JP2021004356A - Refractory composition and refractory material for gas pipe - Google Patents

Abstract

To provide a refractory composition that can be used for a gas pipe and a refractory material for gas pipes including the same.SOLUTION: The present invention provides a refractory composition containing a polymer, a thermally-expandable compound, and an inorganic filler, the polymer having a solubility parameter of more than 8.0. The present invention also provides a refractory material for gas pipes that is used for a joint of gas pipes, the refractory material formed from the refractory composition.SELECTED DRAWING: None

Description

The present invention relates to a refractory composition for suppressing the spread of fire by expanding a heat-expandable compound by heat at the time of a fire, and a refractory material for a gas pipe.

Conventionally, various techniques for improving the fireproof performance of a refractory composition have been studied. For example, Patent Document 1 proposes a refractory composition capable of imparting excellent work efficiency to a refractory coating material obtained by molding a refractory composition.

Japanese Unexamined Patent Publication No. 2008-115359

The above-mentioned conventional refractory composition can be used without any problem when it is used by being attached to a steel frame or a wall, but since it has weak resistance to gas flowing through gas pipes, it should be used at the joint of those gas pipes. Was difficult. Therefore, there is a demand for a refractory composition that can be used at the joint of gas pipes.

As a result of diligent studies by the present inventor, if the difference between the solubility parameter of the fluid flowing through the gas pipe and the solubility parameter of the polymer contained in the fire-resistant composition is more than 1.0, the above problem can be solved. I found that there is. Specifically, it has been found that the above-mentioned problems can be solved when the solubility parameter of the polymer is more than 8.0, and the present invention has been completed.

According to the present invention, there is provided a refractory composition containing a polymer, a heat-expandable compound, and an inorganic filler, wherein the solubility parameter of the polymer is more than 8.0. To.

1. 1. Refractory Composition The refractory composition according to the present embodiment contains a polymer, a heat-expandable compound, and an inorganic filler. The refractory product may contain additives other than the above-mentioned components, if necessary. Examples of the additive include a lubricant, an antiaging agent, a reinforcing material filler such as a carbon book, a plasticizer, a processing aid, a vulcanizing agent, a vulcanization accelerator, and a vulcanization delaying agent.

(1) Polymer The polymer of the present invention has a solubility parameter of more than 8.0. The solubility parameter is also referred to as SP value (δ). In the present invention, the "solubility parameter" or "SP value (δ)" is a value determined based on the theory of Hildebrand's regular solution, and is a parameter that determines the activity of each component in a multi-component system. There are various calculation methods for the solubility parameter, but unless otherwise specified in the present specification, the solubility parameter is calculated by the Small method using the Hoy constant (Hoy, KL: J.Paint). Tech., 42, 76 (1970)).
That is, the solubility parameter δ [(cal / ml) ^1/2 ] is calculated by the following equation 1.
δ = d * (ΣG) / M (expression 1)
Here, d is the density [g / ml], G is the molecular attractiveness constant [(cal · ml) ^1/2 / mol] of each functional group of Hoy, and M is the molecular weight [g / mol].

Examples of polymers having an SP value range of more than 8.0 include chlorosulfonated polyethylene (SP value 8.1 to 9.8), chloroprene rubber (SP value 8.1 to 9.4), and nitrile rubber (SP value 8.1 to 9.4). SP value 8.7 to 10.5), polymethyl methacrylate (SP value 9.1 to 9.5), rubber polysulfide (SP value 9.0 to 9.4), rubber chloride (SP value 9.4) ), Polyvinyl acetate (SP value 9.4 to 9.6), acrylic rubber (SP value 9.5), polyvinyl chloride (SP value 9.4 to 10.8), urethane rubber (SP value 10.0) ), Polyethylene terephthalate (SP value 10.7), epoxy resin (SP value 10.9), phenol resin (SP value 11.3), polyvinyl chloride (SP value 12.2), polyvinyl alcohol (SP value 12. 6), polyamide (66-nylon) (SP value 13.6), cellulose (SP value 15.7) and the like. These polymers may be used alone or in combination of two or more.

When the refractory composition is used as a refractory material for a gas pipe, if the difference between the SP value of the polymer and the SP value of the gas flowing through the gas pipe is 1.0 or less, the fire resistant composition dissolves in the fluid flowing through the gas pipe. The problem of doing can occur. In particular, when the SP value of the polymer is 8.0 or less, the problem is likely to occur.

(2) Thermally expandable compound The thermally expandable compound is not particularly limited as long as it expands when heated, and examples thereof include vermiculite, kaolin, mica, and thermally expandable graphite. Among these, thermally expandable graphite is preferable because the expansion start temperature is low.

Heat-expandable graphite is a surface-treated graphite powder such as natural graphite or thermally decomposed graphite using an inorganic acid such as sulfuric acid or nitric acid and a strong oxidizing agent such as concentrated nitric acid or permanganate. It is a crystalline compound that maintains a graphite layered structure. When they are exposed to a temperature higher than the expansion start temperature (about 200 ° C.) under normal pressure, they thermally expand 100 times or more. The graphite powder such as natural graphite and pyrolytic graphite may be deoxidized, further neutralized, or the like.

The particle size of the heat-expandable graphite is preferably 20 to 400 mesh (measured by JIS Z 8901). This is because if the particle size of the heat-expandable graphite is larger than 400 mesh, the degree of expansion of the heat-expandable graphite becomes small, and the refractory composition may not be sufficiently thermally expanded in the event of a fire. Further, if the particle size of the heat-expandable graphite is smaller than 20 meshes, the dispersibility is reduced and the elasticity of the refractory composition may be lowered. In the present invention, the means for adjusting the heat-expandable graphite to a desired particle size is not particularly limited. For example, a crusher and a classifier can be used to obtain a desired particle size.

The content of the heat-expandable compound in the refractory composition of the present embodiment is preferably 10 to 500 parts by mass with respect to 100 parts by mass of the polymer. When the content of the heat-expandable compound is 10 parts by mass or more, sufficient thermal expandability is obtained, and when it is 500 parts by mass or less, sufficient shape retention after expansion is obtained.

(3) Inorganic filler The inorganic filler is particles of an inorganic substance. The shape of the particles is not particularly limited, and examples thereof include a spherical shape, an elliptical spherical shape, a cubic shape, a rectangular parallelepiped shape, and a random shape. The particles may be hollow or solid. Further, assuming that the length of the longest part of the particle is L and the diameter of the maximum circumscribed circle on the plane perpendicular to the longest part is D, the L / D is, for example, 1.0 to 10.0. , 1.0 to 5.0 is preferable.

The average particle size of the inorganic filler is, for example, 10 to 1000 μm, preferably 20 to 800 μm, more preferably 30 to 500 μm, still more preferably 40 to 200 μm. The "average particle size" means the particle size at an integrated value of 50% in the particle size distribution obtained by the laser diffraction / scattering method.

Examples of the inorganic filler include alumina, silica, aluminosilicate, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, aluminum phosphite, aluminum hydrogen phosphite, and aluminum hydroxide. , Metal oxides such as ferrites; Hydrous inorganic substances such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, hydrotalcite; basic magnesium carbonate, calcium carbonate, magnesium carbonate, zinc carbonate, strontium carbonate, barium carbonate, etc. Metallic carbonates; Calcium salts such as calcium sulfate and calcium silicate; diatomaceous soil, dosonite, barium sulfate, talc, clay, mica, montmorillonite, bentonite, active white clay, sepiolite, imogolite, sericite, glass beads, silica-based balun, nitride Aluminum, boron nitride, silicon nitride, carbon black, graphite, carbon balun, charcoal powder, various metal powders, potassium titanate, magnesium sulfate, ammonium polyphosphate, lead zirconate titanate, aluminum borate, molybdenum sulfide, silicon carbide , Zinc borate, various magnetic powders, fly ash, dehydrated sludge and the like.

The content of the inorganic filler in the refractory composition of the present embodiment is preferably 30 to 500 parts by mass with respect to 100 parts by mass of the polymer. When the content of the inorganic filler is 30 parts by mass or more, the flame retardancy of the refractory composition is sufficiently obtained, and when it is 500 parts by mass or less, the shape retention after expansion is sufficiently obtained.

From the viewpoint of shape retention, the inorganic filler preferably contains aluminum phosphite. The content of aluminum phosphite is preferably 10 to 300 parts by mass, more preferably 20 to 200 parts by mass, based on 100 parts by mass of the polymer.

(4) Softener The fire-resistant composition of the present embodiment preferably contains a softener. Examples of the softening agent include paraffin-based or naphthenic-based process oils, vegetable oils, paraffins such as liquid paraffin, waxes, phthalic acid, adipic acid, sebacic acid-based or phosphoric acid-based ester-based plasticizers, stearic acid or its esters. Examples include liquid rubbers such as polybutadiene, polyisoprene, and polybutene. Examples of vegetable oils include flaxseed oil, sesame oil, olive oil, grape sheet, corn oil, sesame oil, rice oil, soybean oil, rapeseed oil, palm oil, sunflower oil, beni flower oil, cottonseed oil, and peanut oil.

From the viewpoint of resistance to the gas flowing through the gas pipe, the softening agent contained in the refractory composition is preferably vegetable oil. When the polymer is chloroprene rubber, the softener is preferably rapeseed oil from the viewpoint of compatibility.

The content of the softening agent in the refractory composition is preferably 5 to 80 parts by mass with respect to 100 parts by mass of the polymer. When the content of the softener is 5 parts by mass or more, sufficient flexibility is obtained, and when it is 80 parts by mass or less, sufficient fluid resistance is obtained.

2. 2. Refractory material for gas pipes The refractory material for gas pipes of the present embodiment can be obtained by kneading the above-mentioned refractory composition, preforming the obtained compound into a desired shape, and performing a vulcanization treatment.

Examples of the device for kneading the refractory composition include a kneading device such as a mixer, a Banbury mixer, a kneader mixer, and a double roll. Examples of the apparatus for molding the kneaded refractory composition include molding apparatus for performing press molding, extrusion molding, calender molding and the like. Generally, the fire-resistant composition is extruded into a product shape by a rubber extruder, then introduced into a vulcanization tank, and vulcanized by heating by means such as hot air, a fluidized bed, or microwave. And foaming can be performed. The shape of the foam molded product is not particularly limited, and can be appropriately selected depending on the application, installation location, etc., such as a sheet shape or a tape shape.

The refractory material for gas pipes of the present embodiment is used at the joint of gas pipes and expands in the event of a fire to prevent gas leakage from the gas pipes. Specifically, the refractory material for gas pipes is installed inside a connecting tool (for example, a joint or a coupling) for connecting gas pipes, or is installed in a band shape along a joint between gas pipes. To do. Examples of the fluid flowing through the gas pipe include methane (SP value 5.4), ethane (SP value 6.0), propane (SP value 6.4), n-pentane (SP value 7.0), and the like. .. The fluid flowing through the gas pipe may be of one type or of a plurality of types. When a plurality of types of fluids flow, the fluids may flow simultaneously as a mixture or separately as a single substance.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but these Examples do not limit the present invention.

The following materials were used in Examples and Comparative Examples.
(1) Polymer-Chloroprene rubber ("S-40V" manufactured by Denka Co., Ltd.) SP value 8.3
-Acrylonitrile-butadiene rubber ("N250S" manufactured by JSR Corporation) SP value 9.4
-Ethylene-propylene-diene rubber ("4045H" manufactured by Mitsui Chemicals, Inc.) SP value 7.6
In Table 1, acrylonitrile-butadiene rubber is described as NBR, and ethylene-propylene-diene rubber is described as EPDM.
(2) Thermally expandable compound ・ Thermally expandable graphite (“SYZR9550250” manufactured by Sanyo Trading Co., Ltd.)
(3) Inorganic filler-Aluminum hydroxide ("C-301N" manufactured by Sumitomo Chemical Co., Ltd.)
-Aluminum phosphite ("APA-100" manufactured by Taihei Kagaku Sangyo Co., Ltd.
・ Calcium carbonate (Chichibu Petroleum Industry Co., Ltd. "Tancal TA-044")
・ Magnesium hydroxide (Kyowa Chemical Industry Co., Ltd. “Kisuma 5A”)
(4) Softener ・ Naphthenic oil ("Diana Process Oil NP-24" manufactured by Idemitsu Kosan Co., Ltd.)
・ Rapeseed oil (J-Oil Mills Co., Ltd. "Rapeseed white squeezed oil")
(5) Vulcanizing agent-Ethylene thiourea ("Axel 22S" manufactured by Kawaguchi Chemical Industry Co., Ltd.)
・ Sulfur (“Sulfur powder” manufactured by Hosoi Chemical Industry Co., Ltd.)

The components of the blending amounts (parts by mass) shown in Tables 1 to 3 are kneaded at a kneading temperature of 80 ° C. and a rotation speed of 40 using a pressurized kneader (Moriyama Co., Ltd./mixing capacity 3 liters / DS3-10MWB-S type). Kneading was carried out for 5 minutes under the condition of rotation / minute to obtain a refractory composition. The obtained refractory composition was formed into a sheet with an 8-inch roll, and then vulcanized using a press. Various physical properties of the obtained molded product were evaluated by the following procedure.

-Fluid resistance According to JIS K 7114: 2001, a sample (length 2 mm, width 2 mm, thickness 2 mm) is immersed in n-pentane (SP value 7.0), and the weight change rate after 72 hours is determined. It was measured. The smaller the rate of change in weight, the higher the fluid resistance.

-Flame retardant 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 larger the oxygen index, the higher the flame retardancy.

・ Thermal expansion
The volume expansion coefficient under combustion was measured as an index showing the thermal expandability. Specifically, the volume expansion ratio 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 larger the coefficient of thermal expansion, the better the thermal expansion property.

-Shape retention A test piece having a length of 30 mm, a width of 30 mm, and a thickness of 4 mm was prepared and dried at 110 ° C. for 24 hours. After the dried test piece was left in an atmosphere held at 600 ° C. for 0.5 hours, a 3-point bending test jig (upper push side tip R1 mm and width 80 mm, lower 2 point fulcrum side R1 mm and width 80 mm, between branches Fracture was performed under the condition of a compression speed of 50 mm / min using a distance of 20 mm), and the fracture strength at that time (three-point bending fracture strength) was measured. The greater the breaking strength, the higher the shape retention.

-Flexibility Punch the test piece from a refractory material with a thickness of 5 mm into the shape of a No. 1 dumbbell, gradually lift both ends of the test piece while holding the center of the test piece, and when the test piece cracks. The angle (the angle formed by the straight line connecting the center and one end and the straight line connecting the center and the other end) was measured. It should be noted that the larger the angle at which the crack is formed, the better the flexibility.

Since the SP value of the fluid flowing through the gas pipe is lower than the SP value of the polymer, the higher the SP value of the polymer, the more difficult it is for the polymer to dissolve in the fluid. In particular, when the SP value of the polymer exceeds 8.0, elution of the polymer is suppressed and gas leakage in the gas pipe is suppressed.

From the results of Examples 1 to 3, 25, and 26, it can be seen that when the blending amount of the heat-expandable compound is large, the heat-expandability tends to be improved and the shape retention tends to be lowered. In particular, when the amount of the heat-expandable compound is 10 parts by mass or more, sufficient thermal expansion property is obtained, and when the amount of the heat-expandable compound is 500 parts by mass or less, sufficient shape retention is obtained.

From the results of Examples 3 and 27 to 30, it can be seen that as the blending amount of the inorganic filler increases, the flame retardancy tends to improve and the shape retention tends to decrease. In particular, when the blending amount of the inorganic filler is 30 parts by mass or more, sufficient flame retardancy is obtained, and when the blending amount of the inorganic filler is 500 parts by mass or less, sufficient shape retention is obtained. Be done.

From the results of Examples 3, 14, 17 to 20, it can be seen that when the inorganic filler contains aluminum phosphite, the shape retention is excellent. Further, when the blending amount of aluminum phosphite is 20 parts by mass or more, sufficient flame retardancy can be obtained. When the blending amount of aluminum phosphite is 200 parts by mass or less, sufficient thermal expansion can be obtained.

From the results of Examples 3, 14 to 16, when the inorganic filler contains aluminum hydroxide or aluminum phosphite, the flame retardancy is higher than when the inorganic filler contains magnesium hydroxide or calcium carbonate. It turns out that it is excellent in sex.

From the results of Examples 3 to 13, it can be seen that when the refractory composition contains a softener, it is excellent in flexibility. In particular, when the blending amount of the softener is 5 parts by mass or more, sufficient flexibility can be obtained. When the blending amount of the softener is 80 parts by mass or less, sufficient flame retardancy can be obtained.

From the results of Examples 3, 31 to 33, it can be seen that the case where chloroprene rubber is used as the polymer is superior in flame retardancy and shape retention as the case where nitrile rubber is used. There was no significant difference in thermal expansion between the case where chloroprene rubber was used and the case where nitrile rubber was used.

Claims (6)

A refractory composition comprising a polymer, a thermally expandable compound, and an inorganic filler.
A refractory composition having a solubility parameter of the polymer of more than 8.0. The refractory composition according to claim 1.
A refractory composition containing 10 to 500 parts by mass of the heat-expandable compound and 30 to 500 parts by mass of the inorganic filler with respect to 100 parts by mass of the polymer. The refractory composition according to claim 1 or 2.
A refractory composition in which the polymer is chloroprene rubber or acrylonitrile-butadiene rubber (NBR). The refractory composition according to any one of claims 1 to 3.
A refractory composition further comprising a vulcanizing agent. A refractory material for gas pipes used at the joints of gas pipes.
A refractory material for a gas pipe, which is formed of the refractory composition according to any one of claims 1 to 4. The refractory material for gas pipes according to claim 5.
A refractory material for a gas pipe in which the difference between the solubility parameter of the fluid flowing through the gas pipe and the solubility parameter of the polymer is more than 1.0.