JPH0156311B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automobile water hose that is suitably used as a heater hose, radiator hose, etc. (Prior art) Conventionally, this type of hose has been used to connect the engine part and the radiator part in order to cool the engine part of a car, and the radiator hose used for the purpose of circulating cooling water, and the hose used to connect the engine part and the fan part. There are heater hoses, etc. that connect the heater part and are used for the same purpose, and in addition to heat resistance and antifreeze resistance, they have flex resistance, etc. because they are bent and piped inside the limited engine room. characteristics are required. As a result, the inner and outer tubes of the hose are heat resistant,
Ethylene-propylene-conjugated diene copolymer rubber (hereinafter referred to as "EPDM") with excellent antifreeze resistance
A water hose (hereinafter referred to as "hose") that is made of a compound and has a reinforcing layer placed between the inner and outer tubes and braided (braided or spiral) with rayon thread or nylon thread. is publicly known. (Problem to be Solved by the Invention) However, in hoses using rayon yarn as reinforcing yarn, rayon yarn has poor heat resistance (deteriorates in dry heat and wet heat) However, there is a problem that the service life is short. On the other hand, in a hose using nylon thread as a reinforcing thread, the nylon thread satisfies the above-mentioned required characteristics, so the necessary conditions for maintenance-free construction are met. However, for such hoses, a method of spirally braiding nylon threads is usually adopted from the viewpoint of manufacturing efficiency and cost. This poses a serious problem in that the threads may come off due to such problems as the hoses may fall out, the pressure resistance may decrease, and in the worst case, the hose may burst. Therefore, in order to prevent such threads from coming off, the nylon threads are coated with RFL (resorcinol-formalin-latex).
Means for treating and bonding the inner and outer tubes intermediately has been proposed. However, in hoses using RFL-treated nylon threads, the threads are sticky immediately after RFL treatment, which tends to cause problems during braiding, and not only is manufacturing efficiency inferior, but the RFL-treated The threads are hardened, and combined with deterioration (decreased strength) due to dry heat or wet heat, thread breakage occurs due to pulsating motion of the hose (expansion and contraction movement in the radial direction of the hose) caused by bending and repeated hydraulic shocks, resulting in hose rupture. There is a danger of this. The present invention was invented based on the above circumstances, and provides a hose that is excellent in heat resistance and antifreeze resistance, and also has excellent bending resistance and hydraulic shock resistance, and can be made maintenance-free. The purpose is to (Means for Solving the Problems) The present invention has a nylon spiral braided reinforcing layer embedded in an adhesive layer applied on an inner tube made of an EPDM compound, and further provided on the outer surface of the adhesive layer.
The gist of the present invention is a hose having an outer tube made of EPDM, in which the adhesive layer is made of a rubber adhesive made by mixing EPDM with chlorinated rubber. The configuration of the present invention will be explained in detail below. The EPDM compounds constituting the inner and outer tubes of the present invention include known compounded chemicals, vulcanizing agents, vulcanization accelerators, reinforcing agents, fillers, softeners, processing aids, and anti-aging agents commonly used for EPDM. Agents, etc. are mixed and used. Nylon filament twists are used as the nylon spiral braided reinforcing layer in the present invention. As the nylon, nylon 6,6 is preferred in terms of heat resistance and abrasion resistance, and as for the yarn structure, filament twisted yarn is more preferred than spun yarn in terms of strength, flexibility, and cost. In addition, the diameter of filament twisted yarn is 50~
300μ is used. Furthermore, the filament twisted yarn is not subjected to RFL treatment, but merely subjected to moist heat treatment for the purpose of removing permanent elongation of the yarn. The moist heat treatment is performed at 120-150°C for 10-60 minutes in a steam atmosphere. At that time, whether or not to load the tension, or if the tension is loaded, to what degree the load should be set is selected as appropriate. Further, the spiral braid angle of the nylon thread is usually a resting angle (approximately 110°), but it can be changed as appropriate in consideration of pressure resistance, flexibility (flexibility), etc. The adhesive layer in the present invention is formed using a solvent-type rubber adhesive made by mixing EPDM with chlorinated rubber. This rubber adhesive can be prepared by mixing a solution of an EPDM compound (co-glue) with a solution of chlorinated rubber in an appropriate ratio. In the present invention, for example, the same type of co-glue and chlorinated rubber solution are prepared, and these are mixed at a mixing ratio (wt ratio) of co-glue/chlorinated rubber solution.
It is adjusted to have a ratio of 95/5 to 50/50, preferably 90/10 to 70/30. In addition, from the viewpoint of workability, etc., the rubber adhesive has a solid content of 5 to 30 wt% and a viscosity of 50 to 2000 centipoise (measured at 25°C). completely covers the reinforcing layer,
It is sufficient that the reinforcing layer is embedded in the rubber adhesive layer, and the thickness is in the range of 10 to 100 μm. The rubber adhesive as described above in the present invention is
It prevents the threads from coming apart immediately after braiding, and also moderately restricts the movement of the threads when used as a hose, and prevents the threads from rubbing against each other due to pulsating motion due to repeated hydraulic shocks or vibrations from the engine. It also has the effect of preventing the thread from coming off from the end of the hose. (Example) Next, the present invention will be specifically described based on an example. In the following comparative examples and examples, EPDM
First, the compound is extruded as an inner tube using an extruder, and then each fiber thread is braided under the conditions shown in Table 1 (in the example, a rubber adhesive is further applied after braiding), and an inner tube is formed on the outside. An EPDM compound made of the same material as the outer tube was extruded and coated. This was rolled into a long length or short length, and vulcanized in a steam can at 150°C for 30 minutes to produce a hose with an inner diameter of 16 mm and an outer diameter of 24 mm. Various performance evaluations were then conducted using these hoses. The results are also listed in Table-1. The hose performance evaluation method is as follows. (1) Adhesion A part of the outer tube of the hose was peeled off, the reinforcing thread was taken out, and the reinforcing thread was pulled out in an approximately tangential direction to the outer circumference of the hose using an autograph (pulling speed: 250 mm/min) to measure the pulling force. (2) Heat resistance Water/ethylene glycol in hose = 50/50
(volume ratio), and after aging in an atmosphere of 125℃ for a predetermined time, apply internal pressure to the hose.
The burst pressure of the hose was measured. The data are expressed as the hose burst pressure retention rate (%) relative to the Planck product. (3) Flexibility Connect both ends of a 200mm long hose to the connecting pipe, water/ethylene glycol = 50/50 (volume ratio)
An antifreeze solution with the following composition is sealed in a hose and aged at 125°C for a predetermined period of time. After that, the filled liquid was extracted, one end of the hose was fixed, and the other end was repeatedly moved 35 mm downward from the horizontal position.
After performing the bending test 10,000 times, internal pressure was applied to the hose and its bursting pressure (at room temperature) was measured. The data are expressed as the hose bursting pressure retention rate [%] relative to the blank. The joint between the hose and the connecting pipe is tightened with a clamp (tightening torque: 15 kg/cm). (4) Hydrostatic impact resistance As shown in Figure 1, connect the curved hose with a connecting pipe by tightening the clamp (tightening torque 15 kg cm), and water/ethylene glycol = 50/50 (volume ratio).
We circulated an antifreeze solution with the following composition and applied water pressure shock repeatedly 6 times/minute at a liquid temperature of 95℃ and an ambient temperature of room temperature (no heating), and checked the condition of the thread coming out from the end of the hose and the presence or absence of a hose rupture. Examined. The fluid pressure of the circulating fluid was 7 Kg/cm ² . The data are expressed as the number of hydraulic shocks at which thread pull-out or hose rupture occurs. (Reference to JASOM302-76) As is clear from the results in Table 1, in Comparative Example 1, the rayon yarn itself has poor heat resistance, causing yarn breakage and insufficient durability. In addition, in Comparative Example 2, the nylon yarn was not subjected to any treatment that causes yarn hardening such as RFL treatment, so the heat resistance and bending resistance were good, but there was no means to restrain the nylon yarn from coming off. Repeated water pressure shocks cause the thread to come off and cause the hose to burst. In addition, in Comparative Example 3, since the nylon thread was subjected to RFL treatment, the thread itself was in a hardened state and the thread deteriorated due to heat aging, causing thread breakage or breakage, and sufficient durability could not be obtained. do not have. On the other hand, in each of the examples, the nylon yarn was not subjected to any treatment that would cause yarn hardening or yarn deterioration, such as RFL treatment, and the flexibility and strength of the yarn were well maintained even in a high temperature atmosphere. Even in the case of repeated water pressure shocks when the hose is arranged in a bent pipe, the thread coming off is prevented or suppressed, and the hose does not burst. In addition, in the hose of the present invention, the reinforcing yarn is not subjected to any special treatment such as RFL treatment, so the yarn itself does not become sticky, and therefore there is no problem during braiding (the yarn is not sticky). If this occurs, the frictional resistance between the yarn and the yarn guide of the braiding machine will increase, resulting in increased resistance when feeding the yarn, excessive tension will be applied to the yarn, and the hose will be deformed or the braid will be disturbed. ) It also has the advantage of being able to be manufactured continuously and efficiently. (Effects of the Invention) As explained in detail above, the hose of the present invention has the following features:
Since the outer tube is made of an EPDM compound, it has excellent heat resistance and antifreeze resistance, and the reinforcing layer is spirally braided with nylon threads and is made of a specific rubber adhesive. Since it is embedded in the layer, yarn deterioration is suppressed, and it also has excellent bending resistance and hydraulic impact resistance. Therefore, according to the present invention, it is possible to provide a water hose for an automobile that can be made maintenance-free. 【table】

[Brief explanation of drawings]

FIG. 1 is a partial side view schematically showing an apparatus for a hydraulic impact performance test to explain the present invention. 1... Hose, 2... Connection pipe, 3... Clamp, 4... Circulating fluid (antifreeze).

Claims (1)

[Scope of Claims] 1. A nylon spiral braided reinforcing layer is embedded in an adhesive layer formed on an inner tube made of a blend of ethylene-propylene-conjugated diene copolymer rubber, and a nylon spiral braided reinforcing layer is further embedded in the adhesive layer. In an automobile water hose having an outer tube made of a blend of ethylene-propylene-conjugated diene copolymer rubber on the outer surface, the adhesive layer is formed by adding chlorinated rubber to the ethylene-propylene-conjugated diene copolymer rubber. An automobile water hose characterized by being formed from a mixed rubber adhesive.