JPH02102986A - Hose for transporting cooling medium - Google Patents

Abstract

PURPOSE:To improve the flexibility of a hose and to effectively improve impermeability to moisture and gas by forming a multi-layer hose wall including a layer made by a specified elastomer material, a layer made by a specified chlorine elastomer and a layer made by polyamide resin. CONSTITUTION:An outer tube layer 3 is formed by elastomer material obtained from ethylene-propylene-diene ternary copolymer using 5-ethylidene-2-norbornane as diene component, with iodine number of 30-50mg/100mg and propylene content of 25-45wt%. The second inner tube layer 2 is formed by chlorine elastomer material with the combined chlorine quantity of 30-45wt%. The first inner tube layer 1 made by polyamide resin is formed about 0.05-1.0mm thick, and a fiber reinforcing layer 4 is formed by braided material of yarns, which is mainly composed of synthetic resin. The respective layers are sequentially laminated to obtain a hose for transporting a cooling medium, which is remarkably excellent in moisture impermeability, rich in flexibility and excellent in gas impermeability.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a hose for transporting a refrigerant, and particularly to a hose suitably used for piping of automobiles, air conditioners, and the like.

(Background Art) Conventionally, hoses for transporting refrigerants such as fluorocarbon gas have been integrally constructed of an inner tube layer, an outer tube layer outside the inner tube layer, and a fiber reinforced layer interposed between these two layers. A three-layer structure is 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. The outer tube layer is made of an elastomer or rubber-like elastic material obtained from an ethylene-propylene-diene terpolymer. (EPDM) or chloroprene rubber (CR). In addition, spiking holes extending from the outer surface to the fiber reinforcement layer are provided at appropriate locations on the outer tube layer, and through these spiking holes, the permeated fluorocarbon gas from the inner tube layer escapes to the outside.
This prevents it from accumulating between the layers of the hose wall. This is because if this permeated Freon gas stays within the multilayered hose wall, that portion will swell, causing separation between the eyebrows.

However, such hoses, whose entire structure is made of multiple rubber layers except for the fiber reinforcement layer, are flexible, so piping work is easy; sealing with fittings such as nipples is poor. Generally, rubber materials, especially rubber materials such as NBR and C3M used for the inner tube layer, have gas permeability, although they often have the advantage of maintaining airtightness. When a low molecular weight gas such as chlorofluorocarbon gas is used as a refrigerant, there is an inherent drawback that gas leakage occurs. In particular, in response to the recent social problem of destruction of the atmospheric ozone layer by fluorocarbon gas, reducing the amount of gas permeation has become the most important issue for refrigerant transport hoses.

For this reason, hoses have been considered that attempt to solve the above gas leakage problem by using polyamide resin, which has excellent gas impermeability, to form one of the hose constituent layers. In hoses like this, water permeates through the polyamide resin layer and other layers (rubber layers), making it difficult for water to permeate from the outside through the hose wall. When it mixes with the refrigerant in the hose, it causes ice locking in the refrigerant circulation path,
In addition to causing problems such as clogging and corrosion, there are inherent problems such as a loss of flexibility of the entire hose due to the rigid and hard resin layer. On the other hand, if the thickness of the polyamide resin layer is reduced in order to impart flexibility, the gas permeability to fluorocarbon gas will deteriorate.

In addition, in order to solve the problem of water permeation through the polyamide resin layer, Japanese Patent Laid-Open No. 60-91082 discloses
A fluorocarbon gas hose has been revealed that has a structure in which a resin layer made of a synthetic resin material with low water permeability is formed as an intermediate layer between a fiber reinforced layer and a gas-impermeable polyamide resin layer provided inside the fiber reinforcement layer. However, due to the presence of a rigid synthetic resin intermediate layer in addition to the polyamide resin layer, the entire hose lacks flexibility.
There are inherent problems such as difficulty in hose piping work.

Furthermore, in JP-A-6-1-6482, an EPDM layer is provided as an outer tube layer on the outside of the fiber reinforced layer, while an inner tube layer made of polyamide resin is provided inside the fiber reinforced layer for refrigerant gas permeation. A refrigerant transfer hose with a structure provided with a moisture permeation prevention layer made of a prevention layer and EPDM has been disclosed, but it is difficult to achieve sufficient moisture permeation prevention with EPDM, which has traditionally been used as a hose material. There it was.

In this way, all conventional hoses have advantages and disadvantages when used for refrigerant transportation, and in recent years there has been a demand for further improvements in refrigerant gas impermeability and moisture impermeability. None of them were satisfactory.

(Problem to be Solved) The present invention has been made against the background of the above circumstances, and its purpose is to provide a material that has excellent moisture impermeability, is highly flexible, and is free from fluorocarbons and the like. It is an object of the present invention to provide a refrigerant transport hose that is also excellent in gas impermeability to low molecular weight gases.

(Solution Means) In order to solve this problem, the present invention includes an inner tube layer, an outer tube layer outside the inner tube layer, and a fiber reinforcing layer interposed between both layers, and the inner tube layer has a plurality of layers. and one layer of the plurality of layers not in contact with the fiber reinforcing layer is formed of polyamide resin, of the plurality of layers constituting the inner tube layer. The layer in contact with the fiber reinforcing layer is formed of an elastomer material obtained from a heavy weight polymer having a bound chlorine content of 30 to 45% by weight, while the outer tube layer is formed of 5-ethylidene-2-norbornene as a diene component. and the iodine value is 30~
The propylene content is 25-4, which is 50mg/100■
The gist thereof is a refrigerant transport hose characterized by being formed from an elastomer material obtained from a 5% by weight ethylene-propylene-diene terpolymer.

Further, in the present invention, chlorosulfonated polyethylene or chlorinated polyethylene can be advantageously used as the chlorinated polymer, and furthermore, chlorosulfonated polyethylene or chlorinated polyethylene may be advantageously used as the chlorinated polymer, and further, the chlorinated polymer may be a chlorinated polyethylene that is in contact with the fiber reinforced layer among the plurality of layers constituting the inner tube layer. The elastomeric material forming at least one of the layers and the outer tube layer contains a white filler in a proportion of at least 15 parts by weight per 100 parts by weight of the polymer forming the elastomeric material. It is also characterized by being configured as follows.

(Operation/Effect) As described above, in the present invention, ethylene-propylene-propylene with a low iodine value using 5-ethylidene-2-norbornene as the diene component, which has been conventionally used as a rubber material for hoses. E obtained from a predetermined ethylene-propylene-diene terpolymer with an increased iodine value of 30 to 50 mg/100 mg compared to an elastomer (EPDM) material obtained from a diene terpolymer.
In PDM, the outer tube layer is formed, and the inner tube layer in contact with the fiber reinforcing layer is made of an elastomer material obtained from a chlorine-based polymer with a high amount of combined chlorine of 30 to 45% by weight. The flexibility of the hose can be improved by constructing a multilayer hose wall including a layer made of such a specific EPDM material, a layer made of a specific chlorinated elastomer, and a layer made of a polyamide resin. At the same time, it was possible to effectively improve water impermeability and gas impermeability.

In addition, in the present invention, a predetermined amount of white filler is advantageously added to the outer tube layer made of such specific EPDM elastomer material and/or the inner tube layer made of chlorine-based elastomer material. This further improves the water impermeability and refrigerant gas impermeability of the hose.

(Specific Structure) FIG. 1 shows one typical structure of a refrigerant transport hose according to the present invention.

Here, 1 is a first inner tube layer which is the innermost layer of the hose, and is made of a polyamide resin, in other words, a polyamide resin or a resin composition mainly composed of polyamide resin. Examples of this polyamide resin include nylon 6, nylon 11. Nylon 12° Nylon 612. Nylon 6/
66, nylon 6/66/610, etc., and various blends containing these nylons as main components, such as mixtures of nylon 12 and ethylene-vinyl alcohol copolymer (saponified ethylene-vinyl acetate copolymer), etc. is used as a polyamide resin.

And, located on the radially outer side of the first inner tube layer 1,
A second inner tube layer 2 is provided in contact with the fiber reinforcement layer 4,
Further, on the outside of the fiber reinforced layer 4, an outer tube layer 3 is formed to a predetermined thickness. Note that the outer tube layer 3 is provided with spiking holes at appropriate locations (not shown), similarly to conventional hoses.

In addition, in another example of the refrigerant transport hose of the present invention shown in FIG.
An inner rubber layer 5 made of a rubber material such as (chlorosulfonated polyethylene rubber) or CPE (chlorinated polyethylene rubber) is provided at a predetermined thickness. This inner one-sided rubber layer 5 constitutes one of the inner tube layers, and is made of a material with high rubber elasticity, and ensures sealing performance for joints such as nipples, and also serves as a first layer on the outside. It plays the role of protecting the inner tube layer l from metal deterioration.

In the hoses having these structures, in the present invention, first, the outer tube N3 is formed from a specific EPDM. This particular EPDM uses 5-ethylidene-2-norbornene as the diene component and copolymerizes it with ethylene and propylene so that the iodine value is 30-50 mg/100 mg/polymer, and has a propylene content. is obtained from an ethylene-propylene-diene terpolymer containing 25 to 45% by weight. In addition, the iodine value of such a terpolymer is J
If it is less than 30 mg/100 mg, it will be difficult to provide the hose with sufficient gas impermeability, and if the iodine value is less than 50 (2) If it exceeds 7100 (2), it becomes difficult to produce the terpolymer itself. Further, the propylene content in the terpolymer is 2
When the amount is less than 5% by weight or exceeds 45% by weight, a problem arises in that the water impermeability of the hose is reduced.

In addition, in order to obtain the desired EPDM elastomer by vulcanizing (crosslinking) the ethylene-propylene-diene terpolymer, various conventionally known methods can be used for the terpolymer. Compounding agents, such as vulcanizing agents (crosslinking agents)
, a vulcanization accelerator, a vulcanization aid, a processing aid, an anti-aging agent, a filler, and, if necessary, a softener, etc., are blended in the same manner as in the conventional production of EPDM to form a rubber composition. The elastomer is prepared and then crosslinked by heating to form the desired elastomer.

By the way, among such compounding agents, the vulcanizing agent (crosslinking agent) is
Usually 0.00 parts by weight per 100 parts by weight of the terpolymer.
It is blended in a proportion of 5 to 10 parts by weight, preferably 1 to 5 parts by weight, and various known compounds are appropriately selected and used. In particular, in the present invention, - It is preferable to carry out a crosslinking operation with peroxides rather than with sulfur, which improves the gas impermeability of the resulting layer of elastomer, especially the CFC gas impermeability. It can be improved.

In addition, examples of peroxides suitably used in the present invention include dicumyl peroxide, di-t-butyl peroxide, t-butyl peroxycumene, benzoyl peroxide, and 2,5-dimethyl-2,5-dimethyl peroxide. (t-
butylperoxy)hexane and the like.

In addition, at the time of peroxide crosslinking, as a crosslinking aid, for example, p
, p-dibenzoylquinone dioxime, quinone dioxime, triallylisocyanurate, ethylene glycol dimethacrylate, N,N'-m-phenylene bismaleimide, trimethylolpropane trimethacrylate, and the like.

When sulfur is used as a vulcanizing agent, sulfenamides, thiazoles, thiurams, dithiocarbamates, xanthates, etc. are used as vulcanization accelerators. Generally, the amount of these crosslinking aids or vulcanization accelerators is 0 to 100 parts by weight of the terpolymer.
．． A metal oxide such as zinc oxide is used as a vulcanization aid, and is generally 3 to 15 parts by weight per 100 parts by weight of the terpolymer. It will be used at a ratio of In addition, as a processing aid, fatty acids such as stearic acid and vegetable oils such as fatty oils are added at 0.5 to 5 parts by weight per 100 parts by weight of the terpolymer.
An anti-aging agent (anti-degradation agent) is usually added in an amount of 0.5 to 8 parts by weight per 100 parts by weight of the terpolymer. In addition, as this anti-aging agent, amine type, phenol type,
Examples include imidazole, metal carbamate, and wax.

Furthermore, fillers are added for the purpose of improving the physical properties of vulcanized products (crosslinked products), such as mechanical properties such as tensile strength, hardness, tear strength, and abrasion resistance. In the invention, especially silica, talc, clay, CaC
White fillers such as 0, among others AfgOs, Si
White talc based on OH and MgO is advantageously used, such white filler being one of the terpolymers.
00 parts by weight, at least 15 parts by weight or more, and the upper limit is about 200 parts by weight. By filling with such a white filler, EP
The water impermeability of the DM elastomer layer can advantageously be improved. Of course, along with such a white filler,
It is also possible to incorporate general-purpose fillers such as carbon black.

In addition, as a softening agent that can be added as necessary,
There are paraffinic, naphthenic, and aromatic process oils and ester plasticizers, and 100% of the terpolymer
It will be used in a ratio of 0 to 100 parts by weight.

By the way, in the present invention, the outer tube layer 3 is formed of a specific EPDM elastomer as described above, and the second inner tube layer 2 shown in FIGS. 1 and 2 is formed of a specific chlorine-based elastomer material. In this way, the performance of the hose, such as water impermeability and refrigerant gas impermeability, was improved. In the present invention, the chlorine-based polymer that provides the chlorine-based elastomer material forming the second inner tube layer 2 is advantageously:
Chlorosulfonated polyethylene or chlorinated polyethylene is used, and such chlorine-based polymers must have a large amount of bound chlorine, 30 to 45% by weight. However, if the amount of combined chlorine in such a chlorine-based polymer is less than 30% by weight, the water impermeability and refrigerant gas impermeability will deteriorate, making it impossible to impart sufficient performance to the hose. If the amount of combined chlorine exceeds 45% by weight, the rubber elasticity will deteriorate significantly,
Further, problems such as insufficient crosslinking occur.

In addition, in order to crosslink such a chlorinated polymer to obtain the desired chlorinated elastomer material, various conventionally known compounding agents, such as a crosslinking agent, a crosslinking accelerator, and a crosslinking promoter, are added to the polymer. Auxiliary agents, processing aids, anti-aging agents, fillers, and if necessary, softeners are mixed in the same manner as before to prepare a rubber composition, which is then crosslinked by heating to form the desired elastomer material. It will be done.

In addition, any of these compounding agents can be used in the same formulation as the EPDM elastomer material described above, but in particular at least 15 parts by weight of the polymer.
It is desirable to manufacture the intended chlorinated elastomeric material so that it contains a proportion by weight of white filler. By incorporating such a white filler, water impermeability can be effectively improved. Note that the upper limit of the amount of such a white filler to be blended is approximately 200 parts by weight per 100 parts by weight of the polymer, as in the case of EPDM described above.

In addition, in the hose configuration shown in FIGS. 1 and 2,
The thickness of each hose component layer will be determined appropriately depending on the type of material forming them, the thickness of the hose, its wall thickness, etc., but in a practical hose size, it is made of polyamide resin. The first inner tube layer 1 is generally 0.0
It will be formed at a thickness of 5 to 1.0 m.

If the thickness of the first inner pipe layer 1 becomes thinner than 0.05 mm, it becomes difficult to impart sufficient gas impermeability to the hose, whereas if the thickness exceeds 11 mm, it becomes difficult to provide the hose with sufficient gas impermeability. This is because, although it has excellent gas impermeability, the hose becomes more susceptible to leakage. Furthermore, even if the second inner tube N2 and outer tube layer 3 are made of a specific chlorine-based elastomer material or EPDM elastomer material in the present invention,
Although the thickness will be set appropriately, the former will generally be formed to a thickness of about 1 to 5II+1, and the latter to a thickness of about 1 to 4 mm.

Furthermore, the fiber reinforcing layer 4 is one that is used as is for ordinary rubber bors, and is formed by braiding, spiral knitting, etc. of yarns mainly made of synthetic fibers such as polyester fibers and aramid fibers. be.

Incidentally, such a refrigerant transport hose according to the present invention can be manufactured by sequentially laminating the above-mentioned layers, for example, in the following manner.

(a) Inner tube Ji (1
, 2, 5) A resin or rubber composition for forming is extruded from an extrusion molding machine to make a tubular body. By repeating this extrusion operation multiple times or by performing simultaneous extrusion molding, an inner tube layer consisting of multiple layers is formed. 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 multiple layers, the fiber-reinforced layer is formed by braiding or spiral-weaving the fiber-reinforced yarn. (4) is formed.

(c) After applying a predetermined adhesive (rubber glue, etc.) to the outer circumferential surface of the fiber reinforced layer (4) thus formed, a rubber composition for forming an outer tube layer is extruded onto it to form the desired layer. Outer canal layer (
3) is formed to a predetermined thickness.

(d) After the thus obtained laminated tube is vulcanized (crosslinked) and bonded together, the desired hose can be obtained by removing the mandrel. In addition,
The vulcanization conditions at this time are usually 1'40 to 170°
A temperature of approximately C and a vulcanization time of approximately 30 to 90 minutes will be employed.

The refrigerant transport hose obtained in this manner has a multilayer structure including a polyamide resin layer, a specific chlorine elastomer layer, and a specific EPDM layer as hose constituent layers. The specific combination and arrangement of these three layers ensures effective flexibility as a hose while simultaneously providing excellent gas impermeability and water impermeability, meeting the strict requirements of recent years. It is ideal as a car cooler or air conditioner hose.

(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 and percentages in the following examples are expressed on a weight basis unless otherwise specified.

The multilayered hose shown in FIG. 1 or 2 is
It was manufactured using the material configuration shown in Table 2. As mentioned above, the hose is manufactured by sequentially extruding the innermost layer of the hose to obtain a multi-layer laminated tube, and then heat-vulcanizing it to create a hose with an integrated multi-layer structure. . Further, the compounding composition of each rubber material used in Table 1 is as follows.

1) EPDMI 麙Kinsoko Shikin 1'' dish L polymer (ternary copolymer)...100FEF carbon black...
...80 paraffinic process oil...60 sulfur
......l Tetramethylthiuram disulfide...2 N-cyclohexyl-2-benzothiazylsulfenamide...l ZnO...5 Stearic acid... ...12) EPDM layer condition ■ [Polymer (ternary copolymer) FEF carbon black, talc paraffin-based process oil cumyl peroxide, ethylene glycol dimethacrylate... ZnO stearic acid 3) NBR Aikai NBR (AN=42%)・FEF carbon black・dioctyl phthalate・ZnO sulfur tetramethylthiuram disulfide ・LoIL・l 00・・20・100・・60・・・・5・・・・・・・3・・ ・ ・ ・ 5 ・ ・ ・ ・ ・ 1 IL port U ・ 100 ・ ・ 60 ・ ・ 10 ・ ・ ・ ・ 5 ・ ・ ・ ・ 1.

・ ・ ・ ・ ・ 2 N-Cyclohexyl-2-benzothiazylsulfenamide...1 4) CPEI [Distribution j] LoILCPE
(C1=25%)...100FEF carbon black...15PbO...20 Mg0...10 Dioctyl phthalate...5 Dicumyl peroxide...
...6 triallylisocyanurate...25)
CPE 2 Kai ■ Misaki Kai j” LoILCPE
(Cj!=35%)... 1OOFEF Carbon Black...15PbO...20 Mg0...10 Talc
...20 dioctyl phthalate...
...10 dicumyl peroxide...6 triallyl isocyanurate...26) C3M
ffi=40%)...100PbO...3
0 FEF carbon black...10 talc
・・・・・・20 Dibutylcarpitol adipate ・・・・・・15 N,N'-m-phenylene bismaleimide ・・・・・・・・・3 6-Eboxy2.2.4-)limethyl-1, 2-Dihydroquinoline...2 Dipentamethylenethiuram tetrasulfide...1 Table 2 For each hose obtained in this way, the flexibility, water permeability, and gas permeability of the hose are determined. evaluated. The results are shown in Table 3 below.

In addition, each evaluation was performed as follows.

A raw two-piece soft hose (inner diameter: 11.0m) was cut into a length of 300 mm, one end was fixed in a flat plate shape, the other end was bent, and the bending stress required to reach the flat plate was measured. I evaluated it. The smaller the value, the higher the flexibility.

Cut the water-permeable blood hose into a length of 500 mm, fill the hose with about 200 g of water-absorbing agent: molecular sieve, and then seal both ends. Next, this hose is left in an atmosphere of 60° C. and 95% relative humidity, and after 72 hours, it is opened and the water absorption weight of the molecular sieve is measured. The smaller the value, the better the water impermeability.

After cutting the mutually transparent municipal hose to a length of 500m+a and filling it with 40g of Freon 12 (R12), sealing both ends,
After leaving this for 72 hours at °C, the entire weight was measured and compared with the initial weight to determine the number of grams of Freon permeated and evaluated. The smaller the value, the better the gas impermeability.

As is clear from the above results, a chlorinated elastomer material with a predetermined amount of chlorine content and a predetermined iodine value according to the present invention,
A multi-layered hose Nα6~l consisting of each hose constituent layer using EPDM2 material containing propylene
O has excellent performance in terms of hose flexibility, moisture impermeability, and gas impermeability.

On the other hand, the hose Nα1, which does not have a polyamide resin layer, has excellent hose flexibility but is significantly inferior in water impermeability and gas impermeability.
In addition, even with hose configurations (N113 to 5) in which a nylon resin layer is provided as one of the inner tube layers and a layer made of conventional NBR or CPEI material is provided as another layer, moisture-impermeable It is recognized that the properties are poor or the gas impermeability is poor.

[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. l: 1st inner tube layer: 2nd inner tube layer: Outer tube layer: Fiber reinforcement layer: Inner surface rubber layer

Claims (1)

[Scope of Claims] Comprising an inner tube layer, an outer tube layer outside the inner tube layer, and a fiber reinforcing layer interposed between both layers, the inner tube layer is composed of a plurality of layers, and the inner tube layer is composed of a plurality of layers. In a hose in which one of the layers that is not in contact with the fiber-reinforced layer is formed of polyamide resin, the layer in contact with the fiber-reinforced layer among the plurality of layers constituting the inner tube layer is treated with combined chlorine. The outer tube layer is formed of an elastomeric material obtained from a chlorinated polymer having an amount of 30 to 45% by weight, while the outer tube layer is formed using 5-ethylidene-2-norbornene as the diene component and has an iodine value of 30 to 50 mg/10.
A hose for transporting a refrigerant, characterized in that it is made of an elastomeric material obtained from an ethylene-propylene-diene terpolymer having a propylene content of 25 to 45% by weight.