JP7421785B2 - transparent sheet - Google Patents

Description

The present invention relates to a transparent sheet, and specifically to a transparent sheet suitable for smoke-proof hanging walls, etc., and a smoke-proof hanging wall using the transparent sheet.

The Building Standards Act and the Building Standards Act Enforcement Order stipulate that smoke exhaust equipment must be installed to prevent the flow of smoke, toxic gas, etc. generated in the event of a building fire, and to facilitate evacuation and firefighting operations. There is. Therefore, in buildings such as office buildings and commercial facilities, smoke-proof hanging walls are often installed as smoke exhaust equipment and smoke-blocking equipment.

Smoke-proof hanging walls are usually installed in buildings for the purpose of temporarily blocking smoke, toxic gas, etc. from flowing into hallways and upper floors in the event of a fire, and securing the time necessary for evacuation. It is attached to the ceiling. For this reason, in order to prevent smoke-proof hanging walls from obstructing the field of view or spoiling the aesthetics, transparent plate glass, transparent resin composites of glass fiber and resin, etc. are used as smoke-proof hanging walls. A transparent resin composite of glass fiber and resin has the advantage that it is less likely to break than transparent plate glass. For example, Patent Document 1 discloses a transparent noncombustible sheet containing a glass fiber fabric and a cured resin layer.

Further, Patent Document 2 discloses a nonflammable sheet having at least one glass fiber fabric and a photocurable resin impregnated into the glass fiber fabric, the glass fibers in the glass fiber fabric comprising The difference in refractive index between the glass composition and the photocurable resin is 0.02 or less, the ratio of the glass fiber fabric to the nonflammable sheet is 20 to 70% by weight, and the photocurable resin is based on the nonflammable sheet. A nonflammable sheet is disclosed in which the proportion of the resin is 80 to 30% by weight, and the photocurable resin is obtained by curing a composition containing at least brominated vinyl ester.

Japanese Patent Application Publication No. 2005-319746 Japanese Patent Application Publication No. 2014-213489

The Building Standards Act requires smoke-proof hanging walls to be constructed of noncombustible materials. The requirements for the certification test for non-combustible materials include that in the prescribed exothermic test, the total calorific value for 20 minutes after the start of heating is 8 MJ/ ^m2 or less, and that the maximum heat generation rate continues for 10 seconds or more during the 20 minutes after the start of heating. This includes not exceeding 200kw/ ^m2 . The above-mentioned total calorific value tends to increase as the amount of resin (g/m ² ) contained in the sheet increases.

For example, in Patent Document 1, a sheet with a resin content of 300 g/ ^m2 is disclosed as Example 2, but the total calorific value is 8.74 MJ/ ^m2 , which meets the requirements of the qualification test for noncombustible materials. Not satisfied.

On the other hand, in Patent Document 2, a photocurable resin obtained by curing a composition containing brominated vinyl ester is used as a photocurable resin impregnated into a glass fiber fabric, so that the resin weight is 200 g/m ² or more. This is said to solve the problem of not being able to obtain nonflammability certification. As specific examples, Example 1 had a resin weight of 380±10 g/ ^m2 , Example 2 had a resin weight of 260±7 g/ ^m2 , and Example ³ had a resin weight of 140±5 g/m2. It is disclosed that the total calorific value was 5.0 MJ/m ² , 3.0 MJ/m ² , and 2.0 MJ/m ² , respectively. However, in this document, there is a problem in that a range in which the resin weight is 400 g/m ² or more is considered to be a range in which nonflammability certification has not been obtained.

In addition, the present inventors have discovered that in the sheet of Patent Document 2, when the resin weight is increased from Example 3 to Example 2 to Example 1, glass is added at the same time to reduce the total calorific value. We learned that it is necessary to increase the weight of fiber fabrics. In fact, in Patent Document 2, the weight of the glass fiber fabric is 50 g/m ² in Example 3, 100 g/m ² in Example 2, and 150 g/m ² in Example 1, and as the resin weight increases, The weight of the glass fiber fabric has also been increased, and it has been learned that this allows the total calorific value to be set to 8 MJ/m ² or less. The inventors of the present invention have found that as the weight of the glass fiber fabric increases, the haze of the resulting sheet increases, resulting in a decrease in the transparency of the sheet. Therefore, the invention disclosed in Patent Document 2 is still insufficient in achieving both of improving the transparency of the sheet and reducing the total calorific value when the weight of the resin is increased. There's a problem.

Therefore, the present invention solves the above problems and achieves both improved transparency and lower total calorific value when the resin weight is increased in a sheet containing glass fiber fabric and resin. It is an object of the present invention to provide a transparent sheet and a smoke-proof hanging wall using the transparent sheet, which makes it possible to further achieve the following.

In order to solve the above problem, the present inventors studied the invention of Patent Document 2 in more detail. In the invention disclosed in Patent Document 2, a glass fiber fabric is impregnated with brominated vinyl ester to form a photocurable resin, and transparency is achieved by reducing the difference in refractive index between the glass fiber fabric and the photocurable resin. I'm trying. However, in the invention of Patent Document 2, in order to reduce the refractive index difference, the content of brominated vinyl ester in the photocurable resin is limited, and it is necessary to contain components other than brominated vinyl ester. It has been found that when the weight of the resin is increased, it is still insufficient to simultaneously improve the transparency of the sheet and reduce the total calorific value. That is, in resins such as brominated vinyl esters in which a halogen element is a substituent, the halogen element is a high refractive index substituent, so the refractive index of the resin is considerably higher than the refractive index of the glass fiber fabric. . In the invention of Patent Document 2, in order to match the refractive index of the resin impregnated in the glass fiber fabric with the refractive index of the glass fiber fabric, the bromine concentration is lower than that of the glass fiber fabric. I learned that it is necessary to mix with other ingredients. In fact, in the example of Patent Document 2, the refractive index is adjusted to match that of glass fiber fabric by diluting brominated vinyl ester with styrene, neopentyl glycol, etc., but the bromine concentration is lowered. ing. Therefore, the present inventors found that the content of brominated vinyl ester in the sheet of Patent Document 2 was limited, and the low heat generation properties of brominated vinyl ester could not be fully utilized, and when the weight of the resin was increased. At the same time, the weight of the glass fiber fabric must be increased, and it has been found that it is still insufficient to simultaneously improve the transparency of the sheet and reduce the total calorific value.

Therefore, after further study by the present inventors, Patent Document 2 states that since it is essential to use brominated vinyl ester as a resin to be impregnated into glass fiber fabric, it is necessary to match the refractive index of the glass fiber fabric. It was found that the concentration of bromine, which is a high refractive index substituent, must be diluted to limit the content of brominated vinyl ester. In addition to the resin composition layer impregnated in the glass fiber fabric, the present inventors separately laminated a resin composition layer included in the glass fiber fabric in an unimpregnated state, If a resin containing a bromine atom as a substituent such as brominated vinyl ester is used as the resin composition layer contained in the unimpregnated state of the glass fiber fabric, it is not necessary to dilute the resin containing the bromine atom as a substituent with another resin. It was discovered that the low heat generation properties of resins containing bromine atoms as substituents can be further utilized. In other words, by using a resin with a low bromine concentration (including resins that do not contain bromine as described later) in the resin composition layer impregnated into the glass fiber fabric, the difference in refractive index with the glass fiber fabric can be reduced. Separately from the resin composition layer that can be easily made small and that is included in the glass fiber fabric in an unimpregnated state, a resin composition layer that is included in the glass fiber fabric in an unimpregnated state is laminated, and the glass fiber By using a resin with a high bromine concentration as the resin composition layer that is included in the unimpregnated state of the fabric, the low heat generation properties of the resin with a high bromine concentration can be fully utilized, and transparency can be improved even when the resin weight is increased. It has been found that it is possible to more appropriately achieve both of improving the heat generation and lowering the total calorific value. The present invention has been completed through further studies based on these findings.

That is, the present invention provides the inventions of the following aspects.
Item 1. A transparent sheet containing a plain-woven glass fiber fabric and a resin, the first resin layer being impregnated in the glass fiber fabric in the thickness direction of the transparent sheet, and the resin layer not being impregnated in the glass fiber fabric. bromine concentration of the second resin layer is higher than the bromine concentration of the first resin layer, the total light transmittance of the transparent sheet is 85% or more, and the haze is 10% or less. A transparent sheet.
Item 2. Radiation measured in accordance with "4.10.2 Heat generation test and evaluation method" in the "Fireproof performance test and evaluation work method manual" (revised version on March 1, 2014) of the Building Materials Testing Center, the general incorporated foundation. Item 2. The transparent sheet according to item 1, which has a total calorific value of 8 MJ/m ² or less in a heat generation test in which the surface of the sheet is irradiated with 50 kW/m ² of radiant heat from an electric heater.
Item 3. Item 3. The transparent sheet according to Item 1 or 2, wherein the first resin layer is laminated on both surfaces of the second resin layer.
Item 4. 4. The transparent sheet according to any one of Items 1 to 3, wherein the total content of resins contained in the first resin layer and the second resin layer is 200 g/m ² or more.
Item 5. Item 5. The transparent sheet according to any one of Items 1 to 4, wherein the total thickness of the first resin layer and the second resin layer is 180 μm or more.
Item 6. 6. The transparent sheet according to any one of items 1 to 5, wherein the second resin layer contains a brominated vinyl ester resin.
Section 7. Item 7. The transparent sheet according to Item 6, wherein the first resin layer contains tetrabromobisphenol A.

According to the transparent sheet of the present invention, in the transparent sheet containing a plain-woven glass fiber fabric and a resin, a first resin layer impregnated in the glass fiber fabric is included in the thickness direction of the transparent sheet; The transparent sheet includes a second resin layer contained in an unimpregnated state in the glass fiber fabric, and the bromine concentration of the second resin layer is higher than the bromine concentration of the first resin layer, and the total light transmittance of the transparent sheet is 85. % or more, and the haze is 10% or less. Therefore, when the weight of the resin is increased, it becomes possible to achieve both of improving transparency and lowering the total calorific value. Therefore, if a smoke-proof hanging wall is made using the transparent sheet, it will be possible to have a thick smoke-proof hanging wall with a large resin weight while having excellent transparency and a low total calorific value. .

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram explaining one aspect of the transparent sheet of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram explaining one aspect of the transparent sheet of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram explaining one aspect of the transparent sheet of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram explaining one aspect of the transparent sheet of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram explaining one aspect of the transparent sheet of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram explaining one aspect of the transparent sheet of this invention. 4.10.2 Regarding the test equipment used when performing the heat generation test and evaluation method in the “Fireproof performance test and evaluation work method manual” (revised version on March 1, 2014) of the Building Materials Testing Center, a general incorporated foundation. It is a figure showing an outline. 4.10.2 Regarding the test equipment used when performing the heat generation test and evaluation method in the “Fireproof performance test and evaluation work method manual” (revised version on March 1, 2014) of the Building Materials Testing Center, a general incorporated foundation. FIG. 2 is a schematic diagram of the included test holder and presser frame. The unit of numerical values (dimensions) shown in FIG. 8 is mm.

The transparent sheet of the present invention is a transparent sheet containing a plain-woven glass fiber fabric and a resin, and includes, in the thickness direction of the transparent sheet, a first resin layer impregnated with the glass fiber fabric; The glass fiber fabric includes a second resin layer that is not impregnated, the second resin layer has a higher bromine concentration than the first resin layer, the transparent sheet has a total light transmittance of 85% or more, and has a haze. is 10% or less.

For example, as shown in FIGS. 1 to 6, the transparent sheet 1 of the present invention includes a glass fiber fabric 2, a first resin layer 3 impregnated in the glass fiber fabric 2, and a first resin layer 3 impregnated in the glass fiber fabric 2. The bromine concentration of the second resin layer 4 is higher than the bromine concentration of the first resin layer 3.

In the transparent sheet 1 of the present invention, at least one glass fiber fabric 2 may be included, and a plurality of glass fiber fabrics 2 may be included. Further, as shown in FIGS. 1 to 6, in the transparent sheet 1 of the present invention, the first resin layer 3 fills the gaps between the glass fibers constituting the glass fiber fabric 2, and the first resin layer One surface side portion of No. 3 and the other surface side portion of No. 3 communicate with each other through the gap. As shown in FIGS. 1, 3, 4, and 6, the transparent sheet 1 of the present invention includes a plurality of first resin layers 3 impregnated with a glass fiber fabric 2. Can be done. Although not shown in FIGS. 1 to 6, one first resin layer 3 may include a plurality of glass fiber fabrics 2.

In the transparent sheet 1 of the present invention, the second resin layer 4 included in the glass fibers without being impregnated may be one layer as shown in FIGS. 1 and 4, for example, or may be a single layer as shown in FIGS. As shown in FIGS. 5 and 6, there may be multiple layers. When the second resin layer 4 has multiple layers, it is preferably 2 to 5 layers, more preferably 2 to 3 layers.

For example, the transparent sheet 1 shown in FIGS. 1, 3, 4, and 6 has a laminated structure in which the first resin layer 3 is laminated on both surfaces of the second resin layer 4, respectively. Further, the transparent sheets 1 shown in FIGS. 2, 3, 5, and 6 have a laminated structure in which second resin layers 4 are laminated on both surfaces of the first resin layer 3, respectively. In the transparent sheet 1 of the present invention, as a specific example of the laminated structure of the first resin layer 3 and the second resin layer 4, first resin layer 3/second resin layer 4/first resin layer 4 as shown in FIGS. A laminated structure in which the first resin layer 3 is laminated in this order; a laminated structure in which the second resin layer 4/first resin layer 3/second resin layer 4 is laminated in this order as shown in FIGS. 2 and 5; and a laminated structure in which second resin layer 4/first resin layer 3/second resin layer 4/first resin layer 3/second resin layer 4 are laminated in this order as shown in FIG.

In the transparent sheet 1 of the present invention, layers other than the first resin layer 3 and the second resin layer 4 may be provided. For example, as shown in FIGS. 4 to 6, the transparent sheet 1 of the present invention may include a film layer 5. It is preferable that one film layer 5 is included on the outside of the first resin layer 3 and the second resin layer 4. Although not shown, the transparent sheet 1 of the present invention may be provided with a cover layer that is peeled off when used as a smoke-proof hanging wall, for example. Each layer constituting the transparent sheet 1 of the present invention will be described in detail below.

[Glass fiber fabric 2]
In the transparent sheet 1 of the present invention, the glass fiber fabric 2 is impregnated with a first resin layer 3, which will be described later. In the transparent sheet 1 of the present invention, the glass fiber fabric 2 contributes to improving the nonflammability of the sheet. The refractive index of the glass fiber fabric 2 is set to be similar to the refractive index of the first resin layer 3, which will be described later. It is possible to configure the ratio to be 10% or less. In other words, the configuration in which the transparent sheet 1 of the present invention has a total light transmittance of 85% or more and a haze of 10% or less means that at least the refractive index of the glass fiber fabric 2 and the refractive index of the first resin layer 3 described later are are sufficiently approximated (for example, the difference between the refractive index of the glass fiber fabric 2 and the refractive index of the first resin layer 3 is 0.02 or less).

In the transparent sheet 1 of the present invention, the glass fiber fabric 2 has a plain weave structure made of a plurality of glass fibers. In the glass fiber fabric 2, a plurality of glass fibers are intertwined with each other to form one cloth.

The glass material of the glass fibers constituting the glass fiber fabric 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-modulus glass (S glass, T glass, etc.), alkali-resistant glass (AR glass), etc. Preferably, highly versatile alkali-free glass (E glass) is used. The glass fibers constituting the glass fiber fabric 2 may be made of one type of glass material, or may be a combination of two or more types of glass fibers made of different glass materials. Moreover, from the viewpoint of improving transparency, it is preferable to select a glass material having a refractive index similar to that of the first resin layer 3, which will be described later.

The count of the glass fibers constituting the glass fiber fabric 2 is not limited to a specific one as long as the glass fiber fabric 2 can be formed. From the viewpoint of further improving transparency, the glass fiber count is preferably 20 tex or less, preferably 3 to 6 tex, and more preferably 3 to 5 tex. The number of glass fibers may be one type or a combination of two or more types. Note that the tex count of glass fiber corresponds to the number of grams per 1000 m.

The glass fibers constituting the glass fiber fabric 2 are preferably glass yarns in which a plurality of single fibers, which are long glass fibers, are twisted together. The number of single fibers in the glass yarn is preferably about 30 to 400, more preferably about 40 to 120. Further, the diameter of the single fibers in the glass yarn is preferably about 3.0 to 6.0 μm, more preferably about 3.0 to 5.0 μm, from the viewpoint of further improving the transparency of the transparent sheet 1. The count of the glass yarn is preferably 2 to 30 tex, more preferably 2 to 12 tex, and even more preferably 2 to 5 tex, from the viewpoint of further improving the transparency of the transparent sheet 1 while improving the nonflammability of the transparent sheet 1.

In the transparent sheet 1, the total amount (g/m ² ) of the total mass (g/m 2 ) of the glass fiber fabric 2 and the total mass (g/m ² , excluding the glass fiber fabric 2) of the first resin layer 3 (described later). The ratio (mass%) of the total mass of the glass fiber fabric 2 in the transparent sheet 1 to the total weight of the glass fiber fabric ² in the transparent sheet 1 is determined to improve transparency and reduce the total calorific value when the weight of the resin in the transparent sheet is increased. From the viewpoint of further achieving compatibility with the product, the amount is preferably 20 to 60% by mass, and more preferably 30 to 60% by mass. Furthermore, the total mass (g/m ² ) of the glass fiber fabric 2 in the transparent sheet 1 is relative to the total mass (g/m 2 ) of the transparent sheet 1 excluding the cover layer that is peeled off when used as a smoke-proof hanging wall, which will be described ^later. ) is preferably 5 to 50 mass %, and 5 to 28 mass %, from the viewpoint of further achieving both improved transparency and lower total calorific value. is more preferable, 5 to 25% by weight is even more preferable, and 8 to 19% by weight is particularly preferable. The mass (g/m ² ) of each glass fiber fabric 2 is preferably 10 to 120 (g/m ² ), more preferably 10 to 60 (g/m ² ), and more preferably 20 to 40 (g/m 2 ). ² ) is more preferred. In addition, the total mass (g/m ² ) of the glass fiber fabric 2 in the transparent sheet 1 is 10 to 120 (g/m 2 ) from the viewpoint of further improving the transparency of the transparent sheet 1 while improving the nonflammability of the transparent sheet 1. g/m ² ), more preferably 20 to 100 (g/m ² ), particularly preferably 30 to 80 (g/m ² ).

The difference in refractive index between the glass fiber fabric 2 and the first resin layer 3 described below is preferably 0.02 or less, more preferably 0.01 or less. The refractive index of the glass fiber fabric 2 is preferably about 1.50 to 1.58, more preferably about 1.53 to 1.57.

The refractive index of the glass fiber fabric 2 is measured in accordance with method B of JIS K 7142:2008. Specifically, first, the glass fibers constituting the glass fiber fabric are crushed to such an extent that Becke lines can be observed when observed using an optical microscope at a magnification of 400 times. Using a halogen lamp equipped with an interference filter for D-rays as a light source, the refraction was observed and measured using an optical microscope at a magnification of 400 times and a temperature of 23°C, and the average value of the three tests was taken. Let be the value of the rate. Moreover, the measurement of the refractive index of the first resin layer 3 and the second resin layer 4 is performed according to method B of JIS K 7142:2008. Specifically, the first resin layer 3 or the second resin layer 4 is crushed to such an extent that Becke lines can be observed when observed using an optical microscope at a magnification of 400 times. Using a halogen lamp equipped with an interference filter for D-rays as a light source, the refraction was observed and measured using an optical microscope at a magnification of 400 times and a temperature of 23°C, and the average value of the three tests was taken. Let be the value of the rate.

The difference in Abbe number between the glass fiber fabric 2 and the first 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 fabric 2 is preferably 30 to 80, more preferably 40 to 70, even more preferably 50 to 65. Note that the Abbe numbers of the first resin layer 3 and the glass fiber fabric 2 are each measured as follows.

(Abbe number of first resin layer 3)
Using the resin constituting the first resin layer 3, a sheet that does not contain the glass fiber fabric 2 was produced with a width of 8 mm, a length of 20 mm, and a thickness of 0.2±0.1 mm, and was processed according to JIS K 7142A method. Similarly, the refractive index at a wavelength of 589 nm is measured at a measurement temperature of 23° C. using NAR-2T manufactured by Atago Co., Ltd. as an Abbe refractometer, diiodomethane as a contact liquid, and sodium D line with a wavelength of 589 nm as a light source. Subsequently, the dispersion value is measured and calculated using natural light as a light source, and the Abbe number is calculated according to the following formula (I).
Abbe number = (refractive index at wavelength 589 nm - 1) / dispersion value (I)

(Abbe number of glass fiber fabric 2)
A glass sheet with a width of 8 mm, a length of 20 mm, and a thickness of 5 ± 1 mm was prepared using the glass material constituting the glass fibers, the surface was well polished, and it was manufactured by Atago Co., Ltd. as an Abbe refractometer according to the JIS K 7142A method. The refractive index at a wavelength of 589 nm is measured at a measurement temperature of 23° C. using NAR-2T manufactured by NAR-2T, diiodomethane as a contact liquid, and a sodium D line with a wavelength of 589 nm as a light source. Subsequently, the dispersion value is measured and calculated using natural light as a light source, and the Abbe number is calculated according to the above formula (I).

The thickness per sheet of the glass fiber fabric 2 is, for example, about 10 to 100 μm, from the viewpoint of further improving the transparency of the transparent sheet 1 while improving the nonflammability of the transparent sheet 1, and 10 to 55 μm. is preferred, and about 10 to 35 μm is more preferred. When the thickness of the glass fiber fabric 2 is 10 to 35 μm, it is particularly preferable that the glass volume fraction of the glass fiber fabric 2 calculated by the following formula (II) is 38% or more. The glass fiber fabric 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 a glass fiber fabric to an opening treatment.

Glass volume ratio (%) = (A/(B x C)) x 100 (II)
A: Mass of glass fiber fabric (g/m ² )
B: Specific gravity of the glass material constituting the glass fiber fabric (g/m ³ )
C: Thickness of glass fiber fabric (m)

(First resin layer 3)
In the transparent sheet 1 of the present invention, the first resin layer 3 is impregnated into the glass fiber fabric 2, and is formed by curing or solidifying a resin composition containing a resin. Further, as described below, the second resin layer 4 is included in the glass fiber fabric in an unimpregnated state. Therefore, at least when the first resin layer 3 and the second resin layer 4 are in contact with each other, the glass fiber fabric 2 is not exposed on the surface of the first resin layer 3, and the glass fiber fabric 2 is contained in the first resin layer 3. As mentioned above, the first resin layer 3 is selected and set so as to approximate the refractive index of the glass fiber fabric 2, thereby reducing light scattering on the glass fiber surface and achieving a total light transmittance of 85%, which will be described later. As described above, a structure with a haze of 10% or less can be achieved.

The first resin layer 3 can be a cured resin layer or a thermoplastic resin layer. In the case of a cured resin layer, a cured product obtained by applying energy such as light or heat to a resin composition containing a curable resin (a photocured resin composition or a thermocured resin composition) resin composition). When setting it as a thermoplastic resin layer, it can be set as the hardened|cured material obtained by drying and solidifying a thermoplastic resin composition.

In the transparent sheet 1 of the present invention, it is necessary that the bromine concentration of the second resin layer 4 described later is higher than the bromine concentration of the first resin layer 3. That is, the present inventors have found that when the bromine concentration in the resin impregnated into the glass fiber fabric increases, the calorific value of the resin decreases, but the refractive index of the resin becomes higher than the refractive index of the glass fiber fabric. It has been learned that the transparency of the resulting sheet is likely to be impaired. Therefore, by using a resin with a lower bromine concentration for the first resin layer 3 impregnated in the glass fiber fabric, the difference in refractive index with the glass fiber fabric 2 can be easily reduced, and , a second resin layer 4 included in the glass fiber fabric 2 in an unimpregnated state is laminated separately from the first resin layer 3 included in the glass fiber fabric in an impregnated state, and the second resin layer 4 is laminated in an unimpregnated state in the glass fiber fabric 2. By using a resin with a higher bromine concentration as the second resin layer 4 included, the low heat generation property of the resin with a high bromine concentration can be fully utilized, and transparency can be improved when the resin weight is increased. They have discovered that it is possible to achieve both of this and lowering the total calorific value.

From the viewpoint of further lowering the haze of the transparent sheet 1 of the present invention, the bromine concentration in the first resin layer 3 is, for example, 30% by mass or less, preferably 26% by mass or less, More preferably, the content is 20% by mass or less, and even more preferably 16.7% by mass or less. The lower limit of the bromine concentration in the first resin layer 3 is 0% by mass. That is, the first resin layer 3 does not need to contain bromine.

In the present invention, the bromine concentration is measured by EDS analysis. Specifically, the cut surface of the transparent sheet 1 in the thickness direction as illustrated in FIGS. Using a sample with a thickness of 1 cm as the measurement sample, use a JEOL Ltd. product name JSM-6390A to measure one arbitrary point near the center of the layer to be measured in the thickness direction, and calculate the value. Let the bromine concentration be in each layer.

In the transparent sheet 1 of the present invention, the difference between the bromine concentration (mass%) of the first resin layer 3 and the bromine concentration (mass%) of the second resin layer 4 (=bromine concentration of the second resin layer 4 - For example, the bromine concentration in the resin layer 3 is 3% by mass or more, which further improves the balance between improving transparency and lowering the total calorific value when the resin weight is increased. From the viewpoint of the desired performance, 5 to 50% by mass is preferred, 10 to 40% by mass is more preferred, and 20 to 30% by mass is particularly preferred.

From the viewpoint of further improving the transparency of the transparent sheet 1, the curable resin used for forming the first resin layer 3 should have a refractive index similar to that of the first resin layer 3 and the glass fiber fabric 2 described above. Preferably one that can. The curable resin is preferably one in which the curable resin composition is photocurable, such as vinyl ester resin, urethane acrylate resin, fluorene acrylate resin, unsaturated polyester resin, curable acrylic resin, epoxy resin, etc. It will be done. Among these, in the case of providing the film layer 5, from the viewpoint of further improving the adhesiveness with the film layer 5, a curable acrylic resin is more preferable, and a cured resin composition containing acrylic syrup is particularly preferable. In the present invention, acrylic syrup refers to a polymerizable liquid mixture in which a (meth)acrylic acid ester polymer such as polymethyl methacrylate (PMMA) is dissolved in an acrylic monomer such as methyl methacrylate. Among the above acrylic syrups, one or more acrylic acid ester polymers selected from the group consisting of polymethyl methacrylate, methyl methacrylate/methyl acrylate copolymer, and methyl methacrylate/n-butyl acrylate copolymer are used as methacrylic syrups. Acrylic syrup dissolved in acid methyl monomer is particularly preferred. In this way, when the first resin layer 3 is made of a cured resin composition containing acrylic syrup, the adhesion with the film layer 5 is further improved, so that the transparency of the transparent sheet 1 is further improved. Therefore, it is preferable.

As the thermoplastic resin used for forming the first resin layer 3, it is possible to approximate the refractive index of the first resin layer 3 and the glass fiber fabric 2 from the viewpoint of further improving the transparency of the transparent sheet 1. Preferably. Preferred thermoplastic resins include, for example, polyvinyl chloride resins, saturated polyester resins, polyolefin resins, thermoplastic acrylic resins, polycarbonate resins, polyvinyl alcohol resins, ethylene vinyl acetate copolymers, polyamide resins, polyarylate resins, and the like. For example, when E glass is used as the glass material for the glass fibers constituting the glass fiber fabric 2, polyvinyl chloride resin, saturated polyester resin, thermoplastic acrylic resin, etc. Resins and the like are preferred. One type of thermoplastic resin may be used alone, or two or more types having different refractive indexes may be used in combination for the purpose of approximating the refractive index of the glass fiber used. In addition, in the transparent sheet 1 of the present invention, when the first resin layer 3 is a thermoplastic resin composition layer, the first resin layer 3 is impregnated with a thermoplastic resin composition in sol form or dissolved in a solvent, solidified ( It is preferable to solidify by heating or solidifying by drying.

The resin composition constituting the first resin layer 3 is specified in the "4.10 .2 In a heat generation test in which 50kW/ ^m2 of radiant heat is irradiated onto the surface of the sheet from a radiant electric heater, the maximum heat generation rate continues for 10 seconds or more within 20 minutes of the start of heating. From the viewpoint of not exceeding 200 kw/m ² , it may contain phosphorus. As for the form of phosphorus content, for example, among the above-mentioned resins, a resin composition consisting of a resin in which a phosphorus atom is introduced as a substituent, or a resin composition in which a known phosphorus-based flame retardant is added to the above-mentioned resin may be used. Can be done. Examples of phosphorus-based flame retardants include those containing condensed phosphate ester compounds such as non-halogen condensed phosphate ester compounds and halogen-containing condensed phosphate ester compounds. It is more preferable that a phosphoric acid ester compound is included. Moreover, from the viewpoint of further suppressing the bleed-out of the phosphoric ester compound, it is more preferable that a condensed phosphoric ester compound having a molecular weight of 420 or more is included. Examples of non-halogen condensed phosphate ester compounds include 1,3-phenylene bis(diphenyl phosphate) [RDP, molecular weight 574.46], bisphenol A bis(diphenyl phosphate) [BDP, molecular weight 692.64], 1,3- Examples include phenylene bis(dixylenyl) phosphate [molecular weight 686.67], bisphenol A bis((bisdimethylphenyl) phosphate) [molecular weight 804.86], and the like. Examples of the halogen-containing condensed phosphoric acid ester compound include 2,2-bis(chloromethyl)trimethylenebis(bis(2chloroethyl)phosphate) [molecular weight: 582.99]. These phosphoric acid ester compounds may be used alone or in combination of two or more.

In addition, the resin composition constituting the first resin layer 3 is specified in the "4. .10.2 In a heat generation test in which the surface of the sheet is irradiated with 50kW/ ^m2 of radiant heat from a radiant electric heater, the maximum heat generation rate is 10 seconds or more within 20 minutes of the start of heating. Tetrabromobisphenol A, decabromodiphenyl ^ether , etc., from the viewpoint of making it even more difficult for cracks and holes that penetrate to the back surface, which are harmful from a fire safety standpoint, to occur for 20 minutes after the start of heating, while not exceeding 200kw/m2 continuously. Or, it is preferable to contain brominated vinyl ester, and it is more preferable to contain tetrabromobisphenol A. Specifically, in particular, when the glass fiber fabric 2 is lightweight, such as having a mass of 40 g/m ² or less, the above-mentioned phosphorus may be added to the first resin layer 3 impregnated in the glass fiber fabric 2. If it is contained, the first resin layer may swell in the heat generation test, and the glass fiber fabric 2 may become easily deformed accordingly. On the other hand, when the first resin layer 3 contains tetrabromobisphenol A, decabromodiphenyl ether, or brominated vinyl ester, the occurrence of the above-mentioned blistering is suppressed, and the cracks and holes that penetrate to the back surface, which are harmful in terms of fire protection, are further reduced. Make it less likely to occur.

Further, the resin composition constituting the first resin layer 3 can contain an inorganic flame retardant such as antimony trioxide and magnesium hydroxide.

Moreover, the resin composition constituting the first resin layer 3 may further contain additives such as a curing accelerator, an ultraviolet absorber, a filler, and a photopolymerization initiator. Examples of the ultraviolet absorber include benzotriazole. Examples of fillers include calcium carbonate, silica, and talc. As a photopolymerization initiator, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propane-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-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]- Examples include 1-butanone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide. Among these, when using a curable acrylic resin as the first resin layer 3, 1-hydroxy-cyclohexyl-phenyl-ketone is preferred from the viewpoint of improving transparency. These additives may be used alone or in combination of two or more. When the first resin layer 3 contains additives, the content thereof is preferably 0.1 to 5% by mass, more preferably 0.1 to 3% by mass.

In the transparent sheet 1 of the present invention, the total mass of the resin composition of the first resin layer 3 (mass excluding the glass fiber fabric 2) is, for example, 20 to 250 g/m ² , and when the resin weight is increased From the viewpoint of further achieving both improved transparency and better nonflammability, 20 to 200 g/m ² is preferred, and 20 to 120 g/m ² is more preferred. 20 to 80 g/m ² is particularly preferred. Further, the thickness per layer of the first resin layer 3 (the thickness including the glass fiber fabric 2) is, for example, 20 to 150 μm, and when the resin weight is increased, transparency is improved. From the viewpoint of further achieving both the above-mentioned properties and superior nonflammability, the thickness is preferably 20 to 100 μm, and more preferably 20 to 50 μm.

In the transparent sheet 1 of the present invention, the refractive index of the first resin layer 3 is preferably about 1.50 to 1.58, more preferably about 1.53 to 1.57.

(Second resin layer 4)
In the transparent sheet 1 of the present invention, the second resin layer 4 is included in the glass fiber fabric 2 in an unimpregnated state. As described above, the bromine concentration in the second resin layer 4 is higher than the bromine concentration in the first resin layer 3. In the transparent sheet 1 of the present invention, a first resin layer 3 included in the glass fiber fabric 2 in an impregnated state, and a second resin layer 4 separately included in the glass fiber fabric 2 in an unimpregnated state. As the second resin layer 4 which is laminated and is contained in the glass fiber fabric 2 without being impregnated, a resin having a relatively high bromine concentration is used. As a result, the transparent sheet 1 of the present invention does not need to be made to approximate the refractive index of the glass fiber fabric 2, such as by diluting it with another resin with a low bromine concentration as in Patent Document 2, and can be made using a resin with a high bromine concentration. You can take full advantage of its low heat generation properties.

The bromine concentration in the second resin layer 4 of the transparent sheet 1 of the present invention is, for example, 31% by mass or more, from the viewpoint of further suppressing the total calorific value and increasing the resin weight. , 35% by mass is preferred. The upper limit is not particularly limited, but may be, for example, 60% by mass or less, or 55% by mass or less.

Examples of methods for incorporating bromine into the second resin layer 4 include a method in which the resin constituting the second resin layer 4 is made into a resin containing bromine atoms as a substituent, a flame retardant containing a bromine atom is added to a curable resin, Examples include a method of adding a resin composition to a thermoplastic resin.

Examples of the resin containing a bromine atom as a substituent include curable resins or thermoplastic resins containing a bromine atom as a substituent. Examples of the curable resin containing a bromine atom as a substituent include brominated epoxy resin, brominated vinyl ester resin, and brominated unsaturated polyester resin. Examples of the thermoplastic resin containing a bromine atom as a substituent include brominated polycarbonate resin, brominated polyurethane resin, and brominated polyester resin.

Examples of the flame retardants containing a bromine atom include decabromodiphenyl, tetrabromobisphenol A (TBBA) and its derivatives, bis(pentabromophenyl)ethane, 1,2-bis(2,4,6-tribromophenoxy) ) Phenyl oxide flame retardants such as ethane, brominated polystyrene, hexabromocyclododecane, hexabromobenzene, pentabromobenzyl acrylate, pentabromobenzyl acrylate, decabromodiphenyl oxide, octabromodiphenyl oxide, and tetrabromodiphenyl oxide, etc. It will be done. Examples of the resin containing the flame retardant include a resin containing a bromine atom as a substituent, and a curable resin or thermoplastic resin as exemplified in the first resin layer 3 above.

In the transparent sheet 1 of the present invention, the total mass of the second resin layer 4 is, for example, 100 to 600 g/m ² , preferably 180 to 500 g/m ² . Further, the thickness per layer of the second resin layer 4 is, for example, 80 to 600 μm, preferably 100 to 400 μm.

In the transparent sheet 1 of the present invention, the refractive index of the second resin layer 4 is not particularly limited, but is, for example, 1.570 to 1.650, more preferably 1.572 to 1.620, and still more preferably 1.570 to 1.650. 580 to 1.620. Moreover, the difference between the refractive index of the glass fiber fabric 2 and the refractive index of the second resin layer 4 includes a difference exceeding 0.01, and a difference exceeding 0.02.

Further, while improving the transparency of the transparent sheet 1 of the present invention and lowering the total calorific value, it is also possible to increase the resin weight of the transparent sheet 1 to improve its mechanical strength. From the viewpoint of effectively increasing the ) and the total in the second resin layer 4) is preferably 200 g/m ² or more, more preferably 240 g/m ² or more, still more preferably 270 g/m ² or more. Note that the upper limit of the total content is, for example, 600 g/m ² or less.

Further, from the same viewpoint, the total thickness of the first resin layer 3 and the second resin layer 4 (the total of all the first resin layers 3 and second resin layers 4 included in the transparent sheet 1) is preferably 180 μm. Above, more preferably 200 μm or more, still more preferably 240 μm or more. In addition, as an upper limit of the said total thickness, 500 micrometers or less and 450 micrometers or less are mentioned, for example.

(Film layer 5)
In the transparent sheet 1 of the present invention, the film layer 5 is laminated on the first resin layer 3 or the second resin layer 4 as necessary, and serves to further improve the initial tear strength of the transparent sheet 1. It is preferable that one film layer 5 is included on the outside of the first resin layer 3 and the second resin layer 4.

The material constituting the film layer 5 is not particularly limited. Examples include polyester resin, polycarbonate resin, polyolefin resin, fluororesin, acrylic resin, and polyamide resin. On the other hand, the film layer 5 preferably contains a thermoplastic resin other than polyvinyl chloride resin. Examples of thermoplastic resins other than polyvinyl chloride resins include those that can be formed into a film even with a small amount of plasticizer, and biaxially oriented thermoplastic resins containing amorphous thermoplastic resins other than polyvinyl chloride resins. Films are preferred. Examples of thermoplastic resins other than polyvinyl chloride resins include polyester resins, polycarbonate resins, fluororesins, acrylic resins, and polyamide resins, and at least one of these resins may be included. Furthermore, the film layer 5 may not contain polyvinyl chloride resin. From the viewpoint of further improving the initial tear strength of the transparent sheet 1, the film layer 5 may have an Elmendorf tear propagation resistance of 1 N/mm or more in both the vertical and horizontal directions. 3 to 20 N/mm is preferred, and 5 to 15 N/mm is more preferred. Among these, from the viewpoint of further achieving both chemical resistance (including alkaline detergent resistance when used as a smoke-proof hanging wall), improvement of initial tear strength, and transparency, the film layer 5 should contain polyester resin. It is preferable that the Examples of the polyester resin include polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). The Elmendorf tear propagation resistance was determined by measuring the tear strength (N) based on JIS K7128-2/1998 using an Elmendorf tearing machine manufactured by Toyo Seiki Seisakusho Co., Ltd., and dividing this measured value by the film thickness. Means tear propagation resistance (N/mm). Furthermore, the tear strength is the average value of the test results of 20 samples in each of the vertical and horizontal directions. Furthermore, if the film layer 5 is made of a resin composition containing PVDF and an acrylic resin (PMMA, etc.), it will have excellent weather resistance and will have good adhesion to the first resin layer 3 and the second resin layer 4. It is excellent and suitable as a membrane material.

In the transparent sheet of the present invention, it is preferable that the film used as the film layer 5 has excellent transparency and smoothness. Regarding the transparency of the film used as the film layer 5, for example, the total light transmittance (JIS K 7105:1981) is preferably 90% or more, more preferably 91 to 98%. Further, for example, the haze (JIS K 7105:1981) is preferably 1.5% or less, more preferably 0.3 to 1.0%.

(Antistatic layer containing metal or metal compound)
The transparent sheet 1 of the present invention can be provided with an antistatic layer containing a metal or a metal compound as the outermost layer when used as a smoke-proof hanging wall, for example.

In the antistatic layer containing a metal or a metal compound, examples of the metal elements included include Ag, Ni, Cu, Sn, Sb, Al, In, Ti, etc., and the standard electrode potential when used as a single metal is Examples include metal elements with a voltage of less than 0 eV. Examples of the metal compound include metal oxides (antimony pentoxide, tin oxide, zinc oxide, indium oxide, antimony-doped indium oxide, tin-doped indium oxide, silver oxide, etc.). Further, the antistatic layer may not contain fine particles made of barium sulfate, calcium carbonate, aluminum oxide, magnesium silicate, glass, or the like. Examples of the form in which the metal or metal compound is contained include a metal or metal compound thin film formed by vapor deposition, sputtering, plating, etc., or a layer in which metal or metal compound fine particles are dispersed in a fixed resin. Examples of the shape of the metal or metal compound fine particles include granules, flakes, and needles (fibers). The average particle diameter of the metal or metal compound fine particles is, for example, the average particle diameter determined using the BET method (calculated as the average particle diameter by a conventional method from the specific surface area (m ² /g) measured by the nitrogen gas adsorption method). The transparency of the transparent sheet 1 can be more easily maintained by setting the specific surface area (diameter) to 100 nm or less, preferably 1 to 100 nm, which is the wavelength of visible light.

When the antistatic layer containing metal or metal compound fine particles contains metal or metal compound fine particles, it preferably contains a fixing resin that fixes the metal or metal compound fine particles to the base material. That is, it is preferable that the antistatic layer is a layer containing a fixed resin and metal or metal compound fine particles dispersed in the fixed resin. Examples of the fixing resin include polyurethane resin, polyester resin, acrylic resin, polyether resin, cellulose resin, polyvinyl alcohol resin, epoxy resin, polyvinylpyrrolidone, polystyrene resin, polyethylene glycol, and pentaerythritol. Among them, polyurethane resins, polyester resins, and acrylic resins are particularly preferred. The acrylic resin may be, for example, a modified acrylic resin (urethane modified, polyester modified, polycarbonate modified, fluorine modified, etc.). The mass of the antistatic layer is, for example, 0.1 to 10 g/m ² per layer, preferably 0.1 to 5 g/m ² , and more preferably 0.1 to 3 g/m ² . 0.1 to 1 g/m ² is particularly preferred. Further, the thickness of the antistatic layer is, for example, 0.01 to 3 μm per layer, preferably 0.05 to 1 μm. In the antistatic layer, the mass ratio of the fixed resin and the metal or metal compound fine particles (mass of the fixed resin (g/m ² ):mass of the metal or metal compound fine particles (g/m ² )) is 10: The ratio is preferably 1 to 1:1, more preferably 8:1 to 2:1, and particularly preferably 4:1 to 2:1. Furthermore, the surface smoothness when an antistatic layer containing a metal or a metal compound is provided includes, for example, a surface roughness Ra of 1 to 200 nm. Further, the ratio of the mass (g/m ² ) of the metal and metal compound fine particles to the total mass (g/m ² ) of the antistatic layer is 50 to 10 mass%, preferably 30 to 20 mass%. Can be mentioned.

(peelable cover layer that is peeled off during use)
The transparent sheet 1 of the present invention may be attached to the first resin layer 3, the second resin layer 4, or the outside of the film layer 5 (the antistatic layer 6 is attached to the first resin layer 3, the second resin layer 4, or the outside of the film layer 5) as necessary. When provided on the outside of the film layer 5, a removable cover layer that is peeled off during use can be further laminated on the outside of the antistatic layer 6. A peelable cover layer can be suitably provided on the outermost surface of the transparent sheet 1 of the present invention. Thereby, for example, when the transparent sheet 1 of the present invention is used as a smoke-proof hanging wall, it becomes easier to prevent scratches and the like from occurring on the transparent sheet 1 during construction and deterioration of transparency and aesthetic appearance.

As the releasable cover layer to be peeled off during use, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, a polyester film, etc. can be used. Among these, if a light-transmitting protective film is used as the peelable cover layer that is peeled off during use, for example, the resin composition forming the first resin layer 3 or the second resin layer 4 described above may be photocurable. When using a curable resin composition, it becomes easier to prevent scratches from occurring on the surface of the outermost layer during use and deterioration of transparency and aesthetic appearance during the curing process of the curable resin composition. This is preferable in this respect. The above-mentioned light transmittance is not particularly limited as long as it transmits light that cures the photocurable resin, but for example, it transmits light with a wavelength of 100 to 400 nm, or transmits light with a wavelength of 250 to 400 nm. Can be mentioned. The light transmittance of the cover layer is preferably 40% or more, with an average transmittance of 50% at a measurement wavelength of 250 to 400 nm, as measured by a UV transmittance meter (product name: UV3150, manufactured by Shimadzu Corporation), for example. It is more preferably 60% or more, and particularly preferably 60% or more.

Note that the peelable cover layer that is peeled off during use is not particularly limited in terms of transparency and smoothness since it is peeled off during use, such as a smoke-proof hanging wall. For example, from the viewpoint of cost, the total light transmittance is about 80 to 95% (JIS K 7105:1981), and the haze is about 2 to 10% (JIS K 7105:1981).

(Physical properties of transparent sheet 1)
The transparent sheet 1 of the present invention has a total light transmittance (total light transmittance after peeling off the cover layer if it includes a peelable cover layer that is peeled off during use) of 85% or more, haze (peeling off during use) When a peelable cover layer is included, the haze after peeling off the cover layer is 10% or less. As mentioned above, the configuration in which the transparent sheet 1 of the present invention has a total light transmittance of 85% or more and a haze of 10% or less is based on at least the refractive index of the glass fiber fabric 2 and the refractive index of the first resin layer 3. are sufficiently approximated (for example, the difference between the refractive index of the glass fiber fabric 2 and the refractive index of the first resin layer 3 is 0.02 or less). The total light transmittance is preferably 90% or more. Further, the haze is preferably 5% or less, more preferably 3% or less, and particularly preferably 1% or less. The total light transmittance of the transparent sheet 1 is a value obtained by measuring according to JIS K7361-1 1997, and the haze is a value obtained by measuring according to JIS K 7136:2000.

The thickness of the transparent sheet 1 of the present invention is, for example, the thickness of the transparent sheet 1 after peeling off the peelable cover layer that is peeled off during use (i.e., the thickness excluding the peelable cover layer that is peeled off during use). 200 to 700 μm, preferably 250 to 600 μm. Furthermore, as the mass of the transparent sheet 1 of the present invention, for example, the mass of the transparent sheet 1 after peeling off the peelable cover layer that is peeled off during use (that is, the mass excluding the peelable cover layer that is peeled off during use). However, the range is 200 to 800 g/m ² , and preferably 400 to 750 g/m ² . In addition, the total weight of the resin in the transparent sheet 1 after peeling off the peelable cover layer that is peeled off during use (for example, when the transparent sheet 1 has the laminated structure shown in FIG. 4, the first resin layer 3, the second resin layer The total resin mass of the resin layer 4 and the film layer 5 is, for example, 300 to 700 g/m ² , preferably 390 to 700 g/m ² , and more preferably 450 to 650 g/m ² .

The transparent sheet 1 of the present invention has a removable cover layer that is peeled off during use, and the transparent sheet 1 is compliant with the "Fireproof Performance Testing and Evaluation Procedures Manual" (March 2014) of the Building Materials Testing Center, a general incorporated foundation. In a heat generation test that irradiates the surface of the sheet with 50kW/ ^m2 of radiant heat from a radiant electric heater, which is measured in accordance with "4.10.2 Heat generation test/evaluation method" in is preferably 8 MJ/m ² or less. Further, the transparent sheet 1 of the present invention has a maximum heat generation rate of 200 kW after the start of heating for 10 seconds or more in the heat generation test described above after peeling off the peelable cover layer that is peeled off during use. / ^m2 .

In addition, in the present invention, according to "4.10.2 Pyrogenicity test/evaluation method" in "Fireproof performance test/evaluation work method manual" (revised version on March 1, 2014) of the Building Materials Testing Center, a general incorporated foundation. The total calorific value (MJ/m ² ) and the maximum heat generation rate after the start of heating exceed 200 kW/m ² in a heat generation test in which radiant heat of 50 kW/m ² is irradiated onto the surface of the sheet from a radiant electric heater. Specifically, the time (S) is determined according to the contents described in the test specimen, test apparatus, and test conditions shown below.

[Test specimen]
(1) The number of test specimens (sheets) shall be three.
(2) The shape and dimensions of the test specimen shall be a square with each side measuring 99 mm±1 mm.
[Test equipment]
(1) A schematic diagram of the test equipment used is shown in FIG. The test equipment consists of a conical radiant electric heater, an ignition plug, a radiant heat shield, a test specimen holder, a gas concentration analyzer, an exhaust system capable of measuring gas flow rate, and a heat flow meter.
(2) The radiant electric heater shall be capable of stably and uniformly irradiating the surface of the test piece with 50 kW/m ² of radiant heat.
(3) The radiant heat shielding plate shall be capable of protecting the test specimen from radiant heat before the test begins.
(4) A schematic diagram of the test holder and holding frame included in the test device is shown in FIG. The specimen holder is made of stainless steel and has a square shape with external dimensions of 106 mm ± 1 mm on a side, a depth of 25 mm ± 1 mm, and a thickness of 2.15 mm ± 0.25 mm. A square opening of .0 mm±0.5 mm shall be provided in the center. The holding frame is made of stainless steel and has a square shape with an inner dimension of 111 mm ± 1 mm on a side and a depth of 54 mm ± 1 mm.
(5) The exhaust system shall be equipped with a centrifugal exhaust fan, hood, vent, exhaust duct, orifice plate flow meter, etc. that function effectively at the test temperature. The distance between the lower end of the hood and the surface of the test specimen shall be 210 mm ± 50 mm, and in this state, the exhaust system's exhaust system shall have a flow rate of 0.024 m ³ /s or more when converted to standard temperature and standard pressure. . To measure the exhaust flow rate, an orifice with an inner diameter of 57 mm±3 mm is provided between the hood and the duct. For the purpose of exhaust gas sampling, a ring sampler with 12 holes 2.2 mm ± 0.1 mm in diameter is mounted 685 mm ± 15 mm from the hood with the holes facing away from the flow. Also, the temperature of the exhaust gas is measured at the center of the exhaust duct at a position 100 mm±5 mm upstream from the orifice. The orifice is installed at a location that does not affect flow measurement.
(6) The gas analyzer shall be capable of continuously and accurately measuring the concentrations of oxygen, carbon monoxide, and carbon dioxide in exhaust gas.
(7) The spark plug shall be capable of supplying power from a 10 kV transformer or induction coil system. The distance between the spark electrodes is 3 mm±0.5 mm, and the position of the electrodes is, in principle, 13 mm±2 mm on the central axis of the test piece.
(8) The heat flow meter uses a Schmidt-Boulder type that can measure up to 100 kW/m ² ±10 kW/m ² . The heat sensing part of the heat flow meter is assumed to be circular with a diameter of 12.5 mm, and the emissivity of the surface is 0.95±0.05.
[Test condition]
(1) The test time shall be 20 minutes after radiant heat is irradiated onto the surface of the test piece and an electric spark is activated at the same time. However, the measurement may be terminated when combustion clearly no longer continues.
(2) The test specimen was wrapped with aluminum foil with a thickness of 0.025 mm or more and 0.04 mm or less on the side and back sides, placed in a holding frame, and inorganic fibers (nominal thickness 13 mm, density 65 kg/m ³ ) and then push it into the test specimen holder.
(3) During the test, radiant heat of 50 kW/m ² is applied to the surface of the test specimen from a radiant electric heater.
(4) Adjust the exhaust gas flow rate to 0.024 m ³ /s±0.002 m ³ /s.
(5) Until the start of the test, use a radiant heat shield to prevent the test specimen from receiving radiant heat.
(6) Before moving the radiant heat shield, set the ignition plug in the specified position.
[measurement]
(1) Measure the concentrations of oxygen, carbon monoxide, and carbon dioxide at intervals of 5 seconds or less.
(2) Using the method shown below, calculate the heat generation rate per unit area (kW/m ² ), and then calculate the total heat generation amount per unit area (MJ/m ² ) as the heat generation rate during the time from the start to the end of heating. Calculated by accumulating.

The heat generation rate (q) is calculated according to the following formula.

here,
V ₂₉₈ = C (Δp・Te) ^1/2 /350 (: flow rate in the duct at 25°C)
E=17.2×10 ³ kJ/m ³
X ⁰ _O2 : Average value of oxygen concentration based on 1-minute baseline measurement X _O2 : Actual measured value of oxygen concentration
q”=q/As
here,
As: initial exposed area of test specimen (0.0088 m ² ).
C (orifice coefficient) is the oxygen concentration (X _O2 ) and differential pressure when methane is burned at a flow rate corresponding to a heat generation rate of q _b = 5 kW ± 0.5 kW in this measurement under a specified exhaust flow rate. Calculate from (Δp) using the following formula.
C=q _b / (△hc/ro×1.10) (Te/△p) ^1/2 (1.105-1.5X _O2 )/(0.2095-X _O2 )
here,
q _b : Heat generation rate of supplied methane △hc/ro: 12.54×10 ³ kJ/kg for methane
Te: Gas temperature in the exhaust duct (value measured near the two-way pitot tube)

(Method for manufacturing transparent sheet 1 of the present invention)
The method for producing the transparent sheet 1 of the present invention is not particularly limited, but includes, for example, a first step of preparing an intermediate in which the glass fiber fabric 2 is impregnated with the first resin layer 3; A second step of laminating the second resin layer 4 may be included. An example of the laminated structure shown in FIG. 1 will be described below.

The first step will be described using a case where the resin constituting the first resin layer 3 is a curable resin. In the first step, first, a glass fiber fabric 2 and an uncured curable resin composition to be used as the first resin layer 3 are prepared. The uncured curable resin composition is applied to a process film (for example, a PET film, etc.), the glass fiber fabric 2 is placed on the applied uncured curable resin composition, and the uncured glass fiber fabric 2 is coated with the uncured curable resin composition. curable resin composition. Next, another process film (for example, PET film, etc.) is placed on top of the uncured curable resin composition impregnated into the glass fiber fabric 2, and pressure is applied with a roller from above the process film B to remove the first resin. Adjust the mass of layer 3. Thereafter, the uncured curable resin composition that is to be the first resin layer 3 is irradiated with light through the PET film B using a black light fluorescent lamp to cure the curable resin composition. After forming layer 3, one of the laminated process films (in this example, process film A for convenience) is peeled off, and the first layer impregnated in process film B/glass fiber fabric 2 is removed. An intermediate body having a laminated structure of resin layers 3 can be obtained. Two sheets of the intermediate are prepared. At this time, when the transparent sheet 1 includes the film layer 5, the film layer 5 can be used instead of the process film B included in the intermediate. Further, when the transparent sheet 1 includes, for example, a film layer 5 and a peelable cover layer that is peeled off during use, the film layer 5 and a peelable cover layer that is peeled off during use are laminated in advance. A laminated film may be used, and the laminated film may be used in place of the process film B included in the intermediate so that the cover layer is on the surface side.

The second step will be described using a case where the resin constituting the second resin layer 4 is a curable resin. In the second step, an uncured curable resin to be used as the second resin layer 4 is prepared, and the uncured curable resin is applied to the first resin layer 3 side of the intermediate obtained in the first step. Apply to. Next, on top of the uncured curable resin that will become the second resin layer 4, place the other of the obtained intermediate so that the first resin layer 3 side is the uncured hardened resin that will become the second resin layer 4. The mass of the second resin layer 4 is adjusted by applying pressure with a roller from above the other intermediate body. Thereafter, the uncured curable resin composition that will form the second resin layer 4 is irradiated with light through the other intermediate using a black light fluorescent lamp to cure the curable resin composition. 2. A resin layer 4 is formed and laminated. By peeling off the process film B on both surfaces of the second resin layer 4, the first resin layer 3 contained in the glass fiber fabric 2 in an impregnated state/contained in the glass fiber fabric 2 in an unimpregnated state is removed. The transparent sheet 1 of the present invention having a laminated structure of the second resin layer 4/the first resin layer 3 impregnated in the glass fiber fabric 2 can be obtained. Note that when the film layer 5 is included or a cover layer that can be peeled off during use is included, the second resin layer 4 is formed by curing the uncured curable resin composition that will become the second resin layer 4. After forming and laminating, the transparent sheet 1 may be obtained by leaving the film layer 5 and the cover layer which can be peeled off during use without peeling off.

(Applications of transparent sheet 1 of the present invention)
The transparent sheet 1 of the present invention can be used as a smoke-proof hanging wall that is hung from the ceiling of a building. Examples of smoke-proof hanging walls include known ones that use a transparent sheet 1 made of glass fiber fabric and resin. It comprises a transparent sheet 1 held and suspended, and a pair of end mullions arranged on both sides of the transparent sheet 1, and the transparent sheet 1 and the end mullions are separably joined. Examples include smoke-proof hanging walls. The smoke-proof hanging wall may also include a hanging wall in which a transparent sheet 1 is stretched between two pairs of mullions. For example, the lower side of the transparent sheet 1 when installed hanging from a ceiling. An example of this is smoke-proof hanging walls that do not have blinds. In addition, if the transparency is increased, it can be used as a substitute for glass, so it can be used in other applications where glass is used, such as partitions, room partitions, smoke-proof sheets, and smoke-proof curtains (such as those used in factories). ), etc.

The present invention will be explained in detail below by showing Examples and Comparative Examples. However, the present invention is not limited to the examples.

In Examples 1 to 6, the resin composition constituting the first resin layer 3 impregnated into the glass fiber fabric 2 was acrylic syrup (a product manufactured by Ryoko Co., Ltd. RDP (product name: "Acrisilap The mixture (mass ratio (acrylic syrup: non-halogen condensed phosphoric acid ester compound: photopolymerization initiator) = 70:30:3), in Examples 7 to 10, acrylic syrup (trade name "XY1087" manufactured by Ryoko Co., Ltd.) A mixture of "XY1088 (refractive index 1.540), tetrabromobisphenol A (TBBA, product name "Frame Cut 120G" manufactured by Tosoh Corporation) and a photopolymerization initiator (Omnirad 184 manufactured by IGM) Mass ratio (acrylic syrup XY1087: acrylic syrup XY1088: TBBA: photopolymerization initiator) = 34:42:24:3) was used.Constitutes the second resin layer 4, which is contained in the glass fiber fabric 2 without being impregnated. The resin composition used was a mixture of a brominated vinyl ester resin (product name: Neopol 8197, manufactured by Nippon U-Pica Co., Ltd.) and a photopolymerization initiator (Omnirad 184, manufactured by IGM Co., Ltd.) so as to have the composition shown in Table 1. The amount of the photopolymerization initiator was 3 parts by mass per 100 parts by mass of the brominated vinyl ester resin.For the film layer 5, two kinds of commercially available biaxially stretched polyester films manufactured by Toyobo Co., Ltd. (trade name "Cosmo") were used. Shine (registered trademark) A4300", thickness 38 μm, mass 53 g/m ² , total light transmittance (JIS K 7105:1981) 93%, haze (JIS K 7105:1981) 0.9%), (product name " Cosmoshine (registered trademark) A4300", thickness 50 μm, mass 70 g/m ² , total light transmittance (JIS K 7105:1981) 93%, haze (JIS K 7105:1981) 0.9%), and commercially available A film containing PVDF and acrylic resin (Sheet A is an alloy of PVDF and PMMA, with a PVDF content of 80% by mass and a PMMA content of 20% by mass, and a PVDF content of 20% by mass) %, and sheet B having a PMMA content of 80% by mass (manufactured by Denka Co., Ltd., product name "Denka DX Film DX-14S50", thickness 50 μm, mass 68 g/m ² , total A light transmittance (JIS K 7105:1981) of 92% and a haze (JIS K 7105:1981) of 5%) were used. As a removable cover layer that is peeled off during use, an acrylic ester adhesive is applied on one side of a polypropylene film (thickness: 40 μm, mass: 36 g/m ² ) to releasably adhere to the film layer 5. and a PET film (thickness: 50 μm, total light transmittance: 93%, haze: 4% (JIS K 7105:1981)). The PET film was also used as a process film to be described later.

<Example 1>
(Preparation of glass fiber fabric)
Unitika Glass Fiber Co., Ltd. product name "ECC1200 1/0 1.0Z" (average filament diameter 4.5 μm, average number of filaments 100, number of twists 1.0Z, count 4.2tex) was used as the warp and weft, and air A plain weave glass fiber fabric having a warp density of 90 threads/25 mm and a weft thread density of 90 threads/25 mm was obtained by weaving with a jet loom. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass fiber fabric were removed by heating at 400° C. for 30 hours. After that, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Corporation) was adjusted to a concentration of 15 g/L and squeezed with a padder roll. After that, it was dried and cured at 120°C for 1 minute. Then, the glass fiber fabric was widened once by water jet processing at a pressure of 1.5 MPa while the tension of the glass fiber fabric was set to 100 N/m in the warp direction to obtain a glass fiber fabric 2. The obtained glass fiber fabric had a warp density of 90/25 mm, a weft density of 90/25 mm, a thickness of 27 μm, a mass of 30 g/m ² , and a refractive index of 1.561.

(Lamination of antistatic layer on film layer 5)
An antistatic layer was laminated on one surface of Cosmoshine (registered trademark) A4300 (thickness: 38 μm) serving as the film layer 5. The antistatic layer is made by adding tin oxide fine particles (average particle size 20 nm) in a polyester resin as a binding resin such that the mass ratio of the binding resin to the tin oxide fine particles (fixing resin: tin oxide fine particles) is 75:25. The mixed and dispersed antistatic agent was coated on one side of Cosmoshine (registered trademark) A4300 (thickness: 38 μm) to serve as film layer 5, and then dried. The provided antistatic layer had a mass of 0.5 g/m ² and a thickness of 0.4 μm.

(Lamination of a removable protective film to film layer 5 (antistatic layer side) that is peeled off during use)
On the antistatic layer of Cosmoshine (registered trademark) A4300, which is the film layer 5 and has the antistatic layer on one side, the polypropylene is used as the peelable cover layer that is peeled off during use. A removable protective film that is coated with an acrylic ester adhesive on one side of the film and is laminated with the adhesive facing the antistatic layer, dried, and peeled off during use. A laminate X having a laminate structure of acrylic acid ester adhesive/antistatic layer/Cosmoshine (registered trademark) A4300 as film layer 5 was obtained. Two laminates X were prepared.

(Formation of the first resin layer 3 and lamination of the laminate A including the film layer 5 onto the first resin layer 3)
The first resin layer 3 is formed on the Cosmoshine (registered trademark) A4300 side (that is, the side opposite to the peelable cover layer that is peeled off during use) of the laminate A curable resin composition consisting of acrylic syrup was applied. Next, the obtained glass fiber fabric 2 is placed on the curable resin composition which is to be used as the first resin layer 3, and left to stand for 1 minute. It was impregnated with a curable resin composition. Next, the PET film used as the process film described above is placed on the curable resin composition made of the acrylic syrup, and a roller is applied from above the PET film so that the mass of the first resin layer 3 is 30 g/ ^m2 . It was pressurized like this. Thereafter, the curable resin composition made of acrylic syrup, which will become the first resin layer 3, is passed through the PET film in the above step and irradiated with light using a black light fluorescent lamp (product name: FL15BLB, manufactured by Toshiba Corporation) (light irradiation conditions: The curable resin composition is cured with an integrated light amount of 200 mJ/cm ² ) to form the first resin layer 3, and then the laminated process PET film is peeled off to form a peelable film that is peeled off during use. Cover layer/Acrylic acid ester adhesive that can be peeled off together with the cover layer/Antistatic layer/Film layer 5 (Cosmoshine (registered trademark) A4300)/First resin layer impregnated in the glass fiber fabric 2 A laminate Y having the laminate structure of No. 3 was obtained. In the obtained laminate Y, the gaps between the glass fibers of the glass fiber fabric 2 are impregnated with the first resin layer 3 (cured product of the resin composition) made of acrylic syrup without exposing the glass fibers. Ta. Two pieces of the laminate Y were prepared.

(Lamination of the second resin layer 4 contained in the glass fiber fabric 2 in an unimpregnated state)
The second resin layer 4 contained in the glass fiber fabric 2 in an unimpregnated state is formed on the side of the first resin layer 3 impregnated in the glass fiber fabric 2 of the laminate Y obtained above. The brominated vinyl ester resin composition described in 1 was applied. Next, the other of the obtained laminate Y is placed on top of the brominated vinyl ester resin composition, with the first resin layer 3 side of the laminate Y facing the brominated vinyl ester resin composition. Then, pressure was applied from above the other laminate Y using a roller so that the mass of the second resin layer 4 made of the brominated vinyl ester resin composition was 183 g/m ² . Thereafter, the brominated vinyl ester resin composition that is to be the second resin layer 4 is passed through the other laminate Y and irradiated with light (light irradiation conditions : The second resin layer 4 is formed by curing the brominated vinyl ester resin composition with an integrated light amount of 200 mJ/cm ² ), and a removable cover layer that is peeled off during use/acrylic that can be peeled off together with the cover layer. Acid ester adhesive/antistatic layer/film layer 5 (Cosmoshine (registered trademark) A4300)/first resin layer 3 impregnated in glass fiber fabric 2/not impregnated in glass fiber fabric 2 Second resin layer 4 included in the glass fiber fabric 2 / First resin layer 3 included in the impregnated state of the glass fiber fabric 2 / Film layer 5 (Cosmoshine (registered trademark) A4300) / Antistatic layer / Peelable together with the cover layer A transparent sheet 1 of the present invention having a laminated structure of an acrylic ester adhesive/a removable cover layer that is peeled off during use was obtained. Note that the evaluation of the bromine concentration, total light transmittance, haze, total calorific value, and time over 200 kW of the transparent sheet described below is based on the peelable cover layer that is peeled off when using the transparent sheet 1 obtained above and the cover. The peelable acrylic ester adhesive was peeled off along with the layer.

<Example 2>
In the lamination of the second resin layer 4 included in the glass fiber fabric 2 in an unimpregnated state in Example 1, the second resin layer made of a brominated vinyl ester resin composition is applied from above the other laminate Y using a roller. A removable cover layer that is peeled off during use/ ^an acrylic ester adhesive that can be peeled off together with the cover layer. /Antistatic layer/Film layer 5 (Cosmoshine (registered trademark) A4300)/First resin layer 3 included in the glass fiber fabric 2 in an impregnated state/Second resin layer included in the glass fiber fabric 2 in an unimpregnated state Resin layer 4 / First resin layer 3 impregnated in glass fiber fabric 2 / Film layer 5 (Cosmoshine (registered trademark) A4300) / Antistatic layer / Acrylic acid ester adhesive that can be peeled off together with the cover layer A transparent sheet 1 of the present invention having a laminated structure of an agent/a removable cover layer that is peeled off at the time of use was obtained. Note that the evaluation of the bromine concentration, total light transmittance, haze, total calorific value, and time over 200 kW of the transparent sheet described below is based on the peelable cover layer that is peeled off when using the transparent sheet 1 obtained above and the cover. The peelable acrylic ester adhesive was peeled off along with the layer.

<Example 3>
In the lamination of the second resin layer 4 included in the glass fiber fabric 2 in an unimpregnated state in Example 1, the second resin layer made of a brominated vinyl ester resin composition is applied from above the other laminate Y using a roller. A removable cover layer that ^is peeled off during use/an acrylic ester adhesive that is removable together with the cover layer. /Antistatic layer/Film layer 5 (Cosmoshine (registered trademark) A4300)/First resin layer 3 included in the glass fiber fabric 2 in an impregnated state/Second resin layer included in the glass fiber fabric 2 in an unimpregnated state Resin layer 4 / First resin layer 3 impregnated in glass fiber fabric 2 / Film layer 5 (Cosmoshine (registered trademark) A4300) / Antistatic layer / Acrylic acid ester adhesive that can be peeled off together with the cover layer A transparent sheet 1 of the present invention having a laminated structure of a removable cover layer and a removable cover layer that is peeled off at the time of use was obtained. Note that the evaluation of the bromine concentration, total light transmittance, haze, total calorific value, and time over 200 kW of the transparent sheet described below is based on the peelable cover layer that is peeled off when using the transparent sheet 1 obtained above and the cover. The peelable acrylic ester adhesive was peeled off along with the layer.

<Example 4>
In the lamination of the second resin layer 4 included in the glass fiber fabric 2 in an unimpregnated state in Example 1, the second resin layer made of a brominated vinyl ester resin composition is applied from above the other laminate Y by a roller. A removable cover layer that is peeled off at the time ^of use/an acrylic ester adhesive that is removable together with the cover layer /Antistatic layer/Film layer 5 (Cosmoshine (registered trademark) A4300)/First resin layer 3 included in the glass fiber fabric 2 in an impregnated state/Second resin layer included in the glass fiber fabric 2 in an unimpregnated state Resin layer 4 / First resin layer 3 impregnated in glass fiber fabric 2 / Film layer 5 (Cosmoshine (registered trademark) A4300) / Antistatic layer / Acrylic acid ester adhesive that can be peeled off together with the cover layer A transparent sheet 1 of the present invention having a laminated structure of a removable cover layer and a removable cover layer that is peeled off at the time of use was obtained. Note that the evaluation of the bromine concentration, total light transmittance, haze, total calorific value, and time over 200 kW of the transparent sheet described below is based on the peelable cover layer that is peeled off when using the transparent sheet 1 obtained above and the cover. The peelable acrylic ester adhesive was peeled off along with the layer.

<Example 5>
(Preparation of glass fiber fabric)
Unitika Glass Fiber Co., Ltd. product name "ECE225 1/0 1.0Z" (average filament diameter 7.0 μm, average number of filaments 200, number of twists 1.0Z, count 22.5tex) was used as the warp and weft, and air A plain weave glass fiber fabric having a warp density of 60 threads/25 mm and a weft thread density of 57 threads/25 mm was obtained by weaving with a jet loom. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass fiber fabric were removed by heating at 400° C. for 30 hours. After that, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Corporation) was adjusted to a concentration of 15 g/L and squeezed with a padder roll. After that, it was dried and cured at 120° C. for 1 minute to obtain a glass fiber fabric 2. The obtained glass fiber fabric had a warp density of 60/25 mm, a weft density of 57/25 mm, a thickness of 90 μm, a mass of 105 g/m ² , and a refractive index of 1.561.

(Formation of first resin layer 3 and lamination of film layer 5 on first resin layer 3)
A curable resin composition consisting of acrylic syrup shown in Table 1 and used as the first resin layer 3 was applied to the PET film used as the process film described above. Next, the obtained glass fiber fabric 2 is placed on the curable resin composition which is to be used as the first resin layer 3, and left to stand for 1 minute. It was impregnated with a curable resin composition. Next, another PET film used as the process film described above is placed on the curable resin composition made of the acrylic syrup, and a roller is applied from above the PET film to reduce the mass of the first resin layer 3 to 105 g/m. The pressure was applied to ² . Thereafter, the curable resin composition made of acrylic syrup, which will become the first resin layer 3, is passed through the PET film in the above step and irradiated with light using a black light fluorescent lamp (product name: FL15BLB, manufactured by Toshiba Corporation) (light irradiation conditions: The curable resin composition was cured with an integrated light amount of 200 mJ/cm ² ) to form the first resin layer 3, and then one PET film used as the process film laminated above was peeled off to form a process film. A laminate Z having a laminate structure of the first resin layer 3 impregnated with the PET film/glass fiber fabric 2 to be used as a sample was obtained. In the obtained laminate Z, the first resin layer 3 made of acrylic syrup (cured product of the resin composition) is impregnated into the gaps between the glass fibers of the glass fiber fabric 2 without exposing the glass fibers. Ta. Two pieces of the laminate Z were prepared.

(Lamination of the second resin layer 4 contained in the glass fiber fabric 2 in an unimpregnated state)
The second resin layer 4 contained in the glass fiber fabric 2 in an unimpregnated state is placed on the side of the first resin layer 3 impregnated in the glass fiber fabric 2 of the laminate Z obtained above. The brominated vinyl ester resin composition described in 1 was applied. Next, the other of the obtained laminate Z is placed on top of the brominated vinyl ester resin composition, with the first resin layer 3 side of the laminate Z facing the brominated vinyl ester resin composition. Then, pressure was applied from above the other laminate Z using a roller so that the mass of the second resin layer 4 made of the brominated vinyl ester resin composition was 184 g/m ² . Thereafter, the brominated vinyl ester resin composition that is to be the second resin layer 4 is passed through the other laminate Z and irradiated with light (light irradiation conditions : The brominated vinyl ester resin composition is cured with an integrated light amount of 200 mJ/cm ² ) to form the second resin layer 4, and the PET film used as the process film on both sides is peeled off, and the glass fiber fabric 2 is impregnated with the PET film. First resin layer 3 included in the glass fiber fabric 2 / Second resin layer 4 included in the glass fiber fabric 2 in an unimpregnated state / First resin layer 3 included in the glass fiber fabric 2 in an impregnated state I got a body. The obtained laminate is used as the film layer 5. Two sheets containing the above-mentioned PVDF and acrylic resin are used, and the surface of both sheets to be adhered to the laminate is on the sheet B side (i.e., the acrylic resin-rich surface). ), and pressed with a hot press at a temperature of 160° C., a press pressure of 10 kgf/cm ² , and a time of 5 minutes to adhere the laminate to a sheet containing PVDF and acrylic resin. Film layer 5 (sheet containing PVDF and acrylic resin) / First resin layer 3 included in the glass fiber fabric 2 in an impregnated state / Second resin layer 4 included in the glass fiber fabric 2 in an unimpregnated state A transparent sheet 1 of the present invention having a laminated structure of a first resin layer 3/film layer 5 (sheet containing PVDF and acrylic resin) impregnated into a glass fiber fabric 2 was obtained. The transparent sheet obtained above was used to evaluate the bromine concentration, total light transmittance, haze, total calorific value, and time over 200 kW of the transparent sheet, which will be described later.

<Example 6>
(Preparation of glass fiber fabric)
Unitika Glass Fiber Co., Ltd. product name "ECBC2250 1/0 0.5Z" (average filament diameter 4.0 μm, average number of filaments 66, number of twists 0.5Z, count 2.3tex) was used as the warp and weft, and air A plain weave glass fiber fabric having a warp density of 95 threads/25 mm and a weft thread density of 95 threads/25 mm was obtained by weaving with a jet loom. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass fiber fabric were removed by heating at 400° C. for 30 hours. After that, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Corporation) was adjusted to a concentration of 15 g/L and squeezed with a padder roll. After that, it was dried and cured at 120° C. for 1 minute to obtain a glass fiber fabric 2. The obtained glass fiber fabric had a warp density of 95/25 mm, a weft density of 95/25 mm, a thickness of 15 μm, a mass of 17 g/m ² , and a refractive index of 1.561.

(Lamination of antistatic layer on film layer 5)
An antistatic layer was laminated on one surface of Cosmoshine (registered trademark) A4300 (thickness: 50 μm) serving as the film layer 5. The antistatic layer is made by adding tin oxide fine particles (average particle size 20 nm) in a polyester resin as a binding resin such that the mass ratio of the binding resin to the tin oxide fine particles (fixing resin: tin oxide fine particles) is 75:25. The mixed and dispersed antistatic agent was coated on one side of Cosmoshine (registered trademark) A4300 (thickness: 50 μm) to serve as film layer 5, and then dried. The provided antistatic layer had a mass of 0.5 g/m ² and a thickness of 0.4 μm.

(Lamination of a removable protective film to film layer 5 (antistatic layer side) that is peeled off during use)
On the antistatic layer of Cosmoshine (registered trademark) A4300, which is the film layer 5 and has the antistatic layer on one side, the polypropylene is used as the peelable cover layer that is peeled off during use. A removable protective film that is coated with an acrylic ester adhesive on one side of the film and is laminated with the adhesive facing the antistatic layer, dried, and peeled off during use. A laminate X having a laminate structure of acrylic acid ester adhesive/antistatic layer/Cosmoshine (registered trademark) A4300 as film layer 5 was obtained. Two laminates X were prepared.

(Formation of the first resin layer 3 and lamination of the laminate A including the film layer 5 onto the first resin layer 3)
The first resin layer 3 is formed on the Cosmoshine (registered trademark) A4300 side (that is, the side opposite to the peelable cover layer that is peeled off during use) of one laminate A curable resin composition consisting of acrylic syrup was applied. Next, the obtained glass fiber fabric 2 is placed on the curable resin composition which is to be used as the first resin layer 3, and left to stand for 1 minute. It was impregnated with a curable resin composition. Next, the PET film used as the process film described above is placed on the curable resin composition made of the acrylic syrup, and a roller is applied from above the PET film so that the mass of the first resin layer 3 is 25 g/ ^m2 . It was pressurized like this. Thereafter, the curable resin composition made of acrylic syrup, which will become the first resin layer 3, is passed through the PET film in the above step and irradiated with light using a black light fluorescent lamp (product name: FL15BLB, manufactured by Toshiba Corporation) (light irradiation conditions: The curable resin composition is cured with an integrated light amount of 200 mJ/cm ² ) to form the first resin layer 3, and the laminated process PET film is then peeled off to form a peelable film that is peeled off during use. Cover layer/Acrylic acid ester adhesive that can be peeled off together with the cover layer/Antistatic layer/Film layer 5 (Cosmoshine (registered trademark) A4300)/First resin layer impregnated in the glass fiber fabric 2 A laminate Y having the laminate structure of No. 3 was obtained. In the obtained laminate Y, the gaps between the glass fibers of the glass fiber fabric 2 are impregnated with the first resin layer 3 (cured product of the resin composition) made of acrylic syrup without exposing the glass fibers. Ta. Two pieces of the laminate Y were prepared.

(Lamination of the second resin layer 4 contained in the glass fiber fabric 2 in an unimpregnated state)
The second resin layer 4 contained in the glass fiber fabric 2 in an unimpregnated state is formed on the side of the first resin layer 3 impregnated in the glass fiber fabric 2 of the laminate Y obtained above. The brominated vinyl ester resin composition described in 1 was applied. Next, the other of the obtained laminate Y is placed on top of the brominated vinyl ester resin composition, with the first resin layer 3 side of the laminate Y facing the brominated vinyl ester resin composition. Then, pressure was applied from above the other laminate Y using a roller so that the mass of the second resin layer 4 made of the brominated vinyl ester resin composition was 387 g/m ² . Thereafter, the brominated vinyl ester resin composition that is to be the second resin layer 4 is passed through the other laminate Y and irradiated with light (light irradiation conditions : The second resin layer 4 is formed by curing the brominated vinyl ester resin composition with an integrated light amount of 200 mJ/cm ² ), and a removable cover layer that is peeled off during use/acrylic that can be peeled off together with the cover layer. Acid ester adhesive/antistatic layer/film layer 5 (Cosmoshine (registered trademark) A4300)/first resin layer 3 impregnated in glass fiber fabric 2/not impregnated in glass fiber fabric 2 Second resin layer 4 included in the glass fiber fabric 2 / First resin layer 3 included in the impregnated state of the glass fiber fabric 2 / Film layer 5 (Cosmoshine (registered trademark) A4300) / Antistatic layer / Peelable together with the cover layer A transparent sheet 1 of the present invention having a laminated structure of an acrylic ester adhesive/a removable cover layer that is peeled off during use was obtained. Note that the evaluation of the bromine concentration, total light transmittance, haze, total calorific value, and time over 200 kW of the transparent sheet described below is based on the peelable cover layer that is peeled off when using the transparent sheet 1 obtained above and the cover. The peelable acrylic ester adhesive was peeled off along with the layer.

<Example 7>
(Preparation of glass fiber fabric)
The product name "ECC1200 1/0 1.0Z" manufactured by Unitika Glass Fiber Co., Ltd. (average filament diameter 4.5 μm, average number of filaments 100, number of twists 1.0Z, count 4.2tex) was used as the warp and weft, and air A plain weave glass fiber fabric having a warp density of 90 threads/25 mm and a weft thread density of 90 threads/25 mm was obtained by weaving with a jet loom. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass fiber fabric were removed by heating at 400° C. for 30 hours. After that, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Corporation) was adjusted to a concentration of 15 g/L and squeezed with a padder roll. After that, it was dried and cured at 120°C for 1 minute. Then, the glass fiber fabric was widened once by water jet processing at a pressure of 1.5 MPa while the tension of the glass fiber fabric was set to 100 N/m in the warp direction to obtain a glass fiber fabric 2. The obtained glass fiber fabric had a warp density of 90/25 mm, a weft density of 90/25 mm, a thickness of 27 μm, a mass of 30 g/m ² , and a refractive index of 1.561.

(Lamination of antistatic layer on film layer 5)
An antistatic layer was laminated on one surface of Cosmoshine (registered trademark) A4300 (thickness: 50 μm) serving as the film layer 5. The antistatic layer is made by adding tin oxide fine particles (average particle diameter 20 nm) in a polyester resin as a binding resin such that the mass ratio of the binding resin to the tin oxide fine particles (fixing resin: tin oxide fine particles) is 75:25. The mixed and dispersed antistatic agent was coated on one side of Cosmoshine (registered trademark) A4300 (thickness: 50 μm) to serve as film layer 5, and then dried. The provided antistatic layer had a mass of 0.5 g/m ² and a thickness of 0.4 μm.

(Lamination of a removable protective film to film layer 5 (antistatic layer side) that is peeled off during use)
On the antistatic layer of Cosmoshine (registered trademark) A4300, which is the film layer 5 and has the antistatic layer on one side, the polypropylene is used as the peelable cover layer that is peeled off during use. A removable protective film that is coated with an acrylic ester adhesive on one side of the film and is laminated with the adhesive facing the antistatic layer, dried, and peeled off during use. A laminate X having a laminate structure of acrylic acid ester adhesive/antistatic layer/Cosmoshine (registered trademark) A4300 as film layer 5 was obtained. Two laminates X were prepared.

(Formation of the first resin layer 3 and lamination of the laminate A including the film layer 5 on the first resin layer 3)
The first resin layer 3 is formed on the Cosmoshine (registered trademark) A4300 side (that is, the side opposite to the peelable cover layer that is peeled off during use) of one laminate A curable resin composition consisting of acrylic syrup was applied. Next, the obtained glass fiber fabric 2 is placed on the curable resin composition which is to be used as the first resin layer 3, and left to stand for 1 minute. It was impregnated with a curable resin composition. Next, the PET film used as the process film described above is placed on the curable resin composition made of the acrylic syrup, and a roller is applied from above the PET film so that the mass of the first resin layer 3 is 25 g/ ^m2 . It was pressurized like this. Thereafter, the curable resin composition made of acrylic syrup, which will become the first resin layer 3, is passed through the PET film in the above step and irradiated with light using a black light fluorescent lamp (product name: FL15BLB, manufactured by Toshiba Corporation) (light irradiation conditions: The curable resin composition is cured with an integrated light amount of 200 mJ/cm ² ) to form the first resin layer 3, and the laminated process PET film is then peeled off to form a peelable film that is peeled off during use. Cover layer/Acrylic acid ester adhesive that can be peeled off together with the cover layer/Antistatic layer/Film layer 5 (Cosmoshine (registered trademark) A4300)/First resin layer impregnated in the glass fiber fabric 2 A laminate Y having the laminate structure of No. 3 was obtained. In the obtained laminate Y, the gaps between the glass fibers of the glass fiber fabric 2 are impregnated with the first resin layer 3 (cured product of the resin composition) made of acrylic syrup without exposing the glass fibers. Ta. Two pieces of the laminate Y were prepared.

(Lamination of the second resin layer 4 contained in the glass fiber fabric 2 in an unimpregnated state)
The second resin layer 4 contained in the glass fiber fabric 2 in an unimpregnated state is formed on the side of the first resin layer 3 impregnated in the glass fiber fabric 2 of the laminate Y obtained above. The brominated vinyl ester resin composition described in 1 was applied. Next, the other of the obtained laminate Y is placed on top of the brominated vinyl ester resin composition, with the first resin layer 3 side of the laminate Y facing the brominated vinyl ester resin composition. Then, pressure was applied from above the other laminate Y using a roller so that the mass of the second resin layer 4 made of the brominated vinyl ester resin composition was 149 g/m ² . Thereafter, the brominated vinyl ester resin composition that is to be the second resin layer 4 is passed through the other laminate Y and irradiated with light (light irradiation conditions : The second resin layer 4 is formed by curing the brominated vinyl ester resin composition with an integrated light amount of 200 mJ/cm ² ), and a removable cover layer that is peeled off during use/acrylic that can be peeled off together with the cover layer. Acid ester adhesive/antistatic layer/film layer 5 (Cosmoshine (registered trademark) A4300)/first resin layer 3 impregnated in glass fiber fabric 2/not impregnated in glass fiber fabric 2 Second resin layer 4 included in the glass fiber fabric 2 / First resin layer 3 included in the impregnated state of the glass fiber fabric 2 / Film layer 5 (Cosmoshine (registered trademark) A4300) / Antistatic layer / Peelable together with the cover layer A transparent sheet 1 of the present invention having a laminated structure of an acrylic ester adhesive/a removable cover layer that is peeled off during use was obtained. Note that the evaluation of the bromine concentration, total light transmittance, haze, total calorific value, and time over 200 kW of the transparent sheet described below is based on the peelable cover layer that is peeled off when using the transparent sheet 1 obtained above and the cover. The peelable acrylic ester adhesive was peeled off along with the layer.

<Example 8>
(Preparation of glass fiber fabric)
Unitika Glass Fiber Co., Ltd. product name "ECC1200 1/0 1.0Z" (average filament diameter 4.5 μm, average number of filaments 100, number of twists 1.0Z, count 4.2tex) was used as the warp and weft, and air A plain weave glass fiber fabric having a warp density of 90 threads/25 mm and a weft thread density of 90 threads/25 mm was obtained by weaving with a jet loom. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass fiber fabric were removed by heating at 400° C. for 30 hours. After that, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Corporation) was adjusted to a concentration of 15 g/L and squeezed with a padder roll. After that, it was dried and cured at 120°C for 1 minute. Then, the glass fiber fabric was widened once by water jet processing at a pressure of 1.5 MPa while the tension of the glass fiber fabric was set to 100 N/m in the warp direction to obtain a glass fiber fabric 2. The obtained glass fiber fabric had a warp density of 90/25 mm, a weft density of 90/25 mm, a thickness of 27 μm, a mass of 30 g/m ² , and a refractive index of 1.561.

(Lamination of antistatic layer on film layer 5)
An antistatic layer was laminated on one surface of Cosmoshine (registered trademark) A4300 (thickness: 50 μm) serving as the film layer 5. The antistatic layer is made by adding tin oxide fine particles (average particle diameter 20 nm) in a polyester resin as a binding resin such that the mass ratio of the binding resin to the tin oxide fine particles (fixing resin: tin oxide fine particles) is 75:25. The mixed and dispersed antistatic agent was coated on one side of Cosmoshine (registered trademark) A4300 (thickness: 50 μm) to serve as film layer 5, and then dried. The provided antistatic layer had a mass of 0.5 g/m ² and a thickness of 0.4 μm.

(Lamination of a removable protective film to film layer 5 (antistatic layer side) that is peeled off during use)
On the antistatic layer of Cosmoshine (registered trademark) A4300, which is the film layer 5 and has the antistatic layer on one side, the polypropylene is used as the peelable cover layer that is peeled off during use. A removable protective film that is coated with an acrylic ester adhesive on one side of the film and is laminated with the adhesive facing the antistatic layer, dried, and peeled off during use. A laminate X having a laminate structure of acrylic acid ester adhesive/antistatic layer/Cosmoshine (registered trademark) A4300 as film layer 5 was obtained. Two laminates X were prepared.

(Formation of the first resin layer 3 and lamination of the laminate A including the film layer 5 on the first resin layer 3)
The first resin layer 3 is formed on the Cosmoshine (registered trademark) A4300 side (that is, the side opposite to the peelable cover layer that is peeled off during use) of one laminate A curable resin composition consisting of acrylic syrup was applied. Next, the obtained glass fiber fabric 2 is placed on the curable resin composition which is to be used as the first resin layer 3, and left to stand for 1 minute. It was impregnated with a curable resin composition. Next, the PET film used as the process film described above is placed on the curable resin composition made of the acrylic syrup, and a roller is applied from above the PET film so that the mass of the first resin layer 3 is 25 g/ ^m2 . It was pressurized like this. Thereafter, the curable resin composition made of acrylic syrup, which will become the first resin layer 3, is passed through the PET film in the above step and irradiated with light using a black light fluorescent lamp (product name: FL15BLB, manufactured by Toshiba Corporation) (light irradiation conditions: The curable resin composition is cured with an integrated light amount of 200 mJ/cm ² ) to form the first resin layer 3, and the laminated process PET film is then peeled off to form a peelable film that is peeled off during use. Cover layer/Acrylic acid ester adhesive that can be peeled off together with the cover layer/Antistatic layer/Film layer 5 (Cosmoshine (registered trademark) A4300)/First resin layer impregnated in the glass fiber fabric 2 A laminate Y having the laminate structure of No. 3 was obtained. In the obtained laminate Y, the gaps between the glass fibers of the glass fiber fabric 2 are impregnated with the first resin layer 3 (cured product of the resin composition) made of acrylic syrup without exposing the glass fibers. Ta. Two pieces of the laminate Y were prepared.

(Lamination of the second resin layer 4 contained in the glass fiber fabric 2 in an unimpregnated state)
The second resin layer 4 contained in the glass fiber fabric 2 in an unimpregnated state is formed on the side of the first resin layer 3 impregnated in the glass fiber fabric 2 of the laminate Y obtained above. The brominated vinyl ester resin composition described in 1 was applied. Next, the other of the obtained laminate Y is placed on top of the brominated vinyl ester resin composition, with the first resin layer 3 side of the laminate Y facing the brominated vinyl ester resin composition. Then, pressure was applied from above the other laminate Y using a roller so that the mass of the second resin layer 4 made of the brominated vinyl ester resin composition was 189 g/m ² . Thereafter, the brominated vinyl ester resin composition that is to be the second resin layer 4 is passed through the other laminate Y and irradiated with light (light irradiation conditions : The second resin layer 4 is formed by curing the brominated vinyl ester resin composition with an integrated light amount of 200 mJ/cm ² ), and a removable cover layer that is peeled off during use/acrylic that can be peeled off together with the cover layer. Acid ester adhesive/antistatic layer/film layer 5 (Cosmoshine (registered trademark) A4300)/first resin layer 3 impregnated in glass fiber fabric 2/not impregnated in glass fiber fabric 2 Second resin layer 4 included in the glass fiber fabric 2 / First resin layer 3 included in the impregnated state of the glass fiber fabric 2 / Film layer 5 (Cosmoshine (registered trademark) A4300) / Antistatic layer / Peelable together with the cover layer A transparent sheet 1 of the present invention having a laminated structure of an acrylic ester adhesive/a removable cover layer that is peeled off during use was obtained. Note that the evaluation of the bromine concentration, total light transmittance, haze, total calorific value, and time over 200 kW of the transparent sheet described below is based on the peelable cover layer that is peeled off when using the transparent sheet 1 obtained above and the cover. The peelable acrylic ester adhesive was peeled off along with the layer.

<Example 9>
(Preparation of glass fiber fabric)
The product name "ECC1200 1/0 1.0Z" manufactured by Unitika Glass Fiber Co., Ltd. (average filament diameter 4.5 μm, average number of filaments 100, number of twists 1.0Z, count 4.2tex) was used as the warp and weft, and air A plain weave glass fiber fabric having a warp density of 90 threads/25 mm and a weft thread density of 90 threads/25 mm was obtained by weaving with a jet loom. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass fiber fabric were removed by heating at 400° C. for 30 hours. After that, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Corporation) was adjusted to a concentration of 15 g/L and squeezed with a padder roll. After that, it was dried and cured at 120°C for 1 minute. Then, the glass fiber fabric was widened once by water jet processing at a pressure of 1.5 MPa while the tension of the glass fiber fabric was set to 100 N/m in the warp direction to obtain a glass fiber fabric 2. The obtained glass fiber fabric had a warp density of 90/25 mm, a weft density of 90/25 mm, a thickness of 27 μm, a mass of 30 g/m ² , and a refractive index of 1.561.

(Lamination of antistatic layer on film layer 5)
An antistatic layer was laminated on one surface of Cosmoshine (registered trademark) A4300 (thickness: 50 μm) serving as the film layer 5. The antistatic layer is made by adding tin oxide fine particles (average particle size 20 nm) in a polyester resin as a binding resin such that the mass ratio of the binding resin to the tin oxide fine particles (fixing resin: tin oxide fine particles) is 75:25. The mixed and dispersed antistatic agent was coated on one side of Cosmoshine (registered trademark) A4300 (thickness: 50 μm) to serve as film layer 5, and then dried. The provided antistatic layer had a mass of 0.5 g/m ² and a thickness of 0.4 μm.

(Lamination of a removable protective film to film layer 5 (antistatic layer side) that is peeled off during use)
On the antistatic layer of Cosmoshine (registered trademark) A4300, which is the film layer 5 and has the antistatic layer on one side, the polypropylene is used as the peelable cover layer that is peeled off during use. A removable protective film that is coated with an acrylic ester adhesive on one side of the film and is laminated with the adhesive facing the antistatic layer, dried, and peeled off during use. A laminate X having a laminate structure of acrylic acid ester adhesive/antistatic layer/Cosmoshine (registered trademark) A4300 as film layer 5 was obtained. Two laminates X were prepared.

(Formation of the first resin layer 3 and lamination of the laminate A including the film layer 5 onto the first resin layer 3)
The first resin layer 3 is formed on the Cosmoshine (registered trademark) A4300 side (that is, the side opposite to the peelable cover layer that is peeled off during use) of one laminate A curable resin composition consisting of acrylic syrup was applied. Next, the obtained glass fiber fabric 2 is placed on the curable resin composition which is to be used as the first resin layer 3, and left to stand for 1 minute. It was impregnated with a curable resin composition. Next, the PET film used as the process film described above is placed on the curable resin composition made of the acrylic syrup, and a roller is applied from above the PET film so that the mass of the first resin layer 3 is 25 g/ ^m2 . It was pressurized like this. Thereafter, the curable resin composition made of acrylic syrup, which will become the first resin layer 3, is passed through the PET film in the above step and irradiated with light using a black light fluorescent lamp (product name: FL15BLB, manufactured by Toshiba Corporation) (light irradiation conditions: The curable resin composition is cured with an integrated light amount of 200 mJ/cm ² ) to form the first resin layer 3, and the laminated process PET film is then peeled off to form a peelable film that is peeled off during use. Cover layer/Acrylic acid ester adhesive that can be peeled off together with the cover layer/Antistatic layer/Film layer 5 (Cosmoshine (registered trademark) A4300)/First resin layer impregnated in the glass fiber fabric 2 A laminate Y having the laminate structure of No. 3 was obtained. In the obtained laminate Y, the gaps between the glass fibers of the glass fiber fabric 2 are impregnated with the first resin layer 3 (cured product of the resin composition) made of acrylic syrup without exposing the glass fibers. Ta. Two pieces of the laminate Y were prepared.

(Lamination of the second resin layer 4 contained in the glass fiber fabric 2 in an unimpregnated state)
The second resin layer 4 contained in the glass fiber fabric 2 in an unimpregnated state is formed on the side of the first resin layer 3 impregnated in the glass fiber fabric 2 of the laminate Y obtained above. The brominated vinyl ester resin composition described in 1 was applied. Next, the other of the obtained laminate Y is placed on top of the brominated vinyl ester resin composition, with the first resin layer 3 side of the laminate Y facing the brominated vinyl ester resin composition. Then, pressure was applied from above the other laminate Y using a roller so that the mass of the second resin layer 4 made of the brominated vinyl ester resin composition was 229 g/m ² . Thereafter, the brominated vinyl ester resin composition that is to be the second resin layer 4 is passed through the other laminate Y and irradiated with light (light irradiation conditions : The second resin layer 4 is formed by curing the brominated vinyl ester resin composition with an integrated light amount of 200 mJ/cm ² ), and a removable cover layer that is peeled off during use/acrylic that can be peeled off together with the cover layer. Acid ester adhesive/antistatic layer/film layer 5 (Cosmoshine (registered trademark) A4300)/first resin layer 3 impregnated in glass fiber fabric 2/not impregnated in glass fiber fabric 2 Second resin layer 4 included in the glass fiber fabric 2 / First resin layer 3 included in the impregnated state of the glass fiber fabric 2 / Film layer 5 (Cosmoshine (registered trademark) A4300) / Antistatic layer / Peelable together with the cover layer A transparent sheet 1 of the present invention having a laminated structure of an acrylic ester adhesive/a removable cover layer that is peeled off during use was obtained. Note that the evaluation of the bromine concentration, total light transmittance, haze, total calorific value, and time over 200 kW of the transparent sheet described below is based on the peelable cover layer that is peeled off when using the transparent sheet 1 obtained above and the cover. The peelable acrylic ester adhesive was peeled off along with the layer.

<Example 10>
(Preparation of glass fiber fabric)
The product name "ECC1200 1/0 1.0Z" manufactured by Unitika Glass Fiber Co., Ltd. (average filament diameter 4.5 μm, average number of filaments 100, number of twists 1.0Z, count 4.2tex) was used as the warp and weft, and air A plain weave glass fiber fabric having a warp density of 90 threads/25 mm and a weft thread density of 90 threads/25 mm was obtained by weaving with a jet loom. Then, the spinning sizing agent and the weaving sizing agent adhering to the obtained glass fiber fabric were removed by heating at 400° C. for 30 hours. After that, the surface treatment agent silane coupling agent (S-350: N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride) Chisso Corporation) was adjusted to a concentration of 15 g/L and squeezed with a padder roll. After that, it was dried and cured at 120°C for 1 minute. Then, the glass fiber fabric was widened once by water jet processing at a pressure of 1.5 MPa while the tension of the glass fiber fabric was set to 100 N/m in the warp direction to obtain a glass fiber fabric 2. The obtained glass fiber fabric had a warp density of 90/25 mm, a weft density of 90/25 mm, a thickness of 27 μm, a mass of 30 g/m ² , and a refractive index of 1.561.

(Lamination of antistatic layer on film layer 5)
An antistatic layer was laminated on one surface of Cosmoshine (registered trademark) A4300 (thickness: 50 μm) serving as the film layer 5. The antistatic layer is made by adding tin oxide fine particles (average particle size 20 nm) in a polyester resin as a binding resin such that the mass ratio of the binding resin to the tin oxide fine particles (fixing resin: tin oxide fine particles) is 75:25. The mixed and dispersed antistatic agent was coated on one side of Cosmoshine (registered trademark) A4300 (thickness: 50 μm) to serve as film layer 5, and then dried. The provided antistatic layer had a mass of 0.5 g/m ² and a thickness of 0.4 μm.

(Lamination of a removable protective film to film layer 5 (antistatic layer side) that is peeled off during use)
On the antistatic layer of Cosmoshine (registered trademark) A4300, which is the film layer 5 and has the antistatic layer on one side, the polypropylene is used as the peelable cover layer that is peeled off during use. A removable protective film that is coated with an acrylic ester adhesive on one side of the film and is laminated with the adhesive facing the antistatic layer, dried, and peeled off during use. A laminate X having a laminate structure of acrylic acid ester adhesive/antistatic layer/Cosmoshine (registered trademark) A4300 as film layer 5 was obtained. Two laminates X were prepared.

(Formation of the first resin layer 3 and lamination of the laminate A including the film layer 5 onto the first resin layer 3)
The first resin layer 3 is formed on the Cosmoshine (registered trademark) A4300 side (that is, the side opposite to the peelable cover layer that is peeled off during use) of one laminate A curable resin composition consisting of acrylic syrup was applied. Next, the obtained glass fiber fabric 2 is placed on the curable resin composition which is to be used as the first resin layer 3, and left to stand for 1 minute. It was impregnated with a curable resin composition. Next, the PET film used as the process film described above is placed on the curable resin composition made of the acrylic syrup, and a roller is applied from above the PET film so that the mass of the first resin layer 3 is 25 g/ ^m2 . It was pressurized like this. Thereafter, the curable resin composition made of acrylic syrup, which will become the first resin layer 3, is passed through the PET film in the above step and irradiated with light using a black light fluorescent lamp (product name: FL15BLB, manufactured by Toshiba Corporation) (light irradiation conditions: The curable resin composition is cured with an integrated light amount of 200 mJ/cm ² ) to form the first resin layer 3, and then the laminated process PET film is peeled off to form a peelable film that is peeled off during use. Cover layer/Acrylic acid ester adhesive that can be peeled off together with the cover layer/Antistatic layer/Film layer 5 (Cosmoshine (registered trademark) A4300)/First resin layer impregnated in the glass fiber fabric 2 A laminate Y having the laminate structure of No. 3 was obtained. In the obtained laminate Y, the gaps between the glass fibers of the glass fiber fabric 2 are impregnated with the first resin layer 3 (cured product of the resin composition) made of acrylic syrup without exposing the glass fibers. Ta. Two pieces of the laminate Y were prepared.

(Lamination of the second resin layer 4 contained in the glass fiber fabric 2 in an unimpregnated state)
The second resin layer 4 contained in the glass fiber fabric 2 in an unimpregnated state is formed on the side of the first resin layer 3 impregnated in the glass fiber fabric 2 of the laminate Y obtained above. The brominated vinyl ester resin composition described in 1 was applied. Next, the other of the obtained laminate Y is placed on top of the brominated vinyl ester resin composition, with the first resin layer 3 side of the laminate Y facing the brominated vinyl ester resin composition. Then, pressure was applied from above the other laminate Y using a roller so that the mass of the second resin layer 4 made of the brominated vinyl ester resin composition was 269 g/m ² . Thereafter, the brominated vinyl ester resin composition that is to be the second resin layer 4 is passed through the other laminate Y and irradiated with light (light irradiation conditions : The second resin layer 4 is formed by curing the brominated vinyl ester resin composition with an integrated light amount of 200 mJ/cm ² ), and a removable cover layer that is peeled off during use/acrylic that can be peeled off together with the cover layer. Acid ester adhesive/antistatic layer/film layer 5 (Cosmoshine (registered trademark) A4300)/first resin layer 3 impregnated in glass fiber fabric 2/not impregnated in glass fiber fabric 2 Second resin layer 4 included in the glass fiber fabric 2 / First resin layer 3 included in the impregnated state of the glass fiber fabric 2 / Film layer 5 (Cosmoshine (registered trademark) A4300) / Antistatic layer / Peelable together with the cover layer A transparent sheet 1 of the present invention having a laminated structure of an acrylic ester adhesive/a removable cover layer that is peeled off during use was obtained. Note that the evaluation of the bromine concentration, total light transmittance, haze, total calorific value, and time over 200 kW of the transparent sheet described below is based on the peelable cover layer that is peeled off when using the transparent sheet 1 obtained above and the cover. The peelable acrylic ester adhesive was peeled off along with the layer.

In addition, in the examples, the weaving density of the glass fiber fabric was measured and calculated in accordance with JIS R 3420 2013 7.9. Moreover, the thickness of the glass fiber fabric was measured and calculated according to JIS R 3420 2013 7.10.1A method. The mass of the glass fiber fabric was measured and calculated in accordance with JIS R 3420 2013 7.2. The refractive index of the glass fiber fabric 2, the first resin layer 3, and the second resin layer 4 was measured and calculated by the method described above. The Abbe numbers of the glass fiber fabric 2 and the first resin layer 3 were measured and calculated using the method described above. The following evaluations were performed after the transparent sheet 1 was left indoors for one week after it was produced.

Bromine concentration was measured and calculated using the method described above.

Total light transmittance and haze of the transparent sheet 1 after peeling off the peelable cover layer that is peeled off during use, and Building Materials Testing Center, General Incorporated Foundation The surface of the sheet from the radiant electric heater is measured in accordance with ``4.10.2 Heat generation test and evaluation method'' in the ``Fireproof performance test and evaluation work method manual'' (revised version on March 1, 2014). In the exothermic test in which 50 kW/m ² of radiant heat was irradiated, the total calorific value (MJ/m ² ) and the time (S) during which the heat generation rate exceeded 200 kW/m ² were measured and calculated using the method described above. In addition, the presence or absence of through holes was determined for the sheet 20 minutes after the start of heating according to the above-mentioned "4.10.2 Heat generation test/evaluation method".

The results of each evaluation are shown in Tables 1 and 2.

As is clear from Tables 1 and 2, the transparent sheets of Examples 1 to 10 are transparent sheets containing a plain-woven glass fiber fabric and a resin, and the glass fiber fabric is attached to the glass fiber fabric in the thickness direction of the transparent sheet. a first resin layer included in an impregnated state and a second resin layer included in an unimpregnated state in the glass fiber fabric, the bromine concentration of the second resin layer being higher than the bromine concentration of the first resin layer; , The total light transmittance of the transparent sheet is 85% or more and the haze is 10% or less. Therefore, when the resin weight is increased, the transparency can be improved and the total calorific value can be lowered. This made it possible to achieve a better balance between the two.

Among them, the transparent sheets of Examples 7 to 10 contain tetrabromobisphenol A, decabromodiphenyl ether, or brominated vinyl ester in the first resin layer, so Example 1 in which the first resin layer contains phosphorus -6, "4.10.2 Pyrogenicity test and evaluation method" in the "Fireproof performance test and evaluation work method manual" (revised version on March 1, 2014) of the Building Materials Testing Center, a general incorporated foundation. In a heat generation test in which the surface of the sheet is irradiated with 50 kW/ ^m2 of radiant heat from a radiant electric heater, blistering of the first resin layer is less likely to occur, and for 20 minutes after the start of heating due to the blistering, fire prevention Harmful cracks and holes penetrating to the back surface were less likely to occur.

1... Transparent sheet 2... Glass fiber fabric 3... First resin layer 4... Second resin layer 5... Film layer

Claims (7)

A transparent sheet comprising a plain weave glass fiber fabric and a resin,
In the thickness direction of the transparent sheet, a first resin layer included in the glass fiber fabric is impregnated, and a second resin layer is included in the glass fiber fabric in a non-impregnated state,
The first resin layer is laminated on both sides of the second resin layer, respectively,
The bromine concentration of the second resin layer is higher than the bromine concentration of the first resin layer,
The transparent sheet has a total light transmittance of 85% or more and a haze of 10% or less,
Transparent sheet. Radiation measured in accordance with "4.10.2 Heat generation test and evaluation method" in the "Fireproof performance test and evaluation work method manual" (revised version on March 1, 2014) of the Building Materials Testing Center, a general incorporated foundation. The transparent sheet according to claim 1 , which has a total calorific value of 8 MJ/m ² or less in a heat generation test in which the surface of the sheet is irradiated with 50 kW/m ² radiant heat from an electric heater. The transparent sheet according to claim 1 or 2 , wherein the first resin layer is laminated on both surfaces of the second resin layer. The transparent sheet according to any one of claims 1 to 3 , wherein the total content of resins contained in the first resin layer and the second resin layer is 200 g/m ² or more. The transparent sheet according to any one of claims 1 to 4 , wherein the total thickness of the first resin layer and the second resin layer is 180 μm or more. The transparent sheet according to any one of claims 1 to 5 , wherein the second resin layer contains a brominated vinyl ester resin. The transparent sheet according to claim 6 , wherein the first resin layer contains tetrabromobisphenol A.

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