Fire resistant sheet and covered article

Abstract

Provided are a fire resistant sheet having an excellent fire retardant property, and an article covered with the fire resistant sheet. The present invention provides a fire resistant sheet and an article covered with the fire resistant sheet, the fire resistant sheet characterized by comprising: a fiber base material layer including a non-melting fiber A having a high-temperature shrinkage rate of 3% or less and a thermal conductivity pursuant to ISO 22007-3 (2008) of 0.060 W / m･K or less, and a thermoplastic fiber B having an LOI value pursuant to JIS K7201-2 (2007) of 25 or greater; and a resin layer including expandable graphite, the resin having a phase transition temperature pursuant to JIS K7121 (2012) which is lower than an expansion starting temperature of the expandable graphite by 20°C or more.

Description

Fireproof sheets and covering articles

[0001] The present invention relates to a fire-resistant sheet and an article coated with the fire-resistant sheet.

[0002] In the fields of interior materials for aircraft, automobiles, and trains, as well as for buildings and furniture, flame retardancy is required for the skin materials and the materials that cover the inside of the skin materials to ensure safety.

[0003] For example, there are FMVSS-302 and JIS D1201 for automobile interior materials, the 45% ethyl alcohol method for railway interior materials, JIS A1321 for wall covering materials, and the Crib-5 flame retardancy standard for some public facilities, and different standards of flame retardancy are required for each field of use.

[0004] Furthermore, in the case of aircraft seat materials, in addition to the flame retardancy of the skin material alone in a 12-second or 60-second vertical burning test, the entire seat, which combines the seat cushion material with the skin material, must also be flame retardant in a gasoline burner test, and even higher flame retardancy is required.

[0005] To achieve high flame retardancy throughout the entire seat, it is important to suppress combustion of the seat cushion. Common methods for suppressing combustion of the seat cushion include inserting a thick felt made of heat-resistant fibers between the upholstery material and the seat cushion, or kneading a flame retardant into the seat cushion to make the seat cushion itself flame retardant.

[0006] For thick felt made of heat-resistant fibers that are inserted between the skin material and the seat cushion, non-melting heat-resistant fibers such as meta-aramid, para-aramid, and flame-resistant yarn are used, but it has been disclosed that the basis weight of the felt can be reduced by combining non-melting fibers that have a small thermal shrinkage rate at high temperatures with thermoplastic fibers that have a high LOI value (Patent Document 1).

[0007] To make the seat cushion itself flame-retardant, a method has been disclosed in which cushion foam is produced by mixing a carbonization accelerator such as a salen-type copper complex, and commonly used flame retardants such as phosphate esters, halogen-containing organic compounds, and inorganic compounds (Patent Document 2).

[0008] Furthermore, methods for imparting excellent flame retardancy include a method of kneading thermally expandable graphite into a thermoplastic resin to form a molded body (Patent Document 3), which is mainly used in the field of building materials, and a fire-resistant sheet comprising a foamed layer that expands when heat is applied and a protective layer that protects the foamed layer (Patent Document 4).

[0009] International Publication No. 2019-188276 JP 2018-172597 A JP 2019-213629 A JP 2018-162628 A

[0010] The felt described in Patent Document 1, which is a composite of non-melting fibers having a small thermal shrinkage rate at high temperatures and thermoplastic fibers having a high LOI value, can be made lighter in mass than aramid-based felt. However, in view of recent trends toward weight reduction and space saving, particularly in the aircraft field, there is still room for further weight reduction, and there is also room for further improvement in terms of wear resistance against repeated putting on and taking off and use.

[0011] The method of adding a specific flame retardant to cushion foam described in Patent Document 2 imparts flame retardancy, but reduces the foaming ability of the cushion foam, making it difficult to adjust the rigidity of the cushion foam, and there is a concern that the cushion foam may be used in seats, resulting in a decrease in comfort.

[0012] The resin molded bodies and fire-resistant sheets described in Patent Documents 3 and 4 are difficult to fit to curved surfaces and are therefore unsuitable as fire-resistant materials for covering the surface of seat foam. Furthermore, particularly in aircraft seats, if a seat is made by covering foam with a sheet material that has no breathability, there is a risk that the seat will not be able to adequately absorb impacts during an emergency landing.

[0013] Therefore, an object of the present invention is to provide a fire-resistant sheet and a coated article that are not only excellent in durability but also have high flame retardancy, an excellent texture, and good surface quality.

[0014] In order to solve the above problems, the present invention employs the following means.

[0015] (1) A fire-resistant sheet comprising: a fiber substrate layer containing non-melting fiber A having a high-temperature shrinkage rate of 3% or less and a thermal conductivity of 0.060 W / m K or less in accordance with ISO 22007-3 (2008); and thermoplastic fiber B having an LOI value of 25 or more in accordance with JIS K 7201-2 (2007); and a resin layer containing expandable graphite, wherein the resin has a phase transition temperature in accordance with JIS K 7121 (2012) that is 20°C or more lower than the expansion onset temperature of the expandable graphite.

[0016] (2) The expandable graphite contains particles that pass through a sieve having a nominal opening of 150 μm as specified in JIS Z8801-1 (2019) and do not pass through a sieve having a nominal opening of 75 μm, in an amount of 50% by mass or more relative to the total mass of the expandable graphite. (1) The fire-resistant sheet described above.

[0017] (3) Air permeability at 125 Pa according to JIS L1096 (2010) A method is 5 to 400 cc / (cm ２ The fire-resistant sheet according to (1) or (2), wherein

[0018] (4) A fire-resistant sheet according to any one of (1) to (3), which has a reinforcing layer between the fiber substrate layer and the resin layer.

[0019] (5) A fire-resistant sheet according to any one of (1) to (4), in which the content of non-melting fiber A in the layers including the fiber base material layer and the reinforcing layer is 15% by mass or more and 85% by mass or less.

[0020] (6) A fire-resistant sheet according to any one of (1) to (5), in which the layer including the fiber base material layer and the reinforcing layer contains 15 to 85 mass% of thermoplastic fiber B.

[0021] (7) The fire-resistant sheet according to any one of (1) to (6), wherein the non-melting fiber A is a fiber selected from the group consisting of flame-resistant fiber, para-aramid fiber, meta-aramid fiber, and mixtures thereof.

[0022] (8) The fire-resistant sheet according to any one of (1) to (7), wherein the thermoplastic fiber B is a fiber made of a resin selected from the group consisting of anisotropic melt polyester, flame-retardant poly(alkylene terephthalate), flame-retardant poly(acrylonitrile butadiene styrene), flame-retardant polysulfone, poly(ether-ether-ketone), poly(ether-ketone-ketone), polyethersulfone, polyarylate, polyarylene sulfide, polyphenylsulfone, polyetherimide, polyamideimide, and mixtures thereof.

[0023] (9) A coated article covered with the fire-resistant sheet according to any one of (1) to (8).

[0024] The fire-resistant sheet of the present invention and the article coated with the fire-resistant sheet have the above-mentioned features, which make them soft to the touch, durable, and highly flame-retardant. Furthermore, since the fire-resistant sheet easily conforms to the shape of the coated article, the processability of the coating process is excellent, resulting in high-quality coated articles. Furthermore, the fire-resistant sheet of the present invention can be used to cover ordinary cushion foam without using cushion foam, whose rigidity is difficult to adjust, to produce a coated article with excellent flame retardancy, thereby providing a soft-feeling coated article.

[0025] 1A and 1B are explanatory diagrams for explaining a method for assembling a coated article for evaluating the flame retardancy of the coated article used in a combustion test of an aircraft seat cushion, and the combustion test.

[0026] The present invention provides a fire-resistant sheet comprising a fiber substrate layer containing non-melting fiber A having a high-temperature shrinkage rate of 3% or less and a thermal conductivity of 0.060 W / m·K or less in accordance with ISO 22007-3 (2008) and thermoplastic fiber B having an LOI value of 25 or more in accordance with JIS K7201-2 (2007), and a resin layer containing expandable graphite, wherein the resin has a phase transition temperature in accordance with JIS K7121 (2012) that is 20°C or more lower than the expansion onset temperature of the expandable graphite.

[0027] <<High-Temperature Shrinkage Rate>> In the present invention, the high-temperature shrinkage rate refers to a value calculated by measuring the original length L0 of fibers used as the raw material for a fire-resistant sheet under standard conditions (20°C, 65% relative humidity) after leaving the fibers for 12 hours, applying a tension of 0.1 cN / dtex to the fibers, and then exposing the fibers to a dry heat atmosphere at 290°C for 30 minutes without applying a load, sufficiently cooling the fibers under standard conditions (20°C, 65% relative humidity), and then measuring the length L1 of the fibers under a tension of 0.1 cN / dtex, using L0 and L1, according to the following formula: High-Temperature Shrinkage Rate = [(L0 - L1) / L0] × 100(%) When a flame approaches and heat is applied, the thermoplastic fibers melt, and the molten thermoplastic fibers spread in the form of a thin film along the surface of the non-melted fibers (aggregates). As the temperature rises further, both fibers eventually carbonize. However, because the high-temperature shrinkage rate of the non-melting fibers is 3% or less, the area near the high-temperature flame-contact area is less likely to shrink, and the fire-resistant sheet is less likely to break due to thermal stress generated between the low-temperature area not in contact with the flame and the high-temperature area, thereby blocking flames for a long period of time. This achieves excellent flame retardancy as a synthetic leather. In this regard, a low high-temperature shrinkage rate is preferable, but even if the sheet does not shrink, significant expansion due to heat can cause the fire-resistant sheet to break due to thermal stress, so a high-temperature shrinkage rate of -5% or more is preferable. In particular, a high-temperature shrinkage rate of 0 to 2% is preferable.

[0028] <<Thermal Conductivity>> Thermal conductivity is a numerical expression of the ease of heat conduction, and low thermal conductivity means that when a material is heated from one side, the temperature rise in the unheated part is small. ２ , the thickness measured by a method conforming to JIS L1913 (2010) is 2 mm (density 100 kg / m ３Materials with a thermal conductivity of 0.060 W / m·K or less, measured using a test specimen of felt (JIS No. 22007-3 (2008)) according to a method compliant with ISO 22007-3, are less likely to conduct heat. When used as a fireproof sheet and heated from one side, they can suppress the temperature rise on the unheated opposite side, reducing the likelihood of ignition of flammable materials placed on the opposite side. Therefore, when articles are covered with the synthetic leather of the present invention, the flame retardancy of the coated article can be maintained. While a lower thermal conductivity is preferable, the lower limit for readily available fiber materials is approximately 0.020 W / m·K.

[0029] <LOI Value> The LOI value is the minimum volume percentage of oxygen required to sustain combustion of a material in a nitrogen-oxygen gas mixture, and it can be said that the higher the LOI value, the more flammable the material. Thermoplastic fibers with an LOI value of 25 or more according to JIS K7201-2 (2007) are flammable, and even if they ignite, the fire will quickly extinguish once the source of fire is removed. They usually form a charred film in the small area where the fire has spread, and this charred film can prevent the fire from spreading. A higher LOI value is preferable, but the upper limit of the LOI value of materials that are actually available is around 65.

[0030] <<Ignition Temperature>> The ignition temperature is the spontaneous ignition temperature measured by a method in accordance with JIS K7193 (2010).

[0031] Phase transition temperature: The phase transition temperature refers to the glass transition temperature and melting point for crystalline materials, and the glass transition temperature for amorphous materials. The melting point is a value measured according to JIS K7121 (2012). Differential scanning calorimetry (DSC) is performed, and the melting peak temperature is measured when heated at 10°C / min under a nitrogen gas flow. The glass transition temperature is measured according to JIS K7121 (2012), and is the temperature at which a line equidistant in the vertical direction from the extended line of the baselines on the low and high sides when heated at 10°C / min under a nitrogen gas flow intersects with the curve of the stepwise change in the glass transition (midpoint glass transition temperature). Measurement is started at a temperature at least 30°C lower than the glass transition temperature and continued up to a temperature at least 30°C higher than the melting point. In the case of a crystalline material, when multiple endothermic peaks are observed, such as a glass transition temperature derived from the amorphous portion and a melting point derived from the crystalline portion, the lower of these is taken as the phase transition temperature.

[0032] The phase transition temperature is preferably measured using the raw resin, but if it is difficult to measure using the raw resin, the value of the second run sampled from the fireproof sheet may be used. When measuring the second run, the temperature is raised to a temperature 30°C or more higher than the melting point in the first run measurement under the above-mentioned conditions, and immediately thereafter, the temperature is rapidly cooled at a rate of 50°C / min or more, and measurement is performed from a temperature 30°C or more lower than the glass transition temperature.

[0033] <<Non-melting Fiber A>> In the present invention, non-melting fiber A refers to a fiber that does not liquefy when exposed to flame and maintains its fibrous shape. Preferably, it does not liquefy or ignite at a temperature of 800°C, and more preferably, it does not liquefy or ignite at temperatures of 1000°C or higher. Examples of non-melting fibers whose high-temperature shrinkage falls within the range specified in the present invention include flame-resistant fibers, para-aramid fibers, meta-aramid fibers, and glass fibers. Of these, flame-resistant fibers, para-aramid fibers, and meta-aramid fibers are preferred. Flame-resistant fibers are fibers that have been flame-resistant treated using fibers selected from acrylonitrile-based, pitch-based, cellulose-based, and phenol-based fibers as raw materials. These fibers may be used alone or in combination of two or more types. Among these, flame-resistant fibers are preferred because they have a low high-temperature shrinkage and exhibit improved heat resistance at high temperatures due to the oxygen-blocking effect of the film formed by the thermoplastic fiber B described below when exposed to flame, which promotes carbonization. Among various flame-resistant fibers, acrylonitrile-based flame-resistant fibers are more preferred because they have a low specific gravity, flexibility, and excellent flame retardancy. These flame-resistant fibers are obtained by heating and oxidizing an acrylic fiber precursor in high-temperature air. Examples of commercially available products include the flame-resistant fiber "ZOLTEK" (registered trademark) OX manufactured by Zoltek, which was used in the Examples and Comparative Examples described below, as well as "Pyromex" (registered trademark) manufactured by Teijin Limited. Furthermore, meta-aramid fibers generally have a high high-temperature shrinkage that does not satisfy the high-temperature shrinkage specified in the present invention. However, meta-aramid fibers that have been subjected to a high-temperature shrinkage suppression treatment to achieve a high-temperature shrinkage within the range of the present invention can be preferably used. The non-melting fibers preferably used in the present invention are used alone or in a method of combining with a different material, and the fiber length is preferably in the range of 30 to 120 mm, more preferably in the range of 38 to 70 mm. If the fiber length is in the range of 38 to 70 mm, it can be made into a nonwoven fabric sheet by a general needle punching method or hydroentanglement method, and it is easy to combine with a different material.The thickness of the non-melting fibers is not particularly limited, but from the viewpoint of passability through the carding process, the single fiber fineness is preferably in the range of 0.1 to 10 dtex, and more preferably 0.3 to 8 dtex.

[0034] Thermoplastic Fiber B: The thermoplastic fiber B used in the present invention has an LOI value within the range specified in the present invention and a melting point lower than the ignition temperature of the non-melting fiber A (or the melting temperature if there is no melting point). Specific examples include fibers composed of a thermoplastic resin selected from the group consisting of anisotropic melting polyester, flame-retardant poly(alkylene terephthalate), flame-retardant poly(acrylonitrile butadiene styrene), flame-retardant polysulfone, poly(ether-ether-ketone), poly(ether-ketone-ketone), polyethersulfone, polyarylate, polyarylene sulfide, polyphenylsulfone, polyetherimide, polyamideimide, and mixtures thereof. These may be used alone or in combination of two or more. Having an LOI value within the range specified in the present invention suppresses combustion in air and facilitates carbonization of the polymer. Furthermore, since the melting point (or melting temperature if there is no melting point) is lower than the ignition temperature of the non-melting fiber A, the molten polymer forms a film on the surface of the non-melting fiber A and between the fibers, which is further carbonized, thereby enhancing the oxygen-blocking effect and suppressing oxidative degradation of the non-melting fiber A. Furthermore, the carbonized film exhibits excellent flame-resistant properties, thereby maintaining the flame retardancy of the entire coated article covered with the fire-resistant sheet of the present invention. The melting point of the thermoplastic fiber B is preferably at least 200°C lower than the ignition temperature of the non-melting fiber A, and more preferably at least 300°C lower. Among these, polyphenylene sulfide fiber (hereinafter also referred to as PPS fiber) is most preferred in terms of its high LOI value, melting point range, and ease of availability. Even polymers with an LOI value outside the range specified in the present invention can be preferably used if they are treated with a flame retardant to achieve an LOI value within the range specified in the present invention. By including sulfur atoms or phosphorus atoms in the polymer structure or the flame retardant, sulfuric acid or phosphoric acid is generated during thermal decomposition of the polymer or flame retardant, which preferably exhibits a mechanism for dehydrating and carbonizing the polymer substrate. PPS containing sulfur atoms in the polymer is most preferred as the thermoplastic fiber B, and when a flame retardant is used, a phosphorus-based or sulfur-based flame retardant is preferred. It is preferred to use a fiber containing 15% by mass or more of sulfur atoms as the thermoplastic fiber B.Specific examples include PPS and polyesters to which a sulfur-based flame retardant has been added. The upper limit is preferably 50% by mass or less from the viewpoint of fiber strength.

[0035] The ratio of sulfur atoms referred to here can be determined by using a thermogravimetric analyzer to heat approximately 10 mg of a sample under air flow conditions from room temperature to 800°C at a rate of 10°C / min to oxidatively decompose the thermoplastic fiber, and quantitatively analyzing the sulfur oxides in the decomposition gas by gas chromatography.

[0036] The thermoplastic fiber B used in the present invention is used as the thermoplastic resin alone or in a composite with a different material, and the fiber length is preferably in the range of 30 to 120 mm, more preferably in the range of 38 to 70 mm. If the fiber length is in the range of 38 to 70 mm, it can be made into a nonwoven fabric using a general needle punching method or hydroentanglement method, and it is easy to composite with a different material. The thickness of the single fiber of the thermoplastic fiber B is also not particularly limited, but from the viewpoint of passability in the carding process, the single fiber fineness is preferably in the range of 0.1 to 10 dtex, more preferably 0.3 to 8 dtex.

[0037] The PPS fiber preferably used in the present invention has a polymer structural unit of -(C ６ H ４ These are synthetic fibers made of polymers having -(C)- as the main structural unit. Typical examples of these PPS polymers include polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, random copolymers thereof, block copolymers thereof, and mixtures thereof. Particularly preferred PPS polymers are those having -(C)- as the main structural unit of the polymer. ６ H ４ Polyphenylene sulfide containing p-phenylene sulfide units represented by (—S)— is desirable, preferably 90 mol % or more. From the viewpoint of mass, polyphenylene sulfide containing p-phenylene sulfide units is desirable, preferably 80 mass % or more, more preferably 90 mass % or more.

[0038] The PPS fiber used in the present invention is preferably produced by melting the polymer having the phenylene sulfide structural unit at or above its melting point and spinning it through a spinneret to form a fiber. The spun fiber is an undrawn PPS fiber as is. Undrawn PPS fiber has a largely amorphous structure and a high breaking elongation. However, such fibers have poor thermal dimensional stability, so drawn yarns are commercially available that are oriented by hot drawing after spinning to improve the fiber strength and thermal dimensional stability. Several PPS fibers are available, including "TORCON" (registered trademark) (manufactured by Toray Industries, Inc.) and "PROCON" (registered trademark) (manufactured by Toyobo Co., Ltd.).

[0039] In the present invention, the undrawn PPS fiber and the drawn PPS fiber can be used in combination within the range of the present invention. Of course, instead of the PPS fiber, a drawn fiber and an undrawn fiber of the fiber that satisfies the range of the present invention can also be used in combination.

[0040] Fibers C other than non-melting fibers A and thermoplastic fibers B Fibers C other than non-melting fibers A and thermoplastic fibers B may be added to the fibrous substrate layer or reinforcing layer (if a reinforcing layer is present) described below to further impart specific performance. For example, vinylon fibers, modified polyester fibers, nylon fibers, etc. may be used to improve the wettability of the fibrous substrate layer. Changing the wettability can improve the processability when forming a resin layer containing expandable graphite on the fibrous substrate layer. The blending ratio of fiber C is not particularly limited as long as it does not impair the effects of the present invention. However, the blending ratio of fiber C other than non-melting fibers A and thermoplastic fibers B relative to the layer consisting of the fibrous substrate layer and the reinforcing layer (if a reinforcing layer is present) is preferably 20% by mass or less, more preferably 15% by mass or less. When fiber C is used, the lower limit may be 0% by mass since it is an optional component.

[0041] Furthermore, the thickness of the single fiber of the fiber C other than the thermoplastic fiber B is not particularly limited, but from the viewpoint of passability through the carding process, the single fiber fineness is preferably in the range of 0.1 to 10 dtex, and more preferably 0.3 to 8 dtex.

[0042] <<Expandable Graphite-Containing Resin Layer>> The expandable graphite-containing resin layer refers to a layer containing expandable graphite, a resin that supports the expandable graphite, and, as an optional component, a flame retardant other than the expandable graphite.

[0043] Expandable graphite is graphite that expands when heated, and is also called expandable graphite. Expandable graphite has substances such as sulfuric acid introduced between the layers of the graphite, and when heated, these substances gasify and expand. It is desirable to use expandable graphite that has been neutralized to prevent it from reacting with phosphorus compounds, etc.

[0044] The expansion ratio of the expandable graphite in the present invention is preferably 2 to 400 times, and more preferably 5 to 350 times. Here, the expansion ratio refers to the rate of change in volume before and after heating a certain volume of expandable graphite for 30 minutes in a heating oven set at a predetermined temperature. When measuring using a fire-resistant sheet in which a resin layer is formed on a fiber substrate layer, the expansion ratio is determined by calculating the area of ​​20 expandable graphite particles in an optical microscope image at about 30 magnification, and determining the rate of change in area before and after heating. Expandable graphite is commercially available from, for example, Ito Graphite Industries Co., Ltd. and Fuji Graphite Industries Co., Ltd.

[0045] The expansion start temperature of the expandable graphite in the present invention is preferably 120 to 300°C, more preferably 150 to 250°C. By setting the expansion start temperature at least 20°C higher than the phase transition temperature of the resin forming the resin layer containing expandable graphite, the resin layer supporting the expandable graphite softens first upon contact with flame, facilitating the expansion of the expandable graphite. Furthermore, since the resin layer containing expandable graphite must be fixed in a heating furnace such as a tenter when formed, the expansion start temperature must be higher than the fixing temperature. Since the resin forming the resin layer is generally available in the form of an aqueous emulsion, setting the expansion start temperature to 100°C or higher can improve the efficiency of the fixing process. When contacted with flame, the expandable graphite expands to form an insulating layer, and then the thermoplastic fiber B is carbonized, thereby forming an insulating layer in stages. Therefore, setting the expansion start temperature to below the melting point of the thermoplastic fiber B can provide a fire-resistant sheet with superior insulating properties. The expansion starting temperature refers to the lowest heating temperature at which expansion can be visually confirmed when a certain volume of expandable graphite is heated for 30 minutes in a thermal oven set at various temperatures. When checking with a fire-resistant sheet having a resin layer formed on a fiber substrate layer, the expandable graphite particles are observed under an optical microscope at about 30x magnification to determine whether or not expansion has occurred.

[0046] The particle size of the expandable graphite in the present invention is preferably such that, when the nominal mesh size of a sieve mesh conforming to JIS Z8801-1 (2019) is used, particles that pass through a sieve with a nominal mesh size of 150 μm but do not pass through a sieve with a nominal mesh size of 75 μm account for 50% by mass or more of the total mass of the expandable graphite. The particle size is determined by separating a sufficient amount of expandable graphite sample using a sieve mesh conforming to JIS Z8801-1 (2019) and each sieve mesh with a nominal mesh size according to the "dry, manual sieving" method described in JIS Z8815 (1994) based on the mass ratio. The specific method for particle diameters of 1 mm or less is as follows: (a) Stack the sieves on top of a receiver, with the larger mesh size at the top. (b) Place the sample to be charged on the top sieve and cover it. (c) Support the stacked sieves with one hand or with a bent arm so that they are tilted at an angle of about 20 degrees, and tap the sieve frame with the other hand at a rate of about 120 times per minute. During this time, place the sieve horizontally at a rate of four times per minute, rotate it 90 degrees, and tap the sieve frame strongly once or twice. (d) If fine powder adheres to the back of the sieve mesh, gently remove it from the back of the sieve with an appropriate brush, and the fine powder will be counted as under-sieved.

[0047] When it is not possible to prepare a sufficient amount of expandable graphite sample and the particle size of the expandable graphite is confirmed in a fireproof sheet having a resin layer formed on a fiber substrate layer, the expandable graphite particles before expansion are observed at least 20 places in an optical microscope image at about 30x magnification, and the length of the minor axis of the expandable graphite particles is read. The number of expandable graphite particles whose minor axis length is in the range of 75 μm (equivalent to 200 mesh) to 150 μm (equivalent to 100 mesh) is determined as a percentage of the total number (20) of expandable graphite particles observed.

[0048] Regarding the particle size of the expandable graphite, the larger the particle size, the higher the expansion coefficient and the better the heat insulating properties, but if the particle size is too large, the supportability of the expandable graphite decreases and the expandable graphite is more likely to fall off from the resin layer due to friction. In order to achieve both heat insulating properties and abrasion resistance by the expandable graphite, it is preferable that the expandable graphite contains particles that pass through a sieve with a nominal mesh size of 150 μm and do not pass through a sieve with a nominal mesh size of 75 μm in an amount of 50 mass% or more relative to the total mass of the expandable graphite, in a sieve mesh conforming to JIS Z8801-1 (2019).

[0049] The resin supporting the expandable graphite is not limited as long as it is a thermoplastic resin having a phase transition temperature at least 20°C lower than the expansion onset temperature of the expandable graphite. Examples of suitable resins include polyolefin resins such as polyethylene (PE) resin, polypropylene (PP) resin, and ethylene vinyl acetate (EVA) resin, polystyrene (PS) resin, acrylonitrile butadiene styrene (ABS) resin, acrylic resin, polyvinyl chloride (PVC) resin, and thermoplastic elastomers (particularly olefin-based thermoplastic elastomers). Among these, those containing halogens, such as polyvinyl chloride resins, can suppress combustion reactions by radical trapping, thereby expecting a synergistic effect with the expandable graphite. A small amount of thermosetting resin, such as epoxy resin or melamine resin, may be added to improve the coating strength of the resin layer and prevent the expandable graphite from falling off. However, due to concerns that this may inhibit the expansion of the expandable graphite, the ratio of the thermosetting resin to the thermoplastic resin is preferably 20% by mass or less.

[0050] Furthermore, other components may be included in the resin layer containing expandable graphite as needed. For example, adding a flame retardant such as red phosphorus, phosphoric acid ester, metal phosphate, or a phosphorus compound such as ammonium polyphosphate can enhance flame retardancy and improve fireproof and insulating properties. The addition of ammonium polyphosphate is particularly preferred. Hydrous inorganic substances such as aluminum hydroxide and magnesium hydroxide may also be added as flame retardants other than those mentioned above. A dehydration reaction occurs upon heating, and the endothermic action of the resulting water can improve fireproof and insulating properties.

[0051] The mass ratio of resin to expandable graphite is preferably in the range of 1:0.5 to 1:2. If the resin ratio is too high, the expandable graphite will be embedded in the resin, reducing the heat insulating effect due to expansion. On the other hand, if the resin ratio is too low, the support force for the expandable graphite will be weak, making the expandable graphite more likely to fall off due to friction, etc.

[0052] The basis weight of the resin layer containing expandable graphite is not particularly limited, but in order to obtain sufficient fire resistance, it is 10 g / m ２ More preferably, 20 g / m ２ More preferably, 30 g / m ２ The upper limit can be set in accordance with the obtained lightweight effect and fire resistance performance. From the viewpoint of the texture of the fire-resistant sheet and the obtained lightweight effect, the upper limit is set to 150 g / m ２ It is preferable that:

[0053] <<Fiber Base Layer>> The fiber base layer in the present invention contains the non-melting fiber A, the thermoplastic fiber B, and, as an optional component, the fiber C. The fiber base layer may be a woven fabric, a knitted fabric, or a nonwoven fabric sheet, but a nonwoven fabric sheet is preferred because it is flexible and can be easily coated onto a cushion foam for an aircraft seat. The fiber base layer has a basis weight of 50 g / m ２ More preferably, 100 g / m ２ More preferably, 150 g / m ２ or more, and 450 g / m ２ Preferably, 400 g / m or less ２ More preferably, 350 g / m or less ２ The following is even more preferable: When the basis weight of the fiber substrate layer is within the above range, a lightweight cushion foam-covered article for aircraft seats having excellent mechanical properties can be obtained.

[0054] The thickness of the nonwoven fabric sheet of the fiber substrate layer is preferably 0.4 mm or more, as measured by a method conforming to JIS L1913 (2010). When the thickness of the nonwoven fabric sheet is above the lower limit, the fiber substrate layer can have excellent mechanical properties and excellent flame retardancy. Furthermore, when a resin layer containing expandable graphite (described later) is formed, the resin layer does not penetrate to the back side of the fiber substrate layer, resulting in an excellent texture of the fire-resistant sheet. There is no particular upper limit for the thickness of the fiber substrate layer, but it is preferably set based on the mass and thickness of the article coated on cushion foam, etc. From the viewpoint of coating on cushion foam, etc., the upper limit is preferably 4 mm or less.

[0055] The structure of the nonwoven fabric sheet is not limited as long as it is within the range specified in the present invention. However, the density of the nonwoven fabric sheet is preferably 50 kg / m ３ greater than 200 kg / m ３ It is preferable that the load is smaller than 55 to 180 kg / m ３ More preferably, 70 to 160 kg / m ３ It is more preferable that the density is too low. If the density is too low, when a resin layer containing expandable graphite is formed on the fiber substrate layer, the resin will penetrate too much into the fiber substrate layer, resulting in a fire-resistant sheet with a hard texture. Conversely, if the density is too high, the fiber substrate layer itself will become too hard, resulting in a fire-resistant sheet with a hard texture. The density is calculated by dividing the mass of a 30 cm square sample by the thickness measured by a method in accordance with JIS L1913 (2010).

[0056] In order to obtain sufficient entanglement between the fibers, the fiber form used in the nonwoven fabric sheet of the fiber substrate layer of the present invention preferably has a crimp count of 7 or more per 2.54 cm, and more preferably 12 or more per 2.54 cm. The crimp count of the present invention is measured in accordance with JIS L1015 (2010). The crimp count is preferably measured in the raw cotton state, but if this is difficult, it may be measured using a sample obtained by disassembling the fiber substrate layer.

[0057] In order to obtain a more uniform nonwoven fabric sheet, it is preferable that the lengths of the short fibers of non-melting fiber A and thermoplastic fiber B, or fiber C when fiber C is used, are the same. However, the lengths do not have to be exactly the same, and a difference of about ±5% from the length of non-melting fiber A is acceptable. From this perspective, the fiber length of both the non-melting fiber and the fiber length of thermoplastic fiber B or fiber C when fiber C is used is preferably within the range of 30 to 120 mm, more preferably within the range of 38 to 70 mm.

[0058] The method for forming the nonwoven fabric sheet of the present invention is not particularly limited, but examples thereof include needle punching and hydroentangling.

[0059] <<Reinforcing Layer>> A reinforcing layer may be included between the fiber substrate layer and the resin layer containing expandable graphite in order to improve the dimensional stability, abrasion resistance, and mechanical strength of the fire-resistant sheet. Furthermore, even if the fiber substrate layer is stretched by processing tension when the resin layer containing expandable graphite is formed on the fiber substrate layer, a reinforcing layer may be added to improve the processability. Examples of the reinforcing layer include a sheet or film made of fiber. In the case of a fiber sheet, the constituent fibers may be short or long fibers, or the sheet may be made by direct spinning.

[0060] In the case of short fibers, the fiber length is preferably in the range of 30 to 120 mm, more preferably in the range of 38 to 51 mm. If the fiber length is in the range of 38 to 51 mm, it can be easily made into a spun yarn by a general spinning process, and the obtained spun yarn can be woven or knitted by a general method to form a woven or knitted fabric for a reinforcing layer.

[0061] In the case of long fibers, raw silk may be used as it is, or it may be subjected to various commonly known thread processing methods and then woven or knitted to form a reinforcing layer.

[0062] In the case of the direct spinning type, the reinforcing layer can be formed into a nonwoven sheet by the spunbonding method or meltblowing method.

[0063] The material constituting the reinforcing layer is preferably a PPS fiber, for example, since excellent fire resistance can be obtained by including the non-melting fiber A or the thermoplastic fiber B.

[0064] As long as the desired fire resistance and reinforcing effect can be obtained, the reinforcing layer and the fiber base layer may contain other fibers C other than the non-melting fibers A and the thermoplastic fibers B. Among the other fibers C, examples of fibers C-1 suitable for use in the reinforcing layer include polyester, polypropylene, cotton, and wool. Among the other fibers C, examples of fibers C-2 suitable for use in the fiber base layer include polyester, nylon, acrylic, and vinylon. In order to minimize the decrease in fire resistance, the proportion of other fibers C in the combined layer of the fiber base layer and the reinforcing layer (if a reinforcing layer is present) is preferably 20% by mass or less.

[0065] The basis weight of the reinforcing layer is not particularly limited, and can be selected according to the desired reinforcing effect. When a reinforcing layer is included, the basis weight of the reinforcing layer is 10 to 300 g / m ２ is preferable, and more preferably 15 to 280 g / m ２ , more preferably 20 to 250 g / m ２ When the basis weight of the reinforcing layer is within the above range, a lightweight cushion foam-covered article for aircraft seats can be obtained that has excellent mechanical properties.

[0066] The reinforcing layer and the fiber base layer may be bonded by any of mechanical methods such as needle punching or hydroentangling, thermal bonding methods such as thermal calendaring, and bonding methods using an adhesive.

[0067] <<Fiber Substrate Layer, or Fiber Sheet Comprising a Fiber Substrate Layer and a Reinforcing Layer>> The fiber substrate layer alone or the fiber substrate layer combined with a reinforcing layer (sometimes collectively referred to as "fiber sheet") may be heat-set using a tenter or may be calendered. Naturally, the fabric may be used as is. The setting temperature is preferably a temperature that effectively suppresses high-temperature shrinkage, preferably 160 to 240°C, more preferably 190 to 230°C. Calendering adjusts the thickness, i.e., density, of the fiber substrate layer. Therefore, calendering may be performed if the density is too low and the resin layer containing expandable graphite penetrates too deeply into the fiber substrate layer when it is formed on the fiber substrate layer, resulting in an excessively hard texture of the fire-resistant sheet. The calendering speed, pressure, and temperature are not limited as long as a nonwoven fabric sheet having physical properties within the ranges specified in the present invention is obtained.

[0068] If the content of non-melting fiber A in the layer including the fiber base layer and the optional reinforcing layer, i.e., in the fiber sheet, is too low, the function as an aggregate will be insufficient, so the mixing ratio of non-melting fiber A is preferably 15% by mass or more, more preferably 20% by mass or more. From the viewpoint of productivity and strength of the fiber base and the reinforcing layer, the upper limit is preferably 85% by mass or less, more preferably 70% by mass or less, even more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

[0069] If the content of thermoplastic fiber B in the fiber sheet is too low, the thermoplastic fiber will not spread sufficiently in a film shape between the non-melting fibers of the aggregate, so the content of thermoplastic fiber B is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and particularly preferably 30% by mass or more. If the content of thermoplastic fiber B is too high, the carbonized portion will tend to become brittle when exposed to flame, and holes will tend to form in the fiber substrate layer, so the upper limit is preferably 85% by mass or less, more preferably 80% by mass or less.

[0070] The basis weight of the fiber sheet is preferably the basis weight of the fiber substrate layer, or, when a reinforcing layer is included, the basis weight of the fiber substrate layer plus the basis weight of the reinforcing layer. In the case of a fiber sheet including a reinforcing layer, if the content of non-melting fiber A and thermoplastic fiber B in the fiber sheet is high, sufficient effect can be achieved even if the basis weight of the fiber sheet is lower than the total basis weight of the fiber substrate layer and the reinforcing layer as described above. For example, when (1) the content of non-melting fiber A in the fiber sheet is within the above-mentioned preferred range, (2) the content of thermoplastic fiber B in the fiber sheet is within the above-mentioned preferred range, and (3) both (1) and (2) are satisfied, the basis weight of the fiber sheet can be set to 450 g / m ２ Below, 400 g / m ２ Below 350 g / m ２ It is preferable to set the fiber density to 50 g / m or less from the viewpoint of reducing the weight of the fiber sheet. ２ Above all, 100 g / m ２ More than 150 g / m ２ In this case, the basis weight of the fiber base layer and the reinforcing layer in the fiber sheet can be appropriately selected depending on the application. For example, when emphasis is placed on the reinforcing effect and shape stability, it is preferable to increase the basis weight of the reinforcing layer, and when emphasis is placed on softness and ability to conform to the shape of the object to be covered, it is preferable to increase the basis weight of the fiber base layer.

[0071] <<Method for manufacturing fire-resistant sheet>> The fire-resistant sheet of the present invention is manufactured by forming a resin layer containing expandable graphite on a fiber sheet that is a normal fiber substrate layer or a fiber substrate layer bonded with a reinforcing layer. When a resin layer is provided on a fiber substrate layer bonded with a reinforcing layer, it is preferable to form the resin layer on the reinforcing layer side, thereby forming a structure having a reinforcing layer between the fiber substrate layer and the resin layer.

[0072] The method for forming the resin layer is not particularly limited. A resin liquid containing expandable graphite emulsified and dispersed in water or a solvent is prepared, and the resin liquid is applied to or immersed in a fiber sheet including a fiber substrate layer and an optional reinforcing layer, followed by drying. Examples of coating methods include gravure coating and knife coating. Immersion methods involve dipping a fiber sheet in the coating liquid and then squeezing out excess coating liquid with a mangle or similar. Depending on the coating amount and coating method, a viscosity modifier may be used in combination. Multiple coatings may also be performed to achieve the desired coating amount. Drying after coating is performed using a commonly used dryer such as a tenter. It is preferable to dry at a temperature below the expansion onset temperature of the expandable graphite, or, if drying is performed at a temperature above the expansion onset temperature, to shorten the drying time.

[0073] When a resin layer containing expandable graphite is applied, the surface to be coated is not particularly limited, but when a reinforcing layer is provided, applying the resin layer to the surface of the reinforcing layer can prevent excessive resin from penetrating into the fiber substrate layer and maintain the texture of the fire-resistant sheet. Furthermore, by unevenly distributing the resin layer containing expandable graphite on one surface of the fire-resistant sheet, the density of the expandable graphite increases, improving the heat insulating effect.

[0074] Because a portion of the fiber base material layer is firmly adhered by the resin layer containing expandable graphite, the durability against abrasion is improved, and when a hook-and-loop fastener such as "Velcro (registered trademark)" tape is attached to an item covered with a fire-resistant sheet such as cushion foam and the item is repeatedly attached and detached, the fire-resistant sheet can be prevented from fraying or breaking at the "Velcro (registered trademark)" tape portion.

[0075] The thickness of the obtained fire-resistant sheet is preferably 0.4 to 4.0 mm, more preferably 0.5 to 3.5 mm, and even more preferably 0.6 to 3.0 mm, from the viewpoints of flame retardancy, abrasion resistance, texture, and space-saving of the covered article such as a sheet. If the thickness is thinner than the above range, the abrasion resistance is poor, and when integrated with an article such as a seat cushion material, the fire resistance of the entire covered article such as a sheet may be insufficient. On the other hand, if the thickness is thicker than the above range, the texture becomes hard.

[0076] The weight of the fire-resistant sheet is 460 g / m2 from the viewpoints of flame retardancy, abrasion resistance, texture, and weight reduction of the covered article such as the sheet. ２ Preferably, the weight is 60 to 400 g / m or less. ２ More preferably, it is 80 to 350 g / m ２ More preferably, it is 100 to 300 g / m ２ It is particularly preferable that the weight per unit area is equal to or greater than the lower limit of the above range. When the weight per unit area is equal to or greater than the lower limit of the above range, the abrasion resistance is excellent, and when integrated with an article such as a seat cushion material, the flame retardancy of the entire covered article such as a seat is excellent. On the other hand, when the weight per unit area is equal to or less than the upper limit of the above range, the benefit of reducing the weight of the entire covered article such as a seat is extremely large.

[0077] Furthermore, in the fire-resistant sheet of the present invention, the mass ratio of the resin layer containing expandable graphite to the mass of the entire fire-resistant sheet is preferably 5 to 75%, more preferably 5 to 60%, even more preferably 8 to 55%, and particularly preferably 10 to 50%. The resin layer containing expandable graphite of the present invention exhibits excellent heat insulation and flame retardancy, contributing to the weight reduction of the fire-resistant sheet. Therefore, by having the mass ratio of the resin layer containing expandable graphite at or above the lower limit, the fire-resistant sheet alone or when used as a covered article such as a sheet has sufficiently excellent flame retardancy. On the other hand, by having the mass ratio of the resin layer containing expandable graphite at or below the upper limit, the relative mass of the fiber substrate layer is sufficiently large, which provides the fire-resistant sheet with sufficiently excellent dimensional stability when exposed to high-temperature flames and excellent flame retardancy when used as a covered article such as a sheet. Since the mass of the fiber substrate layer can be reduced to impart dimensional stability to the fire-resistant sheet when exposed to high-temperature flames, the benefit of weight reduction can be effectively exerted.

[0078] <Air permeability of fire-resistant sheet> The fire-resistant sheet of the present invention has an air permeability of 5 to 400 cc / (cm) at 125 Pa according to JIS L1096 (2010) Method A. ２ s), and 10 to 300 cc / (cm ２ s), and more preferably 20 to 200 cc / (cm ２s), and more preferably 40 to 150 cc / (cm ２ It is particularly preferable that the air permeability is 5 cc / (cm ２ If the air permeability is less than 400 cc / (cm s), when the foam is covered with a sheet material to make a seat, it becomes difficult to absorb shock and the seating comfort becomes poor at the moment of sitting down. ２ If the value is larger than s, there is a concern that the flame may escape through the gaps in the heat-resistant sheet, reducing the flame retardancy of the covering.

[0079] <<Uses of Fire-Resistant Sheet>> The fire-resistant sheet of the present invention thus obtained has excellent flame retardancy and also excellent physical properties such as texture and abrasion resistance. Its flame retardancy is effective not only when used alone, but also when used to cover articles such as cushion foam. Therefore, in addition to direct use as decoration for ceilings and walls, it can also be used as a covering material for covering seat cushioning and the like. Among these, it is particularly suitable for use as a covering material for covering seat cushioning in automobiles, trains, and ships, which require high flame retardancy, and as a covering material for chairs and sofas in high-rise buildings and public facilities.

[0080] Next, the present invention will be specifically described based on examples. However, the present invention is not limited to these examples. Various modifications and alterations are possible within the scope of the present invention. The methods for measuring various properties used in the examples are as follows.

[0081] [Weight per unit area of ​​fiber substrate layer] The mass of a 30 cm square sample was measured, and ２ Mass per unit (g / m ２ ) Note that if the measurement sample is in the form of a fire-resistant sheet and it is difficult to measure the fiber substrate layer alone, a sample of any area may be used, the resin layer and reinforcing layer may be peeled off, and the value calculated by dividing the mass of the fiber substrate portion by the sample area may be used.

[0082] [Weight per unit area of ​​reinforcing layer] The mass of a 30 cm square sample was measured. ２ Mass per unit (g / m ２) Note that if the measurement sample is in the form of a fire-resistant sheet and it is difficult to measure the reinforcing layer alone, a sample of any area may be used, the fiber base layer and resin layer may be peeled off, and the value calculated by dividing the mass of the reinforcing layer by the sample area may be used.

[0083] [Fireproof sheet basis weight] The mass of a 30 cm square sample was measured, and ２ Mass per unit (g / m ２ If the measurement sample is smaller than 30 cm square, the value calculated by dividing the sample mass by the area of ​​the sample may be used.

[0084] [Weight per unit area of ​​resin layer containing expandable graphite] The weight per unit area (g / m) is calculated by subtracting the weight per unit area of ​​the fiber substrate layer and the weight per unit area of ​​the reinforcing layer from the weight per unit area of ​​the fire-resistant sheet. ２ )

[0085] [Thickness of fiber substrate layer and fire-resistant sheet] The thickness was measured in accordance with JIS L1913 (2010). When the measurement sample is in the form of a fire-resistant sheet and it is difficult to measure the fiber substrate layer alone, the cross section of the sample is photographed at a magnification (specifically, about 30 to 200 times) that is about 50 to 90% of the imaging range of the scanning electron microscope (SEM) in the thickness direction of the entire fire-resistant sheet, and the thickness of the fiber substrate layer portion is read on a scale at any five points in the cross-sectional photograph, and the average value thereof may be used as the thickness of the fiber substrate layer.

[0086] [Contents of Non-Melting Fiber A, Thermoplastic Fiber B, and Fiber C in the Fiber Base Layer and Reinforcing Layer] In this example, the contents were calculated based on the amount of raw fiber used. When measuring the contents using a fire-resistant sheet, the evaluation is performed as follows. (1) Identification of the Fiber Types Constituting the Fiber Base Layer and Reinforcing Layer and the Resin Types Constituting the Expanded Graphite-Containing Resin Layer: The fiber types constituting the fiber base layer and reinforcing layer and the resin types constituting the expandable graphite-containing resin layer are identified using a microscopic Fourier transform infrared spectrophotometer (FT-IR). (2) Removal of the Resin Layer from the Fire-Resistant Sheet: After identifying the resin type in (1) above, the resin is removed using an acid, alkali, or an appropriate organic solvent depending on the resin type. The concentration of the acid, alkali, or organic solvent, as well as the treatment temperature and time for removal, can be adjusted as appropriate. (3) Measurement of the content of various fibers: After identifying the fiber types in (1) above, the mass of each fiber type is measured by sorting based on appearance or by separating by a dissolution method using a solvent suitable for each fiber type, and the content ratio is calculated by dividing the mass of each fiber type by the total mass of the fiber base layer and the reinforcing layer.

[0087] [Evaluation of abrasion durability of fire-resistant sheet] According to JIS L1096 (2010) E method (Martindale method), a standard friction cloth and a fire-resistant sheet were rubbed in multiple directions on the surface coated with a resin layer containing expandable graphite, and the number of rubs until the endpoint was measured. The average of three rubs was calculated and expressed in units of 10 rubs.

[0088] [Flame Retardancy Test of Fire-Resistant Sheets for Automotive Interior Materials] The burning length was measured in accordance with horizontal burning test FMVSS No. 302 for automotive interior materials specified in JIS D1201 (1998). A burning length of 4 inches (102 mm) or less was rated as pass, 4 inches (102 mm) or less was rated as B, 3 inches (76 mm) or less was rated as A, and fail was rated as F.

[0089] [Flame Retardancy Test of Fire-Resistant Sheets for Aircraft Interior Materials] A 12-second vertical flame test was conducted according to 14 CFR Part 25 Section 25.853(a) and Appendix F Part 25, Part I, to measure the afterflame time, drip burn time, and burn length. A afterflame time of 15 seconds or less, a drip burn time of 5 seconds or less, and a burn length of 8 inches (203 mm) or less was deemed a pass and given an A rating, while any other results were deemed a fail and given an F rating.

[0090] [Aircraft Seat Cushion Flame Retardancy Test] A combustion test was conducted in accordance with the gasoline burner test specified in 14 CFR Part 25, Section 25.853(c), Appendix F, Part 25, Part II. Figure 1 illustrates the assembly method for a coated article used in an aircraft seat cushion combustion test to evaluate the flame retardancy of the coated article, and the combustion test. Flexible urethane foam commercially available from Fuji Rubber Industries Co., Ltd. was cut into 450 mm x 500 mm for the seat and 450 mm x 630 mm for the back, designated as urethane foam (seat) 1 and urethane foam (back) 2, respectively. A cover material (seat) 4 and a cover material (back) 5 were prepared by sewing polyphenylene sulfide "Velcro" tape 3 to the fire-resistant sheet of the present invention with meta-aramid thread. The urethane foam (seat) 1 and urethane foam (back) 2 are covered with a cover material (seat) 4 and a cover material (back) 5, respectively, and fixed to an L-shaped frame (not shown) to assemble the coated article 7. The sample mass is measured before testing. The set sample is heated from the side with a burner 6 for two minutes. The burner temperature is measured at five locations across the width at the base of the burner nozzle, with the minimum and maximum temperatures being within a range of 1000±20°C. After heating, the burner is removed from the sample and the sample is left for five minutes. The sample mass is then measured after the five-minute period. The sample is deemed to have passed the test if the flames on the sample are completely extinguished, the combustion lengths of the front and rear of the back cushion and the bottom and top of the seat cushion are all 17 inches (432 mm) or less, and the post-test mass loss is 10.0% or less. A mass loss of 6.0% or less is rated A, and a mass loss of more than 6.0% but 10.0% or less is rated B. If the flame that ignited on the sample after leaving it for 5 minutes did not go out, or if the flame went out but the burning length exceeded 17 inches (432 mm), or if the mass loss rate of the sample was greater than 10.0%, the sample was deemed to have failed and was given an F rating.

[0091] [Durability test of "Velcro (registered trademark)" tape on fire-resistant sheet] In Figure 1, when the "Velcro (registered trademark)" tape portion was repeatedly attached and detached 50 times, the fire-resistant sheet that did not fray around the "Velcro (registered trademark)" tape portion was graded A, the fire-resistant sheet that frayed was graded B, and the fire-resistant sheet that broke was graded F.

[0092] [Evaluation of durability of expandable graphite supported on fire-resistant sheet] In accordance with JIS L1096 (2010) Method E (Martindale method), a standard friction cloth and a fire-resistant sheet were rubbed 20 times in multiple directions on the surface coated with a resin layer containing expandable graphite. When all the expandable graphite on the fire-resistant sheet had fallen off after 20 rubs, the sheet was rated C; when some expandable graphite remained on the fire-resistant sheet after 20 rubs but had fallen off after 50 rubs, the sheet was rated B; and when some expandable graphite remained on the fire-resistant sheet after 50 rubs, the sheet was rated A.

[0093] [Sitting Comfort of Aircraft Seat Cushion] Three experienced panelists evaluated and scored the sitting comfort of the seat portion of the coated article 7 assembled according to the procedure described in the section [Flame Retardance Test of Aircraft Seat Cushion] by sensory evaluation. From the perspective of the elasticity and resilience of the seat cushion at the moment of sitting, the seat cushion covered with the fire-resistant sheet was used as the standard, and judged whether the elasticity and resilience of the seat cushion covered with the fire-resistant sheet were equal to or better than the standard, making it feel moderately excellent and comfortable to sit on, or whether the hardness and thickness of the fire-resistant material inhibited the elasticity and resilience of the seat cushion, making it hard and uncomfortable to sit on. 3 points: comfortable, similar to the cushion alone; 2 points: normal; 1 point: uncomfortable to sit on, and the average score of the three panelists was recorded.

[0094] [Fibers or sheets constituting the fiber substrate layer and the reinforcing layer] <Non-melting fiber A-1> 2.2 dtex flame-resistant fiber manufactured by Zoltek (Oxidized Polyacrylic Nitrile Fiber) ("ZOLTEK" (registered trademark) OX) (length 50 mm, high-temperature shrinkage rate 1.6%, thermal conductivity 0.033 W / m K (200 g / m ２ A needle-punched felt having a thickness of 2 mm was prepared and measured. The number of crimps was 12 (pieces / 25 mm) and the crimp rate was 12%.

[0095] <Non-melting fiber A-2> 2.2 dtex meta-aramid fiber ("ARAWIN" (registered trademark)) manufactured by Toray Advanced Materials Korea Inc. (length 51 mm, high temperature shrinkage rate 5.7%, thermal conductivity 0.033 W / m K (200 g / m ２ The measured shrinkage was measured by heat setting at 250°C to a high temperature shrinkage of 2.4%. The number of crimps was 16 (crimps / 25mm) and the crimp percentage was 15%.

[0096] <Non-melting fiber A-3> 1.7 dtex para-aramid fiber ("Kevlar" (registered trademark)) manufactured by DuPont-Toray Co., Ltd. (length 51 mm, high temperature shrinkage rate 1.8%, thermal conductivity 0.047 W / m K (200 g / m ２ (Measurement was performed by preparing a needle-punched felt having a thickness of 2 mm) was used.

[0097] <Non-melting fiber A-4> 2.3 dtex phenolic fiber ("Kynol" (registered trademark)) manufactured by Gun-ei Chemical Industry Co., Ltd. (length 49 mm, high temperature shrinkage rate 2.4%, thermal conductivity 0.042 W / m K (200 g / m ２ (Measurement was performed by preparing a needle-punched felt having a thickness of 2 mm) was used.

[0098] <Thermoplastic fiber B-1> A drawn PPS fiber having a single fiber fineness of 2.2 dtex and a cut length of 51 mm, "TORCON" (registered trademark) product number S371 manufactured by Toray Industries, Inc. (LOI value 34, melting point 284°C, glass transition temperature 90°C, number of crimps 14 (pieces / 25 mm), crimp ratio 18%) was used. The proportion of sulfur atoms in the fiber was 26.2% by mass.

[0099] <Thermoplastic fiber B-2> "Scivelas" (registered trademark) manufactured by Toray Industries, Inc., which is an anisotropic melt-melting polyester fiber having a single fiber fineness of 5.9 dtex and a cut length of 50 mm (LOI value 31, melting point 336°C, number of crimps 4 (pieces / 25 mm), crimp rate 12%), was used.

[0100] <Thermoplastic fiber B-3> A stretched polyethylene terephthalate (PET) fiber (LOI value 20, melting point 263°C, glass transition temperature 68°C, number of crimps 16 (pieces / 25 mm), crimp rate 19%) with a single fiber fineness of 2.2 dtex and a cut length of 51 mm was used, which was imparted with a phosphorus-based flame retardant by dipping. The LOI value of the flame-retardant-treated fiber was 26.

[0101] <Reinforcing Layer 1> (Spinning) Stretched PPS fiber yarns were mixed using a fiber opener, then further mixed using a punching machine, and then passed through a carding machine to form a sliver. The resulting sliver had a mass of 30.23 g / 5.46 m. ​​The sliver was then drawn using a drawing frame with a total draft set to 8 times, resulting in a sliver of 28.03 g / 5.46 m. ​​The sliver was then twisted to 0.55 T / 2.54 cm and drawn 7.4 times using a roving frame to obtain a roving of 323.20 g / 5.46 m. ​​The sliver was then twisted to 16.4 T / 2.54 cm using a spinning frame, drawn 30 times, and twisted to obtain a spun yarn with a cotton count of 20. The spun yarn with a count of 20 was used as the weft of the scrim. The resulting spun yarn was then second-twisted at 64.7T / 2.54cm using a double twister to form a two-ply yarn of 20. The two-ply yarn of 20 was used as the warp yarn of the scrim.

[0102] (Weaving) The obtained spun yarn was woven with a rapier loom in a plain weave of 113 warp threads / 10 cm and 98 weft threads / 10 cm to obtain a 109 g / m ２ got a scrim.

[0103] <Reinforcing layer 2> 100% PET spunbond nonwoven fabric "Acstar" (registered trademark) product number M1025-5T manufactured by Toray Industries, Inc., basis weight 25 g / m ２ A thickness of 0.07 mm was used.

[0104] [Resin layer containing expandable graphite] <Expandable graphite D-1> Expandable graphite EXP-50S160 manufactured by Fuji Graphite Industries Co., Ltd. was used. The expansion onset temperature measured for the expandable graphite particles alone was 160°C, and the expansion ratio was 285 times. The nominal particle size contained 75% or more of particles that did not pass through a sieve with a nominal opening of 300 μm (equivalent to 50 mesh). The proportion of particles that passed through a sieve with a nominal opening of 150 μm but did not pass through a sieve with a nominal opening of 75 μm was 12.5% ​​by mass.

[0105] <Expandable Graphite D-2> EXP-80S expandable graphite manufactured by Fuji Graphite Industries Co., Ltd. was used. The expansion onset temperature measured for the expandable graphite particles alone was 200°C, and the expansion ratio was 180 times. The nominal particle size contained 75% or more of particles that did not pass through a sieve with a nominal mesh size of 180 μm (equivalent to 80 mesh). The proportion of particles that passed through a sieve with a nominal mesh size of 150 μm but did not pass through a sieve with a nominal mesh size of 75 μm was 4.5% by mass.

[0106] <Expandable Graphite D-3> Expandable graphite EXP-50S300 manufactured by Fuji Graphite Industries Co., Ltd. was used. The expansion onset temperature measured for the expandable graphite particles alone was 300°C, and the expansion ratio was 164 times. The nominal particle size contained 75% or more of particles that did not pass through a sieve with a nominal opening of 300 μm (equivalent to 50 mesh). The proportion of particles that passed through a sieve with a nominal opening of 150 μm but did not pass through a sieve with a nominal opening of 75 μm was 3.5% by mass.

[0107] <Expandable Graphite D-4> Expandable graphite EXP-200S manufactured by Fuji Graphite Industries Co., Ltd. was used. The expansion onset temperature measured for the expandable graphite particles alone was 200°C, and the expansion ratio was 35 times. The nominal particle size contained 60% or more of particles that passed through a sieve with a nominal mesh size of 75 μm (equivalent to 200 mesh). The proportion of particles that passed through a sieve with a nominal mesh size of 150 μm but did not pass through a sieve with a nominal mesh size of 75 μm was 27.8% by mass.

[0108] <Expandable Graphite D-5> Expandable graphite 9510045 manufactured by Ito Graphite Industries Co., Ltd. was used. The expansion onset temperature measured for the expandable graphite particles alone was 200°C, and the expansion ratio was 45 times. The nominal particle size was such that the particles passed through a sieve with a nominal mesh size of 150 μm, and the proportion of particles that did not pass through a sieve with a nominal mesh size of 75 μm was 92.1 mass%.

[0109] <Acrylic Resin E-1> Acrylic resin "Boncoat" (registered trademark) S-5 manufactured by DIC Corporation, catalog value of phase transition temperature (Tg) is -10°C.

[0110] <Styrene-based resin E-2> Acrylic resin "Boncoat" (registered trademark) SK-105-E manufactured by DIC Corporation, with a catalog value of phase transition temperature (Tg) of 100°C.

[0111] <Vinyl chloride resin E-3> Vinyl chloride resin "Vinyblan" (registered trademark) 985 manufactured by Nissin Chemical Industry Co., Ltd., with a catalog value of phase transition temperature (Tg) of 80°C.

[0112] <Melamine Resin E-4> Melamine resin "Amidia" (registered trademark) M-3 and melamine resin crosslinking agent Catalyst ACX manufactured by DIC Corporation. No phase transition due to thermosetting resin.

[0113] [Example 1] (Production of fiber substrate layer) Stretched PPS fiber and flame-resistant fiber were mixed in a fiber opener so that the mass ratio of the stretched PPS fiber to the flame-resistant fiber was 60:40, then further mixed in a punching machine, and then passed through a carding machine to produce a web. The obtained web was laminated in a cross-lap machine and then felted in a needle punch machine to produce a web with a basis weight of 150 g / m. ２ A fiber substrate layer having a thickness of 1.42 mm was obtained.

[0114] (Expandable Graphite-Containing Resin Layer) A dispersion of 9.5 parts by mass of expandable graphite D-1, 7.0 parts by mass of acrylic resin E-1, 3.5 parts by mass of a phosphate ester-based flame retardant ("ADEKA STAB" (registered trademark) FP-600 manufactured by ADEKA Corporation), and 80 parts by mass of water was prepared, and xanthan gum was added to the resulting dispersion to adjust the viscosity to 2000 mPa·s, which was then coated with a knife coater. The layer was then dried in a tenter at 110°C. The coating amount of the expandable graphite-containing resin layer was 45 g / m ２ The resin layer sampled from the fire-resistant sheet had a phase transition temperature (Tg) of -7°C.

[0115] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 1, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was rated B. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was within the acceptable range, and the mass loss rate was an excellent 3.9%. The sensory evaluation of the seat cushion's comfort was rated 3.0 points.

[0116] Example 2 (Production of Fiber Substrate Layer) The same fiber substrate layer as that produced in Example 1 was used as the fiber substrate layer.

[0117] (Resin layer containing expandable graphite) A resin solution was prepared, knife-coated, and dried in the same proportions as in Example 1, except that the resin was changed from acrylic resin E-1 to styrene resin E-2. The coating amount was 43 g / m ２ The resulting fire-resistant sheet had a basis weight of 193 g / m ２ The resin layer sampled from the fire-resistant sheet had a phase transition temperature (Tg) of 96°C.

[0118] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 1, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was rated B. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was within the acceptable range, and the mass loss rate was an excellent 4.2%. The sensory evaluation of the seat cushion comfort was rated 3.0 points.

[0119] Example 3 (Production of Fiber Substrate Layer) The same fiber substrate layer as that produced in Example 1 was used as the fiber substrate layer.

[0120] (Resin layer containing expandable graphite) A resin solution was prepared, knife-coated, and dried in the same proportions as in Example 1, except that the resin was changed from acrylic resin E-1 to vinyl chloride resin E-3. The coating amount was 46 g / m ２ The resulting fire-resistant sheet had a basis weight of 196 g / m ２ The resin layer sampled from the fire-resistant sheet had a phase transition temperature (Tg) of 82°C.

[0121] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 1, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was rated B. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was within the acceptable range, and the mass loss rate was an excellent 3.6%. The sensory evaluation of the seat cushion comfort was rated 3.0 points.

[0122] [Example 4] (Production of fiber substrate layer and reinforcing layer) Stretched PPS fiber and flame-resistant fiber were mixed in a fiber opener so that the mass ratio of the stretched PPS fiber to the flame-resistant fiber was 20:80, and then further mixed in a punching machine, and then passed through a carding machine to produce a web. The obtained web was laminated in a cross-lap machine and then felted in a needle punch machine to produce a web with a basis weight of 62 g / m. ２ The obtained felt and the reinforcing layer 1 were further bonded by a needle punch machine to obtain a felt having a basis weight of 171 g / m ２ A fiber sheet having a thickness of 1.78 mm was obtained.

[0123] (Production of fire-resistant sheet) A resin layer was applied in the same manner as in Example 1. The coating amount was 39 g / m ２ The resulting fire-resistant sheet had a basis weight of 210 g / m ２ The resin layer sampled from the fire-resistant sheet had a phase transition temperature (Tg) of -5°C.

[0124] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 1, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was rated B. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was within the acceptable range, and the mass loss rate was an excellent 3.9%. The sensory evaluation of the seat cushion's comfort was rated 2.7 points.

[0125] [Example 5] (Production of fiber substrate layer and reinforcing layer) Stretched PPS fiber and flame-resistant fiber were mixed in a fiber opener so that the mass ratio of the stretched PPS fiber to the flame-resistant fiber was 60:40, then further mixed in a punching machine, and then passed through a carding machine to produce a web. The obtained web was laminated in a cross-lap machine and then felted in a needle punch machine to produce a web with a basis weight of 150 g / m. ２ The obtained felt and the reinforcing layer 2 were further bonded by a needle punch machine to obtain a felt having a basis weight of 175 g / m ２ A fiber sheet having a thickness of 1.42 mm was obtained.

[0126] (Production of fire-resistant sheet) A resin layer was applied in the same manner as in Example 1. The coating amount was 43 g / m ２ The resulting fire-resistant sheet had a basis weight of 218 g / m ２ The resin layer sampled from the fire-resistant sheet had a phase transition temperature (Tg) of -6°C.

[0127] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 2, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was rated B. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was also within the acceptable range, and the mass loss rate was 7.8%, also within the acceptable range. The sensory evaluation of the comfort of the seat cushion was 2.7 points.

[0128] [Example 6] (Production of fiber substrate layer) Stretched PPS fiber and flame-resistant fiber were mixed in a fiber opener so that the mass ratio of the stretched PPS fiber to the flame-resistant fiber was 10:90, and then further mixed in a punching machine, and then passed through a carding machine to produce a web. The obtained web was laminated in a cross-lap machine and then felted in a needle punch machine to produce a web with a basis weight of 156 g / m. ２ A fiber substrate layer having a thickness of 1.65 mm was obtained.

[0129] (Production of fire-resistant sheet) A resin layer was applied in the same manner as in Example 1. The coating amount was 45 g / m ２The resulting fire-resistant sheet had a basis weight of 201 g / m ２ The resin layer sampled from the fire-resistant sheet had a phase transition temperature (Tg) of -9°C.

[0130] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 2, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was rated B. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was also within the acceptable range, and the mass loss rate was 7.9%, also within the acceptable range. The sensory evaluation of the comfort of the seat cushion was rated 3.0 points.

[0131] [Example 7] (Production of fiber substrate layer) Stretched PPS fiber and flame-resistant fiber were mixed in a fiber opener so that the mass ratio of the stretched PPS fiber to the flame-resistant fiber was 90:10, and then further mixed in a punching machine, and then passed through a carding machine to produce a web. The obtained web was laminated in a cross-lap machine and then felted in a needle punch machine to produce a web with a basis weight of 154 g / m. ２ A fiber substrate layer having a thickness of 1.45 mm was obtained.

[0132] (Production of fire-resistant sheet) A resin layer was applied in the same manner as in Example 1. The coating amount was 46 g / m ２ The resulting fire-resistant sheet had a basis weight of 200 g / m ２ The resin layer sampled from the fire-resistant sheet had a phase transition temperature (Tg) of -8°C.

[0133] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 2, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was rated B. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was also within the acceptable range, and the mass loss rate was 8.9%, also within the acceptable range. The sensory evaluation of the comfort of the seat cushion was 2.7 points.

[0134] [Example 8] (Production of fiber substrate layer and reinforcing layer) Stretched PPS fiber and meta-aramid fiber were mixed in a fiber opener so that the mass ratio of stretched PPS fiber to meta-aramid fiber was 60:40, then further mixed in a punching machine, and then passed through a carding machine to produce a web. The obtained web was laminated in a cross-lap machine and then felted in a needle punch machine to produce a web with a basis weight of 152 g / m. ２ A fiber sheet having a thickness of 1.45 mm was obtained.

[0135] (Production of fire-resistant sheet) A resin layer was applied in the same manner as in Example 1. The coating amount was 45 g / m ２ The resulting fire-resistant sheet had a basis weight of 197 g / m ２ The resin layer sampled from the fire-resistant sheet had a phase transition temperature (Tg) of -7°C.

[0136] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 2, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was rated B. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was within the acceptable range, and the mass loss rate was an excellent 4.9%. The sensory evaluation of the comfort of the seat cushion was rated 2.3 points.

[0137] [Example 9] (Production of fiber substrate layer and reinforcing layer) Stretched PPS fiber and para-aramid fiber were mixed in a fiber opener so that the mass ratio of stretched PPS fiber to para-aramid fiber was 60:40, then further mixed in a punching machine, and then passed through a carding machine to produce a web. The obtained web was laminated in a cross-lap machine and then felted in a needle punch machine to produce a web with a basis weight of 150 g / m. ２ A fiber sheet having a thickness of 1.46 mm was obtained.

[0138] (Production of fire-resistant sheet) A resin layer was applied in the same manner as in Example 1. The coating amount was 43 g / m ２ The resulting fire-resistant sheet had a basis weight of 193 g / m２ The resin layer sampled from the fire-resistant sheet had a phase transition temperature (Tg) of -8°C.

[0139] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 3, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was rated B. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was within the acceptable range, and the mass loss rate was an excellent 4.2%. The sensory evaluation of the seat cushion's comfort was rated 2.3 points.

[0140] [Example 10] (Production of fiber substrate layer and reinforcing layer) Stretched PPS fiber and phenolic fiber were mixed in a fiber opener so that the mass ratio of stretched PPS fiber to phenolic fiber was 60:40, then further mixed in a punching machine, and then passed through a carding machine to produce a web. The obtained web was laminated in a cross-lap machine and then felted in a needle punch machine to produce a web with a basis weight of 152 g / m. ２ A fiber sheet having a thickness of 1.44 mm was obtained.

[0141] (Production of fire-resistant sheet) A resin layer was applied in the same manner as in Example 1. The coating amount was 45 g / m ２ The resulting fire-resistant sheet had a basis weight of 197 g / m ２ The resin layer sampled from the fire-resistant sheet had a phase transition temperature (Tg) of -7°C.

[0142] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 3, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was rated B. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was also within the acceptable range, and the mass loss rate was 5.8%, also within the acceptable range. The sensory evaluation of the comfort of the seat cushion was rated 2.7 points.

[0143] [Example 11] (Production of fiber substrate layer and reinforcing layer) Stretched PPS fiber, anisotropic melt polyester, and flame-resistant fiber were mixed in a fiber opener so that the mass ratio of the stretched PPS fiber, anisotropic melt polyester, and flame-resistant fiber was 20:40:40, respectively, and then further mixed in a punching machine and then passed through a carding machine to produce a web. The obtained web was laminated in a cross-lap machine and then felted in a needle punch machine to produce a web with a basis weight of 157 g / m. ２ A fiber sheet having a thickness of 1.57 mm was obtained.

[0144] (Production of fire-resistant sheet) A resin layer was applied in the same manner as in Example 1. The coating amount was 44 g / m ２ The resulting fire-resistant sheet had a basis weight of 201 g / m ２ The resin layer sampled from the fire-resistant sheet had a phase transition temperature (Tg) of -7°C.

[0145] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 3, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was rated B. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was within the acceptable range, and the mass loss rate was an excellent 4.3%. The sensory evaluation of the seat cushion's comfort was rated 2.3 points.

[0146] [Example 12] (Production of fiber substrate layer and reinforcing layer) Flame-retardant PET fiber and flame-resistant fiber were mixed in a fiber opener so that the mass ratio of the flame-retardant PET fiber to the flame-resistant fiber was 60:40, and then further mixed in a punching machine and then passed through a carding machine to produce a web. The obtained web was laminated in a cross-lap machine and then felted in a needle punch machine to produce a web with a basis weight of 152 g / m. ２ A fiber sheet having a thickness of 1.44 mm was obtained.

[0147] (Production of fire-resistant sheet) A resin layer was applied in the same manner as in Example 1. The coating amount was 43 g / m ２ The resulting fire-resistant sheet had a basis weight of 195 g / m ２The resin layer sampled from the fire-resistant sheet had a phase transition temperature (Tg) of -8°C.

[0148] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 3, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was rated B. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was also within the acceptable range, and the mass loss rate was 9.1%, also within the acceptable range. The sensory evaluation of the comfort of the seat cushion was rated 3.0 points.

[0149] Example 13 (Production of fiber substrate layer and reinforcing layer) The same fiber substrate layer as that produced in Example 4 was used as the fiber substrate layer.

[0150] (Production of fire-resistant sheet) A resin solution was prepared, knife-coated, and dried in the same proportions as in Example 1, except that expandable graphite D-1 was changed to D-4. The coating amount was 41 g / m ２ The resulting fire-resistant sheet had a basis weight of 212 g / m ２ , and the thickness was 1.89 mm.

[0151] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 4, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was rated B. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was also within the acceptable range, and the mass loss rate was 8.7%, also within the acceptable range. The sensory evaluation of the comfort of the seat cushion was 2.7 points.

[0152] Example 14 (Production of fiber substrate layer and reinforcing layer) The same fiber substrate layer as that produced in Example 4 was used as the fiber substrate layer.

[0153] (Production of fire-resistant sheet) A resin solution was prepared, knife-coated, and dried in the same proportions as in Example 1, except that expandable graphite D-1 was changed to D-5. The coating amount was 43 g / m ２ The resulting fire-resistant sheet had a basis weight of 214 g / m ２ , and the thickness was 1.90 mm.

[0154] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 4, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was excellent, with a rating of A. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was within the acceptable range, and the mass loss rate was 4.0%, which was excellent. The sensory evaluation of the comfort of the seat cushion was 2.7 points.

[0155] Example 15 (Production of Fiber Substrate Layer) The same fiber substrate layer as that produced in Example 4 was used as the fiber substrate layer.

[0156] (Production of fire-resistant sheet) The knife gap was changed and the resin coating amount was set to 98 g / m ２ The same resin solution as in Example 14 was used for processing, except that the coating amount was increased. The resulting fire-resistant sheet had a basis weight of 269 g / m ２ The thickness was 2.08 mm. By increasing the coating thickness of the resin layer containing expandable graphite, the air permeability of the fireproof sheet was increased to 1.9 cc / (cm ２ ・s) and the air permeability was low.

[0157] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 4, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was excellent, with a rating of A. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was within the acceptable range, and the mass loss rate was excellent at 2.9%. The sensory evaluation of the comfort of the seat cushion was a low rating of 1.3 points.

[0158]

[0159]

[0160]

[0161]

[0162] [Comparative Example 1] (Production of fiber substrate layer) The fibers used were only stretched PPS fibers, and the basis weight was 167 g / m ２ A fiber substrate layer having a thickness of 1.58 mm was obtained.

[0163] (Production of fire-resistant sheet) A resin layer was applied in the same manner as in Example 1. The coating amount was 43 g / m ２ The resulting fire-resistant sheet had a basis weight of 210 g / m ２ The resin layer sampled from the fire-resistant sheet had a phase transition temperature (Tg) of -8°C.

[0164] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 5, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was rated B. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burn length was unacceptable, and the mass loss rate was 27.8%, which was also unacceptable. The sensory evaluation of the seat cushion's comfort was rated 3.0 points.

[0165] Comparative Example 2 (Fiber Base Layer) A 100% PET spunbond nonwoven fabric, "Acstar" (registered trademark), product number G2200-1S, manufactured by Toray Industries, Inc., with a basis weight of 200 g / m ２ A thickness of 0.53 mm was used.

[0166] (Production of fire-resistant sheet) A resin layer was applied in the same manner as in Example 1. The coating amount was 45 g / m ２ The resulting fire-resistant sheet had a basis weight of 245 g / m ２ The resin layer sampled from the fire-resistant sheet had a phase transition temperature (Tg) of -6°C.

[0167] (Evaluation of various physical properties) The mechanical properties and abrasion resistance were as shown in Table 5, and were sufficient. The abrasion resistance of the expandable graphite was rated B. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line. However, the flame retardancy test for aircraft interior materials failed in both char length and afterflame. When the obtained fire-resistant sheet was covered on a urethane cushion and a seat cushion flame retardancy test was conducted, the test piece was completely burned. The sensory evaluation of the seat cushion's comfort was rated 3.0 points.

[0168] Comparative Example 3 (Production of Fiber Substrate Layer) The same fiber substrate layer as that produced in Example 1 was used as the fiber substrate layer.

[0169] (Resin layer containing expandable graphite) A resin solution was prepared, knife-coated, and dried in the same proportions as in Example 1, except that the resin was changed from acrylic resin E-1 to melamine resin E-4. The coating amount was 45 g / m ２ The resulting fire-resistant sheet had a basis weight of 195 g / m ２ The resin layer sampled from the fire-resistant sheet had a thickness of 1.51 mm. No phase transition temperature was confirmed.

[0170] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 5, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was excellent, with a rating of A. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was within the acceptable range, but the mass loss rate was 15.6%, which was unacceptable. The sensory evaluation of the seat cushion's comfort was 2.0 points.

[0171] Comparative Example 4 (Production of Fiber Substrate Layer) The same fiber substrate layer as that produced in Example 1 was used as the fiber substrate layer.

[0172] (Resin layer containing expandable graphite) A resin solution was prepared, knife-coated, and dried in the same proportions as in Example 1, except that the resin was changed from acrylic resin E-1 to melamine resin E-4 and the expandable graphite was changed from D-1 to D-2. The coating amount was 44 g / m２ The resulting fire-resistant sheet had a basis weight of 194 g / m ２ The resin layer sampled from the fire-resistant sheet had a thickness of 1.59 mm. No phase transition temperature was confirmed.

[0173] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 5, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was excellent, with a rating of A. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was within the acceptable range, but the mass loss rate was 15.9%, which was unacceptable. The sensory evaluation of the seat cushion's comfort was 2.0 points.

[0174] Comparative Example 5 (Production of Fiber Substrate Layer) The same fiber substrate layer as that produced in Example 1 was used as the fiber substrate layer.

[0175] (Resin layer containing expandable graphite) A resin solution was prepared, knife-coated, and dried in the same proportions as in Example 1, except that the resin was changed from acrylic resin E-1 to melamine resin E-4 and the expandable graphite was changed from D-1 to D-3. The coating amount was 45 g / m ２ The resulting fire-resistant sheet had a basis weight of 195 g / m ２ The resin layer sampled from the fire-resistant sheet had a thickness of 1.56 mm. No phase transition temperature was confirmed.

[0176] (Evaluation of various physical properties) The mechanical properties and abrasion resistance are as shown in Table 6, and the properties were sufficient for a fire-resistant sheet. The abrasion resistance of the expandable graphite was excellent, with a rating of A. In addition, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm gauge line, and the flame retardancy test for aircraft interior materials showed good results. The obtained fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burning length was within the acceptable range, but the mass loss rate was 20.8%, which was unacceptable. The sensory evaluation of the seat cushion's comfort was 2.0 points.

[0177]

[0178]

[0179] Reference Example 1 (Production of a Fiber Base Material Layer) The mass blend ratio of the stretched PPS fiber and the flame-resistant fiber was the same as in Example 1, and the basis weight was 246 g / m ２ A fiber substrate layer having a thickness of 2.15 mm was obtained.

[0180] (Production of Fire-Resistant Sheet) The above-mentioned fiber substrate layer was used as it was, without forming a resin layer containing expandable graphite.

[0181] (Evaluation of Various Physical Properties) The mechanical properties and abrasion durability are shown in Table 7, and the sheet exhibited sufficient physical properties for a fire-resistant sheet. Furthermore, the flame retardancy test for automobile interior materials showed self-extinguishing within the 38 mm mark, and the flame retardancy test for aircraft interior materials showed favorable results. The resulting fire-resistant sheet was covered on a urethane cushion, and a seat cushion flame retardancy test was conducted. The burn length was within the acceptable range, and the mass loss rate was 9.2%, also within the acceptable range. The seat cushion's sitting comfort was evaluated as 3.0 points. Comparing Example 1 and Reference Example 1, it can be seen that the fire-resistant sheet of the present invention, which includes a fiber substrate layer and a resin layer containing expandable graphite, has improved fire resistance and durability compared to the sheet of Reference Example 1, which does not use a resin layer containing expandable graphite, even when the total basis weight of the fire-resistant sheet is the same but the thickness is reduced.

[0182]

[0183] In Examples 1 to 3, the blend ratio of the fiber base material layer is the same, but the fiber base material layer is about 40 g / m ２ However, compared to Reference Example 1 shown in Table 7, the mass reduction rate of the urethane cushion is clearly smaller, and it is clear that the fire resistance is improved by combining it with the resin layer containing expandable graphite.

[0184] As shown in Examples 1 to 9, the fire-resistant sheet of the present invention has excellent durability and high flame retardancy. Furthermore, even if a normal cushion foam is used instead of a cushion whose rigidity is difficult to adjust due to the use of a flame retardant, a coated article having excellent flame retardancy can be obtained, resulting in a coated article with a soft feel.

[0185] Furthermore, as in Example 14, by adjusting the particle size distribution of the expandable graphite, the wear resistance of the expandable graphite can be further improved.

[0186] The present invention has excellent flame retardancy, exhibits excellent fire spread prevention effects when applied to combustible materials, and also has excellent physical properties such as texture and abrasion resistance. Therefore, the present invention is suitable for use in the interiors of automobiles, trains, ships, etc. (seats, headrests, tonneau covers, sun visors, ceilings, etc.), interior materials for high-rise buildings and public facilities, and covering materials for furniture (chairs, sofas, etc.), and is particularly suitable for use in the interiors of aircraft seats, which require high flame retardancy.

[0187] 1 Urethane foam (seat) 2 Urethane foam (back) 3 Velcro tape 4 Covering material (seat) 5 Covering material (back) 6 Burner 7 Covering item

Claims

1. A fire-resistant sheet comprising: a fiber substrate layer containing non-melting fiber A having a high-temperature shrinkage rate of 3% or less and a thermal conductivity of 0.060 W / m K or less in accordance with ISO 22007-3 (2008); and thermoplastic fiber B having an LOI value of 25 or more in accordance with JIS K7201-2 (2007); and a resin layer containing expandable graphite, wherein the resin has a phase transition temperature in accordance with JIS K7121 (2012) that is 20°C or more lower than the expansion onset temperature of the expandable graphite, and the expansion onset temperature of the expandable graphite is equal to or lower than the melting point of thermoplastic fiber B.

2. The expandable graphite contains particles that pass through a sieve having a nominal opening of 150 μm as specified in JIS Z8801-1 (2019) and do not pass through a sieve having a nominal opening of 75 μm, relative to the total mass of the expandable graphite. The fire-resistant sheet according to claim 1, wherein the fire-resistant sheet contains 50% by mass or more of particles.

3. Air permeability at 125 Pa conforming to JIS L1096 (2010) A method is 5 to 400 cc / (cm ２ 3. The fire-resistant sheet according to claim 1 or 2, wherein

4. The fire-resistant sheet according to claim 1 or 2, further comprising a reinforcing layer between the fiber substrate layer and the resin layer.

5. 3. The fire-resistant sheet according to claim 1, wherein the content of the non-melting fiber A in the layers including the fiber base layer and the reinforcing layer is 15% by mass or more and 85% by mass or less.

6. The fire-resistant sheet according to claim 1 or 2, wherein the layer including the fiber base material layer and the reinforcing layer contains thermoplastic fiber B in an amount of 15% by mass or more and 85% by mass or less.

7. 3. The fire-resistant sheet according to claim 1, wherein the non-melting fiber A is a fiber selected from the group consisting of flame-resistant fiber, para-aramid fiber, meta-aramid fiber, and mixtures thereof.

8. 3. The fire-resistant sheet according to claim 1 or 2, wherein the thermoplastic fiber B is a fiber made of a resin selected from the group consisting of anisotropic melt-melting polyester, flame-retardant poly(alkylene terephthalate), flame-retardant poly(acrylonitrile butadiene styrene), flame-retardant polysulfone, poly(ether-ether-ketone), poly(ether-ketone-ketone), polyethersulfone, polyarylate, polyarylene sulfide, polyphenylsulfone, polyetherimide, polyamideimide, and mixtures thereof.

9. A coated article covered with the fire-resistant sheet according to claim 1 or 2.