JP2002013676A - Rubber composition for hose outer tube band hose using the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for a hose outer tube, capable of improving processability by suppressing adhesion of unvulcanized rubber and improving ozone resistance of vulcanized rubber and a hose using the rubber composition. SOLUTION: The rubber composition for a hose outer tube containing 2 wt.pts. or higher, based on 100 wt.pts. rubber containing butyl rubber, a quinolin base-aging preventing agent and the rubber composition is used in the outermost layer of at least the outer tube.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition for an outer tube of a hose and a hose using the same. More particularly, the present invention relates to a rubber composition for a vulcanized rubber which suppresses the adhesion of unvulcanized rubber to improve processability. The present invention relates to a rubber composition for hose outer tubes having improved ozone resistance and a hose using the same.

[0002]

2. Description of the Related Art Conventionally, rubber having low moisture permeability is used as an outer rubber of a hose for transporting a refrigerant used for an air conditioner of an automobile or the like so that moisture in the air does not penetrate into a refrigerant flowing through the hose. Have been. As such rubber, butyl rubber or halogenated butyl rubber has been used.

[0003] Further, since the outer tube rubber is disposed in the outermost layer of the hose, an antioxidant has been blended for the purpose of preventing ozone deterioration due to ozone in the air.
For example, N-isopropyl-N'-phenyl-p-phenylenediamine or N- (1,3-dimethylbutyl) -N
A phenylenediamine-based antioxidant such as' -phenyl-p-phenylenediamine is widely used. However, phenylenediamine-based antioxidants can cause discoloration of the rubber surface during use of the hose, or can easily migrate through the rubber and precipitate on the rubber surface, causing bloom and deteriorating the appearance. For the purpose of further improving the property, there is a problem that the compounding amount cannot be increased.

A quinoline-based antioxidant has been incorporated in a small amount (about 1 to 2 parts by weight per 100 parts by weight of rubber) as a heat-resistant antioxidant, but it is said that it has little effect on ozone resistance. And were used to the extent that they were supplemented.

[0005] Furthermore, butyl-based rubber has a large adhesiveness in an unvulcanized state. For example, the rubber adheres to equipment such as a mixer, a roll, and an extruder, and the workability and workability tend to be reduced. In particular, when the rubber was kneaded and molecular cutting progressed to increase the number of low molecular weight rubber polymers, the phenomenon became remarkable.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rubber composition for an outer tube of a hose in which the adhesion of an unvulcanized rubber is suppressed, the processability is improved, and the ozone resistance of the vulcanized rubber is improved. And a hose using the same.

[0007]

According to the present invention, there is provided a rubber composition for a hose outer tube which comprises at least 3 parts by weight of a quinoline antioxidant per 100 parts by weight of rubber containing butyl rubber.

Further, according to the present invention, there is provided the rubber composition for a hose outer tube, wherein the quinoline-based anti-aging agent is 2,2,4-trimethyl-1,2-dihydroquinoline and / or a polymer thereof. Is done.

Further, according to the present invention, there is provided a hose using the rubber composition for at least the outermost layer of an outer tube.

As described above, a quinoline-based antioxidant is added to a rubber composition containing a butyl rubber in an outer tube of a hose.
It has been found that by blending a large amount of 3 parts by weight or more with respect to parts by weight, it is extremely effective in improving ozone resistance which cannot be obtained by blending in a small amount. In addition, a large amount of the quinoline-based antioxidant can improve the processability and workability of the unvulcanized rubber at the same time, and it is considered that the butyl rubber polymer is particularly prevented from being cut during mixing. It has been found that it greatly contributes to the reduction of adhesion.
Furthermore, since the quinoline-based antioxidant hardly blooms, it has become possible to carry out the above-mentioned large amount compounding without impairing the appearance of the rubber.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, a quinoline-based antioxidant is added in an amount of 3 parts by weight or more, preferably 4 to 10 parts by weight, based on 100 parts by weight of a rubber containing butyl rubber. If the amount is less than 3 parts by weight, the effect of improving ozone resistance will not be seen, and if it is less than 2.5, the effect of lowering the adhesion of unvulcanized rubber will not be seen. On the other hand, if the amount exceeds 10 parts by weight, the modulus may decrease, or the cost may increase and the economic efficiency may deteriorate, which is not preferable.

Examples of the butyl rubber of the present invention include butyl rubber (IIR), chlorinated butyl rubber (CIIR), brominated butyl rubber (BIIR), and brominated isobutylene-p-methylstyrene copolymer (BIMS). It may be a mixture of two or more rubbers.

Further, the rubber composition of the present invention may be blended with another rubber in addition to the butyl rubber. For example, natural rubber (NR), polyisoprene rubber (IR),
Styrene butadiene rubber (SBR), polybutadiene rubber (BR), acrylonitrile butadiene rubber (NB
Various diene rubbers such as R) can be blended in an amount of 20% by weight or less in the total rubber polymer.

As the quinoline anti-aging agent, 2,2,2
4-trimethyl-1,2-dihydroquinoline and polymers thereof such as dimers, trimers and tetramers, 6-ethoxy-2,
2,4-trimethyl-1,2-dihydroquinoline and the like are exemplified. Among them, 2,2,4-trimethyl-1,
Preferably it is 2-dihydroquinoline and / or a polymer thereof.

The rubber composition of the present invention can be compounded with a compounding agent usually used in the rubber industry, if necessary.
Examples of the compounding agent include a reinforcing filler, a process oil, a vulcanizing agent, a vulcanization accelerator, a vulcanizing activator, a plasticizer, and the like.

The rubber composition of the present invention is produced by mixing the above components using a known rubber kneading machine, for example, a roll, a Banbury mixer, a kneader or the like.

The rubber composition of the present invention can be used in at least the outermost layer of an outer tube of a hose for transporting refrigerant and other various hoses. Accordingly, the rubber composition of the present invention may be used for the entire outer tube, or the outer tube may be used as two or more layers and used as the outermost layer.

[0018]

EXAMPLES The present invention will be further described with reference to the following examples, but it goes without saying that the scope of the present invention is not limited to these examples. Examples 1 to 3 and Comparative Examples 1 to 4 Each rubber composition having the composition (parts by weight) shown in Table 1 below was mixed with 150
Press vulcanization was performed at 45 ° C. for 45 minutes to form a sheet having a thickness of 2 mm. A test piece was punched from this sheet and subjected to the following tests. The adhesion was measured as follows using the unvulcanized rubber composition shown in Table 1.

[0019] 100% modulus (MPa), breaking strength
(MPa), elongation at break (%) Measured in accordance with JIS K6251. Ozone resistance According to JIS K 6259, the rubber was deteriorated for 96 hours under conditions of a temperature of 40 ° C., an ozone concentration of 1 ppm, and an elongation strain of 40%, and then the external appearance of the rubber surface was observed and judged as follows. ：: No crack was generated on the rubber surface. ×: Cracks occurred on the rubber surface.

[0020] Using the PICMA tack meter made by adhesion Toyo Seiki Co., winding the unvulcanized rubber sheet was heated to 100 ° C. in the drum, tack contact time of 0.1 sec with normal temperature of chrome plated plates, pulling The measurement was performed under the condition of a peeling speed of 30 mm / min. The smaller the value, the smaller the adhesion and the better the workability. The maximum value that can be measured by this measuring instrument is 1510 g
Therefore, in the case of 1510 g or more, it is specified as 1510.

[0021]

[Table 1]

The components used in Table 1 above were as follows. Chlorinated butyl rubber: Chlorobutyl 1066, Exxon Chemical Company SRF carbon black: Asahi No. 50, Asahi Carbon Co., Ltd. Quinoline anti-aging agent: 2,2,4-trimethyl-1,
2-Dihydroquinoline and its polymer mixture, Antigen RD-G, Sumitomo Chemical Co., Ltd. Phenylenediamine antioxidant: N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine (6C) , Santoflex 13, Flexis Vulcanization accelerator DM: dibenzothiazyl disulfide

As shown in Table 1 above, the rubber compositions of Comparative Examples 1 to 3 in which no or a small amount of a quinoline-based antioxidant were blended had insufficient ozone resistance and exhibited a quinoline-based antioxidant. In Comparative Example 4 in which a phenylenediamine-based antioxidant was blended instead of, the adhesion of the unvulcanized rubber did not decrease, and the appearance turned brown. In contrast, Examples 1 to 3 in which a quinoline-based antioxidant was blended in an amount of 3 parts by weight or more
In the rubber composition No. 3, both the ozone resistance and the adhesion of the unvulcanized rubber were improved, the appearance was black, and extremely good results were obtained.

[0024]

According to the present invention, the unvulcanized rubber is adhered to the rubber composition for an outer tube of a hose by adding at least 3 parts by weight of a quinoline-based antioxidant to 100 parts by weight of a rubber containing butyl rubber. It is possible to obtain a rubber composition for an outer tube of a hose in which the processability is improved by suppressing the force and the ozone resistance of the vulcanized rubber is improved, and a hose using the same.

Claims (3)

[Claims] 1. A rubber composition for a hose outer tube comprising at least 3 parts by weight of a quinoline antioxidant based on 100 parts by weight of a rubber containing a butyl rubber. 2. The method of claim 2, wherein the quinoline antioxidant is 2,2,
The rubber composition for an outer tube of a hose according to claim 1, wherein the rubber composition is 4-trimethyl-1,2-dihydroquinoline and / or a polymer thereof. 3. A hose using the rubber composition according to claim 1 for at least the outermost layer of an outer tube.