Transparent sheet

Abstract

To provide a transparent sheet which includes a glass fiber cloth, a resin layer included in a state of being impregnated in the glass fiber cloth, and a cover layer laminated on at least one surface side of the resin layer, and is hardly burned and spread when the sheet contacts with flame.SOLUTION: A transparent sheet includes a glass fiber cloth, a resin layer included in a state of being impregnated in the glass fiber cloth, and a cover layer laminated on at least one surface side of the resin layer. The transparent sheet is such that: the cover layer contains a vinyl-chloride resin; a chloride concentration is 40% or more; the total light transmittance of the transparent sheet is 80% or more; and a haze is 30% or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a transparent sheet comprising a transparent resin composite of glass fiber cloth and resin. [Background technology]

[0002] The Building Standards Act and its Enforcement Order stipulate that smoke exhaust systems must be installed to prevent the flow of smoke, toxic gases, etc. that are generated in the event of a fire in a building, and to facilitate evacuation and firefighting activities. Therefore, office buildings, commercial facilities, and other buildings often have smoke exhaust systems and smoke barriers such as vertical smoke barriers installed.

[0003] Hanging smoke barriers are usually attached to the ceilings of buildings to temporarily block the flow of smoke, toxic gases, etc. into corridors and upper floors in the event of a fire, thereby ensuring the time necessary for evacuation. For this reason, transparent plate glass, transparent resin composites of glass fiber and resin, etc. are used as hanging smoke barriers to prevent them from obstructing the view or spoiling the aesthetics. Transparent resin composites of glass fiber and resin have the advantage of being less likely to break than transparent plate glass.

[0004] Patent Document 1 discloses a non-flammable sheet having at least one glass fiber fabric and a photo-curable resin impregnated into the glass fiber fabric, wherein the difference in refractive index between the glass composition constituting the glass fibers in the glass fiber fabric and the photo-curable resin is 0.02 or less, the proportion of the glass fiber fabric to the non-flammable sheet is 20 to 70% by weight, the proportion of the photo-curable resin to the non-flammable sheet is 80 to 30% by weight, and the photo-curable resin is obtained by curing a composition containing at least a brominated vinyl ester.

[0005] Patent Document 2 discloses a transparent noncombustible sheet having an intermediate layer formed by impregnating a glass fiber fabric with a styrene-based thermoplastic elastomer, and vinyl chloride resin layers laminated on both sides of the intermediate layer via an acrylic resin layer, the acrylic resin layer containing acrylic-styrene copolymer resin particles, the sheet having a total light transmittance of 80% or more and a haze of 30% or less. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-213489 [Patent Document 2] Japanese Patent Publication No. 2020-69710 Summary of the Invention [Problem to be solved by the invention]

[0007] By the way, the outline of the certification standard for non-combustible materials under the Building Standards Act is a radiation intensity of 50 kW / m2 in a cone calorimeter test. 2 In a 20-minute heating and combustion test, (1) the total calorific value was 8MJ / m 2 (2) 200 kW / m 2 (2) The heat generation time exceeding the specified value is less than 10 seconds, and (3) no cracks or penetrations reaching the back surface occur. These criteria can be said to be the property that the material does not allow flames to burn through, but they do not necessarily mean that the material itself does not have the property of not spreading when it comes into contact with flames.

[0008] Therefore, the main object of the present invention is to solve the above problems and to provide a transparent sheet that is less susceptible to the spread of fire when it comes into contact with a flame. [Means for solving the problem]

[0009] The present inventors have conducted research to solve the above problems and have found that the above problems can be solved by providing a transparent sheet comprising a glass fiber cloth, a resin layer impregnated in the glass fiber cloth, and a cover layer laminated on at least one side of the resin layer, wherein the cover layer contains a vinyl chloride resin and has a chlorine concentration of 40% or more. The present invention was completed based on these findings and further research.

[0010] That is, the present invention provides the following aspects of the invention. Item 1. A transparent sheet comprising a glass fiber cloth, a resin layer impregnated in the glass fiber cloth, and a cover layer laminated on at least one side of the resin layer, wherein the cover layer contains a vinyl chloride resin and has a chlorine concentration of 40% or more, and the transparent sheet has a total light transmittance of 80% or more and a haze of 30% or less. [Effects of the Invention]

[0011] According to the transparent sheet of the present invention, the transparent sheet comprises a glass fiber cloth, a resin layer impregnated in the glass fiber cloth, and a cover layer laminated on at least one side of the resin layer, wherein the cover layer contains a vinyl chloride resin and has a chlorine concentration of 40% or more, and the transparent sheet has a total light transmittance of 80% or more and a haze of 30% or less, making it difficult for the sheet to spread fire when it comes into contact with a flame. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view illustrating one embodiment of a transparent sheet of the present invention. [Figure 2] This is a schematic diagram illustrating the device used to test how flames spread when they come into contact with a transparent sheet. DETAILED DESCRIPTION OF THE INVENTION

[0013] The transparent sheet of the present invention comprises a glass fiber cloth, a resin layer impregnated in the glass fiber cloth, and a cover layer laminated on at least one side of the resin layer, wherein the cover layer contains a vinyl chloride resin and has a chlorine concentration of 40% or more, and the transparent sheet has a total light transmittance of 80% or more and a haze of 30% or less. The transparent sheet of the present invention will be described in detail below.

[0014] For example, as shown in FIG. 1, the transparent sheet 1 of the present invention includes a glass fiber cloth 2, a resin layer 3 impregnated in the glass fiber cloth 2, and a cover layer 4 laminated on at least one side of the resin layer 3.

[0015] The transparent sheet 1 of the present invention may contain at least one glass fiber cloth 2, or may contain multiple glass fiber cloths. As shown in FIG. 1 , the resin layer 3 fills the gaps between the glass fibers constituting the glass fiber cloth 2, and one surface side of the resin layer 3 communicates with the other surface side through the gaps. To enhance transparency, the transparent sheet 1 of the present invention preferably has the resin layer 3 formed on at least one surface of the glass fiber cloth 2 layer, as shown in FIG. 1 , and more preferably has the resin layer 3 formed on both surfaces of the glass fiber cloth 2 layer. The transparent sheet 1 of the present invention also preferably has the cover layer 4 laminated on at least one surface of the resin layer 3, more preferably on both surfaces of the resin layer 3. The cover layer 4 is preferably disposed so as to be the outermost surface of the transparent sheet 1. The transparent sheet 1 of the present invention may also contain layers other than the glass fiber cloth 2, the resin layer 3, and the cover layer 4.

[0016] (glass fiber cloth 2) In the transparent sheet 1 of the present invention, the glass fiber cloth 2 is contained in a state in which it is impregnated with a resin layer 3, which will be described later. In the transparent sheet 1 of the present invention, the glass fiber cloth 2 contributes to increasing the mechanical strength of the sheet. The refractive index of the glass fiber cloth 2 can be set to be similar to the refractive index of the resin layer 3, which will be described later. This allows the transparent sheet 1 of the present invention to have a total light transmittance of 80% or more and a haze of 30% or less, which are indicators of transparency, as will be described later. In other words, the total light transmittance of 80% or more and a haze of 30% or less, which are indicators of transparency possessed by the transparent sheet 1 of the present invention, indicates that at least the refractive index of the glass fiber cloth 2 and the refractive index of the resin layer 3, which will be described later, are sufficiently similar (for example, the difference between the refractive index of the glass fiber cloth 2 and the refractive index of the resin layer 3 is 0.02 or less).

[0017] In the transparent sheet 1 of the present invention, the glass fiber cloth 2 is composed of a plurality of glass fibers. In the glass fiber cloth 2, the plurality of glass fibers are entangled with each other to form a single piece of cloth. The glass fiber cloth 2 may be, for example, a glass fiber fabric (glass cloth) composed of a plurality of warp threads and a plurality of weft threads. The weave of the glass fiber fabric is not particularly limited, and examples thereof include plain weave, satin weave, twill weave, basket weave, and rib weave. The weave density of the glass fiber fabric is not particularly limited, and examples thereof include 20 to 100 threads / 25 mm or more for both the warp and weft, and preferably 20 to 80 threads / 25 mm or more.

[0018] The glass material of the glass fibers constituting the glass fiber cloth 2 is not particularly limited, and for example, known glass materials can be used. Examples of glass materials include alkali-free glass (E glass), acid-resistant alkali-containing glass (C glass), high-strength, high-elasticity glass (S glass, T glass, etc.), and alkali-resistant glass (AR glass), and preferably the versatile alkali-free glass (E glass). The glass fibers constituting the glass fiber cloth 2 may be made of one type of glass material or a combination of two or more types of glass fibers made of different glass materials. Furthermore, from the viewpoint of improving transparency, it is preferable to select a glass material whose refractive index is close to that of the resin layer 3, which will be described later.

[0019] The count of the glass fibers constituting the glass fiber cloth 2 is not particularly limited as long as it can form the glass fiber cloth 2. From the viewpoint of improving transparency, the count of the glass fibers is preferably 20 tex or less, more preferably 3 to 6 tex, and more preferably 3 to 5 tex. The count of the glass fibers may be one type alone or two or more types may be combined. The tex count of the glass fibers corresponds to the number of grams per 1000 m.

[0020] The glass fibers constituting the glass fiber cloth 2 are preferably glass yarns in which a plurality of single filaments, which are long glass fibers, are twisted together. The number of single filaments in the glass yarn is preferably about 30 to 400, and more preferably about 40 to 120. The diameter of a single filament in the glass yarn is preferably about 3.0 to 6.0 μm, and more preferably about 3.0 to 5.0 μm, from the viewpoint of suppressing color bleeding of the transparent sheet 1. The count of the glass yarn is preferably 3 to 30 tex, more preferably 3 to 12 tex, and even more preferably 3 to 5 tex, from the viewpoint of suppressing color bleeding.

[0021] In the transparent sheet 1, the proportion (mass %) of the glass fiber cloth 2 relative to the total mass of the glass fiber cloth 2 and the resin layer 3 is preferably 5 to 50 mass %, more preferably 10 to 35 mass %, and particularly preferably 20 to 30 mass %, from the viewpoint of achieving both transparency and a lower total heat release amount and heat release rate in the heat release test of the certification standard for non-combustible materials in the Building Standards Act. 2 ) is 10 to 120 (g / m 2 ) is preferred, and 10 to 60 (g / m 2 ) is more preferable, and 10 to 40 (g / m 2 ) is more preferred.

[0022] The difference in refractive index between the glass fiber cloth 2 and the resin layer 3 described below is preferably 0.05 or less, more preferably 0.02 or less, and even more preferably 0.01 or less. The refractive index of the glass fiber cloth 2 is preferably about 1.45 to 1.65, and more preferably about 1.50 to 1.60.

[0023] The refractive index of the glass fiber cloth 2 is measured in accordance with the B method of JIS K 7142:2008. Specifically, the glass fibers constituting the glass fiber cloth 2 are immersed in methylene iodide (n D 23 1.747), butyl phthalate (n D 23 1.491) and dimethyl carbonate (n D 23 1.366), an Abbe refractometer NAR-2T manufactured by Atago Co., Ltd. was used as a light source, and sodium D line with a wavelength of 589 nm was used as a light source, and measurements were carried out at a temperature of 23°C, and the average value of five tests was taken as the refractive index value. The refractive index of the resin layer 3 was measured in accordance with the B method of JIS K 7142:2008. Specifically, the cured or solidified resin layer 3 was powdered, and the powder was immersed in methylene iodide (n D 23 1.747), butyl phthalate (n D 23 1.491) and dimethyl carbonate (n D 231.366), and a small measuring microscope STM5-311 (Olympus, observation magnification 400x) was used as the microscope, and measurements were taken at a temperature of 23°C using sodium D line with a wavelength of 589 nm as the light source, and the average value of 5 tests was taken as the refractive index value.

[0024] The difference in Abbe number between the glass fiber cloth 2 and the resin layer 3 is preferably 30 or less, more preferably 20 or less, and even more preferably 10 or less. The Abbe number of the glass fiber cloth 2 is preferably 30 to 80, more preferably 40 to 70, and even more preferably 50 to 65. The Abbe numbers of the resin layer and the glass fiber cloth are measured as follows.

[0025] (Abbe number of resin layer) A sheet of the cured resin composition not containing glass fiber cloth was prepared under the same conditions and thickness as the case containing glass fiber cloth, and a test piece was cut to a width of 8 mm and a length of 20 mm. The surface was well polished, and the refractive index at a wavelength of 589 nm was measured in accordance with JIS K 7142A using an Abbe refractometer NAR-2T manufactured by Atago Co., Ltd., diiodomethane as the contact liquid, and sodium D line with a wavelength of 589 nm as the light source at a measurement temperature of 23° C. Next, the dispersion value was measured and calculated using natural light as the light source, and the Abbe number was calculated according to the following formula (I). Abbe number = (refractive index at wavelength 589 nm - 1) / dispersion value (I)

[0026] (Abbe number of glass fiber cloth) A glass sheet 8 mm wide, 20 mm long, and 5 mm thick was prepared using the glass material that constitutes the glass fiber, and the surface was thoroughly polished. The refractive index at a wavelength of 589 nm was measured in accordance with JIS K 7142A using an Abbe refractometer NAR-2T manufactured by Atago Co., Ltd., diiodomethane as the contact liquid, and sodium D line with a wavelength of 589 nm as the light source at a measurement temperature of 23° C. Next, the dispersion value was measured and calculated using natural light as the light source, and the Abbe number was calculated according to the above formula (I).

[0027] The thickness of the glass fiber cloth 2 is, for example, about 10 to 100 μm, and from the viewpoint of suppressing color bleeding, it is preferably 10 to 55 μm, and more preferably about 10 to 35 μm. When the thickness of the glass fiber cloth 2 is 10 to 35 μm, it is particularly preferable that the glass fiber cloth 2 has a glass volume fraction of 38% or more as calculated by the following formula (II). A glass fiber cloth 2 having a thickness of 10 to 35 μm and a glass volume fraction of 38% or more can be obtained, for example, by subjecting glass fibers to an opening treatment.

[0028] Glass volume (%) = (A / (B × C)) × 100 (II) A: Mass of glass fiber cloth (g / m 2 ) B: Specific gravity of the glass material that makes up the glass fiber cloth (g / m 3 ) C: Thickness of the glass fiber cloth (m)

[0029] (Resin layer 3) In the transparent sheet 1 of the present invention, the resin layer 3 is impregnated into the glass fiber cloth 2 and is formed by curing or solidifying a resin-containing resin composition. Specifically, the resin layer 3 can be a curable resin layer or a thermoplastic resin layer. When a cured resin layer is used, the resin composition containing a curable resin can be cured by applying energy such as light or heat to the resin composition (a photocured resin composition or a thermoset resin composition). When a thermoplastic resin layer is used, the resin layer can be a cured product obtained by drying and solidifying the thermoplastic resin composition.

[0030] From the viewpoint of further improving the transparency of the transparent sheet 1, the curable resin is preferably one that can approximate the refractive index of the resin layer 3 to that of the glass fiber cloth 2 described above. Preferable curable resins are those that produce photocurable curable resin compositions, such as vinyl ester resins (bisphenol A vinyl ester resins), brominated vinyl ester resins (brominated bisphenol A vinyl ester resins), urethane (meth)acrylate resins, fluorine-containing (meth)acrylate resins, fluorene (meth)acrylate resins, unsaturated polyester resins, curable acrylic resins, and epoxy resins. Among these, the curable resin layer is preferably one that satisfies the requirements for the total calorific value and heat release rate (radiant intensity of 50 kW / m in a cone calorimeter test) in the heat release test of the certification standard for non-combustible materials in the Building Standards Act. 2 In a 20-minute heating and combustion test, (1) the total calorific value was 8MJ / m 2 (2) 200 kW / m 2 From the viewpoint of making it easier to lower the heat generation time (a heat generation time exceeding 10 seconds or less), it is preferable for the cured product to contain a brominated vinyl ester resin, and it is more preferable for the cured product to be formed from a resin composition containing a brominated vinyl ester resin and a fluorinated (meth)acrylate. Examples of fluorinated (meth)acrylates include 2,2,2-trifluoroethyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, 2-(perfluorohexyl)ethyl methacrylate, and 2-(perfluorobutyl)ethyl methacrylate. The refractive index of brominated vinyl ester resins is about 1.6, and the refractive index of fluorinated (meth)acrylates is about 1.3 to 1.4. On the other hand, the refractive index of glass fibers with a general-purpose glass composition is about 1.53 to 1.57. Therefore, the mass ratio of the brominated vinyl ester resin to the fluorinated (meth)acrylate may be appropriately adjusted depending on the refractive index of the glass fiber used. For example, the mass of the brominated vinyl ester resin / the mass of the fluorinated (meth)acrylate may be 1 to 10, preferably 2 to 8, and more preferably 3 to 5.

[0031] From the viewpoint of improving the transparency of the transparent sheet 1, the thermoplastic resin is preferably one that can approximate the refractive index of the resin layer 3 and the glass fiber cloth 2. Examples of preferred thermoplastic resins include polyvinyl chloride resin, saturated polyester resin, polyolefin resin, thermoplastic acrylic resin, polycarbonate resin, polyvinyl alcohol resin, ethylene-vinyl acetate copolymer, polyamide resin, and polyarylate resin. For example, when E-glass is used as the glass material for the glass fibers constituting the glass fiber cloth 2, polyvinyl chloride resin, saturated polyester resin, and thermoplastic acrylic resin are preferred from the viewpoint of refractive index. One type of thermoplastic resin may be used alone, or two or more types with different refractive indices may be used in combination to approximate the refractive index of the glass fiber used. In the transparent sheet 1 of the present invention, when the resin layer 3 is a thermoplastic resin layer, the portion impregnated into the glass fiber cloth 2 is preferably impregnated with a thermoplastic resin composition in a sol state or dissolved in a solvent, and solidified (by heating or drying).

[0032] The resin composition forming the resin layer 3 may further contain additives such as a curing accelerator, a flame retardant, an ultraviolet absorber, a filler, and a photopolymerization initiator. Examples of flame retardants include aluminum hydroxide, magnesium hydroxide, trichloroethyl phosphate, triallyl phosphate, ammonium polyphosphate, and phosphoric acid ester. Examples of ultraviolet absorbers include benzotriazole. Examples of fillers include calcium carbonate, silica, and talc. Photopolymerization initiators include 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 2-methyl Examples of suitable methylbenzoyl compounds include 2-benzyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

[0033] In the present invention, in order to enhance the transparency of the transparent sheet, it is desirable to set the refractive index of the glass fiber cloth 2 to be similar to that of the resin layer 3. From this viewpoint, the refractive index of the resin layer 3 is preferably about 1.45 to 1.65, and more preferably about 1.50 to 1.60.

[0034] In the transparent sheet 1 of the present invention, the mass of the resin layer 3 is, for example, 20 to 400 g / m 2 and 20 to 100 g / m 2The thickness of the resin layer 3 is, for example, 20 to 500 μm, and more preferably 30 to 150 μm.

[0035] (Cover layer 4) In the transparent sheet 1 of the present invention, the cover layer 4 is laminated on at least one side of the resin layer 3. The cover layer 4 contains a vinyl chloride resin and has a chlorine concentration of 40% or more, so that the chlorine atom concentration is high and the sheet is less likely to spread fire when it comes into contact with a flame. From the viewpoint of achieving both greater fire resistance when the sheet comes into contact with a flame and easier handling, the chlorine concentration is preferably 45 to 55% by mass, and more preferably 45 to 50% by mass.

[0036] In the present invention and specification, the chlorine concentration of the cover layer 4 is a value measured using energy dispersive X-ray analysis (EDS analysis). To achieve a high chlorine concentration, for example, the vinyl chloride resin content of the cover layer 4 can be increased.

[0037] The vinyl chloride resin is preferably a vinyl chloride resin or a chlorinated vinyl chloride resin. The cover layer 4 can be formed by laminating a sheet or film formed of the vinyl chloride resin on at least one side of the resin layer 3. Examples of commercially available cover layers 4 include a rigid vinyl chloride sheet, Mataeron (registered trademark), product number CB-N-MO, manufactured by Matanaga Chemical Co., Ltd.

[0038] The thickness of one cover layer 4 is not particularly limited, but may be, for example, 50 to 300 μm, and preferably 100 to 200 μm. The mass of one cover layer 4 is not particularly limited, but may be, for example, 70 to 450 g / m 2 and 150 to 300 g / m 2The ratio of the thickness of the resin layer 3 to the thickness of one cover layer 4 (resin layer 3 / cover layer 4) is not particularly limited, but may be, for example, 0.1 to 10, preferably 1 to 5, and more preferably 1.5 to 4. The ratio of the thickness of the entire transparent sheet 1 to the thickness of one cover layer 4 (transparent sheet 1 / cover layer 4) may be, for example, 0.1 to 10, preferably 1 to 5, and more preferably 1.5 to 4.

[0039] Furthermore, in order to make the cover layer 4 less likely to peel off when it is directly laminated onto the resin layer 3, the cover layer 4 may be subjected to a surface treatment such as a corona treatment, a flame treatment, or a plasma treatment.

[0040] (Transparent Sheet 1 Characteristics) The transparent sheet of the present invention has a total light transmittance of 80% or more and a haze of 30% or less. In this specification, the total light transmittance of the transparent sheet 1 is a value measured in accordance with Japanese Industrial Standard JIS K 7361-1:1997, "Test method for total light transmittance of plastic-transparent materials - Part 1: Single beam method." The haze of the transparent sheet 1 is a value measured in accordance with Japanese Industrial Standard JIS K7136 2000, "Determination of haze of plastic-transparent materials." The transparent sheet of the present invention preferably has a total light transmittance of 85% or more, more preferably 90% or more. Furthermore, the haze of the transparent sheet of the present invention is preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less.

[0041] The mass of the transparent sheet 1 of the present invention is not particularly limited, but is, for example, 100 to 800 g / m 2 , preferably 200 to 600 g / m 2 The thickness of the transparent sheet 1 of the present invention is, for example, 80 to 600 μm, and preferably 150 to 500 μm.

[0042] (Use of transparent sheet 1) The transparent sheet 1 of the present invention can be suitably used as a material for constituting smoke-proof hanging walls, smoke-proof sheets, partition walls, smoke-proof curtains, touch panels, solar panels (back sheets, etc.), or as a membrane material used for roofing materials, lighting tents, etc.

[0043] (Method of manufacturing transparent sheet 1) The transparent sheet 1 of the present invention can be manufactured by the following method. First, the glass fiber cloth 2 and the uncured cured resin composition constituting the resin layer 3 are prepared. The cured resin composition is applied to a film to be used as the cover layer 4, and the glass fiber cloth 2 is placed on top of the cured resin composition to impregnate the glass fibers with the cured resin composition. Another film to be used as the cover layer 4 is then placed on the glass fiber cloth 2. Pressure is applied to the surfaces of the two cover layers 4, and the glass fiber cloth 2 is further impregnated with the cured resin composition. The cured resin composition is cured by heating or light irradiation, resulting in a transparent sheet 1 in which the resin layer 3 is impregnated into the glass fiber cloth 2 and the cover layer 4 is laminated on the resin layer 3 (transparent sheet 1 laminated in the order cover layer 4 / resin layer 3 impregnated in the glass fiber cloth 2 / cover layer 4). When the cover layer 4 is laminated on one side of the resin layer 3, one of the two cover layers 4 included in the transparent sheet 1 can be simply peeled off.

[0044] The transparent sheet 1 of the present invention can also be produced by the following method. First, the glass fiber cloth 2 and the thermoplastic resin composition constituting the resin layer 3 are prepared. Next, two films to be used as the cover layer 4 are prepared, the thermoplastic resin composition is applied to the films, the glass fiber cloth 2 is placed on top of the thermoplastic resin composition, and the glass fiber 2 is impregnated with the thermoplastic resin composition. Another film to be used as the cover layer 4 is placed on the glass fiber cloth 2, and pressure is applied to the surface of each of the two cover layers 4 to further impregnate the glass fiber cloth 2 with the thermoplastic resin composition. The thermoplastic resin composition is then dried and solidified, thereby obtaining a transparent sheet 1 in which the resin layer 3 is impregnated into the glass fiber cloth 2 and the cover layer 4 is laminated on the resin layer 3 (transparent sheet 1 laminated in the order of cover layer 4 / resin layer 3 impregnated in the glass fiber cloth 2 / cover layer 4). [Example]

[0045] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0046] 1. Measurement and evaluation methods 1-1. Average diameter (μm) and number of single fibers of glass yarn Two pieces of glass fiber cloth were cut into 30 cm squares, one for observing the warp yarns and the other for observing the weft yarns, and each was embedded in epoxy resin (product name "3091", manufactured by Marumoto Struers K.K.) and cured. Next, the glass cloth embedded in the epoxy resin was polished to an extent that the cross section of the single fibers constituting the warp or weft yarns could be observed, and the average single fiber diameter (μm) and the number of single fibers (number of fibers) of the glass yarn were measured by observing them at a magnification of 500 times using a scanning electron microscope (SEM) (product name "JSM-6390A", manufactured by JEOL Ltd.). (1) Average single fiber diameter of long glass fibers (μm) Twenty warp and weft yarns were randomly selected, and the cross sections of all the single fibers contained in each of the 20 glass yarns were observed, the diameters were measured, and the average value was calculated to obtain the average single fiber diameter of the warp and weft yarns. (2) Number of single fibers (pieces) Twenty warp and weft yarns were randomly selected, and the total number of single fibers contained in each of the 20 glass yarns was measured and the average value was calculated to determine the number of single fibers in the warp and weft yarns.

[0047] 1-2.Glass yarn count The count of the glass yarn was measured according to the method specified in "7.1 Count" of the Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers." Specifically, 500 m of glass yarn was first taken from the winding machine and used as a test piece. The test piece was placed flat in a muffle furnace and baked at 625°C for 25 minutes, then allowed to cool in a desiccator, and the mass of the test piece was measured. The count was calculated according to the following formula: (formula) t=(m / 500)×1000 t: count m: mass of test piece (g)

[0048] 1-3.Glass fiber cloth 2 weave density (threads / 25mm) The weave density of the glass fiber cloth 2 was measured for the warp and weft threads according to the method specified in "7.9 Density (Weave Density)" of the Japanese Industrial Standard JIS R 3420:2013 "General Test Methods for Glass Fibers." Specifically, the measurement targets were positions 50 mm or more away from the edges and selvages of the glass fiber cloth 2, with measurement intervals set to 10 mm or more and 200 mm or less, and the total number of threads within the set measurement interval was counted. This was counted as one measurement, and the measurement was then moved to another position that did not include the previously measured thread, and the total number of threads within the measurement interval was counted two more times in the same manner. For each of the three measurements, the number of threads per 25 mm was calculated using the following formula, and the average of the three measurements was calculated. (formula) Mi=(ni / ai)×25 Mi: Number of threads per 25mm ni: Number of measured yarns ai: the exact distance at which the measurement was taken (mm)

[0049] 1-4. Thickness of glass fiber cloth 2 (μm) The thickness of the glass fiber cloth 2 was measured in accordance with Method A specified in "7.10.1 Cloth Thickness" of the Japanese Industrial Standard JIS R3420:2013 "General Test Methods for Glass Fibers." Specifically, using a micrometer, the spindle was gently rotated to lightly contact the measurement surface parallel to it, and the thickness of the glass fiber cloth 2 was measured by reading the scale after the ratchet made three clicks. The thickness of the glass fiber cloth 2 was measured at the intersection of the warp and weft threads.

[0050] 1-5. Refractive index of the glass fiber cloth 2 and the resin layer 3 The refractive indices of the glass fiber cloth 2 and the resin layer 3 were measured in accordance with "Method B" specified in the Japanese Industrial Standard JIS K 7142:2008 "Plastics - Determination of Refractive Index." Specifically, the glass fibers constituting the glass fiber cloth 2 and the resin layer 3 were first crushed to an extent that Becke lines could be observed when observed under an optical microscope at 400x magnification, and used as a measurement sample. Separately, multiple immersion solutions with refractive indices differing by 0.002 were prepared. A small amount of the immersion solution was placed on a glass slide, and several grains of the measurement sample were placed in the immersion solution on the glass slide, followed by a cover glass. A halogen lamp equipped with a D-line interference filter was used as the light source. The measurement sample was focused on using an optical microscope at 400x magnification, and then the microscope stage and objective lens were moved slightly away from the focus. By this procedure, if the refractive index of the measurement sample does not match that of the immersion liquid, the Becke lines (i.e., the bright halo visible around or inside the powder) will shift to the higher refractive index, and if the refractive index of the measurement sample matches that of the immersion liquid, the Becke lines will not appear. The refractive index was measured by repeating the measurement until the refractive index of the measurement sample matches that of the immersion liquid or falls between two adjacent refractive indices in the series of immersion liquids. The refractive index was measured three times at a temperature of 23°C, and the average of the three measurements was taken as the refractive index.

[0051] 1-6. Mass of glass fiber cloth 2 (g / m 2 ) The mass of the glass fiber cloth 2 was measured in accordance with the method specified in "7.2 Mass (mass) of cloths and mats" of the Japanese Industrial Standard JIS R 3420:2013 "General test methods for glass fibers." Specifically, a 100 cm2 area was measured from a point 50 mm or more away from the edge of the glass fiber cloth 2. 2 A square test piece was taken and dried at 105°C for 1 hour, after which the mass of the test piece was measured and calculated as 1m according to the following formula: 2 The mass per unit was calculated. (formula) ρA=(ms / 100)×10 4 ρA:1m 2 Mass per unit (g / m2 ) ms: mass of test piece (g)

[0052] 1-7. Chlorine concentration (mass%) of cover layer 4 The chlorine concentration in the cover layer 4 was measured by energy dispersive X-ray analysis (EDS analysis). Specifically, a measurement sample was prepared by cutting the transparent sheet 1 into a size of 1 cm length x 1 cm width. The chlorine concentration in the cover layer 4 was measured using a scanning electron microscope (product name "JSM-6390A", manufactured by JEOL Ltd.) equipped with an EDS analyzer at a magnification of 600x, with the surface of the measurement sample set as the measurement surface and the vicinity of the center of the measurement sample as the measurement point.

[0053] 1-8. Total light transmittance (%) and haze (%) The total light transmittance of the transparent sheet 1 was measured in accordance with Japanese Industrial Standard JIS K 7361-1:1997 "Test method for total light transmittance of plastic transparent materials - Part 1: Single beam method." The haze of the transparent sheet 1 was measured in accordance with Japanese Industrial Standard JIS K 7136:2000 "Determination of haze of plastic transparent materials."

[0054] 1-9. Testing the spread of flame when flame comes into contact with a transparent sheet Figure 2 is a schematic diagram illustrating the testing equipment used to measure the spread of flame when it comes into contact with a transparent sheet. Transparent sheet 1 was cut into a rectangle 3 cm wide and 15 cm long, and as shown in Figure 2, the transparent sheet was hung from a stand using a clip so that the lengthwise direction was facing downward. Then, using a turbo lighter (product name Crater Neo F DJ-03M-F, manufactured by LITEC Corporation), the tip of the flame was applied to the bottom edge of transparent sheet 1 for 5 seconds, and the transparent sheet 1 was observed, and the length of the flame spread along the length of transparent sheet 1 was measured. A value of 5 cm or less was considered a pass.

[0055] 1-10. Degree of deformation of a transparent sheet in a test of how flame spreads when the transparent sheet comes into contact with flame A test was carried out to see how the flame spread when the transparent sheet came into contact with a flame, and the degree of deformation of the transparent sheet was observed and evaluated according to the following criteria. A: The transparent sheet rippled slightly, but it did not curl up and remained hanging. B: The transparent sheet was curled up like a spiral spring in the length direction and was significantly deformed.

[0056] 2. Transparent sheet manufacturing [Example 1] (Preparation of fiberglass cloth 2) Glass yarns (product name "ECBC1500 1 / 0 0.5Z", manufactured by Unitika Glass Fiber Co., Ltd.; average single fiber diameter 4 μm, single fiber count 100, twist count 0.5Z, count 3.4 tex) were used as warp and weft yarns. These were woven on an air jet loom to obtain a plain weave glass fiber fabric with a warp density of 75 / 25 mm and a weft density of 75 / 25 mm. The spinning and weaving sizing agents adhering to the resulting glass fiber fabric were then removed by heating at 400°C for 30 hours. The glass fiber fabric was then treated with a surface treatment agent containing a silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride), manufactured by Chisso Corporation) adjusted to a concentration of 15 g / L, squeezed with a padder roll, and then dried at 120°C for 1 minute for curing. The glass fiber fabric was then subjected to a water jet processing at a pressure of 1.5 MPa, with the warp tension of the fabric set to 100 N / m, and a width-widening treatment was carried out once to obtain a glass fiber fabric 2 (glass fiber fabric). The obtained glass fiber fabric 2 had a warp density of 75 threads / 25 mm, a weft density of 75 threads / 25 mm, a thickness of 20 μm, and a mass of 19 g / m. 2 The refractive index was 1.561. The average single fiber diameter and the number of single fibers of the glass yarn were measured using the glass fiber cloth 2.

[0057] (Preparation of curable resin solution used to form resin layer 3) As the curable resin solution to be used to form the resin layer 3, a brominated vinyl ester resin (product name "Neopol 8197", manufactured by Japan U-Pica Co., Ltd.), a fluorine-containing (meth)acrylate (product name "Light Ester M-3F", manufactured by Kyoeisha Chemical Co., Ltd., trifluoroethyl methacrylate), and a photopolymerization initiator (product name "Omnirad 184", manufactured by IGM) were prepared and mixed in the mass ratio shown in Table 1 to prepare the curable resin solution.

[0058] (Preparation of cover layer 4) A hard vinyl chloride sheet (product name "Mataeron (registered trademark) product number CB-N-MO", manufactured by Matanaga Chemical Industry Co., Ltd., vinyl chloride resin content 88%) was prepared as the cover layer 4. The thickness of the sheet was 150 μm and the mass was 210 g / m 2 Then, one surface of the sheet was subjected to a corona treatment. Two sheets were prepared.

[0059] (Manufacturing of transparent sheet 1) The prepared curable resin solution for the resin layer 3 was applied to the corona-treated surface of one of the sheets for the cover layer 4. Next, the prepared glass fiber cloth 2 was placed on top of the curable resin solution and left to stand for 1 minute, allowing the curable resin solution to penetrate into the gaps in the glass fiber cloth 2. Next, another sheet for the cover layer 4 was placed on top of it with the corona-treated surface facing the curable resin solution, and a roller was used to roll the sheet for the cover layer 4 until the mass of the resin layer 3 reached 50 g / m. 2 Thereafter, the curable resin solution for the resin layer 3 was irradiated with light using a black light fluorescent lamp (product name FL15BLB, manufactured by Toshiba Corporation) through the sheet for the cover layer 4 (light irradiation conditions: cumulative light amount 200 mJ / cm 2 ) and curing the curable resin solution to form a resin layer 3, thereby obtaining a transparent sheet 1 of the present invention having a laminated structure of cover layer 4 / resin layer 3 contained in a state of being impregnated in glass fiber cloth 2 / cover layer 4. In the obtained transparent sheet, the resin layer 3 (cured product of the curable resin) was impregnated into the gaps between the glass fibers of the glass fiber cloth, and the resin layer 3 was formed on both sides of the glass fiber cloth layer.

[0060] [Example 2] (Preparation of fiberglass cloth 2) The same glass fiber cloth 2 as in Example 1 was prepared.

[0061] (Preparation of curable resin solution used to form resin layer 3) The same curable resin solution as in Example 1 was prepared.

[0062] (Preparation of cover layer 4) A hard vinyl chloride sheet (product name "Mataeron (registered trademark) product number CB-N-MO", manufactured by Matanaga Chemical Industry Co., Ltd., vinyl chloride resin content 88%) was prepared as the cover layer 4. The thickness of the sheet was 150 μm and the mass was 210 g / m 2 One sheet was prepared, and one surface of the sheet was subjected to a corona treatment.

[0063] (Preparing the process sheet) A hard vinyl chloride sheet (product name "Mataeron (registered trademark) product number CB-N-MO", manufactured by Matanaga Chemical Industry Co., Ltd., vinyl chloride resin content 88%) was prepared as a process sheet. The thickness of the sheet was 150 μm and the mass was 210 g / m 2 It was.

[0064] (Manufacturing of transparent sheet 1) The prepared curable resin solution for the resin layer 3 was applied to the corona-treated surface of one of the sheets for the cover layer 4. Next, the prepared glass fiber cloth 2 was placed on the curable resin solution and left to stand for 1 minute to impregnate the gaps in the glass fiber cloth 2 with the curable resin solution. Next, the process sheet was placed on the curable resin solution, and a roller was used to roll the process sheet from above until the mass of the resin layer 3 reached 50 g / m. 2 Thereafter, the curable resin solution to be used as the resin layer 3 was irradiated with light using a black light fluorescent lamp (product name: FL15BLB, manufactured by Toshiba Corporation) (light irradiation conditions: cumulative light amount 200 mJ / cm 2 ) to cure the curable resin solution, forming a resin layer 3, and the process sheet was peeled off to obtain a transparent sheet 1 of the present invention, which has a laminated structure of a cover layer 4 and the resin layer 3 contained in an impregnated state in the glass fiber cloth 2. In the obtained transparent sheet, the resin layer 3 (a cured product of the curable resin) was impregnated into the gaps between the glass fibers of the glass fiber cloth, and the resin layer 3 was formed on both sides of the glass fiber cloth layer.

[0065] [Example 3] (Preparation of fiberglass cloth 2) The same glass fiber cloth 2 as in Example 1 was prepared.

[0066] (Preparation of curable resin solution used to form resin layer 3) As the curable resin solution to be used to form the resin layer 3, a brominated vinyl ester resin (trade name "Neopol 8197", manufactured by Japan U-Pica Co., Ltd.), a bisphenol A type vinyl ester resin (trade name "Neopol 8114", manufactured by Japan U-Pica Co., Ltd.), neopentyl glycol diacrylate (trade name "NK Ester A-NPG", manufactured by Shin-Nakamura Chemical Co., Ltd.), and a photopolymerization initiator (trade name "Omnirad 184", manufactured by IGM) were prepared and mixed to the mass ratio shown in Table 1 to prepare a curable resin solution.

[0067] (Preparation of cover layer 4) A hard vinyl chloride sheet (product name "Mataeron (registered trademark) product number CB-N-MO", manufactured by Matanaga Chemical Industry Co., Ltd., vinyl chloride resin content 88%) was prepared as the cover layer 4. The thickness of the sheet was 150 μm and the mass was 210 g / m 2 Then, one surface of the sheet was subjected to a corona treatment. Two sheets were prepared.

[0068] (Manufacturing of transparent sheet 1) The prepared curable resin solution for the resin layer 3 was applied to the corona-treated surface of one of the sheets for the cover layer 4. Next, the prepared glass fiber cloth 2 was placed on top of the curable resin solution and left to stand for 1 minute, allowing the curable resin solution to penetrate into the gaps in the glass fiber cloth 2. Next, another sheet for the cover layer 4 was placed on top of it with the corona-treated surface facing the curable resin solution, and a roller was used to roll the sheet for the cover layer 4 until the mass of the resin layer 3 reached 50 g / m. 2 Thereafter, the curable resin solution for the resin layer 3 was irradiated with light using a black light fluorescent lamp (product name FL15BLB, manufactured by Toshiba Corporation) through the sheet for the cover layer 4 (light irradiation conditions: cumulative light amount 200 mJ / cm 2) and curing the curable resin solution to form a resin layer 3, thereby obtaining a transparent sheet 1 of the present invention having a laminated structure of cover layer 4 / resin layer 3 contained in a state of being impregnated in glass fiber cloth 2 / cover layer 4. In the obtained transparent sheet, the resin layer 3 (cured product of the curable resin) was impregnated into the gaps between the glass fibers of the glass fiber cloth, and the resin layer 3 was formed on both sides of the glass fiber cloth layer.

[0069] [Example 4] (Preparation of fiberglass cloth 2) The same glass fiber cloth 2 as in Example 1 was prepared.

[0070] (Preparation of curable resin solution used to form resin layer 3) The same curable resin solution as in Example 3 was prepared.

[0071] (Preparation of cover layer 4) A hard vinyl chloride sheet (product name "Mataeron (registered trademark) product number CB-N-MO", manufactured by Matanaga Chemical Industry Co., Ltd., vinyl chloride resin content 88%) was prepared as the cover layer 4. The thickness of the sheet was 150 μm and the mass was 210 g / m 2 One sheet was prepared, and one surface of the sheet was subjected to a corona treatment.

[0072] (Preparing the process sheet) A hard vinyl chloride sheet (product name "Mataeron (registered trademark) product number CB-N-MO", manufactured by Matanaga Chemical Industry Co., Ltd., vinyl chloride resin content 88%) was prepared as a process sheet. The thickness of the sheet was 150 μm and the mass was 210 g / m 2 It was.

[0073] (Manufacturing of transparent sheet 1) The prepared curable resin solution for the resin layer 3 was applied to the corona-treated surface of one of the sheets for the cover layer 4. Next, the prepared glass fiber cloth 2 was placed on the curable resin solution and left to stand for 1 minute to impregnate the gaps in the glass fiber cloth 2 with the curable resin solution. Next, the process sheet was placed on the curable resin solution, and a roller was used to roll the process sheet from above until the mass of the resin layer 3 reached 50 g / m.2 Thereafter, the curable resin solution to be used as the resin layer 3 was irradiated with light using a black light fluorescent lamp (product name: FL15BLB, manufactured by Toshiba Corporation) (light irradiation conditions: cumulative light amount 200 mJ / cm 2 ) to cure the curable resin solution, forming a resin layer 3, and the process sheet was peeled off to obtain a transparent sheet 1 of the present invention, which has a laminated structure of a cover layer 4 and the resin layer 3 contained in an impregnated state in the glass fiber cloth 2. In the obtained transparent sheet, the resin layer 3 (a cured product of the curable resin) was impregnated into the gaps between the glass fibers of the glass fiber cloth, and the resin layer 3 was formed on both sides of the glass fiber cloth layer.

[0074] [Comparative Example 1] (Preparation of fiberglass cloth 2) The same glass fiber cloth 2 as in Example 1 was prepared.

[0075] (Preparation of curable resin solution used to form resin layer 3) The same curable resin solution as in Example 1 was prepared.

[0076] (Preparation of cover layer 4) A soft vinyl chloride sheet containing 73% by mass of vinyl chloride resin was prepared as the cover layer 4. The thickness of the sheet was 120 μm and the mass was 156 g / m 2 Two sheets were prepared.

[0077] (Manufacturing of transparent sheet 1) The prepared curable resin solution for the resin layer 3 was applied to one side of one sheet that would become the cover layer 4. Next, the prepared glass fiber cloth 2 was placed on the curable resin solution and left to stand for 1 minute, allowing the curable resin solution to be impregnated into the gaps in the glass fiber cloth 2. Next, the sheet that would become the cover layer 4 was placed on the curable resin solution, and a roller was used to roll the sheet that would become the cover layer 4 so that the mass of the resin layer 3 was 50 g / m 2Thereafter, the curable resin solution for the resin layer 3 was irradiated with light using a black light fluorescent lamp (product name FL15BLB, manufactured by Toshiba Corporation) through the sheet for the cover layer 4 (light irradiation conditions: cumulative light amount 200 mJ / cm 2 ) and curing the curable resin solution to form a resin layer 3, thereby obtaining a comparative transparent sheet 1 having a laminated structure of cover layer 4 / resin layer 3 contained in a state of being impregnated into glass fiber cloth 2 / cover layer 4. In the obtained transparent sheet, the resin layer 3 (cured product of the curable resin) was impregnated into the gaps between the glass fibers of the glass fiber cloth, and the resin layer 3 was formed on both sides of the glass fiber cloth layer.

[0078] Comparative Example 2 (Preparation of fiberglass cloth 2) The same glass fiber cloth 2 as in Example 1 was prepared.

[0079] (Preparation of curable resin solution used to form resin layer 3) The same curable resin solution as in Example 1 was prepared.

[0080] (Preparation of cover layer 4) A soft vinyl chloride sheet containing 73% by mass of vinyl chloride resin was prepared as the cover layer 4. The thickness of the sheet was 120 μm and the mass was 156 g / m 2 It was.

[0081] (Preparing the process sheet) A hard vinyl chloride sheet (product name "Mataeron (registered trademark) product number CB-N-MO", manufactured by Matanaga Chemical Industry Co., Ltd., vinyl chloride resin content 88%) was prepared as a process sheet. The thickness of the sheet was 150 μm and the mass was 210 g / m 2 It was.

[0082] (Manufacturing of transparent sheet 1) The curable resin solution prepared for the resin layer 3 was applied to one side of one of the sheets to be used as the cover layer 4. Next, the prepared glass fiber cloth 2 was placed on the curable resin solution and left to stand for 1 minute, allowing the curable resin solution to be impregnated into the gaps in the glass fiber cloth 2. Next, the process sheet was placed on the curable resin solution, and a roller was used to roll the process sheet from above until the mass of the resin layer 3 reached 50 g / m. 2 Thereafter, the curable resin solution to be used as the resin layer 3 was irradiated with light using a black light fluorescent lamp (product name: FL15BLB, manufactured by Toshiba Corporation) (light irradiation conditions: cumulative light amount 200 mJ / cm 2 ) to cure the curable resin solution to form a resin layer 3, and the process sheet was peeled off to obtain a comparative transparent sheet 1 having a laminated structure of a cover layer 4 / the resin layer 3 contained in an impregnated state in the glass fiber cloth 2. In the obtained transparent sheet, the resin layer 3 (a cured product of the curable resin) was impregnated into the gaps between the glass fibers of the glass fiber cloth, and the resin layer 3 was formed on both sides of the glass fiber cloth layer.

[0083] Comparative Example 3 (Preparation of fiberglass cloth 2) The same glass fiber cloth 2 as in Example 1 was prepared.

[0084] (Preparation of curable resin solution used to form resin layer 3) The same curable resin solution as in Example 3 was prepared.

[0085] (Preparation of cover layer 4) A soft vinyl chloride sheet containing 73% by mass of vinyl chloride resin was prepared as the cover layer 4. The thickness of the sheet was 120 μm and the mass was 156 g / m 2 Two sheets were prepared.

[0086] (Manufacturing of transparent sheet 1) The prepared curable resin solution for the resin layer 3 was applied to one side of one sheet that would become the cover layer 4. Next, the prepared glass fiber cloth 2 was placed on the curable resin solution and left to stand for 1 minute, allowing the curable resin solution to be impregnated into the gaps in the glass fiber cloth 2. Next, the sheet that would become the cover layer 4 was placed on the curable resin solution, and a roller was used to roll the sheet that would become the cover layer 4 so that the mass of the resin layer 3 was 50 g / m 2 Thereafter, the curable resin solution for the resin layer 3 was irradiated with light using a black light fluorescent lamp (product name FL15BLB, manufactured by Toshiba Corporation) through the sheet for the cover layer 4 (light irradiation conditions: cumulative light amount 200 mJ / cm 2 ) and curing the curable resin solution to form a resin layer 3, thereby obtaining a comparative transparent sheet 1 having a laminated structure of cover layer 4 / resin layer 3 contained in a state of being impregnated into glass fiber cloth 2 / cover layer 4. In the obtained transparent sheet, the resin layer 3 (cured product of the curable resin) was impregnated into the gaps between the glass fibers of the glass fiber cloth, and the resin layer 3 was formed on both sides of the glass fiber cloth layer.

[0087] Comparative Example 4 (Preparation of fiberglass cloth 2) The same glass fiber cloth 2 as in Example 1 was prepared.

[0088] (Preparation of curable resin solution used to form resin layer 3) The same curable resin solution as in Example 3 was prepared.

[0089] (Preparation of cover layer 4) A soft vinyl chloride sheet containing 73% by mass of vinyl chloride resin was prepared as the cover layer 4. The thickness of the sheet was 120 μm and the mass was 156 g / m 2 It was.

[0090] (Preparing the process sheet) A hard vinyl chloride sheet (product name "Mataeron (registered trademark) product number CB-N-MO", manufactured by Matanaga Chemical Industry Co., Ltd., vinyl chloride resin content 88%) was prepared as a process sheet. The thickness of the sheet was 150 μm and the mass was 210 g / m 2 It was.

[0091] (Manufacturing of transparent sheet 1) The curable resin solution prepared for the resin layer 3 was applied to one side of one of the sheets to be used as the cover layer 4. Next, the prepared glass fiber cloth 2 was placed on the curable resin solution and left to stand for 1 minute, allowing the curable resin solution to be impregnated into the gaps in the glass fiber cloth 2. Next, the process sheet was placed on the curable resin solution, and a roller was used to roll the process sheet from above until the mass of the resin layer 3 reached 50 g / m. 2 Thereafter, the curable resin solution to be used as the resin layer 3 was irradiated with light using a black light fluorescent lamp (product name: FL15BLB, manufactured by Toshiba Corporation) (light irradiation conditions: cumulative light amount 200 mJ / cm 2 ) to cure the curable resin solution to form a resin layer 3, and the process sheet was peeled off to obtain a comparative transparent sheet 1 having a laminated structure of a cover layer 4 / the resin layer 3 contained in an impregnated state in the glass fiber cloth 2. In the obtained transparent sheet, the resin layer 3 (a cured product of the curable resin) was impregnated into the gaps between the glass fibers of the glass fiber cloth, and the resin layer 3 was formed on both sides of the glass fiber cloth layer.

[0092] Comparative Example 5 (Preparation of fiberglass cloth 2) The same glass fiber cloth 2 as in Example 1 was prepared.

[0093] (Preparation of curable resin solution used to form resin layer 3) The same curable resin solution as in Example 3 was prepared.

[0094] (Preparing the process sheet) A hard vinyl chloride sheet (product name "Mataeron (registered trademark) product number CB-N-MO", manufactured by Matanaga Chemical Industry Co., Ltd., vinyl chloride resin content 88%) was prepared as a process sheet. The thickness of the sheet was 150 μm and the mass was 210 g / m 2 Two sheets of the process were prepared.

[0095] (Manufacturing of transparent sheet 1) The prepared curable resin solution for the resin layer 3 was applied to one side of one of the process sheets. Next, the prepared glass fiber cloth 2 was placed on the curable resin solution and left to stand for 1 minute to impregnate the gaps in the glass fiber cloth 2 with the curable resin solution. Next, another process sheet was placed on the curable resin solution, and a roller was used to roll the sheet on top of the curable resin solution until the mass of the resin layer 3 was 50 g / m. 2 Thereafter, the curable resin solution to be used as the resin layer 3 was irradiated with light using a black light fluorescent lamp (product name: FL15BLB, manufactured by Toshiba Corporation) (light irradiation conditions: cumulative light amount 200 mJ / cm 2 ) to cure the curable resin solution to form a resin layer 3, and the two process sheets were peeled off to obtain a comparative transparent sheet 1 consisting only of the resin layer 3 contained in an impregnated state in the glass fiber cloth 2. In the obtained transparent sheet, the resin layer 3 (cured product of the curable resin) was impregnated into the gaps between the glass fibers of the glass fiber cloth, and the resin layer 3 was formed on both sides of the glass fiber cloth layer.

[0096] 3.Results The results are shown in Table 1.

[0097] [Table 1]

[0098] The sheets of Examples 1 to 4 were transparent sheets comprising a glass fiber cloth, a resin layer impregnated into the glass fiber cloth, and a cover layer laminated on at least one side of the resin layer, and the cover layer contained vinyl chloride resin and had a chlorine concentration of 40% or more. The transparent sheet had a total light transmittance of 80% or more and a haze of 30% or less, and therefore the sheet was less likely to spread fire when it came into contact with flames.

Claims

[Claim 1] A transparent sheet comprising a glass fiber cloth, a resin layer impregnated in the glass fiber cloth, and a cover layer laminated on at least one surface of the resin layer, the cover layer contains a vinyl chloride resin and has a chlorine concentration of 40% or more; The transparent sheet has a total light transmittance of 80% or more and a haze of 30% or less.

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