JP2019059140A - Transparent nonflammable sheet - Google Patents

Abstract

To provide a transparent nonflammable sheet that is a sheet formed of a glass fiber fabric combined with a thermoplastic resin, which prevents whitened flaws inside of the sheet even when repeating bending and folding of the sheet, is excellent in flexibility and can maintain transparency for a long period of time.SOLUTION: A transparent nonflammable sheet is formed by laminating an intermediate layer formed by impregnating a glass fiber fabric with a styrene thermoplastic elastomer, and vinyl chloride resin film layers laminated on both surfaces of the intermediate layer.SELECTED DRAWING: None

Description

  The present invention relates to a transparent noncombustible sheet using a glass fiber cloth and a thermoplastic resin, and more particularly to a transparent noncombustible sheet excellent in suppression of generation of whitening scratches due to sheet bending and folding and long-term transparency maintenance.

A non-combustible sheet is a non-combustible material defined by the Building Standard Law and the Building Standard Law Construction Order, and in the heat generation test, the total calorific value for 20 minutes after the start of heating is 8 MJ / m ² or less, and The requirement is that the maximum heating rate for 20 minutes after the start of heating does not continue beyond 200 kW / m ² and continues for 10 seconds or more, and there is no through hole after combustion.

As such a noncombustible sheet, a glass fiber material or a composite sheet of a glass fiber cloth and a resin is known and can be used as a building material.
For example, a smoke-proof hanging wall installed on the ceiling of a building to prevent the flow and diffusion of smoke during fires, a partition curtain for partitioning the work area in the factory, a film ceiling for transmitting the light intensity of the light source directly into the space, There is an increasing demand for highly transparent materials that are used as illumination film covers.

Thermosetting resins and vinyl chloride resins are mainly used as the resin to be composited with the glass fiber cloth.
For example, Patent Document 1 discloses a transparent noncombustible sheet comprising a woven glass fiber and a cured resin layer such as a vinyl ester resin, and Patent Document 2 comprises a glass fiber base material impregnated and coated with a soft vinyl chloride resin composition. Transparent composite sheets have been proposed.

In the case of using a thermosetting resin as in Patent Document 1, since the viscosity is low in an uncured state, it is easy to impregnate into glass fiber fabric, and the difference in refractive index between glass fiber and curable resin is 0.02 or less. By setting the difference in Abbe number to 30 or less, a non-combustible sheet excellent in transparency can be obtained. However, to form a cured resin layer, the apparatus and process are relatively complicated, and the cost is high.
In addition, when the non-combustible sheet is folded or folded, a state in which whitening scratches occur inside the sheet is often observed. The whitening flaw is a state in which the gap is not restored but refracted and irregularly reflected because the gap is generated due to the fine peeling between the interface of the thermosetting resin and the glass fiber fabric or the fibers of the glass fiber fabric. It looks like a whitened scratch. In particular, since the thermosetting resin is difficult to stretch, it can not follow the glass fiber fabric and is prone to whitening scratches. Therefore, non-combustible sheets using a thermosetting resin are not suitable for applications requiring flexibility.
Furthermore, such noncombustible sheets need to have a large area depending on the application, and generally, the width connection of sheets is performed by sewing or thermal welding, but it is easy with thermosetting resins. There is also a problem that the width of the sheet can not be connected by heat welding.

Further, Patent Document 2 discloses adjusting the refractive index by causing the vinyl chloride resin to contain a large amount of an aromatic phosphoric acid ester compound which is a kind of plasticizer as a refractive index adjusting agent. Thereby, the difference of the refractive index of vinyl chloride resin and glass fiber can be made small, and transparency can be ensured.
However, in such a sheet containing a plasticizer in a resin, the plasticizer migrates to the surface (bleeds out) with time, and the stickiness of the surface increases, and dust and the like are adsorbed and easily contaminated, which is handled. Was difficult. Moreover, in the case of a sheet formed by impregnating and applying the soft vinyl chloride resin to a base material made of glass fiber, the sheet peels off due to insufficient adhesion between the glass fiber and the soft vinyl chloride resin, and when bending and folding are repeated Blemishes tended to occur.

Therefore, in Patent Document 3, an adhesive-impregnated glass cloth obtained by impregnating and coating an adhesive component containing a non-aromatic triisocyanate compound and a binder resin on a glass cloth substrate, and a soft vinyl chloride resin transparent layer are provided on both sides thereof. Transparent noncombustible sheets have been proposed.
The said glass cloth base material shall be surface-treated by the silane coupling agent, and the said silane coupling agent and the triisocyanate compound of an adhesive agent react, and the inside of the sheet by the bending or folding of a sheet | seat is carried out. It is disclosed that a sheet can be obtained which does not easily cause whitening scratches. Further, by providing the soft vinyl chloride resin transparent layer on both sides, since the heat welding property is also excellent, the sheet width connection is also possible.

  However, the soft vinyl chloride resin transparent layer contains an aromatic phosphoric acid ester compound as a plasticizer, but the phosphoric acid ester compound and the binder resin are transparent to the soft vinyl chloride resin from the adhesive-impregnated glass cloth as time passes. It moves to the layer and causes bleeding. Therefore, there is a problem that the difference in refractive index between the glass cloth and the adhesive component becomes large, and the transparency decreases with time.

  In order to suppress the bleeding out of the plasticizer from such an impregnated layer, in Patent Document 4, as a plasticizer contained in a vinyl chloride resin composition to be impregnated into a glass fiber fabric, one having a molecular weight of more than 420 is used. Although measures such as use were examined, it has not been able to completely ameliorate the problem of the transparency fall over time.

JP, 2005-319746, A JP, 2010-052370, A JP, 2014-076563, A JP 2015-077756

  Therefore, even if the sheet of the present invention is a sheet made of a glass fiber cloth compounded with a thermoplastic resin, the sheet is excellent in flexibility without whitening scratches even if the sheet is repeatedly folded or folded. An object is to provide a transparent noncombustible sheet capable of maintaining transparency for a long time.

  As a result of investigations to solve the above problems, the present inventors used styrene-based thermoplastic elastomer as a thermoplastic resin to be impregnated into a glass fiber fabric, and as a result, it is possible to prevent the impregnation resin from containing a plasticizer and to obtain a refractive index. And flexibility can be adjusted, and the impregnation with the glass fiber cloth is good, and whitening scratches do not occur inside the sheet even if the sheet composited with the glass fiber cloth is repeatedly folded or folded In the present invention.

  That is, the present invention is characterized in that an intermediate layer formed by impregnating a glass fiber fabric with a styrene thermoplastic elastomer and a vinyl chloride resin film layer are laminated on both sides of the intermediate layer.

  In the present invention, since a styrenic thermoplastic elastomer is used, the refractive index and the flexibility can be adjusted without including a plasticizer in the resin impregnated in the glass fiber cloth, and the transparency is long-termed. It can be maintained. Furthermore, since a styrenic thermoplastic elastomer is excellent in the impregnating ability to a glass fiber cloth and the adhesiveness with a vinyl chloride resin film layer, even if the sheet is repeatedly bent or folded, a whitening scratch is generated inside the sheet. It is possible to obtain a transparent noncombustible sheet which is excellent in flexibility and can maintain transparency for a long time.

  Moreover, it is preferable that the refractive index difference of glass fiber and a styrene-type thermoplastic elastomer is 0.03 or less. If the refractive index difference is 0.03 or less, the glass fiber cloth becomes inconspicuous, and a transparent noncombustible sheet with high transparency can be obtained.

  Further, in the present invention, the sheet having excellent transparency preferably has a total light transmittance of 80% or more and a haze of 30% or less.

Furthermore, the styrenic thermoplastic elastomer is a hydrogenated styrenic thermoplastic elastomer, and the SP value of the hydrogenated butadiene portion is 17.5 (J / cm ³ ) ^1/2 or more. Do.

  If it is the range of the said SP value, since the impregnatability to a glass fiber cloth will improve, transparency will also increase and it can further suppress generation | occurrence | production of the whitening flaw by bending or folding. In addition, since the adhesion between the vinyl chloride resin film layer and the intermediate layer is also improved, it does not peel off and the flexibility is not impaired.

  The present invention is a transparent noncombustible sheet obtained by laminating an interlayer comprising a glass fiber fabric impregnated with a styrenic thermoplastic elastomer, and a vinyl chloride resin film layer on both surfaces of the interlayer, the styrenic thermoplastic elastomer By using the above, the refractive index and the flexibility can be adjusted without containing a plasticizer in the resin to be impregnated into the glass fiber fabric, and the transparency can be maintained for a long time. Furthermore, since the styrenic thermoplastic elastomer is excellent in the impregnating ability to the glass fiber fabric and the adhesion to the vinyl chloride resin film layer, the transparent noncombustible sheet of the present invention whitens inside the sheet even if it is repeatedly bent and folded. It is excellent in flexibility without causing scratches.

  The present invention is a transparent noncombustible sheet characterized in that an intermediate layer formed by impregnating a glass fiber fabric with a thermoplastic resin and a vinyl chloride resin film layer are laminated on both sides of the intermediate layer.

The intermediate layer of the present invention will be described.
The intermediate layer is formed by impregnating a glass fiber fabric with a thermoplastic resin, but in order to impart transparency, it is necessary to use a resin having a small difference in refractive index from the glass fiber of the glass fiber fabric. So, in this invention, a styrene-type thermoplastic elastomer is used as resin which adjustment of refractive index is easy.

  Examples of styrenic thermoplastic elastomers include block copolymers of styrenic monomers and butadiene (SBS), block copolymers of styrenic monomers and isoprene (SIS), styrene obtained by hydrogenating the double bond part of SBS. Ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS) obtained by hydrogenating double bond part of SIS, etc. can be used, and hydrogenated styrene system It is preferable to use a thermoplastic elastomer (hereinafter referred to as a hydrogenated styrenic thermoplastic elastomer). Further, the hydrogenation rate is preferably 90% or more, and more preferably completely hydrogenated.

Examples of the styrene-based monomer include styrene, α-methylstyrene, p-methylstyrene, N, N-dimethyl-p-aminoethylstyrene, N, N-diethyl-p-aminoethylstyrene, etc. From the aspect, styrene or α-methylstyrene is preferred. These styrenic monomers may be used alone or in combination of two or more.
On the other hand, examples of butadiene include 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), etc. 3-Butadiene is preferred. These butadiene-based monomers may be used alone or in combination of two or more.

  The styrenic thermoplastic elastomer is provided with a styrene block region (hard segment) which imparts strength and an ethylene / butylene region (soft segment) which imparts rubber elasticity behavior, and variously by adjusting the composition etc. Have the following characteristics. For example, it is excellent in heat resistance, weather resistance, transparency, conformability to other resins, and can provide the same flexibility as a soft vinyl chloride resin. In particular, a hydrogenated styrene-based thermoplastic elastomer obtained by hydrogenating a double bond portion is excellent in weather resistance.

Further, the styrene-based thermoplastic elastomer can be adjusted in refractive index by the composition of the hard segment and the soft segment without adding an additive such as a plasticizer like a vinyl chloride resin. Therefore, when the glass fiber fabric is impregnated, the difference in refractive index with the glass fiber becomes large due to the bleeding out of the plasticizer from the intermediate layer, the transparency does not decrease with time, and the transparency can be maintained for a long time .
In the present invention, those having a refractive index adjusted in the range of 1.53 to 1.59 can be used. Within this range, since the refractive index of the general-purpose glass fiber (E glass) is about 1.56 on average, the difference in refractive index can be made small.
The difference in refractive index between the styrene-based thermoplastic elastomer and the glass fiber is preferably 0.03 or less, more preferably 0.02 or less. If the refractive index difference is 0.03 or less, the glass fiber cloth becomes inconspicuous and a highly transparent incombustible sheet can be obtained.

  In addition, a refractive index is calculated | required based on JISK7142, and if it is a substance with near refractive index, it is excellent in transparency.

In addition, the styrenic thermoplastic elastomer can also adjust the flexibility by the composition of the hard segment and the soft segment, etc., and the intermediate layer impregnated with the glass fiber fabric is excellent in flexibility so as to be able to follow the deformation of the glass fiber fabric. It is a thing.
In addition, since the styrenic thermoplastic elastomer is excellent in the impregnating ability to the glass fiber cloth, even if the intermediate layer is repeatedly bent or folded, the interface between the styrenic thermoplastic elastomer and the glass fiber cloth and the fineness between the glass fibers are fine. There is no occurrence of a gap due to peeling, and the occurrence of whitening flaws inside the sheet can be suppressed.

In particular, in the hydrogenated styrenic thermoplastic elastomer, it is preferable that the SP value in the hydrogenated butadiene portion is 17.5 (J / cm ³ ) ^1/2 or more. Within this range, the compatibility with the resin and the inorganic material having high polarity and the wettability are excellent.
If the hydrogenated styrene thermoplastic elastomer is used in the intermediate layer, the impregnating ability to the glass fiber fabric is improved, the transparency is also increased (the haze value is reduced), and the generation of the whitening flaw due to bending or folding is further suppressed it can. Moreover, it is excellent also in the adhesiveness with the vinyl chloride resin film layer mentioned later.

Here, the solubility parameter (SP value, Solubility Parameter) is used to evaluate the solubility, adhesion or wettability to other substances. The SP value is calculated from the equation of (molar aggregation energy (J / mol) / molar volume (10 ⁻⁶ m ³ / mol)) ^1/2 .

  In the present invention, the glass transition temperature (Tg) of the styrene-based thermoplastic elastomer is preferably in the range of -55 to 30 ° C, and more preferably -20 to 20 ° C. Further, by being in this range, the adhesion to a vinyl chloride resin film is also enhanced, and a sheet having high flexibility is obtained.

  In the present invention, as the glass fiber cloth impregnated with the styrenic thermoplastic elastomer, cloth such as woven cloth, knitted cloth, or non-woven cloth composed of warp and weft consisting of glass fibers can be used.

As glass fiber which comprises a glass fiber cloth, well-known glass fiber can be used, For example, general-purpose alkali free glass fiber (E glass), acid resistance alkali-containing glass fiber (C glass), alkali resistant glass fiber (AR glass), glass fiber with high strength and high elastic modulus (S glass, T glass), and the like.
Among them, E glass is preferable in terms of versatility and a difference in refractive index with a styrene-based thermoplastic elastomer, and S glass and T glass are preferable in terms of flexibility.

  Moreover, as for the glass fiber which comprises a glass fiber cloth, it is preferable that the diameter of a filament is the range of 4-7 micrometers. By setting the diameter of the glass fiber in the above range, the strength of the fiber fabric is good, and the impregnation of the styrenic thermoplastic elastomer into the fibers is good.

Furthermore, as for the glass fiber cloth, it is preferable that the glass fiber which comprises a glass fiber cloth is surface-treated by the silane coupling agent etc. Specific examples thereof include vinylsilane, phenylsilane, epoxysilane, acrylic silane, aromatic aminosilane and aliphatic aminosilane, and preferably aromatic aminosilane can be used.
By the surface treatment of the glass fiber, the impregnation with the styrenic thermoplastic elastomer can be enhanced, and good transparency can be maintained, and at the time of bending or the like, the glass fiber and the styrenic thermoplastic elastomer can be used. It is possible to suppress the occurrence of whitening scratches inside the sheet due to the peeling of

Moreover, it is preferable that a glass fiber cloth is 20-60 g / m < ² > in fabric weight.
If the basis weight of the glass fiber fabric is less than 20 g / m ² , impregnation of the styrenic thermoplastic elastomer is well performed, but the strength of the sheet may be low or deformation may occur during processing. On the other hand, when the basis weight exceeds 60 g / m ² , it is difficult to impregnate the resin between glass fibers, and the transparency of the transparent noncombustible sheet may be reduced.

Furthermore, in the glass fiber fabric, it is preferable that a gap between fiber bundles of adjacent warps constituting the glass fiber fabric and a gap between fiber bundles of adjacent warps be 0.5 mm or less. When the gap | interval beyond the said range exists, there exists a possibility that nonflammability may become difficult to be obtained.
In this case, the yarn density and the weft density are preferably 60 yarns / 2.54 cm or more, and the gap between the fiber bundles can be 0.5 mm or less, and excellent nonflammability can be maintained.

In the intermediate layer of the present invention, the adhesion amount of the styrenic thermoplastic elastomer to the glass fiber fabric is not particularly specified, but 10 to 90 g / m ^{2 in} a dry state is preferable, and 30 to 90 g / m ² is more preferable. preferable. When the adhesion amount is too small, it is difficult to obtain good transparency, and when the adhesion amount is too large, nonflammability can not be obtained.

In the present invention, the impregnating property is evaluated using a digital microscope with a value calculated by calculating the area of the luminance extraction area, for the area ratio of the portion where the glass fiber is seen without being impregnated with the resin. The area ratio is preferably less than 20%.
In addition, the white portion of the glass fiber is visually recognized in the portion where the glass fiber is not impregnated, and the difference in brightness with the portion (transparent) where the glass fiber is impregnated is generated. You can ask for

  The intermediate layer may contain other additives as necessary except for the one having the bleeding property. For example, pigments for coloring, inorganic fillers, flame retardants, lubricants, heat stabilizers, antioxidants, ultraviolet absorbers, light diffusers, other resins, etc. may be mentioned.

Next, the vinyl chloride resin film layer of the present invention will be described.
In the present invention, a vinyl chloride resin film layer is laminated on both sides of the intermediate layer. By providing the said vinyl chloride resin film layer, while improving a noncombustibility, the width connection of the sheet | seat by heat weldability is attained.
Further, in order to obtain a transparent noncombustible sheet, the vinyl chloride resin film layer is preferably transparent. Specifically, the total light transmittance is 90% or more and the haze value is 5% or less.

In the present invention, the vinyl chloride resin is not particularly limited, but for example, a flexible vinyl chloride resin containing a plasticizer can be used.
The amount of the plasticizer added is preferably 15 to 40% by weight based on the weight of the film, and while maintaining the flexibility, it is possible to suppress the stickiness of the sheet surface due to bleed out. In addition, even if it contains a plasticizer in a vinyl chloride resin film layer, transparency as a noncombustible sheet does not fall, and it has not been confirmed also over time.
Furthermore, additives such as a flame retardant, an ultraviolet absorber, a filler, an antistatic agent, and a coloring agent may be included within the range not impairing the effects of the present invention.

The surface of the vinyl chloride resin film layer may be subjected to surface treatment according to the purpose such as blocking prevention and antistatic prevention.
Also, although the vinyl chloride resin film and the styrene-based thermoplastic elastomer impregnated in the intermediate layer are excellent in adhesion, in order to further improve the adhesion, the surface of the vinyl chloride resin film in contact with the intermediate layer is also surface-treated You may

  Although the thickness in particular of a vinyl chloride resin film layer is not restrict | limited, 0.05-0.2 mm is preferable by each layer, More preferably, it is 0.08-0.15 mm. If it is thicker than 0.2 mm, the non-combustibility decreases. If it is less than 0.05 mm, the unevenness of the glass fiber fabric affects the surface of the vinyl chloride film and the visibility is reduced.

  The present invention is a transparent incombustible sheet excellent in flexibility, which is formed by laminating vinyl chloride resin film layers on both sides of an intermediate layer, and does not cause whitening scratches inside the sheet even if bending and folding are repeated.

In the present invention, the transparency is evaluated by the total light transmittance and the haze value measured using a haze meter.
The incombustible sheet of the present invention has a total light transmittance of 80% or more, more preferably 90% or more. It has high transparency by having a transmittance of 80% or more. For example, when used as a curtain for disaster prevention, the opposite side of the sheet can be visually recognized, and when hung on a ceiling with a flame-proof hanging wall, There is no excessive reduction in the brightness of lighting and the like.
The haze value is preferably 30% or less, more preferably 20% or less. When the haze value is within the above range, the visibility on the opposite side of the obtained sheet is improved.
Furthermore, in the present invention, when the haze value after the accelerated test at 40 ° C. for 8 weeks is measured, the rate of change from before the accelerated test is less than 10%, and no change with time of transparency is observed.

In addition, the present invention performs a heat generation test with a corn calorimeter based on Building Standard Act Article 2, Item 9 and Building Standard Act Enforcement Order Article 108-2, and the maximum heating rate after the start of heating is 10 seconds. Continuously, it does not exceed 200 kW / m ² and the total calorific value satisfies the requirement of 8 MJ / m ² or less, and has nonflammability.

In the present invention, the flexibility is evaluated by using the MIT folding endurance tester and the number of times until whitening scratches occur inside the sheet at the time of repeated bending.
The sheet of the present invention exhibits high flexibility because whitening scratches do not occur inside the sheet even if bending is repeated 50 times or more under a load of 9.8 N, an angle of 135 °, and a speed of 175 times / min. The In addition, even if the transparent non-combustible sheet falls from the installation site at the time of disaster etc., it does not break and is unlikely to cause an injury due to fragments etc., so it is possible to apply to the smoke-proof hanging wall.

The manufacturing method of the present application will be described.
The incombustible sheet of the present invention is produced by (1) producing an intermediate layer, and (2) laminating a vinyl chloride resin film layer on the intermediate layer.

(1) Step of Producing Intermediate Layer The intermediate layer is produced by impregnating a glass fiber fabric with a styrenic thermoplastic elastomer.
As the impregnation method, a solution impregnation method can be used.
First, it is dissolved and diluted to a predetermined concentration with a predetermined solvent to prepare a styrenic thermoplastic elastomer solution (impregnation solution), and the glass fiber fabric is dipped. At this time, additives may be added to the impregnating solution as required.
Then, after the glass fiber fabric is sufficiently impregnated with the impregnating solution, the glass fiber fabric is taken out, rolled after squeezing to squeeze out excess solution, or while squeezing the roll, while removing excess solution by its own weight, It is heated and dried at a predetermined temperature to obtain an intermediate layer.

  Cyclohexane, toluene, xylene, tetrahydrofuran (THF), chloroform etc. can be used as a solvent used when dissolving a styrene-type thermoplastic elastomer, Among them, toluene is preferable from the viewpoint of working efficiency.

The concentration of the impregnating solution is preferably 10 to 30% by weight. When the concentration is less than 10% by weight, although the solution is easily impregnated into the glass fiber fabric, the amount of resin adhesion tends to be small, and it may be difficult to obtain predetermined transparency. On the other hand, when it exceeds 30% by weight, the viscosity of the solution becomes high, and it becomes difficult to impregnate the glass fiber woven solution with the solution, which may lower the transparency and the production efficiency.
Under the present circumstances, when it is set as 50-2500 cps as a viscosity of the said impregnation liquid, it is preferable in the surface of an impregnation and resin adhesion amount.

  As another impregnation method, a film coated with a styrenic thermoplastic elastomer solution which is dissolved and diluted to a predetermined concentration with a predetermined solvent and made into a paste is laminated on both sides of a glass fiber fabric and thermocompression bonded to a resin The intermediate layer can be obtained by impregnating and heating and drying at a predetermined temperature and then peeling off the film.

  Further, the transparent non-combustible sheet obtained by the solution impregnation method may be treated with a heat press or the like to improve surface smoothness.

(2) Step of laminating a vinyl chloride resin film layer on the intermediate layer A vinyl chloride resin film prepared in advance is laminated on both sides of the intermediate layer to be integrated. Although it does not specifically limit as a method to unify, The method to adhere | attach by thermocompression bonding without using an adhesive agent is preferable.

The incombustible sheet of the present invention comprises an interlayer formed by impregnating a glass fiber fabric with a styrene-based thermoplastic elastomer, and a vinyl chloride resin film layer on both surfaces of the interlayer, and a styrene-based thermoplastic elastomer is used. Thus, the refractive index and the flexibility can be adjusted without including a plasticizer in the resin to be impregnated into the glass fiber fabric, the transparency does not decrease with time, and the transparency can be maintained for a long time. Furthermore, since styrenic thermoplastic elastomers are excellent in impregnating ability to glass fiber cloth and adhesiveness to a vinyl chloride resin film layer, even if the sheet is repeatedly bent or folded, whitening scratches are generated inside the sheet. No, it is excellent in flexibility.
In particular, by using a hydrogenated styrenic thermoplastic elastomer having an SP value of 17.5 (J / cm ³ ) ^1/2 or more of a hydrogenated butadiene portion, the impregnating ability to a glass fiber fabric is improved. The transparency is also increased (the haze value is reduced), and the occurrence of whitening scratches due to bending or folding can be further suppressed. Moreover, it is excellent in adhesiveness with a vinyl chloride resin film layer, does not peel, and does not impair flexibility.
And since the vinyl chloride resin film layer is provided in the both surfaces of the intermediate | middle layer, a heat welding process becomes possible and sheet width connection is easy.

  Hereinafter, the present invention will be described using examples, but the present invention is not limited thereto.

Example 1
A solution was prepared by dissolving styrenic thermoplastic elastomer A in a toluene solvent to a solid content of 20% by weight, and the solution was surface-treated with an aromatic aminosilane to give a glass with a thickness of 29 μm and a basis weight of 31.5 g / m ² The fiber woven fabric (E glass fiber, refractive index 1.558) was immersed. At this time, the adhesion amount of resin was 150 g / m ^{2 in the} wet state.
Next, in order to evaporate the solvent, it was dried in an oven at 130 ° C. for 5 minutes to obtain a resin-impregnated glass fiber woven fabric (intermediate layer). The resin adhesion amount of the obtained intermediate layer was 30 g / m ^{2 in} a dry state, and the thickness was 0.05 mm.
Furthermore, both sides of the intermediate layer are sandwiched between two 120 μm thick vinyl chloride resin films (manufactured by Achilles, trade name “Achilles Furare”), and the condition of temperature 120 ° C., pressure 10 kg / cm ² , time 5 minutes with a press And pressed to obtain a transparent noncombustible sheet having a thickness of 0.29 mm.
In addition, what contained 29.5 weight% of plasticizers was used for the vinyl chloride resin film.

Example 2
A transparent noncombustible sheet was obtained in the same manner as in Example 1 except that the resin to be impregnated into the glass fiber cloth was changed to a styrene thermoplastic elastomer B.

[Example 3]
A transparent noncombustible sheet was obtained in the same manner as in Example 1 except that the resin to be impregnated into the glass fiber cloth was changed to a styrene thermoplastic elastomer C.

Example 4
A transparent noncombustible sheet was obtained in the same manner as in Example 1 except that the resin to be impregnated into the glass fiber cloth was changed to a styrene thermoplastic elastomer D.

[Example 5]
A transparent noncombustible sheet was obtained in the same manner as in Example 1 except that the resin to be impregnated into the glass fiber cloth was changed to a styrene thermoplastic elastomer E.

Comparative Example 1
4 parts by weight of a curing agent (benzoyl peroxide) and 25 parts by weight of a styrene monomer are added to 100 parts by weight of a vinyl ester resin (Nippon Yupika Co., Ltd., trade name "Neopol 8125"), and the resin composition is stirred for 30 minutes The object was made. In this resin composition, a glass fiber woven fabric (E glass fiber, refractive index 1.558) having a thickness of 29 μm and a basis weight of 31.5 g / m ² surface-treated with acrylic silane was immersed for 30 minutes.
Then, sandwich both sides of the glass fiber woven fabric impregnated with the resin solution with two 100 μm thick polyethylene terephthalate films, remove air bubbles with a roller, and hold in an oven at 100 ° C. for 10 minutes to cure the resin. The After curing of the resin, the polyethylene terephthalate film was peeled off to obtain a resin-impregnated glass fiber woven fabric (intermediate layer). The resin adhesion amount of the obtained intermediate layer was 31 g / m ^{2 in} a dry state, and the thickness was 0.05 mm.
Then, two sheets of 120 μm-thick vinyl chloride resin film were bonded to both surfaces of the obtained intermediate layer using a urethane adhesive to obtain a 0.29 mm-thick transparent noncombustible sheet.

Comparative Example 2
To 100 parts by weight of polyvinyl chloride resin, add 200 parts by weight of phosphoric acid torque resin, 50 parts of di-2-ethylhexyl phthalate, 2 parts of zinc stearate, and 2 parts of barium stearate, and stir for 30 minutes, A resin composition was produced. In this resin composition, a glass fiber woven fabric (E glass fiber, refractive index 1.558) having a thickness of 29 μm and a basis weight of 31.5 g / m ² surface-treated with an aromatic aminosilane was immersed.
Next, gelation was performed by heat treatment at 180 ° C. for 1 minute to obtain a resin-impregnated glass fiber woven fabric (intermediate layer). The resin adhesion amount of the obtained intermediate layer was 30 g / m ^{2 in} a dry state, and the thickness was 0.05 mm.
Then, both sides of the obtained intermediate layer are sandwiched between two vinyl chloride resin films, and pressed with a press at a temperature of 120 ° C. and a pressure of 10 kg / cm ² for 5 minutes, and a transparent noncombustible sheet with a thickness of 0.29 mm I got

  The following evaluation was performed regarding the sheet | seat obtained by Examples 1-5 and Comparative Examples 1 and 2. The results are shown in Table 1.

〔transparency〕
Using a haze meter (manufactured by Suga Test Instruments Co., Ltd., trade name "HZ-V3"), the total light transmittance and the haze value were measured to evaluate the transparency of the sheet.
The transparent noncombustible sheet of the present invention has a total light transmittance of 80% or more and a haze value of 30% or less.

[Impregnability]
The sample is observed at a magnification of 200 times using a digital microscope (trade name "VHX-5000" manufactured by KEYENCE CORPORATION), and the glass fiber can be seen without being impregnated with the resin for the entire area of 2.4 mm ² The area ratio of the part was calculated by area calculation of the luminance extraction area, and was evaluated by the following criteria.

:: less than 10% :: 10% or more and less than 15% :: 15% or more and less than 20% ×: 20% or more

[Maintaining transparency]
The transparent noncombustible sheet immediately after preparation was placed in a dryer for the purpose of verifying the change with time of transparency, and an accelerated test for 8 weeks was conducted at 40 ° C. The haze value of the sheet after the accelerated test was measured.
When the rate of change in haze value before and after the acceleration test is 10% or more, the transparency over time can not be maintained, and the one with less than 10% is regarded as ○.

[Flexibility]
Using a sample cut to 15 mm x 110 mm using a MIT folding endurance tester (tester industry Ltd., trade name "BE-202S"), load 9.8 N, angle 135 °, speed 175 times / min After repeated bending under the following conditions, the bending location was observed, and the number of times until whitening scratches occurred was evaluated according to the following criteria.

○: 100 times or more Δ: 50 times or more and less than 100 times ×: less than 50 times

〔Non Flammable〕
Using each sheet, a heat generation test was conducted using a corn calorimeter based on Building Standard Act Article 2, Item 9, and Building Standard Act Enforcement Order Article 108-2. The maximum heat generation rate after the start of heating does not exceed 200 kW / m ² continuously for 10 seconds or more, and the total heat generation amount is 8 MJ / m ² or less.

Styrene-based thermoplastic elastomer used in the examples:
A: SEBS (manufactured by Asahi Kasei Chemicals Corporation, trade name "S.O.E.S. 1605")
SP value of hydrogenated butadiene part (hereinafter referred to as SP value)
17.5 (J / cm ³ ) ^1/2 or more, refractive index 1.559, Tg 18 ° C.
B: SEBS (manufactured by Asahi Kasei Chemicals Corporation, trade name "S.O.E.S. 1606")
SP value 17.5 (J / cm ³ ) ^1/2 or more, refractive index 1.536, Tg −13 ° C.
C: SEBS (manufactured by Asahi Kasei Chemicals Corporation, trade name "S.O.E.S 1611")
SP value 17.5 (J / cm ³ ) ^1/2 or more, refractive index 1.530, Tg 9 ° C.
D: SEBS (manufactured by Asahi Kasei Chemicals Corporation, trade name "Tuftec H1043")
SP value less than 17.5 (J / cm ³ ) ^1/2 , refractive index 1.549, Tg −55 ° C.
E: SEBS (manufactured by Asahi Kasei Chemicals, trade name "Tough Tech H1051")
SP value less than 17.5 (J / cm ³ ) ^1/2 , refractive index 1.525, Tg -44 ° C

According to Examples 1 to 5, the present invention is a transparent noncombustible sheet excellent in flexibility and capable of maintaining transparency for a long period of time without causing whitening scratches inside the sheet even if folding and folding are repeated. In particular, Examples 1 to 3 use a styrenic thermoplastic elastomer having an SP value of 17.5 (J / cm ³ ) ^1/2 or more and a hydrogenated butadiene portion, and it is possible to use a glass fiber fabric. And the flexibility was also a good result.

Claims (4)

An intermediate layer formed by impregnating a glass fiber fabric with a styrenic thermoplastic elastomer,
A transparent noncombustible sheet characterized in that a vinyl chloride resin film layer is laminated on both sides of the intermediate layer.
The transparent incombustible sheet according to claim 1, wherein a difference in refractive index between the glass fiber cloth and the styrene thermoplastic elastomer is 0.03 or less.
The transparent incombustible sheet according to claim 1 or 2, wherein the total light transmittance of the sheet is 80% or more and the haze is 30% or less.
The styrenic thermoplastic elastomer is a hydrogenated styrenic thermoplastic elastomer, and the SP value of the hydrogenated butadiene portion is 17.5 (J / cm ³ ) ^1/2 or more. The transparent noncombustible sheet according to any one of Items 1 to 3.