JPH09136364A - High-pressure flexible hose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible high-pressure hose having excellent durability. SOLUTION: The high-pressure flexible hose comprises at least an inner tube, a reinforcing fiber layer and an outer tube, wherein the inner tube is formed of thermoplastic elastomer that the vulcanized composition of acryl group-containing rubber is dispersed in polyester thermoplastic resin, and the fiber layer that organic fiber is adhered to the outside via dealcoholizing type or deoxime type condensed ambient temperature curable silicone rubber adhesive is disposed at the outside. Further, the outer tube formed of thermoplastic elastomer that vulcanized rubber is dispersed in the thermoplastic resin is disposed thereon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible and durable high-pressure hose made of a thermoplastic elastomer.

[0002]

2. Description of the Related Art A rubber hose usually consists of an inner pipe, a reinforcing layer and an outer pipe, and the inner pipe and the outer pipe are made of vulcanized rubber. Since such a rubber hose requires a vulcanization process, There is a problem that the manufacturing process becomes complicated. On the other hand, there is also known a so-called resin hose in which the inner tube and the outer tube are made of a thermoplastic resin and whose manufacturing process is simple because a vulcanizing process is not required. However, the thermoplastic resin constituting this resin hose is generally harder than vulcanized rubber, and it has been difficult to obtain a flexible hose.

Further, in order to improve the flexibility of the thermoplastic resin, a resin hose having an inner tube made of a polyester thermoplastic elastomer having polybutylene terephthalate as a hard segment and polytetramethylene glycol or polycaprolactone as a soft segment. It is also known that this polyester-based thermoplastic elastomer has a limit in lowering hardness in order to obtain necessary heat resistance and strength characteristics, and a hose having sufficient flexibility like vulcanized rubber is required. I haven't got it.

Therefore, the development of a hose that can be manufactured by a simple process that does not require a vulcanization process and that has sufficient flexibility and heat resistance that can be used for pressure transmission at high temperature, fluid transportation, etc. has been developed. Was wanted. To meet such demand, a hose having an inner pipe and an outer pipe made of a thermoplastic elastomer in which a vulcanized rubber is dispersed in a thermoplastic resin has been proposed (see Japanese Patent Application No. 6-64102). . This hose comprises an inner tube made of a thermoplastic elastomer in which a vulcanized composition of an acrylic group-containing rubber is dispersed in a polyester-based thermoplastic resin, and is a thermoplastic elastomer in which a vulcanized rubber is dispersed in a thermoplastic resin. Make up the tube. Further, the reinforcing layer is formed by adhering organic fibers such as rayon fibers and polyester fibers to the inner tube and the outer tube through a room temperature curing type urethane adhesive.

[0005]

Although a hose that is flexible and does not require a vulcanization process can be obtained by the above-described structure, the cold-curing urethane adhesive is simply used to form the fiber and the flexible inner tube. And when the outer tube is adhered,
In particular, it has been found that durability is problematic when repetitive impact pressure is applied in a high temperature atmosphere. This is because when the room temperature curing type urethane adhesive is exposed to a high temperature atmosphere after being cured, the hardness is remarkably increased, and when it is deformed, brittle fracture easily occurs particularly in the adhesive layer between the inner tube of the hose and the fiber reinforced layer. It was clarified that it was because of it.

In the case of the conventional resin hose, the inner tube and the outer tube are made of resin and have a high hardness, and the deformation of the inner tube made of the hard resin is suppressed even when the impact pressure is periodically applied. Therefore, it is considered that the adhesive is not broken even if the hardness of the adhesive layer is high.

Therefore, in order to use the above-mentioned flexible thermoplastic elastomer, it is necessary to provide an adhesive layer which has good adhesion to the thermoplastic elastomer and the fiber reinforcing layer, and which is flexible and does not increase in hardness due to heat. . Therefore, an object of the present invention is to eliminate the above-mentioned problems of the prior art and to provide a high pressure hose which is flexible and has excellent durability.

[0008]

That is, according to the present invention, at least an inner tube, a reinforcing fiber layer, and an outer tube are formed, and the inner tube is vulcanized with an acrylic group-containing rubber in a polyester thermoplastic resin. The composition is composed of a dispersed thermoplastic elastomer, and a reinforcing fiber layer on which an organic fiber is adhered via a dealcohol-type or deoxime-type condensation-type room temperature curing silicone rubber adhesive is arranged on the outside thereof, and further thereon. There is provided a hose in which an outer tube made of a thermoplastic elastomer in which a vulcanized rubber is dispersed in a thermoplastic resin is arranged.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic elastomer constituting the inner tube and the outer tube of the hose of the present invention is a thermoplastic resin in an amount sufficient to impart thermoplasticity and an amount sufficient to impart rubber-like elasticity. At least a part is composed of a blend with a vulcanized rubber, and the thermoplastic resin component forms at least a continuous phase (matrix phase) in which at least the rubber component exists as a discontinuous phase (dispersed phase). . A so-called salami structure in which a thermoplastic resin is further dispersed in the discontinuous phase (rubber phase) may be used.

In particular, for the inner tube of the hose according to the present invention, a thermoplastic elastomer comprising a blend of a polyester type thermoplastic resin and a vulcanizing composition of an acrylic group-containing rubber is used, and the desired heat resistance and oil resistance, Further, it is indispensable because it needs to have flexibility. Examples of the polyester-based thermoplastic resin used in this thermoplastic elastomer include polyethylene terephthalate resin, polybutylene terephthalate resin, and the like, and thermoplastic resins and thermoplastic elastomers of block and / or graft copolymers containing these resins as constituent elements. Is exemplified. In particular, it is preferable to use a polyester-based thermoplastic elastomer (for example, Hytrel manufactured by DuPont or Perprene manufactured by Toyobo Co., Ltd.) in that good flexibility can be obtained. On the other hand, examples of the acrylic group-containing rubber used for the inner tube of the hose according to the present invention include acrylic rubber, ethylene / acrylic ester copolymer rubber, ethylene / vinyl acetate / acrylic ester terpolymer rubber, and the like. To be done. The acrylic group-containing rubber includes a rubber in which a main chain and / or a side chain is copolymerized with a monomer such as a vulcanizable acrylic compound and glycidyl ether.

On the other hand, the thermoplastic resin constituting the thermoplastic elastomer used for the outer tube of the hose may be a generally used thermoplastic resin, such as polyethylene resin, polypropylene resin or other polyolefin resin, polyvinyl chloride resin, Examples thereof include polyamide resins and polyester resins. The vulcanized rubber may be a commonly used rubber, such as natural rubber, isoprene rubber, butadiene rubber, styrene / butadiene copolymer rubber, butyl rubber, chloroprene rubber, ethylene / propylene (.diene monomer) copolymer. Rubber, acrylonitrile-butadiene copolymer rubber, chlorinated polyethylene rubber, chlorosulfonated polyethylene rubber, acrylic rubber,
Examples thereof include epichlorohydrin rubber, ethylene / acrylic acid ester copolymer rubber, ethylene / vinyl acetate / acrylic acid ester terpolymer rubber, hydrogenated acrylonitrile / butadiene copolymer rubber, and the like. These thermoplastic resins and rubbers may be used alone or as a mixture of two or more kinds.

The constituent components of the thermoplastic elastomer used in the present invention are the above-mentioned thermoplastic resin and the above-mentioned rubber, and in such a thermoplastic elastomer, at least a part of the rubber component constituting the thermoplastic elastomer is vulcanized. is there. For such a thermoplastic elastomer, a Banbury mixer, a Brabender mixer or a kneading extruder of some kind (a twin-screw kneading extruder) is usually used to maintain the melt of the thermoplastic resin and the rubber in these devices. Then, while the rubber phase is finely kneaded and dispersed, a vulcanizing agent is further added, and mastication is performed at a temperature that accelerates vulcanization until the vulcanization of the rubber phase is completed.

In order to manufacture the hose according to the present invention, a thermoplastic elastomer in which a vulcanized product of an acrylic group-containing rubber is dispersed in the polyester thermoplastic resin constituting the above-mentioned contents is formed by a known extrusion molding method according to the present invention. After manufacturing the inner tube of the hose, apply the adhesive on the outer surface, wrap the reinforcing fiber around it in a blade or spiral shape, apply the adhesive, and again coat the outer tube by thermoplastic elastomer extrusion molding To do.

In the hose according to the present invention, a dealcohol-type or deoxime-type condensation type room temperature curing silicone rubber adhesive is used as an adhesive layer for at least the inner tube and the fiber reinforcing layer. Here, the condensation type room temperature curing silicone rubber adhesive is an organopolysiloxane (mainly dimethylpolysiloxane).
Is a main skeleton, and a hydrolyzable functional group is added to the terminal, and a silane coupling agent for adding adhesiveness is further mixed. When the functional group is an acetoxy group, it is cured by a deacetic acid reaction due to moisture. This is called a deacetic acid type. Further, those having an alkoxy group such as a methoxy group at the end are cured by a dealcohol reaction due to moisture. This is called dealcoholized type. Further, as a functional group, there is a deoxime type in which a methyl ethyl ketoxime is added, and a deacetone type. Among these, according to the present invention, it is important to use a dealcohol type or a deoxime type from the viewpoint of adhesion to fibers and adhesion to a thermoplastic elastomer. A commercially available primer containing a silane coupling agent may be applied to the inner tube and the fiber in advance in order to further improve the adhesiveness.

Next, as the reinforcing layer of the hose according to the present invention, it is possible to use organic fibers such as nylon fiber, vinylon fiber, rayon fiber, polyester fiber and aramid fiber, but in view of economical efficiency, strength and modulus. Therefore, polyester fiber is more preferably used. At least the adhesive between the inner tube and the fiber reinforcement layer must be a dealcohol type or deoxime type as the condensation type room temperature curing silicone rubber adhesive as described above. This is because if the adhesion between the inner tube and the fiber reinforced layer is extremely low in impact pressure durability, a microscopic peeling phenomenon will occur between the inner tube and the fiber reinforced layer when caulking with metal fittings, and oil leakage or escape will easily occur. Is likely to occur. Also, when the internal pressure is applied intermittently, stress concentration is more likely to occur on the side in contact with the inner pipe, so it is important to disperse the stress via a highly flexible adhesive layer in order to prolong the durable life. It is because

Further, the thickness of the adhesive layer between the inner pipe of the hose according to the present invention and the fiber reinforcing layer is preferably 50 to 400 μm. Moisture curable silicone rubber adhesive
Since the adhesive layer is excellent in flexibility and heat resistance but has relatively low mechanical properties, when the adhesive layer is thin, cohesive failure of the adhesive layer is likely to occur when a dynamic durability test such as an impact pressure test is performed. On the other hand, if the thickness of the adhesive layer is too thick, the silicone rubber has a large compression set, and if the end of the hose is crimped with a metal fitting, permanent deformation gradually occurs at the caulking part. Will become loose, and problems such as oil leakage will easily occur during use. By optimizing the thickness, the fracture energy of the adhesive layer can be increased and the amount of permanent compression deformation can be reduced, thereby improving the durability of the hose.

In the high-pressure flexible hose according to the present invention, an outer tube made of a thermoplastic elastomer is arranged on the outside of the fiber reinforced layer with a suitable adhesive. As the adhesive used here, the above-mentioned dealcohol type or deoxime type condensation type room temperature curing silicone rubber adhesive can be used, and also a urethane type adhesive which has been generally used for a hose has been used. You can also The thickness of the second adhesive layer is not particularly limited, but is preferably 10-5.
00 μm.

According to the present invention, the outer tube made of the above-mentioned thermoplastic elastomer is arranged outside the second adhesive layer.

As described above, the high-pressure flexible hose according to the present invention comprises at least the inner tube, the reinforcing fiber layer and the outer tube, but if necessary, an adhesive layer may be further included between the reinforcing layer fiber layers.

[0020]

EXAMPLES The present invention will be further described with reference to the following examples, but it goes without saying that the scope of the present invention is not limited to these examples.

Examples 1 and 2 and Comparative Examples 1 to 3 ACM (acrylic rubber: manufactured by Zeon Corporation) / COPE (Hytrel: manufactured by DuPont) is used as an inner tube, and an adhesive layer is provided on the outer side of the inner tube. A polyester fiber (1500d / 2) was braided, and then a hose having an inner diameter of 9.5 mm and an outer diameter of 17.4 mm was produced in which an ACM / COPE thermoplastic elastomer was arranged as an outer tube via an adhesive layer. The following adhesive was used as the adhesive layer. The average thickness of the adhesive layer was 200 μm. Since the room-temperature-curable urethane adhesive used for comparison has a large fluidity, the amount of adhesive applied was controlled by the weight of the adhesive so that the calculated thickness was 200 μm.

After these hoses were manufactured and allowed to stand for 1 week, the adhesive adhesion between the inner tube and the reinforcing layer was measured, and the adhesive strength measurement results are shown in Table I. Furthermore, the rate of change in the flexibility of this hose before and after heat aging was determined. The flexibility is a simple cantilever system, that is, a hose with a length of 30 cm is 10 from the end.
The load required for bending by 5 cm was determined by fixing the sample at a fixed length of cm and applying the load to the other end, and the rate of change of the load after heat aging from the load before heat aging at 100 ° C. for 48 hours was calculated.

Further, a hose heat-aged at 100 ° C. for 48 hours was subjected to an impact pressure test in accordance with JIS K6375 7.7. As the test oil, a mineral oil corresponding to two kinds specified in JIS K2213 (turbine oil) was used, and a rectangular wave with a maximum pressure of 280 kgf / cm ^{2 was} applied at an oil temperature of 93 ° C.
For those that were not repeatedly destroyed after repeated additions 10,000 times, the condition of oil leakage and the external and internal conditions of the hose were observed.

[0024]

[Table 1]

As shown in Table I, the moisture-curable urethane adhesive of Comparative Example 1 gives high initial adhesion, but the hardness of the adhesive layer increases remarkably in a high temperature atmosphere, and shocking pressure changes are repeatedly given. As a result, stress was concentrated on the rigid adhesive layer, causing brittle fracture of the adhesive layer, and the hose was destroyed.
On the other hand, in the case of using the room temperature-curable silicone rubber adhesive, no deterioration in flexibility due to heat aging is observed. However, the hoses using the deacetic acid type and deacetone type, which have low adhesion, had metal fittings removed due to repeated repeated impact pressure. On the other hand, the dealcohol type and deoxime type room temperature curing type silicone rubbers have slightly lower adhesive strength than the urethane-based adhesive of Comparative Example 1, but they do not cure in a high temperature atmosphere and are clearly impact pressure durable. After the test, no abnormalities were observed and good durability was exhibited.

Example 3 With a hose having the same structure as in Example 1, using deoxime type KE45 as an adhesive and changing the thickness of the adhesive layer, a peeling adhesion test similar to that in Example 1 and a 100 ° C. for 48 hours. The impact pressure durability test was repeated 200,000 times for the heat aged hose. The results are shown in Table II.

[0027]

[Table 2]

As shown in Table II, the adhesive layer thickness is 50 μm.
When it is less than 1, the fracture energy of the adhesive layer becomes small as in Sample 1, the adhesive fracture partially occurs between the inner pipe and the fiber layer, and a slight crack occurs in the inner pipe. Further, it can be seen that when it exceeds 400 μm (Sample 4), oil leakage is more likely to occur from the metal fitting caulking portion due to the influence of compression set. All the results are better than those of Comparative Example 1, but the thickness of the adhesive layer is 50 μm to 400 μm.
It can be seen that the range of μm can provide a hose having higher resistance to repeated impact pressure.

[0029]

As described above, according to the present invention,
An inner tube is composed of a thermoplastic elastomer in which a vulcanized composition of an acrylic-containing rubber is dispersed in a polyester-based thermoplastic resin, and a dealcohol type or deoxime type room temperature curing type silicone rubber adhesive is further used as an adhesive for the fiber reinforcing layer. By using the agent, it is possible to obtain a high-pressure flexible hose having excellent durability without significant curing of the adhesive layer due to heat aging.

Claims (2)

[Claims] 1. A thermoplastic elastomer having at least an inner tube, a reinforcing fiber layer and an outer tube, wherein the inner tube is made of a thermoplastic elastomer in which a vulcanized composition of an acrylic group-containing rubber is dispersed in a polyester thermoplastic resin, A reinforcing fiber layer made by adhering organic fibers through a dealcohol-type or deoxime-type condensation room-temperature-curing silicone rubber adhesive was placed on the outside, and vulcanized rubber was dispersed in the thermoplastic resin on it. A high-pressure flexible hose having an outer tube made of thermoplastic elastomer. 2. The adhesive layer has a thickness of 50 to 400 μm.
The hose according to claim 1, which is