Multi-layer fittings and piping systems

Abstract

To provide a multilayer joint which can further enhance cutoff performance, and a piping system.SOLUTION: A multilayer joint 1 has a tubular joint main body 10 having a flow passage 15 therein, and also having opening parts at both ends; a first receptacle part 12A surrounding an opening part 10A of the joint main body 10 at one end; a second receptacle part 12B surrounding an opening part 10B of the joint main body 10 at the other end, the first receptacle part 12A and the second receptacle part 12B are plane-symmetric with respect to a virtual plane P1, the first receptacle 12 has a first receptacle member 20A which is integrally formed at an inner face, the second receptacle part 12B has a second receptacle member 20B which is integrally formed at an inner face, the joint main body 10 has a gate mark G at an outer face, and the gate mark G is located above the virtual plane P1, and above the pipe axis O of the joint main body 10 in a back face view.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a multi-layer joint and piping system. [Background technology]

[0002] Conventionally, single-layer resin joints formed by injection molding a single resin have been used for connecting resin pipes, etc. As a resin joint, a multi-layer joint having an inner layer and an outer layer using different types of resin materials for the purpose of imparting various functions is known. For example, Patent Document 1 proposes a multi-layer joint in which an inner layer is made of a resin material capable of adhesively bonding to a resin pipe member, and an outer layer is made of a resin material capable of absorbing the thermal expansion and contraction stress of the resin pipe member. The multi-layer joint of Patent Document 1 aims to improve fatigue fracture resistance strength due to thermal expansion and contraction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-002012 A Summary of the Invention [Problem to be solved by the invention]

[0004] The multi-layer joint of Patent Document 1 exhibits watertight performance by thermal contraction between the resin of the inner layer of the receiving portion and the resin of the outer layer of the receiving portion. However, there is a demand for multi-layer joints with improved water-stopping properties.

[0005] The present invention has been made in consideration of such problems, and has as its object to provide a multi-layer joint and a piping system that can further improve water-stopping properties. [Means for solving the problem]

[0006] As a result of extensive research, the inventors discovered that if the water-stopping performance differs from one receiving part to another, water leakage will occur from the receiving part with poor water-stopping performance, and have completed the present invention. That is, the present invention has the following aspects. [1] A multi-layer joint comprising: a tubular joint body having a flow path therein and openings on both ends; a first receiving portion surrounding the opening at one end of the joint body; and a second receiving portion surrounding the opening at the other end of the joint body, wherein the first receiving portion and the second receiving portion are symmetrical with respect to an imaginary plane, a first annular step portion protruding toward the flow path is formed at a boundary between the joint body and the first receiving portion, and a second annular step portion protruding toward the flow path is formed at a boundary between the joint body and the second receiving portion, the first receiving portion has a first receiving member formed integrally with an inner surface, and the second receiving portion has a second receiving member formed integrally with an inner surface, the joint body has a gate mark on its outer surface, and the gate mark is located on the imaginary plane and on the pipe axis of the joint body when viewed from behind. [2] The multilayer joint described in [1], wherein the first receiving member is formed of a resin containing one or more selected from rigid polyvinyl chloride resin, ABS (acrylonitrile-butadiene-styrene copolymer) resin, acrylic resin, polycarbonate resin, polyethylene terephthalate resin, and urethane resin, and the second receiving member is formed of a resin containing one or more selected from rigid polyvinyl chloride resin, ABS (acrylonitrile-butadiene-styrene copolymer) resin, acrylic resin, polycarbonate resin, polyethylene terephthalate resin, and urethane resin. [3] The multilayer joint according to [1] or [2], wherein the joint body is formed of a resin containing one or more selected from a fluorine-based resin, a polyphenylsulfone-based resin, a polyphenylene sulfide-based resin, and an olefin-based resin.

[0007] [4] A piping system comprising the multilayer joint according to any one of [1] to [3], a first pipe disposed inside the first receiving member, and a second pipe disposed inside the second receiving member, wherein the first pipe and the second pipe have at least a pipe inner layer facing the flow path and a pipe outer layer located on the outer surface, the pipe inner layer is formed of a resin containing one or more selected from a fluorine-based resin, a polyphenylsulfone-based resin, a polyphenylene sulfide-based resin, and an olefin-based resin, the pipe outer layer contains a vinyl chloride-based resin, an end face of the first pipe abuts the first step, and the pipe outer layer of the first pipe abuts the inner surface of the first receiving member, an end face of the second pipe abuts the second step, and the pipe outer layer of the second pipe abuts the inner surface of the second receiving member. Effect of the Invention

[0008] According to the multi-layer joint of the present invention, the water-stopping property can be further improved. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a side cross-sectional view of a multi-layer joint according to one embodiment of the present invention. [Diagram 2] 2 is a rear view of the multi-layer joint as seen from the arrow X in FIG. 1. [Diagram 3] FIG. 11 is a side view of a multi-layer joint according to another embodiment of the present invention. [Figure 4] FIG. 2 is a perspective view of a receiving member according to an embodiment of the present invention. [Diagram 5] FIG. 1 is a partial cross-sectional view of a piping system according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, one embodiment of a multi-layer joint according to the present invention will be described with reference to FIG. As shown in FIG. 1, the multilayer joint 1 of this embodiment is a joint for a curved pipe called an elbow. The multilayer joint 1 is tubular and has openings at both ends. The multilayer joint 1 has a tubular joint body 10 having a flow path 15 inside and openings at both ends, a first socket portion 12A surrounding the opening 10A at one end of the joint body 10, and a second socket portion 12B surrounding the opening 10B at the other end of the joint body 10. A first socket member 20A is integrally formed with the first socket portion 12A. A second socket member 20B is integrally formed with the second socket portion 12B.

[0011] The first socket portion 12A and the second socket portion 12B are symmetrical with respect to an imaginary plane P1. That is, the imaginary plane P1 is a symmetrical plane between the first socket portion 12A and the second socket portion 12B. The imaginary plane P1 can be defined as a plane that connects corresponding positions of the first receiving portion 12A and the second receiving portion 12B (e.g., the opening end of the receiving portion, the base end of the receiving portion, the center of the opening of the receiving portion, etc.) with straight lines and passes through all of the midpoints of these straight lines. In this specification, "plane symmetric" means that the distance from an imaginary plane to the corresponding positions of the two sockets is allowed to vary by up to ±10%.

[0012] The body resin forming the joint body 10 forms the socket outer layer 51 of the first socket portion 12A and the second socket portion 12B. The first socket member 20A forms the socket inner layer 52 of the first socket portion 12A. The second socket member 20B forms the socket inner layer 52 of the second socket portion 12B. The multilayer joint 1 is, for example, an insert molded product, and the joint body 10 is formed of a single resin (main body resin). In the first receiving portion 12A, the layer formed by the first receiving member 20A is the receiving port inner layer 52, and the layer formed by the main body resin is the receiving port outer layer 51. In the second receiving portion 12B, the layer formed by the second receiving member 20B is the receiving port inner layer 52, and the layer formed by the main body resin is the receiving port outer layer 51.

[0013] When viewed from open end 14A of first socket 12A, multilayer joint 1 has an annular first step 13A that protrudes toward flow path 15 at the boundary between joint body 10 and first socket 12A. When viewed from open end 14B of second socket 12B, multilayer joint 1 has an annular second step 13B that protrudes toward flow path 15 at the boundary between joint body 10 and second socket 12B.

[0014] The joint body 10 has a pipe axis O along a curvature. The first socket portion 12A has a first tube axis O1. The first tube axis O1 extends from an open end 14A of the first socket portion 12A toward the first step portion 13A. The second socket portion 12B has a second tube axis O2. The second tube axis O2 extends from an open end 14B of the second socket portion 12B in a direction toward the second step portion 13B. The tube axis O is in contact with a first tube axis O1 at the boundary with the first socket portion 12A. The tube axis O is in contact with a second tube axis O2 at the boundary with the second socket portion 12B. The first tube axis O1 and the second tube axis O2 intersect at an angle θ. The angle θ is preferably 90±1.1°, and more preferably 90°.

[0015] The joint body 10 has a gate mark G on its outer surface, which is a mark of the resin injection portion. The gate mark G has a certain region (area). In this specification, the "gate mark G" refers to a portion of the outer surface of the joint body 10 that protrudes visually from the surrounding area. FIG. 2 shows the multi-layer joint 1 as viewed from the rear side (arrow X in FIG. 1) on the same plane as imaginary plane P1. 2, the gate mark G is on a virtual plane P1. In addition, the gate mark G is located on the pipe axis O of the joint body 10 in rear view. In this specification, "the gate mark G is located on the imaginary plane P1 and on the pipe axis O of the joint body 10 in rear view" means that "the gate mark G is formed so that its area includes the intersection Q between the imaginary plane P1 and the pipe axis O in rear view." In rear view, the center of the gate mark G and the intersection point Q do not have to coincide with each other, but it is preferable that the center of the gate mark G and the intersection point Q coincide with each other.

[0016] In the first receiving portion 12A, the distance in the first tube axis O1 direction from the gate mark G to the open end 14A is L1. The distance in the first tube axis O1 direction from the gate mark G to the first step portion 13A is Z1. In the second receiving portion 12B, the distance in the second tube axis O2 direction from the gate mark G to the opening end 14B is L2. The distance in the second tube axis O2 direction from the gate mark G to the second step portion 13B is Z2.

[0017] In the multilayer joint 1, the ratio of the distance Z2 to the distance Z1 (also referred to as the "ratio Z2 / Z1") is 0.90 to 1.10, preferably 0.95 to 1.05, more preferably 0.98 to 1.02, and most preferably 1.00. When the ratio Z2 / Z1 is within the above numerical range, the difference between the distance from the resin injection portion (gate) of the mold forming the multilayer joint 1 to the first receiving portion 12A and the distance from the gate to the second receiving portion 12B is small. Therefore, there is no difference in the cooling speed or flow time of the resin composition for each receiving portion, and the resin composition is thermally shrunk uniformly. As a result, the watertightness performance of each receiving portion becomes equal, and the watertightness of the multilayer joint 1 can be further improved.

[0018] The distance Z1 is appropriately determined according to the application of the multilayer joint 1, and is, for example, preferably 20 to 500 mm, more preferably 30 to 400 mm, and even more preferably 40 to 300 mm. When the distance Z1 is equal to or greater than the lower limit, the joint body 10 is easily molded. When the distance Z1 is equal to or less than the upper limit, the distance to the first step 13A is not too long, and a weld line is less likely to be formed. Note that the weld line is the part where the resin composition meets after it has cooled the most, and is weaker in strength than other regions. When a weld line is less likely to be formed, the intrusion of water flowing through the flow path 15 from the boundary between the receiving port inner layer 52 and the receiving port outer layer 51 can be suppressed. This further improves the water-stopping property of the multilayer joint 1. Distance Z2 is similar to distance Z1. The distances Z1 and Z2 can be measured using a caliper, a curved ruler, or the like.

[0019] In the multilayer joint 1, the ratio of the distance L2 to the distance L1 (also referred to as the "ratio L2 / L1") is 0.90 to 1.10, preferably 0.95 to 1.05, more preferably 0.98 to 1.02, and most preferably 1.00. When the ratio L2 / L1 is within the above numerical range, the difference between the distance from the gate of the mold forming the multilayer joint 1 to the opening end 14A of the first socket portion 12A and the distance from the gate to the opening end 14B of the second socket portion 12B is small. Therefore, there is no difference in the cooling speed or flow time of the resin composition for each socket portion, and the resin composition is thermally shrunk uniformly. As a result, the water-stopping performance of each socket portion becomes equal, and the water-stopping property of the multilayer joint 1 can be further improved.

[0020] The distance L1 is appropriately determined depending on the application of the multilayer joint 1, and is, for example, preferably 30 to 800 mm, more preferably 40 to 600 mm, and even more preferably 50 to 400 mm. When the distance L1 is equal to or greater than the above lower limit, the multilayer joint 1 is easily molded. When the distance L1 is equal to or less than the above upper limit, the distance to the opening end 14A does not become too long, and a weld line is unlikely to be formed. This allows the water-stopping property of the multilayer joint 1 to be further improved. Distance L2 is similar to distance L1. The distances L1 and L2 can be measured using a vernier caliper, a curved ruler, or the like.

[0021] Opening diameter R of first receiving portion 12A 12A is appropriately determined depending on the application of the multilayer joint 1, and is, for example, preferably 20 to 300 mm, more preferably 30 to 200 mm, and further preferably 40 to 100 mm. 12A When the opening diameter R is equal to or larger than the lower limit, it is easy to form the opening diameter R of the first receiving member 20A integrally. 12A When it is equal to or less than the above upper limit, the strength of the first receiving portion 12A can be further increased. Opening diameter R of second receiving portion 12B 12B is the opening diameter R of the first receiving portion 12A. 12A is the same as: Opening diameter R 12A , opening diameter R 12B can be measured using a vernier caliper, a curved ruler, etc.

[0022] Height H of the first step 13A 13A The height H is appropriately determined depending on the application of the multilayer joint 1, and is, for example, preferably 1 to 20 mm, more preferably 2 to 15 mm, and further preferably 3 to 10 mm. 13A If the height H is equal to or greater than the lower limit, the pipe can be easily fixed. 13A When it is equal to or less than the above upper limit, the strength of the first receiving portion 12A can be further increased. In addition, the height H 13A refers to the distance from the inner surface of the joint body 10 at the first step 13A to the inner surface of the first socket portion 12A at the first step 13A. Height H of the second step 13B 13B is the height H of the first step 13A 13A is the same as: Height H 13A , height H 13B can be measured using a vernier caliper, a curved ruler, etc.

[0023] Length L of the rear side of the joint body 10 10MAX The length L is appropriately determined depending on the application of the multilayer joint 1, and is, for example, preferably 50 to 1000 mm, more preferably 100 to 700 mm, and even more preferably 150 to 500 mm. 10MAX When the length L is equal to or greater than the lower limit, the multilayer joint 1 is easily formed. 10MAX When it is equal to or less than the above upper limit value, the strength of the multilayer joint 1 can be further increased. Length L 10MAX can be measured using a tape measure, a square, etc.

[0024] Length L of the front side of the joint body 10 10MIN The length L is appropriately determined depending on the application of the multilayer joint 1, and is, for example, preferably 10 to 300 mm, more preferably 15 to 200 mm, and even more preferably 20 to 150 mm. 10MIN When the length L is equal to or greater than the lower limit, the multilayer joint 1 is easily formed. 10MIN When it is equal to or less than the above upper limit value, the strength of the multilayer joint 1 can be further increased. Length L 10MIN can be measured using a tape measure, a square, etc.

[0025] Wall thickness T of fitting body 1010 The thickness T of the joint body 10 is appropriately determined depending on the application of the multilayer joint 1, and is preferably 1 to 30 mm, more preferably 2 to 20 mm, and further preferably 3 to 10 mm, for example. 10 When the thickness T of the joint body 10 is equal to or greater than the lower limit, the strength of the joint body 10 can be further increased. 10 When the ratio is equal to or less than the upper limit, the amount of the main body resin used can be reduced. In this specification, the term "wall thickness" refers to the thickness at the thinnest position of the member (minimum wall thickness). Wall thickness T of fitting body 10 10 can be obtained, for example, by cutting the joint body 10 on an imaginary plane P1 and measuring with a vernier caliper, a curved ruler, or the like.

[0026] The thickness T of the first receiving portion 12A 12A The thickness T is appropriately determined depending on the application of the multilayer joint 1, and is preferably 1 to 20 mm, more preferably 2 to 15 mm, and further preferably 3 to 10 mm. 12A When the thickness T is equal to or greater than the lower limit, the strength of the first receiving portion 12A can be further increased. 12A When the ratio is equal to or less than the upper limit, the amount of the main body resin used can be reduced. The thickness T of the second receiving portion 12B 12B is the thickness T of the first receiving portion 12A. 12A is the same as: Wall thickness T 12A , wall thickness T 12B can be measured using a vernier caliper, a curved ruler, etc.

[0027] In the multi-layer joint 1, the position of the gate mark G can be adjusted by the position of the gate provided in the mold when molding the multi-layer joint 1.

[0028] The multilayer joint 2 shown in FIG. 3 is a straight pipe joint called a socket. The multilayer joint 2 is cylindrical and has openings at both ends. The multilayer joint 2 has a tubular joint body 11 having a flow path 19 therein, a first socket portion 16A surrounding an opening 11A at one end of the joint body 11, and a second socket portion 16B surrounding an opening 11B at the other end of the joint body 11. A first socket member 20C is integrally formed with the first socket portion 16A. A second socket member 20D is integrally formed with the second socket portion 16B.

[0029] The first socket portion 16A and the second socket portion 16B are symmetrical with respect to an imaginary plane P2. That is, the imaginary plane P2 is a symmetrical plane between the first socket portion 16A and the second socket portion 16B.

[0030] The body resin forming the joint body 11 forms the socket outer layer 51 of the first socket portion 16A. The body resin forming the joint body 11 forms the socket outer layer 51 of the second socket portion 16B. The first socket member 20C forms the socket inner layer 52 of the first socket portion 16A. The second socket member 20D forms the socket inner layer 52 of the second socket portion 16B. The multilayer joint 2 is, for example, an insert molded product, and the joint body 11 is formed of a single resin (main body resin). In the first socket portion 16A, the layer formed by the first socket member 20C is the socket inner layer 52, and the layer formed by the main body resin is the socket outer layer 51. In the second socket portion 16B, the layer formed by the second socket member 20D is the socket inner layer 52, and the layer formed by the main body resin is the socket outer layer 51.

[0031] At the boundary between the joint body 11 and the first socket 16A of the multilayer joint 2, a first annular step 17A is formed which protrudes toward the flow path 19 when viewed from the open end 18A of the first socket 16A. At the boundary between the joint body 11 and the second socket 16B of the multilayer joint 2, a second annular step 17B is formed which protrudes toward the flow path 19 when viewed from the open end 18B of the second socket 16B. The multi-layer joint 2 has a pipe axis O3. The pipe axis O3 extends in a direction from the open end 18A of the first socket portion 16A toward the open end 18B of the second socket portion 16B.

[0032] The joint body 11 has a gate mark G on its outer surface. 3, the gate mark G is on a virtual plane P2. In addition, the gate mark G is located on the tube axis O3 in a side view. Similarly, the gate mark G is located on the tube axis O3 in a rear view.

[0033] In the first receiving portion 16A, the distance in the tube axis O3 direction from the gate mark G to the open end 18A is L3. The distance in the tube axis O3 direction from the gate mark G to the first step portion 17A is Z3. In the second receiving portion 16B, the distance in the tube axis O3 direction from the gate mark G to the open end 18B is L4. The distance in the tube axis O3 direction from the gate mark G to the second step portion 17B is Z4.

[0034] In the multilayer joint 2, the ratio of the distance Z4 to the distance Z3 (also referred to as the "ratio Z4 / Z3") is 0.90 to 1.10, preferably 0.95 to 1.05, more preferably 0.98 to 1.02, and most preferably 1.00. When the ratio Z4 / Z3 is within the above numerical range, the difference between the distance from the gate of the mold forming the multilayer joint 2 to the first socket portion 16A and the distance from the gate to the second socket portion 16B is small. Therefore, there is no difference in the cooling speed or flow time of the resin composition for each socket portion, and the resin composition is thermally shrunk uniformly. As a result, the water-stopping performance of each socket portion becomes equal, and the water-stopping property of the multilayer joint 2 can be further improved.

[0035] The distance Z3 is appropriately determined depending on the application of the multilayer joint 2, and is, for example, preferably 20 to 500 mm, more preferably 30 to 400 mm, and even more preferably 40 to 300 mm. When the distance Z3 is equal to or greater than the above-mentioned lower limit, the joint body 11 is easily molded. When the distance Z3 is equal to or less than the above-mentioned upper limit, the distance to the first step 17A does not become too long, and a weld line is unlikely to be formed. This further improves the watertightness of the multilayer joint 2. Distance Z4 is similar to distance Z3. Distance Z3 and distance Z4 can be measured using a vernier caliper, a curved ruler, or the like.

[0036] In the multilayer joint 2, the ratio of the distance L4 to the distance L3 (also referred to as the "ratio L4 / L3") is 0.90 to 1.10, preferably 0.95 to 1.05, more preferably 0.98 to 1.02, and most preferably 1.00. When the ratio L4 / L3 is within the above numerical range, the difference between the distance from the gate of the mold forming the multilayer joint 2 to the opening end 18A of the first socket portion 16A and the distance from the gate to the opening end 18B of the second socket portion 16B is small. Therefore, there is no difference in the cooling speed or flow time of the resin composition for each socket portion, and the resin composition is thermally shrunk uniformly. As a result, the water-stopping performance of each socket portion becomes equal, and the water-stopping performance of the multilayer joint 1 can be further improved.

[0037] The distance L3 is appropriately determined depending on the application of the multilayer joint 2, and is, for example, preferably 30 to 800 mm, more preferably 40 to 600 mm, and even more preferably 50 to 400 mm. When the distance L3 is equal to or greater than the above lower limit, the multilayer joint 2 is easily molded. When the distance L3 is equal to or less than the above upper limit, the distance to the opening end 18A does not become too long, and a weld line is unlikely to be formed. This allows the water-stopping property of the multilayer joint 2 to be further improved. Distance L4 is similar to distance L3. Distance L3 and distance L4 can be measured using a vernier caliper, a curved ruler, or the like.

[0038] Length L of the joint body 11 in the pipe axis O3 direction 11 The length L is appropriately determined depending on the application of the multilayer joint 2, and is, for example, preferably 40 to 1000 mm, more preferably 60 to 800 mm, and further preferably 80 to 600 mm. 11 When the length L is equal to or greater than the lower limit, the joint body 11 is easy to form. 11 When it is equal to or less than the above upper limit value, the strength of the joint body 11 can be further increased. Length L 11 can be measured using a vernier caliper, a curved ruler, etc.

[0039] Wall thickness T of fitting body 1111 The thickness T of the joint body 11 is appropriately determined depending on the application of the multi-layer joint 2, and is preferably 1 to 30 mm, more preferably 2 to 20 mm, and further preferably 3 to 10 mm, for example. 11 When the thickness T of the joint body 11 is equal to or greater than the lower limit, the strength of the joint body 11 can be further increased. 11 When the ratio is equal to or less than the upper limit, the amount of the main body resin used can be reduced. Wall thickness T of fitting body 11 11 can be obtained, for example, by cutting the joint body 11 at the imaginary plane P2 and measuring with a vernier caliper, a curved ruler, or the like.

[0040] Opening diameter R of first receiving portion 16A 16A is appropriately determined depending on the application of the multi-layer joint 2, and is, for example, preferably 20 to 300 mm, more preferably 30 to 200 mm, and further preferably 40 to 100 mm. 16A When the opening diameter R is equal to or larger than the lower limit, it is easy to form the opening diameter R of the first receiving member 20C integrally with the first receiving member 20C. 16A When is equal to or less than the above upper limit value, the water-stopping property of the first receiving portion 16A can be further improved. Opening diameter R of second receiving portion 16B 16B is the opening diameter R of the first receiving portion 16A. 16A is the same as: Opening diameter R 16A , opening diameter R 16B can be measured using a vernier caliper, a curved ruler, etc.

[0041] Height H of the first step 17A 17A The height H is appropriately determined depending on the application of the multilayer joint 2, and is, for example, preferably 1 to 20 mm, more preferably 2 to 15 mm, and further preferably 3 to 10 mm. 17A If the height H is equal to or greater than the lower limit, the pipe can be easily fixed. 17A When the thickness is equal to or less than the upper limit, the strength of the first receiving portion 16A can be further increased. In addition, the height H 17A refers to the distance from the inner surface of the joint body 11 at the first step 17A to the inner surface of the first socket portion 16A at the first step 17A. Height H of the second step 17B 17Bis the height H of the first step 17A 17A is the same as: Height H 17A , height H 17B can be measured using a vernier caliper, a curved ruler, etc.

[0042] The thickness T of the first receiving portion 16A 16A is appropriately determined depending on the application of the multilayer joint 2, and is, for example, preferably 1 to 20 mm, more preferably 2 to 15 mm, and further preferably 3 to 10 mm. 16A When the thickness T is equal to or greater than the lower limit, the strength of the first receiving portion 16A can be further increased. 16A When the ratio is equal to or less than the upper limit, the amount of the main body resin used can be reduced. The thickness T of the second receiving portion 16B 16B is the thickness T of the first receiving portion 16A. 16A is the same as: Wall thickness T 16A , wall thickness T 16B can be measured using a vernier caliper, a curved ruler, etc.

[0043] In the multi-layer joint 2, the position of the gate mark G can be adjusted by the position of the gate provided in the mold when molding the multi-layer joint 2.

[0044] As shown in Fig. 4, the first receiving member 20A has a cylindrical body portion 21 and an annular portion 23 that protrudes inward from one open end 22a of the body portion 21. The annular portion 23 is located at the boundary between the joint body 10 and the first receiving portion 12A, and forms the surface of the step portion 13A of the multilayer joint 1. The first receiving member 20A has a tube axis O1. The tube axis O1 extends in a direction from one open end 22a of the body portion 21 toward the other open end 22b.

[0045] A water-stopping protrusion 24 and a water-stopping recess 25 are formed on the outer surface of the annular portion 23. The water-stopping protrusion 24 goes around the opening of the annular portion 23. The water-stopping recess 25 goes around the outer edge of the water-stopping protrusion 24. When forming the multilayer joint 1, the water-stopping convex portion 24 bites into the main body resin, and the main body resin enters the water-stopping concave portion 25, thereby preventing water flowing through the flow path 15 from penetrating into the boundary between the annular portion 23 and the main body resin.

[0046] Two or more fitting protrusions 26 and two or more fitting recesses 27 are formed on the outer surface of the body portion 21. The fitting protrusions 26 run around the outer surface of the body portion 21. The fitting recesses 27 run around the outer surface of the body portion 21. The number of fitting protrusions 26 is not particularly limited, but is preferably 2 to 10, and more preferably 3 to 8. When the number of fitting protrusions 26 is equal to or greater than the above lower limit, the bond with the body resin can be improved. When the number of fitting protrusions 26 is equal to or less than the above upper limit, the first receiving member 20A can be molded more easily. The number of fitting recesses 27 is the same as the number of fitting protrusions 26 .

[0047] The thickness T of the body 21 of the first receiving member 20A 21 The thickness T is appropriately determined depending on the application of the multilayer joint 1, and is preferably 1 to 20 mm, more preferably 2 to 15 mm, and further preferably 3 to 10 mm. 21 When the thickness T is equal to or greater than the lower limit, the strength of the first receiving member 20A can be further increased. 21 When is equal to or less than the above upper limit value, the first receiving member 20A can be made lighter. The thickness T of the body 21 of the first receiving member 20A 21 can be measured using a vernier caliper, a curved ruler, etc.

[0048] Width L of the annular portion 23 of the first receiving member 20A 23 The width L of the annular portion 23 is appropriately determined depending on the application of the multilayer joint 1, and is preferably 1 to 20 mm, more preferably 2 to 15 mm, and further preferably 3 to 10 mm, for example. 23 When the width L of the annular portion 23 is equal to or greater than the above lower limit, the water-stopping property of the multilayer joint 1 can be further improved. 23 When is equal to or less than the above upper limit value, the strength of the first receiving member 20A can be further increased.

[0049] The second receiving member 20B has the same shape, material, and dimensions as the first receiving member 20A. Moreover, the first receiving member 20C and the second receiving member 20D have the same shape and are made of the same material as the first receiving member 20A.

[0050] The first receiving member 20A is made of resin. Examples of resins that form the first receiving member 20A include hard polyvinyl chloride resins, ABS (acrylonitrile-butadiene-styrene copolymer) resins, acrylic resins, polycarbonate resins, polyethylene terephthalate resins, and urethane resins. As the resins that form the first receiving member 20A, hard polyvinyl chloride resins, ABS resins, and acrylic resins are preferred, and hard polyvinyl chloride resins and ABS resins are more preferred, because they are more likely to exhibit water-stopping performance due to thermal shrinkage of the resin. The resin forming the first receiving member 20A may be used alone or in combination of two or more kinds.

[0051] The first receiving member 20A is manufactured by injection molding. During injection molding, a first resin composition, which is the raw material of the first receiving member 20A, is injected into a mold from a gate. The first resin composition flows inside the mold and is cooled and solidified. After the first resin composition has solidified, it is demolded from the mold to obtain the first receiving member 20A.

[0052] Next, the first receiving member 20A and the second receiving member 20B are placed in a new mold for the multilayer joint 1, and the resin composition of the main body resin is injected into the mold from the gate. The resin composition of the main body resin flows inside the mold and is cooled and solidified. After the resin composition of the main body resin has solidified, it is demolded from the mold to obtain a multilayer joint 1 in which the first receiving member 20A is inserted into the inner surface of the first receiving portion 12A and the second receiving member 20B is inserted into the inner surface of the second receiving portion 12B. If the distance from the gate to each receiving port is equal when injecting the resin composition of the main resin, the resin composition of the main resin will have the same cooling speed and flow time for each receiving port, and the resin composition of the main resin will thermally shrink uniformly. As a result, the watertightness of each receiving port will be equal, and the watertightness of the multi-layer joint 1 can be improved. The multi-layer joint 2 can be manufactured in a similar manner.

[0053] The joint body 10 and the socket outer layer 51 are made of resin. Examples of the resin forming the joint body 10 and the socket outer layer 51 (i.e., the body resin) include fluorine-based resins, polyphenylsulfone-based resins, polyphenylene sulfide-based resins, olefin-based resins, etc. As the body resin, fluorine-based resins and polyphenylsulfone-based resins are preferred from the viewpoint of excellent impact resistance and chemical resistance. The main resin may be used alone or in combination of two or more kinds.

[0054] FIG. 5 is a partial cross-sectional view of the piping system 100 near the first receiving port 12A. As shown in Fig. 5, the piping system 100 of the present invention includes a multilayer joint 1, a first receiving member 20A, and a first pipe 30A. In Fig. 5, the first receiving member 20A is fitted to the receiving outer layer 51 of the first receiving portion 12A via the fitting convex portion 26 and the fitting concave portion 27. The first pipe 30A is disposed inside the first receiving portion 12A. Water (drainage) flows through the flow path of the first pipe 30A and the flow path 15 of the multilayer joint 1. In the vicinity of the step portion 13A, the water-stopping convex portion 24 bites into the main body resin, and the main body resin enters the water-stopping concave portion 25, thereby preventing the water flowing through the flow path 15 from penetrating into the boundary between the annular portion 23 and the main body resin.

[0055] In the piping system 100, a second piping 30B is disposed inside the second receiving portion 12B (not shown). In the second receiving portion 12B, the second receiving member 20B is fitted into the receiving outer layer 51 via the fitting convex portion 26 and the fitting concave portion 27 (not shown). In the vicinity of the step portion 13B, the water-stopping convex portion 24 bites into the main body resin, and the main body resin enters the water-stopping concave portion 25, thereby preventing the water flowing through the flow path 15 from penetrating into the boundary between the annular portion 23 and the main body resin.

[0056] The thickness T of the annular portion 23 of the first receiving member 20A 23 The wall thickness T of the annular portion 23 is appropriately determined depending on the application of the multilayer joint 1, and is preferably 1 to 15 mm, more preferably 2 to 12 mm, and further preferably 3 to 10 mm, for example. 23When the thickness T of the annular portion 23 is equal to or greater than the lower limit, the strength of the annular portion 23 can be further increased. 23 When is equal to or less than the above upper limit value, the first receiving member 20A can be made lighter.

[0057] It is preferable that the first pipe 30A has at least a pipe inner layer 31 facing the flow path and a pipe outer layer 32 located on the outer surface. By having the first pipe 30A have the pipe inner layer 31 and the pipe outer layer 32, various functions can be imparted to the first pipe 30A.

[0058] Wall thickness T of first pipe 30A 30A The thickness T is appropriately determined depending on the application of the first pipe 30A, and is, for example, preferably 2 to 30 mm, more preferably 3 to 20 mm, and further preferably 4 to 15 mm. 30A When the thickness T is equal to or greater than the lower limit, the strength of the first pipe 30A can be further increased. 30A When it is equal to or less than the above upper limit, the bonding strength with the multilayer joint 1 can be further increased.

[0059] Thickness T of the inner layer 31 of the pipe 31 The wall thickness T of the first pipe 30A is appropriately determined depending on the application of the first pipe 30A, and is preferably 1 to 15 mm, more preferably 2 to 12 mm, and further preferably 3 to 10 mm, for example. 31 When the thickness T of the inner pipe layer 31 is equal to or greater than the lower limit, it is easy to provide various functions to the inner pipe layer 31. 31 When it is equal to or less than the above upper limit, various functions can be easily imparted to the pipe outer layer 32 .

[0060] Thickness T of the outer layer 32 of the pipe 32 The thickness T of the outer layer 32 of the first pipe 30A is appropriately determined depending on the application of the first pipe 30A, and is preferably 1 to 20 mm, more preferably 2 to 15 mm, and further preferably 3 to 10 mm. 32 When the thickness T of the outer layer 32 is equal to or greater than the lower limit, it is easy to provide various functions to the outer layer 32. 32 When it is equal to or less than the above upper limit, it is easy to impart various functions to the inner layer 31 of the pipe.

[0061] Examples of the resin forming the pipe inner layer 31 include fluorine-based resin, polyphenylsulfone-based resin, polyphenylene sulfide-based resin, olefin-based resin, etc. When the pipe inner layer 31 is formed of these resins, the first pipe 30A has excellent impact resistance and chemical resistance. Examples of the resin that forms the piping outer layer 32 include vinyl chloride resins. When the resin that forms the piping outer layer 32 is vinyl chloride resin, it is easy to bond with the abutting first receiving member 20A. This further improves the watertightness of the piping system 100.

[0062] The end face of the first pipe 30A abuts against the annular portion 23. At this time, the end face of the pipe inner layer 31 abuts against the joint body 10. Also, the pipe outer layer 32 abuts against the first receiving member 20A. The pipe inner layer 31 and the joint body 10 are formed of the same type of resin. Also, the pipe outer layer 32 and the first receiving member 20A are formed of the same type of resin. Therefore, a gap is unlikely to be formed between the end face of the first pipe 30A and the multilayer joint 1, and the intrusion of water flowing through the flow path 15 can be suppressed. As a result, the watertightness of the piping system 100 can be further improved.

[0063] The layer structure, shape, material, and dimensions of the second pipe 30B are similar to those of the first pipe 30A.

[0064] The multilayer joint 1 of this embodiment has a gate mark G on the imaginary plane P1 and on the pipe axis O of the joint body 10 when viewed from behind. Therefore, there is no difference in the cooling speed or flow time of the resin composition for each socket, and the resin composition thermally shrinks uniformly. As a result, the watertightness of each socket becomes equal, and the watertightness of the multilayer joint 1 can be further improved.

[0065] Although one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and changes, combinations, deletions, etc. of the configuration are also included within the scope that does not deviate from the gist of the present invention. In the above-described embodiment, two or more mating protrusions 26 and mating recesses 27 are formed on the outer surface of body 21 of first receiving member 20A. However, the present invention is not limited to this, and there may be only one mating protrusion or mating recess formed on the outer surface of the body, and no mating protrusions or mating recesses may be formed on the outer surface of the body of the receiving member. From the viewpoint of further increasing the adhesive strength between the receiving member and the main body resin, it is preferable that a mating protrusion or mating recess is formed on the outer surface of the body of the receiving member, and it is more preferable that two or more mating protrusions or mating recesses are formed on the outer surface of the body. In the above embodiment, the gate mark G is formed on the back side of the joint body 10 of the multilayer joint 1. However, the present invention is not limited to this, and the gate mark G may be formed on the front side of the joint body 10. However, if the gate mark G is formed on the side of the joint body 10, the gate mark G will not be located on the pipe axis O of the joint body 10, and the distance from the gate mark G to the opening end of the first receiving portion 12A on the side where the gate mark G is formed and the opening end on the side where the gate mark G is not formed will not be equal. Therefore, in the first receiving portion 12A, the thermal shrinkage of the resin composition may vary, and the water-stopping performance may vary. Similarly, in the second receiving portion 12B, the distance from the gate mark G to the opening end on the side where the gate mark G is formed and the opening end on the side where the gate mark G is not formed will not be equal. Therefore, in the second receiving portion 12B, the thermal shrinkage of the resin composition may vary, and the water-stopping performance may vary. Therefore, it is preferable that the gate mark G is not formed on the side surface of the joint body 10. EXAMPLES

[0066] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The raw materials and evaluation methods used in each of the examples and comparative examples are as follows.

[0067] <Coupling body> Socket of the shape shown in Figure 3, made of homopolypropylene resin (manufactured by SCG Plastics). <Receiving part> The receiving part has the shape shown in Figure 4 and is made of heat-resistant polyvinyl chloride resin (manufactured by Yamanashi Sekisui Co., Ltd.).

[0068] [Example 1] The receiving member was injection molded using a resin composition (first resin composition) mainly composed of heat-resistant polyvinyl chloride. The molded receiving member was inserted into the core of the joint body mold, and a resin composition (resin composition of the main body resin) mainly composed of polypropylene (homopolypropylene) was injection molded. At this time, the receiving member was inserted so that the inner surface of the joint body mold had a clearance (gap) of at least 0.5 mm with respect to the outer surface of the receiving member. The clearance was covered by the homopolypropylene that flowed in during injection molding, and a receiving outer layer was formed. The obtained multilayer joint had a socket shape as shown in FIG. 3. The multilayer joint had a nominal diameter of 40A, and the opening diameter of the receiving part (receiving inner diameter), the inner diameter of the joint body, and the outer diameter of the joint were produced in accordance with the standard dimensions described in JIS K6739:2007 "Drainage Rigid Polyvinyl Chloride Pipe Joints". The positions of the gate marks were Z3=38.5 mm and Z4=36.5 mm in FIG. 3.

[0069] [Comparative Example 1] A socket-shaped multilayer joint was produced in the same manner as in Example 1, except that the gate position of the joint main body mold was adjusted so that the positions of the gate marks of the multilayer joint were Z3 = 40.5 mm and Z4 = 34.5 mm in Figure 3.

[0070] [Watertightness evaluation] The sockets obtained in Example 1 and Comparative Example 1 were used as test specimens, and two of the sockets of each test specimen were blocked with a blocking jig. A pipe with an adhesive applied to one end was inserted into the remaining socket and joined, and the adhesive was dried at room temperature (23°C) for 24 hours. Thereafter, in order to alleviate the shrinkage force due to homopolypropylene, the specimen was cured in an oven at 110°C for 5 hours to form a piping structure. Thereafter, a water pressure of 0.35 MPa was applied to the other end of the pipe and maintained for 2 minutes, and the presence or absence of water leakage from the joint between the receiving part and the pipe was visually confirmed. The watertightness was evaluated according to the following evaluation criteria. The results are shown in Table 1. Evaluation Criteria ○: No leakage from joints. ×: Water leakage from joints.

[0071] [Table 1]

[0072] As shown in Table 1, Example 1 to which the present invention was applied was evaluated as "good" in terms of water stoppage ability. On the other hand, in Comparative Example 1 in which the gate mark was located closer to the second receiving portion 16B and the ratio Z4 / Z3 was less than 0.90, the waterproofing performance was evaluated as "X". From the above results, it was found that the present invention can further improve the water stopping properties. [Explanation of symbols]

[0073] 1,2 Multi-layer joints 10,11 Fitting body 10A, 10B, 11A, 11B Opening of fitting body 12A, 16A First socket 12B, 16B Second socket 13A, 17A First step 13B, 17B Second step 14A, 18A Open end of first socket 14B, 18B Open end of second socket 15,19 Flow path 20A, 20C First receiving member 20B, 20D Second receiving member 21 Torso 22a One open end 22b The other open end 23 Circular Ring 24 Water-stopping protrusion 25 Water-stopping recess 26 Fitting protrusion 27 Fitting recess 30A First Pipe 30B Second piping 31 Pipe Inner Layer 32 Piping outer layer 51 Socket outer layer 52 Inner layer of socket 100 Piping System O,O3 Pipe axis of joint body O1 First tube axis O2 Second tube axis L1,L2,Z1,Z2 distance G Gate mark P1,P2 Virtual plane

Claims

1. A tubular joint body having a flow path therein and openings at both ends; A first socket portion surrounding an opening at one end of the joint body and a second socket portion surrounding an opening at the other end of the joint body, The first socket portion and the second socket portion are symmetrical with respect to a virtual plane, a first annular step portion protruding toward the flow path is formed at a boundary between the joint body and the first receiving portion, a second annular step portion protruding toward the flow path is formed at a boundary between the joint body and the second receiving portion, the first socket portion has a first socket member integrally formed on an inner surface thereof; the second socket portion has a second socket member integrally formed on an inner surface thereof; The joint body has a gate mark on an outer surface, The gate mark is located on the virtual plane and on the pipe axis of the joint body in a rear view, It is an insert molding product, The first receiving member and the second receiving member each have a cylindrical body portion, a circular ring portion that protrudes inward from one open end of the body portion, and a convex portion that is formed on an outer surface of the circular ring portion and circumscribes an opening of the circular ring portion, an inner edge of the protrusion of the first receiving member is located outside an outer edge of the opening at the one end; A multi-layer joint (excluding those having a joint body in which a protrusion higher than a gate mark is erected around a gate mark) in which the inner edge of the convex portion of the first receiving member is located outside the outer edge of the opening at the other end.

2. Distance Z from the gate mark to the first step １ The distance Z from the gate mark to the second step portion ２ Ratio (Ratio Z ２ / Z １ 2. The multilayer joint according to claim 1, wherein the ratio of the cross-sectional area to the cross-sectional area of ​​the multilayer joint is 0.90 to 1.

10.

3. Distance L from the gate mark to the opening end of the first receiving portion １ The distance L from the gate mark to the opening end of the second receiving portion ２ Ratio (Ratio L ２ / L １ 3. The multilayer joint according to claim 1, wherein the ratio of the cross-sectional area to the cross-sectional area of ​​the multilayer joint is 0.90 to 1.

10.

4. A multilayer joint according to any one of claims 1 to 3; a first pipe disposed inside the first receiving member; a second pipe disposed within the second receiving member, The first pipe and the second pipe have at least a pipe inner layer facing the flow path and a pipe outer layer located on an outer surface, the inner layer of the pipe is formed of a resin including at least one selected from a fluorine-based resin, a polyphenylsulfone-based resin, a polyphenylene sulfide-based resin, and an olefin-based resin; the outer layer of the pipe contains a vinyl chloride resin, an end surface of the first pipe abuts against the first step portion, and an outer pipe layer of the first pipe abuts against an inner surface of the first receiving member; A piping system, wherein an end surface of the second pipe abuts against the second step portion, and the pipe outer layer of the second pipe abuts against an inner surface of the second receiving member.

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