WO2020090696A1 - Rubber composition, molded foam, fire protective member, and method for producing molded foam - Google Patents

Abstract

The present invention provides a rubber composition which enables the achievement of a molded foam that has low specific gravity, while having an excellent balance among thermal expansion, shape retainability and flame retardancy. A rubber composition which contains 100 parts by mass of a thermosetting elastomer, 10-120 parts by mass of a thermal expansion agent, 15-100 parts by mass of a solid metal phosphite or phosphate, 30-100 parts by mass of an inorganic filler and 5-30 parts by mass of a foaming agent; and a molded foam which is obtained using the rubber composition.

Description

RUBBER COMPOSITION, FOAM MOLDED BODY, FIRE PROTECTION MEMBER, AND METHOD FOR PRODUCING FOAM MOLDED BODY

The present invention relates to a rubber composition, a foam molded article using the rubber composition, a fireproof member using the foam molded article, and a method for producing the foam molded article.

Conventionally, various techniques for improving the fire protection performance of resin compositions have been studied. For example, Patent Document 1 proposes a refractory resin composition having excellent residue stability and general physical properties. Patent Document 2 proposes a heat-expandable fire-resistant resin composition having both high expandability and high residue hardness. Patent Document 3 proposes a refractory resin composition having excellent expandability, surface finish, and strength.

Japanese Patent Laid-Open No. 2018-100410 JP, 2018-024891, A JP, 2017-1333028, A

However, the conventional fire-resistant resin composition does not have a good balance of thermal expansion, shape retention and flame retardancy, and its large specific gravity makes it difficult to transport and poor workability.

Therefore, the main object of the present invention is to provide a rubber composition having an excellent balance of thermal expansion properties, shape retention properties and flame retardancy, and a foamed molded product having a small specific gravity.

Specific gravity and flame retardancy, which are the characteristics of foamed molded products, are generally in a trade-off relationship, so it is difficult to improve flame retardancy while reducing specific gravity. Further, since the thermal expansion property and the shape retention property, which are the characteristics of the foamed article after combustion, are generally in a trade-off relationship, it is difficult to maintain the shape while increasing the volume expansion ratio after combustion. That is, it has been considered difficult to obtain a foamed molded product having a low specific gravity and good flame retardancy, thermal expansion properties and shape retention. However, as a result of intensive studies, the present inventor has found that by using a rubber composition containing a thermosetting elastomer, a thermal expansion agent, a solid metal (sub) phosphate, an inorganic filler and a foaming agent in specific amounts, respectively. It was found that a foamed molded product having good thermal expansion properties, shape retention properties, and flame retardancy and having these properties in a well-balanced manner and having a low specific gravity was obtained, and completed the present invention.

That is, the present invention comprises 100 parts by mass of a thermosetting elastomer, 10 to 120 parts by mass of a thermal expansion agent, 15 to 100 parts by mass of a solid metal (sub) phosphite, and 30 to 100 parts by mass of an inorganic filler. A rubber composition comprising 5 to 30 parts by mass of a foaming agent is provided.
The thermosetting elastomer may be chloroprene rubber or ethylene-propylene-diene rubber.
The thermal expansion agent may be thermally expandable graphite.
The solid metal (phosphite) salt may be aluminum phosphite.
The inorganic filler may be aluminum hydroxide and / or clay.
The foaming agent may be an organic foaming agent.
The rubber composition may be for a foamed molded product.

The present invention provides a foamed molded article using the rubber composition.
The present invention further provides a fireproof member using the foamed molded product.
The present invention also includes a step of vulcanizing the rubber composition, wherein the vulcanizing temperature in the vulcanizing treatment is 110 to 170 ° C. and the vulcanizing time is 3 to 40 minutes. A manufacturing method is provided.

According to the present invention, it is possible to provide a rubber composition which has an excellent balance of thermal expansion properties, shape retention properties and flame retardancy properties, and which can give a foamed molded product having a small specific gravity.

Hereinafter, modes for carrying out the present invention will be described. It should be noted that the embodiment described below is an example of the embodiment of the present invention, and the scope of the present invention is not narrowly interpreted by this.

<1. Rubber composition>
A rubber composition according to an embodiment of the present invention includes (1) a thermosetting elastomer, (2) a thermal expansion agent, (3) a solid metal (sub) phosphate, (4) an inorganic filler, and (5). ) Including a foaming agent. The rubber composition of the present embodiment is suitable for a foamed molded product and can be used as a raw material for a foamed molded product described later. Hereinafter, each component contained in the rubber composition of the present embodiment will be described.

(1) Thermosetting Elastomer Examples of thermosetting elastomers include chloroprene rubber (CR), ethylene-propylene-diene rubber (EPDM), styrene-butadiene rubber (SBR), natural rubber (NR), acrylonitrile-butadiene rubber ( NBR), silicone rubber, chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CPE), hydrogenated nitrile rubber (HNBR), acrylic rubber (ACM), urethane rubber, butyl rubber and the like. These thermosetting elastomers may be used alone or in combination of two or more.

Among these thermosetting elastomers, chloroprene rubber or ethylene-propylene-diene rubber is preferable. The rubber composition containing chloroprene rubber is suitably used for a fire prevention member that places importance on mechanical strength and flame retardancy. A rubber composition containing ethylene-propylene-diene rubber is suitably used for a fireproof member that places importance on weather resistance.

(2) Thermal Expansion Agent The thermal expansion agent has the property of expanding when heated, and is used to impart thermal expansion properties to the foamed molded product obtained from the rubber composition of the present embodiment. Examples of the heat-expanding agent include heat-expanding graphite and heat-expanding microcapsules in which a low-boiling-point hydrocarbon is included in a thermoplastic polymer cell, and these may be used alone or in combination of two or more. Among these, the thermally expansive graphite is preferable because it has a large thermal expansive effect. As the heat-expandable graphite, known ones may be used, for example, a powder of natural graphite or pyrolytic graphite, an inorganic acid such as sulfuric acid or nitric acid, and a strong oxidizer such as concentrated nitric acid or permanganate. And a crystalline compound which maintains the graphite layer structure. The powder of natural graphite, pyrolytic graphite, or the like may be subjected to deoxidation treatment or neutralization treatment.

The content of the thermal expansion agent in the rubber composition of the present embodiment is 10 to 120 parts by mass, preferably 10 to 100 parts by mass, and more preferably 10 to 80 parts by mass with respect to 100 parts by mass of the thermosetting elastomer. It is a mass part. When the content of the thermal expansion agent is less than 10 parts by mass, sufficient foaming properties cannot be imparted to the foamed molded product obtained from the rubber composition, and when it is more than 120 parts by mass, the above foamed molded product is obtained. Has a large specific gravity and becomes heavy, which may lead to a reduction in workability such as difficulty in transportation.

When the thermosetting elastomer contained in the rubber composition is chloroprene rubber, the content of the thermal expansion agent in the rubber composition is more preferably 40 to 80 parts by mass with respect to 100 parts by mass of the chloroprene rubber. Within such a range, a foamed molded article having a better balance of thermal expansion, shape retention and flame retardancy can be obtained. When the thermosetting elastomer contained in the rubber composition is ethylene-propylene-diene rubber, the content of the thermal expansion agent in the rubber composition is 40 to 80 parts by mass with respect to 100 parts by mass of the ethylene-propylene-diene rubber. It is more preferable that the amount is 65 to 80 parts by mass. Within such a range, a foamed molded article having a better balance of thermal expansion, shape retention and flame retardancy can be obtained.

(3) Solid Metal (Sub) Phosphate Solid metal (sub) phosphate is a shape-retaining agent for imparting shape-retaining properties after combustion to the foamed molded product obtained from the rubber composition of the present embodiment. Used. That is, the foamed molded body does not become powdery even after being burned by containing the solid metal (sub) phosphite, and can maintain the shape.

The content of the solid metal (sub) phosphate in the rubber composition of the present embodiment is 15 to 100 parts by mass, preferably 15 to 60 parts by mass, based on 100 parts by mass of the thermosetting elastomer. The amount is preferably 20 to 60 parts by mass, more preferably 30 to 50 parts by mass. When the content of the solid metal (sub) phosphate is less than 15 parts by mass, the shape retention of the foamed molded product obtained from the rubber composition after combustion is deteriorated. When it is more than 100 parts by mass, the specific gravity of the foam molded article becomes large and heavy, which may cause a decrease in workability such as difficulty in transportation, and also the thermal expansion property of the foam molded article decreases. ..

The solid metal (phosphite) salt is preferably one that can maintain its shape stably under high temperature heating. Examples of such solid metal (phosphite) salts include various phosphoric acids / phosphorous acids and at least one metal selected from metals of groups IA to IVB of the periodic table, ammonia, aliphatic amines, and aromatic amines. Alternatively, a phosphate / phosphite salt formed of a salt with a compound may be mentioned. Examples of various phosphoric acids / phosphorous acids include phosphoric acid, phosphorous acid, pyrophosphoric acid, and polyphosphoric acid.

Examples of metals of Groups IA to IVB of the Periodic Table include lithium, sodium, potassium, magnesium, calcium, barium, iron (II), iron (III), zinc and aluminum.

Examples of aliphatic amines include methylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, piperazine and the like.

Further, examples of the aromatic amine include pyridine, triazine, melamine, ammonium and the like.

The above-mentioned solid metal (phosphite) salt may be subjected to a known water resistance improving treatment such as treatment with a silane coupling agent and coating with a melamine resin, and a known foaming auxiliary agent such as melamine and pentaerythritol is added. May be.

Examples of the phosphate / phosphite constituting the solid metal (phosphite) include ammonium salts such as ammonium phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, monosodium phosphate and diphosphate. Sodium, trisodium phosphate, monosodium phosphite, disodium phosphite, sodium salts such as sodium hypophosphite, monopotassium phosphate, dipotassium phosphate, tripotassium phosphate, monopotassium phosphite, Dipotassium phosphite, potassium salts such as potassium hypophosphite, monolithium phosphate, dilithium phosphate, trilithium phosphate, monolithium phosphite, dilithium phosphite, lithium hypophosphite, etc. Lithium salt, barium dihydrogen phosphate, barium hydrogen phosphate, barium triphosphate, barium hypophosphite, etc., magnesium monohydrogen phosphate Magnesium, magnesium hydrogen phosphate, trimagnesium phosphate, magnesium hypophosphite and other magnesium salts, calcium dihydrogen phosphate, calcium hydrogen phosphate, tricalcium phosphate, calcium hypophosphite and other calcium salts, zinc phosphate, Zinc phosphite, zinc salts such as zinc hypophosphite, aluminum monophosphate, dibasic aluminum phosphate, aluminum triphosphate, aluminum phosphite, aluminum salts such as aluminum hypophosphite and the like. Be done.

Examples of the polyphosphate include ammonium polyphosphate, piperazine polyphosphate, melamine polyphosphate, ammonium polyphosphate amide, and aluminum polyphosphate.

The solid metal (phosphite) salt is preferably a solid metal phosphite salt, more preferably aluminum phosphite, ammonium phosphite, disodium phosphite, and dipotassium phosphite, and Aluminum phosphite is preferred. These solid metal (sub) phosphates may be used alone or in combination of two or more.

(4) Inorganic Filler The inorganic filler is used to impart flame retardancy to the foamed molded product obtained from the rubber composition of the present embodiment. Examples of the inorganic filler include silica, diatomaceous earth, alumina, titanium oxide, magnesium hydroxide, aluminum hydroxide, zinc borate, sodium borate, calcium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, hydrotalcite, and sulfuric acid. Examples thereof include calcium, barium sulfate, calcium silicate, talc, clay, mica, bentonite, activated clay, sepiolite, glass fiber, glass beads, aluminum nitride, and boron nitride. From the viewpoint of improving the flame retardancy, aluminum hydroxide, calcium hydroxide, calcium carbonate, magnesium carbonate, clay, silica and talc are preferable, and among these, aluminum hydroxide and / or clay have general versatility and rubber processability. From the viewpoint, it is more preferable. Furthermore, in order to improve flame retardancy, it is also effective to use antimony trioxide together. These inorganic fillers may be used alone or in combination of two or more.

The content of the inorganic filler in the rubber composition of the present embodiment is 30 to 100 parts by mass, preferably 30 to 80 parts by mass, and more preferably 30 to 60 parts by mass with respect to 100 parts by mass of the thermosetting elastomer. Parts by mass, more preferably 30 to 50 parts by mass. When the content of the inorganic filler is less than 30 parts by mass, the flame-retardant property of the foamed molded product obtained from the rubber composition decreases, and when it is more than 100 parts by mass, the specific gravity of the foamed molded product increases. There is a possibility that workability may be deteriorated such that it becomes heavy and difficult to carry.

(5) Foaming agent The foaming agent is an essential component for obtaining a foam molded article from the rubber composition of the present embodiment. Generally, foaming agents are roughly classified into chemical foaming agents and physical foaming agents, and chemical foaming agents can be classified into organic foaming agents and inorganic foaming agents. The foaming agent used in the rubber composition of the present embodiment is preferably an organic foaming agent or an inorganic foaming agent.

Examples of the organic foaming agent include azo foaming agents such as azodicarbonamide (ADCA), azobisisobutyronitrile, azodiaminobenzene, and azocyclohexylnitrile; N, N′-dinitrosopentamethylenetetramine, N, N Nitroso-based blowing agents such as'-dimethyl N, N'-dinitrosoterephthalamide; p, p'-oxybisbenzenesulfonyl hydrazide (OBSH), benzenesulfonyl hydrazide, toluenesulfonyl hydrazide, diphenyl sulfone-3,3'-di Sulfonyl hydrazide type foaming agents such as sulfonyl hydrazide; and the like. Examples of the inorganic foaming agent include ammonium bicarbonate, ammonium carbonate, sodium hydrogen carbonate, ammonium nitrite, calcium azide and the like. Among these, an organic foaming agent is more preferable, and azodicarbonamide (ADCA) and / or p, p'-oxybisbenzenesulfonyl hydrazide (OBSH) is more preferable. These foaming agents may be used alone or in combination of two or more kinds.

The content of the foaming agent in the rubber composition of the present embodiment is 5 to 30 parts by mass, preferably 10 to 30 parts by mass, and more preferably 10 to 20 parts by mass with respect to 100 parts by mass of the thermosetting elastomer. It is a department. When the content of the foaming agent is less than 5 parts by mass, the specific gravity of the foamed molded product obtained from the rubber composition becomes large and heavy, and there is a possibility that workability may be deteriorated such as difficulty in transportation. If it is more than 30 parts by mass, the thermal expansion property of the foamed molded product will be reduced.

The rubber composition of the present embodiment may contain additives other than the above components, if necessary. Examples of the additive include a lubricant, an antioxidant, a reinforcing agent such as carbon book, a plasticizer, a processing aid, a vulcanizing agent, a vulcanization accelerator, and a vulcanization retarder.

<2. Foam molding>
A foamed molded article according to one embodiment of the present invention comprises the above rubber composition. For this reason, the foamed molded article of the present embodiment is characterized by an excellent balance of thermal expansion, shape retention and flame retardancy, and low specific gravity.

The expanded molded article of the present embodiment has a volume expansion ratio after burning at 300 ° C. for 30 minutes of preferably 3 times or more, more preferably 4 times or more, and further preferably 5 times or more. The volume expansion ratio is preferably large from the viewpoint of thermal expansion property, but the volume expansion ratio is preferably 10 times or less from the viewpoint of the balance with the shape retainability.

The foamed molded article of this embodiment has good shape retention after combustion. Good shape retention means specifically that powder does not become powdery after burning at 600 ° C. for 30 minutes.

The foamed molded article of the present embodiment has an oxygen index measured in accordance with JIS K6269 of Japanese Industrial Standards of preferably 25 or more, more preferably 30 or more, and further preferably 35 or more. The oxygen index is the numerical value of the minimum oxygen concentration expressed by volume% in the mixed gas of oxygen and nitrogen required for the material to sustain combustion under the specified test conditions, and is an index showing flame retardancy. is there. The larger the value of the oxygen index, the higher the flame retardancy (hard to burn).

The foamed molded article of the present embodiment has a specific gravity of preferably less than 1.1, more preferably less than 0.8, still more preferably less than 0.5, measured according to Japanese Industrial Standard JIS K6229. Is. By reducing the specific gravity in this way, it is possible to reduce the weight of the foamed molded product and improve workability such as transportation.

The foamed molded product of the present embodiment is obtained by kneading the above rubber composition, preforming the obtained compound into a desired shape, and subjecting it to vulcanization.

As a device for kneading the rubber composition, for example, a kneading device such as a mixer, a Banbury mixer, a kneader mixer, or a twin roll can be used. As an apparatus for molding the kneaded rubber composition, for example, a molding apparatus for performing press molding, extrusion molding, calender molding and the like can be mentioned. Generally, a rubber composition is extruded and molded into a product shape by an extruder for rubber, then introduced into a vulcanization tank, and vulcanized by heating with a means such as hot air, a fluidized bed, or a microwave. Foaming can be performed. The shape of the foamed molded article is not particularly limited, and may be appropriately selected depending on the application, the installation location, etc., such as a sheet shape or a tape shape.

In the vulcanization treatment of the rubber composition, the vulcanization temperature is preferably 110 to 170 ° C., and the vulcanization time is preferably 3 to 40 minutes. Within such a range, it is possible to obtain a foamed molded product having a better balance of thermal expansion properties, shape retention properties and flame retardancy and a small specific gravity.

When the thermosetting elastomer contained in the rubber composition is chloroprene rubber, the vulcanization temperature is more preferably 135 to 170 ° C., further preferably 140 to 165 ° C., and the vulcanization time is more preferably 3 to 15 minutes. And more preferably 3 to 10 minutes. When the thermosetting elastomer contained in the rubber composition is ethylene-propylene-diene rubber, the vulcanization temperature is more preferably 110 to 145 ° C, further preferably 115 to 140 ° C, and the vulcanization time is more preferably 10 ˜40 minutes, more preferably 15-35 minutes.

The foamed molded product of this embodiment is preferably used as a fire protection member. For example, the foamed molded article of the present embodiment can be placed in a gap between structures that compose a building such as a building. The foamed molded article of the present embodiment having excellent thermal expansion property, when exposed to high temperature during a fire, thermally expands to fill the gaps in the structure, block flames and smoke, and prevent the spread of fire damage. it can. Furthermore, since the foamed molded article of the present embodiment has good shape retention and flame retardancy, the foamed molded article that has undergone thermal expansion does not fall into a powdery state even when a flame approaches, and the foamed molded article does not collapse. It is less likely that it will burn itself and cause fire spread. Further, generally, in a work site where a fireproof member is installed, a fireproof member having a large specific gravity and a heavy weight may be difficult to carry and workability may be poor, but the foamed molded article of the present embodiment has a low specific gravity and thus is easy to carry and work. There is also an advantage that the property is good.

For example, in buildings such as buildings, various pipes that accommodate cables are placed, and there are gaps between cables and pipes. A fireproof member using the foamed molded article is preferably used as a fireproof member for closing such a gap in a pipe. Further, the fireproof member is also useful as a fireproof member for subway vehicles.

Hereinafter, the present invention will be described in more detail based on examples. The embodiments described below are examples of typical embodiments of the present invention, and the present invention is not limited to the following embodiments.

In the examples and comparative examples, the following materials were used.
(1) Thermosetting elastomer chloroprene rubber (“S-40V” manufactured by Denka Co., Ltd.)
Ethylene-propylene-diene rubber ("4045H" manufactured by Mitsui Chemicals, Inc.)
(2) Thermal expansion agent Thermal expansion graphite ("SYZR509517" manufactured by Sanyo Trading Co., Ltd.)
(3) Shape-retaining agent Aluminum phosphite ("APA-100" manufactured by Taihei Chemical Industry Co., Ltd.)
(4) Inorganic filler Aluminum hydroxide (“C-301N” manufactured by Sumitomo Chemical Co., Ltd.)
Clay (“DIXIE CLAY” made by Vanderbilt Minerals, LLC)
(5) Foaming agent Azodicarbonamide (“Selmic C-1” manufactured by Sankyo Kasei Co., Ltd.)
p, p'-oxybisbenzenesulfonyl hydrazide (“Selmic S” manufactured by Sankyo Kasei Co., Ltd.)
(6) Lubricant Stearic acid ("Lunack S-90" manufactured by Kao Corporation)
(7) Antiaging agent Octylated diphenylamine (“OCTAMINE” manufactured by Shiraishi Calcim Co., Ltd.)
(8) Filler Carbon black (FEF) ("Asahi # 60" manufactured by Asahi Carbon Co., Ltd.)
(9) Plasticizer naphthenic oil (“Diana Process Oil NP-24” manufactured by Idemitsu Kosan Co., Ltd.)
Liquid paraffin ("High Coal K-230" manufactured by Kaneda Corporation)
(10) Processing aid Black Sub ("Black Sub BFA" manufactured by Nippon Sub Chemical Co., Ltd.)
Paraffin wax ("Paraffin wax 135" manufactured by Nippon Seiro Co., Ltd.)
(11) Vulcanizing agent Zinc oxide ("Zinc oxide" manufactured by Sakai Chemical Industry Co., Ltd.)
Ethylene thiourea (Kawaguchi Chemical Co., Ltd. "Axel 22S")
Sulfur (“Sulfur powder” made by Hosoi Chemical Co., Ltd.)
2-Mercaptobenzothiazole ("Nox Cellar M" manufactured by Ouchi Shinko Chemical Co., Ltd.)
(12) Vulcanization retarder Magnesium oxide (Kyowa Mag 150 manufactured by Kyowa Chemical Industry Co., Ltd.)
Tetramethylthiuram monosulfide ("Nox Cellar TS" manufactured by Ouchi Shinko Chemical Co., Ltd.)

The ingredients having the compounding amounts shown in Tables 1 and 2 below were kneaded at 40 ° C. for 30 minutes using an 8-inch roll to obtain a rubber composition. The obtained rubber composition was molded into a sheet with an 8-inch roll, and then vulcanized using a press. The vulcanization temperature and vulcanization time in the vulcanization treatment were as shown in Tables 1 and 2 below. After that, foaming treatment was performed to produce a foamed molded product having a width of 120 mm, a length of 120 mm and a thickness of 12 mm.

The physical properties (specific gravity, flame retardancy, thermal expansion and shape retention after combustion) of the obtained foamed molded product were evaluated by the following procedures.

(A) Specific gravity Based on Japanese Industrial Standard JIS K6229, specific gravity was measured using an automatic specific gravity meter (“DENSIMETER-H” manufactured by Toyo Seiki Seisaku-sho, Ltd.). The specific gravity was evaluated such that A is less than 0.5, B is 0.5 or more and less than 0.8, C is 0.8 or more and less than 1.1, and D is 1.1 or more. It was judged that A to C were acceptable and D was not acceptable.

(B) Flame retardance The oxygen index was used as an index showing flame retardancy. The oxygen index was measured using a flammability tester (“ON-1” manufactured by Suga Test Instruments Co., Ltd.) based on JIS K6269 of Japanese Industrial Standards. The higher the oxygen index, the higher the flame retardancy. Regarding the oxygen index, 35 or more was evaluated as A, 30 or more and less than 35 was evaluated as B, 25 or more and less than 30 was evaluated as C, and less than 25 was evaluated as D. It was judged that A to C were acceptable and D was not acceptable.

(C) Thermal Expansion The volume expansion ratio under combustion was measured as an index showing thermal expansion. Specifically, the volume expansion coefficient was calculated by dividing the volume after burning at 300 ° C. for 30 minutes by the volume before burning. The volume before and after combustion was calculated by actually measuring the length, width, and height. The volume expansion ratio was evaluated as A for 5 times or more, B for 4 times or more and less than 5 times, C for 3 times or more and less than 4 times, and D for 3 times or less. It was judged that A to C were acceptable and D was not acceptable.

(D) Shape Retention after Burning The foamed molded article after burning at 600 ° C. for 30 minutes was pressed with a finger to visually confirm whether it was powdery. A powdery material was evaluated as A, and a non-powdered material was evaluated as D. It was judged that A was a pass and D was a failure.

A foamed molded product having no D evaluation was used as an example, and a foamed molded product having a D evaluation of 1 or more was used as a comparative example. Examples are shown in Table 1 below, and comparative examples are shown in Table 2 below. In addition, in Tables 1 and 2, the unit of numerical values is "parts by mass".

The foamed molded products of Examples 1 to 26 have good thermal expansion properties, shape retention properties and flame retardancy, that is, excellent balance of thermal expansion properties, shape retention properties and flame retardancy. Was confirmed. It was also confirmed that the foamed molded articles of Examples 1 to 26 had a small specific gravity.

Comparative Example 1 in which the content of the thermal expansion agent was less than 10 parts by mass was inferior in thermal expansion property, and Comparative Example 2 in which the content of the thermal expansion agent was over 120 parts by mass had a large specific gravity. From these results, it was confirmed that the content of the thermal expansion agent is preferably 10 to 120 parts by mass.

Comparative Example 3 in which the content of aluminum phosphite is less than 15 parts by mass cannot retain its shape after combustion, and Comparative Example 4 in which the content of aluminum phosphite exceeds 100 parts by mass has large specific gravity and thermal expansion property. Was inferior to From these results, it was confirmed that the content of the solid metal (phosphite) salt is preferably 15 to 100 parts by mass.

Comparative Example 5 in which the content of the inorganic filler was less than 30 parts by mass was inferior in flame retardancy, and Comparative Example 6 in which the content of the inorganic filler was more than 100 parts by mass had a large specific gravity. From these results, it was confirmed that the content of the inorganic filler is preferably 30 to 100 parts by mass.

Comparative Example 7 in which the content of the foaming agent was less than 5 parts by mass had a large specific gravity, and Comparative Example 8 in which the content of the foaming agent exceeded 30 parts by mass was inferior in thermal expansion property. From these results, it was confirmed that the content of the foaming agent is preferably 5 to 30 parts by mass.

Claims (10)

1. 100 parts by mass of thermosetting elastomer,
   10 to 120 parts by mass of the thermal expansion agent,
   15 to 100 parts by mass of solid metal (sub) phosphate,
   30 to 100 parts by mass of inorganic filler,
   5 to 30 parts by mass of foaming agent,
   A rubber composition comprising:
2. The rubber composition according to claim 1, wherein the thermosetting elastomer is chloroprene rubber or ethylene-propylene-diene rubber.
3. The rubber composition according to claim 1 or 2, wherein the thermal expansion agent is thermally expandable graphite.
4. The rubber composition according to any one of claims 1 to 3, wherein the solid metal (phosphite) salt is aluminum phosphite.
5. The rubber composition according to any one of claims 1 to 4, wherein the inorganic filler is aluminum hydroxide and / or clay.
6. The rubber composition according to any one of claims 1 to 5, wherein the foaming agent is an organic foaming agent.
7. The rubber composition according to any one of claims 1 to 6, which is for a foam molded article.
8. A foam molded article using the rubber composition according to any one of claims 1 to 7.
9. A fireproof member using the foam molded article according to claim 8.
10. Vulcanizing the rubber composition according to any one of claims 1 to 7,
    A method for producing a foamed molded product, wherein the vulcanization temperature in the vulcanization treatment is 110 to 170 ° C., and the vulcanization time is 3 to 40 minutes.