Piping components

Abstract

The present invention provides a cylindrical or tubular piping member, whose inner surface is made of a resin composition containing a polyphenylene ether resin, through which hot water (liquids between 50°C and 100°C) is mainly transported, that suppresses deformation associated with the transport of the liquid, has a high tensile modulus of elasticity between 50°C and 100°C, and further exhibits excellent impact resistance. [Solution] The piping member 1 of the present invention comprises a portion 3 whose inner surface in contact with the liquid is made of a resin composition containing a polyphenylene ether resin, and the coefficient of linear expansion of the resin composition is 8.5 × 10 -5 It is characterized by having a temperature of 7°C or less and a tensile modulus of 1000 to 3000 MPa at 80°C.

Description

[Technical Field]

[0001] The present invention relates to a piping member having a portion of its inner surface, which comes into contact with a liquid, made of a resin composition containing a polyphenylene ether resin. [Background technology]

[0002] Traditionally, when using metal piping to deliver hot water obtained from hot water supply systems to a point of use, scale would adhere to and accumulate on the inner surface, causing the liquid flow rate to become unstable. However, with the development of improved resin technology, resin piping components are now being used.

[0003] For example, Patent Document 1 discloses a resin composition for piping comprising a polystyrene resin (A), a polyphenylene oxide resin (B), and glass fibers (C) having a weight-average fiber length of 1 mm or more and 10 mm or less, wherein the polystyrene resin (A) is 20% by mass or more and 65% by mass or less, the polyphenylene oxide resin (B) is 20% by mass or more and 50% by mass or less, and the glass fibers (C) are 10% by mass or more and 50% by mass or less, as well as a resin piping member formed using this resin composition.

[0004] Furthermore, in the manufacturing of industrial products, when using hot water supplied through pipes from a hot water supply system to perform treatments such as cleaning, sterilization, and disinfection of the workpiece, if metal ions and / or organic matter are present in the hot water that comes into contact with the workpiece at a predetermined concentration or higher, they may be adsorbed onto the workpiece. Therefore, efforts are being made to suppress the inclusion of impurities in the pipes.

[0005] For example, fluororesins that are chemically inert, have gas barrier properties, and have extremely low elution into semiconductor cleaning solutions are used as resins for piping materials for semiconductor cleaning solutions. For example, Patent Document 2 discloses a double-walled fluororesin tube, which consists of two layers of fluororesin, as piping used in semiconductor manufacturing equipment. The inner layer tube is made of a fluororesin with excellent corrosion resistance and chemical resistance (for example, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), or tetrafluoroethylene-ethylene copolymer (ETFE)), and the outer layer tube is made of a fluororesin that can suppress gas permeation (for example, polyvinylidene fluoride (PVDF)). Among the resins used as materials for semiconductor cleaning solution piping, PVDF is used in all of the piping within semiconductor cleaning solution manufacturing equipment and for transporting semiconductor cleaning solutions from semiconductor cleaning solution manufacturing equipment to use points in the semiconductor field, and has become the technical standard for semiconductor cleaning solution piping. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2015-936 [Patent Document 2] Japanese Patent Publication No. 2006-112507 [Overview of the project] [Problems that the invention aims to solve]

[0007] An object of the present invention is to provide a cylindrical or tubular piping member whose inner surface through which hot water (a liquid at 50°C or higher and 100°C or lower) is to be passed is made of a resin composition containing a polyphenylene ether-based resin, in which deformation accompanying the liquid feeding is suppressed, the tensile elastic modulus at 50°C or higher and 100°C or lower is high, and further, the piping member has excellent impact resistance. Another object of the present invention is to provide a piping member capable of suppressing a change in the composition of the liquid accompanying the elution of calcium, zinc, and iron from the inner surface when the above liquid flows.

Means for Solving the Problems

[0008] The present invention is as follows. 1. A piping member comprising a portion whose inner surface in contact with a liquid is made of a resin composition containing a polyphenylene ether-based resin, where the linear expansion coefficient of the resin composition is 8.5×10 -5 / °C or less, and the tensile elastic modulus at 80°C is 1000 to 3000 MPa. 2. The piping member according to item 1 above, wherein the polyphenylene ether-based resin contains an alloy resin of a polyphenylene ether resin and a styrene resin. 3. The piping member according to item 1 above, wherein the resin composition further contains a styrene-based elastomer. 4. The piping member according to item 3 above, wherein the content ratio of the styrene-based elastomer is 3 to 25% by mass based on the resin composition. 5. The piping member according to item 1 above, wherein the elution amounts of calcium, zinc, and iron after the eluate is brought into contact with the inner surface for 6 days under the condition of 80°C are all 30 μg / m 2 or less. 6. The piping member according to item 1 above, wherein the elution amounts of calcium, zinc, and iron after the eluate is brought into contact with the inner surface for 6 days under the condition of 80°C are all 5 μg / m 2 or less. 7. The piping member according to item 1 above, wherein the inner surface has a portion with a surface roughness Rz of 0.5 μm or less. 8. The piping member described in item 1 above, wherein the piping member is a pipe, tube, fitting, flange, or valve. [Effects of the Invention]

[0009] The piping member of the present invention is mainly suitable for transporting hot water (liquids with a temperature of 50°C to 100°C). The inner surface of the piping member is made of a resin composition containing a polyphenylene ether resin, and the coefficient of linear expansion is 8.5 × 10⁻⁶. -5 With a low temperature of less than / °C and excellent impact resistance, deformation associated with the transfer of liquids between 50°C and 100°C is suppressed, and transfer at the desired speed can be expected. Therefore, it is useful in industries that utilize liquids between 50°C and 100°C via piping. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing an example of the cross-sectional structure of the piping member of the present invention. [Figure 2] This is a schematic diagram showing another example of the cross-sectional structure of the piping member of the present invention. [Modes for carrying out the invention]

[0011] The piping member of the present invention is, for example, a pipe, tube, fitting, flange, or valve, and comprises a portion (hereinafter referred to as the "first pipe portion") whose inner surface in contact with liquid is made of a resin composition containing a polyphenylene ether resin, and the coefficient of linear expansion of the resin composition (23°C to 100°C) is 8.5 × 10⁻⁶. -5 A cylindrical or tubular article characterized by having a temperature of 0.7°C or less and a tensile modulus of elasticity of 1000 to 3000 MPa at 80°C.

[0012] The piping member of the present invention may consist only of a first pipe section, or it may include a first pipe section and an exterior section, a reinforcing section, etc., formed on at least a part of its outer surface.

[0013] Figures 1 and 2 are schematic views illustrating the cross-sectional structure of the piping member of the present invention. The piping member 1 in FIG. 1 is a multi-layered piping member including a first pipe portion 3 and an exterior portion 5 formed on at least a part of its outer surface. Also, the piping member 1 in FIG. 2 is a piping member consisting only of the first pipe portion 3. Thus, the piping member of the present invention has a structure in which the liquid flowing through it contacts the inner surface of the first pipe portion 3, that is, the surface where the resin composition containing the polyphenylene ether-based resin is exposed.

[0014] The resin composition according to the present invention contains a polyphenylene ether-based resin, and may further contain other components (described later).

[0015] The polyphenylene ether-based resin according to the present invention is a resin component capable of manufacturing a resin molded product, and preferably consists of a polyphenylene ether resin and another resin. When the polyphenylene ether-based resin consists of a polyphenylene ether resin and another resin, it may be a simple mixture in which both can be easily separated, or a composite in which both are intertwined and not easily separated. In addition, the content ratio of the polyphenylene ether-based resin in the resin composition is preferably 60% or more, and more preferably 70% or more.

[0016] The polyphenylene ether resin is a resin containing at least one kind of structural unit represented by the following general formula (1).

Chemical formula

[0017] In the above general formula (1), R 1 [[ID=3​​​​​If it is an unsubstituted hydrocarbon group, it can be an alkyl group, a phenyl group, etc. In the above general formula (1), R 1 , R 2 , R 3 or R 4 If the atom is a halogen atom, it may be any of Cl, Br, or I. In the above general formula (1), R 1 , R 2 , R 3 or R 4 When is an unsubstituted or substituted hydrocarbon group, the number of carbon atoms in the hydrocarbon group is preferably 1 to 8, more preferably 1 to 4. The unsubstituted hydrocarbon group may be either a saturated hydrocarbon group or an unsaturated hydrocarbon group. Examples of substituted hydrocarbon groups include halogenated hydrocarbon groups, hydrocarbon groups having an amino group, hydrocarbon groups having an alkoxy group, hydrocarbon groups having a cyano group, hydrocarbon groups having a phenoxy group, and hydrocarbon groups having a nitro group. In the above general formula (1), R 1 , R 2 , R 3 or R 4 If the group is an alkoxy group, the number of carbon atoms in the hydrocarbon group constituting the alkoxy is preferably 1 to 8, more preferably 1 to 4.

[0018] Polyphenylene ether resins include poly(2,6-dimethyl-1,4-phenylene) ether, poly(2-methyl-6-ethyl-1,4-phenylene) ether, poly(2,6-diethyl-1,4-phenylene) ether, poly(2,6-ethyl-6-n-propyl-1,4-phenylene) ether, and poly(2,6-di-n-propyl-1,4-phenylene) ether, which consist of only one type of structural unit represented by the above general formula (1). Poly(2-methyl-6-n-butyl-1,4-phenylene) ether, poly(2-ethyl-6-isopropyl-1,4-phenylene) ether, poly(2-methyl-6-chloroethyl-1,4-phenylene) ether, poly(2-methyl-6-hydroxyethyl-1,4-phenylene) ether, poly(2-methyl-6-chloroethyl-1,4-phenylene) ether, poly(2,6-dimethoxy-1,4-phenylene) ether Examples include homopolymers such as poly(2,6-dichloromethyl-1,4-phenylene) ether, poly(2,6-dibromomethyl-1,4-phenylene) ether, poly(2,6-diphenyl-1,4-phenylene) ether, poly(2,6-ditril-1,4-phenylene) ether, poly(26-dichloro-1,4-phenylene) ether, poly(2,6-dibenzyl-1,4-phenylene) ether, and poly(2,5-dimethyl-1,4-phenylene) ether; and copolymers such as 2,6-dimethylphenol / 2,3,6-trimethylphenol copolymer, 2,6-dimethylphenol / 2,3,6-trimethylphenol copolymer, 2,6-diethylphenol / 2,3,6-trimethylphenol copolymer, and 2,6-dipropylphenol / 2,3,6-trimethylphenol copolymer, which consist of multiple types of structural units represented by the above general formula (1).

[0019] The molecular weight of the polyphenylene ether resin is not particularly limited. The number-average molecular weight determined by gel permeation chromatography (GPC) is preferably 10,000 to 100,000, more preferably 30,000 to 60,000.

[0020] Other resins constituting the polyphenylene ether resin according to the present invention include resins containing structural units derived from aromatic vinyl compounds (hereinafter referred to as "styrene resin"), polyamides, polyolefins, polyphenylene sulfide, polyphthalamides, and resins containing structural units derived from unsaturated acid anhydrides. The other resins included may be one or two or more. The content ratio of the polyphenylene ether resin and the other resins is preferably 30-70% by mass and 70-30% by mass, respectively, when the total of both is 100% by mass, and more preferably 40-60% by mass and 60-40% by mass. In the present invention, it is preferable that the polyphenylene ether resin and the other resins constitute an alloy resin.

[0021] In the present invention, the other resin is preferably a styrene resin. The styrene resin can be at least one selected from homopolymers, copolymers, and graft polymers obtained using aromatic vinyl compounds such as styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, and 1,3-dimethylstyrene. For example, polystyrene, rubber-modified polystyrene, ABS resin, styrene-acrylonitrile copolymer, styrene-acrylonitrile-methyl methacrylate copolymer, styrene-butadiene block copolymer, and hydrogenated styrene-butadiene block copolymer can be used.

[0022] When the polyphenylene ether-based resin according to the present invention consists of a polyphenylene ether resin and a styrene resin, it is preferable that the styrene resin is a graft polymer and forms a composite (alloy resin) that intertwines with the polyphenylene ether resin.

[0023] The resin composition according to the present invention may consist solely of a polyphenylene ether resin, or, as described above, may consist of a polyphenylene ether resin and other components.

[0024] Other components include polymer elastomers, antioxidants, ultraviolet absorbers, light stabilizers, flame retardants, lubricants, antistatic agents, antibacterial agents, fillers, and colorants. The resin composition according to the present invention may contain, for example, fibrous fillers in a proportion of 1 to 25% by mass, depending on the application. However, if the filler is present in a proportion of 10% by mass or more, the impact resistance of the first tube portion may be poor. Therefore, the filler may be omitted, or preferably present in a proportion of less than 2% by mass, more preferably less than 1% by mass, and even more preferably less than 0.1% by mass.

[0025] When the resin composition according to the present invention contains a polymer elastomer, the impact resistance of the piping member, including the first pipe section, can be improved, without being limited by its type and structure. The upper limit of the polymer elastomer content is usually 1 to 40% by mass, preferably 3 to 30% by mass, relative to the resin composition.

[0026] The structure of the polymer elastomer may be linear or branched, and may also have a multilayer structure, such as a core-shell type.

[0027] The polymer elastomer is preferably a thermoplastic elastomer, and examples include styrene-based elastomers, olefin-based elastomers, polyester-based elastomers, polyamide-based elastomers, acrylic-based elastomers, urethane-based elastomers, vinyl chloride-based elastomers, and silicone-based elastomers. The polymer elastomer contained in the resin composition may be one type or two or more types.

[0028] In the present invention, the polymer elastomer is preferably a styrene-based elastomer. This styrene-based elastomer contains at least one structural unit represented by the following general formula (2), and is usually a copolymer that further contains structural units derived from other monomers (conjugated dienes, vinyl cyanide compounds, unsaturated acid anhydrides, etc.). [ka] (In the formula, R 11R is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. 12 (where m is an alkyl group with 1 to 20 carbon atoms, and m is an integer from 0 to 5.)

[0029] Styrene-based elastomers are particularly preferred copolymers containing structural units represented by the above general formula (2) and structural units derived from conjugated dienes such as 1,3-butadiene, isoprene, 1,3-pentadiene, and 2,3-dimethyl-1,3-butadiene. Examples of such copolymers include styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), styrene-isobutylene-styrene copolymer (SIBS), styrene-butadiene-butylene-styrene copolymer (SBBS), styrene-ethylene-butylene-styrene copolymer (SEBS), styrene-ethylene-propylene-styrene copolymer (SEPS), and styrene-ethylene-ethylene-propylene-styrene copolymer (SEEPS).

[0030] When the resin composition according to the present invention contains a styrene-based elastomer, its content is preferably 3 to 25% by mass, more preferably 5 to 20% by mass, from the viewpoint of impact resistance of the piping member including the first pipe section.

[0031] The coefficient of linear expansion (23°C to 100°C) of the resin composition according to the present invention is 8.5 × 10⁻⁶ -5 The temperature is below / ℃, preferably 8.0 × 10 -5 / ℃ or lower, more preferably 7.5 × 10 -5 It is below / ℃. This coefficient of linear expansion can be measured by a method in accordance with JIS K 7197. The coefficient of linear expansion of the resin composition constituting the inner surface of the first pipe section that comes into contact with the liquid is 8.5 × 10 -5 Since the temperature is below / ℃, deformation is suppressed when a liquid below 100℃ is brought into contact with the inner surface.

[0032] The tensile modulus (80°C ± 1°C) of the resin composition according to the present invention is 1000 to 3000 MPa, preferably 1500 to 2900 MPa, and more preferably 1800 to 2800 MPa. This tensile modulus can be measured by a method conforming to JIS K 7161. Since the tensile modulus (80°C ± 1°C) of the resin composition constituting the inner surface of the first pipe section that comes into contact with the liquid is 1000 to 3000 MPa, sufficient strength and flexibility at high temperatures are obtained, and pipe meandering due to thermal expansion is suppressed.

[0033] The Charpy impact strength (with notch) of the resin composition according to the present invention is 10 kJ / m², from the viewpoint of resistance to water hammer and external impacts. 2 The above is the standard, preferably 15-40 kJ / m³. 2 This Charpy impact strength can be measured by a method conforming to JIS K 7111.

[0034] In the piping member of the present invention, when an elution test was performed by contacting the inner surface of the first pipe section, which is in contact with the liquid, with an eluent at 80°C for 6 days, the amount of calcium, zinc, and iron eluted was very small. Therefore, it is possible to suppress changes in the liquid composition due to the elution of calcium, zinc, and iron from the inner surface of the first pipe section of the piping member, which will carry liquid at temperatures between 50°C and 100°C. The amount of calcium eluted was 30 μg / m³. 2 The following is preferable: 10 μg / m² 2 More preferably, 5 μg / m² 2 More preferably, 3 μg / m² 2 The following is the result: The amount of zinc eluted is 30 μg / m³. 2 Preferably 10 μg / m² 2 More preferably, 5 μg / m² 2 More preferably, 3 μg / m² 2 The following applies. Furthermore, the amount of iron eluted is preferably 30 μg / m³. 2 More preferably, 10 μg / m² 2 More preferably 5 μg / m² 2 The following is particularly preferred: 3 μg / m² 2 The following applies:

[0035] Furthermore, the eluent used in the elution test is not particularly limited and may be water (distilled water, ultrapure water, etc.), an acidic solution, or an alkaline solution. The specific method of the elution test is as described in the [Examples] below.

[0036] The first pipe section is typically a molded body obtained by subjecting a molten resin composition to injection molding, extrusion molding, press molding, multilayer molding, etc., and contains a very small amount of metal components.

[0037] The piping components of the present invention are mainly applicable to all piping materials that carry hot water (liquids between 50°C and 100°C), but can be pipes, tubes, fittings, flanges, or valves. The line connecting one end of the piping component to the other end may be straight or curved (including wavy or spiral shapes). Furthermore, in the piping member 1 shown in Figures 1 and 2, the cross-sectional shape of the piping member through which the liquid flows (the shape depicted by the outline of the inner surface of the first pipe section) is a perfect circle, but it is not limited to this, and can be an ellipse, a polygon, or the like. Also, the inner surface of the first pipe section may have grooves in the longitudinal direction of the piping member. The average value of the inner diameter (bore diameter) of the cross-sectional shape of the piping member through which the liquid flows is preferably 10 to 500 mm.

[0038] In the present invention, the wall thickness of the first pipe section is preferably 2 mm or more, more preferably 2 to 25 mm, and even more preferably 2.5 to 20 mm, in the case of a single layer consisting only of the first pipe section. In the case of two or more layers, from the viewpoint of elution, it is preferably 1 mm or more, more preferably 1 to 20 mm, and even more preferably 1.5 to 15 mm. Furthermore, the wall thickness from one end to the other end of the piping member may be either uniform or non-uniform.

[0039] In the piping member of the present invention, it is preferable that the inner surface of the first pipe section has a portion with a surface roughness Rz of 0.5 μm or less. From the viewpoint of the fluidity of the liquid inside the piping member, it is particularly preferable that the surface roughness Rz of the entire inner surface is 0.5 μm or less. This surface roughness Rz is even more preferably 0.3 μm or less.

[0040] As described above, the piping member of the present invention may be provided with an outer covering, reinforcing part, etc., on at least a portion of the outer surface of the first pipe section. The constituent material of this outer covering 5 can be selected according to the purpose and may be resin, metal, etc. Furthermore, the outer covering and reinforcing part may consist of multiple layers.

[0041] According to the present invention, the inner surface of the piping member is made of a resin composition containing a polyphenylene ether resin, and the coefficient of linear expansion (23°C to 100°C) is 8.5 × 10 -5 The temperature should be low, below / ℃, and the Charpy impact strength should preferably be 10kJ / m². 2 Therefore, it is suitable for transporting liquids between 50°C and 100°C, and deformation associated with the transport of such liquids is suppressed. Accordingly, it is useful in industries that utilize liquids between 50°C and 100°C via piping. Furthermore, because the piping member of the present invention has a low elution rate of Ca, Zn, and Fe when liquid is brought into contact with its inner surface, it provides a high yield when various liquids are passed through it during product manufacturing (including treatments such as washing, acid washing, alkaline washing, sterilization, and disinfection). For example, it is suitable for situations such as when high-purity water such as ultrapure water, or liquids containing predetermined components with controlled concentrations, are supplied using the piping member of the present invention for semiconductor cleaning. [Examples]

[0042] The present invention will be specifically described below with reference to examples.

[0043] 1. Raw materials for resin compositions for piping components The raw materials for the resin composition used in the manufacture of pipes as piping components are shown below.

[0044] 1-1. Polyphenylene ether resins (1) "Noril 731S-780F" (product name) manufactured by SHPP Japan LLC. It is an alloy resin containing polystyrene. (2) Asahi Kasei Corporation's "Zylon W5002" (product name) This is an alloy resin containing less than 40% by mass of polyphenylene ether and more than 40% by mass of polystyrene. (3) Mitsubishi Gas Chemical Company's "Yupiace AH60" (product name) It is an alloy resin containing polyphenylene ether and polystyrene. (4) Asahi Kasei Corporation's "Zylon 500H" (product name) This is an alloy resin containing less than 40% by mass of polyphenylene ether and more than 50% by mass of polystyrene. (5) Asahi Kasei Corporation's "Zylon AT600" (product name) This alloy resin contains less than 40% by mass of polyphenylene ether and more than 45% by mass of polyamide. (6) Mitsubishi Gas Chemical Company's "Yupiace NX7000" (product name) It is an alloy resin containing polyphenylene ether and polyamide. (7) Mitsubishi Gas Chemical Company's "Yupiace GH20" (product name) This resin composition comprises an alloy resin containing polyphenylene ether and polystyrene, and 20% by mass of glass fibers.

[0045] 1-2. Styrene-based elastomers This is a styrene-butadiene copolymer with a styrene unit content of 40% by mass.

[0046] 2. Manufacturing of resin compositions and pipes for piping components and evaluation thereof. Examples 1-8 and Comparative Examples 1-3 The above raw materials were kneaded and pelletized using a twin-screw extruder in the proportions shown in Table 1 to obtain a resin composition for piping components. When using polyphenylene ether resin alone, the pelletized resin was used as is without kneading. Subsequently, the tensile modulus of elasticity was measured at 23°C±1°C and 80°C±1°C in accordance with JIS K 7161, and the Charpy impact strength (with notch) was measured in accordance with JIS K 7111. These results are also shown in Table 1. Furthermore, pipe 1 (thickness: 3.1 mm, outer diameter: 32 mm, length: 1000 mm) was manufactured using the method described below. Subsequently, the inner surface roughness Rz was measured (average value of 10 measurements) using a roughness analyzer equipped with a diamond stylus (tip radius 2 mm). A test piece taken from pipe 2 (thickness: 6.6 mm, outer diameter: 114 mm, length: 1000 mm) manufactured using the method described below was used as the measurement sample for linear expansion coefficient measurement in accordance with JIS K 7197 (23°C to 100°C), elution tests of Ca, Zn, and Fe using 80°C hot water (described later), and actual flow tests using 90°C hot water (described later).

[0047] <Pipe Manufacturing Method> Pellets of polyphenylene ether resin, or pellets formed by kneading polyphenylene ether resin and styrene elastomer as described in the examples, were used to form pipe 1, made of a polyphenylene ether resin composition with a wall thickness of 3.1 mm and an outer diameter of 32 mm, and pipe 2, made of a polyphenylene ether resin composition with a wall thickness of 6.6 mm and an outer diameter of 114 mm, using a single-screw extruder at a cylinder temperature of 250°C.

[0048] <80°C Hot Water Elution Test> In accordance with the UC standard "Method for testing the elution of piping materials for ultrapure water," a sample pipe was prepared by fusing a cap to one end of the above-mentioned pipe 1. The inner surface of this sample pipe was washed for 1 hour while ultrapure water was flowed through it at a rate of 1 L / min. Then, with the inside of the pipe filled with ultrapure water, the end face of the pipe was covered with a pre-cleaned PTFE sheet, and the cap was fitted to seal it. Next, the sample pipe was left to stand in a constant temperature incubator set to 80°C ± 2°C for 6 days to allow elution. Quantitative analysis of calcium, zinc, and iron in the eluate was performed using an Agilent Technologies ICP-mass spectrometer (MS) "Agirent 8900" (model name).

[0049] <90°C hydrothermal flow test> A straight pipe with a diameter of 25A (outer diameter 32mm, wall thickness 3.1mm) and a length of 4000mm was placed on a 4500mm H-beam, both ends were fixed with fixing members, and the pipe was fixed at a point one-third of its length from the end with a fixing jig. After filling the pipe with water, 90°C hot water was passed through the pipe using a mold temperature control machine. One hour later, five panelists visually observed the condition of the pipe and visually determined whether the pipe had undergone meandering deformation due to thermal expansion. Gentle bending due to pipe deflection was not considered meandering deformation, while a wavy bending state was considered meandering deformation. ○: Only three people were found to have observed meandering deformation of the pipes. ×: Four or more people observed meandering deformation of the pipe.

[0050] For reference, commercially available polyvinylidene fluoride pipes were subjected to the same analysis or evaluation as described above, and the results are shown in Table 1.

[0051] [Table 1]

[0052] The following is clear from Table 1: Examples 1-8 have a coefficient of linear expansion of 8.5 × 10⁻⁶ of the resin composition at 23°C to 100°C. -5 The temperature was below / ℃, and the tensile modulus at 80℃ was 1000 to 3000 MPa. As a result, even when supplying liquids at temperatures between 50℃ and 100℃ through pipes, tubes, fittings, flanges, or valves obtained by molding the resin compositions of Examples 1 to 8, deformation of the piping components is suppressed, resulting in excellent durability. Furthermore, when the inner surface of the pipe is exposed to 80℃ hot water for 6 days, the elution amounts of Ca, Zn, and Fe were 30 μg / m³. 2Furthermore, the amount of these elements leached out was lower than that of conventional polyvinylidene fluoride products, and it could be used in the same way as conventional polyvinylidene fluoride products for applications in liquids from -20°C to 120°C. For example, when manufacturing semiconductor-related products, electronic material-related products, liquid crystal-related products, pharmaceutical-related products, etc., yield reduction due to Ca, Zn, or Fe is suppressed, especially in the hot water temperature range. In addition, when a styrene elastomer was added to the polyphenylene ether resin, the Charpy impact strength was improved compared to when it was not included, resulting in improved impact resistance. [Industrial applicability]

[0053] The piping member of the present invention exhibits excellent durability, as deformation of the piping member is suppressed when various liquids at temperatures between 50°C and 100°C are passed through it during product manufacturing or heat treatment. Taking advantage of these properties, it is suitable as a piping member in equipment for manufacturing semiconductor-related products, electronic material-related products, liquid crystal-related products, pharmaceutical-related products, etc., or as a piping member for liquids supplied to such equipment. [Explanation of Symbols]

[0054] 1: Piping components 3: First Section 5:Exterior part

Claims

1. A piping member comprising a portion whose inner surface in contact with a liquid is made of a resin composition containing a polyphenylene ether resin, The coefficient of linear expansion of the resin composition is 8.5 × 10 －５ A piping member characterized by having a temperature of 0°C or less and a tensile modulus of elasticity of 1000 to 3000 MPa at 80°C.

2. The piping member according to claim 1, wherein the polyphenylene ether resin includes an alloy resin of a polyphenylene ether resin and a styrene resin.

3. The piping member according to claim 1, wherein the resin composition further comprises a styrene-based elastomer.

4. The piping member according to claim 3, wherein the content of the styrene-based elastomer is 3 to 25% by mass relative to the resin composition.

5. Under conditions of 80°C, after contacting the eluent with the inner surface for 6 days, the elution amounts of calcium, zinc, and iron were all 30 μg / m². ２ The piping member according to claim 1, which is as follows:

6. Under conditions of 80°C, after contacting the eluent with the inner surface for 6 days, the elution amounts of calcium, zinc, and iron were all 5 μg / m². ２ The piping member according to claim 1, which is as follows:

7. The piping member according to claim 1, wherein the inner surface has a portion having a surface roughness Rz of 0.5 μm or less.

8. The piping member according to claim 1, wherein the piping member is a pipe, tube, fitting, flange, or valve.

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