Resin material for hoses and hoses

Abstract

To provide a resin material for a hose used in a hose for an air conditioner mainly installed in a vehicle, and having improved durability under a high-temperature environment, and provide the hose.SOLUTION: A resin material M is formed into a cylindrical shape and used as an inner surface layer 2, an intermediate layer 4 and an outer surface layer 5 of a hose 1, and components 6A, 6B, 6C, 6D of an air conditioner 6 are connected to each other via the hose 1. The resin material has a breaking elongation of 50% or more and a plasticizer content of 3 mass% or less with respect to the total mass of the resin material M under an environmental condition of a predetermined temperature T of 100°C or more and 150°C or less, and further has a breaking strength of 5 MPa or more, a breaking elongation of 500% or less, and 10% modulus of 3 MPa or less under an environmental condition of the predetermined temperature T.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a resin material for a hose and a hose, and more particularly to a resin material used mainly for an air conditioner hose mounted on a vehicle, and said hose. [Background technology]

[0002] Air conditioners installed in vehicles such as automobiles have a circulation path that circulates the refrigerant. This circulation path is formed by connecting components such as the compressor, condenser, separator dryer (receiver dryer), and evaporator via hoses.

[0003] Since these hoses must be able to withstand the internal pressure caused by the refrigerant flowing through them, metal pipes and rubber hoses are widely used. In recent years, there has been a demand for lighter automobiles from the standpoint of reducing the burden on the environment and improving energy efficiency.

[0004] Various resin hoses have been proposed as hoses for automotive air conditioners (hoses for air conditioners) (see, for example, Patent Document 1). Such resin hoses are advantageous in terms of weight reduction compared to metal pipes and rubber hoses. However, such hoses are used in high-temperature environments for long periods of time. Recently, there has been a trend toward requiring hoses to have durability in high-temperature environments of 100°C or higher, and there is room for improvement in terms of improving the durability of hoses in high-temperature environments. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-155793 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a resin material for a hose, which is used mainly for an air conditioner hose mounted on a vehicle and has improved durability in a high-temperature environment, and to provide said hose. [Means for solving the problem]

[0007] In order to achieve the above object, the resin material for hoses of the present invention has a breaking elongation of 50% or more under a specified temperature environment condition of 100°C to 150°C, and a plasticizer content of 3% by mass or less based on the total mass. , the 10% modulus under the environmental conditions of the specified temperature is 3 MPa or less It is characterized in that:

[0008] The hose of the present invention is characterized in that the above-mentioned resin material for a hose is It is formed into a cylindrical shape It is characterized in that it is used as a component member. Effect of the Invention

[0009] According to the resin material for hoses of the present invention, the breaking elongation is 50% or more under a predetermined environmental temperature condition of 100°C or more and 150°C or less. Therefore, even if the hose is used in a high temperature environment of 100°C or more, it is possible to ensure durability that can withstand practical use. In addition, the content of plasticizer relative to the total mass of the resin material is very small, or no plasticizer is contained. Since plasticizer gradually disappears from the resin material over time, the higher the content, the more significant the change in physical properties of the resin material over time. Since the resin material for hoses of the present invention does not substantially contain plasticizer, the change in physical properties over time is suppressed, which is advantageous for maintaining durability in a high temperature environment for a long period of time.

[0010] According to the hose of the present invention, deterioration over time of the physical properties of the components of the hose is suppressed even when used under high temperature conditions, so that good durability can be maintained for a long period of time. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is an explanatory diagram illustrating an air conditioner equipped with a hose of the present invention in a plan view. [Diagram 2]FIG. 2 is an explanatory diagram illustrating the hose of FIG. 1 with a part cut away. [Diagram 3] FIG. 3 is a cross-sectional view of the hose of FIG. 2. [Figure 4] FIG. 11 is a partially cutaway explanatory view illustrating another embodiment of the hose. [Diagram 5] FIG. 5 is a cross-sectional view of the hose of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a resin material for a hose and a hose according to the present invention will be described based on embodiments shown in the drawings.

[0013] The hose 1 of the present invention shown in Fig. 1 is used in an air conditioner 6 (hereinafter referred to as air conditioner 6) mounted on an automobile 7. This hose 1 can be used not only in automobiles 7, but also in air conditioners 6 mounted on other types of vehicles such as heavy construction machinery vehicles and agricultural vehicles. The inner diameter of the hose 1 is, for example, 2.0 mm or more and 52.0 mm or less.

[0014] The air conditioner 6 is placed in an engine room 8 which is subject to high temperatures. Components 6A, 6B, 6C, and 6D of the air conditioner 6 are connected by a hose 1 to form a circulation path for circulating a refrigerant C. The components 6A to 6D include a compressor, a condenser, a separation dryer, an expansion valve, and an evaporator. The air conditioner 6 is equipped with other components as required. Examples of the refrigerant C include HFC-134a and HFO-1234y.

[0015] 2 and 3, the hose 1 has a hose wall formed from the hose resin material M of the present invention (hereinafter referred to as resin material M). That is, a cylindrical body formed from this resin material M into a cylindrical shape serves as a constituent member of the hose 1. More specifically, the inner surface layer 2, intermediate layer 4, and outer surface layer 5 of the hose 1 are formed from the resin material M. The intermediate layer 4 is not essential and can be provided arbitrarily as necessary.

[0016] The resin material M has a resin component, or a resin component and a small amount of plasticizer. Here, the resin component does not necessarily mean that it is entirely resin, but also includes cases where part of it is elastomer or rubber. The resin component may be only one type of resin, or may be a blend of multiple types of resin. In addition, the resin material M may contain flame retardants, anti-aging agents, colorants, etc., within the range that does not decrease the breaking elongation of 50% under the environmental condition of a specific temperature T described later.

[0017] The content of the plasticizer is 3% by mass or less, preferably 2% by mass or less, and more preferably 1% by mass or less or 0% by mass, based on the total mass of the resin material M. In other words, the resin material M is substantially free of plasticizer. The minimum amount of plasticizer required to ensure the plasticity required for injection or extrusion of the resin material M can be blended.

[0018] The inner surface layer 2 is a portion that comes into direct contact with the flowing fluid, and is the innermost layer of the hose 1. The outer surface layer 5 is a portion that is exposed to the outside, and is the outermost layer of the hose 1. The intermediate layer 4 is interposed between the inner surface layer 2 and the outer surface layer 5. That is, the inner surface layer 2, the intermediate layer 4, and the outer surface layer 5 are laminated coaxially in that order from the inner periphery side.

[0019] The hose 1 further has reinforcing layers 3 interposed between the inner layer 2 and the intermediate layer 4, and between the intermediate layer 4 and the outer layer 5. In this embodiment, the reinforcing layer 3 has a braided structure in which the reinforcing wires 3a are braided, but a reinforcing layer 3 having a spiral structure in which the reinforcing wires 3a are wound in a spiral shape can also be used. Examples of the reinforcing wires 3a include non-metallic wires such as resin fibers and natural fibers, such as polyester, nylon, polyurethane, acrylic, polyvinyl chloride, rayon, cupra, polynosic, cotton, and aramid, and metal wires such as steel and steel wire. The specifications and arrangement density of the reinforcing layers 3 are determined mainly based on the internal pressure resistance required for the hose 1. In the hose 1, adjacent layers are joined together to be integrated.

[0020] This resin material M has a property of having a breaking elongation of 50% or more under environmental conditions of a predetermined temperature T of 100°C or more and 150°C or less. This predetermined temperature T is preferably set differently depending on the part of the hose in which the resin material M is used; for example, it is set to 100°C, more preferably 120°C, for the inner layer 2, and 135°C, more preferably 150°C, for the outer layer 5. When the hose internal pressure (operating internal pressure) is 3.9 MPa or more, it is preferable that the inner layer 2 and the outer layer 5 are formed from resin materials M of different specifications. Note that the predetermined temperature T for the intermediate layer 4 is set to the same temperature as that for the inner layer 2, but may also be set to the same temperature as that for the outer layer 5 depending on the operating conditions of the hose 1.

[0021] In cases where the predetermined temperature T is not varied for each part of the hose, such as when the hose internal pressure (operating internal pressure) is less than 3.9 MPa, the predetermined temperature T is set, for example, to 135° C., and more preferably to 150° C. In other words, when the inner surface layer 2 and the outer surface layer 5 are formed from the resin material M of the same specifications, it is advisable to set the predetermined temperature T to 135° C. or 150° C.

[0022] If the breaking elongation is less than 50%, sufficient durability as the hose 1 cannot be ensured, and it is more preferable to set it to 100% or more. Since making the breaking elongation larger than necessary will only result in over-specification, the upper limit of the breaking elongation is 500%, and more preferably 300%. This breaking elongation is a value measured in accordance with the method specified in JIS K6251:2017. In more detail, this breaking elongation is the elongation when a dumbbell-shaped No. 6 test piece of the resin material M is pulled at a speed of 50 mm / min and the test piece breaks, and is expressed as a ratio (%) to the test length of the test piece before the test.

[0023] To obtain a resin material M that does not substantially contain a plasticizer and has a breaking elongation of 50% or more at a predetermined temperature T, for example, it is preferable to manufacture the resin material M by blending a thermoplastic resin with an elastomer (or rubber). It is preferable to use an alloy material with an island-sea structure in which the thermoplastic resin is the sea and the elastomer (or rubber) is the island for the resin material M.

[0024] For example, alloy materials are manufactured with a number of different blending ratios of elastomer (or rubber) to thermoplastic resin, and the blending ratio of elastomer (or rubber) in the alloy material that satisfies the property of breaking elongation of 50% or more at a specified temperature T is determined. In this way, an appropriate range of the blending ratio of elastomer (or rubber) to thermoplastic resin is determined. Then, within this appropriate range, the blending ratio of elastomer (or rubber) to thermoplastic resin is determined, taking into consideration other requirements (breaking strength, 10% modulus, etc.) described later. By using such an alloy material with a sea-island structure as the resin material M, it becomes easier to achieve both the property of breaking elongation of 50% or more at a specified temperature T and the property of 10% modulus of 3 MPa or less described later.

[0025] Examples of thermoplastic resins used for the resin material M include polyamide, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl acetate, polyurethane, Teflon (registered trademark), ABS resin, AS resin, acrylic resin, polyacetal, polycarbonate, modified polyphenylene ether, polyester, polyphenylene sulfide, polytetrafluoroethylene, polysulfone, polyethersulfone, amorphous polyarylate, liquid crystal polymer, polyetheretherketone, polyamideimide, polyvinyl alcohol, and ethylene-vinyl alcohol copolymer.

[0026] Examples of the elastomer used in the resin material M include olefin-based thermoplastic elastomers, styrene-based thermoplastic elastomers, ethylene-unsaturated carboxylic acid ester copolymers, polyamide elastomers, polyester elastomers, and modified products thereof.

[0027] Examples of rubber used in the resin material M include natural rubber, styrene-butadiene rubber, butadiene rubber, butyl rubber, ethylene-propylene-diene rubber, nitrile rubber, acrylic rubber, silicone rubber, fluororubber, and modified products thereof.

[0028] Examples of the plasticizer include phthalates, trimellitates, adipates, phosphates, benzoates, epoxidized vegetable oils, polyhydric alcohols, polyhydric alcohol esters, and butylbenzenesulfonamide.

[0029] An example of a typical compounding and compounding ratio of resin material M is 100 parts by weight of brominated butyl rubber per 100 parts by weight of polyamide resin, or 100 parts by weight of acid-modified ethylene-α-olefin copolymer elastomer per 100 parts by weight of ethylene-vinyl alcohol copolymer resin.

[0030] Furthermore, the resin material M preferably has a breaking strength of 5 MPa or more under the environmental condition of a predetermined temperature T. If the breaking strength is less than 5 MPa, it becomes difficult to sufficiently resist a force when the force acts suddenly and / or locally on the hose 1, and therefore the breaking strength is more preferably 8 MPa or more. Since making the breaking strength larger than necessary would only result in over-spec, the upper limit of the breaking strength is, for example, 20 MPa. The breaking strength is the value obtained by dividing the maximum tensile force recorded when the test piece is pulled until it breaks in the above-mentioned breaking elongation measurement, by the cross-sectional area of ​​the test piece before the test.

[0031] The resin material M preferably has a 10% modulus of 3 MPa or less under the environmental condition of a predetermined temperature T. If the 10% modulus exceeds 3 MPa, the flexibility of the hose 1 is insufficient. In addition, if the 10% modulus exceeds 3 MPa, the vibration damping effect of the hose 1 against vibrations caused by the component equipment 6A and the like is impaired.

[0032] Since the hose 1 used in the air conditioner 6 mounted on the automobile 7 is often installed and used within a range of elongation of about 10%, it is advisable to set an appropriate range of the 10% modulus in this manner. The lower limit of this 10% modulus is, for example, 1 MPa. This 10% modulus is the value obtained by dividing the tensile force when the above test piece is elongated by 10% by the cross-sectional area of ​​the test piece before the test.

[0033] Since the hose 1 may be used in a high-temperature environment of 100° C. or more, the resin material M preferably contains a resin having a melting point of 170° C. to 230° C., more preferably 180° C. to 210° C., and is mainly composed of a material having this melting point. The resin material M preferably contains polyamide (nylon 11, 12, etc.).

[0034] Since the inner surface layer 2 comes into direct contact with the refrigerant C, an appropriate resin is used that has a breaking elongation of 50% or more under environmental conditions at a specified temperature T while taking into consideration factors such as durability against the refrigerant C. For example, an alloy material of polyamide and a rubber-based material is used. When HFO-1234y is used as the refrigerant C, the impermeability to the refrigerant C can be improved by using an alloy material of a nylon-based resin and a bromine-based isobutylene-paramethylstyrene copolymer for the inner surface layer 2.

[0035] For the outer layer 5, an appropriate resin is used that has a breaking elongation of 50% or more under environmental conditions of a specific temperature T while taking into consideration resistance to external damage and weather resistance. For example, an alloy material of polyamide and thermoplastic polyester elastomer (TEEE) is used.

[0036] In resin materials containing plasticizers, the plasticizer blooms over time and gradually disappears from the resin material. As a result, the properties of the resin material (particularly flexibility and elongation) change over time. Therefore, when a hose 1 is formed using such a resin material, it becomes difficult to ensure good durability over a long period of time, particularly for a hose 1 used in a high-temperature environment. Furthermore, the higher the content of plasticizer in the resin material, the more significant the change in the physical properties of the resin material over time becomes.

[0037] In order to avoid the above-mentioned disadvantages caused by plasticizers, the resin material M of the present invention is designed to contain only a small amount of plasticizer or no plasticizer at all. Therefore, this resin material M is advantageous in that the change in physical properties over time is suppressed and durability in high-temperature environments can be maintained for a long period of time. As a result, it is possible to maintain the breaking elongation at 50% or more in a high-temperature environment at a predetermined temperature T for a long period of time.

[0038] Furthermore, because this hose 1 is formed using resin material M, it can maintain good durability for a long period of time even under high temperature operating conditions. Since resin material M has a breaking elongation of 50% or more in a high temperature environment of predetermined temperature T, hose 1 can be bent appropriately and connected to components 6A-6D for long-term use, even in a narrow engine room 8.

[0039] Furthermore, since the hose 1 has lower thermal conductivity than metal pipes or rubber hoses, it is advantageous in suppressing the temperature rise in the engine compartment 8 due to the heat released from the hose 1. This has the effect of lowering the external environmental temperature of the hose 1.

[0040] In order to maintain excellent durability for a long period of time, it is most ideal for all of the resin layers constituting the hose 1 (in this embodiment, the inner layer 2, the intermediate layer 4 and the outer layer 5) to be formed using a resin material M that has a breaking elongation of 50% to 500%, a breaking strength of 5 MPa or more, a 10% modulus of 3 MPa or less and a plasticizer content of zero under the environmental conditions of a predetermined temperature T of 150° C. Furthermore, it is preferable that the outer layer 5 is formed from a resin material M that has a breaking elongation greater than that of the inner layer 2 at the predetermined temperature T (150° C.).

[0041] The embodiment of the hose 1 illustrated in Figures 4 and 5 has an inner surface layer 2 and an outer surface layer 5 laminated coaxially. The inner surface layer 2 and the outer surface layer 5 are formed of a resin material M. The outer peripheral surface of the inner surface layer 2 and the inner peripheral surface of the outer surface layer 5 are joined together to form an integrated body. As described above, the inner surface layer 2 and the outer surface layer 5 are preferably made of the resin material M having an elongation of 50% or more at different predetermined temperatures T.

[0042] In this hose 1, reinforcing material 3b is dispersed and embedded only in the outer layer 5. This reinforcing material 3b is a nonmetallic short fiber, and improves the internal pressure resistance of the hose 1. For example, glass fiber or carbon fiber is used as the reinforcing material 3b. The specifications of the reinforcing material 3b and the mixing ratio in the outer layer 5 are determined mainly based on the internal pressure resistance required for the hose 1.

[0043] The hose 1 can also be applied to the various specifications and arrangements described in the previous embodiments. [Explanation of symbols]

[0044] 1 Hose 2. Inner layer 3 Reinforcement layer 3a Reinforcement wire 3b Reinforcement material 4. Middle Tier 5 Outer layer 6 Air conditioner (air conditioner) 6A, 6B, 6C, 6D components 7. Automobiles 8. Engine Room M Hose Resin Material C Refrigerant

Claims

1. A resin material for hoses, characterized in that the breaking elongation under environmental conditions of a specified temperature of 100°C or more and 150°C or less is 50% or more, the plasticizer content is 3 mass% or less with respect to the total mass, and the 10% modulus under environmental conditions of the specified temperature is 3 MPa or less.

2. A resin material for hoses as described in claim 1, having a 10% modulus of 1 MPa or more under environmental conditions of the specified temperature.

3. 3. The resin material for a hose according to claim 1, wherein the breaking elongation under said predetermined temperature environment condition is 500% or less, and the breaking strength under said predetermined temperature environment condition is 5 MPa or more.

4. 4. The resin material for a hose according to claim 1, comprising a resin having a melting point of 170° C. or higher and 230° C. or lower.

5. The resin material for a hose according to any one of claims 1 to 4, which contains a polyamide.

6. A hose comprising the resin material for a hose according to any one of claims 1 to 5 as a structural member formed into a cylindrical shape.

7. 7. The hose according to claim 6, wherein the hose resin material formed into a cylindrical shape is used as an inner layer and an outer layer.

8. A hose as described in claim 7, wherein the internal pressure of the hose is 3.9 MPa or more, and the specifications of the hose resin material used in the inner layer and the outer layer are different, the specified temperature being set to 120°C for the hose resin material used in the inner layer and the specified temperature being set to 150°C for the hose resin material used in the outer layer.

9. A hose as described in claim 7, wherein the internal pressure of the hose is less than 3.9 MPa, the specifications of the hose resin material used in the inner layer and the outer layer are the same, and the specified temperature is set to 135°C or 150°C.

10. 10. The hose according to claim 7, which connects components of an air conditioner mounted in a vehicle to allow a refrigerant to flow therethrough.

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