JP2019124876A - Translucent screen - Google Patents

Abstract

To provide a translucent screen that features high brightness, good dimensional stability, and good rupture properties.SOLUTION: A translucent screen comprises a light diffusion layer disposed at least on one surface of a substrate consisting of a plurality of sheets of paper having a transparency of 50% or greater stacked together via a transparent adhesive layer(s).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transmissive screen having high brightness, good dimensional stability, and good breakability.

  At present, a so-called rear projection type transmission screen, in which an image projected from a projector is viewed from the opposite side of the projector across the screen, is widely used in place of advertising media such as posters, signs, signs, etc. is there. In recent years, the transparent screen has attracted much attention as digital signage that can project digital content that can be changed instantly, not only static but also dynamic postings, on a large screen, which does not require repositioning, and that can be dynamically displayed. There is.

  Such a rear projection type transmissive screen is often used as a so-called window display application, for example, as a digital signage that is used as a large screen screen by attaching it to a show window or the like of a store. As a rear projection type transmission screen, a screen using a polarizing film, a Fresnel lens sheet, a lenticular lens sheet or the like (for example, Patent Document 1) or a screen using a light transmitting bead having high brightness and high contrast (for example, Patent document 2) is proposed. In addition, by providing a light diffusion layer containing porous particles, a transmission screen with high resolution, low cost, and high durability (for example, Patent Document 3) is proposed, or light diffusing fine particles and a resin binder are used. Containing a part of the light diffusing fine particles from the light diffusing layer to have a haze of 80% or more, a total light transmittance of 60% or more, and a specular gloss of at least one surface of 10% or less A transmissive screen of U.S. Pat. In such applications, plastic films such as polyethylene terephthalate that do not break are used so as to withstand long-term use.

  On the other hand, rear projection type transmissive screens may be used in applications that are used in a very short time, such as display screens at event booths, and they can be removed in a relatively short time. Unlike the rear projection type transmission screen using the above-mentioned plastic film, it is desired that it be easily broken and easily discarded like paper. In addition, when it is used in stage rendition etc., performers are able to create weird effects such as breaking the screen on which the image is shown, and so on, so it is possible to use so-called Japanese paper and shoji paper which are not transmissive screens. Breakable paper may be used.

  However, some of such papers do not easily transmit light, and there is a problem that sufficient brightness can not be obtained when used as a rear projection type transmission screen. In addition, since it is paper, there is a problem that the flatness and expansion can not be obtained due to changes in temperature and humidity, and as a result, the projected image is distorted.

Japanese Patent Application Laid-Open No. 6-165095 WO 99/050710 pamphlet JP, 2006-119318, A JP 2005-024942 A

  An object of the present invention is to provide a transmissive screen having high luminance, good dimensional stability, and good breakability.

The above-mentioned subject is achieved by the following invention.
A transmissive screen having a light diffusion layer on at least one surface of a substrate, wherein the substrate has a configuration in which a plurality of papers having a transparency of 50% or more are laminated via a transparent adhesive layer. Transmission screen.

  According to the present invention, it is possible to provide a transmissive screen having high brightness, good dimensional stability, and good breakability.

Schematic sectional drawing which shows one Example of the transmissive screen of this invention Schematic sectional drawing which shows the other Example of the transmissive screen of this invention Schematic sectional view showing a conventional example of a transmission screen Schematic sectional view showing another conventional example of transmission screen

  The present invention will be described in detail below.

  FIGS. 1 and 2 show schematic cross-sectional views showing one embodiment or another embodiment of the transmission screen of the present invention, and FIGS. 3 and 4 show schematic cross-sectional views of a transmission screen of the prior art. The substrate 6a in the present invention has a configuration in which the plastic film 4b as shown in FIG. 3 is laminated via the transparent adhesive layer 5a or a configuration in which the paper 4a as shown in FIG. 4 is laminated via the opaque adhesive layer 5b. Instead, the paper 4a is laminated via the transparent adhesive layer 5a. In the transmission screen of the present invention, as shown in FIG. 1, the light diffusion layer 3 is provided only on one side of the base 6a, and although not shown, the light diffusion layer 3 is provided on both sides of the base 6a. A configuration to be provided, a configuration to provide the adhesive layer 7 on the side opposite to the light diffusion layer 3 as shown in FIG. Although not shown, it is also possible to provide an adhesive layer 7 on the light diffusion layer 3 of the transmission screen of FIG. In addition, on the adhesive layer 7, the separate base material 8 is preferably provided for the purpose of protection of this.

  The "transmission type" of the transmission screen in the present invention refers to a screen having a total light transmittance of more than 50% as defined in JIS-K7105 in a state where the separate base material is removed.

  The paper used as the base material in the present invention is characterized in that the paper has a transparency of 50% or more. The transparency in the present invention is a value represented by 100- (opacity value), and the opacity value is the opacity (%) measured by method A of JIS P 8138.

  The base material in the present invention is characterized in that a paper having a transparency of 50% or more is laminated via a transparent adhesive layer. This makes it possible to provide a transmissive screen having good dimensional stability and good fracturability.

  The paper in the present invention is not particularly limited as long as it has a transparency of 50% or more, and is produced using wood pulp, fillers, sizing agents, paper strengthening agents, dyes, etc. usually using raw materials used in papermaking as necessary. Be done. Therefore, for example, it is characterized by having a good breaking property different from plastic films such as polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, acrylic, acetyl cellulose, polyvinyl chloride and the like. Examples of such paper include high-grade paper, glassine paper, cast paper, coated paper, resin-impregnated paper, typewriter paper, condenser paper, tracing paper, impregnated tracing paper, or Japanese paper, among which , Tracing paper and impregnated tracing paper are preferred. If the transparency of the paper is less than 50%, high luminance can not be obtained.

  The tracing paper referred to in the present invention is a paper also called natural trepe or natural trepe, and natural trepe is a paper which is paper-made so that pulp fibers are highly beaten to reduce gaps between the pulps. Racing paper is a paper in which common high-quality paper is impregnated with a transparent resin having the same refractive index as cellulose.

The basis weight of the paper in the present invention is not particularly limited as long as the transparency is 50% or more, but is preferably 10 to 400 g / m ² , more preferably 40 to 300 g / m ² , and most preferably 50 It is -250 g / m < ² >. If the basis weight of the paper is too low, the light diffusion layer is likely to be wrinkled when forming the light diffusion layer, and handling may be difficult if the basis weight of the paper is too high.

  The thickness of the paper in the present invention is not particularly limited as long as the transparency is 50% or more, but is preferably 10 to 400 μm, more preferably 40 to 300 μm, and most preferably 50 to 250 μm. When the thickness of the paper is too thin, the light diffusion layer is likely to be wrinkled and difficult to handle when the light diffusion layer is provided, and when the thickness of the paper is too thick, the breaking property may be easily deteriorated.

  When the transparent adhesive layer in the present invention is coated with commercially available transparent polyethylene terephthalate at the same solid content, the difference in opacity (%) measured by method A of JIS P 8138 before and after coating is 20% or less It will be

  The transparent adhesive layer in the present invention uses a synthetic resin adhesive such as acrylic, silicone, urethane or rubber which is generally used, and a slide bead system, a slide curtain system, an extrusion system, a slot die system, A method of bonding after being applied and dried by a general coating method such as gravure roll method, air knife method, blade coating method, rod bar coating method, or a synthetic resin such as low density polyethylene, high density polyethylene or polypropylene at high temperature It is possible to appropriately use a method of melting, coating by a die method or the like, and bonding before the synthetic resin cools.

The application amount of the transparent adhesive layer in the present invention is not particularly limited as long as the above-mentioned difference in opacity (%) is 20% or less, but preferably 3 to 40 g / m ² from the viewpoint of adhesion and tearability. And more preferably 6 to 20 g / m ² .

  The transparent adhesive layer in the present invention may appropriately contain known hardeners, preservatives, surfactants, colored dyes, colored pigments, ultraviolet absorbers, antioxidants and the like.

  The light diffusing layer in the present invention contains light diffusing fine particles and can be provided on at least one surface of the substrate.

  The light diffusing fine particles contained in the light diffusing layer in the present invention can be used regardless of organic fine particles and inorganic fine particles as long as they have the ability to diffuse light, but the brightness of the image projected from the projector is In order to further improve the properties, light diffusive fine particles which are particles in which primary particles are aggregated and have an average secondary particle diameter of more than 1.0 μm are preferable, and in particular, 3.5 μm to 150 μm are more preferable. When light diffusing fine particles having an average secondary particle diameter of less than 3.5 μm are used, so-called hot spots may easily occur, in which strong light from the projector at the time of rear projection is directly visible to a viewer. If it exceeds 150 μm, the brightness of the image projected from the projector may be low. In addition, it is also preferable to use single particle dispersible light diffusing fine particles having an average primary particle diameter of 0.10 μm or more from the viewpoint of a very wide viewing angle and good visibility from both sides of the screen.

  The average primary particle diameter in the present invention can be measured by photography with a transmission electron microscope, but it is measured as a number median diameter using a laser scattering type particle size distribution analyzer (for example, LA 910 manufactured by Horiba, Ltd.) You can also The average secondary particle diameter in the present invention can be measured as the number median diameter using a laser scattering type particle size distribution analyzer (for example, LA 910 manufactured by Horiba, Ltd.).

  The refractive index of the light diffusing fine particles is preferably 1.30 or more, more preferably 1.40 or more, because the viewing angle is wide and the visibility from both sides of the screen is excellent.

  Examples of the organic fine particles include acrylic polymers, styrene-acrylic copolymers, vinyl acetate-acrylic copolymers, vinyl acetate polymers, ethylene-vinyl acetate copolymers, chlorinated polyolefin polymers, ethylene-vinyl acetate- Acrylic and other multicomponent copolymers, SBR, NBR, MBR, carboxylated SBR, carboxylated NBR, carboxylated MBR, polyvinyl chloride, polyvinylidene chloride, polyester, polyolefin, polyurethane, polymethacrylate, polytetrafluoroethylene, polymethacryl Acid methyl, polycarbonate, polyvinyl acetal resin, rosin ester resin, episulfide resin, epoxy resin, silicone resin, silicone-acrylic resin, melamine resin, etc. . Further, it is also possible to use one in which the surface of fine particles such as melamine resin and acrylic resin is coated with inorganic fine particles such as silica. Further, even when composite particles comprising such organic fine particles and a small amount of inorganic fine particles (in which the ratio of the inorganic fine particles is less than 50% by mass) are used, they can be regarded substantially as organic fine particles. Those obtained by introducing a sulfur atom for the purpose of increasing the refractive index in the monomers of these polymers, and those obtained by introducing a fluorine substituent for the purpose of improving the weather resistance or reducing the refractive index can also be used.

  Inorganic fine particles include silica, alumina, rutile titanium dioxide, anatase titanium dioxide, zinc oxide, zinc sulfide, lead white, antimony oxides, zinc antimonate, lead titanate, potassium titanate, zirconium oxide, cerium oxide, Hafnium oxide, tantalum pentoxide, niobium pentoxide, yttrium oxide, chromium oxide, tin oxide, molybdenum oxide, ATO, ITO, oxide glass such as silicate glass, phosphate glass, borate glass, etc. These composite oxides or composite sulfides can also be used widely. In addition, in the case of inorganic fine particles having photocatalytic activity such as titanium dioxide and zinc oxide, those very thin on the surface of the inorganic fine particles and coated with silica, alumina, boron or the like can also be used. Among them, it is preferable to use a wet method or gel method silica in which fine primary particles are aggregated to form secondary particles which are dispersed particles. In addition, even when composite particles composed of inorganic fine particles and a small amount of organic polymer (having a ratio of organic fine particles of less than 50% by mass) are used, they can be regarded substantially as inorganic fine particles and used.

  In the present invention, the organic fine particles and the inorganic fine particles used as the light diffusing fine particles may be used singly or in combination of two or more kinds, or both of the organic fine particles and the inorganic fine particles may be mixed and used. is there.

The content of the light diffusing fine particles of the present invention is not particularly limited, and varies depending on the relative refractive index of the light diffusing fine particles and the specific surface area per unit mass of the light diffusing fine particles calculated from the average primary particle size and specific gravity. it is preferably 0.005~150g / ^{m 2,} more preferably 0.01~12.0g / ^{m 2,} more preferably from 0.03~10.0g / ^{m 2.}

  In addition to the light diffusing fine particles, a resin binder having good adhesion to the substrate is suitably used for the light diffusing layer in the present invention. Such a resin binder is not particularly limited. Examples of hydrophilic resin binders include polyvinyl alcohol, gelatin, polyethylene oxide, polyvinyl pyrrolidone, polyacrylic acid, polyacrylamide, polyurethane, dextran, dextrin, carrageenan. (Κ, ι, λ, etc.), agar, pullulan, water-soluble polyvinyl butyral, hydroxyethyl cellulose, carboxymethyl cellulose etc. may be mentioned. Moreover, as a hydrophobic resin binder, for example, polyester resin, acrylic resin, acrylic urethane resin, polyester acrylate resin, polyurethane acrylate resin, epoxy acrylate resin, urethane resin, epoxy resin, polycarbonate resin, cellulose Transmission of epoxy resin, acetal resin, vinyl resin, polyethylene resin, polystyrene resin, polypropylene resin, polyamide resin, polyimide resin, melamine resin, phenol resin, silicone resin, fluorine resin, etc. Thermoplastic resins, thermosetting resins, ionizing radiation curable resins, etc. can be used. It is also possible to use two or more of these resin binders in combination.

  The content of the resin binder is not particularly limited as long as it is an amount capable of holding the light diffusing fine particles and adhering to the substrate, but the content is preferably 20 to 300 parts by mass with respect to 100 parts by mass of the light diffusing fine particles. More preferably, it is 30-250 mass parts, More preferably, it is 40-200 mass parts.

  A light diffusing agent can be used together with a resin binder as needed. Specific examples of the hardening agent include formaldehyde, aldehyde compounds such as glutaraldehyde, diacetyl, ketone compounds such as chloropentanedione, bis (2-chloroethyl) urea, 2-hydroxy-4,6-dichloro-1 3,5-Triazine, a compound having a reactive halogen as described in US Pat. No. 3,288,775, a divinyl sulfone, a compound having a reactive olefin as described in US Pat. No. 3,635,718, N-methylol compounds as described in U.S. Pat. No. 2,732,316, isocyanates as in U.S. Pat. No. 3,103,437, U.S. Pat. No. 3,017,280, U.S. Pat. No. 2,983, Aziridine compounds as described in No. 611, carbodiimide type compounds as described in US Pat. No. 3,100,704 Epoxy compounds as described in US Pat. No. 3,091,537, halogen carboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane, chromium alum, zirconium sulfate, borax, boric acid, boric acid salts and the like There are inorganic crosslinking agents and the like, and these can be used alone or in combination of two or more.

Dry solid coating amount of the light diffusing layer is preferably in the range of 1 to 50 g / ^{m 2,} more preferably in the range of 3~40g / ^{m 2,} in particular in the range of 5 to 30 g / ^{m 2} is preferred. In the light diffusion layer, cationic polymers, preservatives, surfactants, coloring dyes, coloring pigments, UV absorbers, antioxidants, dispersants for pigments, antifoaming agents, leveling agents, fluorescent brighteners, viscosity Stabilizers, pH adjusters and the like can also be added as appropriate.

  The light diffusion layer may be composed of two or more layers, and may be provided on one side and both sides of the substrate. In this case, the configurations of the light diffusion layers may be the same as or different from one another. In the case where there are a plurality of light diffusion layers, the light diffusion fine particles can be contained in at least one light diffusion layer.

  In the present invention, various known coating methods can be used as the coating method used for coating the light diffusion layer. For example, there are a slide bead system, a slide curtain system, an extrusion system, a slot die system, a gravure roll system, an air knife system, a blade coating system, a rod bar coating system and the like.

  In addition, an adhesive layer using a synthetic resin adhesive such as acrylic, silicone, urethane, rubber, etc., which is generally used, can be provided on the surface of the light diffusion layer of the substrate or the opposite surface. For protection, known separate substrates such as films and papers can be provided. When using the transmission screen, the separate substrate may be peeled off and the transmission screen may be used by adhering to the adherend substrate. Although there is no restriction | limiting in particular as a to-be-adhered base material, What does not bar the light transmittance of a transmissive screen is preferable.

  The transmission screen of the present invention can also be used by projecting the image of the projector from either the light diffusion layer side or the opposite side.

  EXAMPLES Hereinafter, the present invention will be described in detail by way of examples, but the contents of the present invention are not limited to the examples. In addition, a part represents the mass part of solid content or a substantial component.

Example 1
Apply a clear adhesive layer coating solution of the following composition on one side of a tracing paper with a basis weight of 45 g / m ² and a transparency of 75% using a gravure roll coater so that the solid content is 10.0 g / m ² After drying by blowing hot air at 100 ° C., the same paper was bonded to produce a substrate. Thereafter, a light diffusion layer coating solution of the following composition is coated on one surface of the substrate using a slide bead coater so that the solid content is 10.0 g / m ² , and hot air at 10 ° C. and 50 ° C. The light diffusion layer was provided by sequentially spraying and drying to prepare a transmission screen of Example 1. When the transparent adhesive layer is coated on commercially available transparent polyethylene terephthalate so as to have a solid content of 10.0 g / m ² , the opacity is measured by the method A of JIS P 8138 before and after coating. The difference was 2%.

<Transparent adhesive layer coating liquid>
Acrylic copolymer resin 100 parts Crosslinking agent 4 parts (hexamethylene diisocyanate)
The total solid concentration was adjusted with toluene so as to be 30%.

<Light diffusion layer coating liquid>
Alkali-treated gelatin 100 parts nonionic surfactant 0.3 parts (polyoxyethylene alkyl ether)
150 parts of amorphous light diffusing fine particles (P-78A: manufactured by Mizusawa Chemical Industry Co., Ltd., average secondary particle diameter 6.0 μm)
It adjusted with water so that the whole solid concentration might be 10%.

(Example 2)
A transmission screen of Example 2 was produced in the same manner as in Example 1 except that the paper of Example 1 was changed to a glassine paper having a basis weight of 25 g / m ² and a transparency of 78%.

(Example 3)
A transmission screen of Example 3 was produced in the same manner as Example 1, except that the paper of Example 1 was changed to Japanese paper having a basis weight of 18 g / m ² and a transparency of 78%.

(Example 4)
Low-density polyethylene is melted at 180 ° C. on one side of the paper of Example 1 and coated using a die coater so that the solid content is 10.0 g / m ² , before the low-density polyethylene cools down. A transmission screen of Example 4 was produced in the same manner as in Example 1 except that the same paper was laminated to produce a substrate. When the transparent adhesive layer is coated on commercially available transparent polyethylene terephthalate so as to have a solid content of 10.0 g / m ² , the opacity is measured by the method A of JIS P 8138 before and after coating. The difference was 2%.

(Example 5)
After coating and drying on one side of the same paper as in Example 1 so that the solid content of the transparent adhesive layer of Example 1 is 30.0 g / m ² , the same paper is laminated to produce a substrate except A transmission screen of Example 5 was produced in the same manner as in Example 1. When the transparent adhesive layer is coated on commercially available transparent polyethylene terephthalate so as to have a solid content of 30.0 g / m ² , the opacity is measured by the method A of JIS P 8138 before and after coating. The difference was 4%.

(Example 6)
After coating and drying on one side of the same paper as in Example 1 so that the solid content of the transparent adhesive layer of Example 1 is 3.0 g / m ² , the same paper is laminated to produce a substrate A transmission screen of Example 6 was produced in the same manner as in Example 1. When the transparent adhesive layer is coated on commercially available transparent polyethylene terephthalate so as to have a solid content of 3.0 g / m ² , the opacity is measured according to method A of JIS P 8138 before and after coating. The difference was 1%.

(Comparative example 1)
A transmission screen of Comparative Example 1 was produced in the same manner as in Example 1 except that one sheet of paper of Example 1 was used as a base material.

(Comparative example 2)
A transmission screen of Comparative Example 2 was produced in the same manner as in Example 1 except that the paper of Example 1 was changed to a coated paper (Pearl Deluxe, made by Mitsubishi Paper Mills, 120 g / m ² , transparency 6%). .

(Comparative example 3)
A transmission screen of Comparative Example 3 was produced in the same manner as in Example 1 except that the paper of Example 1 was changed to a tracing paper having a basis weight of 65 g / m ² and a transparency of 40%.

(Comparative example 4)
A transmission screen of Comparative Example 4 was produced in the same manner as in Example 1 except that the paper of Example 1 was changed to a polyethylene terephthalate film having a basis weight of 100 g / m ² and a transparency of 95%.

(Comparative example 5)
The transparent adhesive layer coating solution of Example 1 is changed to the following opaque adhesive layer coating solution, coated on one side of the same paper as in Example 1 and dried so that the solid content is 10.0 g / m ² , A transmission screen of Comparative Example 5 was produced in the same manner as in Example 1 except that the same paper was bonded to produce a substrate. When the opaque adhesive layer is coated on commercially available transparent polyethylene terephthalate so as to have a solid content of 10.0 g / m ² , the opacity is measured according to method A of JIS P 8138 before and after coating. The difference was 40%.

<Opaque adhesive layer coating solution>
Acrylic copolymer resin 100 parts carbon black dispersion 10 parts crosslinker 4 parts (hexamethylene diisocyanate)
The total solid concentration was adjusted with toluene so as to be 30%.

(Comparative example 6)
A transmissive screen of Comparative Example 6 was produced in the same manner as in Example 1 except that the light diffusion layer of Example 1 was not provided.

  When the total light transmittance defined in JIS-K 7105 of the transmission screens of Examples 1 to 6 and Comparative Examples 1 to 6 obtained was measured, Examples 1 to 6 and Comparative Examples 1, 3 and 4 were obtained. 6 was 50% or more, and Comparative Examples 2 and 5 were less than 50%.

  In addition, the transmission screens of Examples 1 to 6 and Comparative Examples 1 to 6 were cut into A3 size, and the light diffusion layer surface was formed on the surface of the transparent acrylic plate of 5 mm thick (one side of the substrate in Comparative Example 6). The tape was pasted with the outer side). A transmission screen attached to a transparent acrylic plate is vertically stood, and a digital projector (MP 515ST, manufactured by BenQ) actually projects an image parallel to the vertical line of the screen from the light diffusion layer side, and from the opposite side to the projector The image projected on the transmissive screen was observed.

<Brightness>
The image was visually observed and evaluated according to the following evaluation criteria.
:: The brightness of the image was very high, and the detail was clearly visible.
:: Although slightly inferior to the above ◎, the brightness of the image is high, and the detail was clearly visible.
Δ: The luminance of the image was a little low, and it was difficult to see the details.
X: The brightness of the image was low, and it was difficult to see the details.

<Dimensional stability>
The transmission screen attached to the transparent acrylic plate was left in an environment of 40 ° C. and 80% RH for 2 hours, and then moved to a normal temperature and humidity environment. Thereafter, an image of a white grid-like thin line was immediately projected on a black background, and distortion of the white grid-like thin line reflected on the screen was visually observed and evaluated according to the following criteria.
◎: The distortion of the white grid-like thin line is hardly noticeable.
○: The distortion of the white grid-like thin line was slightly observed but no problem.
Δ: distortion of white grid-like thin lines was observed, and a somewhat problematic level.
X: Significant white grid-like thin line distortion is observed, which is a very problematic level.

<Breakability>
The transmission type screens of Examples 1 to 6 and Comparative Examples 1 to 6 obtained were broken with a hand in the direction of application and in the direction perpendicular thereto, and the degree of breakage was visually evaluated based on the following criteria.
:: It was possible to break easily.
○: A force is required to break from the above 上 記 but no problem.
Δ: A considerable level of force is required to break and a problematic level.
X: It did not break.

  From the results of Table 1, it can be seen that the transmissive screen of the present invention can provide a transmissive screen having high brightness, good dimensional stability, and good breakability.

1 transmission type screen 2 light diffusing fine particle 3 light diffusing layer 4a paper 4b plastic film 5a transparent adhesive layer 5b opaque adhesive layer 6a base material (paper + transparent adhesive layer)
6b substrate (plastic film + transparent adhesive layer)
6c substrate (paper + opaque adhesive layer)
7 Adhesive layer 8 Separate base material

Claims (1)

  A transmission screen having a light diffusion layer on at least one surface of a base material, wherein the base material has a configuration in which a plurality of papers having a transparency of 50% or more are laminated via a transparent adhesive layer. Transparent screen.