JPH027053Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Industrial Application Field) The present invention relates to a refrigerant transport hose that is suitably used as an automobile cooler hose and has excellent flexibility even after heat aging. (Problems to be solved by conventional techniques and inventions) A typical example of a hose for transporting refrigerant is a cooler hose for an automobile. The characteristics required of such a hose include low permeability to refrigerant gas, low penetration of water from the outside, flexibility, resistance to kinking, low cost, and easy installation. In addition to the above, there has recently been a need for weight reduction, and for this reason, instead of a rubber hose in which both the inner and outer tubes are made of rubber, we have developed a resin-rubber composite hose in which the inner tube is made of resin and the outer tube is made of rubber. Hose is suggested. Such resin-rubber composite hoses have an inner tube made of a synthetic resin such as polyamide resin that is highly resistant to refrigerant and gas permeability, and the outer surface is usually braided at a resting angle (approximately 55 degrees) to maintain pressure resistance. It is well known to have a reinforced fiber reinforced layer and a rubber outer tube with excellent weather resistance on its outer surface. However, such hoses tend to be manufactured by increasing the thickness and number of braided yarns used in the reinforcing layer in order to withstand high pressure, and the flexibility of the hose is often impaired. . Furthermore, in order to prevent the braided yarns from becoming disordered, the reinforcing layer of such hoses is fixed to the inner tube with an adhesive or the like, so even if the hose has not been subjected to heat aging immediately after manufacture, it will not bend or deform when the hose bends. Since the reinforcing layer acts to strongly prevent bending deformation of the inner tube, there is a drawback that flexibility is poor and kinks are likely to occur. Furthermore, due to the lack of flexibility, it is difficult to form a bent tube in terms of manufacturing, and it is also difficult to install it in a narrow, limited space. On the other hand, in the hose having the above structure, it is also known that an intermediate rubber layer is provided between the inner tube and the fiber-reinforced layer for the purpose of adhering the inner tube and the fiber-reinforced layer or the outer tube. However, such hoses are not intended to maintain good flexibility after heat aging;
The rubber material used for the intermediate rubber layer is often limited by the materials of the inner tube, fiber reinforced layer, outer tube, etc. Due to these circumstances, conventional hoses are
Although it has excellent flexibility during manufacturing and early use (when it has not undergone much heat aging), if it undergoes considerable heat aging (thermal history) during long-term use, the hose will harden and lose its flexibility. The hose is easily damaged and broken during maintenance, which not only poses a problem in terms of durability, but also causes the problem of vibration and noise generation as the hose itself hardens. (Means for Solving the Problems) The present invention was made to solve the above problems, and its gist is to solve the problems described above. In a refrigerant transport hose with a reinforcing layer provided, excellent flexibility is maintained even after heat aging by providing an intermediate rubber layer configured as shown in B below between the inner tube and the reinforcing layer. It is in. (A) A synthetic resin selected from polyamide resin, saponified ethylene-vinyl acetate copolymer resin, and vinyl chloride-vinylidene chloride copolymer resin. (B) A rubber compound of any one of ethylene-propylene-diene rubber, chlorosulfonated polyethylene rubber, and chlorinated polyethylene rubber. (Function) In the present invention, since the intermediate rubber layer is interposed between the resin inner tube and the reinforcing layer to allow relative displacement thereof, the flexibility of the refrigerant transport hose is increased. This also makes it easier to form the refrigerant transport hose as a bent tube, and thus also makes it easier to fit the hose into a limited narrow space. Furthermore, the ethylene-propylene-diene rubber, chlorosulfonated polyethylene rubber, and chlorinated polyethylene rubber used as the intermediate rubber layer in the present invention are all rubbers with excellent heat resistance, and do not harden or deteriorate even when subjected to heat history. Because of the small amount, the hose does not lose its flexibility even after long-term use under the influence of heat. This prevents the hose from breaking during maintenance and from generating vibration noise due to hardening of the hose. As mentioned above, the present invention was developed based on the idea of ensuring flexibility in a refrigerant transport hose by preventing thermal deterioration of the intermediate rubber layer itself. However, it is unknown how much heat resistance the intermediate rubber layer should have to ensure flexibility, and if a rubber material with more heat resistance than necessary is used, the product will be of excessive quality and cost will increase. only becomes high. In addition, as an intermediate rubber layer of a refrigerant transport hose,
There are other problems with Freon permeation resistance and water permeation resistance. Through various tests and research, the inventor of the present invention was able to confirm that the above-mentioned ethylene-propylene-diene rubber, chlorosulfonated polyethylene rubber, and chlorinated polyethylene rubber can satisfy all of these characteristics. It was completed. Note that the problem of water permeability here refers to the following problem. That is, in general, in the case of a refrigerant transport hose having a resin inner tube, these outer tubes, A large number of fine holes penetrating the reinforcing layer in the radial direction are formed using a needle or the like, but in this case, a problem arises in that moisture from the outside enters the inside of the hose through these fine holes. If the water permeability of the intermediate rubber layer is poor, a problem arises in that moisture passes through the intermediate rubber layer and enters the interior. Therefore, the intermediate rubber layer of such a refrigerant transport hose is required to have water permeation resistance that is better than a certain level. In this way, for refrigerant transport hoses, the intermediate rubber layer has not only heat resistance but also Freon permeation resistance,
It is necessary to have excellent water permeability, and therefore, if only heat resistance is considered, it is possible to use acrylic rubber, epichlorohydrin rubber, etc. as the intermediate rubber layer, but these have properties other than heat resistance. Because of its inferiority, it is actively excluded in this invention. Only the above-mentioned ethylene-propylene-diene rubber, chlorosulfonated polyethylene rubber, and chlorinated polyethylene rubber can achieve the object of the present invention. (Example) Next, an example of the present invention will be described in detail based on the drawings. The inner tube 1 is made of polyamide resin (nylon 6, nylon 6,6, modified nylon such as nylon 6/ethylene-propylene-diene copolymer, etc.) or ethylene-vinyl acetate copolymer resin, which has excellent refrigerant gas permeability. Synthetic resins such as saponified resins and vinyl chloride-vinylidene chloride copolymer resins are used, but preferably nylon 6/
Ethylene-propylene-diene copolymer is good.
In addition, the wall thickness is usually made to be 0.1 to 1.5 mm, but if it falls outside this range at the lower limit, it will not only take on a film-like appearance, but will also be difficult to manufacture as a hose inner tube.
It has poor refrigerant gas permeability, and if it deviates from the upper limit, flexibility will be impaired. The middle rubber layer 2 is made of ethylene-propylene-diene rubber (EPDM), which has excellent water permeability and heat resistance.
A rubber compound of any of the following is used: butyl rubber (hereinafter abbreviated as IIR), chlorosulfonated polyethylene rubber (hereinafter abbreviated as CSM), and chlorinated polyethylene rubber (hereinafter abbreviated as CPE). The hardness of the rubber compound is 50° to 75° (JIS-A
hardness) is preferred. If this range is exceeded at the lower limit, the reinforcing layer 3 provided on the outer surface of the intermediate rubber layer 2 will sink into the intermediate rubber layer 2 and act to restrain the bending deformation of the inner tube when the hose is bent. It loses flexibility and if it comes off at the upper limit,
The intermediate rubber layer 2 itself becomes hard, impairing the flexibility of the hose. Furthermore, the thickness of the intermediate rubber layer 2 is made to be 0.5 to 3.0 mm, but if this range is exceeded at the lower limit, the reinforcing layer 3 applied thereon will have a large force restraining the bending deformation of the inner tube 1. This will impair the flexibility of the hose, and if it comes off at the upper limit, the weight will increase. The outer tube 4 is usually made of a rubber compound with excellent weather resistance and heat resistance, and its wall thickness is appropriately determined depending on the thickness of the intermediate rubber layer 2. The hardness used is in the range of 50° to 85°. The reinforcing layer 3 is made of natural fibers or synthetic fibers such as vinylon, polyamide, polyester, etc., which are braided (braided or spiral) on the outer surface of the intermediate rubber layer 2.
and configured. The braid angle is usually braided at a resting angle considering pressure resistance, and the braid density is also relatively dense (for example, 60-100%) when pressure resistance is considered.
However, it can be arbitrarily selected and used depending on the purpose, use, etc. However, the feature of the present invention is that even when the reinforcing layer 3 is densely braided at a resting angle in consideration of pressure resistance, it maintains excellent flexibility, especially even after heat aging. This is where the practical value of the present invention is greatly recognized. Further, such a hose according to the present invention is manufactured as follows. First, the inner tube 1 is extruded onto a mandle, and an adhesive is applied to its outer surface. Next, apply the intermediate rubber layer 2 to the inner tube 1.
The outer surface is coated, another adhesive is applied to the outer surface, and the reinforcing layer 3 is braided. Furthermore, the outer tube 4 is coated on the outer surface of the reinforcing layer 3. Then, the outer surface of the outer tube 4 is leaded and integrally vulcanized and bonded to obtain a desired hose. According to the refrigerant transport hose of the present invention described in detail above, a specific intermediate rubber layer 2 having excellent refrigerant gas permeability and water permeability resistance as well as heat resistance is provided between the inner tube 1 and the reinforcing layer 3. Therefore, the intermediate rubber layer 2 acts to effectively buffer the reinforcing layer 3 from restraining the bending deformation of the inner pipe 1 when the hose is bent, thereby increasing the flexibility of the hose. . Moreover, even if the hose undergoes heat aging (thermal history), the intermediate rubber layer 2 hardly hardens and deteriorates, so it maintains the same excellent flexibility as before use (before heat aging) for a long period of time. Moreover, problems of vibration and noise do not occur. In particular, as mentioned above, the feature of the present invention is that the above-mentioned effects can be achieved even when the reinforcing layer 3 is braided at a resting angle and with high density in consideration of pressure resistance. In addition to the advantages, it also has practical effects such as easier installation (bent tube formation is also possible, which further simplifies installation). Next, the effects of the present invention will be demonstrated using examples. A hose constructed as shown in Table 1 was manufactured and its flexibility was evaluated. The results are also shown. The flexibility was evaluated by fixing one end of a specified length of hose with the horizontal cut surface on the board, bending the hose with the other end, and measuring the amount required to bring the horizontal cut surface of the other end into close contact with the board. This was done by measuring the bending load. Measurements were made on blank products and heat aged products (aged at 120℃,
140℃ aging). As is clear from the above examples, it has been demonstrated that the product of the present invention maintains flexibility not only before heat aging, but also even after long-term heat aging, to the same degree as before heat aging. Ta. Furthermore, this product has excellent properties such as refrigerant gas permeability, water permeability, and pressure resistance.

【table】 There is no problem in use.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention. 1: Inner tube, 2: Intermediate rubber layer, 3: Reinforcement layer, 4:
outer tube.

Claims (1)

[Scope of Claim for Utility Model Registration] In a refrigerant transport hose in which a reinforcing layer is provided between a synthetic resin inner tube and a rubber outer tube configured as described in A below, the following B is provided between the inner tube and the reinforcing layer. A hose for transporting a refrigerant, characterized in that it retains excellent flexibility even after heat aging by providing an intermediate rubber layer composed of. (A) A synthetic resin selected from polyamide resin, saponified ethylene-vinyl acetate copolymer resin, and vinyl chloride-vinylidene chloride copolymer resin. (B) A rubber compound of any one of ethylene-propylene-diene rubber, chlorosulfonated polyethylene rubber, and chlorinated polyethylene rubber.