JP7201373B2 - Fire resistant resin composition and thermally expandable sheet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fire resistant resin composition and a thermally expandable sheet comprising the fire resistant resin composition.

In the construction field, fireproof materials are used for building materials such as fittings, columns, and wall materials for fire prevention. As a refractory material, a refractory sheet or the like in which thermally expandable graphite is blended with a resin in addition to a flame retardant, an inorganic filler, and the like is used (see, for example, Patent Document 1). Such a refractory material expands when heated, and the combustion residue forms a refractory and heat insulating layer, thereby exhibiting refractory and heat insulating performance.
The performance required for fireproof materials differs depending on the application. In general, fireproof facilities such as sashes and doors are required to be fireproof for about 20 minutes, and when used for pillars, beams, walls, etc. Fire resistance of time is required.

JP 2017-141463 A

Conventional refractory materials containing thermally expandable graphite have good fire resistance performance in a relatively short period of time. There is a problem that the fire resistance is lowered due to this.
Accordingly, an object of the present invention is to provide a fire-resistant resin composition having excellent long-term fire resistance, and a thermally expandable sheet comprising the fire-resistant resin composition.

As a result of intensive studies to solve the above problems, the present inventors have found that, in a fire resistant resin composition containing a resin, thermally expandable graphite, and a flame retardant, the decomposition temperature of the flame retardant contained in the fire resistant resin composition The present inventors have found that the above problems can be solved by adjusting the difference between the expansion starting temperature of the thermally expandable graphite and the expansion start temperature of the thermally expandable graphite to a certain value or more, and have completed the present invention. That is, the present invention is as follows.
[1] A fire resistant resin composition containing a resin, thermally expandable graphite, and a flame retardant, wherein the difference between the decomposition temperature of the flame retardant and the expansion start temperature of the thermally expandable graphite (the decomposition temperature of the flame retardant - A fire-resistant resin composition characterized in that the expansion start temperature of thermally expandable graphite) is 100°C or higher.
[2] The fire-resistant resin composition according to [1] above, wherein the content of the flame retardant is 0.05 to 1 in mass ratio to the content of the thermally expandable graphite.
[3] The fire-resistant resin composition according to [1] or [2] above, wherein the flame retardant is one or more selected from the group consisting of phosphorus flame retardants and brominated flame retardants.
[4] The fire-resistant resin composition according to any one of [1] to [3] above, further comprising an organic phosphorus compound other than the flame retardant.
[5] The fire-resistant resin composition according to [4] above, wherein the organic phosphorus compound is a phosphate ester compound.
[6] The fire-resistant resin composition according to any one of [1] to [5] above, which further contains an inorganic filler.
[7] The fire-resistant resin composition according to [6] above, which contains 10 to 200 parts by mass of an inorganic filler with respect to 100 parts by mass of the resin.
[8] The fire-resistant resin composition according to any one of [1] to [7] above, which contains 50 to 200 parts by mass of the thermally expandable graphite with respect to 100 parts by mass of the resin.
[9] The fire-resistant resin composition according to any one of [1] to [8] above, wherein the resin is a polyvinyl chloride resin.
[10] A thermally expandable sheet made of the fire-resistant resin composition according to any one of [1] to [9] above.

ADVANTAGE OF THE INVENTION According to this invention, the heat-expandable sheet|seat which consists of the fire resistant resin composition and this fire resistant resin composition which are excellent in long-term fire resistance can be provided.

[Fire-resistant resin composition]
The fire resistant resin composition of the present invention contains a resin, thermally expandable graphite, and a flame retardant, and the difference between the decomposition temperature of the flame retardant and the expansion start temperature of the thermally expandable graphite (the decomposition temperature of the flame retardant - The expansion start temperature of thermally expandable graphite) is 100° C. or higher. In this specification, the difference between the decomposition temperature of the flame retardant and the expansion start temperature of the thermally expandable graphite is the value obtained by subtracting the expansion start temperature of the thermally expandable graphite from the decomposition temperature of the flame retardant.
Although the reason why the fire-resistant resin composition of the present invention has excellent long-term fire resistance is not clear, it is presumed as follows. The thermally expandable graphite contained in the refractory resin composition expands at a temperature equal to or higher than the expansion start temperature to form an expandable heat insulating layer. If the flame retardant decomposes when the thermally expandable graphite does not expand sufficiently, the uniformity of the flame retardant properties on the surface of the expansive thermal insulation layer cannot be maintained, and the shape retention of the expansive thermal insulation layer deteriorates over time, resulting in fire resistance. sexuality worsens. On the other hand, if the decomposition temperature of the flame retardant is sufficiently higher than the expansion start temperature of the thermally expandable graphite, the flame retardant will decompose after the thermally expandable graphite has expanded sufficiently, resulting in expansion insulation. A uniform flame-retardant layer is formed around the layer surface. As a result, it is considered that the shape of the expandable heat insulating layer is likely to be maintained for a long period of time, and the fire resistance is enhanced.

In the fire-resistant resin composition of the present invention, the difference between the decomposition temperature of the flame retardant and the expansion start temperature of the thermally expandable graphite is 100°C or more. When the difference between the decomposition temperature of the flame retardant and the expansion start temperature of the thermally expandable graphite is less than 100°C, the fire resistance of the fire resistant resin composition is lowered. From the viewpoint of improving the fire resistance of the fire resistant resin composition, the difference between the decomposition temperature of the flame retardant and the expansion start temperature of the thermally expandable graphite is preferably 120° C. or more, more preferably 140° C. or more. It is more preferably 200° C. or higher. In addition, from the viewpoint that the flame retardant decomposes appropriately during combustion and the flame retardant effect is exhibited, the difference between the decomposition temperature of the flame retardant and the expansion temperature of the thermally expandable graphite is preferably 500 ° C. or less, and 400 ° C. or less. is more preferable.

The decomposition temperature of the flame retardant is determined by measuring the temperature at which the mass of the flame retardant decreases by 10% by differential thermal-thermogravimetric simultaneous measurement (TG-DTA), and this temperature is defined as the decomposition temperature.
In addition, the expansion start temperature of the thermally expandable graphite is measured by raising the temperature of the thermally expandable graphite at a constant temperature with a device that measures the force in the normal direction and the temperature adjustment function, and measuring the temperature at which the force in the normal direction rises. It is possible to measure by The measuring device is not limited as long as it can control the measurement temperature and measure the stress in the normal direction. For example, a rheometer can be used.

(Flame retardants)
The flame retardant contained in the fire-resistant resin composition of the present invention is appropriately selected and used from those having a difference of 100° C. or more between the decomposition temperature of the flame retardant and the expansion start temperature of the thermally expandable graphite. can be done. That is, it can be appropriately selected in consideration of the expansion start temperature of the thermally expandable graphite to be used.
The flame retardant can be selected from those having a decomposition temperature of preferably 250 to 600°C, more preferably 320 to 550°C, still more preferably 350 to 500°C. When the decomposition temperature of the flame retardant is at least these lower limits, the difference from the expansion start temperature of the thermally expandable graphite tends to be a certain value or more. , it becomes easier to improve the fire resistance.

The type of flame retardant is not particularly limited as long as the difference between the decomposition temperature of the flame retardant and the expansion start temperature of the thermally expandable graphite is 100° C. or more. Halogen-based flame retardants such as brominated flame retardants and chlorine-based flame retardants may be appropriately selected. From the viewpoint of further enhancing fire resistance, it is preferable to use one or more selected from the group consisting of phosphorus-based flame retardants and bromine-based flame retardants as the flame retardant.

上記式（１）中、Ｒ_１～Ｒ_６はそれぞれ独立に、炭素数１～１２のアルキル基、炭素数１～１２のアルコキシ基、炭素数６～１２のアリールオキシ基、アミノ基、ハロゲン原子のいずれかを示す。
このようなホスファゼン系化合物の例としては、大塚化学社から市販されている「ＳＰＢ－１００」等が挙げられる。 The phosphorus-based flame retardant is not particularly limited as long as it has a difference of 100° C. or more from the expansion temperature of the thermally expandable graphite used. acid melamine/melam/melem, phosphorus-based spiro compounds, phosphazene-based compounds, and the like. Among these, phosphazene-based compounds, phosphorus-based spiro compounds, and the like are more preferable from the viewpoint of having a high decomposition temperature and easily adjusting the difference from the expansion temperature of thermally expandable graphite to a certain level or more.
As the phosphorus-based flame retardant, both an organic phosphorus-based flame retardant and an inorganic phosphorus-based flame retardant can be used, but it is preferable to use an organic phosphorus-based flame retardant.
A phosphazene-based compound is an organic compound having a -P=N- bond in the molecule. As the phosphazene-based compound, a compound represented by the following general formula (1) is preferable because it has a relatively high decomposition temperature.

In the above formula (1), R ₁ to R ₆ are each independently 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, and a halogen atom. indicates either
Examples of such phosphazene compounds include "SPB-100" commercially available from Otsuka Chemical Co., Ltd., and the like.

The phosphorus-based spiro compound is not particularly limited as long as it is a spiro compound having a phosphorus atom. In addition, the spiro compound is a compound having a structure in which two cyclic compounds share one carbon, and the spiro compound having a phosphorus atom means that at least one of the elements constituting the two cyclic compounds is a phosphorus atom. It is a compound.
As the phosphorus-based spiro compound, for example, it is preferable to use a compound having a structural unit represented by the following formula (2) in the molecule.

The brominated flame retardant is not particularly limited as long as the difference between the decomposition temperature of the flame retardant and the expansion temperature of the thermally expandable graphite used is 100 ° C. or more. It may be a retardant or an aromatic brominated flame retardant. Examples of aliphatic brominated flame retardants include tetrabromocyclooctane, hexabromocyclododecane, and trisdibromopropyl phosphate. Examples of aromatic brominated flame retardants include decabromodiphenyl oxide, octabromodiphenyl oxide, brominated bisphenol A flame retardants, and brominated bisphenol S flame retardants. Among these, aromatic flame retardants are preferable, and brominated bisphenol A flame retardants are more preferable, from the viewpoint of having a high decomposition temperature and easily adjusting the difference from the expansion temperature of thermally expandable graphite to a certain level or more. .
The brominated bisphenol A flame retardant may be a compound having a bisphenol A-derived structural unit in which at least one hydrogen atom is substituted with a bromine atom. The brominated bisphenol A flame retardant may have one structural unit, but is preferably a brominated polycarbonate having a plurality of structural units.
From the viewpoint of having a relatively high decomposition temperature, the brominated bisphenol A flame retardant preferably uses a compound having a structural unit represented by the following formula (3).

上記式（４）、（５）において、ｎは１～５０であるが、ｎは好ましくは１～３０であり、より好ましくは５～２０である。 Among the compounds having a structural unit represented by the above formula (3), from the viewpoint of having a high decomposition temperature and easily adjusting the difference from the expansion temperature of thermally expandable graphite to a certain level or more, especially the following formula (4) , it is preferable to use a compound represented by the following formula (5).

In the above formulas (4) and (5), n is 1-50, preferably 1-30, more preferably 5-20.

Examples of such brominated bisphenol A flame retardants include Fireguard 7000, Fireguard 7500 and Fireguard 8500 commercially available from Teijin Limited.
The above flame retardants may be used alone or in combination of two or more.

In addition, the content of the flame retardant is preferably 0.05 to 1, more preferably 0.20 to 0.95, more preferably 0.40 in mass ratio to the content of the thermally expandable graphite. ~0.90 is more preferred, and 0.60 to 0.90 is even more preferred. By adjusting the content of the flame retardant as described above, the shape of the expanded heat insulating layer formed by expansion of the thermally expandable graphite can be easily maintained, and the fire resistance of the fire resistant resin composition and the thermally expandable sheet made of the same can be improved. easier to improve.

The content of the flame retardant in the fire-resistant resin composition is not particularly limited, for example, the flame retardant is preferably 5 to 300 parts by mass, more preferably 20 to 200 parts by mass, with respect to 100 parts by mass of the resin. is more preferable, and 40 to 150 parts by mass is even more preferable. When the content of the flame retardant is 5 parts by mass or more, the fire resistance of the fire resistant resin composition is improved, and when it is 300 parts by mass or less, the processability of the fire resistant resin composition tends to be improved. .

(Thermal expandable graphite)
The fire resistant resin composition of the present invention contains thermally expandable graphite. The thermally expandable graphite may be appropriately selected from those satisfying the requirement that the difference between the decomposition temperature of the flame retardant and the expansion start temperature of the thermally expandable graphite is 100° C. or more.
Thermally expandable graphite is a conventionally known substance that expands when heated, and is produced by acid-treating a raw material powder such as natural flake graphite, pyrolytic graphite, or Kish graphite with a strong oxidizing agent to form a graphite intercalation compound. be. Examples of strong oxidizing agents include inorganic acids such as concentrated sulfuric acid, nitric acid and selenic acid, concentrated nitric acid, perchloric acid, perchlorates, permanganates, bichromates, and hydrogen peroxide. Thermally expandable graphite is a crystalline compound that maintains the layered structure of carbon.

Thermally expandable graphite may be neutralized. That is, the thermally expandable graphite obtained by treatment 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.

The expansion start temperature of the thermally expandable graphite is preferably 150 to 350 ° C., more preferably 170 to 300 ° C., more preferably 180 to 280, from the viewpoint of keeping the difference from the decomposition temperature of the flame retardant at a certain level or more. °C is more preferred. If it is at least these lower limits, it becomes easier to prevent unnecessary thermal expansion when molding the heat-resistant resin composition into a thermally expandable sheet or the like, and if it is at most these upper limits, the difference from the decomposition temperature of the flame retardant becomes easier to adjust above a certain level.

The particle size of the thermally expandable graphite is preferably 20-200 mesh. When the particle size is 200 mesh or less, the degree of expansion of the graphite is sufficient to obtain an expanded heat insulating layer. Good. The particle size was measured using a sieve conforming to JISZ8801-1.

The content of the thermally expandable graphite is not particularly limited, but is preferably 50 to 200 parts by mass, more preferably 60 to 150 parts by mass, based on 100 parts by mass of the resin. When it is 50 parts by mass or more, it becomes easy to obtain an expansion suitable for preventing the passage of fire, and when it is 200 parts by mass or less, the fire-resistant resin composition and the heat-expandable sheet made of the composition have good workability. get better.

(resin)
Resins included in the fire resistant resin composition of the present invention include thermoplastic resins, thermoset resins, elastomers, rubbers, and combinations thereof.
Examples of thermoplastic resins include polyolefin resins such as polypropylene resins, polyethylene resins, poly(1-)butene resins and polypentene resins, polyester resins such as polyethylene terephthalate, polystyrene resins, acrylonitrile-butadiene-styrene (ABS) resins, and ethylene. Synthetic resins such as vinyl acetate copolymer (EVA), polycarbonate resin, polyphenylene ether resin, (meth)acrylic resin, polyamide resin, polyvinyl chloride resin (PVC), novolak resin, polyurethane resin, and polyisobutylene can be used.

Examples of thermosetting resins include synthetic resins such as polyurethane, polyisocyanate, polyisocyanurate, phenol resin, epoxy resin, urea resin, melamine resin, unsaturated polyester resin, and polyimide.

Examples of elastomers include olefin-based elastomers, styrene-based elastomers, ester-based elastomers, amide-based elastomers, vinyl chloride-based elastomers, and the like.

Rubbers 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, polyvulcanized rubber, non-vulcanized rubber, silicone rubber, fluororubber, urethane rubber, and the like.
Among these, silicone rubber, fluororubber, and the like are preferable, and silicone rubber is more preferable, from the viewpoint of reducing the content of carbon in terms of fire resistance.

Among the above thermoplastic resins, thermosetting resins, elastomers, and rubbers, thermoplastic resins are particularly preferred from the viewpoint of improving workability. Thermoplastic resins may be used in combination with at least one of thermosetting resins, elastomers, and rubbers, but may be used alone.
Moreover, among thermoplastic resins, at least one selected from polyethylene resins, ethylene-vinyl acetate copolymers, (EVA), and polyvinyl chloride resins is preferable. Among these resins, polyvinyl chloride resin is more preferable from the viewpoint of lowering the content of carbon in terms of fire resistance.

The polyvinyl chloride resin may be a vinyl chloride homopolymer or a vinyl chloride copolymer. A vinyl chloride-based copolymer 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 structural units derived from vinyl chloride.
Examples of the monomer having an unsaturated bond copolymerizable with vinyl chloride include vinyl esters such as vinyl acetate and vinyl propionate; acrylic acid esters such as acrylic acid, methacrylic acid, methyl acrylate and ethyl acrylate; Examples include 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.
Also, the polyvinyl chloride resin may be a polyvinyl chloride resin. A polyvinyl chloride resin is a polyvinyl chloride resin obtained by chlorinating a vinyl chloride homopolymer, a vinyl chloride copolymer, or the like.
Among the above polyvinyl chloride resins, one may be used alone, or two or more may be used in combination.

Although the average degree of polymerization of the polyvinyl chloride resin is not particularly limited, it is preferably 400-3000. By setting the average degree of polymerization to 400 or more, the mechanical properties of the thermally expandable sheet are improved. In addition, by setting the average degree of polymerization to 3000 or less, workability tends to be improved. From these points of view, the average degree of polymerization is more preferably 700-1500. The average degree of polymerization is measured according to JIS K6720-2.

The total content of the flame retardant, thermally expandable graphite, and resin is preferably 20% by mass or more, preferably 40% by mass or more, preferably 50% by mass, based on the total amount of the fire-resistant resin composition. % or more, preferably 95% by mass or less, preferably 90% by mass or less, and even more preferably 85% by mass or less.

(Organic phosphorus compounds other than flame retardants)
The fire-resistant resin composition of the present invention preferably contains an organic phosphorus compound other than the flame retardant as a dispersant. By containing the organic phosphorus compound, the fire resistance of the fire resistant resin composition is improved. This is probably because the inclusion of the organic phosphorus compound allows the flame retardant to be appropriately arranged around the thermally expandable graphite, making it easier to maintain the shape of the expansion insulation layer, which is the expansion residue. .
Among organic phosphorus compounds, phosphoric acid ester compounds are preferable from the viewpoint of further improving the fire resistance of the fire resistant resin composition.

Phosphate ester compounds include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, octyldiphenyl 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) monooctyl phosphate, tris (2-ethylhexyl) phosphate, triphenyl phosphate, tricresyl phosphate (TCP), trixylenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate and the like. Among these, trixylenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, and tricresyl phosphate (TCP) are particularly preferred.

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

(Inorganic filler)
The fire-resistant resin composition of the present invention preferably contains an inorganic filler. The inorganic filler increases the heat capacity and suppresses heat transfer when heated to form an expansion heat insulating layer, and acts like an aggregate to improve the strength of the expansion heat insulating layer. The inorganic filler is not particularly limited, and examples thereof include alumina, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, metal oxides such as ferrite, calcium hydroxide, magnesium hydroxide, Metal hydroxides such as 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, calcium silicate, etc. Calcium salt, silica, diatomaceous earth, dawsonite, barium sulfate, talc, clay, mica, montmorillonite, bentonite, activated clay, sepiolite, imogolite, sericite, glass fiber, glass beads, silica balloon, aluminum nitride, boron nitride, silicon nitride , carbon black, graphite, carbon fiber, carbon balloon, 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 fibers, fly ash, and the like. An inorganic filler may be used individually by 1 type, and may use 2 or more types together.
Among these, at least one selected from metal oxides and metal carbonates is preferred.

The particle size of the inorganic filler is preferably 0.5-100 μm, more preferably 1-50 μm. By making it more than these lower limits, it prevents that a secondary aggregation arises, and dispersibility becomes favorable. Moreover, when it is set to the lower limit or more, the viscosity of the fire-resistant resin composition can be lowered, and the processability tends to be improved. Moreover, by making it below the upper limit, the surface properties and mechanical properties of the thermally expandable sheet formed from the fire-resistant resin composition are improved.
The particle size of the inorganic filler is obtained by observing a SEM (scanning electron microscope image) to determine the particle size distribution. The particle size is determined as the average particle size.

The content of the inorganic filler is preferably 10 to 200 parts by mass, more preferably 15 to 150 parts by mass, based on 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 amount is 200 parts by mass or less, workability is improved, and good mechanical properties are easily maintained.

(Plasticizer)
The fire resistant resin composition of the present invention may contain a plasticizer. By containing a plasticizer, the flexibility of the thermally expandable sheet or the like formed from the fire-resistant resin composition can be increased, and workability can be easily improved. A plasticizer is suitable when a thermoplastic resin is used as the resin described above, and is particularly preferably used when a polyvinyl chloride resin is used.
As the plasticizer, a liquid component that becomes liquid at normal temperature (23° C.) and normal pressure (1 atm) is generally used.

Specific examples of plasticizers include di-2-ethylhexyl phthalate (DOP), di-n-octyl phthalate, diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), diundecyl phthalate (DUP), or those having 10 to 10 carbon atoms. Phthalic acid ester plasticizers such as phthalic acid esters of higher alcohols or mixed alcohols of about 13, di-2-ethylhexyl adipate (DOA), diisobutyl adipate (DIBA), dibutyl adipate (DBA), di-n-octyl adipate, Aliphatic ester plasticizers such as di-n-decyl adipate, diisodecyl adipate, di-2-ethylhexyl azelate, dibutyl sebacate, di-2-ethylhexyl sebacate, tri-2-ethylhexyl trimellitate (TOTM), Trimellitate plasticizers such as tri-n-octyl trimellitate, tridecyl trimellitate, triisodecyl trimellitate, di-n-octyl-n-decyl trimellitate, 2,3,3' , 4′-biphenyltetracarboxylic acid tetraalkyl ester plasticizers such as tetraheptyl ester of biphenyltetracarboxylic acid, polyester polymer plasticizers, epoxidized soybean oil, epoxidized linseed oil, epoxidized cottonseed oil, liquid epoxy resins, etc. Epoxy-based plasticizers, chlorinated paraffins, and chlorinated fatty acid esters such as pentachlorinated stearic acid alkyl esters and the like can be mentioned.
These plasticizers may be used singly or in combination of two or more.
Among the above plasticizers, phthalic acid-based plasticizers are preferred from the viewpoint of flame retardancy and economy. A phthalate plasticizer may be used alone, or may be used in combination with a phosphate ester plasticizer.

The content of the plasticizer is preferably 30 to 130 parts by mass, more preferably 40 to 120 parts by mass, even more preferably 50 to 100 parts by mass, based on 100 parts by mass of the resin. When the content of the plasticizer is at least these lower limits, the flexibility of the sheet formed from the fire-resistant resin composition can be increased, and the workability of the sheet can be improved. , it is possible to prevent the sheet from becoming too soft.

The fire-resistant resin composition of the present invention may contain other components than those mentioned above. Other ingredients include antioxidants such as phenolic, amine, and sulfur antioxidants, metal damage inhibitors, antistatic agents, stabilizers, cross-linking agents, lubricants, softeners, pigments, etc., as long as they do not impair their physical properties. and various additives.

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

Although the thickness of the thermally expandable sheet is not particularly limited, it is preferably 0.2 to 10 mm, more preferably 0.5 to 3.0 mm, from the viewpoint of fire resistance and handleability.

(Method for producing thermally expandable 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, and other optional additives are kneaded by a kneader such as a kneading roll to obtain a fire-resistant resin composition.
Next, when the resin is a thermoplastic resin, rubber, elastomer, or a combination thereof, the obtained fire-resistant resin composition is formed into a sheet by a known molding method such as press molding, calender molding, or extrusion molding. A thermally expandable sheet is obtained by molding into
When the resin contains a thermosetting resin, it is preferable to heat and press the obtained fire-resistant resin composition, for example, by press molding to obtain a thermally expandable sheet by heat-curing while forming a sheet.

(Laminated sheet)
The thermally expandable sheet of the present invention may be laminated with another sheet member or an adhesive layer to form a laminated sheet. A laminated sheet includes, for example, a substrate and a thermally expandable sheet laminated on one side or both sides of the substrate. Substrates are typically woven or non-woven. Fibers used for woven fabrics or non-woven fabrics are not particularly limited, but nonflammable or quasi-flammable materials are preferred, such as glass fibers, ceramic fibers, cellulose fibers, polyester fibers, carbon fibers, graphite fibers, thermosetting A flexible resin fiber or the like is preferable.
The laminated sheet can be obtained, for example, by molding a fire-resistant resin composition on a base material into a sheet, and heat-curing the fire-resistant resin composition as necessary.

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

The fire-resistant resin composition of the present invention, the thermally expandable sheet and the laminate sheet made of the fire-resistant resin composition can each be used as a fire-resistant material. Specifically, these can be used for various buildings such as single-family houses, collective housing, high-rise housing, high-rise buildings, commercial facilities, and public facilities, various vehicles such as automobiles and trains, ships, and aircraft. , Among these, it is preferably used for buildings. As a building, specifically, it can be used for walls, beams, pillars, floors, bricks, roofs, plate materials, windows, shoji, doors, doors, sliding doors, transoms, wiring, piping, etc. It is not limited to these. Since the fire-resistant resin composition of the present invention is excellent in long-term fire resistance, it is particularly preferably used for specific fire prevention equipment, walls, beams, pillars, floors, and the like.

EXAMPLES The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to these.

[Evaluation method]
The decomposition temperature of the flame retardant and the expansion start temperature of the thermally expandable graphite were measured as follows.
(Decomposition temperature of flame retardant)
Measurement was performed based on JIS 7120. 10 mg of the flame retardant was collected as a sample, and a differential thermal-thermogravimetric simultaneous measurement device (manufactured by Hitachi High-Tech Science Co., Ltd., "Differential thermal and thermogravimetric simultaneous measurement device STA7200") was used. The decomposition temperature was defined as the temperature at which the mass of the flame retardant decreased by 10% under the conditions of 10°C/min and a measurement temperature of 100 to 800°C.
(Expansion start temperature of thermally expandable graphite)
100 mg of thermally expandable graphite was taken as a sample, and a rheometer (manufactured by TA Instruments, "Discovery HR2") was used to raise the temperature at a temperature of 10 ° C./min, and the force in the normal direction was increased. was measured, and this temperature was taken as the expansion start temperature.

The thermally expandable sheets obtained in Examples and Comparative Examples were measured for expansion ratio and residue hardness. The residual hardness represents the hardness of the test piece after heating, and the higher the value, the more excellent the fire resistance.
(expansion ratio)
A test piece (length 100 mm, width 100 mm, thickness 1.6 mm) prepared from the thermally expandable sheets of the obtained examples and comparative examples was placed on the bottom of a stainless steel holder (101 mm square, height 80 mm). , was supplied to an electric furnace and heated at 600° C. for 30 minutes. After that, the height (highest part) width, length, and thickness of the test piece are measured, and ((thickness of the test piece after heating) / (thickness of the test piece before heating)) expands Magnification was calculated.
(residue hardness)
The test piece after heating whose expansion ratio was measured is supplied to a compression tester (manufactured by Kato Tech Co., Ltd., "Finger Filling Tester"), and compressed at a speed of 0.1 cm / sec with a 3-point indenter with a diameter of 1 mm, and the residue The maximum stress up to 10 mm compression from the upper surface was measured, and the compressive strength of the test piece after burning was measured.
(fire resistance)
A 50 mm calcium silicate plate manufactured by A&A Material Co., Ltd. was cut out in a refractory furnace to a size of 1180 mm x 1180 mm, and a joint having a width of 20 mm and a length of 200 mm was formed in the center of the plate. A thermally expandable sheet having a thickness of 1.6 mm and a size of 10 mm×200 mm was attached to the side of the joint with an iron needle using a staple gun. The iron needle was fixed at three points, the top, bottom, and center, to prepare a test piece. This specimen was subjected to a fire resistance test for 120 minutes by adjusting the temperature according to the standard heating curve of ISO834 and setting the furnace pressure to 20 Pa. The test specimens during the fire resistance test were observed, and ◯ was given when the residue of the expansive material attached to the test specimen did not collapse for 120 minutes, and X was given when it crumbled and penetrated the furnace.

(Examples 1 to 14, Comparative Example 1)
A resin, a flame retardant, a thermally expandable graphite, an inorganic filler, a plasticizer, and a dispersant are put into a roll and kneaded at 130° C. for 5 minutes to obtain a fire-resistant resin composition according to the formulation shown in Table 1 below. rice field. The resulting fire-resistant resin composition was press-molded at 130° C. for 3 minutes to obtain a thermally expandable sheet with a thickness of 1.6 mm. Each component used in each example and comparative example is as follows.
(Examples 15-16)
A liquid silicone rubber (“ELASTOSHIL M4600” manufactured by Asahi Kasei Wacker Silicone Co., Ltd.) was mixed with a curing agent at a ratio of 10:1 (mass ratio) and cured at 23° C. for 12 hours to obtain a resin. The above resin, flame retardant, thermally expandable graphite, inorganic filler, plasticizer and dispersant were blended in a cup according to the formulation shown in Table 1 below and stirred with a planetary stirrer. The obtained mixture was pressed at 23° C., molded into a sheet of 1.6 mm, and allowed to stand at 23° C. for 12 hours to obtain a thermally expandable sheet with a thickness of 1.6 mm.

(1) Resin / PVC: Polyvinyl chloride resin, manufactured by Shin-Etsu Chemical Co., Ltd., trade name "TK-1000", average degree of polymerization 1030
・ Silicone rubber: liquid silicone rubber, manufactured by Asahi Kasei Wacker Silicone Co., Ltd., trade name “ELASTOSIL M4600”
(2) Flame retardant/phosphazene compound: manufactured by Otsuka Chemical Co., Ltd., trade name “SPB-100” decomposition temperature 380°C
・ Organophosphorus flame retardant: Teijin, trade name “FCX-210” Decomposition temperature: 360°C
- Brominated bisphenol A flame retardant: manufactured by Teijin Limited, trade name "Fireguard 7000", decomposition temperature 451°C
- Brominated bisphenol A flame retardant: manufactured by Teijin Limited, trade name "Fireguard 7500" decomposition temperature 454°C
- Brominated bisphenol A flame retardant: manufactured by Teijin Limited, trade name "Fireguard 8500" decomposition temperature 458°C
- Ammonium polyphosphate: Clariant Japan Co., Ltd., product name "AP422" decomposition temperature 300 ° C.
(3) Thermally expandable graphite/thermally expandable graphite: trade name “CA-60N” manufactured by Air Water Co., Ltd. Expansion start temperature: 230°C
・ Thermally expandable graphite: manufactured by ADT, trade name “ADT501” expansion start temperature 150 ° C.
(4) Inorganic filler/calcium carbonate: manufactured by Shiraishi Calcium Co., Ltd., trade name “BF300”
・ Zinc oxide: manufactured by Sakai Chemical Industry Co., Ltd., trade name “Type 1 zinc oxide”
(5) Plasticizer/DOP: Di-2-ethylhexyl phthalate, DOP manufactured by J-Plus Co., Ltd.
(6) Dispersant/TCP: tricresyl phosphate, TCP manufactured by Daihachi Chemical Co., Ltd.

As shown in the above examples, the thermally expandable sheet made of the fire-resistant resin composition of the present invention has a difference of 100° C. or more between the decomposition temperature of the flame retardant and the expansion start temperature of the thermally expandable graphite. After heating at 600° C. for 120 minutes, the hardness of the residue was high, indicating excellent long-term fire resistance. On the other hand, in the thermally expandable sheet of the comparative example, since the difference between the decomposition temperature of the flame retardant and the expansion start temperature of the thermally expandable graphite is less than 100° C., the residue hardness value is low, and the long-term heat-expandable sheet can be used. It was found to be inferior in fire resistance.

Claims (9)

A fire resistant resin composition containing a resin, thermally expandable graphite, and a flame retardant, wherein the difference between the decomposition temperature of the flame retardant and the expansion start temperature of the thermally expandable graphite (decomposition temperature of flame retardant - thermal expansion The expansion start temperature of flexible graphite) is 100 ° C. or higher ,
A fire-resistant resin composition , wherein the flame retardant is one or more selected from the group consisting of phosphorus-based flame retardants and brominated flame retardants, and the phosphorus-based flame retardant is a phosphazene-based compound . 2. The fire resistant resin composition according to claim 1, wherein the content of said flame retardant is 0.05 to 1 in mass ratio with respect to the content of said thermally expandable graphite. 3. The fire resistant resin composition according to claim 1, further comprising an organic phosphorus compound other than the phosphazene compound . 4. The fire resistant resin composition according to claim 3 , wherein the organic phosphorus compound is a phosphate ester compound. 5. The fire resistant resin composition according to any one of claims 1 to 4 , further comprising an inorganic filler. 6. The fire-resistant resin composition according to claim 5 , containing 10 to 200 parts by mass of an inorganic filler with respect to 100 parts by mass of the resin. The fire-resistant resin composition according to any one of claims 1 to 6 , which contains 50 to 200 parts by mass of said thermally expandable graphite with respect to 100 parts by mass of said resin. The fire-resistant resin composition according to any one of claims 1 to 7 , wherein the resin is a polyvinyl chloride resin. A thermally expandable sheet comprising the fire-resistant resin composition according to any one of claims 1 to 8 .