Fire-resistant resin composition and thermally expandable sheet

Abstract

To provide a fire-resistant resin composition that has excellent moldability and has excellent water resistance, and a thermally expandable sheet composed of the fire-resistant resin composition.SOLUTION: A fire-resistant resin composition has a resin, thermally expandable graphite, a plasticizer, and at least one flame retardant (A) selected from a red phosphorus flame retardant and a phosphazene flame retardant.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a fire-resistant resin composition and a thermally expandable sheet made of the fire-resistant resin composition. [Background technology]

[0002] In the field of construction, fireproof materials are used in building materials such as fittings, pillars, and wall materials for fire prevention. As fireproof materials, fireproof sheets formed from fireproof resin compositions in which thermally expandable graphite is blended with resin in addition to flame retardants, inorganic fillers, etc. are used (see, for example, Patent Document 1). Such fireproof sheets expand when heated, and the combustion residue forms a fireproof insulation layer, thereby exhibiting fireproof insulation performance. Also, fire-resistant resin compositions containing plasticizers such as phthalate ester-based plasticizers in addition to resins, flame retardants, thermally expandable graphite, etc. are used (see, for example, Patent Document 2). By containing a plasticizer, the sheet formability and winding properties of the fire-resistant resin composition are improved, improving workability. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-141463 A [Patent Document 2] JP 2017-061690 A Summary of the Invention [Problem to be solved by the invention]

[0004] Although fire-resistant resin compositions containing plasticizers have good sheet formability, etc., when the sheet comes into contact with water or is used under high humidity conditions, there are problems such as the flame retardant being easily eluted, causing deterioration of the surface condition of the sheet and a decrease in fire resistance. Therefore, an object of the present invention is to provide a fire-resistant resin composition that has good moldability and excellent water resistance by suppressing the elution of a flame retardant, and a thermally expandable sheet made of the fire-resistant resin composition. [Means for solving the problem]

[0005] As a result of intensive research to solve the above problems, the present inventors have found that the above problems can be solved by using a specific type of flame retardant (A) as a flame retardant in a fire-resistant resin composition containing a resin, thermally expandable graphite, a plasticizer, and a flame retardant, and have completed the present invention. That is, the present invention is as follows. [1] A fire-resistant resin composition comprising a resin, thermally expandable graphite, a plasticizer, and at least one flame retardant (A) selected from a red phosphorus-based flame retardant and a phosphazene-based flame retardant. [2] The fire-resistant resin composition according to the above [1], wherein the content of the flame retardant (A) is 0.05 to 1 in terms of mass ratio to the content of the thermally expandable graphite. [3] The fire-resistant resin composition according to the above [1] or [2], further comprising an inorganic filler. [4] The fire-resistant resin composition according to the above [3], which contains 10 to 200 parts by mass of an inorganic filler per 100 parts by mass of the resin. [5] The fire-resistant resin composition according to any one of the above [1] to [4], which contains 50 to 200 parts by mass of thermally expandable graphite per 100 parts by mass of the resin. [6] The fire-resistant resin composition according to any one of the above [1] to [5], further comprising an organic phosphorus compound. [7] The fire-resistant resin composition according to any one of the above [1] to [6], wherein the resin is a polyvinyl chloride resin. [8] A thermally expandable sheet comprising the fire-resistant resin composition according to any one of [1] to [7] above. Effect of the Invention

[0006] According to the present invention, it is possible to provide a fire-resistant resin composition having good moldability and excellent water resistance, and a thermally expandable sheet made of the fire-resistant resin composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] [Fire-resistant resin composition] The fire-resistant resin composition of the present invention is a fire-resistant resin composition comprising a resin, thermally expandable graphite, a plasticizer, and at least one flame retardant (A) selected from red phosphorus-based flame retardants and phosphazene-based flame retardants. In general, a fire-resistant resin composition containing a resin, thermally expandable graphite, a plasticizer, and a flame retardant has good moldability due to the inclusion of the plasticizer, but since the resin is softened by the plasticizer, the flame retardant is easily eluted by contact with water, etc. The fire-resistant resin composition of the present invention uses at least one flame retardant selected from a red phosphorus-based flame retardant and a phosphazene-based flame retardant, and therefore the amount of eluted flame retardant can be reduced and water resistance is improved.

[0008] (Flame retardant (A)) The fire-resistant resin composition of the present invention contains at least one flame retardant (A) selected from red phosphorus-based flame retardants and phosphazene-based flame retardants. By using such a specific flame retardant (A), the water resistance of the fire-resistant composition and the thermally expandable sheet made of the same is improved.

[0009] As the red phosphorus-based flame retardant, red phosphorus that is generally commercially available can be used as the red phosphorus-based flame retardant. As the red phosphorus-based flame retardant, red phosphorus alone or stabilized red phosphorus can be used. Among these, it is preferable to use stabilized red phosphorus from the viewpoint of suppressing elution from the fire-resistant resin composition by water or the like and from the viewpoint of preventing oxidation. Stabilized red phosphorus is red phosphorus whose surface is coated with a resin, an inorganic substance, or the like. The resin is preferably a thermosetting resin, and specific examples thereof include phenol resin, urea resin, melamine resin, furfuryl alcohol resin, and epoxy resin. The inorganic substances include Fe, Ni, Co, Cu, Zn, Mg, Al, Ti, Zr, and Si. Examples of the metals include metals such as Mn, alloys of these metals, and oxides or hydroxides of these metals.

[0010] The red phosphorus-based flame retardant may be used in the form of a masterbatch in order to improve the water resistance and handling of the fire-resistant resin composition. For example, a resin such as a polyamide resin, a polyester resin, a polyolefin resin, an epoxy resin, or a phenol resin may be mixed with the red phosphorus-based flame retardant to form a resin-mixed red phosphorus masterbatch, or an inorganic substance such as aluminum hydroxide may be further added to and mixed with the resin and the red phosphorus-based flame retardant to form an inorganic and resin-mixed red phosphorus masterbatch.

[0011] In addition, the content of the flame retardant (A) described later means the content of the red phosphorus-based flame retardant itself in the case of a red phosphorus-based flame retardant. Therefore, when a master batch is used, the content of the resin and inorganic matter mixed with the red phosphorus-based flame retardant in the master batch is not included in the content of the flame retardant (A).

[0012] In the present invention, examples of red phosphorus that can be suitably used include "Hishiguard TP-10", "Hishiguard CP-A15", "Hishiguard LP-F", "Hishiguard Master EP-15", and "Hishiguard Safe PM-13", all of which are commercially available from Nippon Chemical Industry Co., Ltd.

[0013] The phosphazene flame retardant is a compound having a -P=N- bond in the molecule. From the viewpoint of suppressing elution from the fire-resistant resin composition by water, the phosphazene flame retardant is preferably one represented by the following general formula (1): [ka] In the above formula (1), R 1 ~R 6 Each independently represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an amino group, or a halogen atom. The halogen atom is preferably a bromine atom. 1 ~R 6When two or more of these are halogen atoms, it is preferable that any one of the halogen atoms is a bromine atom, and it is preferable that all of the halogen atoms are bromine atoms. From the viewpoint of suppressing the elution of flame retardants from the fire-resistant composition by water and from the viewpoint of improving fire resistance, 1 ~R 6 Among these, preferably one or more are halogen atoms, more preferably three or more are halogen atoms, and even more preferably five are halogen atoms. R 1 ~R 6 When five of the groups are halogen atoms, the remaining one is preferably an alkoxy group having 1 to 12 carbon atoms or an aryloxy group having 6 to 12 carbon atoms. In this case, the number of carbon atoms in the alkoxy group is preferably 1 to 10, more preferably 1 to 3. The number of carbon atoms in the aryloxy group is preferably 6 to 10, more preferably 6 to 8. The aryloxy group is further preferably a phenoxy group.

[0014] As the phosphazene-based flame retardant, the compounds represented by the following formulas (2) and (3) are particularly preferred from the viewpoint of further suppressing elution with water. [ka] [ka]

[0015] In the present invention, examples of the phosphazene-based flame retardant that can be suitably used include "HISHICOLIN E" and "HISHICOLIN O" commercially available from Nippon Chemical Industry Co., Ltd.

[0016] The content of the flame retardant (A) is preferably 0.05 to 1, more preferably 0.20 to 0.95, even more preferably 0.40 to 0.90, and even more preferably 0.60 to 0.90, in terms of mass ratio to the content of the thermally expandable graphite. If the content is equal to or greater than these lower limits, the shape retention of the expandable heat insulating layer formed by the expansion of the thermally expandable graphite is likely to be good, and if the content is equal to or less than these upper limits, a decrease in the expansion ratio can be suppressed. By adjusting the content of the flame retardant (A) as described above, the shape of the expandable heat insulating layer formed by the expansion of the thermally expandable graphite is likely to be retained, and the expansion ratio can be made relatively large, so that the fire resistance of the fire-resistant resin composition and the heat-expandable sheet made therefrom is likely to be improved.

[0017] The content of the flame retardant (A) in the fire-resistant resin composition is not particularly limited, and is, for example, preferably 5 to 300 parts by mass, more preferably 20 to 200 parts by mass, even more preferably 30 to 150 parts by mass, and even more preferably 40 to 100 parts by mass, relative to 100 parts by mass of the resin. By making the content of the flame retardant (A) equal to or more than these lower limits, the fire resistance of the fire-resistant resin composition is improved, and by making it equal to or less than these upper limits, the processability of the fire-resistant resin composition is easily improved, and the elution of the flame retardant by water can be suppressed.

[0018] The fire-resistant resin composition of the present invention may contain a flame retardant (B) other than the above-mentioned flame retardant (A) within the range that does not impair the effects of the present invention. The flame retardant (B) may be any flame retardant other than the above-mentioned red phosphorus-based flame retardants and phosphazene-based flame retardants, and examples of the flame retardant include phosphorus-based flame retardants such as ammonium polyphosphate, melamine phosphate, and melamine pyrophosphate, and halogen-based flame retardants. The content of the flame retardant (A) relative to the total amount of the flame retardant (A) and the flame retardant (B) is preferably 50 mass% or more, more preferably 80 mass% or more, even more preferably 95 mass% or more, and even more preferably 100 mass%.

[0019] (Thermal Expandable Graphite) The fire-resistant resin composition of the present invention contains thermally expandable graphite. When the fire-resistant resin composition contains thermally expandable graphite, the thermally expandable graphite expands when the temperature reaches a certain level or higher, forming an expandable heat insulating layer, thereby improving fire resistance. Thermally expandable graphite is a conventionally known substance that expands when heated, and is produced by treating raw material powders such as natural scaly graphite, pyrolytic graphite, and kish graphite with a strong oxidizing agent to produce a graphite intercalation compound. Examples of the strong oxidizing agent include inorganic acids such as concentrated sulfuric acid, nitric acid, and selenic acid, concentrated nitric acid, perchloric acid, perchlorates, permanganates, dichromates, and hydrogen peroxide. Thermally expandable graphite is a crystalline compound that maintains the layered structure of carbon.

[0020] The thermally expandable graphite may be subjected to a neutralization treatment. That is, the thermally expandable graphite obtained by treating with a strong oxidizing agent or the like as described above may be further neutralized with ammonia, an aliphatic lower amine, an alkali metal compound, an alkaline earth metal compound, or the like.

[0021] The particle size of the thermally expandable graphite is preferably 20 to 200 mesh. If the particle size is 200 mesh or smaller, the degree of expansion of the graphite is sufficient to obtain an expandable heat insulating layer, and if the particle size is 20 mesh or larger, the dispersibility when blended with a resin is good, and the physical properties are good. The particle size is measured using a sieve in accordance with JISZ8801-1.

[0022] The content of the thermally expandable graphite is not particularly limited, but is preferably 50 to 200 parts by mass, and more preferably 60 to 150 parts by mass, relative to 100 parts by mass of the resin. When the content is 50 parts by mass or more, it becomes easier to obtain an expansion suitable for preventing the passage of fire, and when the content is 200 parts by mass or less, the processability of the fire-resistant resin composition and the thermally expandable sheet made of the same becomes good.

[0023] (resin) The resin contained in the fire-resistant resin composition of the present invention includes a thermoplastic resin, an elastomer, a rubber, and a combination thereof. Examples of thermoplastic resins include polyolefin resins such as polypropylene resin, polyethylene resin, poly(1-)butene resin, and polypentene resin, polyester resins such as polyethylene terephthalate, polystyrene resin, acrylonitrile-butadiene-styrene (ABS) resin, ethylene-vinyl acetate copolymer (EVA), polycarbonate resin, polyphenylene ether resin, (meth)acrylic resin, polyamide resin, polyvinyl chloride resin (PVC), novolac resin, polyurethane resin, and synthetic resins such as polyisobutylene.

[0024] Examples of the elastomer include olefin-based elastomers, styrene-based elastomers, ester-based elastomers, amide-based elastomers, and vinyl chloride-based elastomers.

[0025] Examples of rubber include natural rubber, isoprene rubber, butadiene rubber, 1,2-polybutadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, chlorinated butyl rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber (EPDM), chlorosulfonated polyethylene, acrylic rubber, epichlorohydrin rubber, multi-vulcanized rubber, non-vulcanized rubber, silicone rubber, fluororubber, and urethane rubber.

[0026] Among the above-mentioned thermoplastic resins, elastomers, and rubbers, the thermoplastic resins are particularly preferred from the viewpoint of improving processability. The thermoplastic resins may be used in combination with at least one of the elastomers and the rubbers, or may be used alone. Among the thermoplastic resins, at least one selected from polyethylene resin, ethylene vinyl acetate copolymer (EVA), and polyvinyl chloride resin is preferred. Among these, polyvinyl chloride resin is more preferred from the viewpoint of reducing the proportion of carbon contained therein in terms of fire resistance. In general, when polyvinyl chloride resin is used, a plasticizer is necessary from the viewpoint of improving the moldability of the fire-resistant resin composition into a sheet or the like, but when a plasticizer is contained, the flame retardant is easily dissolved by water as described above. However, even in such a case, by using a specific flame retardant as in the present invention, the dissolution by water can be suppressed. That is, in the present invention, when polyvinyl chloride resin is used as the resin, a fire-resistant resin composition having an extremely good balance of physical properties such as fire resistance, moldability, and water resistance is obtained.

[0027] The polyvinyl chloride resin may be a vinyl chloride homopolymer or a vinyl chloride copolymer, which is a copolymer of vinyl chloride and a monomer having an unsaturated bond copolymerizable with vinyl chloride and contains 50% by mass or more of a constituent unit derived from vinyl chloride. Examples of monomers having an unsaturated bond copolymerizable with vinyl chloride include vinyl esters such as vinyl acetate and vinyl propionate, acrylic acid, methacrylic acid, acrylic acid esters such as methyl acrylate and ethyl acrylate, methacrylic acid esters such as methyl methacrylate and ethyl methacrylate, olefins such as ethylene and propylene, aromatic vinyls such as acrylonitrile and styrene, and vinylidene chloride. The polyvinyl chloride resin may be a polychlorinated vinyl chloride resin, which is a polychlorinated vinyl chloride resin obtained by chlorinating a vinyl chloride homopolymer, a vinyl chloride copolymer, or the like. The polyvinyl chloride resin may be used alone or in combination of two or more of the above-mentioned resins.

[0028] The average degree of polymerization of the polyvinyl chloride resin is not particularly limited, but is preferably 400 to 3000. By making the average degree of polymerization 400 or more, the mechanical properties of the thermally expandable sheet become good. Furthermore, by making the average degree of polymerization 3000 or less, the processability tends to become good. From these viewpoints, the average degree of polymerization is more preferably 700 to 1500. The average degree of polymerization is measured in accordance with JIS K6720-2.

[0029] (Plasticizer) The fire-resistant resin composition of the present invention contains a plasticizer. By containing the plasticizer, the fire-resistant resin composition has good moldability into a sheet or the like. The plasticizer is preferably used in combination with a thermoplastic resin as the above-mentioned resin, and more preferably used in combination with a polyvinyl chloride resin. Generally, the plasticizer used is a liquid component that is liquid at room temperature (23°C) and normal pressure (1 atmosphere).

[0030] Specific examples of the plasticizer include phthalate-based plasticizers such as di-2-ethylhexyl phthalate (DOP), di-n-octyl phthalate, diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), diundecyl phthalate (DUP), or phthalate esters of higher alcohols or mixed alcohols having about 10 to 13 carbon atoms, di-2-ethylhexyl adipate (DOA), diisobutyl adipate (DIBA), dibutyl adipate (DBA), di-n-octyl adipate, di-n-decyl adipate, diisodecyl adipate, di-2-ethylhexyl azelate, dibutyl sebacate, and di-2-ethylhexyl sebacate. Examples of the plasticizer include aliphatic ester-based plasticizers, trimellitic acid ester-based plasticizers such as tri-2-ethylhexyl trimellitate (TOTM), tri-n-octyl trimellitate, tridecyl trimellitate, triisodecyl trimellitate, and di-n-octyl-n-decyl trimellitate, biphenyl tetracarboxylic acid tetraalkyl ester-based plasticizers such as 2,3,3',4'-biphenyl tetracarboxylic acid tetraheptyl ester, polyester-based polymer plasticizers, epoxy-based plasticizers such as epoxidized soybean oil, epoxidized linseed oil, epoxidized cottonseed oil, and liquid epoxy resins, chlorinated paraffin, and chlorinated fatty acid esters such as pentachlorostearic acid alkyl esters. These plasticizers may be used alone or in combination of two or more kinds. Among the above plasticizers, phthalic acid plasticizers are preferred from the viewpoints of flame retardancy and economy. The phthalic acid plasticizers may be used alone or in combination with phosphate ester plasticizers.

[0031] The content of the plasticizer is preferably 30 to 130 parts by mass, more preferably 40 to 120 parts by mass, and even more preferably 50 to 100 parts by mass, relative to 100 parts by mass of the resin. When the content of the plasticizer is equal to or more than these lower limits, the moldability of the fire-resistant resin composition into a sheet or the like is improved, and when the content is equal to or less than these upper limits, the sheet can be prevented from becoming too soft.

[0032] The total content of the above-mentioned resin, flame retardant, thermally expandable graphite, and plasticizer is preferably 40 mass% or more, preferably 60 mass% or more, and more preferably 70 mass% or more, and is preferably 98 mass% or less, and preferably 95 mass% or less, based on the total amount of the fire-resistant resin composition.

[0033] (Organophosphorus compounds) The fire-resistant resin composition of the present invention preferably contains an organic phosphorus-based compound other than the above-mentioned flame retardant as a dispersant. By containing an organic phosphorus-based compound, the fire resistance of the fire-resistant resin composition is improved. It is believed that by containing an organic phosphorus-based compound, the flame retardant is appropriately arranged around the thermally expandable graphite, and the shape of the expansion heat insulating layer, which is the expansion residue, is easily maintained. As the organic phosphorus-based compound, a phosphoric acid ester-based compound is preferred from the viewpoint of further improving the fire resistance of the fire-resistant resin composition.

[0034] Examples of the phosphoric acid ester compound include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, tributoxyethyl phosphate, trichloroethyl phosphate, tris(2-chloropropyl)phosphate, tris(2,3-dichloropropyl)phosphate, tris(2,3-dibromopropyl)phosphate, tris(bromochloropropyl)phosphate, bis(2,3-dibromopropyl)-2,3-dichloropropyl phosphate, bis(chloropropyl)monoctyl phosphate, tris(2-ethylhexyl)phosphate, triphenyl phosphate, tricresyl phosphate (TCP), trixylenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, etc. Among these, trixylenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, and tricresyl phosphate (TCP) are particularly preferred.

[0035] The content of the organic phosphorus compound is not particularly limited, but from the viewpoint of increasing the dispersibility of the flame retardant and further improving the fire resistance of the fire-resistant resin composition, it is preferably 0.1 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 2 to 10 parts by mass relative to 100 parts by mass of the resin.

[0036] (Inorganic filler) The fire-resistant resin composition of the present invention preferably contains an inorganic filler, which, when heated to form an expandable insulation layer, increases the heat capacity and suppresses heat transfer while acting as an aggregate to improve the strength of the expandable insulation layer. The inorganic filler is not particularly limited, and examples thereof include metal oxides such as alumina, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, and ferrite; metal hydroxides such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, and hydrotalcite; metal carbonates such as basic magnesium carbonate, calcium carbonate, magnesium carbonate, zinc carbonate, strontium carbonate, and barium carbonate; calcium sulfate, gypsum fiber, and calcium salts such as calcium silicate; silica, diatomaceous earth, dawsonite, barium sulfate, talc, clay, mica, montmorillonite, bentonite, activated clay, sepiolite, imogolite, sericite, glass fiber, glass beads, silica-based balloons, aluminum nitride, boron nitride, silicon nitride, carbon black, graphite, carbon fiber, carbon balloons, various metal powders, potassium titanate, magnesium sulfate, lead zirconate titanate, aluminum borate, molybdenum sulfide, silicon carbide, stainless steel fiber, zinc borate, various magnetic powders, slag fiber, and fly ash. The inorganic fillers may be used alone or in combination of two or more. Among these, at least one selected from metal oxides and metal carbonates is preferred.

[0037] The particle size of the inorganic filler is preferably 0.5 to 100 μm, more preferably 1 to 50 μm. By making it equal to or greater than these lower limits, secondary aggregation is prevented and dispersibility is improved. In addition, by making it equal to or greater than the lower limits, the viscosity of the fire-resistant resin composition can be reduced, and processability is likely to be improved. In addition, by making it equal to or less than the upper limits, the surface properties and mechanical performance of the thermally expandable sheet formed from the fire-resistant resin composition are improved. The particle size of the inorganic filler is determined by observing an SEM (scanning electron microscope image) to determine the particle size distribution, and in the volumetric particle size distribution obtained from that, the particle size of 50% of the particles passing through from the small particle size side is determined as the average particle size.

[0038] The content of the inorganic filler is preferably 10 to 200 parts by mass, and more preferably 15 to 150 parts by mass, relative to 100 parts by mass of the resin. When the content of the inorganic filler is 10 parts by mass or more, the fire resistance of the fire-resistant resin composition is improved. When the content is 200 parts by mass or less, the processability is improved and the mechanical properties are easily maintained at a good level.

[0039] The fire-resistant resin composition of the present invention may contain other components in addition to those described above. Examples of other components include various additives such as phenol-based, amine-based, and sulfur-based antioxidants, metal inhibitors, antistatic agents, stabilizers, crosslinking agents, lubricants, softeners, and pigments, provided that the physical properties of the composition are not impaired.

[0040] [Thermal expansion sheet] The thermally expandable sheet of the present invention is made of the above-mentioned fire-resistant resin composition. In the thermally expandable sheet, the thermally expandable graphite expands when heated to form an expandable insulating layer. The thermally expandable sheet functions as a fire-resistant material by insulating the sheet when exposed to high temperatures such as during a fire due to the expandable insulating layer. The thermally expandable sheet has an expansion ratio of 3 to 50 times after being heated at 600°C for 120 minutes, for example. The expansion ratio is calculated as (thickness of test piece after heating) / (thickness of test piece before heating) of a test piece of the thermally expandable sheet.

[0041] The thickness of the thermally expandable sheet is not particularly limited, but from the viewpoints of fire resistance and ease of handling, the thickness is preferably 0.2 to 10 mm, and more preferably 0.5 to 3.0 mm.

[0042] (Method of manufacturing thermal expansion sheet) The thermally expandable sheet of the present invention can be produced, for example, as follows. First, predetermined amounts of resin, thermally expandable graphite, flame retardant, plasticizer and other additives which are added as required are kneaded in a kneading machine such as a kneading roll to obtain a fire-resistant resin composition. Next, when the resin is a thermoplastic resin, a rubber, an elastomer, or a combination thereof, the obtained fire-resistant resin composition is molded into a sheet by a known molding method such as press molding, calendar molding, extrusion molding, etc., to obtain a thermally expandable sheet. When the resin contains a thermosetting resin, the obtained fire-resistant resin composition may be heated and pressurized, for example, by press molding, to form a sheet and thermally cure the sheet to obtain a thermally expandable sheet.

[0043] (Laminated sheet) The thermally expandable sheet of the present invention may be laminated with other sheet members or pressure-sensitive adhesive layers to form a laminate sheet. The laminate sheet includes, for example, a substrate and a thermally expandable sheet laminated on one or both sides of the substrate. The substrate is usually a woven fabric or nonwoven fabric. The fibers used for the woven fabric or nonwoven fabric are not particularly limited, but are preferably non-combustible or semi-non-combustible materials, such as glass fibers, ceramic fibers, cellulose fibers, polyester fibers, carbon fibers, graphite fibers, and thermosetting resin fibers. The laminate sheet can be obtained, for example, by forming the fire-resistant resin composition into a sheet on a substrate and, if necessary, by thermally curing the fire-resistant resin composition.

[0044] The laminate sheet may include a thermally expandable sheet and a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer may be laminated on one or both sides of the thermally expandable sheet, for example. Furthermore, the laminate sheet may include a thermally expandable sheet, a substrate, and an adhesive layer. Such a laminate sheet may have a thermally expandable sheet on one side of the substrate and an adhesive layer on the other side, or a thermally expandable sheet and an adhesive layer may be provided in this order on one side of the substrate. The adhesive layer can be formed, for example, by transferring an adhesive coated on a release paper to the laminate sheet.

[0045] The fire-resistant resin composition of the present invention, the thermally expandable sheet and the laminated sheet made of the fire-resistant resin composition can each be used as a fire-resistant material. Specifically, each of these can be used in various buildings such as detached houses, apartment buildings, high-rise houses, high-rise buildings, commercial facilities, public facilities, various vehicles such as automobiles and trains, ships, aircraft, etc. The fire-resistant resin composition of the present invention has excellent water resistance, so it is preferably used for members exposed to rain or members with high humidity due to condensation, etc., and is preferably used for buildings among the above. Specifically, the buildings can be used for walls, beams, columns, floors, bricks, roofs, boards, windows, shoji screens, doors, doors, sliding doors, transoms, wiring, piping, etc., but are not limited thereto. EXAMPLES

[0046] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these.

[0047] The expansion ratio, residual hardness, elution rate, and moldability were evaluated as follows. (Expansion ratio) Test pieces (length 100 mm, width 100 mm, thickness 1.6 mm) made from the obtained thermally expandable sheets of the Examples and Comparative Examples were placed on the bottom of a stainless steel holder (101 mm square, height 80 mm), fed into an electric furnace, and heated at 600°C for 30 minutes. Thereafter, the height (highest part), width, length, and thickness of the test pieces were measured, and the expansion ratio was calculated by ((thickness of test piece after heating) / (thickness of test piece before heating)). (residue hardness) The heated test piece after measuring the expansion ratio was fed into a compression testing machine (Kato Tech Co., Ltd., "Finger Feeling Tester") and compressed at a speed of 0.1 cm / sec with a three-point indenter with a diameter of 1 mm. The maximum stress up to 10 mm compression from the top surface of the residue was measured, and the compressive strength of the test piece after combustion was measured. (Flame retardant elution rate) Five test pieces (length 50 mm, width 50 mm, thickness 1.5 mm) made from the obtained thermally expandable sheets of the Examples and Comparative Examples were immersed in 200 g of pure water in a sealed container at 60° C. for one week, and then the samples were taken out and the pure water was evaporated and dried at 60° C. for 96 hours, and the mass of the precipitate that formed was measured. The dissolution rate was measured using this value. (Moldability) Under the conditions of each Example and Comparative Example, the case where the thermally expandable sheet could be molded was rated as "G", and the case where the thermally expandable sheet could not be molded was rated as "B".

[0048] (Examples 1 to 10, Comparative Example 1) According to the composition shown in Table 1 below, resin, flame retardant, thermally expandable graphite, inorganic filler, plasticizer, and dispersant were put into a roll and kneaded at 130°C for 5 minutes to obtain a fire-resistant resin composition. The obtained fire-resistant resin composition was press-molded at 130°C for 3 minutes to obtain a heat-expandable sheet having a thickness of 1.6 mm. The components used in each of the examples and comparative examples are as follows.

[0049] Comparative Example 2 Resin, flame retardant, thermally expandable graphite, inorganic filler, and dispersant were put into a roll and kneaded at 180 ° C for 5 minutes according to the composition shown in Table 1 below to obtain a fire-resistant resin composition. The obtained fire-resistant resin composition was press-molded at 180 ° C for 3 minutes, but the fire-resistant resin composition was hard and could not be molded into a heat-expandable sheet. In addition, press molding was attempted at 220 ° C, but the heat-expandable graphite expanded, the surface properties were deteriorated, and coarse bubbles were generated inside, making it impossible to obtain the desired heat-expandable sheet. Table 1 shows the results of measuring the expansion ratio, residual hardness, and elution rate of the molded product obtained by press molding at 220 ° C.

[0050] (1) Resin PVC: Polyvinyl chloride resin, manufactured by Shin-Etsu Chemical Co., Ltd., product name "TK-1000", average degree of polymerization 1030 (2) Flame retardants Red phosphorus 1: Product name "Hishiguard TP-10" manufactured by Nippon Chemical Industry Co., Ltd. Stabilized red phosphorus, red phosphorus content over 90% Red phosphorus 2: Product name "Hishiguard CP-A15" manufactured by Nippon Chemical Industry Co., Ltd. Stabilized red phosphorus, red phosphorus content 85% or more Red phosphorus 3: Manufactured by Nippon Chemical Industry Co., Ltd., product name "Hishiguard LP-F" Stabilized red phosphorus, red phosphorus content 85% or more Red phosphorus 4: Product name "Hishiguard Master EP-15" manufactured by Nippon Chemical Industry Co., Ltd. Masterbatch (red phosphorus content 48.5%) Red phosphorus 5: Manufactured by Nippon Chemical Industry Co., Ltd., product name "Hishi Guard Safe PM-13" Masterbatch (red phosphorus content 32.5%) Phosphazene flame retardant: Nippon Chemical Industry Co., Ltd., product name "HISHICOLIN E" Phosphazene flame retardant: Nippon Chemical Industry Co., Ltd., product name "HISHICOLIN O" Ammonium polyphosphate: Clariant Japan Co., Ltd., product name "AP422" (3) Thermally expandable graphite: Air Water Corporation, product name "CA-60N" (4) Inorganic fillers Calcium carbonate: Shiraishi Calcium Co., Ltd., product name "BF300" Zinc oxide: Sakai Chemical Industry Co., Ltd., product name "Zinc oxide type 1" (5) Plasticizers DOP: Di-2-ethylhexyl phthalate, DOP manufactured by J-Plus Corporation (6) Dispersants TCP: Tricresyl phosphate, TCP manufactured by Daihachi Chemical Co., Ltd.

[0051] [Table 1]

[0052] As shown in the above examples, the thermally expandable sheet made of the fire-resistant resin composition of the present invention contains a specific flame retardant (A), and therefore the elution of the flame retardant upon contact with water is suppressed, and the sheet has excellent water resistance and good moldability. In contrast, the heat-expandable sheet of Comparative Example 1 did not contain the specific flame retardant (A), and the flame retardant was easily dissolved when it came into contact with water, and the water resistance was poor. In addition, the fire-resistant resin composition of Comparative Example 2, which did not use a plasticizer, could not be molded into a heat-expandable sheet.

Claims

1. The flame retardant (A) comprises a resin, thermally expandable graphite, a plasticizer, and at least one flame retardant (A) selected from a red phosphorus-based flame retardant and a phosphazene-based flame retardant; The resin is a polyvinyl chloride resin, A heat-expandable fire-resistant resin composition for fire-resistant materials, comprising 50 to 200 parts by mass of the heat-expandable graphite per 100 parts by mass of the resin.

2. The heat-expandable fire-resistant resin composition for fire-resistant materials according to claim 1, wherein the content of the flame retardant (A) is 0.05 to 1 in mass ratio relative to the content of the heat-expandable graphite.

3. The heat-expandable fire-resistant resin composition for fire-resistant materials according to claim 1 or 2, further comprising an inorganic filler.

4. The heat expandable fire-resistant resin composition for fire-resistant materials according to claim 3, comprising 10 to 200 parts by mass of an inorganic filler relative to 100 parts by mass of the resin.

5. The heat-expandable fire-resistant resin composition for fire-resistant materials according to any one of claims 1 to 4, further comprising an organic phosphorus compound.

6. A heat-expandable sheet for fire-resistant materials comprising the heat-expandable fire-resistant resin composition for fire-resistant materials according to any one of claims 1 to 5.

7. The thermally expandable sheet for fire-resistant materials according to claim 6, which is used as a fire-resistant material for buildings.

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