JPH02150590A - Refrigerant conveying hose - Google Patents

Abstract

PURPOSE:To secure such a refrigerant conveying hose that is rich in refrigerant impermeability, excellent in metal degradation resistance and affluent in flexibility by constituting one layer in monolayers or multilayers of an inner tube layer with a constituent making a specified resin blend body of its main ingredient. CONSTITUTION:One layer in both inner and outer side inner tube layers 1, 2 of a hose solidly constituted of these inner and outer side inner tube layers 1, 2 a fiber reinforced layer 4 and an outer tube layer 3 is made up of a constituent making a resin blend body consisting of a saponified compound of aliphatic polyamide resin, aromatic polyamide resin and an ethylene-vinyl acetate copolymer of its main ingredient. In consequence, owing to excellent refrigerant impermeability given by a suchlike resin blend body, the hose's refrigerant impermeability is improved as a whole. In addition, since this resin blend body is of material good for flexibility and also resisting material to a metallic ion and a metallic chloride being produced in a refrigerant system or a cooling passage, it is excellent in piping workability and, what is more, it is excellent in practical durability as well.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a hose for transporting refrigerant, and particularly to a hose suitably used for piping of an automobile's car cooler or air conditioner.

(Background Art) Conventionally, hoses for transporting refrigerants such as fluorocarbon gases have been constructed integrally with an inner pipe layer, an outer pipe layer outside the inner pipe layer, and a fiber reinforced layer interposed between these two layers. Layered structures are known. In such hoses, the inner tube layer is generally made of acrylonitrile-butadiene copolymer rubber (NBR) or chlorosulfonated polyethylene rubber (C3M), and the fiber reinforced layer is made of polyester fibers, rayon, etc. It is formed of a net-like body knitted using threads made of organic fibers such as fibers and nylon fibers, and the outer tube layer is made of ethylene-propylene-diene terpolymer rubber (EPDM) or chloroprene rubber (CR). is formed by.

By the way, such a multi-layered hose is entirely made of rubber material except for the fiber reinforcement layer, so it has flexibility suitable for piping work, and it also protects the refrigeration system during use. Generally, rubber materials Because it has gas permeability, refrigerant such as fluorocarbon gas that is circulated through the hose passes through the hose wall and leaks to the outside, gradually reducing the amount of refrigerant being circulated, thereby maintaining cooling capacity over a long period of time. Therefore, there is an inherent maintenance problem in that gas charging (refrigerant filling) must be performed frequently. In particular, in response to the recent social problem of destruction of the atmospheric ozone layer due to fluorocarbon gas, improving the gas permeability of such refrigerant transport hoses has become a major issue. In this way, conventional rubber hoses are flexible and highly resistant to metal deterioration, but
The impermeability to refrigerant gas was insufficient.

Therefore, in order to improve such refrigerant impermeability, it has been considered to construct one layer of the inner pipe layer of the hose from a resin material with excellent refrigerant impermeability, such as nylon 6, nylon 66, etc. Hoses with a layer made of polyamide resin such as those copolymers as one of the inner tube layers have been disclosed, but although such hoses have greatly improved refrigerant impermeability, they have poor durability. On the contrary, the metal deterioration property deteriorates, and there is a problem that it cannot be put into practical use. In addition, such polyamide resin is inferior to rubber materials in terms of flexibility, so the layer composed of it should be made as thin as possible, taking into account that such resin materials have excellent refrigerant impermeability. Even if it were constructed and used as one of the multilayer inner tube layers, it was still not as flexible as the rubber hose.

In addition, polyamide resins other than those mentioned above, such as nylon 11
Although the inner tube layer of the hose is made of a material such as nylon 12 or nylon 12, the metal deterioration resistance is good. In order to obtain the same refrigerant impermeability as a hose with an inner tube layer made of polyamide resin, it is necessary to increase the wall thickness of the inner tube layer by that amount. Therefore, the flexibility of the hose is significantly deteriorated, and there is a problem that it cannot withstand actual use.

As described above, all conventional hoses have advantages and disadvantages when used for refrigerant transportation, and in recent years, there has been a demand for further improvement in the impermeability of refrigerant gas, so none of them are satisfactory in terms of quality. There wasn't.

(Problem to be Solved) The present invention has been made against the background of the above, and its purpose is to provide a flexible material that is highly impermeable to refrigerants and has good resistance to metal deterioration. The purpose of the present invention is to provide a hose for transporting refrigerant that is rich in refrigerant.

(Solution Means) In order to solve this problem, the present invention provides an integral structure made of a single-layer or multi-layer inner tube layer, an outer tube layer outside the inner tube layer, and a fiber reinforced layer interposed between these two layers. The inner tube layer has a single layer or one layer of the inner tube layer made of a resin blend consisting of an aliphatic polyamide, an aromatic polyamide, and a saponified product of an ethylene vinyl acetate copolymer. The gist of the invention is a refrigerant transport hose characterized by being composed of a composition mainly composed of water.

In the present invention, preferably, the inner tube layer of the refrigerant transport hose as described above includes (a) an inner layer made of a composition mainly composed of the resin blend, and an outer layer made of a predetermined rubber material. Two-layer structure with layer or (b
) Consisting of a three-layer structure consisting of an inner layer and an outer layer made of a predetermined rubber material, and an intermediate layer made of a composition mainly composed of the resin blend interposed between these two layers, Furthermore, it is desirable that the composition is composed of the resin blend and a predetermined rubber component.

(Operations and Effects) As described above, the present invention uses a composition mainly consisting of a resin blend consisting of an aliphatic polyamide resin, an aromatic polyamide resin, and a saponified product of an ethylene-vinyl acetate copolymer. The desired hose is formed by forming a single inner tube layer or one of the multilayer inner tube layers, and the resin blend is applied with the resin blend. The excellent refrigerant impermeability of the hose improves the refrigerant impermeability of the entire hose, thereby effectively reducing the maintenance of gas charges in refrigeration or cooling systems using such hoses in piping systems. This means that it can effectively contribute to the problem of fluorocarbon gas pollution as a countermeasure.

Moreover, in the hose according to the present invention, the resin blend, which is the material constituting the inner pipe layer or one layer thereof, is a material with good flexibility, and the inner pipe layer or one layer thereof is made of a material with good flexibility and is Because it is a material that is resistant to metal ions and metal chlorides that are generated in

Furthermore, in the present invention, the inner tube layer has a two-layer structure, and the inner layer is made of a composition mainly composed of the resin blend, while the outer layer is a rubber layer made of a predetermined rubber material. The flexibility of the hose is further improved, and the simple structure has the advantage of providing excellent properties economically, and the inner tube layer has a three-layer structure.
By making the inner layer and the outer layer rubber layers made of a predetermined rubber material, and making the intermediate layer interposed between these two layers a layer made of a composition mainly composed of the resin blend. , it is possible to enjoy benefits such as improved sealing performance with joints such as nipples arranged at both ends of the hose.

Furthermore, by forming the composition of the present invention from a mixture of the resin blend and a predetermined rubber component, a layer that is more flexible than a layer consisting only of the resin blend can be formed in the inner tube of the hose. It can be formed as a constituent layer of a layer.

(Specific Structure) By the way, in the present invention, the aliphatic polyamide that provides the resin blend has a molecular structure composed only of aliphatic groups, and contains polycondensation of lactams and ω-amino acids, aliphatic carbon atoms, etc. Polycondensation of acid and aliphatic diamine,
Alternatively, they can be obtained by copolymerizing them, and blends of these polyamides can also be used in the present invention. In addition, specific examples of monomers that provide this aliphatic polyamide include ε-caprolactam,
Lactams such as enantlactam, capryllactam, lauryllactam, butyrolactam, γ-valerolactam; 6-aminocaproic acid, 7-aminohebbutanoic acid, 9
-ω- of aminononanoic acid, 11-aminoundecanoic acid, etc.
Amino acids; malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, hexadecane bilayer,
Aliphatic dicarboxylic acids such as hexadeceneniic acid, octadecanedioic acid, octadeceneniic acid, eicosaniic acid, eicosenniic acid, etc.; ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine,
Octamethylene diamine, nonamethylene diamine, decamethylene diamine, undecamethylene diamine, dodecamethylene diamine, tridecamethylene diamine, hexadecamethylene diamine, octadecamethylene diamine,
Aliphatic diamines such as 2,2.4 (or 2,4.4)-)limethylhexamethylene diamine can be mentioned.

Further, the aromatic polyamide, which is another component of the resin blend used in the present invention, has an aromatic ring in its molecular chain, and is formed by polycondensation of an aromatic dicarboxylic acid and an aliphatic diamine. It is obtained by polycondensation of dicarboxylic acids and aromatic diamines, or copolymerization thereof, and can also be used as a blend of such aromatic polyamides. The aliphatic diamines and aliphatic dicarboxylic acids used as monomers to form this aromatic polyamide are the same as those used to form the aliphatic polyamide, and the aromatic dicarboxylic acids include terephthalate and dicarboxylic acids. Acids such as isophthalic acid and phthalic acid are used, and as the aromatic diamine, xylylene diamine and the like are used.

Furthermore, the saponified product of ethylene-vinyl acetate copolymer, which is another component of the resin blend used in the present invention, is a copolymer obtained by copolymerizing ethylene and vinyl acetate in a predetermined ratio. On the other hand, those which have been subjected to a known saponification operation, and which have an ethylene content of 80 mol% or less and a saponification degree of vinyl acetate of 90 mol% or more, are preferably used. Become. Note that if the ethylene content or the degree of saponification of vinyl acetate is outside the above range, the refrigerant impermeability will be poor.

The blend ratio of aliphatic polyamide, aromatic polyamide, and saponified product of ethylene-vinyl acetate copolymer in the resin blend according to the present invention and the selection of monomers constituting each polyamide are determined according to the requirements of the intended hose. The blending ratio of aliphatic polyamide/aromatic polyamide is generally 90/10 to 20/80 by weight, although this will be done as appropriate depending on the properties of refrigerant impermeability, metal deterioration resistance, and flexibility. It is preferable that

If the proportion of aliphatic polyamide exceeds 90% by weight, flexibility and metal deterioration resistance will be good, but refrigerant impermeability will be poor, while if it is less than 20% by weight, refrigerant impermeability will be poor. This is because, although the properties are good, the flexibility and resistance to metal deterioration become poor.

In addition, the blending ratio of the blend of aliphatic polyamide and aromatic polyamide (polyamide blend)/saponified product of ethylene-vinyl acetate copolymer is 90/10 by weight.
It is preferable to set it as 30/70. When the proportion of the polyamide blend is 90% by weight or more, the flexibility is good, but the metal impermeability is poor;
If the amount is less than 30% by weight, the metal impermeability will be good, but the flexibility will be poor.

The resin blend body according to the present invention can be obtained by uniformly blending these three components by a known method. For example, after dry blending the respective pellets, the resin blend body according to the present invention can be obtained by blending the three components uniformly using a known method. It can be obtained by kneading.

In the present invention, such a resin blend is a main component of a composition constituting the inner pipe layer of a refrigerant transport hose, and for a resin blend containing the three constituent components, Furthermore, the rubber component (material) is an elastic body.
It is also possible to mix. By blending the rubber components in this manner, it is possible to obtain a hose inner tube structure layer that is more flexible than a resin blend. In addition, as a rubber component, ethylene-propylene-diene rubber (EPD
M), chlorinated polyethylene (CPE), chlorinated butyl rubber ((1-I IR), hydrin rubber (CHC, CH
R), etc., and the preferred blending ratio thereof is resin blend body/rubber component = 10,010 to 50,150 (weight ratio). The proportion of rubber component in the composition is 50% by weight
This is because, if it exceeds the above, although the hose inner pipe constituting layer can be made flexible, the refrigerant impermeability will be deteriorated. Further, in order to obtain a composition consisting of such a resin blend and a rubber component, kneading is performed using a screw extruder as described above, and at that time, if necessary, A vulcanizing agent for the rubber component and other known compounding agents are appropriately blended.

Further, the thickness of the single layer composed of the composition according to the present invention will be appropriately selected depending on the desired performance of the hose, such as flexibility and refrigerant impermeability.
Generally, a thickness of about 0.05 to 1.0 mm is appropriate. Note that if the thickness becomes thinner than 0.05 mm, the refrigerant impermeability decreases and the thin film strength becomes inferior.
Durability will decrease. On the other hand, when the thickness is 1 m or more, although the hose is excellent in refrigerant impermeability, the rigidity of the hose becomes high.

By the way, the layer composed of the composition according to the present invention described above can be formed as a single-layer inner tube layer or as an arbitrary layer of a multilayer inner tube layer. For example, as shown in FIG. The hose structure shown can be cited as a typical example of a refrigerant transporting hose according to the present invention. In this case, (2) is the inner tube layer which is the innermost layer of the hose, and is formed from a composition mainly consisting of the resin blend according to the present invention. Further, an outer inner tube layer 2 is provided on the radially outer side of the inner inner tube layer 1 and is in contact with the fiber reinforced layer 4. Furthermore, an outer tube layer 3 is provided on the outside of the fiber reinforced layer 4.
is formed to a predetermined thickness. This outer inner tube layer 2
has rubber elasticity and elastically supports the inner tube layer 1 made of the composition, and this highly flexible outer rubber layer further increases the flexibility of the hose. In addition, the advantages of low cost due to the simple structure have been achieved.

The outer inner tube layer 2 interposed between the inner inner tube layer 1 and the fiber reinforced layer 4 is usually made of a rubber material such as NBR or C3M, which is used for the inner tube material of a rubber hose. EPDM, Cj2=IIR, CPE, CHC
, CHR, or other rubber material.

The fiber reinforcing layer 4 may be one that is used in ordinary rubber hoses, and may be formed by, for example, braiding or spiral weaving of yarns mainly made of synthetic fibers such as polyester fibers and aramid fibers. be.

Furthermore, the outer tube layer 3 is the outermost layer of the hose, and is a layer that maintains the hose's basic characteristics such as weather resistance, heat resistance, and water permeability. C
I! , -IIR and the like are preferably used. Of course, it goes without saying that there is no problem even if a rubber material other than such rubber materials is used.

In another example of the refrigerant transport hose of the present invention shown in FIG. is provided at a predetermined thickness. This inner rubber layer 5 constitutes one of the inner pipe layers and is made of a material with high rubber elasticity, and its presence provides good sealing with joints such as nipples arranged at both ends of the hose. is now in good condition.

Note that the layer configuration of such a hose is appropriately selected depending on its use, and thereby it is possible to obtain a predetermined effect associated with each layer configuration.

In addition, in the hose configuration shown in FIGS. 1 and 2,
The thickness of the hose constituent layers such as the outer inner tube layer 2, the outer tube layer 3, and the inner rubber layer 5 is appropriately determined depending on the type of material forming them, the thickness of the hose, its wall thickness, etc. However, in a practical hose size, for example, the thickness of the outer inner tube layer 2 is about 1 to 3 mm. If the thickness is too thin, the hose will be soft when bent, but will be more likely to break (kinking); if it is too thick, the hose will be hard, although it will not easily break. In addition, the thickness of the outer tube layer 3 is generally about 1 to 3.5 mm in consideration of the water permeability of the hose, and the thickness of the inner rubber layer 5 is about 0.5 to 2.0 mm. It will be adopted in

By the way, such a refrigerant transporting hose according to the present invention can be manufactured by sequentially laminating the respective hose constituent layers, for example, in the following manner.

(a) An inner tube layer (
1, 2, 5) A resin or rubber composition for forming is extruded from an extrusion molding machine to form a tubular body on the mandrel. By repeating this extrusion operation multiple times or by performing simultaneous extrusion molding, as shown in FIGS. 1 and 2,
It is possible to form an inner tube layer consisting of multiple layers. In addition,
During such extrusion molding, an adhesive layer may be appropriately provided between each of the plurality of layers constituting the inner tube layer.

(b) Next, after applying an adhesive as necessary to the outer peripheral surface of the inner tube layer composed of a single layer or multiple layers,
The fiber reinforcing layer (4) is formed by braiding or spiral knitting the fiber reinforcing yarn.

(c) On the outer peripheral surface of the formed fiber reinforced layer (4),
After applying a predetermined adhesive (such as rubber glue), a rubber composition for forming an outer tube layer is extruded thereon to form a desired outer tube layer (3) to a predetermined thickness.

(d) After the thus obtained laminated tube is vulcanized (crosslinked) and bonded together, the desired bose can be obtained by removing the mandrel. In addition,
As the vulcanization conditions at this time, a temperature of about 140 to 170°C and a vulcanization time of about 30 to 90 minutes are usually adopted.

The thus obtained refrigerant transport hose uses a three-component resin blend consisting of an aliphatic polyamide resin, an aromatic polyamide resin, and a saponified product of ethylene-vinyl acetate copolymer as its inner tube layer constituent material. Due to the fact that a composition is used as the main component, it follows the characteristics specific to such a composition, while ensuring effective flexibility as a hose.
It has excellent refrigerant impermeability and metal deterioration resistance at the same time, making it ideal for car cooler and air conditioner hoses that meet the strict requirements of recent years.

(Examples) Below, some examples of the present invention will be shown to clarify the present invention more specifically, but the present invention is not limited in any way by the description of such examples. Needless to say, it is not something that can be accepted.

In addition to the following examples and the above-mentioned specific description, the present invention includes various changes, modifications, and changes based on the knowledge of those skilled in the art, as long as they do not depart from the spirit of the present invention. It should be understood that improvements and the like may be made.

Note that all parts, ratios, and percentages in the following examples are expressed on a weight basis unless otherwise specified.

Various types of multilayered hoses shown in FIG. 1 were manufactured using the material compositions shown in Table 1 below. In addition,
As mentioned above, the hose is manufactured by sequentially extruding the innermost layer of the hose to obtain a multi-layered laminated tube, and then heat-vulcanizing it to obtain an integrated multi-layered hose (inner diameter: 11 .Omm). Further, the compounding composition of each rubber material used in Table 1 is as follows. Furthermore, nylon 11 in the aliphatic polyamide resin is 11
It is a polycondensed metal of aminoundecanoic acid, and also nylon 6.
12 is a polycondensate of hexamethylene diamine and dodecanedioic acid.

1) NBR father gold bottom portion star gold 1” plate LNBR (AN=
42%)...100FEF carbon black...
...60 dioctyl phthalate...10ZnO
...5 Sulfur ...1 Tetramethylthiuram disulfide ...2 N-cyclohexyl-2-benzothiazylsulfenamide ...1 2) EPDM FEF carbon black...20 talc
...100 paraffin process oil.
...60 Dicumyl peroxide ...5 Ethylene glycol dimethacrylate ...3 ZnO ...5 Stearic acid ...13) (1-11
R sound arrangement precepts L gold 11 plates Y (1-I IR
(CJ!=1.0%)・100FEF carbon black...50 Paraffin process oil...10
ZnO...5 Anti-aging agent...2 Stearic acid
...1 Tetramethylthiuram disulfide ...1 Dibenzothiazyl disulfide ...1 4) CHR (epichlorohydrin/ethylene oxide = 50150 mo1) %)-100 Stearic acid, ,,,,l MgO...2 FEF carbon black...5゜Plasticizer
・・・・・・5 Red lead (Pb304) ・・・
...52-Methylcaptoimidacillin...1 Diphenylguanidine...0.5 For each hose thus obtained, the flexibility, refrigerant impermeability, and resistance to metal deterioration of the hose were evaluated. Each gender was evaluated. The results are shown in Table 2 below.

In addition, each evaluation was performed as follows.

Main two-person flexible hose (inner diameter: 11.0mm) 300mm or 40mm
The sample was cut to a length of 0III11, one end of which was fixed on a flat plate, the other end was bent, and the bending stress required to reach the flat plate was measured and evaluated. The smaller the value, the higher the flexibility.

At one point, the hose was cut to a length of 500 mm, filled with 40 g of Freon 12 (R12), sealed at both ends, and then
After being left for 2 hours, the entire weight was measured, compared with the initial weight, and the number of grams of Freon permeated was determined and evaluated. The smaller the value, the better the impermeability to refrigerant gas.

Immediately after punching out a No. 3 dumbbell from an inner layer tube made of a resin blend-based composition extruded onto a permanent mandrel with a weight capacity of 1. , an aqueous solution of zinc chloride (ZnCj!□) of various concentrations is dropped onto the dumbbell. Thereafter, the dumbbells were left in an oven at 120°C for 2 hours, and the dumbbells were checked for breakage.

Higher concentration of ZnCl2. The fact that there was no breakage even in an aqueous solution shows that the metal deterioration resistance is good.

As is clear from the above results, the inner inner tube layer (
Hose Nos. 1 to 7 with a multilayer structure having 1) have excellent performance in terms of hose flexibility, refrigerant impermeability, and metal deterioration resistance.

In other words, it is understood that the hose according to the present invention is extremely superior in refrigerant impermeability when compared with a conventional hose whose inner tube layer is made of only rubber material (No. 9). Furthermore, although a polyamide resin blend is used as the composition constituting the inner inner tube layer, it is also preferable that the resin blend contains a saponified product of ethylene-vinyl acetate copolymer as a constituent component, as in the present invention. It can be seen that the hose according to the invention is resistant to higher concentrations of metal ions when compared with the hose without (No. 8).

In the hose according to the present invention, the flexibility of the hose is not impaired at all due to these improvements in both characteristics.

[Brief explanation of the drawing]

1 and 2 are perspective views showing a typical example of a refrigerant transport hose according to the present invention. 1: Inner tube layer 3: Outer tube layer 5: Inner rubber layer 2: Outer inner tube layer 4: Fiber reinforced layer

Claims (1)

[Claims] A single-layer or multi-layer inner tube layer, an outer tube layer outside the inner tube layer,
A hose integrally constructed of a fiber reinforced layer interposed between both layers, a single layer of the inner tube layer
Or, one of the layers is composed of a composition mainly composed of a resin blend consisting of an aliphatic polyamide resin, an aromatic polyamide resin, and a saponified product of an ethylene-vinyl acetate copolymer. Features: Hose for transporting refrigerant.