Sheet for light-emitting display device, and light-emitting display device

Abstract

A light-emitting display device (50) according to the present invention is provided with: a sheet (10) for the light-emitting display device, which is provided with a base material (15) having light transmittance and including an elastic rubber body; and a light source (40) which irradiates the sheet (10) for the light-emitting display device with light. The sheet (10) for the light-emitting display device according to the present invention is provided with the base material (15) having light transmittance and including an elastic rubber body, and is used in combination with the light source (40).

Description

Sheet for light-emitting display device and light-emitting display device

[0001] The present invention relates to a sheet for a light-emitting display device used, for example, in vehicle interior materials, and a light-emitting display device including the sheet for a light-emitting display device.

[0002] In recent years, development of optical display members that use light to display information such as temperature, time, and vehicle speed inside vehicles such as automobiles has been actively promoted from the viewpoint of improving their performance. Optical display members must have excellent light transmittance in order to properly display information, and because they constitute part of the interior of the vehicle, they are required to have a luxurious feel, such as maintaining a soft feel and having excellent design.

[0003] Foams are known as flexible materials. The use of foams in interior materials can improve the tactile feel of the material. Foams are used in various industrial fields due to their flexibility, cushioning properties, and thermal insulation properties. Foams with improved light transmittance have also been developed. For example, Patent Document 1 proposes a polyolefin-based resin foam having a closed-cell structure, a total light transmittance of 15% or more, and specific ranges of shrinkage in the machine direction (MD) and transverse direction (TD), average cell diameter in the machine direction (MD), thickness, apparent density, and 25% compression hardness. Patent Document 2 proposes an acrylic-based resin foam characterized by an average cell diameter of 1.2 mm or more. In Patent Documents 1 and 2, the light transmittance of the foam is improved primarily by adjusting the average cell diameter. Patent Document 3 also proposes an insulating foam made of a thermoplastic resin having a total light transmittance of 80% or more, an expansion ratio of 5 to 100, and an average cell diameter of 1 to 15 mm. In Patent Document 3, the light transmittance of the foam is improved by using a resin with high total light transmittance, such as methyl methacrylate.

[0004] JP 2017-190375 A JP 2013-203984 A JP 08-067757 A

[0005] However, in the interior materials using the foams described in Patent Documents 1 to 3, when it is desired to transmit light from a light source such as an LED through the interior material to create a light effect on the interior material, the light transmittance may be insufficient.Furthermore, since the foam has high heat insulating properties, the heat generated by the light source may not be sufficiently dissipated.

[0006] Therefore, an object of the present invention is to provide a sheet for a light-emitting display device that has a good feel, high light transmittance, and excellent heat dissipation properties, and a light-emitting display device equipped with the sheet for a light-emitting display device.

[0007] As a result of extensive research, the present inventors have found that the above problems can be solved by providing a sheet for a light-emitting display device with a substrate containing an elastic rubber body, and have completed the present invention as described below. That is, the present invention provides the following [1] to [8]. [1] A light-emitting display device comprising: a sheet for a light-emitting display device having a substrate that is optically transparent and contains an elastic rubber body; and a light source that irradiates the sheet for a light-emitting display device with light. [2] The light-emitting display device according to the above [1], in which the rubber constituting the elastic rubber body is silicone rubber. [3] The light-emitting display device according to the above [2], in which the rubber constituting the elastic rubber body contains silicone gel. [4] The light-emitting display device according to any one of the above [1] to [3], in which the durometer hardness of the rubber constituting the elastic rubber body is 20 or more and 80 or less when measured with a Type A durometer in accordance with JIS K6253-3, or 20 or more and 90 or less when measured with a Type E durometer in accordance with JIS K6253-3. [5] The light-emitting display device according to any one of [1] to [4] above, wherein the substrate further comprises a foam, and light from the light source is irradiated onto an elastic rubber body. [6] The light-emitting display device according to any one of [1] to [5] above, wherein the sheet for a light-emitting display device further comprises a skin adhered to the substrate directly or via another layer. [7] The light-emitting display device according to any one of [1] to [6] above, wherein the sheet for a light-emitting display device is a vehicle interior material. [8] A sheet for a light-emitting display device, which has optical transparency and comprises a substrate containing an elastic rubber body, and is used in combination with a light source.

[0008] According to the present invention, it is possible to provide a sheet for a light-emitting display device that has a good feel, high light transmittance, and excellent heat dissipation properties, and a light-emitting display device that includes the sheet for a light-emitting display device.

[0009] Fig. 1 is a schematic cross-sectional view of a sheet for a light-emitting display device according to one embodiment of the present invention. Fig. 2(a) is a schematic cross-sectional view of a sheet for a light-emitting display device according to another embodiment of the present invention, and Fig. 2(b) is a schematic plan view of a sheet for a light-emitting display device according to another embodiment of the present invention. Fig. 3 is a schematic cross-sectional view of a laminate according to one embodiment of the present invention.

[0010] <Sheet for light-emitting display device> The sheet for a light-emitting display device of the present invention will be described below with reference to embodiments. Fig. 1 shows a sheet for a light-emitting display device according to one embodiment of the present invention. As shown in Fig. 1, a sheet for a light-emitting display device 10 according to one embodiment includes a substrate 15 made of an elastic rubber body 11.

[0011] The substrate 15 is made of the elastic rubber body 11, and thus has optical transparency. Therefore, the sheet 10 for a light-emitting display device can transmit light from the light source 40, which will be described later, and can effectively achieve light effects. The light source 40 is preferably disposed on the side (back surface 15B) opposite the surface 15A of the substrate 15. Furthermore, the sheet 10 for a light-emitting display device has a good feel due to the substrate 15 being made of the elastic rubber body 11. The surface 15A of the substrate 15 is the side on which light effects are produced in the sheet for a light-emitting display device, and when the sheet for a light-emitting display device is used as an interior material for a vehicle, which will be described later, for example, it is the side facing the interior.

[0012] Each of the components constituting the sheet for a light-emitting display device will be described in more detail below. [Substrate and Elastic Rubber Body] The elastic rubber body 11 is made of rubber. The elastic rubber body 11 is preferably a non-foamed body. Examples of rubber constituting the elastic rubber body 11 include silicone rubber, acrylic rubber, urethane rubber, and fluororubber. These rubbers may be used alone or in combination of two or more.

[0013] Of the above, it is preferable to use silicone rubber as the rubber for the elastic rubber body 11. Using silicone rubber for the elastic rubber body improves the tactile feel and light transmittance of the sheet for a light-emitting display device. Furthermore, because silicone rubber has high thermal conductivity, it can more efficiently dissipate heat generated by light sources such as LEDs, thereby preventing heating by the light from the light source and improving the tactile feel. From the standpoint of tactile feel and light transmittance, silicone gel is preferred among silicone rubbers, and it is preferable that the rubber constituting the elastic rubber body contains silicone gel. While not particularly limited, the silicone gel is preferably a gel-like material obtained by controlling the crosslink density of addition-type liquid silicone rubber to 1 / 5 to 1 / 10 of normal levels and hardening it. An example of a silicone gel suitable for the elastic rubber body 11 is "Pantel GEL" manufactured by Sekisui Polymatech Co., Ltd.

[0014] (Addition-Type Liquid Silicone Rubber) The addition-type liquid silicone rubber contains a vinyl group-containing organopolysiloxane as a base agent, a hydrogen organopolysiloxane as a crosslinking agent, and a platinum compound as a catalyst.

[0015] Examples of vinyl group-containing organopolysiloxanes include dimethylpolysiloxanes capped at both ends with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymers capped at both ends with dimethylvinylsiloxy groups, dimethylsiloxane-diphenylsiloxane copolymers capped at both ends with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane-diphenylsiloxane copolymers capped at both ends with dimethylvinylsiloxy groups, methyltrifluoropropylpolysiloxanes capped at both ends with dimethylvinylsiloxy groups, and methylvinylsiloxanes capped at both ends with dimethylvinylsiloxy groups. copolymer of dimethylsiloxane and methyltrifluoropropylsiloxane, copolymer of dimethylvinylsiloxy-terminated dimethylsiloxane, methyltrifluoropropylsiloxane and methylvinylsiloxane, copolymer of dimethylsiloxane and vinylmethylsiloxane both ends capped with trimethylsiloxy groups, copolymer of dimethylsiloxane and vinylmethylsiloxane both ends capped with trimethylsiloxy groups, copolymer of dimethylsiloxane, vinylmethylsiloxane and diphenylsiloxane both ends capped with trimethylsiloxy groups, copolymer of vinylmethylsiloxane and methyltrifluoropropylsiloxane both ends capped with trimethylsiloxy groups, dimethylpolysiloxane capped with methylvinylsiloxy groups, dimethylsiloxane / methylvinylsiloxane copolymer capped with trimethylsiloxy groups / dimethylvinylsiloxy groups, dimethylsiloxane / diphenylsiloxane copolymer capped with trimethylsiloxy groups / dimethylvinylsiloxy groups, dimethylsiloxane / diphenylsiloxane / methylvinylsiloxane copolymer capped with trimethylsiloxy groups / dimethylvinylsiloxy groups, methyltrifluoropropylpolysiloxane capped with trimethylsiloxy groups / dimethylvinylsiloxy groups , dimethylsiloxane / methyltrifluoropropylsiloxane copolymer terminated with terminal trimethylsiloxy groups or dimethylvinylsiloxy groups, dimethylsiloxane / methyltrifluoropropylsiloxane / methylvinylsiloxane copolymer terminated with terminal trimethylsiloxy groups or dimethylvinylsiloxy groups, dimethylpolysiloxane terminated with both terminals by methyldivinylsiloxy groups, dimethylsiloxane / methylvinylsiloxane copolymer terminated with both terminals by methyldivinylsiloxy groups, dimethylsiloxane / diphenylsiloxane copolymer terminated with both terminals by methyldivinylsiloxy groups,Both ends are blocked with methyldivinylsiloxy groups: dimethylsiloxane, methylvinylsiloxane, and diphenylsiloxane copolymer; both ends are blocked with methyldivinylsiloxy groups: methyltrifluoropropylpolysiloxane; both ends are blocked with methyldivinylsiloxy groups: dimethylsiloxane, methyltrifluoropropylsiloxane, and methylvinylsiloxane copolymer; both ends are blocked with methyldivinylsiloxy groups: dimethylsiloxane, methyltrifluoropropylsiloxane, and methylvinylsiloxane copolymer; both ends are blocked with trivinylsiloxy groups: dimethylpolysiloxane; both ends are blocked with trivinylsiloxy groups: dimethylsiloxane and methylvinylsiloxane copolymer; both ends are blocked with trivinylsiloxy groups: dimethylsiloxane and diphenylsiloxane linear diorganopolysiloxanes such as siloxane copolymers, dimethylsiloxane-methylvinylsiloxane-diphenylsiloxane copolymers both end-blocked with trivinylsiloxy groups, methyltrifluoropropylpolysiloxanes both end-blocked with trivinylsiloxy groups, dimethylsiloxane-methyltrifluoropropylsiloxane copolymers both end-blocked with trivinylsiloxy groups, and dimethylsiloxane-methyltrifluoropropylsiloxane-methylvinylsiloxane copolymers both end-blocked with trivinylsiloxy groups, and the linear diorganopolysiloxanes exemplified above each contain a small amount of organosilsesquioxane units (e.g., methylsilsesquioxane units; (CH3)SiO, 3 / 2 )-containing branched-chain organopolysiloxanes.

[0016] There are no particular restrictions on the viscosity of the vinyl group-containing organopolysiloxane, but in order to improve the handling of the silicone rubber composition obtained by mixing the silicone gel raw materials and the strength and fluidity of the resulting silicone gel, the viscosity at 23°C is preferably 50 to 100,000 mPa·s, and more preferably 100 to 10,000 mPa·s. The viscosity can be measured using a rotational viscometer.

[0017] Examples of the hydrogen organopolysiloxane include 1,1,3,3-tetramethyldisiloxane, 1,1,3,3,5,5-hexamethyltrisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, methylhydrogensiloxane cyclic polymer, methylhydrogensiloxane-dimethylsiloxane cyclic copolymer, tris(dimethylhydrogensiloxy)silylmethylsilane, tris(dimethylhydrogensiloxy)silylphenylsilane, dimethylpolysiloxane capped at both ends with dimethylhydrogensiloxy groups, methylhydrogenpolysiloxane capped at both ends with dimethylhydrogensiloxy groups, and methylhydrogensiloxane capped at both ends with dimethylhydrogensiloxy groups. Examples of suitable methylhydrogensiloxane copolymers include methylhydrogensiloxane-diphenylsiloxane copolymers both ends of which are capped with dimethylhydrogensiloxy groups, methylhydrogensiloxane-dimethylsiloxane-diphenylsiloxane copolymers both ends of which are capped with dimethylhydrogensiloxy groups, methylhydrogenpolysiloxanes both ends of which are capped with trimethylsiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymers both ends of which are capped with trimethylsiloxy groups, methylhydrogensiloxane-diphenylsiloxane copolymers both ends of which are capped with trimethylsiloxy groups, and methylhydrogensiloxane-diphenylsiloxane-dimethylsiloxane copolymers both ends of which are capped with trimethylsiloxy groups.

[0018] The viscosity of the hydrogenorganopolysiloxane is preferably 0.1 to 1,000 mPa·s, and more preferably 1 to 500 mPa·s. If the viscosity of the hydrogenorganopolysiloxane is too low, the viscosity of the resulting silicone rubber composition will also be low, resulting in poor workability and the resulting silicone gel may be too hard. If the viscosity of the hydrogenorganopolysiloxane is too high, the viscosity of the resulting silicone rubber composition will also be high, which may have an adverse effect on workability.

[0019] The amount of hydrogen organopolysiloxane blended is an amount such that the number of silicon-bonded hydrogen atoms (SiH groups) in the hydrogen organopolysiloxane is 0.01 to 3, preferably 0.05 to 2, and more preferably 0.2 to 1.5 per silicon-bonded vinyl group in the entire composition (particularly the vinyl group-containing organopolysiloxane). If the number of silicon-bonded hydrogen atoms (SiH groups) in the hydrogen organopolysiloxane is less than 0.01 per vinyl group in the entire silicone rubber composition, a silicone gel cannot be obtained. On the other hand, if the number is more than 3, the heat resistance of the silicone gel decreases.

[0020] Examples of platinum compounds include platinum black, chloroplatinic acid, alcohol-modified products of chloroplatinic acid, and complexes of chloroplatinic acid with olefins, aldehydes, vinylsiloxanes, or acetylene alcohols.

[0021] The amount of platinum compound added may be an effective amount, which can be increased or decreased as appropriate depending on the desired curing rate, but is usually in the range of 0.1 to 10,000 ppm by mass, and preferably 1 to 5,000 ppm by mass, in terms of the mass of platinum group metal atoms relative to the total amount of vinyl group-containing organopolysiloxane and hydrogenorganopolysiloxane. If this amount is too high, the heat resistance of the resulting silicone gel may decrease.

[0022] The addition-type liquid silicone rubber may further contain a reaction inhibitor to adjust the usable time. Examples of reaction inhibitors include methylvinylcyclotetrasiloxane, acetylene alcohols, siloxane-modified acetylene alcohols, and hydroperoxides.

[0023] To increase strength, the addition-type liquid silicone rubber may further contain a reinforcing material such as reinforcing silica, quartz powder, iron oxide, alumina, or vinyl group-containing silicone resin.

[0024] The addition-type liquid silicone rubber may further contain additives such as pigments, mold release agents, heat resistance agents, flame retardants, flow control agents, anti-settling agents, and adhesion improvers.

[0025] The elastic rubber body 11 can be produced by curing a rubber composition containing a rubber component, although there are no particular limitations on the method. The curing time of the rubber composition can be adjusted, for example, by the amount of catalyst added or the curing temperature. More specifically, the elastic rubber body 11 can be produced, for example, by supplying the raw materials of the rubber composition to a mixer such as a kneading device and mixing them in the mixer, obtaining a sheet-shaped rubber composition, and curing the obtained rubber composition. When curing the rubber composition, the rubber composition may be cured at room temperature; however, when curing the rubber composition in a short period of time, it is preferable to heat the rubber composition.

[0026] (Thickness) The thickness of the elastic rubber body 11 is not particularly limited, but is preferably 0.5 to 100 mm, and more preferably 1 to 50 mm. When the thickness is within this range, the sheet 10 for a light-emitting display device can be suitably used as an interior material for a vehicle.

[0027] (Light Transmittance) The elastic rubber body 11, i.e., the substrate 15, is light transmissive in the thickness direction. Because the substrate 15 is light transmissive, when light from the light source 40 is irradiated from the back surface 15B side of the light-emitting display device sheet, the light passes through the substrate 15 and can produce a light effect on the front surface 15A side of the substrate 15. Specifically, it becomes possible to display necessary information using light from the light source, or to use the light source 40 to light up the interior of the vehicle or display images.

[0028] The total light transmittance in the thickness direction of the substrate 15 may be, for example, 50% or more, preferably 70% or more, and more preferably 80% or more. A total light transmittance of 50% or more for the elastic rubber body 11 provides sufficient light transmittance for the elastic rubber body 11, making it easier for a certain amount of light emitted from the light source 40 to exit the surface 15A. The higher the total light transmittance of the substrate 15, the better. While a total light transmittance of 100% or less is sufficient, practically, it may be 99% or less, or even 98% or less. The total light transmittance of the substrate 15 can be kept within the above range by, for example, appropriately adjusting the thickness of the elastic rubber body 11, the type of rubber, and the type of additives, such as pigments and dyes, added to the rubber. However, using silicone rubber makes it easier to increase the total light transmittance. The total light transmittance can be measured, for example, using a haze meter in accordance with ASTM D1003. In addition, when only a portion of the substrate 15 is constituted by the elastic rubber body 11 as described below, the total light transmittance in the thickness direction of the substrate 15 is the total light transmittance in the area where the elastic rubber body 11 is provided.

[0029] (Durometer Hardness) The method for measuring the durometer hardness of the elastic rubber body 11 varies depending on the hardness. Generally, the durometer hardness is measured under conditions that result in a durometer hardness in the range of 20 to 90. When measured using a Type A durometer in accordance with JIS K6253-3:2012, the durometer hardness is preferably 20 to 80. When the durometer hardness of the elastic rubber body 11 is 20 to 80, the elastic rubber body 11 can be made to have both strength and a soft feel. From this perspective, the durometer hardness of the elastic rubber body 11 is more preferably 20 to 70, and even more preferably 20 to 65. Furthermore, when measured using a Type E durometer in accordance with JIS K6253-3:2012, a more flexible elastic rubber body 11 is preferably 20 to 90. When the durometer hardness of the elastic rubber body 11 is 20 to 90, the elastic rubber body 11 can be made to have both strength and a soft feel. From this viewpoint, the durometer hardness of the elastic rubber body 11 is more preferably 30 or more and 90 or less, and even more preferably 40 or more and 90 or less. The durometer hardness of the elastic rubber body 11 can be measured in accordance with JIS K6253-3:2012 using, for example, an Asker rubber hardness meter manufactured by Kobunshi Keiki Co., Ltd.

[0030] (Skin Layer) The substrate 15 may be composed of a single layer of elastic rubber body 11, and the surface of the elastic rubber body 11 may constitute the surface of the substrate 15. Alternatively, a skin layer (not shown) made of a resin layer or the like may be formed on at least one surface, and the skin layer may constitute the surface of the substrate 15. The skin layer may be made of a resin other than rubber. Examples of resins that constitute the skin layer include urethane resin and acrylic resin. The thickness of the skin layer disposed on the surface is not particularly limited, but is preferably, for example, approximately 5 to 500 μm, more preferably 8 to 300 μm, and even more preferably 10 to 100 μm. By keeping the thickness of the skin layer at a certain level or less, the flexibility of the substrate 15 is not impaired, and the tactile feel of the surface of the substrate 15 can be maintained favorably.

[0031] The entire substrate 15 may be made of elastic rubber bodies 11. Alternatively, as shown in FIG. 2( b), a region 62 made of foam bodies 12 may be provided in addition to a region 61 made of elastic rubber bodies 11. In this case, light from the light source 40 may be irradiated onto the elastic rubber bodies 11 constituting region 61. This allows the elastic rubber bodies 11 to be provided in regions of the vehicle interior material where light effects are to be performed, and the foam bodies 12 to be provided in regions where light effects are not to be performed. This reduces the weight of the substrate 15, making it suitable for use in vehicle interior materials. It also reduces the manufacturing cost of the sheet for a light-emitting display device. For example, as shown in FIG. 2( b), the foam body 12 may be provided with a hole 63, and the elastic rubber body 11 may be fitted into the hole 63. Alternatively, the foam body 12 may be provided with a notch (not shown), and the elastic rubber body 11 may be fitted into the notch.

[0032] The foam 12 is a resin foam. Examples of resins constituting the foam include polyolefin-based resins, urethane-based resins, acrylic-based resins, and elastomer-based resins. The resins used for the foam 12 may be used alone or in combination of two or more. Of the above, the foam 12 is preferably a polyolefin-based resin foam, which uses a polyolefin-based resin as the resin. Using a polyolefin-based resin for the foam improves flexibility and mechanical strength.

[0033] (Polyolefin Resin) Examples of polyolefin resins include polyethylene resin, polypropylene resin, ethylene-vinyl acetate copolymer, etc., and among these, polypropylene resin is preferred. Use of polypropylene resin makes it easier to impart heat resistance to the substrate 15.

[0034] The polyethylene resin is low-density polyethylene (density: 0.930 g / cm ３ less than 0.930 g / cm ３ 0.942g / cm or more ３ less than 0.942 g / cm ３The density of the linear low-density polyethylene is 0.870 to 0.910 g / cm ３ is preferably 0.875 to 0.907 g / cm ３ More preferably, 0.880 to 0.905 g / cm ３ is more preferable. As the polyethylene resin, a plurality of polyethylene resins may be used, and a polyethylene resin having a density outside the above-mentioned range may also be used. Examples of the ethylene-vinyl acetate copolymer used as the polyolefin resin include an ethylene-vinyl acetate copolymer containing 50% by mass or more of ethylene.

[0035] The polypropylene resin is not particularly limited, and examples thereof include propylene homopolymers (homopolypropylenes) and copolymers of propylene and other olefins. The copolymers of propylene and other olefins may be block copolymers, random copolymers, or random block copolymers, with random copolymers (random polypropylenes) being preferred. Examples of copolymers of propylene and other olefins include propylene-α-olefins containing, for example, preferably 75% by mass or more, more preferably 90% by mass or more, of propylene. Examples of other olefins copolymerized with propylene include α-olefins such as ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene, and 1-decene, with ethylene being preferred among these. Therefore, ethylene-propylene random copolymers are more preferred as random polypropylenes.

[0036] When polypropylene resin is used as the polyolefin resin, polypropylene resin may be used alone, or may be used in combination with other polyolefin resins other than polypropylene resin or resins other than polyolefin resins. For example, polyolefin resins other than polypropylene resins may be used in combination, or resins other than polyolefin resins may be used in combination. Examples of resins other than polyolefin resins include elastomer resins. Examples of elastomer resins include various rubber components such as ethylene-propylene-diene rubber (EPDM), ethylene-propylene rubber (EPM), polybutadiene rubber, polyisoprene rubber, styrene-butadiene copolymer (SBR), or styrene rubbers such as hydrogenated styrene-butadiene copolymer (HSBR). Other examples include thermoplastic elastomers such as olefin thermoplastic elastomers and styrene thermoplastic elastomers. From the viewpoint of heat resistance, the higher the content of polypropylene resin in the foam, the better. For example, the content is preferably 50 to 100 mass%, more preferably 70 to 100 mass%, and even more preferably 80 to 100 mass%, based on the total amount of resin contained in the foam.

[0037] Furthermore, from the viewpoint of being able to impart both heat resistance and flexibility, the resin constituting the foam 12 is preferably a polypropylene-based elastomer containing a polypropylene resin and a rubber component. The polypropylene resin and the rubber component may be separate or copolymerized in the polypropylene-based elastomer. Polypropylene-based elastomers are classified into reactor-type simple blend types, dynamic crosslinking types, etc. depending on the production method, but reactor-type elastomers are preferred because the domain diameter of the dispersed rubber component is small and transparency is high. Commercially available reactor-type polypropylene-based elastomers, such as "Catalloy" (manufactured by SunAllomer Co., Ltd.), can also be used.

[0038] (Foaming Agent) The foam 12 is preferably a foam obtained by foaming a foamable composition containing the resin and a foaming agent. Examples of the foaming agent include thermally decomposing foaming agents, and organic and inorganic foaming agents can be used as thermally decomposing foaming agents. Thermally decomposing foaming agents typically have a decomposition temperature higher than the melting temperature of the resin, e.g., 140 to 270°C. Specific organic foaming agents include azo compounds such as azodicarbonamide, azodicarboxylic acid metal salts (e.g., barium azodicarboxylate), and azobisisobutyronitrile; nitroso compounds such as N,N'-dinitrosopentamethylenetetramine; hydrazine derivatives such as hydrazodicarbonamide, 4,4'-oxybis(benzenesulfonylhydrazide), and toluenesulfonylhydrazide; and semicarbazide compounds such as toluenesulfonylsemicarbazide. Examples of inorganic foaming agents include ammonium carbonate, sodium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium borohydride, and anhydrous monosodium citrate. Among these, azo compounds are preferred, and azodicarbonamide is particularly preferred, from the viewpoints of obtaining fine bubbles, economy, and safety. These thermally decomposable foaming agents can be used alone or in combination of two or more. The amount of the thermally decomposable foaming agent in the foamable composition can be adjusted depending on the expansion ratio of the foam, but is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 2 to 10 parts by mass per 100 parts by mass of the resin.

[0039] However, as the foaming agent, a foaming agent other than a pyrolytic foaming agent may be used, for example, a physical foaming agent may be used. As the physical foaming agent, a high-pressure inert gas is preferably used. The inert gas is not particularly limited as long as it is inert to the resin composition and can be impregnated, and examples thereof include carbon dioxide, butane gas, nitrogen gas, and air. These gases may be used in combination. Of these, carbon dioxide and butane gas are preferred from the viewpoint of easily increasing the expansion ratio of the foam. The inert gas used for impregnation is preferably in a supercritical or subcritical state.

[0040] (Other Additives) The foam or foamable composition may contain, as needed, additives commonly used in foams, such as crosslinking agents, crosslinking aids, antioxidants, heat stabilizers, colorants, flame retardants, antistatic agents, fillers, decomposition temperature adjusters, etc. Among these, it is preferable to use antioxidants and decomposition temperature adjusters.

[0041] (Expansion ratio) Foam 12, expansion ratio is 4 to 50 cm ３ / g, and 8 to 30 cm ３ / g, and more preferably 10 to 20 cm ３ It is more preferable that the SiO2 content is 1 / g.

[0042] (Closed Cell Ratio) The foam 12 may be an open-cell foam, a semi-closed-cell foam, or a closed-cell foam, but is preferably a closed-cell foam.

[0043] A closed-cell foam is one in which most of the cells contained in the foam are closed cells, and specifically, the closed-cell ratio is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. The upper limit of the closed-cell ratio is not particularly limited, and is 100%.

[0044] The closed cell ratio can be measured according to the method of ASTM D2856 (1998). Specifically, it is recommended to measure it as follows. First, a flat square test piece with a side length of 5 cm is cut out from the foam. Then, the thickness of the test piece is measured to determine the apparent volume V of the test piece. １ Calculate the weight of the test piece W １ Next, measure the volume V occupied by the bubbles. ２ is calculated based on the following formula: The density of the matrix resin constituting the test piece is ρ (g / cm ３ ) The volume occupied by the bubbles is V ２ =V １ -W １Next, the test piece is submerged in distilled water at 23°C to a depth of 100 mm from the water surface, and a pressure of 15 kPa is applied to the test piece for 3 minutes. After that, the pressure is released in the water, and the test piece is left to stand for 1 minute. Then, the test piece is taken out of the water, and the water adhering to the surface of the test piece is removed, and the weight W of the test piece is measured. ２ The open cell rate F and closed cell rate F were measured based on the following formula: ２ Calculate the open cell ratio F １ (%) = 100 × (W ２ -W １ ) / V ２ Closed bubble rate F ２ (%) = 100 - F １

[0045] (Degree of Crosslinking) The foam 12 is preferably a crosslinked foam, and more preferably an electron beam crosslinked foam crosslinked by an electron beam. When the foam 12 is a crosslinked foam, and especially an electron beam crosslinked foam, durability, moldability, etc. are improved. The degree of crosslinking of the foam 12 is not particularly limited, but is, for example, 10 to 70 mass %, more preferably 20 to 60 mass %. By setting the degree of crosslinking of the foam 12 within the above range, it becomes easier to improve the mechanical strength, flexibility, etc. of the substrate 15. Furthermore, it becomes possible to appropriately foam the foam 12. The method for measuring the degree of crosslinking is as follows. A test piece of approximately 100 mg is taken from the foam, and the weight A (mg) of the test piece is precisely weighed. Next, this test piece is immersed in 30 cm of xylene at 120°C. ３ After immersion for 24 hours, the insoluble matter on the mesh is filtered through a 200-mesh wire netting, collected, and vacuum-dried. The weight B (mg) of the insoluble matter is then precisely weighed. The degree of crosslinking (mass%) is calculated from the obtained value using the following formula: Degree of crosslinking (mass%) = 100 × (B / A).

[0046] The foam 12 can be produced by, without particular limitation, foaming a foamable composition containing a resin component and a foaming agent with the foaming agent. In this case, foaming with the foaming agent may be performed by heating or the like. The foam 12 is preferably obtained by crosslinking the foamable composition and foaming the crosslinked foamable composition. In addition to the resin component and the foaming agent, the foamable composition may contain additives as needed.

[0047] <Laminate> The sheet 10 for a light-emitting display device may be further laminated with another member to form a laminate. One embodiment of the laminate is shown in FIG. 3. As shown in FIG. 3, the laminate 30 preferably includes the above-described substrate 15 and a skin 31 adhered to the substrate 15. The skin 31 is adhered to one surface (surface 15A) of the substrate 15. Therefore, the skin 31 can decorate the surface of the sheet 10 for a light-emitting display device, and the laminate 30 (sheet for a light-emitting display device) including the skin 31 can be suitably used, for example, as a vehicle interior material.

[0048] The surface 31 may be made of a resin sheet such as a polyvinyl chloride sheet or a sheet made of a mixed resin of polyvinyl chloride and ABS resin, a thermoplastic elastomer sheet, a woven fabric, knitted fabric, or nonwoven fabric made from natural or artificial fibers, fake leather such as artificial leather or synthetic leather, or metal. It may also be made of genuine leather or a material with a design such as leather grain or wood grain on the surface, such as a silicone stamper with an indentation transferred from stone or wood. The surface 31 may also have many holes formed therein by appropriate punching or other processing to provide light transparency.

[0049] The surface 31 is preferably optically transparent. Because the surface 31 and the elastic rubber body are optically transparent, when light from the light source 40 is irradiated from the back side of the substrate 15, the light passes through the elastic rubber body 11 (substrate 15) and the surface 31, enabling optical effects to be produced on the surface side of the sheet for a light-emitting display device (laminate). The total light transmittance of the surface 31 in the thickness direction may be, for example, 10% or more, preferably 20% or more, and more preferably 40% or more. A total light transmittance of 10% or more of the surface 31 can provide sufficient light transmittance to the surface 31, making it easier for light emitted from the light source 40 to be emitted to the surface side of the sheet for a light-emitting display device in a quantity greater than or equal to a certain amount. The total light transmittance of the surface 31 may be 100% or less, but may also be, for example, 90% or less, or 80% or less. The total light transmittance of the surface 31 can be adjusted to fall within the above range by, for example, appropriately adjusting the type of surface. Furthermore, in the case of woven fabrics, knitted fabrics, nonwoven fabrics, etc., the total light transmittance can be adjusted by adjusting the mesh size, density, etc. In addition, when punching is performed, the size of the holes, the number of holes per unit area, etc. can also be adjusted.

[0050] The skin 31 may have a printed layer or a printed film. The printed layer may be formed by printing on one side of the skin 31. The printed film may be formed by laminating on one side of the skin 31. The printed film is formed by forming a printed layer on a base film such as a polyolefin film or a polyester film such as a PET film. The printed layer may be formed by any known method such as an inkjet method, a screen printing method, or a gravure printing method. The printed layer may display, for example, a logo, a pattern, or an icon.

[0051] The skin 31 is preferably directly adhered to the surface 15A of the base material 15. However, the skin 31 does not necessarily have to be directly adhered to the base material 15, and may be adhered to the surface of the base material 15 via another layer (not shown), such as an adhesive layer.

[0052] As shown in FIG. 1, when the elastic rubber body 11 constitutes the surface 15A of the substrate 15, the skin 31 may be adhered directly to the elastic rubber body 11 or may be adhered to the elastic rubber body 11 via another layer such as an adhesive layer.

[0053] Examples of methods for adhering the skin 31 to the substrate 15 include extrusion lamination, adhesive lamination in which an adhesive is applied and then the two are bonded together, thermal lamination (thermal fusion), hot melt, high-frequency welder, and in the case of metals, electroless plating, electrolytic plating, and vapor deposition, but any method may be used for adhesion.

[0054] <Light-emitting display device> The sheet for a light-emitting display device of the present invention can be combined with a light source 40 to form a light-emitting display device 50, as shown in Figures 1, 2, and 3. The light source 40 is preferably arranged on the surface opposite to the surface 15A of the substrate 15 (i.e., on the back surface 15B side). The light source 40 irradiates light onto the sheet for a light-emitting display device 10. Light from the light source 40 arranged on the back surface 15B side passes through the sheet for a light-emitting display device, making it possible to perform various light effects on the front surface side.

[0055] The light source 40 may be any light source used as a light source for lighting devices, display devices, etc., such as a fluorescent lamp, an incandescent lamp, an LED, or an organic EL element. Among these, an LED and an organic EL element are preferred, and an LED is more preferred. An LED is also called a light-emitting diode. The light source 40 is shown as a surface light source in FIG. 1 and the like, but may also be a point light source. The size of the point light source is not particularly limited, and may be 1 cm or less. ２ It may be about 0.1 cm or less. ２ It may be of the order of magnitude of 0.001 cm or less, for example. ２ It may be 0.005 cm or more. ２ The number of light sources 40 may be one or more. In the case where there are multiple light sources 40, the multiple light sources 40 may be arranged in a specific shape to display specific information.

[0056] The light from the light source 40 may be used for various functions, such as lighting, video display, and alert display, or may be used as an illumination source for icons, logos, patterns, etc. formed by a printing layer on the surface. The light may also be used to indicate the operating position of a motion sensor, touch sensor, switch, etc. Therefore, although not shown, a switch, touch sensor, etc. may be provided on the back side of the sheet for a light-emitting display device.

[0057] For example, when indicating the operating position of a sensor, switch, etc., the operating position can be illuminated while the surrounding area of ​​the operating position is not illuminated, allowing the operating position to be recognized. In this case, the light may be flashed. Furthermore, for lighting inside the vehicle or displaying alerts, it is preferable to use multiple point light sources or area light sources. Furthermore, the lighting may be interior lighting, or lighting for in-vehicle effects (e.g., lighting in time with music).

[0058] <Uses> The sheet for a light-emitting display device of the present invention is preferably used in vehicle interior materials, and more preferably used in vehicle interior materials as a laminate 30 provided with a skin 31. The sheet for a light-emitting display device is particularly suitable for use in vehicle interior materials in the automotive field, and is preferably used to form ceiling materials, doors, instrument panels, etc. In the sheet for a light-emitting display device 10, the surface 15A of the substrate 15 is preferably arranged on the interior side, and the back surface 15B of the substrate 15 is preferably arranged opposite the interior side. The interior side is the side that will be decorated by the vehicle interior material, and is the outer peripheral surface side of the body to which the vehicle interior material is attached.

[0059] The sheet for a light-emitting display device of the present invention is preferably formed and used in a desired shape. The sheet for a light-emitting display device is suitably used as an interior material after being formed and shaped. Methods for forming the sheet for a light-emitting display device include stamping molding, vacuum forming, compression molding, injection molding, and the like. Among these, stamping molding and vacuum forming are preferred. As the vacuum forming method, either male-pull vacuum forming or female-pull vacuum forming can be used, with male-pull vacuum forming being more preferred. Furthermore, when the sheet for a light-emitting display device of the present invention is used as a vehicle interior material as described above, it is possible to create various effects inside the vehicle by causing the surface side of the sheet for a light-emitting display device to emit light using light from a light source arranged on the back side of the sheet for a light-emitting display device, or by irradiating light into the vehicle interior from the surface of the sheet for a light-emitting display device.

[0060] REFERENCE SIGNS LIST 10 Sheet for light-emitting display device 11 Elastic rubber body 12 Foam body 15 Base material 15A Surface 30 Laminate 31 Skin 40 Light source 50 Light-emitting display device

Claims

1. A light-emitting display device comprising a sheet for a light-emitting display device having light transmissibility and including an elastic rubber body, and a light source that irradiates light onto the sheet for a light-emitting display device.

2. The light-emitting display device according to claim 1, wherein the rubber constituting the elastic rubber body is silicone rubber.

3. The light-emitting display device according to claim 2, wherein the rubber constituting the elastic rubber body contains a silicone gel.

4. The light-emitting display device according to claim 1, wherein the durometer hardness of the rubber constituting the elastic rubber body is 20 or more and 80 or less when measured with a Type A durometer conforming to JIS K6253-3, or 20 or more and 90 or less when measured with a Type E durometer conforming to JIS K6253-3.

5. The light-emitting display device according to claim 1, wherein the base material further includes a foam, and the light from the light source is irradiated onto the elastic rubber body.

6. The light-emitting display device according to claim 1, wherein the sheet for a light-emitting display device further includes a skin adhered directly to the base material or via another layer.

7. The light-emitting display device according to claim 1, wherein the sheet for a light-emitting display device is an interior material for a vehicle.

8. A sheet for a light-emitting display device having light transmissibility and including an elastic rubber body, and used in combination with a light source.

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