JP2002206036A - Colored rubber composition and pneumatic tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the ozone resistance and appearance. SOLUTION: This colored rubber composition is obtained by compounding 100 pts.wt. of a rubber component containing a diene-based rubber with 1-20 pts.wt. of an organic short fiber having 0.05-20 μm average diameter and 10-2,000 average length and is used for decoration of side part of tire, etc., as a colored rubber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color rubber composition (a rubber having a color other than black), and more particularly to a rubber composition having excellent ozone resistance and appearance. Further, the rubber composition of the present invention can be applied to a tire tread portion or a side portion, and particularly in the side portion, can be suitably used for decoration of lines, characters, and the like.

[0002]

2. Description of the Related Art Conventionally, when a rubber composition applied to a pneumatic tire or the like is used outdoors or the like, there has been an inconvenience that cracks are generated due to the influence of ozone and the like and durability is impaired. Therefore, conventionally, in order to prevent cracks due to ozone, 6-ethoxy-1,2-dihydro-2,2,4
-Trimethylquinoline, N-phenyl-N'-isopropyl-p-phenylenediamine, N-phenyl-N'-
Amine-based antioxidants such as (1,3-dimethylbutyl) -p-phenylenediamine and dithiocarbamate-based antioxidants such as nickel diethyldithiocarbamate have been used. Although these antioxidants have a certain effect in preventing ozone cracks, they have a disadvantage that they cannot be applied to color rubbers other than black because the appearance and color of the rubber are high due to the high coloring and contamination properties of the rubber. Was. In addition, 1,3-bis (dimethylaminopropyl) -2-thiourea or the like is used as a non-coloring and non-staining antiaging agent, but the ozone crack preventing effect is not sufficient.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a rubber composition which is excellent in weather resistance and high in appearance retention and is suitable for pneumatic tires and the like.

[0004]

In order to achieve the above object, the color rubber composition of the present invention has the following constitution. (1) A color rubber composition comprising a rubber component substantially composed of a diene rubber and an organic short fiber, wherein the organic short fiber is contained in an amount of 1 to 20 with respect to 100 parts by weight of the rubber component.
Parts by weight, and the average diameter of the organic short fibers is 0.1%.
05 to 20 μm, and the average length is 10 to 2000
μm. (2) The organic short fibers are characterized in that they are made of at least one of aliphatic polyamides, aromatic polyamides, polyesters, polyolefins, polyvinyl alcohols, and celluloses.

(3) The organic short fiber is characterized by being chemically bonded to the rubber component. (4) The organic short fiber is a maleic acid-modified polyolefin. (5) Each of the color rubber compositions further has a melting point of 100 to 1
A color rubber composition containing a polyolefin at 50 ° C. and wherein the organic short fiber is a thermoplastic polymer having an amide group in a main chain, wherein at least one of the thermoplastic polymer (A) and the diene rubber is used. Part (B), and each component of the polyolefin (C),
(A): (B): (C) = 1: 1 to 2: 0 to 1 is obtained by using a masterbatch prepared by kneading in advance at a weight ratio. The pneumatic tire of the present invention has the following configuration. (6) Each of the above color rubber compositions is applied to a tread. (7) Each color rubber composition is applied to a sidewall or a decorative portion of the sidewall.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail. The organic short fiber-containing rubber composition of the present invention is blended in an amount of 1 to 20 parts by weight with respect to 100 parts by weight of the rubber component. This is because the elastic modulus of the rubber composition increases. Examples of the rubber component include natural rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber, and butyl rubber. The organic short fibers have an average diameter of 0.05 to 20 μm and an average length of 10 to 2000 μm. This is to obtain an appropriate aspect ratio. If it is too large, the destructive strength will deteriorate.

The organic short fiber is an aliphatic polyamide-based fiber,
It is preferable that the material be made of at least one of aromatic polyamides, polyesters, polyolefins, polyvinyl alcohols, and celluloses. As aliphatic polyamides, nylon 6, nylon 6,6, nylon 6-nylon 6,6 copolymer, nylon 610, nylon 612, nylon 46, nylon 11, nylon 1
2, nylon MXD6, a copolymer of an aliphatic diamine and an aromatic dicarboxylic acid, and the like. Examples of the aromatic polyamides include Kevlar (trademark) and Twaron. Examples of the polyester system include polyethylene terephthalate, polybutylene terephthalate, and aromatic polyester. Polyolefins include syndiotactic 1,2 polybutadiene, polyethylene,
Examples thereof include polypropylene. Examples of the polyvinyl alcohol type include vinylon, and examples of the cellulose type include rayon. It is preferable that the organic short fibers are chemically bonded to the rubber component. This is because the breaking strength of rubber is hardly reduced. The organic short fiber,
A maleic acid-modified polyolefin is preferred because it can chemically bond to the rubber component.

It is preferable that the organic short fiber is made of a thermoplastic polymer having an amide group in the main chain, because it can be chemically bonded to a rubber component. In this case, from the viewpoint of productivity on an industrial scale, it is preferable that the organic short fibers are previously compounded as a malter batch containing a predetermined amount of a diene rubber and a predetermined amount of a polyolefin having a melting point of 100 to 150 ° C.

[0009] The color rubber composition of the present invention not only has excellent weather resistance, but also does not require the addition of a contaminating antioxidant, so that good appearance is maintained. Therefore, it can be suitably used as a surface member such as a tread or sidewall line of a tire or a decorative portion such as a character.

[0010]

EXAMPLES The present invention will be specifically described. Rubber compositions having the formulations shown in Table 1 were prepared. Vulcanization conditions are 150 ° C x 30
Minutes. Ozone resistance Measured according to JIS K6259-1993 ozone deterioration test method. Using a strip sample, ozone concentration 50pphm,
The measurement was performed at a temperature of 40 ° C. A 40% strain was applied, and the occurrence of cracks after 72 hours was confirmed. The evaluation criteria were based on the above. That is, the number of cracks is represented by A, B, and C, and the size and depth of the cracks are represented by 1 to 5. A: Small number of cracks B: Many cracks C: Numerous cracks 1: Not visible to the naked eye but can be confirmed with a magnifying glass of 10 times 2: Those that can be confirmed with the naked eye 3: Deep and relatively large cracks (less than 1 mm) 4 : Large and deep cracks (1 mm or more and less than 3 mm) 5: Those likely to cause cracks or cuts of 3 mm or more Appearance The vulcanized strip-shaped sample was left at room temperature, and the presence or absence of blooming after 60 days was confirmed. . In Table 1, ○ indicates that blooming has not occurred, and X indicates that blooming has occurred.

[0011]

[Table 1] It can be seen that the examples in which specific short fibers are blended can significantly improve ozone crack resistance. Although the mechanism is not clear, when the sample surface was observed with an optical microscope at a magnification of 100 times, a large number of very fine cracks of 0.05 mm or less were observed. It is considered that crack growth was suppressed. In addition, since it is not necessary to add a stain-resistant antioxidant, good appearance is maintained.

[0012]

As described above, according to the present invention,
A rubber composition having excellent ozone resistance and good appearance can be obtained. Further, the rubber composition of the present invention can be suitably used for the surface member such as a tread or Saidou _O Rugomu and decoration of the tire.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J002 AB012 AC011 AC031 AC061 AC081 BB002 BB003 BB032 BB033 BB122 BB123 BB171 BB172 BB173 BB212 BE022 CF002 CF062 CF072 CL002 CL012 CL032 CL062 FA042 GN01

Claims (7)

[Claims] 1. A color rubber composition comprising a rubber component substantially composed of a diene rubber and an organic short fiber, wherein the organic short fiber is contained in an amount of 1 to 20 parts by weight based on 100 parts by weight of the rubber component. And the average length of the organic short fibers is 0.05 to 20 μm and the average length is 10
A color rubber composition having a thickness of from 2000 to 2000 μm. 2. The organic short fiber according to claim 1, wherein the organic short fiber comprises at least one of an aliphatic polyamide, an aromatic polyamide, a polyester, a polyolefin, a polyvinyl alcohol, and a cellulose. Rubber composition. 3. The rubber composition according to claim 1, wherein the organic short fibers are chemically bonded to the rubber component. 4. The rubber composition according to claim 2, wherein the organic short fiber is a maleic acid-modified polyolefin. 5. The color rubber composition according to claim 1, further comprising a polyolefin having a melting point of 100 to 150 ° C., and wherein the organic short fiber has an amide group in a main chain. A color rubber composition comprising a thermoplastic polymer, wherein each component of the thermoplastic polymer (A), at least one part (B) of the diene rubber, and the polyolefin (C) is represented by (A): (B ): (C)
A color rubber composition obtained by using a master batch prepared by previously kneading at a weight ratio of 1: 1 to 2: 0 to 1. 6. A pneumatic tire, wherein the color rubber composition according to any one of claims 1 to 5 is applied to a tread. 7. A pneumatic tire, wherein the color rubber composition according to any one of claims 1 to 5 is applied to a sidewall or a decorative portion of the sidewall.