JP7057202B2 - Refractory sheet and its manufacturing method - Google Patents

Description

The present invention relates to a refractory sheet used for buildings, vehicles, etc., and a method for manufacturing the same.

Refractory sheets are widely used to ensure the fire resistance of structures such as buildings and various vehicles. As a refractory sheet, a composition containing a resin component such as an epoxy resin and a heat-expandable graphite blended in the resin component is known to be molded into a sheet shape. Such a refractory sheet secures fire resistance by expanding the heat-expandable graphite to form a heat insulating layer when heated.

The refractory sheet is generally blended with an inorganic filler in order to secure a certain mechanical strength after thermal expansion and increase the heat capacity (see, for example, Patent Document 1). However, the refractory sheet tends to have a reduced flexibility due to the inclusion of the inorganic filler, and in particular, the flexibility becomes poor when a large amount of the inorganic filler is blended in order to secure high strength. A refractory sheet with poor flexibility becomes fragile when rolled, making it difficult to roll a long product into a roll, or reducing workability.

Conventionally, a resin containing 100 parts by weight of an epoxy resin, 25 to 200 parts by weight of a phosphorus compound, 10 to 150 parts by weight of heat-expandable graphite, 10 to 200 parts by weight of an inorganic filler, and 2 to 50 parts by weight of a foaming agent. Epoxy resin foams obtained by foaming a composition are known (see, for example, Patent Document 2). This epoxy resin foam is imparted with flame retardancy and fire resistance by a phosphorus compound, heat-expandable graphite that expands when heated, and the like, and because it is a foam, flexibility is also ensured.

Japanese Unexamined Patent Publication No. 2000-143941 Japanese Patent Application Laid-Open No. 2003-64209

However, since the foam of Patent Document 2 is foamed by a foaming agent and has a high porosity, it is difficult to obtain excellent fire resistance because the expansion ratio after heating cannot be increased.
Further, in the manufacturing process of the refractory sheet, it is general that the resin composition is transferred while being pressurized inside the pipe, or the inside of the molding machine is transferred by a screw. However, since the refractory sheet has a high specific gravity due to the addition of the inorganic filler, pressure loss is likely to occur inside the piping or the molding machine, and the productivity is lowered.

Therefore, it is an object of the present invention to provide a fireproof sheet capable of improving productivity by reducing pressure loss inside a pipe or a molding machine at the time of manufacturing while improving fireproof performance and flexibility.

As a result of diligent studies, the present inventors have made a plurality of bubbles contained in the refractory sheet containing the matrix resin, the heat-expandable graphite, and the inorganic filler, and determined the average diameter and the bubble area ratio of the bubbles. We have found that the above problems can be solved by setting the scope, and have completed the following invention. The gist of the present invention is as shown in the following [1] to [9].

[1] A refractory sheet containing a matrix resin, a heat-expandable graphite, and an inorganic filler, and containing a plurality of bubbles inside.
A refractory sheet having an average diameter of 90 μm or more and a bubble area ratio of 3 to 25% in a cross section.
[2] The refractory sheet according to the above [1], wherein the heat-expandable graphite is 10 to 300 parts by mass and the inorganic filler is 10 to 300 parts by mass with respect to 100 parts by mass of the matrix resin.
[3] The refractory sheet according to the above [1] or [2], wherein the matrix resin is a thermosetting resin.
[4] The refractory sheet according to the above [3], wherein the thermosetting resin is an epoxy resin.
[5] The refractory sheet according to the above [4], wherein the heat-expandable graphite is 50 to 200 parts by mass and the inorganic filler is 100 to 300 parts by mass with respect to 100 parts by mass of the epoxy resin.
[6] The fireproof sheet according to any one of the above [1] to [5], which contains a dispersant.
[7] The fireproof sheet according to any one of the above [1] to [6], which has a total length of 2 m or more.
[8] The refractory sheet according to the above [7], which is rolled into a roll.
[9] A fitting provided with the fireproof sheet according to any one of the above [1] to [8].

INDUSTRIAL APPLICABILITY The present invention provides a fire-resistant sheet capable of improving productivity by reducing pressure loss inside a pipe or a molding machine during manufacturing while improving fire resistance and flexibility.

Hereinafter, the present invention will be described in more detail.
<Fireproof sheet>
The refractory sheet of the present invention is a refractory sheet containing a matrix resin, a heat-expandable graphite, and an inorganic filler, and containing a plurality of bubbles inside.

[Bubble]
In the refractory sheet of the present invention, the average diameter of the plurality of bubbles is 90 μm or more, and the bubble area ratio in the cross section is 3 to 25%. The refractory sheet of the present invention has good fire resistance and flexibility when the average diameter of bubbles and the ratio of bubble area are within the above ranges. Further, in the manufacturing process of the fireproof sheet, the apparent specific gravity is lowered by mixing the bubbles so as to have the above-mentioned average diameter and bubble area ratio, and the pressure loss when transferring the inside of the piping, the molding machine, etc. is reduced. , Productivity tends to be good.

On the other hand, if the average diameter of the bubbles is less than 90 μm, the flexibility cannot be sufficiently improved when the bubble area ratio is as low as 3 to 25%. Further, when the average diameter is less than 90 μm, even if a predetermined amount of air bubbles is mixed to reduce the apparent specific gravity, the pressure loss when transferring the inside of the pipe, the molding machine, or the like tends to be large, and the productivity is lowered.
The average diameter of the bubbles is preferably 150 μm or more, more preferably 200 μm or more, still more preferably 220 μm or more, from the viewpoint of further improving flexibility and reducing pressure loss. The average diameter of the bubbles is preferably 500 μm or less. When the average diameter is 500 μm or less, the mechanical strength and moldability of the refractory sheet are good. From these viewpoints, the average diameter is more preferably 450 μm or less, still more preferably 400 μm or less.

Further, when the bubble area ratio is less than 3%, it is difficult to improve the flexibility and productivity of the refractory sheet even if the average diameter of the bubbles is increased. On the other hand, if the bubble area ratio is larger than 25%, it becomes difficult to expand the refractory sheet at a sufficient expansion ratio even when heated, and the fire resistance performance deteriorates.
From the viewpoint of fire resistance, the bubble area ratio is preferably 22% or less, preferably 20% or less. Further, from the viewpoint of flexibility and productivity, the bubble area ratio is preferably 5% or more, more preferably 8% or more, still more preferably 10% or more.

The average diameter of bubbles is obtained by measuring the diameters of 20 bubbles in the cross section of the refractory sheet and calculating the average value thereof. The bubble area ratio is obtained by calculating (total area of bubbles / cross-sectional area of the sheet) × 100 in the cross section of the refractory sheet. Details of the method for measuring the average diameter of bubbles and the ratio of bubble area are as described in Examples described later.
In the refractory sheet of the present invention, a plurality of bubbles are dispersed inside the matrix resin. The bubbles are not particularly limited, but may be formed by air mixed from the outside of the refractory sheet as described later.

[Matrix resin]
Examples of the resin component constituting the matrix resin include a thermoplastic resin, a rubber substance, a thermosetting resin, and a combination of two or more selected from these. Among these, it is preferable to use a thermosetting resin.

(Thermoplastic resin)
Examples of the thermoplastic resin include polyolefin resins such as polypropylene resin, polyethylene resin, poly (1-) butene resin, and polypentene resin, polystyrene resin, acrylonitrile-butadiene-styrene (ABS) resin, and ethylene vinyl acetate copolymer (EVA). ), Polyphenylene ether resin, (meth) acrylic resin, polyamide resin, polyvinyl chloride resin (PVC), novolak resin, polyurethane resin, polyisobutylene and other synthetic resins.
Among these, polyvinyl chloride resin and ethylene vinyl acetate copolymer are preferable.

Examples of the polyvinyl chloride resin include a polyvinyl chloride homopolymer, a copolymer of a vinyl chloride monomer and a monomer having an unsaturated bond commutable with the vinyl chloride monomer, and a polymer other than vinyl chloride. Examples thereof include a graft copolymer obtained by graft-copolymerizing vinyl, and these may be used alone or in combination of two or more. Further, the chlorinated polyvinyl chloride resin, which is a chlorinated product of the polyvinyl chloride resin, is also included in the polyvinyl chloride resin.
The ethylene-vinyl acetate copolymer is not particularly limited, but a vinyl acetate content measured in accordance with JIS K7192: 1999 is 5 to 48% by mass, preferably 10 to 40% by mass.

(Rubber substance)
Rubber substances 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 (EPM), ethylene-propylene- Examples thereof include rubber substances such as diene rubber (EPDM), chlorosulfonated polyethylene, acrylic rubber, epichlorohydrin rubber, silicon rubber, fluororubber, and urethane rubber. The rubber substance may be vulcanized rubber or non-vulcanized rubber. Among these, EPDM is preferable.

(Thermosetting resin)
Examples of the thermosetting resin include synthetic resins such as polyurethane resin, phenol resin, epoxy resin, urea resin, melamine resin, unsaturated polyester resin, and polyimide. The thermosetting resin can be obtained by reacting the main agent alone or by reacting the main agent with the curing agent. More specifically, the polyurethane resin can be obtained by reacting, for example, a polyol compound as a main agent with a curing agent such as a polyisocyanate compound as a curing agent. Further, the epoxy resin is generally obtained by reacting an epoxy compound as a main agent with a curing agent, but the epoxy compound alone may be reacted.
Among these thermosetting resins, epoxy resin is preferable. By using an epoxy resin, the sheet does not become brittle even when filled with a large amount of filler, and it is possible to maintain toughness.
In the present specification, unless otherwise specified, the total amount of the components that react to form a thermosetting resin, for example, the total amount of the main agent and the curing agent is defined as the content of the thermosetting resin. Further, in the case of a thermosetting resin, the resin component in the fire-resistant resin composition described later means a component that reacts to become a thermosetting resin, for example, a main agent and a curing agent.

The above-mentioned resin components may be used alone or in combination of two or more. When two or more kinds of resin components are used in combination, two or more kinds of resin components of the same type (for example, a thermoplastic resin and a thermoplastic resin) may be used in combination, or different kinds of resin components (for example, a thermoplastic resin and heat) may be used in combination. Curable resin) may be used in combination of two or more.

(Epoxy resin)
The epoxy resin used in the present invention is not particularly limited, but is obtained, for example, by reacting an epoxy compound with a curing agent, but may be obtained by reacting an epoxy compound alone. The epoxy compound is a compound having an epoxy group, and specific examples thereof include a glycidyl ether type and a glycidyl ester type. The glycisyl ether type may be bifunctional or may be trifunctional or higher. The same applies to the glycidyl ester type. The epoxy compound may contain a monofunctional one in order to adjust the degree of cross-linking or the like. Among these, the bifunctional glycidyl ether type is preferable.

Examples of the bifunctional glycidyl ether type epoxy compound include alkylene glycol type such as polyethylene glycol type and polypropylene glycol type, neopentyl glycol type, 1,6-hexanediol type, and aliphatic such as hydrogenated bisphenol A type. Epoxy compounds are exemplified. Further, aromatic epoxy compounds containing an aromatic ring such as bisphenol A type, bisphenol F type, bisphenol AD type, ethylene oxide-bisphenol A type, and propylene oxide-bisphenol A type can be mentioned. Among these, aromatic epoxy compounds such as bisphenol A type and bisphenol F type are preferable.

Examples of the glycidyl ester type epoxy compound include epoxy compounds such as hexahydrophthalic anhydride type, tetrahydrophthalic anhydride type, dimer acid type, and p-oxybenzoic acid type.
Examples of the trifunctional or higher functional glycidyl ether type epoxy compound include phenol novolac type, orthocresol novolak type, DPP novolak type, dicyclopentadiene / phenol type and the like.
These epoxy compounds may be used alone or in combination of two or more.

As the curing agent, a double addition type or a catalytic type is used. Examples of the heavy addition type curing agent include polyamine-based curing agents, acid anhydride-based curing agents, polyphenol-based curing agents, and polymercaptans. Examples of the catalyst-type curing agent include tertiary amines, imidazoles, and Lewis acid complexes.
The method for curing the epoxy resin is not particularly limited, and can be performed by a known method. For example, the epoxy resin can be cured by mixing a curing agent with an epoxy compound and heating the resin.

Further, the epoxy resin may be one to which flexibility is imparted. The following methods are used to impart flexibility.
(1) Increase the molecular weight between the cross-linking points.
(2) Reduce the crosslink density.
(3) Introduce a soft molecular structure.
(4) Add a plasticizer.
(5) Introduce a mutual intrusion network (IPM) structure.
(6) The rubber-like particles are dispersed and introduced.
(7) Introduce microvoids.

The above (1) is a method of reacting at least one of an epoxy compound and a curing agent with a long molecular chain in advance to increase the distance between cross-linking points and develop flexibility. .. For example, a polyether diamine such as polypropylene diamine may be used as the curing agent.
(2) is a method of reducing the crosslink density in a certain region and developing flexibility by reacting at least one of an epoxy compound and a curing agent with a small number of functional groups. For example, a bifunctional amine may be used as the curing agent, or a monofunctional epoxy compound may be used as at least a part of the epoxy compound.
(3) is a method for developing flexibility by using at least one of an epoxy compound and a curing agent having a soft molecular structure. For example, it is preferable to use a complex cyclic diamine as a curing agent, or an alkylene glycol glucidyl ether or the like as an epoxy compound.

(4) is a method of adding a plasticizer to a refractory sheet as a non-reactive diluent. (5) is a method of exhibiting flexibility with an interpenetrating network (IPN) structure in which a resin having another soft structure is introduced into the crosslinked structure of the epoxy resin. (6) is a method of blending and dispersing liquid or granular rubber particles in an epoxy resin matrix. (7) is a method for exhibiting flexibility by introducing microvoids having a size of 1 μm or less into an epoxy resin matrix.

(Plasticizer)
The refractory sheet may contain a plasticizer. By containing a plasticizer in the refractory sheet, it becomes easy to increase the flexibility and workability of the refractory sheet. In particular, when the thermoplastic resin is a polyvinyl chloride resin, the refractory sheet preferably contains a plasticizer. Further, even when the thermosetting resin such as epoxy resin is used as described above, the fireproof sheet can impart flexibility to the thermosetting resin such as epoxy resin by containing a plasticizer. become.

Examples of the plasticizer include phthalate-based plasticizers such as di-2-ethylhexylphthalate (DOP), dibutylphthalate (DBP), diheptylphthalate (DHP), and diisodecylphthalate (DIDP), and di-2-ethylhexyl adipate (DOA). ), Diisobutyl adipate (DIBA), adipyl acid ester plasticizer such as dibutyl adipate (DBA), epoxidized ester plasticizer such as epoxidized soybean oil, tri-2-ethylhexyl trimertate (TOTM), triisononyl Examples thereof include trimellitic acid ester-based plasticizers such as trimellitate (TINTM), tars, and petroleum resins. The plasticizer may be used alone or in combination of two or more.

The content of the plasticizer in the refractory sheet is preferably 10 to 150 parts by mass, more preferably 20 to 100 parts by mass, and further preferably 30 to 80 parts by mass with respect to 100 parts by mass of the resin component. By setting the amount of the plasticizer used within these ranges, it becomes easy to impart flexibility to the refractory sheet while improving workability.
When the refractory sheet contains a plasticizer, the matrix resin in the present specification comprises the above resin component and a plasticizer. That is, the matrix resin is composed of the above resin component, or the resin component and the plasticizer, and the mass part of the matrix resin includes the mass part of the plasticizer in addition to the resin component.

The content of the matrix resin in the refractory sheet is preferably 12 to 60% by mass based on the total amount of the refractory sheet. By using a matrix resin having a lower limit or more, the shape retention of the refractory sheet is improved. Further, by setting the value to the upper limit or less, it becomes possible to add a certain amount or more of the heat-expandable graphite and the inorganic filler. From these viewpoints, the content of the matrix resin is preferably 15 to 50% by mass, more preferably 18 to 32% by mass.

[Thermal expandable graphite]
The refractory sheet of the present invention contains heat-expandable graphite. Thermally expandable graphite expands when heated, and is obtained by treating powders such as natural scaly graphite, thermally decomposed graphite, and kiss graphite with an inorganic acid and a strong oxidizing agent to form a graphite intercalation compound. It is a kind of crystalline compound that maintains the layered structure of carbon. Examples of the inorganic acid include concentrated sulfuric acid, nitric acid and selenic acid. Examples of the strong oxidizing agent include concentrated nitric acid, perchloric acid, perchlorate, permanganate, dichromate, hydrogen peroxide and the like.
Further, the heat-expandable graphite obtained by acid treatment 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. Examples of the aliphatic lower amine include monomethylamine, dimethylamine, trimethylamine, ethylamine, propylamine, butylamine and the like. Examples of the alkali metal compound and the alkaline earth metal compound include hydroxides such as potassium, sodium, calcium, barium and magnesium, oxides, carbonates, sulfates and organic acid salts.

[Inorganic filler]
The refractory sheet of the present invention further contains an inorganic filler in addition to the heat-expandable graphite. The inorganic filler serves as an aggregate to improve the mechanical strength of the refractory sheet (ie, expansion residue) after heating and expansion, and to increase the heat capacity of the refractory sheet.
Specific examples of the inorganic filler are not particularly limited, but for example, alumina, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, ferrite and other metal oxides, calcium hydroxide, and the like. Metal hydroxides such as magnesium hydroxide, aluminum hydroxide, hydrotalcite, basic magnesium carbonate, calcium carbonate, magnesium carbonate, zinc carbonate, strontium carbonate, metal carbonates such as barium carbonate, gypsum fiber, calcium silicate, Silica, diatomaceous soil, dosonite, barium sulfate, talc, clay, mica, montmorillonite, bentonite, active white clay, sepiolite, imogolite, sericite, glass fiber, glass beads, silica-based balun, aluminum nitride, boron nitride, silicon nitride, carbon black. , Graphite, carbon fiber, carbon balun, charcoal powder, various metal powders, potassium titanate, magnesium sulfate, lead zirconate titanate, zinc stearate, calcium stearate, aluminum volate, molybdenum sulfide, silicon carbide, stainless fiber, boric acid Examples thereof include zinc, various magnetic powders, slag fibers, fly ash, and dehydrated sludge. These inorganic fillers may be used alone or in combination of two or more.
Among these, metal carbonates, metal hydroxides, and metal oxides are preferable from the viewpoint of improving the mechanical strength of the fireproof sheet. Of these, calcium carbonate, aluminum hydroxide, and magnesium hydroxide are more preferable, and calcium carbonate, which is a metal carbonate, is even more preferable.
The inorganic filler is preferably granular. The average particle size of the granular inorganic filler is preferably in the range of 0.5 to 200 μm, more preferably in the range of 1 to 50 μm. The average particle size may be obtained by an air permeation method.

In the fireproof sheet of the present invention, it is preferable that the content of the heat-expandable graphite is 10 to 300 parts by mass and the content of the inorganic filler is 10 to 300 parts by mass with respect to 100 parts by mass of the matrix resin. .. By setting the content of the heat-expandable graphite to 10 parts by mass or more, the expansion ratio of the refractory sheet is increased and the fire resistance performance is improved. By using 300 parts by mass or less of the heat-expandable graphite, it is possible to prevent the flexibility from being lowered.
Further, by setting the amount of the inorganic filler to 10 parts by mass or more, the mechanical strength of the refractory sheet becomes good even with the expansion residue after thermal expansion. By setting the amount to 300 parts by mass or less, it is possible to prevent the flexibility of the refractory sheet from being lowered.
From these viewpoints, it is more preferable that the content of the heat-expandable graphite is 50 to 200 parts by mass and the content of the inorganic filler is 100 to 300 parts by mass.
Further, the total content of the heat-expandable graphite and the inorganic filler is preferably 20 to 500 parts by mass, more preferably 100 to 100 parts by mass, from the viewpoint of flexibility, mechanical strength and fire resistance with respect to 100 parts by mass of the matrix resin. It is 400 parts by mass.

In the present invention, the resin component is preferably an epoxy resin. The content of the heat-expandable graphite is preferably 10 to 300 parts by mass and the content of the inorganic filler is preferably 10 to 300 parts by mass with respect to 100 parts by mass of the epoxy resin. Is more preferably 50 to 200 parts by mass and the content of the inorganic filler is 100 to 300 parts by mass. Further, the total content of the heat-expandable graphite and the inorganic filler is preferably 20 to 500 parts by mass, more preferably 100 to 400 parts by mass with respect to 100 parts by mass of the epoxy resin.

[Dispersant]
The refractory sheet of the present invention may contain a dispersant. The dispersant improves the dispersibility of the heat-expandable graphite and the inorganic filler in the refractory sheet. Therefore, it becomes easy to contain a large amount of heat-expandable graphite and an inorganic filler in the refractory sheet. Further, the dispersant makes it easy to form bubbles, and makes it easy to adjust the average diameter of bubbles and the bubble area ratio within the above range.

As the dispersant, various surfactants can be used. The surfactant may have a hydrophilic group moiety and a hydrophobic group moiety compatible with the resin component. Specifically, polyether phosphate ester or its amine salt, polyether polyol polyesteric acid or its amine salt, polyester or its amine salt, polycarboxylic acid or its amine salt, polyaminoamide and phosphate phosphate, polyester. Examples thereof include acid amides and amine salts thereof. The amine used in these dispersants may be a polyamine. Among these, a polyether phosphate ester or an amine salt thereof is preferable. The dispersant may be used alone or in combination of two or more.
The content of the dispersant in the refractory sheet is preferably 0.5 to 15 parts by mass, and more preferably 1 to 8 parts by mass with respect to 100 parts by mass of the matrix resin.

[Phosphorus compound]
The refractory sheet of the present invention preferably contains a phosphorus compound. By containing a phosphorus compound, the fire resistance performance of the fire resistance sheet is improved. The phosphorus compound referred to here is a phosphorus compound other than the above-mentioned dispersant, and specifically, red phosphorus, phosphoric acid ester, condensed phosphoric acid ester, halogen-containing phosphoric acid ester, halogen-containing condensed phosphoric acid ester, and the like. Metal phosphate, metal phosphite, ammonium polyphosphate, aluminum polyphosphate, melamine polyphosphate, melam polyphosphate, melem polyphosphate, lower phosphate, compound represented by the following general formula (1), etc. Can be mentioned.

Examples of the phosphoric acid ester include various phosphoric acid esters such as triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate and xylenyl diphenyl phosphate. As the condensed phosphoric acid ester, a condensed phosphoric acid ester derived from bisphenol A such as PX-200 (trade name: manufactured by Daihachi Chemical Industry Co., Ltd.) and CR-733S (trade name: manufactured by Daihachi Chemical Industry Co., Ltd.), CR-741S. Examples thereof include condensed phosphoric acid esters derived from xylenol (trade name: manufactured by Daihachi Chemical Industry Co., Ltd.). Examples of the halogen-containing phosphoric acid ester and the halogen-containing condensed type phosphoric acid ester include those containing a halogen such as chlorine in the structure of the above-mentioned phosphoric acid ester and condensed type phosphoric acid ester.

Examples of the metal phosphate salt include sodium phosphate, potassium phosphate, magnesium phosphate, aluminum phosphate and the like, and examples of the metal phosphate salt include sodium phosphite, aluminum phosphite and the like, among which examples are given. , Aluminum phosphite is preferred.
Examples of ammonium polyphosphates include ammonium polyphosphate, melamine-modified ammonium polyphosphate, ammonium polyphosphate, piperazine polyphosphate, ammonium polyphosphate, etc., but from the viewpoint of flame retardancy, safety, cost, handleability, etc. Ammonium polyphosphate is preferred.

化学式（１）中、Ｒ¹およびＲ³は、同一又は異なって、水素、炭素数１～１６の直鎖状もしくは分岐状のアルキル基、または、炭素数６～１６のアリール基を示す。Ｒ²は、水酸基、炭素数１～１６の直鎖状もしくは分岐状のアルキル基、炭素数１～１６の直鎖状あるいは分岐状のアルコキシル基、炭素数６～１６のアリール基、または、炭素数６～１６のアリールオキシ基を示す。
上記化学式で表される化合物としては、例えば、メチルホスホン酸、メチルホスホン酸ジメチル、メチルホスホン酸ジエチル、エチルホスホン酸、プロピルホスホン酸、ブチルホスホン酸、２－メチルプロピルホスホン酸、ｔ－ブチルホスホン酸、２，３－ジメチル－ブチルホスホン酸、オクチルホスホン酸、フェニルホスホン酸、ジオクチルフェニルホスホネート、ジメチルホスフィン酸、メチルエチルホスフィン酸、メチルプロピルホスフィン酸、ジエチルホスフィン酸、ジオクチルホスフィン酸、フェニルホスフィン酸、ジエチルフェニルホスフィン酸、ジフェニルホスフィン酸、ビス（４－メトキシフェニル）ホスフィン酸等が挙げられる。 Further, the compound represented by the general formula (1) is as follows.

In the chemical formula (1), R ¹ and R ³ represent hydrogen, a linear or branched alkyl group having 1 to 16 carbon atoms, or an aryl group having 6 to 16 carbon atoms, which are the same or different. R ² is a hydroxyl group, a linear or branched alkyl group having 1 to 16 carbon atoms, a linear or branched alkoxyl group having 1 to 16 carbon atoms, an aryl group having 6 to 16 carbon atoms, or carbon. The number 6 to 16 aryloxy groups are shown.
Examples of the compound represented by the above chemical formula include methylphosphonic acid, dimethyl methylphosphonate, diethyl methylphosphonate, ethylphosphonic acid, propylphosphonic acid, butylphosphonic acid, 2-methylpropylphosphonic acid, t-butylphosphonic acid, 2, 3-Dimethyl-butylphosphonic acid, octylphosphonic acid, phenylphosphonic acid, dioctylphenylphosphonate, dimethylphosphinic acid, methylethylphosphinic acid, methylpropylphosphinic acid, diethylphosphinic acid, dioctylphosphinic acid, phenylphosphinic acid, diethylphenylphosphinic acid , Diphenylphosphinic acid, bis (4-methoxyphenyl) phosphinic acid and the like.

The above phosphorus compounds may be used alone or in combination of two or more. Among the above, the phosphorus compound is preferably one or more selected from a metal phosphite salt and aluminum polyphosphates.
The phosphorus compound is considered to react with the above-mentioned metal carbonates such as calcium carbonate and zinc carbonate to promote the expansion of the metal carbonate, and particularly when ammonium polyphosphates are used as the phosphorus compound, the expansion is high. It becomes easier to obtain the effect. It also acts as an effective aggregate and forms an expanded residue with high shape retention after combustion.

The content of the phosphorus compound in the refractory sheet is preferably 20 to 300 parts by mass, more preferably 40 to 250 parts by mass with respect to 100 parts by mass of the matrix resin. By setting the content of the phosphorus compound to these lower limit values or more, it becomes easier to improve the fire resistance performance of the fire resistance sheet. Further, by setting the value to the upper limit or less, it becomes easy to secure the flexibility and shape retention of the refractory sheet.

[Other additives]
The fireproof sheet of the present invention is a phenol-based, amine-based, sulfur-based or other antioxidant, metal damage inhibitor, antistatic agent, stabilizer, lubricant, as required, as long as the object of the present invention is not impaired. It may contain other additives other than the above-mentioned additives such as softeners, pigments and antistatic resins. The content of the other additives is, for example, 50 parts by mass or less, preferably 30 parts by mass or less, based on 100 parts by mass of the matrix resin.

The thickness of the refractory sheet of the present invention is not particularly limited, but is, for example, 0.5 to 20 mm, preferably 0.8 to 5 mm.
Further, the length of the refractory sheet is preferably 2 m or more in total length, and it is more preferable that the refractory sheet is rolled into a roll shape. Since the refractory sheet of the present invention has high flexibility, cracks and cracks do not occur even if the entire length is lengthened and rolled into a roll. Further, by increasing the average diameter of bubbles and the ratio of bubble area, the flexibility is further improved, and floating at the end does not occur when the bubbles are wound in a roll shape. The upper limit of the length of the refractory sheet is not particularly limited, but is, for example, 400 m, preferably 20 m.
The width of the refractory sheet is not particularly limited, but is, for example, about 5 mm to 150 cm.

<Manufacturing method of refractory sheet>
The refractory sheet of the present invention includes, for example, a first step of obtaining a refractory resin composition containing a matrix resin, a heat-expandable graphite, and an inorganic filler and containing a plurality of bubbles, and a refractory resin mixed with bubbles. It may be produced by a production method including a second step of molding the composition into a sheet to obtain a refractory sheet. Hereinafter, the method for manufacturing the refractory sheet will be described in detail.

[First step]
In the first step, for example, a matrix resin containing a resin component, a heat-expandable graphite, and an inorganic filler may be kneaded in a kneader to obtain a refractory resin composition. At this time, the refractory resin composition is mixed with air by being entrained with outside air by kneading. When any component such as the above-mentioned dispersant, phosphorus compound, and other additives is blended in the refractory sheet, any component is added in addition to the matrix resin, the heat-expandable graphite, and the inorganic filler. You can also knead them together.

In general, when the viscosity is particularly high, the general kneading is performed while degassing so that the air entrained from the outside by the kneading does not remain in the composition. On the other hand, in the production method of the present invention, kneading is performed without degassing, so that the air entrained during kneading exists as bubbles in the refractory resin composition.
Further, in the present production method, in order to set the average diameter of bubbles and the bubble area ratio within a predetermined range, the viscosity of the refractory resin composition at the time of kneading may be set within a desired range as shown below, or as described above. It is advisable to add a dispersant to the refractory resin composition.

That is, when kneading in a kneader to obtain a refractory resin composition, the viscosity of the refractory resin composition is preferably in the range of 1000 to 7000 mPa · s. By adjusting the viscosity of the refractory resin composition within this range, bubbles are mixed in the refractory resin composition during kneading, and the mixed bubbles are easily present in the refractory sheet, and the average diameter and bubble area ratio of the bubbles are easily present. Is easy to adjust within the above-mentioned predetermined range. Further, by setting the viscosity to the upper limit or less, the refractory resin composition can be transferred by using a pipe or the like, and the productivity is improved.
The viscosity is more preferably 2500 to 6000 mPa · s, and even more preferably 3000 to 5000 mPa · s, from the viewpoint of facilitating the adjustment of the average diameter of the bubbles and the bubble area ratio to the above-mentioned desired ranges. The viscosity in the present specification is the viscosity measured at a shear rate of 1500 rpm using a rheometer at the temperature (kneading temperature) of the refractory resin composition at the time of kneading.
The temperature (kneading temperature) of the refractory resin composition at the time of kneading may be any temperature as long as the viscosity of the refractory resin composition is within the above range, and is, for example, 10 to 100 ° C., preferably 20 to 60 ° C.

A solvent may be appropriately added to the refractory resin composition so that the viscosity is within the above range. The solvent to be used may be appropriately selected according to the type of resin component. Although not particularly limited, specific examples thereof include ether solvents such as tetrahydrofuran and diethyl ether, aromatic hydrocarbon solvents such as toluene, benzene and xylene, ketone solvents such as acetone and methyl ethyl ketone, and hexane, heptane and octane. Examples include aliphatic hydrocarbon solvents.
The amount of the solvent used is not particularly limited, but is used, for example, 1 to 200 parts by mass with respect to 100 parts by mass of the components other than the solvent.
The solvent is preferably used when at least one of a thermoplastic resin and a rubber substance is used as the resin component. Since the thermoplastic resin and the rubber substance are not cured in the second step described later, the refractory resin composition tends to have a high viscosity without a solvent. Therefore, it is preferable to reduce the viscosity by adding a solvent so that the viscosity is within the above range.

The kneader used in the fire-resistant resin composition is not particularly limited, but is a single-screw extruder, a twin-screw extruder, a Banbury mixer, a kneader mixer, a kneading roll, a Raikai machine, a planetary stirrer, and a stirrer including a stirring blade. A known kneader can be used. Among these, for example, it is preferable to perform kneading using a stirrer in which the stirrer blade is a disper blade, because the filler can be uniformly dispersed.

After the first step, the refractory resin composition is pressed to be sent to the mold through a pipe or extruded by a screw in an extruder. In the production method of the present invention, the average diameter of the refractory sheet is average. In addition, by mixing the bubbles so that the bubble area ratio is within a predetermined range, the pressure loss inside the pipe or when the screw is extruded is reduced. Therefore, the productivity of the refractory sheet is improved.

[Second step]
In the second step, the refractory resin composition mixed with air bubbles is molded into a sheet to obtain a refractory sheet. Here, the refractory resin composition is not particularly limited, but may be, for example, poured into a mold to form a sheet. When a single-screw extruder, a twin-screw extruder, or the like is used as the kneader, the refractory resin composition may be extruded into a sheet from the extruder.
The refractory resin composition in the form of a sheet may be cured or solidified. For example, when a thermosetting resin is used as a resin component, it may be cured by heating or the like. When a thermoplastic resin or a rubber substance is used as the resin component, it is preferable to cool the fireproof resin composition that has been softened or liquefied by heating during kneading to solidify or harden it. When the refractory resin composition contains a solvent, the solvent may be volatilized and solidified by heating or the like.
The heating temperature for curing or solidifying may be appropriately adjusted depending on the type of thermosetting resin, the type of solvent, and the like, and is, for example, 40 to 150 ° C, preferably 45 to 95 ° C. The heating time is not particularly limited, but is, for example, about 1 to 15 hours.

<How to use the fireproof sheet>
The fireproof sheet of the present invention can be used for various buildings such as detached houses, apartment houses, high-rise houses, high-rise buildings, commercial facilities, public facilities, various vehicles such as automobiles and trains, and various vehicles such as ships and aircraft. However, among these, it is preferable to be used for buildings.
The refractory sheet is used by being attached to a member constituting the building, a vehicle, a ship, an aircraft, or the like. For example, in a building, it can be attached to windows, shoji screens, doors, doors, fittings such as bran, pillars, walls such as steel-framed concrete, floors, roofs, etc. to reduce or prevent the invasion of fire and smoke. Among these, it is preferable to use it for fittings. That is, in a preferred embodiment, the fitting includes the above-mentioned refractory sheet of the present invention.

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

The measurement and evaluation methods in this example are as follows.
[Average diameter of bubbles]
The fireproof sheet was cut in the thickness direction, the cut cross section was observed using an SEM (Radiation Electron Microscope), and the average diameter was calculated from the diameters of 20 bubbles.
As for the refractory sheet, the diameters of 10 bubbles are measured in the cross section obtained by cutting the refractory sheet along the MD direction and the thickness direction, and the refractory sheet is measured along the TD direction and the thickness direction. The diameter of 10 bubbles was measured in the cross section obtained by cutting. However, when the MD direction and the TD direction cannot be determined, any one direction parallel to the plane direction is assumed to be the MD direction, and the direction perpendicular to the MD direction is assumed to be the TD direction.
[Bubble area ratio]
In the same manner as above, the cut cross section was observed, and (total area of bubbles / total area of the observed sheet) × 100 was calculated as the bubble area ratio. Also in the calculation of the bubble area ratio, two observation images having the same cross-sectional area were observed as described above, and the total cross-sectional area of the observed sheets was 10 mm ² .
The total area of bubbles can be obtained by image processing. That is, the area of the bubble can be obtained by calculating the area of the dark-colored portion by utilizing the fact that the bubble is observed in a dark color by SEM.

[Fire resistance]
The refractory sheets obtained in Examples and Comparative Examples were cut into 60 mm × 60 mm, placed in a metal frame having an inner size of 62 mm × 62 mm and a height of 100 mm, and heated at 600 ° C. for 10 minutes to thermally expand each refractory sheet. The expansion coefficient was calculated from "height of expansion residue / thickness of refractory sheet before heating". Those having an expansion ratio of 20 times or more were evaluated as "A", and those having an expansion ratio of less than 20 times were evaluated as "C".

[Flexibility]
A fireproof sheet having a length of 2 m and a width of 10 cm obtained in Examples and Comparative Examples is wrapped around a paper core having an outer diameter of 10 cm, and the center of the end of the winding is a 19 mm × 50 mm vinyl tape (trade name “Eslon Tape # 300”). , Made by Sekisui Chemical Co., Ltd.).
If the refractory sheet has no cracks or cracks and the appearance can be rolled cleanly, and there is no floating at the end of the sheet at the end of winding, "A". Those with floats were evaluated as "B", and those with at least one of cracks or cracks in the refractory sheet were evaluated as "C".

[Piping pressure loss]
The refractory resin composition after kneading was passed through a pipe having an inner diameter of 30 mm and a length of 3 m at a flow rate of 6000 g / min using a MONO pump "trade name. Manufactured by Hyojin Equipment Co., Ltd.". The piping pressure at that time was measured with a pressure gauge. "A" when the pipe pressure is 2 MPa or less, "B" when it is larger than 2 MPa and less than 4 MPa, "C" when it is 4 MPa or more, and "D" when the refractory resin composition cannot be passed through the pipe. ".

[Examples 1, 2, 6 to 8]
The raw materials are weighed according to the formulation shown in Table 1, put into a stirrer equipped with a disper blade, and kneaded under the conditions of atmospheric pressure and 40 ° C. without degassing to obtain a refractory resin composition. rice field. In all the examples, the viscosity of the refractory resin composition at 40 ° C. (kneading temperature) was in the range of 3000 to 5000 mPa · s. The kneaded refractory resin composition was poured into a mold having a length of 2 m and a width of 10 cm, and pressed to a thickness of 2 mm. After pressing, it was heated in an oven at 90 ° C. for 10 hours to cure the thermosetting resin to obtain a refractory sheet.

[Examples 3 to 5]
The raw materials are weighed according to the formulation shown in Table 1, put into a stirrer equipped with a disper blade, and a solvent is further added so that the viscosity at the kneading temperature (30 ° C.) becomes 3000 to 5000 mPa · s. The resin was melted and kneaded under the conditions of atmospheric pressure and 30 ° C. without degassing to obtain a fire-resistant resin composition. The blending amount of the solvent was 50 parts by mass with respect to 100 parts by mass of the components other than the solvent, and the solvent was tetrahydrofuran in Example 3, acetone in Example 4, and toluene in Example 5. The kneaded refractory resin composition was poured into a mold having a length of 2 m and a width of 10 cm, and pressed to a thickness of 2 mm. After pressing, the refractory resin composition was solidified by volatilizing the solvent by heating at 50 ° C. for 10 hours without applying pressure to obtain a refractory sheet.

[Comparative Example 1]
The raw materials were weighed according to the formulation shown in Table 1, put into a stirrer equipped with a disper blade, and kneaded at 40 ° C. while degassing with a vacuum degassing device to obtain a refractory resin composition. The viscosity of the refractory resin composition at 40 ° C. was 3000 to 5000 mPa · s. Then, it was carried out in the same manner as in Example 1 to obtain a refractory sheet.

[Comparative Examples 2 to 4]
The raw materials were weighed according to the formulation shown in Table 1 and put into a stirrer equipped with a disper blade, and a solvent was further added so that the viscosity at the kneading temperature was 3000 to 5000 mPa · s to dissolve the resin. A fire-resistant resin composition was obtained by kneading at 30 ° C. while degassing with a vacuum degassing device. The blending amount of the solvent was 50 parts by mass with respect to 100 parts by mass of the components other than the solvent, and the solvent was tetrahydrofuran in Comparative Example 2, acetone in Comparative Example 3, and toluene in Comparative Example 4. Then, a refractory sheet was obtained in the same manner as in Example 3.

[Comparative Example 5]
The raw materials were weighed according to the formulation shown in Table 1, put into a kneading kneader, and kneaded at 150 ° C. using a kneading kneader without adding a solvent to obtain a refractory resin composition. After kneading, the refractory resin composition was pressed at 140 ° C. using a mold having a length of 2 m and a width of 10 cm to obtain a refractory sheet.

[Comparative Example 6]
The raw materials were weighed according to the formulation shown in Table 1, put into a stirrer equipped with a disper blade, and kneaded at 40 ° C. under atmospheric pressure without degassing to obtain a refractory resin composition. Next, the refractory resin composition was removed from the kneading container, and more than half of the stirring blades were made to come out of the refractory resin composition and further kneaded, so that the refractory resin composition was sufficiently contained with air. The viscosity of the refractory resin composition at 40 ° C. (kneading temperature) was 3000 to 5000 mPa · s. The kneaded refractory resin composition was poured into a mold having a length of 2 m and a width of 10 cm, and pressed to a thickness of 2 mm. After pressing, it was heated in an oven at 90 ° C. for 10 hours to cure the thermosetting resin to obtain a refractory sheet.

The raw materials listed in Table 1 are as follows.
(Matrix resin)
Epoxy resin (main agent): Bifunctional glycidyl ether, bisphenol A type epoxy compound, trade name "jER825", Mitsubishi Chemical Co., Ltd. epoxy resin (hardener): modified aliphatic polyamine, flexible grade, trade name "FL51" , Mitsubishi Chemical Co., Ltd. PVC: Polyvinyl chloride resin, trade name "S1001T", Kaneka Co., Ltd. plasticizer: diisodecyl phthalate, trade name "DIDP", J-Plus Co., Ltd. EVA: ethylene vinyl acetate copolymer , Product name "EV260", Vinyl acetate content 28% by mass, EPDM: Ethylene-propylene-diene rubber manufactured by Mitsui-Dupont Polychemical Co., Ltd., Product name "EPT3092PM", manufactured by Mitsui Chemicals Co., Ltd. (heat-expandable graphite)
Thermally expandable graphite (1): trade name "CA60N", manufactured by Air Water Inc. Thermally expandable graphite (2): trade name "ADT-501", manufactured by ADT (inorganic filler)
Calcium carbonate: Average particle size 8 μm (air permeation method), trade name "BF300", dispersant manufactured by Shiraishi Calcium Co., Ltd .: polyamine salt of polyether phosphate, trade name "DA325", manufactured by Kusumoto Kasei Co., Ltd. (phosphorus compound) )
Aluminum phosphate: Product name "APA-100", manufactured by Taihei Kagaku Sangyo Co., Ltd. Ammonium polyphosphate: Product name "AP422", manufactured by Clariant Chemicals Co., Ltd.

As is clear from the results in Table 1, in each example, the average diameter of the bubbles was 90 μm or more, and the bubble area ratio was 3 to 25%, so that the fire resistance and flexibility were excellent. In addition, the pressure loss was reduced and the productivity was improved.

Claims (7)

A refractory sheet containing a matrix resin, a heat-expandable graphite, and an inorganic filler and containing a plurality of bubbles inside.
The matrix resin is an epoxy resin,
A refractory sheet having an average diameter of 90 μm or more and a bubble area ratio of 3 to 25% in a cross section. The refractory sheet according to claim 1, wherein the heat-expandable graphite is 10 to 300 parts by mass and the inorganic filler is 10 to 300 parts by mass with respect to 100 parts by mass of the matrix resin. The fireproof sheet according to claim 1 or 2 , wherein the heat-expandable graphite is 50 to 200 parts by mass and the inorganic filler is 100 to 300 parts by mass with respect to 100 parts by mass of the epoxy resin. The fireproof sheet according to any one of claims 1 to 3 , which contains a dispersant. The fireproof sheet according to any one of claims 1 to 4 , which has a total length of 2 m or more. The fireproof sheet according to claim 5 , which is wound in a roll shape. A fitting provided with the fireproof sheet according to any one of claims 1 to 6 .