JP2009103916A - Light reflection board and lighting body using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light reflection board which has excellent light reflexivity and is excellent in manufacturing efficiency. <P>SOLUTION: In the light reflection board A, a plurality of concave parts 2, which are made by swelling a thermoplastic resin sheet 1 with light reflexivity from its surface to its rear surface by thermal formation, are formed in vertical and horizontal succession. An inner bottom surface of the concave part 2 is formed to a light source disposition part 23 for disposing a light source and further an inner peripheral surface of the concave part 2 is formed to a light reflection surface 22c for reflecting light emitted from the light source. The concave part 2 is thermally formed to an optimal shape according to the kind of the light source and can effectively reflect the light emitted from the light source. Thus the light reflection board has excellent light reflexivity. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light reflector having excellent light reflectivity and an illuminating body using the same.

  Conventionally, a thermoplastic resin sheet is processed into a three-dimensional shape to form a light reflecting plate, and a light source such as a light emitting diode is disposed on the light reflecting plate, which is used as a lighting device. As such a light reflecting plate, in Patent Document 1, a light reflecting plate processed into a three-dimensional shape by forming a cut in a predetermined portion of a plastic film or sheet that reflects light and bending the cut along the cut. Is disclosed.

  However, since the light reflecting plate is formed with a notch in the thermoplastic resin sheet and bent along the notch, a gap due to the notch is generated on the light reflecting surface of the light reflecting plate. The light incident on the surface is not reflected in the gaps on the light reflecting surface, the light reflectivity is lowered, and the light reflected from the light reflecting plate is not uniform. Further, a process for forming a cut in the thermoplastic resin sheet is required, and the production efficiency is inferior.

  Further, Patent Document 2 discloses a light reflecting plate having an electrically insulating base material having a through hole for accommodating a light emitting element, the through hole having a first opening and one turn more than the first opening. The second opening has a plating film formed on the surface of the first opening, while the second opening exposes the electrically insulating substrate to prevent a short circuit with the wiring of the light emitting element. A light reflecting plate is disclosed.

  However, although the light emitted from the light emitting element is reflected by the plating film, the light reflection by the plating film is low in efficiency, and the plating film is not formed in the second opening of the through hole. Since the light emitted from the element cannot be reflected, the light reflectivity is insufficient.

WO2005 / 066664 JP 2006-80003 A

  The present invention provides a light reflector having excellent light reflectivity and excellent production efficiency, and an illuminating body using the light reflector.

  The light reflecting plate of the present invention has a plurality of recesses formed by thermoforming a light-reflecting thermoplastic resin sheet from the front surface to the back surface, and is formed continuously in the vertical and horizontal directions. The inner bottom surface is formed in a light source disposition portion for disposing a light source, and the inner peripheral surface of the recess is formed as a light reflecting surface that reflects light emitted from the light source. To do.

  And in the said light reflection plate, the recessed part is formed in reverse truncated cone shape, It is characterized by the above-mentioned. Further, the light reflecting plate is characterized in that the concave portion has a reverse truncated quadrangular pyramid shape.

  Further, in the light reflecting plate, the opening edges of the recesses adjacent to each other are connected via a connecting portion, and the bent portion of the light reflecting surface of the recess and the surface of the connecting portion are formed in a curved surface. It is characterized by that.

  In the light reflecting plate, the thermoplastic resin sheet is composed of 100 parts by weight of thermoplastic resin, 10 to 100 parts by weight of titanium oxide, 0.01 to 0.8 part by weight of primary antioxidant, 0.2% by weight of secondary antioxidant. It contains 01 to 0.8 part by weight, an ultraviolet absorber 0.01 to 0.8 part by weight, and a hindered amine light stabilizer 0.01 to 0.8 part by weight.

  In the above light reflecting plate, the thermoplastic resin is a polyolefin resin, the primary antioxidant is a phenolic antioxidant, and the secondary antioxidant is a phosphorus antioxidant. .

  Furthermore, the illuminating body is characterized in that a light emitting diode is disposed in a light source disposition portion of the light reflecting plate.

  The light reflecting plate of the present invention has a plurality of recesses formed by thermoforming a light-reflecting thermoplastic resin sheet from the front surface to the back surface, and is formed continuously in the vertical and horizontal directions. The inner bottom surface is formed in a light source disposition portion for disposing a light source, and the inner peripheral surface of the recess is formed as a light reflecting surface that reflects light emitted from the light source. The recess is thermoformed into an optimal shape according to the type of light source, and can effectively reflect the light emitted from the light source and has excellent light reflectivity.

  Furthermore, since the concave portion is bulged and formed by thermoforming the thermoplastic resin sheet, the light reflecting surface of the concave portion has no cuts or cracks and is formed on a smooth surface. The emitted light can be reliably reflected on the light reflecting surface without leaking outside.

  And when the said recessed part is formed in the shape of a reverse truncated cone, it can reflect effectively outwards, disperse | distributing light with the light reflection surface of a recessed part, and the more excellent light reflection Have sex. The truncated cone shape refers to a shape obtained by excising the top of the weight.

  Further, in the case where the concave portion has a reverse truncated quadrangular pyramid shape, the concave portion can be formed continuously in the vertical and horizontal directions with substantially no gap, and the width of the connecting portion that connects the opening ends of the adjacent concave portions. Can be made as narrow as possible, and the area occupied by the light reflecting surface with respect to the entire area of the concave-formed surface of the light reflecting plate can be increased to improve the light reflectivity.

  Moreover, when the opening edge of the recessed part adjacent to each other is connected through the connection part and the bent part of the light reflection surface of the said recessed part and the surface of the said connection part are formed in the curved surface, light reflection is carried out. Light incident from the outside of the plate can be reflected efficiently and uniformly at the connecting portion, and light emitted from the light source can be reflected more efficiently at the light reflecting surface of the recess.

  And a thermoplastic resin sheet | seat is 100 weight part of thermoplastic resins, 10-100 weight part of titanium oxide, 0.01-0.8 weight part of primary antioxidant, 0.01-0.8 weight of secondary antioxidant. Parts, UV absorber 0.01 to 0.8 parts by weight and hindered amine light stabilizer 0.01 to 0.8 parts by weight, depending on the primary antioxidant and secondary antioxidant, In addition to preventing yellowing due to deterioration of the thermoplastic resin, it also prevents decomposition of the UV absorber and hindered amine light stabilizer by titanium oxide, and the protected UV absorber and hindered amine. The light stabilizer of the present invention is intended to prevent the oxidative decomposition of organic substances by titanium oxide and to suppress the photochemical change of titanium oxide. Therefore, the light reflector of the present invention has a short light reflectivity at the beginning. With never lowered greatly among, maintaining excellent light reflectivity even for a long period of time.

  And since the thermoplastic resin sheet contains titanium oxide which is an inorganic filler, the titanium oxide in the thermoplastic resin sheet is also heated by the heating at the time of the thermoforming of the thermoplastic resin sheet. Since the thermoplastic resin sheet is also heated from the inside, the thermoformability of the thermoplastic resin sheet is improved, the concave portions can be bulged and formed more accurately by thermoforming, and the light reflector is more excellent It has light reflectivity.

  An example of the light reflecting plate of the present invention will be described with reference to the drawings. The light reflecting plate A is formed by thermoforming a thermoplastic resin sheet 1 having light reflectivity. As shown in FIGS. 1 and 2, the light reflection plate A swells by thermoforming the flat rectangular thermoplastic resin sheet 1 from the front surface to the back surface at a portion excluding the outer periphery of the four sides. ... so that a large number of inverted truncated quadrangular pyramid-shaped recesses 2, 2, ... have their opening edges parallel to the long or short sides of the thermoplastic resin sheet 1. It is formed continuously in the vertical and horizontal directions.

  Specifically, the concave portion 2 is composed of a bottom surface portion 21 having a planar square shape and a peripheral wall portion 22 extending in a state of gradually expanding from the four-side outer periphery of the bottom surface portion 21 toward the surface side. In this peripheral wall portion 22, four inverted isosceles trapezoidal peripheral wall pieces 22a, 22a,... Share the opposite inclined sides over the entire length between the adjacent peripheral wall piece portions 22a, 22a. As a result, it is integrally formed in the circumferential direction of the bottom surface portion 21 and formed in a funnel shape, and the inner surface of the continuous portion 22b between the peripheral wall piece portions 22a and 22a is a smooth concave arc surface that is not cut or cracked over the entire length. The inner peripheral surface of the peripheral wall portion 22 is formed entirely on a light reflecting surface 22c that reflects light emitted from the light source L described later. Furthermore, the inner surface of the continuous portion between the peripheral wall portion 22 and the bottom surface portion 21 is also formed into a smooth concave arc surface, preferably a concave arc surface, that is completely free of cuts and cracks.

  The inner bottom surface of the concave portion 2, that is, the inner surface of the bottom surface portion 21, serves as a light source disposing portion 23 for disposing a light source L such as a light-emitting diode. A hole 21a is provided between the front and back surfaces, and the light source L can be arranged on the light source arrangement part 23 through the through hole 21a.

  Furthermore, the recesses 2 and 2 adjacent to each other are integrally formed at the opening edge thereof via a connecting portion 3 formed in a lattice shape, and the surface of the connecting portion 3 is cut into the entire surface. Or a convex arc surface without cracks, preferably a convex arc surface.

  Therefore, the light reflecting plate A is formed with a large number of recesses 2, 2... By bulging molding in the thermoplastic resin sheet 1, and the peripheral wall piece 22 a and the bottom surface 21 are continuously provided in each recess 2. And the connecting portion 22b between the peripheral wall piece portions 22a and the connecting portion (connecting portion 3) between the recesses 2 and 2 are formed as an arc surface, preferably an arc surface, which is formed integrally on the entire surface. No cuts or cracks are formed.

  Next, a method for manufacturing the light reflecting plate A will be described. First, the light-reflective thermoplastic resin sheet used as the material of the light reflection plate A is not particularly limited as long as it can reflect light. In the thermoplastic resin sheet, inorganic materials such as titanium oxide and calcium carbonate are used. Light reflectivity can be imparted by adding a filler, but 100 parts by weight of thermoplastic resin, 10 to 100 parts by weight of titanium oxide, 0.01 to 0.8 parts by weight of primary antioxidant, and secondary oxidation. Heat comprising a thermoplastic resin composition containing 0.01 to 0.8 parts by weight of an inhibitor, 0.01 to 0.8 parts by weight of an ultraviolet absorber and 0.01 to 0.8 parts by weight of a hindered amine light stabilizer. A plastic resin sheet is preferable because it is excellent in light reflectivity and thermoformability.

  If the total light reflectivity of the light-reflective thermoplastic resin sheet is low, the light reflectivity of the light reflection plate is lowered. Therefore, 96% or more is preferable, and 97 to 100% is more preferable.

  The total light reflectance of the thermoplastic resin sheet is the light reflectance at a wavelength of 550 nm when the total reflected light measurement is performed under an incident condition of 8 ° in accordance with the measurement method B described in JIS K7105. The measurement was carried out in an environment of 20 ° C. and a relative humidity of 60%, and the value was shown as a relative value when the light reflectance when a barium sulfate plate was used as a standard reflecting plate was taken as 100.

  The thermoplastic resin is not particularly limited, and examples thereof include polyethylene resins, polyolefin resins such as polypropylene resins, polyester resins, acrylic resins such as polymethyl acrylate, polyvinyl chloride resins, and polychlorinated resins. Examples thereof include diene resins such as vinylidene resins, fluorine resins, polyether resins, polyamide resins, polyurethane resins, polybutadienes, polyolefin resins are preferable, and polypropylene resins are more preferable. In addition, a thermoplastic resin may be used independently or 2 or more types may be used together.

  Examples of the polyethylene resin include low density polyethylene, linear low density polyethylene, high density polyethylene, and medium density polyethylene.

  Examples of the polypropylene resin include homopolypropylene, ethylene-propylene copolymer, propylene-α-olefin copolymer, and the like, since the volatile component is not generated even when the light reflector is heated. preferable. Further, when the light reflecting plate is foamed, the polypropylene resin is preferably a high melt tension polypropylene resin disclosed in Japanese Patent No. 2521388 or Japanese Patent Application Laid-Open No. 2001-226510. .

  In addition, the ethylene-propylene copolymer and the propylene-α-olefin copolymer may be either a random copolymer or a block copolymer. The content of the α-olefin component in the propylene-α-olefin copolymer is preferably 0.5 to 30% by weight, and more preferably 1 to 10% by weight.

  Examples of the α-olefin include α-olefins having 4 to 10 carbon atoms, such as 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene and the like. Is mentioned.

  The titanium oxide includes a rutile type, anatase type and ilmenite type, but a rutile type is preferred. And if titanium oxide has strong photocatalytic action, it will deteriorate the thermoplastic resin and cause the light reflectivity of the light reflecting plate to decrease, so it is preferable to perform surface treatment.

  Although it does not specifically limit as the surface treatment method of the said titanium oxide, The method etc. which coat | cover with hydrous oxides, such as aluminum, silicon, titanium, zirconium, tin, etc. are mentioned.

  And, if the content of titanium oxide in the thermoplastic resin composition is small, the light reflectivity of the light reflecting plate is lowered, but at most, the light reflecting of the light reflecting plate is sufficient to meet the compounding amount of titanium oxide. In addition to the improvement in properties, the light reflecting plate is also reduced in lightness, so that it is preferably 10 to 100 parts by weight, more preferably 20 to 80 parts by weight, more preferably 30 to 65 parts by weight based on 100 parts by weight of the thermoplastic resin. Part by weight is particularly preferred.

  The primary antioxidant used in the light reflecting plate of the present invention is a stabilizer that traps radicals generated by heat or light and stops the radical reaction. As such primary antioxidant, A phenolic antioxidant is preferred because it has a high effect of suppressing a decrease in light reflectivity of the plate.

  Examples of the phenolic antioxidant include 2,6-di-t-butyl-4-methylphenol and n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl). ) Propionate, tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxymethyl] methane, tris [N- (3,5-di-t-butyl-4-hydroxybenzyl)] Isocyanurate, butylidene-1,1-bis (2-methyl-4-hydroxy-5-t-butylphenyl), triethylene glycol bis [3- (3-t-butyl-4-hydroxy-5-methylphenyl) Propionate], 3,9-bis {2- [3 (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4 8,10-tetraoxaspiro [5.5] undecane and the like, may be also alone, or two or more are used alone.

  And if content of the primary antioxidant in a thermoplastic resin composition is small, while it cannot suppress the light reflectivity fall of a light reflecting plate, at most, the light reflecting property of a light reflecting plate will not increase. Since there is no change in the suppression effect of the decrease, 0.01 to 0.8 parts by weight is preferable with respect to 100 parts by weight of the thermoplastic resin, and 0.05 to 0.5 parts by weight is more preferable.

  The secondary antioxidant used in the light reflector of the present invention ionizes hydroperoxide (ROOH), which is an intermediate of auto-oxidative degradation of thermoplastic resin caused by heat and light, to prevent auto-oxidation. Since it is a thing and the effect which suppresses the light reflectivity fall of a light reflection plate is high, phosphorus antioxidant and sulfur type antioxidant are preferable and phosphorus antioxidant is more preferable.

  Examples of the phosphorus antioxidant include tris (nonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, and bis (2,4-diphenyl). -T-butylphenyl) pentaerythritol phosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) -4,4'-biphenylenedi-phosphonite, and the like. Two or more kinds may be used in combination.

  Examples of the sulfur-based antioxidant include dilauryl-3,3′-thio-dipropionate, dimyristyl-3,3′-thio-dipropionate, distearyl-3,3′-thio-dipropionate, and pentaerythritol tetrakis. (3-laurylthio-propionate) and the like may be mentioned, and these may be used alone or in combination of two or more.

  And if there is little content of the secondary antioxidant in a thermoplastic resin composition, while it cannot suppress the light reflectivity fall of a light reflecting plate, it is light reflectivity of a light reflecting plate at most. There is no change in the effect of suppressing the decrease in the amount of light, and the light reflecting property of the light reflecting plate is decreased due to the coloring of the secondary antioxidant itself. Therefore, 0.01 to 0.8 parts by weight with respect to 100 parts by weight of the thermoplastic resin Is preferable, and 0.05 to 0.5 part by weight is more preferable.

  Furthermore, examples of the ultraviolet absorber used in the light reflecting plate of the present invention include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole and 2- [2′-hydroxy-3 ′, 5′-. Bis (α, α-dimethylbenzyl) phenyl] -benzotriazole, 2- (2′-hydroxy-3 ′, 5-di-t-butylphenyl) -benzotriazole, 2- (2′-hydroxy-3′- t-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) -5-chlorobenzotriazole, 2- (2 ′ -Hydroxy-3 ', 5'-di-t-amyl) benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole, 2,2'-methylenebis [4- (1,1 , 3,3-tetramethyl Butyl) -6- (2N-benzotriazol-2-yl) phenol], 2,4-dihydroxy-benzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4- Methoxybenzophenone-5-sulfonic acid, 2-hydroxy-4-n-octyl-benzophenone, 2-hydroxy-4-n-dodecyloxy-benzophenone, bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane, 2 , 2'-dihydroxy-4-methoxy-benzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone and other benzophenone ultraviolet absorbers, salicylate phenyl, 4-t-butylphenyl salicylate and other salicylates UV absorber, ethyl-2-sia Cyanoacrylate-based ultraviolet absorbers such as NO-3,3-diphenyl-acrylate and 2-ethylhexyl-2-cyano-3,3′-diphenyl-acrylate, 2-ethoxy-3-tert-butyl-2′-ethyl- Oxalic acid anilide ultraviolet absorbers such as oxalic acid bisanilide and 2-ethoxy-2′-ethyl-oxalic acid bisanilide, 2,4-di-t-butylphenyl-3,5-di-t-butyl-4 -Benzoate ultraviolet absorbers such as hydroxybenzoate, 2- [4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5-hydroxyphenol, 2- (2 , 4-Dihydroxyphenyl) -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2,4-bis (2-hydroxy-4- Examples include triazine-based ultraviolet absorbers such as (toxylphenyl) -6- (2,4-dibutoxyphenyl) -1,3-5-triazine, and the like, which effectively suppresses the decrease in light reflectivity of the light reflector. Therefore, a benzotriazole-based ultraviolet absorber is preferable. In addition, an ultraviolet absorber may be used independently or 2 or more types may be used together.

  In addition, if the content of the ultraviolet absorber in the thermoplastic resin composition is small, it is not possible to suppress a decrease in light reflectivity of the light reflection plate, but at most, a decrease in light reflectivity of the light reflection plate. Since there is no change in the inhibitory effect, 0.01 to 0.8 parts by weight is preferable with respect to 100 parts by weight of the thermoplastic resin, and 0.05 to 0.5 parts by weight is more preferable.

  The hindered amine light stabilizer used in the light reflector of the present invention is not particularly limited, and examples thereof include bis (2,2,6,6-tetramethyl-4-piperidinyl) sebacate and bis (N-methyl). -2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) -2- (3,5-di-t-butyl- 4-hydroxybenzyl) -2-n-butylmalonate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butane-tetracarboxylate, tetrakis (1, 2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butane-tetracarboxylate, (2,2,6,6-tetramethyl-4-piperidyl) -1,2, 3, 4 A mixture of butane-tetracarboxylate and (2,2,6,6-tetramethyl-4-tridecyl) -1,2,3,4-butane-tetracarboxylate, (1,2,2,6,6 -Pentamethyl-4-piperidyl) -1,2,3,4-butane-tetracarboxylate and (1,2,2,6,6-pentamethyl-4-tridecyl) -1,2,3,4-butane Mixture with tetracarboxylate, {2,2,6,6-tetramethyl-4-piperidyl-3,9- [2,4,8,10-tetraoxaspiro (5.5) undecane] diethyl} -1 , 2,3,4-Butane-tetracarboxylate and {2,2,6,6-tetramethyl-β, β, β ′, β′-tetramethyl-3,9- [2,4,8,10 -Tetraoxaspiro (5.5) undecane] diethyl}- , 2,3,4-butane-tetracarboxylate, {1,2,2,6,6-pentamethyl-4-piperidyl-3,9- [2,4,8,10-tetraoxaspiro ( 5.5) Undecane] diethyl} -1,2,3,4-butane-tetracarboxylate and {1,2,2,6,6-pentamethyl-β, β, β ′, β′-tetramethyl-3 , 9- [2,4,8,10-tetraoxaspiro (5.5) undecane] diethyl} -1,2,3,4-butane-tetracarboxylate, poly [6- (1,1 , 3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl], [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [(2 , 2,6,6-tetramethyl-4-piperidyl) imino], 4-hydroxy A mixture of cis-2,2,6,6-tetramethyl-1-piperidineethanol and dimethyl succinate polymer, N, N ′, N ″, N ′ ″-tetrakis {4,6-bis [butyl- (N-methyl-2,2,6,6-tetramethylpiperidin-4-yl) amino] -triazin-2-yl} -4,7-diazadecane-1,10-diamine, etc. Or two or more of them may be used in combination.

  In addition, if the content of the hindered amine light stabilizer in the thermoplastic resin composition is small, it is not possible to suppress a decrease in the light reflectivity of the light reflector, while at most, the light reflectivity of the light reflector is not sufficient. There is no change in the effect of suppressing the decrease in light, and the light reflectivity of the light reflecting plate is decreased by coloring the hindered amine light stabilizer itself, so 0.01 to 0.8 parts by weight with respect to 100 parts by weight of the thermoplastic resin Is preferable, and 0.05 to 0.5 part by weight is more preferable.

  Here, the deterioration of the thermoplastic resin is caused by the cleavage of the polymer main chain. Specifically, radicals are generated by heat, light, and the like, and the generated radicals react with oxygen to turn into peroxy radicals, drawing hydrogen from the main chain into hydroperoxides. Thereafter, hydroperoxide is decomposed by the action of heat, light, and the like, becomes an alkoxy radical, cuts the polymer main chain, and a radical is generated as the polymer main chain is cut. By repeating this reaction cycle, the polymer main chain is cleaved to lower the molecular weight, and the thermoplastic resin deteriorates. This deterioration of the thermoplastic resin causes yellowing of the thermoplastic resin, resulting in a decrease in light reflectivity of the light reflecting plate.

Furthermore, titanium oxide is activated by receiving light, oxidatively decomposes and discolors organic matter in contact with the titanium oxide, and reduces the light reflectivity of the light reflecting plate. Is irradiated with a photochemical change in the crystal, oxygen defects are increased, and purple-blue Ti ⁺³ is generated and the color is changed to dark gray.

  Therefore, although a clear mechanism has not been elucidated, the deterioration of the thermoplastic resin is caused by adding a predetermined amount of a primary antioxidant, a secondary antioxidant, an ultraviolet absorber and a hindered amine light stabilizer as described above. The yellowing and the photochemical change of titanium oxide associated with the above are suppressed to prevent the light reflectance of the light reflecting plate from decreasing.

  Specifically, by adding an ultraviolet absorber and a hindered amine light stabilizer, yellowing due to deterioration of the thermoplastic resin is prevented by the light stabilizing effect of the thermoplastic resin, and organic substances by activation of titanium oxide are prevented. The prevention of oxidative degradation and suppression of photochemical changes.

  On the other hand, as described above, the ultraviolet absorber and the hindered amine light stabilizer have the power to suppress the oxidative decomposition of the organic matter by the titanium oxide, but the suppression power is not sufficient, and the ultraviolet absorber and the hindered amine The system light stabilizer itself may be oxidized and decomposed by titanium oxide.

  Therefore, in the above-described thermoplastic resin sheet, in addition to the ultraviolet absorber and the hindered amine light stabilizer, a primary antioxidant and a secondary antioxidant are added to trap the radical reaction and ionic decomposition of the hydroperoxide. The plastic resin is light-stabilized to further prevent yellowing due to deterioration, and the oxidative decomposition of the UV absorber and the hindered amine light stabilizer by titanium oxide is prevented.

  That is, the light reflecting plate formed by thermoforming the thermoplastic resin sheet has an ultraviolet absorption by titanium oxide in addition to preventing yellowing due to deterioration of the thermoplastic resin by the primary antioxidant and the secondary antioxidant. In addition to preventing decomposition of the agent and hindered amine light stabilizer, the protected ultraviolet absorber and hindered amine light stabilizer prevent the oxidative decomposition of organic substances by titanium oxide and suppress the photochemical change. As a result, it is possible to reliably prevent a situation in which the light reflectivity that has been deteriorated in a short period of time and to maintain an excellent light reflectivity over a long period of time.

  Furthermore, you may add a copper damage inhibitor (metal deactivator) to the said thermoplastic resin composition. Thus, by adding a copper damage inhibitor to the thermoplastic resin composition, the light reflection plate comes into contact with a metal such as copper, or a heavy metal ion such as copper ion acts on the light reflection plate. However, copper ions, which are deterioration promoting factors, can be captured as chelate compounds, and when the light reflector is incorporated into various liquid crystal display devices or lighting devices, the light reflector contacts with metals such as copper. Even so, it is possible to prevent the thermoplastic resin from being deteriorated and yellowing.

  Examples of the copper damage inhibitor (metal deactivator) include hydrazine compounds such as N, N-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine, 3 -(3,5-di-tetra-butyl-4-hydroxyphenyl) propionyl dihydride and the like.

  And, if the content of the copper damage inhibitor (metal deactivator) in the thermoplastic resin composition is small, the effect of adding the copper damage inhibitor may not be manifested. Since light reflectivity may decrease, 0.1 to 3.0 parts by weight is preferable with respect to 100 parts by weight of the thermoplastic resin.

  Further, an antistatic agent may be added to the thermoplastic resin composition. By adding the antistatic agent in this way, the light reflecting plate can be prevented from being charged, dust and dirt can be prevented from adhering to the light reflecting plate, and the light reflectivity of the light reflecting plate can be lowered. Can be prevented.

  As such an antistatic agent, for example, ionomers such as polyethylene oxide, polypropylene oxide, polyethylene glycol, polyester amide, polyether ester amide, and ethylene-methacrylic acid copolymer, and fourth polymers such as polyethylene glycol methacrylate copolymer are used. A class ammonium salt, a polymer type antistatic agent such as a block copolymer having a structure in which an olefinic block and a hydrophilic block described in JP-A-2001-278985 are bonded alternately and repeatedly, an inorganic salt, a polyhydric alcohol , Metal compounds, carbon and the like. If the content of the antistatic agent excluding the polymeric antistatic agent in the thermoplastic resin composition is small, the effect of adding the antistatic agent may not be manifested. 100% by weight of thermoplastic resin because not only an effect commensurate with the addition concentration of the anti-static agent but also a decrease in the effect of the antistatic agent, or significant bleeding out, coloring and yellowing due to light may occur. 0.1 to 5.0 parts by weight is preferable.

  In addition, the content of the polymer antistatic agent in the thermoplastic resin composition is preferably 1 to 20 parts by weight with respect to 100 parts by weight of the thermoplastic resin for the same reason as described above.

  In addition to copper damage inhibitors (metal deactivators) and antistatic agents, the thermoplastic resin composition includes dispersants such as metal stearates, quenchers, lactone processing stabilizers, fluorescent whitening. An agent, a crystal nucleating agent, or the like may be added.

  The thermoplastic resin sheet having light reflectivity may be a foamed sheet or a non-foamed sheet. First, as a method for producing a thermoplastic resin foam sheet having light reflectivity, a general-purpose method is adopted. For example, thermoplastic resin, titanium oxide, primary antioxidant, secondary antioxidant, ultraviolet absorber, hindered amine A light stabilizer and a foaming agent are supplied to an extruder and melt-kneaded to obtain a foamable thermoplastic resin composition. This foamable thermoplastic resin composition is extruded and foamed from a die attached to the tip of the extruder and heated. The method of manufacturing a plastic resin foam sheet is mentioned. The die is not particularly limited as long as it is widely used in extrusion foaming, and examples thereof include a T die and an annular die.

  In the above production method, when a T die is used as the die, a thermoplastic resin foam sheet can be produced by extrusion foaming into a sheet form from an extruder, while when an annular die is used as the die. The cylindrical body is extruded and foamed from a circular die to produce a cylindrical body, and the cylindrical body is gradually expanded in diameter and then supplied to a cooling mandrel to be cooled. A thermoplastic resin foam sheet can be produced by cutting the inner and outer peripheral surfaces, opening them, and developing them.

  The blowing agent is not particularly limited, and is an organic gas such as saturated aliphatic hydrocarbons such as propane, butane and pentane, and halogenated hydrocarbons such as tetrafluoroethane, chlorodifluoroethane and difluoroethane; carbon dioxide and nitrogen gas. Gaseous inorganic compounds such as water; liquid inorganic compounds such as water; mixtures of organic acids or salts thereof with bicarbonate, such as a mixture of sodium bicarbonate and citric acid, dinitrosopentamethylenetetramine, etc. Solid foaming agents and the like are mentioned, and it is preferable to use a mixture of an organic acid or a salt thereof and bicarbonate and an organic gas, and a mixture of sodium bicarbonate and citric acid and an organic gas are used. It is more preferable to use together.

  Next, as a method for producing a non-foamed thermoplastic resin sheet having light reflectivity, a general-purpose method is adopted, for example, the above-described thermoplastic resin, titanium oxide, primary antioxidant, secondary antioxidant, ultraviolet light. An absorbent and a hindered amine light stabilizer are supplied to an extruder and melt-kneaded to obtain a thermoplastic resin composition. This thermoplastic resin composition is extruded into a sheet form from a T-die attached to the tip of the extruder to be thermoplastic. The method of manufacturing a resin non-foamed sheet is mentioned.

  Furthermore, a thermoplastic resin foam sheet or a thermoplastic resin non-foamed sheet may be laminated and integrated on one surface of the thermoplastic resin sheet to form a laminated sheet. As a method for producing such a laminated sheet, a general-purpose method is adopted. For example, (1) a thermoplastic resin foam sheet constituting a light reflecting plate and a thermoplastic resin non-foamed sheet are laminated together by a coextrusion method. A method of integrating, (2) a method of laminating and integrating the thermoplastic resin non-foamed sheet constituting the light reflecting plate and the thermoplastic resin foamed sheet by a co-extrusion method, and (3) heat constituting the light reflecting plate. Examples include a method of extruding and laminating a thermoplastic resin non-foamed sheet on one surface of a thermoplastic resin foam sheet, and a method of (4) heat laminating a thermoplastic resin non-foamed sheet on one surface of a thermoplastic resin foam sheet constituting a light reflecting plate. Since the thickness of the non-foamed sheet is easy to adjust, the above methods (1) and (2) are preferable, and among the above (1) and (2), it is more preferable to use the feed block method. Masui.

  The methods (1) and (2) will be specifically described. First, as a manufacturing apparatus, two extruders, a first extruder and a second extruder, and a co-extrusion die composed of a joining die and an annular die connected to the joining die are prepared, and the first extruder and Both second extruders are connected to the confluence die of the coextrusion die.

  Then, the thermoplastic resin and the foaming agent are supplied to the first extruder and melt-kneaded to obtain a foamable thermoplastic resin composition, while the thermoplastic resin is supplied to the second extruder and in the absence of the foaming agent. To knead to make a non-foaming thermoplastic resin.

  When the light reflecting plate is composed of a thermoplastic resin foam sheet, the first extruder is used. When the light reflecting plate is composed of a thermoplastic resin non-foamed sheet, the second extruder is used. When both the foamed sheet and the thermoplastic resin non-foamed sheet constitute a light reflecting plate, titanium oxide, primary antioxidant, secondary antioxidant, ultraviolet absorber and hindered amine are added to both the first and second extruders. Further supplying a system light stabilizer.

  Next, the foamable thermoplastic resin composition of the first extruder and the non-foamable thermoplastic resin of the second extruder are supplied to the joining die of the coextrusion die and joined together to form a foamable thermoplastic resin having an annular cross section. The foamable laminate is formed by forming a foamable laminate comprising a composition layer and a non-foamable thermoplastic resin layer laminated on either the inner or outer surface of the foamable thermoplastic resin composition layer. Is supplied to an annular die connected to a converging die and extruded and foamed from the annular die into a cylindrical shape to obtain a cylindrical foam.

  Subsequently, after gradually expanding the diameter of the cylindrical foam and supplying it to the cooling mandrel to cool the cylindrical foam, the cylindrical foam is continuously inserted between the inner and outer peripheral surfaces in the extrusion direction. The sheet is cut open to form a sheet, and the thermoplastic resin non-foamed sheet or thermoplastic resin foam sheet is laminated on one side of the thermoplastic resin foam sheet or thermoplastic resin non-foamed sheet constituting the light reflector. Thus, a laminated sheet can be obtained. In the case where titanium oxide, primary antioxidant, secondary antioxidant, ultraviolet absorber and hindered amine light stabilizer are supplied to both the first and second extruders, the thermoplastic resin foam sheet and the thermoplastic Both resin non-foamed sheets have light reflectivity.

  The ratio of the outer diameter of the inner die at the opening of the annular die to the outer diameter of the cooling mandrel on the extruder side (outer diameter of the cooling mandrel on the extruder side / outer diameter of the inner die), so-called The blow-up ratio is preferably 2.5 to 3.5.

  Then, the above-mentioned thermoplastic resin foam sheet or thermoplastic resin non-foam sheet having light reflectivity is swelled in the vertical and horizontal directions by a large number of inverted truncated quadrangular pyramid-shaped recesses 2, 2. The light reflecting plate A can be manufactured by forming and penetrating a through hole 21a for disposing the light source in the bottom surface portion 21 of the recess 2 across the front and back surfaces.

  Next, the illumination device B using the light reflecting plate A will be described. First, as shown in FIG. 3, the illuminating device B is configured such that an illuminating body C including a light reflection plate A and a light emitting diode is disposed in a housing 4. The casing 4 has a flat rectangular bottom 41 having a size larger than that of the light reflecting plate A and a rectangular frame-shaped peripheral wall extending upward from the four-side outer periphery of the bottom 41. 42. In addition, a step portion 42a is formed on the inner peripheral surface upper end portion of the peripheral wall portion 42 over the entire periphery, and the frosted glass or the optical sheet 6 can be detachably disposed on the step portion 42a. Yes. The light source of the illuminator C may be a general-purpose light source in addition to the light emitting diode.

  Further, a light source body 5 is prepared in which a large number of light emitting diodes L, L... Are arranged on a planar square substrate 51 having a size that can be laid on the bottom surface portion 41 of the housing 4. In the state where the light reflection plate A is superimposed on the light source body 5, the positions of the through holes 21 a of the recesses 2 and the positions of the light emitting diodes L of the light source body 5 are matched.

  The light source body 5 is laid on the bottom surface portion 41 of the housing 4 with the light-emitting diode L facing upward (in the opening direction of the housing 4). And the light emitting diode L of the light source body 5 is arranged in each of the light source arrangement portions 23 of the concave portion 2 through the through holes 21a of the concave portion 2 of the light reflecting plate A to constitute the illuminating body C.

  In using this lighting device B, first, a frosted glass or an optical sheet 6 is detachably disposed on the step portion 42a of the peripheral wall portion 42 of the housing 4, and the light emitting diode L is caused to emit light (FIG. 3). reference). Then, light radiated radially from the light emitting diode L and incident on the light reflecting surface 22c of the recess 2 of the light reflecting plate A is reflected once or a plurality of times by the light reflecting surface 22c, and the traveling direction is cloudy. It is directed toward the glass or optical sheet 6 and enters the frosted glass or optical sheet 6. In addition, it is preferable that the light reflection plate A of the illuminating body C and the frosted glass or the optical sheet 6 are not adhered to each other.

  At this time, the light reflecting surface 22c of the light reflecting plate A is not cut or cracked, and the bent portion 22b formed on the light reflecting surface 22c is also formed on a concave arc surface, preferably a concave arc surface. Thus, the light incident on the light reflecting surface 22c is effectively directed toward the frosted glass or the optical sheet 6 while being diffused by the light reflecting surface 22c.

  The optical sheet 6 contains a light diffusing agent such as titanium oxide that diffuses light therein, and the light incident on the optical sheet 6 is irregularly reflected by the light diffusing agent in the optical sheet 6. Alternatively, the light incident on the frosted glass is diffused and diffused by the frosted glass, and is then emitted outward from the frosted glass or the optical sheet 6. Therefore, it is in a state of shining substantially uniformly.

  Here, the light incident on the frosted glass or the optical sheet 6 is irregularly reflected on the frosted glass or the optical sheet 6, and a part of the light is reflected in the direction of the light reflecting plate A and again enters the direction of the light reflecting plate A. However, the light incident again into the light reflecting plate A is reflected by the light reflecting surface 22c of the concave portion 2 and again enters the frosted glass or the optical sheet 6, and the connecting portion 3 has a smooth convex arc surface, Preferably, it is formed in the convex circular arc surface, and light is also reflected in the frosted glass or the optical sheet 6 again in this connecting part 3 while being smoothly reflected and dispersed.

  As described above, the light emitted from the light emitting diode L is reflected not only on the light reflecting surface 22c of the concave portion 2 but also on the connecting portion 3, thereby being reflected toward the direction of the frosted glass or the optical sheet 6 while being diffused. Therefore, since the frosted glass or the optical sheet 6 is irradiated with light with a substantially uniform light beam over the entire surface, the position of the light emitting diode is hardly seen through the frosted glass or the optical sheet 6.

  And the design and the character drawn directly on the frosted glass or the optical sheet 6, or the design or the character drawn on the decorative sheet disposed on the frosted glass or the optical sheet 6, is the frosted glass or the optical sheet 6. The light radiated uniformly from the entire surface clearly and uniformly emerges and can be suitably used as an advertising device or a display device.

  In the above light reflecting plate, the case where the concave portion is formed in a reverse truncated quadrangular pyramid shape has been described, but as shown in FIG. 4, a reverse truncated polygonal pyramid shape such as a reverse truncated hexagonal pyramid shape, It may be a case of forming a reverse truncated cone shape. In this case, the concave portion 2 ′ is composed of a planar circular bottom surface portion 21 ′ and a peripheral wall portion 22 ′ extended in a state where the diameter gradually increases from the outer peripheral edge of the bottom surface portion 21 ′ toward the surface side. The inner surface of the peripheral wall portion 22 ′ is formed entirely on the light reflecting surface 22c ′, and the bottom surface portion 21 ′ is provided with a through hole 21a ′ penetrating between the front and back surfaces. Note that the inner surface of the connecting portion between the bottom surface portion 21 ′ and the peripheral wall portion 22 ′ is formed into a smooth concave arc surface, preferably a concave arc surface, that is entirely free of cuts and cracks.

  The opening edges of the recesses 2 ′, 2 ′,... Are integrated entirely through a connecting portion 3 ′ formed in a frame shape, and a cut or Cracks and the like are not formed and are formed on a smooth surface. In addition, since it is the same structure as the light reflection board A mentioned above except the shape of recessed part 2 ', the description is abbreviate | omitted.

(Example 1)
Homopolypropylene (trade name “PL500A” manufactured by Sun Allomer Co., Ltd., melt flow rate: 3.3 g / 10 min, density: 0.9 g / cm ³ ) 50 parts by weight, rutile type titanium oxide in ethylene-propylene block copolymer 50 parts by weight of a master batch (trade name “PPM 1KB662 WHT FD” manufactured by Toyo Ink Co., Ltd., ethylene-propylene block copolymer: 30% by weight, titanium oxide: 70% by weight) containing phenol, phenolic as a primary antioxidant 0.1 parts by weight of an antioxidant (trade name “IRGANOX1010” manufactured by CIBA), 0.1 part by weight of a phosphorus-based antioxidant (trade name “IRGAFOS168” manufactured by CIBA) as a secondary antioxidant, and as an ultraviolet absorber Benzotriazole UV absorber (trade name “TINUVIN326” manufactured by CIBA) 0 A thermoplastic resin composition comprising 15 parts by weight and 0.15 parts by weight of a hindered amine light stabilizer (trade name “TINUVIN111” manufactured by CIBA) is supplied to a single screw extruder having a diameter of 90 mm and melt-kneaded. After melt-kneading at 200 ° C., it is extruded from a die of a T die (sheet width: 500 mm, slit interval: 0.8 mm) attached to the tip of the extruder after being held at 190 ° C. at the tip of the extruder. A thermoplastic resin sheet having a density of 1.3 g / cm ³ was obtained by taking it up to 0.3 mm with a take-up machine.

(Example 2)
A tandem type extruder in which a second-stage single-screw extruder (caliber: 115 mm) was connected to the tip of a first-stage single-screw extruder (caliber: 90 mm) via a connecting tube was prepared. And 40 parts by weight of homopolypropylene (trade name “PF814” manufactured by Sun Allomer, melt flow rate: 2.8 g / 10 min, density: 0.9 g / cm ³ ), homopolypropylene (trade name “PL500A” manufactured by Sun Allomer), Melt flow rate: 3.3 g / 10 min, density: 0.9 g / cm ³ ) 10 parts by weight, masterbatch containing rutile titanium oxide in an ethylene-propylene block copolymer (product of Toyo Ink Co., Ltd.) Name “PPM 1KB662 WHT FD”, ethylene-propylene block copolymer: 30% by weight, titanium oxide: 70% by weight) 50 parts by weight, 1.0 part by weight of a mixture of sodium bicarbonate and citric acid as a foaming agent, primary 0.1 weight of phenolic antioxidant (trade name “IRGANOX1010” manufactured by CIBA) as an antioxidant Part by weight, 0.1 parts by weight of a phosphorus-based antioxidant (trade name “IRGAFOS168” manufactured by CIBA) as a secondary antioxidant, and a benzotriazole-based UV absorber (trade name “TINUVIN326” manufactured by CIBA) as a UV absorber A thermoplastic resin composition comprising 0.15 parts by weight and 0.15 parts by weight of a hindered amine light stabilizer (trade name “TINUVIN111” manufactured by CIBA) is supplied to the first stage extruder and melted at 200 ° C. After kneading, 1.54 parts by weight of butane (isobutane / normal butane (% by weight) = 35: 65) with respect to 100 parts by weight of the polypropylene resin is press-fitted into the first-stage extruder and further melt-kneaded and foamed. A thermoplastic resin composition was obtained.

  Subsequently, the foamable thermoplastic resin composition is continuously supplied from the first-stage single-screw extruder to the second-stage single-screw extruder through the connecting pipe to cool the foamable thermoplastic resin composition to 170 ° C. Then, it was continuously supplied to an annular die attached to the tip of the second stage single screw extruder and extruded and foamed into a cylindrical shape to continuously produce a cylindrical foam. The annular die had an inner diameter of 140 mm and a slit interval of 0.6 mm at the opening.

Thereafter, the cylindrical foam is taken up while gradually expanding the diameter, and molded along a cylindrical cooling mandrel having a diameter of 424 mm and a length of 500 mm, in which cooling water of 25 ° C. is circulated. However, after cooling by blowing air over the entire outer peripheral surface of the cylindrical foam from the air outlet of the air ring disposed in a state surrounding the cooling mandrel, the cylindrical foam is opposed to the diametrical direction. A thermoplastic resin foam sheet having a thickness of 0.5 mm and a density of 0.7 g / cm ³ was obtained by cutting, opening, and developing between the inner and outer peripheral surfaces at points.

(Example 3)
Prepare the tandem type extruder used in Example 2 and a single screw extruder with a diameter of 90 mm, and join the second stage single screw extruder of the tandem type extruder and a single screw extruder with a diameter of 90 mm together. While being connected to the die, an annular die was connected to the merging die.

Homopolypropylene (trade name “PF814” manufactured by Sun Allomer Co., Ltd., melt flow rate: 2.8 g / 10 min, density: 0.9 g / cm ³ ) 50 parts by weight, homopolypropylene (trade name “PL500A” manufactured by Sun Allomer Co., Ltd.), melt flow Late: 3.3 g / 10 min, density: 0.9 g / cm ³ ) 30 parts by weight, masterbatch containing rutile titanium oxide in ethylene-propylene block copolymer (trade name “Toyo Ink Co., Ltd.” PPM 1KB662 WHT FD ”, ethylene-propylene block copolymer: 30% by weight, titanium oxide: 70% by weight) 20 parts by weight, thermoplastic comprising 1.0 part by weight of a mixture of sodium bicarbonate and citric acid as a foaming agent After the resin composition is supplied to the first stage extruder and melt-kneaded at 200 ° C., 100 weight polypropylene resin And the foamed thermoplastic resin composition and further kneaded by press-fitting 1.16 parts by weight of butane (isobutane / n-butane (weight%) = 35:65) to the first stage of the extruder with respect to part.

  Subsequently, the foamable thermoplastic resin composition is continuously supplied from the first-stage single-screw extruder to the second-stage single-screw extruder through the connecting pipe to cool the foamable thermoplastic resin composition to 170 ° C. After that, it was continuously fed to a confluence die attached to the tip of the second stage single screw extruder.

On the other hand, homopolypropylene (trade name “PL500A” manufactured by Sun Allomer Co., Ltd., melt flow rate: 3.3 g / 10 min, density: 0.9 g / cm ³ ) 50 parts by weight, rutile type in the ethylene-propylene block copolymer. Master batch containing titanium oxide (trade name “PPM 1KB662 WHT FD”, manufactured by Toyo Ink Co., Ltd., ethylene-propylene block copolymer: 30% by weight, titanium oxide: 70% by weight) 50 parts by weight as a primary antioxidant 0.1 part by weight of a phenolic antioxidant (trade name “IRGANOX1010” manufactured by CIBA), 0.1 part by weight of a phosphorus antioxidant (trade name “IRGAFOS168” manufactured by CIBA) as a secondary antioxidant, UV absorption Benzotriazole UV absorber (trade name “TINUVIN 326 manufactured by CIBA Co., Ltd.) ) 0.15 parts by weight and hindered amine light stabilizer (trade name “TINUVIN111” manufactured by CIBA) 0.15 parts by weight of non-foaming thermoplastic resin composition is supplied to a single screw extruder having a diameter of 90 mm Then, after melt-kneading at 200 ° C., it was kept at 190 ° C. at the tip of the extruder and continuously supplied to a confluence die attached to the tip of the extruder.

  Then, a foamable thermoplastic resin composition extruded from the second single-screw extruder of the tandem extruder, and a non-foamable thermoplastic resin composition extruded from a single-screw extruder having a diameter of 90 mm A non-foaming heat layer laminated on the outer surface of a foamable thermoplastic resin composition layer having an annular cross section made of a foamable thermoplastic resin composition and joined by a joining die. A foamable laminate comprising a non-foamable thermoplastic resin composition layer comprising a plastic resin composition is formed, and the foamable laminate is supplied to an annular die connected to a merging die, and from the annular die to a cylindrical shape A cylindrical foam was obtained by extrusion foaming. The annular die had an inner diameter of 140 mm and a slit interval of 0.6 mm at the opening.

Thereafter, the cylindrical foam is taken up while gradually expanding the diameter, and molded along a cylindrical cooling mandrel having a diameter of 424 mm and a length of 500 mm, in which cooling water of 25 ° C. is circulated. However, after cooling by blowing air over the entire outer peripheral surface of the cylindrical foam from the air outlet of the air ring disposed in a state surrounding the cooling mandrel, the cylindrical foam is opposed to the diametrical direction. The laminated sheet in which the thermoplastic resin foam sheet is laminated and integrated on one surface of the thermoplastic resin non-foamed sheet constituting the light reflecting plate is obtained by cutting between the inner and outer peripheral surfaces at a point and opening and developing. . The obtained laminated sheet has an overall thickness of 0.7 mm, a thermoplastic resin non-foamed sheet thickness of 0.3 mm, a thermoplastic resin foamed sheet thickness of 0.4 mm, and an overall density of 0.8 g / cm. It was ³ .

Example 4
In the first stage of the tandem extruder, 0.1 parts by weight of a phenolic antioxidant (trade name “IRGANOX1010” manufactured by CIBA) as a primary antioxidant and a phosphorus antioxidant (as a secondary antioxidant) 0.1 part by weight of CIBA product name “IRGAFOS168”), 0.15 part by weight of benzotriazole UV absorber (trade name “TINUVIN326” manufactured by CIBA) as a UV absorber, and hindered amine light stabilizer (CIBA) A laminated sheet was obtained in the same manner as in Example 3 except that 0.15 part by weight of a trade name “TINUVIN111” manufactured by the company was further added. The obtained laminated sheet has an overall thickness of 0.7 mm, a thermoplastic resin non-foamed sheet thickness of 0.3 mm, a thermoplastic resin foamed sheet thickness of 0.4 mm, and an overall density of 0.8 g / cm. It was ³ .

(Example 5)
A thermoplastic resin sheet having a thickness of 0.3 mm and a density of 1.3 g / cm ³ was obtained in the same manner as in Example 1 except that no phenol-based antioxidant was added.

(Example 6)
A thermoplastic resin sheet having a thickness of 0.3 mm and a density of 1.3 g / cm ³ was obtained in the same manner as in Example 1 except that no phosphorylation inhibitor was added.

(Example 7)
A thermoplastic resin sheet having a thickness of 0.3 mm and a density of 1.3 g / cm ³ was obtained in the same manner as in Example 1 except that the benzotriazole-based ultraviolet absorber was not added.

(Example 8)
A thermoplastic resin sheet having a thickness of 0.3 mm and a density of 1.3 g / cm ³ was obtained in the same manner as in Example 1 except that the hindered amine light stabilizer was not added.

(Manufacture of light reflectors)
A planar square-shaped raw material sheet having a side of 64 cm was cut out from the thermoplastic resin non-foamed sheet, the thermoplastic resin foamed sheet, and the laminated sheet obtained as described above. Next, the raw material sheet is heated so that the surface thereof is 140 ° C., and the reverse truncated quadrangular pyramid-shaped concave portions 2, 2... Is formed by bulging from the rear side to the rear side, and then cutting from a predetermined location, whereby 96 concave portions 2, 2... Are continuously formed vertically and horizontally on substantially the entire surface of the sheet. A light reflector A having a flat rectangular shape (A3 size) of 7 cm was obtained. In addition, twelve recesses 2, 2,... Were formed in the long side direction and eight in the short side direction.

  The concave portion 2 of the obtained light reflection plate A is extended in a state of a flat square bottom surface portion 21 having a side of 0.6 cm and a state in which the concave portion 2 gradually expands from the outer peripheral edge of the bottom surface portion 21 toward the surface side. The inner peripheral surface of the peripheral wall portion 22 was entirely formed on the light reflecting surface 22c. The open end of the peripheral wall portion 22 was formed in a planar rectangular shape having a length of 3.2 cm and a width of 3.5 cm, and the height from the inner surface of the bottom surface portion 21 to the top of the connecting portion 3 described later was 1.6 cm.

  Further, the bent portion 22b of the peripheral wall portion 22 of the recess 2, that is, the inner surface of the connecting portion 22b between the peripheral wall piece portions 22a and 22a is a concave arc surface, and the connecting portion between the peripheral wall piece portion 22a and the bottom surface portion 21 is concave. The surface of the grid-like connecting portion 3 that connects the adjacent concave portions 2, 2 to the circular arc surface is formed as a convex arc surface. It was formed in a smooth curved surface.

  Each concave portion 2 is formed such that the long side of the opening edge is parallel to the short side of the sheet and the short side is parallel to the long side, and the concave portions 2, 2. It was integrated completely. Further, a planar square through-hole 21a having a side of 0.54 cm is provided through the bottom surface 21 of the recess 2 so as to extend between the front and back surfaces. In addition, about the laminated sheet of Example 3, 4, it thermoformed so that the recessed part 2 might be in the state opened to the thermoplastic resin non-foamed sheet surface.

(Measurement of brightness)
A backlight unit directly under the light emitting diode (trade name “FN-DLA4” manufactured by Future Light) was prepared. In this backlight unit, eight light emitting diodes L, L... Are arranged in a grid pattern on an A4 size substrate in the long side direction and in the short side direction. The operating power was 5.8W.

  This backlight unit was made into an A3 size backlight by connecting its long sides. Then, a light reflecting plate A obtained from the laminated sheet of Example 3 is prepared, and each light emitting diode L of the backlight is passed through each through hole 21a of the concave portion 2 of the light reflecting plate A. An illuminating body was produced by disposing on the inner surface of the bottom surface portion 21.

  Then, a transparent double-sided mud diffusion plate D (made by Kuraray Co., Ltd., acrylic resin extruded plate, light transmittance) at a position 50 mm away from the substrate of the backlight unit in the normal direction to the light reflecting plate A side. : 78%) and A3 size, 2 mm thick milk half diffuser E (manufactured by Mitsubishi Rayon Co., Ltd., acrylic resin extrusion plate, light transmittance: 58%) in a state of being overlapped and parallel to the substrate of the backlight unit The diffusing plate E was disposed on the light reflecting plate A side. Further, a two-dimensional luminance meter (trade name “CA-2000” manufactured by Konica Minolta Co., Ltd.) was arranged at a position 50 cm away from the intersection of the diagonal lines in plan view on the diffusion plate D in the normal direction.

  Then, all the light emitting diodes were turned on, and the in-plane luminance was measured using a two-dimensional luminance meter. Table 2 shows the maximum luminance, the minimum luminance, and the average luminance. Note that the measurement conditions were a synchronous setting of 60 Hz: 1/30, an ND filter of 1.5%, a dark color allowable value of 5.0%, and an integration count of 64 times.

  Furthermore, without thermoforming the laminated sheet of Example 3, a portion corresponding to each light emitting diode of the backlight unit penetrates a planar square-shaped through-hole having a side of 0.54 cm extending between the front and back surfaces. Set up. Then, this laminated sheet was used in place of the light reflecting plate A, the in-plane luminance was measured in the same manner as described above, and the maximum luminance, minimum luminance, and average luminance were shown in Table 2. In addition, the light radiated | emitted from a light emitting diode was irradiated to the thermoplastic resin non-foamed sheet | seat of a lamination sheet.

  Also, a black thermoplastic resin sheet (non-reflective sheet) having no reflectivity is prepared, and one side that penetrates between the front and back surfaces of the non-reflective sheet at a position corresponding to each light emitting diode of the backlight unit. Through-holes having a square shape of 0.54 cm. The in-plane luminance was measured in the same manner as described above using this non-reflective sheet instead of the light reflecting plate A, and the maximum luminance, minimum luminance and average luminance were shown in Table 2.

(Irradiation evaluation)
From the thermoplastic resin non-foamed sheet, the thermoplastic resin foam sheet and the laminated sheet prepared in each example, a test piece having a plane rectangular shape (A4 size) having a length of 29.7 cm and a width of 21 cm was cut out, and total light reflection of this test piece was performed. The rate was measured and used as the total light reflectance before light irradiation (in Table 1, it is described in the column “Before light irradiation”). The measurement of the total light reflectance of each test piece was performed as follows.

  The total light reflectance of the test piece is the relative reflectance of the light having a wavelength of 550 nm when the total reflected light measurement is performed under the incident condition of 8 ° in accordance with the measuring method B described in JIS K7105, relative to the room temperature of 20 ° C. The measurement was performed in an environment with a humidity of 60%, and the value was shown as a relative value when the light reflectance when a barium sulfate plate was used as the standard reflector was 100. In addition, 30 pieces of test pieces each were prepared for the total light reflectance of the test pieces, and the arithmetic average value of the total light reflectance of each test piece was used.

  Specifically, the total light reflectance of the test piece is changed from the Shimadzu Corporation under the trade name “UV-2450” to the ultraviolet-visible spectrophotometer, and from the Shimadzu Corporation under the trade name “ISR-2200”. The measurement was performed in combination with a commercially available integrating sphere attachment device (inner diameter: φ60 mm).

  Next, a backlight unit (product name “FN-DLA4” manufactured by Future Light) used in the above-described measurement of luminance is prepared, and is located at a position 33 mm away from the substrate of the backlight unit in the normal direction to the light emitting diode side. A test piece was placed.

  Then, after the light emitting diode of the backlight unit is turned on and the test piece is irradiated with light for 1 hour, the total light reflectance of the test piece is measured in the same manner as described above, and after 1 hour of light irradiation. It was set as the total light reflectance (in Table 1, it was described in the column of “1 h after light irradiation”). In addition, about the laminated sheet of Example 3, 4, light was irradiated to the thermoplastic resin non-foamed sheet.

  Further, after the test piece was left in a dark room at room temperature of 20 ° C. and a relative humidity of 60% for 24 hours, the total light reflectance of the test piece was measured as described above. It was set as the total reflectance (in Table 1, it is described in the column “after 24 hours”).

(Change of yellow index (YI) (ΔYI))
In the irradiation evaluation, the yellow index of each sheet before light irradiation (yellow index before light irradiation) and the yellow index of the sheet after receiving light from the light emitting diode for 1 hour in the same manner as the above-mentioned irradiation evaluation ( The yellow index after light irradiation) was measured using a spectrocolorimeter (trade name “CM-2600d” manufactured by Konica Minolta, Inc.) according to ASTM D1925. The results are shown in Table 1. The difference between the yellow index after light irradiation and the yellow index before light irradiation was calculated and used as the change in yellow index (ΔYI). A smaller yellow index change (ΔYI) indicates a smaller degree of yellowing.

It is the perspective view which showed the light reflecting plate of this invention. It is the longitudinal cross-sectional view which showed the light reflection board of this invention. It is the longitudinal cross-sectional view which showed the illuminating device using the light reflector of this invention. It is the perspective view which showed another example of the light reflection board of this invention.

Explanation of symbols

1 Thermoplastic resin sheet 2 Recess 3 Connection part
21 Bottom
21a Through hole
22 Perimeter wall
22a Perimeter wall piece
22b Connecting part (bent part)
22c Light reflecting surface
23 Light source arrangement part A Light reflector B Illumination device C Illumination body L Light source, light emitting diode

Claims (7)

A plurality of recesses formed by thermoforming a light-reflective thermoplastic resin sheet from the front surface to the back surface are formed continuously in the vertical and horizontal directions, and a light source is disposed on the inner bottom surface of the recesses. And a light reflecting plate that is formed on a light reflecting surface that reflects light emitted from the light source. The light reflecting plate according to claim 1, wherein the concave portion is formed in a reverse truncated cone shape. The light reflecting plate according to claim 1, wherein the concave portion has a reverse truncated quadrangular pyramid shape. 4. The opening edges of the recesses adjacent to each other are connected via a connecting portion, and the bent portion of the light reflecting surface of the recess and the surface of the connecting portion are formed in a curved surface. The light reflector according to 1. The thermoplastic resin sheet is 100 parts by weight of thermoplastic resin, 10 to 100 parts by weight of titanium oxide, 0.01 to 0.8 part by weight of primary antioxidant, 0.01 to 0.8 part by weight of secondary antioxidant, 2. The light reflector according to claim 1, comprising 0.01 to 0.8 part by weight of an ultraviolet absorber and 0.01 to 0.8 part by weight of a hindered amine light stabilizer. 6. The light reflection according to claim 5, wherein the thermoplastic resin is a polyolefin resin, the primary antioxidant is a phenolic antioxidant, and the secondary antioxidant is a phosphorus antioxidant. Board. An illuminating body, wherein a light emitting diode is disposed on the light source disposition portion of the light reflecting plate according to any one of claims 1 to 6.

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