KR950004188B1 - Carbon black for tire tread rubber - Google Patents

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Description

Cavan black for tire tread rubber

1 is a schematic cross-sectional view of an example of an oil furnace used to make the carbon black of the present invention.

* Explanation of symbols for the main parts of the drawings

1: combustion chamber 2: first reaction chamber

3: second reaction chamber 4: photoreaction chamber

5A: Raw oil injection nozzle 5B: Crude oil injection nozzle

6: combustion burner 7: cooling water injection nozzle

8: air supply port

FIELD OF THE INVENTION The present invention relates to carbon black which is useful in rubber for tire treads in a loster car where high wear resistance and high resilience are required.

The rubber component constituting the tire tread of the loser car requires the provision of dynamic performance that suppresses the loss of driving energy such as high resilience and low smoke.

In order to improve the above-mentioned dynamic performance in terms of the properties of the blended carbon black, it is effective to blend the carbon black having a large particle size (that is, a small specific surface area). Nevertheless, this breed of Cavern Black results in the retraction of the most important wear properties as tire treads.

The inventors have studied in view of simultaneously giving the tire tread the dynamic performance and the abrasion resistance of mutual rate doubling.

In addition to the basic properties of carbon black, such as particle size, specific surface area, and structure, the research has elucidated and demonstrated the properties of micro-selections useful for simultaneously providing abrasion resistance and resilience to rubber. No. 59-14024, No. 63-225639 and No. Hei 1-201367 and the like proposed a new carbon black.

The present invention relates to further improvement of the above-mentioned prior art by keeping the parameters consisting of coloring power and blackness and parameters consisting of aggregate distribution and surface activity, respectively, within the scope of recognition.

Accordingly, an object of the present invention is to provide a carbon black for tire tread rubber that can simultaneously provide high wear resistance and high resilience.

Another object of the present invention is to provide a carbon black suitable for tire tread rubber of a defeated car.

The above-mentioned objects of the present invention belong to the hard-based region of nitrogen adsorption specific surface area (N ₂ SA) of 65 to 84 m ₂ / g and DBP oil absorption of 100 to 150 ml / 100 g, and the following (1), (2) and ( 3) can be achieved by carbane black for tire tread rubber that satisfies the characteristics requirements of the formula.

However, in the above formula, N ₂ SA is the nitrogen adsorption specific surface area (㎡ / g), TINT is the non-pigmentation power (%), Bn is the blackness (%), and ΔDst (nm) is the aggregate Stoke's light distribution curve. The difference between the two Stokes diameters where 50% frequency of the maximum frequency is obtained, Dst (nm) is the Stokes diameter of the maximum frequency in the distribution curve of the aggregated Stokes diameter, and IA is the amount of oxo adsorption (mg / g).

Among the characteristics of the carbon black specific to the present invention, the range of 65 to 84 m ₂ / g of nitrogen adsorption specific surface area (N ₂ SA) and 100 to 150 ml / 100 g of DBP oil absorption is equivalent to that of the carbon black of normal HAF level. In addition to this, it is a precondition for providing resilient elasticity and low smoke resistance favorable to the compounded rubber and suppressing the retraction of extreme wear resistance.

When the nitrogen adsorption specific surface area (N ₂ SA) and the DBP oil absorption amount are 65 m 2 / g or less and 100 ml / 100 g or less, respectively, it becomes impossible to impart wear resistance to tire tread. When the nitrogen adsorption specific surface area (N ₂ SA) and the DBP oil absorption amount exceed 84 m ₂ / g and 150 ml / 100 g, respectively, the repulsive elasticity decline is remarkable.

The characteristics of carbon black represented by formulas (1) and (2) are low in specific gravity per maintenance surface area and the coloring power and parameters of blackness are low, respectively, and the particulate properties represented by formula (3) are aggregated surface activity. Regardless of the above value.

In the case of satisfying the above-described prerequisites and further satisfying the selective characteristic requirements of these formulas (1) to (3), high wear resistance and high resilience can be imparted to the compounded rubber at the same time.

In order to impart high wear resistance to the rubber component, it is effective to reduce the particle size as much as possible. Usually, a nitrogen adsorption specific surface area of 84 m 2 / g or more is used. According to the present invention, wear resistance is effectively improved even if the specific gravity is in the range of 65 to 84 m < 2 > / g when the specific gravity of the formula (1) is satisfied. However, the lowering of the true specific gravity represented by the expression (1) increases the coloring power, blackness and the like, leading to a decrease in the dynamic rubber performance. This decrease in the dynamic rubber performance is suppressed by satisfying the conditions of the selected particle aggregate properties shown in the formulas (2) and (3), and conversely, in the direction of increasing the rebound elasticity.

Such a specific action expresses the effect of giving a good balance between the high wear resistance and the high rebound elasticity, which is particularly required for the tire tread rubber of the loser car.

The above characteristics of the carbon black according to the present invention are measured by the following method.

(1) Nitrogen adsorption specific surface area (N ₂ SA)

According to ASTM D3037-86 "Standard Test Method for Carbon Black-Surface Area by NitrogenAdsorption", Metod B.

The value of Industry Reference Blacks (IRB) # 5 measured by this invention is 80.3 m 2 / g.

(2) DBP oil absorption (DBP)

JIS K 6221 is in accordance with (1975) Section 6.1.2, "Test method of rubber carbon black", Method A (equivalent to ASTM D2414-82).

The prescribed amount of dry carbon black is placed in the mixing chamber of the admittometer. Dibutyl phthalate is added dropwise to the burben black with a burette. When the torque of the rotor of the mixing chamber reaches a predetermined value, the burette is automatically closed by the operation of the limit switch. The oil absorption amount is calculated by the following formula.

DBP: Oil absorption of dibutyl phthalate (ml / 100g)

V: volume of dibutyl phthalate added (ml)

W _D : Amount of dry carbon black (g)

(3) busy weight:

The carbon black sample is placed in a falling lid crucible and devolartilized for 5 minutes at a temperature of 650 ± 25 ° C. The appropriate amount of carbon black is measured with a pycnomether, deposited with a small amount of benzene, and degassed under reduced pressure until no more bubbles are formed under a vacuum of 2 to 5 mmHg. Subsequently, fill the pycnometer with benzene and hold for 30 minutes in a 25 ± 0.1 ° C hot water bath. Weigh pycnometer containing benzene and carbon black.

The true weight of carbon black is calculated by the following equation.

Where A is the mass of the picnometer,

B is the mass of pycnometer + benzene,

C is the mass of the picnometer + carbon burn black

E is the mass of pycnometer + carbon black sample + benzene, and d ²⁵ ₄ is the specific gravity of benzene.

The specific gravity of 1RB # 5 measured by this method is 1.7781.

(4) Coloring power (TINT):

JIS K 6221-82 corresponding to ASTM D3265-85, "Test Method for Rubber Carbane Black", was according to 6.1.3, and IRB # 3 was used as a control sample.

0.1000 g (± 0.0002 g) of dry carbon black is mixed with 3.75 g of zinc oxide and 2.20 ml of amine oil at 100 revolutions (25 revolutions per one time, 4 repetitions) using a Hoover grinder. The resulting paste is applied with a film spatula (0.003 inches) to the thickness specified on the glass plate. The reflectance (T) of the Cavan black dough applied to the glass plate is measured with a reflectometer (Densicron, Welch Scinetific Co., A9155, Reflector Head # 3832A) which indicates an 80% reflectivity of the standard Cavan black sample dough. The coloring power of the carbon black sample is calculated by the following formula:

Coloring power = 80 / Tx [Coloring power of standard carbon black (%)] The tint of IRB # 3 is 100%.

(5) Blackness (Bn):

0.500 g of a dry carbon black sample having a particle size of 149 µm or less is accurately weighed, and is sufficiently won while dropping linseed oil on a glass plate. The resulting dough is kneaded 25 * 5 times with a load of 151 lb on a hoover muller to form a film on the surface of the measuring glass. Place the Danshron head (Densicron, WelchSientific Co., A9155 reflecting head 3832A) on a film formed with a pre-made reference sample IRB # 2 and set it to 50%. Place the head on the sample carbon black film in this state, read the meter value, move the head 5 places and measure and treat the average value to calculate the blackness by the following equation:

Blackness = 50 / T × 100 (%)

However, T is the measured value of the sample carbon black, 100 is the blackness of IRB # 2 at reference time, 50 is the set value of the reference sample IRB # 2 film.

, △Dst :(6)

, ΔDst:

(nm)로 하고, 최대빈도의 50%의 빈도가 얻어지는 대소 2점의 스토크스 상당경의 차를 △Dst(nm)로 한다. 이 측정방법에 따른 ASTM D-24 Standard Reference Black C-3(N234)의

및 △Dst는 각 80nm 및 60nm이다.Dry the carbon black sample according to JIS K6221 (1975), 6.2.1, method A. Accurately improve the dry carbon black sample and mix it with a 20% ethanol aqueous solution containing a small amount of surfactant (dispersant) to prepare a dispersion of carbon black concentration 50 mg / 1, which is sufficiently dispersed with ultrasonic waves to prepare a sample. A disk centrifuge device (manufactured by JoyesLoeb1, UK) is set at a rotational speed of 8000 rpm, 10-20 ml of spin liquid (2% aqueous glycerin solution) is added, and 1 ml of buffer liquid (ethanol aqueous solution) is added. Finally, 0.5 ml of the sample is added with a syringe, centrifugal sedimentation is started, and the recorder is operated at the same time to create an optically equivalent aggregate stoke distribution curve. Stokes equivalent diameter of the maximum frequency in the distribution curve

It is set to (nm), and let the difference of the Stokes equivalence diameters of two small and small points which the frequency of 50% of the maximum frequency be obtained into (DELTA) Dst (nm). Of ASTM D-24 Standard Reference Black C-3 (N234)

And Dst are 80 nm and 60 nm, respectively.

(7) Oxo adsorption amount (IA)

According to JIS K6221-1982 "Test Method for Rubber Carbon Black", 6.1.1 (corresponding to ASTM D1510-81).

The carbon black of the present invention having the above-mentioned characteristics can be produced, for example, by controlling various conditions such as fuel gas flow amount and reaction residence time using an oil furnace as shown in FIG. The oil furnace comprises a combustion chamber (1) having a tangential air supply port (8) in its head and a combustion burner (6) inserted into the furnace direction, and a first reaction chamber narrowed in a tapered shape coaxially speaking. 2), the second reaction chamber 3 of continuous narrow diameter, and the photoreaction chamber 4 provided with the cooling water spray nozzle 7 are provided.

The raw material oil is injected into the narrowest part of the first reaction chamber 2. At this time, it is effective to divide the raw material oil into two parts and introduce a portion thereof in the same plane as the gas flow and a portion thereof in the same plane as the gas flow and the right angle.

The carbon black of the present invention is formulated to elastomers such as natural rubber, styrene butadiene rubber, polybutadiene rubber, isoprene rubber, butyl rubber, synthetic rubbers of various types that can be reinforced with commercially available carbon burn black according to conventional methods. You may also do it.

The blending ratio of the carbon black is 25 to 150 parts by weight based on 100 parts by weight of the rubber component, and the carbon black is mixed with the rubber composition for tire tread together with the necessary components such as a vulcanizing agent, a vulcanization accelerator, an anti-aging agent, a vulcanizing agent, a softener and a plasticizer. You may be.

Hereinafter, the Examples of the present invention will be described in more detail in comparison with Comparative Examples.

Examples 1-3 and Comparative Examples 1-4

(1) Preparation of Cavan Black:

As shown in FIG. 1, the combustion chamber 1 (50 nm in diameter and 1000 nm in length) having a tangential air supply port 8 in the head and a combustion burner 6 inserted in the furnace direction is connected coaxially with the combustion chamber. Moderately narrow first reaction chamber (2) and narrow second reaction chamber (3) (front reaction chamber: inlet diameter 250nm, narrowest diameter 180mm, taper length 1000nm, narrowest diameter length 300mm, and rear reaction chamber Diameter 200 mm, length 1000 mm) and an oil furnace having a diameter of 400 mm having a cooling water injection nozzle (7, 7) and a rear stage reaction chamber (4) having a length of 6000 mm is installed in two places. 5 A of raw oil injection nozzles axially inserted from the head part and the separate raw oil injection nozzles 5B which penetrate perpendicularly to a shaft are attached to the narrowest diameter part so that the injection position of raw material oil may be coplanar. . 5 A of raw material oil injection nozzles of the axial direction were adjusted so that injection angle might be 40-45 degrees.

As the main raw material oil, specific gravity 1.072 (15/4 ℃), toluene insoluble content 0.06%, correlation coefficient (BMCI) 141, initial boiling point 177t, Na ⁺ 1.1ppm and K ⁺ 0.4ppm aromatic hydrocarbon oil were used. Hydrocarbon oils of 1.045 (15/4 ° C.), toluene insolubles 0.02%, correlation coefficient (BMCI) 125, initial boiling point 200 ° C., Na + 4.7 ppm and K + 0.5 ppm were used.

Carban black (three types) having a characteristic range used in the present invention was prepared by applying the development conditions shown in Table 1 using the above reaction furnace, raw material oil and fuel oil.

Table 1

Note: (1), (2): Distance from the entrance of the second reaction chamber

Table 2 shows the various properties of the carbon black prepared under the conditions of Table 1.

In Table 2, the carbon blacks of Comparative Examples 1 to 4 had a nitrogen adsorption specific surface area (N ₂ SA) and a DBP oil absorption amount belonging to the hard-based region within the scope of the present invention (1), (2) or (3 It does not satisfy the requirements of) formula.

TABLE 2

(2) rubber compounding

Next, it was mix | blended with styrene-butadiene rubber (SBR) by the polymerization ratio shown in Table 3 of each carbon black of Table 2.

TABLE 3

Various rubber properties were measured for the rubber composition obtained by vulcanizing the compound of Table 3 at a temperature of 145 ° C. The results are shown in Table 4.

The exothermicity and wear of rubber properties were measured according to the following methods and conditions, and all others were measured according to JIS K63301 "General Rubber Physical Test Method".

(1) exothermic degree:

According to ASTM D623-78 (using Goodrich Flexomerter).

(2) Abrasion amount:

Measured under the following conditions using a Lambbourn abrasion tester (mechanical slip mechanism).

Test piece: thickness 10mm, outer diameter 44mm

Emery wheel: GC type, particle size 80, hardness H

Carburundum powder added: particle size 80, added amount about 9g / min

Relative slip ratio between emery wheel and specimen: 24%, 60%

Test piece rotation speed: 535rpm

Test Load: 4kg

Table 4

As is clear from the results in Table 4, in the examples of the present invention, the dynamic rubber properties such as wear resistance, rebounding properties, and smoke retardance are improved in a good balance therebetween as compared with the comparative examples of equivalent particle sizes.

As described above, the carbon black of the present invention is capable of simultaneously providing high wear resistance and dynamic performance (high rebound elasticity and low smoke resistance) to the compounded rubber through its unique particle shape. Therefore, by combining the carbane black of the present invention with the tire tread rubber of the loser car, it is possible to effectively realize a low fuel consumption of reduction of rolling resistance during traveling.

Claims (1)

For tire tread rubber, which belongs to hard area of nitrogen adsorption specific surface area 65-84m2 / g and DBP oil absorption 100-150ml / 100g, and satisfies the characteristics requirements of the following formulas (1), (2) and (3): Cavan Black:

In the above formula, N ₂ SA is the nitrogen adsorption specific surface area (㎡ / g), TINT is the non-pigmentation power (%), Bn is the blackness (%), △

(nm) is the difference between two large and small Stokes equivalent diameters at which 50% frequency of the maximum frequency in the aggregate Stokes equivalent diameter distribution by centrifugal sedimentation method is obtained, and Dst (nm) is the electric aggregate Stokes equivalent diameter distribution. The Stokes equivalent diameter of the maximum frequency of, and IA is the amount of adsorption of oxo (mg / g).

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