Refrigerant transport hose and method for its manufacture

Abstract

Refrigerant transport hose (1) comprising: an outer layer (4); a reinforcing layer (3); and an inner layer (2); wherein the outer layer (4) consists of a resin composition comprising an elastomer with a polyisobutylene backbone and cross-linked resin, wherein the content of the elastomer with a polyisobutylene backbone in the resin composition is 30% by mass or more and 90% by mass or less, based on the mass of the resin composition, wherein the content of the cross-linked resin in the resin composition is 10% by mass or more and 70% by mass or less, based on the mass of the resin composition, where the water vapor permeability of the resin composition is 2.0 g·mm / (m²). 2 ·24h) or less, and the ratio TB 100 / TB 25 the breaking strength TB 100the resin composition at 100 °C corresponds to the breaking strength TB 25 The resin composition at 25 °C is 0.2 to 1.0.

Description

Technical field

[0001] The present invention relates to a refrigerant transport hose and a method for its manufacture. The present invention relates in particular to a refrigerant transport hose for use in an air conditioning system of a car and a method for manufacturing the refrigerant transport hose. State of the art

[0002] Given the increasing demand for weight reduction in cars, efforts have been made to achieve this by manufacturing a hose for automotive use that is not made of rubber, but instead uses a resin with high barrier properties to reduce its thickness. In particular, refrigerant transport hoses for current automotive air conditioning systems are primarily made of rubber. If the main material can be replaced with a resin with high barrier properties, a weight reduction can be achieved.

[0003] JP H04 - 145 284 A (Patent Document 1) describes a hose for transporting a refrigerant such as Freon gas. The outer tube of the hose is made of a thermoplastic elastomer consisting of thermoplastic polyolefin resin and EPDM or butyl rubber. JP S61 - 140 691 A (Patent Document 2) describes a pipe for hot water circulation for use in a heating system. The pipe consists of a laminate of a saponified substance fBl layer / ribbed layer or a water-crosslinked polyolefin iCl layer of a saponified substance fBl / ethylene-vinyl acetate copolymer or a water-crosslinked polyolefin iC1 layer. JP 2001 - 235 068 A (Patent Document 3) describes a hose with an inner tube and a reinforcing layer attached to the circumference of the inner tube.The inner tube has an inner layer, a barrier layer which is attached to the circumference of the inner layer via a so-called hotmelt layer, and an outer layer which is attached to the circumference of the barrier layer via a hotmelt layer. List of literature on patent literature Patent document 1: JP H04 - 145 284 A Patent document 2: JP S61 - 140 691 A Patent document 3: JP 2001 - 235 068 A Brief description of the invention: Technical problem

[0004] A car's air conditioning system, and similar systems, are installed in a confined, tight space within the vehicle. Therefore, the refrigerant hose must be highly flexible and allow for easy installation, even in tight spaces. Water vapor penetrating the hose from the outside causes moisture inside the air conditioner to freeze; consequently, the material used for the outer tube of a refrigerant hose must have excellent barrier properties against water vapor. Furthermore, the refrigerant hose must be durable enough to withstand long-term use in the high-temperature, high-humidity environment of an engine compartment.

[0005] However, since the outer tube of a resin hose described in patent document 1 consists of thermoplastic elastomer containing thermoplastic polyolefin resin, the heat resistance is not necessarily sufficient.

[0006] One object of the present invention is to provide a refrigerant transport hose that has excellent flexibility, excellent barrier properties for water vapor and excellent heat resistance. Solution to the problem

[0007] One embodiment of the present invention (I) is a refrigerant transport hose comprising an outer layer, a reinforcing layer, and an inner layer. The outer layer consists of a resin composition containing an elastomer with a polyisobutylene backbone and cross-linked resin. The content of the elastomer with a polyisobutylene backbone in the resin composition is 30% or more and 90% or less by mass, based on the mass of the resin composition. The content of the cross-linked resin in the resin composition is 10% or more and 70% or less by mass, based on the mass of the resin composition. The water vapor permeability of the resin composition is 2.0 g / mm² / m². 2 ·24h) or less. The ratio TB 100 / TB 25 the breaking strength TB 100 the resin composition at 100 °C corresponds to the breaking strength TB 25 The resin composition at 25 °C is 0.2 to 1.0.

[0008] One embodiment of the present invention (II) is a method for producing the refrigerant transport hose of the embodiment of the present invention (I). The method includes: producing a composition for an outer layer by melt kneading an elastomer with a polyisobutylene backbone and a crosslinkable resin; and forming an outer layer by adding a silanol condensation catalyst to the composition for an outer layer during hose extrusion forming and extrusion forming of a composition to which a silanol condensation catalyst is added.

[0009] The present invention includes the following embodiments. [1] A refrigerant transport hose that includes an outer layer, a reinforcing layer and an inner layer. The outer layer of the hose consists of a resin composition containing an elastomer with a polyisobutylene backbone and cross-linked resin. wherein the content of the elastomer with a polyisobutylene backbone in the resin composition is 30 wt% or more and 90 wt% or less based on a mass of the resin composition, a content of the cross-linked resin in the resin composition of 10% by mass or more and 70% by mass or less, based on the mass of the resin composition, a water vapor permeability of the resin composition of 2.0 g·mm / (m²) 2 ·24h) or less, and a ratio TB 100 / TB 25 a breaking strength TB 100 the resin composition at 100 °C to a breaking strength TB 25 The resin composition at 25 °C is 0.2 to 1.0. [2] The refrigerant transport hose according to [1], wherein the cross-linked resin is a cross-linked silane-modified resin obtained by modifying a thermoplastic resin with a silane compound. [3] The refrigerant transport hose according to [2], wherein the cross-linked resin is cross-linked silane-modified polyolefin obtained by modifying polyolefin with a silane compound. [4] The refrigerant transport hose according to [3], wherein the cross-linked resin is cross-linked silane-modified polypropylene obtained by modifying polypropylene with a silane compound. [5] The refrigerant transport hose according to one of points [1] to [4], wherein the elastomer with a polyisobutylene backbone is butyl rubber or modified butyl rubber and the elastomer with a polyisobutylene backbone is dynamically crosslinked. [6] The refrigerant transport hose according to one of points [1] to [5], wherein the resin composition contains 1 mass % or more and 4 mass % or less of an aging retarder based on the mass of the resin composition. [7] The refrigerant transport hose according to one of points [1] to [6], wherein the inner layer consists of a thermoplastic resin composition, the thermoplastic resin composition has an islands-in-the-sea structure in which elastomer is present as a domain in a matrix containing the thermoplastic resin, the thermoplastic resin contains 50% or more by mass and 100% or less by mass of polyamide, based on the mass of the thermoplastic resin, the elastomer contains the elastomer with a polyisobutylene backbone, a content of the elastomer of 30% by mass or more and 80% by mass or less, based on the mass of the thermoplastic resin composition, and The thermoplastic resin composition also contains an aging retarder based on phenylenediamine or quinoline and a processing aid. [8] The refrigerant transport hose according to one of points [1] to [7], wherein the reinforcement layer contains a polyester fiber, a polyamide fiber, an aramid fiber, a PBO fiber (poly-p-phenylene-benzobisoxazole fiber), a vinylon fiber or a rayon fiber. [9] A method for manufacturing the refrigerant transport hose according to one of points [1] to [8]. The process includes: producing an outer layer composition by melt kneading an elastomer with a polyisobutylene backbone and a crosslinkable resin; and forming an outer layer by adding a silanol condensation catalyst to the outer layer composition during tube extrusion forming and extrusion forming of a composition to which the silanol condensation catalyst is added.

[10] The method according to [9], wherein the crosslinkable resin is a silane-modified resin obtained by modifying a thermoplastic resin with a silane compound. Advantageous effects of the invention

[0010] The refrigerant transport hose of an embodiment of the present invention has excellent flexibility, barrier properties for water vapor and heat resistance. Brief description of the drawings Fig.Figure 1 is a cross-sectional view of a refrigerant transport hose. Fig. Figure 2 is a diagram illustrating an evaluation procedure for the flexibility of a hose. Description of embodiments

[0011] One embodiment of the present invention (I) relates to a refrigerant transport hose.

[0012] The refrigerant transport hose is referred to as a refrigerant transport hose for an air conditioning system or the like. The refrigerant transport hose of an embodiment of the present invention is used in a particularly suitable manner as a refrigerant transport hose for an automotive air conditioning system. Examples of air conditioning refrigerants include fluorocarbons (HFCs), hydrofluoroolefins (HFOs), hydrocarbons, carbon dioxide, ammonia, and water. 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.

[0013] The refrigerant transport hose of an embodiment of the present invention includes an outer layer, a reinforcing layer and an inner layer.

[0014] Fig. Figure 1 is a cross-sectional view of a refrigerant transport hose according to one embodiment of the present invention. However, one embodiment of the present invention is not limited to the illustration in Figure 1. Fig. 1 limited.

[0015] The refrigerant transport hose 1 includes an inner layer 2, a reinforcement layer 3 arranged on the outside of the inner layer 2, and an outer layer 4 arranged on the outside of the reinforcement layer 3.

[0016] The outer layer consists of a resin composition containing an elastomer with a polyisobutylene backbone and cross-linked resin.

[0017] The elastomer with a polyisobutylene backbone is not restricted as long as the elastomer has a polyisobutylene backbone, but is preferably a butyl rubber (IIR), a modified butyl rubber or a styrene-isobutylene-styrene block copolymer, and is more preferably a butyl rubber or a modified butyl rubber.

[0018] The polyisobutylene backbone refers to a chemical structure formed by the polymerization of a variety of isobutylenes, i.e., a chemical structure formed by -[-CH2-C(CH3)2-] n - is represented (where n is an integer of 2 or greater).

[0019] Butyl rubber is an isobutylene-isoprene copolymer obtained by copolymerization of isobutylene and a small amount of isoprene, and is abbreviated as IIR.

[0020] The modified butyl rubber is a butyl rubber in which a double bond, a halogen, and the like are present in an isoprene backbone. A halogenated butyl rubber is preferred as the modified butyl rubber, a brominated butyl rubber and a chlorinated butyl rubber are more preferred, and a brominated butyl rubber is preferred even more.

[0021] A styrene-isobutylene-styrene block copolymer is abbreviated SIBS.

[0022] Since the resin composition contains the elastomer with a polyisobutylene backbone, the flexibility and barrier properties for water vapor of the resin composition are improved.

[0023] The elastomer with a polyisobutylene backbone is preferably dynamically crosslinked. Dynamic crosslinking improves durability.

[0024] The content of the elastomer with a polyisobutylene backbone is 30% or more by weight and 90% or less by weight, preferably 40% or more by weight and 89% or less by weight, and more preferably 50% or more by weight and 88% or less by weight, based on the mass of the resin composition. If the content of the elastomer with a polyisobutylene backbone is too low, flexibility cannot be guaranteed. If the content is too high, extrudability deteriorates.

[0025] The resin composition contains a cross-linked resin. The resin composition achieves excellent heat resistance due to the presence of a cross-linked resin.

[0026] The crosslinked resin is a resin that is crosslinked. The crosslinked resin is not limited, but is preferably a crosslinked resin to which a silane-modified resin is crosslinked. The silane-modified resin is a resin obtained by modifying a thermoplastic resin with a silane compound. The silane-modified resin is preferably a resin obtained by modifying a polyolefin-based thermoplastic resin with a silane compound, and more preferably a crosslinkable resin with a hydrolyzable silyl group (preferably an alkoxysilyl group) obtained by modifying a polyolefin-based thermoplastic resin with a silane compound.That is, the cross-linked resin is preferably a cross-linked, silane-modified resin obtained by modifying a thermoplastic resin with a silane compound, more preferably a cross-linked, silane-modified polyolefin obtained by modifying a polyolefin with a silane compound, and even more preferably a cross-linked, silane-modified polypropylene obtained by modifying a polypropylene with a silane compound.

[0027] The silane compound is not restricted, but is preferably a compound represented by formula (1). R 1 -SiR 2 n Y 3-n (1)

[0028] R 1 is an ethylene unsaturated hydrocarbon group, R 2 is a hydrocarbon group, Y is a hydrolyzable organic group, and n is an integer from 0 to 2.

[0029] R 1is preferably an ethylene unsaturated hydrocarbon group having a carbon number of 2 to 10, and examples include a vinyl group, a propenyl group, a butenyl group, a cyclohexenyl group and a γ-(meth)acryloyloxypropyl group.

[0030] R 2 is preferably a hydrocarbon group with a carbon number of 1 to 10, and examples include a methyl group, an ethyl group, a propyl group, a decyl group and a phenyl group.

[0031] Y is preferably a hydrolyzable organic group having a carbon number of 1 to 10, and examples include a methoxy group, an ethoxy group, a formyloxy group, an acetoxy group, a propionyloxy group, an alkylamino group and an arylamino group.

[0032] Specific examples of the silane compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, and γ-methacryloyloxypropyltrimethoxysilane. Of these, vinyltrimethoxysilane is preferred.

[0033] The polyolefin-based thermoplastic resin from which the silane-modified resin is composed is not restricted, and examples include polyethylene, a copolymer of ethylene and α-olefin, polypropylene, and a copolymer of propylene and another α-olefin. Polypropylene and a copolymer of propylene and another α-olefin are preferred, and polypropylene is particularly preferred.

[0034] The hydrolyzable silyl group refers to a group that, upon hydrolysis, produces a silanol group (=Si-OH) and is preferably a group represented by formula (2). SiR 2 n Y 3-n (2)

[0035] R 2However, Y and Y have the same meaning as described above.

[0036] Crosslinkable resin is resin that can undergo a crosslinking reaction but is not yet crosslinked. The type of crosslinking reaction is not restricted and can be peroxide crosslinking, but moisture crosslinking (water crosslinking) is preferred.

[0037] The process for modifying with a silane compound is not restricted, and examples include grafting and copolymerization. Grafting is a process in which a silane compound is added to a resin by a grafting reaction; more precisely, it is a reaction in which a carbon radical is generated by cleavage of a carbon-hydrogen bond of polyolefin, and a silane compound with an ethylene unsaturated hydrocarbon group is added to the carbon radical. The modification can preferably be carried out by melt kneading of resin and a silane compound of formula (1) in the presence of a radical initiator, such as an organic peroxide. The copolymerization can preferably be carried out by radical copolymerization of a resin-forming monomer and a silane compound of formula (1).

[0038] The silane-modified resin is preferably a silane-modified polypropylene. The silane-modified resin is commercially available, and a commercially available product can be used as the silane-modified resin employed in an embodiment of the present invention. Examples of commercially available silane-modified resin products include "Linklon" (brand name), available from Mitsubishi Chemical Corporation.

[0039] The content of the cross-linked resin is 10% by mass or more and 70% by mass or less, preferably 11% by mass or more and 60% by mass or less, and more preferably 12% by mass or more and 50% by mass or less, based on the mass of the resin composition. If the content of the cross-linked resin is too low, extrudability deteriorates. If the content is too high, flexibility is lost.

[0040] The resin composition can contain resins other than the cross-linked resin. Examples of resins other than the cross-linked resin include polyolefin resin and polyamide resin. Examples of polyolefin resins include polypropylene. Mixing polypropylene with the cross-linked resin creates a phase structure that tends to exhibit strength upon heating because the viscosity of the resin component stabilizes. Since polypropylene has good barrier properties against water vapor, the barrier properties of the entire composition are also good against water vapor.

[0041] In a case where the resin composition contains a resin other than the cross-linked resin, the content of the resin other than the cross-linked resin is preferably 1% by mass or more and 60% by mass or less, more preferably 2% by mass or more and 55% by mass or less, and even more preferably 3% by mass or more and 50% by mass or less, based on the mass of the resin composition.

[0042] The water vapor permeability of the resin composition is 2.0 g / mm² / m². 2 ·24h) or less, and preferably 1.9 g·mm / (m 2 ·24h) or less.

[0043] If the water vapor permeability is too high, moisture from the outside air penetrates the refrigerant transport hose and can lead to freezing of moisture inside the air conditioner. One embodiment of the present invention effectively blocks the penetration of moisture from the outside by using a material as the outer layer that is less likely to allow water vapor permeation.

[0044] The water vapor transmission coefficient is defined as follows: The water vapor transmission coefficient is the amount of water vapor that passes through a thickness of 1 mm per 1 m. 2 The surface area is penetrated within 24 hours under specified temperature and humidity conditions. Water vapor permeability is measured at a temperature of 60 °C and a relative humidity of 95% using a water vapor permeability tester.

[0045] The resin composition exhibits a ratio of TB 100 / TB 25 the breaking strength TB 100 at 100 °C to breaking strength TB 25 at 25 °C from 0.2 or more and 1.0 or less, preferably 0.3 or more and 1.0 or less, and more preferably 0.35 or more and 1.0 or less. If the TB 100 / TB 25 When the coefficient is closer to 1.0, better heat resistance is achieved. The use of cross-linked resin reduces the TB (thermal resistance) requirement. 100 / TB 25 into the numerical range described above, and heat resistance is improved.

[0046] The tensile strength can be measured according to the measurement method specified in JIS K 6251 “Rubber, vulcanized or thermoplastics - Determination of tensile stress-strain properties”.

[0047] The resin composition preferably contains a silanol condensation catalyst. The presence of the silanol condensation catalyst promotes the crosslinking of the silane-modified resin during the formation of the crosslinked resin.

[0048] Examples of the silanol condensation catalyst include, but are not limited to, a metal salt of an organic acid, a titanate, a borate, an organic amine, an ammonium salt, a phosphonium salt, an inorganic acid, an organic acid, and an ester of an inorganic acid.

[0049] Examples of the salt of an organic metallic acid include, but are not limited to, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetate, dibutyltin dioctoate, tin(II) acetate, tin(II) octanoate, cobalt naphthenate, lead octylate, lead naphthenate, zinc octylate, zinc caprylate, iron 2-ethylhexanoate, iron octylate and iron stearate.

[0050] Examples of titanate include, but are not limited to, tetrabutyl titanate, tetranonyl titanate, and bis(acetylacetonitrile)-diisopropyl titanate.

[0051] Examples of organic amines include, but are not limited to, ethylamine, dibutylamine, hexylamine, triethanolamine, dimethyl soyamine, tetramethylguanidine, and pyridine.

[0052] Examples of the ammonium salt include, but are not limited to, ammonium carbonate and tetramethylammonium hydroxide. Examples of the phosphonium salt include, but are not limited to, tetramethylphosphonium hydroxide.

[0053] Examples of inorganic acids include, but are not limited to, sulfuric acid and hydrochloric acid.

[0054] Examples of organic acids include, but are not limited to, acetic acid, stearic acid, maleic acid, toluenesulfonic acid, and sulfonic acids such as alkylnaphthylsulfonic acid. Examples of inorganic acid esters include, but are not limited to, phosphoric acid esters.

[0055] The silanol condensation catalyst is preferably a salt of an organic metallic acid, a sulfonic acid, or a phosphoric acid ester, and more preferably a metal carboxylate of tin such as dioctyltin dilaurate, alkylnaphthylsulfonic acid, and ethylhexyl phosphate. One type of silanol condensation catalyst can be used alone, or two or more types of silanol condensation catalysts can be combined and used in a suitable manner.

[0056] The content of silanol condensation catalyst is not subject to any special restrictions, but is preferably 0.0001 to 0.5 parts by mass, and more preferably 0.0001 to 0.3 parts by mass, based on 100 parts by mass of the silane-modified resin.

[0057] The silanol condensation catalyst is preferably used as a masterbatch containing a silanol condensation catalyst, in which resin and a silanol condensation catalyst are mixed. Examples of the resin that can be used for this masterbatch containing a silanol condensation catalyst include a polyolefin, with polyethylene, polypropylene, and a copolymer thereof being preferred.

[0058] In a case where the silanol condensation catalyst is used as a masterbatch containing a silanol condensation catalyst, in which resin and a silanol condensation catalyst are mixed, the content of the silanol condensation catalyst in the masterbatch is preferably, but not limited to, 0.1 to 5.0 wt%. A commercially available product, such as "PZ010" from Mitsubishi Chemical Corporation, may be used as the masterbatch containing the silanol condensation catalyst.

[0059] The resin composition preferably contains an aging retarder. The aging retarder improves the extrusion moldability when shaping the resin composition before crosslinking.

[0060] Examples of the aging retardant include, but are not limited to, a hindered phenol-based antioxidant, a phenol-based antioxidant, an amine-based antioxidant, a phosphorus-based heat stabilizer, a metal deactivator, and a sulfur-based heat stabilizer, wherein a hindered phenol-based antioxidant is preferred and a hindered phenol-based antioxidant with a pentaerythritol ester structure is more strongly preferred. Specific examples of the hindered phenol-based antioxidant include IRGANOX (trade name) 1010 (pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]), available from BASF Japan Ltd.

[0061] The content of the aging retarder is preferably 1% by mass or more and 4% by mass or less, and more preferably 1% by mass or more and 3.5% by mass or less, based on the mass of the resin composition.

[0062] The resin composition may contain an elastomer other than the elastomer with a polyisobutylene backbone, a resin other than the silane-modified resin, and an additive other than the silanol condensation catalyst and the aging retarder, in a range that does not impair the effect of the present invention.

[0063] The resin composition can have any desired phase structure, but preferably has an islands-in-the-sea structure or a co-continuous structure, and more preferably an islands-in-the-sea structure consisting of a matrix (sea phase) containing crosslinked resin and a domain (island phase) containing an elastomer with a polyisobutylene backbone dispersed in the matrix, wherein the matrix is ​​crosslinked. Crosslinking of the matrix contributes to heat resistance. In the case of a co-continuous structure, excellent flexibility is achieved.

[0064] The reinforcing layer, which is not restricted, is, for example, a layer of braided fibers.

[0065] The reinforcement layer preferably contains, but is not limited to, a polyester fiber, a polyamide fiber, an aramid fiber, a PBO fiber, a vinylon fiber or a rayon fiber.

[0066] The inner layer preferably consists of, but is not limited to, a thermoplastic resin composition. The thermoplastic resin composition has an islands-in-the-sea structure in which the elastomer is present as a domain within a matrix containing the thermoplastic resin. The thermoplastic resin contains 50% or more and 100% or less by weight of polyamide, based on the mass of the thermoplastic resin. The elastomer comprises an elastomer with a polyisobutylene backbone. The elastomer content is 30% or more by weight and 80% or less by weight, based on the mass of the thermoplastic resin composition. The thermoplastic resin composition further contains an aging retarder based on phenylenediamine or quinoline and a processing aid.

[0067] The thermoplastic resin forming the matrix of the thermoplastic resin composition contains, but is not limited to, preferably 50 wt% or more and 100 wt% or less polyamide, based on the mass of the thermoplastic resin, more preferably 75 wt% or more and 100 wt% or less polyamide, based on the mass of the thermoplastic resin, and even more preferably 95 wt% or more and 100 wt% or less polyamide, based on the mass of the thermoplastic resin.

[0068] If the polyamide content is within the range described above, gas barrier properties can be ensured.

[0069] Examples of polyamide include Nylon 6, Nylon 66, Nylon 11, Nylon 12, Nylon 610, a Nylon 6 / 66 copolymer, a Nylon 6 / 12 copolymer, Nylon 46, Nylon 6T, Nylon 9T and Nylon MXD6, of which Nylon 6 and a Nylon 6 / 12 copolymer are preferred.

[0070] The thermoplastic resin that forms the matrix of the thermoplastic resin composition can contain resins other than polyamide. Examples of resins other than polyamide include polyester, polyvinyl alcohol, and polyketone.

[0071] The elastomer, which forms the domain of the thermoplastic resin composition, contains an elastomer with a polyisobutylene backbone. The elastomer with the polyisobutylene backbone is as described above.

[0072] The elastomer content is preferably 30 wt% or more and 80 wt% or less, more preferably 40 wt% or more and 80 wt% or less, and even more preferably 50 wt% or more and 80 wt% or less, based on the mass of the thermoplastic resin composition. If the elastomer content is within the range described above, the dispersion state of the islands-in-the-sea structure, in which the elastomer is the dominant component, can be ensured, and flexibility and gas barrier properties can be guaranteed.

[0073] The thermoplastic resin composition of the inner layer preferably contains an aging retarder based on phenylenediamine or quinoline. The inclusion of such an aging retarder improves the heat aging resistance.

[0074] The phenylenediamine-based aging retardant refers to an aging retardant whose molecular structure includes an aromatic ring having two secondary amines as substituents, and is preferably at least one type selected from the group consisting of N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine, N-phenyl-N',-(1-methylheptyl)-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N,N'-Di-2-naphthyl-p-phenylenediamine and N,N'-Diphenyl-p-phenylenediamine, and is more preferably N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine.

[0075] The quinoline-based anti-aging agent refers to an anti-aging agent with a quinoline scaffold in the molecular structure and is preferably a 2,2,4-trimethyl-1,2-dihydroquinoline polymer.

[0076] The content of the phenylenediamine-based aging retarder or the quinoline-based aging retarder is preferably 0.1 to 10 wt% and more preferably 0.1 to 5.0 wt%, based on the mass of the thermoplastic resin composition.

[0077] The thermoplastic resin composition of which the inner layer is made preferably contains a processing aid. The processing aid contributes to improving the extrudability of the thermoplastic resin composition.

[0078] The processing aid is not particularly restricted, but is preferably at least one type selected from a fatty acid, a fatty acid methyl salt, a fatty acid ester and a fatty acid amide.

[0079] Examples of fatty acids include stearic acid, palmitic acid, lauric acid, oleic acid and linoleic acid, with stearic acid being preferred.

[0080] Examples of the fatty acid metal salt include calcium stearate, potassium stearate, zinc stearate, magnesium stearate and sodium stearate, with calcium stearate being preferred.

[0081] Examples of fatty acid esters include glycerol monostearate, sorbitan stearate, stearyl stearate, and ethylene glycol distearate.

[0082] Examples of fatty acid amides include stearic acid monoamides, oleic acid monoamides, and ethylene bis-stearic acid amides.

[0083] The content of the processing aid is preferably from 0.2 to 10 wt%, more preferably from 1 to 8 wt% and even more preferably from 1 to 5 wt%, based on the mass of the thermoplastic resin composition.

[0084] The thermoplastic resin composition of the inner layer preferably contains a viscosity stabilizer. The addition of the viscosity stabilizer suppresses an increase in viscosity during extrusion of the thermoplastic resin composition and can effectively reduce the formation of residues, thus improving processability.

[0085] Examples of viscosity stabilizers include a divalent metal oxide, an ammonium salt, and a carboxylate.

[0086] Examples of divalent metal oxides include zinc oxide, magnesium oxide, copper oxide, calcium oxide, and iron oxide. The divalent metal oxide is preferably zinc oxide or magnesium oxide, and more preferably zinc oxide.

[0087] Examples of the ammonium salt include ammonium carbonate, ammonium bicarbonate, ammonium chloride, ammonium bromide, ammonium sulfate, ammonium nitrate, ammonium acetate and alkylammonium.

[0088] Examples of carboxylates include sodium acetate, potassium acetate, zinc acetate, copper acetate, sodium oxalate, ammonium oxalate, calcium oxalate, and iron oxalate.

[0089] Zinc oxide is the most preferred viscosity stabilizer.

[0090] The viscosity stabilizer content is preferably 0.1 to 30 wt%, more preferably 0.5 to 20 wt% and even more preferably 0.5 to 5 wt%, based on the mass of the thermoplastic resin composition.

[0091] Preferably, 50% or more by mass of the viscosity stabilizer is included in the matrix. The addition of 50% or more by mass of the viscosity stabilizer to the matrix suppresses an increase in viscosity during extrusion of the thermoplastic resin composition and can effectively reduce the occurrence of residues, thus improving processability.

[0092] The thermoplastic resin composition that makes up the inner layer may contain various additives in addition to the components described above.

[0093] The process for manufacturing the refrigerant transport hose is not particularly restricted, and the refrigerant transport hose can be manufactured as follows. First, the inner layer is extruded into a tube shape using extrusion dies. Then, a fiber, which serves as a reinforcing layer, is braided onto the tube. Finally, the fiber is covered with an outer layer by extrusion dies.

[0094] The method for manufacturing the refrigerant transport hose of an embodiment of the present invention preferably comprises: producing a composition for an outer layer by melt kneading elastomer with a polyisobutylene backbone and crosslinkable resin; and forming an outer layer by adding a silanol condensation catalyst to the composition for an outer layer during hose extrusion forming and extrusion forming of a composition to which the silanol condensation catalyst is added.

[0095] The production of a composition for an outer layer by melt kneading an elastomer with a polyisobutylene backbone and a crosslinkable resin can in the following simply be referred to as the “melt kneading process”.

[0096] Melt kneading is not restricted, but can be carried out using a kneader, a single-screw or twin-screw extruder or the like.

[0097] The temperature during melt kneading is not restricted as long as melt kneading can be carried out, but is preferably 170 to 240 °C.

[0098] The time for melt kneading is not limited as long as the desired kneadable material can be produced, but is preferably two to ten minutes.

[0099] In the melt kneading process, the elastomer with polyisobutylene backbone and the silane-modified resin, as well as optionally various additives such as an aging retarder, a processing aid and a viscosity stabilizer, are placed in a kneader or the like and melt kneaded.

[0100] However, the silanol condensation catalyst is preferably not added during the melt-kneading process. If the silanol condensation catalyst is added during the melt-kneading process, the crosslinkable resin in the outer layer composition gradually crosslinks when the melt-kneaded outer layer composition comes into contact with atmospheric steam, and forming the outer layer composition after crosslinking is therefore difficult. Therefore, the silanol condensation catalyst is preferably added to the outer layer composition during the forming process.

[0101] The “formation of an outer layer by adding a silanol condensation catalyst to the composition for an outer layer during tube extrusion forming and extrusion forming of a composition to which the silanol condensation catalyst is added” is also referred to below simply as the “outer layer formation process”.

[0102] “During extrusion forming” refers to “at the same time as extrusion forming” or “within 6 hours prior to extrusion forming”.

[0103] Extrusion forming can be carried out using an extruder, but is not limited to this, and is preferably carried out using a twin-screw extruder.

[0104] The silanol condensation catalyst can be added to the composition for an outer layer before the composition is filled into the extruder, the composition for an outer layer and the silanol condensation catalyst can be filled into the extruder simultaneously, or the composition for an outer layer and the silanol condensation catalyst can be filled into separate filling ports of the extruder.

[0105] The silanol condensation catalyst can be added directly to the composition for an outer layer, but is preferably added as a masterbatch containing a silanol condensation catalyst, in which resin and a silanol condensation catalyst are mixed.

[0106] An outer layer is formed by extrusion of the composition to which the silanol condensation catalyst has been added onto an outer surface of the reinforcing layer.

[0107] The conditions for extrusion forming are not subject to any restrictions, as long as the outer layer can be formed.

[0108] The method for manufacturing the refrigerant transport hose of an embodiment of the present invention preferably includes bringing the outer layer into contact with water or water vapor after the outer layer formation process (hereinafter also simply referred to as the "water contact process"). Performing the water contact process improves the heat resistance of the outer layer because the crosslinkable resin in the outer layer crosslinks. Although the crosslinkable resin in the outer layer, formed by the outer layer formation process, gradually crosslinks upon contact with water vapor in the atmosphere to form a crosslinked resin, and the outer layer becomes crosslinked, the water contact process is preferably carried out in a case where rapid crosslinking of the outer layer is desired.

[0109] Examples of methods for contacting water or water vapor include, but are not limited to, a method of soaking in a water bath, a method of spraying with water, and a method of placing the layer in a water vapor-containing atmosphere, although a method of placing the layer in a water vapor-containing atmosphere is preferred. In the method of placing the layer in a water vapor-containing atmosphere, the outer layer is left exposed to air for one minute to one month, preferably one hour to one week, and more preferably one to four days, at a temperature of room temperature to 200 °C, preferably room temperature to 100 °C, and a relative humidity of 30 to 100%, preferably 40 to 90%. More precisely, the outer layer is preferably left exposed to air for 72 hours or longer at a temperature of 25 °C and a relative humidity of 50%.

[0110] In a case where the crosslinkable resin is a silane-modified resin, due to the water contact process, a hydrolyzable silyl group (preferably an alkoxysilyl group) in the silane-modified resin in the outer layer is hydrolyzed to form a silanol group; silanol groups undergo a condensation reaction to form a siloxane bond (Si-O-Si) for crosslinking, and thus a crosslinked outer layer is obtained. Example raw materials

[0111] The starting materials used in the following examples and comparative examples are as follows. Nylon 6: Nylon 6 “UBE Nylon” (brand name) 1011FB, available from Ube Industries, Ltd. Nylon 6 / 12: Nylon 6 / 12 copolymer “UBE Nylon” (brand name) 7024B, available from Ube Industries, Ltd. Polypropylene: Propylene homopolymer “Prime Polypro” (brand name) J108M, available from Prime Polymer Co., Ltd. Crosslinkable polypropylene: Silane-modified polypropylene “Linklon” (brand name) XPM800HM, available from Mitsubishi Chemical Corporation IIR: Butyl rubber “Exxon Butyl” 268, available from ExxonMobil Chemical Co. Br-IIR: Brominated butyl rubber, “Exxon Bromobutyl 2255” available from ExxonMobil Chemical Co. Butyl rubber: Brominated isobutylene-p-methylstyrene copolymer rubber “EXXPRO” (brand name) 3745, available from ExxonMobil Chemical Co. PP / EPDM: PP / EPDM thermoplastic elastomer “Santoprene” (brand name) 111-35, available from ExxonMobil Japan GK Elastomer crosslinking agent-1: Alkylphenol-formaldehyde resin “Hitanol” (brand name) 2501Y, available from Hitachi Chemical Co., Ltd. Elastomer crosslinking agent-2: Zinc oxide III, available from Seido Chemical Industry Co., Ltd. Silanol condensation catalyst: Silane crosslinking masterbatch “Catalyst MB” PZ010, available from Mitsubishi Chemical Corporation Aging retardant-1: Hindered phenol-based antioxidant “IRGANOX” (brand name) 1010, available from BASF Japan Ltd. Aging retardant-2: Phenylenediamine-based aging retardant “SANTOFLEX” (brand name) 6PPD, available from Solutia Inc. (Substance name: N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine) Viscosity stabilizer: Zinc oxide III, available from Seido Chemical Industry Co., Ltd. Processing aid-1: Industrial stearic acid, available from Chiba Fatty Acid Co., Ltd. Processing aid-2: Calcium stearate SC-PG, available from Sakai Chemical Industry Co., Ltd. Production of the resin composition for the outer layer

[0112] Resin compositions for the outer layers A1, A2, A3, and A4 were prepared according to the following procedure. The starting materials, with the exception of the silanol condensation catalyst, were added to a twin-screw extruder (available from The Japan Steel Works, Ltd.) at the mixing ratios shown in Table 1 and kneaded for 3 minutes at 235 °C. The kneaded product was continuously extruded from the extruder in a strand-like form, cooled with water, and then cut with a knife.

[0113] In this way, each of the resin compositions for the outer layers A1, A2, A3, and A4 was obtained in pellet form. For the measurement of water vapor permeability and tensile strength, the silanol condensation catalyst was added during film formation by an extruder. For the production of a refrigerant transport hose, the silanol condensation catalyst was added during extrusion of the resin composition in tube form for an outer layer.

[0114] The resin composition for an outer layer A5 was a commercially available thermoplastic PP / EPDM elastomer “Santoprene” (brand name) 111-35 (thermoplastic elastomer in which the matrix was a polypropylene and the domain was an ethylene-propylene-diene copolymer).

[0115] For each of the resin compositions for the outer layers A1, A2, A3, A4 and A5, the water vapor permeability and the tensile strengths were measured at 25 °C and 100 °C and TB 100 / TB 25 calculated. The measurement results are shown in Table 1. Production of a thermoplastic resin composition for the inner layer

[0116] Next, the starting materials, in the mixing ratios shown in Table 2, were placed in a twin-screw extruder (available from The Japan Steel Works, Ltd.) and kneaded for 3 minutes at 235 °C. The kneaded product was continuously extruded from the extruder in a strand-like form, cooled with water, and then cut with a knife. This yielded each of the thermoplastic resin compositions for the inner layers B1, B2, and B3 in pellet form. Manufacturing of the refrigerant transport hose

[0117] The thermoplastic resin composition for an inner layer was extruded onto a mandrel pre-coated with a release agent through a tube mold of the thickness specified in Table 3. A polyester reinforcing yarn was braided onto the mandrel using a braiding machine. Following this, the resin composition for an outer layer, to which the silanol condensation catalyst had been added, was extruded onto the reinforcing yarn through a tube mold of the thickness specified in Table 3. The mandrel was then removed, resulting in a tube consisting of an inner layer, a reinforcing layer, and an outer layer.

[0118] After the resin composition for an outer layer was cured by leaving the manufactured hose exposed to air for 72 hours or longer at a temperature of 25 °C and a relative humidity of 50%, the refrigerant permeation resistance, moisture permeation resistance, flexibility, and heat resistance were evaluated. The evaluation results are shown in Table 3.

[0119] The measurement and evaluation procedures are as follows. Measurement of water vapor permeability

[0120] A sample of the resin composition for an outer layer, to which the silanol condensation catalyst was added, was formed into a film with an average thickness of 0.2 mm using a single-screw press with a 40 mm diameter (available from Pla Gika Co., Ltd.) equipped with a 550 mm wide T-shaped die. The cylinder and die temperatures were set to 10 °C plus the melting point of the polymer component with the highest melting point in the sample composition, with a cooling roller temperature of 50 °C and a feed rate of 3 m / min. The produced film was left to stand in air for 72 hours or longer at a temperature of 25 °C and a relative humidity of 50%, thus producing a film of the cross-linked resin composition.The obtained foil was cut and measured using a water vapor transfer rate tester available from GTR Tec Corporation at a temperature of 60 °C and a relative humidity of 95%. Measurement of fracture strength

[0121] The film produced during the water vapor permeability measurement, with an average thickness of 0.2 mm, was left in air for 72 hours or longer at a temperature of 25 °C and a relative humidity of 50%, thus producing a film of the cross-linked resin composition. This film was die-cut into a dumbbell shape according to JIS No. 3 and subjected to tensile strength tests at a temperature of 25 °C and a speed of 500 mm / min, and at a temperature of 100 °C and a speed of 500 mm / min, according to the measurement procedure specified in JIS K 6251 "Rubber, vulcanized or thermoplastic - Determination of tensile stress-strain properties". Based on the resulting stress-strain curve, the tensile stress (fracture strength) was determined. The tensile stress at 25 °C was used as the TB (thermal strength). 25and the breaking strength at 100 °C as TB 100 A ratio of TB was determined. 100 / TB 25 calculated. The value for TB 100 / TB 25 is an indicator of heat resistance, and a value for TB 100 / TB 25 A value closer to 1.0 indicates superior heat resistance. Evaluation of refrigerant permeation resistance

[0122] The measurement was performed according to SAE J2064 AUG2015. Each of the test specimens S, with a length of 1.07 m, was filled with 70% ± 3% refrigerant (HFO-1234yf) per 1 cm. 3The internal volume of the test specimen S was filled. This test specimen S was left in an atmosphere at 80 °C for 25 days, and the amount of mass reduction (amount of refrigerant permeation) per day [kg / day] was measured for a predetermined period (five to seven days) at the end of the 25-day period. A numerical value obtained by dividing this amount of reduction by an internal surface area of ​​the test specimen S was converted into a numerical value per year to determine a refrigerant permeation coefficient [kg / (m²)]. 2·year)] to calculate. A smaller numerical value of the refrigerant permeation coefficient indicates better refrigerant permeation resistance. A case where this numerical value is 3 or less can be considered to have sufficient refrigerant permeation resistance for practical use. In Table 3, a case where this numerical value was 3 or less was indicated as O, and a case where this numerical value was greater than 3 was indicated as ×. Assessment of moisture permeation resistance

[0123] Each of the test specimens S, which had been left in an oven at 50°C for 5 hours, was filled with a desiccant in a volume corresponding to 80% of the internal volume of the test specimen S and then sealed. The test specimen S was then left in an atmosphere at a temperature of 50°C and a relative humidity of 95%. The mass of the desiccant was measured after 120 hours and after 360 hours, and the increase in the mass of the desiccant between 120 hours and 360 hours was calculated. The extent of the mass increase during the 240-hour period was divided by the internal surface area of ​​the test specimen S, and the water vapor transmission coefficient [mg / (240 h·cm²)] was determined. 2The water vapor transmission coefficient was calculated. A smaller value indicates superior moisture permeation resistance. A value of 3 or less can be considered sufficient for practical use. In Table 1, a value of 3 or less was indicated as O, and a value greater than 3 was indicated as ×. Assessment of flexibility

[0124] As in Fig.As illustrated in Figure 2, one end section of each test specimen S was fastened longitudinally using a fastening tool, such as a clamp. A spring scale was attached to the other end section, which was positioned a predetermined length L (120 + hose outer diameter / 2) × n [mm] away from the fastening point. The test specimen S was then bent in a semicircular arc from a state illustrated by dashed lines to a state illustrated by solid lines. The tensile force F, measured with a spring scale and applied horizontally in the bent state with a radius R on the inner side of the hose of 120 mm, was then used as an indicator for evaluation. A lower value of this tensile force F indicates easy bendability and superior flexibility of the test specimen S.A case where this tensile force F was 20 N or less can be considered to have sufficient flexibility for practical use. In Table 3, a case where this tensile force F was 20 N or less was indicated as O, and a case where this tensile force F was more than 20 N was indicated as ×. Heat resistance rating

[0125] The sealing properties of the die-forged part after heat aging were confirmed by an airtightness test in which the test specimen S was placed in a furnace at 150 °C for 168 hours, pressurized to an internal pressure of 3.5 MPa, and held for five minutes. A case in which no leak occurred was indicated with ◯, and a case in which a leak occurred was indicated with ×. Table 1 Table 1 Proportion of resin composition for the outer layer A1 A2 A3 A4 A5 Crosslinkable polypropylene Mass parts 47 27 13 Polypropylen Mass parts 13 31 IIR Mass parts 48 68 68 Br-IIR Mass parts 67 PP / EPDM Mass parts 100 Elastomer crosslinking agent-1 Mass parts 1 1 1 Elastomer crosslinking agent-2 Mass parts 2 Silanol condensation catalyst Mass parts 2 1 2 Age retardant-1 Mass parts 2 3 3 In total Mass parts 100 100 100 100 100 Water vapor permeability g·mm / (m 2 ·24h) 1,5 1,8 1,5 1,7 14,1 TB 100 / TB 25 0,42 0,42 0,38 0,15 0,47 Table 2 Table 2 Proportion of thermoplastic resin composition for the inner layer B1 B2 B3 Nylon 6 Mass parts 59 40 30 Nylon 6 / 12 Mass parts 5 Butyl-based rubber Mass parts 35 54 59 Age retardant-2 Mass parts 1,5 1,5 1,5 Viscosity stabilizer Mass parts 3,0 3,0 3,0 Processing aid-1 Mass parts 0,7 0,7 0,7 Processing aids-2 Mass parts 0,8 0,8 0,8 In total Mass parts 100 100 100 Table 3-I Table 3 Configuration and evaluation of the hose Example 1 Example 2 Example 3 Example 4 composition B3 B3 B3 B1 inner layer Layer thickness mm 0,8 0,8 0,8 0,8 Reinforcing layer material polyester polyester polyester polyester Layer thickness mm 1,0 0,5 0,5 0,5 angle of inclination ° 55 55 55 55 structure spiral spiral spiral spiral Number of layers 2 1 1 1 outer layer composition A1 A2 A3 A1 Layer thickness mm 0,6 1,6 1,6 1,6 Evaluation Refrigerant permeation resistance ◯ ◯ ◯ ◯ Moisture permeation resistance ◯ ◯ ◯ ◯ flexibility ◯ ◯ ◯ ◯ Heat resistance ◯ ◯ ◯ ◯ Table 3-II Table 3 Configuration and evaluation of the hose Example 5 Example 6 Comparative example 1 Comparison example 2 inner layer composition B2 B3 B3 B3 Layer thickness mm 0,8 0,8 0,8 0,8 Reinforcement layer material polyester polyester polyester polyester Layer thickness mm 0,5 0,5 0,5 0,5 angle of inclination ° 55 55 55 55 structure spiral Braided spiral spiral Number of layers 1 1 1 1 outer layer composition A2 A1 A4 A5 Layer thickness mm 1,6 0,6 0,6 1,6 Evaluation Refrigerant permeation resistance ◯ ◯ ◯ ◯ Moisture permeation resistance ◯ ◯ ◯ × flexibility ◯ ◯ ◯ ◯ Heat resistance ◯ ◯ × ◯ Industrial applicability

[0126] The refrigerant transport hose according to an embodiment of the present invention can be used in a suitable manner for transporting a refrigerant for an air conditioning system and the like of a car and the like. List of reference symbols 1 refrigerant transport hose 2 inner layer 3 Reinforcing layer 4 Outer layer F tractive force L Specified length R hose inner radius S examinee

Claims

[1] Refrigerant transport hose (1) comprising: an outer layer (4); a reinforcing layer (3); and an inner layer (2); wherein the outer layer (4) consists of a resin composition comprising an elastomer with a polyisobutylene backbone and cross-linked resin, wherein the content of the elastomer with a polyisobutylene backbone in the resin composition is 30% by mass or more and 90% by mass or less, based on the mass of the resin composition, wherein the content of the cross-linked resin in the resin composition is 10% by mass or more and 70% by mass or less, based on the mass of the resin composition, where the water vapor permeability of the resin composition is 2.0 g·mm / (m²). 2 ·24h) or less, and the ratio TB 100 / TB 25 the breaking strength TB 100the resin composition at 100 °C corresponds to the breaking strength TB 25 The resin composition at 25 °C is 0.2 to 1.

0. [2] Refrigerant transport hose (1) according to claim 1, wherein the cross-linked resin is a cross-linked, silane-modified resin obtained by modifying thermoplastic resin with a silane compound. [3] Refrigerant transport hose (1) according to claim 2, wherein the cross-linked resin is cross-linked silane-modified polyolefin obtained by modifying polyolefin with a silane compound. [4] Refrigerant transport hose (1) according to claim 3, wherein the cross-linked resin is cross-linked silane-modified polypropylene obtained by modifying polypropylene with a silane compound. [5] Hose (1) for use in refrigerant transport according to any one of claims 1 to 4, wherein The elastomer with a polyisobutylene backbone is butyl rubber or modified butyl rubber, and The elastomer is dynamically cross-linked with a polyisobutylene backbone. [6] Refrigerant transport hose (1) according to any one of claims 1 to 5, wherein the resin composition contains 1 mass % or more and 4 mass % or less of an aging retarder based on the mass of the resin composition. [7] Refrigerant transport hose (1) according to any one of claims 1 to 6, where the inner layer (2) consists of a thermoplastic resin composition, the thermoplastic resin composition has an islands-in-the-sea structure in which the elastomer exists as a domain in a matrix containing the thermoplastic resin, the thermoplastic resin contains 50% or more by mass and 100% or less by mass of polyamide, based on the mass of the thermoplastic resin, the elastomer contains the elastomer with a polyisobutylene backbone, a content of the elastomer of 30% by mass or more and 80% by mass or less, based on the mass of the thermoplastic resin composition, and The thermoplastic resin composition also contains an aging retarder based on phenylenediamine or quinoline and a processing aid. [8] Refrigerant transport hose (1) according to any one of claims 1 to 7, wherein the reinforcement layer (3) comprises a polyester fiber, a polyamide fiber, an aramid fiber, a poly-p-phenylene-benzobisoxazole fiber, a vinylon fiber or a rayon fiber. [9] Method for manufacturing the refrigerant transport hose (1) according to any one of claims 1 to 8, the method comprising: Producing a composition for the outer layer (4) by melt kneading an elastomer with a polyisobutylene backbone and a crosslinkable resin; and Formation of the outer layer (4) by adding a silanol condensation catalyst to the composition for the outer layer (4) during tube extrusion forming and Extrusion shapes of a composition to which the silanol condensation catalyst is added. [10] Method according to claim 9, wherein the crosslinkable resin is a silane-modified resin obtained by modifying a thermoplastic resin with a silane compound.

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