JP2022121040A - Thermally-expandable composition and refractory material - Google Patents

Abstract

To provide a thermally-expandable composition that enables the production of a refractory material having fire resistance and high moldability.SOLUTION: A thermally-expandable composition contains one or more matrix components selected from the group consisting of elastomer components, and thermally-expandable graphite, the thermally-expandable composition having a gel fraction of 50-87%.SELECTED DRAWING: None

Description

The present invention relates to thermally expandable compositions and refractory materials.

In the construction field, fireproof materials are used for building materials such as fittings, columns, and wall materials for fire prevention. As the refractory material, a refractory material in which rubber, thermally expandable graphite, and the like are blended with resin 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.
Refractory materials containing thermally expandable graphite are provided, for example, in gaps between fittings such as doors and windows provided in openings of buildings and frames such as door frames and window frames surrounding these, and in the event of a fire The sheet expands in the thickness direction, closes the gap between the fittings and the frame material, and can prevent the spread of fire.

JP 2017-141463 A

However, rubber-containing refractory materials may become hard or brittle due to rubber tending to crystallize. Especially when used in cold climates, this tendency is conspicuous, and problems such as deterioration of workability due to hardening, or cracks on the surface are likely to occur, resulting in problems in handling. there were.
In view of the above problems, a method of adding a plasticizer with a low freezing point during production of the refractory material may be considered in order to inhibit the crystallization tendency of rubber and improve the brittleness of the refractory material. However, in that case, when the sheet is used as a fire-resistant material, the sheet becomes soft and expands to a high degree, while the residual hardness becomes brittle, resulting in a decrease in fire resistance.
Accordingly, an object of the present invention is to provide a thermally expandable composition that can form a refractory material having improved brittleness, excellent cold resistance, and excellent fire resistance due to high residual hardness. do.

As a result of intensive studies, the present inventors found that the above problems can be solved by adjusting the gel fraction to 50 to 87% in a thermally expandable composition composed of an elastomer component and thermally expandable graphite. The following invention has been completed. That is, the present invention provides the following [1] to [6].
[1] A thermally expandable composition containing at least one matrix component selected from the group consisting of elastomer components and thermally expandable graphite, wherein the thermally expandable composition has a gel fraction of 50 to 87%. A thermally expandable composition.
[2] The thermally expandable composition according to [1], containing 30% by mass or more of the thermally expandable graphite.
[3] The thermally expandable composition according to [1] or [2], wherein the matrix component contains at least one of a halogen atom and a structural unit derived from styrene or acrylonitrile.
[4] The thermally expandable composition according to any one of [1] to [3], wherein the thermally expandable graphite has an expansion initiation temperature of 150°C or higher.
[5] The thermally expandable composition according to any one of [1] to [4], which does not contain a phosphorus component.
[6] A refractory material comprising the thermally expandable composition according to [1] to [5].

ADVANTAGE OF THE INVENTION According to this invention, it has the outstanding cold resistance, and can provide the heat-expandable composition which can manufacture the fireproof material excellent also in fire resistance.

Hereinafter, the present invention will be described using embodiments.
[Thermal expandable composition]
The thermally expandable composition of the present invention is a thermally expandable composition containing at least one matrix component selected from the group consisting of elastomer components and thermally expandable graphite.

<Gel fraction>
The thermally expandable composition of the present invention has a gel fraction of 50-87%. If the gel fraction is less than 50%, the residual hardness of the refractory material becomes low, resulting in impaired fire resistance and low cold resistance. On the other hand, if the gel fraction exceeds 87%, the thermally expandable composition becomes too hard, the expansion of the refractory material does not proceed sufficiently, the residue becomes brittle, and the fire resistance is impaired. From these points of view, the gel fraction is preferably 55 to 85%, more preferably 60 to 82%, even more preferably 65 to 80%.
The method for adjusting the gel fraction in the present invention is not particularly limited as long as it can be adjusted within the above range, but specific examples include the use of a cross-linking agent, a cross-linking accelerator, and electron beam irradiation. Among these, the use of a cross-linking agent and a cross-linking accelerator is preferred.
The method for measuring the gel fraction is as described in Examples, and the gel fraction is measured using the insoluble matter of the organic solvent (xylene) as the gel content, as will be described later. Therefore, the gel content also includes organic solvent-insoluble components such as inorganic fillers and thermally expandable graphite contained in the thermally expandable composition.

The thermally expandable composition is preferably blended with a cross-linking agent. The cross-linking agent is not particularly limited as long as it can adjust the gel fraction of the thermally expandable composition to the above range. Specific examples include sulfur-based cross-linking agents, metal oxide-based cross-linking agents, peroxide-based cross-linking agents, resin-based cross-linking agents, amine-based cross-linking agents, and oxime-based cross-linking agents.
When using a cross-linking agent in the thermally expandable composition of the present invention, it is preferable to use a sulfur-based cross-linking agent from the viewpoint of facilitating adjustment of the gel fraction of the thermally expandable composition to a desired range. It is more preferable to use a sulfur-based cross-linking agent in combination with a physical cross-linking agent.
The sulfur-based cross-linking agent may be an inorganic cross-linking agent such as sulfur, insoluble sulfur, precipitated sulfur, sulfur chloride, sulfur monochloride, sulfur dichloride, or a sulfur-containing organic cross-linking agent. Examples of sulfur-containing organic cross-linking agents include morpholine disulfide, alkylphenol disulfide, N,N'-dithio-bis(hexahydro-2H-azepinone-2), thiuram polysulfide, 2-(4'-morpholino-dithio)benzothiazole and the like. be done. In addition, among these, from the viewpoint of crosslinkability, inorganic compounds are preferred, and sulfur is more preferred.

Examples of metal oxide cross-linking agents include zinc oxide and magnesium oxide. When using metal oxides in the present invention, it is preferred to use zinc oxide.
Any one of the crosslinking agents may be used alone, or two may be used in combination, from the viewpoint of facilitating adjustment of the gel fraction of the thermally expandable composition to a desired range. Therefore, it is preferable to use the two types in combination, and as described above, it is more preferable to use the metal oxide-based cross-linking agent and the sulfur-based cross-linking agent in combination.

Moreover, a so-called masterbatch may be used as the cross-linking agent. As the masterbatch, a resin obtained by mixing the above-mentioned cross-linking agent can be used, and it is preferable to use an inorganic sulfur-based cross-linking agent such as sulfur as a sulfur masterbatch.

The amount of the cross-linking agent when using the cross-linking agent in the thermally expandable composition of the present invention is not particularly limited, but is preferably 0.5 to 5% by mass, more preferably 1 to 3.5% by mass, and further It is preferably 1.5 to 3% by mass.
More specifically, for example, when a sulfur-based cross-linking agent and a metal oxide cross-linking agent are used in combination, the amount of the sulfur-based cross-linking agent is preferably 0.2 to 3% by mass, more preferably 0.3 to 2% by mass. % by mass, more preferably 0.6 to 1.5% by mass. Also, the amount of the metal oxide cross-linking agent is preferably 0.3 to 4% by mass, more preferably 0.5 to 3% by mass, and still more preferably 0.8 to 2.4% by mass.
The blending amount of the cross-linking agent is the amount excluding the components other than the cross-linking agent when blended together with components such as a resin other than the cross-linking agent such as a masterbatch.

It is also preferable that the thermally expandable composition contains a cross-linking accelerator in addition to the cross-linking agent. The cross-linking accelerator used in the thermally expandable composition of the present invention is not particularly limited, but examples thereof include thiazole compounds, sulfenamide compounds, thiuram compounds, dithiocarbamate compounds, guanidine compounds, and the like. be done. Among these, thiazole compounds are preferred, and bis(benzothiazol-2-ylthio)zinc is more preferred.
A crosslinking accelerator may be used individually by 1 type, and may use 2 or more types together.

The amount of the cross-linking accelerator when it is used in the thermally expandable composition of the present invention is not particularly limited, but is preferably 0.1 to 5% by mass, more preferably 0.2 to 3% by mass. , more preferably 0.3 to 2% by mass.

<Matrix component>
The thermally expandable composition of the present invention contains an elastomer component as a matrix component.

(elastomer component)
The elastomer component in the matrix component is not particularly limited, but isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), hydrogenated styrene-butadiene copolymer rubber (HSBR), chloroprene rubber (CR ), acrylonitrile-butadiene rubber (NBR), hydrogenated acrylonitrile-butadiene rubber (HNBR), ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), natural rubber, butyl rubber, chlorinated butyl rubber , chlorosulfonated polyethylene, acrylic rubber, epichlorohydrin rubber, polyvulcanized rubber, non-vulcanized rubber, silicone rubber, fluororubber, urethane rubber and the like.

The elastomer component preferably contains a component having at least one of structural units derived from halogen atoms or styrene or acrylonitrile. Although these elastomer components tend to have good fire resistance, they tend to have high crystallinity and low cold resistance.
From such a viewpoint, the elastomer component is preferably at least one selected from styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), and chloroprene rubber (CR), and styrene-butadiene rubber (SBR ), and at least one selected from chloroprene rubber (CR) is more preferable.

The matrix component may consist of a component having at least one of structural units derived from halogen atoms or styrene or acrylonitrile as described above, but may also contain other components. As another component, EPDM is preferable from the viewpoint of moldability.
In addition, from the viewpoint of fire resistance, the component having at least one of a halogen atom or a structural unit derived from styrene or acrylonitrile is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, based on the total amount of the matrix component. %, more preferably 70 to 100% by mass, and even more preferably 85 to 100% by mass.

In addition, from the viewpoint of improving fire resistance and cold resistance by increasing the dispersibility of thermally expandable graphite and inhibiting the crystallization tendency of the elastomer component, styrene-butadiene rubber (SBR) and chloroprene rubber (CR) It is also preferable to use together.
When styrene-butadiene rubber (SBR) and chloroprene rubber (CR) are used together, their content ratio (SBR/CR) is preferably 90/10 to 10/90 by mass, preferably 80/20. More preferably ~20/80.

The amount of bound styrene in the styrene-butadiene rubber (SBR) used in the present invention is not particularly limited, but from the viewpoint of improving the moldability of the refractory material, it is, for example, 10 to 60% by mass, preferably 15 to 55% by mass. %, more preferably 20 to 50% by mass. The amount of bound styrene can be measured by ¹ H-NMR.
In addition, the Mooney viscosity [ML (1+4) 100° C.] of the styrene-butadiene rubber is not particularly limited, but from the viewpoint of improving the moldability of the refractory material, it is, for example, 30 to 150, preferably 35 to 70, More preferably 40-60.

The Mooney viscosity [ML (1+4) 100° C.] of the chloroprene rubber (CR) is not particularly limited, but from the viewpoint of improving the moldability of the refractory material, it is, for example, 25 to 150, preferably 30 to 100, and more. Preferably it is 35-75.
In this specification, the Mooney viscosity is a value measured according to JIS K6300.

The content of the matrix component in the thermally expandable composition is preferably 65% by mass or less, more preferably 60% by mass or less, preferably 20% by mass or more, more preferably 25% by mass or more, and 35% by mass or more. More preferred. By setting the matrix component to the above upper limit or less, the thermally expandable composition can contain a certain amount or more of the crosslinking agent, the crosslinking accelerator, the thermally expandable graphite, and the inorganic filler. Moreover, by making it below the said lower limit, it is easy to improve moldability etc.

<Thermal expandable graphite>
Thermally expandable graphite expands when heated, and is produced by treating powders of natural flake graphite, pyrolytic graphite, Kish graphite, etc. with an inorganic acid and a strong oxidizing agent to form a graphite intercalation compound. It is a type of crystalline compound that maintains the layered structure of carbon. Examples of inorganic acids include concentrated sulfuric acid, nitric acid, and selenic acid. Examples of strong oxidizing agents include concentrated nitric acid, perchloric acid, perchlorates, permanganates, bichromates, and hydrogen peroxide.
The thermally expandable graphite obtained by acid treatment as described above may be further neutralized with a neutralizing agent such as ammonia, lower aliphatic amines, alkali metal compounds, alkaline earth metal compounds and the like. Examples of aliphatic lower amines include monomethylamine, dimethylamine, trimethylamine, ethylamine, propylamine, butylamine and the like. Examples of the alkali metal compounds and alkaline earth metal compounds include hydroxides, oxides, carbonates, sulfates, organic acid salts of potassium, sodium, calcium, barium, magnesium and the like.

The expansion start temperature of the thermally expandable graphite used in the present invention is preferably 150° C. or higher, more preferably 155° C. or higher, and even more preferably 160° C. or higher, from the viewpoint of preventing expansion except when fire occurs. Also, in the event of fire, the temperature is preferably 250° C. or lower, more preferably 240° C. or lower, and even more preferably 230° C. or lower, from the viewpoint of increasing the volume increase rate of the thermally expandable graphite and effectively exhibiting fire resistance.

The content of thermally expandable graphite in the thermally expandable composition may be, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, and still more preferably 35% by mass or more. % by mass or more, preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less. By setting the content of the thermally expandable graphite to the above content, it becomes easier to obtain an expansion suitable for preventing the passage of fire, and it becomes easier to make the residual hardness an appropriate size, resulting in an excellent refractory material. can get.

<Inorganic filler>
The thermally expandable composition of the present invention may contain inorganic fillers. The inorganic filler is an inorganic filler other than the thermally expandable graphite and the cross-linking agent described above. The inorganic filler increases the heat capacity and suppresses heat transfer when heated to form an expansion heat insulating layer, while inhibiting the crystallization tendency of the rubber component in the matrix component and improving the cold resistance of the refractory material. .

From the viewpoint of improving the cold resistance of the refractory material, the inorganic filler preferably contains an inorganic filler A having a specific gravity of 2.5 or more. By including the inorganic filler A, the amount of the matrix component per unit volume can be increased, thereby improving the brittleness of the refractory material and making it easier to improve the cold resistance. From this point of view, the specific gravity of the inorganic filler A is preferably 3 or more, more preferably 4 or more. For example, a metal carbonate or the like can be used as the inorganic filler A having a specific gravity of 2.5 or more. The inorganic filler A may be used singly or in combination.
The content of the inorganic filler A is preferably 50% by mass or more, more preferably 80% by mass or more, and still more preferably 100% by mass based on the total amount of the inorganic filler.

As the inorganic filler, it is preferable to use the above-described inorganic filler A having a specific gravity of 2.5 or more, but an inorganic filler having a specific gravity of less than 2.5 can also be used.
Inorganic fillers that can be used in the present invention are not particularly limited. , zinc carbonate, strontium carbonate, barium carbonate and other metal carbonates, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, hydrotalcite and other metal hydroxides, calcium sulfate, gypsum fiber, calcium silicate and other calcium salts , 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 fibers, carbon balloons, various metal powders, potassium titanate, magnesium sulfate, lead zirconate titanate, aluminum borate, molybdenum sulfide, silicon carbide, stainless steel fibers, zinc borate, various magnetic powders, slag fibers, Phosphate metal salts such as fly ash, sodium phosphate, potassium phosphate, magnesium phosphate and aluminum phosphate, metal phosphites such as sodium phosphite, potassium phosphite, magnesium phosphite and aluminum phosphite salts, ammonium polyphosphate, metal orthophosphate, metal metaphosphate, and metal tripolyphosphate. An inorganic filler may be used individually by 1 type, and may use 2 or more types together.

Among these, iron oxides, metal hydroxides, metal carbonates, and the like are also preferable as inorganic fillers from the viewpoint of fire resistance.
Moreover, the inorganic filler more preferably contains at least iron oxide. By containing iron oxide, the expansion ratio and the hardness of the residue after expansion are increased, making it easier to improve the fire resistance.
In addition, when iron oxide is contained, the content of iron oxide is preferably 3 to 30% by mass, more preferably 5 to 15% by mass, and 6 to 9% by mass, relative to the total amount of the fire-resistant resin composition. % is more preferred.

Further, it is particularly preferable to use both iron oxide and calcium carbonate as the inorganic filler.
When iron oxide and calcium carbonate are used in combination, the mass ratio (iron oxide/calcium carbonate) is preferably 10/90 to 90/10, more preferably 20/80 to 80/20, and still more preferably 30/70 to 70/30.

The content of the inorganic filler in the thermally expandable composition is preferably 3% by mass or more, more preferably 8% by mass or more, still more preferably 10% by mass or more, and preferably 50% by mass or less, It is more preferably 30% by mass or less, still more preferably 20% by mass or less.

<Other ingredients>
In addition to the above-described cross-linking agent, cross-linking accelerator, matrix component, heat-expandable graphite, and inorganic filler, the thermally expandable composition contains various organic compounds such as bromine-containing flame retardants, nitrogen-containing flame retardants, and phosphate ester compounds. Various additives such as flame retardants, colorants and antioxidants may also be included.

Bromine-containing flame retardants include, for example, hexabromobenzene, pentabromotoluene, hexabromobiphenyl, decabromobiphenyl, hexabromocyclodecane, decabromodiphenyl ether, octabromodiphenyl ether, hexabromodiphenyl ether, bis(pentabromophenoxy) ethane, ethylene-bis(tetrabromophthalimide), tetrabromobisphenol A and the like.

Nitrogen-containing flame retardants include, for example, melamine, butylmelamine, trimethylolmelamine, hexamethylolmelamine, hexamethoxymethylmelamine, melamine derivatives such as melamine phosphate, cyanuric acid, methylcyanurate, diethylcyanurate, trimethylcyanurate, Cyanuric acid derivatives such as triethyl cyanurate, isocyanuric acid, methyl isocyanurate, N,N'-diethyl isocyanurate, trismethyl isocyanurate, trisethyl isocyanurate, bis(2-carboxyethyl) isocyanurate, 1,3,5 -isocyanuric acid derivatives such as tris(2-carboxyethyl)isocyanurate and tris(2,3-epoxypropyl)isocyanurate, melamine cyanurate, melamine isocyanurate, ethylenediamine phosphate and the like.

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.
The organic flame retardants may be used singly or in combination of two or more. When using an organic flame retardant, the content of the organic flame retardant in the thermally expandable composition is, for example, 1 to 35% by mass, preferably 5 to 30% by mass, more preferably 10 to 25% by mass.

The thermally expandable composition of the present invention preferably does not substantially contain organic additives such as organic flame retardants and plasticizers. In this specification, an organic salt such as ethylenediamine phosphate, which is composed of an organic substance and an inorganic substance, is also defined as an organic additive. Also, the above-described cross-linking agents and cross-linking accelerators, which are organic substances, are organic additives, but the elastomer component and the resin component are not organic additives.
Since the thermally expandable composition does not substantially contain an organic additive, it is possible to prevent bleeding out due to the plasticizer and prevent contamination of peripheral members such as sashes that come into contact with the thermally expandable composition. can be done.
Here, "substantially free" means that the content of the organic additive in the thermally expandable composition is less than 3% by mass, preferably less than 1% by mass.

<Phosphorus component>
Preferably, the thermally expandable composition of the present invention does not contain a phosphorus component. By not containing a phosphorus component, the water resistance of the refractory material formed from the thermally expandable composition is improved. Therefore, even after being exposed to water for a long period of time, it is possible to ensure excellent expansion ratio, residue hardness, and shape retention after expansion. Here, the phosphorus component is a compound containing a phosphorus atom, and includes the above-described cross-linking agent, cross-linking accelerator, matrix component, thermally expandable graphite, inorganic filler, and, if necessary, an organic flame retardant, As additives such as coloring agents and antioxidants, it is preferable not to use compounds containing phosphorus atoms.

The expansion ratio of the thermally expandable composition of the present invention is preferably 20.5 to 70 times, more preferably 25 to 60 times, still more preferably 30 to 55 times, from the viewpoint of fire resistance.
The thermally expandable composition of the present invention preferably exhibits an expansion ratio within the above range even after being immersed in water at 60° C. for one week. If the expansion ratio is within the above range after being immersed in water for a long period of time, the water resistance is also good. The expansion ratio can be obtained by measuring the change in the thickness direction of the sheet-like thermally expandable composition before and after heating.

In addition, the thermally expandable composition of the present invention preferably has a residual hardness of 0.15 kgf/cm ² or more, more preferably 0.20 kgf/cm ² or more, still more preferably 0.27 kgf/cm 2 or more after thermal expansion. ² or more, more preferably 0.30 kgf/cm ² or more. The hardness of the residue is preferably 0.70 kgf/cm ² or less, more preferably 0.60 kgf/cm ² or less, from the viewpoint of maintaining a constant expansion ratio and easily ensuring fire resistance. It is preferably 0.55 kgf/cm ² or less.
The thermally expandable composition of the present invention preferably exhibits residual hardness within the above range even after being immersed in water at 60° C. for one week. If the swelling residue is within the above range after being immersed in water for a long period of time, the water resistance is also good. The residue hardness can be obtained by measuring the hardness of the expansion residue after the thermally expandable composition is heated and expanded.

Although the shape of the thermally expandable composition is not particularly limited, it is preferably molded into a predetermined shape such as a sheet. The thickness of the thermally expandable composition molded into a predetermined shape (also referred to as "refractory material") is not particularly limited, but from the viewpoint of fire resistance and handleability, it is preferably 0.2 to 10 mm, and 0.5 to 0.5 mm. 3.0 mm is more preferred.

As described above, the refractory material of the present invention has excellent cold resistance and is less likely to cause problems such as breakage during use and cracks on the surface. It can be used as a long product of 1 m or more.

The thermally expandable composition of the present invention can be produced, for example, as follows.
First, predetermined amounts of matrix components, thermally expandable graphite, inorganic filler resin, and additives such as organic flame retardants, colorants, and antioxidants that are blended as necessary are mixed with a kneading machine such as a kneading roll. to obtain a raw material mixture.
Next, the obtained raw material mixture is crosslinked to form the thermally expandable composition of the present invention. Crosslinking of the raw material mixture is preferably carried out by heating. Specifically, the raw material mixture is heated at, for example, 155 to 195° C., preferably 160 to 180° C., for 5 to 30 minutes, preferably 10 to 25 minutes. cross-link with A predetermined gel fraction can be obtained by heating in such a temperature range for a predetermined period of time.
Moreover, it is preferable to crosslink the raw material mixture while molding it into a desired shape. Specifically, it is preferable to crosslink while molding into a desired shape such as a sheet by a known molding method such as press molding, calendar molding, or extrusion molding. Moreover, after molding into a desired shape, the resin may be crosslinked by heating under the above heating conditions.

The thermally expandable composition of the present invention is used as a fireproof material in various fields. Refractory materials 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, and various vehicles such as ships and aircraft. When a fire breaks out in a building, a vehicle, or the like, the refractory material expands as it is heated, blocks the flow of air, and exhibits fire-extinguishing properties.
Refractory materials are used by being attached to members constituting the above buildings, vehicles, ships, aircraft, and the like. For example, in buildings, it can be attached to fittings such as windows, shojis, doors, doors, sliding doors, pillars, walls such as steel-framed concrete, floors, roofs, etc., to reduce or prevent the intrusion of fire and smoke. The refractory material can also be used as part of the compartment penetration treatment material that closes the penetration of the compartment penetration structure. Among these, it is preferable to use it for fittings.

The refractory material may be used as a single refractory material, or may be used with other members attached as appropriate. For example, the refractory material may be laminated with members other than the refractory material, and a base material may be provided on at least one surface of the refractory material. The substrate may be a combustible material layer, a quasi-noncombustible material layer, or a noncombustible material layer. Although the thickness of the base material is not particularly limited, it is, for example, 5 μm to 1 mm. Materials used for the combustible material layer include, for example, one or more of cloth materials, paper materials, wood materials, resin films, and the like. When the substrate is a quasi-noncombustible material layer or a noncombustible material layer, examples of the material used include metals, inorganic materials, etc. More specifically, glass fiber, ceramic fiber, carbon fiber, A woven fabric or non-woven fabric made of graphite fiber may be used. Composite materials of these fibers and metals may also be used, and for example, aluminum glass cloth is preferable.
Moreover, an adhesive layer may be laminated on the refractory material. The use of the pressure-sensitive adhesive layer makes it possible to easily adhere the refractory material to other members. The pressure-sensitive adhesive layer may be provided on the substrate, or may be formed directly on the surface of the refractory material. Moreover, you may use the double-sided adhesive tape which equips both surfaces of a base material with an adhesive layer. In this case, one pressure-sensitive adhesive layer is attached to the refractory material, and the other pressure-sensitive adhesive layer is preferably used to attach another member.

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 and measurement method]
(1) Expansion ratio A test piece (length 100 mm, width 100 mm, thickness 1.5 mm) prepared from the thermally expandable composition obtained in each example and comparative example was placed in 500 mL of pure water at 60 ° C. in a closed container. After one week of immersion in water, the samples were removed. A test piece prepared by evaporating and drying the sample at 60 ° C. for 96 hours is placed on the bottom of a stainless steel holder (101 mm square, height 80 mm), supplied to an electric furnace, and heated at 600 ° C. for 30 minutes. did. After that, the width, length, and thickness of the thickest part 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.
(2) Residual hardness The heated test piece whose expansion ratio was measured was supplied to a compression tester ("Finger Filling Tester" manufactured by Kato Tech Co., Ltd.), and a 3-point indenter with a diameter of 1 mm was used to obtain a hardness of 0.1 cm / sec. Compressed at a high speed, the maximum stress from the upper surface of the residue to 10 mm compression was measured, and the compressive strength (kgf/cm ² ) of the test piece after burning was measured.

(3) Gel fraction The gel fraction was measured and calculated by the methods described in (a) to (e) below.
(a) About 50 g of the thermally expandable composition was weighed, and the mass obtained by this weighing was defined as W1.
(b) A bottomed cylindrical container made of #100 mesh of SUS304 was weighed, and the weight obtained by this weighing was defined as W2.
(c) Place the weighed thermally expandable composition in a cylindrical container, immerse the composition together with the cylindrical container in 100 mL of toluene, and allow to stand at room temperature (23° C.) for 7 days to remove the sol content of the rubber component. was filtered.
(d) The residue of the thermally expandable composition soaked and filtered by the method of (c) above is lifted from the toluene together with the cylindrical container and filtered, and then the residue in the cylindrical container is It was dried for 24 hours and then dried at 80° C. for 24 hours.
(e) Based on W1 to W3 obtained in (a) to (d) above, the gel fraction was calculated using the following formula.
Gel fraction (%) = ((W3-W2)/W1) x 100

(4) Cold resistance (brittleness)
The above-mentioned test pieces obtained in each example and comparative example were fixed and sandwiched between parallel plates spaced at intervals of 60 mm, and allowed to stand at 0° C. for 5 minutes. After the standing, the interval between the parallel plates was quickly narrowed to 25 mm and the test piece was bent, and the presence or absence of change in the test piece due to the bending at that time was visually confirmed. The evaluation criteria for changes in test pieces are as follows.
〇: No change △: Cracks occurred on the surface ×: Broken

(5) Expansion start temperature In a rheometer (“Discovery HR-2”, manufactured by TA Instruments), place 0.5 g of a thermally expandable graphite sample on the sample stage and wrap it with aluminum foil so that the powder does not fall. . A 25 mmφ cone plate was grounded until the load reached 0 [N]. From this state, the sample was heated from a set temperature of 50° C. with a Peltier heater at a constant heating rate (10° C./min), and the expansion start temperature was taken when the load reached 0.1 N.

(Examples 1-22, Comparative Examples 1-2)
The matrix component, thermally expandable graphite, and inorganic filler were put into a kneader mixer and kneaded at 110° C. for 5 minutes according to the formulations shown in Tables 1 to 3 below to obtain a mixed composition. The resulting mixed composition was press-molded with a hot press to form a sheet while cross-linking the mixed composition to obtain a refractory material (thermally expandable composition) having a thickness of 1.5 mm. Each component used in each example and comparative example is as follows.

(1) Matrix component <chloroprene rubber: CR>
・"B-30" manufactured by CR Tosoh Corporation
Mooney viscosity [ML (1 + 4) 100 ° C.]: 45 to 53

<Styrene-butadiene rubber: SBR>
・"JSR1500" manufactured by SBR JSR Corporation
Bound styrene content: 23.5% by mass, Mooney viscosity [ML (1 + 4) 100°C]: 52
・SBR2 “JSR0202” manufactured by JSR Corporation
Bound styrene content: 46% by mass, Mooney viscosity [ML (1+4) 100°C]: 45
・SBR3 "JSR0122" manufactured by JSR Corporation
Bound styrene content: 37% by mass, Mooney viscosity [ML (1+4) 100°C]: 52

<Acrylonitrile-butadiene rubber: NBR>
・"N220S" manufactured by NBR JSR Corporation

(2) Inorganic filler/iron oxide: Titan Kogyo Co., Ltd. “BL-100”, specific gravity 5.1
・ Calcium carbonate: Bihoku Funka Kogyo Co., Ltd. “Whiten BF-300”, specific gravity 2.93

(3) Thermally expandable graphite/thermally expandable graphite 1 “CA-60N” manufactured by Air Water, expansion start temperature 220 ° C.
・ Thermally expandable graphite 2 “EXP-50S150” manufactured by Fuji Graphite Industry Co., Ltd., expansion start temperature 160 ° C.
(4) Cross-linking agent / sulfur-based cross-linking agent “Sanmix S-80N” manufactured by Sanshin Chemical Industry Co., Ltd., sulfur content 80% by mass, sulfur masterbatch / zinc oxide Sakai Chemical Industry Co., Ltd. “Zinc oxide type 2”
(5) Cross-linking accelerator, bis (benzothiazol-2-ylthio) zinc Sanshin Chemical Industry Co., Ltd. "Sancellar MZ"

As shown in the examples, a refractory material formed from a thermally expandable composition containing thermally expandable graphite and having a gel fraction within the range of 50 to 87% has an expansion ratio and a residue hardness value of Since it is high, it was found that the fire resistance is good and the cold resistance is also excellent.
On the other hand, as shown in Comparative Examples, a refractory material formed from a thermally expandable composition having a gel fraction outside the range of 50 to 87%, even if it contains thermally expandable graphite, has good fire resistance and cold resistance. one of which was damaged.

Claims (6)

A thermally expandable composition containing one or more matrix components selected from the group consisting of elastomer components and thermally expandable graphite,
A thermally expandable composition having a gel fraction of 50 to 87%. The thermally expandable composition according to claim 1, containing 30% by mass or more of the thermally expandable graphite. 3. The thermally expandable composition according to claim 1 or 2, wherein the matrix component contains a component having at least one of halogen atoms and structural units derived from styrene or acrylonitrile. The thermally expandable composition according to any one of claims 1 to 3, wherein the thermally expandable graphite has an expansion initiation temperature of 150°C or higher. The thermally expandable composition according to any one of claims 1 to 4, which does not contain a phosphorus component. A fire-resistant material comprising the thermally expandable composition according to any one of claims 1 to 5.