JP2006307988A - Hose - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hose of the spiral braided structure to show the fine durability even if an intermediate rubber layer is eliminated. <P>SOLUTION: The hose comprises at least an inner rubber layer, a reinforcement layer of the spiral braided structure of more than two layers and an outer rubber layer laminated in this order from the inner circumference side, and the reinforcement layer is made of a reinforcement thread satisfying the following formulae (1) and (2). The formula (1) is that the intermediate elongation at 1.2 cN/dtex and 135°C or lower is ≤5.0% and 0.4%≤ and the formula (2) is that the dry heat shrinkage rate after processing for 30 minutes and 150°C or lower is ≤6.0% and ≥1.5%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hose, and more particularly to a spiral hose having a reinforcing layer.

2. Description of the Related Art In a piping hose for a vehicle such as an automobile, a hose having a reinforcing layer formed by using a plurality of reinforcing yarns is used at a place where pressure resistance and durability are required.
This reinforcing layer is braided by wrapping fiber or metal yarn in a braided or spiral shape, but from the viewpoint of cost reduction, a braided structure wound in a spiral shape (hereinafter referred to as “spiral braiding”). "Structure") is often adopted.
Further, in the case of this spiral braid structure, usually, a first reinforcing layer in which reinforcing yarn is wound in a spiral shape, and a second reinforcing layer in which a plurality of reinforcing yarns are wound in a spiral shape in a direction opposite to the first reinforcing layer. In high-pressure hoses, etc., it is known that an intermediate rubber layer is interposed between the reinforcing layers in order to enhance the bondability of the two reinforcing layers and prevent mutual friction to increase durability. (For example, refer to Patent Documents 1 to 3.)

  On the other hand, from the viewpoint of further reducing the cost of high-pressure hoses and the like, it has been studied to eliminate the intermediate rubber layer, but if the intermediate rubber layer is excluded, the bondability between the reinforcing layers decreases, and mutual There was also a problem that the friction could not be suppressed, resulting in a decrease in durability.

On the other hand, from the viewpoint of preventing shelves from dropping, Patent Document 4 states that “inner surface resin tube, inner rubber layer provided on the outer peripheral surface thereof, and a plurality of reinforcing yarns are aligned on the outer peripheral surface to form a spiral shape. A wound first reinforcing layer, a second reinforcing layer in which a plurality of reinforcing yarns are arranged on the outer periphery thereof in a spiral shape in the opposite direction to the first reinforcing layer, and an outer rubber layer provided on the outer periphery A refrigerant high-pressure hose characterized in that the inner rubber layer is made of a rubber material having a 50% modulus M _{50 at a} temperature of 135 ° C. of 20 to 40 kgf / cm ² has been proposed.

Japanese Patent Laid-Open No. 7-68659 JP-A-7-144379 JP 11-325331 A Japanese Patent No. 3396975

However, the present inventor examined the refrigerant high-pressure hose described in Patent Document 4 and found that the durability was insufficient because there was no intermediate rubber layer.
Then, this invention makes it a subject to provide the hose of the spiral braid structure which shows favorable durability, even if an intermediate | middle rubber layer is excluded.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that a hose having a reinforcing layer formed of a reinforcing yarn exhibiting a predetermined intermediate elongation and dry heat shrinkage rate is durable even if the intermediate rubber layer is excluded. Was found to be a good hose, and the present invention was completed.

That is, the present invention provides the following (i).
(I) A hose comprising at least an inner rubber layer, two or more layers of a spiral braided reinforcing layer and an outer rubber layer in this order from the inner circumferential side,
A hose in which the reinforcing layer is formed of a reinforcing yarn that satisfies the relationship represented by the following formulas (1) and (2).
0.4% ≦ 135 ° C., intermediate elongation at 1.2 cN / dtex ≦ 5.0% (1)
1.5% ≦ 150 ° C., dry heat shrinkage after treatment for 30 minutes ≦ 6.0% (2)

  As will be described below, according to the present invention, even when the intermediate rubber layer is eliminated, good durability is obtained. Specifically, pressures of 0 MPa and 5.3 MPa are repeated at 135 ° C. with a cycle of 0.5 Hz. It is possible to provide a hose with a spiral braid structure that exhibits durability that can be operated more than 400,000 times in a test to be added (hereinafter also referred to as “repetitive pressurization test”). It is very useful because it can be realized.

The present invention is described in detail below.
As described above, the hose of the present invention is a hose comprising at least an inner rubber layer, a reinforcing layer having an spiral rubber braid structure of two or more layers, and an outer rubber layer in this order from the inner circumferential side,
The reinforcing layer is a hose formed of a reinforcing yarn that satisfies a relationship represented by the following formulas (1) and (2).
0.4% ≦ 135 ° C., intermediate elongation at 1.2 cN / dtex ≦ 5.0% (1)
1.5% ≦ 150 ° C., dry heat shrinkage after treatment for 30 minutes ≦ 6.0% (2)

  Here, an example of a preferred embodiment of the hose of the present invention will be described with reference to FIG. FIG. 1 is a perspective view showing the hose of the present invention with a part cut away for each layer. As shown in FIG. 1, the hose 1 has a reinforcing layer wound with two reinforcing layers formed by spirally winding a plurality of reinforcing yarns made of a fiber material between an inner rubber layer 2 and an outer rubber layer 5. An inner reinforcing layer 3 positioned on the inner peripheral side of the hose 1 and an outer reinforcing layer 4 positioned on the outer peripheral side, which are embedded in different directions, are provided.

  Next, the inner rubber layer, the spiral braided reinforcing layer (inner reinforcing layer, outer reinforcing layer), and outer rubber layer constituting the hose of the present invention will be described in detail.

<Inner rubber layer>
As the inner rubber layer constituting the hose of the present invention, a conventionally known inner rubber layer used for the hose can be used, and it may be formed of one layer alone or a plurality of layers.

The rubber material for forming such an inner rubber layer is not particularly limited, and specific examples thereof include butyl rubber (IIR), chlorinated butyl rubber (Cl-IIR), brominated butyl rubber (Br-IIR), and acrylonitrile-butadiene rubber. (NBR), hydrogenated acrylonitrile-butadiene rubber (HNBR) and the like may be used, or one kind may be used alone, or two or more kinds may be mixed and used.
Among these, it is preferable to use butyl rubber (IIR), chlorinated butyl rubber (Cl-IIR), or brominated butyl rubber (Br-IIR) because of excellent heat resistance, gas permeability resistance, and moisture permeability resistance.

In the present invention, the inner rubber layer may be formed of rubber alone, but contains various additives depending on the use of the hose of the present invention, the physical properties required for the hose of the present invention, and the like. The rubber composition may be formed.
Specific examples of additives that may be contained as needed include vulcanizing agents, vulcanization accelerators, fillers, reinforcing agents, plasticizers, anti-aging agents, softeners, tackifiers, Examples include lubricants, dispersants, processing aids, and the like.

  In the present invention, the thickness of the inner rubber layer is not particularly limited because it can be set to any thickness depending on the use of the hose of the present invention and the physical properties required for the hose of the present invention. However, it is about 0.5-4.0 mm.

<Reinforcing layer>
The reinforcement layer which comprises the hose of this invention is formed with the reinforcement thread | yarn which satisfy | fills the relationship shown to following formula (1) and (2).
0.4% ≦ 135 ° C., intermediate elongation at 1.2 cN / dtex ≦ 5.0% (1)
1.5% ≦ 150 ° C., dry heat shrinkage after treatment for 30 minutes ≦ 6.0% (2)

  Here, “at 1.2 cN / dtex” in the above formula (1) is assumed to be a pressure applied per reinforcing yarn forming a reinforcing layer when a pressure of about 5.3 MPa is applied to the hose. It is a thing. In the present invention, when the reinforcing yarn forming the reinforcing layer satisfies the relationship expressed by the above formula (1), the change in the outer shape of the hose when a pressure of about 5.3 MPa is applied to the hose is limited to an appropriate range. The deterioration of the performance due to repeated fatigue associated with the continuous use of the hose is prevented, and the durability is improved.

  In the above formula (2), “after treatment at 150 ° C. for 30 minutes” assumes heat treatment during vulcanization. When the reinforcing yarn shrinks due to dry heat shrinkage during the heat treatment during vulcanization, the reinforcing yarn bites into the inner rubber layer, and the rubber blows out from these rubber layers, so that two or more reinforcing layers are Will adhere. In the present invention, when the reinforcing yarn forming the reinforcing layer satisfies the relationship expressed by the above formula (2), the amount of biting into the rubber layer by the reinforcing yarn becomes appropriate, and even if there is no intermediate rubber layer, The rubber blown out suppresses the rubbing of the reinforcing yarn and also improves the adhesion between the reinforcing layers.

  The reinforcing yarn forming the reinforcing layer constituting the hose of the present invention is not particularly limited as long as it is made of a fiber material. Specifically, polyester fibers (for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN) Etc.), nylon fibers, rayon fibers, aromatic polyamide fibers, polyketone fibers and the like. Of these, polyethylene terephthalate (PET) fibers are preferably used from the viewpoint of cost.

Such a twisted structure of the reinforcing yarn is not particularly limited, and may be either twisted or untwisted.
In addition, the processing conditions for making such a reinforcing yarn a reinforcing yarn satisfying the relationship expressed by the above formulas (1) and (2) are not particularly limited because they vary depending on the type of the reinforcing yarn.
Further, such a reinforcing yarn is preferably subjected to a treatment of immersing in an adhesive from the viewpoint of adhesion to the inner rubber layer and the outer rubber layer. The adhesive is not particularly limited, but a mixed solution (RFL) of a resorcin / formalin precondensate aqueous solution and a rubber latex is preferably used from the viewpoints of cost, adhesiveness to various rubbers, and the like.

The reinforcing layer constituting the hose of the present invention is formed by spirally winding a reinforcing yarn satisfying the relationship shown in the above formulas (1) and (2) on the inner rubber layer.
Moreover, in the hose of this invention, the thickness of the said reinforcement layer can be made into arbitrary thickness according to the use etc. with which the hose of this invention is used, the physical property requested | required of the hose of this invention, etc.

<Outer rubber layer>
As the outer rubber layer constituting the hose of the present invention, a conventionally known outer rubber layer used for a hose can be used, and it may be formed of one layer alone or a plurality of layers.

The rubber material for forming such an outer rubber layer is not particularly limited, and specific examples thereof include styrene-butadiene rubber (SBR), chloroprene rubber (CR), butyl rubber (IIR), and chlorinated butyl rubber (Cl-IIR). , Brominated butyl rubber (Br-IIR), ethylene-propylene-diene rubber (EPDM), chlorosulfonated polyethylene rubber (CSM), etc., and may be used alone or in combination of two or more. Good.
Among these, it is preferable to use ethylene-propylene-diene rubber (EPDM) because of excellent weather resistance, heat resistance, and moisture permeability resistance.

In the present invention, the outer rubber layer may be formed of rubber alone, but contains various additives depending on the use of the hose of the present invention, the physical properties required for the hose of the present invention, etc. The rubber composition may be formed.
Examples of the additive that may be contained as necessary include various additives exemplified above as the rubber composition for forming the inner rubber layer.

  Further, in the present invention, the thickness of the outer rubber layer is not particularly limited because it can be set to any thickness depending on the use of the hose of the present invention, the physical properties required for the hose of the present invention, and the like. However, it is about 0.5-3.0 mm.

  The hose of this invention may be equipped with the resin layer shown below as needed other than the inner surface rubber layer, reinforcement layer, and outer surface rubber layer which were mentioned above.

(Resin layer)
The hose of the present invention may include a resin layer inside the inner rubber layer. The resin layer is not particularly limited as long as it is formed of a conventionally known resin, and may be formed of a single layer or a plurality of layers.

Specific examples of the resin material for forming such a resin layer include, for example, polyamide resins, polyethylene resins, polypropylene resins, polyester resins, fluorine resins, vinyl chloride resins, polyether resins, and polyresins. A methacrylate resin, a polyvinyl resin, etc. are mentioned, It may be used individually by 1 type, or 2 or more types may be mixed and used for it.
Among these, the optimum resin material differs depending on the application. For example, in the case of an automotive air conditioner hose, it is preferable to use a polyamide-based resin for the reason that the refrigerant permeability is particularly excellent. Specifically, nylon 6 (N6 It is more preferable to use a mixed resin (blend) of nylon 11 (N11).

  As described above, such a hose of the present invention is very useful because it is excellent in durability even without an intermediate rubber layer and can be reduced in cost by eliminating the intermediate rubber layer. Therefore, the hose of the present invention can be applied not only to an automobile air conditioner hose and a power steering hose, but also to a high pressure hose in which an intermediate rubber layer is conventionally interposed between reinforcing layers.

  The method for producing the hose of the present invention is not particularly limited, and a conventionally known method can be used as a method for producing the hose. Specifically, the inner rubber layer, the inner reinforcing layer, and the outer reinforcement are formed on a mandrel. After laminating the layers and the outer rubber layer in this order, the layers are subjected to press vulcanization, steam vulcanization, oven vulcanization (hot air vulcanization) or hot water vulcanization at 140 to 190 ° C. for 30 to 180 minutes. A method of producing by vulcanization adhesion by vulcanization is preferably exemplified.

  Hereinafter, the hose of the present invention will be described in more detail using examples. However, the present invention is not limited to these examples.

(Production of reinforcing yarn)
The cord structures of the following reinforcing yarns 1 to 8 were all 1100 dtex // 3 single twist structure (twist number: 10 times / 10 cm, S twist).

(Reinforcing thread 1)
A cord made of polyethylene terephthalate was dipped in a bath with an RFL adhesive solid content concentration of 10%, and then a reinforcing yarn heat-treated at 235 ° C. for 60 seconds under a −4% stretch was used.

(Reinforcing thread 2)
A cord made of polyethylene terephthalate was dipped in a bath having an RFL adhesive solid content concentration of 10%, and then a reinforcing yarn heat-treated at 235 ° C. for 60 seconds under a stretch of + 3% was used.

(Reinforcing thread 3)
A cord made of polyethylene terephthalate was dipped in a bath having an RFL adhesive solid content concentration of 10%, and then a reinforcing yarn heat-treated at 235 ° C. for 60 seconds under a ± 0% stretch was used.

(Reinforcing thread 4)
A cord made of polyethylene terephthalate was dipped in a bath having an RFL adhesive solid content concentration of 10%, and then a reinforcing yarn heat-treated at 235 ° C. for 60 seconds under a −1% stretch was used.

(Reinforcing thread 5)
A cord made of polyethylene naphthalate was dipped in a bath having an RFL adhesive solid content concentration of 10%, and then a reinforcing yarn heat-treated at 240 ° C. for 60 seconds under a stretch of ± 0% was used.

(Reinforcing thread 6)
A cord made of polyethylene terephthalate was dipped in a bath having an RFL adhesive solid content concentration of 10%, and then a reinforcing yarn heat-treated at 235 ° C. for 60 seconds under a stretch of + 5% was used.

(Reinforcing thread 7)
A cord made of polyethylene naphthalate was dipped in a bath having an RFL-based adhesive solid content concentration of 10%, and then a reinforcing yarn heat-treated at 240 ° C. for 60 seconds under a −1% stretch was used.

(Reinforcing thread 8)
After a cord made of aramid was dipped in a bath having an RFL adhesive solid content concentration of 10%, a reinforcing yarn heat-treated at 240 ° C. for 60 seconds under a ± 0% stretch was used.

  The intermediate elongation and dry heat shrinkage rate of each of the produced reinforcing yarns 1 to 8 were measured under the following conditions. The results are shown in Table 1 below.

<Intermediate elongation>
For each of the reinforcing yarns 1 to 8, the intermediate elongation at 135 ° C. and 1.2 cN / dtex was measured according to JIS L1017: 02.

<Dry heat shrinkage>
About each reinforcement thread | yarn 1-8, the dry heat shrinkage rate after a 30-minute process was measured according to JISL1017: 02 under 150 degreeC.

(Examples 1-4, Comparative Examples 1-4)
A hose using a reinforcing layer made of each of the obtained reinforcing yarns 1 to 8 was produced as shown below.
First, an inner rubber layer made of an IIR rubber composition was extruded on a mandrel having an outer diameter of 14 mm so as to have a thickness of 2.0 mm, thereby forming an inner tube.
Next, each reinforcing thread 1-8 obtained on the inner pipe is spirally wound in one direction to form an inner reinforcing layer, and the same reinforcing thread is wound on the inner pipe in a spiral direction in the opposite direction to the inner reinforcing layer. An outer reinforcing layer was formed.
Thereafter, an outer rubber layer made of an EPDM rubber composition was extruded on the outer reinforcing layer so as to have a thickness of 1.5 mm, thereby forming an outer tube.
Next, ribbon wrapping was performed, and heat vulcanization was performed at about 154 ° C. for 60 minutes using a vulcanizing can, and then unwrapping and mandrel removal were performed to obtain a hose.

  About each obtained hose, the mandrel pulling-out property, the repeated pressurization test, the interlayer adhesiveness, the thread rubbing, and the residual strength were evaluated by the methods shown below. The results are shown in Table 2 below.

<Mandrel detachability>
The mandrel detachability is evaluated by confirming the mandrel detachability when a pressure of 5 MPa is applied to the end of the unwrapped mandrel hose obtained immediately after vulcanization, and less than 5 seconds after pressurization. The hose where the mandrel began to fall out was evaluated as ○ with an excellent mandrel slipping ability, and it took 5 seconds or more after pressurization until the mandrel began to pull out, or the hose that did not slip out was rated as poor with a mandrel slipping ability. did.

<Repetitive pressure test>
Each obtained hose was subjected to a repeated pressurization test in which pressures of 0 MPa and 5.3 MPa were repeatedly applied at a cycle of 0.5 Hz at 135 ° C. to evaluate pressure resistance. In a repeated pressurization test, a hose that operated 400,000 times or more was evaluated as “good” as being excellent in durability, and a hose that operated less than 400,000 times was evaluated as “inferior in durability” as “poor”.

<Interlayer adhesion>
Interlaminar adhesion was evaluated according to JIS K6330-6: 98, and the peel strength between the inner reinforcing layer and the outer reinforcing layer at 135 ° C. was measured.

<Thread rubbing>
For evaluation of yarn rubbing, the rubbing of the reinforcing yarn of each hose after the repeated pressure test was visually confirmed.

<Residual strength>
The reinforcing yarn before and after the repeated pressure test is taken out of the hose, the strength is measured according to JIS L1017: 02, the strength retention rate (index) before and after the test is examined, and the one showing 90 or more is judged to be excellent in the residual strength. did.

  From the results shown in Table 2, the hoses of Examples 1 to 4 using the reinforcing yarns 2 to 5 were compared with Comparative Examples 1 to 4 in repeated pressure tests (pressure resistance), interlayer adhesion, yarn rubbing, and remaining. It was found that strength and mandrel detachability were all good. Furthermore, in the hoses of Examples 1 to 3, it was found that even if inexpensive PET is used as the material of the reinforcing yarn, the physical properties are excellent, and thus the manufacturing cost is advantageous.

FIG. 1 is a perspective view showing the hose of the present invention with a part cut away for each layer.

Explanation of symbols

1 Hose 2 Inner Rubber Layer 3 Inner Reinforcement Layer 4 Outer Reinforcement Layer 5 Outer Rubber Layer

Claims (1)

At least a hose comprising an inner rubber layer, two or more layers of a spiral braided reinforcing layer and an outer rubber layer in this order from the inner circumference side,
A hose in which the reinforcing layer is formed of a reinforcing yarn that satisfies the relationship represented by the following formulas (1) and (2).
0.4% ≦ 135 ° C., intermediate elongation at 1.2 cN / dtex ≦ 5.0% (1)
1.5% ≦ 150 ° C., dry heat shrinkage after treatment for 30 minutes ≦ 6.0% (2)

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