JP2000239407A - Resin sheet for lighting cover excellent in light diffusivity and color tone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the light transmittance and light diffusivity without impairing the various color tones inherent in a light source by uniformly dispersing rutile titanium dioxide and a specified particulate light diffusing agent in a transparent resin. SOLUTION: Rutile titanium dioxide with a particle diameter of 0.01-0.1 μm, in an amount of 0.005-0.1 pt.wt., and at least one particulate light diffusing agent selected from a silicone, barium sulfate, calcium carbonate and a crosslinked transparent resin and having a weight-mean particle diameter of 0.1-50 μm, in an amount of 0.1-10 pts.wt. are dispersed in 100 pts.wt. transparent resin comprising a methacrylic resin or an MS resin and having a haze value (JIS K 7105) of 10% or lower. A sheet is formed from the dispersion to give a resin sheet for a lighting cover satisfying the relations of the formulas: 40<X<70, Y<=-0.66X+121, Y>=0.49X+89, |XL+XT|<=0.015, and |YL+YT|<=0.035. In the formulas, X is total light transmittance; Y is light diffusivity; XL and YL are chromaticity coordinates of a standard light source prescribed by JIS Z 8720; and XT and YT are chromaticity coordinates of a light reflected by the resin sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting cover member and a lighting cover formed from the same, and more particularly, to a lighting cover member which satisfies a balance between light transmittance and light diffusion, and which emits light when it is turned on in a light source of various colors. The present invention relates to a resin sheet for a lighting cover which does not impair the color tone of a light source and is preferably white when turned off and has no strong presence, and a lighting cover formed from the resin sheet.

[0002]

2. Description of the Related Art As an example of a light source protective cover that sufficiently transmits light from a light source and uniformly diffuses the light source to prevent the light source from directly contacting an observer's eyes, a home and facility lighting cover is used. , Various displays, display signs, and the like. Conventionally, these members have been required to have a function of being able to be formed into an arbitrary shape and to have a function of transmitting and diffusing the light amount of a light source, and to disperse fine particles having different refractive indexes in a transparent resin. Investigations have been made on transmission high diffusivity materials.

[0003] For example, a resin composition in which an inorganic powder such as glass is dispersed in a methacrylic resin (JP-A-54-1552).
No. 44) and a resin plate containing a transparent resin containing a solid silicone resin having a specific structure and a particle size and forming a polysiloxane bond (Japanese Patent Application Laid-Open No. 1-172801). Further, a resin plate for lighting which adjusts light transmittance and light diffusivity by regulating the light diffusing agent and the dye / pigment concentration in the transparent resin (JP-A-6-111612), and white fluorescent light having a prescribed transmission color tone Light diffuser plate for lamp cover
306217).

Further, a color tone sheet for a light source protective cover previously proposed by the present inventors (Japanese Patent Application Laid-Open No. Hei 9-14989).
Is a resin sheet which does not impair the color tone of various original light sources and is excellent in light transmittance and light diffusion.

[0005]

The light-diffusing resin member disclosed in these prior arts maximizes the light of the light source as a light source protection cover, and provides uniform brightness without the image of the light source being transparent. The main focus is on obtaining a surface with a good surface, or on the color tone as a light source protective cover material. That is,
The aforementioned Japanese Patent Application Laid-Open No. 54-155244,
In 72801, the color tone of the material is so-called milky white, but when used as a light source cover, the original color tone of the light source changes when the light source is turned on. There is a problem that the color tone is deteriorated at the time of turning on and off, which is not preferable in appearance.

[0006] In recent years, the use of low-power, high-brightness type light sources has been increasing in effective use of energy, but attention has also been paid to means for creating a comfortable space at the same time.
It is positioned as a product that enriches the living environment, such as harmony with indoor interiors, directing in gallery facilities and stores, and improving the scenery by lighting up buildings. In particular, there is a great need for illumination having high color rendering properties, and a variety of light sources having various color tones have been proposed, and a light source protective cover material that does not impair the color tone of these light sources is required.

In the above-mentioned Japanese Patent Application Laid-Open No. 6-111612, light transmission and light diffusion are individually described. In Japanese Patent Application Laid-Open No. 9-306217, transmission color is individually shown. Satisfies the balance, and does not impair the color tone of the original light source when the light source of various colors is turned on.
There is no disclosure of a lighting cover member that satisfies any of the conditions, which does not have a strong presence, and a lighting cover formed from the same.

Japanese Patent Application Laid-Open No. 9-14989 discloses a resin sheet which does not impair the color tone of various original light sources and is excellent in light transmittance and light diffusion property. Met. The present invention relates to a resin sheet having excellent optical properties, and a molded article of an illumination cover formed from the resin sheet. More specifically, the present invention satisfies the balance between light transmission and light diffusion, and is suitable for light sources of various colors. An object of the present invention is to provide a lighting cover which does not impair the color tone of a light source and has excellent light transmittance and light diffusion.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a resin sheet in which a specific pigment and a diffusing agent are used in combination with a transparent resin and these are uniformly dispersed. And the total light transmittance and light diffusivity, and JIS-
There is a specific relationship between the chromaticity coordinates of the transmitted light measured using the two types of standard light sources (A, C) specified in Z8720,
Further, only when the relationship is satisfied, an excellent lighting cover sheet is obtained which satisfies the balance between light transmittance and light diffusion and does not impair the color tone of the original light source in light sources of various colors. The present invention has been found.

That is, in the present invention, the rutile crystal type titanium oxide and the particulate light diffusing agent are uniformly dispersed in the transparent resin,
The particulate light diffusing agent is at least one selected from silicone, barium sulfate, calcium carbonate, and a cross-linked transparent resin. In the relationship between the total light transmittance and the light diffusivity, the total light transmittance is X, and the light diffusivity is Is Y, X and Y are in the ranges of the following formulas (1) to (3), respectively: 40 <X <70 (1) Y ≦ −0.66X + 121 (2) Y ≧ −0.49X + 89 (3 When a chromaticity coordinate of transmitted light is measured using a standard light source specified in JIS-Z8720, a resin for an illumination cover in which all measured values at each light source simultaneously satisfy the following expressions (4) and (5). It is a sheet.

| X _L −x _T | ≦ 0.015 (4) | y _L −y _T | ≦ 0.02 (5) (where x _L and y _L are chromaticity coordinates of a standard light source, x _T , y _T
Represents chromaticity coordinates of light transmitted through the resin sheet. In the above invention, at least one kind and amount of at least one selected from the group consisting of rutile crystalline titanium oxide as a pigment and silicone, barium sulfate, calcium carbonate, and a cross-linked transparent resin as a particulate light diffusing agent are appropriately determined. , JIS-Z872
When the chromaticity coordinates of the reflected light are measured using the standard light source specified by 0, it is more preferable that all the measured values of each light source satisfy the following expressions (6) and (7) simultaneously.

| X _L −x _R | ≦ 0.03 (6) | y _L −y _R | ≦ 0.035 (7) (where x _L and y _L are chromaticity coordinates of a standard light source, x _R , y _R
Represents the chromaticity coordinates of the reflected light of the resin sheet. In the present invention, the transparent resin is preferably a methacrylic resin or an MS resin, and the rutile crystalline titanium oxide of the pigment has an average particle diameter of 0.1 to 1 μm, and the surface thereof is an aluminum compound. It is coated with at least one selected from the following group of zinc compounds and silicon compounds, and has an average particle diameter of 0.1 as a particulate light diffusing agent.
It is preferably applied that at least one selected from silicone, barium sulfate, calcium carbonate, and a cross-linked transparent resin of 1 to 50 μm is uniformly dispersed and contained. Further, the present invention, the above-mentioned resin sheet, square, round,
It is preferably applied to a lighting cover formed in a dome shape or the like.

The transparent resin used in the present invention is defined by JIS
It is defined as a substance having a haze of 10% or less as measured according to K-7105. Specific examples include methacrylic resin, MS resin, polycarbonate resin, and polystyrene resin. Particularly preferred are methacrylic resins and MS resins. The methacrylic resin that can be used in the present invention includes a resin mainly composed of methyl methacrylate, which includes a homopolymer of methyl methacrylate, or methyl methacrylate and methyl acrylate,
Examples include copolymers with any one or more copolymerizable monomers such as ethyl acrylate, butyl acrylate, acrylonitrile, acrylic acid, methacrylic acid, 2-hydroxyacrylate, maleic anhydride, and α-methylstyrene. These may be used alone or may be blended. In order to maintain transparency and simultaneously provide impact resistance, an impact-resistant methacrylic resin blended with a methacrylic rubber elastic material is used, and the methacrylic rubber elastic material is disclosed in JP-A-53-58554. Id. 55-9
No. 4,917, 61-32346, and the like. Briefly, it is a multi-stage polymer produced by a multi-stage sequential polymerization method in which an elastic layer and an inelastic layer are alternately formed around a methacrylic polymer core material.

The MS resin that can be used in the present invention is a resin mainly composed of a copolymer of methyl methacrylate and styrene, and one or more copolymerizable monomers as exemplified in the above methacrylic resin are added. And multicomponent copolymers. When the total amount of the MS resin is 100 parts, a resin having a methyl methacrylate ratio of more than 60 parts has good light resistance and is more preferable.

Titanium oxide is generally used as a pigment for coloring white in various paints and plastics because of its excellent whiteness and hiding properties. Among them, rutile crystal type titanium oxide has high light resistance and has been used in fields requiring durability such as lighting applications. When used as a coloring pigment, its dispersibility becomes a major problem.If the dispersion of the pigment particles is insufficient, or if the particles are agglomerated, not only the inherent coloring function cannot be sufficiently exhibited, but also the gloss of the product surface can be reduced. It is not preferable because it is bad, and if it is remarkable, a bump-like defect is generated on the product surface.

When the titanium oxide particle size is in the range of 0.01 to 0.1 μm, the above-mentioned bumpy surface defect phenomenon is hardly observed, but the titanium oxide particle size is in the range of 0.1 to 1 μm. In the case of titanium, it is preferable to coat the surface with an appropriate substance to increase dispersibility. The titanium oxide used in the present invention is rutile crystalline titanium oxide (TiO ₂ ), the surface of which is coated with an aluminum compound and at least one selected from the group consisting of a zinc compound and a silicon compound.
Those having 90% or more as the _two components are most preferable because they have excellent light resistance, whiteness, and dispersibility.

The silicone which is the particulate light diffusing agent of the present invention may be a polyorganosilsesquioxane resin generally called a silicone resin, or a silicone cured silicone having a linear organopolysiloxane block generally called a silicone rubber and having rubber elasticity. A product, a product obtained by coating the surface of the silicone rubber particles with the silicone resin, and a mixture thereof are shown.

Barium sulfate and calcium carbonate are general-purpose inorganic light diffusing agents, and cross-linking transparent resins such as acrylic resin, MS and styrene are also well known as light diffusing agents. A mixture of a diffusing agent may be used. When the weight average particle diameter of the light diffusing fine particles used in combination is in the range of 0.1 to 50 μm, refraction and reflection of visible light at the interface of each particle effectively occur in the transparent resin, and light transmission and light diffusion are performed. It is preferable in that a sheet for a light source protective cover having excellent properties can be obtained.

The particle size distribution of the rutile crystalline titanium oxide and the particulate light diffusing agent used in the present invention is measured by a known light transmission type sedimentation particle size distribution measuring method, and the weight average particle size is determined from the obtained distribution. You can ask. If the weight average particle size does not fall within the desired range, the particles can be classified and used within the above range. Examples of the particulate light diffusing agent used in the present invention include calcium fluoride,
Potassium fluoride, magnesium sulfate, aluminum hydroxide, magnesium hydroxide, crystalline silica, amorphous silica, glass flake, glass fiber, alumina, mica,
Examples include inorganic substance particles such as talc and clay, and these may be used in combination.

The rutile crystal type titanium oxide particles used in the present invention have a content of 0.005 to 100 parts by weight of the transparent resin.
0.1 parts by weight, the particulate light diffusing agent has a total content of at least one kind of particulate light diffusing agent of 0.1 to 10 parts by weight, more preferably 0.5 to 100 parts by weight of the transparent resin. -5 parts by weight. In this range, the color tone can be adjusted without extremely lowering the optical characteristics when dispersed in the transparent resin, particularly the total light transmittance, and a preferable resin sheet for an illumination cover can be obtained.

In the present invention, when a known fluorescent whitening agent is contained in the transparent resin, the color tone is further stabilized by the combined effect with the white fine particles, and the original color tone is exhibited by various light sources. Recommended by the point. The content of the fluorescent whitening agent is
It is preferably in the range of 0.001 to 0.1 part by weight based on 100 parts by weight of the transparent resin. Further, a known bluing agent is added in an amount of 0.00000 to 100 parts by weight of the transparent resin.
It is possible to arbitrarily adjust the color tone by adding 5 to 0.0002 parts by weight.

The structure of the light source protective cover sheet according to the present invention may be a single-layer structure comprising a transparent resin, the above-mentioned rutile crystal type titanium oxide, and a particulate light diffusing agent. As (A), a multilayer structure having a surface layer (B) made of a transparent resin on one or both surfaces thereof is also preferably applied. The surface layer (B) made of a transparent resin allows the color tone of the sheet to be finely adjusted, and the surface layer (B)
Antistatic properties, surface matting properties, surface gloss, solvent resistance,
Providing a function such as anti-fogging property is preferable in that the function can be enhanced without significantly changing the original physical performance of the sheet.

As the transparent resin of the surface layer, a methacrylic resin or an MS resin is preferably used because it is excellent in surface texture and luxury when used for a light source protective cover and excellent in workability. The base material layer (A) and the surface layer (B)
When the thickness of the entire sheet is set to 1, the thickness of the base material layer (A) is preferably 0.5 or more.
More preferably, it is 7 or more. If the ratio of the thickness of the base material layer to the total sheet thickness is within this range, the characteristics of the sheet for the light source protection cover are determined by the color tone and optical characteristics of the base material layer, and a wide variety of light source protection covers can be used regardless of the layer structure. The design of the seat is possible.

The thickness of the light source protective cover sheet is 0.1 to
The range of 5 mm is preferable, and if it is less than 0.1 mm, the strength of the sheet is low, and if it exceeds 5 mm, the weight becomes large and mounting becomes difficult. The method for producing the light source protective cover sheet in the present invention is preferably a method in which rutile crystal type titanium oxide and a particulate light diffusing agent are uniformly dispersed in a transparent resin, for example, a polymerizable monomer or partially polymerized polymer. The polymer can be obtained by dispersing the particles in a syrup of a hydrophilic monomer and polymerizing the particles, or by mixing, melt-kneading and extruding the particles in a transparent resin that has been polymerized in advance, or the like.

In order to obtain a smooth, corrugated, prism-shaped sheet or the like, a typical example is an extrusion sheet molding method using a T-die. The sheet can be subjected to secondary processing by a method such as vacuum forming or air pressure forming, and can be used as a light source protective cover. Further, the sheet for the light source protective cover can be obtained by a method such as a profile extrusion molding using a profile die, a blow molding, an injection molding, and a compression molding.

In order to obtain a sheet having a multilayer structure, a coextrusion molding method in which two or more resin compositions are simultaneously melted and extruded,
A method of laminating one of the two types of resin compositions while extruding one of them in a single layer, a method of pressing and thermocompression bonding after preforming the two types of resin compositions, a method of continuously overlapping and bonding , Vacuum forming, laminating at the time of pressure forming, and the like.

The light source protective cover sheet according to the present invention contains other components such as a filler, a matting agent, a releasing agent, a heat stabilizer, and the like, as long as the color tone, optical characteristics, and other physical properties are not impaired. Additives such as an antioxidant, a light stabilizer, an ultraviolet absorber, and a plasticizer can be contained in an optional process at the time of manufacturing a sheet raw material or at the time of forming a sheet.

In the present invention, the total light transmittance is JIS-
The light diffusivity is measured according to the DIN-5036 method according to the K7105 method.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to examples and comparative examples. The evaluation and test methods used in each example and comparative example are as follows. The amounts are all parts by weight. (1) Evaluation of total light transmittance: Measured using a 1001-DP haze meter manufactured by Nippon Denshoku Industries Co., Ltd. according to JIS-K7105 method. (2) Evaluation of light diffusivity: In accordance with the DIN-5036 method, the suitability of the illumination cover is evaluated in detail by measuring the diffused light amount of a light source in a wide range. That is, using a goniometer photometer manufactured by Optec Co., Ltd., the emission angles are 5 °, 20 °, and 7 ° under the conditions of a parallel light beam diameter of 30 mmφ and a light receiving unit light beam diameter of 10 mmφ.
Each diffused light amount at 0 degree is measured, and the light diffusivity is calculated by the following equation. Light diffusivity (%) = {(20 degree diffused light quantity + 70 degree diffused light quantity) / 5 degree diffused light quantity × 2} × 100 (3) Measurement of chromaticity coordinates: TEPCO according to JIS-Z8722 method Using a color industry TC-1800 type automatic color analyzer, the chromaticity coordinates x _L and y _{L of} the standard light source, the chromaticity coordinates x _T of the transmitted light of the sheet test piece,
y _T and the chromaticity coordinates x _R and y _R of the reflected light are measured. The evaluation is performed using two types of standard light sources, A light source and C light source. For ease express the evaluation result, the absolute value of the difference between each chromaticity coordinate _{Δx T = | x L -x T} | Δy T = | y L -y T | Δx R = | x L -x R | [Delta] y _R = | shown as | y _L -y _R. (4) Fluorescent lamp mounting evaluation: A sheet test piece was mounted on two types of fluorescent lamps for general illumination (bulb color (L) and neutral white (N)) specified in JIS-C7601, and the lamp was turned on and off. The color tone at the time of lighting and the intensity of the image through which the outline of the fluorescent lamp is seen through are visually evaluated. In the evaluation results, the circles represent the state in which the color tone of the fluorescent lamp is not impaired in both lighting and extinguishing, and the state in which the outline of the lamp is not so visible and the image is relatively weak.

The crosses indicate a state in which the color tone of the fluorescent lamp changes when the lamp is turned on or off, and a state in which the outline of the lamp is seen through and the image is relatively strong. If all the two types of lamps can be used without any problem, the judgment is ◎. If there is a problem in use even in one state, the judgment is ×. (5) Measurement of Particle Size Distribution of Rutile Crystalline Titanium Oxide and Light-Diffusing Fine Particles: The particles are dispersed in an aqueous surfactant solution by ultrasonic waves, and a centrifugal automatic particle size distribution analyzer (CAPA-700 manufactured by Horiba, Ltd.) ), And the particle size distribution is measured by a light transmission type sedimentation particle size distribution measuring method. From the obtained particle size distribution, a weight average particle size _Dd is determined.

Table 1 shows the adjustment of the sheet material for the light source protective cover.
As shown in, a methacrylic resin (trade name: Del Powder 70H, manufactured by Asahi Kasei Kogyo Co., Ltd.), a particulate rutile crystal type titanium oxide, a particulate light diffusing agent, and other components are blended as a transparent resin, and a tumbler is added. After mixing uniformly using a vented extruder 30 mmφ twin screw extruder, resin temperature 25
Melt kneading at 0 ° C. to form pellets, sheet materials A1 to A
Get 6.

Similarly, as shown in Table 2, methacrylic resin (trade name: Del Powder 70H, Asahi Kasei Corporation)
) And other components are mixed, homogeneously mixed using a tumbler, melt-kneaded at a resin temperature of 250 ° C. with a vented extruder 30 mmφ twin-screw extruder, and pelletized to obtain a raw material B1.
Get. The titanium oxide used in Table 1 was manufactured by Fuji Titanium Industry Co., Ltd., and TR840 had an average particle size of 0.37 μm, and was made of aluminum oxide (Al ₂ O ₃ ), zinc oxide (ZnO), and silicon oxide (SiO ₂ ). Surface coated 9 TiO ₂
4%, TR900 has an average particle size of 0.34 μm, and is surface-coated with aluminum oxide (Al ₂ O ₃ ) and zinc oxide (ZnO) and has a TiO ₂ component of 95%. Both are rutile-type titanium oxides. As the particulate light diffusing agent, the silicone resin-1 is Tospearl 2000B (trade name, manufactured by Toshiba Silicone Co., Ltd.) and has an average particle size of 6 μm.

Char-Cal-1 is a heavy calcium carbonate and has an average particle size of 2 μm under the trade name ACE35 manufactured by Dowa Mining Co., Ltd. Char-Cal-2 is also a heavy calcium carbonate and its trade name AC
It has an average particle size of 1.5 μm according to E25. Barium sulfate is AD sedimentable barium sulfate manufactured by Nippon Chemical Industry Co., Ltd. and has an average particle size of 3 μm.

The other component, bluing agent-1, was Diaresin Blue N manufactured by Mitsubishi Chemical Corporation, and bluing agent-
2 is Macrolex Violet B manufactured by Bayer Corporation
And a whitening agent is White Flow HCS (trade name, a fluorescent whitening agent manufactured by Sumitomo Chemical Co., Ltd.). In the other components in Table 2, talc powder is NTX-A174 (trade name, manufactured by Nippon Talc Co., Ltd.).
The silicone resin-2 was manufactured by Toshiba Silicone Co., Ltd. under the trade name Tospearl 120 (average particle size: 2 μm).
Sumitomo Chemical Co., Ltd. Optical Brightener Brand Name White Flow H
Indicates CS.

[0035]

Example 1 Using a sheet material A1 shown in Table 1, an extruder (screw diameter 50 mmφ, L / D = 32, single axis), a sheet die, and a sheet forming machine having three polishing rolls were used to form a sheet having a width of 280 mm. Create a sheet. The thickness of the sheet is set to 2 mm by adjusting the extrusion amount of the extruder, the sheet take-up speed, and the clearance of the polishing roll. The obtained sheet is a good sheet having a glossy surface and no defects such as bumps on the surface.

[0036]

Example 2 A sheet is prepared in the same manner as in Example 1 except that A2 is used as a sheet material.

[0037]

Example 3 The extruder of the sheet forming unit used in Example 1 was the first extruder, to which the second extruder (screw diameter 25 mmφ, L / D = 32, single screw) and the feed block were connected. Then, a two-type three-layer sheet is formed by a co-extrusion method. The first extruder uses sheet material A3 as a base material layer, and the second extruder uses sheet material B1 as a surface layer. The obtained sheet has a configuration in which a surface layer is laminated on both sides of a base material layer, and the thickness of each layer is adjusted by the balance between the extrusion amounts of the first and second extruders. Thus, a sheet having a surface layer of 30 μm each and an overall thickness of 2 mm is obtained.

[0038]

Comparative Examples 1 to 3 A4 (Comparative Example 1) as a sheet material,
A sheet is prepared in the same manner as in Example 1 except that A5 (Comparative Example 2) and A6 (Comparative Example 3) are used.

[0039]

[Comparative Example 4] Of the raw materials used in Example 1, titanium oxide having the same average particle size but having no surface coating was replaced with a sheet, and a lip portion of a sheet die was formed at the time of extrusion. Foreign matter was deposited, and a linear defect caused by the foreign matter occurred on the sheet surface. In addition, a bump-like defect is observed on the surface of the obtained sheet, which impairs the quality.

Tables 3 to 5 collectively show the evaluation results of the sheets obtained in Examples 1 to 3 and Comparative Examples 1 to 3 in terms of light transmittance and diffusion, color tone, and mounting of a fluorescent lamp. The sheets of Examples 1 to 3 all fall within the range specified in the present invention, and the balance between the optical characteristics and the color tone is extremely excellent. That is, as shown in Table 3, the total light transmittance is 40
% And less than 70%, and the light diffusivity was determined from the numerical value (expressed as YH in Table 3) and the expression -0.49X + 89, where X is the total light transmittance of each. numerical located in (denoted in Table 3 YL) range, and the chromaticity difference between the transmitted light of a standard light source and the test piece as shown in Table 4 even in in any of the light _{source, Δx T ≦ 0.015, Δy T} ≦
It is preferably in the range of 0.02.

Further, in the third embodiment, the chromaticity difference of the reflected light is also Δx _T ≦ 0.03 and Δy _T ≦
It is in the range of 0.035 and is very preferred. Table 5
As shown in (2), the use of any of the two fluorescent lamps does not impair the color tone and can be used for each lamp without any problem. The lamp image is weak and good, and the judgment is ◎.

In Example 3, since talc, which is a matting agent, was added to the surface layer during coextrusion, the sheet surface exhibited a matte mat state, and had a texture with little reflection due to surface reflection of external light. It is an excellent light diffusion sheet for lighting. In Comparative Example 1, the total light transmittance and the light diffusivity fall within the ranges specified in the present disclosure, but the chromaticity difference Δy _T between the standard light source and the test piece in the C light source is ≦ 0. 02, which is not preferable. Further, in the reflected light, Δy _{R of} the C light source is not preferable because it does not fall within the range specified in the present invention.

When the lamp is mounted on an N-color fluorescent lamp, its color tone is impaired. Comparative Example 2 is not preferable because the light diffusion rate is not within the range specified in the present invention and the lamp image is strong. In Comparative Example 3, as in Comparative Example 2, the light diffusivity is not in the range, the lamp image is strong, and Δx _T is not in the range in the transmitted light from the C light source, which is not preferable.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

[Table 3]

[0047]

[Table 4]

[0048]

[Table 5]

[0049]

The resin sheet for a lighting cover obtained by the present invention, and the one obtained by molding it into a lighting cover, can effectively transmit and diffuse the light emitted from the light source, and can be used when lighting with various light sources. This is extremely useful because it can be used in common for various light sources without deteriorating its color tone when turned off.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 83/04 C08L 83/04 101/12 101/12

Claims (4)

[Claims] 1. A transparent resin in which rutile crystalline titanium oxide and a particulate light diffusing agent are uniformly dispersed, and the particulate light diffusing agent is selected from silicone, barium sulfate, calcium carbonate, and a cross-linked transparent resin. At least one kind,
In the relationship between the total light transmittance and the light diffusivity, when the total light transmittance is X and the light diffusivity is Y, each of X and Y is in the range of the following formula, and 40 <X <70 (1) Y ≦ −0.66X + 121 (2) Y ≧ −0.49X + 89 (3) When the chromaticity coordinates of the transmitted light are measured using the standard light source specified in JIS-Z8720, all the measured values at each light source are as follows. A resin sheet for a lighting cover, wherein the resin sheet satisfies the expressions (4) and (5) at the same time. | X _L −x _T | ≦ 0.015 (4) | y _L −y _T | ≦ 0.02 (5) (where x _L and y _L are the chromaticity coordinates of the standard light source, x _T and y _T
Represents chromaticity coordinates of light transmitted through the resin sheet. ) 2. The resin sheet according to claim 1, wherein
Furthermore, when the chromaticity coordinates of the reflected light are measured using a standard light source defined by JIS-Z8720, all the measured values at each light source satisfy the following expressions (6) and (7) simultaneously. Lighting resin sheet. | X _L −x _R | ≦ 0.03 (6) | y _L −y _R | ≦ 0.035 (7) (where x _L and y _L are the chromaticity coordinates of the standard light source, x _R and y _R
Represents the chromaticity coordinates of the reflected light of the resin sheet. ) 3. The transparent resin is a methacrylic resin or MS.
It is a resin and has an average particle size of rutile crystal type titanium oxide of 0.1.
1 to 1 μm, and the surface of which is selected from the group consisting of an aluminum compound, a zinc compound of the next group, and a silicon compound.
Seeds, the particle size of the particulate light diffusing agent is 0.1 to 50 μm, and silicone, barium sulfate,
The resin sheet for a lighting cover according to claim 1, wherein the resin sheet is at least one selected from calcium carbonate and a cross-linked transparent resin. 4. An illumination cover molded article obtained by molding the resin sheet according to claim 1.