Resin composition for refrigerant transport hoses and refrigerant transport hose

Abstract

Resin composition for a refrigerant transport hose, wherein the resin composition comprises: a thermoplastic resin; and an elastomer; wherein the thermoplastic resin and the elastomer form an island-in-the-sea structure consisting of a matrix of the thermoplastic resin and an area of ​​the elastomer, wherein the resin composition includes a P(O2), an M10, and a P(H2O) that satisfy formulas 1 and 2: 0 < P ( O 2 ) × M10 ≤ 150 and log(P(H2O) / P(O2)) ≤ 0.9 , where P(O2) is an oxygen permeability coefficient [cm·cm 3 / (cm 2 ·s·cmHg)] at a temperature of 21 °C and a relative humidity of 50 %, M10 is a 10 % modulus [MPa] at a temperature of 25 °C and P(H2O) is a water vapor permeability coefficient [cm·cm 3 / (cm 2·s·cmHg)] at a temperature of 60 °C and a relative humidity of 100%, wherein the thermoplastic resin is at least one selected from the group consisting of a polyamide resin, a polyester resin, a vinyl alcohol resin and a polyketone resin, wherein the elastomer is at least one selected from the group consisting of a butyl rubber, a modified butyl rubber, an olefin thermoplastic elastomer, a styrene-based thermoplastic elastomer, a polyamide elastomer and a polyester elastomer, wherein the resin composition comprises at least one processing aid selected from the group consisting of a fatty acid, a fatty acid metal salt, a fatty acid ester and a fatty acid amide.

Description

Technical field

[0001] The present invention relates to a resin composition for a refrigerant transport hose and a refrigerant transport hose. State of the art

[0002] With the increasing demand for weight reduction in automobiles, efforts have been made to achieve this by manufacturing rubber hoses used in automobiles from a resin with high barrier properties, thus reducing their thickness. In particular, the main material of the refrigerant transport hose in current vehicle air conditioning systems is rubber, and if this main material can be replaced by a resin with high barrier properties, weight reduction can be achieved.

[0003] For example, patent document 1 describes a refrigerant transport hose in which an innermost layer is formed from a resin layer having an island-in-the-sea structure. The island-in-the-sea structure comprises a sea phase, mainly containing a nylon resin, and an island phase, containing a copolymer of isobutylene and p-methylstyrene in which one or more hydrogen atoms in the molecule are halogenated. Patent document 2 describes a pipe for transporting a fluid, wherein the pipe has reduced vapor permeability and excellent air permeability by using a thermoplastic elastomer as the base material to which a carbon-based filler is added. Patent document 3 describes an ink tube for an inkjet printer, which is used to discharge excess ink to the outside of an inkhead when the inkhead of the inkjet printer is cleaned.Patent document 4 describes a hose for a refrigerant with an innermost layer of a copolymer and a rubber layer arranged on the outer circumference of the innermost layer. Patent document 5 describes a refrigerant transport hose consisting of a resin layer with an islands-in-the-sea structure, containing a copolymer with styrene, in particular a halogenated IB-PMS copolymer. Patent document 6 describes an EVOH-based composite resin with which a hose for transporting a refrigerant can be manufactured, exhibiting improved gas barrier properties and flexibility, as well as high durability.Patent document 7 describes a refrigerant transport hose comprising an inner pipe layer with a gas barrier layer and a rubber layer adjacent to the outer surface of the gas barrier layer, wherein the gas barrier layer is formed using a thermoplastic resin composition comprising a polyamide resin and a modified rubber with an acid anhydride group or an epoxy group, wherein the modified rubber is obtained by modifying a modified raw rubber with an acid anhydride group or an epoxy group with a hydrogen bond-forming compound having a functional group that reacts with the acid anhydride group or the epoxy group and a functional group that can form a hydrogen bond with an amide bond or a hydroxyl group. List of literature on patent literature Patent document 1: JP 3 208 920 B Patent document 2:US 2010 / 0 233 400 A1 Patent document 3: US 2004 / 0 134 554 A1 Patent document 4: DE 11 2017 005 273 B4 Patent Document 5: JP H06-294 484 A Patent document 6: JP 2007- 9 171 A Patent document 7: EP 2 620 273 A1 Brief description of the invention: Technical problem

[0004] Examples of resins exhibiting high barrier properties include ethylene-vinyl alcohol copolymers and polyamides. An ethylene-vinyl alcohol copolymer alone, or polyamide alone, does not readily allow oxygen to penetrate, but does allow water vapor to penetrate easily. An object of the present invention is to provide a resin composition that can achieve a balanced combination of low gas permeability, flexibility, and low water vapor permeability for a refrigerant transport hose. Solution to the problem

[0005] A first embodiment of the present invention is a resin composition for a refrigerant transport hose, wherein the resin composition comprises: a thermoplastic resin; and an elastomer; wherein the thermoplastic resin and the elastomer form an island-in-the-sea structure consisting of a matrix of the thermoplastic resin and an area of ​​the elastomer, wherein the resin composition includes a P(O2), an M10, and a P(H2O) that satisfy formulas 1 and 2: 0 <P(O2)×M10≤150 and log(P(H2O) / P(O2))≤0.9 , where P(O2) is an oxygen permeability coefficient [cm·cm 3 / (cm 2 ·s·cmHg)] at a temperature of 21 °C and a relative humidity of 50 %, M10 is a 10 % modulus [MPa] at a temperature of 25 °C and P(H2O) is a water vapor permeability coefficient [cm·cm 3 / (cm 2·s·cmHg)] at a temperature of 60 °C and a relative humidity of 100%, wherein the thermoplastic resin is at least one selected from the group consisting of a polyamide resin, a polyester resin, a vinyl alcohol resin and a polyketone resin, wherein the elastomer is at least one selected from the group consisting of a butyl rubber, a modified butyl rubber, an olefin thermoplastic elastomer, a styrene-based thermoplastic elastomer, a polyamide elastomer and a polyester elastomer, wherein the resin composition comprises at least one processing aid selected from the group consisting of a fatty acid, a fatty acid metal salt, a fatty acid ester and a fatty acid amide.

[0006] A second embodiment of the present invention is a refrigerant transport hose which encloses a layer of the resin composition of the first embodiment of the present invention.

[0007] The present invention includes the following embodiments. [1] A resin composition for a refrigerant transport hose, wherein the resin composition comprises: a thermoplastic resin; and an elastomer; wherein the thermoplastic resin and the elastomer form an island-in-the-sea structure consisting of a matrix of the thermoplastic resin and an area of ​​the elastomer, wherein the resin composition includes a P(O2), an M10, and a P(H2O) that satisfy formulas 1 and 2: 0 <P(O2)×M10≤150 and log(P(H2O) / P(O2))≤0.9 , where P(O2) is an oxygen permeability coefficient [cm·cm 3 / (cm 2·s·cmHg)] at a temperature of 21 °C and a relative humidity of 50 %, M10 is a 10 % modulus [MPa] at a temperature of 25 °C and P(H2O) is a Water vapor permeability coefficient [cm·cm²] 3 / (cm 2·s·cmHg)] at a temperature of 60 °C and a relative humidity of 100%, wherein the thermoplastic resin is at least one selected from the group consisting of a polyamide resin, a polyester resin, a vinyl alcohol resin and a polyketone resin, wherein the elastomer is at least one selected from the group consisting of a butyl rubber, a modified butyl rubber, an olefin thermoplastic elastomer, a styrene-based thermoplastic elastomer, a polyamide elastomer and a polyester elastomer, wherein the resin composition comprises at least one processing aid selected from the group consisting of a fatty acid, a fatty acid metal salt, a fatty acid ester and a fatty acid amide.

[0008] [2] The resin composition for a refrigerant transport hose according to [1], wherein the water vapor permeability coefficient P(H2O) at a temperature of 60 °C and a relative humidity of 100 % is 60 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg) or less.

[0009] [3] The resin composition for a refrigerant transport hose according to [1] or [2], wherein the oxygen permeability coefficient P(O2) at a temperature of 21 °C and a relative humidity of 50 % is 20 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg) or less.

[0010] [4] The resin composition for a refrigerant transport hose according to one of [1] to [3], wherein the 10% modulus M10 is 10 MPa or less at a temperature of 25 °C.

[0011] [5] The resin composition for a refrigerant transport hose according to one of [1] to [4], wherein an oxygen permeability coefficient PR (O2) [cm·cm 3 / (cm 2 ·s·cmHg)] of the thermoplastic resin at a temperature of 21 °C and a relative humidity of 50 % and a water vapor permeability coefficient P R (H2O) [cm·cm 3 / (cm 2 ·s·cmHg)] of the thermoplastic resin at a temperature of 60 °C and a relative humidity of 100 % must meet formula 3: log(PR(H2O) / PR(O2))≤5.0 .

[0012] [6] The resin composition for a refrigerant transport hose according to one of [1] to [5], wherein an oxygen permeability coefficient P R (O2) [cm·cm 3 / (cm 2 ·s·cmHg)] of the elastomer at a temperature of 21 °C and a relative humidity of 50 % and a water vapor permeability coefficient P R (H2O) [cm·cm 3 / (cm 2 ·s·cmHg)] of the elastomer at a temperature of 60 °C and a relative humidity of 100 % must meet formula 4: log(PE(H2O) / PE(O2))≤1.5 . Advantageous effects of the invention

[0013] The resin composition according to one embodiment of the present invention exhibits low gas permeability and flexibility, which are required for the refrigerant transport hose, and also exhibits excellent water vapor permeability. Description of embodiments

[0014] A first embodiment of the present invention is a resin composition for a refrigerant transport hose, wherein the resin composition comprises: a thermoplastic resin; and an elastomer; wherein the thermoplastic resin and the elastomer form an island-in-the-sea structure consisting of a matrix of the thermoplastic resin and an area of ​​the elastomer, wherein the resin composition includes a P(O2), an M10, and a P(H2O) that satisfy formulas 1 and 2: 0 <P(O2)×M10≤150 and log(P(H2O) / P(O2))≤0.9 , where P(O2) is an oxygen permeability coefficient [cm·cm 3 / (cm 2 ·s·cmHg)] at a temperature of 21 °C and a relative humidity of 50 %, M10 is a 10 % modulus [MPa] at a temperature of 25 °C and P(H2O) is a water vapor permeability coefficient [cm·cm 3 / (cm 2·s·cmHg)] at a temperature of 60 °C and a relative humidity of 100%, wherein the thermoplastic resin is at least one selected from the group consisting of a polyamide resin, a polyester resin, a vinyl alcohol resin and a polyketone resin, wherein the elastomer is at least one selected from the group consisting of a butyl rubber, a modified butyl rubber, an olefin thermoplastic elastomer, a styrene-based thermoplastic elastomer, a polyamide elastomer and a polyester elastomer, wherein the resin composition comprises at least one processing aid selected from the group consisting of a fatty acid, a fatty acid metal salt, a fatty acid ester and a fatty acid amide.

[0015] The first embodiment of the present invention relates to the resin composition for a refrigerant transport hose, wherein the resin composition comprises a thermoplastic resin and an elastomer. The term refrigerant transport hose refers to a hose for transporting a refrigerant for an air conditioning system or the like. The resin composition according to one embodiment of the present invention is particularly suitable for manufacturing a hose for transporting a refrigerant for an air conditioning system of a motor vehicle. A refrigerant transport hose typically consists of an inner tube, a reinforcing layer, and an outer tube, and the thermoplastic resin composition according to one embodiment of the present invention is particularly suitable for manufacturing, in particular, the inner tube of the refrigerant transport hose.Examples of refrigerants for an air conditioning system include hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), hydrocarbons, carbon dioxide, and ammonia. Examples of HFCs include R410A, R32, R404A, R407C, R507A, and R134a. Examples of HFOs include R1234yf, R1234ze, R1233zd, R1123, R1224yd, and R1336mzz. Examples of hydrocarbons include methane, ethane, propane, propylene, butane, isobutane, hexafluoropropane, and pentane. In embodiments of the present invention, the term "low gas permeability" refers to a property in which gas, such as the refrigerant described above, is less likely to pass through.

[0016] In a refrigerant transport hose used in the air conditioning system of a motor vehicle or similar, permeation of water and / or water vapor from the outside of the hose causes moisture inside the air conditioning system to freeze. Therefore, a material with excellent low permeability to water and / or water vapor is required, and prior art uses butyl rubber, ethylene / propylene copolymer rubber, or similar materials.

[0017] The resin composition according to one embodiment of the present invention comprises a thermoplastic resin and an elastomer, and the thermoplastic resin and the elastomer form an islands-in-the-sea structure consisting of a matrix of the thermoplastic resin and a region of the elastomer. In other words, the resin composition according to one embodiment of the present invention consists of a matrix and a region dispersed in the matrix. The ratios between the matrix and the region are not limited as long as the effects of the present invention are achieved, but preferably the volume ratio of the matrix in the resin composition is 25 to 50 vol%, and the volume ratio of the region in the resin composition is 50 to 75 vol%. The volume ratio of the matrix in the resin composition is more preferably 25 to 40 vol%, and even more preferably 30 to 40 vol%.In a case where the matrix volume ratio is too low, a phase inversion of the matrix and the area would occur, and the islands-in-the-sea structure could reverse. If the matrix volume ratio is too high, the content of the thermoplastic resin forming the matrix would increase, preventing the desired flexibility from being achieved.

[0018] In the resin composition according to one embodiment of the present invention, an oxygen permeability coefficient P(O2) [cm·cm] is fulfilled. 3 / (cm 2 ·s·cmHg)] at a temperature of 21 °C and a relative humidity of 50 % and a 10-% modulus M10 [MPa] at a temperature of 25 °C the following formula: 0 <P(O2)×M10≤150 preferably fulfill: 5≤P(O2)×M10≤130 and fulfill more preferred: 10≤P(O2)×M10≤110

[0019] The resin composition with a P(O2) and an M10 that meet Formula 1 provides a hose that has low gas permeability, is flexible and has excellent handling.

[0020] In the resin composition according to one embodiment of the present invention, an oxygen permeability coefficient P(O2) [cm·cm] is fulfilled. 3 / (cm 2 ·s·cmHg)] at a temperature of 21 °C and a relative humidity of 50 % and a water vapor permeability coefficient P(H2O) [cm·cm 3 / (cm 2 ·s·cmHg)] at a temperature of 60 °C and a relative humidity of 100 % the following formula: log(P(H2O) / P(O2))≤0.9 preferably fulfill: 0.2≤log(P(H2O) / P(O2))≤0.7 and fulfill more preferred: 0.2≤log(P(H2O) / P(O2))≤0.7

[0021] The resin composition with a P(H2O) and a P(O2) that fulfill formula 2 provides a hose that has low gas permeability as well as reduced penetration of moisture into the interior due to water vapor permeation.

[0022] In the resin composition according to one embodiment of the present invention, the oxygen permeability coefficient P(O2) at a temperature of 21 °C and a relative humidity of 50 % is preferably 20 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg) or less, preferably 18 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg) or less, and preferably 15 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg) or less. The lower limit of P(O2) is not restricted, but P(O2) is usually 0.001 × 10 -12 cm·cm 3 / (cm 2·s·cmHg) or more. If the P(O2) is within the range listed above, this provides a tube that the refrigerant gas is less likely to penetrate.

[0023] The oxygen permeability coefficient is a measure of low gas permeability; lower oxygen permeability coefficients indicate superior low gas permeability, and higher oxygen permeability coefficients indicate poorer low gas permeability. The method for measuring oxygen permeability is not particularly limited, but the oxygen permeability coefficient can be measured, for example, using an OXTRAN 1 / 50, available from MOCON, Inc.

[0024] In the resin composition according to one embodiment of the present invention, the water vapor permeability coefficient P(H2O) at a temperature of 60 °C and a relative humidity of 100 % is preferably 60 × 10-12 cm·cm 3 / (cm 2 ·s·cmHg) or less, preferably 50 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg) or less and preferably 40 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg) or less. The lower limit of P(H2) is not restricted, but P(H2) is usually 0.1 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg) or more. If the P(H2O) is within the range listed above, this can reduce the penetration of moisture into the interior of the hose due to water vapor permeation.

[0025] The method for measuring the water vapor permeability coefficient is not particularly limited, but the water vapor permeability coefficient can be measured, for example, using a water vapor permeation test available from GTR Tech Corporation.

[0026] In the resin composition according to one embodiment of the present invention, a 10% modulus M10 at a temperature of 25 °C is preferably 10 MPa or less, more preferably 9 MPa or less, and even more preferably 8 MPa or less. The lower limit of the M10 is not restricted, but the M10 is typically 0.1 MPa or more. If the M10 is within the range specified above, this results in a hose that is flexible and exhibits excellent handling.

[0027] The 10% modulus can be measured according to JIS K6301, “Physical Testing Method for Vulcanized Rubber”.

[0028] The thermoplastic resin that forms the matrix must meet an oxygen permeability coefficient P. R (O2) [cm·cm 3 / (cm 2 ·s·cmHg)] at a temperature of 21 °C and a relative humidity of 50 % and a water vapor permeability coefficient P R (H2O) [cm·cm 3 / (cm 2 ·s·cmHg)] at a temperature of 60 °C and a relative humidity of 100 % preferably: log(PR(H2O) / PR(O2))≤5.0 fulfill more preferred: 0.1≤log(PR(H2O) / PR(O2))≤4.5 and even more preferred: 0.2≤log(PR(H2O) / PR(O2))≤4.0

[0029] With the thermoplastic resin with a P R (O2) and a water vapor permeability coefficient P R (H2O), which fulfill formula 3, allows the resin composition produced by combining the thermoplastic resin with the elastomer to easily be given both low gas permeability and low water vapor permeability.

[0030] The thermoplastic resin is not limited as long as the resin composition satisfies formulas 1 and 2 and the thermoplastic resin satisfies formula 3. According to the invention, the thermoplastic resin is at least one selected from the group consisting of a polyamide resin, a polyester resin, a vinyl alcohol resin, and a polyketone resin.

[0031] Examples of the polyamide resin include Nylon 6, Nylon 6 / 12 copolymers, Nylon 11, Nylon 12, Nylon 66, Nylon 610, Nylon-6 / 66 copolymers, Nylon 46, Nylon 6T, Nylon 9T, Nylon and MXD6, wherein the polyamide resin is preferably Nylon 6, a Nylon-6 / 12 copolymer or Nylon 12.

[0032] Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and polybutylene naphthalate, wherein the polyester resin is preferably polybutylene terephthalate.

[0033] Examples of vinyl alcohol resins include polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymers (EVOHs), ethylene-vinyl acetate-vinyl alcohol copolymers, and ethylene-butenediol copolymers. Among these, an ethylene-vinyl alcohol copolymer is preferred. The melting point and oxygen permeability coefficient of the ethylene-vinyl alcohol copolymer vary depending on the copolymerization ratio of ethylene and vinyl alcohol. A preferred copolymerization ratio of ethylene is 25 to 48 mol%. Among these, an ethylene-vinyl alcohol copolymer with an ethylene copolymerization ratio of 48 mol% or an ethylene-vinyl alcohol copolymer with an ethylene copolymerization ratio of 38 mol% is preferred.

[0034] Examples of the polyketone resin include ketone-ethylene copolymers and ketone-ethylene propylene terpolymers, wherein the polyketone resin is preferably a ketone-ethylene propylene terpolymer.

[0035] The matrix may contain a thermoplastic resin that does not satisfy formula 3, or an additive of a different type within a range that does not inhibit the effects of the present invention.

[0036] The elastomer that forms the area fulfills an oxygen permeability coefficient P E (O2) [cm·cm 3 / (cm 2 ·s·cmHg)] at a temperature of 21 °C and a relative humidity of 50 % and a water vapor permeability factor P E (H2O) [cm·cm 3 / (cm 2 ·s·cmHg)] at a temperature of 60 °C and a relative humidity of 100 % preferably: log(PE(H2O) / PE(O2))≤1.5 fulfill more preferred: -2.5≤log(PE(H2O) / PE(O2))≤1.0 and even more preferred: -2.0≤log(PE(H2O) / PE(O2))≤0.5

[0037] With the elastomer with a P E(O2) and a water vapor permeability coefficient P E (H2O), which fulfill formula 4, can easily impart both low gas permeability and low water vapor permeability to the resin composition produced by combining the elastomer with the thermoplastic resin.

[0038] The elastomer is not restricted as long as the resin composition fulfills formulas 1 and 2 and the elastomer fulfills formula 4, wherein the elastomer according to the invention is at least one selected from the group consisting of a butyl rubber, a modified butyl rubber, a thermoplastic elastomer, a styrene-based thermoplastic elastomer, an ethylene unsaturated carboxylate copolymer, a polyamide elastomer and a polyester elastomer.

[0039] Butyl rubber (IIR) is an isobutene-isoprene copolymer and can be produced by copolymerization of isobutylene and a small amount of isoprene using a Friedel-Crafts catalyst at a low temperature of or around -95 °C in a methyl chloride solvent.

[0040] The term modified butyl rubber refers to a rubber obtained by modifying butyl rubber, and specific examples include halogenated butyl rubbers and halogenated isobutylene-p-methylstyrene copolymers. Among others, a brominated isobutylene-p-methylstyrene copolymer is preferred.

[0041] Examples of thermoplastic olefin elastomers include ethylene-α-olefin copolymers or ethylene-unsaturated carboxylic acid copolymers or their derivatives. Examples of ethylene-o-olefin copolymers include ethylene-propylene copolymers, ethylene-butene copolymers, ethylene-pentene copolymers, ethylene-hexene copolymers, ethylene-octene copolymers, and their acid-modified products. Examples of ethylene-unsaturated carboxylic acid copolymers include ethylene-acrylic acid copolymers and ethylene-methacrylic acid copolymers.

[0042] Examples of the styrene-based thermoplastic elastomer include styrene-butadiene-styrene block copolymers (SBSs), styrene-isoprene-styrene block copolymers (SISs), styrene-ethylene / propylene-styrene copolymers (SEPSs), styrene-ethylene-butylene-styrene copolymers (SEBS), styrene-butadiene-styrene copolymers (SBSs), styrene-isobutylene-styrene block copolymers (SIBSs), and their maleic anhydride-modified products. Among these, a styrene-isobutylene-styrene block copolymer (SIBS) or a maleic anhydride-modified styrene-ethylene / butylene-styrene block copolymer is preferred.

[0043] Examples of the ethylene unsaturated carboxylate copolymer include ethylene-methyl acrylate copolymers, ethylene-methyl methacrylate copolymers, ethylene-ethyl acrylate copolymers, ethylene-ethyl methacrylate copolymers, ethylene-butyl methacrylate copolymers, ethylene-butyl methacrylate copolymers, and their acid-modified products. Among these, a maleic anhydride-modified ethylene-ethyl acrylate copolymer is preferred.

[0044] The polyamide elastomer (TPA) is a thermoplastic elastomer comprising a hard segment of polyamide (e.g., Nylon 6, Nylon 66, Nylon 11, or Nylon 12) and a soft segment of polyether (e.g., polyethylene glycol or polypropylene glycol). Polyamide elastomers are commercially available, and a commercially available product can be used in embodiments of the present invention. Examples of commercially available polyamide elastomers include “UBESTA” (trade name), XPA series, available from Ube Industries, Ltd., and “PEBAX” (trade name), available from Arkema KK.

[0045] The polyester elastomer (TPEE) is a thermoplastic elastomer comprising a hard segment of polyester (e.g., polybutylene terephthalate) and a soft segment of polyether (e.g., polytetramethylene glycol) or polyester (e.g., aliphatic polyester). Polyester elastomers are commercially available, and a commercially available product can be used in embodiments of the present invention. Examples of commercially available polyester elastomers include “Pelpren” (trade name), available from Toyobo Co., Ltd., and “Hytrel” (trade name), available from DuPont-Toray Co., Ltd.

[0046] The area may contain an elastomer that does not satisfy formula 4 or an additive of a different type within an area that does not inhibit the effects of the present invention.

[0047] The resin composition according to one embodiment of the present invention preferably further comprises at least one processing aid selected from the group consisting of a fatty acid, a fatty acid metal salt, a fatty acid ester, and a fatty acid amide. The inclusion of the processing aid can further improve the extrudability of the resin composition. Examples of the fatty acid include stearic acid, palmitic acid, and oleic acid, with stearic acid being preferred. Examples of the fatty acid metal salt include calcium stearate, magnesium stearate, zinc stearate, and barium stearate. Among these, calcium stearate and magnesium stearate are preferred.Examples of fatty acid esters include fatty acid esters obtained by esterification of a higher fatty acid and a lower alcohol, a higher alcohol, or a polyhydric alcohol, the higher fatty acid being obtained by hydrolysis of coconut oil, castor oil, palm oil, beef tallow, or the like. Examples of fatty acid amides include stearylamide, palmitamide, and oleylamide.

[0048] The amount of processing aid is preferably 0.5 to 5 parts by mass, more preferably 1 to 4 parts by mass, and even more preferably 1 to 3.5 parts by mass per 100 parts by mass of the elastomer in the resin composition. If the concentration is too high, the barrier properties of the resin composition may deteriorate. The processing aid can be present either in the matrix or in the region, or in both.

[0049] The resin composition according to the present invention contains a crosslinking agent. A crosslinking agent suitable for a typical rubber can be used as the crosslinking agent. Examples include sulfur; divalent metal oxides; diamines; peroxides; and resins for vulcanization, such as modified alkylphenols. Among these, zinc oxide is preferred. The crosslinking agent serves to improve processability by crosslinking the elastomer in the resin composition and stabilizing the islands-in-the-sea structure.

[0050] The resin composition according to one embodiment of the present invention may contain an aging retarder. Examples of the aging retarder include amine aging retarders such as amine ketones, diallylamine, and p-phenylenediamine compounds; and phenolic aging retarders such as monophenolic compounds, polyphenolic compounds, and hydroquinone compounds. Among these, N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD), which is a p-phenylenediamine compound, is preferred.

[0051] The method for producing the resin composition according to an embodiment of the present invention is not particularly limited, and the resin composition can be produced by kneading the thermoplastic resin and the elastomer and optionally an additive such as a processing aid, a crosslinking agent and an aging retardant using a twin-screw extruder or the like.

[0052] A second embodiment of the present invention is a refrigerant transport hose that encloses a layer of the resin composition of the first embodiment of the present invention. The refrigerant transport hose according to one embodiment of the present invention is preferably used as a hose for transporting a refrigerant from an air conditioning system and more preferably as a hose for transporting a refrigerant from an air conditioning system of a motor vehicle.

[0053] The refrigerant transport hose preferably comprises an inner tube, a reinforcing layer, and an outer tube. In the refrigerant transport hose according to one embodiment of the present invention, at least one layer of the inner tube is made of the thermoplastic resin composition. The method for manufacturing a refrigerant transport hose is not particularly limited, but the refrigerant transport hose can be manufactured as follows: First, the inner tube is extruded into a tubular shape by extrusion dies; then, a fiber, which is to serve as a reinforcing layer, is braided onto the tube; and furthermore, the fiber is covered with the outer tube by extrusion dies. Examples of raw materials

[0054] The starting materials used in the following examples and comparative examples are as follows. Thermoplastic resin

[0055] Ny6: Nylon 6, “UBE Nylon” 1022 B, available from Ube Industries, Ltd., P R (O2): 1.0 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), P R (H2O) : 65.1 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), log(P R (H2O) / P R (O2)) = 1.81 Ny6 / 12: Nylon-6 / 12 copolymer, “UBE Nylon” 7024B, available from Ube Industries, Ltd., P R (O2) : 3.0 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), P R (H2O) : 62.0 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), log(P R (H2O) / P R (O2)) = 1.32 Ny11: Nylon 11, “RILSAN” (trade name) BESNO TL, available from Arkema KK, P R (O2) : 17.2 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), P R (H2O) : 42.6 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), log(P R (H2O) / P R(O2)) = 0.39 Ny12: Nylon 12, “UBESTA” (trade name) 3012U, available from Ube Industries, Ltd., P R (O2) : 20.2 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), P R (H2O) : 41.8 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), log(P R (H2O) / P R (O2)) = 0.32 EVOH-1: Ethylene-vinyl alcohol copolymer (ethylene content 48 mol%), “Soanol” (trade name) H4815B, available from Nippon Synthetic Chemical Industry Co., Ltd., P R (O2) : 0.07 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), P R (H2O) : 31.0 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), log(P R (H2O) / P R (O2)) = 2.64 EVOH-2: Ethylene-vinyl alcohol copolymer (ethylene content 38 mol%), “Soanol” (trade name) E3808, available from Nippon Synthetic Chemical Industry Co., Ltd., P R (O2) : 0.01 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), P R (H2O) : 34.9 × 10 -12cm·cm 3 / (cm 2 ·s·cmHg), log(P R (H2O) / P R (O2)) = 3.54 PBT: Poly-butylene terephthalate, “NOVADURAN” (trade name) 5010R5, available from Mitsubishi Engineering-Plastics Corporation, P R (O2): 4.67 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), P R (H2O) : 46.1 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), log(P R (H2O) / P R (O2)) = 0.99 POK: Polyketone, “POKETONE” (trade name) M330A, available from Hyosong, P R (O2): 0.7 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), P R (H2O) : 34.0 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), log(P R (H2O) / P R (O2)) = 1.72 Elastomer

[0056] Br-IPMS: brominated isobutylene-p-methylstyrene copolymer, “EXXPRO” (trade name) 3745, available from Exxon Mobil Chemical Corporation, P E (O2): 87 × 10 -12 cm·cm 3 / (cm2 ·s·cmHg), P E (H2O): 18 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), log(P E (H2O) / P E (O2)) = -0.68 SIBS: Styrene-Isobutylene-Styrene Block Copolymer, “SIBSTAR” (trade name) 102T, available from Kaneka Corporation, P E (O2) : 91 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), P E (H2O): 17 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), log(P E (H2O) / P E (O2)) = -0.73 Mah-EP: Maleic anhydride-modified ethylene-propylene copolymer, “TAFMER” (trade name) MP0620, available from Mitsui Chemicals, Inc., P E (O2) : 940 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), P E (H2O): 81.3 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), log(P E (H2O) / P E(O2)) = -1.06 Mah-EB: Maleic anhydride-modified ethylene-1-butene copolymer, “TAFMER” (trade name) MH7010, available from Mitsui Chemicals, Inc., P E (O2) : 990 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), P E (H2O): 83.7 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), log(P E (H2O) / P E (O2)) = -1.07 Mah-EEA: Maleic anhydride-modified ethylene-ethyl acrylate copolymer, “HPR AR201”, available from DuPont-Mitsui Polychemicals Co., Ltd., P E (O2) : 910 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), P E (H2O): 87.0 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), log(P E (H2O) / P E (O2)) = -1.02 Mah-SEBS: Maleic anhydride-modified styrene-ethylene / butylene-styrene block copolymer, “Tuftec” (trade name) M1913, available from Asahi Kasei Corporation, P E (O2): 920 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), PE (H2O) : 91.5 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), log(P E (H2O) / P E (O2)) = -1.00 TPA: Polyamide elastomer, “UBESTA” (trade name) XPA 9063X1, available from Ube Industries, Ltd., P R (O2): 39.3 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), P E (H2O): 70.5 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), log(P E (H2O) / P E (O2)) = 0.25 TPEE: Polyester elastomer, “PELPRENE” (trade name) P40B, available from Toyobo Co., Ltd., P E (O2): 113 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), P E (H2O): 50.3 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg), log(P E (H2O) / P E (O2)) = -0.34 Processing aids

[0057] St-Ca: Calcium stearate, “SC-PG”, available from Sakai Chemical Industry Co., Ltd. St-Mg: Magnesium stearate, “SM-PG”, available from Sakai Chemical Industry Co., Ltd. Networking tools

[0058] ZnO: Zinc oxide, “Zinc Oxide III”, available from Seido Chemical Industry Co., Ltd. aging retardants

[0059] 6PPD: N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine, "SANTOFLEX" (trade name) 6PPD, available from Solutia Inc. Comparative example 1

[0060] A rubber compound (a) was prepared using a Banbury mixer in the proportions listed in Table 1, and a 1.5 mm wall thickness tube was extruded onto a mandrel pre-coated with a release agent. This was used as the inner layer material. A polyester reinforcing yarn was braided onto the inner layer material using a braiding machine, and a rubber compound (b) prepared using a Banbury mixer in the proportions listed in Table 2 was extruded onto the reinforcing yarn. Steam vulcanization was then carried out for 60 minutes at 160 °C, the mandrel was withdrawn, and a tube composed of the inner layer / reinforcing layer / protective layer was produced.

[0061] The manufactured rubber compound and the manufactured rubber hose were measured with respect to their oxygen permeability coefficient and water vapor permeability coefficient. The results are listed in Table 3. Examples 1 to 13 and comparative examples 2 to 6

[0062] The polymer components, in the proportions listed in Tables 3 and 4, were fed into a twin-screw extruder (available from Japan Steel Works, Ltd.). The cylinder temperature was set to approximately 20 °C higher than the melting point of the starting material, which had the highest melting point among the polymer components. The material was then conveyed to a kneading zone with a residence time of approximately 3 to 6 minutes and melt-kneaded. The melt-kneaded product was extruded from a die mounted at the outlet into a strand. The resulting strand was pelletized using a resin pelletizer to obtain a pelletized resin composition. The resulting resin composition was measured with respect to its oxygen permeability coefficient and water vapor permeability coefficient.The measurement results are listed in Tables 3 and 4.

[0063] From the measured oxygen permeability coefficient, the thickness expected to yield a gas permeation rate equivalent to that of a 1.5 mm thick rubber compound in comparison example 1 was calculated for each example and comparison example. A tube with a wall thickness corresponding to the calculated thickness was extruded onto a mandrel. This was used as the inner layer material. A polyester reinforcing yarn was braided onto the inner layer material using a braiding machine. A polyester elastomer was extruded onto the reinforcing yarn using an extruder, and a tube composed of the inner layer / reinforcing layer / protective layer was produced. The manufactured tube was measured with respect to the inner layer mass (weight reduction effect), bending strength (flexibility), and tube moisture permeability.The results were expressed as index values ​​relative to comparison example 1, where comparison example 1 was assigned the value 100, and the results were evaluated as follows.

[0064] Inner layer mass: Lower values ​​indicate better performance. Values ​​of 90 or less indicate a weight reduction. Bending force: Lower values ​​indicate better flexibility. Values ​​of 200 or less indicate handling that causes no problems in use.

[0065] Water vapor permeability: Lower values ​​indicate better performance. Values ​​of 700 or less indicate that a resin hose was effective even when considering weight reduction.

[0066] The results are listed in Tables 3 and 4. Measurement of the oxygen permeability coefficient

[0067] A sample of the resin composition was formed into a layer with an average thickness of 0.2 mm using a single-screw extruder with a 40 mm φ (available from Plana Giba Co., Ltd.) equipped with a 550 mm wide T-die. The barrel and die temperatures were set to the melting point of the sample plus 10 °C (if the sample was a composition, the melting point corresponded to the melting point of the polymer component with the highest melting point in the composition), a cooling roll temperature of 50 °C, and a feed rate of 3 m / min. A sample of the thermoplastic resin was formed into a layer with a thickness of 0.05 mm by setting the same temperature conditions and adjusting the extrusion rate and feed rate.The elastomer and rubber compound were hot-pressed for 10 minutes at a temperature of 180 °C, and a layer with a thickness of 0.5 mm was produced.

[0068] The resulting layer and film were cut out and measured using an OXTRAN1 / 50 available from MOCON at a temperature of 21 °C and a relative humidity of 50%. Measurement of the 10% module

[0069] The layer or film produced during the measurement of the oxygen permeability coefficient was die-cut into a dumbbell shape according to JIS No. 3, and a tensile test was performed according to JIS K6301, "Physical Testing Method for Vulcanized Rubber," at a temperature of 25 °C and a speed of 500 mm / min. A stress at 10% elongation (10% modulus) was determined from the resulting stress-strain curve. Measurement of the water vapor permeability coefficient

[0070] The layer or film produced for measuring the oxygen permeability coefficient was cut out and measured using a water vapor permeation tester available from GTR Tech Corporation at a temperature of 60 °C and a relative humidity of 100%. Measurement of hose moisture permeability

[0071] A desiccant (molecular sieves 3A) was added to a tube, which was left in a 50°C oven for 5 hours. The desiccant volume corresponded to 80% of the tube's internal volume, and the tube was hermetically sealed. The tube was then exposed to an atmosphere at 50°C and 95% relative humidity. The weight of the desiccant was measured every 120 hours up to 400 hours, and the amount of moisture absorbed at equilibrium was determined. Measurement of bending force

[0072] Two hoses, each 45 cm long, were bent along an arc with a predetermined radius of curvature, and the bending force was measured. The radius of curvature ranged from 3 times (3D) to 10 times (10D) the hose's outer diameter. The bending force at a predetermined radius (4D) was determined from a curve generated by plotting the ratio between the resulting bending force and the radius of curvature. The bending force is a measure of flexibility; lower values ​​indicate superior flexibility, and higher values ​​indicate inferior flexibility. [Table 1] Table 1 Raw materials Manufacturer Brand Mass parts Brominated butyl rubber EXXONMOBILE CHEMICAL COMPANYExxon Bromobutyl 2255 100 HAF soot Showa Cabot KKShow Black N330 50 paraffin oil Showa Shell Sekiyu KKMachine Oil 22 10 zinc oxide Seido Chemical Industry Co., Ltd.Zinc Oxide III 3 Stearic acid Nippon Oil & Fats Co., Ltd. Stearic Acid Pearls 1 sulfur Hosoi Chemical Industry Co., Ltd. Oil-treated sulfur 1 Vulcanization accelerator DM Ouchi Shinko Chemical Industrial Co.,Ltd.Dibenzothiazyl disulfide NOCCELER DM 2 [Table 2] Table 2 Raw materials Manufacturer Brand Mass parts Ethylene / propylene copolymer rubber Mitsui Chemicals, Inc.Mitsui EPT4070 100 FEF soot NIPPON STEEL Carbon Co., Ltd.HTC #100 80 paraffin oil Showa Shell Sekiyu KKMachine Oil 22 20 zinc oxide Seido Chemical Industry Co., Ltd.Zinc Oxide III 5 Stearic acid Nippon Oil & Fats Co., Ltd. Stearic acid pearls 1 sulfur Hosoi Chemical Industry Co., Ltd. Oil-treated sulfur 1 Vulcanization accelerator CZ Ouchi Shinko Chemical Industrial Co.,Ltd.N-Cyclohexyl-2-benzothiazylsulfenamideNOCCELER CZ-G 1 TT vulcanization accelerator Ouchi Shinko Chemical Industrial Co.,Ltd.Tetramethylthiuram disulfide NOCCELERTT 1 [Table 3] Table 3-I Comparative example 1 Comparative example 2 Example 1 Example 2 Comparative example 3 Thermoplastic resin Ny6 Mass parts 60 28 20 Ny6 / 12 Mass parts 12 Ny11 Mass parts 40 Ny12 Mass parts 20 EVOH-1 Mass parts EVOH-2 Mass parts PBT Mass parts POK Mass parts Elastomer Br-IPMS Mass parts 40 60 60 60 SIBS Mass parts Mah-EP Mass parts Mah-EB Mass parts Mah-EEA Mass parts Mah-SEBS Mass parts TPA Mass parts TPEE Mass parts Processing St-Ca Mass parts 2 2 2 ing aids St-Mg Mass parts Networking tools ZnO Mass parts aging retardants 6PPD Mass parts Oxygen permeability coefficient P(O2) *1) 63,96 7,01 10,81 18,27 48,73 Water vapor permeability coefficient P(H2O) *2) 16,3 68,9 28,7 26,3 20,9 10% module M10 MPa 2 17 5,6 5,4 6,3 P(O2) × M10 127,92 119,09 60,55 98,68 307,02 log(P(H2O2) / P(O2)) -0,59 0,99 0,42 0,16 -0,37 Inner layer thickness mm 1,5 0,5 0,8 1,3 3,5 Inner layer mass 100 33 51 87 232 Bending force 100 283 144 235 730 Hose moisture permeability 100 1079 291 158 47 *1) Unit of the oxygen permeability coefficient P(O2): 10 -12 cm·cm 3 / (cm 2 ·s·cmHg) *2) Unit of the water vapor permeability coefficient P(H2O): 10 -12 cm·cm 3 / (cm 2 ·s·cmHg) Table 3-II Comparative example 4 Example 3 Example 4 Comparative example 5 Example 5 Thermoplastic resin Ny6 Mass parts 30 30 Ny6 / 12 Mass parts 10 10 Ny11 Mass parts Ny12 Mass parts 40 EVOH-1 Mass parts 30 35 EVOH-2 Mass parts PBT Mass parts POK Mass parts Elastomer Br-IPMS Mass parts 60 SIBS Mass parts 60 30 65 Mah-EP Mass parts Mah-EB Mass parts 70 Mah-EEA Mass parts Mah-SEBS Mass parts 30 TPA Mass parts TPEE Mass parts Processing aids St-Ca Mass parts 2 2 2 St-Mg Mass parts 2 2 Networking tools ZnO Mass parts aging retardants 6PPD Mass parts Oxygen permeability coefficient P(O2) *1) 41,12 9,90 10,81 4,11 3,96 Water vapor permeability coefficient P(H2O) *2) 20,1 34,1 38,0 37,2 19,4 10% module M10 MPa 6,5 6,6 7 6,8 6,5 P(O2) × M10 267,27 65,33 75,69 27,96 25,74 log(P(H2O2) / P(O2)) -0,31 0,54 0,55 0,96 0,69 Inner layer thickness mm 2,9 0,7 0,8 0,3 0,3 Inner layer mass 196 47 51 20 19 Bending force 636 155 180 67 61 Hose moisture permeability 54 377 385 991 536 *1) Unit of the oxygen permeability coefficient P(O2): 10 -12 cm·cm 3 / (cm 2 ·s·cmHg) *2) Unit of the water vapor permeability coefficient P(H2O): 10 -12 cm·cm 3 / (cm 2 ·s·cmHg) [Table 4] Table 4-I Example 6 Example 7 Example 8 Example 9 Comparative example 6 Thermoplastic resin Ny6 Mass parts Ny6 / 12 Mass parts Ny11 Mass parts Ny12 Mass parts 50 EVOH-1 Mass parts 35 35 35 EVOH-2 Mass parts 35 PBT Mass parts POK Mass parts Elastomer Br-IPMS Mass parts 35 35 25 SIBS Mass parts 35 55 Mah-EP Mass parts 30 Mah-EB Mass parts Mah-EEA Mass parts 30 Mah-SEBS Mass parts TPA Mass parts 25 TPEE Mass parts 30 10 Processing aids St-Ca Mass parts St-Mg Mass parts 2 2 2 2 2 Networking tools ZnO Mass parts aging retardants 6PPD Mass parts Oxygen permeability coefficient P(O2) *1) 5,33 5,03 5,63 5,18 21,78 Water vapor permeability coefficient P(H2O) *2) 24,8 24,0 24,8 24,8 35,6 10% module M10 MPa 5,4 6,9 5,3 5,7 8,1 P(O2) × M10 28,78 34,68 29,86 29,51 176,40 log(P(H2O) / P(O2)) 0,67 0,68 0,64 0,68 0,21 Inner layer thickness mm 0,4 0,4 0,4 0,4 1,6 Inner layer mass 25 24 27 25 104 Bending force 68 83 71 70 420 Hose moisture permeability 511 525 483 526 180 *1) Unit of the oxygen permeability coefficient P(O2):10 -12 cm·cm 3 / (cm 2 ·s·cmHg) *2) Unit of the water vapor permeability coefficient P(H2O):10 -12 cm·cm 3 / (cm 2 ·s·cmHg) Table 4-II Example 10 Example 11 Example 12 Example 13 Thermoplastic resin Ny6 Mass parts 20 28 Ny6 / 12 Mass parts 12 Ny11 Mass parts Ny12 Mass parts EVOH-1 Mass parts EVOH-2 Mass parts PBT Mass parts 40 POK Mass parts 40 20 Elastomer Br-IPMS Mass parts 60 60 SIBS Mass parts 60 60 Mah-EP Mass parts Mah-EB Mass parts Mah-EEA Mass parts Mah-SEBS Mass parts TPA Mass parts TPEE Mass parts Processing aids St-Ca Mass parts 2 2 2 St-Mg Mass parts 2 Networking tools ZnO Mass parts 3 aging retardants 6PPD Mass parts 1 Oxygen permeability coefficient P(O2) *1) 12,79 9,75 9,44 10,81 Water vapor permeability coefficient P(H2O) *2) 44,9 17,8 21,7 28,7 10% module M10 MPa 8,2 8,2 7,8 5,6 P(O2) × M10 104,90 79,92 73,65 60,55 log(P(H2O2) / P(O2)) 0,55 0,26 0,36 0,42 Inner layer thickness mm 0,9 0,7 0,7 0,8 Inner layer mass 61 46 45 51 Bending force 250 190 175 144 Hose moisture permeability 386 201 252 291 *1) Unit of the oxygen permeability coefficient P(O2):10 -12 cm·cm 3 / (cm 2 ·s·cmHg) *2) Unit of the water vapor permeability coefficient P(H2O):10 -12 cm·cm 3 / (cm 2 ·s·cmHg) Industrial applicability

[0073] The resin composition according to one embodiment of the present invention can be used in a suitable manner for the manufacture of a refrigerant transport hose.

Claims

[1] Resin composition for a refrigerant transport hose, the resin composition comprising: a thermoplastic resin; and an elastomer; wherein the thermoplastic resin and the elastomer form an island-in-the-sea structure consisting of a matrix of the thermoplastic resin and an area of ​​the elastomer, wherein the resin composition includes a P(O2), an M10, and a P(H2O) that satisfy formulas 1 and 2: 0 <P(O2)×M10≤150 and log(P(H2O) / P(O2))≤0.9 , where P(O2) is an oxygen permeability coefficient [cm·cm 3 / (cm 2 ·s·cmHg)] at a temperature of 21 °C and a relative humidity of 50 %, M10 is a 10 % modulus [MPa] at a temperature of 25 °C and P(H2O) is a water vapor permeability coefficient [cm·cm 3 / (cm 2·s·cmHg)] at a temperature of 60 °C and a relative humidity of 100%, wherein the thermoplastic resin is at least one selected from the group consisting of a polyamide resin, a polyester resin, a vinyl alcohol resin and a polyketone resin, wherein the elastomer is at least one selected from the group consisting of a butyl rubber, a modified butyl rubber, an olefin thermoplastic elastomer, a styrene-based thermoplastic elastomer, a polyamide elastomer and a polyester elastomer, wherein the resin composition comprises at least one processing aid selected from the group consisting of a fatty acid, a fatty acid metal salt, a fatty acid ester and a fatty acid amide. [2] Resin composition for a refrigerant transport hose according to claim 1, wherein the water vapor permeability coefficient P(H2O) at a temperature of 60 °C and a relative humidity of 100 % is 60 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg) or less. [3] Resin composition for a refrigerant transport hose according to claim 1 or 2, wherein the oxygen permeability coefficient P(O2) at a temperature of 21 °C and a relative humidity of 50 % is 20 × 10 -12 cm·cm 3 / (cm 2 ·s·cmHg) or less. [4] Resin composition for a refrigerant transport hose according to any one of claims 1 to 3, wherein the 10% modulus M10 is 10 MPa or less at a temperature of 25 °C. [5] Resin composition for a refrigerant transport hose according to any one of claims 1 to 4, wherein an oxygen permeability coefficient P R (O2) [cm·cm 3 / (cm 2 ·s·cmHg)] of the thermoplastic resin at a temperature of 21 °C and a relative humidity of 50 % and a water vapor permeability coefficient P R (H2O) [cm·cm 3 / (cm 2 ·s·cmHg)] of the thermoplastic resin at a temperature of 60 °C and a relative humidity of 100 % must meet formula 3: log(PR(H2O) / PR(O2))≤5.0 . [6] Resin composition for a refrigerant transport hose according to any one of claims 1 to 5, wherein an oxygen permeability coefficient P R (O2) [cm·cm 3 / (cm 2 ·s·cmHg)] of the elastomer at a temperature of 21 °C and a relative humidity of 50 % and a water vapor permeability coefficient P R (H2O) [cm·cm 3 / (cm 2 ·s·cmHg)] of the elastomer at a temperature of 60 °C and a relative humidity of 100 % must meet formula 4: log(PE(H2O) / PE(O2))≤1.5 . [7] Refrigerant transport hose comprising a layer of the resin composition according to any one of claims 1 to 6.