JPH068376A - Heat-resistant water hose - Google Patents

Abstract

PURPOSE:To enhance the heat resistance and pressure resistance of a water hose by forming inner and outer layers of the hose from a brominated copolymer and providing a reinforcing layer composed of p-aramide fibers between the inner and outer layers of the hose. CONSTITUTION:The inner layer 1 and outer layer 2 of a water hose are respectively formed from a copolymer (brominated IB-PMS) being an isobutylene/p- methylstyrene copolymer wherein a part of p-methylstyrene is brominated. A reinforcing layer 3 composed of p-aramide fibers of a material expressed by formula I is provided between the upper layer 1 and the outer layer 2. The p-aramide fibers expressed by formula I is spirally knitted to be arranged on the inner layer. The water hose thus produced is excellent in heat resistance and reduced in water permeability and can hold sufficient pressure resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant water hose, and in particular, automotive hoses such as radiator hoses, heater hoses and bypass hoses, temperature control hoses, temperature control hoses for industrial machines such as steam hoses for heating, etc. The present invention relates to a heat resistant water hose suitable for use in.

[0002]

2. Description of the Related Art Conventionally, as a water hose for transporting water, an inner layer and an outer layer are formed of sulfur vulcanized EPDM (ethylene / propylene / diene terpolymer), and an inner layer and an outer layer are provided for reinforcement. Generally, it has a structure in which a reinforcing layer made of PET (polyethylene terephthalate) is provided between and, for example, JP-A-3-1942.
In JP 81, EPDM is used for the inner and outer layers, and P is used for the reinforcing layer.
Water hoses using organic fibers such as ET, nylon, and rayon have been proposed.

EPDM or IIR is used for the inner and outer layers.
A water hose or a steam hose using (isobutylene / isoprene rubber) and a metal such as the above-mentioned organic fiber or steel wire or steel cord as a reinforcing layer is generally used for industrial machines.

[0004]

However, in recent years,
With the increasing performance of automobile engines, the temperature of the cooling water after cooling the engine rises and the temperature inside the engine room becomes high, so it is required to improve the heat resistance of the water hose. Has a problem that the heat resistance is not sufficient. Also, since the temperature of the cooling water rises, the amount of permeation from the hose increases, and in order to cope with this, it is possible to increase the capacity of the cooling water tank.
Such a method is not preferable because it requires a large space and increases the weight.

Also in industrial machines, conventional water hoses and steam hoses using EPDM or IIR as the inner and outer layers are inferior in heat aging resistance, and therefore, the frequency of hose replacement is high. Therefore, when used in applications where heat resistance is important, a hose consisting of a Teflon tube is used instead of a rubber hose, but since a Teflon tube is expensive and lacks flexibility, a rubber hose originally required to have flexibility. Substitution of is difficult.

The present invention has been made in view of the above circumstances.
An object of the present invention is to provide a heat-resistant water hose which has excellent heat resistance, small permeation of cooling water, and can maintain sufficient pressure resistance even when heat aging when cooling water is sealed.

[0007]

Means and Actions for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that in a heat-resistant water hose composed of an inner layer and an outer layer, isobutylene is formed in each of the inner layer or the inner layer and the outer layer. The following formula is used between the inner layer and the outer layer, using a copolymer obtained by brominated part of paramethylstyrene (hereinafter referred to as a brominated IB-PMS copolymer) with a copolymer of By providing the reinforcing layer composed of the para-aramid fiber represented by (1), the permeation of cooling water is small, and sufficient pressure resistance can be maintained even in heat aging filled with cooling water, so that good performance is obtained. I found that I could get a hose.

That is, the present inventor examined a hose having excellent heat resistance, a small amount of water permeation, and particularly good heat aging resistance. As a result, a copolymer of isobutylene and paramethylstyrene was prepared. Using a partially brominated copolymer as the inner layer of the hose, and as a reinforcing layer provided between the inner layer and the outer layer for reinforcing the hose, a para-aramid fiber represented by the following formula (1) is used. The present inventors have found that the above objects can be effectively achieved by using them, and have completed the present invention.

[0009]

[Chemical 2]

The present invention will be described in more detail below. In the heat resistant water hose of the present invention, a part of paramethylstyrene is brominated with a copolymer of isobutylene and paramethylstyrene for the inner layer or the inner and outer layers. It is formed of a copolymer, and a reinforcing layer made of para-aramid fiber represented by the following formula (1) is provided between the inner layer and the outer layer.

[0011]

[Chemical 3]

As such a hose, for example, a hose having a structure shown in FIG. 1 can be cited, which has a structure in which a reinforcing layer 3 is provided between an inner layer 1 and an outer layer 2. Here, the reinforcing layer 3
Is the one in which the para-aramid fiber of the formula (1) is knitted into, for example, a spiral shape (see FIG. 2) or a blade shape (see FIG. 3) and is disposed on the inner layer 1. In this case, a knit structure or a shisa system can also be used.

In the hose of the present invention, the inner layer 1 is formed of a brominated IB-PMS copolymer in the hose having such a structure. This brominated IB-PMS copolymer is disclosed in
As described in JP-A-150408, a part of PMS of the brominated IB-PMS copolymer is brominated due to crosslinking. In this case, the proportion of bromination is from 10 to 80% of the copolymerized paramethylstyrene, especially 2%.
It is preferably set to 0 to 70%. If this ratio is less than 10%, the crosslinking efficiency may be poor, and if it exceeds 80%, the heat resistance may be poor.

The weight ratio of isobutylene to paramethylstyrene is preferably 2 to 20% by weight, particularly 5 to 10% by weight of paramethylstyrene. If the proportion of paramethylstyrene exceeds 20% by weight, the Tg (glass transition point) becomes high and the properties of the rubber may be lost. If it is less than 2% by weight, the crosslinking efficiency may deteriorate.

The IB-PMS copolymer copolymerized and brominated at such a ratio can be easily crosslinked with ZnO or the like. The vulcanized product has good heat resistance because it does not have a double bond in the main chain, and has a structure similar to that of butyl rubber, and thus has low permeability to gas, water and the like.

In the hose of the present invention, the inner layer is formed of a copolymer obtained by brominated part of paramethylstyrene with the above-mentioned copolymer of isobutylene and paramethylstyrene, but the outer layer is formed with the same isobutylene. It is a copolymer with para-methyl styrene and is formed of a copolymer or other rubber in which a part of para-methyl styrene is brominated. Bromination of only inner layer 1
When it is formed of a B-PMS copolymer, the rubber forming the outer layer 2 includes NBR (acrylonitrile butadiene rubber), EPDM (ethylene / propylene / diene terpolymer), IIR (butyl rubber), CR (chloroprene rubber). ), Cl-IIR (chlorinated butyl rubber), CSM
(Chlorosulfonated polyethylene), ACM (acrylic rubber), AEM (ethylene acrylic rubber) and other rubbers, and rubbers obtained by blending two or more of these may be used.

The inner layer 1 preferably has a thickness of 1 to 4 mm, particularly 1.5 to 3.5 mm. The outer layer preferably has a thickness of 1 to 4 mm, particularly 1.5 to 3.5 mm.

The hose of the present invention further comprises a reinforcing layer made of para-aramid fiber between the inner layer and the outer layer. The reinforcing layer is required to have resistance to water deterioration at high temperatures, but generally used PET and nylon have poor resistance to water deterioration at high temperatures. From such a point of water deterioration resistance, the following formula (1) excellent in water resistance deterioration at high temperature is given.
It is intended to use a para-aramid fiber represented by, by knitting into a spiral structure or a blade structure as described above, it is preferable to form a reinforcing layer, but it is also possible to use a knit structure, a shisa method. it can.

[0019]

[Chemical 4]

[0020]

EXAMPLES The present invention will be specifically described below by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Example 1, Comparative Examples 1 to 3] The rubbers having the compositions shown in Table 1 were subjected to a heat aging test and a cooling water permeability test by the following methods.

[0022]

[Table 1] * 1: XP-50 (IB: 95% by weight, PMS: 5% by weight (brominated PMS: 36% by weight), manufactured by Exxon) * 2: EP33 (manufactured by Nippon Synthetic Rubber Co., Ltd.) * 3: EP11 (same as above) ) * 4: Butyl 268 (same as above)

Heat aging resistance test According to JIS-K6301 (vulcanized rubber physical test), 1
The rubber was allowed to stand in air at 50 ° C. and the elongation at break after air heat aging was measured. Cooling Water Permeability Test As shown in FIG. 4, cooling water (LLC / water = 50/50) 5 was put into an aluminum cup 4 to have a thickness of 0.5 mm.
The rubber sheet 6 is covered on the opening 7 of the cup 4, and the reinforcing wire mesh 8 is arranged on the sheet 6, and the cup 4, the sheet 6 and the wire mesh 8 are fixed with bolts 9, After passing through the oven for a predetermined time, the reduction amount of the cooling water due to heating was measured, and the value obtained by dividing this reduction amount by the area of the opening 7 was taken as the permeation amount.

The above results are shown in FIGS. 5 and 6. From the results shown in FIG. 5, the rubbers of Example 1 and Comparative Example 2 are excellent in heat resistance, and the rubbers of Comparative Examples 1 and 3 are inferior in heat resistance. I understand.

From the results shown in FIG. 6, it is understood that the rubbers of Example 1 and Comparative Example 3 have good resistance to cooling water, and the rubbers of Comparative Examples 1 and 2 have poor resistance to cooling permeation. .

Therefore, from the above results, brominated IB-P
It is recognized that by using the MS copolymer, a hose having both heat aging resistance and cooling water permeation resistance can be obtained.

[Example 2, Comparative Examples 4 and 5] The reinforcing yarn (1500 denier) shown in Table 2 was subjected to an underwater aging test by the following method. The results are shown in Fig. 7. In addition, in FIG. 7, E shows the test result of the reinforcing yarn of Example 2, F shows the comparative example 4, and G shows the test result of the reinforcing yarn.

[0028]

[Table 2]

[0029]

[Chemical 5]

Underwater Aging Test Each of the reinforcing yarns shown in Table 2 was embedded in the rubber of Example 1 shown in Table 1 and, after vulcanization, a ribbon shape (thickness: 1.5 mm) containing the reinforcing yarns along the length direction. , Width 4 mm) was cut out to obtain a sample. This sample was cooled with cooling water (LLC / water = 5
(0/50) and sealed in a cylindrical pressure-resistant container, taken out after a lapse of a predetermined time, and measured for tensile strength in a ribbon shape, and the measured value was measured for tensile strength of the sample before being immersed in cooling water. The value obtained by dividing was taken as the strong holding power. Since the elongation of the reinforcing yarn is much smaller than that of rubber, the contribution of rubber can be ignored.

From the results shown in FIG. 7, it can be seen that the reinforcing yarn of Comparative Example 5 has a large decrease in tensile strength, and the reinforcing yarn of Example 2 has particularly good characteristics.

[Example 3 and Comparative Examples 6 to 8] A rubber hose was produced using the rubber and the reinforcing yarn shown in Table 3. First, a rubber for forming the inner layer 1 was extruded, and a reinforcing yarn was knitted on the rubber in a spiral shape as shown in FIG. 2 to form a reinforcing layer 3, and the reinforcing layer 3 was further used for forming the inner layer 1. The same rubber was extruded to form the outer layer 2.

Next, the integrated product was inserted into a mandrel, and the shape was adjusted and vulcanized. The inner diameter of this hose is 21m
m and the outer diameter was 30 mm.

A performance confirmation test was conducted on the hoses manufactured in the above examples by the following method. The results are also shown in Table 3. Heat aging resistance test After the hose was left in the air at 150 ° C. for 500 hours and 1000 hours for heat aging, the hose was cooled to room temperature, and the hose was bent to determine the life. Permeation amount of cooling water from hose The permeation amount of cooling water was measured after the hose was left at 100 ° C. for 500 hours and 1000 hours. The measured value is 10% after the hose of the example is left at 100 ° C. for 500 hours.
It is represented by an index when 0 is set.

[0035]

[Table 3]

As a result of the heat aging test, there was no abnormality in Example 3 and Comparative Example 7, but in Comparative Example 6 and Comparative Example 8, the outer surface and the inner surface of the hose were cracked by bending after left for 500 hours. Regarding the permeation of cooling water, Comparative Examples 6 and 7 showed about 5 times the permeation amount, and Comparative Example 8 was at almost the same level as the Example.

From the above results, Comparative Example 7 having excellent heat resistance
The hose of Comparative Example 8 has a large amount of cooling water permeation and a small amount of cooling water permeation. The hose of Comparative Example 8 is inferior in heat resistance, and is implemented in terms of simultaneously having both heat aging resistance and low cooling water permeability. Only Example 3 satisfies both requirements, which is due to the combination of the rubber shown in Example 1 of Table 1 and the reinforcing yarn made of para-aramid fiber represented by the above formula (1). It can be seen that the results are obtained.

Regarding the hose of Example 3 and each hose in which only the reinforcing layer in this hose was replaced with PET similar to the conventional hose, cooling water (LL) was introduced into the hose.
(C / water = 50/50) was enclosed, and after heat treatment at 150 ° C. for 200 hours, a heat resistant water aging test of a hose for measuring pressure resistance was performed. As a result, the former burst at 50 kg / cm ² ,
The latter burst during pressure increase (20 kg / cm ² or less).

[0039]

According to the present invention, a copolymer of isobutylene and paramethylstyrene in which a part of paramethylstyrene is brominated is used for the inner layer or the inner and outer layers,
In addition, by interposing the para-aramid fiber reinforcing layer between the inner and outer layers, it is possible to obtain a hose that has a low permeation of cooling water and has sufficient pressure resistance even in heat aging filled with cooling water.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a heat resistant water hose of the present invention.

FIG. 2 is a diagram showing an example of the shape of a reinforcing layer in the hose of the present invention.

FIG. 3 is a diagram showing another example of the shape of the reinforcing layer in the hose of the present invention.

FIG. 4 is a schematic diagram illustrating a cooling water permeability test method for rubber used in Examples and Comparative Examples of the present invention.

FIG. 5 is a graph showing the results of a heat aging resistance test of rubbers of Examples of the present invention and Comparative Examples.

FIG. 6 is a graph showing the results of a cooling water permeability test of rubbers of Examples of the present invention and Comparative Examples.

FIG. 7 is a graph showing the results of an underwater aging test of the reinforcing yarns of Examples and Comparative Examples of the present invention.

[Explanation of symbols]

 1 Inner layer 2 Outer layer 3 Reinforcing layer

Claims (1)

[Claims] 1. A heat-resistant water hose comprising an inner layer and an outer layer, wherein the inner layer or the inner layer and the outer layer are copolymerized with isobutylene and paramethylstyrene, respectively, and a part of paramethylstyrene is brominated. A heat resistant water hose comprising a polymer and a reinforcing layer made of a para-aramid fiber represented by the following formula (1) provided between the inner layer and the outer layer. [Chemical 1]