JPH1130362A - Hose for refrigerant transportation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hose for refrigerant transportation of high durability and high pressure-proof without producing a void cavity caused by hygroscopic moisture of yarn even in atmospheric curing required to maintain continuous production of the hose. SOLUTION: It is a hose for refrigerant transportation provided by atmospheric curing after providing a reinforcing yarn layer 3 on an outer peripheral surface of a low moisture permeable internal layer rubber layer 2 and providing a low moisture permeable jacket rubber layer 5 on an outer peripheral surface of the reinforcing yarn layer 3. Reinforcing yarn of the reinforcing yarn layer 3 contains 20 weight % of total aromatic polyester yarn, a total denier is 2000-5500 deniers and equilibrium moisture content regain at 35 deg.C and under relative humidity 85% is less than 1.2 weight %.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant transport hose suitable as a hose for piping of a car cooler or an air conditioner of an automobile, and more particularly to a refrigerant transport hose having excellent continuous productivity, high durability and high pressure resistance. For hose.

[0002]

2. Description of the Related Art A conventional hose for transporting a refrigerant such as Freon R-134a is generally provided between an inner rubber layer and an outer rubber layer.
It has a structure in which a reinforcing yarn layer in which a reinforcing yarn is wound in a spiral shape or a blade shape is provided.The inner rubber layer and the outer rubber layer ensure the refrigerant permeation resistance and the heat resistance, as well as the moisture in the hose. Butyl or E
It is made of PDM rubber.

[0003] Such a hose for transporting refrigerant is usually manufactured by winding a reinforcing yarn in a spiral or blade shape around the outer peripheral surface of an inner rubber layer, arranging an outer rubber layer thereon and vulcanizing it. ing.

[0004] In particular, a reinforcing yarn layer having a spiral structure forms a first reinforcing yarn layer by spirally winding a reinforcing yarn around the outer peripheral surface of an inner rubber layer, and forms a first reinforcing yarn layer thereon in a direction opposite to the first reinforcing yarn layer. It has a two-layer structure in which a reinforcing yarn is spirally wound to form a second reinforcing yarn layer, and if necessary, an inner rubber layer and an outer rubber layer are provided between the first reinforcing yarn layer and the second reinforcing yarn layer. An intermediate rubber layer capable of being vulcanized and bonded is provided on the rubber layer.

As the reinforcing yarn, PET, polyamide or the like is generally used, but in order to improve the durability and pressure resistance of the hose, an aramid yarn which is a high-strength reinforcing yarn may be used in some cases.

In the production of such a hose for transporting refrigerant, if a vulcanization method such as steam, lead or hot water, which is employed in a batch line, is employed as a vulcanization method, the vulcanization process will be difficult. It is difficult to produce continuously up to.

Therefore, conventionally, after forming the outer rubber layer, a mold is continuously coated on the outer rubber layer,
Thereafter, a method of continuously vulcanizing in a heating furnace at normal pressure (so-called HAV) is employed.

[0008]

In recent years, it has become necessary to further improve the durability and pressure resistance of a hose for transporting a refrigerant. It is required to achieve high durability and high withstand voltage.

However, in the case of conventional reinforcing yarns such as PET and polyamide, the breaking strength of the yarn is low, so that it is not possible to increase the pressure resistance.

When an aramid-based high-strength reinforcing yarn is used, the durability and pressure resistance can be increased. However, since the aramid-based yarn has a hygroscopic property, the following is required in continuous production of a hose. Causes serious problems. That is, since the reinforcing yarn layer is sandwiched between the inner rubber layer and the outer rubber layer, through which moisture hardly penetrates, the escape of moisture released from the reinforcing yarn during vulcanization due to moisture absorption by the reinforcing yarn and vulcanization. Absent. For this reason, in the normal-pressure vulcanization step for continuous production, the moisture-absorbing moisture foams, and voids are formed around the yarn, resulting in a product defect.

The present invention solves the above-mentioned conventional problems, and does not generate void-like cavities due to moisture absorption of the reinforcing yarns even in normal pressure vulcanization for continuous production of hoses. It is an object of the present invention to provide a refrigerant transport hose having a high pressure resistance.

[0012]

The refrigerant transport hose of the present invention has a reinforcing yarn layer provided on the outer periphery of an inner rubber layer having low moisture permeability, and a jacket having low moisture permeability on the outer periphery of the reinforcing yarn layer. In a refrigerant transport hose obtained by providing a rubber layer and vulcanizing under normal pressure, the reinforcing yarn of the reinforcing yarn layer contains at least 20% by weight of a wholly aromatic polyester yarn, and the total denier of the reinforcing yarn is 2000%.
５5500 denier and 35% of the reinforcing yarn
The equilibrium water content at 85 ° C. and a relative humidity of 85% is not more than 1.2% by weight.

By using a wholly aromatic polyester yarn having a high breaking strength characteristic so as to have the above-mentioned ratio and total denier as the reinforcing yarn, it becomes possible to achieve high durability and high pressure resistance of the hose. Moreover, since the wholly aromatic polyester yarn has almost no moisture absorption, even when blended with other yarns having moisture absorption, if the amount of moisture is controlled within the above range of the equilibrium moisture content, the vulcanization at normal pressure can be performed. In addition, void-like cavities due to moisture absorption of the reinforcing yarn are not generated. Therefore, it is possible to manufacture a highly durable, high pressure resistant hose having excellent continuous productivity by normal pressure vulcanization.

In the present invention, the reinforcing yarn layer has a first reinforcing yarn layer having a spiral structure, and a spiral structure wound on the first reinforcing yarn layer in a direction opposite to the first reinforcing yarn layer. It is preferably formed with the second reinforcing yarn layer. In this case, it is preferable that an intermediate rubber layer is formed between the first reinforcing yarn layer and the second reinforcing yarn layer.

The rubber constituting the inner rubber layer and the outer rubber layer is preferably butyl rubber or EPDM rubber, and it is preferable to further form an inner resin layer on the inner periphery of the inner rubber layer.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of a refrigerant transport hose of the present invention.

In this refrigerant transport hose, the inner rubber layer 2
A reinforcing yarn layer 3 is formed between the outer rubber layer 5 and the inner rubber layer 5, and an inner resin layer 1 is formed on the inner periphery of the inner rubber layer 2. The reinforcing yarn layer 3 includes a first reinforcing yarn layer 3A in which reinforcing yarn is spirally wound, and a second reinforcing yarn layer 3B in which reinforcing yarn is spirally wound in a direction opposite to the first reinforcing yarn layer 3A. It is formed by lamination via the intermediate rubber layer 4.

The rubber constituting the inner rubber layer 2 and the outer rubber layer 5 is not particularly limited as long as it has low moisture permeability, and is generally butyl rubber (IIR) or chlorinated butyl rubber (Cl-IIR). , Chlorinated polyethylene, chlorosulfonated polyethylene, brominated butyl rubber (Br-II
R), isobutylene-bromoparamethylstyrene copolymer, EPR (ethylene-propylene copolymer), EPD
M (ethylene-propylene-diene terpolymer) and a blend thereof with another polymer containing these as a main component, preferably butyl rubber and EPDM rubber are used.
These rubbers usually contain fillers, processing aids,
Formulations such as anti-aging agents, vulcanizing agents and vulcanization accelerators can be applied.

The rubber type of the inner rubber layer 2 and the rubber type of the outer rubber layer 5 may be the same or different.

The thicknesses of the inner rubber layer 2 and the outer rubber layer 5 are as follows:
In general, the thickness of the inner rubber layer 2 is 0.1 to 10.0 mm, and the thickness of the outer rubber layer 5 is 0.1 to 10.0 mm, although it varies depending on the purpose of use and required characteristics. .

The resin of the inner resin layer 1 provided on the inner peripheral surface of the inner rubber layer 2 may be a polyamide resin having excellent refrigerant permeation resistance, a blend or copolymer of polyamide resins, or a polyamide resin. Olefin, butyl rubber, E
Blends with PDM, EPR rubbers, ionomers and the like are used. The thickness of the inner resin layer 1 is usually 0.02 to
It is about 0.4 mm. By providing such an inner resin layer 1, the hose can have improved refrigerant permeation resistance.

The first reinforcing yarn layer 3A and the second reinforcing yarn 3B formed between the inner rubber layer 2 and the outer rubber layer 5 are ply-twisted,
In the present invention, the reinforcing yarn is formed by spirally winding a reinforcing yarn having a twist of about 3 to 20 times / 10 cm in both twisting. In the present invention, as the reinforcing yarn constituting this reinforcing yarn layer, a wholly aromatic polyester yarn is used. % Or more, a total denier of 2000 to 5500 denier, and an equilibrium water content at 35 ° C. and a relative humidity of 85% of 1.2% or less are used.

In the present invention, when the weight ratio of the wholly aromatic polyester yarn in the reinforcing yarn is less than 20% by weight, when the other yarn type is a yarn having a low breaking strength, the pressure resistance or durability of the hose is reduced. Insufficiency and other yarn types are yarns with high breaking strength, all such yarns have high moisture absorption, so voids around the yarn due to foaming of moisture during normal pressure vulcanization. A cavity is created. The preferred weight ratio of the wholly aromatic polyester yarn is 30 to 100% by weight, more preferably 40 to 100% by weight. As the reinforcing yarn other than the wholly aromatic polyester yarn, PET (polyethylene terephthalate), polyamide, aramid (aromatic polyamide), vinylon, rayon, polyethylene naphthalate, or the like can be used.

When the total number of deniers of the reinforcing yarn (the sum of deniers of the aligned yarns) is less than 2000 denier, the pressure resistance or durability of the hose is insufficient, and the hose is 550.
If it is greater than 0 denier, the reinforcing yarn becomes too thick, resulting in a poor appearance of the hose.

Further, even when the weight ratio of the wholly aromatic polyester yarn is 20% or more, the yarn is not heated at 35 ° C. and a relative humidity of 85% as a reinforcing yarn obtained by blending with a nylon yarn having an extremely high moisture absorption property. If the equilibrium water content of the rubber composition exceeds 1.2%, voids are formed around the yarn due to foaming of the water during normal pressure vulcanization. Therefore, the equilibrium water content is set to 1.2% or less, preferably 1.0% or less.

As shown, the reinforcing yarn layer 3 having a spiral structure
When forming A and 3B, the reinforcing yarns of the reinforcing yarn layers 3A and 3B are preferably wound in opposite directions at an angle (an angle with respect to the axis of the hose) of 50 to 60 °. The reinforcing yarn of the first reinforcing yarn layer 3A and the reinforcing yarn of the second reinforcing yarn layer 3B are:
As long as the above conditions are satisfied, they may be the same or different.

The rubber of the intermediate rubber layer 4 between the reinforcing yarns 3A and 3B may be any rubber that can be vulcanized and bonded to both the inner rubber layer 2 and the outer rubber layer 5. The rubber exemplified for the outer rubber layer 5 can be used. The thickness of the intermediate rubber layer 4 is usually 0.1 to 1.0 m.
m. By providing such an intermediate rubber layer 4, the interlayer adhesion between the inner rubber layer 2 and the outer rubber layer 5 can be enhanced.

The refrigerant transport hose shown in FIG. 1 is an example of an embodiment of the present invention, and the present invention is not limited to the illustrated one.

For example, the inner resin layer 1 and the intermediate rubber layer 4 are not necessarily required, and may be omitted.

The reinforcing yarn layer is not limited to the spiral structure, but may be a blade structure. However, a spiral structure is preferable from the viewpoint of productivity.

The method for vulcanizing a hose for transporting refrigerant according to the present invention comprises:
It is not particularly limited as long as it can be vulcanized under normal pressure,
Usually, a method of continuously covering the outer peripheral surface of the outer rubber with a mold and subsequently vulcanizing by the HAV method is adopted.

[0033]

EXAMPLES The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples unless it exceeds the gist.

The rubber compositions of the inner rubber layer, the intermediate rubber layer and the outer rubber layer used in the following Examples and Comparative Examples are as shown in Tables 1 to 3 below.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

Examples 1 to 12 and Comparative Examples 1 to 15 A refrigerant transport hose having the structure shown in FIG. 1 was manufactured by the following procedure.

On a mandrel having a diameter of 11 mm, a thickness of about 0.1 mm is applied.
After coating a 15 mm 6 nylon and olefin blend resin, the inner layer rubber shown in Table 1 was applied to a thickness of 1.5 to 1.6 m.
m. On this, the reinforcing yarns shown in Tables 4 to 6 were spirally wound at an angle of 54 ° 44 ′ to form a first reinforcing yarn layer. The intermediate rubber shown in Table 2 was extruded onto the first reinforcing yarn layer to a thickness of 0.3 mm, and the same reinforcing yarn as the reinforcing yarn of the first reinforcing yarn layer was spirally formed in the opposite direction to the first reinforcing yarn layer. To form a second reinforcing yarn layer. In addition,
The used reinforcing yarn was left at 35 ° C. and a relative humidity of 85% for 72 hours or more before use, assuming environmental conditions in summer.

Next, the outer rubber shown in Table 3 was extruded to a thickness of 1 mm on the second reinforcing yarn layer, and a polyolefin resin was coated thereon as a vulcanizing mold to a thickness of 2 mm.

Thereafter, 45 ° C. at 150 ° C. by the HAV method.
After vulcanization for one minute, the mold was removed to obtain a refrigerant transport hose.

With respect to the obtained refrigerant transport hose, the quality (hollowness, appearance judgment) and abilities (pressure resistance, repeated pressurization judgment) of the hose were examined by the following methods, and the results are shown in Tables 4 to 6.

The dismantling cavity judgment resulting hose, check for voids shaped cavity due to the absorbed moisture of the yarn, × what cavity, nothing was as ○.

The appearance of the hose was observed. The hose having large irregularities was evaluated as x, and the hose having no irregularities and excellent in surface properties was evaluated as ○.

[0045] The pressure resistance of the pressure resistance measurement and determination hose measured in accordance with JIS K6330, and ○ as compatible with the high-voltage applications what is 300 kg / cm ² or more, incompatible ones smaller than 300 kg / cm ² And x.

The repetitive pressurization judgment high-temperature impulse test was carried out at oil temperature and ambient temperature of 140 ° C.
A rectangular wave with an internal pressure of 36 kg / cm ² and a pressurization cycle of 60 CPM was performed (according to the standards of the Japan Refrigeration and Air Conditioning Industry Association), 60
The sample was evaluated as ○ when there was no abnormality after a lapse of 10,000 times, and as X when there was an abnormality such as burst or leakage.

Note that * 1 to * 4 in Tables 4 to 6 are as follows.

* 1 Whole aromatic polyester yarn: "Vectran" manufactured by Kuraray Co., Ltd. * 2 PET: Polyethylene terephthalate yarn manufactured by Teijin KEV: Aramid yarn manufactured by Toray Nylon: 66 nylon yarn manufactured by Toray * 3 * 4 Saturated water content when left for 72 hours at 35 ° C. and 85% relative humidity.
Each of the twists was performed 10 times per 10 cm.

[0049]

[Table 4]

[0050]

[Table 5]

[0051]

[Table 6]

As is clear from Tables 4 to 6, when the reinforcing yarn of the present invention is used, no voids are generated around the yarn in normal pressure vulcanization, no abnormal appearance is observed, and continuous productivity is maintained. As it is, a high pressure-resistant and highly durable hose can be obtained. On the other hand, in the case of the reinforcing yarn which is out of the scope of the present invention,
Either the quality or performance of the hose becomes a problem.

[0053]

As described in detail above, according to the present invention, continuous production by normal pressure vulcanization can efficiently provide a highly durable and high pressure resistant refrigerant transport hose without causing product defects. It can be manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a refrigerant transport hose of the present invention.

[Explanation of symbols]

 Reference Signs List 1 inner resin layer 2 inner rubber layer 3 reinforcing yarn layer 3A first reinforcing yarn layer 3B second reinforcing yarn layer 4 intermediate rubber layer 5 outer rubber layer

Claims (5)

[Claims] 1. A low-moisture permeable inner rubber layer is provided with a reinforcing yarn layer on the outer periphery thereof, and a low-moisture permeable outer rubber layer is provided on the outer periphery of the reinforcing yarn layer, and then vulcanized at normal pressure. The reinforcing yarn of the reinforcing yarn layer contains at least 20% by weight of a wholly aromatic polyester yarn, and the total denier of the reinforcing yarn is from 2000 to 55%.
A hose for transporting a refrigerant, wherein the hose has a denier of 00 and an equilibrium water content of the reinforcing yarn at 35 ° C. and a relative humidity of 85% is 1.2% by weight or less. 2. A reinforcing yarn layer comprising: a first reinforcing yarn layer having a spiral structure; and a spiral in which a reinforcing yarn is wound on the first reinforcing yarn layer in a direction opposite to the first reinforcing yarn layer. The refrigerant transport hose according to claim 1, wherein the hose is formed by a second reinforcing yarn layer having a structure. 3. The hose for cooling and transporting according to claim 2, wherein an intermediate rubber layer is formed between the first reinforcing yarn layer and the second reinforcing yarn layer. 4. The refrigerant transport hose according to claim 1, wherein an inner resin layer is formed on an inner periphery of the inner rubber layer. 5. The refrigerant transport hose according to claim 1, wherein the rubber constituting the inner rubber layer and the outer rubber layer is butyl rubber or EPDM rubber. .