KR20150045169A - Rubber composition for tire containing carbon nanotube - Google Patents

Abstract

The present invention relates to a rubber composition for a tire. More specifically, the rubber composition comprises rubber, self-aligned carbon nanotube, and carbon black. According to the present invention, the self-aligned carbon nanotube is uniformly distributed on the rubber composition so that provided is a tire having excellent mechanical strength and improved viscoelasticity.

Description

Technical Field [0001] The present invention relates to a rubber composition for a tire containing carbon nanotubes,

The present invention relates to a rubber composition for a tire containing carbon nanotubes and a rubber composite material for a tire comprising the carbon nanotube.

Tires are classified according to vehicle type, structure, season, application, and pattern. In general, the components forming the tire are tread, shoulder, sidewall, and bead. Various rubber compositions suitable for the performance required for each component are applied .

Tires are required to satisfy various characteristics. In recent years, rubber compositions capable of exhibiting balanced characteristics in terms of economy, safety and abrasion resistance due to the demand for development of high-performance environmentally friendly tires are becoming important.

In general, the physical properties of the rubber composition are controlled by varying the mixing ratio of the starting rubber or by mixing the functional additives. In recent years, carbon composite materials such as carbon black, carbon nanotubes and graphene Attempts to improve are being made.

Of the above carbon-based materials, particularly carbon nanotubes are typical carbon nanostructures having excellent thermal conductivity, electrical conductivity, and mechanical strength, and are attracting attention as materials applicable to various electric devices and high-strength nanocomposites.

However, since carbon nanotubes are entangled with each other by a strong van der Waals force, they are not uniformly dispersed in a medium to be complexed. Accordingly, attempts have been made to introduce a functional group onto the surface of a carbon nanotube to modify it, or to apply a multi-step physical process. However, such a method requires a complicated pretreatment process, resulting in a deterioration in productivity. In addition to the use of an organic solvent which is harmful to the human body or the environment, deterioration of the physical properties due to damage of the carbon nanotubes occurs in the pretreatment of the carbon nanotubes And the like.

Further, when additives such as carbon-based materials are used, thermal conductivity, electrical conductivity, abrasion resistance, etc. of the tire can be improved, but it is difficult to secure viscoelasticity relatively.

The present invention is to provide a rubber composition for a tire which enables to provide a tire having a superior mechanical strength and a further improved viscoelasticity.

The present invention also provides a rubber composite for a tire comprising the composition.

According to the present invention, there is provided a rubber composition for a tire comprising rubber, a self-aligned carbon nanotube, and carbon black.

According to the present invention, the rubber composition for a tire may comprise 0.1 to 30 parts by weight of the self-aligned carbon nanotubes and 10 to 80 parts by weight of the carbon black with respect to 100 parts by weight of the rubber.

The rubber may be at least one selected from the group consisting of natural rubber, butyl rubber, halogenated butyl rubber, butadiene rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, styrene butadiene styrene rubber, styrene ethylene / butadiene styrene rubber, isoprene rubber, Butadiene rubber, isoprene rubber, isoprene rubber, chloroprene rubber, neoprene rubber, and ethylene propylene diene rubber.

The self-aligned carbon nanotubes may also include bundles of self-aligned carbon nanotubes having a diameter of 5 to 50 nm and a length of 1 to 300 μm.

On the other hand, according to the present invention, there is provided a rubber composite for a tire comprising the composition.

The rubber composition according to the present invention exhibits excellent mechanical strength and improved viscoelasticity, so that it is possible to improve the running stability and braking characteristics of the vehicle when applied to the production of tires.

1 shows a carbon nanotube in the form of a self-aligned bundle (Fig. 1 (a)) and an entangled carbon nanotube (Fig. 1 (b)) under a scanning electron microscope ). ≪ / RTI >
2 is a graph showing the results of viscoelasticity measurement for a composite material comprising a rubber composition according to one embodiment of the present invention (FIG. 2 (a)) and a comparative example (FIG. 2 (b)

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a rubber composition for a tire and a rubber composite material containing the same according to a specific embodiment of the present invention will be described in detail.

Prior to that, and unless explicitly stated throughout the present specification, the terminology is used merely to refer to a specific embodiment and is not intended to limit the present invention. And, the singular forms used herein include plural forms unless the phrases expressly have the opposite meaning. Also, as used herein, the term " comprises " embodies certain features, areas, integers, steps, operations, elements and / or components, It does not exclude the existence or addition of a group.

Meanwhile, the inventors of the present invention have conducted studies on rubber compositions for tires containing carbon nanotubes (hereinafter, referred to as 'CNT'), and self-aligned bundle-shaped carbon nanotubes are entangled, It is confirmed that the carbon nanotubes exhibit excellent dispersibility even without a separate pretreatment. Furthermore, the self-aligned carbon nanotubes can have equivalent mechanical properties even if only a small amount (for example, 1/10) of the carbon nanotubes are added to the carbon nanotubes in the tangent form, and in particular, It is confirmed that the composite material can be provided.

According to one embodiment of the present invention, there is provided a rubber composition for a tire comprising rubber, a self-aligned carbon nanotube, and carbon black.

First, according to one embodiment, the rubber may be applied to various kinds of rubber that meet the purpose of each component such as a tread of a tire, a side wall, an innerliner, and the like. As a non-limiting example, the rubber may be natural rubber, synthetic rubber, or a mixture thereof. Specifically, the rubber may be at least one selected from the group consisting of natural rubber, butyl rubber, halogenated butyl rubber, butadiene rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, styrene butadiene styrene rubber, styrene ethylene / butadiene styrene rubber, Butadiene rubber, styrene-butadiene rubber, butylene isoprene rubber, chloroprene rubber, neoprene rubber, and ethylene propylene diene rubber.

According to one embodiment, the carbon black is a carbon-based component added to improve mechanical strength such as abrasion resistance, and the kind thereof is not particularly limited. By way of non-limiting example, the carbon black may be furnace black, acetylene black, channel black, lamp black, thermal black, and the like.

The carbon black may be used in an amount of 10 to 80 parts by weight, or 20 to 80 parts by weight, or 20 to 70 parts by weight, or 25 to 60 parts by weight, or 25 to 50 parts by weight, or 30 to 50 parts by weight, 45 parts by weight. That is, it is advantageous that the carbon black is contained in an amount of 10 parts by weight or more based on 100 parts by weight of the rubber in order to sufficiently exhibit the effect of improving the mechanical strength required in the present invention. However, when the carbon black is added in an excessive amount, the dispersibility to the medium may be lowered, and the mechanical properties of the composition may be lowered. Accordingly, it is advantageous that the carbon black is contained in an amount of 80 parts by weight or less based on 100 parts by weight of the rubber.

Meanwhile, the rubber composition for a tire according to one embodiment includes self-aligned carbon nanotubes.

As shown in Fig. 1, the self-aligned CNTs (Fig. 1 (a)), unlike the CNTs of the entangled structure [Fig. 1 (b)], have diameters of several to several tens of nanometers And a plurality of self-aligned CNTs having a length of several to several hundreds of micrometers scale. Accordingly, when the self-aligned CNTs are mixed with the rubber (medium), a plurality of bundles of CNTs may be dispersed in the composition in a loosened form. However, the CNTs having entangled structures are poor in dispersibility due to the entangled shapes of CNTs or the strong van der Waals forces, while the self-aligned CNTs are subjected to a separate pretreatment (For example, a method of introducing a functional group onto the surface of a carbon nanotube) or a multistage physical dispersion method or the like, it is possible to exhibit excellent dispersibility. Accordingly, the self-aligned CNTs can achieve equal or more mechanical strength by adding a small amount (for example, 1/10) of CNTs compared to the tangled CNTs.

On the other hand, the viscoelasticity of the rubber composition has a high possibility of contradicting with the mechanical strength, and when the carbon-based material such as CNT, carbon black or the like is included in the rubber composition, it is difficult to secure viscoelasticity relatively. However, the rubber composition for a tire according to one embodiment of the present invention has the advantage of enabling the expression of viscoelasticity to be improved while ensuring mechanical strength such as abrasion resistance by including the self-aligned CNTs.

The self-aligned CNTs may be conventional ones having a plurality of CNTs arranged in a bundle shape. The structures of single walled carbon nanotubes (CNTs) and multiwalled carbon nanotubes (CNTs) It is not limited. However, according to one embodiment, the self-aligned CNT includes a plurality of carbon nanotubes having a diameter of 5 to 50 nm and a length of 1 to 300 탆, Can be more advantageous.

In this case, the self-aligned CNT may be used in an amount of 0.1 to 30 parts by weight, or 0.5 to 30 parts by weight, or 0.5 to 25 parts by weight, or 0.5 to 20 parts by weight, or 1 to 15 parts by weight, Or 1 to 10 parts by weight, or 1.5 to 5 parts by weight. That is, it is advantageous that the self-aligned CNT is contained in an amount of 0.1 part by weight or more based on 100 parts by weight of the rubber in order to sufficiently exhibit the effect of improving the physical properties required in the present invention. However, when CNT is added in excess, the CNT dispersion and mechanical properties of the composition may be deteriorated. Accordingly, it is advantageous that the self-aligned CNT is included in an amount of 30 parts by weight or less based on 100 parts by weight of the rubber.

Meanwhile, according to one embodiment, the rubber composition for a tire may further include an emulsifying agent. The emulsifier improves the dispersibility and processability of the carbon black and the CNT to the raw material rubber, thereby making it possible to provide a rubber composition having a more uniform composition. As the above-mentioned emulsifier, a usual one can be used, and the kind thereof is not particularly limited. However, as a non-limiting example, the emulsifier may be at least one compound selected from the group consisting of paraffinic oils, aromatics oils, solid waxes and vegetable emulsifiers among the synthetic emulsifiers. The amount of the emulsifier is preferably 1 to 20 parts by weight based on 100 parts by weight of the rubber, because excessive addition of the emulsifier may cause deterioration of the physical properties of the composition.

According to another embodiment of the present invention, there is provided a CNT-rubber composite for a tire comprising the above-mentioned rubber composition.

The CNT-rubber composite material for a tire is a composite material in which carbon black and CNTs are uniformly dispersed in a matrix containing a raw material rubber. Especially, since the CNT-rubber composite material is formed using a rubber composition containing self-aligned CNTs, Excellent and viscoelastic properties can be exhibited.

Such a rubber composite material can be applied to various components such as tread, side wall, innerliner, etc. of a tire. Especially, it is applied to a tread of a tire to improve the running stability of the vehicle and the braking characteristic .

Best Mode for Carrying Out the Invention Hereinafter, preferred embodiments are described to facilitate understanding of the present invention. However, the following examples are intended to illustrate the present invention without limiting it thereto.

Example  One

1 part by weight of self-aligned multi-wall CNT (manufactured by Hanwha Chemical Co., Ltd., product name: CM-150, bundle diameter of about 20 占 퐉) per 100 parts by weight of raw rubber (containing 70% by weight of natural rubber and 30% by weight of chlorobutyl rubber) , 30 parts by weight of carbon black (manufacturer: Korea Carbon Black, product name: N220) and 11 parts by weight of an emulsifier (component name: Castor oil) were mixed in a kneader and then subjected to 2-roll milling and hot pressing To obtain a rubber composite.

Example  2

A rubber composite was obtained in the same manner as in Example 1, except that 3 parts by weight of self-aligned multi-wall CNT was added to 100 parts by weight of the raw rubber.

Example  3

A rubber composite was obtained in the same manner as in Example 1, except that 5 parts by weight of self-aligned multi-wall CNT was added to 100 parts by weight of the raw rubber.

Comparative Example  One

Example 1 was repeated except that 1 part by weight of CNT (manufactured by Hanwha Chemical Co., Ltd., product name: CM-95) having an entangled structure was added to 100 parts by weight of the raw rubber in place of the self- A rubber composite was obtained in the same manner.

Comparative Example  2

Except that 3 parts by weight of CNT (manufactured by Hanwha Chemical Co., Ltd., product name: CM-95) having an entangled structure instead of the self-aligned multi-wall CNT was added to 100 parts by weight of the starting rubber. A rubber composite was obtained in the same manner.

Comparative Example  3

Except that 5 parts by weight of CNT (manufactured by Hanwha Chemical Co., Ltd., product name: CM-95) having an entangled structure instead of the self-aligned multi-wall CNT was added to 100 parts by weight of the raw rubber. A rubber composite was obtained in the same manner.

Comparative Example  4

A rubber composite was obtained in the same manner as in Example 1, except that 30 parts by weight of carbon black (manufacturer: Korea Carbon Black, product name: N220) was added without adding the self-aligned multi-wall CNT.

Comparative Example  5

A rubber composite was obtained in the same manner as in Example 1, except that the self-aligned multi-wall CNT was not added and the content of the carbon black was adjusted to 31 parts by weight.

Comparative Example  6

A rubber composite was obtained in the same manner as in Example 1, except that the self-aligned multi-wall CNT was not added and the content of the carbon black was adjusted to 33 parts by weight.

Test Example  1 (electric conductivity index measurement)

The electrical conductivity index (relative value) of each of the rubber composites according to Example 2 and Comparative Example 2 was measured by a 4-point probe measurement method (JIS K 7194).

As a result, based on the rubber composite of Comparative Example 2 (electrical conductivity index 100), the rubber composite of Example 2 was measured to have a cell conductivity index of 197. That is, the rubber composite of Example 2 contained the same amount of CNT as the rubber composite of Comparative Example 2, but it was confirmed to have a relatively high electrical conductivity index.

Test Example  2 ( Viscoelastic  Measure)

The viscoelasticity (tan?) Of the rubber composites according to Examples 1 to 3 and Comparative Examples 1 to 6 was measured using a viscoelasticity analyzer (DMA, model name: Q800, manufacturer: TA Instruments) 2.

Composite material tanδ Composite material tanδ Composite material tanδ Example 1 0.289 Comparative Example 1 0.217 Comparative Example 4 0.224 Example 2 0.366 Comparative Example 2 0.225 Comparative Example 5 0.246 Example 3 0.449 Comparative Example 3 0.228 Comparative Example 6 0.277

As can be seen from Table 1 and FIG. 2, Comparative Examples 5 and 6, in which the content of carbon black was increased without CNT, gently increased in viscoelasticity, and the content of entangled-CNT was increased To 3 were found to be less viscoelastic than Comparative Examples 5 and 6.

On the other hand, the composites of Examples 1 to 3 including aligned-CNT exhibited sharply increasing viscoelasticity as compared with Comparative Examples 4 to 6, and had significantly improved viscoelasticity as compared with Comparative Examples 1 to 3 containing the same amount of CNT .

Test Example  3 ( Modulus  Measure)

Five test specimens of type I according to ASTM D638 were prepared from the rubber composites according to Examples 1 to 3 and Comparative Examples 1 to 6, and Young's Modulus was measured using a universal testing machine. The results are shown in Table 2 below Respectively.

Composite material Young's Modulus (N) Composite material Young's Modulus (N) Composite material Young's Modulus (N) Example 1 61 Comparative Example 1 55 Comparative Example 4 50 Example 2 74 Comparative Example 2 67 Comparative Example 5 51 Example 3 84 Comparative Example 3 77 Comparative Example 6 58

As can be seen from the above Table 2, the composites of Examples 1 to 3 were found to exhibit significantly improved modulus as compared to the composites of the comparative examples comprising the same amount of carbon-based additives.

Claims (5)

A rubber composition for a tire, comprising a rubber, a self-aligned carbon nanotube, and carbon black.
The method according to claim 1,
With respect to 100 parts by weight of the rubber,
0.1 to 30 parts by weight of the self-aligned carbon nanotubes, and
10 to 80 parts by weight of the carbon black
And a rubber composition for a tire.
The method according to claim 1,
The rubber may be at least one selected from the group consisting of natural rubber, butyl rubber, halogenated butyl rubber, butadiene rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, styrene butadiene styrene rubber, styrene ethylene / butadiene styrene rubber, isoprene rubber, A rubber composition for a tire, which is at least one rubber selected from the group consisting of rubber, chloroprene rubber, neoprene rubber, and ethylene propylene diene rubber.
The method according to claim 1,
Wherein the self-aligned carbon nanotube comprises a bundle of self-aligned carbon nanotubes having a diameter of 5 to 50 nm and a length of 1 to 300 m.
A rubber composite for a tire comprising the rubber composition according to claim 1.

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