CN103665690B - Light diffusion body - Google Patents

Abstract

There is provided a kind of and guarantee sufficient light transmission, light diffusing and photostabilization and can the light diffusion body of slimming.By be dispersed with in substrate resin resin particle, mineral compound light-diffusing resin composition be shaped and make light diffusion body.Described resin particle be by the polymer formation of the monomer mixture comprising (methyl) acrylic acid or the like monofunctional monomer and polyfunctional monomer, the polymer particle of volume average particle size 2 ~ 10 μm, specific refractory power 1.540 ~ 1.560.Described mineral compound to be volume average particle size the be barium sulfate of 0.4 ~ 0.7 μm.Described light-diffusing resin composition, relative to this light-diffusing resin composition of 100 weight parts, comprises resin particle described in 1.5 ~ 2.5 weight parts.In addition, resin particle described in described light-diffusing resin composition and described mineral compound containing than with mass ratio range, in the scope of 1:0.5 ~ 1:1.35.

Description

light diffuser

technical field

The present invention relates to a light diffuser having translucency and light diffusibility.

Background technique

Conventionally, light diffusers formed of resin compositions containing base resins such as acrylic resins, polycarbonate resins, and styrene resins have been used in lighting fixtures as light diffusers for diffusing light from a light source. (for example, a lighting cover that covers the light source).

Conventionally, fluorescent lamps and incandescent lamps have been widely used as light sources for lighting fixtures, but in recent years, LEDs have been gradually used instead of fluorescent lamps and incandescent lamps for the purpose of prolonging their lifespan. Fluorescent lamps and incandescent lamps emit light in all directions, while LEDs emit light forward, and have higher directivity than fluorescent lamps and incandescent lamps. In addition, in a lighting fixture using an LED as a light source, for example, a lighting cover as a light diffuser is provided to cover a plurality of LED chips arranged on a substrate, but if the light diffusion by the light diffuser is insufficient, it may be The LED chip can be seen through the lighting cover, and the appearance is poor. Therefore, higher light diffusivity is required for the light diffuser for lighting fixtures using LEDs as light sources than for the light diffuser for lighting fixtures using fluorescent lamps or incandescent lamps as light sources.

For example, Patent Document 1 discloses an LED light source composed of a methacrylic resin composition comprising a polymer (A), a particulate inorganic compound (B) and a particulate crosslinked resin (C). In the light diffusion plate, the polymer (A) is formed by polymerizing a monomer mainly composed of methyl methacrylate.

The light diffusion plate for LED light sources disclosed in this Patent Document 1 has high light transmittance and light diffusivity, so in lighting fixtures using LEDs as light sources, the light from the LEDs can be sufficiently diffused to prevent the light from being transmitted. The light diffusion plate sees the state of the LED chips, and sufficiently transmits light from the LEDs.

prior art literature

patent documents

Patent Document 1: Japanese Unexamined Patent Publication No. 2010-77179

Contents of the invention

The problem to be solved by the invention

However, the lighting covers (light diffusers) of lighting fixtures used in homes such as chandeliers are required to be thinner and lighter so that users can easily detach them. In addition, lighting covers of lighting fixtures used in houses are required to have sufficient light resistance to light from the outside such as ultraviolet rays so that they can be used for a long period of time.

However, the light-diffusing plate for LED light sources disclosed in Patent Document 1 exhibits sufficient light-diffusing properties at a thickness of 3 mm, but cannot exhibit sufficient light-diffusing properties when it is thinner than 3 mm. Moreover, the light-diffusion plate for LED light sources disclosed by patent document 1 is easily discolored under the influence of ambient light, such as an ultraviolet-ray, and is inferior to light resistance.

This invention was made in view of the said situation, and an object of this invention is to provide the light-diffusion body which can ensure sufficient translucency, light diffusivity, and light resistance, and can reduce thickness.

solutions to problems

The light diffuser of the present invention is characterized in that it is formed of a light diffusing resin composition in which resin particles and an inorganic compound are dispersed in a base resin, and the resin particles are composed of a (meth)acrylic monofunctional monomer Polymer particles with a volume average particle diameter of 2 to 10 μm and a refractive index of 1.540 to 1.560 formed from a polymer of a monomer mixture of a multifunctional monomer, the aforementioned inorganic compound being barium sulfate with a volume average particle diameter of 0.4 to 0.7 μm, The light-diffusing resin composition contains 1.5 to 2.5 parts by weight of the resin particles relative to 100 parts by weight of the base resin, and the content ratio of the resin particles and the inorganic compound in the light-diffusing resin composition is by weight ratio , within the range of 1:0.5 to 1:1.35. However, in this specification, (meth)acrylic means methacrylic or acrylic.

The light diffuser of the present invention contains resin particles having a predetermined refractive index and a volume average particle diameter and barium sulfate having a predetermined volume average particle diameter in a predetermined ratio, and the resin particles are composed of (meth)acrylic acid Formed from a polymer of a monomer mixture of a monofunctional monomer and a polyfunctional monomer, it has excellent light transmission and light diffusing properties even at a thinner thickness (specifically, a thickness of 2mm) than before, In addition, it has excellent light resistance to light such as ultraviolet rays.

The effect of the invention

According to this invention, sufficient translucency, light diffusivity, and light resistance are ensured, and the light-diffusion body which can be thinned can be provided.

Description of drawings

FIG. 1 is a graph showing diffusivity of transmitted light in a light diffuser according to Example 1 of the present invention.

detailed description

Light diffuser of the present invention

The light diffuser of the present invention is formed by molding a light diffusing resin composition obtained by dispersing resin particles and an inorganic compound in a base resin.

The base resin is not particularly limited as long as it is a transparent resin, but is preferably a resin having a refractive index difference from the resin particles of about 0.05 to 0.07, such as an acrylic resin. Examples of the acrylic resin that can be used as the base resin include resins obtained by polymerizing methyl methacrylate as a main component. Examples of monomers that can be copolymerized with methyl methacrylate that can form the aforementioned acrylic resin include methyl acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, Esters, 2-ethylhexyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate (meth)acrylic acid esters, (meth)acrylic acid esters, diethylaminoethyl (meth)acrylate, etc., (meth)acrylic acid esters, ethylene glycol di(meth)acrylate, trimethylolpropane tri(methyl) Polyfunctional (meth)acrylates such as acrylates, allyl (meth)acrylate, and neopentyl glycol di(meth)acrylate, aromatic vinyl monomers such as styrene and α-methylstyrene Maleimides, maleimides such as phenylmaleimide and cyclohexylmaleimide, maleic anhydride, etc., but are not limited to these. However, in this specification, (meth)acrylate means methacrylate or acrylate.

The aforementioned resin particles are polymer particles formed of a polymer comprising a monomer mixture of a (meth)acrylic monofunctional monomer and a polyfunctional monomer.

The aforementioned (meth)acrylic monofunctional monomer refers to a (meth)acrylic monomer having one ethylenically unsaturated group. Examples of (meth)acrylic monofunctional monomers include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, and dodecyl acrylate. , 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, benzyl acrylate, cyclohexyl acrylate, α-methyl chloroacrylate, methyl methacrylate, methyl Ethyl acrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate ester, stearyl methacrylate, 2-chloroethyl methacrylate, phenyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, dimethylaminoethyl acrylate, dimethacrylate Methylaminoethyl, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, (Meth)acrylic esters such as 2-hydroxypropyl methacrylate and 2-hydroxybutyl methacrylate, (meth)acrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide, and methacrylamide substances, acrylic acid, methacrylic acid, etc. In the present invention, methyl methacrylate is preferable because desired light transmittance and light diffusivity can be obtained. In addition, these (meth)acrylic monofunctional monomers may be used alone or in combination of two or more.

The said polyfunctional monomer means the polyfunctional monomer which has 2 or more ethylenically unsaturated groups. Examples of the polyfunctional monomer include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol Di(meth)acrylate, Nonethylene glycol di(meth)acrylate, Tetradecyl glycol di(meth)acrylate, Decyl glycol di(meth)acrylate, Pentadecyl glycol di(meth)acrylate, Pentaethylene glycol Di(meth)acrylate, propylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate ) acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, allyl methacrylate, glycerol di(meth)acrylate, Trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, diethylene glycol di(meth)acrylate phthalate, caprolactone-modified dipentaerythritol hexa(meth)acrylate Acrylate, caprolactone-modified hydroxypivalate neopentyl glycol diacrylate, polyester acrylate, urethane acrylate and other (meth)acrylate polyfunctional monomers; divinylbenzene, Divinyl naphthalene, diallyl phthalate and their derivatives aromatic vinyl polyfunctional monomers. Among these polyfunctional monomers, (meth)acrylate-based polyfunctional monomers are preferably used. When a (meth)acrylate-type polyfunctional monomer is used as a polyfunctional monomer, the improvement of light resistance can be aimed at in the said light diffuser. In the present invention, these polyfunctional monomers may be used alone or in combination of two or more.

The content of the polyfunctional monomer in the monomer mixture is not particularly limited as long as it is a content capable of achieving a refractive index of 1.540 to 1.560 of the resin particles obtained by polymerizing the monomer mixture. The aforementioned monomer mixture is preferably 0.5 to 50 parts by weight, more preferably 3 to 30 parts by weight. When the content of the polyfunctional monomer in the monomer mixture is less than 0.5 parts by weight relative to 100 parts by weight of the monomer mixture, the resin particles obtained by polymerizing the monomer mixture may not have sufficient heat resistance. There is a concern that the resin particles may dissolve when melted and kneaded in the base resin. On the other hand, when the content of the polyfunctional monomer in the monomer mixture exceeds 50 parts by weight relative to 100 parts by weight of the monomer mixture, the heat resistance of the resin particles corresponding to the content of the polyfunctional monomer cannot be obtained. There is a concern that the cost will increase because of the improvement effect of sex.

The above-mentioned monomer mixture may contain only the above-mentioned (meth)acrylic monofunctional monomers and polyfunctional Monomers As monomers, other monomers other than the above-mentioned (meth)acrylic monofunctional monomers and polyfunctional monomers may be included. For example, if the above-mentioned monomer mixture contains a styrene-based monofunctional monomer in addition to a (meth)acrylic monofunctional monomer and a polyfunctional monomer, it is possible to obtain a polymer with a refractive index of 1.540 to 1.560 at low cost. object particles.

The aforementioned styrene-based monofunctional monomer refers to a styrene-based monomer having one ethylenically unsaturated group. As the aforementioned styrenic monofunctional monomer, any of styrene and substituted styrene (substituents include lower alkyl groups, halogen atoms (especially chlorine atoms) and the like) can be used. Specifically, usable styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene , p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, p-methoxystyrene , p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, α-methylstyrene, etc. In the present invention, styrene is preferable because desired light transmittance and light diffusibility can be obtained. In addition, these styrene-type monofunctional monomers may be used individually or in combination of 2 or more types.

It should be noted that, with regard to the content ratio of the aforementioned styrenic monofunctional monomer and the aforementioned (meth)acrylic monofunctional monomer in the aforementioned monomer mixture, as long as it can realize the formation of a polymer from the monomer mixture, The ratio of the refractive index of the polymer particles (resin particles) to 1.540 to 1.560 is not particularly limited.

The aforementioned resin particles used in the present invention can be produced by polymerizing the aforementioned monomer mixture by a known polymerization method. As a specific polymerization method, solution polymerization, suspension polymerization, seed polymerization, etc. are mentioned. Here, when the resin particles are produced by polymerizing the above-mentioned monomer mixture by seed polymerization, the resin particles may contain arbitrary components derived from seeds as long as they do not affect desired physical properties. In addition, by using these manufacturing methods, the ratio of each monomer component in a resin particle becomes a desired ratio (the compounding ratio of a monomer component).

The volume average particle diameter of the said resin particle used by this invention exists in the range of 2-10 micrometers, Preferably it exists in the range of 2-8 micrometers. When the volume average particle diameter of the said resin particle is less than 2 micrometers, sufficient translucency may not be acquired in a light diffuser, and when it exceeds 10 micrometers, sufficient light diffusivity may not be acquired in a light diffuser.

Moreover, although the coefficient of variation (CV value) of the particle diameter of the said resin particle used by this invention is not specifically limited, Preferably it is 20-50%, More preferably, it is 25-40%. If the CV value of the above-mentioned resin particles is 25 to 40%, the content ratio from particles with small particle diameters to particles with large particle diameters is appropriate, and for light diffusers, sufficient total light transmittance can be ensured, and light diffusion can be further improved. sex.

Moreover, the refractive index of the said resin particle used by this invention exists in the range of 1.540-1.560, More preferably, it exists in the range of 1.545-1.555. When the refractive index of the above-mentioned resin particles is less than 1.540, there may be a possibility that sufficient light diffusibility cannot be obtained in the light diffuser, and when it exceeds 1.560, the light diffuser may be thinned (specifically, when it is made into a thickness of 2 mm) There is a concern that sufficient light transmission and light resistance cannot be obtained.

Moreover, in this invention, content of the said resin particle with respect to the said base resin in the said light diffusing resin composition is 1.5-2.5 weight part with respect to 100 weight part of said base resins, More preferably, it is 1.5-2.0 weight part. share. When content of the said resin particle is less than 1.5 weight part with respect to 100 weight part of said base material resins, sufficient translucency and light diffusivity may not be acquired in a light diffuser. Moreover, when content of the said resin particle exceeds 2.5 weight part with respect to 100 weight part of said base resins, there exists a possibility that the light resistance of the light-diffusion body which consists of a light-diffusion resin composition may worsen.

In addition, in the present invention, barium sulfate having a volume average particle diameter of 0.4 to 0.7 μm, preferably 0.5 to 0.62 μm is used as the inorganic compound. When the particle size of the barium sulfate used as the above-mentioned inorganic compound is less than 0.4 μm, when the light diffuser is thinned (specifically, when it is made into a thickness of 2 mm), there is a possibility that sufficient light transmission cannot be obtained. When it exceeds 0.7 μm, when the light diffuser is thinned (specifically, when it is made into a thickness of 2 mm), there is a possibility that sufficient light diffusivity cannot be obtained, and there is a problem with light diffusivity and light transmittance in the light diffuser. Worries about poor balance.

In the present invention, the CV value of barium sulfate used as the aforementioned inorganic compound is not particularly limited, but is preferably 50 to 70%, more preferably 55 to 70%. If the CV value of the above-mentioned barium sulfate is 50 to 70%, the content ratio from particles with small particle diameters to particles with large particle diameters is appropriate, and for the light diffuser of the present invention, sufficient total light transmittance can be ensured, and more Improve light diffusivity.

In the present invention, the specific surface area of barium sulfate used as the aforementioned inorganic compound is preferably within a range of 3 to 5 m ² /g, more preferably within a range of 3 to 4 m ² /g. When the specific surface area of barium sulfate is in the range of 3 to 5 m ² /g, sufficient total light transmittance can be secured and light diffusivity can be further improved in the light diffuser of the present invention.

Moreover, in this invention, content of barium sulfate with respect to the said resin particle in the said light diffusing resin composition is 0.5-1.35 weight part with respect to 1 weight part of said resin particle, Preferably it is 0.6-1.33 weight part. That is, in this invention, the content ratio of the said resin particle and barium sulfate (inorganic compound) in the said light-diffusing resin composition exists in the range of 1:0.5-1:1.35 by weight ratio. When content of barium sulfate in the said light-diffusing resin composition is less than 0.5 weight part with respect to 1 weight part of said resin particles, sufficient light-diffusing property may not be acquired in a light-diffusion body. Moreover, when content of barium sulfate in the said light diffusing resin composition exceeds 1.35 weight part with respect to 1 weight part of said resin particles, sufficient total light transmittance may not be ensured in a light diffuser.

In addition, the content of barium sulfate in the light-diffusing resin composition relative to the base resin is not particularly limited, but is preferably 1.0 to 2.5 parts by weight, more preferably 1.5 to 2.5 parts by weight, based on 100 parts by weight of the base resin. . When the content of barium sulfate in the light-diffusing resin composition is in the range of 1.0 to 2.5 parts by weight relative to 100 parts by weight of the base resin, sufficient light transmittance and light resistance of the light diffuser can be ensured, and further improved Light diffusivity.

Moreover, in the light diffuser of this invention, it is preferable that the said light-diffusion resin composition contains a rubber component. By making the said light diffusing resin composition contain a rubber component, the intensity|strength of a light diffuser can be improved. Examples of the rubber component that can be used in the present invention include core-shell rubber particles, cross-linked acrylonitrile butadiene rubber particles, cross-linked styrene butadiene rubber particles, acrylic rubber particles, and the like. Core-shell type rubber particles are rubber particles having a core and a shell, for example, particles with a double-layer structure in which the outer shell is made of a glassy polymer and the inner core is made of a rubbery polymer, or the outer shell is made of a glassy polymer. The shell layer of the layer is composed of a glassy polymer, the middle layer is made of a rubbery polymer, and the core layer is made of a three-layered particle of a glassy polymer. The glass layer is made of, for example, a methyl methacrylate polymer, and the rubbery polymer layer is made of, for example, a butyl acrylate polymer (butyl rubber). These rubber components (rubber particles) may be used alone or in combination of two or more. Specific examples of the aforementioned core-shell rubber particles include "STAFILOID (registered trademark) AC3832" and "STAFILOID (registered trademark) AC3816N" manufactured by Ganz Chemical Industry Co., Ltd., and the like. Specific examples of the crosslinked acrylonitrile butadiene rubber (NBR) particles include "XER-91" (average particle diameter: 0.5 μm) manufactured by JSR Corporation. Specific examples of the crosslinked styrene butadiene rubber (SBR) particles include “XSK-500” (average particle diameter: 0.5 μm) manufactured by JSR Corporation. Specific examples of the aforementioned acrylic rubber particles include "METABLEN (registered trademark) W-300A" (average particle diameter: 0.1 μm) and "METABLEN (registered trademark) W450A" (average particle diameter: 0.2μm), etc. Among the aforementioned rubber components, the aforementioned acrylic rubber particles are preferred from the viewpoint of transparency when kneaded into the base resin (for example, acrylic resin). The average particle size of the rubber component is preferably in the range of 0.005 to 0.3 μm, more preferably in the range of 0.05 to 0.3 μm, from the viewpoint of transparency when kneaded into the base resin (for example, acrylic resin).

Moreover, it is preferable that it is 1-10 weight part with respect to 100 weight part of said base resins, and, as for content of the rubber component in the said light diffusing resin composition, it is more preferable that it is 2-5 weight part. When the content of the rubber component is less than 1 part by weight relative to 100 parts by weight of the base resin, there is a possibility that the strength of the light diffuser cannot be sufficiently improved, and when it is more than 10 parts by weight, the light transmittance of the light diffuser may decrease. worry.

In addition, in the light diffuser of the present invention, the light diffusing resin composition may contain a small amount of other resin components as long as desired physical properties such as light transmittance, light diffusivity, and light resistance are not affected. For example, various components, such as a fluorescent whitening agent, a heat stabilizer, a ultraviolet absorber, and an antistatic agent, may be contained in the said light-diffusing resin composition. In the present invention, these various components can impart desired physical properties such as fluorescent whitening property, thermal stability, and ultraviolet absorbing property to the light-diffusing resin composition.

In the present invention, the fluorescent whitening agent is not particularly limited, and for example, oxazole-based fluorescent whitening agents (for example, "Kayalight (registered trademark) OS" manufactured by Nippon Kayaku Co., Ltd.), imidazole-based fluorescent whitening agents, , Rhodamine (rhodamine) fluorescent whitening agent. In the light-diffusing resin composition, such a resin is contained in a ratio of preferably 0.0005 to 0.1 parts by weight, more preferably 0.001 to 0.1 parts by weight, and still more preferably 0.001 to 0.05 parts by weight, based on 100 parts by weight of the aforementioned base resin. In the case of a fluorescent whitening agent, fluorescent whitening properties can be provided to the light-diffusing resin composition.

In the present invention, as a heat stabilizer, there is no particular limitation, for example, organophosphorus heat stabilizers such as phosphoric acid esters, phosphites, and phosphonates can be used; hindered phenolic heat stabilizers; lactone heat stabilizers; A phosphite oxidation inhibitor having a thermal oxidation function (for example, "ADEKASTAB (registered trademark) PEP-36" manufactured by ADEKA Corporation) and the like. In the light-diffusing resin composition, such a compound is preferably contained in a ratio of 0.005 to 0.5 parts by weight, more preferably 0.01 to 0.5 parts by weight, and still more preferably 0.001 to 0.3 parts by weight, based on 100 parts by weight of the base resin. In the case of a thermal stabilizer, thermal stability can be provided to a light-diffusion resin composition.

In the present invention, the ultraviolet absorber is not particularly limited, and for example, benzophenone-based ultraviolet absorbers and benzotriazole-based ultraviolet absorbers (for example, "ADEKASTAB (registered trademark) LA-31" manufactured by ADEKA Corporation) can be used. ), hydroxyphenyl triazine UV absorbers, etc. In the light-diffusing resin composition, such a resin is contained in a ratio of preferably 0.01 to 2.0 parts by weight, more preferably 0.03 to 2.0 parts by weight, and still more preferably 0.05 to 1.0 parts by weight, based on 100 parts by weight of the base resin. In the case of an ultraviolet absorber, ultraviolet absorptivity can be imparted to the light-diffusing resin composition.

In the present invention, the antistatic agent is not particularly limited, and any of exudative antistatic agents that bleed out to exhibit antistatic performance and permanent antistatic agents that permanently exhibit antistatic performance without exudation can be used.

It does not specifically limit as said exudation-type antistatic agent, For example, cationic, anionic, betaine (zwitterionic), and nonionic surfactants are mentioned. Among these surfactants, alkylbenzenesulfonates, alkylsulfonates, and glycerin fatty acid esters are preferable. As an alkyl sulfonate, "Electrostripper (registered trademark) PC" by Kao Corporation is mentioned, for example, As glycerol fatty acid ester, "DASPERK200" by Miyoshi Yushi Co., Ltd. is mentioned, for example. Such surfactants (bleeding antistatic agents) may be used alone or in combination of two or more. When such a surfactant (bleeding type antistatic agent) is contained in a ratio of 0.1 to 3 parts by weight, more preferably 0.5 to 1.5 parts by weight, relative to 100 parts by weight of the aforementioned base resin, it is possible to impart light-diffusing properties to the resin combination. sufficient antistatic properties without discoloring the light-diffusing resin composition.

In addition, the above-mentioned permanent antistatic agent is not particularly limited, but from the viewpoint of obtaining permanent antistatic performance by adding a small amount, a block copolymer composed of a hydrophilic block and a hydrophobic block is preferable.

A block copolymer composed of a hydrophilic block and a hydrophobic block means that the hydrophilic block and the hydrophobic block are connected through an ester bond, an imide bond, an amide bond, an ether bond, or a urethane bond. Copolymers in which equibonds are alternately bonded, polyolefin etc. as the hydrophobic block, polyether, polyether-containing hydrophilic polymers, cationic polymers, and the like are exemplified as the hydrophilic block. Anionic polymers, etc.

As the polyether as the hydrophobic block, polyether diol, polyether diamine, and modified products thereof can be used. For the polyether-containing hydrophilic polymer as the hydrophobic block, polyether ester amides with polyether diol segments, polyether amides also with polyether diol segments can be used as polyether segment forming components. Imines, polyetheresters likewise with polyetherdiol segments, polyetheramides likewise with polyetherdiamine segments, polyetherurethanes likewise with polyetherdiol or polyetherdiamine segments. As the cationic polymer of the hydrophobic block, a cationic polymer having a cationic group in the molecule can be used. As said cationic group, the group which has a quaternary ammonium salt and a phosphonium salt is mentioned. For the anionic polymer as the hydrophobic block, an anionic polymer with 2 to 80 sulfonic acid groups in the molecule can be used, which has dicarboxylic acid with sulfonic acid group and diol or polyether as essential constituent units. polymer etc.

As a specific example of a block copolymer composed of a hydrophilic block and a hydrophobic block as described above, Sanyo Chemical Co., Ltd. is a block copolymer having a polyether block and a polyolefin block in the molecule. "PELESTAT (registered trademark) 230" (refractive index 1.50) manufactured by Kogyo Co., Ltd.

In the light-diffusing resin composition, when the above-mentioned permanent antistatic agent is contained in a ratio of preferably 2 to 20 parts by weight, more preferably 5 to 15 parts by weight, relative to 100 parts by weight of the aforementioned base resin, it can Permanently impart sufficient antistatic performance to the light-diffusing resin composition.

The light diffuser of the present invention is not limited by its production method, and it is preferable that the aforementioned base resin, the aforementioned resin particles, the aforementioned inorganic compound, and other additives (for example, fluorescent whitening agent, heat stabilizer, A light-diffusing resin composition obtained by mixing and kneading a predetermined amount of an ultraviolet absorber, an antistatic agent, etc.) is molded by extrusion molding to manufacture. The aforementioned mixing and kneading can utilize, for example, a ribbon mixer, a Henschel mixer, a Banbury mixer, a drum tumbler, a single-screw extruder, a twin-screw extruder, or a multi-screw extruder. The machine is waiting to proceed. The temperature condition for the aforementioned kneading is generally 240 to 300°C and is suitable. Then, the mixture obtained by mixing and kneading is molded into pellets by extrusion molding to obtain a pellet-shaped light-diffusing resin composition, and the pellet-shaped light-diffusing resin composition is extrusion-molded into a plate shape. , thereby obtaining a plate-shaped light diffuser (light diffuser plate). Alternatively, the light-diffusing resin composition obtained by mixing and kneading can be formed into a plate shape by extrusion molding to obtain a plate-shaped light diffuser (light-diffusing plate). Furthermore, the light-diffusion body of various shapes can be obtained by vacuum-forming, pressure-press forming, etc. the said plate-shaped light-diffusion body (light-diffusion plate).

The light diffuser of the present invention exhibits a total light transmittance of preferably 55% or more, more preferably 55 to 65%, and a dispersion of preferably 55° or more, more preferably 55 to 60°, when the thickness is 2 mm . In addition, when the light diffuser of the present invention has a thickness of 2 mm, the color difference after 200 hours of exposure (Hunter value ΔE) obtained by the method for measuring the color difference after accelerated exposure described later is preferably less than 3, more preferably less than 1.

This light diffuser of the present invention has a thin thickness (specifically, when the thickness is 2 mm), and shows high total light transmittance and dispersion, for example, it can be used as a lighting fixture with an LED light source (for example, a general lighting device) , illuminated displays, and illuminated billboards, etc.) can fully diffuse the light from the LED light source when used as a light diffuser. Furthermore, it has excellent light resistance, and has high durability as a light diffuser for at least indoor lighting fixtures. In addition, the above-mentioned light diffuser with a small color difference (Hunter value ΔE) after 200 hours of exposure, for example, a light diffuser with a color difference (Hunter value ΔE) of less than 1, can be used not only for indoor use but also for outdoor use. The light diffuser for lighting fixtures also has high durability.

The thickness of the light diffuser of this invention is not specifically limited, By setting it as 1.0-3.0 mm, More preferably, it is 1.4-2.0 mm, Excellent light diffusivity, translucency, and light resistance can be exhibited.

The light diffuser of this invention can be used as a lighting cover which covers a light source in the lighting fixture which uses various light sources, such as a fluorescent lamp and a light emitting diode (LED), for example. The shape of the light diffuser of this invention is not specifically limited, According to the use, it can be made into various shapes. For example, when the light diffuser of the present invention is used as a lighting cover, the shape of the light diffuser may be a semicylindrical shape, a flat plate shape, or a dome shape.

Example

The physical properties of the light diffuser according to the examples of the present invention will be described in detail below.

First, the method for measuring the volume average particle diameter of the resin particles and barium sulfate used to manufacture the light diffuser of the embodiment of the present invention, the calculation method of the coefficient of variation (CV value) of the particle diameters of the resin particles and barium sulfate, The method of measuring the specific surface area of barium sulfate, the method of measuring the refractive index of resin particles, and the method of measuring the color difference after accelerated exposure will be described.

Method for Determination of Volume Average Particle Size of Resin Particles

The volume average particle diameter of the polymer particles is calculated by the following method: fill pores with a pore diameter of 20 to 400 μm with an electrolyte solution, obtain the volume from the change in conductivity of the electrolyte solution when the particles pass through the electrolyte solution, and calculate the volume average particle size. particle size. Specifically, the volume average particle diameter of the resin particles is the volume average particle diameter (arithmetic average diameter of the volume-based particle size distribution) measured using a Coulter method precision particle size distribution measuring device "Multisizer III" (manufactured by Beckman Coulter, Inc.). However, in the measurement, according to "Reference MANUAL FORTHE COULTER MULTISIZER" (1987) issued by Coulter Electronics Limited, the Multisizer III was calibrated and measured using an aperture (aperture) suitable for the particle diameter of the particles to be measured.

Specifically, 0.1 g of resin particles was dispersed in 10 ml of a 0.1% by weight nonionic surfactant solution using a contact mixer and ultrasonic waves to prepare a dispersion. Into the beaker filled with the measurement electrolyte solution "ISOTON (registered trademark) II" (manufactured by Beckman Coulter, Inc.) installed on the main body of "Multisizer III", add the above-mentioned dispersion liquid dropwise with a dropper while stirring slowly, and the main screen of "Multisizer III" The reading of the concentration meter is around 10%. Then, input aperture (diameter, aperture size), Current (aperture current, aperture current), Gain (gain), Polarity (polarity of the inner electrode) to the "MultisizerIII" main body according to REFERENCE MANUAL FORTHE COULTER MULTISIZER (1987) issued by Coulter Electronics Limited, and use manual (manual mode) to determine the particle size distribution on a volume basis. During the measurement, the beaker was stirred slowly so as not to mix air bubbles in the beaker, and the measurement was terminated when the particle size distribution of 100,000 particles was measured. The volume-average particle diameter of the resin particles is the average value of the particle diameters of 100,000 particles measured, and refers to the arithmetic mean diameter of the particle size distribution based on the volume.

Determination method of volume average particle diameter of barium sulfate

The volume average particle diameter of barium sulfate (the arithmetic mean diameter of the particle size distribution based on the volume) was measured with a laser diffraction scattering particle size distribution analyzer (manufactured by Beckman Coulter, Inc., "LS13320 type"). Specifically, 0.1 g of barium sulfate and 10 ml of a 1% by weight sodium pyrophosphate aqueous solution were put into a test tube, and mixed for 2 seconds with a contact mixer (manufactured by Yamato Scientific Co., Ltd., "TOUCHMIXERMT-31"). Then, the barium sulfate in the test tube was dispersed for 10 minutes with a commercially available ultrasonic cleaner (manufactured by VELVO-CLEAR, "ULTRASONICCLEANER VS-150") to obtain a dispersion liquid. While irradiating the dispersion liquid with ultrasonic waves, the volume average particle diameter (arithmetic mean diameter of the particle size distribution based on the volume) of the barium sulfate in the dispersion liquid was measured with the above-mentioned laser diffraction scattering particle size distribution measuring device. The optical model at the time of this measurement agrees with the measured refractive index (1.64) of barium sulfate.

Calculation method of CV value of resin particles and barium sulfate

The respective CV values of the resin particles and barium sulfate were calculated from the standard deviation (σ) and the volume average particle diameter (x) when the volume-based particle size distribution was measured, according to the following mathematical formula.

CV value (%) = (σ/x) × 100

Determination method of specific surface area of barium sulfate

The specific surface area of barium sulfate is measured by the BET method (nitrogen adsorption method) described in JISR1626. For barium sulfate as a measurement object, the BET nitrogen adsorption isotherm was measured using an automatic specific surface area/pore distribution measuring device Tristar 3000 manufactured by Shimadzu Corporation, and the specific surface area was calculated from the amount of nitrogen adsorption by the BET multipoint method. Wherein, the measurement of the nitrogen adsorption isotherm uses nitrogen as an adsorbate, and is carried out by a constant volume method under the condition that the cross-sectional area of the adsorbate is 0.162 nm ² .

Method for Measuring Refractive Index of Resin Particles

The measurement of the refractive index of the resin particle was performed by the Beck method. In this measurement of the refractive index by the Baker method, resin particles are placed on a glass slide, and a refraction solution (manufactured by CARGILLE Corporation: CARGILLE standard refraction solution, a plurality of refraction samples with a refraction index of 1.538 to 1.562 are prepared at intervals of 0.002, respectively, is prepared dropwise. liquid). Next, after the resin particles and the refraction liquid were well mixed, the profile of the particles was observed from above with an optical microscope while irradiating light from a high-pressure sodium lamp (model "NX35", center wavelength 589 nm) manufactured by Iwasaki Electric Co., Ltd. from below. Then, when no outline is seen, it is judged that the refractive index of the refractive liquid and the resin particles are equal.

Among them, there is no problem in observation with an optical microscope as long as the observation is performed at a magnification at which the outline of the resin particles can be confirmed. However, for particles with a particle diameter of 5 μm, observation at a magnification of about 500 times is appropriate. According to the above-mentioned operation, the closer the refractive index of the resin particle and the refraction liquid is, the more difficult it is to observe the outline of the resin particle. equal.

In addition, when there is no difference in the visibility of the resin particles between the two types of refraction liquids with a difference in refractive index of 0.002, the intermediate value of the refractive indices of the two types of refraction liquids is used as the refractive index of the resin particles. For example, when testing with refraction liquids with a refractive index of 1.554 and 1.556, and there is no difference in the visibility of the resin particles in the two refraction liquids, the intermediate value of the refractive index of these refraction liquids, 1.555, is determined as the refractive index of the resin particles.

Next, the measuring method of the total light transmittance and dispersion degree of the light diffuser which concerns on the Example of this invention is demonstrated. However, in the measurement of the total light transmittance and degree of dispersion, a plate-shaped light diffuser (light diffuser plate) having a thickness of 2 mm and 50 mm×100 mm obtained in Examples and Comparative Examples described later was used as a measurement object.

Method for Determination of Total Light Transmittance of Light Diffusers

The total light transmittance of a light diffuser is measured based on JISK7361. Specifically, the total light transmittance was measured using "NDH-4000" manufactured by Nippon Denshoku Industries Co., Ltd. The number of measurement samples was set to n=10, the average value of the total light transmittance (%) of these 10 measurement samples was calculated, and this average value was taken as the total light transmittance (%) of the light diffuser.

Method for Determination of Dispersion Degree of Light Diffuser

The degree of dispersion (D50) of the light diffuser was determined by the following procedure using an automatic goniophotometer (Goniophotometer GP-200 manufactured by Murakami Color Technology Laboratory).

Direct rays from the light source of the automatic goniophotometer were irradiated from the normal direction of the light diffuser installed at a distance of 75 cm from the light source. The intensity of light passing through the light diffuser is measured with a movable photoreceptor. This intensity was converted into a transmittance, and the transmittance was plotted on the graph corresponding to the angle from the normal direction. From this figure, the angle at which the transmittance of light in the normal direction (direct light transmittance) reaches a transmittance of 50% is obtained. This angle is called dispersion (D50). The unit of the degree of dispersion (D50) is "° (degree)". In addition, a larger degree of dispersion (D50) means better diffusibility.

Next, the measuring method of the color difference after the accelerated exposure of the light diffuser which concerns on the Example of this invention is demonstrated. However, in the measurement of the color difference after the accelerated exposure, a plate-shaped light diffuser (light diffuser plate) having a thickness of 2 mm and 50 mm×100 mm obtained in Examples and Comparative Examples described later was used as a test piece.

Method for Determination of Color Difference After Accelerated Exposure

First, the Hunter value (E ₀ ) of the test piece was measured by the color measurement method shown below. Next, the accelerated exposure test shown below was performed, and the Hunter value (E ₁ ) of the test piece after the accelerated exposure test was measured by the color measurement method shown below. Then, the difference (E ₁ -E ₀ ) between the Hunter value (E ₀ ) of the test piece before the accelerated exposure test and the Hunter value (E ₁ ) of the test piece after the accelerated exposure test was used as the color difference after the accelerated exposure ( Hunter ΔE value).

Facilitated Exposure Trials

The accelerated exposure test of the light diffuser was performed in accordance with JIS K7350-2 (Plastic-Exposure test method by laboratory light source-Part 2: Xenon arc lamp). Specifically, the test piece was exposed to a xenon arc lamp for 200 hours under the following test conditions.

Test conditions

Irradiation device: SuperXenon WeatherMeter-SX75 type (manufactured by SugaTestInstruments Co., Ltd.)

Irradiation conditions: black panel temperature (63°C), no switching during darkness, no spray (spray), OuterFilter#275

Wavelength range: 300~400nm

Irradiance: 180W/m ²

Test piece: thickness 2mm, 50mm×100mm

Test tank: temperature (28-32°C), humidity (45-55%)

Method of Determination of Color

The measurement of color is carried out in accordance with JISZ8722 (method of measuring color-reflected and transmitted object color). Specifically, under the following measurement conditions, the color of the test piece was measured on a white board dedicated to reference pressing, and the Hunter value was obtained.

Measurement conditions

Measuring device: spectroscopic color meter SE-2000 (manufactured by Nippon Denshoku Kogyo Co., Ltd.)

Color management software: ColorMate5 (manufactured by Nippon Denshoku Kogyo Co., Ltd.)

Tristimulus value (C/2) of the standard plate: Y=96.09, X=94.13, Z=113.36

Dedicated whiteboard for reference pressing: Y=76.5, X=75.4, Z=84.6

Measuring method: reflection method

Light source: Determination of C/2° field of view conditions

Next, the manufacturing method of the resin particle (A) and the resin particle (B) for manufacturing the light-diffusion body of Examples 1-6 of this invention is demonstrated.

Method for producing resin particles (A)

3000 g of pure water, 1.5 g of sodium lauryl sulfate (500 ppm), and 90 g of magnesium pyrophosphate were put into a stainless steel beaker with a volume of 5 L to prepare an aqueous phase.

400 g of methyl methacrylate as a (meth)acrylic monofunctional monomer, 500 g of styrene as a styrene monofunctional monomer, 100 g Divinylbenzene (DVB) as a polyfunctional monomer, 3 g of n-dodecylmercaptan as a chain transfer agent, 7 g of 2,2-azobis-(2,4-dimethyl valeronitrile), 4g of tert-butylperoxy-2-ethylhexyl, and fully stirred to prepare the oil phase.

The prepared oil phase was added to the previously prepared water phase, and stirred at 8000 rpm for 15 minutes using a TK homomixer manufactured by PRIMIX Corporation to obtain a suspension. Next, the obtained suspension was transferred to a reactor with a capacity of 5 L equipped with a stirrer and a thermometer, and after polymerizing the monomer (monomer) at 60° C. for 5 hours, it was heated at 110° C. for 2 hours, and then cooled to 30° C. °C to obtain resin particle slurry. Next, hydrochloric acid is added to the resin particle slurry until the pH of the slurry is 2 or less. Then, the resin particle slurry to which perhydrochloric acid was added was washed using a centrifugal dehydrator until the pH of the washing water was 6 to 7, and dehydration was performed thereafter. The dehydrated cake thus obtained was vacuum-dried at a jacket temperature of 60° C. for 20 hours using a vacuum dryer. Next, it was passed through a 400-mesh sieve to obtain resin particles (A).

The volume average particle diameter of this resin particle (A) was measured by the above-mentioned measurement method, and it was 5.4 micrometers. In addition, the CV value of the resin particle (A) was calculated to be 37.9% by the calculation method described above. Moreover, when the refractive index of this resin particle (A) was measured by the said measuring method, it was 1.555.

Method for producing resin particles (B)

Resin particles (B) were obtained in the same manner as the production method of the above-mentioned resin particles (A) except that the usage-amount of methyl methacrylate was 550 g and the usage-amount of styrene was 350 g. The volume average particle diameter of this resin particle (B) was measured by the above-mentioned measurement method, and it was 5.8 micrometers. In addition, the CV value of the resin particle (B) was calculated by the calculation method described above, and it was 33.9%. Moreover, when the refractive index of this resin particle (B) was measured by the said measuring method, it was 1.540.

Next, the manufacturing method of the resin particle (C) used for manufacturing the light-diffusion body of the comparative example 1 mentioned later, and the resin particle (D) used for manufacture of the light-diffusion body of the comparative example 10 is demonstrated.

Manufacturing method of resin particles (C)

Resin particles (C) were obtained in the same manner as the production method of the above-mentioned resin particles (A) except that methyl methacrylate was not used and the amount of styrene used was 900 g. The volume average particle diameter of this resin particle (C) was measured by the above-mentioned measurement method, and it was 5.6 micrometers. In addition, the CV value of the resin particle (C) calculated by the above-mentioned calculation method was 38.2%. Moreover, when the refractive index of this resin particle (C) was measured by the said measuring method, it was 1.592.

Manufacturing method of resin particle (D)

3000 g of pure water, 1.5 g of sodium lauryl sulfate (500 ppm), and 90 g of magnesium pyrophosphate were put into a stainless steel beaker with a volume of 5 L to prepare an aqueous phase.

950 g of methyl methacrylate as a (meth)acrylic monofunctional monomer and 50 g of ethylene glycol dimethacrylic acid as a polyfunctional monomer were placed in a stainless steel beaker different from the stainless steel beaker used for the preparation of the water phase. Ester (EGDMA), 3g of n-dodecylmercaptan as chain transfer agent, 7g of 2,2-azobis-(2,4-dimethylvaleronitrile) as polymerization initiator, 4g of tert-butyl peroxide Oxygen-2-ethylhexyl ester was stirred well to prepare the oil phase.

The prepared oil phase was added to the previously prepared water phase, and stirred at 8000 rpm for 15 minutes using a TK homomixer manufactured by PRIMIX Corporation to obtain a suspension. Next, the obtained suspension was transferred to a reactor with a capacity of 5 L equipped with a stirrer and a thermometer, and after polymerizing the monomer (monomer) at 50° C. for 5 hours, it was heated at 105° C. for 2 hours, and then cooled to 30° C. °C to obtain resin particle slurry. Next, hydrochloric acid is added to the resin particle slurry until the pH of the slurry is 2 or less. Then, the resin particle slurry to which perhydrochloric acid was added was washed using a centrifugal dehydrator until the pH of the washing water was 6 to 7, and dehydration was performed thereafter. The dehydrated cake thus obtained was vacuum-dried at a jacket temperature of 60° C. for 20 hours using a vacuum dryer. Next, it was passed through a 400-mesh sieve to obtain resin particles (D). The volume average particle diameter of this resin particle (D) was measured by the said measuring method, and it was 5.2 micrometers. In addition, the CV value of the resin particle (D) calculated by the above-mentioned calculation method was 34.2%. Moreover, when the refractive index of this resin particle (D) was measured by the said measuring method, it was 1.496.

Next, the manufacturing method of the resin particle (E)-(H) for manufacturing the light-diffusion body of Examples 7-10 of this invention is demonstrated.

Method for producing resin particles (E)

The amount of methyl methacrylate used as a (meth)acrylic monofunctional monomer was 350 g, the amount of styrene used as a styrene monofunctional monomer was 600 g, and 50 g of ethylene glycol dimethyl Resin particles (E) were obtained in the same manner as the production method of the above-mentioned resin particles (A) except that 100 g of divinylbenzene (DVB) was replaced with 100 g of divinylbenzene (DVB) as the polyfunctional monomer.

The volume average particle diameter of this resin particle (E) was measured by the above-mentioned measurement method, and it was 5.5 micrometers. In addition, the CV value of the resin particle (E) was calculated by the above calculation method, and it was 37.0%. Moreover, when the refractive index of this resin particle (E) was measured by the said measuring method, it was 1.554.

Manufacturing method of resin particle (F)

350 g of methyl methacrylate as a (meth)acrylic monofunctional monomer, 600 g of styrene as a styrene monofunctional monomer, and 50 g of trimethylolpropane Except having replaced 100 g of divinylbenzene (DVB) with trimethacrylate (TMP) as a polyfunctional monomer, it carried out similarly to the manufacturing method of the said resin particle (A), and obtained the resin particle (F).

The volume average particle diameter of this resin particle (F) was measured by the above-mentioned measurement method, and it was 5.4 micrometers. In addition, the CV value of the resin particle (F) was calculated by the above calculation method, and it was 36.5%. Moreover, when the refractive index of this resin particle (F) was measured by the said measuring method, it was 1.553.

Manufacturing method of resin particles (G)

The amount of methyl methacrylate used as a (meth)acrylic monofunctional monomer was 350 g, the amount of styrene used as a styrene monofunctional monomer was 600 g, and further 50 g of 1,6-hexanediene was used. Resin particles (G) were obtained in the same manner as the production method of the above-mentioned resin particles (A) except that alcohol dimethacrylate (1,6HX) was used instead of 100 g of divinylbenzene (DVB) as the polyfunctional monomer.

The volume average particle diameter of this resin particle (G) was measured by the above-mentioned measurement method, and it was 5.3 micrometers. In addition, the CV value of the resin particle (G) calculated by the above-mentioned calculation method was 38.9%. In addition, when the refractive index of the resin particle (G) was measured by the above-mentioned measuring method, it was 1.553.

Manufacturing method of resin particle (H)

350 g of methyl methacrylate as a (meth)acrylic monofunctional monomer, 600 g of styrene as a styrene monofunctional monomer, and 50 g of allyl methacrylate Except having replaced 100 g of divinylbenzene (DVB) with ester (AMA) as a polyfunctional monomer, it carried out similarly to the manufacturing method of the said resin particle (A), and obtained the resin particle (H).

The volume average particle diameter of this resin particle (H) was measured by the above-mentioned measuring method, and it was 5.8 μm. In addition, the CV value of the resin particle (H) calculated by the above calculation method was 39.4%. In addition, when the refractive index of the resin particle (H) was measured by the above-mentioned measuring method, it was 1.554.

The light diffusers of Examples 1 to 10 and Comparative Examples 1 to 10 of the present invention are shown below.

Example 1

100 parts by weight of acrylic resin (manufactured by Sumitomo Chemical Co., Ltd., trade name "SUMIPEX (registered trademark) EX") as a base resin, 2.5 parts by weight of acrylic rubber particles as a rubber component (manufactured by Mitsubishi Rayon Corporation, Trade name "METABLEN (registered trademark) W-300A"), 2.0 parts by weight of resin particles (A) with a refractive index of 1.555 obtained by the above production method, 2.0 parts by weight (1 part by weight to 1 part by weight of resin particles) by Barium sulfate (sedimentable barium sulfate "B55" manufactured by Sakai Chemical Industry Co., Ltd., CV value 65.9%, specific surface area 4.13g/m ² ) with a volume average particle diameter of 0.50 μm measured by the above-mentioned measurement method using a Henschel mixer Mix for 15 minutes to obtain a mixture. The mixture was extruded with a single-screw extruder ("R50" manufactured by Hoshi Plastic K.K.) at a temperature of 210 to 260°C and a discharge rate of 10 to 25kg/h, water-cooled, and cut with a pelletizer. A particulate light-diffusing resin composition was obtained. Next, the obtained granular light-diffusing resin composition was pre-dried at 105°C for 5 hours, and after fully removing moisture, it was extruded with a T-die extrusion molding machine (manufactured by Soken Co., Ltd., diameter 30mm, L/D=38 , T-shaped die width 250mm, die lip 2mm) extruded into a plate shape at a temperature of 220-260°C to obtain a light diffusion plate (light diffuser) with a thickness of 2mm. The thus obtained light-diffusing plate was cut into a width of 50 mm and a length of 100 mm, and evaluation of optical characteristics (measurement of total light transmittance and degree of dispersion) and evaluation of light resistance (measurement of color difference after accelerated exposure test) were performed.

FIG. 1 shows the results of measuring the transmitted light intensity of the light diffusing plate (light diffusing body) obtained in Example 1 with an automatic goniophotometer. The vertical axis is the relative value of the transmitted light intensity, and a vertical line is drawn from the point on the graph when the value is 50%, and the intersection with the horizontal axis is obtained. The value of this horizontal axis is the angle (°), called the degree of dispersion (D50). In the measurement results shown in FIG. 1 , the degree of dispersion (D50) was 57.3°. In addition, the degree of dispersion (D50) is the arithmetic mean value of the absolute values of the two values on the left and right of the origin of 0° on the horizontal axis (the value of the angle when the transmitted light intensity is 50%).

Example 2

With respect to 100 parts by weight of the base resin, 2.0 parts by weight (1 part by weight relative to 1 part by weight of resin particles) of barium sulfate with a volume average particle diameter of 0.62 μm (sedimentable barium sulfate manufactured by Sakai Chemical Industry Co., Ltd. B300", CV value 59.9%, specific surface area 3.4g/m ² ) instead of 2.0 parts by weight of barium sulfate with a volume average particle diameter of 0.50μm (sedimentable barium sulfate "B55" manufactured by Sakai Chemical Industry Co., Ltd., CV value 65.9 %, a specific surface area of 4.13 g/m ² ), a light diffusion plate (light diffuser) was obtained in the same manner as in Example 1 except that.

Example 3

With respect to 100 parts by weight of the base resin, 1.5 parts by weight of resin particles (A) were compounded, and 2.0 parts by weight (1.33 parts by weight relative to 1 part by weight of resin particles) of barium sulfate ( Precipitable barium sulfate "B300" manufactured by Sakai Chemical Industry Co., Ltd., CV value 59.9%, specific surface area 3.4 g/m ² ) was used instead of 2.0 parts by weight of barium sulfate with a volume average particle size of 0.50 μm (manufactured by Sakai Chemical Industry Co., Ltd. A light-diffusing plate (light-diffusing body) was obtained in the same manner as in Example 1 except that the sedimentary barium sulfate "B55" had a CV value of 65.9%, and a specific surface area of 4.13 g/m ² ).

Example 4

With respect to 100 parts by weight of the base resin, 2.5 parts by weight of resin particles (A) were compounded, and 1.5 parts by weight (0.6 parts by weight relative to 1 part by weight of resin particles) of barium sulfate ( Precipitable barium sulfate "B300" manufactured by Sakai Chemical Industry Co., Ltd., CV value 59.9%, specific surface area 3.4 g/m ² ) was used instead of 2.0 parts by weight of barium sulfate with a volume average particle size of 0.50 μm (manufactured by Sakai Chemical Industry Co., Ltd. A light-diffusing plate (light-diffusing body) was obtained in the same manner as in Example 1 except that the sedimentary barium sulfate "B55" had a CV value of 65.9%, and a specific surface area of 4.13 g/m ² ).

Example 5

With respect to 100 parts by weight of the base resin, 2.0 parts by weight (1 part by weight relative to 1 part by weight of resin particles) of barium sulfate with a volume average particle diameter of 0.62 μm (sedimentable barium sulfate manufactured by Sakai Chemical Industry Co., Ltd. B300", CV value 59.9%, specific surface area 3.4g/m ² ) instead of 2.0 parts by weight of barium sulfate with a volume average particle diameter of 0.50μm (sedimentable barium sulfate "B55" manufactured by Sakai Chemical Industry Co., Ltd., CV value 65.9 %, specific surface area 4.13g/m ² ), not compounding acrylic rubber particles (manufactured by Mitsubishi Rayon Corporation, trade name "METABLEN (registered trademark) W-300A") as a rubber component, and used in the examples 1. Obtain a light diffusion plate (light diffuser) in the same way.

Example 6

With respect to 100 parts by weight of the substrate resin, 2.5 parts by weight of resin particles (B) having a refractive index of 1.540 obtained by the above-mentioned production method was blended instead of 2.0 parts by weight of resin particles (A), and the same method as in Example 1 was used. Method Obtain a light-diffusing plate (light-diffusing body).

Example 7

With respect to 100 parts by weight of the base resin, 2.0 parts by weight of resin particles (E) having a refractive index of 1.554 obtained by the above-mentioned production method was blended instead of 2.0 parts by weight of resin particles (A), and the same method as in Example 5 was used. Method Obtain a light-diffusing plate (light-diffusing body).

Example 8

With respect to 100 parts by weight of the base resin, 2.0 parts by weight of resin particles (F) having a refractive index of 1.553 obtained by the above-mentioned production method was blended instead of 2.0 parts by weight of resin particles (A), and the same method as in Example 5 was used. Method Obtain a light-diffusing plate (light-diffusing body).

Example 9

With respect to 100 parts by weight of the base resin, 2.0 parts by weight of resin particles (G) having a refractive index of 1.553 obtained by the above-mentioned production method was blended instead of 2.0 parts by weight of resin particles (A), and the same method as in Example 5 was used. Method Obtain a light-diffusing plate (light-diffusing body).

Example 10

With respect to 100 parts by weight of the base resin, 2.0 parts by weight of resin particles (H) having a refractive index of 1.554 obtained by the above-mentioned production method was blended instead of 2.0 parts by weight of resin particles (A), and the same method as in Example 5 was used. Method Obtain a light-diffusing plate (light-diffusing body).

Comparative example 1

With respect to 100 parts by weight of the base resin, 2.0 parts by weight of resin particles (C) having a refractive index of 1.592 obtained by the above-mentioned production method were blended instead of 2.0 parts by weight of resin particles (A), and further compounded with 2.0 parts by weight (relative to 1 Parts by weight of resin particles is 1 part by weight) of barium sulfate with a volume average particle diameter of 0.62 μm (sedimentable barium sulfate "B300" manufactured by Sakai Chemical Industry Co., Ltd., CV value 59.9%, specific surface area 3.4 g/m ² ) instead 2.0 parts by weight of barium sulfate with a volume average particle diameter of 0.50 μm (sedimentable barium sulfate "B55" manufactured by Sakai Chemical Industry Co., Ltd., CV value 65.9%, specific surface area 4.13g/m ² ), in addition 1. Obtain a light diffusion plate (light diffuser) in the same way.

Comparative example 2

With respect to 100 parts by weight of the base resin, 0.7 parts by weight of resin particles (A) were compounded, and 2.2 parts by weight (3.14 parts by weight relative to 1 part by weight of resin particles) of barium sulfate ( Precipitable barium sulfate "B300" manufactured by Sakai Chemical Industry Co., Ltd., CV value 59.9%, specific surface area 3.4 g/m ² ) was used instead of 2.0 parts by weight of barium sulfate with a volume average particle size of 0.50 μm (manufactured by Sakai Chemical Industry Co., Ltd. A light-diffusing plate (light-diffusing body) was obtained by the same method as in Example 1 except that the precipitable barium sulfate "B55", CV value 65.9%, and specific surface area 4.13 g/m ² ).

Comparative example 3

With respect to 100 parts by weight of the base resin, 2.0 parts by weight (1 part by weight relative to 1 part by weight of resin particles) of barium sulfate with a volume average particle diameter of 0.34 μm (sedimentable barium sulfate manufactured by Sakai Chemical Industry Co., Ltd. B30", CV value 89.4%, specific surface area 13.84g/m ² ) instead of 2.0 parts by weight of barium sulfate with a volume average particle diameter of 0.50μm (sedimentable barium sulfate "B55" manufactured by Sakai Chemical Industry Co., Ltd., CV value 65.9 %, a specific surface area of 4.13 g/m ² ), and a light diffusion plate (light diffuser) was obtained by the same method as in Example 1 except that.

Comparative example 4

With respect to 100 parts by weight of the base resin, 0.5 parts by weight (0.25 parts by weight relative to 1 part by weight of resin particles) of barium sulfate with a volume average particle diameter of 0.62 μm (settled barium sulfate manufactured by Sakai Chemical Industry Co., Ltd. B300", CV value 59.9%, specific surface area 3.4g/m ² ) instead of 2.0 parts by weight of barium sulfate with a volume average particle diameter of 0.50μm (sedimentable barium sulfate "B55" manufactured by Sakai Chemical Industry Co., Ltd., CV value 65.9 %, a specific surface area of 4.13 g/m ² ), and a light diffusion plate (light diffuser) was obtained by the same method as in Example 1 except that.

Comparative example 5

With respect to 100 parts by weight of the base resin, 1 part by weight of resin particles (A) was compounded, and 4 parts by weight (4 parts by weight relative to 1 part by weight of resin particles) of barium sulfate ( Precipitable barium sulfate "B300" manufactured by Sakai Chemical Industry Co., Ltd., CV value 59.9%, specific surface area 3.4 g/m ² ) was used instead of 2.0 parts by weight of barium sulfate with a volume average particle size of 0.50 μm (manufactured by Sakai Chemical Industry Co., Ltd. A light-diffusing plate (light-diffusing body) was obtained by the same method as in Example 1 except that the precipitable barium sulfate "B55", CV value 65.9%, and specific surface area 4.13 g/m ² ).

Comparative example 6

No barium sulfate with a volume average particle size of 0.50 μm (sedimentable barium sulfate “B55” manufactured by Sakai Chemical Industry Co., Ltd., CV value 65.9%, specific surface area 4.13 g/m ² ) was not compounded with respect to 100 parts by weight of the base resin , except that, a light-diffusing plate (light-diffusing body) was obtained by the same method as in Example 1.

Comparative Example 7

With respect to 100 parts by weight of the base resin, 3 parts by weight of the resin particles (A) were compounded, and barium sulfate (settled barium sulfate "B55" manufactured by Sakai Chemical Industry Co., Ltd., CV value of 65.9%, and a specific surface area of 4.13 g/m ² ), a light-diffusing plate (light-diffusing body) was obtained by the same method as in Example 1.

Comparative example 8

With respect to 100 parts by weight of the base resin, 5 parts by weight of resin particles (A) were compounded, and barium sulfate with a volume average particle diameter of 0.50 μm (settled barium sulfate "B55", CV value of 65.9%, and a specific surface area of 4.13 g/m ² ), a light-diffusing plate (light-diffusing body) was obtained by the same method as in Example 1.

Comparative Example 9

With respect to 100 parts by weight of the base resin, 2.0 parts by weight of barium sulfate with a volume average particle diameter of 0.75 μm (sedimentable barium sulfate "B-1" manufactured by Sakai Chemical Industry Co., Ltd., CV value 49.4%, specific surface area 2.2 g/m ² ) instead of 2.0 parts by weight of barium sulfate with a volume average particle size of 0.50 μm (sedimentable barium sulfate "B55" manufactured by Sakai Chemical Industry Co., Ltd., CV value 65.9%, specific surface area 4.13 g/m ² ), Except for this, the light-diffusion board (light-diffusion body) was obtained by the method similar to Example 1.

Comparative Example 10

With respect to 100 parts by weight of the base resin, 2.0 parts by weight of resin particles (D) having a refractive index of 1.496 obtained by the above-mentioned production method were blended instead of 2.0 parts by weight of resin particles (A), and further compounded with 2.0 parts by weight (relative to 1 Parts by weight of resin particles is 1 part by weight) of barium sulfate with a volume average particle diameter of 0.62 μm (sedimentable barium sulfate "B300" manufactured by Sakai Chemical Industry Co., Ltd., CV value 59.9%, specific surface area 3.4 g/m ² ) instead 2.0 parts by weight of barium sulfate with a volume average particle diameter of 0.50 μm (sedimentable barium sulfate "B55" manufactured by Sakai Chemical Industry Co., Ltd., CV value 65.9%, specific surface area 4.13g/m ² ), in addition 1. Obtain a light diffusion plate (light diffuser) in the same way.

Table 1 shows the compounding amounts of various raw materials (parts by weight relative to 100 parts by weight of the base resin) of the light-diffusing resin compositions used to manufacture the light-diffusing bodies of Examples 1 to 10 and Comparative Examples 1 to 10 , the total light transmittance of the light diffusers of Examples 1-6 and Comparative Examples 1-10, the degree of dispersion (D50), and the color difference (Hunter ΔE value) after the accelerated exposure test.

Table 1

As shown in Table 1, when the light diffusers of Examples 1 to 10 of the present invention are made into a thickness of 2 mm, they show a total light transmittance of 55% or more (specifically, 55.44 to 58.30%) and a total light transmittance of 55° or more (specifically, In terms of dispersion, 55.00-57.95°), it can be considered that it shows excellent light transmittance and light diffusivity. In addition, the color difference (Hunter ΔE value) after 200 hours of accelerated exposure of the light diffusers of Examples 1 to 6 of the present invention was less than 3 (specifically, 2.5 or less), and it can be considered that the light diffusers of Examples 1 to 10 The body has practically sufficient light resistance at least for indoor lighting.

Moreover, about the light diffuser of Examples 7-10 containing any one of the resin particle (E)-(H) manufactured using (meth)acrylate polyfunctional monomer as a polyfunctional monomer, and Compared with the light diffusers of Examples 1 to 6 containing resin particles (A) or (B) produced using divinylbenzene (DVB) as a polyfunctional monomer, it promotes color difference after 200 hours of exposure (Hunter ΔE value) is smaller, and it can be considered that the light resistance is more excellent. Specifically, the color difference (Hunter ΔE value) of the light diffusers of Examples 7 to 10 after accelerated exposure for 200 hours was less than 1 (specifically, 0.6 or less), and they are not only used for indoor lighting but also have Practical light fastness for outdoor lighting.

On the other hand, the light diffuser of Comparative Example 1 produced using resin particles (C) with a refractive index of 1.592 and resin particles (A), (B) and (E) to (H) with a refractive index of 1.540 to 1.560 were used. The total light transmittance was low and the light transmittance was inferior compared with the light-diffusion body of Examples 1-10 manufactured in any of them. Moreover, the color difference after the accelerated exposure of the light diffuser of the comparative example 1 exceeded 3, and was inferior to light resistance.

In addition, regarding the comparative example 2 formed from the light-diffusing resin composition in which the content of the resin particles is 0.7 parts by weight relative to 100 parts by weight of the base resin, and the content of barium sulfate is 3.1 parts by weight relative to 1 part by weight of the resin particles The light diffuser, and the content of the resin particles is 1.5 to 2.5 parts by weight relative to 100 parts by weight of the base resin, and the content of barium sulfate is 0.5 to 1.35 parts by weight relative to 1 part by weight of the resin particles (more specifically , 0.6 to 1.33 parts by weight) compared with the light diffusers of Examples 1 to 10 formed from the light diffusing resin composition, the total light transmittance and degree of dispersion are low, and the optical properties are poor.

In addition, implementation of the production of the light diffuser of Comparative Example 3 using barium sulfate having a volume average particle diameter of 0.34 μm and using barium sulfate having a volume average particle diameter of 0.4 to 0.7 μm (more specifically, 0.50 to 0.62 μm) Compared with the light diffusers of Examples 1-10, the total light transmittance was low and the light transmittance was inferior.

In addition, regarding the light-diffusing body of Comparative Example 4 formed from a light-diffusing resin composition in which the content of barium sulfate is 0.25 parts by weight with respect to 1 part by weight of resin particles, the content of barium sulfate is 0.25 parts by weight with respect to 1 part by weight of resin particles. Compared with the light diffusers of Examples 1 to 10, in which the particles are 0.5 to 1.35 parts by weight (more specifically, 0.6 to 1.33 parts by weight) of the light diffusing resin composition, the degree of dispersion is low and the light diffusibility is poor.

In addition, regarding the comparative example 5 formed from the light-diffusing resin composition in which the content of resin particles is 1 part by weight with respect to 100 parts by weight of base resin, and the content of barium sulfate is 4 parts by weight with respect to 1 part by weight of resin particles. The light diffuser, the content of the resin particles is 1.5 to 2.5 parts by weight relative to 100 parts by weight of the base resin, and the content of barium sulfate is 0.5 to 1.35 parts by weight relative to 1 part by weight of the resin particles (more specifically, 0.6 to 1.33 parts by weight) of the light-diffusing resin composition, the total light transmittance was low and the light transmittance was poor compared to the light-diffusing bodies of Examples 1-10.

In addition, the light-diffusing bodies of Comparative Examples 6 to 8 formed from the light-diffusing resin composition not containing barium sulfate were compared with the light-diffusing bodies of Examples 1-10 formed from the light-diffusing resin composition containing barium sulfate , with low dispersion and poor light diffusion. Moreover, the color difference after the accelerated exposure of the light diffusers of Comparative Examples 7 and 8 exceeded 3, and was inferior to light resistance.

In addition, implementation of the production of the light diffuser of Comparative Example 9 using barium sulfate having a volume average particle diameter of 0.75 μm and using barium sulfate having a volume average particle diameter of 0.4 to 0.7 μm (more specifically, 0.50 to 0.62 μm) Compared with the light diffusers of Examples 1 to 10, the degree of dispersion was low and the light diffusivity was inferior.

The light diffuser of Comparative Example 10 manufactured using resin particles (D) with a refractive index of 1.496 and the light diffuser manufactured using any of resin particles (A), (B) and (E) to (H) with a refractive index of 1.540 to 1.560 Compared with the light diffusers of Examples 1 to 10, the dispersion degree was low and the light diffusivity was inferior.

Claims (8)

1. A light diffuser, characterized in that it is formed from a light diffusing resin composition in which resin particles and an inorganic compound are dispersed in a base resin, The resin particles are polymer particles comprising a monomer mixture of (meth)acrylic monofunctional monomers and polyfunctional monomers, with a volume average particle diameter of 2-10 μm and a refractive index of 1.540-1.560, The inorganic compound is barium sulfate with a volume average particle diameter of 0.4-0.7 μm, The light-diffusing resin composition contains 1.5 to 2.5 parts by weight of the resin particles with respect to 100 parts by weight of the base resin, The content ratio of the said resin particle and the said inorganic compound in the said light diffusing resin composition exists in the range of 1:0.5-1:1.35 by weight ratio. 2 . The light diffuser according to claim 1 , wherein the multifunctional monomer is a (meth)acrylate multifunctional monomer. 3. The light diffuser according to claim 1, wherein the monomer mixture comprises styrenic monofunctional monomers. 4. The light diffuser according to claim 2, wherein the monomer mixture comprises styrenic monofunctional monomers. 5 . The light diffuser according to claim 1 , wherein the base resin is an acrylic resin. 6. The light diffuser according to any one of claims 1 to 4, wherein the light diffusing resin composition contains a rubber component, and the rubber component is 100 parts by weight of the base resin. The content of the components is 1 to 10 parts by weight. 7. The light diffuser according to any one of claims 1 to 4, wherein the thickness of the light diffuser is 1.0 to 3.0 mm. 8. The light diffusing body according to any one of claims 1 to 4, wherein the light diffusing resin composition is formed by extrusion molding, and the light diffusing resin composition The resin composition is obtained by mixing the resin particles, the inorganic compound, and the base resin.