JP2016095406A - Reflective screen - Google Patents

Abstract

[Problem] To provide a reflective screen that can express images with a soft and calm texture, has high brightness and a wide viewing angle. [Solution] A reflective screen characterized by having a base material of paper or nonwoven fabric, a synthetic resin layer having a thickness of 50 μm or less on at least one surface of the base material, and a light diffusing layer containing light diffusing fine particles and xerogel on the synthetic resin layer. [Selected Figure] Figure 1

Description

  The present invention relates to a reflective screen capable of expressing a soft and calm image, having high brightness and a wide viewing angle.

  Currently, so-called reflective screens, in which an image projected from a projector is projected onto a screen and viewed from the projector side, are becoming popular in place of advertising media such as home theaters, posters, signs, and signboards. As a conventional reflection type screen, a two-layer reflection type screen (for example, Patent Document 1) including a reflection layer for reflecting light from a projector and a light diffusion layer for diffusing reflected light, A reflective screen (for example, Patent Document 2) having a prism sheet in which a stripe-shaped prism group composed of a diffusion layer and an optically transparent resin is arranged to extend in the vertical direction has a higher luminance and an image Various reflective screens have been proposed that are clear and have a wide viewing angle.

  On the other hand, in recent years, there has been a movement such as so-called projection mapping, in which the projection effect is further doubled by projecting onto a projection object other than the conventional film screen and superimposing the texture and texture of the projection object on the image. It has come out and is getting a lot of attention. Due to such a background, in addition to the conventional reflective screen, there is a demand for a reflective screen having various textures so that a user's image can be realized. In particular, a reflective screen that can provide a softer and more calm image expression, such as traditional Japanese-style architecture and clothing, and pets with good fur, is desired in contrast to conventional film screens that express images with high reproducibility. It is rare.

  In order to obtain a soft and calm image expression, it is conceivable to use paper or non-woven fabric with that texture, but when used as a reflective screen as it is, a conventional film is used due to the appropriate irregularities on the screen surface. Compared to a reflective screen that uses a base material, the projected image can have a very soft texture, but in terms of brightness and viewing angle, it is compared to a reflective screen that has a light diffusion layer on the film base material. Clearly inferior. In addition, when paper or non-woven fabric is used as a base material for a reflective screen and a light diffusion layer is directly provided on the screen, the fiber of paper or non-woven fabric is improved in terms of brightness and viewing angle, but the light diffusion layer In this coating process, the film is stretched and contracted by the solvent of the coating liquid, thereby giving a very large undulation to the screen and distorting the image.

  On the other hand, a reflection type screen (for example, Patent Documents 3 and 4) using a non-woven fabric as a base material, having a light reflection layer or a light absorption layer on the base material, and having a light diffusion layer thereon is reported. However, there remains room for improvement in terms of screen brightness and viewing angle.

  On the other hand, for example, Patent Documents 5 and 6 report transmission screens using a light diffusion layer containing light diffusing fine particles and xerogel.

Japanese Patent Laid-Open No. 10-142699 Japanese Patent Laid-Open No. 11-38509 JP-A-9-236873 Japanese Patent Laid-Open No. 10-312027 JP 2013-182141 A JP 2013-195548 A

  An object of the present invention is to provide a reflective screen capable of expressing an image with a soft and calm texture, having high brightness and a wide viewing angle.

The object is achieved by the following invention.
(1) A paper or non-woven fabric is used as a base material, and a synthetic resin layer having a thickness of 50 μm or less is formed on at least one surface of the base material, and light diffusing fine particles and xerogel are contained on the synthetic resin layer. A reflective screen comprising a light diffusion layer.

  According to the present invention, it is possible to provide a reflective screen capable of expressing a soft and calm image and having a high luminance and a wide viewing angle.

Schematic sectional view showing an example of the reflective screen of the present invention

  The present invention is described in detail below.

  A schematic sectional view showing an example of the reflective screen of the present invention is shown in FIG. As shown in FIG. 1, the reflection type screen of the present invention has a synthetic resin layer 2 having a thickness of 50 μm or less on at least one surface of a base material 1 made of paper or non-woven fabric. By having the light diffusing layer 5 containing the light diffusing fine particles 3 and the xerogel 4 on the resin layer, the fiber of paper or nonwoven fabric is expanded and contracted by the solvent of the coating liquid in the coating process of the light diffusing layer. In addition, it is possible to provide a reflective screen 10 having a high luminance and a wide viewing angle, which can suppress the undulation of large unevenness and can display a soft and calm image without excessively distorting the image.

  The paper as the base material of the present invention is not particularly limited, and generally used paper can be used. As the pulp constituting the paper, natural pulp, recycled pulp, synthetic pulp or the like is used alone or in combination of two or more. This paper is mixed with additives such as a sizing agent, a paper strength enhancer, a filler, an antistatic agent, a fluorescent whitening agent, and a dye generally used in papermaking.

Further, the above-mentioned paper may contain a surface sizing agent, a surface paper strengthening agent, a fluorescent whitening agent, an antistatic agent, a dye, an anchor agent and the like. It is also possible to perform surface treatment such as compression by applying pressure with a calendar or the like during paper making or after paper making. The basis weight of the paper is preferably 50 to 400 g / m ² , the thickness is preferably 50 to 400 μm, and the more preferable thickness is 80 to 200 μm.

  There is no restriction | limiting in particular as the nonwoven fabric as a base material of this invention, The nonwoven fabric generally used can be used. As main fibers for forming the nonwoven fabric, polyethylene terephthalate, polybutylene terephthalate, or homopolymers such as modified polymers of these polymers and copolymers such as copolymers, homopolymers such as polypropylene, polyethylene, polystyrene, or modified polymers of these polymers, and the like Polyolefin fibers such as copolymers, polyacrylonitrile fibers such as acrylic fibers and modacrylic fibers, polyamide fibers such as nylon 6 and nylon 66, organic synthetic fibers such as polyvinyl alcohol fibers and urethane fibers, rayon Regenerated cellulose fibers such as collagen, alginic acid, chitin, etc., such as fibers spun, and semi-synthetic fibers such as acetate fibers. In addition, the main fiber in this invention shows the fiber which occupies the ratio of 50 mass% or more of the fiber which a nonwoven fabric contains.

  In addition, as the main fiber forming the nonwoven fabric, it is also possible to use a heat-sealing fiber, and as the heat-sealing fiber, a low-melting-type polyethylene terephthalate fiber, polyacrylonitrile fiber, polyamide fiber, polyethylene fiber, etc. Examples thereof include fibers, polypropylene fibers, and the like, and core-sheath fibers having low melting point fibers of these fibers as sheath components and high melting point fibers as core components, and side-by-side one component being low melting point fibers.

These nonwoven fabrics are roughly classified by the production method, and wet nonwoven fabrics obtained by a wet papermaking method, or dry nonwoven fabrics by stitch bond method, spun bond method, melt blow method, thermal bond method, etc., or wet nonwoven fabrics or dry nonwoven fabrics are used. There is a spunlace nonwoven fabric, and a spunlace nonwoven fabric using a wet nonwoven fabric or a dry nonwoven fabric is preferably used from the viewpoint of the strength and texture of the reflective screen. The base material may be composed of two or more nonwoven fabric layers. The basis weight of the nonwoven fabric is preferably 50 to 400 g / m ² , the thickness is preferably 50 to 400 μm, and the more preferable thickness is 80 to 200 μm.

  In the present invention, the synthetic resin contained in the synthetic resin layer includes, for example, polyethylene terephthalate resin, polypropylene resin, polyethylene resin, diacetate resin, triacetate resin, polycarbonate resin, polyvinyl chloride resin, polyimide resin, cellophane, celluloid, and other plastics. Examples include resin films and synthetic rubbers.

  The synthetic resin layer preferably contains a white pigment such as titanium oxide, zinc oxide, talc, calcium carbonate, and various kinds of antioxidants, color pigments and dyes, fluorescent whitening agents, ultraviolet absorbers, and the like. Additives can also be added in appropriate combinations.

  The synthetic resin layer of the present invention is obtained by subjecting a running substrate to activation treatment such as corona discharge treatment and flame treatment as necessary, and then heat-melting the resin by an extruder on the base paper and a cooling roll. Extruded in the form of a film, pressed and cooled, extruded and coated by cooling, synthetic resin film pre-manufactured by stretching process such as biaxial stretching process and heated polyethylene resin etc. in between It can be provided on the base material using an existing method such as a polyethylene laminating method for adhering or a dry laminating method for adhering with a synthetic resin adhesive such as an acrylic resin. Among these, the extrusion coating method of polyethylene resin can maintain the texture of the substrate.

  The thickness of the synthetic resin layer in the present invention is 50 μm or less. If it exceeds 50 μm, it becomes difficult to obtain the texture of the base material, and it is impossible to express a soft and calm texture. The preferred thickness of the synthetic resin layer is 40 μm or less, more preferably 30 μm or less. Moreover, it is preferable that a minimum is 3 micrometers or more.

  The surface of the synthetic resin layer may be subjected to an easy adhesion treatment for the purpose of improving the adhesiveness with the light diffusion layer, or may be provided with a separate easy adhesion layer.

  The light diffusion layer in the present invention contains light diffusing fine particles and xerogel. As a method for forming the light diffusing layer, it is preferable to apply and form a coating liquid containing light diffusing fine particles on the synthetic resin layer from the viewpoint of obtaining a uniform light diffusing layer. When applying a coating solution containing light diffusing fine particles, a resin binder that binds the light diffusing fine particles is generally used. A coating solution containing light diffusing fine particles and a resin binder is diluted with an organic solvent or water for the purpose of adjusting the viscosity for ensuring coating properties, and is applied to a support and dried, or is applied to a photocurable resin or an electron. For example, a wire curable resin may be coated without a solvent as a resin binder. In the light diffusion layer coated by such a method, since the refractive index of both the resin binder and the light diffusing fine particles is generally around 1.50, the relative refractive index of the light diffusing fine particles with respect to the resin binder is It becomes low and efficient light diffusion hardly occurs. On the other hand, the light diffusion layer in which the light diffusing fine particles are supported by the xerogel has a xerogel void (air having a refractive index of 1.0) on the surface of the light diffusing fine particles, and the relative refraction of the light diffusing fine particles with respect to the air. Since the rate is very high, the light diffusing fine particles can be efficiently diffused, and a reflective screen with a wide viewing angle can be obtained. In addition, since the light diffusion layer is highly transparent, it is possible to express images with a soft and calm texture.

  The light diffusing fine particles contained in the light diffusing layer in the present invention may be any organic fine particles or inorganic fine particles as long as they have the ability to diffuse light, but the viewing angle of the image projected from the projector Is very wide, so that light-diffusing fine particles with a single particle dispersibility with an average primary particle diameter of 0.10 μm or more, or a secondary aggregated particle diameter with an average secondary particle diameter exceeding 1.0 μm It is preferable to contain diffusible fine particles (hereinafter referred to as aggregated particle dispersible light diffusing fine particles). The upper limit of the average primary particle diameter of the single particle dispersible light diffusing fine particles is preferably 200 μm or less. The upper limit of the average secondary particle diameter of the aggregated particle-dispersible light diffusing fine particles is preferably 200 μm.

  The average primary particle diameter as used in the present invention can be measured by photography using a reflection electron microscope. In the case of single particle dispersible light diffusing fine particles, a laser scattering type particle size distribution meter (for example, Horiba It can also be measured as the number median diameter using LA 910). The average secondary particle diameter of the light diffusing fine particles having agglomerated particle dispersibility can be measured as a number median diameter using a laser scattering type particle size distribution meter (for example, LA910 manufactured by Horiba, Ltd.).

  The refractive index of the light diffusing fine particles is preferably 1.30 or more. Further, when it exceeds 1.55, a reflective screen having a particularly wide viewing angle can be obtained, which is preferable.

  Examples of the organic fine particles include acrylic polymer, styrene-acrylic copolymer, vinyl acetate-acrylic copolymer, vinyl acetate polymer, ethylene-vinyl acetate copolymer, chlorinated polyolefin polymer, ethylene-vinyl acetate- Multi-component copolymers such as acrylic, SBR, NBR, MBR, carboxylated SBR, carboxylated NBR, carboxylated MBR, polyvinyl chloride, polyvinylidene chloride, polyester, polyolefin, polyurethane, polymethacrylate, polytetrafluoroethylene, polymethacryl It can be selected widely from conventionally known ones such as methyl acid, polycarbonate, polyvinyl acetal resin, rosin ester resin, episulfide resin, epoxy resin, silicone resin, silicone-acrylic resin, melamine resin, etc. . Further, composite particles in which the surface of fine particles such as melamine resin and acrylic resin are coated with inorganic fine particles such as silica can also be used. Further, even when composite particles composed of such organic fine particles and a small amount of inorganic fine particles (in which the proportion of inorganic fine particles is less than 50% by mass) are used, it can be substantially regarded as organic fine particles and used. Those in which a sulfur atom is introduced into the monomer of these polymers for the purpose of increasing the refractive index, and those in which a fluorine substituent is introduced to improve the weather resistance or lower 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 widely used. In the case of inorganic fine particles having photocatalytic activity, such as titanium oxide and zinc oxide, those having a very thin surface coated with silica, alumina, boron or the like can be used. Further, even when composite particles composed of inorganic fine particles and a small amount of organic polymer (the proportion of organic fine particles is less than 50% by mass) are used, they can be regarded as inorganic fine particles substantially. The inorganic fine particles used as the light diffusing fine particles are preferably aggregated particle-dispersible inorganic fine particles.

  In the present invention, the organic fine particles and the inorganic fine particles used as the light diffusing fine particles can be used singly or as a mixture of a plurality of types, and both the organic fine particles and the inorganic fine particles can be used in combination. is there.

In the present invention, the amount of the light diffusing fine particles contained in the light diffusing layer is not particularly limited, and per unit mass of the light diffusing fine particles calculated from the relative refractive index of the light diffusing fine particles and the average primary particle diameter and specific gravity. It varies depending the specific surface area of a 0.005~15.0g / ^{m 2,} preferably not 0.01~12.0g / ^{m 2,} more preferably a 0.03~10.0g / ^{m 2.}

  Next, the xerogel contained in the light diffusion layer will be described.

  The xerogel referred to in the present invention is a gel that has lost its internal solvent due to evaporation or the like and has a network structure with voids. The porosity of the light diffusion layer in which the light diffusing fine particles are held by the xerogel is 40% or more. Is preferable, and 50% or more is more preferable.

The porosity is defined by the following formula. Here, the void volume V is measured and processed using a mercury porosimeter (measuring instrument name: Autopore II 9220, manufacturer micromeritics instrument corporation), and the cumulative pore volume (ml / g) from 3 nm to 400 nm of the pore radius in the light diffusion layer. Can be obtained as a numerical value per unit area (square meter) by multiplying by the dry solid content (g / square meter) of the light diffusion layer. The coating layer thickness T can be obtained by photographing the cross section of the light diffusion layer with an electron microscope and measuring it.
P = (V / T) × 100 (%)
P: Porosity (%)
V: void volume (ml / m ² )
T: Coating layer thickness (μm)

  In the present invention, the xerogel is preferably composed of inorganic fine particles and a resin binder, and more preferably composed of inorganic fine particles having an average primary particle diameter of 18 nm or less and a resin binder. If the average primary particle diameter exceeds 18 nm, the transparency of the light diffusion layer may be reduced and sufficient luminance may not be obtained. Moreover, it is preferable that the inorganic fine particles constituting the xerogel of the present invention have a secondary aggregated particle size with an average secondary particle size of 500 nm or less. If the average secondary particle diameter exceeds 500 nm, the transparency of the light diffusion layer may be lowered and sufficient luminance may not be obtained. In the case of inorganic fine particles having a secondary agglomerated particle size, the average primary particle size referred to in the present invention can be measured by photography using a reflection electron microscope, and the average secondary particle size is a laser scattering particle size. It can be measured as the number median diameter using a distribution meter (for example, LA910 manufactured by Horiba, Ltd.).

  Examples of the inorganic fine particles in the present invention include various known fine particles such as amorphous synthetic silica, alumina, alumina hydrate, calcium carbonate, magnesium carbonate, and titanium dioxide. Silica, alumina or alumina hydrate is preferred.

  Amorphous synthetic silica can be roughly classified into wet method silica, gas phase method silica, and others depending on the production method. Wet method silica is further classified into precipitation method silica, gel method silica, and sol method silica according to the production method. Precipitated silica is produced by reacting sodium silicate and sulfuric acid under alkaline conditions, and the silica particles that have grown are agglomerated and settled, and are then commercialized through the steps of filtration, washing, drying, pulverization and classification. Precipitated silica is commercially available, for example, from Tosoh Silica Co., Ltd. as a nip seal and from Tokuyama Co., Ltd. as a Toxeal. Gel silica is produced by reacting sodium silicate and sulfuric acid under acidic conditions. During aging, the microparticles dissolve and reprecipitate so as to bind the other primary particles, so that the distinct primary particles disappear and form relatively hard aggregated particles having an internal void structure. For example, it is commercially available as nip gel from Tosoh Silica Co., Ltd., and as syloid and silo jet from Grace Japan Co., Ltd. The sol method silica is also called colloidal silica, and is obtained by heating and aging silica sol obtained through metathesis of sodium silicate acid or the like through an ion exchange resin layer, and is commercially available as, for example, Snowtex from Nissan Chemical Industries, Ltd. .

  Vapor phase silica is also called a dry method as opposed to a wet method, and is generally made by a flame hydrolysis method. Specifically, a method of making silicon tetrachloride by burning with hydrogen and oxygen is generally known, but silanes such as methyltrichlorosilane and trichlorosilane can be used alone or in silicon tetrachloride instead of silicon tetrachloride. Can be used in a mixed state. Vapor phase silica is commercially available as Aerosil from Nippon Aerosil Co., Ltd. and QS type from Tokuyama Co., Ltd.

In the present invention, gas phase method silica can be preferably used. The average primary particle diameter of the vapor phase silica used in the present invention is preferably 18 nm or less, and in order to obtain higher luminance, the average primary particle diameter is 3 to 15 nm and the specific surface area by the BET method is 200 m ^2. / G or more. The average primary particle diameter as used in the present invention is an average particle diameter obtained by measuring the diameter of a circle equal to the projected area of each of the 100 primary particles existing within a certain area by observation with an electron microscope. The BET method referred to in the present invention is one of the powder surface area measurement methods by the vapor phase adsorption method, and is a method for obtaining the total surface area, that is, the specific surface area of a 1 g sample from the adsorption isotherm. Usually, as the adsorbed gas, a large amount of nitrogen gas is used, and the method of measuring the amount of adsorption from the change in pressure or volume of the gas to be adsorbed is most often used. The most prominent expression for expressing the isotherm of multimolecular adsorption is the Brunauer, Emmett, and Teller formula, called the BET formula, which is widely used for determining the surface area. The adsorption amount is obtained based on the BET equation, and the surface area is obtained by multiplying the area occupied by one adsorbed molecule on the surface.

  Vapor phase silica is preferably dispersed in the presence of a cationic compound. Thereby, the light-diffusion layer with a high porosity is obtained, and the effect excellent in visibility is obtained. As a dispersion method, gas phase method silica and a dispersion medium are premixed by ordinary propeller stirring, turbine type stirring, homomixer type stirring, etc., and then a media mill such as a ball mill, a bead mill, a sand grinder, a high pressure homogenizer, an ultrahigh pressure, etc. It is preferable to perform dispersion using a pressure disperser such as a homogenizer, an ultrasonic disperser, a thin film swirl disperser, or the like.

  In the present invention, wet-process silica in which the average secondary particle diameter is pulverized to 500 nm or less can also be preferably used. As the wet method silica used here, precipitation method silica or gel method silica is preferable, and precipitation method silica is particularly preferable. The wet process silica particles used in the present invention are preferably wet process silica particles having an average primary particle diameter of 18 nm or less and an average aggregate particle diameter of 5 to 50 μm, and this is pulverized in the presence of a cationic compound. It is preferable to use the wet process silica fine particles.

  As the alumina used in the present invention, γ-alumina which is a γ-type crystal of aluminum oxide is preferable, and among them, a δ group crystal is preferable. γ-alumina can make primary particles as small as about 10 nm. Usually, secondary particles of thousands to tens of thousands of nanometers are averaged by ultrasonic, high-pressure homogenizer, counter collision type jet crusher, etc. What grind | pulverized the particle diameter to 500 nm or less, Preferably about 20-300 nm can be used.

The alumina hydrate of the present invention is represented by a constitutive formula of Al ₂ O ₃ .nH ₂ O (n = 1 to 3). The alumina hydrate can be obtained by a known production method such as hydrolysis of aluminum alkoxide such as aluminum isopropoxide, neutralization of aluminum salt with alkali, hydrolysis of aluminate and the like.

  The above-mentioned alumina and alumina hydrate used in the invention are used in the form of a dispersion dispersed by a known dispersant such as acetic acid, lactic acid, formic acid, nitric acid and the like.

  Two or more kinds of inorganic fine particles may be used in combination from the inorganic fine particles described above. For example, combined use of pulverized wet method silica and vapor phase method silica, combined use of finely pulverized wet method silica and alumina or alumina hydrate, and combined use of vapor phase method silica and alumina or alumina hydrate. . The ratio in the case of this combined use is preferably in the range of 7: 3 to 3: 7 in any aspect.

  In the present invention, the resin binder used together with the inorganic fine particles constituting the xerogel is not particularly limited, but a hydrophilic resin binder having high transparency is preferably used. For example, polyvinyl alcohol, gelatin, polyethylene oxide, polyvinyl pyrrolidone, polyacrylic acid, polyacrylamide, polyurethane, dextran, dextrin, carrageenan (κ, ι, λ, etc.), agar, pullulan, water-soluble polyvinyl butyral, hydroxyethylcellulose, carboxymethylcellulose Etc. Two or more of these hydrophilic resin binders can be used in combination. A preferred hydrophilic resin binder is completely or partially saponified polyvinyl alcohol or cation-modified polyvinyl alcohol.

  The content of the resin binder constituting the xerogel is preferably 3 to 100% by mass, more preferably 3 to 85% by mass, and further preferably 5 to 70% by mass with respect to the inorganic fine particles constituting the xerogel. . As a result, a wide viewing angle can be obtained. Moreover, it is preferable that it is 0.1-200 mass% with respect to the inorganic fine particle which comprises xerogel, and, as for the light diffusable fine particle mentioned above, it is especially preferable that it is 0.3-150 mass%.

  The light diffusion layer can contain a hardening agent together with the resin binder constituting the xerogel as necessary. Specific examples of the hardener include aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and 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, divinyl sulfone, a compound having a reactive olefin as described in US Pat. No. 3,635,718, N-methylol compounds as described in US Pat. No. 2,732,316, isocyanates as described in US Pat. No. 3,103,437, US Pat. No. 3,017,280, US Pat. No. 2,983 Aziridine compounds as described in US Pat. No. 611, carbodiimide compounds as described in US Pat. No. 3,100,704 , Epoxy compounds as described in U.S. Pat. No. 3,091,537, halogen carboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane, chromium alum, zirconium sulfate, borax, boric acid and borates. There exist inorganic crosslinking agents etc., and these can be used 1 type or in combination of 2 or more types.

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. The light diffusion layer further includes cationic polymers, preservatives, surfactants, colored dyes, colored pigments, UV absorbers, antioxidants, pigment dispersants, antifoaming agents, leveling agents, fluorescent whitening agents, viscosity stability An agent, a pH adjuster, etc. can also be contained.

  The light diffusion layer may be composed of two or more layers. In this case, the structures of the light diffusion layers may be the same or different from each other. When there are a plurality of light diffusion layers, the light diffusing 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. Examples include a slide bead method, a slide curtain method, an extrusion method, a slot die method, a gravure roll method, an air knife method, a blade coating method, and a rod bar coating method.

  In the present invention, an adhesive layer can be provided on the surface of the substrate opposite to the light diffusion layer. Thus, the reflective screen which provided the adhesion layer can have well-known separate base materials, such as a film and paper, on an adhesion layer for protection of an adhesion layer. When the reflective screen is used, the separate substrate is peeled off and the reflective screen is adhered to the adherend substrate. In addition, such an adhesive layer can use commonly used synthetic resin adhesives such as acrylic, silicone, urethane, rubber, etc., and the separate substrate is, for example, polyethylene terephthalate, polybutylene terephthalate, Polyethylene naphthalate, polycarbonate, polypropylene, polyethylene, polyarylate, acrylic, acetyl cellulose, polyvinyl chloride, and the like can be used.

  As a coating method used for coating the adhesive layer in the present invention, various known coating methods can be used. For example, there are a slot die method, a gravure roll method, an air knife method, a blade coating method, a rod bar coating method, and the like.

  The separation substrate in the present invention is a known film or paper having a release treatment such as silicone resin processing applied to the surface to be bonded to the adhesion layer so that the adhesion layer does not remain on the separation substrate when it is peeled off. A substrate can be used. In consideration of the influence on the curl, the thickness is preferably 1.0 to 100 μm, more preferably 5.0 to 50 μm.

  In the present invention, a protective substrate can be provided on the surface of the light diffusion layer for the purpose of protecting the light diffusion layer. If necessary, the protective substrate is peeled off during projection. As the protective substrate, a known substrate such as a film or paper having a pressure-sensitive adhesive layer adjusted so that no adhesive remains on the reflective screen side when peeled can be used. In addition, since it peels and uses finally, considering the influence on curl, 1.0-100 micrometers is preferable and, as for the thickness of a protection base material, 5.0-50 micrometers is more preferable.

  In the present invention, the surface of the light diffusion layer may have a known antireflection layer having a performance of canceling reflected light by utilizing the light interference action by the layer interface. Thereby, the image projected from the projector can be clearly seen. As the antireflection layer, for example, a single layer provided with a highly transparent low refractive index layer such as silicon oxide or lithium fluoride so as to be an optical thin film having a quarter wavelength of the main wavelength, or such A material in which a high refractive index layer such as titanium oxide or zinc oxide is appropriately laminated on a low refractive index layer can be used.

  Furthermore, in the present invention, a known hard coat layer, protective film layer, diffusion preventing layer or antistatic layer for increasing the strength of the screen can be provided on the surface of the light diffusion layer.

  In the present invention, it is also possible to provide a generally used magnetic layer in addition to the adhesive layer on the opposite surface of the light diffusion layer. It is also possible to use roll screens with electric and manual winding mechanisms.

  The reflective screen of the present invention projects the image of the projector from the light diffusion layer side and visually recognizes it from the light diffusion layer side.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, the content of this invention is not restricted to an Example. In addition, a part represents the mass part of solid content or a substantial component.

Example 1
<Production of base material>
A 1: 1 mixture of hardwood bleached kraft pulp (LBKP) and hardwood bleached sulfite pulp (LBSP) was beaten to 300 ml with Canadian Standard Freeness to prepare a pulp slurry. The sizing agent and alkyl ketene dimer were 0.5% by mass of pulp, 1% by mass of polyacrylamide as a strengthening agent, 1% by mass of cationized starch, 2% by mass of pulp, and polyamide epichlorohydrin resin by 0.1% of pulp. 5% by mass was added and diluted with water to give a 0.2% by mass slurry. This slurry was made with a long paper machine so as to have a basis weight of 110 g / m ² , dried and conditioned to obtain a substrate having a thickness of 115 μm. A polyethylene resin composition in which 10% by mass of anatase-type titanium dioxide is uniformly dispersed is melted at 320 ° C. with respect to a low-density polyethylene resin having a density of 0.918 g / cm ^{3 on} a paper-made base material to a thickness of 20 μm. The synthetic resin layer was provided while being cooled with a cooling roll that had been extruded and finely roughened.

The synthetic resin layer was subjected to a high-frequency corona discharge treatment, and then an easy-adhesion layer having the following composition was applied and dried so that gelatin was 50 mg / m ² .

<Easily adhesive layer>
Lime-processed gelatin 100 parts Sulfosuccinic acid 2-ethylhexyl ester salt 2 parts Chrome alum 10 parts

The light diffusion layer coating solution 1 having the following composition is applied to the synthetic resin layer provided on the substrate using a slide bead coating device so that the solid content coating amount is 20.0 g / m ² , and 10 ° C. And a 50 degreeC hot air was blown in order, and it dried and provided the light-diffusion layer, and produced the reflection type screen of Example 1. FIG. The aggregated particle-dispersible light diffusing fine particles were used by being previously dispersed with a homomixer using water as a dispersion medium. Moreover, when the void volume was measured using a mercury porosimeter (measuring instrument name: Autopore II 9220, manufacturer micromeritics instrument corporation), the thickness was 19.2 ml / m ² , and the thickness of the light diffusion layer was 34 μm as measured by an electron microscope. The void ratio was 55%.

<Preparation of silica dispersion>
After adding 4 parts of dimethyldiallylammonium chloride homopolymer (molecular weight 9,000) and 100 parts of vapor phase process silica (average primary particle diameter 7 nm, specific surface area 300 m ² / g) to water to prepare a preliminary dispersion, a high pressure homogenizer To prepare a silica dispersion having a solid concentration of 20%. The average secondary particle diameter was 80 nm when measured using LA910 manufactured by HORIBA, Ltd.

<Light diffusion layer coating solution 1>
Silica dispersion (as silica solid content) 150 parts Polyvinyl alcohol 100 parts (saponification degree 88%, average polymerization degree 3500)
Boric acid 16 parts Nonionic surfactant 0.3 parts (Polyoxyethylene alkyl ether)
Aggregated particle-dispersible light diffusing fine particles 150 parts (P-78A: manufactured by Mizusawa Chemical Industry Co., Ltd., average secondary particle size 6.0 μm, specific surface area 360 m ² / g, refractive index 1.45)
Single particle dispersible light diffusing fine particles 12 parts (Opto beads 500S: manufactured by Nissan Chemical Industries, silica, melamine resin composite fine particles (mainly melamine resin), average primary particle size 0.5 μm, true specific gravity 2.2 , Refractive index 1.65)
The total solid content concentration was adjusted with water so as to be 10%.

(Example 2)
A reflective screen of Example 2 was produced in the same manner as in Example 1 except that the polyethylene resin composition was extruded so that the thickness of the synthetic resin layer of Example 1 was 46 μm.

(Example 3)
As a base material, an aqueous slurry consisting of 100 parts of polyethylene terephthalate fibers having an average fiber diameter of 4 μm and an average fiber length of 10 mm and 150 parts of heat-sealing fibers (Melty 3380, manufactured by Unitika, melting point 130 ° C.) is prepared, and a wet papermaking method is used. A nonwoven fabric having a basis weight of 100 g / m ² and a thickness of 110 μm was prepared. As a synthetic resin layer, on one side of a polyethylene terephthalate film having a thickness of 23 μm, after applying and drying an acrylic adhesive so that the solid content is 10 g / m ² , the adhesive surface is pressure-bonded to the non-woven fabric, and then the synthetic resin The layer was provided on the nonwoven fabric as the substrate.

  After subjecting the synthetic resin layer to high-frequency corona discharge treatment, an easy-adhesion layer is provided in the same manner as in Example 1, and then a light diffusion layer is applied on the synthetic resin layer in the same manner as in Example 1. Thus, a reflective screen of Example 3 was produced.

(Comparative Example 1)
In the production of the reflective screen of Example 1, a reflective screen of Comparative Example 1 was produced in the same manner as in Example 1 except that the light diffusing layer was provided directly on the paper substrate without providing the synthetic resin layer. .

(Comparative Example 2)
A reflective screen of Comparative Example 2 was produced in the same manner as in Example 1 except that the thickness of the synthetic resin layer of Example 1 was 53 μm.

(Comparative Example 3)
The reflective screen of Comparative Example 3 was prepared in the same manner as in Example 1 except that the synthetic resin layer was not provided and the paper substrate was changed to a white polyethylene terephthalate film having a thickness of 150 μm in the production of the reflective screen of Example 1. Was made.

(Comparative Example 4)
Except that the light diffusion layer coating solution 1 of Example 1 was changed to the following light diffusion layer coating solution 2 and applied and dried so that the solid content coating amount was 13.0 g / m ^2. A reflective screen of Comparative Example 4 was produced. The porosity of the light diffusion layer measured in the same manner as in Example 1 was 3%.

<Light diffusion layer coating solution 2>
Alkali-treated gelatin 100 parts Nonionic surfactant 0.3 parts (polyoxyethylene alkyl ether)
150 parts of gel method silica (P-78A: manufactured by Mizusawa Chemical Co., Ltd., average secondary particle size 6.0 μm, specific surface area 360 m ² / g, refractive index 1.45)
The total solid content concentration was adjusted with water so as to be 10%.

(Comparative Example 5)
The paper base material of Example 1 was used as the reflective screen of Comparative Example 5 as it was.

  Regarding the obtained reflective screens of Examples 1 to 3 and Comparative Examples 1 to 5, the surface opposite to the light diffusion layer was pasted with a cellophane tape with the surface opposite to the whiteboard side, and a short focus projector (MP515ST, BenQ Japan Co., Ltd.) A 60-inch image with a 4: 3 aspect ratio was projected from the light diffusion layer side and observed from the projector side, and the texture of the image, the brightness of the image, and the viewing angle of the image were evaluated as follows. . These results are shown in Table 1.

<Film texture>
Images of women and cats in Japanese clothes were projected, and the quality of the images was visually evaluated according to the following criteria.
○: A soft and calm image that matches the image.
Δ: Image texture is slightly inferior to the above level.
X: The texture of the image is remarkably inferior to the above level.

<Brightness of image>
A white image was projected and the luminance was visually evaluated according to the following criteria.
○: The brightness of the image is high and good.
(Triangle | delta): The brightness | luminance of a video is a little inferior to the said (circle) level.
X: The brightness of the image is remarkably inferior to the above-mentioned ○ level.

<Viewing angle of video>
A white image was projected, the observation position was moved in the horizontal direction, and the viewing angle of the image was visually evaluated according to the following criteria.
○: The viewing angle of the image is good without any significant change in the brightness of the image at any observation position in the horizontal direction.
(Triangle | delta): The brightness | luminance of an image | video is a little inferior to the said (circle) level with a high viewing angle (position close | similar to the extended surface of a screen surface).
X: The luminance of the image is remarkably inferior to the above ○ level at a high viewing angle (position close to the extended surface of the screen surface).

From the results in Table 1, it can be seen that the reflective screen of the present invention can provide a soft and calm video image, and can provide a reflective screen with high brightness and wide viewing angle.
On the other hand, since the reflective screen of Comparative Example 1 was not provided with the synthetic resin layer, when the light diffusion layer was applied, the paper fiber as the base material was expanded and contracted, resulting in very large undulations. However, the texture of the image was extremely inferior. In the reflective screen of Comparative Example 2, the texture of the image was slightly inferior because the thickness of the synthetic resin layer exceeded 50 μm. Since the reflective screen of Comparative Example 3 did not use paper or non-woven fabric as a base material, the texture of the image was remarkably inferior. Since the reflective screen of Comparative Example 4 did not contain xerogel in the light diffusion layer, the luminance and viewing angle of the image were slightly inferior. Moreover, sufficient texture was not obtained. Since the reflective screen of Comparative Example 5 did not have a light diffusing layer, the image brightness and viewing angle were significantly inferior.

DESCRIPTION OF SYMBOLS 1 Base material 2 Synthetic resin layer 3 Light diffusing fine particle 4 Xerogel 5 Light diffusing layer 10 Reflective screen

Claims (1)

  A light diffusion layer comprising a paper or a nonwoven fabric as a base material, a synthetic resin layer having a thickness of 50 μm or less on at least one surface of the base material, and containing light diffusing fine particles and xerogel on the synthetic resin layer A reflective screen characterized by comprising: