WO2019208771A1

WO2019208771A1 - Light diffusing formed body and transparent screen film

Info

Publication number: WO2019208771A1
Application number: PCT/JP2019/017944
Authority: WO
Inventors: 渉赤塚; 掛谷　文彰
Original assignee: 三菱瓦斯化学株式会社
Priority date: 2018-04-27
Filing date: 2019-04-26
Publication date: 2019-10-31
Also published as: CN112005133B; CN112005133A; JPWO2019208771A1

Abstract

The present invention provides a light diffusing formed body and a transparent screen film for which characteristics such as the transparency and viewing angle are satisfactory and that have particularly exceptional color reproducibility. To that end, a light diffusing formed body according to the present invention is made to include a transparent resin binder and light-diffusing particles and to have a ratio (A)/(B) of the average haze (A) for 380 to 480 nm to the average haze (B) for 380 to 780 nm as measured using a method conforming to JIS-K-7361 and JIS-K-7136 of 0.8 to 1.6, inclusive.

Description

Light diffusion molded body and transparent screen film

The present invention relates to a light diffusion molded article, for example, a light diffusion molded article suitable for a transparent screen for projecting and displaying an image, and a transparent screen film.

Conventionally, for example, transparent screens for displaying images for product advertisements are known (for example, Patent Documents 1 and 2). As such a transparent screen, a thin resin layer to which fine particles are added is employed, and an image projected from the projector is displayed on the transparent screen.

Japanese Patent No. 5752834 WO2016 / 0931181

In the case of a transparent screen, it is necessary to reach a practical level in terms of performance such as transparency and viewing angle.

However, many of the light diffusion molded articles used in conventional transparent screens cannot be said to have sufficient performance. For example, when a light diffusion molded body is used as a transparent screen that displays a moving image or a still image, the visibility of the projected image may not always be good.

More specifically, in a video projected on a transparent screen based on certain specific video data, a specific color, for example, blue is emphasized compared to a video displayed on another display device based on the same video data. Such a problem of color reproducibility sometimes occurs. For example, the transparent screen film disclosed in Patent Document 1 has a problem that the blue color of an image projected from a projector is emphasized.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have excellent performance such as transparency and viewing angle, as well as good color reproducibility and video visibility. It has been found that a high transparent screen film and a light diffusion molded article suitable for the production of such a transparent screen film can be realized, and the present invention has been completed.
That is, a light diffusion molded product and a transparent screen film that can achieve the above-described excellent characteristics were realized.
The present invention relates to a light diffusion molded article and a transparent screen film described below.
In the present specification, the film includes, for example, a sheet having a thickness of 1 mm or more.

(1) A light diffusion molded article containing a transparent resin binder and light diffusion particles,
Ratio (A) / (B) of average haze (A) of 380 nm to 480 nm and average haze (B) of 380 nm to 780 nm measured by a method according to JIS-K-7361 and JIS-K-7136 ) Is a light diffusion molded article having a value of 0.8 to 1.6.
(2) The value of H (Z) / H (Y), which is the ratio of H (Z) and H (Y) calculated by the following formulas (I) and (II), is 0. The light diffusion molded article according to the above (1), which is in the range of 8 to 1.5.
H (Y) = τd (Y) / τt (Y) (I)
H (Z) = τd (Z) / τt (Z) (II)
However, the values of τt (Y) and τt (Z) in the above formula are measured in a measurement wavelength range of 380 nm to 780 nm by a method in accordance with JIS-K-7361 and JIS-K-7136. Tristimulus values in the XYZ display system calculated by a method based on JIS-Z-8722 based on the value of total light transmittance (τt),
The values of τd (Y) and τd (Z) in the above formula are diffused light measured in a measurement wavelength range of 380 nm to 780 nm by a method based on JIS-K-7361 and JIS-K-7136. Tristimulus values in the XYZ display system calculated by a method based on JIS-Z-8722 based on the value of transmittance (τd).
(3) The light diffusion molded article according to (1) or (2) above, wherein the haze value measured by a method according to JIS-K-7361 and JIS-K-7136 is 0.2% or more. .
(4) The light diffusion particle is an oxide of at least one element selected from the group consisting of Bi, Nd, Si, Al, Zr, and Ti, a composite oxide, and the oxide and the composite oxidation The light diffusion molded article according to any one of the above (1) to (3), comprising any one or more of at least any mixture of the above substances.
(5) The light diffusion molded article according to (4), wherein the light diffusion particles include at least a Bi oxide, a composite oxide, and a mixture of at least one of the oxide and the composite oxide.
(6) The light diffusion molded article according to any one of (1) to (5), wherein the light diffusion particles include at least one of a melamine resin, an acrylic resin, and a polystyrene resin.
(7) The light diffusion molded article according to any one of (1) to (6), wherein the light diffusion particles have a Z average particle diameter of 100 to 5000 nm.
(8) The light diffusion molded article according to any one of (1) to (7), wherein the number average particle diameter value of the light diffusion particles contained in the light diffusion molded article is 200 to 3000 nm.
(9) The above (1) to (8), wherein the particle size of the light diffusing particles of 15% or more based on the number of the light diffusing particles contained in the light diffusing molded product is in the range of 300 to 2000 nm. The light-diffusion molded object as described in any one of these.
(10) The light diffusion molded article according to any one of (1) to (9), wherein 0.001 to 3 parts by mass of the light diffusion particles are contained with respect to 100 parts by mass of the transparent resin binder.
(11) The light diffusion molded article according to any one of (1) to (10), wherein the polydispersity index of the light diffusion particles is 1.0 or less.
(12) The light diffusion molded article according to any one of (1) to (11), wherein the transparent resin binder contains a thermoplastic resin.
(13) The light diffusion molded article according to (12), wherein the thermoplastic resin contains a polycarbonate resin.
(14) A transparent screen film comprising the light diffusion molded article according to any one of (1) to (13) above.

According to the light diffusing molded article of the present invention and the transparent screen film containing the specific transparent resin binder and light diffusing particles, when displaying an image based on the image data, for example, blue and green, etc. Can maintain a good balance of various colors. Moreover, since the light-diffusion molded object of this invention and the film for transparent screens have high color reproducibility, the color tint intended to display can be reproduced faithfully in the image displayed.

3 is a graph showing average haze (%) values of 380 nm to 780 nm in the light diffusion molded articles of Examples and Comparative Examples. It is a figure which shows roughly the measuring method of the particle diameter based on the cross-sectional observation of a resin film.

Hereinafter, the present invention will be described in detail. In addition, this invention is not limited to the following embodiment, In the range which has the effect of invention, it can change arbitrarily and can implement.

[Light diffusion molding]
The light diffusion molded article of the present invention includes a transparent resin binder and light diffusion particles. Since the light diffusion molded article has high color reproducibility, it is particularly suitable for use as a light diffusion film such as a transparent screen film.

In the light diffusion molded body, 0.001 to 3 parts by mass of light diffusion particles (about 0.001 to about 3.0% by mass in the light diffusion molded body) is contained with respect to 100 parts by mass of the transparent resin binder. It is preferable. More preferably, the light diffusion molded article contains 0.01 to 1 part by weight of light diffusion particles with respect to 100 parts by weight of the transparent resin binder, and more preferably, light diffusion particles with respect to 100 parts by weight of the transparent resin binder. In an amount of 0.03 to 0.5 parts by mass, and particularly preferably 0.1 to 0.3 parts by mass of light diffusing particles with respect to 100 parts by mass of the transparent resin binder.
By adjusting the content of the light diffusing particles to the above-mentioned range, high transparency of the light diffusing molded body is ensured, image visibility such as color reproducibility is also improved, and sufficient scattering of transmitted light becomes possible. obtain.

<Transparent resin binder>
A transparent resin binder is used as a main constituent material of the light diffusion molded body. In order to improve the strength and durability of the transparent screen film, the transparent resin binder preferably contains a hard thermoplastic resin. Furthermore, in order to improve the transparency of the transparent screen film, it is preferable to include a highly transparent thermoplastic resin.
Specifically, the thermoplastic resin used as a component of the transparent resin binder is selected from the group consisting of polycarbonate resin, polyester resin, acrylic and methacrylic resin, polyolefin resin, cellulose resin, vinyl resin, and polystyrene resin. It is preferable to contain at least one kind.
In particular, the transparent resin binder preferably contains at least one selected from a polycarbonate resin and a polyester resin among the above-mentioned options of the thermoplastic resin.

For example, as the above polycarbonate resin, a — [O—R—OCO] — unit (R is an aliphatic group, an aromatic group, or both an aliphatic group and an aromatic group) containing a carbonate ester bond in the molecular main chain. And those having a linear structure or a branched structure) are not particularly limited. However, from the viewpoint of impact resistance and heat resistance, and stability as an aromatic dihydroxy compound, and also from the viewpoint of easy availability of those containing a small amount of impurities contained therein, aromatic polycarbonate is cited as a more preferable one. It is done. Examples of the aromatic polycarbonate include those having a bisphenol A skeleton.

Although there is no restriction | limiting in the specific kind of polycarbonate resin, For example, the polycarbonate polymer formed by making a dihydroxy compound and a carbonate precursor react is mentioned. At this time, in addition to the dihydroxy compound and the carbonate precursor, a polyhydroxy compound or the like may be reacted. Further, a method of reacting carbon dioxide with a cyclic ether using a carbonate precursor may be used. Further, the polycarbonate polymer may be a homopolymer composed of one type of repeating unit or a copolymer having two or more types of repeating units. At this time, the copolymer can be selected from various copolymerization forms such as a random copolymer and a block copolymer.

The method for producing the polycarbonate resin is not particularly limited, and any method can be adopted. Examples include an interfacial polymerization method, a melt transesterification method, a pyridine method, a ring-opening polymerization method of a cyclic carbonate compound, and a solid phase transesterification method of a prepolymer.

The molecular weight of the polycarbonate resin is preferably 10,000 to 35,000, more preferably 10,000 or more in terms of viscosity average molecular weight converted from the solution viscosity measured at a temperature of 25 ° C. using methylene chloride as a solvent. More preferably, it is 11,000 or more, more preferably 11,500 or more, and still more preferably 12,000 or more. Moreover, the viscosity average molecular weight of polycarbonate resin becomes like this. Preferably it is 32,000 or less, More preferably, it is 29,000 or less. By making the viscosity average molecular weight more than the lower limit of the above range, the mechanical strength of the resin molding of the present invention can be further improved, and by making the viscosity average molecular weight not more than the upper limit of the above range, It is possible to improve by suppressing the decrease in fluidity, and to improve the molding processability and easily perform the thin-wall molding process.
Two or more types of polycarbonate resins having different viscosity average molecular weights may be mixed and used, and in this case, a polycarbonate resin having a viscosity average molecular weight outside the above-mentioned preferred range may be mixed.
The viscosity average molecular weight [Mv] is obtained by using methylene chloride as a solvent and obtaining an intrinsic viscosity [η] (unit: dl / g) at a temperature of 25 ° C. using an Ubbelohde viscometer. , Η = 1.23 × 10 ⁻⁴ Mv ^0.83 . The intrinsic viscosity [η] is a value calculated from the following equation by measuring the specific viscosity [η _sp ] at each solution concentration [C] (g / dl).

Moreover, as the above-mentioned polyester resin, for example, PETG (polyethylene terephthalate modified with glycol by cyclohexanedimethanol) or the like is used.

Further, the transparent resin binder may contain a photocurable resin, a thermosetting resin, or the like as a component other than the thermoplastic resin. In this case, the transparent resin binder preferably contains 80% by mass or more of a thermoplastic resin, and more preferably contains 90% by mass or more of a thermoplastic resin.

The photocurable resin contained in the transparent resin binder may be any of an ultraviolet curable resin and an electron beam curable resin, such as an acrylic resin, a silicone resin, and an ester resin. Specific examples of UV curable resins include UV curable resins having an acryloyl group in the molecule, such as epoxy acrylate, urethane acrylate, polyester acrylate, polyol acrylate oligomers, polymers and monofunctional, bifunctional, Alternatively, a polyfunctional polymerizable (meth) acrylic monomer such as tetrahydrofurfuryl acrylate, 2-hydroxyethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, trimethylolpropane triacrylate, Mixtures of monomers, oligomers, polymers and the like such as pentaerythritol triacrylate and pentaerythritol tetraacrylate are used. In addition, you may mix | blend the photoinitiator etc. which are mix | blended normally with a photocurable resin.
Examples of the thermosetting resin contained in the transparent resin binder include phenol resin, polyimide resin, bismaleimide triazine resin, crosslinkable polyphenylene oxide, curable polyphenylene ether, melamine resin, urea resin, epoxy resin, and unsaturated polyester. Resin, alkyd resin, diallyl phthalate resin, xylene resin, (meth) acrylic resin, cresol novolac epoxy resin, phenol novolac epoxy resin, biphenyl epoxy resin, linear aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic ring Epoxy resins, halogenated epoxy resins, spirocyclic epoxy resins, bisphenol A, resorcinol and other novolac epoxy resins, bisphenol A epoxy resins, brominated bisphenol A Epoxy resin, etc. is used.

<Light diffusion particles>
The light diffusion molded body contains atomized light diffusion particles. As the light diffusion particles, for example, those containing a metal oxide are used. More specifically, the light diffusing particles include, for example, an oxide of at least one element selected from the group consisting of Bi, Nd, Si, Al, Zr, and Ti, a composite oxide, and the oxide And at least one of the composite oxides is preferably included. More preferably, the light diffusing particles contain at least one selected from bismuth oxide, zirconium oxide, silica, titania (titanium oxide), and alumina. As the light diffusion particles, particles containing bismuth oxide, that is, particles containing a bismuth oxide, a composite oxide, and a mixture of at least one of the oxide and the composite oxide are particularly preferable.

As the metal oxide light diffusing particles used in the present invention, those subjected to surface treatment may be used. As the surface treatment agent, inorganic materials and / or organic materials are preferable. Specific examples of the surface treating agent include metal oxides such as alumina, silica, and zirconia, silane coupling agents, titanium coupling agents, organic materials such as organic acids, polyols, and silicones.

In addition, the light diffusion molded body may contain a resin in addition to the above-described components. For example, particles containing a melamine resin, preferably composite spherical particles of melamine resin and silica, acrylic resin particles, polystyrene resin particles, and the like may be used. When composite spherical particles of melamine resin and silica are used as light diffusing particles, the haze value (%) of the light diffusing molded body is almost constant regardless of the wavelength (nm) of light, as will be described in detail later. Color reproducibility can be realized.

The light diffusing particles preferably have a Z average particle diameter of 100 nm to 5000 nm. The Z average particle diameter of the light diffusing particles is more preferably 150 nm to 4000 nm, and further preferably 200 nm to 3800 nm. Thus, a light diffusion molded article that employs light diffusion particles having a large diameter compared to light diffusion particles used in a conventional transparent screen for projection, for example, light diffusion particles having a particle diameter of about several tens of nanometers, As will be described in detail later, in particular, it is possible to realize a transparent screen having excellent color reproducibility.
The Z average particle diameter referred to in the present invention is data obtained by analyzing measurement data of a dynamic light scattering method such as a particle dispersion using a cumulant analysis method.

In the cumulant analysis, the average value of the particle diameter and the polydispersity index (PDi) are obtained. In the present invention, this average particle diameter is defined as the Z average particle diameter.
Specifically, it is as follows. First, the work of fitting a polynomial to the logarithm of the G1 correlation function obtained by measurement is called cumulant analysis, and the following formula LN (G1) = a + bt + ct ² + dt ³ + et ⁴ +...
Is called the second-order cumulant or Z-average diffusion coefficient.
A value obtained by converting the value of the constant b into a particle diameter using the viscosity of the dispersion medium and some apparatus constants is the Z average particle diameter. The value of the Z average particle diameter is the most important and stable value obtained by the dynamic light scattering method, and is a value suitable for quality control purposes as an index of dispersion stability. As for the coefficient c of the square term, the value 2c / b ² is called a polydispersity index (PDi).
The Z average particle size, which is an index of dispersibility in the present invention, can be specifically measured using the following method.
That is, a particle size measuring machine using dynamic light scattering, such as a Zetasizer Nano ZS measuring device manufactured by Malvern Co., Ltd., after the light diffusing particles are put into pure water and the particles are dispersed using ultrasonic waves. And the value of the Z average particle diameter can be determined.

The polydispersity index of the light diffusing particles is preferably 1.0 or less. Furthermore, the polydispersity index of the light diffusing particles is more preferably 0.8 or less, further preferably 0.7 or less, and particularly preferably 0.5 or less. Thus, by using light diffusing particles having a small polydispersity index value, light diffusing particles having extremely large diameters or extremely small diameters can be removed from the light diffusion molded article.

[Other components contained in light diffusion molded article]
The following additives may be included as components other than the transparent resin binder and the light diffusion particles in the light diffusion molded body. For example, in a light diffusion molded article used as a film for a transparent screen, it was selected from the group consisting of an ultraviolet absorber, a heat stabilizer, an antioxidant, a flame retardant, a flame retardant aid, a release agent, and a colorant. At least one additive. An antistatic agent, a fluorescent whitening agent, an antifogging agent, a fluidity improving agent, a plasticizer, a dispersing agent, an antibacterial agent and the like may be added as long as the desired physical properties are not significantly impaired.

The following can be used as an ultraviolet absorber added to a light-diffusion molded object. Examples of organic ultraviolet absorbers include triazine ultraviolet absorbers, benzotriazole ultraviolet absorbers, and benzophenone ultraviolet absorbers.
Specific examples of triazine ultraviolet absorbers include 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyloxy) -phenol, 2- (2-hydroxy-4) -[1-octyloxycarbonylethoxy] phenyl) -4,6-bis (4-phenylphenyl) -1,3,5-triazine, 2- [4-[(2-hydroxy-3-tridecyloxypropyl) Oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2,4-bis [2-hydroxy-4-butoxyphenyl] -6- ( 2,4-dibutoxyphenyl) -1,3,5-triazine, 2- [4-[(2-hydroxy-3-dodecyloxypropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2 4-dimethylphenyl) -1,3,5-triazine and 2- [4-[(2-hydroxy-3- (2′-ethyl) hexyl) oxy] -2-hydroxyphenyl] -4,6- Examples thereof include bis (2,4-dimethylphenyl) -1,3,5-triazine.

Specific examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2-ethylhexyl-3- [3-tert -Butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate, 2- [5-chloro (2H) -benzotriazol-2-yl] -4-methyl-6 -(Tert-butyl) phenol, 2- (2H-benzotriazol-2-yl) -4,6-di-tert-pentylphenol, 2- (2H-benzotriazol-2-yl) -6-dodecyl-4 -Methylphenol, 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazole 2-yl) phenol), 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', and 5'-di-tert-butylphenyl) -5-chlorobenzo And triazole, 2- (2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6 ″ -tetrahydrophthalimidomethyl) -5′-methylphenyl) benzotriazole.

Specific examples of the benzophenone ultraviolet absorber include sodium hydroxymethoxybenzophenone sulfonate, 2-hydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxy Examples thereof include benzophenone and hydroxymethoxybenzophenone sulfonic acid.

Moreover, you may add metal type ultraviolet shielding agents, such as a titanium oxide and a zinc oxide, to a light-diffusion molded object.
The content of the ultraviolet absorber and the ultraviolet shielding agent in the light diffusion molded body is preferably 0.01 to 5.0% by mass, more preferably 0.05 to 3%, based on the total mass of the light diffusion molded body. It is 0.0% by mass, more preferably 0.1 to 1.0% by mass.

The light diffusion molded article of the present invention preferably contains an antioxidant.
Antioxidants include phenolic antioxidants, amine antioxidants, phosphorus antioxidants, thioether antioxidants, phosphorus antioxidants and phenolic antioxidants (more preferably hinders). Dophenol antioxidants) are preferred. Among these, phosphorus-based antioxidants are particularly preferable because they can form a resin molded article excellent in hue. Among the phosphorus antioxidants, phosphite stabilizers are preferable, and the phosphite stabilizer is preferably a phosphite compound represented by the following formula (1) or (2).

(In Formula (1), R ¹ and R ² each independently represents an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms.)

(In Formula (2), R ³ to R ⁷ each independently represents a hydrogen atom, an aryl group having 6 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms.)

In the above formula (1), the alkyl groups represented by R ¹ and R ² are preferably each independently a linear or branched alkyl group having 1 to 10 carbon atoms. When at least one of R ¹ and R ² is an aryl group, an aryl group represented by any of the following general formulas (1-a), (1-b), or (1-c) is preferable.

(In the formula (1-a), R ^A each independently represents an alkyl group having 1 to 10 carbon atoms. In the formula (1-b), R ^B each independently represents an alkyl group having 1 to 10 carbon atoms. Represents an alkyl group.)

The content of the antioxidant in the light diffusion molded body is preferably 0.005 to 1.0 mass%, more preferably 0.01 to 0.5 mass%, based on the total mass of the light diffusion molded body. More preferably, it is 0.02 to 0.3% by mass.

In the light diffusion molded article, the transparent resin binder and the light diffusing particles are preferably contained in total of 60% by mass or more, more preferably 80% by mass or more, based on the total mass of the light diffusion molded product. Particularly preferably 90% by mass or more is contained.

[Manufacture of light diffusion moldings]
The light diffusion molded body is manufactured by blending the above-described transparent resin binder and material substances such as light diffusion particles. For example, each component such as a transparent resin binder is mixed using a tumbler and further melt-kneaded by an extruder to produce a pellet-shaped resin composition as a material for the transparent resin binder. Here, the form of the resin composition is not limited to a pellet form, and may be a flake form, a powder form, a bulk form, or the like.
Furthermore, a light diffusion molded body is obtained by molding the resin composition into a predetermined shape. For example, the light-diffusion molded object as a film for transparent screens can be manufactured by the process of processing a resin composition into a film or a sheet form.

[Transparent screen film]
The film for transparent screens of this invention contains the above-mentioned light diffusion molded object. More specifically, the transparent screen film of the present invention is formed mainly by a light diffusion molded body, and preferably only by a light diffusion molded body.
Thus, for example, the thickness of the light diffusion molded article utilized as a transparent screen film is preferably 10 μm to 3000 μm (0.01 mm to 3 mm), more preferably 30 μm to 2000 μm, and particularly preferably. Is 50 μm to 1000 μm.

As is clear from the fact that the transparent screen film contains the above-mentioned light diffusion molded article, the transparent screen film also contains a transparent resin binder and light diffusion particles.
The light diffusing particles contained in the transparent screen film preferably have a Z average particle diameter of 100 nm to 5000 nm, and the Z average particle diameter is more preferably 150 nm to 4000 nm, still more preferably 200 nm to 3800 nm. .
The Z average particle diameter of the light diffusing particles containing a bismuth-based metal oxide, which will be described in detail later, is, for example, 500 nm to 3000 nm, and more preferably 600 nm to 2600 nm. The Z average particle diameter of the light diffusing particles which are melamine resin and silica composite particles is, for example, 500 nm to 5000 nm, preferably 1000 nm to 4000 nm.
In order to confirm the value of the Z average particle diameter of the light diffusing particles, the solvent for dissolving the transparent screen film is not particularly limited as long as the transparent screen film can be dissolved. Solvents with high solubility are preferred, and specific examples include dichloromethane, toluene, xylene, tetrahydrofuran, 1,4-dioxane, dimethylformamide, N-methylpyrrolidone, ethyl acetate, cyclohexanone, acetone, methyl ethyl ketone, methanol, cyclohexane and the like. Among these, dichloromethane (CH ₂ Cl ₂ ) is preferable.

In order to grasp the actual distribution of the light diffusion particles in the transparent screen film, which is a light diffusion molded product, more accurately, the light diffusion in the state of being dispersed in the transparent screen film is observed by observing the cross section of the transparent screen film. It is preferable to measure the particle diameter of the particles and calculate the average particle diameter, for example.
That is, the particle diameter of the light diffusing particles contained in the transparent screen film is measured from the film image by a method described in detail later, and the value of the number average particle diameter is calculated from the obtained particle diameter data.

The number average value of the particle diameters of the light diffusing particles contained in the light diffusion molded article thus calculated is preferably 200 to 3000 nm, more preferably 240 to 2700 nm, and preferably 530 to 2400 nm. Further preferred.
In addition, regarding the particle size distribution of the light diffusing particles in the transparent screen film, the light diffusing particles having a particle size in the range of 300 to 2000 nm account for 15% or more based on the total number of the light diffusing particles. It is preferable to occupy, more preferably 20% or more, still more preferably 40% or more, particularly preferably 60% or more.

In addition, about the component of the light-diffusion particle | grains in the film for transparent screens, it is as having described in the column of the said <light-diffusion particle>, for example, from the group which consists of Bi, Nd, Si, Al, Zr, and Ti. It is preferable that any one or more of at least one selected element oxide, composite oxide, and a mixture of at least one of the oxide and the composite oxide is included. The light diffusing particles in the transparent screen film are more preferably at least one selected from bismuth oxide, zirconium oxide, silica, titania (titanium oxide) and alumina, and particularly preferably an oxide of bismuth and a composite oxide. And a mixture of at least one of the oxide and the composite oxide.
Further, the light diffusing particles in the transparent screen film may contain a resin in addition to the above components or separately from the above components. For example, the light diffusing particles may contain particles containing melamine resin, preferably composite spherical particles of melamine resin and silica, particles of acrylic resin, particles of polystyrene resin, and the like.
Screen light having these light diffusing particles, in particular, the above-mentioned light diffusing particles listed as preferred options, for example, light diffusing particles containing bismuth oxide, etc., particularly improves the color reproducibility of images during projector projection. be able to.

When the above-mentioned light diffusion particles are used, it is possible to maintain good color reproducibility while maintaining a wide viewing angle of the transparent screen. That is, in the conventional transparent screen, generally, the particle diameter of the light diffusing particles has been reduced to improve the diffusivity and widen the viewing angle. There has been a problem of color reproducibility such as an excess of. On the other hand, when the above-mentioned types of light diffusing particles are used, it is possible to realize good color reproducibility while widening the viewing angle.
In addition, the component of the light-diffusion particle | grains in the film for transparent screens can be confirmed by an energy dispersive X-ray (EDX) analysis, for example.

Further, the content of the light diffusing particles in the transparent screen film is the same as the content in the above-mentioned light diffusing molded article. That is, the transparent screen film preferably contains 0.001 to 3 parts by mass (about 0.001 to about 3.0% by mass) of light diffusing particles with respect to 100 parts by mass of the transparent resin binder. Preferably, the transparent screen film contains 0.01 to 1 part by weight of light diffusing particles with respect to 100 parts by weight of the transparent resin binder, and more preferably, the light diffusing particles with respect to 100 parts by weight of the transparent resin binder. 0.03 to 0.5 parts by mass, and particularly preferably 0.1 to 0.3 parts by mass of light diffusing particles with respect to 100 parts by mass of the transparent resin binder.

For example, in a light diffusion molded article that is a film for a transparent screen, the value of the total light transmittance is preferably 70% or more, more preferably 75% or more, and particularly preferably 80% or more. As described above, the transparent screen film having a high total light transmittance value can clearly display the image projected from the projector. The value of the total light transmittance in this specification is a value based on JIS-K-7361 and JIS-K-7136 described later.

For example, in a light diffusion molded article that is a transparent screen film, the haze value is preferably 0.2% or more, more preferably 0.8% or more, and further preferably 3% or more. is there. As described above, in a transparent screen film having a high haze value to a certain degree or more, the transmitted light can be sufficiently scattered, and the visibility of the projected image is improved.
The haze value of the light diffusion molded article is preferably 80% or less, the haze value is more preferably 75% or less, still more preferably 72% or less, particularly preferably 45% or less, for example, 20% or less. is there. Thus, the transparent screen film having a sufficiently low haze value has high transparency and excellent aesthetics.
As described above, when a light diffusion molded article having a haze value in a preferable range is used, both the effect of improving the visibility by projecting an image favorably and high transparency can be achieved in the transparent screen film.
The haze value in the present specification is a value based on JIS-K-7361 and JIS-K-7136 described later.

In the light diffusion molded article, an average haze (A) of 380 nm to 480 nm and an average haze (B) of 380 nm to 780 nm measured by a method according to JIS-K-7361 and JIS-K-7136. The value of ratio (A) / (B) is 0.8 or more and 1.6 or less. The value of average haze (A) is an average value of haze values measured between 380 nm and 480 nm, for example, every 5 nm in accordance with JIS-K-7361 and JIS-K-7136. Similarly, the average haze (B) is an average value of haze values measured between 380 nm and 780 nm, for example, every 5 nm in accordance with JIS-K-7361 and JIS-K-7136.

The value of (A) / (B), which is the ratio of the above average haze (A) value and average haze (B) value, is preferably 0.9 or more and 1.5 or less, more preferably 0. .95 or more and 1.45 or less, and more preferably 1.0 or more and 1.4 or less.

In FIG. 1, the above-described average haze (A) value of 380 nm to 480 nm and the average haze value (B) of 380 nm to 780 nm are represented by symbols (A) and (B), respectively. The average haze value in the wavelength region.
Then, the light diffusion molded article whose ratio (A) / (B) is in the above-mentioned range and close to 1.0 has a haze value in the blue region (380 nm to 480 nm) of the diffused light of the entire diffused light. Although it is close to the average haze value in the wavelength region (380 nm to 780 nm), the color balance of diffused light is good. For example, the light diffusion molded article of Example 1 shown by a substantially flat curve in FIG. 1 has a good color balance of diffused light because the value of the ratio (A) / (B) is 1.0. is there. On the other hand, the light diffusion molded article of Comparative Example 5 shown by the downward-sloping curve in FIG. 1 has a ratio (A) / (B) value of 2.1, which is diffused compared to Example 1. The color balance of light is inferior.

Further, in the light diffusion molded body, H (Z) / H (Y) which is a ratio of H (Z) and H (Y) calculated by the following formulas (I) and (II), respectively. Is preferably in the range of 0.8 to 1.5.
H (Y) = τd (Y) / τt (Y) (I)
H (Z) = τd (Z) / τt (Z) (II)
Here, in these equations, the values of τt (Y) and τt (Z) are measured in the measurement wavelength range of 380 nm to 780 nm by a method according to JIS-K-7361 and JIS-K-7136. This is a tristimulus value in the XYZ display system calculated by a method based on JIS-Z-8722 based on the measured value of total light transmittance (τt).
The values of τd (Y) and τd (Z) in these equations are measured in the measurement wavelength range of 380 nm to 780 nm by a method based on JIS-K-7361 and JIS-K-7136. This is a tristimulus value in the XYZ display system calculated by a method based on JIS-Z-8722 based on the value of diffused light transmittance (τd).

The value of H (Z) / H (Y) described above is more preferably 0.90 to 1.45, still more preferably 0.95 to 1.40, and particularly preferably 1.00 to 1. 35.
A light diffusion molded product having a value of H (Z) / H (Y) within the above range has a good balance between haze H (Z) of blue light and haze H (Y) of green light, and is visually recognized. It has the characteristic that the color of diffused light is close to nature. Thus, it is important to adjust the value of H (Z) / H (Y). The reason is as follows. That is, in order to increase the viewing angle of a transparent screen using a light diffusion molded body, for example, when light diffusion particles having a particle size of about 200 nm are added, the haze in the short wavelength region increases, so the value of H (Z) is Easy to grow. For this reason, in order to achieve both a wide viewing angle and a good color, it is important to adjust the value of H (Z) / H (Y) in addition to controlling the particle size of the light diffusing particles and selecting the particle type. is there.

The ratio (A) / (B) of the average haze (A) of 380 nm to 480 nm and the average haze (B) of 380 nm to 780 nm, and the ratio of H (Z) and H (Y) It is also possible to evaluate whether or not the light diffusion degree of the light diffusion molded article is good depending on whether the value of H (Z) / H (Y) is within the predetermined range described above, for example. It is. That is, the value of the ratio (A) / (B) and the value of H (Z) / H (Y) can also be used as an index in the method for evaluating the light diffusion degree of the light diffusion molded body.

For example, in a light diffusion molded body that is a film for a transparent screen, the diffusivities when the wavelengths of irradiation light to be irradiated are 400 nm, 500 nm, 600 nm, and 700 nm are B (400), B (500), and B ( 600) and B (700), the relative standard deviation of B (400), B (500), B (600), and B (700) (hereinafter also simply referred to as relative standard deviation) is 0 to 20 % Is preferable. More preferably, the value of the relative standard deviation of B (400), B (500), B (600), and B (700) is 18% or less, and particularly preferably 15% or less.

In this way, when light of different wavelengths is incident (irradiated), a transparent screen film having a sufficiently small difference in diffusivity value according to the wavelength range provides a good balance of various colors in the projected image. Color reproducibility is improved.

Moreover, it is preferable that the YI value ((DELTA) YI value based on JISZ8722) of the film for transparent screens is 5 or less. More preferably, the YI value (ΔYI value) of the transparent screen film is 4.2 or less, and particularly preferably 3.0 or less.
As described above, in the transparent screen film having a small YI value (ΔYI value), the color change that can be caused by the decomposition of the resin of the material, in particular, the color change to yellow is suppressed. For this reason, in a transparent screen film having a small YI value (ΔYI value), the color reproducibility can be further improved.

The transparent screen film of the present invention is suitably used for the production of a transparent screen. In addition, “transparent” described in the specification of the present application means that the image has a transparency that can be projected on a screen and can achieve a certain degree of transmission visibility. The transparent screen produced by the transparent screen film of the present invention has not only the characteristics of excellent color reproducibility and a wide viewing angle but also the characteristics of transparency and high visible light transmittance.

In the transparent screen, layers other than the transparent screen film of the present invention may be laminated. For example, a support layer for supporting the transparent screen film, a protective layer for protecting the surface of the transparent screen film, and an adhesive layer for adhering other layers to the transparent screen film may be laminated. good.
The adhesive layer of the transparent screen is, for example, a layer for attaching a film to the transparent screen, and the adhesive layer is preferably formed using an adhesive composition. Examples of the pressure-sensitive adhesive composition include natural rubber-based, synthetic rubber-based, acrylic resin-based, polyvinyl ether resin-based, urethane resin-based, and silicone resin-based so as not to impair the optical characteristics and transparency of the transparent screen film. Etc. are preferably used. Specific examples of the synthetic rubber-based pressure-sensitive adhesive composition include styrene-butadiene rubber, acrylonitrile-butadiene rubber, polyisobutylene rubber, isobutylene-isoprene rubber, styrene-isoprene block copolymer, styrene-butadiene block copolymer, styrene. -Ethylene-butylene block copolymer. Specific examples of the silicone resin-based pressure-sensitive adhesive composition include dimethylpolysiloxane. These components can be used alone or in combination of two or more. Among these, it is preferable to form an adhesive layer using an acrylic adhesive.

The thickness of the transparent screen is, for example, 0.45 mm to 2 mm, more preferably 0.48 mm to 1.5 mm, and particularly preferably 0.5 mm (500 μm) to 1.0 mm.

In addition, about the shape of the film for transparent screens of this invention, any of a plane and a curved surface may be sufficient, and what was processed two-dimensionally or three-dimensionally may be sufficient. The processing method is not particularly limited, but preferred examples include a thermal processing method, a punching method, a cold bending method, a drawing method, and the like, and a hot bending method, a curved surface processing method, a free processing method, and the like. A blow molding method and the like are more preferable, and a press molding method, a vacuum molding method, a compressed air molding method, a natural standing method, and the like are particularly preferable.

[Projection of image]
In the projection of an image, a transparent screen manufactured by the transparent screen film of the present invention can be used. In video projection, the image may be projected from the back of the transparent screen or from the front. That is, the transparent screen may be a transmissive screen for observing transmitted light or a reflective screen for observing reflected light.

[Method for producing film for transparent screen]
The transparent screen film of the present invention is produced using a light diffusion molded article as described above. For example, a predetermined amount of light diffusing particles is added to the light diffusing molded body and melt kneaded. And the pellet of the light-diffusion molded object containing a light-diffusion particle is obtained by strand cutting, for example. The transparent screen film can be produced by extruding the thus obtained light diffusion molded article pellets with, for example, a film extruder.

Furthermore, the shape of the transparent screen film is adjusted by appropriately selecting and employing the various processing methods described above. Thus, the transparent screen film whose shape is appropriately adjusted is used for the production of a transparent screen. More specific production methods include the methods of the following examples.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not construed as being limited to the following examples.

The raw materials used in Examples and Comparative Examples are as follows.
[material]
・ Thermoplastic resin (A) (transparent resin binder)
(A1) Aromatic polycarbonate resin obtained by interfacial polymerization using bisphenol A as a starting material (Iupilon S-3000F manufactured by Mitsubishi Engineering Plastics Co., Ltd., viscosity average molecular weight: 22,000)
(A2) Modified polyethylene terephthalate resin (SKYGREEN S2008, SK Chemicals, viscosity average molecular weight: 31,000)
(A3) UV curable resin

・ Light diffusion particles (B)
(B1) Bismuth metal oxide (bismuth oxide containing neodymium oxide, 42-920A manufactured by Toago Material Technology Co., Ltd.)
(B2) Particles obtained by crushing and classifying bismuth-based metal oxide (bismuth oxide containing neodymium oxide, 42-920A manufactured by Toago Material Technology Co., Ltd.) Machine (model: Super Jet Mill SJ-500) and Nissin Engineering Co., Ltd. air classifier (model: Aerofine Crushia AC-20). Processed particles were obtained by removing coarse particles with a classifier. The obtained particles were dispersed in pure water, and the particle size distribution was measured using a particle size distribution measuring apparatus using a laser diffraction scattering method (MT3300EXII manufactured by Microtrack Bell Co., Ltd.). As a result, D50 of B1 particles before processing was 0.94 μm, and B2 particles after processing was 0.27 μm.
(B3) Silica particles (silicon dioxide, Admanano YA050C-SP3 manufactured by Admatechs Co., Ltd.)
(B4) Silica particles (silicon dioxide, Admafine SO-C1 manufactured by Admatechs Co., Ltd.)
(B5) Silica particles (Silicon dioxide, Admafine SC-2500SQ manufactured by Admatechs Co., Ltd.)
(B6) Silica particles (silicon dioxide, Admafine SC-C6 manufactured by Admatechs Co., Ltd.)
(B7) Alumina particles (aluminum oxide, Admafine AO-502 manufactured by Admatechs Co., Ltd.)
(B8) Zirconia particles (zirconium oxide, UEP manufactured by Daiichi Rare Element Chemical Industries, Ltd.)
(B9) Zirconia particles (zirconium oxide, SPZ manufactured by Daiichi Rare Element Chemical Industries, Ltd.)
(B10) Titania particles (titanium oxide, TITANIX JR-405 manufactured by Teika Co., Ltd.)
(B11) Titania particles (titanium oxide, TITANIX JR-301 manufactured by Teika Co., Ltd.)
(B12) Melamine resin and silica composite particles (Nissan Chemical Co., Ltd. Opt Beads 2000M)

・ Antioxidant (C)
Bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite (phosphorus-based antioxidant, stopper ADEKA STAB PEP-36)
・ Other additives (D1) Release agent Glycerin monostearate (Rikenmar S-100A manufactured by Riken Vitamin Co., Ltd.)
(D2) UV absorber Triazine UV absorber (Tinvin 1577 ED manufactured by BASF Japan Ltd.)

[Measurement of Z average particle diameter and polydispersity index (Pdi) of light diffusing particles]
The Z average particle diameter and polydispersity index (Pdi) of the light diffusing particles (B) are determined by cumulant analysis from the measurement results using the Malvern Zetasizer Nano ZS measuring device using the dynamic light scattering method. It was. The measurement was performed at room temperature, and a dispersion liquid in which the light diffusing particles (B) were dispersed in pure water at a concentration of 0.1% by weight was measured. Note that ultrasonic waves were used for dispersion of the light diffusing particles (B).
The polydispersity index (PDi) is an index that defines the particle size distribution of particles. The narrower the particle size distribution is, the closer PDi approaches to zero. Conversely, the particle size distribution is wide, that is, the polydispersity is large. As PDi increases.

[Production of thermoplastic resin pellets with added light diffusion particles]
With respect to the above-mentioned thermoplastic resins (A1) and (A2), the light diffusing particles (B), the antioxidant (C), and other additives (D) are added in the amounts shown in Table 1, respectively. Added. Then, after mixing resin etc. for 20 minutes with a tumbler, melt-kneaded at a cylinder temperature of 280 ° C. by a twin screw extruder with a screw diameter of 26 mm (“TEM26SS” manufactured by Toshiba Machine Co., Ltd.), and by strand cutting Pellets were obtained.

[Production of thermoplastic resin film to which light diffusing particles are added (1)]
The obtained pellets were melted and extruded with a vented twin-screw film extruder (TEX-30α manufactured by Nippon Steel Co., Ltd.) with a T-die lip having a screw diameter of 30 mm to produce a film-like molded product. .

[Production of thermoplastic resin film with added light diffusion particles (2)]
Of Example and Comparative Example shown in Table 1, only Example 12 was formed as follows by a method different from the above-described production (1) of the thermoplastic resin film.
90/10 (mass ratio) of hexafunctional urethane acrylate (Negami Kogyo Co., Ltd. UN-3320HC) and bifunctional acrylate (Shin Nakamura Chemical Co., Ltd. A-BPE-4 (ethoxylated (4 mol) bisphenol A diacrylate)) The photopolymerization initiator (TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide) manufactured by BASF) was added in an amount of 5% by mass with respect to the resin component described above. A3) 1.0% by mass of component (B12) (Opto Beads 2000M manufactured by Nissan Chemical Industries, Ltd.) is added to the UV curable resin component, and propylene glycol monomethyl ether is added to obtain a solid content of 50% by mass. The obtained liquid composition was applied to a 75 μm thick PC film with a bar coater (# 8) and dried. After (100 ° C. x2 min), it was UV cured (integrated light quantity 250 mJ / cm ^2).

The particle size of the light diffusing particles contained in the resin film thus molded was measured by a method of observing the cross-sectional shape of the film (cross-sectional observation method).

[Measurement of particle size of light diffusion particles in resin film by cross-sectional observation (cross-sectional observation method)]
The resin film molded by the above-described method was subjected to cross-section processing by ion milling for about 3 hours, and the obtained cross-section was observed by a field emission scanning electron microscope (FE-SEM). The apparatus used for this ion milling cross-section processing was IM-4000 manufactured by Hitachi High-Technologies, and the apparatus used for cross-sectional observation by FE-SEM was SU-8220 manufactured by Hitachi High-Technologies. As an image observation mode for cross-sectional observation, an LA-BSE image was used, and the particle diameter of particles that could be observed when the magnification was 2000 times was measured. For each film, at least 10 or more particles were observed.

Based on the above observation data, the particle diameter d of each particle is
The calculation was made based on the formula (particle size in the long side direction (a) + particle size in the short side direction (b)) / 2 = d. The outline of the particle diameter (a) in the long side direction and the particle diameter (b) in the short side direction is as shown in FIG. 2, and the particle diameter (a) is the largest of the diameters passing through the center point of the cross section of the particle. The particle diameter (b) is the shortest particle diameter among the diameters passing through the center point of the cross section of the particle.
Further, the value of the average particle diameter of a large number of particles was used as the number average particle diameter Dav, and calculation was performed according to the following formula Σ (nd) / Σ (n) = Dav. In this formula, d represents the particle diameter of each particle, that is, each particle diameter, and n represents a number-based percentage. Further, the ratio of the number of particles having a particle diameter d in the range of 300 to 2000 nm to the total number of observable particles was determined.
Furthermore, it was confirmed by energy dispersive X-ray (EDX) analysis that the observed particles were light diffusing particles that are targets for particle diameter calculation. The apparatus used for EDX is X-Max ^{N for} Horiba.

[Evaluation of optical properties of film]
The optical characteristics of the molded articles produced in the above examples and comparative examples were evaluated as follows.
First, the total light transmittance (%) and haze (%) of the molded product were measured using a haze meter (trade name: HM-150, manufactured by Murakami Color Research Laboratory Co., Ltd.) and JIS-K-7361 and The measurement was performed according to JIS-K-7136.
Next, the image clarity of the molded product was measured for the image clarity of the transmitted light of the molded product in accordance with JIS K7374 using an image clarity measuring machine (Model: ICM-1T manufactured by Suga Test Instruments Co., Ltd.) The image clarity (%) when measured with an optical comb width of 0.125 mm was defined as image clarity.

Further, the total light transmittance (%), diffused ray transmittance (%), and haze (%) for each wavelength of the molded product are measured with a spectral haze meter (manufactured by Murakami Color Research Laboratory, Model: HSP-150VIR type). ) In accordance with JIS-K-7361 and JIS-K-7136.
The measurement was performed every 5 nm in the measurement wavelength range from 380 nm to 780 nm.
The tristimulus values in the XYZ display system are calculated from the obtained total light transmittance [τt] and diffused light transmittance at each wavelength from the values of [τd] according to JIS-Z-8722, and the total light transmittance is calculated. Tristimulus values of rate [τt (X), τt (Y), τt (Z)] and tristimulus values of diffuse light transmittance [τd (X), τd (Y), τd (Z)] were obtained. Based on the tristimulus values of [τd] and the total light transmittance [τt] and the diffused light transmittance obtained, a tristimulus value of haze was calculated according to the following formula.
H (X) = τd (X) / τt (X)
H (Y) = τd (Y) / τt (Y)
H (Z) = τd (Z) / τt (Z)

And H (X) / H (Y) and H (Z) / H (Y) were calculated from the tristimulus values of haze. H (X) indicates the haze of red light, H (Y) indicates the haze of green light, H (Z) indicates the haze of blue light, and the H (X) / H (Y) value corresponds to the haze of green light. The ratio of haze of red light is represented, and the H (Z) / H (Y) value represents the ratio of haze of blue light to haze of green light. That is, when the value of H (X) / H (Y) is large, the diffusion of red light is strong, and when the value of H (Z) / H (Y) is large, the diffusion of blue light is strong. . When the light diffusivity changes for each wavelength, uneven color of the diffused light occurs. Therefore, the light diffusion molded body is required to have no light diffusivity different for each wavelength, and H (Z) / H (Y ) And H (X) / H (Y) are required to be close to 1.

Further, in the obtained haze [H] at each wavelength, the average haze (A) of 380 to 480 nm and the average haze (B) of 380 to 780 nm were defined, and the ratio (A) / (B) was obtained. Since the average haze (A) of 380 to 480 nm indicates the haze of blue light, (A) / (B) represents the ratio of the haze of blue light to the average haze. That is, when the value of H (X) / H (Y) is large, the diffusion of red light is strong, and when the value of (A) / (B) is large, the diffusion of blue light is strong. When the light diffusivity changes for each wavelength, uneven color of the diffused light occurs. Therefore, the light diffusion molded article is required to have no light diffusivity different for each wavelength, and (A) / (B) The value is required to be close to 1.

Next, the transparency of the molded product, the visibility of the projector image when used as a transparent screen, and the color of the projector were visually evaluated based on the following criteria.

[Transparency evaluation criteria]
Especially good: the film was very transparent.
Good: The film was transparent.
Slightly poor: The film was slightly cloudy and inferior in transparency.
Defect: The film was cloudy and poor in transparency.

[Production and evaluation of transparent screens]
As a transparent screen, the films produced in the above-mentioned examples and comparative examples were placed at a position 12 cm away from the image projection lens of an ultrashort focus projector (trade name: PJ WX4152 manufactured by Ricoh Co., Ltd.). Next, an image was projected onto the screen from below 60 °, and the focus knob of the projector was adjusted so that the position of the screen was in focus. Regarding the luminance uniformity of the projector image, the image visibility when observed from the front rear, the image visibility when observed from 1 m behind 45 ° obliquely, and the color of the image are visually evaluated based on the following criteria. did. The image visibility was evaluated in a dark room by observing the same surface of the projector, that is, screen reflected light. The evaluation results are shown in Table 2 below.

[Evaluation criteria for uniformity of image brightness]
Particularly good: The brightness was very uniform no matter what direction the screen image was viewed.
Good: The brightness was uniform no matter what direction the screen image was viewed.
Slightly bad: The brightness may vary depending on the viewing angle of the screen image.
Defect: The brightness was different and non-uniform depending on the viewing angle of the screen image.
[Evaluation criteria for image color]
Particularly good: The color reproducibility of the screen image was very high.
Good: The color reproducibility of the screen image was high.
Defect: The screen image is very blue and the color reproducibility is low.
Especially bad: The blueness of the screen image was particularly strong and the color reproducibility was very low.

Claims

A light diffusion molded article containing a transparent resin binder and light diffusion particles,
Ratio (A) / (B) of average haze (A) of 380 nm to 480 nm and average haze (B) of 380 nm to 780 nm measured by a method according to JIS-K-7361 and JIS-K-7136 ) Is a light diffusion molded article having a value of 0.8 to 1.6.
The value of H (Z) / H (Y), which is the ratio of H (Z) and H (Y) calculated by the following formulas (I) and (II), is 0.8-1 The light diffusion molded article according to claim 1, which is in a range of .5.
H (Y) = τd (Y) / τt (Y) (I)
H (Z) = τd (Z) / τt (Z) (II)
However, the values of τt (Y) and τt (Z) in the above formula are measured in a measurement wavelength range of 380 nm to 780 nm by a method in accordance with JIS-K-7361 and JIS-K-7136. Tristimulus values in the XYZ display system calculated by a method based on JIS-Z-8722 based on the value of total light transmittance (τt),
The values of τd (Y) and τd (Z) in the above formula are diffused light measured in a measurement wavelength range of 380 nm to 780 nm by a method based on JIS-K-7361 and JIS-K-7136. Tristimulus values in the XYZ display system calculated by a method based on JIS-Z-8722 based on the value of transmittance (τd).
The light diffusion molded article according to claim 1 or 2, wherein the haze value measured by a method according to JIS-K-7361 and JIS-K-7136 is 0.2% or more.
The light diffusion particle is an oxide of at least one element selected from the group consisting of Bi, Nd, Si, Al, Zr, and Ti, a composite oxide, and at least the oxide and the composite oxide The light diffusion molded article according to any one of claims 1 to 3, comprising any one or more of any mixture.
The light diffusion molded article according to claim 4, wherein the light diffusion particles include at least a Bi oxide, a composite oxide, and a mixture of at least one of the oxide and the composite oxide.
The light diffusion molded article according to any one of claims 1 to 5, wherein the light diffusion particles include at least one of a melamine resin, an acrylic resin, and a polystyrene resin.
The light diffusion molded article according to any one of claims 1 to 6, wherein the Z average particle diameter of the light diffusion particles is 100 to 5000 nm.
The light diffusion molded article according to any one of claims 1 to 7, wherein the value of the number average particle diameter of the light diffusion particles contained in the light diffusion molded article is 200 to 3000 nm.
The particle diameter of the light diffusing particles of 15% or more based on the number of the light diffusing particles contained in the light diffusing molded product is in a range of 300 to 2000 nm. The light-diffusion molded object of description.
10. The light diffusion molded article according to claim 1, wherein 0.001 to 3 parts by mass of the light diffusion particles are contained with respect to 100 parts by mass of the transparent resin binder.
The light diffusion molded article according to any one of claims 1 to 10, wherein a polydispersity index of the light diffusion particles is 1.0 or less.
The light diffusion molded body according to any one of claims 1 to 11, wherein the transparent resin binder contains a thermoplastic resin.
The light diffusion molded article according to claim 12, wherein the thermoplastic resin includes a polycarbonate resin.
A transparent screen film comprising the light diffusion molded article according to any one of claims 1 to 13.