JPH0235290A - Low transmission hose - Google Patents

Abstract

PURPOSE:To reduce the transmission of refrigerant, gasoline, etc., and improve property against stress-caused cracks and flexibility by forming an inner tube with an inner layer of a stress crack preventing layer, a middle layer for preventing transmission, and an outer layer of rubber. CONSTITUTION:A hose comprises an inner tube, a reinforcement layer and an outer tube, with the inner tube being constituted with at least three layers of inner, middle, and outer layers. The inner layer as a stress crack preventing layer is formed with a polyamide-based resin containing nylon 11 or the like as an essential component. The middle layer as a transmission preventing layer is formed with an aromatic polyamide resin synthesized from methaxylerenediamine and adipic acid. The outer layer is made of rubber.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention provides a low permeation concave material having balanced practical performance for transporting refrigerants such as freon scum or fuels such as gasoline and diesel oil. Regarding hoses.

<Prior Art> Conventionally, the inner tube of the hose used for transporting refrigerant or fuel has been made of rubber that is oil resistant and has low permeability to refrigerant and fuel, such as nitrile rubber. There have been proposed hoses in which the inner tube is made of two layers of rubber and resin.

By the way, Freon gas, particularly dichlorodifluoromethane (hereinafter referred to as CFCl2), has been generally used as a refrigerant for coolers used in vibrating objects such as car coolers. However, it has become clear that CFCl2 destroys the ozone layer and is associated with skin cancer, and there is a trend toward banning the use of CFCI2. Therefore, monochlorodifluoromethane (hereinafter referred to as HCFC22), which has been used as a heating medium for stationary coolers and has low ozone layer destructive power, has been used for some time.
There is a movement to use it as an alternative.

However, HCFC22 has a major drawback in that it easily permeates NBR and nylon resins, which are commonly used in conventional hoses, compared to CFCl2.On the other hand, when other resins are used, they do not have the stress resistance and There is no limit to satisfying physical properties such as crack resistance.

Therefore, a hose that has low permeability of HCFC22 and also has physical properties required for a hose, such as scratch resistance, crack resistance, flexibility, etc., has not been known to date.

<Problems to be Solved by the Invention> The present invention has been made in view of the above facts and in response to industrial demands, and is designed to reduce the permeability and resistance of refrigerants such as HCF C22 and fuels such as gasoline. The purpose of the present invention is to provide a low permeability hose that has both stress crack resistance and flexibility.

Means for Solving the Problems> The present invention provides a hose consisting of an inner tube, a reinforcing layer, and an outer tube, in which the inner tube is made up of at least three layers: an inner layer, an intermediate layer, and an outer layer, and the inner layer has stress and crack prevention. The present invention provides a low permeability hose characterized in that the hose has a plurality of layers, the intermediate layer is a permeation prevention layer, and the outer layer is a rubber layer.

The present invention also provides a hose comprising an inner tube, a reinforcing layer, and an outer tube, in which the inner tube is composed of at least three layers, an inner layer, an intermediate layer, and an outer layer, the inner layer is a stress/crack prevention layer, and the intermediate layer is The present invention provides an H CF C22 low permeability hose, characterized in that the outer layer is a rubber layer, and the outer layer is a rubber layer.

In these inventions, the inner layer of the inner tube of the low permeability hose is a polyamide resin containing nylon 11 and/or nylon 12 as essential components, and the intermediate layer is an aromatic resin synthesized from metaxylylene diamine and adipic acid. polyamide resin (hereinafter referred to as aromatic polyamide resin)
Preferably, the outer layer is made of rubber.

Further, the inner layer of the inner tube of the low permeability hose has a 40 to 80%
A resin composition consisting of parts by weight of nylon 6 and/or nylon 6/66 copolymer, 5 to 30 parts by weight of nylon 11 and/or nylon 12, and 10 to 40 parts by weight of a polyolefin resin, and the intermediate layer is aromatic. It is preferable that the outer layer is made of rubber.

Furthermore, it is preferable that a nylon resin layer is formed between the intermediate layer and the outer layer of the inner tube.

Moreover, it is preferable that a polyamide 1-polyether copolymer layer is formed between the inner layer and the intermediate layer and/or between the intermediate layer and the outer layer of the inner tube.

In addition, a polyamide-polyether copolymer layer is formed between the inner layer and the intermediate layer of the inner tube and between the intermediate layer and the outer layer, and a polyamide-polyether copolymer layer is formed between the polyamide-polyether copolymer layer and the intermediate layer. , and a nylon resin layer is preferably formed at at least one location between the polyamide/polyether copolymer layer and the outer layer.

The present invention will be explained in detail below.

The low permeability hose of the present invention consists of at least three layers: an inner tube, an intermediate layer, and an outer layer.

The present invention aims to achieve the desired objectives of scratch resistance, low permeability, and flexibility in a well-balanced manner by composing these layers with appropriate materials. The configuration of each layer will be described below.

The material forming the inner tube is preferably a nylon resin, an aromatic polyamide resin, rubber, or a polyamide/polyether copolymer.

Table 1 shows typical properties of each of the materials.

Table 1 Very good or very flexible.

good or flexible.

Fairly good or somewhat flexible.

It's normal.

Slightly worse or slightly harder.

× Bad or hard.

× Very bad or very hard.

*1 Nylon resin a/nylon 6, nylon 6/6
6 copolymer, etc. *2 Nylon resin'o: Nylon 11
, nylon 12, etc. *3 Nylon resin 040-80 parts by weight of nylon 6 and/or still (J nylon 6/66 copolymer, 5-30 parts by weight of nylon 11 and/or nylon 12, and 10-40 parts by weight The low permeability hose of the present invention incorporates the characteristics of each material. The inner layer of the inner tube is a stress/crack prevention layer, the middle layer is a permeation prevention layer, and the outer layer is a rubber layer.

As is clear from Table 1, the inner layer of the hose inner tube, which is a crack prevention layer, is made of polyamide resin (nylon resin b) containing nylon 11 and/or nylon 12 as an essential component. Alternatively, 40 to 80 parts by weight of nylon 6 and/or
or nylon 6/66 copolymer, 5 to 30 parts by weight of nylon 11 and/or nylon 12, and 10 to 30 parts by weight of nylon 11 and/or nylon 12;
It is preferable to use a resin composition (nylon resin C) consisting of 40 parts by weight of a polyolefin resin.

Specific examples of polyamide resins (nylon resin b) containing nylon 11 and/or nylon 12 as essential components include nylon 11 and nylon 12 alone or in combination, 60% or more of nylon 11
and/or nylon 12 and less than 40% by weight of other polyamide resins, such as nylon 6. Examples include blend polymers with f.

Also, a resin composition comprising 40 to 80 parts by weight of Leelon 6 and/or nylon 6/66 polymer, 5 to 30 parts by weight of nylon 11 and/or nylon 12, and 10 to 40 parts by weight of a polyolefin resin. (Nylon Resin C) The polyolefin may be an α-olefin copolymer, and specific examples of the polyolefin include polyethylene, polypropylene, ethylene-propylene copolymer, and the like.

If necessary, other additives such as anti-aging agents may be added to the resin composition (for example, shoe-resistant agents 003 to 05).
% by weight and 3-10% addition of plasticizer).

The above blending ratios are limited in order to provide the resin composition with stress/crack resistance and flexibility.

As is clear from Table 1, it is preferable that the intermediate layer of the hose inner tube, which is a permeation-preventing layer, is made of aromatic polyamide resin.

The aromatic polyamide resin is synthesized from metaxylylene diamine and adipic acid and is represented by the general formula, and specific examples include MXD6 (manufactured by Toyobo Co., Ltd.).

Further, the rubber contributing to the flexibility used as the outer layer of the inner hose tube is a rubber composition.

Specifically, acrylonitrile butadiene rubber (N
B R), chlorosulfonated polyethylene (CSM)
, ethylene-propylene-diene terpolymer rubber (E
PDM), butyl rubber (IIR), chlorinated butyl rubber (0 sentence-IIR), brominated butyl rubber (Br-11
Rubber compositions such as rubber rubber (R), rubber rubber (CHR, CHC), and acrylic rubber (ACM) are considered, and the balance in terms of hose properties with the inner layer and intermediate layer, oil resistance, moisture impermeability, etc. are taken into consideration. Then, 1kuBR, CSM, EPD
M, CHR, CHC.

Rubber compositions of I R, CJ2-I I R, and Br-11R are preferred.

In addition to rubber, the rubber composition contains vulcanizing agents, fillers, reinforcing agents, plasticizers, anti-aging agents, etc., as well as vulcanization accelerators, softeners, and adhesive agents. , lubricant, quick dissection,
A dispersant, a processing aid, etc. may be blended.

Other materials used for the hose inner tube include polyamide resin (nylon resin a) containing nylon 6 and/or nylon 6/66 copolymer as an essential component, and nylon resins a and b in Table 1. Polyamide resins (nylon resin d) and polyamide-polyether copolymers other than those shown as , c may also be used.

Polyamide resin containing nylon 6 and/or nylon 6/66 copolymer as an essential component is CFC
Since the permeability of L2 is low, it has conventionally been frequently used as a tube material for hoses, and specific examples include nylon 6 and nylon 6/66 copolymers, each alone or in combination.

Examples of other polyamide resins (nylon; f-resin d) include nylon 8, nylon 10, and nylon 610.

Polyamide 1-/polyether copolymer is a block copolymer consisting of a polyamide segment or a polyether segment, and the polyamide [- segment is nylon 6, nylon 11, nylon 12, nylon 6/66 copolymer, From nylon 6/12 copolymer, etc., polyether copolymer 1~ consists of polytetramethylene glycol, polypropylene glycol, polyethylene glycol, etc.

By combining the components of polyamide segments 1 to 1 and polyether segments, copolymers exhibiting varying degrees of flexibility, melting point, and oil resistance have been obtained.

As a specific example, PEBAX 5533STOI, P
EIIAX5562MΔ00, PEBAX 5512M
N0O (manufactured by Atochem (HA) 0), Taiamide-P
AEE47 (manufactured by Teisel-Hüls), etc.

In the present invention, it is mainly used to improve interlayer adhesion, but this is because polyamide-polyether copolymer has good resistance to resins and rubber, and also has good chemical affinity. I can understand that.

As mentioned above, in the low permeability hose of the present invention, the inner layer of the inner tube is made of a polyamide resin (nylon resin b) containing nylon 11 and/or nylon 12 as essential components, which have stress and crack resistance. Or 40-80
A resin composition (nylon resin c ), the intermediate layer is preferably formed of aromatic polyamide resin as an opaque agent, and the outer layer is preferably formed of flexible rubber.

This combination forms an inner tube, and by forming a reinforcing layer and an outer tube on the outside, stress and crack resistance are improved.
The low permeability hose of the present invention can be obtained which has both the required physical properties as a hose such as flexibility and low permeability.

If you want to increase the flexibility of the hose, it is recommended to make the aromatic polyamide resin layer (intermediate layer) thinner.

Aromatic polyamide resins are generally coextruded with other resins. In order to make the aromatic polyamide resin layer thinner, for example, it is preferable to provide other resin layers on both sides and perform coextrusion. Therefore, between the intermediate layer and the outer layer, nylon resin a, 1 ), c, and d are preferably provided with layers of the various resins and blend polymers described above, or polyamide/polyether copolymers.

In addition, the above nylon resins a, b, c, d, aromatic polyamide resin, aromatic polyamide resin] 6. Grease, rubber, and the above nylon resins a, b, c, d.
The adhesion between the rubber and the rubber is rather weak.

On the other hand, polyamide-polyether copolymers have good adhesion to both of these.

Therefore, it is particularly preferable to provide a polyamide-polyether copolymer layer at a predetermined position between the inner layer and the intermediate layer and/or between the intermediate layer and the outer layer. This makes it possible to improve the mechanical strength, durability, etc. of the hose, as well as improve the structure of the hose inner tube.

Further, as a preferable example of the layer structure of the inner tube of the low permeability hose of the present invention, a polyamide 1-polyether copolymer layer is provided between the inner layer and the intermediate layer of the inner tube and between the intermediate layer and the outer layer. A layer of nylon resins a, b, c, and d is formed at at least one location between the polyamide polyether copolymer layer and the intermediate layer and between the polyamide polyether copolymer layer and the outer layer. It can be said that it has been formed.

In order to increase the flexibility of the hose, the intermediate aromatic polyamide resin layer is made thinner as mentioned above, but if the intermediate layer is thin, the adhesion between the three layers (inner layer, intermediate layer, and outer layer) and the adhesion between each layer must be reduced. In a hose inner tube having a five-layer structure in which a polyamide-polyether copolymer layer is provided between each layer to improve the impermeability, particularly the impermeability to HCFC22, there may be cases where the impermeability is insufficient. Therefore, in the above example, as shown in Table 1, next to the aromatic polyamide resin, a layer of nylon resins a, c, and d, which are impermeable to HCFC22, or a layer of nylon resin It is provided at least in one place between the copolymer layer and the intermediate layer and between the polyamide/polyether copolymer layer and the outer layer to compensate for impermeability.

As mentioned above, the nylon resin layer and the polyamide-polyether copolymer layer are formed between the inner layer and the intermediate layer of the hose inner tube, and between the intermediate layer and the outer layer in order to give the hose the required physical properties. Examples of their combinations include combining these materials to form an inner tube,
Table 2 shows the characteristics evaluated using a hose consisting of an inner tube, a reinforcing layer, and an outer tube manufactured by the method described below, or a JIS-1 Danher.

In addition, the thickness of each layer of the inner tube is set to 0 because the low permeability hose of the present invention has both the required physical properties as a hose such as stress/crack resistance and flexibility, and low permeability.
．． 02~050mm, preferably 005~0.25m
m, the middle layer is 0005 to 0.150 mm, preferably 0
．． 01~0.08mm, outer layer 0.02~0.50mm
, preferably 0.05 to 025 mm, and the other layers constituting the inner tube each have a thickness of 001 to 0.50 mm, preferably 002 to 0.25 mm. The total thickness of the inner tube (resin layer) excluding the outer layer of the inner tube is 0.8 m for practical reasons.
m or less, preferably 0.5 mm or less.

As a method for manufacturing the low permeation side hose of the present invention, known means can be applied, and an example thereof will be shown below.

Using multiple extruders prepared according to the type of resin, the inner tube of the hose is formed from a common multi-layer extrusion head that connects each extruder onto a mandrel that has been pre-applied with a mold release agent. Each resin is extruded to form a resin tube with a multilayer structure.

The mandrel with the resin duplex formed thereon is passed through a rubber extraction machine to extrude rubber onto the resin duplex to form a rubber inner tube layer. If necessary, a comb layer may be formed after applying an adhesive such as chlorinated rubber, phenol resin, or HRH to the surface of the resin duplex by coating or spraying.

The inner tube formed as described above is appropriately braided with reinforcing yarn using a braiding machine, and a rubber outer tube is formed on the inner tube using a rubber extruder. The mandrel on which the inner tube, reinforcing layer and outer tube were formed in this way was
The hose of the invention is obtained by heating under pressure in the temperature range of 140 DEG to 160 DEG C., vulcanizing the rubber layer, cooling and finally pulling out the mandrel.

<Example> The present invention will be specifically explained based on examples.

Hoses having the layer configurations shown in Table 3 (Examples 1 to 20, Comparative Examples 1 to 3) were manufactured by the method described above, and using these hoses, Freon gas permeation A amount, hose flexibility, and refrigerant reached the resin/81 fat interface and the adhesive durability of the resin was measured and tested in the following manner against a decrease in adhesiveness between the resins caused by expansion of the refrigerant due to temperature change.

In addition, JIS-1 dumbbells were manufactured, and using these dumbbells, stress and crack resistance were evaluated by the following method.

The results are shown in Table 4.

(Measurement method of Freon gas permeation amount) JRA200 of JRA standard (Japan Refrigeration and Air Conditioning Industry Association standard)
Conforms to 1.

The refrigerant was hosed into a fitting assembly hose with an inner diameter of 11.2 mm, a total thickness of 2 mm for the inner tube, and 2 mm for the outer tube, and a hose length of 045 m, with a reinforcing layer made of rayon between the inner tube and the outer tube. Enclose 06±01 grams per Icm3 of internal volume. Nu was exposed to a temperature of 100°C for 96 hours, and the weight loss (dregs permeation amount) between 24 and 96 hours was measured, and g/m
Convert the value to /72 hours.

The amount of CFCI 2 waste in rubber hoses is 20 to 25.
g/m/72 hours, and the refrigerant replacement cycle for the rubber hose is approximately 2 years.

On the other hand, in order to be maintenance-free, a replacement cycle of 10 years is required. However, in order to be maintenance-free, regardless of the type of gas, the amount of gas leakage must be
g/m/72 hours or less.

(Testing method for stress/crack resistance) Stress crank is a stress crank phenomenon of resin blades caused by metal ions (particularly zinc ions) eluted from piping or metal ions present in lubricating oil. Chlorides of metal ions, especially zinc chloride, are known to affect stress cracks.

50 on JTS-1 dumbbell (using extruded tube)
% zinc chloride aqueous solution was added dropwise, and the sample was left in a 100° C. atmosphere for 7 hours. Observation and dropping were repeated every 24 hours. Evaluation was made based on the number of days it took for a crack to appear at the center of the dropping point.

The number of days for cracks to occur in a resin hose duplex using a nylon 6 inner tube is 2 to 25 days, and the refrigerant exchange cycle for a resin hose duplex is approximately 2 years. On the other hand, in order to be maintenance-free, a replacement cycle of 10 years is required. Therefore, in order to be maintenance-free, it is necessary that the number of days in which cracks occur is 13 or more.

(Testing method for hose flexibility) Using a hose with an inner diameter of 11.2 mm, a total wall thickness of the inner tube of 2 mm, and an outer tube of 2 mm, and a reinforcing layer of rayon between the inner tube and the outer tube, The hose is bent along an arc with a predetermined radius and the bending stress is measured. The bending radius is measured starting from 10 times the outer diameter of the boss (IOD), and the bending stress is sequentially measured up to 3 times the outer diameter of the boss (n=2).

From the curve plotting the relationship between bending stress and bending radius obtained as a result, read the numerical value at the specified radius (4 times).

Generally, the flexibility of a rubber hose is at a level of 2.1 kgf, and some hoses with a resin duplex structure have a flexibility at a level of 6 to 7 kgf.

A hose with such a resin duplex structure is suitable for engine
When installing a device hebose in a narrow space such as a room, the workability is obviously poor, but empirically, workability is good if the bending stress is 3.5 kgf or less.

In addition, vibration absorption is also correlated with flexibility, but this relationship is non-linear, and when the bending stress exceeds about 35 kgf, the reaction force increases rapidly and the vibration absorption becomes extremely poor.

Therefore, the bending stress of the hose is preferably 3.5 kgf or less.

(Testing method for adhesion durability based on resin amount) This is a method for testing the adhesion durability between resins when a refrigerant is passed through a hose.

Freon is a gas at high temperatures, but becomes a liquid at low temperatures. When freon undergoes a phase change from gas to liquid due to temperature changes, the pressure within the hose changes, and hoses with poor resin adhesion will quickly develop blisters and delamination.

The test method is as follows.

The inner diameter is 11.2 mm, the total thickness of the inner tube is 2 mm, the outer tube is 2 mm, and the metal fitting assembly hose has a reinforcing layer of rayon between the inner tube and the outer tube, and refrigerant/freezer oil = 1
00715 composition was added in an amount of 70% of the internal volume of the hose, and both ends of the hose were closed. This was left at a high temperature (120°C) for 48 hours, and then at a low temperature (-30°C) for 12 hours.

One cycle consists of one cycle at high temperature and one cycle at low temperature (60 hours on the gold side), and the evaluation is based on the number of cycles until blistering occurs.

Experience has shown that in order to be maintenance-free, it is necessary that the number of cycles before blistering occurs is 10 or more.

As is clear from Table 4, the low permeability hose of the present invention is
All have low permeability to HCFC22, and have sufficient performance in stress/crack resistance, flexibility, and resin amount adhesion durability. Therefore, when used as a refrigerant transport hose for a car cooler or the like, it can be maintenance-free.

On the other hand, conventional hoses have high permeability to HCFC22, and cannot be said to have sufficient stress/crack resistance or flexibility.

<Effects of the Invention> According to the present invention, impermeability, stress/crack resistance,
A low permeability hose that also has flexibility can be obtained.

The low-permeability Bose of the present invention not only has low permeability to fuels such as gasoline, but also has low ozone layer destructive power. HCFC22, which could not be used as a refrigerant in coolers that are used to carry objects, has low permeability, and it has become clear that it destroys the ozone layer. It becomes possible to use C22.

Claims (12)

[Claims] (1) A hose consisting of an inner tube, a reinforcing layer, and an outer tube, wherein the inner tube consists of at least three layers, an inner layer, an intermediate layer, and an outer layer, and the inner layer is a stress/crack prevention layer;
A low permeability hose characterized in that the intermediate layer is a permeation prevention layer and the outer layer is a rubber layer. (2) In a hose consisting of an inner tube, a reinforcing layer, and an outer tube, the inner tube consists of at least three layers: an inner layer, an intermediate layer, and an outer layer, and the inner layer is a stress/crack prevention layer;
A monochlorodifluoromethane low permeability hose, characterized in that the intermediate layer is a permeation prevention layer and the outer layer is a rubber layer. (3) In claim 1 or 2, the inner layer of the inner tube is a polyamide resin containing nylon 11 and/or nylon 12 as an essential component, and the intermediate layer is an aromatic resin synthesized from metaxylylene diamine and adipic acid. A low permeability hose made of polyamide resin with an outer layer made of rubber. (4) The low permeability hose according to claim 3, wherein a nylon resin layer is formed between the intermediate layer and the outer layer of the inner tube. (5) The low permeability hose according to claim 3, wherein a polyamide-polyether copolymer layer is formed between the inner layer and the intermediate layer or between the intermediate layer and the outer layer of the inner tube. (6) The low permeability hose according to claim 3, wherein a polyamide-polyether copolymer layer is formed between the inner layer and the intermediate layer and between the intermediate layer and the outer layer of the inner tube. (7) In claim 3, a polyamide-polyether copolymer layer is formed between the inner layer and the intermediate layer and between the intermediate layer and the outer layer of the inner tube, and the polyamide-polyether copolymer layer and the intermediate layer are formed between the inner layer and the intermediate layer and between the intermediate layer and the outer layer. A low-permeability hose comprising a nylon-based resin layer formed at least in one place between the outer layer and the polyamide-polyether copolymer layer and the outer layer. (8) In claim 1 or 2, the inner layer of the inner tube is
A resin composition consisting of 40 to 80 parts by weight of nylon 6 and/or nylon 6/66 copolymer, 5 to 30 parts by weight of nylon 11 and/or nylon 12, and 10 to 40 parts by weight of a polyolefin resin, intermediate A low permeability hose whose layer is made of aromatic polyamide resin synthesized from metaxylylene diamine and adipic acid, and whose outer layer is made of rubber. (9) The low permeability hose according to claim 8, wherein a nylon resin layer is formed between the intermediate layer and the outer layer of the inner tube. (10) The low permeability hose according to claim 8, wherein a polyamide-polyether copolymer layer is formed between the inner layer and the intermediate layer or between the intermediate layer and the outer layer of the inner tube. (11) The low permeability hose according to claim 8, wherein a polyamide-polyether copolymer layer is formed between the inner layer and the intermediate layer and between the intermediate layer and the outer layer of the inner tube. (12) In claim 8, a polyamide/polyether copolymer layer is formed between the inner layer and the intermediate layer and between the intermediate layer and the outer layer of the inner tube, and the polyamide/polyether copolymer layer and the intermediate layer are formed between the inner layer and the intermediate layer of the inner tube. layer, and at least one place between the polyamide polyether copolymer layer and the outer layer,
A low permeability hose made of a nylon resin layer.