emitter from being cracked when punching the light emitter, and to easily obtain a high-quality light emitter.
Therefore, when various optical films are used in combination with the light emitter of the present invention, a function of eliminating a step generated by a frame or the like can be provided.

(Embodiment 2)
In Embodiment 1, a plate-like surface light emitter has been described as an example of a light emitter. In the second embodiment, a case of a light emitter having another shape will be described. An example of the light emitter of this embodiment will be described with reference to FIGS. 7A to 7D and FIG.

The shape of the surface light emitter which is one embodiment of the light emitter is, for example, as shown in FIG. 7A, the light emitter 7a such as a rectangle, the shape seen from the front is a polygon such as a square, trapezoid, triangle, The shape formed by curves, such as an ellipse, may be sufficient.
The surface light emitter may be a wing-like light emitter 7b (FIG. 7B), a flame-like light emitter 7c (FIG. 7C), or the like, or may have another shape formed by a curve and a straight line.

  Further, the surface light emitter is not limited to a flat plate shape as shown in FIGS. 7A to 7C, and may be bent as shown in FIG. 7D. In FIG. 7D, a dotted line is used to indicate a line parallel to the base of the incident end face, and the state where the shape is bent is easily understood. 7D shows a state in which the same shape as in FIG. 7A is bent, but other shapes such as FIGS. 7B and 7C may be bent. By using a soft transparent substrate, processing can be facilitated when a curved light emitter is manufactured. Moreover, machining accuracy can be improved by facilitating machining.

The curved light emitter of the present invention can be processed so as to have a curved structure from the beginning, or can be bent after manufacturing a flat light emitter in advance. For example, it is possible to easily obtain light emitters having various structures, such as a light emitter having a plurality of curves such as a wave shape, and a light emitter having a spherical surface such as a dome shape.
Further, the curved light emitter shown in FIG. 7D of the present invention can be installed by winding it around a cylindrical column surface. For example, like a poster, it can be rolled and carried and wound around a pillar surface.

  7A to 7D show a shape in which the plate thickness of the light emitter is constant, the thickness of the plate may not be constant. Further, the width of the plate may not be constant. For example, the surface light emitter may have a wedge shape whose thickness gradually decreases as the distance from the light source side increases. Like the polygon, circle, or ellipse described above, the light source 1 may not have the same width. However, the incident end face facing the light source 1 preferably has at least the same width as that of the light source 1 or a width wider than that in order to effectively use light.

Further, the light emitter is not limited to a surface light emitter. The light emitter may be rod-shaped. Examples of the shape of the rod-shaped light emitter include a columnar shape, a prismatic shape, a conical shape, and a pyramid shape. The thickness may not be constant. The rod-shaped light emitter need not be linear, and may be bent. Moreover, you may have various structures. When obtaining a bent rod-shaped light emitter, it can be formed into a bent rod shape from the beginning, but after forming into a straight line, it can be processed later to obtain a bent rod-shaped light emitter.
The rod-shaped light emitter of the present invention can easily obtain a light emitter having a complicated structure, for example, a structure shaped like a character.

Further, the light emitter may be cylindrical. Examples of the shape of the cylindrical light emitter include a cylindrical shape, a rectangular tube shape, a hollow conical shape, and a hollow pyramid shape. The cylindrical light emitter need not be linear and may be bent. Further, the cylindrical light emitter need not be linear, and may be bent. Moreover, you may have various structures. When obtaining a curved tubular light emitter, it is possible to form a bent tubular light source from the beginning, but after forming it in a straight line, it is also possible to obtain a bent tubular light emitter by processing it later. It is.
The cylindrical light-emitting body of the present invention can easily obtain a light-emitting body having a complicated structure, such as a structure in the shape of a character.

  Furthermore, the shape of the light emitter may include a prism shape on one surface of the light emitter, for example. An example is shown in FIG. Further, the shape is not limited to the prism shape, and another shape formed by, for example, a waveform, a curved surface, or a slope may be added to one surface of the light emitter. In any case, it is preferable that the surface of the illuminant is so smooth that light incident on the surface can cause total reflection.

  Next, the relationship between the kind of the light diffusing particle of this embodiment and the luminance will be described. Also in this embodiment, the luminance can be measured using the luminance measurement system of FIG. However, the haze value can be measured for a shape including a flat portion such as the light emitters 7a to 7d, but is measured when there is no flat portion such as the light emitter 7e. I can't. In such a case, it is also possible to form and measure a flat light emitter by using the same soft transparent base material and light diffusing particles constituting the light emitter. Therefore, in this embodiment, the relationship between the type of light diffusing particles and the luminance is examined.

The luminance (cd / m ⁻² ) is measured with attention to the following.
1. A material that absorbs light, such as a black cloth, is disposed on the back surface of the light guide plate as the absorbent sheet 4. This is because the light emitted to the back side is absorbed and only the light emitted from the front side is measured. Here, the luminance measurement side is the front surface, and the opposite side is the back surface.

2. In the vicinity of the end surface facing the incident surface, the luminance characteristics may change due to the influence of light reflection from the end surface. Therefore, in order to eliminate this influence, the measurement is performed by applying an absorption process 5 to the end face facing the incident surface. As an absorption processing method, for example, black ink is applied to an end surface facing the incident surface.

  Using the example of the relationship between the luminance value B (x) of the surface light emitter and the light guide distance x (m) in the case where the type and concentration of the light diffusing particle are different as shown in FIG. Consider the relationship with brightness.

  The relationship example in FIG. 5A is a measurement of the luminance of a surface light emitter in which light diffusing particles are added to a base material. Light selected from one of titanium oxide, zinc oxide, barium sulfate, aluminum oxide, and polystyrene. Light diffusion particles having a diffusion particle diameter of 0.5 to 3 μm are added to 0.02 to 0.0005% by weight with respect to a surface light emitter having a thickness of 5 mm. In either example, the light guide distance is 0.2 (m). At this time, it can be seen that the luminance characteristics vary greatly depending on the type and concentration of the light diffusing particles.

  As a result of various examinations of light emitters having different types and concentrations of light diffusing particles, the present inventors found that the difference between the refractive index of the transparent substrate and the refractive index of the light diffusing particles (refractive index difference Δn) is within a specific range. The present inventors have found that a luminous body containing light diffusing particles having a concentration in a specific range has an excellent balance between the transparency when turned off and the luminance when turned on. Similarly, in the case where the substrate is a soft transparent substrate, it is predicted that a phosphor having a refractive index difference in a specific range and containing light diffusing particles in a specific range of concentration is also excellent in balance.

The refractive index difference Δn is preferably 0.3 or more. When the refractive index difference Δn is smaller than 0.3, light cannot be extracted efficiently, and the transparency is inferior to the brightness at the time of lighting. Moreover, it is preferable that it is 0.4 or more.
On the other hand, if the refractive index difference Δn is greater than 3, the scattered light is dominated by backscattering, so that the transparency is inferior to the brightness at the time of lighting.

  Furthermore, the light diffusing particles contained in the luminescent material of the present invention include various metal compounds and resins that are added later to the soft transparent substrate, and various additives that are added in the production of the soft transparent substrate. In addition, those having a light diffusion effect are also included. Examples of the various additives include polymerization initiators, catalysts, antioxidants, ultraviolet absorbers, and release agents.

  In other words, not only by adding appropriate light diffusing particles to the soft transparent substrate later, but also by making the type of the soft transparent substrate and the types of various additives used in its production appropriate, can do. For example, when an acrylic block copolymer that is preferably used as the substrate of the phosphor of the present invention is polymerized in the presence of an organoaluminum compound, the compound derived from the organoaluminum compound serves as a light diffusing particle. And a light emitter. Since the organoaluminum compound used here is often treated with an organic acid after polymerization, the compound derived from the organoaluminum compound that serves as the light diffusing particles is considered to be mainly the organic acid aluminum.

Also, when adding a suitable light diffusing particles into soft transparent substrate later, as the light diffusing particles, E a (m ^-1), the 5 (mm) Haze value per thickness of the soft transparent substrate ( As long as the calculated value (m ^-1 /%) divided by%) satisfies the requirement of 0.55 (m ^-1 /%) to 10.0 (m ^-1 /%), various Although a metal compound, resin, etc. can be used, for example, titanium oxide, zinc oxide and the like are preferable.

When the average diameter of the light diffusing particles used in the embodiment of the present invention is small, there may be a change in color, such as coloring that may be caused by the Rayleigh scattering phenomenon. In addition, even when the refractive index difference Δn is small, there may be a change in color, such as coloring that may be caused by the Rayleigh scattering phenomenon. Specifically, the scattered light may be bluish in the vicinity of the light source and yellowish in the position away from the light source.
Therefore, in order to suppress coloring that is considered to be caused by the Rayleigh scattering phenomenon, the product of the average diameter (mm) of the light diffusing particles and the absolute value of the refractive index difference is preferably 0.0001 (mm) or more.

  Further, the concentration of the light diffusing particles is preferably 0.0001 wt% or more and 2.0 wt% or less, more preferably 0.01 wt% or more and 1.5 wt% or less, and 0.02 wt% or more and 1 wt% or less. 0.0 wt% or less is more preferable, and 0.1 wt% or more and 0.5 wt% or less is particularly preferable. As the concentration of gravimetric light diffusing particles increases, the transparency of the light emitter decreases. For this reason, in order to maintain the transparency of the illuminant, for example, a low haze value if it is a plate-like illuminant, and a visually transparent feeling if it is not a plate-like substance, the concentration of the light diffusing particles should be kept low. Necessary. On the other hand, if the concentration of the light diffusing particles is too low, the light cannot be sufficiently scattered, and the luminance of the light emitter may be too low.

(Other embodiments)
The shape of the light source used in the present invention can be arbitrarily selected according to the shape of the incident end face and the design at the time of light emission.

(Reference Examples 1-3, Example 1, Comparative Example 1)
Reference Examples 1 to 3, Example 1, and Comparative Example 1 are shown below. The surface light emitter was produced using an injection molding machine. <Common conditions> in Reference Examples, Examples and Comparative Examples and <Conditions of Example 1> used in Example 1 are shown below.

<Common conditions>
Light source used (Reference Examples 1 to 3, Example 1 and Comparative Example 1)
Light source: “LED NFSW036BT” manufactured by Nichia Corporation
Use number: 7 Arrangement interval: 10mm
Applied voltage: 2.8 V / 1 light source Size of one light source: 3 mm (light emitting part)
Base resin, Reference Examples 1 to 3, Comparative Example 1; PMMA (acrylic resin) (“Parapet” manufactured by Kuraray Co., Ltd.), refractive index: 1.494 (nD),
Example 1; acrylic block copolymer (described later), refractive index 1.474
Sample size / Reference Examples 1 to 3, Comparative Example 1; 5 mm thickness × light guide length 200 mm × width 70 mm,
Example 1; 5 mm thickness x light guide length 150 mm x width 70 mm
Luminance measurement Distance between sample and luminance meter 5m, measurement size 8mm x 8mm

Table 1 shows the material configurations and measurement results of the light diffusing particles of the reference example and the comparative example. Further, FIG. 9 shows the relationship between the luminance attenuation coefficient E (m ⁻¹ ) and the haze value per 5 mm thickness. The haze value on the horizontal axis is the haze value per 5 mm thickness as described above. From the measurement results shown in FIG. 9, the following relational expression was derived when the haze value (%) was x and the luminance attenuation coefficient E (m ⁻¹ ) was y.
Titanium oxide y = 1.4797x
Zinc oxide y = 0.7726x
Aluminum oxide y = 0.3662x
Styrene y = 0.144x
In this relational expression, the coefficient of x corresponds to the calculated value (m ⁻¹ /%).
The tensile modulus of elasticity of PMMA (measured by a method described later) was 3200 MPa.

<Conditions of Example 1>
The acrylic block copolymer used as the base resin in Example 1 will be described.
Various physical properties of the acrylic block copolymer were measured or evaluated and synthesized by the following methods.

(1) Weight average molecular weight (Mw)
The weight average molecular weight (Mw) of the acrylic block copolymer and acrylic resin was determined by gel permeation chromatography (hereinafter abbreviated as GPC) in terms of polystyrene equivalent molecular weight.
-Equipment: GPC equipment "HLC-8020" manufactured by Tosoh Corporation
Separation column: “TSKgel GMHXL”, “G4000HXL” and “G5000HXL” manufactured by Tosoh Corporation are connected in series. Eluent: Tetrahydrofuran Eluent flow rate: 1.0 ml / min Column temperature: 40 ° C.
・ Detection method: Differential refractive index (RI)

(2) Composition ratio of each polymer block The composition ratio of each polymer block in the acrylic polymer block was determined by 1H-NMR (1H-nuclear magnetic resonance) measurement.
・ Device: JEOL Nuclear Magnetic Resonance Device “JNM-LA400”
・ Deuterated solvent: Deuterated chloroform

(3) Content of aluminum component in polymer About 5 g of the polymer obtained in the following examples was collected and weighed accurately, and placed in a volumetric flask having a capacity of 100 ml. 10 ml of concentrated sulfuric acid was added thereto, and the mixture was treated (wet decomposition) for about 2 hours at 250 to 300 ° C. Subsequently, 5 ml of concentrated nitric acid was added to this solution, and the treatment (wet decomposition) for about 2 hours at 250 to 300 ° C. was performed twice in total until the color of the solution became light yellow or colorless and transparent. Further, 5 ml of perchloric acid was added to this solution and treated (wet decomposition) for about 2 hours at 200 to 250 ° C. Thereafter, the volumetric flask was cooled to room temperature, distilled water was added, and the volume of the solution was accurately adjusted to 100 ml.
Using this solution as a sample, the content of the aluminum component was measured using an ICP emission spectroscopic analyzer (“IRIS / IRISAP” manufactured by Nippon Jarrell Ash Co., Ltd., using argon plasma) (aluminum wavelength = 396.152 nm).

(4) Tensile elastic modulus Using a composition containing the PMMA used in the reference example or the comparative example and the acrylic block copolymer obtained in the example, a 1 mm thick molded at a predetermined temperature by a press molding machine A test piece was prepared, the tensile dynamic viscoelasticity was measured, and the value of the elastic modulus (E ′) at 25 ° C. was measured.
・ Device: Wide-area dynamic viscoelasticity measuring device
"PVE-V4 FT Rheospectr" manufactured by Rheology Co., Ltd.
・ Measurement frequency: 11Hz
・ Measurement mode: Pull ・ Measurement temperature: 25 ℃
-Strain: 0.03%
Sample shape: strip shape (press sheet) of length 20mm x width 5mm x thickness 1mm

(5) Synthesis of acrylic block copolymer The acrylic block copolymer used in Example 1 was synthesized by the methods of Synthesis Examples 1 and 2 below.
In the synthesis examples shown below, the compound was dried and purified by a conventional method and degassed with nitrogen. Moreover, the transfer and supply of the compounds were performed in a nitrogen atmosphere.

[Organic Aluminum Compound: Preparation of Isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum]
After drying with sodium, 25 ml of dry toluene obtained by distillation under an argon atmosphere and 11 g of 2,6-di-t-butyl-4-methylphenol were placed in a 200 ml flask whose internal atmosphere was replaced with argon. Added and dissolved with stirring at room temperature. To the obtained solution, 6.8 ml of triisobutylaluminum was added and stirred at 80 ° C. for about 18 hours, whereby the corresponding organoaluminum compound [isobutylbis (2,6-di-t-butyl-4-methylphenoxy)] was obtained. A toluene solution containing [aluminum] at a concentration of 0.6 mol / l was prepared.

[Synthesis Example 1] [Synthesis of acrylic block copolymer]
A two-liter three-necked flask was fitted with a three-way cock, and the inside was deaerated and replaced with nitrogen. Then, at room temperature, 1040 g of dry toluene, 100 g of 1,2-dimethoxyethane, and isobutylbis (2,6-di-) of an organoaluminum compound. 48 g of a toluene solution containing 32 mmol of (t-butyl-4-methylphenoxy) aluminum was added, and 8.1 mmol of sec-butyllithium was further added. To this, 72 g of methyl methacrylate was added and reacted at room temperature for 1 hour, and then 0.1 g of the reaction solution was collected. This is designated as sampling sample 1. Subsequently, the internal temperature of the polymerization solution was cooled to −25 ° C., and 307 g of n-butyl acrylate was added dropwise over 2 hours. After completion of dropping, 0.1 g of the reaction solution was collected. This is designated as sampling sample 2. Subsequently, 72 g of methyl methacrylate was added, and the reaction solution was returned to room temperature and stirred for 8 hours. The polymerization was stopped by adding 50 g of 30% aqueous acetic acid to the reaction solution. The precipitate was removed with the centrifugal separator after the polymerization was stopped, and the resulting supernatant was poured into a large amount of methanol to obtain a deposited precipitate. This is designated as sampling sample 3. 1H NMR measurement and GPC measurement were performed using sampling samples 1 to 3, and based on the results, Mw (weight average molecular weight), Mw / Mn (molecular weight distribution), methyl methacrylate polymer (PMMA) block and acrylic acid n -When the mass ratio of the butyl polymer (PnBA) block was determined, the finally obtained precipitate was a PMMA block-PnBA block-PMMA block triblock copolymer (PMMA-b-PnBA-b). -PMMA), the Mw of the PMMA block portion is 9,900, Mw / Mn is 1.08, and the Mw of the entire triblock copolymer is 62,000, and Mw / Mn is 1.19. The ratio of each polymer block was PMMA (16 mass%)-PnBA (68 mass%)-PMMA (16 mass%).
When the metal content of the obtained triblock copolymer was measured, the amount of aluminum metal was 0.0023 wt%, and the compound derived from the organoaluminum compound (presumed to be aluminum acetate) was 0 in the triblock copolymer. 017% by weight (= 204.11 / 26.98 * 0.0023) was found to be contained.
Moreover, the tensile elastic modulus of this sample was 35 MPa.

[Synthesis Example 2]
The triblock copolymer obtained in Synthesis Example 1 was dissolved in toluene, and an organoaluminum compound isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum in toluene solution and acetic acid water were added thereto. The added solution was poured into a large amount of methanol to obtain a deposited precipitate.
When the metal content of the obtained triblock copolymer was measured, the amount of aluminum metal was 0.020% by weight, and the compound derived from the organoaluminum compound (presumed to be aluminum acetate) was 0 in the triblock copolymer. 15% by weight (= 204.11 / 26.98 * 0.020) was found to be contained.
Moreover, the tensile elastic modulus of this sample was 41 MPa.

In Example 1, a surface light emitter was manufactured using the triblock copolymers of Synthesis Examples 1 and 2.
Table 1 shows the material configurations and measurement results of the light diffusing particles of Synthesis Examples 1 and 2. In Synthesis Examples 1 and 2, a compound derived from an organoaluminum compound (presumed to be aluminum acetate) contained in the acrylic block copolymer functions as light diffusing particles. The haze value of Synthesis Example 1 is 2.9%, and the haze value of Synthesis Example 2 is 18.9%. Further, FIG. 9 shows the relationship between the luminance attenuation coefficient E (m ⁻¹ ) and the haze value per 5 mm thickness. The haze value on the horizontal axis is the haze value per 5 mm thickness as described above. From the measurement results shown in FIG. 9, the following relational expression was derived when the haze value (%) was x and the luminance attenuation coefficient E (m ⁻¹ ) was y.
A-B-A type triblock copolymer y = 0.6362x
In this relational expression, the coefficient of x corresponds to the calculated value (m ⁻¹ /%).

In FIG. 9, the range where the calculated value is 0.55 (m ⁻¹ /%) or more and 10.0 (m ⁻¹ /%) or less is indicated by two broken lines. The broken line on the left is y = 0.55x, and the broken line on the right is y = 10.0x.
In Reference Example 1, the calculated value was about 1.48 (m ⁻¹ /%), and the haze value was 1.0 to 5.0%.
In Reference Example 2, the calculated value was about 0.77 (m ⁻¹ /%), and the haze value was 3.1 to 8.6%.
In Example 1, the calculated value was about 0.64 (m ⁻¹ /%), and the haze value was 2.9 to 18.9%.
In Reference Example 3, the calculated value was about 0.37 (m ⁻¹ /%), and the haze value was 3.0 to 13.3%.
In Comparative Example 1, the calculated value was about 0.14 (m ⁻¹ /%), and the haze value was 4.1 to 25.3%.

<Evaluation>
With respect to the surface light emitters of these Examples, Reference Examples, and Comparative Examples, the transparency at the time of extinction and the brightness at the time of lighting were evaluated by five levels by visual evaluation. The most excellent one was 5, and the most inferior one was 1. In this evaluation, 3 or more was particularly good. The results are summarized in Table 2. As shown in Table 2, the surface light emitters of the examples were excellent in transparency and bright. On the other hand, the surface light emitter of the comparative example was inferior in transparency or dark. Moreover, in Example 1, it is thought that the organoaluminum compound (it is estimated that it is aluminum acetate) derived from the polymerization initiator system at the time of manufacture of an acryl-type block copolymer is functioning as a light-diffusion particle.

(Example 2, comparative example 2)
Example 2 and Comparative Example 2 were prepared in which the sample size was a cylindrical shape with a diameter of 10 mm and a length of 200 mm, and the number of light sources used was one. In Example 2, the acrylic block copolymer of Synthesis Example 2 of Example 1 was used as the base resin. In Comparative Example 2, the base resin added with the light diffusion particles of Comparative Example 1 described above was used.

  With respect to the rod-like light emitters of Example 2 and Comparative Example 2, the transparency when turned off and the brightness when turned on were visually evaluated. As a result, the luminescent material of Example 2 was excellent in transparency and bright. On the other hand, the luminous body of Comparative Example 2 was inferior in transparency or dark.

  As described above, according to the light guide type surface light emitter of the present invention, it is possible to realize a display device that has a high transparency when turned off and is bright when turned on and functions as a backlight or a light shielding plate. For example, an amusement decoration can be realized.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Light source 2, 2a, 2b Surface light-emitting body 3 Luminometer 4 Absorption sheet 5 Absorption processing 6 Reflective cover 21a, 21b Light guide plate 22, 22p, 22q Light-diffusion particle 7a-7e Light-emitting body

Claims (7)

A light emitter using a soft transparent substrate containing light diffusing particles, wherein light is guided in the length direction of the soft transparent substrate while scattering light in the thickness direction of the soft transparent substrate, and A calculated value (m ⁻¹ /%) obtained by dividing the luminance attenuation coefficient E (m ⁻¹ ) by the haze value (%) per 5 (mm) thickness of the soft transparent substrate is 0.55 (m ⁻¹ ). /%) And 10.0 (m ⁻¹ /%) or less, and the light emitting body having a tensile elastic modulus at 25 ° C. of the soft transparent substrate of 20 MPa to 2000 MPa.   The light-emitting body according to claim 1, wherein the concentration of the light diffusing particles is 0.0001 wt% or more and 2.0 wt% or less.   The light emitter according to claim 1 or 2, wherein the soft transparent substrate is a light guide plate having a haze value of 30% or less in the thickness direction.   The soft transparent substrate is selected from an acrylic block copolymer or a composition containing an acrylic block copolymer, a thermoplastic polyurethane or a thermoplastic polyurethane composition, a fluorine acrylic resin, and a plasticizer acrylic resin composition. The light-emitting body according to claim 1, wherein   The light-emitting body according to claim 4, wherein the soft transparent substrate is made of an acrylic block copolymer or a composition containing an acrylic block copolymer.   The illuminant according to claim 1, wherein the illuminant has a curved shape.   The light emitter according to claim 1, wherein the light emitter has a rod shape.

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