Sheet

Abstract

To provide a novel sheet having a high mechanical strength, capable of retaining a shape for a fixed period of time even exposed to flame.SOLUTION: A sheet includes at least a fiber layer A and a fiber layer B, which are laminated. The fiber layer A includes cellulose fiber and the cellulose fiber includes silicon in the fiber. The fiber B incudes a heat-resistant fiber, in which the lowest of melting point, softening point, and decomposition temperature is 400°C or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a sheet.

Background Art

[0002] In recent years, from the viewpoint of environmental protection, the development of electric vehicles, hybrid vehicles, etc. driven by electric motors has been actively promoted. Electric vehicles, hybrid vehicles, etc. are equipped with a battery pack in which a plurality of battery cells are connected in series or parallel to serve as a power source for the drive electric motor. In the battery cells used in such vehicles, lithium-ion secondary batteries capable of high capacity and high output are mainly used. In lithium-ion secondary batteries, there is a phenomenon called thermal runaway, in which when an abnormality occurs in some battery cells, the battery cells overheat and catch fire, and the overheat propagates to adjacent battery cells. When thermal runaway of a battery cell occurs, the combustible electrolyte burns, and components of the battery cell such as electrodes and battery containers melt and catch fire, and there is a risk that a high-temperature blast will violently eject from individual battery cells.

[0003] In a secondary battery housing container (also referred to as a battery pack) equipped with the above-described battery pack, for example, when one battery cell undergoes thermal runaway, there is a high possibility that adjacent battery cells will also undergo thermal runaway, and as a result, a major accident may occur. Therefore, it has been proposed to use a sheet for suppressing thermal runaway. For example, by providing a heat-insulating sheet between adjacent battery cells to suppress thermal runaway, it is possible to suppress the heat generated by the heat generation or ignition of one battery cell from being transmitted to adjacent battery cells, and ultimately suppress continuous thermal runaway to adjacent cells.

[0004] As a sheet for suppressing thermal runaway, there is known a flame-retardant sheet used for a battery pack in which a plurality of battery cells having an electrode surface having electrodes and an outer peripheral surface orthogonal to the electrode surface and arranged such that the outer peripheral surfaces face each other are connected in series or parallel, the flame-retardant sheet having a pair of flame-retardant materials and an elastic member disposed between the pair of flame-retardant materials (see, for example, Patent Document 1).

[0005] In addition, due to the thermal runaway of the assembled battery in the battery pack, the battery pack may be damaged, and if combustion spreads to other adjacent battery packs, there is a risk of causing a vehicle fire accident. In order to prevent the spread of fire between such adjacent battery packs, it is also required to localize the thermal runaway within the battery pack, and measures have been taken to enhance the fire resistance, heat resistance, and robustness of the container of the battery pack.

[0006] To localize the thermal runaway within the battery pack, various fireproof and heat-insulating sheets have been proposed to protect the case of the battery pack from the high-temperature blast ejected by the thermal runaway of the assembled battery. Such fireproof and heat-insulating sheets include boards obtained by binding mica with a silicone resin-based binder, silica papers formed by papermaking using an inorganic binder on silica fibers, and sheet materials in which fumed silica is encapsulated in a coating material. Since these are made of inorganic materials in terms of composition, they are excellent in fire resistance and have high heat insulation due to the air-containing voids. The fireproof and heat-insulating sheet that protects the case of the battery pack from the high-temperature blast is installed between the assembled battery and the case to block the high-temperature blast ejected from the battery cell that has experienced thermal runaway and prevent the blast from directly hitting the case of the battery pack, thereby preventing damage to the battery pack.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] When a sheet for suppressing thermal runaway is provided between adjacent battery cells or a fire-resistant and heat-insulating sheet for preventing damage to the case is provided between the assembled battery and the case, if thermal runaway occurs in a battery cell, it is conceivable that an impact acts on the sheet, such as a pressing force due to the expansion of the battery cell or a wind pressure due to the ignition of the battery cell. Therefore, the sheet is required to have high mechanical strength.

[0009] On the other hand, in a battery cell that has experienced thermal runaway, since the electrolytic solution is a flammable liquid, it is conceivable that the battery cell rapidly rises to a temperature exceeding 200°C by igniting and burning, and then the ignition at 800°C or higher continues for a certain period of time. It is required that the sheet for suppressing thermal runaway and the sheet for preventing damage to the case of the battery pack can maintain their shape for a certain period of time until the combustion of the battery cell ceases and the fire is extinguished even when exposed to flames.

[0010] The above Patent Document 1 discloses that the flame-retardant material constituting the flame-retardant sheet contains a first inorganic fiber and a second inorganic fiber, and it is more preferable to use, as the second inorganic fiber, one having a melting point exceeding 1000°C. However, as the inorganic fiber having a melting point exceeding 1000°C, silica fiber can be considered, but silica fiber is expensive and has the problem of increasing costs.

[0011] In addition, since the fire-resistant and heat-resistant sheet for protecting the case of the battery pack from high-temperature blast is an inorganic material mainly composed of mica or silica as described above, molding according to the shape of the battery pack is complicated, and like silica fiber, it is expensive and has the problem of increasing costs.

[0012] The main object of the present invention is to provide a novel sheet having high mechanical strength and capable of maintaining its shape for a certain period of time even when exposed to flames.

Means for Solving the Problems

[0013] When the present inventors studied to solve the above problems, they found that at least a sheet in which a fiber layer A and a fabric B are laminated, the fiber layer A contains cellulose fibers, the cellulose fibers contain silicon in the fibers, and the fabric B contains heat-resistant fibers in which the lowest of the melting point, softening point, and thermal decomposition temperature is 400°C or higher, can solve the above problems. The present invention is an invention completed by further intensive studies based on such findings.

[0014] That is, the present invention provides an invention in the following aspects. Item 1. A sheet in which at least a fiber layer A and a fabric B are laminated, the fiber layer A contains cellulose fibers, the cellulose fibers contain silicon in the fibers, the fabric B contains heat-resistant fibers in which the lowest of the melting point, softening point, and thermal decomposition temperature is 400°C or higher. Item 2. The sheet according to Item 1, wherein the fiber layer A and the fabric B are laminated in a state where the cellulose fibers and the heat-resistant fibers are intertwined and integrated. Item 3. The sheet according to Item 2, wherein the fiber layer A is included as a nonwoven web. Item 4. The sheet according to any one of Items 1 to 3, wherein the fiber layer A is included as a nonwoven fabric. Item 5. The sheet according to any one of Items 1 to 4, further including an adhesive layer between the fiber layer A and the fabric B. Item 6. The sheet according to any one of Items 1 to 5, wherein a resin coating layer is further laminated on the side of the fabric B opposite to the side on which the fiber layer A is laminated. Item 7. The sheet according to any one of Items 1 to 6, wherein the heat-resistant fiber is a glass fiber.

Advantages of the Invention

[0015] According to the present invention, it is possible to provide a sheet having high mechanical strength and capable of maintaining its shape for a certain period of time even when exposed to a flame.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0017] The sheet of the present invention is at least a sheet in which a fiber layer A and a fabric B are laminated. In the sheet of the present invention, the fiber layer A contains cellulose fibers, and the cellulose fibers contain silicon in the fibers. Further, the fabric B is characterized by containing heat-resistant fibers in which the lowest of the melting point, softening point, and thermal decomposition temperature is 400°C or higher. Since the sheet of the present invention has such characteristics, it has high mechanical strength and can maintain its shape for a certain period of time even when exposed to fire. Hereinafter, the sheet of the present invention will be described in detail.

[0018] <Fiber layer A> In the sheet of the present invention, the fiber layer A contains cellulose fibers. Further, the cellulose fibers contain silicon in the fibers. The fiber layer A serves to block fire and make it difficult to transfer heat to the fabric B, whereby the sheet of the present invention can maintain its shape for a certain period of time even when exposed to fire. Further, since the fiber layer A contains cellulose fibers containing silicon in the fibers, it can also be made excellent in electrical insulation, and can be suitably used, for example, in battery packs such as lithium ion secondary batteries.

[0019] (1) Cellulose fibers containing silicon Cellulose fibers containing silicon (hereinafter sometimes referred to as "silicon-containing cellulose fibers") serve to act as a barrier against flames and make it difficult to transfer heat to the fabric B. In addition, cellulose fibers are superior in flexibility and texture compared to glass fibers, metal fibers, carbon fibers, ceramic fibers, and mineral fibers. For this reason, as described later, when the fiber layer A is included in the sheet as a nonwoven fabric and the cellulose fibers of the fiber layer A and the heat-resistant fibers of the fabric B are intertwined and laminated in an integrated state, the sheet of the present invention is excellent in processability and it becomes difficult for the fiber layer A and the fabric B to peel off. Further, since cellulose fibers are excellent in texture, they are also excellent in processability when forming the fiber layer A into a nonwoven fabric, which will be described later.

[0020] Examples of cellulose fibers include regenerated cellulose fibers such as viscose rayon, cupra, and solvent-spun cellulose fibers, and semi-synthetic cellulose fibers such as acetate. Viscose rayon and cupra, which do not melt by heat, are preferably mentioned, and viscose rayon is more preferably mentioned in terms of being able to contain a large amount of silicon.

[0021] Also, it is preferable that at least a part of the silicon contained in the cellulose fibers is contained as a silicon compound (a compound containing silicon). Examples of the silicon compound include silicate compounds. Further, it is more preferable that the cellulose fibers contain at least one of sodium, aluminum, magnesium, etc. in addition to silicon. In this case, examples of the silicate compound include silicates such as sodium silicate, aluminum silicate, and magnesium silicate.

[0022] When the cellulose fibers contain silicon and at least one of sodium, aluminum, magnesium, etc., for example, after burning the cellulose fibers at 800°C in the atmosphere, it is possible to make them have the property that fibrous glassy substances remain. Thereby, the shape retention of the sheet of the present invention when exposed to flames can be enhanced.

[0023] When the cellulose fiber contains silicon and sodium, it is preferable that at least a part of silicon and sodium exists as sodium silicate in the cellulose fiber. Similarly, when the cellulose fiber contains silicon and aluminum, it is preferable that at least a part of silicon and aluminum exists as aluminum silicate in the cellulose fiber. When the cellulose fiber contains silicon and magnesium, it is preferable that at least a part of silicon and magnesium exists as magnesium silicate in the cellulose fiber.

[0024] As the content of silicon contained in the cellulose fiber, when measured by X-ray fluorescence analysis, 5 to 30% by mass is preferably mentioned. When the cellulose fiber contains silicon and sodium, as the content of sodium, when measured by X-ray fluorescence analysis, 0.1 to 3% by mass is preferably mentioned. When the cellulose fiber contains silicon and aluminum, as the content of aluminum, when measured by X-ray fluorescence analysis, 0.1 to 3% by mass is preferably mentioned. When the cellulose fiber contains silicon and magnesium, as the content of magnesium, when measured by X-ray fluorescence analysis, 0.1 to 3% by mass is preferably mentioned.

[0025] The fineness of the silicon-containing cellulose fiber is not particularly limited, and examples thereof include 1 to 17 dtex, and more preferably 1 to 10 dtex. The cellulose fiber may be either a staple fiber or a long fiber. Among them, when the fiber layer A described below is a non-woven fabric containing silicon-containing cellulose fiber, and the silicon-containing cellulose fiber of the fiber layer A and the heat-resistant fiber of the fabric B are entangled and laminated in an integrated state, from the viewpoint of improving the entanglement property between the fiber layer A and the fabric B, or from the viewpoint of improving the strength of the sheet when the form of the fiber layer A described below is a non-woven fabric, it is preferable that the silicon-containing cellulose fiber is a staple fiber. As the fiber length of the silicon-containing cellulose fiber, for example, 5 to 200 mm can be mentioned, and 10 to 100 mm is preferably mentioned.

[0026] Silicon-containing cellulose fibers can be produced by known methods or commercially available products can also be used. For example, when the cellulose fibers of silicon-containing cellulose fibers are viscose rayon, a silicon-containing compound such as sodium silicate is added to the viscose stock solution, and the viscose solution is extruded from a nozzle and spun in a spinning bath containing sulfuric acid, and refining, etc. are carried out as necessary to obtain viscose rayon fibers containing silicon.

[0027] Moreover, examples of commercially available products of silicon-containing cellulose fibers include FR CORONA (registered trademark) manufactured by Daiwa Borey Rayon Co., Ltd., Visil manufactured by Sateri, etc.

[0028] (2) Other components In the present invention, the fiber layer A can contain components other than silicon-containing cellulose fibers. Examples of other components include binder fibers, fiber lubricants, flame retardants, flame-retardant fibers, etc.

[0029] Examples of binder fibers include heat-fusible fibers.

[0030] As the heat-fusible component contained in the heat-fusible fiber, those having a melting point of 80 to 170°C are preferable, and those having a melting point of 80 to 140°C are more preferable. Specific examples of the heat-fusible component include polyolefin resins such as polyethylene and polypropylene, and polyester resins such as copolyethylene terephthalate copolymerized with copolymerization components such as isophthalic acid.

[0031] In addition, as the heat-fusible fibers that may be contained in the fiber layer A, there are all-fusion types composed of only a single heat-fusible component, or core-sheath type heat-fusible fibers in which a heat-fusible component is disposed in the sheath portion and a synthetic resin component having a melting point preferably 20 °C or higher, more preferably 30 °C or higher than the melting point of the sheath portion is disposed in the core portion. When the core-sheath type heat-fusible short fibers are used, the core component is not particularly limited. For example, a synthetic resin component having a melting point of 150 to 300 °C, more preferably 200 to 300 °C, and having a melting point 20 °C or higher than the melting point of the sheath component can be mentioned. Specific examples of the above synthetic resin component include polyethylene terephthalate. Examples of commercially available binder fibers include MELTY (trade name) manufactured by Unitika Ltd. The heat-fusible fibers contained in the fiber layer A may be only one type or two or more types. Further, the heat-fusible components contained in the heat-fusible fibers may be only one type or two or more types.

[0032] Examples of the flame retardant include inorganic hydroxides, inorganic hydrates, brominated flame retardants, phosphazene flame retardants, phosphate ester flame retardants, antimony flame retardants, intumescent flame retardants, silicone flame retardants, and the like. Examples of the inorganic hydroxide include aluminum hydroxide (Al(OH)3), magnesium hydroxide (Mg(OH)2), calcium hydroxide (Ca(OH)2), zinc hydroxide (Zn(OH)2), iron hydroxide (Fe(OH)2), manganese hydroxide (Mn(OH)2), zirconium hydroxide (Zr(OH)2), gallium hydroxide (Ga(OH)3), and the like. Examples of the inorganic hydrate include calcium sulfate dihydrate, copper(II) sulfate pentahydrate, lithium sulfate monohydrate, magnesium chloride dihydrate, zirconium(IV) sulfate tetrahydrate. The flame retardant contained in the fiber layer A may be only one type or two or more types.

[0033] A flame-retardant fiber refers to a fiber with a limiting oxygen index (LOI) of 26 or more as defined by the JIS L 1091 E-2 method. Examples include meta-aramid fibers, para-aramid fibers, poly(paraphenylene benzoxazole) fibers, polybenzimidazole fibers, polyimide fibers, polyetherimide fibers, polyamideimide fibers, carbon fibers, polyphenylene sulfide fibers, polyvinyl chloride fibers, flame-retardant rayon, modacrylic fibers, flame-retardant acrylic fibers, flame-retardant polyester fibers, flame-retardant vinylon fibers, melamine fibers, and fluorine fibers. The flame-retardant fiber contained in the fiber layer A may be only one type or two or more types.

[0034] In the sheet of the present invention, the mass (g / m 2 ) of the silicon-containing cellulose fiber in the mass (g / m 2 ) of the fiber layer A, for example, may be 70 to 100% by mass, preferably 80 to 100% by mass, and more preferably 95 to 100% by mass.

[0035] In the sheet of the present invention, the form of the fiber layer A is preferably a nonwoven fabric.

[0036] Examples of the nonwoven fabric include a long-fiber nonwoven fabric or a short-fiber nonwoven fabric. Examples of the long-fiber nonwoven fabric include a spunbond nonwoven fabric, a tow-opened nonwoven fabric, and a meltblown nonwoven fabric made of continuous fibers. Examples of the short-fiber nonwoven fabric include a spunlace nonwoven fabric, a needle-punched nonwoven fabric, and a wet-laid nonwoven fabric. Among them, from the viewpoint of being more likely to prevent the dropout of the silicon-containing cellulose fiber, it is preferable to use a spunlace nonwoven fabric. When using a nonwoven fabric, it can be a laminated nonwoven fabric with a fiber layer other than the fiber layer A, and it is preferably a laminated nonwoven fabric in which the fiber layer A and the binder fiber layer described later are laminated, and more preferably a laminated spunlace nonwoven fabric in which the fiber layer A and the binder fiber layer described later are laminated.

[0037] Further, the nonwoven fabric may be a nonwoven fabric web. Examples of the nonwoven fabric web include a dry web produced by a dry lamination method such as a carding method using a carding machine or an air-laying method, and a wet web produced by a wet lamination method. Among them, a dry web is preferably used. The nonwoven fabric web can be a short fiber nonwoven fabric web or a long fiber nonwoven fabric web, and a short fiber card web produced by a carding method is preferably used.

[0038] In the sheet of the present invention, the mass (g / m 2 ) of the fiber layer A is, for example, 50 to 400 g / m 2 , preferably 100 to 300 g / m 2 . Further, the ratio of the mass (g / m 2 ) of the fiber layer A to the mass (g / m 2 ) of the sheet of the present invention is, for example, 50 to 90% by mass, preferably 60 to 80% by mass.

[0039] <Fabric B> The sheet of the present invention includes a fabric B containing a heat-resistant fiber having the lowest melting point, softening point, and thermal decomposition temperature of 400°C or higher. By including the fabric B, the sheet of the present invention can exhibit high mechanical strength. Further, in the sheet of the present invention, the above-described fiber layer A acts as a barrier to flames and makes it difficult to transfer heat to the fabric B, so that high mechanical strength can be maintained for a certain period of time. The lowest of the melting point, softening point, and thermal decomposition temperature is preferably 500°C or higher, more preferably 600°C or higher. Generally, heat-resistant fibers having a melting point have a softening point and a thermal decomposition temperature, while heat-resistant fibers having no melting point have no softening point and only have a thermal decomposition temperature. In the present invention, the heat-resistant fibers contained in the fabric B preferably have a melting point, a softening point, and a thermal decomposition temperature.

[0040] In the present invention, the melting point and softening point of the heat-resistant fiber respectively mean the endothermic peak temperature in differential scanning calorimetry (DSC). Further, in the present invention, the thermal decomposition temperature of the heat-resistant fiber means the temperature at which the weight of the fiber decreases by 5% when thermogravimetric analysis (TGA) is performed in a nitrogen atmosphere. Examples of the heat-resistant fiber having a melting point or softening point of 400°C or higher include inorganic fibers having a melting point or softening point of 400°C or higher (for example, glass fibers, metal fibers, carbon fibers, ceramic fibers, mineral fibers, etc.). Examples of the heat-resistant fiber having a thermal decomposition temperature of 400°C or higher include, in addition to the above heat-resistant fibers having a melting point or softening point of 400°C or higher, organic fibers having a thermal decomposition temperature of 400°C or higher, such as para-aramid fibers, meta-aramid fibers, polybenzoxazole fibers (PBO fibers), polyimide fibers, polybenzimidazole fibers (PBI fibers), and polyarylate fibers.

[0041] The glass material constituting the glass fiber is not particularly limited, and known glass materials can be used. Specific examples of the glass material include non-alkali glass (E glass), acid-resistant alkali-containing glass (C glass), high-strength and high-modulus glass (S glass, T glass, etc.), alkali-resistant glass (AR glass), and the like. Among these glass materials, non-alkali glass (E glass) with high versatility is preferably mentioned.

[0042] The metal fiber is not particularly limited, and examples thereof include boron fiber, titanium fiber, steel fiber, etc. The carbon fiber is not particularly limited, and examples thereof include PAN-based, pitch-based, etc. The ceramic fiber is not particularly limited, and examples thereof include alumina fiber, silica fiber, mullite fiber, zirconia fiber, silicon carbide fiber, etc. The mineral fiber is not particularly limited, and examples thereof include basalt fiber, etc.

[0043] Among heat-resistant fibers, inorganic fibers with the lowest melting point, softening point, and thermal decomposition temperature of 400 °C or higher are more preferable. Further, from the viewpoint of further achieving both heat resistance, high mechanical strength, and electrical insulation among the above inorganic fibers, glass fibers are more preferable.

[0044] In the sheet of the present invention, the heat-resistant fibers contained in the fabric B may be formed of only one type or may contain two or more types.

[0045] In the sheet of the present invention, the heat-resistant fibers are contained in the yarns constituting the fabric B. Examples of the form of the yarn containing the heat-resistant fibers include a monofilament yarn composed of one continuous single fiber, a multifilament yarn composed of a plurality of continuous single fibers, a spun yarn containing short-fiberized heat-resistant fibers, etc. From the viewpoint of being more excellent in mechanical strength, it is preferable to use a multifilament yarn. Further, as the weft yarn constituting the fabric B, it is preferable to use a bulky processed yarn obtained by processing a multifilament yarn into a bulky state with an air jet or the like. In this case, a bulky processed yarn can be obtained by processing a ply yarn in which 2 to 4 multifilament yarns, which are single yarns twisted in the S direction or the Z direction, are twisted together in the direction opposite to that of the multifilament yarn with an air jet or the like.

[0046] The count (tex) of the yarn containing the heat-resistant fibers contained in the fabric B is not particularly limited as long as the fabric B can be formed. The count of the yarn containing the heat-resistant fibers is preferably 3 to 405 tex, more preferably 4 to 270 tex, and even more preferably 30 to 150 tex. The count (tex) of the heat-resistant fibers corresponds to the number of grams per 1000 m. When the yarn containing the heat-resistant fibers is a multifilament yarn composed of a plurality of continuous single fibers, the single fiber diameter of the heat-resistant fibers contained in the yarn is preferably about 3 to 19 μm, more preferably about 4 to 10 μm. When the yarn containing the heat-resistant fibers is a multifilament yarn composed of a plurality of continuous single fibers, the number of single fibers of the heat-resistant fibers contained in the yarn is preferably 50 to 1200, more preferably 100 to 800, and even more preferably 100 to 600.

[0047] When the thread containing the heat-resistant fiber is a multifilament thread composed of a plurality of continuous single fibers, it is preferably twisted from the viewpoint of handleability. The number of twists is preferably 0.5 to 5.0 turns per 25 mm, and more preferably 0.5 to 1.5 turns. The twist direction may be either a known right twist (S twist) or a left twist (Z twist). Also, any of a single-twist thread, various twisted threads, bicore twisted threads, strong-twist threads, wall-twist threads, shuttle-twist threads, etc. may be used. Further, as the thread containing the heat-resistant fiber, it can be a bulky processed thread in which the heat-resistant fiber thread is processed to be bulky by an air jet or the like. In this case, an example is a bulky processed thread obtained by processing a ply yarn in which 2 to 4 heat-resistant fiber threads, which are multifilament threads twisted in the S direction or the Z direction, are twisted together in the direction opposite to that of the glass yarn, to be bulky by an air jet or the like.

[0048] In the present invention, the weave structure of fabric B is not limited, and examples include plain weave, twill weave, imitation gauze weave, twill weave, diagonal weave, rib weave, warp double weave, weft double weave, double weave, etc.

[0049] The intersections (weave points) of the warp and weft of fabric B may be sealed with a resin. Examples of the resin include acrylic resins (including acrylic acid-styrene copolymers), polyvinyl chloride resins, polyolefin resins, polyurethane resins, polyester resins, and one or more resins selected from the group consisting of ethylene-vinyl acetate copolymers. Among them, it is more preferable to contain an ethylene-vinyl acetate copolymer and an acrylic acid-styrene copolymer. When the resin is included, the adhesion amount of the resin in fabric B is, for example, 0.1 to 5.0% by mass, and preferably 1.5 to 4.0% by mass.

[0050] In the present invention, the weave density of fabric B is not particularly limited. For example, 10 to 200 threads / 25 mm can be mentioned, preferably 10 to 100 threads / 25 mm, and more preferably 25 to 60 threads / 25 mm. The mass (g / m 2 ) of fabric B is not particularly limited, but for example, 100 to 1000 g / m2 is mentioned, and 100 to 300 g / m 2 is preferably mentioned.

[0051] Also, in the present invention, the thickness (mm) of the fabric B is not particularly limited, and for example, 0.03 to 0.8 mm is mentioned, and 0.1 to 0.3 mm is preferably mentioned. Further, the ratio of the thickness (mm) of the fabric B to the thickness (mm) of the sheet described later (thickness of the fabric B / thickness of the sheet) is 0.1 to 0.5, and 0.1 to 0.3 is preferably mentioned.

[0052] (Other layers) In the sheet of the present invention, other layers different from the fiber layer A and the fabric B may be further laminated. Examples of the other layer include a binder fiber web layer which is a nonwoven fabric web containing 50% by mass or more of the aforementioned binder fibers, or a binder fiber nonwoven fabric layer which is a nonwoven fabric containing 50% by mass or more of the aforementioned binder fibers. Hereinafter, the "binder fiber web layer" and the "binder fiber nonwoven fabric layer" may be collectively referred to as the "binder fiber layer". By providing a binder fiber layer between the fiber layer A and the fabric B, the adhesiveness between the fiber layer A and the fabric B can be further improved.

[0053] When providing a binder fiber layer on the sheet of the present invention, the fiber layer A and the binder fiber layer can be preliminarily laminated as a laminated nonwoven fabric web or a laminated nonwoven fabric, and then laminated with the fabric B. Also, the fiber layer A which is a nonwoven fabric web and the binder fiber layer which is a nonwoven fabric web can be placed on the fabric B in the order of fiber layer A / binder fiber layer / fabric B, and integrated and laminated by mechanical entanglement such as needle punching.

[0054] When a binder fiber layer is provided on the sheet of the present invention, at least a part of the heat-fusible component of the binder fiber constituting the binder fiber layer melts, and through the melted heat-fusible component, the silicon-containing cellulose fiber in the fiber layer A and the heat-resistant fiber in the fabric B are preferably in a state of being adhered. Examples of the binder fiber contained in the binder fiber layer include the same binder fibers as those exemplified in the fiber layer A. Examples of the ratio of the mass of the binder fiber layer to the mass of the fiber layer A include 20 to 80% by mass, and preferably 35 to 65% by mass.

[0055] In addition, as another layer, an adhesive layer (a layer different from the above-described binder fiber layer) made of a synthetic resin may be further laminated between the fiber layer A and the fabric B on the sheet of the present invention.

[0056] Examples of the resin constituting the adhesive layer include one or more resins selected from the group consisting of acrylic resins, polyvinyl chloride resins, polyolefin resins, polyurethane resins, polyester resins, and ethylene vinyl acetate resins. When the adhesive layer is provided, the mass (g / m 2 ) of the adhesive layer is preferably 3 to 35 g / m 2 , and more preferably 10 to 20 g / m 2 .

[0057] In addition, as another layer, a resin coating layer may be laminated on the side of the fabric B opposite to the side where the fiber layer A is laminated on the sheet of the present invention. By including the resin coating layer in the sheet of the present invention, the sheet of the present invention can exhibit higher mechanical strength. Such an aspect is more likely to exhibit the effect when the sheet of the present invention is laminated in a state where the fiber layer A and the fabric B described later are integrated by needle punching.

[0058] Examples of the resin constituting the resin coating layer include one or more resins selected from the group consisting of acrylic resins, polyvinyl chloride resins, polyolefin resins, polyurethane resins, polyester resins, ethylene vinyl acetate resins, and polyamide resins. Among these, polyurethane resins and polyvinyl chloride resins are preferred in terms of adhesion to the fabric B, heat resistance, flame retardancy, etc.

[0059] Examples of the thickness of the coating resin layer include 8 to 85 μm. Also, examples of the mass of the coating resin layer include 10 to 90 g / m 2 and preferably 10 to 50 g / m 2 is preferably mentioned.

[0060] The resin coating layer can contain a flame retardant. Examples of the flame retardant include inorganic hydroxides, inorganic hydrates, brominated flame retardants, phosphazene flame retardants, phosphate ester flame retardants, antimony flame retardants, intumescent flame retardants, silicone flame retardants, etc. Examples of the inorganic hydroxide include aluminum hydroxide (Al(OH)3), magnesium hydroxide (Mg(OH)2), calcium hydroxide (Ca(OH)2), zinc hydroxide (Zn(OH)2), iron hydroxide (Fe(OH)2), manganese hydroxide (Mn(OH)2), zirconium hydroxide (Zr(OH)2), gallium hydroxide (Ga(OH)3), etc. Examples of the inorganic hydrate include calcium sulfate dihydrate, copper(II) sulfate pentahydrate, lithium sulfate monohydrate, magnesium chloride dihydrate, zirconium(IV) sulfate tetrahydrate. Among them, it is preferably to have inorganic hydroxide or inorganic hydrate particles. When the inorganic hydroxide and inorganic hydrate particles receive heat due to thermal runaway and reach or exceed the thermal decomposition start, they thermally decompose, release the crystal water they possess, and an endothermic reaction occurs, lowering the surrounding temperature. The inclusion of inorganic hydroxide and inorganic hydrate particles imparts both flame retardancy and high thermal conductivity to the resin coating layer. In particular, for example, after aluminum hydroxide releases crystal water, it becomes alumina and has the effect of dissipating heat outward as a high thermal conductivity material and lowering the temperature of the fabric B. The flame retardant contained in the resin coating layer may be only one type or two or more types.

[0061] In the resin coating layer, the mass ratio of the resin to the inorganic hydroxide and the inorganic hydrate particles (resin / inorganic hydroxide and inorganic hydrate particles) is preferably 50 / 50 to 30 / 70.

[0062] As described above, the sheet of the present invention is a laminate of a fiber layer A containing silicon-containing cellulose fibers and a fabric B containing heat-resistant fibers having the lowest melting point, softening point, and thermal decomposition temperature of 400 ° C or higher.

[0063] In the sheet of the present invention, the lamination means of the fiber layer A and the fabric B is not particularly limited. For example, a method of entangling and integrating the silicon-containing cellulose fibers contained in the fiber layer A and the heat-resistant fibers contained in the fabric B by needle punching or the like, a method of joining the fiber layer A and the fabric B with the above-described adhesive layer, and a method of thermally fusing the fiber layer A and the fabric B.

[0064] Here, when the silicon-containing cellulose fibers contained in the fiber layer A and the heat-resistant fibers contained in the fabric B are entangled and integrated by needle punching or the like, the intersections of the warp and weft of the fabric B may be easily displaced by the entanglement process such as needle punching. Therefore, from the viewpoint of further increasing the mechanical strength of the sheet, as described above, it is preferable to provide the above-described resin coating layer on the surface of the fabric B opposite to the side on which the fiber layer A is laminated after the entanglement process such as needle punching.

[0065] As described above, the sheet of the present invention only needs to be laminated with at least a fiber layer A containing silicon-containing cellulose fibers and a fabric B containing heat-resistant fibers having the lowest melting point, softening point, and thermal decomposition temperature of 400 ° C or higher. Specific examples of the laminated structure of the sheet of the present invention are shown in the following (1) - (6).

[0066] (1) A sheet having a laminated structure laminated in the order of the fiber layer A2 / the fabric B3 (see Fig. 1). As the sheet, the fiber layer A2 is a nonwoven web, and the silicon-containing cellulose fiber contained in the fiber layer A2 and the heat-resistant fiber contained in the fabric B3 are preferably in a state of being mechanically entangled and integrated by needle punching or the like.

[0067] (2) A sheet having a laminated structure laminated in the order of the fiber layer A2 / the fabric B3 / the resin coating layer 5 (see Fig. 2). As the sheet, the fiber layer A2 is a nonwoven web, and the silicon-containing cellulose fiber contained in the fiber layer A2 and the heat-resistant fiber contained in the fabric B3 are in a state of being mechanically entangled and integrated by needle punching or the like, and the resin coating layer 5 is provided on the surface of the fabric B3 opposite to the side where the fiber layer A2 is laminated. When the sheet of the present invention is laminated in a state where the fiber layer A2 and the fabric B3 are integrated by needle punching, especially when the sheet of the present invention is laminated in a state where the fiber layer A2 and the fabric B3 are integrated by needle punching and the fabric B is not subjected to a caulking treatment, the effect of excellent mechanical strength is more easily achieved.

[0068] (3) A sheet having a laminated structure laminated in the order of the fiber layer A2 / the adhesive layer 6 / the fabric B3 (see Fig. 3). As the sheet, the fiber layer A2 is present as a nonwoven fabric, more preferably a laminated spunlace nonwoven fabric, and a sheet in which the laminated nonwoven fabric and the fabric B3 are laminated via the adhesive layer 6 is preferably mentioned.

[0069] (4) A sheet having a laminated structure laminated in the order of the fiber layer A2 / the binder fiber layer 4 / the fabric B3 (see FIG. 4). As the sheet, the fiber layer A2 and the binder fiber layer 4 are non-woven webs, and the silicon-containing cellulose fibers contained in the fiber layer A2, the binder fibers contained in the binder fiber layer 4, and the heat-resistant fibers contained in the fabric B3 are mechanically entangled by needle punching or the like and integrated. And at least a part of the heat-fusible component of the binder fiber is melted, and the binder fiber is adhered to the silicon-containing cellulose fiber contained in the fiber layer A2 and the heat-resistant fiber contained in the fabric B. This is preferably the case.

[0070] (5) A sheet having a laminated structure laminated in the order of the fiber layer A2 / the binder fiber layer 4 / the fabric B3 / the resin coating layer 5 (see FIG. 5). As the sheet, the fiber layer A2 and the binder fiber layer 4 are non-woven webs, and the silicon-containing cellulose fibers contained in the fiber layer A2, the binder fibers contained in the binder fiber layer 4, and the heat-resistant fibers contained in the fabric B3 are mechanically entangled by needle punching or the like and integrated. And at least a part of the heat-fusible component of the binder fiber is melted, and the binder fiber is adhered to the silicon-containing cellulose fiber contained in the fiber layer A2 and the heat-resistant fiber contained in the fabric B. A sheet in which the resin coating layer 5 is provided on the surface of the fabric B3 opposite to the side where the fiber layer A2 is laminated is preferably used.

[0071] (6) A sheet having a laminated structure in which a fiber layer A2 / a binder fiber layer 4 / an adhesive layer 6 / a fabric B3 are laminated in this order (see Fig. 6). As the sheet, there is a laminated nonwoven fabric 7 in which the fiber layer A2 and the binder fiber layer 4 are laminated with each other, more preferably a laminated spunlace nonwoven fabric 7. The side surface of the binder fiber layer 4 of the laminated nonwoven fabric 7 and the fabric B3 are laminated via an adhesive layer 6. The silicon-containing cellulose fibers contained in the fiber layer A2 and the binder fibers contained in the binder fiber layer 4 are in an entangled state, and at least a part of the heat-fusible component of the binder fiber is melted, and it is preferably in a state of being adhered to the silicon-containing cellulose fibers via the melted heat-fusible component.

[0072] The mass of the sheet of the present invention is not particularly limited. For example, 200 to 500 g / m 2 is mentioned, and 250 to 350 g / m 2 is preferably mentioned. Further, the thickness of the sheet of the present invention is, for example, 400 to 1200 μm, and 600 to 1000 μm is preferably mentioned. The thickness of the sheet is measured to the digit of 0.001 mm (1 μm) using a micrometer in accordance with Method A described in "7.10.1 Thickness of Cloth" of Japanese Industrial Standard JIS R 3420 2013 "General Test Method for Glass Fibers".

[0073] Since the sheet of the present invention includes the fabric B containing heat-resistant fibers having the lowest melting point, softening point, and thermal decomposition temperature of 400 ° C or higher, it has high mechanical strength. Preferred tensile strengths of the sheet provided by the present invention include 500 N / 25 mm or more, and preferably 700 N / 25 mm or more. The upper limit is not particularly limited, and for example, 5000 N / 25 mm or less can be mentioned. That is, the tensile strength of the sheet can be 500 to 5000 N / 25 mm, and preferably 700 to 5000 N / 25 mm. In the present invention, the tensile strength of the sheet is measured as follows. That is, in accordance with the a) constant speed elongation tensile test method (CRE) described in "7.4 Tensile Strength" of Japanese Industrial Standard JIS R 3420 2013 "General Test Method for Glass Fibers", it is measured and calculated using a type III test piece. However, without removing the yarn, cut both ends of the center of the sample with a cutter knife so as not to be narrower than a width of 25 mm. Measurement is performed in the warp direction and weft direction of the fabric B, and the average value is taken as the tensile strength.

Example

[0074] Hereinafter, the present invention will be described in detail by showing examples and comparative examples. However, the present invention is not limited to the examples.

[0075] (Example 1) (Preparation of fiber layer A) The following were prepared as materials for the fiber layer A. · Silicon-containing cellulose fiber: Flame-retardant rayon fiber (fineness 3.3 dtex, fiber length 51 mm, trade name "FR CORONA", manufactured by Daiwa Bore Rayon Co., Ltd., viscose rayon fiber containing silicon and sodium)

[0076] The prepared silicon-containing cellulose fiber was carded using a carding machine to obtain a non-woven fabric web. The mass of the non-woven fabric web was 75 g / m 2 and set.

[0077] (Preparation of fabric B) The product name is H201 F107, which is an E-glass cloth (manufactured by Unitika Ltd., warp and weft are G75 1 / 0 0.7Z (single fiber diameter 9 μm, number of single fibers 400, count 67.5 tex), warp density is 42 threads / 25 mm, weft density is 31 threads / 25 mm, weave structure is plain weave, thickness is 0.17 mm (measured by Method A described in "7.10.1 Thickness of Cloth" of Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers"), mass is 203 g / m 2 ) was prepared. Next, as a sizing treatment, a resin solution of the following formulation 1 was prepared, the E-glass cloth was immersed in the resin solution, squeezed with a nip roll to obtain the loss on ignition described in Table 1, and dried under the conditions of a temperature of 170 °C and a time of 2 minutes to obtain Fabric B. The thickness of the Fabric B was 0.18 mm and the mass was 208 g / m 2 .

[0078] <Formulation 1> Acrylic acid-styrene copolymer (product name: Cybinol EK-61, manufactured by Cyden Chemical Co., Ltd.): 17.6 parts by mass Ethylene-vinyl acetate copolymer (product name: Polyzol AD-18, manufactured by Resonaak Co., Ltd.): 15.3 parts by mass Silicone resin (antifoaming agent) (product name: KM-73, manufactured by Shin-Etsu Chemical Co., Ltd.): 0.15 parts by mass Mildew preventive (product name: Permachem D-34, manufactured by Permachem Asia Co., Ltd.): 0.05 parts by mass Pure water: 66.9 parts by mass Total: 100 parts by mass

[0079] The obtained nonwoven web was placed on the obtained Fabric B, and needle punching was performed from above the nonwoven web to integrate them, obtaining the sheet of the present invention having a laminated structure of fiber layer A / Fabric B. The sheet was in a state where silicon-containing cellulose fibers and heat-resistant fibers were intertwined and integrated. The physical properties of the sheet are shown in Table 1.

[0080] (Example 2) (Preparation of Fiber Layer A) The following materials were prepared as the materials for Fiber Layer A. · Silicon-containing cellulose fiber: anti-inflammatory rayon fiber (fineness 3.3 dtex, fiber length 51 mm, trade name "FR CORONA", manufactured by Daiwa Bower Rayon Co., Ltd., viscose rayon fiber containing silicon and sodium)

[0081] The prepared silicon-containing cellulose fiber was carded using a carding machine to form a non-woven web. The mass of the non-woven web was 75 g / m 2 as such.

[0082] (Preparation of Fabric B) Product name H201 F107 which is an E-glass cloth (manufactured by Unitika Ltd., warp and weft are G75 1 / 0 0.7Z (single fiber diameter 9 μm, number of single fibers 400, count 67.5 tex), warp density is 42 threads / 25 mm, weft density is 31 threads / 25 mm, weave structure is plain weave, thickness is 0.17 mm (measured by Method A described in "7.10.1 Thickness of Cloth" in Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers"), mass 203 g / m 2 ) was prepared and used as Fabric B.

[0083] The non-woven web used as the fiber layer A was placed on the obtained Fabric B, and needle punching was performed from above the non-woven web used as the fiber layer A to integrate them. Then, a resin solution of Formulation 2 below was prepared, and using a knife coater, the resin solution of Formulation 2 was applied to the surface of Fabric B on the side opposite to the side where the fiber layer A was laminated, heated at 150 °C for 90 seconds to volatilize the solvent to form a resin coating layer, and a sheet of the present invention laminated in the order of fiber layer A / Fabric B / resin coating layer was obtained. The sheet was in a state where the silicon-containing cellulose fiber and the heat-resistant fiber were intertwined and integrated. Also, a resin coating layer was laminated on the surface of Fabric B on the side opposite to the side where the fiber layer A was laminated. The mass ratio of resin / inorganic hydroxide and inorganic hydrate particles in the resin coating layer was 41 / 59. The physical properties of the sheet are shown in Table 1.

[0084] <Formulation 2> Solvent-based urethane resin (solid content 18.4%): 38 parts by mass Aluminum hydroxide: 10 parts by mass Total: 48 parts by mass

[0085] (Example 3) (Preparation of Fiber Layer A) The following materials were prepared as the materials for Fiber Layer A. · Silicon-containing cellulose fiber: Flame-retardant rayon fiber (fineness 3.3 dtex, fiber length 51 mm, trade name "FR CORONA", manufactured by Daiwa Bower Rayon Co., Ltd., viscose rayon fiber containing silicon and sodium)

[0086] The prepared silicon-containing cellulose fiber was carded using a carding machine to form a nonwoven web. The mass of the nonwoven web was 75 g / m 2 as such.

[0087] The nonwoven web was placed on a mesh-like metal support, and a high-pressure liquid stream was injected from above the laminate for entanglement treatment. Subsequently, excess moisture was removed from the entangled nonwoven fabric, and it was dried using a dryer to obtain a laminated spunlace nonwoven fabric as Fiber Layer A.

[0088] (Preparation of Fabric B) Product name H201 F107, which is an E-glass cloth (manufactured by Unitika Ltd., warp and weft are G75 1 / 0 0.7Z (single fiber diameter 9 μm, number of single fibers 400, count 67.5 tex), warp density is 42 threads / 25 mm, weft density is 31 threads / 25 mm, weave structure is plain weave, thickness 0.17 mm (measured by Method A described in "7.10.1 Thickness of Cloth" in Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers"), mass 203 g / m 2 ) was prepared as Fabric B.

[0089] Next, Formulation 3 was prepared as the adhesive for the adhesive layer. From above the prepared Fabric B, the adhesive for the adhesive layer prepared above was applied such that the dried mass was 11 g / m 2Apply it evenly over the entire surface of one side of Fabric B so as to achieve this, heat it at 150 °C for 90 seconds to dry the adhesive, place the laminated spunlace nonwoven fabric prepared on the Fabric B coated with the adhesive, and perform thermocompression bonding with a laminating roll at 175 °C to obtain the sheet of the present invention laminated in the order of (fiber layer A (laminated spunlace nonwoven fabric)) / (adhesive layer) / (Fabric B). The physical properties of the sheet are shown in Table 1. <Formulation 3> Ester-based polyurethane resin (solid content 32.5%): 45 parts by mass Isocyanate-based crosslinking agent: 2.25 parts by mass Total: 47.25 parts by mass

[0090] (Example 4) (Preparation of fiber layer A) The following were prepared as materials for fiber layer A. · Silicon-containing cellulose fiber: Flame-retardant rayon fiber (fineness 3.3 dtex, fiber length 51 mm, product name "FR CORONA", manufactured by Daiwa Bore Rayon Co., Ltd., viscose rayon fiber containing silicon and sodium)

[0091] The prepared silicon-containing cellulose fiber was carded using a carding machine to obtain a nonwoven web. The mass of the nonwoven web was 75 g / m 2 was set.

[0092] (Preparation of Fabric B) Product name H201 F107 which is an E-glass cloth (manufactured by Unitika Ltd., warp and weft are G75 1 / 00.7Z (single fiber diameter 9 μm, number of single fibers 400, count 67.5 tex), warp density is 42 threads / 25 mm, weft density is 31 threads / 25 mm, weave structure is plain weave, thickness is 0.17 mm (measured by method A described in "7.10.1 Thickness of Cross" in Japanese Industrial Standard JIS R 3420 2013 "General Test Method for Glass Fibers"), mass 203 g / m 2 ) was prepared and used as Fabric B.

[0093] Place the nonwoven web that is the aforementioned fiber layer A on top of the aforementioned fabric B, perform needle punching from above the nonwoven web that is the fiber layer A to integrate them, and obtain the sheet of the present invention laminated in the order of fiber layer A / fabric B. The sheet was in a state where the silicon-containing cellulose fiber and the heat-resistant fiber were intertwined and integrated. The physical properties of the sheet are shown in Table 1.

[0094] (Example 5) (Preparation of Fiber Layer A) The following were prepared as materials for fiber layer A. · Silicon-containing cellulose fiber: Flame-retardant rayon fiber (fineness 3.3 dtex, fiber length 51 mm, trade name "FR CORONA", manufactured by Daiwa Bore Rayon Co., Ltd., viscose rayon fiber containing silicon and sodium)

[0095] The prepared silicon-containing cellulose fiber was carded using a carding machine to form a nonwoven web. The mass of the nonwoven web was 50 g / m 2 was used.

[0096] (Preparation of Binder Fiber Layer) As the binder fiber, a core-sheath type heat-fusible short fiber (trade name Meltie 4080, manufactured by Unitika Ltd., 4.4 dtex, fiber length 51 mm) with a PET core and a low-melting-point polyester sheath with a melting point of 110°C was prepared and carded using a carding machine to form a nonwoven web. The mass of the nonwoven web was 25 g / m 2 was used.

[0097] (Preparation of Fabric B) Product name H201 F107 which is an E-glass cloth (manufactured by Unitika Ltd., warp and weft are G75 1 / 0 0.7Z (single fiber diameter 9 μm, number of single fibers 400, count 67.5 tex), warp density is 42 threads / 25 mm, weft density is 31 threads / 25 mm, weave structure is plain weave, thickness 0.17 mm (measured by Method A described in "7.10.1 Thickness of Cloth" in "General Test Method for Glass Fibers" of Japanese Industrial Standard JIS R 3420 2013), mass 203 g / m 2 ) was prepared and used as fabric B.

[0098] One nonwoven web as the obtained fiber layer A, one nonwoven web as the obtained binder fiber layer, and on the obtained fabric B, they are placed in the lamination order of the nonwoven web as the fiber layer A / the nonwoven web as the binder fiber layer / the fabric B. Needle punching is performed from above the nonwoven web as the fiber layer A to integrate them. Then, heat treatment is performed at an ambient temperature of 170 ° C for 5 minutes with a hot air dryer to melt the heat-fusible component of the binder fiber, and the sheet of the present invention laminated in the order of fiber layer A / binder fiber layer / fabric B is obtained. In the sheet, the silicon-containing cellulose fiber contained in the fiber layer A and the binder fiber contained in the binder fiber layer are mechanically entangled and integrated, and the binder fiber contained in the binder fiber layer and the heat-resistant fiber contained in the fabric B are mechanically entangled and integrated. Moreover, at least a part of the heat-fusible component of the binder fiber is melted, and the binder fiber is adhered to the silicon-containing cellulose fiber contained in the fiber layer A and the heat-resistant fiber contained in the fabric B. The physical properties of the sheet are shown in Table 1.

[0099] (Example 6) (Preparation of fiber layer A) The following were prepared as materials for the fiber layer A. · Silicon-containing cellulose fiber: Anti-inflammatory rayon fiber (fineness 3.3 dtex, fiber length 51 mm, trade name "FR CORONA", manufactured by Daiwa Bower Rayon Co., Ltd., viscose rayon fiber containing silicon and sodium)

[0100] The prepared silicon-containing cellulose fiber was carded using a carding machine to obtain a nonwoven web. The mass of the nonwoven web was 50 g / m 2 as.

[0101] (Preparation of binder fiber layer) As the binder fiber, a core-sheath type heat-fusible staple fiber (trade name: Meltie 4080, manufactured by Unitika Ltd., 4.4 dtex, fiber length 51 mm) with a core of PET and a sheath of low-melting polyester with a melting point of 110 °C was prepared. Carding was performed using a carding machine to obtain a nonwoven web. The mass of the nonwoven web was 25 g / m 2 was obtained.

[0102] (Preparation of Fabric B) A product named H201 F107 which is an E-glass cloth (manufactured by Unitika Ltd., warp and weft are G75 1 / 0 0.7Z (single fiber diameter 9 μm, number of single fibers 400, count 67.5 tex), warp density is 42 threads / 25 mm, weft density is 31 threads / 25 mm, weave structure is plain weave, thickness is 0.17 mm (measured by Method A described in "7.10.1 Thickness of Cloth" in JIS R 3420 2013 "General Test Methods for Glass Fibers" of Japan Industrial Standards), mass 203 g / m 2 ) was prepared to obtain Fabric B.

[0103] One nonwoven web as the obtained fiber layer A, one nonwoven web as the obtained binder fiber layer, and the nonwoven web as the fiber layer A / the nonwoven web as the binder fiber layer / the fabric B were placed on the obtained fabric B in this stacking order, and needle punching was performed from above the nonwoven web as the fiber layer A to integrate them. Then, heat treatment was performed at an atmospheric temperature of 170 ° C for 5 minutes using a hot air dryer to melt the heat-fusible component of the binder fiber. Next, a resin solution of the following formulation 2 was prepared, and using a knife coat, the resin solution of formulation 2 was applied to the surface of the fabric B on the side opposite to the side on which the fiber layer A was laminated, and heated at 150 ° C for 90 seconds to volatilize the solvent to form a resin coating layer, and the sheet of the present invention laminated in the order of fiber layer A / binder fiber layer / fabric B / resin coating layer was obtained. In the sheet, the silicon-containing cellulose fiber contained in the fiber layer A and the binder fiber contained in the binder fiber layer were mechanically entangled and integrated, the binder fiber contained in the binder fiber layer and the heat-resistant fiber contained in the fabric B were mechanically entangled and integrated, and at least a part of the heat-fusible component of the binder fiber was melted, and the binder fiber was adhered to the silicon-containing cellulose fiber contained in the fiber layer A and the heat-resistant fiber contained in the fabric B. Further, a resin coating layer was laminated on the surface of the fabric B on the side opposite to the side on which the fiber layer A was laminated. The physical properties of the sheet are shown in Table 1.

[0104] <Formulation 2> Solvent-based urethane resin (solid content 18.4%): 38 parts by mass Aluminum hydroxide: 10 parts by mass Total: 48 parts by mass

[0105] (Example 7) (Preparation of fiber layer A) The following were prepared as materials for the fiber layer A. · Silicon-containing cellulose fiber: Flame-retardant rayon fiber (fineness 3.3 dtex, fiber length 51 mm, trade name "FR CORONA", manufactured by Daiwa Bower Rayon Co., Ltd., viscose rayon fiber containing silicon and sodium)

[0106] The prepared silicon-containing cellulose fiber was carded using a carding machine to obtain a nonwoven web 1. The mass of the nonwoven web was 50 g / m 2 as such.

[0107] (Preparation of Binder Fiber Layer) As the binder fiber, a core-sheath type heat-fusible short fiber (trade name Meltie 4080, manufactured by Unitika Ltd., 4.4 dtex, fiber length 51 mm) with a PET core and a low-melting polyester sheath with a melting point of 110°C was prepared and carded using a carding machine to obtain a nonwoven web 2. The mass of the nonwoven web was 25 g / m 2 as such.

[0108] (Preparation of Fabric B) Product name H201 F107 which is an E-glass cloth (manufactured by Unitika Ltd., warp and weft are G75 1 / 0 0.7Z (single fiber diameter 9 μm, number of single fibers 400, count 67.5 tex), warp density is 42 threads / 25 mm, weft density is 31 threads / 25 mm, weave structure is plain weave, thickness is 0.17 mm (measured by Method A described in "7.10.1 Thickness of Cloth" in Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers"), mass 203 g / m 2 ) was prepared and used as Fabric B.

[0109] One sheet of the nonwoven web 1 and one sheet of the nonwoven web 2 were laminated in the order of nonwoven web 1 / nonwoven web 2, placed on a mesh-like metal support so that the nonwoven web 2 was in the lower position, and entanglement treatment was performed by injecting a high-pressure liquid flow from above the nonwoven web 2. Subsequently, excess moisture was removed from the laminated nonwoven fabric subjected to the entanglement treatment, and drying treatment was performed with a dryer to obtain a laminated spunlace nonwoven fabric in which the fiber layer A and the binder fiber layer were laminated.

[0110] Next, as the adhesive for the adhesive layer, formulation 3 was prepared. From above the prepared fabric B, the adhesive for the adhesive layer prepared above was applied with a dry mass of 11 g / m 2It was uniformly applied to the entire surface of one side of fabric B so as to obtain the following, heated at 150 ° C for 90 seconds to dry the adhesive, and the laminated spunlace nonwoven fabric prepared on fabric B coated with the adhesive was placed so that the binder fibers faced fabric B, and heat - pressed with a laminating roll at 175 ° C to obtain a sheet of the present invention laminated in the order of ((fiber layer A / binder fiber layer (laminated spunlace nonwoven fabric)) / (adhesive layer) / (fabric B)). In the sheet, the silicon - containing cellulose fibers contained in the fiber layer A and the binder fibers contained in the binder fiber layer were mechanically entangled, and at least a part of the heat - fusible component of the binder fibers was melted, and the binder fibers and the silicon - containing cellulose fibers contained in the fiber layer A were adhered. The physical properties of the sheet are shown in Table 1. <Formulation 3> Ester - based polyurethane resin (solid content 32.5%): 45 parts by mass Isocyanate - based cross - linking agent: 2.25 parts by mass Total: 47.25 parts by mass

[0111] (Comparative Example 1) Product name H201 F107 which is an E - glass cloth (manufactured by Unitika Ltd., warp and weft are G75 1 / 0 0.7Z (single - fiber diameter 9μm, number of single - fibers 400, count 67.5 tex), warp density is 42 threads / 25 mm, weft density is 31 threads / 25 mm, weave structure is plain weave, thickness is 0.17 mm (measured by Method A described in “7.10.1 Thickness of Cloth” of Japanese Industrial Standard JIS R 3420 2013 “General Test Method for Glass Fibers”), mass 203 g / m 2 ) was prepared and used as the sheet of Comparative Example 1. The physical properties of the sheet are shown in Table 1.

[0112] (Comparative Example 2) The product name H201 F107, which is an E-glass cloth (manufactured by Unitika Ltd., warp and weft are G75 1 / 0 0.7Z (single fiber diameter 9 μm, number of single fibers 400, count 67.5 tex), warp density is 42 threads / 25 mm, weft density is 31 threads / 25 mm, weave structure is plain weave, thickness 0.17 mm (measured by Method A described in "7.10.1 Thickness of Cloth" in Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers"), mass 203 g / m 2 ) was prepared. Next, as a sizing treatment, a resin solution of the following Formulation 1 was prepared, the E-glass cloth was immersed in the resin solution, squeezed with nip rolls to obtain the loss on ignition described in Table 1, and dried under the conditions of a temperature of 170 °C and a time of 2 minutes to obtain the sheet of Comparative Example 2. The physical properties of the sheet are shown in Table 1.

[0113] <Formulation 1> Acrylic acid-styrene copolymer (product name Cybinol EK-61 manufactured by Siden Chemical Co., Ltd.): 17.6 parts by mass Ethylene-vinyl acetate copolymer (product name Polyzol AD-18 manufactured by Resonaak Co., Ltd.): 15.3 parts by mass Silicone resin (antifoaming agent) (Shin-Etsu Chemical Co., Ltd. product KM-73): 0.15 parts by mass Mildew preventive (Permachem D-34 manufactured by Permachem Asia Co., Ltd.): 0.05 parts by mass Pure water: 66.9 parts by mass Total: 100 parts by mass

[0114] (Comparative Example 3) (Preparation of Fiber Layer A) The following were prepared as materials for Fiber Layer A. · Silicon-containing cellulose fiber: Flame-retardant rayon fiber (fineness 3.3 dtex, fiber length 51 mm, product name "FR CORONA", manufactured by Daiwa Bore Rayon Co., Ltd., viscose rayon fiber containing silicon and sodium)

[0115] The prepared silicon-containing cellulose fiber was carded using a carding machine to obtain a non-woven fabric web. The mass of the non-woven fabric web was 75 g / m 2 was used.

[0116] The nonwoven web was placed on a mesh-shaped metal support, and a high-pressure liquid flow was injected from above the laminate for entanglement treatment. Subsequently, excess moisture was removed from the entangled laminate nonwoven fabric, and it was dried using a dryer to obtain a laminated spunlace nonwoven fabric as Fiber Layer A, which was used as the sheet in Comparative Example 3. The physical properties of the sheet are shown in Table 1.

[0117] (Comparative Example 4) (Preparation of Fiber Layer A) The following materials were prepared as the materials for Fiber Layer A. · Silicon-containing cellulose fiber: Flame-retardant rayon fiber (fineness 3.3 dtex, fiber length 51 mm, trade name "FR CORONA", manufactured by Daiwa Bore Rayon Co., Ltd., viscose rayon fiber containing silicon and sodium)

[0118] The prepared silicon-containing cellulose fiber was carded using a carding machine to form a nonwoven web. The mass of the nonwoven web was 25 g / m 2 as such.

[0119] Twelve of the above nonwoven webs were stacked, and needle punching was performed from above the nonwoven webs to integrate the twelve nonwoven webs, which was used as the sheet in Comparative Example 4. The physical properties of the sheet are shown in Table 1.

[0120] (Comparative Example 5) (Preparation of Glass Wool Sheet) Melted glass was put into a fiberizing device and fiberized by centrifugal force. A binder was sprayed onto the fiberized short glass fibers (adjusted to 10 wt% of the binder component), and a glass wool sheet made of short glass fibers obtained by carding using a carding machine (thickness 1 mm, mass 90 g / m 2 ) was prepared.

[0121] (Preparation of Fabric B) The product name is H201 F107, which is an E-glass cloth (manufactured by Unitika Ltd., warp and weft are G75 1 / 0 0.7Z (single fiber diameter 9 μm, number of single fibers 400, count 67.5 tex), warp density is 42 threads / 25 mm, weft density is 31 threads / 25 mm, weave structure is plain weave, thickness is 0.17 mm (measured by Method A described in "7.10.1 Thickness of Cloth" of Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers"), mass is 203 g / m 2 ) was prepared and used as fabric B.

[0122] Next, as the adhesive for the adhesive layer, formulation 3 was prepared. The adhesive for the adhesive layer prepared above was uniformly applied to the entire one surface of the prepared fabric B so that the dry mass would be 11 g / m 2 , and then heated at 150 °C for 90 seconds to dry the adhesive. A glass wool sheet prepared was placed on the fabric B coated with the adhesive, and heat-pressed with a laminating roll at 175 °C to obtain a sheet of Comparative Example 5 laminated in the order of (glass wool sheet) / (adhesive layer) / (fabric B). The physical properties of the sheet are shown in Table 1. <Formulation 3> Ester-based polyurethane resin (solid content 32.5%): 45 parts by mass Isocyanate-based crosslinking agent: 2.25 parts by mass Total: 47.25 parts by mass

[0123] (Measurement method of physical properties) 1. Count (tex) of warp and weft of fabric B Measured and calculated according to the method described in "7.1 Count" of Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers".

[0124] 2. Single fiber diameter (μm) of glass fibers constituting warp and weft of fabric B For each of the warp and weft, 20 threads were randomly selected, and the cross-section of the entire single fiber diameter (the largest part) of the 20 threads was measured to calculate the average value, which was taken as the single fiber diameter.

[0125] 3. Density of warp and weft of fabric B (threads / 25 mm) In accordance with the method described in "7.9 Density (Weave Density)" of Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers", the weave densities of the warp and weft yarns were measured and calculated.

[0126] 4. Thickness of the sheet (mm) In accordance with Method A described in "7.10.1 Thickness of Cloth" of Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers", measurement was carried out to the digit of 0.001 mm (1 μm) using a micrometer.

[0127] 5. Mass of the sheet (g / m 2 ) In accordance with the method described in "7.2 Mass of Cloth and Mat (Mass)" of Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers", measurement and calculation were carried out.

[0128] 6. Tensile strength of the sheet (mechanical strength, N / 25 mm) In accordance with a) the constant speed elongation tensile test method (CRE) described in "7.4 Tensile Strength" of Japanese Industrial Standard JIS R 3420 2013 "General Test Methods for Glass Fibers", measurement and calculation were carried out using Type III test pieces. However, without removing the yarns, both ends of the central part of the sample were cut with a cutter knife so as not to be narrower than a width of 25 mm. Measurement was carried out in the warp direction and weft direction of Fabric B, and the average value was taken as the tensile strength.

[0129] 7. Evaluation of the performance (flame resistance) of being able to maintain the shape for a certain period of time even when exposed to fire The sheet was cut into a 20 mm × 20 mm square to serve as an evaluation sample. At the central part of the said evaluation sample, a turbo lighter (product name: Cratena Neo F DJ-03M-F, manufactured by Litec Co., Ltd.) was used to flame the sample for 1 minute with the distance from the tip of the turbo lighter to the evaluation sample being 25 mm, and the state of the evaluation sample was observed. Evaluation was carried out according to the following evaluation criteria. Regarding flame application, for Examples 1 to 7, it was carried out on the surface of the fiber layer A side; for Comparative Examples 1 to 4, since they are single layers, the surface is not specified; for Comparative Example 5, it was carried out from the surface of the glass wool sheet. A+: Even when directly exposed to fire for 1 minute, no holes are formed in the evaluation sample. A: After being directly exposed to fire for less than 1 minute, holes are formed in the sample. B: After being directly exposed to fire for less than 30 seconds, holes are formed in the sample. C: After being directly exposed to fire for less than 10 seconds, holes are formed in the sample.

[0130] 8. Fraying property The sheet was cut with scissors, and the occurrence of thread fraying on the cut surface was evaluated according to the following evaluation criteria. A+: There is almost no fraying from the cut surface. A: Slight fraying can be seen from the cut surface. B: Fraying occurs from the cut surface. C: Fraying occurs before cutting.

[0131] The physical properties, etc. of the sheets of Examples 1 to 7 and Comparative Examples 1 to 5 are shown in Table 1.

[0132]

Table 1

Claims

1. A sheet in which at least a fiber layer A and a fabric B are laminated, wherein the fiber layer A contains cellulose fibers, the cellulose fibers contain silicon in the fibers, and the fabric B contains heat-resistant fibers having the lowest melting point, softening point, and thermal decomposition temperature of 400°C or higher.

2. The sheet according to claim 1, wherein the fiber layer A and the fabric B are laminated in a state where the cellulose fibers and the heat-resistant fibers are intertwined and integrated.

3. The sheet according to claim 2, wherein the fiber layer A is included as a nonwoven web.

4. The sheet according to claim 1, wherein the fiber layer A is included as a nonwoven fabric.

5. The sheet according to claim 1, further including an adhesive layer between the fiber layer A and the fabric B.

6. The sheet according to claim 1, further including a resin coating layer laminated on the side of the fabric B opposite to the side where the fiber layer A is laminated.

7. The sheet according to any one of claims 1 to 6, wherein the heat-resistant fibers are glass fibers.

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