JP2020165506A - Drainpipe - Google Patents

Abstract

To provide a drainpipe which is excellent in inter-layer stability while being a multilayer pipe having a hard polyvinyl chloride system resin outer layer and an anticorrosive inner layer.SOLUTION: A drainpipe for use in the drainage at a temperature T°C (here, T≥60) includes: an inner layer constituted of resin selected from a group composed of a polyolefin resin, a fluorine resin, a polyphenyl sulfonic resin, and a polyphenyl sulfide resin; an outer layer formed outside the inner layer, and constituted of a hard polyvinyl system resin; and an adhesive which is charged between the outer layer and the inner layer. The drainpipe whose weighting deflection temperature of a resin of 0.45 Mpa constituting the inner layer is T×0.85°C of higher is excellent in inter-layer stability.SELECTED DRAWING: Figure 1

Description

The present invention relates to a drainage pipe having a multi-layer pipe structure used for high-temperature drainage and having excellent interlayer stability.

Conventionally, stainless steel and resin have been used as piping materials. Since the stainless steel pipe is made of metal, it has extremely excellent heat resistance. On the other hand, stainless steel pipes also have disadvantages such as insufficient corrosion resistance, heavy weight and poor handleability, and poor workability because welding or threaded connection is required for connection. For this reason, resin pipes that are lightweight and easy to handle are being replaced, except for pipes for special purposes that are exposed to high temperature conditions such as for nuclear power plants.

Polyolefin-based resin pipes such as polypropylene pipes and polyethylene pipes are widely used as resin pipes having excellent corrosion resistance and can be provided at low cost. An example of the characteristics of the polyolefin-based resin tube is that it needs to be connected by electric fusion because of its extremely high corrosion resistance that is not attacked by a solvent. Recently, the connection technology of polyolefin-based resin pipes has been advanced, and as described in Patent Document 1, an electric fusion joint that copes with variations in fusion performance in an electric fusion connection has been proposed.

Another example of the characteristics of the polyolefin-based resin tube is flexibility. Flexibility is one of the most important properties of polyolefin resin tubes. Patent Document 2 discloses a technique for eliminating the need for connection by electrofusion even though it is a polyolefin resin tube. Specifically, an adhesive layer made of a soft vinyl chloride resin is provided on the outer periphery of the polyolefin resin tube to bond the polyolefin resin tube. The flexibility of the polyolefin resin tube is maintained by forming the layer as thin as possible, preferably with a thickness of 0.2 mm to 0.5 mm.

JP-A-2018-162858 Japanese Unexamined Patent Publication No. 2013-117290

Polyolefin-based resin pipes have been used for water distribution pipes due to their excellent corrosion resistance and flexibility. Even in the case of forming a multilayer tube in which resin layers of different materials are laminated, as in the polyolefin resin tube disclosed in Patent Document 2, soft chloride which is a different material layer is formed on the outside of the polyolefin resin tube. The different material layer is configured so as not to impair the corrosion resistance and flexibility characteristic of the polyolefin tube, such as laminating the vinyl layer as thinly as possible.

The present inventor has conceived a pipe (high temperature drainage pipe) specialized for high temperature drainage of 60 ° C. or higher. First, as a premise, since wastewater contains various corrosion factors together with water, it is considered that a polyolefin-based resin pipe having high corrosion resistance is suitable. However, when the water distribution pipe is used for drainage, the gradient management is important in order to effectively drain the water. Therefore, the flexibility of the polyolefin resin pipe, that is, the poor rigidity, makes the gradient control. On the contrary, I faced the problem of becoming an obstacle. Further, due to the flexibility of the polyolefin resin pipe, that is, the poor rigidity, it may be necessary to shorten the support interval and the expansion / contraction treatment interval as compared with the polyvinyl chloride resin pipe, and the number of members required for construction and the number of members required for construction There is also the problem of increased man-hours. In other words, it was found that in the application of polyolefin resin pipes to drainage applications, new problems in construction such as difficulty in gradient management and a large number of construction members and man-hours arise as unique problems.

Therefore, for the purpose of improving workability, we conceived a drainage pipe in which a polyolefin-based resin layer was provided inside the hard polyvinyl chloride-based resin pipe to provide rigidity to the entire water distribution pipe. However, in high-temperature drainage applications, the inner layer may peel off at the end of the pipe depending on the heat resistance of the inner layer material, and further, the outer layer's hard polyvinyl chloride resin and the inner layer's polyolefin resin It was found that the inevitable difference in the coefficient of linear expansion between them spurred the occurrence of this phenomenon and made it more prominent. The peeling of the inner layer means that high-temperature drainage enters the gap that is inevitably generated between the pipe end surface of the drainage pipe and the inner wall surface of the joint at the connection part between the drainage pipe and the joint, and the pipe end surface is exposed to the high-temperature drainage. Caused by.

Therefore, an object of the present invention is to provide a drainage pipe which is a multi-layer pipe having a hard polyvinyl chloride resin outer layer and a corrosion-resistant inner layer but has excellent interlayer stability.

As a result of diligent studies, the present inventor has placed a drainage pipe used for drainage at a temperature of T ° C. (however, T ≧ 60) on the outside of a resin pipe having excellent corrosion resistance such as a polyolefin resin pipe, via an adhesive layer. The inner layer can be peeled off by providing a layer of a polyvinyl chloride resin and selecting a resin having a weight deflection temperature at 0.45 MPa of T × 0.85 ° C. or higher as the resin constituting the inner layer. It has been found that the interlayer stability that is remarkably suppressed can be exhibited. Although it is known that the deflection temperature under load is an index of heat resistance, it does not represent the upper limit temperature of the material because its value varies depending on the value of the load. Moreover, the drainage has no pressure on the inner wall of the drainage pipe. Therefore, when drainage is performed at a temperature of T ° C. (however, T ≧ 60), the inner layer resin is stabilized between layers by selecting a resin having a weight deflection temperature of T × 0.85 ° C. or higher at 0.45 MPa. It was completely unexpected that the sex was significantly improved. The present invention has been completed by further studies based on this finding. That is, the present invention provides the inventions of the following aspects.

Item 1. A drainage pipe used for drainage at a temperature of T ° C. (however, T ≧ 60).
It is composed of an inner layer composed of a resin selected from the group consisting of a polyolefin resin, a fluororesin, a polyphenylsulfone resin, and a polyphenylsulfone resin, and a rigid polyvinyl chloride resin provided outside the inner layer. An outer layer to be formed and an adhesive layer provided between the outer layer and the inner layer are included.
A drainage pipe having a weight deflection temperature of the resin constituting the inner layer at 0.45 MPa of T × 0.85 ° C. or higher.
Item 2. Item 2. The drainage pipe according to Item 1, which is used for drainage at a temperature of T ° C. (where T ≧ 80).
Item 3. Item 2. The drainage pipe according to Item 2, wherein the resin constituting the inner layer is polypropylene, and the hard polyvinyl chloride resin constituting the outer layer is a chlorinated polyvinyl chloride resin.
Item 4. Item 2. The drainage pipe according to any one of Items 1 to 3, wherein the melting temperature of the adhesive layer is 95 ° C. or higher.
Item 5. Item 2. The drainage pipe according to any one of Items 1 to 4, wherein the ratio of the thickness of the inner layer to the total thickness is 0.06 to 0.44.
Item 6. Item 2. The drainage pipe according to any one of Items 1 to 5, wherein the inner layer has a thickness of 0.3 to 2.2 mm.
Item 7. Item 2. The drainage pipe according to any one of Items 1 to 6, wherein the linear expansion coefficient of the inner layer is 10 × 10 ^-5 / ° C. or higher, and the linear expansion coefficient of the outer layer is 7.5 × 10 ^-5 / ° C. or lower. ..
Item 8. Item 2. The drainage pipe according to any one of Items 1 to 7, wherein the inner layer includes a fiber-reinforced resin layer and a fiber-free layer provided inside the fiber-reinforced resin layer.

According to the drainage pipe of the present invention, there is provided a drainage pipe which is a multi-layer pipe having a hard polyvinyl chloride resin outer layer and a corrosion-resistant inner layer, but has excellent interlayer stability. Therefore, even if it is used for high-temperature drainage at 60 ° C. or higher, peeling of the inner layer can be suppressed.

The cross-sectional view of the drainage pipe which concerns on 1st Embodiment is shown. The cross-sectional view of the drainage pipe which concerns on 2nd Embodiment is shown.

The drainage pipe of the present invention is a drainage pipe used for drainage at a specific temperature, and is an inner layer made of a specific resin and an outer layer made of a hard polyvinyl chloride resin provided outside the inner layer. And an adhesive layer provided between the outer layer and the inner layer, and the weighted deflection temperature of the resin constituting the inner layer at 0.45 MPa has a specific relationship with the temperature of the wastewater. It is characterized by. The drainage pipe of the present invention will be described in detail below.

First Embodiment FIG. 1 shows a first embodiment of the drainage pipe of the present invention. The drainage pipe 100a shown in FIG. 1 has an inner layer 110, an outer layer 120, and an adhesive layer 130 interposed between them.

Inner layer The inner layer 110 is made of a corrosion-resistant resin, and specifically, is made of a resin selected from the group consisting of a polyolefin resin, a fluororesin, a polyphenylsulfone resin, and a polyphenylsulfone resin. By forming the inner layer 110 with these resins, the drainage pipe 100a is provided with excellent corrosion resistance to drainage.

The polyolefin-based resin is not particularly limited. For example, polyethylene, polypropylene, polybutene and the like can be mentioned, and polyethylene and polypropylene are preferably mentioned. These polyolefin-based resins may be used alone or in combination of two or more.

Examples of polyethylene include homopolymers and copolymers of ethylene, and preferably copolymers. Examples of the ethylene copolymer include an ethylene-α-olefin copolymer obtained by copolymerizing an α-olefin, and examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene and 4-methyl-. Examples thereof include 1-pentene and 1-octene. These α-olefins may be used alone or in combination of two or more. The copolymerization ratio of α-olefin is 5 mol% or less. More specific examples of polyethylene include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE) and the like. These polyethylenes may be used alone or in combination of two or more.

Examples of polypropylene include homopolypropylene homopolymers and copolymers of propylene. Examples of the propylene copolymer include a propylene-α-olefin copolymer obtained by copolymerizing an α-olefin, and examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene and 4-methyl-. Examples thereof include 1-pentene and 1-octene. These α-olefins may be used alone or in combination of two or more. The copolymerization ratio of the α-olefin is less than 10 mol%, preferably 9 mol% or less. More specific examples of polypropylene include block polypropylene and random polypropylene. These polypropylenes may be used alone or in combination of two or more.

The fluororesin is not particularly limited. For example, examples of the fluororesin include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and polychlorotrifluoroethylene. (PCTFE), polyvinylidene fluoride (PVdF), tetrafluoroethylene-ethylene copolymer (ETFE), polyvinyl fluoride (PVF), chlorotrifluoroethylene-ethylene copolymer (ECTFE) and the like. PTFE includes a tetrafluoroethylene homopolymer and a copolymer of tetrafluoroethylene and a comonomer such as perfluorovinyl ether, hexafluoropropylene, chlorotrifluoroethylene, vinylidene fluoride, and trifluoroethylene. These commonomers may be used alone or in combination of two or more. The copolymerization ratio of the comonomer is 1% by weight or less.

Among the above-mentioned polyolefin resins, polypropylene is preferable, and homopolypropylene is more preferable.

Examples of the homopolypropylene include those having a density of preferably 900 to 910 kg / m ³ . The density is a measured value obtained at a measured temperature of 23 ° C. in accordance with ISO 1183.

Further, the resin constituting the inner layer 110 has a deflection temperature under load at 0.45 MPa of T × 0.85 ° C. or higher when the temperature of the drainage is T ° C. This imparts excellent interlayer stability to the drain pipe. From the viewpoint of obtaining more excellent interlayer stability, the deflection temperature under load at 0.45 MPa is preferably T ° C. or higher.

More specifically, when 60 ≦ T <80, preferably 60 ≦ T ≦ 70, and more preferably 60 ≦ T ≦ 65, the deflection temperature under load at 0.45 MPa is preferably T ° C. or higher, more preferably. Is 1.6 × T ° C. or higher. Further, when T ≧ 80, for example, 85 ≦ T ≦ 100, preferably 85 ≦ T ≦ 95, more preferably 87 ≦ T ≦ 93, the deflection temperature under load at 0.45 MPa is preferably T ° C. or higher. Preferably, it is 1.1 × T ° C. or higher.

Since the higher the deflection temperature under load at 0.45 MPa, the more preferable it is, the upper limit within the range of the deflection temperature under load is not particularly limited, but the upper limit is, for example, 150 ° C. or lower, preferably 130 ° C. or lower, more preferably 110 ° C. The following can be mentioned.

The deflection temperature under load at 0.45 MPa is a temperature measured in accordance with the B method of JIS K7191.

Examples of the coefficient of linear expansion of the inner layer 110 include 10 × 10 ^-5 / ° C. or higher. From the viewpoint of obtaining more preferable interlayer stability, the coefficient of linear expansion of the inner layer 110 is preferably 10 × 10 ^-5 to 15 × 10 ^-5 / ° C, more preferably 10 × 10 ^{-5 to} 14 × 10 ^-5 / ° C. ° C., more preferably 10 × 10 ^{-5 to} 13 × 10 ^-5 / ° C, and even more preferably 10 × 10 ^{-5 to} 12 × 10 ^-5 / ° C.

Originally, the larger the coefficient of linear expansion of the inner layer 110 (that is, farther from the coefficient of linear expansion of the rigid vinyl chloride resin), the lower the interlayer stability tends to be, but the drain pipe of the present invention has excellent interlayer stability. Therefore, even if the linear expansion coefficient of the inner layer 110 is relatively large, the inter-story stability can be effectively obtained. From this point of view, a preferable example of the coefficient of linear expansion of the inner layer 110 is preferably 10.5 × 10 ^-5 to 15 × 10 ^-5 / ° C, more preferably 11 × 10 ^-5 to 15 × 10 ^{−. 5} / ° C is mentioned. The coefficient of linear expansion is a value obtained by measurement according to ASTMD696.

Examples of the thickness t1 of the inner layer 110 include 0.06 to 0.44 as a ratio (t1 / t) to the total thickness t. From the viewpoint of obtaining more preferable interlayer stability, the ratio of the thickness t1 of the inner layer 110 is preferably 0.1 to 0.44, more preferably 0.15 to 0.44. The specific thickness t1 of the inner layer 110 may vary depending on the nominal diameter of the drain pipe 100a, and may be, for example, 0.3 to 2.2 mm. From the viewpoint of obtaining more preferable interlayer stability, the specific thickness t1 of the inner layer 110 is preferably 0.5 to 2.2 mm, more preferably 0.8 to 2.2 mm.

Originally, the thinner the inner layer 110, the more likely it is that the inner layer peels off. However, since the drainage pipe of the present invention has excellent interlayer stability that suppresses the inner layer peeling, the inner layer peels even if the inner layer 110 is relatively thin. It is possible to effectively obtain interlayer stability that suppresses. From this point of view, as a preferable example of the ratio of the thickness t1 of the inner layer 110, preferably 0.06 to 0.4, more preferably 0.06 to 0.3, still more preferably 0.06 to 0.25. Can be mentioned. Further, from the same viewpoint, as a preferable example of the specific thickness t1 of the inner layer 110, preferably 0.3 to 2.0 mm, more preferably 0.3 to 1.5 mm, still more preferably 0.3 to 1. .2 mm can be mentioned.

The nominal diameter (inner diameter) of the drain pipe 100a is 20 to 200 mm, preferably 40 to 150 mm, more preferably 40 to 100 mm, and further preferably 40 to 60 mm.

The inner layer 110 contains additives such as pigments, stabilizers, stabilizing aids, lubricants, processing aids, antioxidants, and fillers, if necessary, as long as the effects of the present invention are not impaired. It may be.

Outer layer The outer layer 120 is made of a hard polyvinyl chloride resin. This imparts excellent workability to the drainage pipe 100a.

The constituent resin of the outer layer 120 is a polyvinyl chloride-based resin. As a result, connection by electric fusion becomes unnecessary, and good workability can be obtained from the viewpoint of connection. The polyvinyl chloride resin is not particularly limited. Examples thereof include homopolymers and copolymers of vinyl chloride, and post-chlorinated vinyl chloride polymers (chlorinated polyvinyl chloride). These polyvinyl chloride resins may be used alone or in combination of two or more.

Examples of the vinyl chloride copolymer include a copolymer of a vinyl chloride monomer and another comonomer, and a copolymer of a vinyl chloride monomer and a polymer (graft polymer).

In the copolymer of vinyl chloride monomer and other comonomer, other comonomer copolymerizable with vinyl chloride monomer includes, for example, α-olefins such as ethylene, propylene and butylene; vinyl esters such as vinyl propionate. Vinyl ethers such as ethyl vinyl ether and butyl vinyl ether; (meth) acrylates such as methyl (meth) acrylate, butyl (meth) acrylate and hydroxyethyl (meth) acrylate; aromatic vinyls such as styrene and α-methylstyrene; Examples thereof include N-substituted maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide. These comonomer may be used alone or in combination of two or more. The copolymerization ratio of the comomomer is 40% by weight or less.

In the copolymer (graft polymer) of the vinyl chloride monomer and the polymer, examples of the polymer for graft-copolymerizing vinyl chloride include an ethylene-vinyl acetate copolymer and an ethylene-vinyl acetate-carbon monoxide copolymer. Combined, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate-carbon monoxide copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, acrylonitrile-butadiene copolymer, polyurethane, chlorinated polyethylene, Examples thereof include chlorinated polypropylene. The polymer obtained by graft-copolymerizing these vinyl chlorides may be used alone or in combination of two or more. The copolymerization ratio of the polymer graft-copolymerized with vinyl chloride is 40% by weight or less.

Chlorinated polyvinyl chloride is a chlorinated product of the above-mentioned homopolymer and copolymer of vinyl chloride. The chlorine content in the chlorinated polyvinyl chloride is 60% by weight or more, more preferably 64% by weight or more, further preferably 66% by weight or more, still more preferably 67% by weight or more from the viewpoint of heat resistance, and molding. From the viewpoint of ease, 71% by weight or less can be mentioned. The above chlorine content means the chlorine content measured by neutralization titration by an oxygen flask combustion method based on JIS K 7229.

The average degree of polymerization of the polyvinyl chloride resin is 600 to 1400, preferably 800 to 1400. An average degree of polymerization of 600 or more is preferable from the viewpoint of obtaining good mechanical strength, and an average degree of polymerization of 1400 or less is preferable from the viewpoint of moldability. The above-mentioned average degree of polymerization is based on a resin obtained by dissolving a polyvinyl chloride resin in tetrahydrofuran (THF), removing insoluble components by filtration, and then drying and removing THF in the filtrate as a sample. It means the average degree of polymerization measured according to the vinyl chloride resin test method of K-6721.

Among the above-mentioned polyvinyl chloride-based resins, chlorinated polyvinyl chloride having excellent thermal stability is preferable when the drainage pipe 100a is used for drainage of high-temperature drainage at 80 ° C. or higher, preferably 90 ° C. or higher.

Examples of the coefficient of linear expansion of the outer layer 120 include 7.5 × 10 ^-5 / ° C. or lower. Originally, the smaller the linear expansion coefficient of the outer layer 120 (that is, farther from the linear expansion coefficient of the inner layer 110), the lower the interlayer stability tends to be, but the drain pipe of the present invention is excellent in the interlayer stability. Therefore, even if the linear expansion coefficient of the inner layer 110 is relatively small, inter-layer stability can be effectively obtained. From this point of view, a preferable example of the coefficient of linear expansion of the inner layer 110 is preferably 7 × 10 ^-5 / ° C. or less.

The lower limit within the range of the coefficient of linear expansion of the outer layer 120 is not particularly limited, but from the viewpoint of obtaining more preferable interlayer stability, it is preferably 5 × 10 ^-5 / ° C or higher, more preferably 6 × 10 ^-5 / ° C or higher. , More preferably 6.5 × 10 ^-5 / ° C. or higher.

The method for measuring the coefficient of linear expansion is as described above for the coefficient of linear expansion of the inner layer 110.

The thickness t2 of the outer layer 120 may be more than 1 as the ratio (t2 / t1) of the inner layer 110 to the thickness t1. Since the outer layer 120 is made of a hard polyvinyl chloride resin, it does not contain a plasticizer. The drain pipe 100a is provided with more preferable rigidity by being configured so that the thickness of the outer layer 120 made of the hard polyvinyl chloride resin is dominant. As a result, workability closer to that of a rigid polyvinyl chloride resin pipe can be obtained from the viewpoint of gradient management, the number of construction members, man-hours, and the like.

From the viewpoint of making the workability of the drain pipe 100a closer to that of the rigid polyvinyl chloride resin pipe, the t2 / t1 ratio is preferably 2 or more, more preferably 2.5 or more, still more preferably 3 or more, still more preferably 3. .5 or more can be mentioned. The upper limit within the range of the t2 / t1 ratio is not particularly limited, but for example, 7 or less can be mentioned from the viewpoint of ensuring the thickness of the inner layer 110 and better obtaining the interlayer stability by suppressing the inner layer peeling. Can be mentioned.

The specific thickness t2 of the outer layer 120 may differ depending on the nominal diameter of the drain pipe 100a, the thickness of the inner layer 110, and the like, but from the viewpoint of making the workability of the drain pipe 100a closer to that of the hard polyvinyl chloride resin pipe, for example, 2 .5 mm or more, preferably 3 mm or more. The upper limit within the range of the thickness t2 is not particularly limited, but from the viewpoint of the lightness of the water pipe 100a, for example, 4 mm or less can be mentioned.

The outer layer 120 contains additives such as pigments, stabilizers, stabilizing aids, lubricants, processing aids, antioxidants, and fillers, if necessary, as long as the effects of the present invention are not impaired. It may be.

Adhesive layer The adhesive layer 130 is interposed between the inner layer 110 and the outer layer 120 to bond the inner layer 110 and the outer layer 120.

As the constituent resin of the adhesive layer 130, any resin may be used as long as it is a resin capable of adhering the resin constituting the inner layer 110 and the resin constituting the outer layer 120. From the viewpoint of obtaining good interlayer stability against the difference in linear expansion coefficient between the inner layer 110 and the outer layer 120, preferably, a polar group is further introduced into the copolymerized polyester resin composition and the constituent resin of the inner layer 110. Resin is mentioned.

Among these, a resin in which a polar group is further introduced into the constituent resin of the inner layer 110 is preferable from the viewpoint of obtaining better interlayer stability. Examples of the polar group include a hydroxyl group, a carboxyl group, and an amino group. Specifically, a resin in which the constituent resin of the inner layer 110 is the main chain and a polar group is introduced into the main chain can be mentioned. For example, when the inner layer 110 is composed of a polyolefin-based resin, a resin in which a polar group is introduced into the polyolefin main chain can be mentioned. As a result, the main chain portion has an affinity with the inner layer 110 and the polar group portion has an affinity with the outer layer 120, so that the integrity of the inner layer 110 and the outer layer 120 is improved, and further better interlayer stability can be obtained. From the viewpoint of obtaining better interlayer stability, the constituent resin of the adhesive layer 130 may be a mixed resin containing a resin in which a polar group is introduced into the constituent resin of the inner layer 110 and the constituent resin of the inner layer 110. Good. In this case, the constituent resin of the inner layer 110 to be mixed with the constituent resin of the inner layer 110 into which the polar group has been introduced may be in a relationship that can be adhered to each other, and may be the same resin or different resins. You may.

The constituent resin of the adhesive layer 130 preferably has a melting temperature of 95 ° C. or higher. As a result, the interlayer stability of the drainage pipe 100a used for high temperature drainage can be kept better. From the viewpoint of obtaining such an effect better, the melting temperature of the constituent resin of the adhesive layer 130 is more preferably 100 ° C. or higher, more preferably 130 ° C. or higher, still more preferably 150 ° C. or higher, still more preferably 160 ° C. or higher. The above can be mentioned. The upper limit of the melting temperature range is not particularly limited, and examples thereof include 200 ° C. or lower, preferably 180 ° C. or lower. The melting temperature is a temperature obtained by measurement by DSC (differential scanning calorimetry; temperature rise rate 10 ° C./min) based on the C method of JIS K6824.

The thickness t3 of the adhesive layer 130 is, for example, 0.05 to 0.7 mm, preferably 0.1 to 0.6 mm, more preferably 0.3 to 0.6 mm, and more preferably 0.4 to 0.55 mm. Can be mentioned.

Additives such as pigments, stabilizers, stabilizers, lubricants, processing aids, antioxidants, and fillers are added to the adhesive layer 130 as necessary, as long as the effects of the present invention are not impaired. It may be included.

2nd Embodiment FIG. 2 shows a second embodiment of the drainage pipe of the present invention. The drainage pipe 100b shown in FIG. 2 has an inner layer 110b, an outer layer 120, and an adhesive layer 130. That is, the drainage pipe 100b is the same as the drainage pipe 100a of the first embodiment except for the inner layer 110b. Therefore, the constituent materials and thicknesses of the outer layer 120 and the adhesive layer 130 constituting the drainage pipe 100b are the same as those of the outer layer 120 and the adhesive layer 130 in the drainage pipe 100a of the first embodiment. Further, the nominal diameter of the drain pipe 100b is the same as that of the drain pipe 100a.

The inner layer 110b includes a fiber-reinforced resin layer 112b and a fiber-free polyolefin resin skin layer 111b provided inside the fiber-reinforced resin layer 112b.

The fiber reinforced resin layer 112b contains a matrix resin and glass fibers. By including the glass fiber, the heat resistance and rigidity of the drain pipe 100b can be further improved. Examples of the matrix resin include the resin used in the inner layer 110 in the first embodiment. Examples of the skin layer 111b include the resin used in the inner layer 110 in the first embodiment. The fiber-free skin layer 111b constitutes the innermost layer of the drainage pipe 100b, and ensures the smoothness of the inner surface of the drainage pipe 100b.

From the viewpoint of obtaining more preferable integrity between the skin layer 111b and the fiber reinforced resin layer 112b, the matrix resin of the fiber reinforced resin layer 112b and the constituent resin of the skin layer 111b may be in a relationship that can be adhered to each other as long as they can be adhered to each other. It may be the same resin or different resins. Preferably, the matrix resin of the fiber reinforced resin layer 112b and the constituent resin of the skin layer 111b are the same resin.

The thickness of the inner layer 110b is the same as that of the inner layer 110 in the first embodiment. The thickness occupied by the fiber-reinforced resin layer 112b in the inner layer 110b is not particularly limited, but the ratio of the thickness of the fiber-reinforced resin layer 112b to the thickness of the inner layer 110b (thickness of 112b / thickness of 110b) is, for example, 0. .2 to 0.7, preferably 0.5 to 0.7.

Applications The use of the drainage pipe of the present invention is not particularly limited as long as it is used for high-temperature drainage. High-temperature wastewater refers to wastewater having a temperature of T ° C. (however, T ≧ 60). Preferred lower limits within the temperature T ° C range include T ≧ 80, more preferably T ≧ 85, still more preferably T ≧ 87, and even more preferably T ≧ 90. Preferred upper limits within the temperature T ° C range include T ≦ 100, more preferably T ≦ 95, still more preferably T ≦ 93, and even more preferably T ≦ 90.

The meaning of the high temperature drainage temperature T ° C. does not necessarily mean that the drainage pipe always passes the drainage having a temperature T ° C., and means the upper limit of the temperature of the drainage that passes through when using the drainage pipe. .. Preferably, the drainage to be passed is both high temperature drainage and low temperature drainage. That is, it is more preferable that the drainage pipe of the present invention is used in an application in which the drainage pipe of the present invention is repeatedly and alternately exposed to the high temperature drainage and the low temperature drainage. The low-temperature wastewater is not particularly limited as long as it is unheated wastewater, and examples thereof include wastewater having a temperature similar to that of tap water, for example, 1 to 30 ° C.

More specifically, it is more preferable that the drainage pipe of the present invention is used as a drainage pipe for building piping (building drainage pipe). The drainage pipe for building piping is a pipe that constitutes an indoor drainage facility. Drainage pipes for building piping are located near the drainage source, so they are easily exposed to high temperatures, and the temperature of the drainage changes drastically. Since the drainage pipe of the present invention has excellent interlayer stability, the temperature T ° C. of high-temperature drainage is high (for example, T ≧ 80, preferably T ≧ 80) because the drainage source is a kitchen, which is particularly preferable among the construction pipes. T ≧ 85, more preferably T ≧ 87, still more preferably T ≧ 90) An exhaust pipe for kitchen drainage can be mentioned.

Manufacturing Method The drainage pipe of the present invention may be manufactured according to a conventionally known method for manufacturing a multi-layer pipe. Specifically, the drainage pipe of the present invention can be manufactured by multi-layer extrusion molding. More specifically, the extrusion molding machine according to the number of layers constituting the drainage pipe of the present invention and the multi-layer pipe mold having the resin inflow port corresponding to the number of layers are used and kneaded by the extrusion molding machine. The resin composition of each layer is allowed to flow into the multi-layer pipe mold from each resin inflow port, and the resin compositions of each layer are merged in the multi-layer pipe mold to be laminated, and then cooled to obtain the present. The drain pipe of the present invention can be manufactured.

The present invention will be described in more detail with reference to Examples below, but the present invention is not limited thereto.

(1) Manufacture of drainage pipe The drainage pipe shown in Tables 1 and 2 (corresponding to the drainage pipe 100a of the first embodiment) was manufactured by multi-layer extrusion molding. All of the manufactured drainage pipes had a total thickness t of 5 mm, an inner layer thickness t1 of 1 mm, an outer layer thickness t2 of 3.5 mm, an adhesive layer thickness t3 of 0.5 mm, and a nominal diameter (inner diameter) of 50 mm. ..

Details of the constituent resins of each layer shown in Table 1 are as follows.
-HDPE: High-density polyethylene; Asahi Kasei; Suntech; B871
-LDPE: Low density polyethylene; Asahi Kasei; M6555
HPP: Homopolypropylene; manufactured by Prime Polymer Co., Ltd .; E203GP
-Block PP: Block polypropylene; manufactured by Prime Polymer Co., Ltd .; J715M
・ Hard polyvinyl chloride: manufactured by Sekisui Chemical ・ Hard chlorinated polyvinyl chloride: manufactured by Tokuyama Sekisui ・ Adhesive layer constituent resin a: Resin with a functional group introduced with polyolefin as the main chain; manufactured by Mitsubishi Chemical Co., Ltd .; Modic
-Adhesive layer constituent resin b: Ethylene vinyl acetate partially saponified product (resin in which a hydroxyl group is introduced with an ethylene vinyl acetate copolymer as the main chain); manufactured by Tosoh Corporation;
-Adhesive layer constituent resin c: Copolyester composition (copolymerized polyester resin composition); manufactured by Sumitomo Chemical Co., Ltd .; VC-40

(2) Measurement of Material Physical Properties Among the material property values shown in Table 1, the layer thickness, deflection temperature under load, coefficient of longitudinal expansion, and melting temperature were measured by the following methods.

(Layer thickness)
The drainage pipe was cut vertically in the axial direction and measured with a caliper.

(Deflection temperature under load)
The deflection temperature under load at 0.45 MPa was measured according to the B method of JIS K7191.

(Coefficient of linear expansion)
Measured according to ASTMD696.

(Melting temperature)
It was obtained by measurement by DSC (differential scanning calorimetry; temperature rise rate 10 ° C./min) according to the C method of JIS K6824.

(3) Evaluation of interlayer stability The prepared drainage pipe was subjected to a cold water flow test. In the cold / hot water flow test, cold water (temperature 25 ° C.) and hot water (temperature T ° C.) were alternately passed through the drain pipe, and cold water flow and hot water flow were repeated 1000 cycles as one cycle. Then, the end of the pipe was visually inspected and evaluated based on the following criteria. The results obtained are shown in Table 1.

⊚: Neither the elution of the adhesive layer at the end nor the peeling of the inner layer at the end is confirmed. ○: The elution of the adhesive layer is slightly confirmed, but there is no peeling of the inner layer at the end, and high temperature drainage and Repeated drainage of cold water does not pose a problem in practical use Δ: The inner layer peels off slightly at the edges, which is not a big problem under experimental conditions, but there is a concern in practical use ×: There is no elution of the adhesive layer However, the peeling of the inner layer at the end is clearly confirmed. ××: The adhesive layer is eluted, and the peeling of the inner layer at the end is also clearly confirmed. ×××: Liquid progress between layers is confirmed. Be done

As shown in Table 1, although the drainage pipes of Examples 1 to 8 are multi-layer pipes having a hard polyvinyl chloride resin outer layer and a corrosion-resistant inner layer, excellent interlayer stability with respect to high-temperature drainage can be obtained. It was. In particular, the drainage pipes of Examples 5 to 8 have obtained excellent interlayer stability even for higher temperature drainage, and have been found to be particularly suitable for use in kitchen drainage.

100a, 100b ... Drainage pipes 110, 110b ... Inner layer 111b ... Fiber-free layer 112b ... Fiber reinforced resin layer 120 ... Outer layer 130 ... Adhesive layer t ... Total thickness t1 ... Inner layer thickness

Claims (8)

A drainage pipe used for drainage at a temperature of T ° C. (however, T ≧ 60).
It is composed of an inner layer composed of a resin selected from the group consisting of a polyolefin resin, a fluororesin, a polyphenylsulfone resin, and a polyphenylsulfone resin, and a rigid polyvinyl chloride resin provided outside the inner layer. An outer layer to be formed and an adhesive layer provided between the outer layer and the inner layer are included.
A drainage pipe having a weight deflection temperature of the resin constituting the inner layer at 0.45 MPa of T × 0.85 ° C. or higher. The drainage pipe according to claim 1, which is used for drainage at a temperature of T ° C. (where T ≧ 80). The drainage pipe according to claim 2, wherein the resin constituting the inner layer is polypropylene, and the hard polyvinyl chloride-based resin constituting the outer layer is a chlorinated polyvinyl chloride-based resin. The drainage pipe according to any one of claims 1 to 3, wherein the melting temperature of the adhesive layer is 95 ° C. or higher. The drainage pipe according to any one of claims 1 to 4, wherein the ratio of the thickness of the inner layer to the total thickness is 0.06 to 0.44. The drainage pipe according to any one of claims 1 to 5, wherein the inner layer has a thickness of 0.3 to 2.2 mm. The wastewater according to any one of claims 1 to 6, wherein the linear expansion coefficient of the inner layer is 10 × 10 ^-5 / ° C. or higher, and the linear expansion coefficient of the outer layer is 7.5 × 10 ^-5 / ° C. or lower. tube. The drainage pipe according to any one of claims 1 to 7, wherein the inner layer includes a fiber-reinforced resin layer and a fiber-free layer provided inside the fiber-reinforced resin layer.

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