JP2012145180A - Refrigerant transportation hose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerant transportation hose which is excellent in acid resistance and capable of suppressing a crack of the hose to achieve excellent bending durability.SOLUTION: The refrigerant transportation hose includes a tubular inner layer 1 in contact with a fluorine based refrigerant, an intermediate layer 2 formed on an outer circumferential surface thereof, and at least one rubber layer 3, 5 formed on an outer circumference thereof, the inner layer 1 is made from an inner layer material containing polypropylene as the main component, the intermediate layer 2 is made from an intermediate layer material containing polyamide as the main component, and the inner layer material contains an acid acceptor.

Description

  The present invention relates to a refrigerant transport hose such as an air conditioner hose, and more specifically, fluorine such as Freon (R12) and alternative Freon (R-134a, which is a single refrigerant, Fluid H, which is a mixed refrigerant, etc.). The present invention relates to a refrigerant transport hose that can transport a system refrigerant and is used as a piping hose or the like in an engine room of an automobile.

  In general, in a refrigerant transport hose used as a piping hose in an engine room of an automobile, a fluorine-based refrigerant such as Freon (R12) or alternative Freon (R-134a) is used. In recent years, with the tightening regulation of ozone layer depleting gas, requirements for refrigerant permeability of refrigerant hoses for automobiles have become strict. Therefore, the inner layer material of refrigerant transport hoses has high crystallinity such as polyamide. Resin is used. As such a refrigerant transport hose, for example, a hose is proposed that includes an inner layer made of polyamide and an outer layer made of an alloy of polypropylene and butyl rubber, and the two layers are bonded with an adhesive (for example, , See Patent Document 1).

  By the way, since fluorine-based refrigerants such as Freon deteriorate due to long-term use and acid is generated, and the amide bond of polyamide is decomposed by the acid, in the hose described in Patent Document 1, the hose is bent. There are difficulties such as breaking the hose. Therefore, in order to solve this problem, there has been proposed a hose in which a layer (innermost layer) made of polypropylene having better acid resistance than polyamide is formed inside a layer made of polyamide (for example, Patent Documents 2 and 3). reference).

International Publication No. 97/31212 Special table 2008-507436 gazette JP 2002-213659 A

  However, in recent years, refrigerant transport hoses used in automobile engine rooms and the like tend to be used under higher temperature conditions in order to increase cooling efficiency, and decomposition of amide bonds is more easily promoted. Yes. For this reason, the hoses disclosed in Patent Documents 2 and 3 cannot eliminate hose cracks when the hose is bent, and need to be further improved in terms of bending durability.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a refrigerant transport hose that has excellent acid resistance, can suppress cracking of the hose, and has excellent bending durability.

  In order to achieve the above object, a refrigerant transport hose according to the present invention includes a tubular inner layer in contact with a fluorine-based refrigerant, an intermediate layer formed on the outer peripheral surface thereof, and at least one rubber layer formed on the outer periphery thereof. The inner layer is made of an inner layer material containing polypropylene as a main component and containing an acid acceptor, and the intermediate layer is made of an intermediate layer material containing polyamide as a main component. Take the configuration.

  That is, the present inventors have made extensive studies to obtain a refrigerant transport hose that is excellent in acid resistance, can suppress cracking of the hose, and has excellent bending durability. Then, when an inner layer (innermost layer) made of polypropylene having better acid resistance than polyamide is formed on the inner peripheral surface of the layer made of polyamide (intermediate layer) and an acid acceptor is contained in the inner layer, The inventors have found that the object can be achieved and have reached the present invention.

  As described above, in the refrigerant transport hose of the present invention, the intermediate layer made of the intermediate layer material mainly composed of polyamide is formed on the outer peripheral surface of the inner layer composed of the inner layer material mainly composed of polypropylene. Since the acid acceptor is contained in the inner layer, hose breakage due to decomposition of the amide bond can be suppressed, and the bending durability is excellent.

  When the acid acceptor is at least one selected from the group consisting of hydrotalcite, zinc oxide and magnesium oxide, the acid accepting effect is improved.

  Furthermore, when the content of the acid acceptor is in the range of 0.5 to 5 parts by weight with respect to 100 parts by weight of polypropylene, an adverse effect on the intermediate layer (polyamide resin layer) due to the generated acid is suppressed. As a result, the bending durability is further improved, and the reliability of the hose is improved.

  If the inner layer material polypropylene is maleic anhydride-modified polypropylene, the interlayer adhesion between the inner layer and the intermediate layer is improved, and the inner layer and the intermediate layer are directly bonded without an adhesive (adhesive-less). Will be able to.

  When the rubber layer is a butyl rubber layer, the water barrier property (water barrier property) is further improved, and when the rubber layer is an ethylene-propylene rubber layer, the heat resistance is further improved. To do.

It is a perspective view which shows schematic structure of the hose for refrigerant | coolant transportation of this invention.

  Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to this embodiment.

  As the refrigerant transport hose of the present invention, for example, as shown in FIG. 1, an intermediate layer 2 is formed on the outer peripheral surface of the inner layer 1, an inner rubber layer 3 is formed on the outer peripheral surface, and a reinforcing layer is formed on the outer peripheral surface. 4 is formed, and the outer rubber layer 5 is further formed on the outer peripheral surface thereof. The inner layer 1 is the innermost layer because it is in direct contact with the fluorine-based refrigerant.

  In the present invention, the inner layer 1 is made of an inner layer material containing polypropylene as a main component, the intermediate layer 2 is made of an intermediate layer material containing polyamide as a main component, and the inner layer material contains an acid acceptor. I am letting. This is the greatest feature of the present invention.

Next, these components will be described.
《Inner layer》
The inner layer 1 is made of an inner layer material containing polypropylene as a main component and containing an acid acceptor.
In the present invention, the material for the inner layer mainly composed of polypropylene means that the majority of the material for the inner layer is occupied by polypropylene.

<polypropylene>
The polypropylene is preferably a modified polypropylene from the viewpoint of adhesiveness to the intermediate layer, and particularly preferably a maleic anhydride-modified polypropylene.

  The amount of modification of the maleic anhydride-modified polypropylene is preferably 0.26 to 0.36% by weight, particularly preferably 0.26 to 0.28% by weight. That is, if the modification amount is too low, the interlaminar adhesion tends to be deteriorated. Conversely, if the modification amount is too high, the heat resistance tends to be inferior.

  The melting point of the maleic anhydride-modified polypropylene is preferably 165 to 168 ° C. That is, if the melting point is too low, the heat resistance tends to be inferior, and conversely if the melting point is too high, the interlayer adhesion tends to deteriorate.

<Acid acceptor>
Examples of the acid acceptor include hydrotalcite, zinc oxide, magnesium oxide and the like. These may be used alone or in combination of two or more. Among these, hydrotalcite is preferable from the viewpoint of excellent acid accepting effect.

Examples of the hydrotalcite include Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ .3.5H ₂ O, Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ , Mg ₄ Al ₂ (OH) ₁₂ CO ₃ .3. 5H ₂ O, Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O, Mg ₅ Al ₂ (OH) ₁₄ CO ₃ .4H ₂ O, Mg ₃ Al ₂ (OH) ₁₀ CO ₃ .1.7H ₂ O Mg ₃ ZnAl ₂ (OH) ₁₂ CO ₃ .wH ₂ O, Mg ₃ ZnAl ₂ (OH) ₁₂ CO _{3 and the} like. These may be used alone or in combination of two or more.

  The average particle size of the acid acceptor is usually in the range of 0.02 to 0.6 μm, preferably in the range of 0.45 to 0.58 μm.

  In the present invention, the average particle diameter of the acid acceptor is a value measured by a fully automatic surface area measuring device (multi soap 12).

  The content of the acid acceptor is preferably in the range of 0.5 to 5 parts by weight, particularly preferably in the range of 1 to 4 parts by weight with respect to 100 parts by weight of the polypropylene. That is, if there is too little acid acceptor, the acid resistance will deteriorate, and there will be a tendency that cracking of the hose will not be sufficiently suppressed. Conversely, if there is too much acid acceptor, the workability and bending durability will be reduced. This is because it tends to get worse.

  The inner layer material contains a predetermined amount of an acid acceptor in polypropylene, and other additives (filler, plasticizer, anti-aging agent, antioxidant, flexible component, heat-resistant agent, etc.) as required. Can be prepared by blending as appropriate.

《Middle layer》
The intermediate layer 2 formed on the outer peripheral surface of the tubular inner layer 1 is made of an intermediate layer material mainly composed of polyamide.
In the present invention, the intermediate layer material containing polyamide as a main component means that the polyamide occupies a majority of the intermediate layer material, and includes a case where the material is composed only of polyamide.

<polyamide>
Examples of the polyamide include polyamide 6 (PA6), polyamide 46 (PA46), polyamide 66 (PA66), polyamide 92 (PA92), polyamide 99 (PA99), polyamide 610 (PA610), polyamide 612 (PA612), polyamide 1010 (PA1010), polyamide 11 (PA11), polyamide 912 (PA912), polyamide 12 (PA12), a copolymer of polyamide 6 and polyamide 66 (PA6 / 66), a copolymer of polyamide 6 and polyamide 12 ( PA6 / 12), aromatic nylon and the like. These may be used alone or in combination of two or more. Among these, polyamide 6 is preferable because it is excellent in interlayer adhesion and more excellent in low refrigerant permeability.

  The intermediate layer material should be blended with other additives (fillers, plasticizers, anti-aging agents, antioxidants, softening ingredients, nucleating agents, heat-resistant agents, etc.) as appropriate in the polyamide. Can be prepared.

《Rubber layer》
Examples of the main polymer (base material) of the inner rubber layer 3 and the outer rubber layer 5 (hereinafter sometimes simply referred to as “rubber layer”) include, for example, butyl rubber, ethylene-propylene rubber [ethylene-propylene -Diene terpolymer rubber (EPDM), ethylene-propylene copolymer rubber (EPM)], and the like. These may be used alone or in combination of two or more. Among these, a butyl rubber is preferable in terms of water blocking properties (water barrier properties), and an ethylene-propylene rubber is preferable in terms of heat resistance.

  The rubber layer in the refrigerant transport hose of the present invention is not limited to the two-layer structure (inner rubber layer 3, outer rubber layer 5) as shown in FIG. 3, intermediate rubber layer, outer rubber layer 5), or a multilayer structure of four or more layers may be used.

  A preferable combination of the rubber layers is, for example, 2 such as the inner rubber layer 3 (ethylene-propylene rubber layer or butyl rubber layer) / the outer rubber layer 5 (ethylene-propylene rubber layer or butyl rubber layer). Layer structure, inner rubber layer 3 (ethylene-propylene rubber layer or butyl rubber layer) / intermediate rubber layer (ethylene-propylene rubber layer or butyl rubber layer) / outer rubber layer 5 (ethylene-propylene rubber layer) Or a three-layer structure such as a butyl rubber layer).

<Butyl rubber>
Examples of the butyl rubber include butyl rubber (IIR) and halogenated butyl rubber. These may be used alone or in combination of two or more. Examples of the halogenated butyl rubber include chlorinated butyl rubber (Cl-IIR) and brominated butyl rubber (Br-IIR).

<Ethylene-propylene rubber>
Examples of the ethylene-propylene rubber include ethylene-propylene-diene terpolymer rubber (EPDM) and ethylene-propylene copolymer rubber (EPM).

  The diene monomer (third component) contained in the EPDM is preferably a diene monomer having 5 to 20 carbon atoms, specifically 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene. 2,5-dimethyl-1,5-hexadiene, 1,4-octadiene, 1,4-cyclohexadiene, cyclooctadiene, dicyclopentadiene (DCP), 5-ethylidene-2-norbornene (ENB), 5- Butylidene-2-norbornene, 2-methallyl-5-norbornene, 2-isopropenyl-5-norbornene and the like. Among these diene monomers (third component), dicyclopentadiene (DCP) and 5-ethylidene-2-norbornene (ENB) are preferable.

  The rubber layer material (rubber composition) for forming the rubber layers 3 and 5 includes a main polymer such as butyl rubber, a resin crosslinking agent, a resorcinol compound (adhesive component), a melamine compound ( Adhesive components), carbon black, fillers, softeners, tackifiers, processing aids, and the like can be appropriately blended as necessary.

<Resin cross-linking agent>
Examples of the resin crosslinking agent include formaldehyde condensates of alkylphenols. Specific examples of the resin cross-linking agent include alkylphenol-formaldehyde condensates (manufactured by Taoka Chemical Industry Co., Ltd., Tactrol 201MB35).

  The content of the resin crosslinking agent is preferably 20 to 40 parts by weight with respect to 100 parts by weight of the main polymer such as the butyl rubber.

<Resorcinol compound (adhesive component)>
The resorcinol-based compound is preferably one that mainly acts as an adhesive, and examples thereof include modified resorcin / formaldehyde resin, resorcin, resorcin / formaldehyde (RF) resin, and the like. These may be used alone or in combination of two or more. Among these, a modified resorcin / formaldehyde resin is preferably used in terms of transpiration and compatibility with rubber.

  Examples of the modified resorcin / formaldehyde resin include those represented by the following general formulas (1) to (3). These may be used alone or in combination of two or more. Among these, those represented by the general formula (1) are particularly preferable.

  The content of the resorcinol compound is preferably in the range of 0.1 to 10 parts by weight, particularly preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the main polymer such as the butyl rubber.

<Melamine compound (adhesive component)>
Examples of the melamine compound include methylated formaldehyde / melamine polymer, hexamethylenetetramine, and the like. These may be used alone or in combination of two or more. These decompose under heating during crosslinking and supply formaldehyde to the system. Among these, a methylated product of formaldehyde / melamine polymer is preferable in terms of low volatility and excellent compatibility with rubber.

  As the methylated product of the formaldehyde / melamine polymer, for example, those represented by the following general formula (4) are preferable. In particular, in the general formula (4), a mixture in which n = 1 is 43 to 44% by weight, n = 2 is 27 to 30% by weight, and n = 3 is 26 to 30% by weight is preferable.

  The content of the melamine compound is preferably 5 parts by weight or less with respect to 100 parts by weight of the main polymer such as the butyl rubber.

  Here, the mixing ratio of the resorcinol compound and the melamine compound is preferably in a range of 1: 0.5 to 1: 2, more preferably 1: 0.77 to 1: 1.5 in terms of weight ratio. It is a range.

<Carbon black>
Examples of the carbon black include grades such as SAF class, ISAF class, HAF class, MAF class, FEF class, GPF class, SRF class, FT class, and MT class. These may be used alone or in combination of two or more.

  The carbon black content is preferably in the range of 30 to 150 parts by weight with respect to 100 parts by weight of the main polymer such as the butyl rubber.

<filler>
Examples of the filler include inorganic compounds derived from minerals such as talc and mica. These may be used alone or in combination of two or more.

  The content of the filler is preferably in the range of 1 to 200 parts by weight with respect to 100 parts by weight of the main polymer such as the butyl rubber.

<Softener>
Examples of the softener include petroleum oil softeners such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt and petroleum jelly, fatty oil softeners such as castor oil, linseed oil, rapeseed oil and coconut oil, tall Examples thereof include waxes such as oil, sub, beeswax, carnauba wax and lanolin, linoleic acid, palmitic acid, stearic acid, lauric acid and the like. These may be used alone or in combination of two or more.

  The content of the softening agent is preferably 40 parts by weight or less with respect to 100 parts by weight of the main polymer such as the butyl rubber.

  The rubber layer material (rubber composition) can be prepared by blending each component and kneading with a roll or the like.

《Reinforcement layer》
As a material for forming the reinforcing layer 4, for example, a reinforcing wire such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), aramid, polyamide, vinylon, rayon, metal wire or the like can be used. The reinforcing layer 4 can be produced by braiding the reinforcing wire with a spiral braid, a blade braid, a knit braid, or the like.

  Below, the manufacturing method of the hose for refrigerant | coolant transport of this invention is demonstrated. That is, first, an inner layer material containing polypropylene as a main component and containing an acid acceptor is prepared, and an intermediate layer material containing polyamide as a main component is prepared. Further, other components are blended in a predetermined ratio with the main polymer such as butyl rubber, and these are kneaded to prepare rubber layer materials (inner rubber layer material and outer rubber layer material). Next, the inner layer material and the intermediate layer material are extruded on a mandrel in a hose shape to form the intermediate layer 2 on the outer peripheral surface of the inner layer 1. If necessary, the mandrel may be omitted. Next, after the inner surface rubber layer material is extruded on the outer peripheral surface of the intermediate layer 2 to form the inner rubber layer 3, a reinforcing yarn such as PET yarn is braided on the outer peripheral surface by braiding the reinforcing layer 4 and the like. Form. Further, the outer rubber layer material is extruded on the outer peripheral surface of the reinforcing layer 4 to form the outer rubber layer 5 and then vulcanized under predetermined conditions. In this way, the intermediate layer 2 is formed on the outer peripheral surface of the inner layer 1, and the inner surface rubber layer 3, the reinforcing layer 4, and the outer rubber layer 5 are sequentially formed on the outer peripheral surface thereof (see FIG. 1). Can be produced.

  In the refrigerant transport hose of the present invention, the inner diameter of the hose is preferably in the range of 5 to 40 mm. The thickness of the inner layer 1 is preferably in the range of 0.02 to 2 mm, the thickness of the intermediate layer 2 is preferably in the range of 0.02 to 2 mm, and the thickness of the rubber layers 3 and 5 is 0.5. A range of ˜5 mm is preferred.

  The refrigerant transport hose of the present invention is not limited to the structure shown in FIG. 1, and as described above, the structure has three or more rubber layers, for example, an inner layer / intermediate layer / inner rubber layer. There may be a layer structure such as / reinforcing layer / intermediate rubber layer / reinforcing layer / outer rubber layer. In the case where unmodified polypropylene (non-modified PP) is used as the inner layer material, an adhesive layer may be formed at the interface between the inner layer 1 and the intermediate layer 2. Further, the above acid acceptor may be blended in the adhesive layer.

  Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples.

  First, prior to Examples and Comparative Examples, the following inner layer materials, intermediate layer materials, and rubber layer materials (rubber compositions) were prepared.

(Preparation of inner layer material)
As maleic anhydride-modified polypropylene (modified PP), Mitsui Chemicals, Inc., ADMER QF500 (modified amount 0.27 wt%, melting point 165 ° C.) was prepared. And in this modified PP, the acid acceptor (hydrotalcite, magnesium oxide, zinc oxide) shown in the following Table 1 was blended in the ratio shown in the same table to prepare an inner layer material. In addition, as the acid acceptor, hydrotalcite (manufactured by Kyowa Chemical Industry Co., Ltd., DHT-4A), magnesium oxide (manufactured by Kyowa Chemical Industry Co., Ltd., Kyowa Mag # 150), zinc oxide (manufactured by Mitsui Kinzoku Mining Co., Ltd., one type of zinc oxide) )It was used.

[Preparation of intermediate layer material]
As an intermediate layer material, polyamide 6 (PA6) (manufactured by Ube Industries, nylon 6 1018I) was prepared.

[Preparation of EPDM rubber composition]
100 parts by weight of EPDM (manufactured by Sumitomo Chemical Co., Ltd., Esprene 501A), 100 parts by weight of carbon black (manufactured by Tokai Carbon Co., Seast SO), 60 parts by weight of process oil (manufactured by Idemitsu Kosan Co., Ltd., Diana Process PW-380) , 4.2 parts by weight of di-t-butylperoxy-diisopropylbenzene (manufactured by NOF Corporation, Peroximon F-40) as a peroxide crosslinking agent, and a modified resorcin represented by the general formula (1) as a resorcinol compound -1 part by weight of formaldehyde resin (Sumitomo Chemical Industries, Sumikanol 620) and 0.77 parts by weight of methylated formaldehyde / melamine polymer (Sumitanol Chemicals, Sumikanol 507A) as melamine resin, Banbury mixer (manufactured by Kobe Steel) and roll (Nippon Roll Co., Ltd.) ) Were kneaded was used to prepare EPDM-based rubber composition.

[Examples 1 to 4, Comparative Example 1]
A hose was produced using the inner layer material, intermediate layer material, and rubber composition (inner rubber layer material, outer rubber layer material) shown in Table 1 below. That is, the inner layer material and the intermediate layer material were extruded into a hose shape on a mandrel (outer diameter: 12 mm) made by TPX (Mitsui Chemicals) to form an intermediate layer on the outer peripheral surface of the inner layer. Next, an inner surface rubber layer material was extruded on the outer peripheral surface of the intermediate layer to form an inner rubber layer, and then a reinforcing layer was formed on the outer peripheral surface with a braid of PET yarn. Further, the outer rubber layer material was extruded on the outer peripheral surface of the reinforcing layer to form an outer rubber layer. Then, after vulcanization (170 ° C. × 30 minutes), the long laminated hose is cut into a desired length, so that the inner layer (thickness 0.1 mm), the intermediate layer (thickness 0.1 mm), the inner surface A hose in which a rubber layer (thickness 1.0 mm), a reinforcing layer, and an outer rubber layer (thickness 2.0 mm) were sequentially formed was produced (inner diameter 12.0 mm).

  Using the hoses of Examples and Comparative Examples thus obtained, refrigerant resistance / refrigeration oil resistance was evaluated according to the following criteria. These results are also shown in Table 1 above.

[Refrigerant / refrigeration oil resistance (bending durability)]
Both ends of a hose with a length of about 400 mm are crimped with aluminum fittings, 6 g of refrigerant (HFC-134a), about 13 g of polyalkylene glycol (PAG) refrigerating machine oil (Idemitsu Kosan Co., Ltd., Daphne Hermetic Oil NF), water (distilled water) ) After filling 15,000 ppm and aging at a predetermined temperature for a predetermined time (120 ° C. × 500 hours, 150 ° C. × 168 hours), the hose was divided in half and visually checked for cracks.
<Evaluation>
○: No crack ×: With crack

  From the result of the said Table 1, since Examples 1-4 contain the acid-accepting agent (hydrotalcite, magnesium oxide, zinc oxide) in the material for inner layers, it is refrigerant-resistant and refrigeration oil resistance (bending durability). Was excellent. The inventor has confirmed by experiments that the same excellent effects as in the examples using PA6 can be obtained when PA6 and PA612 are used instead of PA6 as the intermediate layer material. Further, the present inventor uses the outer rubber layer made of the EPDM rubber composition even when the outer rubber composition made of the butyl rubber composition is used instead of the outer rubber layer made of the EPDM rubber composition. It has been confirmed by experiments that excellent effects similar to those of the above examples can be obtained.

  On the other hand, since the comparative example 1 did not contain the acid acceptor in the inner layer material, the refrigerant resistance / refrigerating machine oil resistance (bending durability) was inferior.

  The refrigerant transport hose of the present invention is used for an air conditioner hose or the like for transporting a fluorine-based refrigerant such as chlorofluorocarbon or alternative chlorofluorocarbon. The refrigerant transport hose can be used not only for automobiles, but also for other transport machines (industrial transport vehicles such as airplanes, forklifts, excavators, cranes, railway vehicles, etc.).

DESCRIPTION OF SYMBOLS 1 Inner layer 2 Middle layer 3 Inner surface rubber layer 4 Reinforcement layer 5 Outer surface rubber layer

Claims (7)

  A refrigerant transport hose comprising a tubular inner layer in contact with a fluorine-based refrigerant, an intermediate layer formed on an outer peripheral surface thereof, and at least one rubber layer formed on the outer periphery thereof, wherein the inner layer is made of polypropylene. A refrigerant transport hose comprising an inner layer material containing a main component and an acid acceptor, wherein the intermediate layer is made of an intermediate layer material containing polyamide as a main component.   The refrigerant transport hose according to claim 1, wherein the acid acceptor is at least one selected from the group consisting of hydrotalcite, zinc oxide, and magnesium oxide.   The refrigerant transport hose according to claim 1 or 2, wherein the content of the acid acceptor is in the range of 0.5 to 5 parts by weight with respect to 100 parts by weight of polypropylene.   The refrigerant transport hose according to any one of claims 1 to 3, wherein the polypropylene of the inner layer material is maleic anhydride-modified polypropylene.   The refrigerant transport hose has an inner layer formed on the outer peripheral surface of the inner layer, an inner rubber layer formed on the outer peripheral surface, a reinforcing layer formed on the outer peripheral surface, and an outer rubber layer formed on the outer peripheral surface. The refrigerant transport hose according to any one of claims 1 to 4, wherein the hose for transporting a refrigerant is used.   6. The refrigerant transport hose according to claim 5, wherein the inner rubber layer is an ethylene-propylene rubber layer.   The refrigerant transport hose according to claim 5 or 6, wherein the outer rubber layer is a butyl rubber layer or an ethylene-propylene rubber layer.

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