KR20120090585A

KR20120090585A - Electro conductive inner liner rubber composition

Info

Publication number: KR20120090585A
Application number: KR1020110011096A
Authority: KR
Inventors: 장윤기
Original assignee: 금호타이어 주식회사
Priority date: 2011-02-08
Filing date: 2011-02-08
Publication date: 2012-08-17

Abstract

PURPOSE: An innerliner rubber composition is provided to effectively disperse static electricity stored inside, and to improve electric conductivity by using specific two kinds of conductive carbon material as a reinforcing agent. CONSTITUTION: An innerliner rubber composition comprises 1-10 parts by weight of carbon black and graphite, and 100.0 parts by weight of crude rubber. DBP of the carbon black is 450-550 ml/100g, BET is 1250-1300 m^2/l, and apparent density is 100-130 g/l. Density of the graphite is 0.5-0.7 g/cm^3, DBP is 45-55 g/100g, and BET is 3.95-4.05 m^2/g. The cure rubber is a mixed rubber of a natural rubber and a butadiene rubber. The weight ratio of the carbon and the graphite is 1-9:9-1.

Description

Anti-static inner liner rubber composition {ELECTRO CONDUCTIVE INNER LINER RUBBER COMPOSITION}

The present invention relates to an anti-static inner liner rubber composition, and more particularly, it comprises two kinds of conductive carbon materials which can impart both conductivity and reinforcement as reinforcing fillers to the raw material rubber. An improved antistatic innerliner rubber composition is disclosed.

Recently, as the production of tires in consideration of stability and eco-friendly aspects such as traction and low fuel consumption characteristics on wet roads has increased, the application rate of silica in tire production has increased rapidly.However, in the case of tires applied with silica, the molecular structure and The coupling property in the tire compound structure causes a problem that static electricity is generated inside the tire.

In other words, unlike carbon black having a plate-like or more complicated structure, silica has a structure in which electrons cannot be moved, and thus, as the amount of silica used increases, electrical conductivity significantly decreases.

In the related art, a method of treating an electrically conductive metal powder on the surface of a tread or a compound of a tire, and a method of arranging a compound including conductive carbon black in a predetermined direction of a tire tread have been introduced. Because of the blending problem, there have been many difficulties in applying it to mass production.

In the Republic of Korea Patent Publication No. 2002-0040197, in order to solve the electrostatic generation problem, the carbon black, such as Daegusa-Hulse's XE-2 black product with excellent electrical conductivity, was applied to maximize the electrical conductivity in the compound for treads. In the case of using carbon black, the electrical conductivity increases to some extent as the amount of carbon black is increased. However, when carbon black is included in an excessive amount, the physical properties of the carbon black become difficult to bond the carbon black with other polymers or drugs. There is a problem that the electrical resistance is increased again.

In addition, Japanese Patent Application Laid-Open No. 11-296766 intends to improve electrical conductivity by placing a thread such as filament that exhibits electrical conductivity inside the tread in a cloud direction, because wear progresses faster than a rubber compound due to the characteristics of the fiber. In addition, when the tire is subjected to friction in the rolling direction, the surface of the tire tread can be greatly damaged by the small holes formed by the more worn filaments.

Japanese Laid-Open Patent Publication No. 2005-002206 describes that the application of high conductive carbon black to a tread reduces the rise of electrical conductivity and rotational resistance, but in the comparative examples and examples, the high conductive carbon black (ex. EC-600JD) of 10 phr or more is compared. The best effect occurred when using. However, the application of more than 10 phr of this highly conductive carbon black significantly increases the hardness of the semi-tread product, which makes it very difficult to mold the product and increases the possibility of problems such as flat spots after molding. The disadvantage was that it became very difficult.

SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide an antistatic inner liner rubber composition having improved electrical conductivity by using two kinds of conductive carbon materials which can impart both conductivity and reinforcement as reinforcing fillers. will be.

The antistatic inner liner rubber composition of the present invention comprises 1 to 10 parts by weight of two specific conductive carbon materials with respect to 100 parts by weight of the raw material rubber.

The raw material rubber used in the present invention is not particularly limited in its kind, and may be used natural rubber, synthetic rubber or mixed rubber of natural rubber and synthetic rubber, preferably styrene butadiene rubber among natural rubber and synthetic rubber, or Butadiene rubber can be mixed and used. In this case, the mixing ratio of natural rubber and synthetic rubber is preferably 1 to 3: 7 to 9, but when the amount of natural rubber used exceeds the above range, more static electricity is generated due to the structural characteristics of natural rubber. Not desirable

The two conductive carbon materials used in the present invention are DBP 450 ~ 550ml / 100g, BET 1250 ~ 1300m ² / l, carbon black having an apparent density of 100 ~ 130g / l, density 0.5 ~ 0.7g / cm ³ , DBP 45 ~ 55g / 100g, BET 3.95 ~ 4.05m ² / g graphite.

When the physical properties of the carbon black used in the present invention are out of the above range, the hardness of the composition increases sharply when mixed with rubber, making it difficult to apply the product, or due to the undeveloped structure, there is no reinforcing effect. .

When the physical properties of the graphite used in the present invention is out of the above range, the structure is excessively developed, so there is a lot of space between the rubber and the graphite, so that the physical properties may be weakened, or the structure is not developed, so that the excessive amount of graphite to improve the physical properties There is a disadvantage that it is necessary to increase the production cost of the rubber composition is not preferred.

The two kinds of conductive carbon materials are preferably used in an amount of 1 to 10 parts by weight based on 100 parts by weight of the raw material rubber. When less than 1 part by weight, the polymer traps the carbon materials so that they hardly affect the physical properties. In case of exceeding 10 parts by weight, the structure of the carbon materials prevents the polymer from serving as a compound linkage, weakens the physical properties, increases the wear amount, and causes a sudden change in the vulcanization time. Problems arise with fairness.

There is no restriction | limiting in particular in the mixing ratio of the said 2 types of conductive carbon materials, It is preferable that it is 1-9: 9-1 in the weight ratio of carbon black: graphite.

To the rubber composition of the present invention, additives for conventional rubber compositions, for example, calcium carbonate, stearic acid, process oils, adhesives, process aids, preservatives, vulcanizing agents, activators, accelerators, etc. may be appropriately selected and added. The selection and use of these additives are known in the art.

The antistatic inner liner rubber composition of the present invention can effectively dissipate static electricity stored therein by using two kinds of specific conductive carbon materials together as reinforcing fillers, thereby improving electrical conductivity.

Hereinafter, the present invention will be described in more detail with reference to the following Examples and Comparative Examples. The following examples are merely examples for carrying out the present invention, and are not intended to limit the protection scope of the present invention.

Examples and Comparative Examples

Innerliner rubber specimens were prepared by combining the components according to the compositions shown in Table 1 below.

(Unit: weight part) division Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Natural rubber 31 31 31 31 31 Butadiene rubber 69 69 69 69 69 BTR ¹⁾ 20 20 20 20 20 Calcium carbonate ²⁾ One One One One One Activator # 1 ³⁾ 2 2 2 2 2 Process oil ⁴⁾ 9 9 9 ← 9 9 Adhesive ⁵⁾ 5 5 5 5 5 Process Preparation ⁶⁾ 5 5 5 5 5 Carbon black ⁷⁾ 65 58 58 58 58 Preservative ⁸⁾ One One One One One Vulcanizing agent ⁹⁾ 0.5 0.5 0.5 0.5 0.5 Surfactant # ²¹⁰⁾ 3 3 3 3 3 Accelerator ¹¹⁾ 1.5 1.5 1.5 1.5 1.5 Carbon Material 1 ¹²⁾ 0 7 One 3 5 Carbon Material 2 ¹³⁾ 0 0 6 4 2

week)

1) BTR: Butyl tube (type) recycled rubber (volume extender)

2) Calcium Carbonate (CaCO ₃ ): Volume Extender

3) Activator # 1: stearic acid

4) Process oil: LPCA oil

5) Adhesive: octyl-phenol formaldehyde resin

6) Process aid: aromatic naphthene aliphatic hydrocarbon resin

7) Carbon Black: Particle Size 65nm, BET 33m ² / g

8) Roasters: P-cresol and dicyclopentadiene

9) Vulcanizer: Sulfur

10) Activator # 2: Zinc Oxide

11) Accelerator: 2,2-dibenzothiazyldisulfide

12) Carbon material 1: carbon black with DBP 500ml / 100g, BET 1275m ² / l, apparent density 120g / l

13) Carbon Material 2: Graphite with Density 0.6g / cm ³ , DBP 50g / 100g, BET 4.00m ² / g

The physical properties of the rubber compositions obtained according to the above Examples and Comparative Examples were measured according to ASTM standards, and the results are shown in Table 2 below.

The electrical conductivity of the antistatic rubber specimen was preferably 10 ⁸ Ωcm or less, and the electrical conductivity was measured using a Keithley 6517 tester, and measured under an appropriate pressure without surface treatment of the sample (diameter: 30 mm, thickness: 2.1 mm, voltage range). 10 to 100 V).

division Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 100 degrees Celsius 49.7 53.2 46.4 47.7 49.9 The tensile strength
(kgf / cm2)

Hardness 56 59 53 55 57 M-300% 50.2 53.2 48.2 49.8 51.3 The tensile strength 89.3 95.4 83.3 87.9 91.7 Elongation 596.8 574.3 583.2 580.7 578.1 Fatigue

Cycle 99999 99999 99999 99999 99999 Raw 3.68 3.97 3.88 3.97 3.98 Column 4.10 4.8 4.4 4.7 4.8 Gas permeability
(cc / m ^2? atm.day) a 584.9 598.2 590.3 594.2 598.7 Electric resistance (Ω) 1.3 × 10 ¹⁴ 6 × 10 ⁸ 1.1 × 10 ¹² 9 × 10 ¹¹ 8 × 10 ⁹

As can be seen from the results of Table 2, in the case of Comparative Example 2 in which only carbon black was added except for graphite, the hardness and tensile strength of the innerliner rubber specimens were increased, and the elongation was decreased to decrease the flexural resistance. , It can be seen that there is a sufficient effect to effectively discharge the generated static electricity by reducing the electrical resistance by 10 ⁶ than Comparative Example 1. However, the hardness increases, so that the risks of cold cracking and flat spots are significantly increased, and when blending, compounding tends to deteriorate.

On the other hand, in the case of Examples 1 to 3, as a result of combining the graphite and carbon black having the physical properties according to the present invention, the rubber using only carbon black by lowering the hardness, maintaining the electrostatic discharge effect while maintaining other physical properties It was found that the composition could be complemented. These results indicate that graphite mixed with carbon black has a layered structure, which is effective in lowering hardness when mixing with rubber, and has excellent electrical conductivity. It also showed that it was very helpful in solving the problems mentioned in.

As such, the present invention provides an innerliner rubber composition that exhibits excellent performance in all aspects by mixing materials that can compensate for this, compared to the prior art only to increase the electrical conductivity while ignoring the adverse effect of the physical properties of the rubber mixture. Can provide.

Claims

100 parts by weight of raw rubber, DBP 450 ~ 550ml / 100g, BET 1250 ~ 1300m ² / l, carbon black with apparent density 100 ~ 130g / l, density 0.5 ~ 0.7g / cm ³ , DBP 45 ~ 55g / 100g , BET 3.95 ~ 4.05m ² / g graphite in an antistatic inner liner rubber composition comprising a total amount of 1 to 10 parts by weight.

The antistatic inner liner rubber composition according to claim 1, wherein the raw material rubber is a mixed rubber of natural rubber and butadiene rubber.

The antistatic inner liner rubber composition according to claim 1, wherein the mixing ratio of the carbon black and the graphite is 1 to 9: 9 to 1 by weight.