JP6510127B1 - Piping structure and method of manufacturing piping material - Google Patents

Abstract

An object of the present invention is to prevent deformation of a pipe joint in the event of a fire even though the thermal expansion start temperature of the piping material is high and it is easy to prepare the piping material, and the section penetration part can be closed reliably by the expansion of the piping material. Provide a piping structure. A piping structure 1 of the present invention includes a pipe joint 10 having a receiving port 11a and a piping material 20, and the receiving port 11a and the piping material 20 in a section penetration portion 2a of a floor slab 2 or a wall. The pipe joint 10 contains a resin composition (A) containing a polyvinyl chloride resin and an endothermic agent. The piping material 20 has a polyvinyl chloride resin and a thermal expansion start temperature of 240. It contains a resin composition (B) containing thermally expandable graphite having a temperature of at least ° C. [Selected figure] Figure 1

Description

  The present invention relates to a piping structure installed inside a building such as an apartment house.

In a building such as an apartment house, adjacent upper and lower floors are separated by floor slabs, and in each floor, two adjacent rooms are partitioned by walls and partitioned. A pipe structure for draining or supplying water is installed inside the building, and a through hole through which the pipe structure passes through the floor slab and the wall (herein, this through hole is referred to as a section through portion) Is formed.
As a piping structure passed through the section penetration part of the floor slab, for example, the first standing pipe (pipe material) installed vertically in the lower floor with respect to the floor slab and the floor slab A second vertical pipe (pipe material) vertically installed on the upper floor, a horizontal branch pipe (pipe material) installed on the upper side of the floor slab, and a socket for connecting the pipes are provided. One having a three-way pipe joint can be mentioned. In such a piping structure, the upper end portion of the first upright pipe is connected to the socket of the pipe joint in the section penetration portion formed in the floor slab. In addition, a sealing material such as mortar is filled between the inner surface of the section penetrating portion and the pipe joint, and the gap between the inner surface of the section penetrating portion and the pipe joint is filled.

When a fire occurs in a building where the above piping structure is installed, fire, heat and smoke rise from the floor where the fire is occurring to the floor above it through the section penetration part, causing physical damage And may increase personal injury. Therefore, in the case of a fire, in the case of a fire, the piping structure is usually provided with a fireproofing measure that shields light, shields heat, and shields smoke at the section penetration part.
As a measure against fire resistance in a piping structure, a method is known in which thermally expandable graphite is contained in a piping material inserted into a section penetration portion (Patent Document 1). When thermally expandable graphite is contained in the piping material, when a fire occurs and heat rises, the piping material can be expanded by the heat to close the section penetrating portion. As such, flame, heat and smoke can be prevented from rising through the compartment penetrations.

  By the way, when producing piping material, it is necessary to heat resin which forms piping material, and to fuse and shape it. However, if the thermal expansion start temperature of the thermally expandable graphite to be contained in the piping material is low, the thermally expandable graphite may expand during the preparation of the piping material, so it is difficult to manufacture the piping material. Therefore, as the thermally expandable graphite contained in the piping material, the thermal expansion start temperature is preferably a temperature higher than the heating temperature of the resin at the time of manufacturing the piping material, for example, 240 ° C. or more.

Patent No. 4829847

However, when the thermal expansion start temperature of the piping material is increased by incorporating the thermally expandable graphite having a high thermal expansion start temperature into the piping material, the thermal expansion start of the piping material is delayed when a fire occurs. There is a tendency. Therefore, it is conceivable that the pipe joint above the piping material is heated by the heat of the fire and is deformed or melted before the division penetration portion is closed by the expansion of the piping material. If the fitting is deformed, it is predicted that a gap will be generated between the filling material and the sealing material filled around the fitting. The gap may cause flames, heat and smoke to rise from the lower floor to the upper floor. When the pipe joint is melted, it becomes difficult to connect the piping material, and it is predicted that the piping material will fall and it will be difficult to close the section penetrating portion due to the expansion of the piping material.
In the present invention, although the thermal expansion start temperature of the piping material is high and it is easy to prepare the piping material, the deformation of the pipe joint can be suppressed when a fire occurs, and the division penetrating portion is reliably closed by the piping material expansion. An object of the present invention is to provide a piping structure that can

One aspect of the piping structure of the present invention comprises a pipe joint having a receiving port and a piping material, and a piping structure in which the receiving port and the piping material are connected in a section penetration portion of a floor slab or a wall The pipe joint contains a resin composition (A) containing a polyvinyl chloride resin and an endothermic agent, and the piping material has a polyvinyl chloride resin and a thermal expansion start temperature of 240 ° C. or higher. And a resin composition (B) containing thermally expandable graphite.
In the piping structure of this aspect, the content of the endothermic agent in the resin composition (A) is 0.01 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin. Is preferred.
In the piping structure of this aspect, the content of the thermally expandable graphite in the resin composition (B) is 10.0 parts by mass or more and 28.0 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin Is preferred.

  In the piping structure of the present invention, although the thermal expansion start temperature of the piping material is high and it is easy to prepare the piping material, the deformation of the pipe joint can be suppressed when a fire occurs, and the section penetration portion by the piping material expansion Can be closed securely.

It is a sectional view showing one embodiment of a piping structure of the present invention. It is a schematic block diagram which shows an example of the manufacturing apparatus which manufactures the piping material of 3 layer structure. It is sectional drawing which shows an example of the metal mold | die with which the manufacturing apparatus of FIG. 2 is equipped. It is a schematic diagram which shows an example of the vacuum sizing apparatus with which the manufacturing apparatus of FIG. 2 is equipped. (A) is a fragmentary sectional view which shows typically an example of the state of the end part of piping material (pipe) inserted in the socket of a pipe joint, (b) is piping inserted in the socket of a pipe joint It is a fragmentary sectional view showing typically another example of the state of the end of material (pipe). It is sectional drawing which shows a state when a fire generate | occur | produces in a building in the piping structure of FIG. It is sectional drawing which shows other embodiment of the piping structure of this invention. It is sectional drawing which shows the universal testing machine used by evaluation of the Example and the comparative example. It is sectional drawing which shows the fireproof test furnace used by evaluation of the Example and the comparative example.

One embodiment of a piping structure of the present invention will be described.
As shown in FIG. 1, the piping structure 1 of the present embodiment is used as a drainage channel, and includes a pipe joint 10 and a piping material 20. The piping structure 1 of the present embodiment is installed by passing through the section penetration portion 2a formed in the floor slab 2 that divides the adjacent upper and lower floors. The mortar 3 is filled between the piping structure 1 and the inner side surface of the section penetrating portion 2a, and the gap between the inner side surface of the section penetrating portion 2a and the pipe joint 10 is filled, and the piping structure I have fixed one.

(Pipe fitting)
The pipe joint 10 in the present embodiment includes a main pipe portion 11 and a horizontal branch pipe connection portion 12 provided to the main pipe portion 11.
On both ends of the main pipe portion 11, receptacles 11a and 11b for connecting a piping material 20 (a first upright pipe 21 and a second upright pipe 22 described later) are provided, and a horizontal branch pipe connecting portion At the end of the pipe 12, a socket 12a for connecting a piping material 20 (a pipe 23 for a horizontal branch pipe described later) is provided. The inner peripheral surface of the receiving port 11a is an inner diameter to which the outer peripheral surface of the piping material 20 (the first upright pipe 21) is in close contact, and the inner peripheral surface of the receiving port 11b is the piping material 20 (second upright) The inner diameter of the outer peripheral surface of the pipe pipe 22) is in close contact, and the inner peripheral surface of the socket 12a is the inner diameter of the outer peripheral surface of the piping member 20 (horizontal branch pipe 23).
In the present embodiment, the main pipe portion 11 is formed of a straight pipe. In order to make the flow of drainage flowing through the inside of the side branch pipe connecting portion 12 smooth, the vicinity of the main pipe portion 11 is curved toward the receiving port 11a.
A packing may be attached to the inner peripheral surface of each of the receptacles 11a, 11b, 12a so as to be in close contact with the outer peripheral surfaces of the pipes 21, 22, 23 to make it watertight.

The pipe joint 10 contains a resin composition (A) containing a polyvinyl chloride resin and an endothermic agent. That is, the pipe joint 10 is produced by molding the resin composition (A). Usually, the fitting 10 is produced by injection molding of the resin composition (A).
The pipe joint 10 may have a single layer structure in which the whole pipe joint 10 is made of the resin composition (A), or may have a multilayer structure consisting of a plurality of layers. In the case of a multilayer structure, any layer may be formed from the resin composition (A). For example, in the case where the pipe joint 10 has a three-layer structure including a surface layer, an intermediate layer, and an inner layer, the intermediate layer may be formed of the resin composition (A).
It is preferable that the resin composition (A) which comprises the pipe joint 10 does not contain thermally expansible graphite.

[Resin composition (A)]
Examples of polyvinyl chloride resins contained in the resin composition (A) include polyvinyl chloride homopolymers; vinyl chloride monomers and other monomers having an unsaturated bond copolymerizable with the vinyl chloride monomers. Copolymers: graft copolymers obtained by graft copolymerizing a vinyl chloride monomer to a polymer other than a polyvinyl chloride resin, and the like. The polyvinyl chloride resins may be used alone or in combination of two or more.
The polyvinyl chloride resin may be further chlorinated. As a chlorination method of polyvinyl chloride resin, a thermal chlorination method, a photochlorination method, etc. are mentioned, for example.

  Examples of other monomers having an unsaturated bond copolymerizable with the vinyl chloride monomer include α-olefins such as ethylene, propylene and butylene; vinyl esters such as vinyl acetate and vinyl propionate; butyl vinyl ether and cetyl Vinyl ethers such as vinyl ethers; (meth) acrylic esters such as methyl (meth) acrylate, ethyl (meth) acrylate and butyl acrylate; aromatic vinyls such as styrene and α-methylstyrene; N-phenylmaleimide, N- N-substituted maleimides, such as cyclohexyl maleimide, etc. are mentioned. The said other monomer may be used individually by 1 type, and may use 2 or more types together.

  As a polymer which graft-copolymerizes the said vinyl chloride monomer, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate-one, for example is mentioned. Examples include carbon monoxide copolymers, ethylene-methyl methacrylate copolymers, ethylene-propylene copolymers, acrylonitrile-butadiene copolymers, polyurethanes, chlorinated polyethylenes, chlorinated polypropylenes, and the like. One of these polymers may be used alone, or two or more thereof may be used in combination.

  The polyvinyl chloride resin may be crosslinked. Examples of the method of crosslinking the polyvinyl chloride resin include a method of adding a crosslinking agent and a peroxide, a method of irradiating an electron beam, and a method of using a water-crosslinkable material.

The average degree of polymerization of the polyvinyl chloride resin is preferably 400 or more and 1600 or less, and more preferably 600 or more and 1400 or less. Here, the average degree of polymerization is obtained by dissolving a polyvinyl chloride resin in tetrahydrofuran (THF) and removing insoluble components by filtration, and then using the resin obtained by drying and removing THF in the filtrate as a sample, JIS K- It is an average degree of polymerization measured according to 6721 "vinyl chloride resin test method".
If the average degree of polymerization of the polyvinyl chloride resin is at least the lower limit value, the mechanical strength can be sufficiently enhanced, and if it is at most the upper limit value, sufficient formability can be secured.

The endothermic agent contained in the resin composition (A) is a compound which has an endothermic effect when heated and suppresses the temperature rise. For example, a compound which causes an endothermic reaction such as a dehydration reaction when heated can be used as an endothermic agent.
Examples of compounds which cause a dehydration reaction when heated include magnesium hydroxide, aluminum hydroxide, inorganic minerals such as kaolinite (kaolinite, halloysite, dickite) and hydrotalsalcite, sepiolite, bentonite, The water-absorbing inorganic compounds such as montmorillonite, talc, mica, quartz, zeolite, wollastonite, nepheline sianite and the like can be mentioned. Hereinafter, inorganic hydroxides and inorganic compounds which cause a dehydration reaction when heated are generically referred to as "heated dehydration compounds". In the heat-dehydrating type compound, the temperature rise can also be suppressed by the latent heat of evaporation of water generated by the dehydration reaction.
Among the heat dewatering type compounds, magnesium hydroxide occurs at a temperature of 300 ° C. or higher. Therefore, when magnesium hydroxide is used as an endothermic agent, the resin composition (A) is molded to produce the pipe joint 10. It is possible to suppress the occurrence of dehydration reaction during the reaction.
Among the heat dewatering compounds, aluminum hydroxide causes dehydration reaction at about 200 ° C. Therefore, when aluminum hydroxide is used as an endothermic agent, the heat transmitted to the pipe joint 10 at the time of fire is absorbed early. be able to. Therefore, before the piping material 20 (the first upright pipe 21) thermally expands, it is possible to further suppress deformation of the pipe joint 10 and damage to the fire resistance.

Hydrotalcite is a kind of mineral represented by Mg ₆ Al ₂ (OH) ₁₆ CO ₃ · 4H ₂ O, etc., which has a chemical name of magnesium aluminum hydroxide oxide carbonate hydrate among heat-dehydrating compounds. There, positively charged basic layer _{[Mg 1-x Al x (} OH) 2] x + and a negatively charged intermediate layer _{[(CO 3) x / 2} · mH 2 O] x- inorganic compound having a layered consisting of is there. Many divalent and trivalent metals have the same layered structure, and these are represented by the following general formula.
[M ²⁺ _1−x M ³⁺ _x (OH) ₂ ] ^{x +} [A ^{n −} _{x / n} · _m H ₂ O] ^{x −}
M ²⁺ : divalent metal ion such as Mg ²⁺ , Zn ²⁺ M ³⁺ : trivalent metal ion such as Al ³⁺ , Fe ³⁺ etc. A ^{n −} : n-valent anion such as CO ₃ ²⁻ , Cl ⁻ , NO ₃ ⁻ X: 0 <X ≦ 0.33
Hydrotalcite starts to dehydrate from about 180 ° C. of water of crystallization between molecules, and the water of crystallization is completely eliminated at about 300 ° C. Although synthetic hydrotalcite retains the crystal structure up to this state, when the temperature exceeds about 350 ° C., the crystal structure begins to collapse and releases water and carbon dioxide. And, since synthetic hydrotalcite starts endothermic decomposition at a temperature lower by 60 ° C. or more and 75 ° C. or less than the thermal decomposition temperature of vinyl chloride resin at about 200 ° C. or more and 300 ° C. or less, the thermal decomposition of vinyl chloride resin The endothermic decomposition of hydrotalcite can be efficiently suppressed.
The endothermic agent may be used in combination of at least two of magnesium hydroxide, aluminum hydroxide, kaolin-based mineral and hydrotalcite.

The heat-dehydrating compound is usually in the form of particles.
The volume average particle diameter of the heat dehydrating compound is preferably 0.01 μm to 20 μm, more preferably 0.05 μm to 2 μm, and still more preferably 0.05 μm to 1 μm. By setting the volume average particle diameter of the heat dehydrating compound to this range, it is possible to impart transparency to the pipe fitting 10 and to improve the dispersibility of the heat dehydrating compound. The volume average particle size is a value measured using a laser diffraction scattering particle size distribution measuring apparatus.
The BET specific surface area of the heat dehydrating compound is preferably 1 m ² / g to 40 m ² / g, and more preferably 1 m ² / g to 20 m ² / g. Here, the BET specific surface area is a value obtained by using nitrogen adsorption.
If the volume average particle diameter and the BET specific surface area of the heat dewatering type compound are in the above ranges, the effect as the heat absorption agent can be sufficiently exhibited, and the moldability of the resin composition (A) in producing the pipe joint 10 And the mechanical physical property of the pipe joint 10 is fully securable.

The heat-dehydrating type compound is preferably surface-treated with a surface treatment agent such as a higher fatty acid such as stearic acid or a silane coupling agent. The heat-dehydration-type compound surface-treated with the surface treatment agent has high dispersibility in the polyvinyl chloride resin, and the endothermic effect can be more easily exhibited. In addition, when the heat-dehydration type compound is basic, the polyvinyl chloride-based resin is less likely to burn and yellowing can be prevented.
When the heat dehydrating type compound is surface-treated with a surface treating agent, the amount of the surface treating agent is preferably 0.05 parts by mass or more and 2.0 parts by mass or less with respect to 100 parts by mass of the heat dehydrating type compound. When the amount of the surface treatment agent is equal to or more than the lower limit value, the dispersibility of the heat-dehydration-type compound in the polyvinyl chloride resin can be sufficiently increased.

  The content of the endothermic agent in the resin composition (A) is preferably 0.01 parts by mass or more and 10.0 parts by mass or less, and more preferably 0.05 parts by mass or more, with respect to 100 parts by mass of the polyvinyl chloride resin. The content is more preferably not more than 0 parts by mass and still more preferably not less than 0.1 parts by mass and not more than 2.0 parts by mass. If the content of the endothermic agent in the resin composition (A) is above the lower limit value, deformation of the pipe joint 10 can be further suppressed when a fire occurs, and if below the above upper limit value, the pipe joint 10 is produced. At the same time, the formability of the pipe joint 10 can be sufficiently increased, and the mechanical properties of the pipe joint 10 can be improved.

The resin composition (A) may contain a flame retardant other than the endothermic agent, as long as the effects of the present invention are not impaired.
Other flame retardants include hydrotalcite, antimony dioxide, antimony trioxide, antimony oxide such as antimony pentoxide; molybdenum trioxide, molybdenum disulfide, molybdenum disulfide such as ammonium molybdate; tetrabromobisphenol A, tetrabromoethane Bromine compounds such as tetrabromoethane and tetrabromoethane; Phosphorus compounds such as triphenyl phosphate and ammonium polyphosphate; and Boric acid compounds such as calcium borate and zinc borate. Among the other flame retardants, antimony trioxide is preferable because of its high combustion suppressing effect on polyvinyl chloride.

Further, in the resin composition (A), a lubricant, a processing aid, an impact modifier, a heat resistance improver, an antioxidant, a heat stabilizer, a heat stabilization aid, to the extent that the effects of the present invention are not impaired Additives such as light stabilizers, UV absorbers, pigments, plasticizers, thermoplastic elastomers and the like may be included.
Each of the additives described later may be used alone or in combination of two or more.

The lubricants include internal lubricants and external lubricants.
Examples of internal lubricants include butyl stearate, lauryl alcohol, stearyl alcohol, epoxidized soybean oil, glycerin monostearate, stearic acid, bisamide and the like.
The external lubricant includes, for example, paraffin wax, polyolefin wax, ester wax, montan acid wax and the like.

  Examples of processing aids include alkyl acrylate-alkyl methacrylate copolymers having a weight average molecular weight of 100,000 or more and 2,000,000 or less. Examples of the alkyl acrylate-alkyl methacrylate copolymer include n-butyl acrylate-methyl methacrylate copolymer and 2-ethylhexyl acrylate-methyl methacrylate-butyl methacrylate copolymer.

Examples of impact modifiers include methyl methacrylate-butadiene-styrene copolymer (MBS), chlorinated polyethylene, acrylic rubber and the like.
Examples of the heat resistance improver include α-methylstyrene resins and N-phenylmaleimide resins.

  As an antioxidant, a phenol type antioxidant, phosphorus type antioxidant etc. are mentioned, for example.

Examples of the heat stabilizer include lead-based stabilizers, tin-based stabilizers, Ca-Zn-based stabilizers, and higher fatty acid metal salts. A heat stabilizer may be used individually by 1 type, and may use 2 or more types together.
Examples of lead-based stabilizers include lead white, basic lead sulfite, tribasic lead sulfate, dibasic lead phosphite, dibasic lead phthalate, tribasic lead maleate, silica gel coprecipitated silicic acid Examples thereof include lead, dibasic lead stearate, lead stearate and lead naphthenate.
Examples of tin-based stabilizers include mercaptides such as dibutyltin mercapto, dioctyltin mercapto and dimethyltin mercapto; malates such as dibutyltin malate, dibutyltin malate polymer, dioctyltin malate and dioctyltin malate polymer; dibutyl Examples include carboxylates such as tin mercaptodibutyltin laurate and dibutyltin laurate polymer.
The Ca-Zn stabilizer is a mixture of a fatty acid salt of calcium and a fatty acid salt of zinc. Examples of fatty acids include behenic acid, stearic acid, lauric acid, oleic acid, palmitic acid, ricinoleic acid, benzoic acid and the like, and two or more of these may be used in combination.
As a higher fatty acid metal salt, for example, lithium stearate, magnesium stearate, calcium stearate, calcium laurate, calcium ricinoleate, strontium stearate, barium stearate, barium laurate, barium ricinoleate, cadmium stearate, cadmium laurate , Cadmium ricinoleate, cadmium naphthenate, cadmium 2-ethylhexoate, zinc stearate, zinc laurate, zinc ricinoleate, zinc 2-ethylhexoate, lead stearate, lead dibasic stearate, lead naphthenate, etc. Be
Among them, tin-type stabilizers or Ca-Zn-type stabilizers are preferable when making the pipe joint 10 transparent, and as tin-type stabilizers, sulfur-free substances such as malates and carboxylates are polluted by sulfurization. In particular, a Ca--Zn-based stabilizer is preferably a stearate in view of the balance between lubricity and plate-out during molding.

  The content of the heat stabilizer is preferably 0.3 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin. If the content of the heat stabilizer is not less than the above lower limit, the heat stability of the polyvinyl chloride resin at the time of molding can be improved, and if it is not more than the above lower limit, the polyvinyl chloride resin at the time of combustion Can be carbonized sufficiently, and sufficient fire resistance performance can be obtained.

Examples of the heat stabilization aid include epoxidized soybean oil, phosphoric acid ester, polyol, hydrotalcite, zeolite and the like.
As a light stabilizer, a hindered amine light stabilizer etc. are mentioned, for example.
Examples of the ultraviolet absorber include salicylic acid ester-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and cyanoacrylate-based ultraviolet absorbers.

  Examples of the pigment include organic pigments such as azo pigments, phthalocyanine pigments, slen pigments, dye lakes, etc .; oxide pigments, molybdenum chromate pigments, sulfide / selenide pigments, ferrocyanide pigments And inorganic pigments such as

  Examples of the plasticizer include dibutyl phthalate, di-2-ethylhexyl phthalate, di-2-ethylhexyl adipate and the like. However, since the plasticizer tends to lower the heat resistance and the fire resistance of the molded article, the amount of the plasticizer used is preferably small.

  As a thermoplastic elastomer, for example, acrylonitrile-butadiene copolymer (NBR), ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl acetate-carbon monoxide copolymer (EVACO), vinyl chloride-vinyl acetate copolymer Polymers, vinyl chloride thermoplastic elastomers such as vinyl chloride-vinylidene chloride copolymer, styrene thermoplastic elastomers, olefin thermoplastic elastomers, urethane thermoplastic elastomers, polyester thermoplastic elastomers, polyamide thermoplastic elastomers, etc. Can be mentioned.

(Piping material)
The piping material 20 in the present embodiment is a first upright pipe 21, a second upright pipe 22 and a horizontal branch pipe 23.
The first upright pipe 21 is disposed vertically downward with respect to the floor slab 2, and the upper end portion of the first upright pipe 21 is connected to the lower socket 11 a of the pipe joint 10. The upper end portion of the first upright pipe 21 is inserted into the section penetrating portion 2a.
The second upright pipe 22 is vertically disposed upward with respect to the floor slab 2, and the lower end thereof is connected to the upper socket 11 b of the pipe joint 10.
One end of the horizontal branch pipe 23 is connected to the socket 12 a of the horizontal branch pipe connection 12, and the horizontal branch pipe 23 is inclined and disposed so as to be gradually higher as it is separated from the socket 12 a. However, since the installation space of the horizontal branch pipe 23 is limited, the inclination of the horizontal branch pipe 23 is a slight inclination angle, for example, an inclination angle of 10 ° or less with respect to the horizontal direction.

The piping material 20 contains a resin composition (B) containing a polyvinyl chloride resin and thermally expandable graphite. That is, the piping material 20 is produced by shape | molding a resin composition (B). Usually, the piping material 20 is produced by extruding the resin composition (B).
The piping material 20 may have a single-layer structure in which the entire piping material 20 is made of the resin composition (B), or may have a multilayer structure including a plurality of layers. In the case of a multilayer structure, any layer may be formed from the resin composition (B). For example, in the case where the piping material 20 has a three-layer structure including a surface layer, an intermediate layer, and an inner layer, the intermediate layer may be formed of the resin composition (B). You may contain the said endothermic agent.
The intermediate layer is black because it contains thermally expandable graphite. Therefore, it is preferable that the surface layer and the inner layer contain a coloring agent other than black so as to be distinguishable from the intermediate layer.
The thickness of the intermediate layer is, for example, preferably 1.8 mm or more and 7.6 mm or less, more preferably 2.0 mm or more and 6.0 mm or less, and more preferably 2.5 mm or more and 5 mm or less in the case of the nominal diameter 100 A (outer diameter 114 mm). More preferably, it is less than or equal to .0 mm. Moreover, 85% or less of the thickness of piping material is preferable, as for the thickness of an intermediate | middle layer, 60% or less is more preferable, and 50% or less is more preferable. If the thickness of the intermediate layer is in the above range, the fire resistance and the strength of the piping material itself can be compatible.
The thickness of the surface layer and the inner layer is preferably 0.3 mm or more and 3.0 mm or less, and more preferably 0.6 mm or more and 1.5 mm or less, for example, in the case of the nominal diameter 100 A (outer diameter 114 mm). If the thickness of the coating layer is 0.3 mm or more, the mechanical strength as a pipe can be sufficiently secured, and if it is 3.0 mm or less, the decrease in fire resistance can be suppressed.
Moreover, it is preferable that the piping material 20 is what satisfy | fills the performance of JISK6741.

[Resin composition (B)]
As polyvinyl chloride resin contained in a resin composition (B), the thing similar to polyvinyl chloride resin contained in a resin composition (A) can be used.
Moreover, various additives may be contained in the resin composition (B). The additive may be the same as the additive that may be contained in the resin composition (A).

The thermally expandable graphite contained in the resin composition (B) has a thermal expansion start temperature of 240 ° C. or more, preferably 250 ° C. or more, more preferably 260 ° C. or more. Here, the thermal expansion start temperature of the thermally expandable graphite is at least 1.1 times the volume before the start of the temperature increase when the thermally expandable graphite is heated at a temperature rising rate of 150 ° C. to 5 ° C./min. The temperature when expanded to The interval of the temperature for measuring the volume of the thermally expandable graphite is not particularly limited, and for example, the volume may be measured each time the temperature rises by 5 ° C.
The thermal expansion start temperature equal to or higher than the lower limit value is sufficiently higher than the molding temperature when the resin composition (B) is molded to produce the piping material 20. Therefore, when the thermal expansion start temperature of thermally expandable graphite is more than the said lower limit, when shape | molding a resin composition (B), it can prevent that thermally expandable graphite expand | swells.
On the other hand, the expansion start temperature of the thermally expandable graphite is preferably 400 ° C. or less, more preferably 350 ° C. or less. If the expansion start temperature of the thermally expandable graphite is equal to or less than the upper limit, the thermally expandable graphite can be easily manufactured industrially, and the pipe joint 10 is heated and deformed or melted before the thermally expandable graphite is expanded. Can be prevented.

The thermal expansion graphite preferably has a degree of expansion of at least 180 cm ³ / g at 1000 ° C., and more preferably at least 185 cm ³ / g. Here, the expansion degree at 1000 ° C. of thermally expandable graphite is the volume (cm ³ ) per unit mass (g) after holding the thermally expandable graphite at 1000 ° C. for 10 seconds.
If the degree of expansion of the thermally expandable graphite is equal to or more than the lower limit value, the expansion is sufficiently performed, so that the section penetration portion 2a can be more reliably closed in the case of a fire.
The thermal expansion graphite preferably has a degree of expansion at 1000 ° C. of 240 cm ³ / g or less from the viewpoint of facilitating the production of the thermal expansion graphite.

The thermally expandable graphite as described above is obtained by treating graphite powder with an inorganic acid and an oxidizing agent. By this treatment, a crystalline compound in which an inorganic acid is inserted between the layers of graphite can be obtained. A crystalline compound in which an inorganic acid is inserted between graphite layers has thermal expansion.
Examples of the graphite include natural scaly graphite, pyrolytic graphite, quiche graphite and the like.
Examples of the inorganic acid include concentrated sulfuric acid, nitric acid and selenic acid.
Examples of the oxidizing agent include concentrated nitric acid, perchloric acid, perchlorate, permanganate, bichromate, hydrogen peroxide and the like.
After the graphite powder is treated with the inorganic acid and the oxidizing agent, neutralization may be performed to reduce the acidity.

The thermally expandable graphite preferably has a pH adjusted to an acidic range, specifically, a pH of 1.0 to 7.0, and more preferably a pH adjusted to 1.5 to 4.0. preferable. When the pH of the thermally expandable graphite is adjusted to an acidic range, in particular, pH 4.0 or less, the carbonization reaction of the polyvinyl chloride resin can be promoted when a fire occurs, and the carbonized structure before the resin is burned To reduce the flammability. If the pH of the thermally expandable graphite is 1.5 or more, the corrosion of the device with which the thermally expandable graphite contacts can be prevented.
The method of adjusting the pH of the thermally expandable graphite is not particularly limited. For example, when manufacturing thermally expandable graphite, after processing the powder of graphite with an inorganic acid and an oxidizing agent, water washing and drying are repeated, and the method of adjusting pH of thermally expandable graphite is mentioned.

  The average particle diameter of the thermally expandable graphite is preferably 10 μm or more and 1000 μm or less, and more preferably 100 μm or more and 700 μm or less. Also, the average thickness is 100 μm or less.

The average aspect ratio of the thermally expandable graphite is 30 or less, preferably 28 or less, more preferably 26 or less, and still more preferably 20 or less. When the average aspect ratio of the thermally expandable graphite is 30 or less, when the piping material has a multilayer structure, the difference in linear expansion coefficient between the layer containing thermally expandable graphite and the layer not containing it can be reduced. Defects in molding such as peeling of the middle layer and the surface layer due to the influence of cleaning of the inside of the piping material and heat contraction difference of high temperature drainage, etc. and the difference of contraction of the surface layer and the middle layer after molding becomes large and the piping material is warped Can be suppressed.
The linear expansion coefficient of the rigid polyvinyl chloride resin that constitutes the piping material is 7.0 × 10 ^-5 / ° C as measured by the thermomechanical analysis method (TMA method) specified by JIS K 7197. The piping material of the present embodiment is 4.5 × 10 ⁻⁵ / ° C. or more and 7.0 × 10 ⁻⁵ / ° C. or less, and 5.0 × 10 ⁻⁵ / ° C. or more 7.0 × 10 ⁻⁵ / ° C. Less than ° C is preferable, and 5.5 × 10 ⁻⁵ / ° C. or more and less than 6.8 × 10 ⁻⁵ / ° C. are more preferable. Further, the difference in linear expansion coefficient between the surface layer and the inner layer and the intermediate layer is 2.5 × 10 ⁻⁵ / ° C. or less, preferably 2.0 × 10 ⁻⁵ / ° C. or less, 1.0 × 10 ⁻⁵ / ° C. C. or less is more preferable.
Furthermore, the fusion bonding strength between the surface layer and the inner layer of the piping material and the intermediate layer is 0.8 MPa or more, preferably 1.0 MPa or more, more preferably 1.5 MPa or more, and still more preferably 2.0 MPa or more.

  The average aspect ratio is the ratio of the average diameter in the horizontal direction to the thickness in the vertical direction. Since the thermally expandable graphite used in the present invention is generally flat, it can be seen that the vertical direction corresponds to the thickness direction and the horizontal direction corresponds to the radial direction, so the maximum horizontal dimension is the thickness in the vertical direction. The divided value is taken as the aspect ratio.

  Then, the aspect ratio is measured for a sufficiently large number, ie, 10 or more pieces of graphite, and the average value thereof is taken as the average aspect ratio. The average particle diameter of the thermally expandable graphite can also be determined as the average value of the maximum dimension in the horizontal direction.

  The maximum dimension in the horizontal direction of thermally expandable graphite and the thickness of exfoliated graphite can be measured, for example, using a field emission scanning electron microscope (FE-SEM).

  When using a thermally expandable graphite having a pH adjusted to 1.5 or more and 4.0 or less, it is preferable to use a heat stabilizer in combination. Examples of the heat stabilizer include lead-based stabilizers, tin-based stabilizers, Ca-Zn-based stabilizers, and higher fatty acid metal salts. A heat stabilizer may be used individually by 1 type, and may use 2 or more types together.

Examples of lead-based stabilizers include lead white, basic lead sulfite, tribasic lead sulfate, dibasic lead phosphite, dibasic lead phthalate, tribasic lead maleate, silica gel coprecipitated silicic acid Examples thereof include lead, dibasic lead stearate, lead stearate and lead naphthenate.
Examples of tin-based stabilizers include mercaptides such as dibutyltin mercapto, dioctyltin mercapto and dimethyltin mercapto; malates such as dibutyltin malate, dibutyltin malate polymer, dioctyltin malate and dioctyltin malate polymer; dibutyl Examples include carboxylates such as tin mercaptodibutyltin laurate and dibutyltin laurate polymer.
The Ca-Zn stabilizer is a mixture of a fatty acid salt of calcium and a fatty acid salt of zinc. Examples of fatty acids include behenic acid, stearic acid, lauric acid, oleic acid, palmitic acid, ricinoleic acid, benzoic acid and the like, and two or more of these may be used in combination.
As a higher fatty acid metal salt, for example, lithium stearate, magnesium stearate, calcium stearate, calcium laurate, calcium ricinoleate, strontium stearate, barium stearate, barium laurate, barium ricinoleate, cadmium stearate, cadmium laurate , Cadmium ricinoleate, cadmium naphthenate, cadmium 2-ethylhexoate, zinc stearate, zinc laurate, zinc ricinoleate, zinc 2-ethylhexoate, lead stearate, lead dibasic stearate, lead naphthenate, etc. Be

  The content of the heat stabilizer is preferably 0.3 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin. If the content of the heat stabilizer is not less than the above lower limit, the heat stability of the polyvinyl chloride resin at the time of molding can be improved, and if it is not more than the above lower limit, the polyvinyl chloride resin at the time of combustion Can be carbonized sufficiently, and sufficient fire resistance performance can be obtained.

  In addition to the thermally expandable graphite, the resin composition (B) may contain the above-mentioned heat dehydration compound such as magnesium hydroxide or aluminum hydroxide, and the heat dehydration compound is contained. In addition, the fire resistance performance of the piping member 20 can be further improved. It is preferable that content of the said heat-dehydration type compound is 0.1 mass part or more and 20.0 mass parts or less with respect to 100 mass parts of polyvinyl chloride type-resin, 0.2 mass part or more and 5.0 mass parts It is more preferable that it is the following, and it is more preferable that it is 0.3 to 3.0 mass parts. If the content of the heat dehydrating compound is equal to or more than the lower limit, the fire resistance can be further enhanced, and if the content is equal to or less than the upper limit, the mechanical strength of the piping material 20 can be sufficiently high. .

In addition to the thermally expandable graphite, the resin composition (B) preferably contains an inorganic filler.
As the inorganic filler, inorganic compounds other than the above-mentioned endothermic agent, such as silica, diatomaceous earth, alumina, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, ferrites, calcium hydroxide Basic magnesium carbonate, calcium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, dononite, hydrotalcite, calcium sulfate, barium sulfate, gypsum fiber, calcium silicate, talc, clay, mica, montmorillonite, bentonite, activated 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, matric acid sulfate Neshiumu, lead zirconate titanate, aluminum borate, molybdenum sulfide, silicon carbide, stainless steel fiber, zinc phosphate, zinc borate, various magnetic powder, slag fibers, fly ash, and a dewatered sludge. Among the above-mentioned inorganic fillers, basic inorganic fillers such as calcium carbonate, calcium silicate, calcium hydroxide, calcium oxide, magnesium carbonate, magnesium oxide, barium carbonate, zinc oxide, zinc hydroxide and iron oxide are preferable.
The said inorganic filler may be used individually by 1 type, and may use 2 or more types together.

The content of the inorganic filler is preferably 0.3 parts by mass or more and 50.0 parts by mass or less, and is 1.0 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin It is more preferable that If the content of the inorganic filler is equal to or more than the lower limit, the fire resistance can be further enhanced, and if the content is equal to or less than the upper limit, the mechanical strength of the piping material 20 can be sufficiently high.
In particular, when using a thermally expandable graphite whose pH is adjusted to 1.5 or more and 4.0 or less, in the resin composition (B), the basic inorganic filler is a polyvinyl chloride resin. It is preferable to be contained in the ratio of 0.3 to 5.0 parts by mass with respect to 100 parts by mass. If the content ratio of the basic inorganic filler is equal to or more than the above lower limit, the thermal stability for forming the piping material 20 by molding the resin composition (B) becomes high, and the generation of carbide during molding can be prevented, If it is below the upper limit value, polyvinyl chloride resin at the time of fire occurrence can be fully carbonized, and fire resistance can be further improved.

  The content of the thermally expandable graphite in the resin composition (B) is preferably 10.0 parts by mass or more and 28.0 parts by mass or less, and 15.0 parts by mass with respect to 100 parts by mass of the polyvinyl chloride resin. The content is more preferably 26.0 parts by mass or less and still more preferably 18.0 parts by mass or more and 24.0 parts by mass or less. If the content of the thermally expandable graphite in the resin composition (B) is equal to or more than the lower limit value, the piping material 20 (particularly, the first upright pipe 21) can be sufficiently expanded when a fire occurs. The fire resistance of the section penetration portion 2a can be further improved. On the other hand, if the content of the thermally expandable graphite in the resin composition (B) is equal to or less than the upper limit value, the piping material 20 can be prevented from being broken by excessive expansion of the piping material 20 and fire resistance being lowered. .

[Method of manufacturing piping material]
A piping material having a three-layer structure including a surface layer, an intermediate layer, and an inner layer is manufactured using, for example, a manufacturing apparatus 60 shown in FIG.
The manufacturing apparatus 60 in this example includes a first extrusion molding machine 61, a second extrusion molding machine 62, a vacuum sizing apparatus 63, a pulling machine 64, and a cutting machine 65.

  The first extruder 61 includes a first extruder 68 for kneading, heating, melting and extruding the resin composition supplied from the hopper 66. The second extruder 62 includes a second extruder 69 for kneading, heating, melting and extruding the resin composition supplied from the hopper 67. A mold 70 is attached to the outlets of the first extruder 68 and the second extruder 69. The resin composition (B-2) constituting the surface layer and the inner layer of the piping material is supplied to the hopper 66 of the first extrusion molding machine 61. The resin composition (B-1) which comprises an intermediate | middle layer is supplied to the hopper 67 of the 2nd extrusion molding machine 62. As shown in FIG. It is preferable that at least the resin composition (B-1) contains a polyvinyl chloride resin and thermally expandable graphite. That is, it is preferable to use the resin composition (B) mentioned above as a resin composition (B-1).

  As shown in FIG. 3, the mold 70 is a three-layer extrusion mold and includes a joining portion 71 and a forming portion 72. In the joining portion 71, the molten resin (melted resin composition (B-2)) 73 introduced from the first extruder 68 and the molten resin introduced from the second extruder 69 (melted resin composition (B -1)) 74 merges, and these are stacked near the exit of the merging section 71. The laminated molten resins 73 and 74 are expanded in diameter in a state of being laminated in the molding section 72 and become tubular. The outer periphery and the inner periphery are restricted to a certain size by the die ring 75 and the mandrel 76 provided at the tip of the forming portion 72, and a continuous piping material (hereinafter referred to as "continuous tube") 77 is provided. It is pushed out.

At this time, it is preferable that the mold 70 be adjusted so that the molding temperature (the resin temperature at the time of molding) is 175 ° C. or more and less than 240 ° C. The molding temperature is more preferably 180 ° C. or more and 235 ° C. or less, still more preferably 185 ° C. or more and 230 ° C. or less, and particularly preferably 190 ° C. or more and 225 ° C. or less. By setting the molding temperature within the above range, the adhesion between the surface layer and the inner layer can be improved between the intermediate layer containing the thermally expandable graphite in a well-kneaded state.
When the molding temperature is less than 170 ° C., the kneading state of the resin composition (B-1) containing thermally expandable graphite is poor, and the fluidity in the mold 70 is reduced, which makes molding difficult. When the molding temperature exceeds 240 ° C., the thermally expandable tensile graphite contained in the resin composition (B-1) in the mold 70 expands.

The molding temperature is preferably adjusted so that the temperature gradually increases from the first and second extruders 61 and 62 to the mold 70. Specifically, the resin temperature at the connection portion between the first extruder 68 and the second extruder 69 and the mold 70 is set higher than the resin temperature of a general piping material, and is 150 ° C. or more and the mold temperature or less. Preferably, the temperature is 170 ° C. or more and the mold temperature or less is more preferable. The resin temperatures in the first extruder 68 and the second extruder 69 may be the same or may be different from each other. By making the resin temperature in the second extruder 62 for kneading the resin composition (B-1) containing thermally expandable graphite higher than the resin temperature in the first extruder 61, the fluidity of the resin is enhanced. Thus, the resin can be easily supplied to the merging portion 71 of the mold 70.
If the resin temperature in the first extruder 68 and the resin temperature in the second extruder 69 are different, a large amount of heat stabilizer should be blended in the resin with the higher temperature for the improvement of the thermal stability. Is preferred.

  Next, the continuous pipe 77 extruded from the mold 70 is introduced into the vacuum sizing device 63. The vacuum sizing device 63 is for shaping and cooling the outer surface of the continuous tube 77. As shown in FIG. 4, the vacuum sizing device 63 comprises a body 78 extending in the extrusion direction of the continuous tube 77. An inlet 79 and an outlet 80 of the main body 78 are formed at one end and the other end of the main body 78 in the longitudinal direction. A vacuum chamber 82 to which a vacuum pump 81 is connected is provided on the side of the inlet 79 in the main body 78. A sizing sleeve 83 is disposed in the vacuum chamber 82. One end of the sizing sleeve 83 is connected to the inlet 79. In addition, a cooling chamber 84 is provided between the vacuum chamber 82 and the outlet 80, and a water pipe 85 is disposed over the entire length of the vacuum chamber 82 and the cooling chamber 84.

When the continuous tube 77 is supplied to the vacuum sizing device 63, the negative pressure of the vacuum pump 81 causes the continuous tube 77 to expand and the outer surface thereof is in close contact with the inner surface of the sizing sleeve 83. The surface layer and the inner layer are in close contact with the intermediate layer. In addition, the sized continuous pipe 77 is cooled and hardened by the cooling water sprayed from the water spray pipe 85.
Note that, instead of the vacuum sizing device 63, a cooling water tank in which cooling water is stored may be used, and an inlet provided with a sizing sleeve can be used at the inlet of the cooling water tank.

  The puller 64 is for picking up the continuous pipe 77 at a constant speed. The puller 64 includes a plurality of pull rollers 86 pressed to the lower and upper portions of the continuous pipe 77. A motor (not shown) is connected to at least one of the take-off rollers 86, and the take-up speed of the continuous pipe 77 is adjusted by controlling the number of revolutions of the motor.

  The cutter 65 is for cutting the continuous pipe 77 into a predetermined length. The cutter 65 includes a sensor 87 for detecting the tip position of the continuous tube 77, and a cutting blade 88 driven in conjunction with the sensor 87. When the tip of the continuous pipe 77 pushes the sensor 87, the cutting blade 88 is driven to cut the continuous pipe 77, and a piping material having a predetermined length is obtained.

(Installation example and effect of piping structure)
In the piping structure 1 of the present embodiment, one receiving port 11a of the main pipe portion 11 constituting the pipe joint 10 is disposed inside the section penetrating portion 2a, and the first upright pipe 21 is disposed in the receiving port 11a. The upper end of the is connected.
Moreover, in the piping structure 1 of the present embodiment, the other receiving port 11b of the main pipe section 11 is disposed outside the section penetrating section 2a and above the floor slab 2, and the receiving port 11b is used for the second upright pipe The lower end of the pipe 22 is connected. Moreover, the receptacle 12a of the horizontal branch pipe connection part 12 is arrange | positioned on the upper part of the floor slab 2 the exterior of the division penetration part 2a, and the end part of the pipe 23 for horizontal branch pipes is connected to the receptacle 12a.
The connection method of each socket 11a, 11b, 12a and each pipe 21, 22, 23 is not particularly limited, and a known method can be appropriately applied, and the outer surface of each pipe and the packing provided inside each socket and The gap between the inner surface of each socket and the inner surface of each socket may be sealed, or an adhesive may be applied to the outer surface of each pipe to connect the inner surface of each socket and the outer surface of each pipe. In the case of bonding using an adhesive, as the adhesive, a colored adhesive to which a coloring agent is added, or an adhesive to which a light emitting agent which emits fluorescence or phosphorescence by ultraviolet light can be used. However, it is necessary to connect the receiving port 11a located inside the section penetrating portion 2a and the pipe 21 with an adhesive so as not to drop out of the receiving port 11a even when the pipe 21 is heated and thermally expanded.
The outer surface of the end of each of the pipes 21, 22, 23 inserted into the respective sockets 11a, 11b, 12a of the pipe joint 10 is a tapered surface over the entire circumference. The tapered surface referred to here may be a shape in which the end 20a of the piping member 20 along the pipe axis is cut off in a straight line as shown in FIG. 5A, for example. Further, the end 20a of the piping member 20 may be cut in an arc as shown in FIG. 5 (b), for example. 5A and 5B are partial cross-sectional views of the end portion 20a of the piping material 20 having a three-layer structure of the inner layer 26, the intermediate layer 27, and the surface layer 28. FIG.
When pipes 22, 22, and 23 have a three-layer structure of an inner layer, an intermediate layer, and a surface layer and the intermediate layer is formed of the resin composition (B), when inserting pipes 21, 22, and 23 into pipe joint 10, The surface layer may be cut until the layer is exposed, or it may be cut to such an extent that the intermediate layer is not exposed. If the middle layer is exposed, when the pipe joint 10 is transparent, the middle layer of the end face of the exposed piping material 20 is black, so the position of the end face can be visually recognized from the outside, and it is inserted to the back of the receptacle You can see it. In particular, when the joint is transparent, the packing provided at the receiving port can be visually recognized from the outside, so it can be determined whether the end of the piping member 20 is inserted by a predetermined length than the packing. If the intermediate layer is not exposed, the adhesive component does not penetrate into the intermediate layer or the interface between the intermediate layer and the surface layer, and the adhesive component prevents the interfacial peeling or cracking of the surface layer and the intermediate layer, etc. The thermally expandable graphite can prevent deterioration of the adhesive component.

As described above, the piping material 20 used in the piping structure 1 of the present embodiment contains thermally expandable graphite that expands when it is heated due to a fire. Therefore, for example, as shown in FIG. 6, when a fire occurs on the floor lower than the floor slab 2, the heat in the fire causes the portion in the section penetration portion 2a of the first standing pipe 21 to expand. Thus, the section penetration portion 2a can be closed. Thereby, it is possible to prevent fire, heat and smoke from rising to the floor above the floor slab 2 through the compartment penetration part 2a, so that fire resistance can be exhibited.
The thermally expandable graphite used in the present embodiment has a thermal expansion start temperature of 240 ° C. or higher, which is higher than a molding temperature (140 ° C. or more and less than 240 ° C.) when producing a piping material. Therefore, when producing the piping material 20, expansion of the thermally expandable graphite is prevented. Therefore, the piping material 20 in this embodiment is easy to produce.
In particular, when producing a piping material having a three-layer structure including a surface layer, an intermediate layer containing thermally expandable graphite, and an inner layer, the molding temperature (resin temperature at molding) is preferably 175 ° C. or more and less than 240 ° C. 180 ° C. or more and 235 ° C. or less is more preferable, 185 ° C. or more and 230 ° C. or less is more preferable, and 190 ° C. or more and 225 ° C. or less is particularly preferable. By setting the molding temperature within the above range, the adhesion between the surface layer and the inner layer can be improved between the intermediate layer containing the thermally expandable graphite in a well-kneaded state.
In addition, by raising the molding temperature, the fluidity of the resin can be enhanced, and even a resin containing thermally expandable graphite can be easily kneaded, merged, extruded, and the moldability can be improved.

When the thermal expansion start temperature of the thermally expandable graphite contained in the piping material 20 is high, when a fire occurs, the heat of the fire is pipe joint 10 before the piping material 20 thermally expands and blocks the section penetration part 2a. As a result, the pipe joint 10 may be deformed or melted to reduce the fire resistance. However, since the heat absorbing agent is contained in the pipe joint 10 constituting the piping structure 1 of the present embodiment, even if a fire occurs on the floor below the floor slab 2 and heat is transmitted to the pipe joint 10 An endothermic agent can absorb heat. Therefore, it is possible to delay the melting and deformation of the pipe joint 10. As a result, before the pipe joint 10 is melted and deformed, the first upright pipe 21 can be surely thermally expanded to close the section penetrating portion 2a, and the fire resistance can be sufficiently exhibited.
Therefore, according to the piping structure 1 of the present embodiment, although the thermal expansion start temperature of the piping material 20 is high and it is easy to manufacture the piping material 20, the piping material 20 thermally expands when a fire occurs. The deformation of the pipe joint 10 before can be suppressed, and the section penetration portion 2a can be reliably closed. Therefore, the piping structure 1 of this embodiment is excellent in the fire resistance of the division penetration part 2a.

In a building, a floor material 4 of a living part is usually installed above a floor slab 2 that divides adjacent upper and lower floors. A space S is formed between the floor slab 2 and the floor material 4, and a horizontal branch pipe 23 is disposed in the space S. Therefore, although the installation space for the horizontal branch pipe 23 is limited, normally, the horizontal branch pipe 23 becomes gradually higher as it is separated from the receiving port 12 a of the horizontal branch pipe connection portion 12 in order to enhance drainage. It is inclined to Under such circumstances, in the pipe joint 10, the horizontal branch pipe connection portion 12 is as close as possible to the floor slab 2 to lower the connection position of the horizontal branch pipe 23 as much as possible, and the horizontal branch in the space S It is required to increase the degree of freedom in the arrangement of the pipe 23 for pipe. In particular, when the building is a multi-dwelling house and there are a large number of rooms on the same floor, the horizontal branch pipe 23 becomes long. In that case, in the horizontal branch pipe 23, the horizontal branch pipe connection 12 side and The position of the opposite end will be high. Therefore, it is required to use the space between the floor slab 2 and the floor material 4 as effectively as possible. From this, in the pipe joint 10, the main pipe portion 11 is inserted as deep as possible into the section penetration portion 2a, and the horizontal branch pipe connection portion 12 is made close to the floor slab 2, and at the lower position as much as possible. It is preferable to connect the pipe 23. Further, it is preferable that at least the upper end of the receiving port 11 a does not exceed the upper surface of the floor slab 2, that is, the upper end of the upright pipe 21 does not exceed the upper surface of the floor slab 2.
When the insertion of the main pipe portion 11 into the section penetration portion 2a is made deeper, the lower receiving port 11a of the pipe joint 10 approaches the lower floor. In the present embodiment, the main pipe portion 11 is inserted into the section penetrating portion 2 a until the lower surface of the receiving port 11 a is flush with the lower surface of the floor slab 2.
If the lower socket 11a of the pipe joint 10 is close to the lower floor, the pipe joint 10 will be rapidly exposed to flames and heat when a fire occurs on the lower floor. Further, the length of the upright pipe 21 in which the thermally expandable graphite is blended in the section penetration portion 2a is short, and the closed length by the expanded pipe 21 is short. However, even in such a case, in the embodiment using the pipe joint 10 containing the heat absorbing agent, since the temperature rise of the pipe joint 10 can be delayed, the deformation of the pipe joint 10 can be suppressed. Furthermore, in the present embodiment, since the compounding amount of the thermally expandable graphite is sufficiently large, the section penetrating portion 2a can be sufficiently closed even if the closing length of the section penetrating portion 2a is short.
Therefore, according to the present embodiment, the fire resistance of the section penetrating portion 2a can be secured while increasing the degree of freedom of the arrangement of the horizontal branch pipe 23 in the space S between the floor slab 2 and the floor material 4.

(Other embodiments)
The present invention is not limited to the above embodiment.
For example, in the present invention, it is not necessary to connect the pipe joint and the upper end of the first standing pipe while the lower surface of the lower socket of the pipe joint is flush with the lower surface of the floor slab. . That is, the socket on the lower side of the pipe joint and the upper end portion of the first upright pipe may be connected at any portion in the section penetration portion.
In the present invention, the pipe joint is not limited to the three-way pipe joint having the shape described in the above embodiment, but may be a T-shaped pipe in which the horizontal branch pipe connection portion is provided vertically to the main pipe portion of the pipe joint. . Also, the pipe joint may connect two vertical pipes and two or more horizontal branch pipes, or connect one vertical pipe and two or more horizontal branch pipes. May be.
In the piping material, it is sufficient that at least the vertical pipe is composed of the resin composition (B), and the horizontal branch pipe includes a resin composition other than the resin composition (B), that is, thermally expandable graphite. There may be no resin composition.
Moreover, in the present invention, the piping material may have a receiving port at one end. In this case, the pipe joint is configured to have a port that is inserted into the port of the pipe, and the pipe port is formed by inserting and connecting the port of the pipe into the port of the pipe.
Moreover, the piping structure of this invention may be passed through the division penetration part formed in the wall. In the case where the piping structure is to be passed through the section penetration portion formed in the wall, the pipe joint may be provided with two receiving ports, or three or more receiving ports are provided. It may be something.
Moreover, the piping structure of this invention can be used also for a water supply path.

  Furthermore, in the above embodiment, the fire resistance is imparted by adding the heat dehydrating type compound to the resin composition (A), but the present invention is not limited to this, and the fire resistance is imparted by adding non-thermal expansion graphite. You may As the non-thermal expansion graphite, those described in Japanese Patent No. 4829847 can be used, and semitransparent or transparent by using non-thermal expansion graphite having a particle diameter of 10 μm to 1000 μm, preferably 10 μm to 100 μm. Coupling can be used.

Furthermore, the piping structure of the present invention may be in a state in which the piping material and the pipe joint are joined in advance by an adhesive at a factory or the like.
The piping structure 1 in this case includes, for example, an upper pipe joint 10a, a lower pipe joint 10b, and a pipe material 20, as shown in FIG.
The upper pipe joint 10a can connect the receiving port 13a to which the piping member 20 can be connected, the receiving port 11b to which the second upright pipe 122 extending from the upper floor can be connected, and the horizontal branch pipe 123 extending from the upper floor And the receptacle 12a.
The lower pipe joint 10b includes a port 13b to which the pipe member 20 can be connected, and a port 11a to which the first upright pipe 121 extending from the lower floor can be connected.
The upper end of the piping member 20 is connected to the socket 13 a of the upper pipe joint 10 a. The lower end of the piping member 20 is connected to the receiving port 13b of the lower pipe joint 10b.
The upper fitting 10a and the lower fitting 10b are made of the resin composition (A). The piping material 20 is composed of the resin composition (B). The first upright pipe 121, the second upright pipe 122, and the horizontal branch pipe 123 may be made of the resin composition (A) or be made of the resin composition (B). You may be comprised with materials other than the said resin composition (A) and the said resin composition (B).
The piping structure 1 shown in FIG. 7 is installed in a building so that the piping material 20 is disposed in the section penetration portion 2 a of the floor slab 2. In addition, mortar 3 is filled between the piping structure 1 and the inner side surface of the section penetrating portion 2a, and the gap between the inner side surface of the section penetrating portion 2a and the piping material 20 is filled and the piping structure The body 1 is fixed.

  In the piping structure 1 shown in FIG. 7, the port 13 a of the upper pipe joint 10 a and the pipe member 20 are connected in the section penetration portion 2 a of the floor slab 2, but the port 13 b of the lower pipe joint 10 b and pipe The material 20 may be connected within the section penetration portion 2 a of the floor slab 2. Further, the receiving port 13a of the upper pipe joint 10a may be connected to the pipe member 20, and the port 13b of the lower pipe joint 10b may be connected to the pipe material 20 in the section penetrating portion 2a of the floor slab 2.

  Hereinafter, the present invention will be described in more detail by way of examples and comparative examples, but the present invention is not limited to the following examples.

Example 1
100 parts by mass of polyvinyl chloride resin (TH700, manufactured by Taiyo Chloride Co., Ltd.), magnesium hydroxide as an endothermic agent (manufactured by Kyowa Chemical Industry Co., Ltd., Kisuma 5A, volume average particle diameter: 0.9 μm, BET specific surface area: 4 .8 m ² / g) 1 part by mass, ² parts by mass of a tin-based stabilizer (manufactured by Nitto Kasei Co., Ltd., AT-6300), and 0.5 parts by mass of a polyethylene-based lubricant (manufactured by Mitsui Chemicals, Inc., Hi-Wax 4202E) After compounding, a resin composition (A-1) was obtained by stirring and mixing using a Henschel mixer (manufactured by Kawada Kogyo Co., Ltd.) having an inner volume of 200 liters.
The resin composition (A-1) was injection molded at a molding temperature of 190 ° C. using an injection molding machine to produce a pipe joint having the same shape as that of the above embodiment.

The piping material was composed of a surface layer, an intermediate layer and an inner layer.
The resin composition which comprises an intermediate | middle layer was obtained as follows.
100 parts by mass of polyvinyl chloride resin (TH1000, manufactured by Taiyo PVC Co., Ltd.), thermally expandable graphite (manufactured by Air Water Co., Ltd., MZ-260, expansion start temperature 260 ° C. or more, average aspect ratio 25.3) 18 Parts by mass, 2 parts by mass of lead-based stabilizer (Sho Chemical Co., Ltd., SL-1000), 0.5 parts by mass of polyethylene-based lubricant (Mitsui Chemical Co., Ltd., Hi-Wax 4202E), aluminum hydroxide (Showa Denko Co., Ltd.) After blending 3 parts by mass of H-42S (manufactured by Company), the mixture was stirred and mixed using a Henschel mixer (manufactured by Kawada Kogyo Co., Ltd.) having an inner volume of 200 liters to obtain a resin composition (B-1).
The resin composition which comprises a surface layer and an inner layer was obtained as follows.
2 parts by mass of a lead-based stabilizer (SL-1000, manufactured by Sakai Chemical Co., Ltd.), 100 parts by mass of polyvinyl chloride resin (TH 1000, manufactured by Taiyo PVC Co., Ltd.), polyethylene-based lubricant (HIWAX 4202E, manufactured by Mitsui Chemicals, Inc.) After blending 0.5 parts by mass and 3 parts by mass of calcium carbonate (manufactured by Shiraishi Calcium Co., Ltd., Whiteton SB), the resin composition is mixed by stirring with a Henschel mixer (manufactured by Kawada Kogyo Co., Ltd.) having an inner volume of 200 liters. B-2) was obtained.
The resin composition (B-2) is supplied to the hopper 66 of the first extruder 61 using the manufacturing apparatus shown in FIG. 2, and the resin composition (B-) is supplied to the hopper 67 of the second extruder 62. 1) was supplied. The resin temperature in the first extruder 68 and the second extruder 69 was set to 180 ° C., and each resin was supplied from the first extruder 68 and the second extruder 69 to the mold 70. The molding temperature in the mold 70 is set to 190 ° C., and extrusion molding is performed in a tubular shape, and the outer layer 114 mm, the resin composition (B-2), and the surface layer and inner layer each having a thickness of 0.8 mm, and the resin composition The piping material provided with an intermediate layer which was constituted by object (B-1) and which was formed between the surface layer and the inner layer and which had a thickness of 4 mm was produced. The piping material was cut to produce three pipes 21, 22 and 23.

[Linear expansion coefficient]
It measured based on the thermomechanical analysis method (TMA method) prescribed | regulated to JISK7197. The results are shown in Table 1.

[Fusion strength]
A universal tester 50 shown in FIG. 8 was prepared. The universal tester 50 includes a punching jig 51 and two compression plates (not shown). The punching jig 51 includes a pedestal 51 a and a pressing portion 51 b disposed above the pedestal 51 a. The punching jig 51 is sandwiched between two compression plates (not shown).
Next, the piping material was cut into a tube having a width of 20 mm in the axial direction of the pipe, and this was used as a test piece 25. The test piece 25 has an inner layer 26, an intermediate layer 27, and a surface layer (not shown).
Test piece 25 is set between pedestal part 51a and indentation part 51b of universal testing machine 50 under conditions of temperature 23 ° C. ± 2 ° C. and humidity always (45 to 85%), and two compression plates The test piece 25 is compressed at a speed of 10 mm / min ± 2 mm / min in the direction of the tube axis by the following method, and the maximum load when the fusion bonded surface of the inner layer 26 and the intermediate layer 27 peels is determined. The fusion strength was calculated by 1) and (2). The results are shown in Table 1.
F = W / S (1)
S = 3.14 × d × L (2)
[In the formulas (1) and (2), F is the fusion strength (MPa), W is the maximum load (N), S is the fusion area (cm ² ), d is the average of the inner layer 26 Outer diameter (cm), L is test specimen length in the tube axis direction (cm)]

[Formability evaluation]
The appearance of the obtained piping material is observed, and there is either warpage or exfoliation between the middle layer and the surface layer, and one having a significant degree is regarded as “x”, and either warpage or exfoliation between the middle layer and the surface layer is Although there is a certain thing, the thing which the extent can accept was made into "(triangle | delta)", and the thing without either was made into "(circle)". The results are shown in Table 1.

[Fire resistance evaluation]
The fireproof test furnace 100 shown in FIG. 9 was prepared. The fireproof test furnace 100 includes a heating chamber 110 sealed except at the upper side, a test floor slab 120 installed above the heating chamber 110, and a burner 130 provided in the heating chamber 110 to generate a flame. And a thermocouple 140 for measuring the temperature in the heating chamber 110. As the floor slab 120, a PC (precast concrete) panel having a thickness of 100 mm and having a section penetration portion 120a with a diameter of 260 mm was used. The thermocouple 140 was disposed so as to measure the temperature in the vicinity of the lower end of the piping member 20 (first upright pipe 21) in the heating chamber 110. Further, the mortar 3 was filled between the pipe joint 10 and the inner side surface of the section penetrating portion 120a to seal the section penetrating portion 120a.
The piping structure 1 was installed in the same arrangement as that of the above embodiment, using the pipe joint 10 and the piping material 20 manufactured as described above in the fire resistance test furnace 100.
And fire resistance test (The evaluation method of the fire resistance performance test of the revised Building Standard Law enforced on June 1, 2000, according to ISO834-1) was done. In this fire resistance test, the time (smoke generation time) until smoke is emitted from the gap between the pipe joint 10 and the section penetrating portion 120a after heating was measured. Fire resistance is considered to be fire when the smoke time is 120 minutes or more, and fire resistance is not fire when it is less than 120 minutes, according to the judgment criteria of the 8th division of the Fire Service Law.
When the fire resistance test was conducted on the piping structure of Example 1, the smoke did not flow out from between the pipe joint 10 and the section penetrating portion 120a even if it exceeded 120 minutes from the start of heating, and it had fire resistance. Was.

(Example 2)
Stabilizer added to the resin composition (B-2) constituting the surface layer and the inner layer, wherein the amount of thermally expandable graphite compounded in the resin composition (B-1) constituting the intermediate layer of the piping material is 16 parts by mass 2 parts by mass of a tin-based stabilizer (manufactured by Nitto Kasei Co., Ltd., AT-6300) and 3 parts by mass of aluminum hydroxide as an endothermic agent were used to prepare a piping material in the same manner as Example 1. With respect to the piping material of Example 2, the linear expansion coefficient was measured in the same manner as in Example 1 by the above-mentioned method, the fusion bonding strength was calculated, and the formability evaluation and the fire resistance evaluation were performed. The piping material of Example 2 was excellent in moldability and had fire resistance. The results are shown in Table 1.

(Example 3)
Example 1 except that the amount of thermally expandable graphite blended in the resin composition (B-1) constituting the middle layer of the piping material is 20 parts by mass, and the thicknesses of the surface layer and the inner layer are each 1.3 mm Piping materials were produced in the same manner as in the above. The linear expansion coefficient of the piping material of Example 3 was measured in the same manner as in Example 1 by the above-mentioned method, the fusion bonding strength was calculated, and the formability evaluation and the fire resistance evaluation were performed. The piping material of Example 3 was excellent in moldability and had fire resistance. The results are shown in Table 1.

(Example 4)
Thermally expandable graphite A (expansion start temperature 280 prepared by the method described in Example 2 of Patent No. 5130295 as thermally expandable graphite to be blended with the resin composition (B-1) constituting the intermediate layer of piping material A piping material was produced in the same manner as in Example 1 except that 18 parts by mass of ° C. and an average aspect ratio of 17.9) were used. With respect to the piping material of Example 4, the linear expansion coefficient was measured in the same manner as in Example 1 by the above-mentioned method, the fusion bonding strength was calculated, and the formability evaluation and the fire resistance evaluation were performed. The piping material of Example 4 was excellent in moldability and had fire resistance. The results are shown in Table 2.

(Example 5)
Thermally expandable graphite B (expansion start temperature 290) prepared by the method described in Example 2 of Patent No. 5084930 as thermally expandable graphite to be blended with the resin composition (B-1) constituting the intermediate layer of piping material A piping material was produced in the same manner as in Example 1 except that 18 parts by mass of ° C., average aspect ratio 14.1) was used. With respect to the piping material of Example 5, the linear expansion coefficient was measured in the same manner as in Example 1 by the above-mentioned method, the fusion bonding strength was calculated, and the formability evaluation and the fire resistance evaluation were performed. The piping material of Example 5 was excellent in moldability and had fire resistance. The results are shown in Table 2.

(Example 6)
The amount of thermally expandable graphite blended in the resin composition (B-1) constituting the middle layer of the piping material is 20 parts by mass, the amount of the lead-based stabilizer is 4 parts by mass, and the thicknesses of the surface layer and the inner layer are A piping material was manufactured in the same manner as in Example 1 except that each was 1.3 mm, the resin temperature in the second extruder was 200 ° C., and the molding temperature in the mold was 225 ° C. . The linear expansion coefficient of the piping material of Example 6 was measured in the same manner as in Example 1 according to the above-mentioned method, the fusion bond strength was calculated, and the formability evaluation and the fire resistance evaluation were performed. The piping material of Example 6 was excellent in moldability and had fire resistance. The results are shown in Table 2.

(Example 7)
A pipe joint was produced in the same manner as in Example 1 except that the amount of the endothermic agent blended in the resin composition (A-1) constituting the pipe joint was 0.5 parts by mass. Furthermore, the piping material was produced like Example 1 except the quantity of aluminum hydroxide mix | blended with the resin composition (B-1) which comprises the intermediate | middle layer of piping material having been 1 mass part. Fire resistance evaluation was implemented like Example 1 except having used this pipe joint and piping material. The pipe joint of Example 7 was resistant to deformation and had fire resistance. The results are shown in Table 3.
Moreover, about the piping material of Example 7, it carried out similarly to Example 1 by said method, measured the linear expansion coefficient, computed fusion | melting strength, and implemented moldability evaluation. The piping material of Example 7 was excellent in formability. The results are shown in Table 3.

(Example 8)
Magnesium hydroxide as an endothermic agent to be added to the resin composition (A-1) constituting the pipe joint (Kysuma 8, manufactured by Kyowa Chemical Industry Co., Ltd., volume average particle diameter: 1.5 μm, BET specific surface area: 3.1 m ² A pipe joint was produced in the same manner as in Example 1 except that 2 parts by mass of / g) was used. Furthermore, the piping material was produced like Example 1 except the quantity of aluminum hydroxide mix | blended with the resin composition (B-1) which comprises the intermediate | middle layer of piping material having been 1 mass part. Fire resistance evaluation was implemented like Example 1 except having used this pipe joint and piping material. The pipe joint of Example 8 was resistant to deformation and had fire resistance. The results are shown in Table 3.
Moreover, about the piping material of Example 8, it carried out similarly to Example 1 by said method, measured the linear expansion coefficient, computed fusion | melting strength, and implemented moldability evaluation. The piping material of Example 8 was excellent in formability. The results are shown in Table 3.

(Example 9)
Kaolinite (Bass Co., Ltd., ASP-900, volume average particle diameter: 1.5 μm, BET specific surface area: 12.2 m ² / g) as an endothermic agent to be added to the resin composition (A-1) constituting the pipe joint A pipe joint was produced in the same manner as in Example 1 except that 3 parts by mass was used. Furthermore, the piping material was produced like Example 1 except the quantity of aluminum hydroxide mix | blended with the resin composition (B-1) which comprises the intermediate | middle layer of piping material having been 1 mass part. Fire resistance evaluation was implemented like Example 1 except having used this pipe joint and piping material. The pipe joint of Example 9 was resistant to deformation and had fire resistance. The results are shown in Table 3.
Further, for the piping material of Example 9, the linear expansion coefficient was measured in the same manner as in Example 1 by the above-mentioned method, the fusion bond strength was calculated, and the formability was evaluated. The piping material of Example 9 was excellent in formability. The results are shown in Table 3.

(Example 10)
Thermally expandable graphite C (expansion start temperature 275 prepared by the method described in Example 5 of Japanese Patent No. 5130295 as thermally expandable graphite to be blended with the resin composition (B-1) constituting the intermediate layer of piping material A piping material was produced in the same manner as in Example 1 except that an average aspect ratio of 33.1 ° C. was used. The linear expansion coefficient of the piping material of Example 10 was measured in the same manner as in Example 1 according to the above-mentioned method, the fusion bond strength was calculated, and the formability evaluation and the fire resistance evaluation were performed. The piping material of Example 10 had fire resistance. The results are shown in Table 4.

(Example 11)
The piping material was manufactured like Example 1 except resin temperature in the 2nd extruder at the time of producing piping material being 145 ° C, and forming temperature in a metallic mold having been 170 ° C. With respect to the piping material of Example 11, the linear expansion coefficient was measured in the same manner as in Example 1 by the above method, the fusion bonding strength was calculated, and the formability evaluation and the fire resistance evaluation were performed. The piping material of Example 11 had fire resistance. The results are shown in Table 4.

(Comparative example 1)
Pipe joints were produced in the same manner as in Example 1 except that magnesium hydroxide was not blended in the resin composition (A). The fire resistance was evaluated in the same manner as in Example 1 except that this pipe joint was used, and the pipe joint was deformed in less than 120 minutes from the start of heating, and the gap between the pipe joint 10 and the section penetrating portion 120a Was formed, and the smoke leaked from the gap. That is, in the piping structure of Comparative Example 1, fire resistance could not be sufficiently exhibited.
Moreover, about the piping material of the comparative example 1, a linear expansion coefficient was measured by said method similarly to Example 1 by said method, fusion bond strength was computed, and moldability evaluation was implemented. The piping material of Comparative Example 1 was excellent in formability. The results are shown in Table 5.

(Comparative example 2)
Thermal expandable graphite D (manufactured by Tosoh Co., Ltd., GREP-EG, expansion start temperature 220 ° C., aspect ratio) as thermally expandable graphite to be blended with the resin composition (B-1) constituting the intermediate layer of piping material A piping material was produced in the same manner as in Example 1 except that 18.2) was used. The linear expansion coefficient of the piping material of Comparative Example 2 was measured in the same manner as in Example 1 according to the above-mentioned method, the fusion bonding strength was calculated, and the formability evaluation and the fire resistance evaluation were performed. The piping material of Comparative Example 2 could not sufficiently exhibit the fire resistance and the formability. The results are shown in Table 5.

DESCRIPTION OF SYMBOLS 1 Piping structure 2 Floor slab 2a Section penetration part 3 mortar 4 Flooring 10 Pipe joint 10a Upper pipe joint 10b Lower pipe joint 11 Main pipe part 11a, 11b Socket 12 Horizontal branch pipe connection part 12a Socket 13a, 13b Socket 20 Piping material 21 1st standing pipe (piping material)
22 2nd standing pipe (piping material)
23 Horizontal branch pipe (pipe material)

Claims (9)

A pipe structure comprising a pipe joint having a socket and a pipe, wherein the socket and the pipe are connected within the section penetration portion of the floor slab,
The pipe joint contains a resin composition (A) containing a polyvinyl chloride resin and an endothermic agent,
The content of the endothermic agent in the resin composition (A) is 0.01 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin,
The piping material has a multilayer structure including at least a surface layer, an intermediate layer, and an inner layer,
The surface layer and the inner layer contain polyvinyl chloride resin,
The intermediate layer contains a resin composition (B) containing a polyvinyl chloride resin and thermally expandable graphite having a thermal expansion start temperature of 260 ° C. or higher,
The piping structure whose content of the said thermally expandable graphite in the said resin composition (B) is 15.0 mass parts or more and 26.0 mass parts or less with respect to 100 mass parts of polyvinyl chloride-type resin. The piping structure according to claim 1, wherein the outer surface of the end portion of the piping material is a tapered surface .   The piping structure according to claim 1, wherein an average aspect ratio of the thermally expandable graphite is 30 or less. The pipe material, the linear expansion coefficient defined in JIS K 7197 is less than ^{7.0 × 10 -5 / ℃ 4.5 ×} 10 -5 / ℃ above, in any one of claims 1 to 3 Piping structure as described.   The piping structure according to any one of claims 1 to 4, wherein the piping material has a fusion strength of 0.8 MPa or more between the inner layer and the intermediate layer. The resin composition (B) contains aluminum hydroxide,
The content of the said aluminum hydroxide in the said resin composition (B) is 0.1 mass part or more and 20.0 mass parts or less with respect to 100 mass parts of polyvinyl chloride-type resin. The piping structure according to any one of the preceding claims. The fitting is transparent and
The endothermic agent in the resin composition (A) is at least one heat-dehydrating compound selected from magnesium hydroxide, aluminum hydroxide, kaolin-based minerals and hydrotalcites,
The resin composition (A) contains a tin based stabilizer, the content of the tin-based stabilizer for 100 parts by weight of the polyvinyl chloride resin is Ri der than 5.0 part by mass 0.3 parts by mass ,
Fire resistance test is performed according to the evaluation method (ISO 834-1) of fire resistance performance test of the revised Building Standard Law enforced on June 1, 2000, and smoke is emitted from the gap between the pipe joint and the section penetration part fuming time Ru der more than 120 minutes,
The piping structure according to any one of claims 1 to 6 (however, except that the pipe joint contains 0.5 parts by mass or more of calcium carbonate) . A method for producing a piping material having a three-layer structure, wherein the surface layer and the inner layer contain a polyvinyl chloride resin, and the middle layer contains a polyvinyl chloride resin and thermally expandable graphite having a thermal expansion start temperature of 260 ° C. or higher. ,
The molding temperature is at least 175 ° C and less than 240 ° C,
The manufacturing method of piping material whose kneading | mixing temperature of the resin composition which comprises the said intermediate | middle layer is higher than the kneading | mixing temperature of the resin composition which comprises the said surface layer and the said inner layer. The piping material contains a heat stabilizer,
The manufacturing method of the piping material of Claim 8 in which content of the heat stabilizer with respect to 100 mass parts of polyvinyl chloride-type resin is more with the said middle class than the said surface layer and the said inner layer.

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