JP7184580B2 - Expansion joints and expansion pipe structures - Google Patents

Description

TECHNICAL FIELD The present invention relates to an expansion joint and an expansion pipe structure into which a pipe member that expands and contracts with changes in temperature is inserted.

As is well known, piping members applied to vertical pipes for flowing water from the upper floors to the lower floors of buildings are generally large in size and are subject to seasonal factors and temperature changes in the water flowing inside. The total length of the piping member changes greatly.

Therefore, even if the piping member applied to the vertical pipeline expands and contracts, the water in the vertical pipeline flows stably without leaking to the outside. is inserted into the socket of the joint, and even if the pipe member expands and contracts, the lower pipe end moves inside the joint to suppress the water inside the pipe from leaking from the joint (for example, an insertion A telescopic piping structure with a socket) is widely used (see, for example, Non-Patent Document 1 (P99, plug-in socket).)

By the way, in a building or the like, a large number of air conditioners are installed on each floor, and it is common to provide a drain pipe to discharge the drain (condensed water) generated by the air conditioners.
In such a drain pipe, the drain generated by the air conditioners on each floor is collected in the horizontal pipe line portion, and the collected drain is discharged to the lower floors by the vertical pipe line portion.

In an expandable piping structure for flowing drain generated in such an air conditioner, for example, as shown in FIG. The heat insulating pipes 520 and 530 formed with 523 and 533 are applied as vertical pipes and inserted into the joint 510 .

However, in such an expansion pipe structure, when the vertical pipe contracts due to a change in temperature, low-temperature water flowing inside directly contacts the inner surface of the joint (expansion joint) 510, cooling the outer surface of the joint 510 and causing condensation.
Therefore, when the drainage generated by the air conditioner is allowed to flow, it is common to wrap a heat insulating material (heat insulating material) or heat insulating material tape 540 around the outer peripheral surface of the joint to form an expansion pipe structure 500 that can prevent dew condensation. .

URL: http://www.sekisui-kenzai.com/common/pdf/amatoi_building/ltk1299_1303_18.pdf

However, the work of wrapping heat insulating material, heat insulating tape, etc. around the outer peripheral surface of the expansion joint must be done on site after constructing the expansion pipe structure, which is time-consuming and leads to an extension of the construction period. In addition, there is a problem that skill is required for construction, and the heat insulating material wrapped around the outside is likely to deteriorate over time and is difficult to maintain for a long period of time due to falling off or the like.

SUMMARY OF THE INVENTION The present invention has been made in consideration of such circumstances, and provides an expansion joint capable of suppressing condensation on the outer surface of the expansion joint even when a piping member inserted into the expansion joint expands and contracts. The object is to provide a piping structure.

In order to solve the above problems, the present invention proposes the following means.
According to the first aspect of the invention, there is provided a joint main body having a barrel formed in a cylindrical shape, and a receptacle formed at a first end of the joint main body, wherein the receptacle is provided with a piping member. is inserted into the pipe end, and the pipe end can be expanded and contracted along the pipe axis direction of the joint body, and foamed resin is embedded over the entire circumference inside the body. and a burr removal trace is formed over the entire length of the range in which the foamed resin layer is embedded in the pipe axis direction of the joint body.

According to the expansion joint according to the present invention, since the foamed resin layer in which the foamed resin is embedded is provided over the entire circumference of the inside of the body, the low-temperature water that flows through the piping member when the piping member shrinks and the expansion joint. Even with direct contact, cooling of the outer surface of the expansion joint is suppressed.
As a result, it is possible to suppress dew condensation on the outer surface of the expansion joint even if the piping member inserted into the expansion joint expands and contracts.
According to the expansion joint of the present invention, the burr-removed marks are formed over the entire length of the range in which the foamed resin layer is embedded in the axial direction of the pipe. The foamed resin layer can be stably embedded in the entire circumference inside the trunk over the entire length.
In addition, it is possible to efficiently inspect whether or not the foamed resin layer is formed on the entire circumference inside the body over the entire length of the range in which the foamed resin layer is embedded.
In addition, by easily confirming the range in which the foamed resin layer is formed at the time of piping construction, construction can be efficiently performed.

The invention according to claim 2 is the expansion joint according to claim 1, wherein the foamed resin layer moves the pipe end of the pipe member as the pipe member inserted into the socket expands and contracts. It is formed over the entire length of the joint body in the pipe axis direction.

According to the expansion joint according to the present invention, the foamed resin layer is formed over the entire length in the pipe axial direction along which the pipe end of the pipe member moves as the pipe member expands and contracts. Thermal conduction of the heat of low-temperature water to the outside of the expansion joint is suppressed by the heat insulating layer of the piping member or the foamed resin layer of the expansion joint.
As a result, dew condensation on the outer surface of the expansion joint can be reliably suppressed.

The invention according to claim 3 is the expansion joint according to claim 1 or 2 , wherein the joint body has a trunk portion with a thickness of 6.5 mm or more and 13 mm or less, and the foamed resin layer has a thickness of 6.5 mm or more and 13 mm or less. is formed to be 50% or more and 85% or less of the thickness of the trunk portion.

According to the expansion joint according to the present invention, the thickness of the body is formed to be 6.5 mm or more and 13 mm or less, and the thickness of the foamed resin layer is formed to be 50% or more and 85% or less of the thickness of the body. Therefore, the heat insulating effect can be efficiently secured.
Also, conventional piping members and fittings can be used efficiently.

The invention according to claim 4 is an expansion pipe structure, comprising: the expansion joint according to any one of claims 1 to 3 ; An end portion is inserted into the joint body, and the pipe end portion can be expanded and contracted along the pipe axis direction of the joint body.

According to the expansion pipe structure according to the present invention, the expansion joint includes the foamed resin layer in which the foamed resin is embedded over the entire circumference of the inside of the body of the joint body. Even if the flowing cold water comes into direct contact with the expansion joint, the outer surface of the expansion joint is inhibited from being cooled.
As a result, it is possible to suppress dew condensation on the outer surface of the expansion joint even if the piping member inserted into the expansion joint expands and contracts.

According to the expansion joint and the expansion pipe structure according to the present invention, it is possible to suppress dew condensation on the outer surface of the expansion joint even if the piping member inserted into the expansion joint expands and contracts.

BRIEF DESCRIPTION OF THE DRAWINGS It is a longitudinal cross-sectional view explaining schematic structure of the expansion-and-contraction piping structure which concerns on 1st Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view explaining schematic structure of the expansion joint which concerns on 1st Embodiment. FIG. 3 is a vertical cross-sectional view taken along line III-III in FIG. 2 for explaining an example of the schematic configuration of the expansion joint according to the first embodiment. It is a figure explaining the outline of an effect|action of the expansion-and-contraction piping structure which concerns on 1st Embodiment, and is a conceptual diagram which shows the state which the upper vertical piping contracted. It is a figure explaining the outline of the effect|action of the expansion-and-contraction piping structure which concerns on 1st Embodiment, and is a conceptual diagram which shows the state in which the upper vertical piping was extended. It is a figure explaining the manufacturing method of the expansion joint which concerns on 1st Embodiment, and is a longitudinal cross-sectional view explaining schematic structure of an injection molding die. FIG. 4B is a diagram for explaining the outline of the method for manufacturing the expansion joint according to the first embodiment, and is a conceptual diagram showing a cross section of the trunk of the expansion joint seen along the pipe axis direction in the first injection step. FIG. 4B is a diagram for explaining the outline of the method for manufacturing the expansion joint according to the first embodiment, and is a conceptual diagram showing a cross section of the trunk of the expansion joint seen along the pipe axis direction in the second injection step. Fig. 10 is a perspective view illustrating a schematic configuration of an expansion joint according to a second embodiment of the present invention; FIG. 11 is a perspective view illustrating a schematic configuration of an expansion joint according to a third embodiment of the present invention; It is a longitudinal section explaining a schematic structure of the conventional expansion joint.

<First embodiment>
An expansion pipe structure and an expansion joint according to a first embodiment of the present invention will be described below with reference to FIGS. 1 to 4. FIG.
FIG. 1 is a vertical cross-sectional view illustrating a schematic configuration of an expansion pipe structure according to a first embodiment of the present invention. Moreover, FIG. 2 is a perspective view explaining a schematic structure of the expansion joint which concerns on 1st Embodiment, and FIG. 3 is a longitudinal cross-sectional view explaining a schematic structure of an expansion joint. In the figure, reference numeral 100 indicates an expansion pipe structure, reference numeral 10 indicates an expansion joint, reference numeral 110 indicates an upper vertical pipe (piping member), and reference numeral 120 indicates a lower vertical pipe.

The expansion/contraction pipe structure 100 includes, for example, an expansion joint 10, a seal member 20, an upper vertical pipe (piping member) 110, and a lower vertical pipe 120, as shown in FIG.
In this embodiment, the expansion/contraction pipe structure 100 is, for example, a drain pipe that allows drain generated by an air conditioner to flow from the upper floors of the building toward the lower floors.

The upper vertical pipe (pipe member) 110 includes an outer wall portion 11A forming an outer peripheral surface, an inner wall portion 11B forming an inner peripheral surface, and a heat insulating layer 11C formed between the outer wall portion 11A and the inner wall portion 11B. . The upper vertical pipe (pipe member) 110 has its pipe end inserted into the socket 11H on the upper side (first pipe end) of the expansion joint 10 via the seal member 20, and the pipe end 110T is inserted into the joint 10 It is possible to expand and contract in the direction of arrow T along the direction of tube axis O.

The outer wall portion 11A and the inner wall portion 11B are formed of hard non-foamed resin layers made of non-foamed resin such as polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer (ABS resin), polyethylene, and polypropylene.
Also, the heat insulating layer 11C is formed of a foamed resin layer such as polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer (ABS resin), polyethylene, polypropylene, or the like.
The materials of the outer wall portion 11A, the inner wall portion 11B, and the heat insulating layer 11C can be arbitrarily set.

The lower vertical pipe (pipe member) 120 includes an outer wall portion 12A forming an outer peripheral surface, an inner wall portion 12B forming an inner peripheral surface, and a heat insulating layer 12C formed between the outer wall portion 11A and the inner wall portion 12B. there is In addition, the lower vertical pipe (piping member) 120 has its pipe end inserted into the socket portion 13H on the lower side (second pipe end) of the expansion joint 10, and the pipe end is positioned at a predetermined position in the joint 10. The pipe end abuts against and is fixed.
The materials of the outer wall portion 12A, the inner wall portion 12B, and the heat insulating layer 12C are the same as those of the upper vertical pipe (pipe member) 110, and thus the description thereof is omitted.

As shown in FIG. 1, the seal member 20 has a projecting portion projecting toward the tube axis O and a skirt portion extending downward along the tube axis O from the outer edge of the projecting portion. The expansion joint 10 is mounted on the upper part of the expansion joint 10 , provided with a seal main body holding portion 21 having an inverted L-shaped cross section and a seal main body 22 attached inside the seal main body holding portion 21 .

A lip portion formed from the distal end side of the seal body 22 to the side of the pipe axis O and formed to be elastically deformable in the direction of the pipe axis O comes into sliding contact with the outer peripheral surface of the upper vertical pipe (pipe member) 110 . there is

The expansion joint 10 includes, for example, a body portion 11, a seal attachment portion 12, a lower pipe end portion 13, and a connection portion 14, as shown in FIGS. A seal member 20 is attached to the seal attachment portion 12 .

The trunk portion 11 is, for example, arranged on the upper side (first pipe end portion) of the expansion joint 10 and has a cylindrical shape formed along the pipe axis O, and a socket portion 11H is formed inside. .
In addition, a plurality of mounting ribs 16 for attaching mounting fittings for mounting the expansion joint 10 to a building are formed on the body portion 11 at intervals in the pipe axis O direction in the circumferential direction.

Further, as shown in FIGS. 1 and 3, the body portion 11 is arranged in the thickness direction, for example, and includes a non-foamed resin layer 111 forming a wall portion, a non-foamed resin layer 112 forming an inner wall portion, and a non-foaming resin layer 112 forming an inner wall portion. A foamed resin layer 113 is formed between the resin layer 111 and the non-foamed resin layer 112 and constitutes a heat insulating layer.
Moreover, it is preferable that the trunk portion 11 is formed to have a thickness of 6.5 mm or more and 13 mm or less.

The connecting portion 14 connects the trunk portion 11 and the lower pipe end portion 13 and has a diameter gradually reduced from the trunk portion 11 toward the lower pipe end portion 13 .
Moreover, the connecting portion 14 includes a non-foamed resin layer 111, a non-foamed resin layer 112, and a foamed resin layer 113, which are connected from the body portion 11. As shown in FIG.

As shown in FIG. 1, the foamed resin layer 113 includes, for example, a foamed resin layer upper end portion P1 positioned on the upper side (first pipe end portion side) and a foamed resin layer upper end portion P1 positioned on the lower side (second pipe end portion side). It is formed between the resin layer lower ends P2.
In addition, the foamed resin layer 113 has a total length L0 in the interaxial O direction. The total length L0 is set above the upper limit LA and below the lower limit LB at which the upper vertical pipe (pipe member) 110 moves in the pipe axis O direction.

Further, the foamed resin layer 113 is formed over the entire circumference of the trunk portion 11 and the connection portion 14 between the foamed resin layer upper end portion P1 and the foamed resin layer lower end portion P2.
Moreover, it is preferable that the thickness of the foamed resin layer 113 is set to 50% or more and 85% or less of the thickness of the body portion 11 .

In addition, on the outer peripheral surfaces of the body portion 11 and the connection portion 14, a burr 113V is formed between the foamed resin layer upper end portion P1 and the foamed resin layer lower end portion P2 (the range corresponding to the foamed resin layer in the direction of the pipe axis O). ing.

Also, at the portion of the burr 113V positioned on the outer peripheral portion of the mounting rib 16, when the resin reservoir (not shown) is removed, the burr removal mark 113A formed on the end face (removed surface) of the burr 113V is left on the tube. It is formed (exposed) along the axis O direction.
Here, it is preferable that the foamed resin is exposed in at least a part of the burr removal mark 113V.

The lower pipe end portion 13 is arranged on the lower side (second pipe end portion) of the expansion joint 10 and has a cylindrical shape formed along the pipe axis O, and a socket portion 13H is formed inside. there is
In this embodiment, the socket portion 13H is formed to have the same inner diameter as the socket portion 11H.

In addition, a stepped portion 15 is formed at the end portion of the lower pipe end portion 13 on the connection portion 14 side, and the pipe end of the lower vertical pipe (piping member) 120 abuts against the stepped portion 15 for sealing. A sealing member 17 is arranged for this purpose.

<Function of expansion joint>
Hereinafter, the operation of the expansion joint 10 in the expansion pipe structure 100 will be described with reference to FIGS. 4A and 4B. 4A and 4B are diagrams for explaining the outline of the action of the expansion/contraction pipe structure according to the first embodiment. FIG. 4A shows the state in which the upper vertical pipe is contracted, and FIG. 4B shows the state in which the upper vertical pipe is extended. It is a conceptual diagram showing. In the figure, the symbol LA indicates the upper limit of the pipe end 110T of the upper vertical pipe 110, and the symbol LB indicates the lower limit of the pipe end 110T.

First, the state in which the upper vertical pipe 110 is contracted will be described.
For example, when the outside air temperature drops, the upper vertical pipe 110 contracts and the pipe end 110T moves in the direction of the arrow T1.
The foamed resin layer upper end P1 is set, for example, such that the upper limit LA of the pipe end 110T when the upper vertical pipe 110 contracts is positioned below the foamed resin layer upper end P1.

Therefore, even if the upper vertical pipe 110 contracts and, for example, water flowing through the expansion joint structure 100 comes into direct contact with the inner surface of the expansion joint 10, the foamed resin layer 113 prevents heat from being conducted from the inner surface to the outer surface of the expansion joint 10. is suppressed. As a result, dew condensation on the expansion joint 10 can be suppressed.

Next, a state in which the upper vertical pipe 110 is extended will be described.
For example, when the outside air temperature rises, the upper vertical pipe 110 extends and the pipe end 110T moves in the direction of the arrow T2.
The foamed resin layer bottom end P2 is set, for example, so that the lower limit LB of the pipe end 110T when the upper vertical pipe 110 is extended is positioned above the foamed resin layer bottom end P2.

Therefore, even if the upper vertical pipe 110 is extended, the foamed resin layer 113 suppresses heat conduction from the inner surface to the outer surface of the expansion joint 10 . As a result, dew condensation on the expansion joint 10 can be suppressed.

<Method for manufacturing expansion joint>
Hereinafter, the outline of the method for manufacturing the expansion joint according to the first embodiment will be described with reference to FIGS. 5, 6A, and 6B. In this embodiment, the expansion joint is manufactured, for example, by injection molding.

In injection molding, for example, in a first injection step, a first resin that is a heat-melted non-foamable resin composition is injected into an injection mold, and then in a second injection step, the heat-melted foamable resin is injected. A first resin forming a composition is injected into an injection mold and removed from the injection mold after cooling.

In injection molding, the temperature (molding temperature) of the foamable resin composition immediately before injection into the injection mold is preferably 200° C. or higher and 280° C. or lower, more preferably 220° C. or higher and 260° C. or lower. When the molding temperature is within the above range, thermal decomposition of the thermoplastic resin is suppressed to prevent deterioration of transparency, and the resin is sufficiently melted to obtain good fluidity of the foamable resin composition.
The time for molding with a mold is preferably 1 minute or more and 10 minutes or less. If it is at least the lower limit value, it can be sufficiently cured, and if it is at most the above upper limit value, it is easy to improve the productivity of the foamed resin molded product.

In the first injection process and the second injection process, heating may be performed after injection. In the first injection step and the second injection step, the heating time and heating temperature can be appropriately set. Also, the cooling time and cooling rate can be appropriately set.

A schematic configuration of an injection mold for manufacturing the expansion joint according to the first embodiment will be described below with reference to FIG. FIG. 5 is a vertical cross-sectional view illustrating a schematic configuration of an injection mold. 5 is a vertical cross section corresponding to the cross section indicated by arrows III--III in FIG. In FIG. 5, reference numeral 200 denotes an injection mold, reference numeral C200 denotes a cavity, reference numeral C201 denotes a resin reservoir portion, reference numeral C202 denotes a resin escape groove, reference numeral 210 denotes an insert core (core), and reference numeral 220 The outer mold is shown.

The injection mold 200 includes, for example, an insert core (core) 210 and an outer mold 220, as shown in FIG. A cavity C200 corresponding to the expansion joint is formed between the insert core (core) 210 and the outer mold 220 .

The insert core (core) 210 includes, for example, a first insert core (core) 210A that corresponds to the socket portion 11H and is configured to move forward and backward along the axis O1, and a first insert core (core) 210A that corresponds to the socket portion 13H and is aligned with the axis O1. and a second insert core (core) 210B which is configured to be able to advance and retreat along. The first insert core 210A and the second insert core 210B are in contact with each other at their distal ends in the clamped state, and their base ends cooperate with the outer mold 220 to open the cavity C200 to the outside. to seal.

The outer mold 220 is, for example, a pair of mold members 220A that can be divided into left and right (front side and far side in FIG. 5) with the cross section shown in FIG. and a mold member 220B.

Further, the outer mold 220 is formed with, for example, an injection nozzle 200J, a resin reservoir C201, and a resin release groove C202 connecting the cavity C200 and the resin reservoir C201 on the mold mating surface.
It is preferable that the resin escape groove C202 is formed thinner (smaller interval) than the resin reservoir 202 and is formed to the outer peripheral side of the mounting rib 16, for example.

With such a configuration, the thin burr 113V formed by the resin release groove C202 can be easily broken after injection molding, and the foamed resin layer can be formed on the entire periphery of the body portion 11 and the connection portion 14 without complicated processing. 113 can be formed.

The resin reservoir C201 is formed on the side opposite to the injection nozzle 200J, and is arranged so that the second resin for forming the foamed resin layer is stably filled in the entire circumference of the body 11 of the expansion joint 10 in the circumferential direction. is configured to
The resin reservoir C201 and the resin escape groove C202 may be formed only on one side of the pair of mold members 220A and 220B.

Next, with reference to FIGS. 6A and 6B, an outline of a method for manufacturing an expansion joint will be described.
6A and 6B are diagrams for explaining the outline of the expansion joint manufacturing method. FIG. 6A is the first injection step, and FIG. 6B is the trunk portion of the expansion joint seen along the pipe axis direction in the second injection step. It is a conceptual diagram showing a cross section of.

(1) First Injection Step First, an injection nozzle (not shown) is attached to the molding die 200 . Then, a first resin J1 that forms a non-foamed resin layer is injected into the cavity C200.
The first resin J1 injected into the cavity C200 fills the cavity C200 halfway, for example, as shown in FIG. 6A. The filling amount of the first resin J1 can be set as appropriate.

[Non-foaming resin composition]
In this embodiment, the non-foaming resin composition forming the non-foaming resin layer contains, for example, one or more first resins selected from ABS resins and AES resins.

In the first resin J1, the content of units derived from a vinyl cyanide monomer is preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 45% by mass or less, relative to the total mass of the first resin J1. preferable. Tensile strength can be improved as content of the unit derived from a vinyl cyanide monomer is more than the said lower limit. Impact strength can be improved as content of the unit derived from a vinyl cyanide monomer is below the said upper limit.

The content of the rubber component in the first resin J1 is 1% by mass or more and 15% by mass or less, preferably 3% by mass or more and 13% by mass or less, and 5% by mass or more and 12% by mass or less, based on the total mass of the first resin J1. % by mass or less is more preferable, and 5% by mass or more and 10% by mass or less is even more preferable. When the content of the rubber component is at least the above lower limit, the strength can be easily increased. When the content of the rubber component is equal to or less than the above upper limit, the chemical resistance can be more easily improved.

In the first resin J1, the content of units derived from aromatic vinyl monomers is preferably 15% by mass or more and 60% by mass or less, more preferably 20% by mass or more and 50% by mass or less, relative to the total mass of the first resin J1. preferable. When the content of the unit derived from the aromatic vinyl monomer is at least the above lower limit, the indentation hardness can be improved. Impact strength can be improved as content of the unit derived from an aromatic vinyl monomer is below the said upper limit.

The content of each component in the first resin J1 is determined by analysis using pyrolysis gas chromatography/mass spectrometry (PGC/MS).
An example of measurement conditions using PGC/MS is shown below.
[Measurement condition]
・Equipment Pyrolyzer: PY-2020iD (Frontier Lab).
Gas chromatograph: GC 2010 (Shimadzu Corporation).
Mass spectrometer: GCMS-QP 2010 (Shimadzu Corporation).
- Thermal decomposition conditions Thermal decomposition temperature: 550°C.
Interface temperature: 250°C.
• Gas chromatograph conditions.
Carrier flow rate: 1 ml/min (He).
Split ratio: 100:1.
Separation column: DB-1 (1.00 μm, 0.25 mmφ×30 m).
Oven temperature: 40°C (3 min)-320°C (10 min).
- Mass spectrometry conditions Interface temperature: 250°C.
Ionization temperature: 220°C.
Mass range: 28-700 m/z.
Voltage: 1.2 kV.

A method for calculating the content of each component in the first resin J1 by PGC/MS measurement will be described.
First, each component constituting the first resin J1 is thermally decomposed and separated by pyrolysis gas chromatography to obtain a thermal decomposition pattern (pyrogram) in which each component is recorded as a peak. Next, for each peak of the thermal decomposition pattern, each component of acrylonitrile, rubber component, and styrene is specified by mass spectrum obtained by a mass spectrometer.
Here, acrylonitrile, rubber component, and styrene each have a different depolymerization rate (the rate at which the polymer decomposes into monomers) due to thermal decomposition, so the peak area (X) of each component is The peak area (Z) of each component is obtained by dividing by the depolymerization rate (Y) of the component. The depolymerization rate (Y) of each component is acrylonitrile: 0.15, rubber component: 0.10, and styrene: 1.0.
Then, the ratio (Z/T) to the total sum (T) of the peak areas (Z) of each component in the thermal decomposition pattern is defined as the content of each component in the first resin J1.

In the non-foaming resin composition, the content of the first resin J1 with respect to the total mass of the non-foaming resin composition is preferably 45% by mass or more and 90% by mass or less, more preferably 50% by mass or more and 85% by mass or less.

The non-foamable resin composition of the present embodiment may contain other resins than the first resin J1.
Examples of other resins include polyvinyl resins, polyester resins, polyether resins, polyacrylic resins, polyimide resins, and the like. These may be used alone, or two or more of them may be used in combination.

The non-foamable resin composition of the present embodiment preferably further contains a polyacrylic resin. Examples of polyacrylic resins include acrylic acid ester polymers and methacrylic acid ester polymers. Polymers of acrylic acid esters include polymethyl acrylate, polyethyl acrylate, and polyglycidyl acrylate. Polymers of methacrylic acid esters include polymethyl methacrylate, polyethyl methacrylate, and polyglycidyl methacrylate.
The content of the polyacrylic resin is preferably 20% by mass or more and 60% by mass or less, more preferably 30% by mass or more and 50% by mass or less, relative to the total mass of the resin in the non-foamable resin composition. When the content of the polyacrylic resin is within the above numerical range, it is easy to increase the strength and transparency of the foamed resin molded product.
The content of the polyacrylic resin is preferably 10% by mass or more and 55% by mass or less, more preferably 20% by mass or more and 50% by mass or less, relative to the total mass of the non-foamable resin composition.

The content of each component in the non-foamable resin composition containing the first resin J1 and other resins is determined by analysis using pyrolysis gas chromatography/mass spectrometry (PGC/MS). Measurement conditions are the same as those for the first resin. The content of each component in the first resin J1 can be calculated by the same calculation method as the content of each component in the first resin.
The depolymerization rates of acrylonitrile, rubber component, styrene, and polyacrylic resin are acrylonitrile: 0.15, rubber component: 0.10, styrene: 1.0, and polyacrylic resin: 1.0.

In the non-foaming resin composition, the content of the first resin J1 is preferably 40% by mass or more and 100% by mass or less, more preferably 45% by mass or more and 100% by mass, relative to the total mass of the resins in the non-foaming resin composition. % or less, and more preferably 50% by mass or more and 100% by mass or less.

The non-foamable resin composition of the present embodiment may contain components (optional components) other than the first resin J1 within a range that does not impair the effects of the present invention.

The content of the optional component is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less with respect to 100 parts by mass of the first resin J1.

The non-foamable resin composition of the present embodiment can contain the first resin J1 and optional components. The non-foamable resin composition may be a mixture in which all components are premixed, or may be in the form of mixing all or part of all components in a molding machine. The pre-mixed mixture of all components may be powdered or pelletized.
The non-foaming resin composition of the present embodiment forms a non-foaming resin layer covering the outer surface of the foamed resin molded article of the present invention. In addition, in the non-foamable resin composition of the present embodiment, the content of the rubber component in the first resin J1 is 1% by mass or more and 15% by mass or less with respect to the total mass of the first resin J1. Therefore, the non-foamed resin layer has excellent chemical resistance, and the foamed resin molded article of the present invention has excellent chemical resistance.

(2) Second Injection Step Next, an injection nozzle (not shown) is attached to the molding die 200 to inject a second resin J2 that forms a foamed resin layer into the cavity C200.
As shown in FIG. 6B, the injected second resin J2 advances through the first resin J1 while pushing away the first resin J1 filled in the first injection step, and fills the first resin J1. At the same time, the first resin J1 is moved toward the resin reservoir C201 within the cavity C200. At this time, the insert core 210 and the first resin J1 cooled by the outer mold 220 form the non-foamed resin layers 111 and 112 . Then, the second resin J2 joins on the resin escape groove C202 side by pushing the first resin J1 into the resin reservoir portion C201 through the resin escape groove C202.
In the second injection step, only the first resin J1 may move to the resin reservoir C201, or both the first resin J1 and the second resin J2 may fill the resin reservoir C201.
As a result, the second resin J2 is stably filled between the non-foamed resin layer 111 and the non-foamed resin layer 112, and the foamed resin layer 113 is formed over the entire circumference of the trunk portion 11 and the connecting portion 14 of the expansion joint main body. be done.
When molding and cooling of the injection-molded product (intermediate product) of the expansion joint 10 in the second injection molding process are completed, the injection-molded product with the burr and the resin reservoir is removed from the injection mold 200 .

[Expandable resin composition]
In this embodiment, the foamable resin composition forming the foamed resin layer comprises at least one second resin J2 selected from acrylonitrile-butadiene-styrene copolymers and acrylonitrile-ethylenepropylenediene-styrene copolymers. and a blowing agent.

The second resin J2 is one selected from acrylonitrile-butadiene-styrene copolymer (hereinafter also referred to as ABS resin) and acrylonitrile-ethylene propylene diene-styrene copolymer (hereinafter also referred to as AES resin). That's it.
Acrylonitrile-butadiene-styrene copolymers and acrylonitrile-ethylene propylene diene-styrene copolymers are resins obtained by polymerizing aromatic vinyl monomers and vinyl cyanide monomers in the presence of rubber components.
In the present specification, the rubber component refers to a monomer component that is a raw material for diene rubber such as polybutadiene and polyisoprene.
Examples of rubber components include butadiene, isoprene, ethylene, and propylene.
Examples of aromatic vinyl monomers include styrene and α-methylstyrene.
Vinyl cyanide monomers include acrylonitrile, methacrylonitrile, and the like.

In the second resin J2, the content of units derived from a vinyl cyanide monomer is preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 45% by mass or less, relative to the total mass of the second resin J2. preferable. Tensile strength can be improved as content of the unit derived from a vinyl cyanide monomer is more than the said lower limit. Impact strength can be improved as content of the unit derived from a vinyl cyanide monomer is below the said upper limit.

The content of the rubber component in the second resin J2 is not particularly limited, and is preferably 1% by mass or more and 20% by mass or less with respect to the total mass of the second resin J2.

In the second resin J2, the content of units derived from aromatic vinyl monomers is preferably 15% by mass or more and 60% by mass or less, more preferably 20% by mass or more and 50% by mass or less, relative to the total mass of the second resin J2. preferable. When the content of the unit derived from the aromatic vinyl monomer is at least the above lower limit, the indentation hardness can be improved. Impact strength can be improved as content of the unit derived from an aromatic vinyl monomer is below the said upper limit.

The content of each component in the second resin J2 is determined by analysis using pyrolysis gas chromatography/mass spectrometry (PGC/MS). Measurement conditions are the same as those for the first resin J1.

In the foamable resin composition, the content of the second resin J2 is preferably 45% by mass or more and 90% by mass or less, more preferably 50% by mass or more and 85% by mass or less, relative to the total mass of the foamable resin composition.

The foamable resin composition of the present embodiment may contain other resins than the second resin J2.
Examples of other resins include polyacrylic resins such as polymethyl acrylate, polyethyl acrylate, polyglycidyl acrylate, polymethyl methacrylate, polyethyl methacrylate, and polyglycidyl methacrylate, polyvinyl resins, polyester resins, poly Ether resins, polyimide resins and the like can be mentioned. These may be used alone, or two or more of them may be used in combination.

In the foamable resin composition, the content of the second resin J2 is preferably 70% by mass or more and 100% by mass or less, and 85% by mass or more and 100% by mass or less, relative to the total mass of the resins in the foamable resin composition. is more preferred.

[Blowing agent]
As the foaming agent, either a volatile foaming agent or a decomposable foaming agent may be used.
Volatile foaming agents include, for example, aliphatic hydrocarbons, alicyclic hydrocarbons, halogenated hydrocarbons, ethers, ketones and the like. Of these, aliphatic hydrocarbons include propane, butane (normal butane, isobutane), pentane (normal pentane, isopentane, etc.), and alicyclic hydrocarbons include cyclopentane, cyclohexane, and the like. mentioned. Examples of halogenated hydrocarbons include one or more of halogenated hydrocarbons such as trichlorofluoromethane, trichlorotrifluoroethane, tetrafluoroethane, chlorodifluoroethane, and difluoroethane. Examples of ethers include dimethyl ether and diethyl ether, and examples of ketones include acetone and methyl ethyl ketone.

Examples of decomposition type foaming agents include inorganic foaming agents such as sodium bicarbonate (sodium hydrogen carbonate), sodium carbonate, ammonium bicarbonate, ammonium nitrite, azide compounds, sodium borohydride, azodicarbonamide, barium azodicarboxylate, Organic foaming agents such as dinitrosopentamethylenetetramine are included.
In addition, gases such as carbon dioxide, nitrogen, and air may be used as foaming agents.
From the viewpoint of excellent foaming performance, a decomposable foaming agent is preferred, and sodium bicarbonate and azodicarbonamide are more preferred.
These may be used alone, or two or more of them may be used in combination.
The content of the foaming agent is preferably 0.1 parts by mass or more and 8 parts by mass or less, more preferably 1 part by mass or more and 5 parts by mass or less, and 1 part by mass or more and 3 parts by mass with respect to 100 parts by mass of the second resin J2. Part or less is more preferable.

The foamable resin composition of the present invention may contain components (optional components) other than the second resin J2 and the foaming agent within a range that does not impair the effects of the present invention.

The content of the optional component is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less with respect to 100 parts by mass of the second resin J2.

The foamable resin composition of the present invention can contain a second resin J2, a foaming agent, and optional components. The foamable resin composition may be a mixture in which all components are premixed, or may be in the form of mixing all or part of all components in a molding machine. The pre-mixed mixture of all components may be powdered or pelletized.

Next, the injection-molded product taken out from the injection mold is transferred to, for example, a trimming press process or a cutting process to remove burrs and resin pools.
As a result, burr removal traces are formed on the end face of the burr. In addition, for example, in a grinding process or the like, the burr-removed marks may be surface-treated.

According to the expansion joint 10 and the expansion pipe structure 100 according to the first embodiment, since the foamed resin layer 113 is formed over the entire circumference of the trunk portion 11 and the connection portion 14 of the joint body, the upper heat insulation pipe ( Even if the piping member 110 shrinks and the low-temperature water comes into direct contact with the inner surface of the expansion joint 10, cooling of the outer surface of the expansion joint 10 is suppressed.
As a result, condensation on the outer surface of the expansion joint 10 can be suppressed.

Further, according to the expansion joint 10 according to the first embodiment, the foamed resin layer 113 is formed over the entire length (<L) of movement of the pipe end 110T of the upper heat insulating pipe 110 along the direction of the pipe axis O. , dew condensation on the outside of the expansion joint 10 is suppressed even if the upper heat insulating pipe 110 expands and contracts.

Further, according to the expansion joint 10 according to the first embodiment, the burr removal mark 113A is formed over the entire length L0 of the range (P1 to P2) in which the foamed resin layer 113 is embedded in the pipe axis O direction. The foamed resin layer 113 can be stably embedded over the entire circumference of the inside of the trunk portion 11 over the entire length L of the target range in the direction.
Moreover, it is possible to efficiently inspect whether or not the foamed resin layer is formed over the entire length of the target range.
In addition, by easily confirming the range in which the foamed resin layer is formed at the time of piping construction, construction can be efficiently performed.

According to the expansion joint 10 according to the first embodiment, the thickness of the trunk portion 11 is formed to be 6.5 mm or more and 13 mm or less, and the thickness of the foamed resin layer 113 is 50% or more and 85% of the thickness of the trunk portion 11. Since it is formed below, the heat insulation effect can be efficiently ensured.

<Second embodiment>
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 7 is a perspective view explaining a schematic configuration of an expansion joint according to a second embodiment of the present invention. In FIG. 7, reference numeral 10A indicates an expansion joint, and reference numeral 113B indicates burr removal marks.

The expansion joint 10A includes a body portion 11, a seal attachment portion 12, a lower pipe end portion 13, and a connection portion 14, as shown in FIG. A connection portion 14 is formed in the lower portion of the body portion 11 so that the diameter of the connection portion 14 is reduced toward the lower pipe end portion 13 .

In addition, a plurality of mounting ribs 16 formed over the entire circumference of the body portion 11 are arranged at intervals in the direction of the pipe axis O. As shown in FIG.
Further, in the body portion 11, in the direction of the pipe axis O, burr removal traces 113A are formed over the entire length of the range in which the foamed resin layer (not shown) is embedded.
The expansion joint 10A according to the third embodiment is different from the expansion joint 10 according to the first embodiment in that the burr 113V formed by the resin escape groove is removed along the outer diameter of the mounting rib 16, and the burr removal mark is removed. 113A is formed according to the unevenness of the mounting rib 16, and the rest is the same as in the first embodiment, so the same reference numerals are given and the description is omitted.

<Third Embodiment>
A third embodiment of the present invention will now be described with reference to FIG.
FIG. 8 is a perspective view illustrating a schematic configuration of an expansion joint according to a third embodiment of the invention. In FIG. 8, reference numeral 10B indicates an expansion joint, and reference numeral 113C indicates burr removal marks.

The expansion joint 10B includes a body portion 11, a seal attachment portion 12, a lower pipe end portion 13, and a connection portion 14, as shown in FIG.

Further, in the body portion 11, in the direction of the pipe axis O, burr removal traces 113C are formed over the entire length of the range in which the foamed resin layer (not shown) is embedded.
The expansion joint 10B according to the third embodiment differs from the expansion joint 10 according to the first embodiment in that no mounting rib is formed on the body portion 11, and the rest is the same as the first embodiment. Therefore, the same reference numerals are given and the description thereof is omitted.

It should be noted that the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention.

For example, in the above embodiment, the case where the foamed resin layer 113 is formed over the entire length of the trunk portion 11 and the connection portion 14 of the expansion joint 10 has been described. It may be formed in a partial range of the portion 11 .

Further, in the above embodiment, the expansion joint 10 is applied to the expansion pipe structure 100 for discharging the drain of the air conditioner, but it may be applied for the purpose of discharging the drain of the air conditioner.

Further, in the above-described embodiment, the case where the burr and the burr-removed trace are formed over the entire length of the foamed resin layer 113 has been described, but whether or not the burr is formed in the portion corresponding to the foamed resin layer of the joint body may be determined as appropriate. In the case of forming burrs, it is possible to appropriately set in which range in the direction of the tube axis O the burrs and the burr-removed traces are set.

Further, in the above embodiment, the resin constituting the outer and inner walls of the upper heat insulating pipe 110 and the lower heat insulating pipe 120 is, for example, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer (ABS resin), polyethylene. , the non-foaming resin of polypropylene has been described, but the resin constituting the outer and inner walls of the upper heat insulating pipe 110 and the lower heat insulating pipe 120 can be set as appropriate.

Further, in the above embodiment, the resin constituting the heat insulating layer of the upper heat insulating pipe 110 and the lower heat insulating pipe 120 is, for example, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer (ABS resin), polyethylene, or polypropylene. Although the case of using foamed resin has been described, the resin constituting the heat insulating layer of the upper heat insulating pipe 110 and the lower heat insulating pipe 120 can be set as appropriate.

Further, in the above embodiment, the resin constituting the non-foamed resin layers 111 and 112 in the expansion joint 10 contains, for example, one or more first resins selected from ABS resin and AES resin. Although the case has been described, the resin forming the expansion joint 10 can be appropriately set.

Further, in the above embodiment, the resin constituting the foamed resin layer 113 in the expansion joint 10 is, for example, one selected from acrylonitrile-butadiene-styrene copolymer and acrylonitrile-ethylene propylene diene-styrene copolymer. Although the case where the second resin J2 and the foaming agent are included has been described above, the resin forming the foamed resin layer 113 can be set as appropriate.
Moreover, the resins forming the foamed resin layer 113 and the non-foamed resin layers 111 and 112 may be made of different materials.

In the above-described embodiment, the expansion joint 10 is formed such that the thickness of the trunk portion 11 is 6.5 mm or more and 13 mm or less, and the thickness of the foamed resin layer 113 is 50% or more and 85% of the thickness of the trunk portion 11. Although the case where they are formed has been described below, the thickness of the body portion 11 and the thickness of the foamed resin layer 113 can be appropriately set.

In the above embodiment, the case where the lower pipe end (second pipe end) of the expansion joint 10 is the receptacle portion 13H has been described. ) may be the insert.

In addition, it is possible to appropriately replace the constituent elements in the above-described embodiments with well-known constituent elements without departing from the scope of the present invention, and the above-described embodiments may be appropriately combined and applied.

P1 Upper end of foamed resin layer P2 Lower end of foamed resin layer 10, 10A, 10B Expansion joint 11 Body 11H Socket 12 Seal mounting part 13 Lower pipe end (second pipe end)
13H socket part 14 connection part 15 stepped part 16 mounting rib 17 sealing member 110 upper heat insulating pipe (piping member)
120 lower heat insulation piping (piping member)
100 Expandable pipe structures 111, 112 Non-foamed resin layer 113 Foamed resin layers 113A, 113B, 113C Burr removal mark C201 Resin reservoir

Claims (4)

a joint body having a barrel formed in a cylindrical shape;
a receptacle formed at the first end of the joint body;
with
An expansion joint in which a pipe end of a piping member is inserted into the socket, and the pipe end can expand and contract along the pipe axis direction of the joint body,
Inside the trunk,
Equipped with a foamed resin layer in which foamed resin is embedded over the entire circumference ,
An expansion joint characterized in that burr removal traces are formed over the entire length of the range in which the foamed resin layer is embedded in the pipe axis direction of the joint body. An expansion joint according to claim 1,
The foamed resin layer is
An expansion joint characterized in that the expansion joint is formed over the entire length of the joint body in the pipe axial direction in which the pipe end of the pipe member moves as the pipe member inserted into the socket expands and contracts. The expansion joint according to claim 1 or 2 ,
The trunk portion of the joint body has a thickness of 6.5 mm or more and 13 mm or less,
The thickness of the foamed resin layer is
An expansion joint characterized in that the thickness of the trunk portion is 50% or more and 85% or less. The expansion joint according to any one of claims 1 to 3 ;
a piping member;
with
An expandable pipe structure, wherein a pipe end of the pipe member is inserted into the socket, and the pipe end is expandable along the pipe axis direction of the joint body.

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