JP2001247771A - Organic polymer composition and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic polymer composition excellent in the balance of static resistance, overheating prevention, low fuel consumption and braking performance without damaging reinforcing property, and a tire tread manufac tured by using the composition. SOLUTION: This organic polymer composition is characterized by containing silicon carbide powder having a >=30 m2 specific surface area, or the organic polymer composition is characterized by containing a mixed powder having a >=60 m2 specific surface area and containing 20-95% silicon carbide powder having a >=30 m2 specific surface area, 5-80% carbon powder and/or silicon oxide powder. The tire treads manufactured by using these organic polymer compositions are also provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic polymer composition containing a high specific surface area silicon carbide powder and a tire tread manufactured using the same.

[0002]

2. Description of the Related Art In recent years, in the automotive industry, in order to cope with environmental problems such as energy saving and resource saving, improvement of vehicle fuel efficiency and braking performance on wet road surfaces (hereinafter referred to as "wet skid resistance") are performed. The development of tire treads with increased tires is being actively pursued.

For example, in evaluating the viscoelastic spectrum of a tire tread rubber, a loss factor (hereinafter referred to as “tan δ”) is used.
That. It is known that tan δ at 50 to 70 ° C. is reduced to improve fuel economy, and tan δ around 0 ° C. is increased to improve wet skid resistance (Ryo Muramatsu, Hideaki Takahashi: See Japan Rubber Association, 72, p705 (2000)). In order to balance tan δ in both temperature ranges with good balance,
Conventionally, silicon dioxide powder has been filled together with an expensive silane coupling agent. Here, the silane coupling agent is used in combination with the silicon dioxide powder.
High cohesiveness and poor compatibility with rubber, wear resistance,
This is because the fracture resistance and the like are inferior to those of the tire tread filled with the carbon powder, so that it is improved.

However, since the silicon dioxide powder is also non-conductive, the resistance increases as the filling rate of the tire tread increases, and the charge during traveling increases. For example, when a passenger gets on and off the vehicle, he / she feels discomfort. There is a risk that the electronic components in the vehicle may be damaged, or sparks may occur during refueling.

In order to solve this problem, the content of silicon dioxide powder may be reduced. However, the reduction of the filling rate naturally leads to low fuel consumption performance and poor wet skid resistance. Absent. On the other hand, various attempts to solve the problem by improving the tire structure have been proposed, but the performance and cost are indeterminate.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to control the balance of tan δ in both temperature ranges of a tire tread to the same level as that of silicon dioxide powder, and to further improve the charging. An object of the present invention is to provide an organic polymer composition having an excellent prevention effect and a large reinforcing property, and a tire tread using the same.

[0007]

That is, the present invention provides an organic polymer composition comprising a silicon carbide powder having a specific surface area of 30 m ² / g or more. In particular, 20 to 95% of silicon carbide powder having a specific surface area of 30 m ² / g or more.
And a mixed powder containing 5 to 80% of carbon powder and / or silicon oxide powder and having a specific surface area of 60 m ² / g or more. Further, the present invention is a tire tread manufactured by using the organic polymer composition as a rubber composition.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

In the present invention, the reason why silicon carbide powder is used as a filler is that silicon dioxide powder and a silane coupling agent are used in combination to have a small antistatic effect and a disadvantage of being expensive, and to use carbon powder. This is to reduce the disadvantage that the tan δ of both temperature regions cannot be balanced in the case. It is preferable that the silicon carbide powder is as fine as possible in order to obtain a sufficient reinforcing effect, and it is necessary that the specific surface area is 30 m ² / g or more.

In the present invention, the silicon carbide-based powder may be used alone. However, when used together with the carbon powder and / or silicon oxide, the antistatic effect and the t of both temperature ranges are improved.
The balance of anδ can be enhanced to a higher degree. Also, a cost reduction effect can be expected. In this case, it is important that the specific surface area of the mixed powder containing the silicon carbide-based powder and the carbon powder and / or silicon oxide is 60 m ² / g or more, and that the ratio thereof is set to the silicon carbide powder 20.
-95%, preferably 30-70%, carbon powder and / or silicon oxide powder 5-80%, preferably 30-70%.
%.

The high specific surface area silicon carbide powder used in the present invention can be obtained by further pulverizing a commercial product. As the carbon powder, acetylene black, furnace black, lamp black, oil black, thermal black, graphite powder, etc. are used. As the silicon oxide powder, silicon dioxide, fused silica, precipitated silica, fumed silica, monoxide, etc. Silicon or the like is used.

The above-mentioned mixed powder containing silicon carbide powder can be prepared by mixing silicon carbide powder, carbon powder and silicon oxide powder in appropriate amounts, and for example, as described in Japanese Patent No. 1703767. As described above, it can also be produced by decomposing a hydrocarbon gas in a reactor and reacting and synthesizing the generated suspended fine carbon powder and silicon monoxide gas in a non-oxidizing atmosphere. The resulting composite is heated to remove the carbon component, and then pickled to obtain a specific surface area of 3
Silicon carbide powder of 0 m ² / g or more can be obtained.

The organic polymer used in the present invention is a rubber and / or a resin. The ratio of the two depends on the application, but 100 parts of rubber and / or resin (parts by mass; the same applies hereinafter).
About 30 to 800 parts. A blender or a mixer is used for the mixing, and the molding is performed by a heating roll, a kneader, a single-screw or twin-screw extruder, or the like.

For rubber tread, natural rubber (NR) and diene rubber are used. As the diene rubber, styrene butadiene rubber (SBR),
Polyisoprene rubber (IR), polybutadiene rubber (B
R) and the like can be used. In addition, silicone rubber, chloroprene rubber, and the like can be used.

As the resin, epoxy resin, silicone resin, phenol resin, melamine resin, urea resin, unsaturated polyester, fluorine resin, polyimide, polyamide such as polyamide imide, polyether imide, etc.
Polyester such as polybutylene terephthalate, polyethylene terephthalate, polyphenylene sulfide, wholly aromatic polyester, polysulfone, liquid crystal polymer, polyether sulfone, polycarbonate, maleimide modified resin, ABS resin, AAS (acrylonitrile acrylic rubber / styrene) resin, AES (acrylonitrile)・ Ethylene propylene diene rubber-styrene) resin and the like can be used.

The following components can be further added to the organic polymer resin composition of the present invention.

Coupling agents: epoxysilanes such as γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, aminopropyltriethoxysilane, ureidopropyltriethoxysilane, N- Aminosilanes such as phenylaminopropyltrimethoxysilane; hydrophobic silane compounds such as phenyltrimethoxysilane, methyltrimethoxysilane and octadecyltrimethoxysilane; and mercaptosilane.

Flame retardant aids: Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅
etc.

Flame retardant: halogenated epoxy resin, phosphorus compound, etc.

Colorant: iron oxide, dye, pigment and the like.

Release agents: natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, paraffin and the like.

[0022]

The present invention will be described more specifically with reference to examples and comparative examples.

Examples 1 to 5 Comparative Examples 1 to 3 A mixed powder containing silica and carbon was mixed in a resistance electric furnace for 18 hours.
Heated to about 00 ° C. to generate silicon monoxide gas, which was supplied to a reactor using a carrier gas together with acetylene gas, and synthesized to produce developed powders A and B. Table 1 shows the types of the carrier gas and the synthesis temperatures. Developed powder A, B
Was measured for composition and specific surface area as follows.
Table 1 shows the results.

(1) Composition: heating at 650 ° C. in the atmosphere to eliminate the carbon component, calculating the carbon content from the mass reduction rate, and after heat treatment, pickling with hydrofluoric acid and nitric acid; Only the silicon carbide content was calculated from the yield, and the remainder was regarded as the silicon oxide content. (2) Specific surface area: measured by BET one-point method by nitrogen gas adsorption. Further, after heat treatment of the developed powders A and B in the air at 650 ° C., they are pickled with hydrofluoric acid and nitric acid, and only silicon carbide components are used as the developed powders A-1 and B-1, respectively. Was.

[0025]

[Table 1]

Each material was mixed at the compounding ratio shown in Table 2 to prepare an organic polymer composition (rubber composition). This was kneaded and vulcanized to form a rubber sheet, and the state characteristics, volume resistivity, thermal conductivity, and tan δ in both temperature ranges were measured in the following manner. Table 3 shows the results.

(3) Physical properties under normal conditions: The breaking strength and hardness (JIS-A) were measured according to JIS K6301. (4) Volume resistivity: 20 mm x 100 mm from sheet
A sample of × 2 mm was cut out and measured according to SRIS2301. The smaller the volume specific resistance value, the harder the rubber is charged and the better the rubber. (5) Thermal conductivity: measured by a laser flash method. (6) tan δ: tan δ at 0 ° C. and 60 ° C. was measured at a frequency of 10 Hz using a viscoelastic spectrometer,
A relative comparison was made with the carbon powder alone blended in Comparative Example 2 being taken as 100. The larger the tan δ at 0 ° C., the better the wet skid resistance and the better the tan δ, and the smaller the tan δ at 60 ° C., the smaller the rolling resistance and the greater the fuel economy improving effect.

The additives in Table 2 are silane coupling agent: "Si69" manufactured by Dexsa, antioxidant: N-phenyl-N '-(1,3-dimethylbutyl) -P-phenylenediamine, AH -16: aroma-based oil, accelerator NS: N-tert-butyl-2-benzothiazolylsulfenamide, accelerator D: diphenylguadinine.

[0029]

[Table 2]

[0030]

[Table 3]

The following can be seen from the table.

First, in Example 1 of the present invention, Comparative Example 1 was used although an expensive silane coupling agent was not used.
(Combined use of silicon dioxide and silane coupling agent) and Comparative Example 2 (carbon powder alone) exhibit almost the same physical properties as rubber. The specific volume resistance is smaller than that of Comparative Example 2 and is excellent in antistatic performance, and the rate of temperature rise during operation is low because of high thermal conductivity. Furthermore, tan at 0 ° C.
Since δ is high, not only the wet skid resistance is significantly improved, but also tan δ at 60 ° C. is almost the same as that of Comparative Example 1, but smaller than that of Comparative Example 2, indicating remarkable low fuel consumption performance.

Example 2 shows excellent physical properties in a rubber state almost equivalent to Example 1. The volume resistivity was determined according to Comparative Example 2.
Although it is higher than that of Comparative Example 1 in which the electric resistance is a problem, it can be seen that the antistatic performance is sufficiently improved. Furthermore, the rate of temperature rise during operation is low due to the high thermal conductivity. Both the wet skid resistance and the low fuel consumption performance show almost the same good results as in the first embodiment.

In Example 3, although the amount of the silane coupling agent used was 15% of that in Comparative Example 1 and the cost was greatly reduced, the physical properties in the rubber state were the same as those in Comparative Example 1. It is almost equivalent to 2. The volume resistivity is
It is considerably smaller than Comparative Example 1 and shows extremely good antistatic performance. Further, since the thermal conductivity is high, the rate of temperature rise during operation is low. Further, both the wet skid resistance and the low fuel consumption performance show almost the same good results as in the first embodiment.

In Examples 4 and 5, the amount of the silane coupling agent used was about 31% of that in Comparative Example 1, and the rubber state properties were almost the same as Comparative Examples 1 and 2. The volume resistivity is extremely smaller than that of Comparative Example 3 (silicon carbide powder alone), indicating a very good antistatic performance, and the rate of temperature rise during operation is low due to high thermal conductivity. Furthermore, the wet skid resistance is slightly inferior to Examples 1 to 3, but is still significantly higher than Comparative Examples 1 to 3. The fuel economy performance is as good as that of the first embodiment.

In Comparative Example 3, the specific surface area was 30 m ² / g.
In this case, a smaller silicon carbide powder is used, but the breaking strength of rubber is extremely low, and it is not suitable as a reinforcing material.

[0037]

The organic polymer composition of the present invention has a good balance of antistatic, overheating, fuel efficiency and wet skid resistance without impairing the reinforcing properties. The organic polymer composition of the present invention is particularly suitable for producing a tire tread.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takushi Sakashita 1 Shinkaicho, Omuta-shi, Fukuoka F-term in the Omuta Plant of Denki Kagaku Kogyo Co., Ltd. (Reference) 4J002 AC011 AC051 AC061 AC081 AC091 BN062 BN122 BN152 CC032 CC162 CC182 CD002 CF062 CF072 CF162 CF212 CG002 CH002 CM042 CM052 CN012 CN032 CP031 CP032 DA027 DA037 DJ006 DJ017 FD016 FD017 GN01

Claims (3)

[Claims] 1. An organic polymer composition comprising a silicon carbide powder having a specific surface area of 30 m ² / g or more. 2. A mixed powder having a specific surface area of 60 m ² / g or more, containing 20 to 95% of silicon carbide powder having a specific surface area of 30 m ² / g or more and 5 to 80% of a carbon powder and / or silicon oxide powder. An organic polymer composition characterized by comprising: 3. A tire tread manufactured by using the organic polymer composition according to claim 1 or 2 as a rubber composition.