JP2006002130A - Polyamide composite resin and hose for transportation of refrigerant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyamide composite resin superior in gas barrier property, superior enough in flexibility and durability, and capable of forming a good gas barrier layer for a hose for transportation of a refrigerant without forming multilayer structure, and to provide the hose for transportation of the refrigerant that can easily be manufactured using the polyamide composite resin. <P>SOLUTION: This polyamide composite resin comprises a polyamide and a polyolefin, wherein the polyamide has a structural unit of m-xylenediamine. The polyamide composite resin having superior gas barrier property, flexibility and durability is obtained by a polymer alloy in which polyolefin as a softening agent is added to the polyamide. The hose for transportation of the refrigerator has the innermost layer composed of the polyamide composite resin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is excellent in flexibility and gas barrier properties, and by using this as the innermost layer of a refrigerant transport hose, a refrigerant transport hose excellent in gas barrier properties (refrigerant permeability), dynamic durability, and flexibility can be obtained. The present invention relates to a polyamide-based composite resin that can be provided, and a refrigerant transport hose using the polyamide-based composite resin.

  Refrigerant transport hoses used for piping and the like of automobile air conditioners are roughly classified into high pressure lines and low pressure lines. The high-pressure line is a line that supplies high-temperature refrigerant compressed into a gas-liquid mixture by a compressor to the condenser at high pressure. The low-pressure line is a line for returning the low-pressure / low-temperature refrigerant evaporated by the evaporator to the compressor.

  The refrigerant transport hose has excellent gas barrier properties that can reliably prevent the leakage of refrigerant (Freon), flexibility to ensure the routing of the refrigerant transport hose in narrow spaces, and durability Properties such as aging resistance, impact resistance, and mechanical strength are required, but especially for gas barrier properties, the amount of refrigerant leakage in the high-pressure line is significant due to its mechanism, so high gas barrier properties are required. It has been.

  In order to ensure gas barrier properties and flexibility, the conventional refrigerant transport hose has an innermost layer made of a composite resin obtained by adding a polyolefin as a flexibility-imparting agent to a polyamide-based resin such as polyamide 6 (nylon 6). It is arranged as a gas barrier layer and has a multilayer structure in which a rubber layer is coated on the outer periphery. In the innermost layer, although the flexibility is improved by blending the polyolefin, the gas barrier property of the polyolefin itself is inferior to that of polyamide, and as a result, the gas barrier property of the innermost layer made of the composite resin is impaired.

  Therefore, in order to solve this problem, the present applicant firstly used a refrigerant transport hose excellent in gas barrier properties and flexibility, in which the innermost layer was polyamide 6:58 to 72 parts by weight and polyolefin: 42 to 28 parts by weight. Proposing a refrigerant transport hose comprising a resin layer with a sea-island structure in which the sea phase is polyamide 6, the island phase is polyolefin, and the polyamide 6 is dispersed in a dispersed manner in the polyolefin island phase (Japanese Patent Laid-Open No. 2000-120944).

  In this refrigerant transport hose, since the innermost resin layer has the polyamide 6 phase scattered in the form of scattered dots in the polyolefin island phase, the polyolefin island phase is present inside the original volume of the polyolefin. The apparent volume fraction increases by the amount of the polyamide 6 phase. Thus, when the apparent volume fraction of the island phase of polyolefin becomes large, the improvement effect of the softness | flexibility provision effect similar to the case where the compounding quantity of polyolefin is increased is acquired. For this reason, the blending amount of the actual polyolefin can be kept low, and therefore a good flexibility improvement effect can be obtained without causing a decrease in gas barrier properties due to the blending of the polyolefin.

  However, even the refrigerant transport hose disclosed in Japanese Patent Application Laid-Open No. 2000-120944 cannot be said to have sufficient gas barrier properties, particularly in high-pressure line applications, and further improvements are required.

Therefore, as a refrigerant transport hose having excellent gas barrier properties and dynamic durability such as impulse resistance and flexibility, the present applicant has applied a polyamide (hereinafter referred to as “polyamide MX”) as a structural unit of metaxylenediamine. In other words, a polyamide-based composite resin having a resin layer composed of “A)” has been proposed (Japanese Patent Application No. 2004-104947).
JP 2000-120944 A Japanese Patent Application No. 2004-104947

  However, although polyamide MX is excellent in gas barrier performance, the material itself is very hard, so that it can sufficiently satisfy the durability performance such as impulse resistance after long-term heat aging and vibration durability test required for a hose. Absent. Therefore, in Japanese Patent Application No. 2004-104947, the polyamide MX layer having excellent gas barrier properties is provided as the gas barrier layer, and the resin layer responsible for flexibility and dynamic durability is provided as the innermost layer, thereby solving the above-mentioned problems.

  However, in this Japanese Patent Application No. 2004-104947, it is necessary to have a multilayer structure of a polyamide MX layer responsible for gas barrier properties and a resin layer responsible for flexibility and durability. In production, high production technology and expensive multilayer extrusion are required. There is a problem of requiring equipment.

  Accordingly, the present invention is a polyamide-based composite resin that is excellent in gas barrier properties and sufficiently excellent in flexibility and durability, and can form a good gas barrier layer of a refrigerant transport hose without having a multilayer structure. And it aims at providing the hose for refrigerant | coolants transport which can be manufactured easily using this polyamide-type composite resin.

  The polyamide-based composite resin of the present invention is a polyamide-based composite resin containing polyamide and polyolefin, wherein the polyamide is a polyamide having meta-xylenediamine as a structural unit.

  A polyamide-based composite resin excellent in gas barrier properties, flexibility, and durability can be realized as long as it is a polyamide-based composite resin obtained by adding a polyolefin as a flexibility-imparting agent to polyamide MX.

  In this invention, it is preferable that the content rate of polyolefin as a softness | flexibility imparting agent is 10 to 40 weight%. The polyolefin is preferably a modified polyolefin or a mixture of a modified ponolefin and an unmodified polyolefin.

  The refrigerant transport hose of the present invention is characterized by including a layer made of the polyamide-based composite resin of the present invention.

  The refrigerant transport hose of the present invention preferably includes an innermost layer made of a polyamide-based composite resin, and the innermost layer preferably has a thickness of 50 to 300 μm.

  According to the present invention, a high-performance refrigerant transport hose can be easily manufactured by using a polyamide-based composite resin excellent in gas barrier properties, flexibility, and durability.

  Hereinafter, embodiments of the polyamide-based composite resin and the refrigerant transport hose of the present invention will be described in detail.

  First, the polyamide-based composite resin of the present invention will be described.

  The polyamide-based composite resin of the present invention is a polymer alloy obtained by adding polyolefin as a flexibility-imparting agent to polyamide MX.

  Polyamide MX, that is, metaxylenediamine of polyamide having metaxylenediamine as a structural unit is represented by the following structural formula, for example.

  In the present invention, the polyamide MX may be a homopolymer composed only of such metaxylenediamine, or may be a copolymer of metaxylenediamine and another monomer. In the case of a copolymer, metaxylenediamine is preferably contained in an amount of 60% by weight or more.

  Examples of polyolefins include modified EPR (ethylene-propylene copolymer), modified EPDM (ethylene-propylene-diene terpolymer), ionomer, α-olefin copolymer, modified IR (isoprene rubber), and modified SEBS (styrene). -Ethylene-butylene-styrene copolymer), halogenated isobutylene-paramethylstyrene copolymer, ethylene-acrylic acid modified product, ethylene-ethyl acrylate copolymer, acid modified product thereof, and their main components. A mixture etc. are mentioned.

  Polyolefins, especially those modified with acid anhydrides such as maleic anhydride, alkyl acrylate esters such as glycidyl methacrylate, epoxies, and modified products thereof, can obtain a fine alloy structure based on polyamide. It is possible and preferable.

  If the polyolefin content in the polyamide-based composite resin of the present invention is too small, the effect of improving the flexibility and durability due to the blending of the polyolefin cannot be sufficiently obtained, and if too much, the gas barrier property is lowered. The content in the polyamide-based composite resin is preferably 10 to 40% by weight, particularly preferably 20 to 30% by weight. If the content of the polyolefin in the polyamide-based composite resin exceeds 40% by weight, the sea phase and the island phase are reversed in the sea-island structure described later, and the gas barrier property is remarkably lowered.

  When a modified polyolefin such as acid-modified polyolefin is used as the polyolefin, a large amount of the resin causes gelation of the resin, and when extruding, it causes poor appearance such as rough skin (fisheye). When used, the content in the polyamide-based composite resin is preferably 30% by weight or less, for example, 5 to 25% by weight.

  Thus, by blending polyolefin with polyamide MX, flexibility and durability are improved, but a decrease in gas barrier properties is inevitable. However, by adopting a fine alloy structure of polyamide MX and polyolefin, in particular, the island phase of polyolefin is dispersed in the sea phase of polyamide MX and the polyamide MX is dispersed in the form of dots in the island phase of polyolefin. With such a structure, a decrease in gas barrier properties due to blending of polyolefin can be suppressed, which is preferable.

  In particular, the ratio of the polyamide MX phase existing in the form of dots in the island phase of the polyolefin to the polyamide MX (the total of the polyamide MX constituting the sea phase and the polyamide MX phase existing in the form of dots in the island phase of the polyolefin) (Hereinafter, the ratio is referred to as “scattered dispersion”.) Is preferably about 2.5 to 30% by weight. If this proportion is less than 2.5% by weight, the effect of having the polyamide MX phase present in the form of scattered dots in the polyolefin island phase cannot be sufficiently obtained. As a result, the gas barrier property may be lowered due to too little polyamide MX phase.

  The size of the polyolefin island phase and the size of the polyamide MX phase in the polyolefin island phase are approximately 0.4 to 1.5 μm in the size of the polyolefin island phase and 0.05 in the size of the polyamide MX phase. It is preferable that it is about -0.5 micrometer.

  The polyamide of the polyamide composite resin of the present invention does not necessarily need to be polyamide MX, and may contain a polyamide such as polyamide 6 other than polyamide MX. In order to ensure gas barrier properties, it is preferable that 51% by weight or more of the total polyamide component is a metaxylenediamine component.

  Moreover, you may add additives, such as anti-aging agent and an oxidative degradation agent, to the polyamide-type composite resin of this invention as needed.

The polyamide-based composite resin of the present invention, particularly the polyamide-based composite resin having a sea-island structure as described above, can be produced, for example, by the following method (1) or (2).
(1) A method in which polyamide MX and polyolefin are kneaded at a predetermined mixing ratio to form a master batch, and then the master batch and polyamide MX are kneaded.
(2) A method of melt-kneading polyamide MX and a polyolefin blend by high shear.

  Next, the refrigerant transport hose of the present invention having such a layer made of the polyamide-based composite resin of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing an embodiment of a refrigerant transport hose according to the present invention, and FIGS. 2A and 2B show another embodiment of the resin layer of the refrigerant transport hose according to the present invention. It is a perspective view shown.

  The refrigerant transport hose 10 shown in FIG. 1 is configured such that an inner tube layer 3 composed of a resin layer 1 and an inner tube rubber layer 2 is covered with an outer rubber 5 via an intermediate rubber layer 4 including a reinforcing thread. . An adhesive layer may be provided between the resin layer 1 and the inner tube rubber layer 2 as necessary.

  The resin layer 1 is comprised by the polyamide-type composite resin of the above-mentioned this invention. The thickness of the resin layer 1 is preferably as thick as possible in terms of the gas barrier properties and durability of the hose. On the other hand, when the thickness of the resin layer 1 is increased, the flexibility of the hose is sacrificed. Accordingly, the thickness of the resin layer 1 is preferably 30 to 300 μm, particularly 50 to 200 μm.

  The resin layer 1 made of the polyamide-based composite resin of the present invention can be used as an innermost layer of a refrigerant transport hose even in a single layer structure, as an impulse resistance after long-term heat aging, a vibration endurance test after an impulse test, and a motion after heat aging. The refrigerant transportation hose using the polyamide-based composite resin of the present invention can be provided with a multilayer transport hose having excellent durability performance such as a mechanical durability test and excellent gas barrier performance. Co-extrusion for making the structure is unnecessary, and it can be easily manufactured.

  However, in the refrigerant transport hose of the present invention, the resin layer does not necessarily have a single layer structure as shown in FIG. 1, and the total thickness of the hose is excessively increased to impair flexibility, increase cost, and weight. In a range where no increase is caused, as shown in FIGS. 2A and 2B, the resin layers may be laminated resin layers 1A and 1B. 2A and 2B show laminated resin layers 1A and 1B as an alternative to the resin layer 1 of the refrigerant transport hose 10 in FIG. 1, and the other configurations are the same. An inner tube rubber layer 2, an intermediate rubber layer 4, and a jacket rubber 5 are further formed on the laminated resin layers 1A and 1B in the same manner as in FIG.

  The laminated resin layer 1A in FIG. 2A is laminated from the inside in the order of the first resin layer 1a-1, the second resin layer 1b, and the first resin layer 1a-2, and is an alternating laminated structure of three layers. Further, the laminated resin layer 1B of FIG. 2B is composed of the first resin layer 1a-1, the second resin layer 1b-1, the first resin layer 1a-2, and the second resin layer from the inside. This is a five-layered alternately laminated structure in which the resin layer 1b-2 and the first resin layer 1a-3 are laminated in this order.

  Here, the first resin layers 1a-1, 1a-2, 1a-3 are layers mainly responsible for durability and flexibility, preferably polyamide 6: 58 to 72 parts by weight and polyolefin: 42 to 28 parts by weight. Part (however, the total of polyamide 6 and polyolefin is 100 parts by weight), and the island phase of polyolefin is dispersed in the sea phase of polyamide 6, and the polyamide 6 is scattered in the island phase of this polyolefin. It is made of a polyamide 6-polyolefin composite resin having a structure dispersed in a shape. Here, when the polyamide 6 of the polyamide 6-polyolefin composite resin is less than 58 parts by weight, the gas barrier property is inferior even if the morphology of the specific sea-island structure is used. On the other hand, when the amount of polyamide 6 is more than 72 parts by weight, even if it is a morphology of the specific sea-island structure, the flexibility is inferior.

  Even if the polyamide 6-polyolefin composite resin is in the composition range of the specific polyamide 6-polyolefin, good gas barrier properties and flexibility can be obtained when the specific sea-island structure morphology is not exhibited. Can not. In order to achieve the best gas barrier properties and flexibility, particularly for polyamide 6 (the total of polyamide 6 constituting the sea phase and the polyamide 6 phase existing in the form of scattered dots in the island phase of polyolefin). It is preferable that the ratio of the polyamide 6 phase existing in the form of dots in the island phase of the polyolefin (hereinafter, the ratio is referred to as “scattered dispersion”) is about 2.5 to 30% by weight. If this proportion is less than 2.5% by weight, the above-mentioned effect due to the presence of the polyamide 6 phase in the form of scattered dots in the polyolefin island phase cannot be sufficiently obtained. Conversely, if it exceeds 30% by weight, The polyamide 6 phase as the sea phase is too small and the gas barrier property may be lowered.

  The size of the polyolefin island phase and the size of the polyamide 6 phase in the polyolefin island phase are approximately 0.4 to 1.5 microns for the polyolefin island phase and 0. It is preferable that it is about 05-0.5 micron.

  In addition, as polyolefin, modified EPR (ethylene-propylene copolymer), modified EPDM (ethylene-propylene-diene terpolymer), ionomer, α-olefin copolymer, modified IR (isoprene rubber), modified SEBS. (Styrene-ethylene-butylene-styrene copolymer), halogenated isobutylene-paramethylstyrene copolymer, ethylene-acrylic acid modified product, ethylene-ethyl acrylate copolymer, acid modified product thereof, and main components thereof And the like.

  You may add additives, such as an anti-aging agent and an oxidation deterioration agent, to this polyamide 6-polyolefin type composite resin as needed.

In addition, as a method of forming a morphology of the specific sea-island structure of the polyamide 6-polyolefin composite resin,
(1) A method in which polyamide 6 and polyolefin are kneaded at a predetermined mixing ratio to form a master batch, and then the master batch and polyamide 6 are kneaded.
(2) A method in which polyamide 6 and a polyolefin blend are melt-kneaded by high shear.
Etc.

  The second resin layers 1b, 1b-1, and 1b-2 are layers mainly responsible for gas barrier properties, and are composed of the polyamide-based composite resin of the present invention.

  In the laminated resin layer 1A having a three-layer laminated structure shown in FIG. 2A, the film thicknesses of the first resin layers 1a-1 and 1a-2 are 200 μm, respectively, and the film thickness of the second resin layer 1b is 100 μm. It is preferable. Further, in the laminated resin layer 1B having a five-layer structure shown in FIG. 2B, the first resin layers 1a-1 and 1a-3 each have a thickness of 100 μm, and the film of the first resin layer 1a-2. It is preferable that the thickness is 200 μm, and the thickness of each of the second resin layers 1b-1 and 1b-2 is 50 μm.

  The multilayer resin layers 1A and 1B having such a multilayer structure can be easily manufactured by integral molding by co-extrusion of the plurality of resin layers. In this case, the first resin layer and The second resin layer is made of polyamide as a base resin, and because of the familiarity of both, it is firmly bonded by co-extrusion, so it is necessary to perform special treatment for adhesion between the layers. There is no.

  There is no restriction | limiting in particular about the other structure of the refrigerant | coolant transport hose of this invention, The structure of the normal refrigerant | coolant transport hose is employable.

  For example, in the refrigerant transport hose 10 shown in FIG. 1, as the rubber constituting the inner tube rubber layer 2 and the jacket rubber 5, generally butyl rubber (IIR), chlorinated butyl rubber (C1-IIR), chlorinated polyethylene, chloro Sulfonated polyethylene, brominated butyl rubber (Br-IIR), isobutylene-bromoparamethylstyrene copolymer, EPR (ethylene-propylene copolymer), EPDM (ethylene-propylene-diene terpolymer), NBR (acrylonitrile) Butadiene rubber), CR (chloroprene rubber), hydrogenated NBR, acrylic rubber, blends of two or more of these rubbers, or blends with polymers based on these rubbers, preferably butyl rubber, EPDM System rubber is used. These rubbers can be applied with compounding recipes such as commonly used fillers, processing aids, anti-aging agents, vulcanizing agents, and vulcanization accelerators.

  The rubber type of the inner rubber layer 2 and the rubber type of the jacket rubber 5 may be the same type or different types.

  Moreover, the rubber | gum of the intermediate | middle rubber layer 4 should just have the adhesiveness with the inner tube | pipe rubber layer 2 and the jacket rubber 5, and there is no restriction | limiting in particular.

  The reinforcing yarn is not particularly limited as long as it is usually used. In general, polyester, wholly aromatic polyester, nylon, vinylon, rayon, aramid, polyarylate, polyethylene naphthalate and blended yarns thereof are used.

  The thickness of the inner tube rubber layer 2 is preferably about 0.8 to 4 mm from the viewpoint of flexibility. Furthermore, it is preferable that the thickness of the intermediate rubber layer 4 including the reinforcing yarn is about 0.5 to 5 mm, and the thickness of the outer rubber layer 5 is about 1 to 2 mm.

  Such a refrigerant transport hose of the present invention is manufactured by extruding and laminating the material of each constituent layer to a predetermined thickness on a mandrel and vulcanizing at 140 to 170 ° C. for 30 to 120 minutes according to a conventional method. can do.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

  The rubber ratios of the inner rubber layer, the intermediate rubber layer, and the outer rubber layer used in the following examples and comparative examples are as shown in Tables 1 to 3 below.

Examples 1-5, Comparative Examples 1-3
A refrigerant transport hose having the structure shown in FIG. 1 was manufactured by the following procedure using the following materials for the resin layer.
Polyamide MX: MX nylon “S6001” manufactured by Mitsubishi Gas Chemical Company
Polyolefin: α-olefin polymer “Tuffmer A-1050” manufactured by Mitsui Chemicals, Inc.
Acid-modified polyolefin: Maleic acid-modified α-olefin polymer manufactured by Mitsui Chemicals, Inc.
"Toughmer MH7010"
Polyamide: 6 nylon “1022B” manufactured by Ube Industries, Ltd.

  A resin layer 1 having a thickness of 150 μm was formed on a mandrel having a diameter of 11 mm by extrusion with a resin composition shown in Table 4, and then the inner layer rubber shown in Table 1 was extruded to a thickness of 1.2 mm. On top of this, 24 3,000 denier polyester reinforcing yarns were aligned and wound in a spiral shape, and the intermediate rubber shown in Table 2 was extruded to a thickness of 0.3 mm on this reinforcing yarn layer. Further, 3000 denier polyester was further formed thereon. Twenty-four reinforcing yarns were aligned and wound in a spiral shape in the opposite direction. Next, the jacket rubber shown in Table 3 was extruded to a thickness of 1.3 mm and vulcanized at 150 ° C. for 90 minutes to obtain a refrigerant transport hose.

  The obtained refrigerant transport hose was examined for flexibility, dynamic durability and gas barrier properties by the following methods, and was extremely excellent (◎◎), excellent (◎), good (○), good and normal (△ (Circle), normal ((triangle | delta)), defect (*), and very bad (xx) were evaluated, and the result was shown in Table 4.

  In the polyamide composite resin of the resin layer in the examples, a polyolefin island phase having a diameter of about 0.5 to 2.0 μm is dispersed in the sea phase of polyamide MX, and the diameter is 0 in the island phase of this polyolefin. Polyamide MX of about .04 to 0.45 μm was dispersed in the form of scattered dots, and the scattered dot-like dispersion ratio obtained from the transmission electron microscope image was as shown in Table 4.

  In addition, regarding the extrusion characteristics of the resin layer, the results of evaluating the quality in the same manner as above were as shown in Table 4.

[Flexibility test]
The load was measured when the hose was wound around a mandrel having a radius of 100 mm by a half turn.

[Dynamic durability test]
After enclosing PAG oil inside and preliminarily aging at 130 ° C for 30 days, attach the hose upside down with a mounting span of 270 mm, and perform the following repeated pressurization using PAG oil as a medium, The inner surface state after 150,000 rotations was observed.
Atmospheric temperature: 130 ° C
Pressure: 0.1 MPa to 3.5 MPa
Pressure cycle: 15 cpm
Number of times: 150,000 times

[Gas barrier property test]
Refrigerant HFC134a was sealed in a hose at 0.6 g / cm ^3, and the amount of weight loss when left at 90 ° C. for 96 hours was measured as the refrigerant permeation amount.

Example 6
As shown in FIG. 2 (a), the resin layer by coextrusion is a laminated resin layer 1A having a three-layer structure of the following blend A / blend B / blend A, and the thickness of each layer is as shown in Table 5. Then, a refrigerant transport hose was produced in the same manner as in Example 1 and evaluated in the same manner. The results are shown in Table 5.
Formulation A: Polyamide 6 (Ube Industries, Ltd. “1022B”) 72% by weight and polyolefin (Mitsui Chemicals, Inc., “Toughmer MH5010”) 28% by weight, kneaded with polyamide 6 in the sea phase of polyolefin 6 A resin in which the phases are dispersed, the dispersed particle diameter is 0.5 to 1.5 μm, and the scattered dispersion is 5.1% by weight.
Formula B: Polyamide MX (“S6001” manufactured by Mitsubishi Gas Chemical Co., Ltd.) 80% by weight and polyolefin (“Tuffmer MH5010” manufactured by Mitsui Chemicals, Inc.) 20% by weight were kneaded to obtain a polyamide MX sea phase with polyolefin. Resin in which the island phase is dispersed, the dispersed particle diameter is 0.5 to 1.5 μm, and the scattered dispersion is 5.1% by weight.

Comparative Example 4
In Example 6, a refrigerant transport hose was produced in the same manner except that only the first resin layer 1a-1 was used as the resin layer, and evaluated in the same manner. The results are shown in Table 5.

  From Tables 4 and 5, the refrigerant transport hose using the polyamide-based composite resin of the present invention exhibits excellent gas barrier properties, particularly in the case of high-pressure line compatibility, and is also excellent in flexibility and dynamic durability. I understand.

It is a perspective view which shows embodiment of the hose for refrigerant | coolant transportation of this invention. It is a perspective view which shows other embodiment of the resin layer of the hose for refrigerant | coolant transport which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resin layer 1A, 1B Laminated resin layer 1a-1, 1a-2, 1a-3 1st resin layer 1b, 1b-1, 1b-2 2nd resin layer 2 Inner tube rubber layer 3 Inner tube layer 4 Middle Rubber layer 5 Outer rubber 10 Refrigerant transport hose

Claims (6)

  A polyamide-based composite resin comprising a polyamide and a polyolefin, wherein the polyamide is a polyamide having meta-xylenediamine as a structural unit.   2. The polyamide-based composite resin according to claim 1, wherein the polyolefin content is 10 to 40% by weight.   3. The polyamide-based composite resin according to claim 2, wherein the polyolefin is a modified polyolefin or a mixture of a modified ponolefin and an unmodified polyolefin.   The sea phase according to any one of claims 1 to 3, wherein the sea phase is polyamide, the island phase is polyolefin, and the polyamide is dispersed in the island phase of the polyolefin. Characteristic polyamide composite resin.   A refrigerant transport hose comprising a layer made of the polyamide-based composite resin according to any one of claims 1 to 4.   6. The refrigerant transport hose according to claim 5, further comprising an innermost layer made of the polyamide-based composite resin, wherein the innermost layer has a thickness of 30 to 300 μm.

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