JP2002061778A - Hose for refrigerant transport - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively provide a hose for refrigerant transport that excels in refrigerant permeation resistance and flexibility, requires no application of adhesive to a nipple in a crimping operation and poses no limits to lubricating oil for a compressor, despite of no barrier layers of synthetic resin such as polyamide. SOLUTION: The hose for refrigerant transport comprises a succeeding lamination of, from the inner layer side, at least an inner tube rubber layer, a reinforcing layer and a sheathing rubber layer. The inner tube rubber layer has an at least two-layered laminated structure having different rubber polymers as base materials. The innermost layer has an oil-resistant rubber polymer as the base material, and the other layers have a refrigerant permeation-resistant rubber polymer as the base material.

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 composed of a combination of rubber and a reinforcing layer.
More specifically, the present invention relates to a hose for transporting refrigerant for automobiles, which is excellent in refrigerant permeability, flexibility and oil resistance by improving the structure and material of an inner tube rubber layer, and is also suitable in terms of environment and cost.

[0002]

2. Description of the Related Art Conventionally, a synthetic resin such as polyamide is used for the innermost layer of a composite hose mainly used as a hose for transporting refrigerant for automobiles, and an inner tube rubber layer, a reinforcing layer and an outer rubber layer are provided outside the inner layer. The layers are sequentially stacked. The composite hose having such a configuration has a refrigerant permeation resistance, a moisture permeation resistance,
It has excellent effects such as heat resistance and durability.

[0003]

The refrigerant transporting hose for automobiles having the synthetic resin layer as the innermost layer as described above has a great effect of suppressing the permeation of the refrigerant, but has a great effect. Becomes complicated and increases the cost.
Due to the presence of the hard synthetic resin layer, there was a disadvantage that the flexibility of the hose was impaired.

Further, when a hose having a synthetic resin layer as the innermost layer is assembled with a mounting bracket, since the innermost surface is formed of a hard resin layer, it is difficult to adhere to the nipple, and the refrigerant from the caulked portion becomes difficult. There is also a drawback that leakage easily occurs. In order to compensate for this drawback, it is essential to apply a sealing material such as an adhesive to the nipple surface, which is not preferable in terms of environment and cost.

In order to solve such a problem, a so-called "barrier type hose" is provided in which a rubber layer is used as an innermost layer, and a synthetic resin layer is provided as a barrier layer on the rubber layer. Although it has been devised and put to practical use, it has a hose inferior in flexibility in any way because of the synthetic resin layer.

In order to achieve both flexibility and assembly performance, a so-called "nylon-less hose" in which the innermost synthetic resin layer is omitted and a butyl rubber (IIR) -based rubber polymer is used on the innermost surface has been devised. However, when mineral oil is used as the lubricating oil, there is a problem that the inner tube rubber swells and refrigerant leakage may occur.

Accordingly, an object of the present invention is to provide an adhesive coating to a nipple at the time of crimping which is excellent in refrigerant permeation resistance and excellent in flexibility even though there is no barrier layer made of a synthetic resin such as polyamide. Another object of the present invention is to provide a low-cost hose for transporting a refrigerant that does not require a lubricant for a compressor.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventor did not provide an inner layer made of a synthetic resin, but made the inner tube rubber layer a laminated structure made of a different rubber polymer. The inventors have found that the above object can be achieved by forming the innermost layer with an oil-resistant rubber polymer and the other layers with a refrigerant-permeable rubber polymer, thereby completing the present invention. That is, the present invention is as described below.

<1> A hose for transporting refrigerant comprising at least an inner tube rubber layer, a reinforcing layer, and a jacket rubber layer sequentially laminated from the inner layer side, wherein the inner tube rubber layer comprises a different rubber polymer as a base material. A hose for transporting refrigerant characterized by having a laminated structure of at least two layers, wherein the innermost layer is based on an oil-resistant rubber polymer, and the other layers are based on a refrigerant-permeable rubber polymer. is there.

<2> In the refrigerant transporting hose of <1>, the inner rubber layer is formed of a different rubber polymer as a base material, and a first inner rubber layer and a second inner rubber layer outside the inner rubber layer. Is a hose for transporting refrigerant.

<3> In the refrigerant transport hose according to <2>, the rubber polymer substrate of the first inner tube rubber layer is made of nitrile rubber (NBR) or hydrogenated nitrile rubber (H-NB).
R), chloroprene rubber (CR), acrylic rubber (AC
M) and a refrigerant transporting hose selected from the group consisting of ethylene acrylic copolymer (AEM) rubber polymers.

<4> The refrigerant transport hose according to <2>, wherein the rubber polymer substrate of the second inner tube rubber layer is a butyl rubber (IIR) rubber polymer.

<5> In the refrigerant transport hose according to <2>, the first inner rubber layer has a thickness of 0.2 to 1.5 mm.
Is a refrigerant transport hose.

<6> In the refrigerant transport hose of <2>, the second inner rubber layer has a thickness of 0.5 to 2.5 mm.
Is a refrigerant transport hose.

<7> The refrigerant transport hose according to <2>, wherein the outer surface of the first inner pipe rubber layer is subjected to a surface treatment.

<8> The refrigerant transport hose according to <2>, wherein the second inner tube rubber layer is mixed with a flaky filler.

According to the invention <1>, a barrier layer made of a synthetic resin is not required, so that an excellent flexibility can be obtained. Further, it is not necessary to apply an adhesive to a nipple at the time of caulking. It is environmentally friendly and has excellent effects on oil resistance to lubricating oil and resistance to refrigerant permeation.

According to the invention <2>, even when the inner rubber layer has only the two-layer structure of the first inner rubber layer and the second inner rubber layer, the effect of the invention <1> can be improved. Can be obtained.

According to the invention <3>, the rubber polymer base material of the first inner tube rubber layer is made of NBR, H-NBR, CR, AC
By using either the M or the AEM rubber polymer, not only an excellent effect on oil resistance to lubricating oil is exhibited, but also a favorable effect on refrigerant permeation resistance is exhibited.

According to the invention <4>, the rubber polymer base material of the second inner tube rubber layer is made of an IIR rubber polymer, so that the refrigerant permeability can be particularly improved.

According to the invention <5>, the oil resistance as a main function of the first inner pipe rubber layer can be improved, and productivity is not impaired because the thickness is too large.

According to the invention <6>, a good balance between the refrigerant permeation resistance and the flexibility can be maintained.

According to the invention <7>, the adhesion between the first inner tube rubber layer and the second inner tube rubber layer can be further strengthened.

According to the invention <8>, in particular, the refrigerant permeation resistance can be enhanced.

[0025]

FIG. 1 shows a laminated structure of a refrigerant transport hose according to an embodiment of the present invention. It is necessary to select a material for the first inner tube rubber layer 1 mainly in consideration of oil resistance against lubricating oil. Also, if necessary, refrigerant permeability resistance,
The material is selected in consideration of moisture permeation resistance and flexibility. Specifically, NBR, H-NBR, CR, ACM
Alternatively, it is preferable that any one of AEM is used as the rubber polymer base material of the first inner tube rubber layer 1 and is made of a material excellent not only in oil resistance but also in refrigerant resistance. A rubber polymer base material as a main component may be blended with another rubber polymer in consideration of adhesiveness to the second inner tube rubber layer 2 and the like.
It is a matter of course that a compounding agent such as a processing aid, an antioxidant, a vulcanizing agent, a reinforcing agent, a vulcanization accelerator or the like which is usually used can be appropriately added to these rubber polymers.

Since the function of the first inner tube rubber layer 1 is mainly to improve the oil resistance, it is not necessary to make the thickness too large, and the thickness is set to such an extent that productivity is not impaired. Preferably 0.2 to
1.5 mm, more preferably 0.3 to
1.0 mm.

An adhesive layer (not shown) may be provided in order to make the adhesion between the first inner tube rubber layer 1 and the second inner tube rubber layer 2 stronger. By appropriately selecting the compounding system of the first inner pipe rubber layer 1 and the second inner pipe rubber layer 2 without providing an adhesive layer due to consideration, the rubbers can be directly bonded to each other by vulcanization or the like. It is preferable to do so. Further, the outer surface of the first inner tube rubber layer 1 may be subjected to a surface treatment such as a corona discharge treatment to improve the adhesive strength.

It is necessary to select the material of the second inner tube rubber layer 2 mainly in consideration of refrigerant permeation resistance, and further, in consideration of moisture permeation resistance, heat resistance and flexibility. Is preferred. That is, the second inner tube rubber layer 2 needs to have a function of supporting the internal pressure and preventing or reducing the refrigerant permeation and the invasion of moisture from the outside. Second
It is preferable that the rubber polymer base material be an IIR-based rubber polymer in order for the inner tube rubber layer 2 to have sufficient refrigerant permeability resistance while being rubber. The rubber polymer base material as a main component may be blended with another rubber polymer in consideration of the adhesiveness to the first inner tube rubber layer 1 and the like. Compounding agents such as an antioxidant, a vulcanizing agent, a reinforcing agent, and a vulcanization accelerator can be appropriately added as in the case of the first inner rubber layer 1.

It is preferable that a scaly filler is added to the second inner tube rubber layer 2 in order to further improve the refrigerant permeation resistance, so that the filler has a gas barrier function. The material of the scaly filler is not particularly limited as long as it is scaly, but silicates such as magnesium silicate, calcium carbonate, silica, alumina, magnesium and oxides thereof, Inorganic substances such as mica, clay, talc, and mica, which have a good filling property with a rubber polymer, are preferred. Particularly preferably, magnesium silicate (for example, manufactured by Nippon Mistron Co., Ltd., trade name: MI
STORON VAPOR).

The flaky filler is preferably blended in an amount of 60 to 200 parts by weight based on 100 parts by weight of the rubber component.
If the compounding amount is less than 60 parts by weight, the effect of reducing the refrigerant permeation amount is insufficient. It becomes difficult.

Conventionally, when the scale-like filler is blended, the surface condition of the rubber itself is roughened, so that the mandrel pull-out property has been extremely deteriorated. However, in the present invention, the scale is added to the second inner tube rubber layer 2. Such a problem does not occur because the filler is mixed. Also, the second inner tube rubber layer 2
In setting the thickness of the thickness, it is needless to say that the performance of suppressing the refrigerant permeation and moisture permeation is improved as the thickness is increased, in consideration of the permeation resistance, flexibility, etc. Preferably 0.5 to 2.5 mm,
More preferably, it is 0.8 to 1.5 mm.

The reinforcing layers 3 and 5 have a two-layer structure in the illustrated embodiment, and have a structure in which the intermediate rubber layer 4 is provided therebetween. However, the structure is not limited to two layers and may be a structure having three or more layers. . Further, the intermediate rubber layer 4 is provided as needed, and may be omitted. The properties required for the reinforcing layers 3 and 5 include heat resistance and fatigue resistance, as well as high strength and a high elastic modulus. Polyethylene terephthalate (PET) yarn can be suitably used. , Nylon, PEN (polyethylene naphthalate), aramid, aromatic PET yarn and the like can be suitably used, and if necessary, a mixed spun yarn combining two or more kinds may be used. When the elastic modulus of the reinforcing yarn is increased, the change in the hose inner diameter during pressurization is smaller than when a reinforcing yarn with a lower elastic modulus is used. As a result, the refrigerant permeation amount is suppressed.

The thickness and the number of knitting of such reinforcing yarns are designed in consideration of the safety factor with respect to the actual working pressure.
Preferably, two or more layers are wound in opposite directions, and if necessary, an intermediate rubber layer is provided between the layers as described above.
Further, a lower knitting layer (not shown) may be provided between the reinforcing layer 3 and the inner tube rubber layer 2. Further, if necessary, a pressing thread may be provided on the outer peripheral surface of the reinforcing layer. The thickness of the reinforcing thread is
Preferably 56-778 tex {500-7000D}
And more preferably 222 to 556 tex @ 2000
５5000 D｝. The number of reinforcing yarns depends on the diameter of the hose, but is preferably wound in a spiral such that 8 to 60, more preferably 12 to 36, alternately form a pair. In the present invention, the structure of the reinforcing layer is not limited to the spiral structure, and may be a known blade structure.

The reinforcing layers 3 and 5 thus formed are required to have both a function of supporting the pressure of the internal fluid and a function of suppressing a change in the inner diameter of the hose when subjected to the internal pressure, and have a high elastic modulus. Furthermore, it is necessary to be excellent in fatigue resistance and heat resistance.

The outer rubber layer 6 has a function of mainly protecting the reinforcing layer, and its material is selected in consideration of heat resistance, oil resistance, ozone crack resistance, flexibility, appearance performance and the like. Specifically, it is preferable to use ethylene propylene diene terpolymer rubber (EPDM) as the base polymer. In addition, CR, IIR, styrene-butadiene rubber (SBR), etc. may be used alone or in a blend. You may. The thickness of the outer rubber layer 6 is preferably in the range of 0.5 to 2.5 mm, and more preferably 0.5 to 2.5 mm.
It is within the range of 8 to 1.5 mm. Further, if necessary, a precking hole for venting the outer rubber layer 6 may be provided.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. The refrigerant transport hoses manufactured in Examples 1 to 6, the comparative example, and the conventional example are all of the type shown in FIG. In the first inner tube rubber layer 1 of the embodiment, the following Table 1
, NBR, H-NBR, CR, ACM, A
Either EM was used as the main rubber polymer, but none of them contained a flaky filler for improving gas barrier properties. Note that the thickness of the first inner tube rubber layer 1 is 0.1 mm.
5 mm.

The second inner rubber layer 2 was made of an IIR rubber polymer as the main polymer.
And in the comparative example, a scaly filler for improving permeation resistance (trade name: MISTO, manufactured by Nippon Mistron Co., Ltd.)
RON VAPOR) per 100 parts by weight of the rubber component
00 parts by weight were blended. The thickness of each of the second inner tube rubber layers 2 was 1.5 mm.

Each of the reinforcing layers 3 and 5 had a two-layer spiral structure, and an intermediate rubber layer 4 was provided therebetween. Reinforcement layers 3, 5
Used a reinforcing yarn of polyethylene terephthalate (PET), and wrapped the reinforcing yarn (444.4 tex) in a spiral such that 22 yarns were alternately paired.

The rubber polymer of the outer rubber layer 6 is EP
DM was used, and its thickness was 1.2 mm. In each of the hoses of Examples 1 to 6, the comparative example, and the conventional example, a priming hole for removing gas accumulated in the reinforcing layer is provided.

Examples 1 to 6, which were prototyped as described above,
The results of the evaluation tests performed on the refrigerant transport hoses of the comparative example and the conventional example are also shown in Table 1 below. The dimensions of the hoses shown in Table 1 are all the same (inner diameter 15.0 m).
m, outer diameter 23.6 mm), and all conditions except the material of the first and second inner pipe rubber layers were the same, and a trial manufacture and evaluation were performed.

[0041]

[Table 1] ：: excellent, ：: necessary and sufficient, △: usable, ×: not available * 1: Evaluation was made by measuring the load when wound around a mandrel of R100. * 2: 0.6 g / cm ³ of refrigerant (H
FC-134a) was sealed, left in a constant temperature bath at 80 ° C. for 96 hours, and the weight change was measured for 24 to 96 hours after the start of the test, and the value was defined as the refrigerant permeation amount. * 3: The volume change rate after immersion in PAG oil at 100 ° C. for 70 hours was evaluated. * 4: The volume change rate after immersion in Suniso 5GS oil at 100 ° C. for 70 hours was evaluated. * 5: Evaluated in consideration of productivity during hose production.

From Table 1 above, in Examples 1 to 4, and 6, all the evaluated items were able to obtain sufficiently usable results. In Example 5, since the flaky filler was not blended in the second inner tube rubber layer, the result was slightly inferior to the refrigerant permeation resistance. Further, in Examples 1, 4, 5, and 6, the PAG resistance tends to slightly decrease, but is not at a level that causes a problem in practical use. In Example 2, although there was a problem in terms of cost, it was found that the hose was excellent in performance.

On the other hand, in the comparative example, since the IIR rubber is used for the first inner tube rubber layer, although the refrigerant permeability is excellent, the mineral oil resistance is extremely deteriorated. Was.

[0044]

As described above, according to the present invention, the inner tube rubber layer is formed by the first inner tube rubber layer having excellent oil resistance.
At least 2 with the second inner tube rubber layer having excellent refrigerant permeation resistance
Due to the layer structure, despite the absence of a synthetic resin barrier layer, the amount of refrigerant permeation is small and the flexibility is excellent, and it is not necessary to apply adhesive to the nipple when caulking, and lubrication of the compressor It is possible to supply a refrigerant transport hose having no restriction on oil at low cost.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st inner pipe rubber layer 2 2nd inner pipe rubber layer 3,5 Reinforcement layer 4 Intermediate rubber layer 6 Outer rubber layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B32B 25/18 B32B 25/18 F16L 57/00 F16L 57/00 B F-term (Reference) 3H024 BA03 3H111 AA02 BA12 CB05 CB07 CB14 CB29 DA09 DA26 DB09 DB19 4F100 AK04A AK04J AK09B AK09J AK25A AK25J AK27A AK27J AK28A AK28B AK28J AK29A AK29J AK42 AK75 AL01A AL01B AN00A AN00B AN00D AN00E BA04 BA05 BA07 BA10A BA10D BA10E BA13 CA23B DA11 DE02B DE02H DG07 DH00C DH00E EH51 EJ64A GB31 JA20A JA20B JB07A JD01 JD05 JD05B JK13 JK17 YY00A YY00B

Claims (8)

[Claims] 1. A refrigerant transport hose comprising at least an inner tube rubber layer, a reinforcing layer, and an outer rubber layer sequentially laminated from an inner layer side, wherein the inner tube rubber layer is made of a different rubber polymer as a base material. A hose for transporting refrigerant, having a laminated structure of at least two layers, wherein the innermost layer is made of an oil-resistant rubber polymer as a base material, and the other layers are made of a refrigerant-resistant rubber-permeable rubber polymer. 2. The refrigerant transport hose according to claim 1, wherein said inner tube rubber layer comprises a first inner tube rubber layer of an inner layer made of a different rubber polymer and a second inner tube rubber layer outside thereof. 3. The rubber polymer base material of the first inner tube rubber layer is made of nitrile rubber (NBR), hydrogenated nitrile rubber (H).
-NBR), chloroprene rubber (CR), acrylic rubber (ACM) and ethylene acrylic copolymer (AEM)
3. The hose for transporting refrigerant according to claim 2, wherein the hose is selected from the group consisting of a rubber polymer. 4. The rubber polymer substrate of the second inner tube rubber layer is a butyl rubber (IIR) rubber polymer.
The hose for transporting refrigerant according to claim 1. 5. A thickness of the first inner tube rubber layer is 0.2 to 0.2.
The hose for transporting a refrigerant according to claim 2, which is 1.5 mm. 6. The second inner tube rubber layer has a thickness of 0.5 to 0.5.
The hose for transporting a refrigerant according to claim 2, which is 2.5 mm. 7. The refrigerant transport hose according to claim 2, wherein an outer surface of the first inner pipe rubber layer is subjected to a surface treatment. 8. The refrigerant transport hose according to claim 2, wherein a flaky filler is blended in the second inner rubber layer.