JP2023150903A - Joint - Google Patents

Abstract

To suppress a joint body from being locally overheated.SOLUTION: A joint comprises a joint body 21 and a resin-made sound insulation cover 22 which covers the joint body 21 from radially outside the joint body 21, and is provided with a space S between the joint body 21 and the sound insulation cover 22, where the sound insulation cover 22 has a rigidity of 13 to less than 40 cm, the rigidity of the sound insulation cover 22 being defined as bending resistance (cm) measured based upon JIS L-1096:2010(45° cantilever method).SELECTED DRAWING: Figure 1

Description

The present invention relates to a joint.

Conventionally, a joint described in Patent Document 1 below has been known. This joint includes a joint body, a spacer, and a sound insulation cover. The spacer is a foam tape of closed cell polyethylene foam. The spacer is wrapped around the joint body. The sound insulation cover is made of soft vinyl chloride resin. The sound insulation cover is wrapped around the joint body over the spacer.
Here, a space (air layer) is provided between the joint body and the sound insulation cover. The spacer supports the sound insulation cover and maintains the aforementioned space.

Patent No. 5879047

In the joint, when the joint is heated for some reason, heat may be trapped in the spacer and the joint body may be locally overheated.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to suppress local overheating of the joint body.

<1> A joint according to one aspect of the present invention includes a joint body and a resin sound insulation cover that covers the joint body from the outside in a radial direction of the joint body, and the joint body and the sound insulation cover A space is provided between them, and when the rigidity of the sound insulation cover is defined as bending resistance (cm) measured in accordance with JIS L-1096:2010 (45° cantilever method), the stiffness of the sound insulation cover is The rigidity is 13 cm or more and less than 40 cm.

The axial rigidity of the sound insulation cover is 13 cm or more and less than 40 cm. Therefore, the sound insulating cover has sufficient rigidity in the axial direction. Thereby, the spacer between the joint body and the sound insulation cover can be eliminated, or even if a spacer is provided, the spacer can be minimized. Therefore, even if the joint body is heated for some reason, overheating of the joint body due to the spacer is suppressed.

<2> In the joint according to <1> above, the sound insulating cover may be made of olefin resin that does not contain a plasticizer.

When the sound insulation cover is made of soft vinyl chloride resin as in the conventional joint, it is necessary to add a plasticizer to the soft vinyl chloride resin in order to adjust the rigidity of the sound insulation cover.
In the joint of this embodiment, the sound insulation cover is made of olefin resin. In this case, unlike the case where the sound insulation cover is made of soft vinyl chloride resin, it is not necessary to add a plasticizer to the olefin resin (sound insulation cover).
Here, if a plasticizer is added to the sound insulation cover, the plasticizer will migrate to other members that are in contact with the sound insulation cover. Examples of the other members include the joint body. The other member may also include, for example, a tape for fixing the sound insulating cover to the joint body.
In order to restrict the migration of plasticizer to the joint body, it is conceivable to provide a nonwoven fabric layer between the joint body and the sound insulating cover. However, in this case, heat tends to accumulate in the space between the joint and the sound insulation cover due to the nonwoven fabric layer.
When the plasticizer migrates to the tape, the adhesiveness of the tape decreases, and there is a risk that the tape will peel off and the sound insulating cover may also peel off from the joint body.
Therefore, when the sound insulation cover does not contain a plasticizer as in this embodiment, heat does not easily accumulate in the space between the joint and the sound insulation cover, and peeling of the sound insulation cover from the joint body can be suppressed. can.

<3> In the joint according to <1> or <2> above, at least a portion of the space in the axial direction of the joint body is annular and continuous in the circumferential direction of the joint body. Good too.

At least a portion of the space between the joint body and the sound insulation cover in the axial direction is annular and continuous in the circumferential direction of the joint body. Therefore, heat can be convected in the circumferential direction within the space.

<4> In the joint according to any one of the aspects <1> to <3>, the joint main body is arranged at a main pipe extending in the axial direction of the joint main body and at both ends of the main pipe in the axial direction. two sockets, the outer diameter of the main pipe is smaller than the outer diameter of the two sockets, and both ends of the sound insulation cover in the axial direction are fixed to each of the two sockets. , the space may be provided between the main pipe and the sound insulation cover.

According to the present invention, local overheating of the joint body can be suppressed.

FIG. 1 is a cross-sectional view of a joint according to an embodiment of the present invention, showing a side view of the joint body. 2 is a cross-sectional view corresponding to the II-II cross-sectional view shown in FIG. 1. FIG. FIG. 2 is a developed view of a sound insulating cover that constitutes the joint shown in FIG. 1. FIG. FIG. 2 is a perspective view of an original fabric of a sound insulation cover that constitutes the joint shown in FIG. 1; 2 is a diagram illustrating a test method for measuring the rigidity of a sound insulation cover that constitutes the joint shown in FIG. 1. FIG. It is a figure explaining the test method of the fire resistance of a joint in a verification test.

Hereinafter, a piping structure 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5.
As shown in FIG. 1, a piping structure 10 is provided in a building 1 (building). The piping structure 10 penetrates a slab 2 (for example, a floor slab) of the building 1 in the vertical direction Z. The slab 2 divides floors in the building 1. The piping structure 10 may have fire resistance. The piping structure 10 may be, for example, a drain pipe, a water supply pipe, or a ventilation pipe. The piping structure 10 includes a joint 20 (pipe joint) and a pipe 30. The joint 20 may be a fireproof joint, and the pipe 30 may be a fireproof pipe.

(Joint 20)
Examples of the joint 20 include a so-called socket, a cheese, a collective joint, and the like. As shown in FIGS. 1 and 2, the joint 20 includes a joint body 21 and a sound insulation cover 22. The joint body 21 includes a main pipe 23 and a socket 24. The axis O of the main pipe 23 is along the vertical direction Z. The sockets 24 are arranged at both ends of the main pipe 23 in the vertical direction Z. The joint body 21 is provided with one socket 24 at each of the upper and lower ends of the main pipe 23. The joint body 21 includes two sockets 24. The two sockets 24 are arranged coaxially with each other (on the axis O). The outer diameter of the main pipe 23 is smaller than the outer diameters of the two sockets 24. Note that the joint body 21 may further include one or more branch pipes (not shown). The branch pipe extends from the main pipe 23 in the radial direction (horizontal direction).

(Joint body 21)
The joint body 21 is made of resin (for example, made of hard vinyl chloride resin, which is a polyvinyl chloride resin that does not contain a plasticizer), and has a shape that follows the nominal diameter of 30 to 150 mm for DV joints defined in JIS K 6739. Although this is the size, the nominal diameter may be larger than this. In particular, in the present invention, the rigidity of the sound insulating cover 22 is high, and the use of spacers that are disadvantageous to fire resistance can be reduced, so the slab through-hole becomes large and medium diameter (nominal diameter 65 or more) (socket inner diameter 76 mm or more) is disadvantageous to fire resistance. ), the effect is remarkable for joints with a nominal diameter of 125 or less (socket inner diameter of 140 mm or less)), and large diameters (nominal diameter of 150 or more (socket inner diameter of 165 mm or more), nominal diameter of 300 or less (socket inner diameter of 318 mm or less)). The effect is particularly noticeable at joints. The joint body 21 is produced by injection molding the resin composition (A).

[Resin composition (A)]
Examples of the polyvinyl chloride resin contained in the resin composition (A) include a polyvinyl chloride homopolymer; a vinyl chloride monomer and another monomer having an unsaturated bond copolymerizable with the vinyl chloride monomer; Copolymer: Examples include graft copolymers obtained by graft copolymerizing vinyl chloride monomers onto polymers other than polyvinyl chloride resins. The polyvinyl chloride resins may be used alone or in combination of two or more.
The polyvinyl chloride resin may be further chlorinated. Examples of methods for chlorinating polyvinyl chloride resins include thermal chlorination methods, photochlorination methods, and the like.

Other monomers having unsaturated bonds copolymerizable with the vinyl chloride monomer include, for example, 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 ether; (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl acrylate; aromatic vinyls such as styrene and α-methylstyrene; N-phenylmaleimide, N- Examples include N-substituted maleimides such as cyclohexylmaleimide. The other monomers may be used alone or in combination of two or more.

Examples of the polymer to be graft-copolymerized with the vinyl chloride monomer include ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide copolymer, ethylene-ethyl acrylate copolymer, and ethylene-butyl acrylate monomer. Examples include carbon oxide copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, acrylonitrile-butadiene copolymer, polyurethane, chlorinated polyethylene, and chlorinated polypropylene. These polymers may be used alone or in combination of two or more.

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

The average degree of polymerization of the polyvinyl chloride resin is preferably 400 or more and 1000 or less, more preferably 600 or more and 900 or less. Here, the average degree of polymerization is determined based on JIS K- This is the average degree of polymerization measured in accordance with 6721 "Test Method for Vinyl Chloride Resin."
If the average degree of polymerization of the polyvinyl chloride resin is equal to or higher than the lower limit, the mechanical strength can be sufficiently increased, and if it is equal to or lower than the upper limit, sufficient moldability can be ensured.

The resin composition (A) may contain an endothermic agent. An endothermic agent is a compound that has an endothermic action and suppresses the rise in temperature when heated due to a fire or the like. For example, a compound that causes an endothermic reaction such as a dehydration reaction when heated can be used as the endothermic agent.
Compounds that undergo a dehydration reaction when heated include, for example, magnesium hydroxide, aluminum hydroxide, inorganic hydroxides such as kaolin minerals (kaolinite, halloysite, dickite) and hydrotarsalcite, sepiolite, bentonite, Examples include inorganic compounds with water-absorbing properties such as montmorillonite, talc, mica, quartz, zeolite, wollastonite, and nepheline cyanite. Hereinafter, inorganic hydroxides and inorganic compounds that undergo a dehydration reaction when heated are collectively referred to as "heat-dehydrated compounds." In heat-dehydrated compounds, temperature rise can also be suppressed by the latent heat of vaporization of water generated by the dehydration reaction.
Among heat-dehydrated compounds, magnesium hydroxide undergoes a dehydration reaction at 300° C. or higher, so when magnesium hydroxide is used as an endothermic agent, the joint body 21 is produced by molding the resin composition (A). It is possible to suppress the occurrence of a dehydration reaction.
Among heat-dehydrating compounds, aluminum hydroxide undergoes a dehydration reaction at about 200°C, so when aluminum hydroxide is used as an endothermic agent, it quickly absorbs the heat transferred to the joint body 21 in the event of a fire. be able to. Therefore, it is possible to further suppress deterioration of fire resistance due to deformation of the joint body 21 before the pipe 30 thermally expands.

Among heat-dehydrated compounds, hydrotalcite, whose chemical name is magnesium aluminum hydroxide carbonate hydrate, is a type of mineral represented by Mg ₆ Al ₂ (OH) ₁₆ CO ₃ 4H ₂ O, etc. It is a layered inorganic compound consisting of a 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- . be. Many divalent and trivalent metals have layered structures similar to this, and these are represented by the following general formula.
[M ²⁺ _1-x M ³⁺ _x (OH) ₂ ] ^x+ [A ^n- _x/n・mH 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⁺ A ^n- : n-valent anion such as CO ₃ ^2- , Cl ^- , NO ₃ ^-, etc. X: 0<X≦0.33
Hydrotalcite starts dehydrating the water of crystallization that it has between molecules at about 180°C, and the water of crystallization is completely eliminated at about 300°C. Until this state, synthetic hydrotalcite maintains its crystalline structure, but when the temperature exceeds about 350°C, the crystalline structure begins to collapse and releases water and carbon dioxide. Synthetic hydrotalcite starts endothermic decomposition at a temperature lower than the thermal decomposition temperature of vinyl chloride resin, which is approximately 200°C or more and 300°C or less, by 60°C or more and 75°C or less. can be effectively suppressed by endothermic decomposition of hydrotalcite.
As the endothermic agent, at least two of magnesium hydroxide, aluminum hydroxide, kaolin mineral, or hydrotalcite may be used in combination.

The heat-dehydrated compound is usually in the form of particles.
The volume average particle diameter of the heat-dehydrated compound is preferably 0.01 μm or more and 20 μm or less, more preferably 0.05 μm or more and 2 μm or less, and even more preferably 0.05 μm or more and 1 μm or less. By setting the volume average particle diameter of the heat-dehydrated compound within this range, transparency can be imparted to the joint body 21 and the dispersibility of the heat-dehydrated compound can be improved. The volume average particle size is a value measured using a laser diffraction scattering particle size distribution measuring device.
The BET specific surface area of the heat-dehydrated compound is preferably 1 m ² /g or more and 40 m ² /g, and preferably 1 m ² /g or more and 20 m ² /g or less. Here, the BET specific surface area is a value determined using nitrogen adsorption.
If the volume average particle diameter and BET specific surface area of the heat-dehydrated compound are within the above ranges, the effect as an endothermic agent can be sufficiently exhibited, and the moldability of the resin composition (A) when producing the joint body 21 is improved. In addition, sufficient mechanical properties of the joint body 21 can be ensured.

The particle surface of the heat-dehydrated compound is preferably surface-treated with a higher fatty acid such as stearic acid or a surface treatment agent such as a silane coupling agent. A heat-dehydrated compound that has been surface-treated with a surface treatment agent has a higher dispersibility in a polyvinyl chloride resin, and is more likely to exhibit an endothermic effect. Furthermore, when the heat-dehydrated compound is basic, it can make the polyvinyl chloride resin less prone to fading and prevent yellowing.
When the heat-dehydrated compound is surface-treated with a surface treatment 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 based on 100 parts by mass of the heat-dehydrated compound. If the amount of the surface treatment agent is at least the above lower limit, the dispersibility of the heat-dehydrated compound in the polyvinyl chloride resin can be sufficiently increased, and if it is at most the above upper limit, a decrease in economic efficiency can be suppressed.

The content of the heat absorbing agent in the resin composition (A) is preferably 0.01 parts by mass or more and 10.0 parts by mass or less, and 0.05 parts by mass or more and 5 parts by mass or less, based on 100 parts by mass of the polyvinyl chloride resin. It is more preferably 0.0 parts by mass or less, and even more preferably 0.1 parts by mass or more and 2.0 parts by mass or less. If the content of the heat absorbing agent in the resin composition (A) is at least the lower limit value, the deformation of the joint body 21 can be further suppressed in the event of a fire, and if the content is at most the upper limit value, the joint body 21 can be manufactured. The moldability during the process can be sufficiently increased, and the mechanical properties of the joint body 21 can also be improved.

The resin composition (A) may contain a flame retardant other than the heat absorbing agent as long as the effects of the present invention are not impaired.
Other flame retardants include hydrotalcite, antimony oxides such as antimony dioxide, antimony trioxide, and antimony pentoxide; molybdenum compounds such as molybdenum trioxide, molybdenum disulfide, and ammonium molybdate; tetrabromobisphenol A, and tetrabromoethane. , tetrabromoethane, tetrabromoethane; phosphorus compounds such as triphenyl phosphate, ammonium polyphosphate; and boric acid compounds such as calcium borate and zinc borate. Among the other flame retardants, antimony trioxide is preferred because it has a high effect of suppressing the combustion of polyvinyl chloride.

In addition, the resin composition (A) may include a lubricant, a processing aid, an impact modifier, a heat resistance improver, an antioxidant, a heat stabilizer, a heat stabilization aid, within a range that does not impair the effects of the present invention. Additives such as light stabilizers, UV absorbers, pigments, plasticizers, thermoplastic elastomers, etc. may also be included.
Each of the additives described below may be used alone or in combination of two or more.

Examples of the heat stabilizer include lead-based stabilizers, tin-based stabilizers, Ca--Zn-based stabilizers, higher fatty acid metal salts, and the like. One type of heat stabilizer may be used alone, or two or more types may be used in combination.
Examples of lead-based stabilizers include white lead, basic lead sulfite, tribasic lead sulfate, dibasic lead phosphite, dibasic lead phthalate, tribasic lead maleate, and silica gel co-precipitated silicic acid. Examples include lead, dibasic lead stearate, lead stearate, lead naphthenate, and the like.
Examples of tin-based stabilizers include mercaptides such as dibutyltin mercapto, dioctyltin mercapto, and dimethyltin mercapto; malates such as dibutyltin maleate, dibutyltin maleate polymer, dioctyltin maleate, and dioctyltin maleate polymer; Examples include carboxylates such as tin mercapto dibutyltin laurate and dibutyltin laurate polymers.
The Ca--Zn stabilizer is a mixture of fatty acid salts of calcium and fatty acid salts of zinc. Examples of fatty acids include behenic acid, stearic acid, lauric acid, oleic acid, palmitic acid, ricinoleic acid, and benzoic acid, and two or more of these may be used in combination.
Examples of higher fatty acid metal salts include lithium stearate, magnesium stearate, calcium stearate, calcium laurate, calcium ricinoleate, strontium stearate, barium stearate, barium laurate, barium ricinoleate, cadmium stearate, and cadmium laurate. , cadmium ricinoleate, cadmium naphthenate, cadmium 2-ethylhexoate, zinc stearate, zinc laurate, zinc ricinoleate, zinc 2-ethylhexoate, lead stearate, dibasic lead stearate, lead naphthenate, etc. It will be done.
Among these, when making the joint body 21 transparent, tin-based stabilizers or Ca-Zn-based stabilizers are preferred, and as tin-based stabilizers, those that do not contain sulfur, such as malates and carboxylates, are preferred to avoid sulfur contamination. Stearate is particularly preferred as the Ca--Zn stabilizer 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 based on 100 parts by mass of the polyvinyl chloride resin. If the content of the heat stabilizer is above the lower limit, it can improve the thermal stability of the polyvinyl chloride resin during molding, and if it is below the lower limit, it will improve the thermal stability of the polyvinyl chloride resin during combustion. can be sufficiently carbonized and sufficient fire resistance performance can be obtained.

Examples of the thermal stabilization aid include epoxidized soybean oil, phosphate ester, polyol, hydrotalcite, zeolite, and the like.
Examples of the light stabilizer include hindered amine light stabilizers.
Examples of the ultraviolet absorber include salicylic acid ester ultraviolet absorbers, benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, and cyanoacrylate ultraviolet absorbers.

Examples of pigments include organic pigments such as azo pigments, phthalocyanine pigments, threne pigments, and dye lake pigments; oxide pigments, molybdenum chromate pigments, sulfide/selenide pigments, and ferrocyanide pigments. Inorganic pigments such as

(Sound insulation cover 22)
The sound insulation cover 22 covers the joint body 21 from the outside in the radial direction of the joint body 21. As shown in FIGS. 1 to 3, the sound insulation cover 22 is long and is wrapped around the joint body 21. As shown in FIGS. The longitudinal direction A of the sound insulation cover 22 is the circumferential direction of the joint body 21. The transverse direction B of the sound insulation cover 22 is the axial direction (vertical direction Z) of the joint body 21. Both ends of the sound insulating cover 22 in the longitudinal direction A are fixed by fixing members (not shown). Both ends of the sound insulating cover 22 in the longitudinal direction A may overlap each other, but the heat storage properties of the joint 20 at the parts where the ends overlap are higher than in other parts, and the joint body 21 is deformed. It is preferable that the end surfaces of both ends of the sound insulating cover 22 in the longitudinal direction A face each other in order to facilitate the installation. Examples of the fixing member include a hook-and-loop adhesive, tape, and the like. Note that when the joint body 21 includes a branch pipe, an opening into which the branch pipe is inserted may be provided in a portion of the sound insulation cover 22 that corresponds to the branch pipe. Here, in FIG. 2, illustration of a state in which both ends of the sound insulating cover 22 in the longitudinal direction A are fixed by fixing members is omitted.

The sound insulation cover 22 is made of resin. In this embodiment, the sound insulating cover 22 is formed into a sheet of an elastic material such as modified asphalt, elastomer, rubber, polyolefin resin, soft vinyl chloride resin, etc., and is made of polyolefin resin that does not contain a plasticizer. is preferable because of its high bending resistance, and the bending resistance can be further increased by using a resin composition (A) containing 300 to 600 parts by weight of an inorganic filler based on 100 parts by weight of the polyolefin resin.

The polyolefin resin is not particularly limited, but includes, for example, low density polyethylene, high density polyethylene, linear low density polyethylene, atactic polypropylene, isotactic polypropylene, syndiotactic polypropylene, and poly-α-olefin. Among them, polyethylene having a density of 0.87 to 0.93 g/cm ³ is preferable as the polyolefin resin. Note that if the density is less than 0.87 g/cm ³ , the strength of the sound insulation cover 22 will not be sufficient, and if it exceeds 0.93 g/cm ³ , when the sound insulation cover 22 is flattened (the axial force will be applied to the joint body 21 (when applied), there is a risk of buckling. Further, if the flexural modulus of the olefin resin is 100 to 3000 kg/cm ² , it is sufficient for strength and winding workability.
Note that the sound insulation cover 22 may contain a material different from the polyolefin resin, for example, it may contain a polyvinyl chloride resin, a polystyrene resin, an ABS resin, an AS resin, an elastomer material, etc. . Furthermore, the material may be different from the polyolefin resin, and even if it is a material with lower bending resistance than the polyolefin resin, such as modified asphalt, elastomer, rubber, soft vinyl chloride resin, etc., the thickness and inorganic It is sufficient that the material has a predetermined bending resistance by laminating it with a filler or a fiber sheet such as a nonwoven fabric.

The inorganic filler is not particularly limited, but includes, for example, silica, diatomaceous earth, alumina, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, ferrites, calcium hydroxide, magnesium hydroxide. , aluminum hydroxide, basic magnesium carbonate, calcium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, dawnite, hydrotalcite, calcium sulfate, barium sulfate, gypsum fiber, calcium silicate, talc, clay, mica, montmorillonite, Bentonite, activated clay, sepiolite, imogolite, sericite, glass fiber, glass beads, silica balloons, aluminum nitride, boron nitride, silicon nitride, carbon black, graphite, carbon fiber, carbon balloons, charcoal powder, various metal powders, titanium Potassium acid, magnesium sulfate, lead zirconate titanate, aluminum borate, molybdenum sulfide, silicon carbide, stainless steel fiber, zinc borate, various magnetic powders, slag fibers, fly ash, dehydrated sludge, etc. Among these, calcium carbonate is preferably used as the inorganic filler in view of the balance between weight and cost. Note that these may be used alone or in combination of two or more.

The sound insulation cover 22 is cut out from a raw material 50 of the sound insulation cover 22 as shown in FIG. 4, for example. The raw fabric 50 is manufactured, for example, by winding up a sheet formed by extrusion molding an olefin resin that does not contain a plasticizer. As shown in FIG. 3, the longitudinal direction A of the sound insulation cover 22 may be the extrusion direction MD of the original fabric 50, or may be a direction perpendicular to extrusion (hereinafter also simply referred to as orthogonal direction TD). The width direction B of the sound insulation cover 22 may be the extrusion direction MD or the orthogonal direction TD. In this embodiment, the longitudinal direction A of the sound insulation cover 22 is the extrusion direction MD, and the lateral direction B of the sound insulation cover 22 is the orthogonal direction TD.

In this embodiment, the rigidity of the sound insulating cover 22 in a predetermined direction is defined as bending resistance (cm) measured in accordance with JIS L-1096:2010 (45° cantilever method). A specific example of a method for measuring the rigidity of the sound insulation cover 22 is as follows.
First, the measurer cuts out a sample 60 (see FIG. 5) from the sound insulation cover 22. The sample 60 has a rectangular shape with a length of 25 cm and a width of 1 cm. The measurer cuts out the sample 60 so that the predetermined direction is the longitudinal direction of the sample 60. Three samples 60 are cut out from the sound insulation cover 22 at equal intervals in a direction orthogonal to the predetermined direction. The cut sample 60 is left on a flat place in an atmosphere of 23° C. for one hour or more, and if the sample 60 is bent, a predetermined load is applied to make it flat.
As shown in FIG. 5, the measurer places the sample 60 on a pedestal 61 in an atmosphere of 23°C. The pedestal 61 has a rectangular parallelepiped shape. One of the four side surfaces of the pedestal 61 is an inclined surface 62. The angle of inclination of the inclined surface 62 is 45 degrees. The measurer places the sample 60 on the upper surface of the pedestal 61 so that the end of the sample 60 in the predetermined direction (hereinafter also referred to as the tip 60a of the sample 60) protrudes from the upper surface of the pedestal 61 toward the inclined surface 62 side.
The measurer increases the protrusion amount L of the sample 60 from the top surface in 1 cm increments until the tip 60a of the sample 60 comes into contact with the inclined surface 62. The measurer measures the amount of protrusion L when the tip 60a of the sample 60 comes into contact with the inclined surface 62, and calculates this amount of protrusion L (cm) as the rigidity (bending resistance (cm)) of the sample 60 in a predetermined direction. shall be.
Note that when the bending resistance (cm) is significantly smaller than 25 cm, the length of the sample 60 may be 25 cm or less, may be 20 cm, or may be 15 cm. On the other hand, when the bending resistance (cm) exceeds 25 cm, the length of the sample 60 may be 25 cm or more, 30 cm, or 40 cm, and the length of the pedestal 61 may be adjusted according to the length of the sample 60. You can also increase the size.
The stiffness of the sound insulation cover 22 in a predetermined direction is determined as the average value of the stiffnesses of the three samples 60.

Note that when obtaining the sample 60 from the sound insulation cover 22 that has already been attached to the joint body 21, the sound insulation cover 22 may be in a bent state, so remove the sound insulation cover 22 from the joint body 21 and Measurement is performed after flattening the surface by applying a load, etc.

The rigidity of the sound insulation cover 22 in the vertical direction Z (the axial direction of the joint body 21), in other words, the rigidity of the sound insulation cover 22 in the lateral direction B (in this embodiment, the rigidity in the orthogonal direction TD of the original fabric 50) is as follows: The bending resistance is 13 cm or more and less than 40 cm, preferably 15 cm or more and 30 cm or less. By having a bending resistance of 13 cm or more, a space can be provided between the joint body 21 and the sound insulating cover 22 without using a spacer. Since the rigidity is less than 40 cm, the sound insulation cover 22 has appropriate flexibility and is easily deformed into a shape that follows the outer surface of the joint body 21 having a cylindrical shape.
Although the rigidity of the sound insulation cover 22 in the short direction B was evaluated, the rigidity of the sound insulation cover 22 in the direction perpendicular to the vertical direction Z (the axial direction of the joint body 21), in other words, the rigidity of the sound insulation cover 22 in the longitudinal direction The stiffness in the direction A (in this embodiment, the stiffness in the orthogonal direction TD of the raw fabric 50) is also 13 cm or more and less than 40 cm, and preferably 15 cm or more and 30 cm or less. Since the bending resistance is 13 cm or more, the sound insulation cover 22 has high rigidity in the longitudinal direction A, that is, the circumferential direction of the joint 20, so that the sound insulation cover 22 is difficult to dent even without providing a spacer on the outer surface of the joint body 21. The space S can be maintained even if the joint 20 is stored in a box and transported.
Therefore, the bending resistance of the sound insulation cover 22 is preferably 13 cm or more and less than 40 cm in all directions of the sound insulation cover 22, and preferably 15 cm or more and 30 cm or less.

Here, in general, even if a sheet has low rigidity, it becomes difficult to bend by forming it into a cylindrical shape, but the larger the diameter of the cylindrical shape, the easier it is to bend. In the sound insulation cover 22, the socket of the joint has a medium diameter (nominal diameter 65 or more (socket inner diameter 76 mm or more), nominal diameter 125 or less (socket inner diameter 140 mm or less)) or large diameter (nominal diameter 150 or more (socket inner diameter 76 mm or more)) 165 mm or more), nominal diameter 300 or less (socket inner diameter 318 mm or less), the sound insulation cover 22 is easily bent even if it is made into a cylindrical shape, and a large number of spacers are required. Therefore, by improving the rigidity of the sound insulation cover 22 itself. , it becomes easier to create space with fewer spacers in medium-diameter and large-diameter joints. For this reason, it is preferable to use a sound insulating cover 22 with a rigidity of 20 cm or more for a joint with a medium diameter or more.
The rigidity can be adjusted by adjusting the material of the sound insulation cover 22 such as the type of resin and the amount of inorganic filler, the laminated structure such as the presence or absence of a fiber sheet layer, the thickness of the sound insulation cover 22 itself, etc. It is.

The thickness of the sound insulation cover 22 is 1.0 mm or more and 4.0 mm or less, preferably 1.1 mm or more and 3.0 mm or less. If it is less than 1.0 mm, the rigidity of the sound insulation cover 22 will be insufficient, and it will be difficult to provide a space S between the joint body 21 and the sound insulation cover 22. If it exceeds 4.0 mm, the sound insulation cover 22 has high rigidity and is too heavy, making it difficult to wrap the sound insulation cover 22 around the joint body 21 and difficult to transport and install the joint.
However, if the rigidity of the sound insulation cover 22 is in the range of 13 cm or more and less than 40 cm, the thickness of the sound insulation cover 22 does not need to satisfy the above range.

The areal density of the sound insulation cover 22 is 1.5 kg/m ² or more and 4.5 kg/m ² or less, and preferably 2.5 kg/m ^{2 or} more and 4.0 kg/m ² or less. If it is less than 1.5 kg/m ² , the rigidity of the sound insulation cover 22 will be insufficient, and it will be difficult to provide a space between the joint body 21 and the sound insulation cover 22. If it exceeds 4.5 kg/m ² , the sound insulation cover 22 has high rigidity and is too heavy, making it difficult to wrap the sound insulation cover 22 around the joint body 21 and difficult to transport and install the joint.
However, if the rigidity of the sound insulation cover 22 is in the range of 13 cm or more and less than 40 cm, the areal density does not need to satisfy the above range.

As shown in FIG. 1, both upper and lower ends of the sound insulating cover 22 are fixed to two sockets 24, respectively. The sound insulating cover 22 is fixed to the joint body 21 with tape 25. The tape 25 is provided over the entire circumference in the circumferential direction. The material of the tape 25 is not particularly limited, but examples include tapes made of resin such as soft vinyl chloride resin, rubber resin, olefin resin, and acrylic resin, fiber tapes such as paper and cloth, and metal tapes such as aluminum. The material tape is provided with an adhesive layer, and particularly preferred are resin tapes such as olefin resins and acrylic resins that do not contain plasticizers, paper or cloth tapes, and aluminum tapes. The adhesive layer is not particularly limited, but includes, for example, a rubber adhesive, an acrylic adhesive, and the like.

As shown in FIGS. 1 and 2, a space S is provided between the joint body 21 and the sound insulation cover 22. The space S is provided between the main pipe 23 and the sound insulation cover 22. At least a portion of the space S in the vertical direction Z (axial direction) is continuous in the circumferential direction of the joint body 21 . When the joint main body 21 does not include a branch pipe, the space S may be continuous in the circumferential direction over the entire area in the vertical direction Z between the main pipe 23 and the sound insulation cover 22. When the joint body 21 includes a branch pipe, the space S is located between the main pipe 23 and the sound insulation cover 22 at a position where the branch pipe is avoided in the vertical direction Z (above or below the branch pipe). It may be continuous in the direction.
A fiber sheet with fire resistance and heat resistance, such as rock wool or glass wool, may be placed in the space S, and by placing these fire and heat resistant sheets throughout the space S, the joint body 21 can be Since there is no local heating, deformation of the joint body 21 can be suppressed without providing the space S.

Note that the joint 20 may include a spacer. Examples of the spacer include foam tape made of closed cell polyethylene foam. The spacer is arranged on the outer surface of the main pipe 23, for example. When the joint body 21 is provided with a spacer, the spacer is preferably provided at a position avoiding the lower end of the main pipe 23. In this case, overheating of the lower end of the main pipe 23 due to the spacer is suppressed. Moreover, it is preferable that the spacer has a shape that is longer in the circumferential direction than in the vertical direction Z. In this case, the space S between the main pipe 23 and the sound insulation cover 22 is less likely to be divided in the circumferential direction due to the spacer.

In the joint 20, at least a socket 24 located below the main pipe 23 (hereinafter simply referred to as the lower socket 24) of the joint main body 21 is embedded in the slab 2. In this embodiment, the entire lower socket 24 is buried in the slab 2. The lower end of the lower socket 24 is located at the same position as the lower surface of the slab 2 in the vertical direction Z, or located above the lower surface of the slab 2. The upper end of the lower socket 24 is located at the same position in the vertical direction Z as the upper surface of the slab 2, or located below the upper surface of the slab 2. However, the lower surface of the slab 2 may be located below the lower socket 24, and the upper surface of the slab 2 may be located above the lower socket 24. Note that the joint 20 is arranged in a section penetration portion 2a (through hole) that penetrates the slab 2, and the space between the joint 20 and the slab 2 is filled with mortar 3.

(tube 30)
Pipe 30 is connected to fitting 20. The tube 30 includes a first vertical tube 31 and a second vertical tube 32. The first vertical pipe 31 is located above the joint 20 and is connected to the upper socket 24 . The second vertical pipe 32 is located below the joint 20 and is connected to the lower socket 24 . If the fitting 20 includes a branch pipe, the tube 30 may include a lateral pipe. The lateral pipe is connected to the branch pipe. Note that the first vertical pipe 31 may not be connected to the upper socket 24, and the upper socket 24 may be closed by a lid (not shown). When the joint 20 includes a branch pipe, the branch pipe may be closed by a lid (not shown). When the joint 20 includes a plurality of branch pipes, a part of the branch pipes may be closed by a cover (not shown), and the remaining part may be connected to a horizontal pipe.

Of the tubes 30, at least the first vertical tube 31 and the second vertical tube 32 are preferably made of a resin composition containing thermally expandable graphite. The tube 30 contains a resin composition (B) containing a thermoplastic resin and thermally expandable graphite. That is, the tube 30 is produced by molding the resin composition (B) and contains a thermoplastic resin and thermally expandable graphite. Usually, the tube 30 is produced by extrusion molding the resin composition (B).
The tube 30 may have a single layer structure in which the entire tube 30 is made of the resin composition (B), or may have a multilayer structure consisting of a plurality of layers. That is, the tube 30 is composed of a tubular peripheral wall having a single-layer structure or a multi-layer structure.
When the pipe 30 has a multilayer structure, any one of the layers may be formed from the resin composition (B). For example, when the pipe 30 has a three-layer structure consisting of a surface layer, an intermediate layer, and an inner layer, the intermediate layer may be formed from the resin composition (B), and the surface layer, intermediate layer, and inner layer may be difficult to form. It may also contain a fuel. Note that the surface layer is located on the outer peripheral surface of the tubular intermediate layer, and the inner layer is located on the inner peripheral surface of the intermediate layer.
The intermediate layer has a black color 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 that they can be distinguished from the intermediate layer.
In this embodiment, the intermediate layer is a fireproof layer. Moreover, in this embodiment, the surface layer and the inner layer are coating layers, and the inner layer is the inner coating layer.

The size of the tube 30 is, for example, greater than or equal to a nominal diameter of 40 (outer diameter 48 mm) and less than or equal to nominal diameter 300 (outer diameter 318 mm).
SDR (outer diameter/thickness (wall thickness) of the tube 30) is, for example, preferably 13 or more and 35 or less, more preferably 15 or more and 33 or less, and even more preferably 17 or more and 30 or less. If the SDR is greater than or equal to the above lower limit, the thermally expandable graphite will be more likely to be oriented in the circumferential direction of the tube 30, thereby further increasing the compressive strength and lowering the thermal conductivity. If the SDR is below the above upper limit, the wall thickness will not become too thin, the compressive strength will be further increased, and the fire resistance will be further improved.

In the case of a multilayer structure, the intermediate layer may be a foamed layer or a non-foamed layer. By using a foam layer as the intermediate layer, the thermal conductivity can be further lowered.
For example, in the case of a nominal diameter of 100A (outer diameter 114 mm), the thickness of the intermediate layer is 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 2.5 mm or more. More preferably, it is 5.0 mm or less. Further, the thickness of the intermediate layer is preferably 85% or less, more preferably 70% or less, and even more preferably 60% or less of the thickness of the tube 30. When the thickness of the intermediate layer is within the above range, fire resistance and compressive strength can be further increased.

In the case of a multilayer structure, the surface layer and the inner layer may be foamed layers or non-foamed layers. By making the surface layer and the inner layer non-foamed, the strength of the tube 30 can be further increased.
For example, in the case of a nominal diameter of 100 A (outer diameter 114 mm), 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. If the thickness of the coating layer is 0.3 mm or more, the mechanical strength of the pipe 30 can be sufficiently ensured, and if it is 3.0 mm or less, a decrease in fire resistance can be suppressed.

The compression ratio of the tube 30 is preferably 20% or more, more preferably 30% or more, even more preferably 40% or more, and particularly preferably 50% or more. If the compression ratio is equal to or higher than the above lower limit, it will not be easily damaged even if it is subjected to crushing force during transportation or piping. In addition, thermally expandable graphite is oriented in the circumferential direction of the tube 30, reducing thermal conductivity. The upper limit of the compressibility of the tube 30 is substantially 90% or less.
The compressibility of the tube 30 is measured by a flatness test according to JIS K 6741:2007. Cut a circular test piece of 50 mm or more from the tube 30, leave it at 23°C for 1 hour, then sandwich it between two flat plates and measure the outer diameter of the tube 30 at a speed of 10 mm/min in a direction perpendicular to the axis of the tube 30. compress. The degree of compression in the radial direction when the three annular test pieces are broken is measured, and the average value is taken as the compression ratio. For example, if the pipe 30 is destroyed when the outer diameter has become 2/3, then 1/3 of the outer diameter has been compressed, or 33% of the outer diameter has been compressed, so the compression ratio is 33%. becomes.
The compressibility of the tube 30 depends on the composition, such as the amount and aspect ratio of thermally expandable graphite, and the type of flame retardant, as well as the structure, such as the SDR in the tube 30, the position of the weld line, the layer structure of the tube 30, and the thickness of each layer. Can be adjusted by combining surfaces.

The thermal conductivity of the tube 30 is preferably 0.3 W/m·K or less, more preferably 0.28 W/m·K or less, and even more preferably 0.25 W/m·K or less. If the thermal conductivity is below the above upper limit, condensation on the tube 30 is unlikely to occur.
The thermal conductivity of the tube 30 is a value measured in the thickness direction at three locations on the tube 30 at 23° C. in accordance with JIS A1412-2:1999.
Moreover, the thermal resistance value (the value obtained by dividing the thickness by the thermal conductivity) of the tube 30 is preferably 0.03 m ² K/W or more, and more preferably 0.04 m ² K/W or more.

[Resin composition (B)]
Thermoplastic resins contained in the resin composition (B) include crystalline resins and amorphous resins. Examples of the crystalline resin include polyethylene, polypropylene, polybutene, and the like. Examples of the amorphous resin include acrylonitrile-butadiene-styrene copolymer resin (ABS resin), polyvinyl chloride resin, and the like. As the thermoplastic resin, an amorphous resin is preferable because it can be bonded with an adhesive. In addition, from the viewpoint of flame retardancy, polyvinyl chloride resin is more preferable as the thermoplastic resin.
Examples of polyvinyl chloride resins include polyvinyl chloride homopolymers; copolymers of vinyl chloride monomers and other monomers having unsaturated bonds that can be copolymerized with vinyl chloride monomers; other than polyvinyl chloride resins. Examples include graft copolymers obtained by graft copolymerizing a vinyl chloride monomer to a polymer. The polyvinyl chloride resins may be used alone or in combination of two or more.
The polyvinyl chloride resin may be further chlorinated. Examples of methods for chlorinating polyvinyl chloride resins include thermal chlorination methods, photochlorination methods, and the like.

Other monomers having unsaturated bonds copolymerizable with the vinyl chloride monomer include, for example, 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 ether; (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl acrylate; aromatic vinyls such as styrene and α-methylstyrene; N-phenylmaleimide, N- Examples include N-substituted maleimides such as cyclohexylmaleimide. The other monomers may be used alone or in combination of two or more.

Examples of the polymer to be graft-copolymerized with the vinyl chloride monomer include ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide copolymer, ethylene-ethyl acrylate copolymer, and ethylene-butyl acrylate monomer. Examples include carbon oxide copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, acrylonitrile-butadiene copolymer, polyurethane, chlorinated polyethylene, and chlorinated polypropylene. These polymers may be used alone or in combination of two or more.

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

The average degree of polymerization of the polyvinyl chloride resin is preferably 400 or more and 1600 or less, more preferably 600 or more and 1400 or less. Here, the average degree of polymerization is determined based on JIS K- This is the average degree of polymerization measured in accordance with 6721:1999 "Test Method for Vinyl Chloride Resin."
If the average degree of polymerization of the polyvinyl chloride resin is equal to or higher than the lower limit, the mechanical strength can be sufficiently increased, and if it is equal to or lower than the upper limit, sufficient moldability can be ensured.

In addition, the resin composition (B) may include a lubricant, a processing aid, an impact modifier, a heat resistance improver, an antioxidant, a heat stabilizer, a heat stabilization aid, within a range that does not impair the effects of the present invention. Additives such as light stabilizers, UV absorbers, pigments, plasticizers, thermoplastic elastomers, etc. may also be included.
Each of the additives described below may be used alone or in combination of two or more.

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

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

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

Examples of the antioxidant include phenolic antioxidants, phosphorus antioxidants, and the like.

Examples of the heat stabilizer include lead-based stabilizers, tin-based stabilizers, Ca--Zn-based stabilizers, higher fatty acid metal salts, and the like. One type of heat stabilizer may be used alone, or two or more types may be used in combination.
Examples of lead-based stabilizers include white lead, basic lead sulfite, tribasic lead sulfate, dibasic lead phosphite, dibasic lead phthalate, tribasic lead maleate, and silica gel co-precipitated silicic acid. Examples include lead, dibasic lead stearate, lead stearate, lead naphthenate, and the like.
Examples of tin-based stabilizers include mercaptides such as dibutyltin mercapto, dioctyltin mercapto, and dimethyltin mercapto; malates such as dibutyltin maleate, dibutyltin maleate polymer, dioctyltin maleate, and dioctyltin maleate polymer; Examples include carboxylates such as tin mercapto dibutyltin laurate and dibutyltin laurate polymers.
The Ca--Zn stabilizer is a mixture of fatty acid salts of calcium and fatty acid salts of zinc. Examples of fatty acids include behenic acid, stearic acid, lauric acid, oleic acid, palmitic acid, ricinoleic acid, and benzoic acid, and two or more of these may be used in combination.
Examples of higher fatty acid metal salts include lithium stearate, magnesium stearate, calcium stearate, calcium laurate, calcium ricinoleate, strontium stearate, barium stearate, barium laurate, barium ricinoleate, cadmium stearate, and cadmium laurate. , cadmium ricinoleate, cadmium naphthenate, cadmium 2-ethylhexoate, zinc stearate, zinc laurate, zinc ricinoleate, zinc 2-ethylhexoate, lead stearate, dibasic lead stearate, lead naphthenate, etc. It will be done.
Among these, tin-based stabilizers or Ca-Zn-based stabilizers are preferred, and as tin-based stabilizers, those that do not contain sulfur, such as malates and carboxylates, are particularly preferred in order to prevent sulfur contamination. As the Zn-based stabilizer, stearate is particularly preferred from the viewpoint of 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 based on 100 parts by mass of the thermoplastic resin. If the content of the heat stabilizer is at least the above lower limit, it is possible to improve the thermal stability of the thermoplastic resin during molding, and when it is below the above upper limit, the thermoplastic resin can be sufficiently carbonized during combustion. It is possible to obtain sufficient fire resistance performance.

Examples of the thermal stabilization aid include epoxidized soybean oil, phosphate ester, polyol, hydrotalcite, zeolite, and the like.
Examples of the light stabilizer include hindered amine light stabilizers.
Examples of the ultraviolet absorber include salicylic acid ester ultraviolet absorbers, benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, and cyanoacrylate ultraviolet absorbers.

Examples of pigments include organic pigments such as azo pigments, phthalocyanine pigments, threne pigments, and dye lake pigments; oxide pigments, molybdenum chromate pigments, sulfide/selenide pigments, and ferrocyanide pigments. Inorganic pigments such as

Examples of the plasticizer include dibutyl phthalate, di-2-ethylhexyl phthalate, di-2-ethylhexyl adipate, and the like. However, since plasticizers tend to reduce the heat resistance and fire resistance of molded articles, it is preferable that the amount of plasticizers used is small.

Examples of thermoplastic elastomers include acrylonitrile-butadiene copolymer (NBR), ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl acetate-carbon monoxide copolymer (EVACO), and vinyl chloride-vinyl acetate copolymer. Polymers, vinyl chloride thermoplastic elastomers such as vinyl chloride-vinylidene chloride copolymers, styrene thermoplastic elastomers, olefin thermoplastic elastomers, urethane thermoplastic elastomers, polyester thermoplastic elastomers, polyamide thermoplastic elastomers, etc. can be mentioned.

The thermal expansion start temperature of the thermally expandable graphite contained in the resin composition (B) is preferably 200°C or more and 285°C or less, more preferably 210°C or more and 285°C or less, and even more preferably 240°C or more and 285°C or less. The tube 30 can be formed into a tubular shape by extruding a resin composition using a mold, for example. At this time, the resin composition flows around in the circumferential direction within the mold. Therefore, a weld line extending in the axial direction of the tube 30 is formed at a position where the resin composition wraps around and abuts against each other. If the thermal expansion start temperature is equal to or higher than the above lower limit value, the temperature at which the tube 30 is extruded using a mold can be raised during manufacture, so that the tubes are brought into close contact with each other at the weld line and the compressive strength can be further increased. In addition, if the thermal expansion start temperature is equal to or higher than the above lower limit value, gas generation due to expansion of thermally expandable graphite is suppressed during manufacture of the tube 30, and good adhesion at the weld line is achieved, thereby increasing the compressive strength. be enhanced.
In addition, the thermal expansion start temperature of thermally expandable graphite is 1.1 times or more the volume before heating starts when the thermally expandable graphite is heated from 150°C at a heating rate of 5°C/min. This is the temperature at which it expands. The temperature interval at which the volume of the thermally expandable graphite is measured is not particularly limited, and for example, the volume may be measured every time the temperature rises by 5°C.
The thermal expansion start temperature equal to or higher than the lower limit is sufficiently higher than the molding temperature at which the pipe 30 is produced by molding the resin composition (B). Therefore, when the thermal expansion start temperature of the thermally expandable graphite is equal to or higher than the lower limit value, it is possible to prevent the thermally expandable graphite from expanding when molding the resin composition (B).

Thermally expandable graphite is flake-like graphite and has a flat plate shape. Since the thermally expandable graphite is in the form of scales, it can be sufficiently expanded by heating. Note that the scaly shape refers to a thin piece or a flat plate shape, and for example, the aspect ratio described below is 5 or more.

Further, the degree of expansion of the thermally expandable graphite at 1000° C. is preferably 180 cm ³ /g or more, more preferably 185 cm ³ /g or more. Here, the degree of expansion of thermally expandable graphite at 1000°C is the volume (cm ³ ) per unit mass (g) of thermally expandable graphite after it is held at 1000°C for 10 seconds.
If the degree of expansion of the thermally expandable graphite is greater than or equal to the lower limit value, the thermally expandable graphite will expand sufficiently, so that the compartment penetration portion 2a can be more reliably closed in the event of a fire.
The degree of expansion of the thermally expandable graphite at 1000° C. is preferably 240 cm ³ /g or less from the viewpoint of facilitating the manufacture of the thermally expandable graphite.

Thermally expandable graphite as described above can be obtained by treating graphite powder with an inorganic acid and an oxidizing agent. Through this treatment, a crystalline compound in which an inorganic acid is inserted between graphite layers can be obtained. A crystalline compound in which an inorganic acid is inserted between layers of graphite has thermal expandability.
Examples of the graphite include natural scale graphite, pyrolytic graphite, and quiche graphite.
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, dichromate, hydrogen peroxide, and the like.
After treating the graphite powder with the inorganic acid and the oxidizing agent, a neutralization treatment may be performed to reduce the acidity.

The pH of the thermally expandable graphite is preferably 2 or more and 10 or less, more preferably 2.5 or more and 8 or less. When the resin composition (B) contains a heat absorbing agent having hydroxide ions, such as magnesium hydroxide or aluminum hydroxide, as a flame retardant, the hydroxide ions of the flame retardant are neutralized with acidic substances to form water. (neutralized water) is produced. Since the hydroxide ions used in the endothermic condensation reaction of hydroxide ions are reduced by the neutralization reaction during molding, the amount of heat absorbed in the event of a fire is reduced. In addition, air bubbles may be generated due to evaporation of the neutralized water. Therefore, neutralization with the flame retardant can be suppressed by setting the pH of the thermally expandable graphite to the above lower limit or more. If the pH of the thermally expandable graphite is below the above upper limit, the thermally expandable graphite will be less likely to be neutralized and will expand better.
The method for adjusting the pH of thermally expandable graphite is not particularly limited. For example, when producing thermally expandable graphite, there is a method in which graphite powder is treated with an inorganic acid and an oxidizing agent, and then washed with water and dried repeatedly to adjust the pH of the thermally expandable graphite.
The pH of thermally expandable graphite is a value measured by the following method.
5 g of the collected thermally expandable graphite and 25 ml of ion-exchanged water are placed in a beaker to prepare a graphite mixture. The prepared graphite mixture is stirred for 30 seconds, left to stand for 20 minutes, and then the pH of the graphite mixture is measured using a pH meter (Horiba, Ltd. "pH/ION METER F-23").

The average particle diameter of the thermally expandable graphite is preferably 10 μm or more and 1000 μm or less, more preferably 100 μm or more and 700 μm or less. Moreover, it is preferable that the average thickness is 100 μm or less.
The average particle size of the thermally expandable graphite is the 50% particle size in the volume-based cumulative particle size distribution, which is determined by sieving the thermally expandable graphite using a JIS Z8801-1 test sieve.

The average aspect ratio of the thermally expandable graphite is 5 or more and 40 or less, preferably 10 or more and 35 or less, and more preferably 20 or more and 35 or less. That is, the thermally expandable graphite is a flat flake. If the aspect ratio is greater than or equal to the above lower limit, the degree of expansion tends to be low. If the aspect ratio is less than or equal to the above upper limit, the thermal conductivity can be further reduced. In addition, if the aspect ratio is equal to or less than the above upper limit, when the tube 30 has a multilayer structure, the difference in linear expansion coefficient between a layer containing thermally expandable graphite and a layer not containing thermally expandable graphite can be reduced, and the tube 30 Suppress molding defects such as peeling of the intermediate layer and surface layer due to differences in shrinkage caused by internal cleaning or heat from high-temperature wastewater, or warping of the tube 30 due to a large difference in shrinkage between the surface layer and intermediate layer after molding. can.
The thermally expandable graphite, which is a flat plate-shaped flake, is oriented along the circumferential direction of the tube 30. At the weld line, the thermally expandable graphite tends to be oriented in the radial direction of the tube 30. Therefore, at the position of the weld line, the flat surfaces of the thermally expandable graphite face each other, and cracks are likely to occur. If the aspect ratio is below the above upper limit, the area of opposing thermally expandable graphite at the weld line becomes small, and the compressive strength can be increased.

The linear expansion coefficient of the hard polyvinyl chloride resin constituting the tube 30 is 7.0 x 10 ^-5 /°C as measured by thermomechanical analysis method (TMA method) specified in JIS K 7197:2012. However, the tube 30 of this embodiment has a temperature of 4.5×10 ⁻⁵ /°C or more and less than 7.0×10 ⁻⁵ /°C, and a temperature of 5.0×10 ⁻⁵ /°C or more and 7.0×10 ⁻ It is preferably less than ⁵ x 10 -5 /°C, more preferably 5.5 x 10 ^-5 /°C or more and less than 6.8 x 10 ^-5 /°C. Furthermore, the difference in linear expansion coefficient between the surface layer, inner layer, and intermediate layer is 2.5×10 ⁻⁵ /°C or less, preferably 2.0×10 ⁻⁵ /°C or less, and 1.0×10 ⁻⁵ /°C or less. C or less is more preferable.

Furthermore, the fusion strength between the surface layer and inner layer of the tube 30 and the intermediate layer is preferably 1.5 MPa or more, more preferably 2.0 MPa or more. The higher the fusion strength, the easier it is to increase the compressive strength of the tube 30. The fusion strength between the surface layer, the inner layer, and the intermediate layer can be adjusted by a combination of the aspect ratio of the thermally expandable graphite, the amount of the thermally expandable graphite, and the degree of vacuum in the sizing device in the manufacturing method described below.

The average aspect ratio is the ratio of the longest length in plan view to the thickness. Since the thermally expandable graphite used in the present invention has a generally flat plate shape, if the thickness direction is considered to be the vertical direction and the radial direction is considered to be the horizontal direction, the maximum dimension in the horizontal direction is the thickness in the vertical direction. The divided value is the aspect ratio.

Then, the aspect ratio is measured for a sufficiently large number of graphite pieces, that is, at least 10 graphite pieces, and the average value is taken as the average aspect ratio. More specifically, we observed thermally expandable graphite using FE-SEM, loaded the image into image processing software (Adobe Systems Incorporated "Photoshop (registered trademark)"), and measured the maximum size using a length measurement tool. Measure the dimensions and thickness. Regarding the maximum dimension, when measuring graphite particles before being added to the resin composition, the maximum dimension is the maximum side of a quadrangle circumscribing the graphite particles. When measuring the maximum dimension of graphite particles after being added to the resin composition, either cut the tube 30 and observe the cross section and determine the longest side as the maximum dimension, or extract the graphite particles from the tube 30 and The maximum side of the rectangle circumscribing the graphite particle. Note that specific dimensions can be measured by measuring the length of the scale bar in the FE-SEM image in the same manner.

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

The content of thermally expandable graphite in the resin composition (B) is preferably 3.0 parts by mass or more and 20.0 parts by mass or less, and 4.0 parts by mass or more and 18.0 parts by mass based on 100 parts by mass of the thermoplastic resin. parts by weight or less, more preferably 4.0 parts by weight or more and 15.0 parts by weight or less, particularly preferably 4.0 parts by weight or more and less than 10.0 parts by weight. If the content of thermally expandable graphite in the resin composition (B) is equal to or higher than the lower limit value, the pipe 30 (especially the second vertical pipe 32) can be sufficiently expanded in the event of a fire, and the compartment penetration portion The fire resistance in 2a can be further improved. On the other hand, if the content of thermally expandable graphite in the resin composition (B) is below the upper limit, it is possible to prevent the pipe 30 from expanding excessively, thereby preventing the pipe 30 from breaking and reducing its fire resistance. In addition, if the content of thermally expandable graphite in the resin composition (B) is below the above upper limit, the thermal conductivity of the tube 30 can be lowered and the pressure resistance and compressive strength can be further increased.

Moreover, it is preferable that the resin composition (B) contains a flame retardant in addition to thermally expandable graphite. The flame retardant in the resin composition (B) is a compound that has an endothermic action and suppresses a temperature rise when heated, or a compound that melts upon heating and suppresses supply of oxygen and generation of combustible gas. For example, an endothermic agent can be used as a flame retardant, which is a compound that causes an endothermic reaction such as a dehydration reaction when heated.
Examples of endothermic agents include magnesium hydroxide, aluminum hydroxide, inorganic hydroxides such as kaolin minerals (kaolinite, halloysite, dickite) and hydrotarsalcite, sepiolite, bentonite, montmorillonite, talc, mica, quartz, Examples include inorganic compounds with water-absorbing properties such as zeolite, wollastonite, and nepheline cyanite. Hereinafter, inorganic hydroxides and inorganic compounds that undergo a dehydration reaction when heated are collectively referred to as "heat-dehydrated compounds." In heat-dehydrated compounds, temperature rise can also be suppressed by the latent heat of vaporization of water generated by the dehydration reaction.
Among heat-dehydrated compounds, magnesium hydroxide undergoes a dehydration reaction at temperatures above 300°C. can suppress the occurrence of dehydration reactions.
Among heat-dehydrated compounds, aluminum hydroxide undergoes a dehydration reaction at about 200°C, so when aluminum hydroxide is used as a flame retardant, the heat transferred to the pipe 30 in the event of a fire can be quickly absorbed. I can do it.

Among heat-dehydrated compounds, hydrotalcite, whose chemical name is magnesium aluminum hydroxide carbonate hydrate, is a type of mineral represented by Mg ₆ Al ₂ (OH) ₁₆ CO ₃ 4H ₂ O, etc. It is a layered inorganic compound consisting of a 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- . be. Many divalent and trivalent metals have layered structures similar to this, and these are represented by the following general formula.
[M ²⁺ _1-x M ³⁺ _x (OH) ₂ ] ^x+ [A ^n- _x/n・mH 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⁺ A ^n- : n-valent anion such as CO ₃ ^2- , Cl ^- , NO ₃ ^-, etc. X: 0<X≦0.33
Hydrotalcite starts dehydrating the water of crystallization that it has between molecules at about 180°C, and the water of crystallization is completely eliminated at about 300°C. Until this state, synthetic hydrotalcite maintains its crystalline structure, but when the temperature exceeds about 350°C, the crystalline structure begins to collapse and releases water and carbon dioxide. Synthetic hydrotalcite starts endothermic decomposition at a temperature lower than the thermal decomposition temperature of vinyl chloride resin, which is approximately 200°C or more and 300°C or less, by 60°C or more and 75°C or less. can be effectively suppressed by endothermic decomposition of hydrotalcite.
As the flame retardant, at least two of magnesium hydroxide, aluminum hydroxide, kaolin mineral, or hydrotalcite may be used in combination.

The heat-dehydrated compound is usually in the form of particles.
The volume average particle diameter of the heat-dehydrated compound is preferably 0.01 μm or more and 20 μm or less, more preferably 0.05 μm or more and 2 μm or less, and even more preferably 0.05 μm or more and 1 μm or less. By setting the volume average particle diameter of the heat-dehydrated compound within this range, transparency can be imparted to the tube 30 and the dispersibility of the heat-dehydrated compound can be improved. The volume average particle size is a value measured using a laser diffraction scattering particle size distribution measuring device.
The BET specific surface area of the heat-dehydrated compound is preferably 1 m ² /g or more and 40 m ² /g or less, and preferably 1 m ² /g or more and 20 m ² /g or less. Here, the BET specific surface area is a value determined using nitrogen adsorption.
If the volume average particle diameter and BET specific surface area of the heat-dehydrated compound are within the above ranges, the effect as a flame retardant can be sufficiently exhibited, and the moldability and moldability of the resin composition (B) when producing the pipe 30 are improved. Sufficient mechanical properties of the pipe 30 can be ensured.

The particle surface of the heat-dehydrated compound is preferably surface-treated with a higher fatty acid such as stearic acid or a surface treatment agent such as a silane coupling agent. A heat-dehydrated compound that has been surface-treated with a surface treatment agent has a higher dispersibility in a thermoplastic resin, and is more likely to exhibit an endothermic effect. Furthermore, when the heat-dehydrated compound is basic, it can make the thermoplastic resin less prone to fading and prevent yellowing.
When the heat-dehydrated compound is surface-treated with a surface treatment 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 based on 100 parts by mass of the heat-dehydrated compound. When the amount of the surface treatment agent is at least the above lower limit, the dispersibility of the heat-dehydrated compound in the thermoplastic resin can be sufficiently increased, and when it is at most the above upper limit, a decrease in economic efficiency can be suppressed.

Examples of flame retardants other than endothermic agents include hydrotalcite, antimony oxide, molybdenum compounds, bromine compounds, phosphorus compounds, and boric acid compounds.
Examples of antimony oxide include antimony dioxide, antimony trioxide, and antimony pentoxide.
Examples of molybdenum compounds include molybdenum trioxide, molybdenum disulfide, ammonium molybdate, and the like.
Examples of the brominated compound include tetrabromobisphenol A, tetrabromoethane, tetrabromoethane, and tetrabromoethane.
Phosphorus compounds include red phosphorus, triphenyl phosphate, tricresyl phosphate, tricylenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, sodium phosphate, potassium phosphate, magnesium phosphate, zinc phosphate, Examples include ammonium polyphosphate.
Examples of boric acid compounds include calcium borate, zinc borate, and the like.
Among the flame retardants, phosphorus compounds and antimony trioxide are preferred because they have a high effect of suppressing the combustion of polyvinyl chloride resin.
These flame retardants may be used alone or in combination of two or more.

As the flame retardant in the resin composition (B), heat-dehydrated compounds such as aluminum hydroxide, magnesium hydroxide, and magnesium carbonate, molybdenum compounds, bromine compounds, phosphorus compounds, and boric acid compounds are preferable. When these flame retardants are included, the fire resistance performance of the pipe 30 can be further improved.
The content of the flame retardant in the resin composition (B) is preferably 0.05 parts by mass or more and 10 parts by mass or less, and more preferably 1 part by mass or more and 5 parts by mass or less, based on 100 parts by mass of the thermoplastic resin.
Further, the content of the flame retardant is preferably 13 parts by mass or more and 215 parts by mass or less, more preferably 13 parts by mass or more and 190 parts by mass or less, and 17 parts by mass or less, based on 100 parts by mass of thermally expandable graphite contained in the thermoplastic resin. It is more preferably 40 parts by mass or more and 120 parts by mass or less, and most preferably 40 parts by mass or more and 120 parts by mass or less.
If the content of the flame retardant is at least the lower limit, the fire resistance can be further improved, and if the content is at least the upper limit, the mechanical strength of the pipe 30 can be sufficiently increased.
In particular, when part or all of the flame retardant is a phosphorus compound, the mechanical strength tends to decrease, so the content of the phosphorus compound is determined based on 100 parts by mass of thermally expandable graphite contained in the thermoplastic resin. , is preferably 1 part by mass or more and less than 200 parts by mass, and more preferably 13 parts by mass or more and 150 parts by mass or less.

The volume average particle diameter of the flame retardant is preferably 0.2 μm or more and 100 μm or less, more preferably 0.4 μm or more and 50 μm or less. The volume average particle diameter of the flame retardant is a value measured with a light scattering particle size meter (Light scattering particle size meter DLS-7000: manufactured by Otsuka Electronics Co., Ltd.).
When the resin composition (B) contains a flame retardant, the ratio between the average particle diameter α of the thermally expandable graphite and the volume average particle diameter β of the flame retardant (β/α ratio) is 0.0015 or more and 0.0065. The following is preferable, and 0.002 or more and 0.006 or less are more preferable. The flame retardant acts as a thermal bridge between the thermally expandable graphites. If the β/α ratio is within the above range, the above thermal bridging can be prevented and the thermal conductivity can be further lowered.

The resin composition (B) may contain a heat stabilizer. Examples of the heat stabilizer include lead-based stabilizers, tin-based stabilizers, Ca--Zn-based stabilizers, higher fatty acid metal salts, and the like. One type of heat stabilizer may be used alone, or two or more types may be used in combination.

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

The content of the heat stabilizer is preferably 0.3 parts by mass or more and 5.0 parts by mass or less based on 100 parts by mass of the thermoplastic resin. If the content of the heat stabilizer is above the lower limit, it can improve the thermal stability of the thermoplastic resin during molding, and if it is below the lower limit, the thermoplastic resin can be sufficiently carbonized during combustion. It is possible to obtain sufficient fire resistance performance.

It is preferable that the resin composition (B) contains an inorganic filler in addition to thermally expandable graphite.
Inorganic fillers include inorganic compounds other than the flame retardants, 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, zinc carbonate, barium carbonate, dawnite, hydrotalcite, calcium sulfate, barium sulfate, gypsum fiber, calcium silicate, talc, clay, mica, montmorillonite, bentonite, activated clay, sepiolite, imogolite , sericite, glass fiber, glass beads, silica balloons, aluminum nitride, boron nitride, silicon nitride, carbon black, graphite, carbon fiber, carbon balloons, charcoal powder, various metal powders, potassium titanate, magnesium sulfate, titanic acid Examples include lead zirconate, aluminum borate, molybdenum sulfide, silicon carbide, stainless steel fibers, zinc phosphate, zinc borate, various magnetic powders, slag fibers, fly ash, and dehydrated sludge. Among the inorganic fillers, basic inorganic fillers such as calcium carbonate, calcium silicate, calcium hydroxide, calcium oxide, magnesium oxide, barium carbonate, zinc oxide, zinc hydroxide, and iron oxide are preferred.
The inorganic fillers may be used alone or in combination of two or more.

The content of the inorganic filler is preferably 0.3 parts by mass or more and 50.0 parts by mass or less, and 1.0 parts by mass or more and 5.0 parts by mass or less, based on 100 parts by mass of the thermoplastic resin. It is more preferable. If the content of the inorganic filler is equal to or greater than the lower limit, the fire resistance can be further improved, and if the content is equal to or less than the upper limit, the mechanical strength of the pipe 30 can be made sufficiently high.
In particular, when using thermally expandable graphite whose pH is adjusted to 1.5 or more and 4.0 or less, the basic inorganic filler is added to the resin composition (B) by 100% by mass of the thermoplastic resin. It is preferably contained in a proportion of 0.3 parts by mass or more and 5.0 parts by mass or less. If the content ratio of the basic inorganic filler is equal to or higher than the lower limit value, the thermal stability of molding the resin composition (B) to produce the tube 30 will be high, and generation of carbides during molding can be prevented, and the content ratio will exceed the upper limit value. If it is below this value, the thermoplastic resin can be sufficiently carbonized in the event of a fire, and the fire resistance can be further improved.

As explained above, according to the joint 20 according to the present embodiment, the axial rigidity of the sound insulation cover 22 is equal to the bending resistance measured in accordance with JIS L-1096:2010 (45° cantilever method). The length is 13 cm or more and less than 40 cm. Therefore, the sound insulating cover 22 has sufficient rigidity in the axial direction. Thereby, the spacer between the joint body 21 and the sound insulation cover 22 can be eliminated, or even if a spacer is provided, the spacer can be minimized. Therefore, even if the joint body 21 is heated for some reason, overheating of the joint body 21 due to the spacer is suppressed.

When the sound insulation cover 22 is made of soft vinyl chloride resin as in the conventional joint, it is necessary to add a plasticizer to the soft vinyl chloride resin in order to adjust the rigidity of the sound insulation cover 22.
In the joint 20 of this embodiment, the sound insulation cover 22 is preferably made of olefin resin. In this case, unlike the case where the sound insulation cover 22 is made of soft vinyl chloride resin, it is not necessary to add a plasticizer to the olefin resin (sound insulation cover 22).
Here, if a plasticizer is added to the sound insulation cover 22, the plasticizer will migrate to other members that are in contact with the sound insulation cover 22. Examples of the other members include the joint body 21. Examples of the other members include, for example, the tape 25 that fixes the sound insulating cover 22 to the joint body 21.
In order to restrict migration of the plasticizer to the joint body 21, it is conceivable to provide a nonwoven fabric layer between the joint body 21 and the sound insulating cover 22. However, in this case, heat tends to accumulate in the space S between the joint 20 and the sound insulation cover 22 due to the nonwoven fabric layer.
When the plasticizer migrates to the tape 25 described above, the adhesiveness of the tape 25 decreases, and there is a risk that the tape 25 will peel off and the sound insulating cover 22 will also peel off from the joint body 21.
Therefore, as in the present embodiment, when the sound insulation cover 22 does not contain a plasticizer, heat does not easily accumulate in the space S between the joint 20 and the sound insulation cover 22, and heat is not easily trapped in the space S between the joint 20 and the sound insulation cover 22, and the heat is not easily trapped in the space S between the joint 20 and the sound insulation cover 22. Peeling can also be suppressed.

At least a portion of the space S between the joint body 21 and the sound insulation cover 22 in the axial direction is annular and continuous in the circumferential direction of the joint body 21 . Therefore, heat can be caused to convect in the circumferential direction within the space S.

Note that the technical scope of the present invention is not limited to the embodiments described above, and various changes can be made without departing from the spirit of the present invention.

The materials of the joint body 21, the sound insulation cover 22, and the pipe 30 are not limited to those shown in the above embodiments.
The space S does not have to be continuous in the circumferential direction.

In addition, without departing from the spirit of the present invention, the components in the embodiments described above may be replaced with well-known components as appropriate, and the above-described modifications may be combined as appropriate.

The next verification test for verifying the effects of the above embodiment is shown below.
In this verification test, a total of 10 types of joints 20 of Examples 1 to 6 and Comparative Examples 1 to 4 were prepared. The joint 20 is made of hard polyvinyl chloride resin specified in JIS K 6739, has a nominal diameter of 125 (inner diameter of the socket is 140 mm), and has a large 90° bend Y (LT). The external shapes of Examples 1 to 6 and Comparative Examples 1 to 4 are similar to the joint 20 according to the embodiment described based on FIGS. 1 and 2. The areal density of the sound insulation cover 22 of each of these joints 20, the thickness of the sound insulation cover 22, the presence or absence of a spacer, each configuration of rigidity, and the results of the fire resistance evaluation are shown in Tables 1 and 2 below.

(rigidity)
The rigidity (TD) in Table 1 is the rigidity in the orthogonal direction TD (Transvers Direction) of the original fabric 50 of the sound insulation cover 22, in other words, the rigidity in the lateral direction B of the sound insulation cover 22 (the rigidity in the vertical direction Z of the sound insulation cover 22). ). The rigidity (MD) is the rigidity in the extrusion direction MD (Machine Direction) of the original fabric 50 of the sound insulation cover 22, in other words, the rigidity in the longitudinal direction A of the sound insulation cover 22. Here, for the measurement of each rigidity in this verification test, three samples 60 satisfying the above-mentioned conditions were obtained from the original fabric 50 of the sound insulation cover 22 instead of acquiring the samples 60 from the sound insulation cover 22.

(Workability)
A worker attached the sound insulation cover 22 to the joint body 21 by hand, and fixed the sound insulation cover 22 with tape so that the end faces of both ends in the longitudinal direction A were facing each other, thereby manufacturing the joint 20. The presence or absence of a gap between both ends of the sound insulating cover 22 of the manufactured joint 20 and peeling of the tape was evaluated, and those with gaps or peeling were rated as ×, and those without were rated as ○.

(Fire resistance)
A fire resistance test furnace 100 shown in FIG. 6 was used for the fire resistance evaluation. The fireproof test furnace 100 includes a heating chamber 110 that is sealed except for the upper part, a floor slab 120 for testing installed on the heating chamber 110, and a burner 130 that is installed in the heating chamber 110 and generates a flame. A thermocouple 140 is provided to measure the temperature inside the heating chamber 110. As the floor slab 120, a 100 mm thick PC (precast concrete) panel was used in which a compartment penetration portion 120a with a diameter of 260 mm was formed. The thermocouple 140 was arranged so as to be able to measure the temperature near the lower end of the second vertical tube 32 inside the heating chamber 110. Additionally, mortar 3 was filled between the joint 20 and the inner surface of the section penetrating section 120a to seal the section penetrating section 120a.
A piping structure 10 was installed in this fireproof test furnace 100 in the same arrangement as in the above embodiment.
Then, a fire resistance test (according to ISO 834-1, the evaluation method for fire resistance performance tests of the Revised Building Standards Act enforced on June 1, 2000) was conducted. In this fire resistance test, the time required for smoke to emerge from the gap between the joint 20 and the compartment penetration portion 120a after the start of heating (smoke generation time) was measured. According to the criteria for Section 8 of the Fire Service Act, if the smoke generation time is 120 minutes or more, it is considered fire resistant and the evaluation in Table 3 is ``○'', and if it is less than 120 minutes, it is considered not fire resistant and the evaluation in Table 3 is `` ×”.

From the above results, in the piping structures 10 of Examples 1 to 6, smoke does not flow out from between the joint 20 and the compartment penetration part 120a even after 120 minutes from the start of heating, and the piping structures 10 have fire resistance. It was confirmed that In addition, even after the sound insulation cover 22 was attached to the joint body 21, no peeling or gaps occurred, and the joint 20 could be manufactured. On the other hand, in the piping structures 10 of Comparative Examples 1 and 3, smoke generation was observed within 120 minutes from the start of heating. In Comparative Examples 2 and 4, the rigidity of the sound insulation cover 22 was too high, so the sound insulation cover 22 could not be attached to the joint body 21 without gaps or tape peeling, and it was not possible to manufacture a joint 20 that could perform a fire resistance test. .

20 Joint 21 Joint body 22 Sound insulation cover 23 Main pipe 24 Socket 30 Pipe S Space

Claims (4)

The joint body,
a resin sound insulating cover that covers the joint body from the outside in the radial direction of the joint body,
A space is provided between the joint body and the sound insulation cover,
When the rigidity of the sound insulation cover is defined as bending resistance (cm) measured in accordance with JIS L-1096:2010 (45° cantilever method), the rigidity of the sound insulation cover is 13 cm or more and less than 40 cm. Fittings. The joint according to claim 1, wherein the sound insulation cover is made of olefin resin containing no plasticizer. The joint according to claim 1 or 2, wherein at least a portion of the space in the axial direction of the joint body has an annular shape continuous in the circumferential direction of the joint body. The joint body is
a main pipe extending in the axial direction of the joint body;
two sockets arranged at both ends of the main pipe in the axial direction,
The outer diameter of the main pipe is smaller than the outer diameter of the two sockets,
Both ends of the sound insulation cover in the axial direction are fixed to each of the two sockets,
The joint according to any one of claims 1 to 3, wherein the space is provided between the main pipe and the sound insulation cover.

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