JP7051353B2 - Transmissive screen - Google Patents

Description

The present invention relates to a transmissive screen suitable for window display applications.

Currently, the so-called back-projection type transmissive screen, in which the image projected from the projector is visually recognized from the opposite side of the projector across the screen, is becoming widespread in place of the conventional advertising media such as posters, signs, and signboards. be. In recent years, transmissive screens have attracted a great deal of attention as digital signage that can project digital content that does not require replacement, can be changed immediately, and requires dynamic posting as well as static display on a large screen. There is.

Most of the shop windows and the like face the road through which customers pass, and if the windows can be replaced with digital signage used as a large screen, it is very useful as an advertising medium. For this reason, there is an increasing need for a transmissive screen that is suitable for so-called window display applications, which is a show window sticking type.

Such a transmissive screen is usually adhesively processed so that it can be attached to a window. The adhesive processing is performed by providing an adhesive layer on the light diffusing layer side of the transmissive screen, or by providing an adhesive layer on the surface opposite to the surface on which the light diffusing layer is provided. Before the screen construction to which the transmissive screen is attached, the pressure-sensitive adhesive layer is protected by a separate base material, and the separate base material is peeled off at the time of screen construction to expose and attach the pressure-sensitive adhesive layer.

In a transmissive screen for a window display, high visibility is required so that an image projected from a projector can be visually recognized from a wide angle in order to maximize the function as an advertisement. As a transmissive screen satisfying such a requirement, a transmissive screen having a light diffusing layer containing light diffusing fine particles and xerogel on a light transmissive support (for example, Patent Documents 1 and 2) is known. Further, the transmissive screen is a transmissive screen that can be easily water-attached to a substrate to be adhered such as a glass or a plastic plate, and contains light diffusing fine particles and xerogel on at least one surface of the light transmissive support. A transmissive screen laminate (for example, Patent Document 3) having a light diffusing layer and sequentially laminating an adhesive layer A, an intermediate base material, and an adhesive layer B on the light diffusing layer is known.

However, the transmissive screen having a light diffusion layer containing these xerogels is a conventionally known transmissive screen, for example, a transparent resin binder having an average particle size of 1.0 to 10 μm and having an average particle size of 1.0 to 10 μm with respect to the refractive index of the transparent resin binder. It contains a transmissive screen (for example, Patent Document 4) having a light scattering layer containing spherical fine particles having a relative refractive index n of 0.91 <n <1.09 (where n ≠ 1), and light transmissive beads. A screen having a light scattering layer (for example, Patent Document 5), a transmissive screen having a light diffusing layer containing porous particles (for example, Patent Document 6), a light diffusing fine particle and a resin binder, and the light diffusing fine particles. Compared to a transmissive screen (for example, Patent Document 7) in which a part of the light is projected from the light diffusion layer, the viewing angle at the time of projecting by the projector is wider, and the visibility of the image from the projector side is also good, but from the outside. Because the light diffusion layer containing xerogel is easily deformed due to the mechanical elements of, the projected image is partially distorted after screen construction, and when used for a roll-up roll screen, it may be rubbed or stepped at the beginning of winding. Similarly, partial distortion of the projected image may occur. In addition, there is a problem that cleaning work becomes difficult when the surface of the light diffusion layer becomes dirty.

International Publication No. 2013/129290 Pamphlet Japanese Unexamined Patent Publication No. 2013-195548 Japanese Unexamined Patent Publication No. 2014-137539 Japanese Unexamined Patent Publication No. 2001-242546 International Publication No. 99/050710 Pamphlet Japanese Unexamined Patent Publication No. 2006-119318 Japanese Unexamined Patent Publication No. 2005-024942

An object of the present invention is to provide a transmissive screen having a wide viewing angle of an image projected from a projector, improved partial distortion of the projected image, and good cleanability.

The above-mentioned problems are achieved by the following inventions.
(1) A transmissive screen having a light -diffusing layer containing light-diffusing fine particles and xerogel, a pressure-sensitive adhesive layer, and a light-transmitting base material on at least one surface of the light-transmitting support in this order. The diffused fine particles are single particle-dispersible light-diffusing fine particles having an average primary particle diameter of 0.10 μm or more and 200 μm or less, and aggregated particle-dispersible light diffusion having an average secondary particle diameter of more than 1.0 μm and an upper limit of 200 μm. The xerogels are fine particles, the xerogel is composed of inorganic fine particles and a resin binder, and the inorganic fine particles are at least one selected from amorphous synthetic silica, alumina, and alumina hydrate, and the resin binder is a complete or partial Ken. It is a polyvinyl alcohol, the content of the resin binder is 5 to 70% by mass with respect to the inorganic fine particles, the dry solid content coating amount of the light diffusion layer is 5 to 30 g / m ² , and the adhesion. A transmissive screen characterized in that the agent layer contains an acrylic pressure-sensitive adhesive, the solid content of the pressure-sensitive adhesive layer is 18 to 50 g / m ² , and the thickness of the light-transmitting base material is 12 to 50 μm. ..

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a transmissive screen having a wide viewing angle of an image projected from a projector, improved partial distortion of the projected image, and good cleanability.

Schematic cross-sectional view showing an embodiment of the transmissive screen of the present invention. Schematic cross-sectional view showing another embodiment of the transmissive screen of the present invention. Schematic cross-sectional view showing a laminated body including the transmissive screen of the present invention and a state of bonding using the laminated body. Another schematic cross-sectional view showing another laminated body including the transmissive screen of the present invention and a state of bonding using the same. Schematic cross-sectional view showing still another laminated body including the transmissive screen of the present invention and a state of bonding using the same.

The present invention will be described in detail below.
FIG. 1 is a schematic cross-sectional view showing an embodiment of a transmissive screen of the present invention. In FIG. 1, the transmissive screen 1 has a light diffusing layer 3 containing light diffusing fine particles 2 and xerogel 5 on one surface of a light transmissive support 4, and a pressure-sensitive adhesive layer 6A is provided on the light diffusing layer 3. And the light-transmitting base material 7 in this order. The light-transmitting base material 7 is fixed by the pressure-sensitive adhesive layer 6A so as not to be peeled off from the light-diffusing layer 3.

FIG. 2 is a schematic cross-sectional view showing another embodiment of the transmissive screen of the present invention. In FIG. 2, the transmissive screen 1 has a light diffusing layer 3 containing light diffusing fine particles 2 and xerogel 5 on both sides of the light transmissive support 4, and a pressure-sensitive adhesive layer 6A is provided on each of the light diffusing layers 3. It has a light-transmitting base material 7. Also in the transmissive screen of FIG. 2, the light transmissive base material 7 is fixed by the pressure-sensitive adhesive layer 6A so as not to be peeled off from the light diffusing layer 3.

FIG. 3 is a schematic cross-sectional view showing a laminated body including the transmissive screen of the present invention and a state in which the laminated body is bonded using the laminated body. The transmissive screen is generally attached to a substrate to be adhered such as glass or a plastic plate by water-adhesion. In FIG. 3, the transmissive screen laminate 100 before water-adhesion and the transmissive screen laminate 100 to be adhered using the same are used. The state after water-pasting that the transmissive screen 1 was bonded on the base material 10 was shown. The transmissive screen laminate 100 before water application has the light diffusing layer 3, the pressure-sensitive adhesive layer 6A, and the light transmissive on one surface of the light transmissive support 4, from the side closer to the light transmissive support 4. The base material 7 is provided in this order, the pressure-sensitive adhesive layer 6B is provided on the other surface of the light-transmitting support 4, and the separate base material is placed on the pressure-sensitive adhesive layer 6B (lower in the figure). 8 is provided. The light-transmitting base material 7 is fixed by the pressure-sensitive adhesive layer 6A so as not to be peeled off from the light-diffusing layer 3. When the transmissive screen laminate 100 is attached to a base material 10 to be adhered such as glass, the separate base material 8 is peeled off to expose the pressure-sensitive adhesive layer 6B, and a means such as spraying is applied onto the pressure-sensitive adhesive layer 6B. Sufficient water is also applied to the surface of the adhesive base material 10 to which the transmissive screen is attached by means such as spraying, and the adhesive base material 10 and the pressure-sensitive adhesive layer 6B are also applied. The water-applied surfaces of the above are overlapped with each other, and then the surface of the light-transmitting base material 7 is rubbed from the center to the outside by using a scraping means such as a blade to scrape the water. Paste is done. The figure on the right side (after watering) of FIG. 3 shows the state after this watering.

FIG. 4 is a schematic cross-sectional view showing a state in which the laminated body including the transmissive screen of the present invention is bonded to another laminated body using the same. FIG. 4 also shows the state after water-pasting the transmissive screen laminate 100 before water-pasting and the transmissive screen 1 bonded to the adhered base material 10 using the transparent screen laminate 100. In the transmissive screen laminate 100 before water application, the light diffusing layer 3, the pressure-sensitive adhesive layer 6A, and the light transmissive base material are placed on one surface of the light transmissive support 4 from the side closest to the light transmissive support 4. 7 is provided in this order, and on the other surface of the light-transmitting support 4, the light-diffusing layer 3 and the pressure-sensitive adhesive layer are placed on the light-transmitting support 4 from the side closest to the light-transmitting support 4. It has 6B, and a separate base material 8 is provided on the pressure-sensitive adhesive layer 6B (lower side in the figure). The light-transmitting base material 7 described above is fixed by the pressure-sensitive adhesive layer 6A so as not to be peeled off from the light-diffusing layer 3. When the transmissive screen laminate 100 is attached to the substrate to be adhered, the separate substrate 8 is peeled off in the same manner as in FIG. 3, and the surface having the substrate 10 to be adhered and the pressure-sensitive adhesive layer 6B is overlapped. At the same time, water is applied. The figure on the right side (after watering) of FIG. 4 shows the state after this watering.

FIG. 5 is a schematic cross-sectional view showing still another laminated body including the transmissive screen of the present invention and a state in which the laminated body is bonded using the same. Also in FIG. 5, the state of the transmissive screen laminate 100 before water-adhesion and the transmissive screen 1 after adhering the transmissive screen 1 on the adhered base material 10 using the transparent screen laminate 100 is shown. In the transmissive screen laminate 100 before water application, the light diffusing layer 3, the pressure-sensitive adhesive layer 6A, and the light transmissive base material are placed on one surface of the light transmissive support 4 from the side closest to the light transmissive support 4. 7 is provided in this order, and on the other surface of the light-transmitting support 4, a light-diffusing layer is placed on the light-transmitting support 4 (lower in the figure) from the side closer to the light-transmitting support 4. 3. The pressure-sensitive adhesive layer 6B, the intermediate base material 9, and the pressure-sensitive adhesive layer 6C are provided in this order, and a separate base material 8 is provided on the pressure-sensitive adhesive layer 6C (lower in the figure). The light-transmitting base material 7 is fixed by the pressure-sensitive adhesive layer 6A so as not to be peeled off from the light-diffusing layer 3. Further, the intermediate base material 9 is also fixed by the pressure-sensitive adhesive layer 6B so as not to be peeled off from the light diffusion layer 3.

When the transmissive screen laminate 100 is attached to the substrate to be adhered, the separate substrate 8 of the transmissive screen laminate 100 is peeled off, and the surface having the substrate 10 to be adhered and the pressure-sensitive adhesive layer 6C. Is overlapped and watered. The figure on the right side (after watering) of FIG. 5 shows the state after this watering. In the transmissive screen 1 attached to the adhered substrate in this way, the light diffusion layer 3 is not attached to the adhered substrate 10 via the adhesive layer 6B, and the adhesive layer 6B is further intermediate. It is attached onto the adhered substrate 10 via the substrate 9 and the pressure-sensitive adhesive layer 6C. As described in Patent Document 3 described above, the transmissive screen 1 attached with such a configuration is a group to be adhered, for example, when the transmissive screen becomes unnecessary and is peeled off from the substrate to be adhered. It is preferable because it can be peeled off without leaving the pressure-sensitive adhesive layer 6B and the light diffusion layer 3 on the material 10.

As described above, the water application is performed by rubbing the surface of the light transmissive base material 7 with a scraping means such as a blade. As will be described later, a transmissive screen having a light diffusing layer containing light diffusing fine particles and xerogel has an excellent characteristic that the viewing angle of the image projected from the projector is wide, but the light diffusing layer containing xerogel has an excellent property. It was fragile, and external mechanical elements such as blades could cause partial distortion of the projected image. Even in a transmissive screen that is not attached to the substrate to be adhered, for example, when it is used for a roll-up roll screen, partial distortion of the projected image is similarly caused by the rubbing of the transmissive screen and the step at the beginning of winding. It could occur. The present invention solves such a problem by setting the solid content of the pressure-sensitive adhesive layer when adhering the light-transmitting base material to the light-diffusing layer to 18 g / m ² or more and the thickness of the light-transmitting base material to 12 μm or more. By doing so, it will be solved. Further, the light diffusing layer containing the xerogel was easy for water to permeate and dirt easily entered into the xerogel, and it was difficult to clean. However, the adhesive layer and the light transmissive substrate were placed on the light diffusing layer in this order. Even if the surface on the side having the light diffusion layer becomes dirty, the dirt is present on the light-transmitting substrate, so that cleaning is easy.

The "transmissive type" of the transmissive screen of the present invention, which is attached using the transmissive screen laminate described above, means a screen having a total light transmittance of more than 50% as defined by JIS-K7105. .. In the present invention, the total light transmittance of the transmissive screen includes the pressure-sensitive adhesive layer exposed after the separate base material is peeled off from the laminated body.

The light diffusing layer included in the transmissive screen in the present invention contains light diffusing fine particles and xerogel.

Usually, when the light diffusing fine particles are applied to the light transmitting support, a resin binder for binding the light diffusing fine particles is required. The coating liquid containing the light-diffusing fine particles and the resin binder is diluted with an organic solvent or water for the purpose of adjusting the viscosity to ensure the coatability, and is applied to a light-transmitting support, dried, or a photocurable resin. Or, an electron beam curing resin is generally applied as a resin binder without a solvent. In the light diffusing layer coated by such a method, the refractive index of both the resin binder and the light diffusing fine particles is generally around 1.50, so that the relative refractive index of the light diffusing fine particles with respect to the resin binder is low. Efficient light diffusion is unlikely to occur. On the other hand, in the present invention, by supporting the light diffusing fine particles on the xerogel, voids of the xerogel (air having a refractive index of 1.0) exist on the surface of the light diffusing fine particles, and the relative refractive index of the light diffusing fine particles with respect to the air. Is very high, so that the light diffusing fine particles can be efficiently diffused, and a transmissive screen having a wide viewing angle can be provided for the image projected from the projector.

In addition, the above-mentioned Patent Documents 4 and 5 describe the light diffusing layer in which the light diffusing fine particles are held by the resin binder, and the light diffusing layer of the present invention in which the light diffusing fine particles are carried on the xerogel is essentially. Is different.

The light-diffusing fine particles contained in the light-diffusing layer in the present invention can be used regardless of whether they are organic fine particles or inorganic fine particles as long as they have the ability to diffuse light, but a visual field in which an image projected from a projector can be visually recognized. Single particle dispersive light-diffusing fine particles with an average primary particle size of 0.10 μm or more, or agglomeration with an average secondary particle size of more than 1.0 μm from the viewpoint of very wide corners and improved visibility from both sides of the screen. It is preferable to use light-diffusing fine particles having a particle size (hereinafter, referred to as agglomerated particle-dispersible light-diffusing fine particles). The upper limit of the average primary particle size of the single-particle-dispersible light-diffusing fine particles is preferably 200 μm or less. Further, it is preferable that the upper limit of the average secondary particle diameter of the light diffusing fine particles having agglomerated particle dispersibility is 200 μm.

The average primary particle size referred to in the present invention can be measured by photography with a transmission electron microscope, but in the case of single particle dispersive light-diffusing fine particles, a laser scattering type particle size distribution meter (for example, Horiba Seisakusho) It can also be measured as a number median diameter using LA910) manufactured by LA 910). The average secondary particle diameter of the agglomerated particle-dispersible light-diffusing fine particles 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 light diffusivity of the light diffusing fine particles depends on the specific surface area in addition to the relative refractive index described above. Further, the specific surface area depends on the average primary particle size of the light diffusing fine particles, and in the case of single particle dispersible fine particles, it can be easily calculated from the average primary particle size and the specific gravity.

Further, the refractive index of the light diffusing fine particles is preferably 1.30 or more, but when it exceeds 1.55, a transmissive screen having a particularly wide viewing angle and excellent visibility from both sides of the screen can be obtained. be able to.

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, and ethylene-vinyl acetate-. Multiple copolymers such as acrylic, SBR, NBR, MBR, carboxylated SBR, carboxylated NBR, carboxylated MBR, polyvinyl chloride, polyvinylidene chloride, polyester, polyolefin, polyurethane, polymethacrylate, polytetrafluoroethylene, polymethacrylic It can be widely selected from conventionally known ones such as methyl acid, polycarbonate, polyvinyl acetal resin, rosin ester resin, episulfide resin, epoxy resin, silicone resin, silicone-acrylic resin, and melamine resin. Further, those 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 of such organic fine particles and a small amount of inorganic fine particles (the ratio of the inorganic fine particles is less than 50% by mass) are used, they 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.

Examples of the inorganic fine particles include silica, alumina, rutyl-type titanium dioxide, anatase-type titanium dioxide, zinc oxide, zinc sulfide, lead white, antimony oxide, zinc antimonate, lead titanate, potassium titanate, zirconium oxide, and cerium oxide. There are hafnium oxide, tantalum pentoxide, niobium pentoxide, yttrium oxide, chromium oxide, tin oxide, molybdenum oxide, ATO, ITO, and oxide glass such as silicate glass, phosphate glass, and borate glass. These composite oxides or composite sulfides can also be widely used. Further, in the case of inorganic fine particles having photocatalytic activity such as titanium oxide and zinc oxide, those having an extremely thin surface coated with silica, alumina, boron or the like can also be used. Further, even when composite particles of inorganic fine particles and a small amount of organic polymer (the ratio of organic fine particles is less than 50% by mass) are used, they can be substantially regarded as inorganic fine particles and used. Further, the inorganic fine particles used as the light diffusing fine particles are preferably single 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 individually or in combination of a plurality of types, or both the organic fine particles and the inorganic fine particles can be mixed and used. ..

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 diameter and the specific gravity. It is preferably 005 to 15.0 g / m ² , more preferably 0.01 to 12.0 g / m ² , and even more preferably 0.03 to 10.0 g / m ² .

Next, the xerogel contained in the light diffusion layer of the present invention will be described. The light diffusing layer of the present invention retains light diffusing fine particles by xerogel.

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

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

The xerogel of the present invention 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 decrease and sufficient transparency and brightness may not be obtained. Further, the inorganic fine particles constituting the xerogel of the present invention preferably have a secondary aggregated particle diameter of 500 nm or less on average. If the average secondary particle diameter exceeds 500 nm, the transparency of the light diffusion layer may decrease and sufficient transparency and brightness may not be obtained. In the case of inorganic fine particles having a secondary aggregate particle size, the average primary particle size referred to in the present invention can be measured by photography with a transmission electron microscope, and the average secondary particle size is a laser scattering type particle size. It can be measured as a number median diameter using a distribution meter (for example, LA910 manufactured by Horiba Seisakusho).

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. Amorphous synthetic particles can be obtained because a high void ratio can be obtained. Silica, alumina or alumina hydrate is preferred.

Amorphous synthetic silica can be roughly classified into wet method silica, vapor phase method silica, and others depending on the production method. Wet silica is further classified into precipitation silica, gel silica, and sol silica depending on the production method. Precipitation method Silica is produced by reacting sodium silicate and sulfuric acid under alkaline conditions, and the silica particles that have grown particles are aggregated and settled, and then commercialized through the steps of filtration, washing with water, drying, crushing and classification. As the sedimentation method silica, for example, it is commercially available from Tosoh Silica Co., Ltd. as Nipseal (registered trademark) and from Tokuyama Corporation as Tokuseal (registered trademark). Gel method Silica is produced by reacting sodium silicate and sulfuric acid under acidic conditions. During aging, the fine particles dissolve and reprecipitate to bond other primary particles to each other, so that the distinct primary particles disappear and form relatively hard aggregated particles with an internal void structure. For example, it is marketed as Nipgel (registered trademark) by Tosoh Silica Co., Ltd. and as siloid and silojet by Grace Japan Co., Ltd. Sol method silica, also called colloidal silica, is obtained by heat-aging silica sol obtained through compound decomposition with acid of sodium silicate or through an ion exchange resin layer. For example, Snowtex (registered trademark) from Nissan Chemical Industry Co., Ltd. It is commercially available as.

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

Gas phase silica can be preferably used in the present invention. 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 transparency, the average primary particle diameter is 3 to 15 nm and the average aggregated particle diameter is 5 to 50 μm. Moreover, the one having a specific surface area of 200 m ² / g or more by the BET method is used. The average primary particle diameter referred to in the present invention is the average particle diameter obtained by using the diameter of a circle equal to the projected area of each of the 100 primary particles existing in a certain area as the particle diameter by observing the fine particles with an electron microscope. The BET method in the present invention is one of the methods for measuring the surface area of powder by the vapor phase adsorption method, and is a method for obtaining the total surface area of 1 g of a sample from the adsorption isotherm, that is, the specific surface area. Normally, nitrogen gas is often used as the adsorbed gas, and the method of measuring the adsorbed amount from the pressure or volume change of the adsorbed gas is most often used. The most prominent representation of the isotherms of multimolecular adsorption is the Brunauer, Emmett, and Teller equations, called the BET equations, which are widely used to determine surface area. The adsorption amount is obtained based on the BET formula, and the surface area is obtained by multiplying the area occupied by one adsorbed molecule on the surface.

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

In the present invention, wet method silica obtained by pulverizing an average secondary particle diameter 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 silica particles used in the present invention are preferably wet silica particles having an average primary particle diameter of 18 nm or less and an average aggregated particle diameter of 5 to 50 μm, which are finely ground in the presence of a cationic compound. It is preferable to use the wet method 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 δ group crystals are particularly preferable. Although γ-alumina can reduce the size of primary particles to about 10 nm, it is usually possible to reduce the size of secondary particle crystals from several thousand to tens of thousands nm by ultrasonic waves, high-pressure homogenizers, counter-collision jet crushers, etc. on average. A particle having a particle size of 500 nm or less, preferably pulverized to about 20 to 300 nm can be used.

The alumina hydrate of the present invention is represented by the constitutive equation of Al ₂ O ₃ · nH ₂ O (n = 1 to 3). 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, and hydrolysis of aluminate.

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

It is also possible to use two or more kinds of inorganic fine particles together from the above-mentioned inorganic fine particles. For example, the combined use of pulverized wet silica and vapor phase silica, the combined use of finely pulverized wet silica with alumina or alumina hydrate, and the combined use of vapor phase silica with alumina or alumina hydrate can be mentioned. .. The ratio in the case of this combined use is preferably in the range of 7: 3 to 3: 7 in any mode.

In the present invention, the resin binder used together with the inorganic fine particles constituting the xerogel is not particularly limited, but a highly transparent hydrophilic resin binder is preferably used. For example, polyvinyl alcohol, gelatin, polyethylene oxide, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, polyurethane, dextran, dextrin, carrageenan (κ, ι, λ, etc.), agar, pullulan, water-soluble polyvinyl butyral, hydroxyethyl cellulose, carboxylmethylcellulose. And so on. Two or more of these hydrophilic resin binders can be used in combination. Preferred hydrophilic resin binders are fully or partially saponified polyvinyl alcohol and cationically 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. .. This makes it possible to obtain a high viewing angle of the image. Further, the above-mentioned light diffusing fine particles are preferably 0.1 to 200% by mass, particularly preferably 0.3 to 150% by mass, based on the inorganic fine particles constituting the xerogel.

For the light diffusion layer, a dural agent may be used together with the resin binder, if necessary. Specific examples of the hard film agent include aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and chlorpentandione, bis (2-chloroethyl) urea, and 2-hydroxy-4,6-dichloro-1. , 3,5-Triazine, compounds having reactive halogens as described in US Pat. No. 3,288,775, divinyl sulfone, compounds having reactive olefins as described in US Pat. No. 3,635,718, N-methylol compounds as described in US Pat. No. 2,732,316, isocyanatos 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 611, carbodiimide compounds as described in US Pat. No. 3,100,704, epoxy compounds as described in US Pat. No. 3,091,537, halogen carboxylaldehydes such as mucochloric acid, There are dioxane derivatives such as dihydroxydioxane, inorganic cross-linking agents such as chromium lightning, zirconium sulfate, borosand, boric acid, borates and the like, and these can be used alone or in combination of two or more.

The amount of the dry solid content applied to the light diffusion layer is preferably in the range of 1 to 50 g / m ² , more preferably in the range of 3 to 40 g / m ² , and particularly preferably in the range of 5 to 30 g / m ² . Further, the light diffusion layer includes a cationic polymer, an antiseptic, a surfactant, a coloring dye, a coloring pigment, an ultraviolet absorber, an antioxidant, a pigment dispersant, a defoaming agent, a leveling agent, an optical brightener, and a viscosity. Stabilizers, pH adjusters and the like can also be added.

The light diffusing layer may be composed of two or more layers, and in this case, the composition of the light diffusing layers may be the same as or different from each other. When there are a plurality of light diffusing layers, the light diffusing fine particles can be contained in at least one light diffusing 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 method, a slide curtain method, an extrusion method, 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 light-transmitting support, the light-transmitting base material, and the intermediate base material used as necessary in the transmissive screen of the present invention are not particularly limited as long as they have light-transmitting properties, such as glass and the like. A plate-shaped one made of plastic, a film-shaped one, or the like can be used. The type of glass is not particularly limited, but in general, oxide glass such as silicate glass, phosphate glass, and borate glass is practical, and in particular, silicate glass and alkali silicate glass are practical. , Soda lime glass, potash lime glass, lead glass, barium glass, borosilicate glass and the like silicate glass are preferable. As the plastic, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polypropylene, polyethylene, polyarylate, acrylic, acetyl cellulose, polyvinyl chloride and the like can be used. , It is preferable because the mechanical strength is improved. The haze value of the light-transmitting support, the light-transmitting base material, and the intermediate base material used as needed is preferably 30% or less.

The thickness of the light-transmitting support of the present invention can be appropriately selected depending on the material to be applied, but is generally about 10 μm to 30 mm, preferably about 20 μm to 20 mm.

The thickness of the light-transmitting substrate in the present invention is 12 μm or more, preferably 12 to 50 μm. If it is less than 12 μm, partial distortion of the projected image occurs in the transmissive screen or the roll screen after water application as described above. If it exceeds 50 μm, the rigidity of the transmissive screen becomes too high, which is not preferable.

The light-transmitting substrate in the present invention is preferably coated on the light-transmitting substrate with an adhesive, dried, and then bonded to the surface of the light-diffusing layer because the adhesiveness of the light-transmitting substrate is good. When the pressure-sensitive adhesive is applied on the light-diffusing layer and dried, the pressure-sensitive adhesive may partially penetrate into the light-diffusing layer and the adhesiveness may not be obtained.

As the pressure-sensitive adhesive for bonding the light-transmitting base material and the separate base material in the present invention, commonly used synthetic resin-based pressure-sensitive adhesives such as acrylic, silicone-based, urethane-based, and rubber-based adhesives can be used.

The coating amount of the pressure-sensitive adhesive layer to which the light-transmitting substrate is bonded in the present invention is 18 g / m ² or more, preferably 18 to 50 g / m ² . If it is less than 18 g / m ² , not only the adhesiveness of the light-transmitting substrate is poor, but also partial distortion of the projected image occurs in the transmissive screen or the roll screen after water application. If it exceeds 50 g / m ² , the rigidity of the transmissive screen becomes too high, which is not preferable.

As the coating method used for coating these pressure-sensitive adhesives 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 adhesive layer B may be provided with an extra-fine groove by embossing so that air can easily escape when the transmissive screen is attached to the substrate to be adhered.

In the present invention, a protective base material may be further provided on the light-transmitting base material for the purpose of further protecting the surface of the light-transmitting base material. As the protective base material, a known base material such as a film or paper having a pressure-sensitive adhesive layer adjusted so that the pressure-sensitive adhesive does not remain on the light-transmitting base material side when peeled off can be used. Since it is finally peeled off and used, there are no particular restrictions on the thickness and haze value, but from the viewpoint of handling, the thickness is preferably 1.0 to 100 μm, more preferably 5.0 to 50 μm.

Further, the surface of the light-transmitting support may be subjected to an easy-adhesion treatment for the purpose of improving the adhesiveness between the light-diffusing layer and the light-transmitting support, or a separate easy-adhesive layer may be provided. ..

The transmissive screen of the present invention may have a known light antireflection layer having a performance of canceling reflected light by utilizing the interference action of light by the layer interface on the surface of the light transmissive base material. This makes it possible to clearly see the image projected from the projector. As the antireflection layer, for example, a single layer in which a highly transparent low refractive index layer such as silicon oxide or lithium fluoride is provided so as to be an optical thin film having a main wavelength of 1/4, or such a single layer. A low refractive index layer on which a high refractive index layer such as titanium oxide or zinc oxide is appropriately laminated can be used. Furthermore, it is also possible to prevent light reflection by creating physical irregularities on the surface of the light-transmitting substrate.

Further, it is also possible to provide a known hard coat layer, a light diffusion prevention layer and an antistatic layer for increasing the strength of the screen on the surface of the light transmissive base material.

The transmissive screen of the present invention preferably projects the image of the projector from the light-transmitting base material side (the side that is not in contact with the adhered base material), but projects from the opposite side (the adhered base material side). It is also possible to use it.

Hereinafter, the present invention will be described in detail with reference to Examples, but the content of the present invention is not limited to the Examples. In addition, a part represents a mass part of a solid content or a substantial component.

(Example 1)
A slide bead of a light diffusion layer coating liquid 1 having the following composition on one side of a transparent polyethylene terephthalate film (haze value 4%) having a thickness of 100 μm as a light transmissive support so that the solid content becomes 20.0 g / m ² . The film was applied using a coating device, and hot air at 10 ° C. and 50 ° C. was sequentially blown to dry the film to provide a light diffusion layer. The agglomerated particle-dispersible light-diffusing fine particles were used by pre-dispersing them with a homomixer using water as a dispersion medium. In addition, the void volume was measured using a mercury porosity meter (measuring instrument name Autopore II 9220 manufacturer micromeritics instrument corporation) and found to be 19.2 ml / m ² , and the thickness of the cross section of the light diffusion layer was 34 μm as observed by an electron microscope. The porosity was 55%.

<Preparation of silica dispersion>
A pre-dispersion solution was prepared by adding 4 parts of dimethyldiallyl ammonium chloride homopolymer (molecular weight 9,000) and 100 parts of vapor phase silica (average primary particle diameter 7 nm, specific surface area 300 m ² / g) to water, and then a high-pressure homogenizer. To produce a silica dispersion having a solid content concentration of 20%. The average secondary particle diameter was 80 nm as measured using LA910 manufactured by HORIBA, Ltd.

<Light diffusion layer coating liquid 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)
Agglomerated particles Dispersible light-diffusing fine particles 150 parts (P-78A: manufactured by Mizusawa Industrial Chemicals, Inc., average secondary particle diameter 6.0 μm, specific surface area 360 m ² / g, refractive index 1.45)
12 parts of single particle dispersible light diffusing fine particles (Optobeads 500S: manufactured by Nissan Chemical Industry Co., Ltd., silica, melamine resin composite fine particles (mainly melamine resin), average primary particle diameter 0.5 μm, true specific gravity 2.2, Refractive index 1.65)
It was adjusted with water so that the total solid content concentration was 10%.

Subsequently, the following adhesive layer liquid A is applied and dried on one side of a transparent polyethylene terephthalate film (haze value 3%) having a thickness of 35 μm as a light-transmitting substrate so that the solid content is 30 g / m ² . After forming the pressure-sensitive adhesive layer, the surface of the light-transmitting substrate having the pressure-sensitive adhesive layer was adhered to the surface of the light-diffusing layer provided on the light-transmitting support. Subsequently, the following pressure-sensitive adhesive layer liquid B was applied and dried on the other surface of the light-transmitting support so as to have a solid content of 10 g / m ² . A transparent polyethylene terephthalate film (haze value of 3%) having a thickness of 25 μm, which had been peeled off by silicone resin processing as a separate base material, was adhered to the B surface of the adhesive layer. Subsequently, after slitting to a width of 1524 mm, it was cut into a lithographic sheet having a length of 1 m, finished, and heated in an environment of 35 ° C. and 50% RH for 4 days to obtain a transmissive screen laminate. .. The total light transmittance of the transmissive screen of Example 1 in which the separate base material was peeled off from this transmissive screen laminate was 70%.

<Adhesive layer liquid A>
Acrylic copolymer resin 100 parts Cross-linking agent 4 parts (hexamethylene diisocyanate)
Toluene was adjusted so that the total solid content concentration was 30%.

<Adhesive layer liquid B>
Acrylic copolymer resin 100 parts Cross-linking agent 4 parts (hexamethylene diisocyanate)
UV absorber 2 parts (2-hydroxy-4-n-octylbenzophenone)
Toluene was adjusted so that the total solid content concentration was 30%.

(Example 2)
A transmissive screen laminate was obtained in the same manner as in Example 1 except that the light transmissive substrate of Example 1 was changed to a transparent polyethylene terephthalate film (haze 2%) having a thickness of 16 μm. The total light transmittance of the transmissive screen of Example 2 in which the separate base material was peeled off from this transmissive screen laminate was 71%.

(Example 3)
A transmissive screen laminate was produced in the same manner as in Example 1 except that it was applied and dried so that the solid content of the pressure-sensitive adhesive layer of Example 1 was 20 g / m ² . The total light transmittance of the transmissive screen of Example 3 in which the separate base material was peeled off from this transmissive screen laminate was 71%.

(Comparative Example 1)
The light diffusion layer coating liquid 1 of Example 1 was used as the following light diffusion layer coating liquid 2, and the light diffusion layer was provided by applying and drying using a slide bead coating device so that the solid content was 13 g / m ² . A transmissive screen laminate was produced in the same manner as in Example 1 except for the above. The total light transmittance of the transmissive screen of Comparative Example 1 in which the separate base material was peeled off from this transmissive screen laminate was 72%.

<Light diffusion layer coating liquid 2>
Alkaline-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 Industrial Chemicals, Inc., gel type silica particles, average secondary particle diameter 6.0 μm, specific surface area 360 m ² / g, refractive index 1.45)
12 parts of single particle dispersible light diffusing fine particles (Optobeads (registered trademark) 500S: manufactured by Nissan Chemical Industry Co., Ltd., silica, melamine resin composite fine particles (mainly melamine resin), average primary particle diameter 0.5 μm, true specific gravity 2.2, refractive index 1.65)
It was adjusted with water so that the total solid content concentration was 10%.

(Comparative Example 2)
In Example 1, a transmissive screen laminate was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive layer and the light-transmitting base material were not provided on the light-diffusing layer. The total light transmittance of the transmissive screen of Comparative Example 2 in which the separate base material was peeled off from this transmissive screen laminate was 72%.

(Comparative Example 3)
A transmissive screen laminate was obtained in the same manner as in Example 1 except that the light transmissive substrate of Example 1 was changed to a transparent polyethylene terephthalate film (haze 1.5%) having a thickness of 8 μm. The total light transmittance of the transmissive screen of Comparative Example 3 in which the separate base material was peeled off from this transmissive screen laminate was 72%.

(Comparative Example 4)
A transmissive screen laminate was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive layer A of Example 1 was applied and dried so that the solid content of the pressure-sensitive adhesive layer A was 15 g / m ² . The total light transmittance of the transmissive screen of Comparative Example 4 in which the separate base material was peeled off from this transmissive screen laminate was 71%.

The obtained transmissive screens of Examples 1 to 3 and Comparative Examples 1 to 4 were water-coated on a transparent acrylic plate surface having a thickness of 5 mm as a substrate to be adhered. Specifically, water containing a surfactant is sprayed on the surface of the pressure-sensitive adhesive layer exposed by peeling the separate base material from the obtained transmissive screen laminate and the surface of the transparent acrylic plate, respectively, and the surface of the pressure-sensitive adhesive layer and the transparent surface are transparent. After the surface of the acrylic plate is brought into close contact, water containing a surfactant is further sprayed on the outermost surface (light-transmitting base surface) of the transmissive screen to combine with the air existing between the adhesive layer and the transparent acrylic plate. Water containing a surfactant was scraped off from the light-transmitting substrate side with a rubber squeegee and both were attached. After that, the following evaluation was carried out.

<Viewing angle>
The transmissive screen attached to the transparent acrylic plate stands vertically, and the image is actually projected from the light diffusion layer side by a digital projector (MP515ST, made by BenQ), and projected onto the transmissive screen from the opposite side of the projector. I observed the video. The projector irradiates the vertical line of the screen at an angle of about 30 degrees from above. The image was visually observed by changing the viewing angle in the horizontal direction from 0 ° to 90 ° from the opposite side of the projector, and evaluated according to the following evaluation criteria.
◎: The image can be sufficiently confirmed at all angles and the viewing angle is very wide ○: It is slightly inferior to the above ◎, but the image can be confirmed at all angles and the viewing angle is wide △: The image at a high viewing angle around 90 ° It is a little difficult to check ×: It is difficult to check the image at a high viewing angle around 90 °

<Distortion of projected image>
A transmissive screen attached to a transparent acrylic plate is erected vertically, and a grid-like image is projected from the light diffusion layer side by a digital projector (MP515ST, manufactured by BenQ), and projected onto the transmissive screen from the opposite side of the projector. The grid-like image was observed and visually evaluated according to the following criteria.
⊚: There is no grid-like distortion.
◯: There is some grid-like distortion, but there is no problem.
Δ: A level at which grid-like distortion is seen and becomes a problem.
X: A level at which grid-like distortion is significantly observed and becomes a problem.

<Cleanability>
From the light diffusion layer side of the transmissive screen attached to the above-mentioned 5 mm thick transparent acrylic plate surface, draw a cross line with an oil-based marker, wipe it off with a waste cloth soaked in ethanol, and use the oil-based marker at that time. The remaining condition was visually evaluated according to the following criteria.
○: The line of the permanent marker has completely disappeared.
△: There is some residual oil-based marker line, but there is no problem.
×: The level at which the oil-based marker line remains clearly and becomes a problem.

From the results shown in Table 1, the transmissive screen of the present invention provides a transmissive screen having a wide viewing angle of the image projected from the projector, improved partial distortion of the projected image, and good cleanability. I understand.

1 Transmissive screen 2 Light-diffusing fine particles 3 Light-diffusing layer 4 Light-transmitting support 5 Xerogel 6A-6C Adhesive layer 7 Light-transmitting base material 8 Separate base material 9 Intermediate base material 10 Adhesive base material 100 Transmissive screen laminated body

Claims (1)

A transmissive screen having a light-diffusing layer containing light-diffusing fine particles and xerogel, a pressure-sensitive adhesive layer, and a light-transmitting base material on at least one surface of the light-transmitting support, wherein the light- diffusing fine particles are formed. Single particle-dispersible light-diffusing fine particles having an average primary particle diameter of 0.10 μm or more and 200 μm or less, and aggregated particle-dispersible light-diffusing fine particles having an average secondary particle diameter of more than 1.0 μm and an upper limit of 200 μm. The xerogel is composed of inorganic fine particles and a resin binder, and the inorganic fine particles are at least one selected from amorphous synthetic silica, alumina, and alumina hydrate, and the resin binder is completely or partially saponified polyvinyl. It is an alcohol, the content of the resin binder is 5 to 70% by mass with respect to the inorganic fine particles, the dry solid content coating amount of the light diffusion layer is 5 to 30 g / m ² , and the pressure-sensitive adhesive layer is A transmissive screen containing an acrylic pressure-sensitive adhesive, the solid content of the pressure-sensitive adhesive layer is 18 to 50 g / m ² , and the thickness of the light-transmitting base material is 12 to 50 μm.

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