JPH0351596A - Hose for coolant - Google Patents

Abstract

PURPOSE:To achieve the superior softness, resistance for coolant permeability and superior adhesiveness and secure the durability for a long period by making a hose from an inner pipe, reinforcing layer, and an outer pipe and constituting the inner pipe from the inner and outer layers made of thermoplastic elastomer containing polyamide resin as continuous phase. CONSTITUTION:A hose consists of an inner pipe 1, reinforcing layer 2, and an outer pipe 3, and the inner pipe 1 consists of an inner layer 1a and outer 1b, and the both layers 1a and 1b are made of thermoplastic elastomer containing polyamide as continuous phase. The thermoplastic elastomer is made of the polymer blend which is made by dispersing epichlorohydrin rubber into polyamide resin or dispersing the ethylene unsaturated alkyl acrylate ester copolymers into amide resin, and the tensile strength in the ordinary state is desirably 20-200kgf/cm<2>. Therefore, the superior softness, resistance for coolant permeability, heat resistance, and low temperature impact can be obtained, and also adhesiveness is improved, and the superior durability can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The invention of this application relates to a refrigerant hose that is excellent in refrigerant permeation resistance, ml heat resistance, and low-temperature impact resistance.

[Prior Art] Refrigerant hoses used in automobile coolers, air conditioners, etc. are required to have flexibility, refrigerant permeability, heat resistance, low-temperature shock resistance, and the like.

Conventionally, this type of refrigerant hose has been made of acrylonitrile-butadiene rubber (NBR), as shown in FIG.
), a reinforcing layer (2) made of polyester fiber, and an outer tube (3) made of ethylene propylene-diene terpolymer rubber (EPDM). In addition, as shown in Fig. 4, the guard and inner tube (
1) In a refrigerant hose composed of a reinforcing layer (2) and an outer tube (3), the inner tube (1) is composed of an inner layer (1a) made of polyamide resin and an outer layer (1b) made of rubber such as NBrl or EPDM. There is something composed of

[Problem to be solved by the invention]

However, the refrigerant hose shown in Figure 3 above has excellent flexibility and low-temperature impact resistance, but is inferior in refrigerant permeation resistance and heat resistance, and furthermore, the inner tube (1) is recycled and used. The problem was that it was not possible to do so. Also,
The refrigerant hose shown in Fig. 4 above has refrigerant permeation resistance,
The inner layer (1a) and outer layer (1b) of the inner tube (1) have excellent
The problem was that the adhesiveness of the tube was poor, and the inner tube ( ) could not be recycled and used.

Therefore, the invention of this application is excellent in all of the above-mentioned properties required for refrigerant hoses used in automobile coolers, air conditioners, etc.
The object of this invention is to provide a refrigerant hose that has good adhesive properties (1b) and whose inner tube (1) can be recycled and used.

[Means to solve the problem]

Therefore, in the invention according to claim 1 of this application, the inner tube,
In the hose consisting of a reinforcing layer and an outer tube, the inner tube is composed of an inner layer and an outer layer, and both of these layers are made of a thermoplastic elastomer having a polyamide resin as a continuous phase.

Furthermore, the invention according to claim 2 of this application has the same structure as the invention according to claim 1, in which a thermoplastic elastomer is prepared by dispersing or crosslinking epichlorohydrin rubber in a boria resin. A dispersed polymer blend with a strength at 20% elongation of 20 to 200 kgf/cf in normal tensile properties as a hose inner pipe structure or sheet.
It is assumed that the value is within the range of fl.

Furthermore, in the invention according to claim 3 of this application, in the same structure as the invention according to claim 1, the thermoplastic elastomer is made of an ethylenically unsaturated acrylic acid alkyl ester copolymer having a functional group in the polyamide resin. is a polymer blend in which is dispersed or crosslinked, and the strength at 20% elongation in normal tensile properties as a hose inner pipe structure or sheet is within the range of 20 to 200 kgf/ci. .

Hereinafter, the invention of this application will be explained in detail based on the drawings.

FIG. 1 is a partially cutaway perspective view of a refrigerant hose according to the invention of this application, and FIG. 2 is a sectional view of the same refrigerant hose. In the figure, (1) is the inner tube, (2) is the reinforcing layer, and (3) is the outer tube, where the inner tube (1) is composed of the inner layer (1a) and the outer layer (lb). The inner layer (1a) and outer layer (lb) of the tube (1) are made of a thermoplastic elastomer having a continuous phase of boria resin.

The polyamide resin used in the invention of this application is
It is a thermoplastic resin having an amide bond -C○-NH- in its main chain, including Nylon 1con 6, Nylon 12, Nylon 6,
6, nylon 11, nylon 6,9, nylon 6,10
, nylon 6766, nylon 66/610, etc., but are not limited to these.

The crosslinking in the invention of this application involves blending other rubber into a thermoplastic resin matrix, highly crosslinking the rubber while kneading, and performing dynamic crosslinking in which the crosslinked rubber is microdispersed in the matrix. is preferred. Due to this dynamic crosslinking, the thermoplastic resin matrix exhibits thermoplasticity.

The epichlorohydrin rubber used in the invention of this application is a monopolymer of epichlorocohydrin (ECO
), or a copolymer of shrimp chlorohydrin and ethylene oxide, such as ethylene oxide/epichlorohydrin copolymer (ECO■), ethylene oxide/ebichlorohydrin/allyl glycidyl ether copolymer (
Examples include, but are not limited to, ECO■) and the like.

The ethylene-unsaturated acrylic acid alkyl ester copolymer according to the invention of this application is an ethylene/acrylic acid alkyl ester/maleic anhydride terpolymer (EA
R), a terpolymer of edylene/alkyl methacrylate/maleic anhydride, etc., but is not limited thereto.

The crosslinking agents used in the invention of this application include metal oxides such as zinc white and magnesium oxide, fatty acids such as stearic acid and oleic acid, amines such as jetanol acholine and hexamethylene diamine, zinc stearate, and stearin. Examples include metal salts such as sodium acid, but are not limited thereto.

Furthermore, the ratio of the boria resin and the shrimp chlorohydrin rubber in the invention of this application is such that flexibility, refrigerant permeation resistance,
In order to balance heat resistance, it is preferable to use 25 to 65 parts by weight of boria chloride resin and 35 to 75 parts by weight of epichlorohydrin rubber.

Furthermore, in the invention of this application, the ratio of the polyamide resin and the ethylenically unsaturated acrylic acid alkyl ester copolymer that has a functional group is determined by the polyamide resin in order to balance flexibility, refrigerant permeation resistance, and heat resistance. It is preferable to use 25 to 65 parts by weight, and 35 to 75 parts by weight of the ethylenically unsaturated acrylic acid alkyl ester copolymer having a functional group.

Further, the refrigerant hose of the invention of this application is manufactured by the following method.

First, an inner layer (1a) made of a thermoplastic elastomer having a polyamide resin as a continuous phase and an outer layer (1b) made of a thermoplastic elastomer having a polyamide resin as a continuous phase are coextruded, and the inner tube (L) is deformed in a certain shape. . Next, the inner tube (1)
A reinforcing layer (2) is formed thereon by a braiding machine. moreover,
Extrude the outer layer (3) onto the reinforcing layer (2) using a rubber extruder or plastic extruder. Incidentally, when the outer layer (3) is made of rubber, vulcanization is performed.

〔Example〕

Hereinafter, the refrigerant hose of the invention of this application will be explained in more detail based on Examples and Comparative Examples.

(Example 1) The inner layer (la) and outer layer (1b) of the inner tube (1) of the refrigerant hose of Example 1 had the composition shown in Table 1 and were manufactured by the following method.

The polyamide resin and rubber were charged into a kneader (Rheocoat manufactured by Haake) whose temperature was set near the melting point of the polyamide resin, and the number of rotations per coater of the kneader was set to 8 Or. p. It was kneaded as m. Further, stearic acid was added and kneaded for about 10 minutes, and then taken out as a blended resin.

The blended resin thus obtained could be press-molded as a thermoplastic resin, and a sheet with a thickness of 1 liter was obtained.

A laminated sheet of this sheet and the structural materials shown in Comparative Examples and Examples was produced by pressing. From this sheet JIS
A No. 2 Danher test piece of K 7113 was punched out, and a tensile test was conducted using this test piece. The results are shown in Table 2.

In addition, as a measure of flexibility, 2 in normal tensile properties
The strength at 0% elongation was used. This strength is 200
If it exceeds kgf/cnt, the tube/hose charge will be inflexible, and if it falls below 20 kgf/cJ,
When attaching a joint to a tube or hose, it cannot be crimped sufficiently, and refrigerant leaks from that part due to repeated deformation.

Next, the above blended resin is kneaded and granulated using a continuous kneading extruder, and then an inner layer (la),
Co-extruded as outer layer (lb), wall thickness approximately 2.0mm
The inner tube (1) was shaped. Using this, a heat resistance test and a low temperature impact test were conducted. The results are shown in Table 2.

Furthermore, after forming a reinforcing layer (2) of polyester fiber on the inner tube (1) using a braiding machine, an outer tube (3) of polyolefin resin was extruded and coated on the outermost layer to create a refrigerant hose. . A refrigerant permeation resistance test was conducted using this hose.

The heat resistance test, low-temperature impact test, and refrigerant permeation resistance test were each performed by the measurement methods shown below.

Refrigerant permeation resistance test (according to J/IsO Gate 321-77): Fill the metal assembly hose with 0.6 ± 0.1 g of refrigerant (Freon 12) per 1 c+fl of hose internal volume, and test at a measurement temperature of 100°C for about 1 month. The weight loss was measured periodically during this period.

Heat resistance test (according to JASO M 321-77): The inner tube (1) was aged at 120°C for 168 hours, and the presence or absence of cracks during subsequent bending was measured.

Items with cracks are indicated by ×, items without cracks are indicated by ○.
It was shown in

Low temperature impact test (SAE J 844 compliant): Inner tube (1)
The material was kept in a low-temperature thermostat set at an arbitrary temperature for 4 hours, and an impact test was conducted to show the temperature before cracking or destruction.

(Examples 2 to 5, Comparative Example 3) Inner pipes (1
), and the inner layer (1a) and outer layer (lb) of the inner tube (1) of each refrigerant hose in Examples 3 and 4 were also manufactured by the following method with the formulation shown in Table 1. . The inner layer (1a) of the inner tube (1) of the refrigerant hose in Examples 2 and 5 was manufactured in the same manner as in Example 1 above.

As in Example 1 above, after the polyamide resin and rubber were kneaded using a kneader, a crosslinking promoter for rubber, a filler, and a crosslinking agent were added while rotating the rotor. and,
Observe the torque increase due to crosslinking using a torque meter,
After confirming the completion of crosslinking, the blended resin was taken out. Note that the anti-aging agent was added after the crosslinking agent was added.

Since the blended resin made in this way can also be formed as a thermoplastic resin, the inner tube (1) and refrigerant hose are made in the same way as above, and tested for tensile test, heat resistance test, low temperature impact test, and refrigerant permeation resistance test. i8 autumn exam was held. The results are shown in Table 2.

(Comparative Examples 1 and 2) The inner tubes (1) of the refrigerant hoses of Comparative Examples 1 and 2 were made of polyamide resin having the formulation shown in Table 1. Then, a refrigerant hose was prepared in the same manner as above, and a tensile test, a heat resistance test, a low-temperature impact test, and a refrigerant permeation resistance test were conducted. The results are shown in Table 2.

(Comparative example 4) The outer layer (1) of the inner pipe (1) of the refrigerant hose of Comparative Example 4 9 lb) is not shown in Table 1 and is the NBR of the blended composition.

Then, an inner pipe (I) and a refrigerant hose were prepared in the same manner as above, and a tensile test, a heat resistance test, a low-temperature impact test, and a refrigerant permeation resistance test were conducted. The results are shown in Table 2.

(Comparative Example 5) Inner layer of inner pipe (1) of refrigerant hose of Comparative Example 5, (la)
was manufactured by the following method using the formulation shown in Table 1. The outer layer (1b) of the inner tube (l) of this refrigerant bow was made of NBR having the composition shown in Table 1.

As in Example 1 above, after the polyamide resin and rubber were kneaded using a kneader, a crosslinking promoter for rubber, a filler, and a crosslinking agent were added while rotating the rotor. and,
The increase in torque due to crosslinking was observed using a 1-lux meter, and after confirming completion of crosslinking, the blended resin was taken out. Note that the anti-aging agent was added after the crosslinking agent was added.

Since the blended resin prepared in this way can also be molded as a thermoplastic resin, an inner pipe (l) and a refrigerant hose were prepared in the same manner as above, and a tensile test, heat resistance test, Gion impact connection test, and the like were carried out. {A refrigerant permeation test was conducted.

Conclusion The results are shown in Table 2.

(Margins below) (Margins below) Table 1 Table 1 (Continued I) (Margins below) 15 (Margins below) 16 Table 1 (Continued ■) (Margins below) Table 2 (Margins below) 1 9 [Effects of the invention] This The refrigerant hose of the claimed invention has excellent flexibility and refrigerant permeation resistance, as is clear from the results of the tensile test, heat resistance test, low temperature impact test, and refrigerant permeation resistance test in comparison with the above examples and comparative examples. It has excellent properties in terms of , heat resistance, and low-temperature impact, making it extremely suitable for automobile coolers, air conditioners, and the like.

Furthermore, the refrigerant hose of the invention of this application has an inner pipe (1).
Since the adhesiveness between the inner layer (1a) and the outer layer (1b) of the tube is improved, it has excellent durability, and since the inner tube (1) can be recycled and used, it is also highly economical. becomes.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of a refrigerant hose according to the invention of this application. FIG. 2 is a sectional view of the refrigerant hose. 3 and 4 are cross-sectional views of conventional refrigerant hoses. (1)...Inner tube (la)...Inner layer (1b)
...Outer layer (2) ...Reinforcement layer (3) ...Outer tube

Claims (1)

[Claims] 1. A hose consisting of an inner pipe, a reinforcing layer, and an outer pipe,
A refrigerant hose characterized in that the inner tube is composed of an inner layer and an outer layer, and both of these layers are made of a thermoplastic elastomer having a polyamide resin as a continuous phase. 2. A polymer blend in which the thermoplastic elastomer is dispersed or cross-linked with epichlorohydrin rubber in a polyamide resin, and has a strength at 20% elongation in normal tensile properties as a sheet with a hose inner tube structure. ~
2. The refrigerant hose according to claim 1, wherein the refrigerant hose is within a range of 200 kgf/cm^2. 3. A polymer blend in which the thermoplastic elastomer is dispersed or crosslinked with an ethylenically unsaturated acrylic acid alkyl ester copolymer having a functional group in a polyamide resin, and the thermoplastic elastomer is a polymer blend in which the thermoplastic elastomer is dispersed or cross-linked in a polyamide resin, and the thermoplastic elastomer is dispersed in a polyamide resin and the thermoplastic elastomer is dispersed in a polyamide resin. Strength at 20% elongation in physical properties is 20 to 200 kg
2. The refrigerant hose according to claim 1, wherein the refrigerant hose is within a range of f/cm^2.