Polyarylene sulfide resin pipe and manufacturing method

Abstract

Provided are: a polyarylene sulfide (PAS) resin pipe having all of processability, hot water resistance, and water pressure resistance; and a manufacturing method therefor. More specifically, provided are: a PAS resin pipe having a non-bent part and a bent part and obtained by bending a single-layer tubular molded article composed of a PAS resin composition at a temperature that is equal to or higher than the glass transition point of a PAS resin, wherein the tensile elongation at break of the PAS resin composition is at least 70%, and the minimum outer diameter of the bent part is at least 70% of the average outer diameter of the non-bent part; a composite; and manufacturing methods therefor.

Description

Polyarylene sulfide resin pipe and manufacturing method

[0001] The present invention relates to a pipe made of a polyarylene sulfide resin composition and a method for producing the same.

[0002] In recent years, due to copper supply shortages and price fluctuations, new materials are being sought for plumbing components in hot and cold water supply systems. Furthermore, conventional copper pipes have issues such as internal corrosion, corrosion of the exterior of the pipe caused by insulation, and noise caused by water impact. Due to these factors, there has been a demand for resin-based plumbing components that are easy to process and highly corrosion-resistant.

[0003] Because hot water supply equipment piping must be both hot water resistant and water pressure resistant, polyarylene sulfide (PAS) resins, such as polyphenylene sulfide (PPS) resin, which have excellent mechanical strength and hot water resistance, have been proposed. For example, Patent Document 1 discloses a piping component made of a polyphenylene sulfide resin composition obtained by blending 10 to 100 parts by weight of a fibrous filler and 4 to 15 parts by weight of an olefin-based elastomer resin with 100 parts by weight of polyphenylene sulfide resin.

[0004] Japanese Patent Application Laid-Open No. 2017-155065

[0005] In this way, in order to improve the processability of PAS resin, designs are sometimes made to impart toughness by blending elastomers, but on the other hand, there is the problem that the resin becomes prone to deformation during use and has poor water pressure resistance.

[0006] Therefore, an object of the present invention is to provide a PAS resin pipe that is easy to process, has high hot water resistance, and is water pressure resistant, and a method for producing the same.

[0007] As a result of various investigations, the inventors have completed the present invention by adjusting the shape of the tubular molded article and the compounding ratio of the PAS resin.

[0008] That is, the present invention encompasses the following aspects. [1] A resin pipe having a non-bent portion and a bent portion, obtained by bending a single-layer tubular molded product made of a PAS resin composition at a temperature equal to or higher than the glass transition point of the PAS resin, wherein the PAS resin composition has a tensile breaking elongation of 70% or more, and the minimum outer diameter of the bent portion is 70% or more of the average outer diameter of the non-bent portion. [2] The PAS resin pipe according to [1] above, wherein the difference between the maximum outer diameter and the minimum outer diameter of the non-bent portion of the tubular molded product is 0.3 mm or less. [3] The PAS resin pipe according to [1] or [2] above, wherein the arithmetic mean height Sa of the inner wall of the bent portion is 60 μm or less and the maximum height Sz is 350 μm or less. [4] The PAS resin pipe according to [1] to [3] above, wherein the content of PAS resin is 75 parts by mass or more per 100 parts by mass of the PAS resin composition. [5] The PAS resin pipe according to any one of [1] to [4] above, wherein the PAS resin composition has a tensile modulus of 1.0 GPa or more. [6] The PAS resin pipe according to any one of [1] to [5] above, wherein the PAS resin composition has an MFR of 10 g / 10 min or less. (Note that the MFR is a value measured at a temperature of 315°C and a load of 2.16 kg.) [7] The PAS resin pipe according to any one of [1] to [6] above, wherein the PAS resin composition has a temperature-decreasing crystallization temperature of 230°C or less. (Note that the temperature-decreasing crystallization temperature is the peak-top value of the exothermic peak observed when the PAS resin composition is melted at 350°C for 3 minutes using a differential scanning calorimeter and then cooled to 40°C at 20°C / min.) [8] The PAS resin pipe according to any one of [1] to [7] above, wherein the PAS resin composition further contains a thermoplastic elastomer. [9] The PAS resin pipe according to any one of [1] to [8] above, having a water pressure resistance of 2.0 MPa or more.

[10] A composite obtained by combining the PAS resin pipe according to any one of [1] to [9] above with a fitting.

[11] A method for producing a resin pipe, comprising the steps of extrusion molding a PAS resin composition to obtain a single-layer tubular molded product, and bending the tubular molded product at a temperature equal to or higher than the glass transition point of the PAS resin to form a bent portion, wherein the difference between the maximum outer diameter and the minimum outer diameter of a non-bent portion of the tubular molded product is 0.3 mm or less, and the content of the PAS resin per 100 parts by mass of the PAS resin composition is 75 parts by mass or more.

[12] A method for producing a PAS resin pipe according to

[11] above, wherein the minimum outer diameter of the bent portion is 70% or more of the average outer diameter of the non-bent portion.

[13] A method for producing a PAS resin pipe according to

[11] or

[12] above, wherein the arithmetic mean height Sa of the inner wall of the bent portion is 60 μm or less and the maximum height Sz is 350 μm or less.

[14] A method for producing a PAS resin pipe according to

[11] to

[13] above, wherein the PAS resin composition has a tensile breaking elongation of 70% or more.

[15] A method for producing a PAS resin pipe according to

[11] to

[14] above, wherein the PAS resin composition has a tensile modulus of elasticity of 1.0 GPa or more.

[16] A method for producing a PAS resin pipe according to

[11] to

[15] above, wherein the PAS resin composition has an MFR of 10 g / 10 min or less. (However, MFR is a value measured at a temperature of 315°C and a load of 2.16 kg.)

[17] A method for producing a PAS resin pipe according to any one of

[11] to

[16] above, wherein the PAS resin composition has a crystallization temperature under temperature decrease of 230°C or lower. (However, the crystallization temperature under temperature decrease is the peak-top value of the exothermic peak observed when the PAS resin composition is melted at 350°C for 3 minutes using a differential scanning calorimeter and then cooled to 40°C at 20°C / min.)

[18] A method for producing a PAS resin pipe according to any one of

[11] to

[17] above, wherein the PAS resin composition further contains a thermoplastic elastomer.

[19] A PAS resin pipe according to any one of

[11] to

[18] above, wherein the water pressure resistance is 2.0 MPa or higher.

[20] A method for producing a composite, comprising a step of joining the PAS resin pipe produced by any one of

[11] to

[19] above to a fitting.

[0009] According to the present invention, it is possible to provide a PAS resin pipe that is easy to process, has high hot water resistance, and has high water pressure resistance, and a method for producing the same.

[0010] Hereinafter, one embodiment of the present invention will be described in detail, but the scope of the present invention is not limited to the embodiment described here, and various modifications can be made without departing from the spirit of the present invention. Furthermore, when multiple upper and lower limit values ​​are specified for a specific parameter, any upper and lower limit values ​​can be combined to form a suitable numerical range.

[0011] <PAS Resin Pipe, Manufacturing Method of PAS Resin Pipe> The PAS resin pipe of this embodiment is a resin pipe having a non-bent portion and a bent portion, obtained by bending a single-layer tubular molded article made of a PAS resin composition at or above the glass transition temperature of the PAS resin. The PAS resin composition has a tensile breaking elongation of 70% or more, and the minimum outer diameter of the bent portion is 70% or more of the average outer diameter of the non-bent portion. The manufacturing method of the PAS resin pipe of this embodiment includes the steps of extruding a PAS resin composition to obtain a single-layer tubular molded article and bending the tubular molded article at or above the glass transition temperature of the PAS resin to form a bent portion. The manufacturing method is characterized in that the difference between the maximum outer diameter and the minimum outer diameter of the non-bent portion of the tubular molded article is 0.3 mm or less, and the PAS resin content is 75 parts by mass or more per 100 parts by mass of the PAS resin composition. This is described in detail below.

[0012] <PAS Resin Composition> The PAS resin composition applicable to this embodiment contains a PAS resin as an essential component.

[0013] The PAS resin has a resin structure having a repeating unit in which an aromatic ring and a sulfur atom are bonded, and specifically, a PAS resin represented by the following general formula (1):

[0014] (In the formula, R １ and R ２ each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a nitro group, an amino group, a phenyl group, a methoxy group, or an ethoxy group, and, if necessary, a structural portion represented by the following general formula (2):

[0015] The trifunctional structural moiety represented by formula (2) is preferably present in an amount of 0.001 to 3 mol %, particularly preferably 0.01 to 1 mol %, based on the total number of moles of the trifunctional structural moiety and other structural moieties.

[0016] Here, the structural moiety represented by the general formula (1) is particularly R １ and R ２is preferably a hydrogen atom from the viewpoint of the mechanical strength of the PAS resin, and in that case, examples include those bonded at the para position represented by the following formula (3) and those bonded at the meta position represented by the following formula (4).

[0017] Among these, a structure in which the bond between the sulfur atom and the aromatic ring in the repeating unit is at the para position represented by the general formula (3) is particularly preferred in terms of the heat resistance of the PAS resin.

[0018] The PAS resin may contain not only the structural moieties represented by the general formula (1) or (2) but also the structural moieties represented by the following structural formulae (5) to (8):

[0019] The structural moieties represented by the general formula (1) and the general formula (2) may be contained in an amount of 30 mol % or less of the total of the structural moieties represented by the general formula (1) and the general formula (2). In particular, in the present disclosure, it is preferable that the structural moieties represented by the general formulas (5) to (8) be 10 mol % or less from the viewpoint of the heat resistance and mechanical strength of the PAS. When the structural moieties represented by the general formulas (5) to (8) are contained in the PAS resin, the bonding mode thereof may be either a random copolymer or a block copolymer.

[0020] The PAS resin may also have naphthyl sulfide bonds or the like in its molecular structure, but the amount of such bonds is preferably 3 mol % or less, and particularly preferably 1 mol % or less, relative to the total number of moles including other structural moieties.

[0021] The physical properties of the PAS resin are not particularly limited as long as they do not impair the effects of the present invention, but are as follows.

[0022] (Melt Viscosity) The melt viscosity (V6) of the PAS resin used in this embodiment is preferably in the range of 50 to 200 Pa s, more preferably 70 to 150 Pa s, as measured at 300°C, in order to achieve a good balance between the discharge speed and the take-up stability during extrusion molding. The melt viscosity (V6) of the PAS resin is measured using a flow tester, CFT-500D, manufactured by Shimadzu Corporation, at 300°C and a load of 1.96 x 10 ６The melt viscosity is measured after holding the sample at a temperature of 10 Pa and L / D=10 (mm) / 1 (mm) for 6 minutes.

[0023] (Weight-average molecular weight) From the viewpoint of molding stability during extrusion molding, the weight-average molecular weight (Mw) of the PAS resin used in this embodiment is 30,000 to 100,000, and more preferably 35,000 to 60,000. The weight-average molecular weight of the PAS resin of the present invention is a weight-average molecular weight measured using gel permeation chromatography under the following measurement conditions. Six types of monodisperse polystyrene are used for calibration. Apparatus: Ultra-high temperature polymer molecular weight distribution measurement apparatus ("SSC-7000" manufactured by Senshu Scientific Co., Ltd.) Column: UT-805L (manufactured by Showa Denko K.K.) Column temperature: 210°C Solvent: 1-chloronaphthalene Measurement method: UV detector (360 nm)

[0024] (Non-Newtonian Index) The non-Newtonian index of the PAS resin used in this embodiment is not particularly limited, but is preferably in the range of 0.95 to 1.50. Within this range, the PAS resin composition has excellent mechanical strength. However, in this disclosure, the non-Newtonian index (N value) is a value calculated using the following formula after measuring the shear rate (SR) and shear stress (SS) using a capillograph under conditions of a melting point of +20°C and a ratio of the orifice length (L) to the orifice diameter (D), L / D = 40. The closer the non-Newtonian index (N value) is to 1, the more linear the structure is, and the higher the non-Newtonian index (N value), the more branched the structure is.

[0025] [where SR is the shear rate (sec －１ ), SS is the shear stress (dyne / cm ２ ), and K denotes a constant.

[0026] (Production Method) The method for producing the PAS resin is not particularly limited, but examples thereof include (Production Method 1) a method in which a dihalogenoaromatic compound is polymerized in the presence of sulfur and sodium carbonate, and if necessary, a polyhalogenoaromatic compound or other copolymerization component is added; (Production Method 2) a method in which a dihalogenoaromatic compound is polymerized in a polar solvent in the presence of a sulfidizing agent or the like, and if necessary, a polyhalogenoaromatic compound or other copolymerization component is added; (Production Method 3) a method in which p-chlorothiophenol is added, and if necessary, other copolymerization components are added, and then self-condensed; and (Production Method 4) a method in which a diiodoaromatic compound and elemental sulfur are melt-polymerized under reduced pressure in the presence of a polymerization inhibitor that may have a functional group such as a carboxyl group or an amino group. Of these methods, (Production Method 2) is preferred because it is versatile. During the reaction, an alkali metal salt of a carboxylic acid or sulfonic acid or an alkali hydroxide may be added to adjust the degree of polymerization. Among the above-mentioned (Production Method 2) methods, there is a method for producing a PAS resin by introducing a water-containing sulfidizing agent into a mixture containing a heated organic polar solvent and a dihalogeno aromatic compound at a rate at which water can be removed from the reaction mixture, and then adding the dihalogeno aromatic compound and the sulfidizing agent, and optionally a polyhalogeno aromatic compound, in the organic polar solvent to react with each other, and controlling the amount of water in the reaction system to be in the range of 0.02 to 0.5 moles per mole of the organic polar solvent (see JP-A-07-228699). Particularly preferred is a copolymer obtained by a method in which a dihalogenoaromatic compound and, if necessary, a polyhalogenoaromatic compound or other copolymerization component are added in the presence of an alkali metal sulfide and an aprotic polar organic solvent, and an alkali metal hydrosulfide and an organic acid alkali metal salt are reacted while controlling the amount of organic acid alkali metal salt in the range of 0.01 to 0.9 mol per mol of the sulfur source and the amount of water in the reaction system to 0.02 mol or less per mol of the aprotic polar organic solvent (see WO 2010 / 058713 pamphlet).Specific examples of the dihalogeno aromatic compound include p-dihalobenzene, m-dihalobenzene, o-dihalobenzene, 2,5-dihalotoluene, 1,4-dihalonaphthalene, 1-methoxy-2,5-dihalobenzene, 4,4'-dihalobiphenyl, 3,5-dihalobenzoic acid, 2,4-dihalobenzoic acid, 2,5-dihalonitrobenzene, 2,4-dihalonitrobenzene, 2,4-dihaloanisole, p,p'-dihalodiphenyl ether, 4,4'-dihalobenzophenone ... Examples of the polyhalogenoaromatic compounds include 1,2,3-trihalobenzene, 1,2,4-trihalobenzene, 1,3,5-trihalobenzene, 1,2,3,5-tetrahalobenzene, 1,2,4,5-tetrahalobenzene, 1,4,6-trihalonaphthalene, etc. The halogen atoms contained in the above compounds are preferably chlorine atoms or bromine atoms.

[0027] The method for post-treating the reaction mixture containing the PAS resin obtained by the polymerization step is not particularly limited, and examples thereof include: (post-treatment 1) after the completion of the polymerization reaction, first, distilling off the solvent from the reaction mixture either as is or after adding an acid or a base under reduced pressure or normal pressure, and then washing the solid obtained after the solvent distillation once or twice or more times with a solvent such as water, the reaction solvent (or an organic solvent having a similar solubility to the low-molecular-weight polymer), acetone, methyl ethyl ketone, or alcohols, followed by neutralization, washing with water, filtering, and drying; or (post-treatment 2) after the completion of the polymerization reaction, adding a solvent such as water, acetone, methyl ethyl ketone, alcohols, ethers, halogenated hydrocarbons, aromatic hydrocarbons, or aliphatic hydrocarbons (soluble in the polymerization solvent used and poorly soluble in at least the PAS) to the reaction mixture. Examples of such methods include: (1) adding a solvent (which is a solvent for polymerization) as a precipitant to the reaction mixture, allowing solid products such as PAS and inorganic salts to precipitate, followed by filtration, washing, and drying; (2) adding a reaction solvent (or an organic solvent having equivalent solubility to the low-molecular-weight polymer) to the reaction mixture after the polymerization reaction is complete, stirring the mixture, filtering to remove the low-molecular-weight polymer, washing once or twice or more times with a solvent such as water, acetone, methyl ethyl ketone, or an alcohol, followed by neutralization, washing with water, filtering, and drying; (3) adding water to the reaction mixture after the polymerization reaction is complete, washing with water, filtering, and optionally adding an acid during the water washing step to perform an acid treatment, followed by drying; and (4) filtering the reaction mixture after the polymerization reaction is complete, and optionally washing once or twice or more times with the reaction solvent, followed by further washing with water, filtering, and drying. Among these methods, (4) is preferred because it enables the production of a PAS resin having carboxyl groups at the molecular terminals of the PAS resin.

[0028] In the post-treatment methods exemplified above as (Post-treatment 1) to (Post-treatment 5), the PAS resin may be dried in a vacuum, in air, or in an inert gas atmosphere such as nitrogen.

[0029] In the PAS resin composition used in this embodiment, the blending amount of the PAS resin is preferably 30 to 80 parts by mass, more preferably 40 to 70 parts by mass, per 100 parts by mass of the resin composition. In this range, the resin composition is preferred because it has excellent heat resistance and mechanical strength.

[0030] The PAS resin used in this embodiment can be a PAS resin newly polymerized using the above method, or a recycled PAS resin. For example, PAS resin recovered from a PAS resin composition or a PAS resin molded product can be used. Specifically, a PAS resin obtained by heating a PAS resin composition or a PAS resin molded product in an organic polar solvent to dissolve the PAS contained therein and then performing the above-described post-treatment on the resulting solution can be used. Mechanically pulverized PAS resin compositions or PAS resin molded products can also be used as PAS resins. Specifically, sprues or runners generated during the production of molded products, recovered non-standard molded products, or pulverized molded products once used as products can be used. In this case, pulverized PAS resin compositions or PAS resin molded products containing components other than PAS resin can also be used. However, from the perspective of mechanical strength, the PAS resin content is preferably 90 parts by mass or more, more preferably 95 parts by mass or more, and even more preferably 98 parts by mass or more.

[0031] The PAS resin composition applicable to this embodiment can contain an elastomer as an optional component, if necessary. By including the elastomer, the molding stability of the resin composition and the roundness of the bent portion during bending can be further improved. From the same viewpoint, it is preferable to use a thermoplastic elastomer as the elastomer. The thermoplastic elastomer is not particularly limited as long as it does not impair the effects of the present invention. Examples of the thermoplastic elastomer include polyolefin elastomers, fluorine-based elastomers, and silicone-based elastomers.

[0032] Examples of the polyolefin elastomer include a homopolymer of an α-olefin, a copolymer of two or more α-olefins, and a copolymer of one or more α-olefins with a vinyl polymerizable compound having a functional group. In this case, examples of the α-olefin include α-olefins having 2 or more to 8 carbon atoms, such as ethylene, propylene, and 1-butene. Examples of the functional group include a carboxy group, an acid anhydride group (—C(═O)OC(═O)—), an epoxy group, an amino group, a hydroxyl group, a mercapto group, an isocyanate group, and an oxazoline group. Examples of the vinyl polymerizable compound having a functional group include one or more of vinyl acetate; α,β-unsaturated carboxylic acids such as (meth)acrylic acid; alkyl esters of α,β-unsaturated carboxylic acids such as methyl acrylate, ethyl acrylate, and butyl acrylate; metal salts of α,β-unsaturated carboxylic acids such as ionomers (metals include alkali metals such as sodium, alkaline earth metals such as calcium, and zinc); glycidyl esters of α,β-unsaturated carboxylic acids such as glycidyl methacrylate; α,β-unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; and derivatives of the above α,β-unsaturated dicarboxylic acids (monoesters, diesters, and acid anhydrides). The above-mentioned thermoplastic elastomers may be used alone or in combination of two or more. Among these, ethylene-propylene copolymers and ethylene-butene copolymers having at least one functional group selected from the group consisting of an epoxy group, a carboxyl group, and a group represented by the formula: R(CO)O(CO)- or R(CO)O- (wherein R represents an alkyl group having 1 to 8 carbon atoms) are preferred from the viewpoint of improving toughness and impact resistance. In the present embodiment, the elastomer is an optional component, but the proportion when blended is not particularly limited. For example, the amount is preferably 5 to 50 parts by mass, more preferably 8 to 30 parts by mass, and even more preferably 10 to 25 parts by mass, relative to 100 parts by mass of the PAS resin.

[0033] The PAS resin composition applicable to this embodiment may contain a silane coupling agent as an optional component, if necessary. The silane coupling agent is not particularly limited as long as it does not impair the effects of the present invention, but preferred examples include silane coupling agents having a functional group that reacts with a carboxy group, such as an epoxy group, an isocyanato group, an amino group, or a hydroxyl group. Examples of such silane coupling agents include epoxy group-containing alkoxysilane compounds such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; isocyanato group-containing alkoxysilane compounds such as γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-isocyanatopropylmethyldimethoxysilane, γ-isocyanatopropylmethyldiethoxysilane, γ-isocyanatopropylethyldimethoxysilane, γ-isocyanatopropylethyldiethoxysilane, and γ-isocyanatopropyltrichlorosilane; amino group-containing alkoxysilane compounds such as γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane; and hydroxyl group-containing alkoxysilane compounds such as γ-hydroxypropyltrimethoxysilane and γ-hydroxypropyltriethoxysilane. Although a silane coupling agent is not an essential component in the present invention, when it is used, its amount is not particularly limited as long as it does not impair the effects of the present invention, but is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the PAS resin. Within such a range, the resin composition has good moldability, particularly mold releasability, and the mechanical strength of the molded article is improved, which is preferable.

[0034] The PAS resin composition applicable to this embodiment may optionally contain a filler. Known and commonly used fillers can be used as long as they do not impair the effects of the present invention. Examples of such fillers include inorganic fillers of various shapes, such as fibrous fillers and non-fibrous fillers such as granular and plate-shaped fillers. Specifically, fibrous fillers such as glass fiber, carbon fiber, silane glass fiber, ceramic fiber, aramid fiber, metal fiber, potassium titanate, silicon carbide, calcium silicate, and wollastonite, as well as natural fibers, can be used. Non-fibrous fillers such as glass beads, glass flakes, barium sulfate, clay, pyrophyllite, bentonite, sericite, mica, talc, attapulgite, ferrite, calcium silicate, calcium carbonate, glass beads, zeolite, milled fiber, and calcium sulfate can also be used. Specific examples of surface treatment agents for treating the surface of inorganic fillers include epoxy compounds, isocyanate compounds, silane compounds, titanate compounds, borane treatment, ceramic coating, etc. Among these, epoxy compounds or silane compounds are preferred. The amount of filler to be added is, for example, more preferably 40 parts by mass or less, even more preferably 30 parts by mass or less, and particularly preferably 25 parts by mass or less, per 100 parts by mass of PAS resin, from the viewpoint of obtaining excellent processability of the resin composition and smoothness of the surface of the molded article. If the amount added exceeds 40 parts by mass, the toughness of the resin composition may be poor.

[0035] In addition to the above components, the PAS resin composition applicable to this embodiment may further contain, as appropriate depending on the application, synthetic resins (hereinafter simply referred to as synthetic resins), such as polyester resin, polyamide resin, polyimide resin, polyetherimide resin, polycarbonate resin, polyphenylene ether resin, polysulfone resin, polyethersulfone resin, polyetheretherketone resin, polyetherketone resin, polyarylate resin, polyethylene resin, polypropylene resin, polyethylenetetrafluoroethylene resin, polyethylenedifluoroethylene resin, polystyrene resin, ABS resin, phenolic resin, urethane resin, and liquid crystal polymer, as optional components. While the synthetic resin is not an essential component in this embodiment, if it is included, its proportion is not particularly limited as long as it does not impair the effects of the present invention. Furthermore, the proportion of the synthetic resin included in the resin composition according to the present invention varies depending on the respective purposes and cannot be generally defined. For example, the proportion of the synthetic resin included in the resin composition according to the present invention is 5 to 15 parts by mass per 100 parts by mass of the PAS resin.

[0036] Furthermore, the PAS resin composition applicable to this embodiment may contain other known and commonly used additives as optional components as needed, as long as they do not impair the effects of the present invention, such as colorants, antistatic agents, antioxidants, heat stabilizers, UV stabilizers, UV absorbers, foaming agents, flame retardants, flame retardant assistants, rust inhibitors, and mold release agents (metal salts or esters of fatty acids having 18 to 30 carbon atoms, including stearic acid or montanic acid, polyolefin waxes such as polyethylene, etc.). For example, the amount of the additives is preferably 0.01 to 500 parts by mass, more preferably 0.1 to 250 parts by mass, and even more preferably 0.5 to 100 parts by mass, per 100 parts by mass of the PAS resin.

[0037] The physical properties of the resin composition applicable to this embodiment are not particularly limited as long as they do not impair the effects of the present invention, and are as follows.

[0038] (Tensile Breaking Elongation) The tensile breaking elongation of the resin composition applicable to this embodiment is preferably 70% or more, more preferably 90% or more. Within this range, the pipe exhibits excellent bending workability and joint workability. The tensile breaking elongation in this disclosure is a value measured by the method described in the Examples. The tensile breaking elongation of the resin composition may be adjusted by a known method, for example, by adjusting the melt viscosity or molecular weight of the resin.

[0039] (Tensile Modulus) The tensile modulus of the resin composition applicable to this embodiment is preferably 1.0 GPa or more, more preferably 1.5 GPa or more. Within this range, the pipe exhibits excellent water pressure resistance. The tensile modulus in this disclosure is a value measured by the method described in the Examples. The tensile breaking elongation of the resin composition may be adjusted by a known method, for example, by adjusting the melt viscosity or molecular weight of the resin.

[0040] (Melt Flow Rate) The melt flow rate (MFR) of the resin composition applicable to this embodiment is preferably 10 g / 10 min or less, more preferably 5 g / 10 min or less. Within this range, the balance between discharge speed and take-up stability is good for pipe extrusion molding. The MFR of the resin composition may be adjusted by a known method, for example, by adjusting the melt viscosity, molecular weight, structure, etc. of the resin. The MFR in this disclosure is a value measured by the method described in the examples.

[0041] (Cooling-Down Crystallization Temperature) The cooling-down crystallization temperature of the resin composition applicable to this embodiment is preferably 230°C or less. When it is in this range, the solidification time of the resin during molding is delayed, making it easier to control the diameter and thickness of the pipe. Note that the cooling-down crystallization temperature in this disclosure is the peak top temperature of the exothermic peak observed when the resin composition is heated to 350°C for 3 minutes to melt it, and then cooled to 40°C at 20°C / min using a differential scanning calorimeter.

[0042] The method for producing a PAS resin composition applicable to this embodiment is not particularly limited, but examples thereof include a method in which a PAS resin and, if necessary, optional components are blended and melt-kneaded, more specifically, a method in which the mixture is uniformly dry-mixed in a tumbler or Henschel mixer, if necessary, and then introduced into a twin-screw extruder for melt-kneading.

[0043] The melt kneading can be carried out by heating the resin to a temperature range in which the resin temperature is equal to or higher than the melting point of the PAS resin, preferably equal to or higher than the melting point + 10°C, more preferably equal to or higher than the melting point + 10°C, even more preferably equal to or higher than the melting point + 20°C, to a temperature range in which the resin temperature is equal to or lower than the melting point + 100°C, more preferably equal to or lower than the melting point + 50°C.

[0044] From the viewpoint of dispersibility and productivity, the melt kneader is preferably a twin-screw kneading extruder. For example, it is preferable to melt knead while appropriately adjusting the resin component discharge rate in the range of 5 to 500 (kg / hr) and the screw rotation speed in the range of 50 to 500 (rpm). It is even more preferable to melt knead under conditions where the ratio (discharge rate / screw rotation speed) is in the range of 0.02 to 5 (kg / hr / rpm). Furthermore, the addition and mixing of the components to the melt kneader may be carried out simultaneously or in portions. For example, when adding other fibrous fillers as needed, it is preferable from the viewpoint of dispersibility to feed them into the twin-screw kneading extruder through a side feeder. The position of the side feeder is preferably such that the ratio of the distance from the extruder's resin input section (top feeder) to the side feeder to the total screw length of the twin-screw kneading extruder is 0.1 or more, more preferably 0.3 or more. Furthermore, this ratio is preferably 0.9 or less, more preferably 0.7 or less.

[0045] After the melt-kneading, the resin composition is preferably processed by a known method, for example, by extruding the molten resin composition into a strand shape, and then processed into a form such as pellets, chips, granules, or powder, and then pre-dried as necessary.

[0046] In this embodiment, the extrusion molding of the PAS resin composition can be performed by a known method without any particular limitations on the molding conditions, and the composition can be molded by a typical method. For example, the PAS resin composition can be melted in a molding machine at a resin temperature in a range equal to or higher than the melting point of the PAS resin, preferably in a temperature range of at least 10°C above the melting point, more preferably in a temperature range of from the melting point + 10°C to the melting point + 100°C, and even more preferably in a temperature range of from the melting point + 20°C to the melting point + 50°C, and then extrusion molding can be performed. Note that the tubular molded product in this disclosure is a single-layer product and does not include multi-layer tubular molded products of two or more layers.

[0047] The size and shape of the tubular molded product obtained by extrusion molding are not particularly limited as long as they do not impair the effects of the present invention. For example, the length is preferably 100 to 2,000 mm, more preferably 300 to 1,500 mm, and even more preferably 500 to 1,000 mm. The outer diameter is preferably 3 to 30 mm, more preferably 5 to 20 mm, and even more preferably 10 to 15 mm. The wall thickness is preferably 0.1 to 3.0 mm, more preferably 0.3 to 2.0 mm, and even more preferably 0.6 to 1.2 mm.

[0048] In this embodiment, the difference between the maximum outer diameter and the minimum outer diameter (roundness) of the non-bent portion of the tubular molded product is 0.3 mm or less, preferably 0.2 mm or less, and more preferably 0.1 mm or less. Within this range, stress generated when water pressure is applied is dispersed, resulting in excellent water pressure resistance.

[0049] In this embodiment, the tubular molded article obtained by extrusion molding may be bent as it is while being maintained at a temperature equal to or higher than the glass transition temperature of the PAS resin, or may be cooled once to a temperature equal to or lower than the glass transition temperature of the PAS resin and then heated again and bent. The bending may be performed by a known method.

[0050] The PAS resin pipe of the present disclosure is a pipe formed by extrusion molding a PAS resin composition, and has a straight portion and a bent portion.

[0051] In the PAS resin pipe of the present disclosure, the minimum outer diameter of the bent portion is preferably 70% or more of the average outer diameter of the non-bent portion from the viewpoint of durability. From the same viewpoint, it is more preferable that it is 80% or more, and even more preferable that it is 90% or more. To achieve such a numerical value, it is effective for the PAS resin composition to have a low crystallization rate and a large tensile elongation at break. The location of the minimum outer diameter of the bent portion is the location that is most deformed and has the smallest diameter during bending.

[0052] The PAS resin pipe of the present disclosure preferably has a water pressure resistance of 2.0 MPa or more from the viewpoint of durability. From the same viewpoint, it is more preferable that it is 3.0 MPa or more, and even more preferable that it is 5.0 MPa or more. To improve the water pressure resistance, it is effective that the elastic modulus of the resin composition is high, that the pipe has good moldability and high circularity, that the material has a slow crystallization rate so that a thick pipe can be molded, and that the pipe has good bending processability and a large minimum outer diameter at the bent portion.

[0053] From the viewpoint of durability, it is preferable that the arithmetic mean height Sa of the inner wall of the bent portion is 60 μm or less and the maximum height Sz is 350 μm or less. From the same viewpoint, it is more preferable that Sa is 50 μm or less and Sz is 300 μm or less, and even more preferable that Sa is 30 μm or less and Sz is 200 μm or less. In order to improve the smoothness of the inner wall, it is effective for the material to have a low crystallization rate and a large tensile elongation at break.

[0054] <Method for manufacturing composite and composite material> The method for manufacturing a composite according to this embodiment is characterized by having a step of joining the PAS resin pipe manufactured by the method described above to a joint. Furthermore, the composite according to this embodiment is a composite formed by combining the PAS resin pipe and the joint described above. This will be described in detail below.

[0055] The material of the joint used in this embodiment is not particularly limited, and joints formed from known materials such as resin, metal, and ceramic can be used. In particular, when a resin joint is used, the composite has excellent moldability and flexibility, and when a metal joint is used, the composite has excellent mechanical strength. When made of resin, the resin is preferably a thermoplastic resin, more preferably an engineering plastic, and even more preferably a super engineering plastic. Furthermore, when made of resin, the resin may be a resin composition containing optional components other than the resin.

[0056] The shape of the joint that can be applied to this embodiment is not particularly limited, and joints of known shapes can be used, such as socket, nipple, elbow, cap, plug, flange, cross, reducer, bushing, T-shaped, and Y-shaped joints.

[0057] The method for assembling the resin pipe and the fitting is not particularly limited as long as it does not impair the effects of the present invention, and known methods and devices can be used, such as welding the resin pipe and the fitting, crimping the resin pipe and the fitting, mechanically joining the resin pipe and the fitting, and press-fitting the resin pipe and the fitting.

[0058] The method for welding the resin pipe and the joint includes contacting the resin pipe and the joint and then heating them to join them, or heating them and then contacting them to join them and then cooling them.Specific examples of the welding method include hot plate welding, vibration welding, infrared welding, infrared vibration welding, ultrasonic welding, high-frequency welding, induction heating welding, rotary welding, laser welding, hot pressing, hot embossing, and friction stir welding.Commercially available equipment and manufacturing methods can be used for these joining methods, or they can be performed according to conventional methods.

[0059] The method of crimping the resin pipe and the joint includes drilling holes in the resin pipe and the joint, passing a rivet through the hole, and deforming the rivet to fix them. Specific examples include press crimping, spin crimping, and heat crimping. Commercially available devices and manufacturing methods can be used for these joining methods, or conventional methods can be used.

[0060] Methods for mechanically joining the resin pipe and the joint include mechanical fastening using screws, pins, shafts, bolts, nuts, clamps, etc., and fixing with a fitting structure.

[0061] <Composition, Applications, etc.> The resin pipe according to this embodiment is characterized by excellent properties such as water pressure resistance, hot water resistance, and chemical resistance, and is therefore suitable for use in residential equipment such as hot water piping and fuel piping, and in automobile fuel piping. Specifically, it can be suitably used for piping components such as hot water storage tanks for water heaters. Furthermore, the resin pipe according to this embodiment can be used not only for piping components, but also as a pipe for various other applications such as those described below. Examples include electrical and electronic component applications, household and office electrical appliance components, machine-related component applications such as cleaning tools, and automobile and vehicle-related component applications such as various pipes for fuel, exhaust, and intake systems, and can also be used for various other applications.

[0062] The present invention will be specifically described below with reference to examples. These examples are illustrative and not limiting. Unless otherwise specified, "%" and "parts" are based on mass.

[0063] Examples 1 to 3, Comparative Examples 1 to 3 (Production of PPS Resin Composition) Each material was blended according to the composition and blending amounts listed in Table 1. These blending materials were then charged into a vented twin-screw extruder and melt-kneaded at a resin component discharge rate of 30 kg / hr, a screw rotation speed of 200 rpm, and a set resin temperature of 310°C to obtain pellets of the resin composition. The glass fiber was charged through a side feeder (S / T ratio 0.5), and the other materials were uniformly mixed in advance in a tumbler and then charged through the top feeder. The resulting pellets of the resin composition were dried for 2 hours in a gear oven at 140°C.

[0064] (Production of Straight Pipes) Straight pipes were produced using the pellets of each resin composition obtained. The pellets were fed into an extrusion molding machine consisting of a single-screw extruder, a pipe-molding die, a vacuum-capable water-cooling tank, a take-up device, and a cutter. The single-screw extruder was set at a temperature of 300°C, with a sizing diameter of 12.5 mm, a take-up speed of 5.0 m / min, and a cutting interval of 1 m. Pipes having an outer diameter of 12.0 mm, an inner diameter of 10.0 mm, a thickness of 1.0 mm, and a length of 1,500 mm were obtained.

[0065] (Pipe bending) A fluorine tube with an outer diameter of 9.0 mm was inserted into the obtained straight pipe, and after preheating at 210° C. for 10 minutes, it was placed in a mold with a bending angle of 90° and a bending radius of 40 mm and heat-set for 20 minutes at 210° C. After heat-setting, it was allowed to cool, and the bent tube was taken out of the mold and the fluorine tube was removed to obtain a bent pipe.

[0066] <Evaluation>

[0067] (1) Tensile Test Pellets of the resin compositions of each Example and Comparative Example were fed into a Sumitomo Heavy Industries injection molding machine (SE-75D-HP) set at a cylinder temperature of 310°C, and injection molding was carried out using an ISO Type 1A dumbbell piece mold adjusted to a mold temperature of 140°C to obtain ISO Type-A dumbbell pieces. The tensile modulus and tensile break strain of the obtained dumbbell pieces were measured using measurement methods in accordance with ISO 527-1 and 2. The measurement results are shown in Table 1.

[0068] (2) Evaluation of Pipe Moldability The moldability of the resin compositions of each Example and Comparative Example was evaluated based on molding defects (resin breakage, drawdown, or resin generation) that occurred during three hours of continuous extrusion molding under the above-mentioned straight pipe production conditions. Cases where resin breakage occurred were rated C, cases where there was no resin breakage but surface roughness due to drawdown or resin generation occurred were rated B, and cases where neither occurred were rated A. The results are shown in Table 1. In this section, resin breakage refers to the phenomenon in which the resin cannot be stably extruded due to foreign matter or foaming, etc., drawdown refers to the phenomenon in which the strand discharged from the single-screw extruder bends before entering the pipe molding die, and resin refers to foreign matter containing components of the resin composition.

[0069] (3) Measurement of roundness distortion of straight pipes: Sections of 300 mm, 500 mm, and 1000 mm were cut from one end of the prepared straight pipe. The maximum and minimum outer diameters of all cut pipes were measured using a one-shot 3D shape measuring instrument (VR5200) manufactured by Keyence Corporation, and the difference between the maximum and minimum outer diameters was taken as the roundness distortion. The results are shown in Table 1.

[0070] (4) Evaluation of bending workability (degree of deformation) Five bent pipes from each Example and Comparative Example were cut at the center of the non-bent portion and the bent portion to prepare test pieces. The average outer diameter of the non-bent portion and the minimum outer diameter at the center of the bent portion were measured using a one-shot 3D shape measuring machine "VR5200" manufactured by Keyence Corporation, and the degree of deformation was calculated from (minimum outer diameter of the bent portion) / (average outer diameter of the non-bent portion) × 100.

[0071] (5) Evaluation of water pressure resistance of bent pipe One end of the bent pipe was sealed with adhesive and filled with water. The other end of the pipe (the unsealed end) was connected to a water pressure test pump (TP-50 manufactured by Terada Pump Manufacturing Co., Ltd.), and the pressure was increased at 5 MPa / min to measure the pressure at which the pipe burst. The results are shown in Table 1.

[0072] (6) Evaluation of fitting press-fitting properties: A section 1 mm from each end of the bent pipe was flared to an inner diameter of 10 to 12 mm, and a fitting with a barb diameter of 13 mm was pressed into the fitting at room temperature at a speed of 100 mm / sec so that the center of the circle and the center of the fitting were aligned. Samples that cracked during press-fitting were rated C, samples that were inserted without cracking but whitened due to deformation were rated B, and samples that were inserted cleanly without whitening were rated A. The results are shown in Table 1.

[0073]

[0074] The following compounds were used for each of the components in Table 1: B-1: Ethylene-glycidyl methacrylate thermoplastic elastomer, "Bondfast 7M" manufactured by Sumitomo Chemical Co., Ltd. B-2: Ionomer thermoplastic elastomer, "Himilan (registered trademark) AM7327" manufactured by Mitsui Dow Polychemicals Co., Ltd.

[0075] (Production Example 1: Synthesis of PPS Resin A-1) 22.050 kg (150 mol) of p-dichlorobenzene (p-DCB), 2.974 kg (30 mol) of N-methyl-2-pyrrolidone (NMP), 12.362 kg (150 mol) of 68% NaSH, and 12.500 kg (150 mol) of 48% NaOH were fed into a 150 L autoclave equipped with a pressure gauge, a thermometer, a stirring blade connected to a condenser and a decanter, and a bottom valve, and the temperature was raised to 173°C under a nitrogen atmosphere with stirring. Then, 12.353 kg of water was distilled off, and the kettle was sealed. The p-DCB distilled off by azeotropy was separated in the decanter and returned to the kettle as needed. After dehydration was completed, the autoclave was cooled to 160 ° C., and 29.486 kg (297 mol) of NMP was added. The temperature was then increased to 220 ° C. and stirred for 2 hours, and then increased to 250 ° C. and stirred for 1 hour. The final pressure was 0.28 MPa. After the reaction was completed, the bottom valve of the autoclave was opened and the mixture was flushed into a 150 L vacuum agitator with an agitator blade to remove the NMP. The mixture was then stirred under reduced pressure at 150 ° C. for 4 hours to thoroughly remove the NMP, yielding a mixture of powdered PPS resin and salts. 90 kg of 70 ° C. ion-exchanged water was added to 30 kg of the resulting crude PPS mixture, stirred for 30 minutes, and then filtered. 90 kg of 70 ° C. ion-exchanged water was added to the filtered cake to wash the cake. The obtained hydrous cake and 60 kg of ion-exchanged water were then charged into a 100 L autoclave equipped with a stirring blade. The pH was adjusted to 4 with hydrochloric acid, and the mixture was heated to 230°C over 2 hours with stirring, extracted with stirring for 30 minutes, and cooled to room temperature. The entire mixture was filtered, and 90 kg of ion-exchanged water at 70°C was added to the filtered cake for cake washing. The cake was then dried at 120°C for 4 hours to obtain a white powdery PPS resin. The resulting PPS resin A-1 had a weight-average molecular weight of 22,000, a melt viscosity of 35 Pa s, and a cooling crystallization temperature of 240°C.

[0076] (Production Example 2: Synthesis of PPS Resin A-2) PPS Resin A-2 was produced in the same manner as Resin A-1, except that 21.756 kg (147 mol) of p-DCB was used and pH adjustment with hydrochloric acid was not performed during hot water washing at 230° C. The resulting PPS Resin A-2 had a weight average molecular weight of 40,000, a melt viscosity of 115 Pa s, and a crystallization temperature upon cooling of 200° C.

Claims

1. A resin pipe having a non-bent portion and a bent portion, which is obtained by bending a single-layer tubular molded product made of a polyarylene sulfide resin composition at a temperature above the glass transition point of the polyarylene sulfide resin, wherein the tensile elongation at break of the polyarylene sulfide resin composition is 70% or more, and the minimum outer diameter of the bent portion is 70% or more of the average outer diameter of the non-bent portion.

2. A polyarylene sulfide resin pipe according to claim 1, wherein the difference between the maximum outer diameter and the minimum outer diameter of the non-bent portion of said tubular molded product is 0.3 mm or less.

3. A polyarylene sulfide resin pipe according to claim 1 or 2, wherein the arithmetic mean height Sa of the inner wall of the bent portion is 60 μm or less and the maximum height Sz is 350 μm or less.

4. A polyarylene sulfide resin pipe according to claim 1 or 2, wherein the content of the polyarylene sulfide resin is 75 parts by mass or more per 100 parts by mass of the polyarylene sulfide resin composition.

5. A polyarylene sulfide resin pipe according to claim 1 or 2, wherein the polyarylene sulfide resin composition has a tensile modulus of elasticity of 1.0 GPa or more.

6. A polyarylene sulfide resin pipe according to claim 1 or 2, wherein the polyarylene sulfide resin composition has an MFR of 10 g / 10 min or less (wherein the MFR is a value measured at a temperature of 315°C and a load of 2.16 kg).

7. A polyarylene sulfide resin pipe according to claim 1 or 2, wherein the polyarylene sulfide resin composition has a crystallization temperature upon cooling of 230°C or less (wherein the crystallization temperature upon cooling is the peak top value of the exothermic peak observed when the composition is melted at 350°C for 3 minutes and then cooled to 40°C at a rate of 20°C / min using a differential scanning calorimeter).

8. A polyarylene sulfide resin pipe according to claim 1 or 2, wherein said polyarylene sulfide resin composition further contains a thermoplastic elastomer.

9. A polyarylene sulfide resin pipe according to claim 1 or 2, having a water pressure resistance of 2.0 MPa or more (wherein the water pressure resistance is a value measured in accordance with JIS S-3200-1).

10. A composite comprising a polyarylene sulfide resin pipe according to claim 1 or 2 and a joint.

11. A method for producing a resin pipe, comprising the steps of: extruding a polyarylene sulfide resin composition to obtain a single-layer tubular molded product; and bending the tubular molded product at a temperature equal to or higher than the glass transition point of the polyarylene sulfide resin to form a bent portion, wherein the difference between the maximum outer diameter and the minimum outer diameter of the non-bent portion of the tubular molded product is 0.3 mm or less, and the content of polyarylene sulfide resin per 100 parts by mass of the polyarylene sulfide resin composition is 75 parts by mass or more.

12. The method for producing a polyarylene sulfide resin pipe according to claim 11, wherein the minimum outer diameter of the bent portion is 70% or more of the average outer diameter of the non-bent portion.

13. A method for producing a polyarylene sulfide resin pipe according to claim 11 or 12, wherein the arithmetic mean height Sa of the inner wall of the bent portion is 60 μm or less and the maximum height Sz is 350 μm or less.

14. The method for producing a polyarylene sulfide resin pipe according to claim 11 or 12, wherein the tensile elongation at break of the polyarylene sulfide resin composition is 70% or more.

15. The method for producing a polyarylene sulfide resin pipe according to claim 11 or 12, wherein the tensile modulus of the polyarylene sulfide resin composition is 1.0 GPa or more.

16. The method for producing a polyarylene sulfide resin pipe according to claim 11 or 12, wherein the polyarylene sulfide resin composition has an MFR of 10 g / 10 min or less (wherein the MFR is a value measured at a temperature of 315°C and a load of 2.16 kg).

17. The method for producing a polyarylene sulfide resin pipe according to claim 11 or 12, wherein the polyarylene sulfide resin composition has a crystallization temperature upon cooling of 230°C or lower (wherein the crystallization temperature upon cooling is the peak top value of the exothermic peak observed when the composition is melted at 350°C for 3 minutes and then cooled to 40°C at 20°C / min using a differential scanning calorimeter).

18. The method for producing a polyarylene sulfide resin pipe according to claim 11 or 12, wherein the polyarylene sulfide resin composition further contains a thermoplastic elastomer.

19. A polyarylene sulfide resin pipe according to claim 11 or 12, having a water pressure resistance of 2.0 MPa or more (wherein the water pressure resistance is a value measured in accordance with JIS S-3200-1).

20. A method for producing a composite, comprising the step of joining a polyarylene sulfide resin pipe produced by the method of claim 11 or 12 to a joint.