KR101977094B1 - Conductive tire composition - Google Patents

Abstract

The present invention relates to a tire composition which improves electrical conductivity while maintaining the characteristics of a conventional tire by including two or more types of carbon black among silanized silica and a carbon substrate reinforcing material capable of improving electrical conductivity as the reinforcing material of an emulsion polymerization rubber. Therefore, it is possible to provide a tire manufactured to have electrical conductivity. The present invention provides the tire composition capable of real-time measurement of a wear condition, humidity, ground contact pressure, road surface condition, earthquake vibration and the like.

Description

[0001] CONDUCTIVE TIRE COMPOSITION [0002]

TECHNICAL FIELD The present invention relates to a tire, and more particularly, to a conductive tire.

The tire is made of a tread that surrounds the outer periphery of the wheel and the wheel. The tread is filled with air to directly support the load of the vehicle, the road surface shock mitigation, the driving and control of the vehicle, Thus, the tread is the only part of the vehicle that is in direct contact with the ground, and its wear, road surface, and the like are important control information that affects vehicle stability.

However, since the tire tread is generally made of a material having a low electrical conductivity of about 10 ¹² Ω to dissipate the static electricity, it is not easy to measure the deformation of the tread, the road humidity, the ground pressure, . So, in case of abrasion or contact pressure, it is usually measured by using the test equipment at a standstill. However, such a measuring device is not a real-time measuring device, and there is no commercialized case in which a large pressure is repeatedly applied when a sensor, which is a sensitive device, is embedded in a tread. In addition, direct measurement of road surface bending state and road humidity measurement are practically difficult only by mounting a separate test equipment on a tire according to the prior art disclosed to date, real-time measurement of the road surface state is dependent on costly optical equipment, Optical instruments are not widely commercialized except for specific purposes because of the complicated function of warning of road surface due to image analysis.

In the related art, a tire having a grounding pressure measuring sensor disclosed in Korean Patent Registration No. 1343923 as a related art disclosed in order to realize real-time measurement of tread deformity is known. Since the measurement sensor portions 2 arranged in a ring shape along the circumferential direction of the tire and measuring the grounding state of the tire are provided, the grounding pressure of the tire under travel is measured, and the force in the vertical direction acting inside the tire, To a tire having a ground pressure measuring sensor capable of measuring a force. According to the above-described prior art, the loads acting on the respective portions of the tire can be measured and utilized as wear prevention materials and tire design data, and the load changes of the tires are monitored in real time during excessive cornering or vehicle braking during operation. There is an advantage that can help. However, in the above-mentioned prior art, since the measurement sensor is embedded in the tread, it is difficult to measure the ground pressure on the whole, and as described above, the pressure sensor, which is a sensitive device, can fail due to repetitive vehicle load, The pressure sensor can not be replaced or repaired, and there is a problem that the cost of the sensor itself and the cost and time required for installing the sensor are increased because a separate sensor must be installed.

In order to improve the electrical conductivity of the tire tread in order to measure the road surface state, tread deformity, and the like from the tire itself, metal powder is contained in the tire composition, or a conductive filler such as carbon nanotube, graphene, Is uniformly applied to the elastomer matrix. However, the technical difficulties and application effects are not satisfied. For example, when the conductive filler as described above is introduced, the physical strength and the electric conductivity are unbalanced. According to Korea Patent Registration No. 0523250, when the acetylene black is applied, the electric conductivity property is expected to be improved when the amount is 20 parts by weight or less But also may cause reduction of abrasion resistance and physical properties. In the case of inserting conductive metal rings (U.S. Patent No. 7029544) or inserting conductive stitches (U.S. Patent No. 6289958), only a portion of the tread has a low resistance.

Although a tire composition including a mixture of silica and carbon black has been proposed, there is no example in which electric conductivity is improved while maintaining conventional tire properties such as abrasion resistance, frictional force and the like. Therefore, it is possible to maintain the characteristics of the conventional tire even when the electric conductivity is high so that the tread wear condition, the ground pressure, the road humidity, the road surface condition, etc. can be observed in the tire itself even if the expensive and non-replaceable pressure sensor is not used separately. .

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art, and one of the various objects of the present invention is to provide a tire composition which comprises silane-silica as a reinforcing material for emulsion polymerization rubber and carbon- There is provided a tire composition comprising two or more kinds of carbon black to improve electric conductivity while maintaining the characteristics of a conventional tire, and to provide a tire having the electric conductivity manufactured by the method. In addition, one of the various objects of the present invention is to provide a tire composition capable of real-time measurement of wear, humidity, ground pressure, road surface condition, earthquake vibration, and the like in real time.

In order to solve the above problems, the tire composition according to the present invention essentially contains the following components, especially two or more kinds of carbon black, so that it has a high electric conductivity while maintaining the characteristics of a conventional tire.

(1) a rubber blend comprising a synthetic rubber selected from cis-1,4-polybutadiene rubber and styrene-butadiene rubber and natural rubber in a ratio of 1: 1 to 9: 1;

(2) 10 to 35 parts by weight of first carbon black based on 100 parts by weight of the total rubber component; And

(3) 5 to 15 parts by weight of a second carbon black, based on 100 parts by weight of the total rubber component, wherein the second carbon black has a BET surface area of 35 to 45 m < 2 > / g.

One of the various effects according to the present invention is that the conductive tire composition has very high electrical conductivity and has all the characteristics of a conventional tire.

1 illustrates an exemplary conductive tire according to an embodiment of the present invention.
Fig. 2 shows the volume resistivity and the rate of change of wear volume according to the kind of the rubber blend. The dotted line section indicates the desired section.
3 shows the volume resistivity and the change rate of the wear volume when the content of the second carbon black, the third carbon black, and the silica are the same and the content of the first carbon black is changed.

Various embodiments and / or aspects are now described with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects. However, it will also be appreciated by those of ordinary skill in the art that such aspect (s) may be practiced without these specific details. The following description and the annexed drawings set forth in detail certain illustrative aspects of one or more aspects. It is to be understood, however, that such aspects are illustrative and that some of the various ways of practicing various aspects of the principles of various aspects may be utilized, and that the description set forth is intended to include all such aspects and their equivalents.

In addition, the term " or " is intended to mean " exclusive or " That is, it is intended to mean one of the natural inclusive substitutions " X uses A or B ", unless otherwise specified or unclear in context. That is, X uses A; X uses B; Or when X uses both A and B, " X uses A or B " can be applied to either of these cases. It should also be understood that the term " and / or " as used herein refers to and includes all possible combinations of one or more of the listed related items.

It is also to be understood that the term " comprises " and / or " comprising " means that the feature and / or component is present, but does not exclude the presence or addition of one or more other features, components and / It should be understood that it does not. Also, unless the context clearly dictates otherwise or to the contrary, the singular forms in this specification and claims should generally be construed to mean " one or more. &Quot;

Some embodiments of the present disclosure relate to a tire composition wherein the tire tread is formed of a conductive material and capable of measuring in real time conditions such as wear, humidity, ground pressure, road surface condition, and earthquake vibration without the need for a separate pressure sensor.

The conductive tire composition according to the present invention may further have the following effects in terms of the electrical conductivity.

First, tread deformity, road humidity, ground pressure, and road surface condition can be measured without a separate pressure sensor or other sensor device. For example, as shown in FIG. 1, tires A and B made of an electrically conductive tire composition according to the present invention can grasp the road surface state electrically in real time.

Second, since no separate sensor is required, there is no need for a failure or maintenance of the sensor even if the tire continuously receives a large pressure during operation of the vehicle.

Third, since the tread itself constituting the outer surface of the tire acts as a sensor, the sensor action of the tread is maintained until the life of the tire is exhausted, unlike the conventional tire which can not maintain or replace the sensor even if the sensor fails.

Fourth, since the tread itself constituting the outer surface of the tire acts as a sensor, the ground pressure can be directly measured and the entire surface can be measured.

<Rubber blend>

The rubber blend used in the tire composition according to the present invention is a mixture of 10 to 90 parts by weight of natural rubber (NR) and 10 to 90 parts by weight of synthetic rubber. In the first embodiment, the synthetic rubber used in the present invention is cis-1,4-polybutadiene (BR). The cis-cis content of the cis-1,4-polybutadiene is 90 to 100% by weight, preferably 97 to 100% by weight. When the sheath content is less than 90% by weight, the desired abrasion resistance may not be obtained, and when the sheath content is less than 70% by weight, compatibility with the natural rubber (NR) may be poor and desired characteristics may not be obtained . When the natural rubber content is as low as about 0.1 to 10 parts by weight based on 100 parts by weight of the total components blended in the cis-1,4-polybutadiene rubber, there is a conflicting phenomenon as the tensile properties are lowered, So it is not desirable.

In the second embodiment, the synthetic rubber used in the present invention is styrene-butadiene rubber (SBR).

The ratio of natural rubber (NR) to synthetic rubber (BR or SBR) is from 9: 1 to 1: 9, preferably from 1: 1 to 1: 9, most preferably 1: 9. As shown in FIG. 2, when the ratio of the natural rubber to the synthetic rubber exceeds 9: 1, the volume resistivity decreases but the wear volume increases sharply, which is undesirable. When the ratio of the natural rubber to the synthetic rubber is less than 1: 9, the abrasion volume increases sharply, which is not preferable. Therefore, in order to achieve the object of the present invention, the ratio of the natural rubber to the synthetic rubber has a volume resistivity of 65 Ω.cm or less, preferably 51 Ω.cm or less and a wear volume of 125 mm ³ or less, preferably 120 mm ³ or less 1 to 1: 9, preferably 1: 1 to 1: 9, and most preferably 1: 9, which is the range in which the conventional viscoelastic characteristics can be ensured.

The chemical structures of conventional styrene-butadiene rubber (SBR), cis-1,4-polybutadiene rubber (BR) and natural rubber (NR) are as follows.

<Reinforcement material>

The tire composition according to the present invention comprises about 20 to 80 parts by weight of a reinforcing material based on 100 parts by weight of the total components. The reinforcement may include silane-silica and carbon-based fillers such as graphene oxide, carbon black, carbon nanotubes, and these components exhibit a synergistic effect with each other.

1. Silica

The reinforcing material included in the first embodiment is silica. The silica may be included in an amount of 5 to 15 parts by weight, preferably 5 to 10 parts by weight, based on 100 parts by weight of the total rubber component. If the amount is less than 5 parts by weight, the effect of reducing the rotational resistance due to the addition of silica is insufficient, and if it exceeds 15 parts by weight, the effect of improving the electrical conductivity by the carbon black used in the present invention is hindered. It is preferable that the silica has a value of about 150 to 200 m 2 / g, preferably 164 m 2 / g when measured by Brunner, Emmett, Teller surface area (hereinafter "BET surface area") using nitrogen gas. The BET surface area herein means the total surface area, including the porosity of the reinforcing material. The silica is preferably precipitated silica. The silica has a pH of from 0 to 13, preferably 11.2, and contains about 3 to 12 parts by weight, preferably 3 to 6 parts by weight, of a silane coupling agent based on 100 parts by weight of the total composition. Since the BET value and the like are the main factors that determine the characteristics of silica, if the BET value of silica etc. deviates from the specified range, the processability is deteriorated, which is not preferable.

2. Carbon-based filler

end. Carbon black

As additional reinforcing materials included in the first embodiment, there are two or more types of carbon black. The first carbon black may comprise 10 to 35 parts by weight, preferably 15 to 30 parts by weight, most preferably 20 to 25 parts by weight, based on 100 parts by weight of the total rubber component, with a BET surface area of about 1270 m 2 / g have. As shown in FIG. 3, when the content of the first carbon black is less than 10 parts by weight based on 100 parts by weight of the total rubber component, both the volume resistivity and the wear volume increase sharply, which is not preferable. If the content of the first carbon black is more than 35 parts by weight based on 100 parts by weight of the total rubber component, the volume resistivity rapidly increases, which is not preferable. Therefore, in order to achieve the object of the present invention, it is preferable that the content of the first carbon black is 10 to 35 parts by weight, preferably 15 to 30 parts by weight, most preferably 20 to 30 parts by weight, which is a section where both the volume resistivity and the wear- 25 parts by weight.

The first carbon black has a DBP (value indicating the structure of the reinforcing filler) of 480 to 510 mL / 100 g, preferably 498 mL / 100 g.

The second carbon black has a BET surface area of 35 to 45 m 2 / g, preferably 35 to 40 m 2 / g, and is contained in an amount of 5 to 15 parts by weight, preferably 5 to 10 parts by weight, based on 100 parts by weight of the total rubber component . The second carbon black has an I2 moisture absorption amount (iodine absorption amount representing the surface area of the reinforcing material) of about 37 to 47 g / kg, preferably 42.5 g / kg when measured according to ASTM D1510. The second carbon black has a statistical surface area (STSA) of 38.7 m 2 / g with a pH of 6 to 10, preferably 7.3, as measured according to ASTM D6556. Since the DBP value and the I2 absorption amount are main factors determining the physical properties and chemical properties of the carbon black, it is difficult to expect the improvement of the electric conductivity when the DBP value of the carbon black and the I2 absorption amount and the addition amount are out of the above range.

The first embodiment may further comprise a third carbon black having a BET surface area of 100 to 121 m &lt; 2 &gt; / g. The third carbon black has an I2 moisture absorption of about 116 to 126 g / kg, preferably 123.3 g / kg, as measured according to ASTM D1510. The pH of the third carbon black is about 6 to 10, preferably about 8. When the third carbon black is included, the first carbon black may be included in an amount of 20 to 25 parts by weight based on 100 parts by weight of the total rubber component, and the second and third carbon black may be included in an amount of about 5 to 10 parts by weight . The third carbon black may be included in place of the second carbon black. If the total amount of carbon black does not fall within the above-mentioned range, it is not preferable because it is difficult to expect an improvement in electric conductivity. If the total amount exceeds the specified range, the reinforcing property of the tire tread is lowered.

I. Carbon nanotube

The tire composition according to the present invention may contain 0.1 to 1 part by weight of carbon nanotubes based on 100 parts by weight of the total rubber component. The carbon nanotubes are preferably multi-walled carbon nanotubes (MWCNTs) having a BET surface area of about 220 m 2 / g, a diameter of about 140 nm, a length of about 7 μm, and a density of about 1.7 mL at 25 ° C.

All. Graphene oxide

The tire composition according to the present invention may contain graphene oxide in an amount of 0.1 to 1 part by weight based on 100 parts by weight of the total rubber component, together with carbon nanotubes or carbon nanotubes. The graphene oxide is preferably reduced graphene oxide (RGO) having a BET surface area of at least about 450 m &lt; 2 &gt; / g.

There may be embodiments in which the reinforcement material is the same as the reinforcement material included in the first embodiment described above but the rubber blend component or blend ratio is different.

<Additives>

The tire composition according to the present invention may further comprise conventional additives known in the rubber / tire industry. Examples of such additives include, but are not limited to, sulfur vulcanizing agents, accelerators, activators, antioxidants, waxes, process oils, and the like. These additive (s) are included in amounts known per se in the rubber / tire industry and are known in the art. For example, the tire composition according to the present invention has an aromatic oil having a density of 0.9530 at 15 DEG C (based on ASTM D4052) and a viscosity of 19.29 (based on ASTM D445) at 100 DEG C, in an amount of 5 to 15 parts by weight, Preferably 5 to 10 parts by weight.

<Manufacturing Method>

In order to prepare the tire composition according to the present invention, the rubber blend, the carbon-based filler, the process oil, the antioxidant, etc. described above are mixed at an elevated temperature of about 90 to 150 캜, preferably 90 to 100 캜. And then mixed with activators, accelerators, and vulcanizing agents at a low temperature of about 25 to 50 DEG C to prevent the resulting mixture from being vulcanized at too early steps. The mixed composition is then sheet-out and vulcanized at a rheometer at about 100 to 190 占 폚, preferably 120 to 160 占 폚. The optimal vulcanization characteristics can be modified so that the resulting sample has desirable standard properties.

In order to obtain a homogeneous mixture, it is desirable to subject the rubber component and other components to a two-roll mill for a controlled period of time. In the present invention, the time to pass through the double-roll mill is suitably 5 to 20 minutes, preferably 10 to 15 minutes. The temperature in the double-roll mill is determined according to the properties of the desired composition, but usually 25 to 120 ° C is suitable, and 25 to 50 ° C is preferred.

<Examples>

The following examples are intended to illustrate the present invention only, and the scope of protection of the present invention is not limited by these examples. The abbreviations described in the following Comparative Examples and Examples mean the following.

NR: natural rubber;

BR: cis-1,4-polybutadiene rubber

SBR: styrene-butadiene rubber;

TMTD: Tetramethyl thiuram disulfide;

CZ: N-cyclohexyl-2-benzothiazole sulfonamide;

SA, S / T: stearic acid;

6PPD: 1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine;

TMQ: 2,2,4-trimethyl-1,2-dihydroquinoline polymer;

TDAE: Treated Distillate Aromatic Extract

1. Comparative Example

As shown in the table below, unlike the present invention, a tire composition containing only one carbon black and no silica, carbon nanotubes, and graphene was prepared with various ratios of NR / BR and NR / SBR.

As a result, weak interfacial interaction occurred between the carbon black and the rubber blend in the tire composition, resulting in poor strength and abrasion resistance characteristics. As a result, all of the above comparative examples (C1 to C10) were found not to be suitable for conventional tire tread processes.

2. Example

The tire compositions according to the present invention were prepared in the following materials and composition ratios.

<Two kinds of carbon black composition>

&Lt; Carbon black three-component composition and commercial standard tire composition >

&Lt; Evaluation of physical properties &

The properties of the tire compositions and commercial standard tire compositions of Examples 1 to 4 were measured.

As can be seen from the above table, the tire composition according to the present invention, which comprises two or three kinds of carbon blacks as compared with a standard tire containing only one type of carbon black, not only has excellent electrical conductivity (low electric resistance) Wear resistance is also excellent. In addition, it can be seen that other physical properties are kept excellent as compared with standard tires. (D1, D2, D4, and D5) are very useful because they have very low electrical resistivity. In particular, when three types of carbon black are included (T1 and T2) Is more preferable.

Accordingly, in the case of manufacturing a tire using the tire composition according to the present invention, it is possible to measure the tread deformation, the road humidity, the ground pressure and the road surface condition without using a separate pressure sensor or other sensor device, The sensor function of the tread is maintained until the life of the tire is exhausted, unlike the conventional tire which can not maintain or replace the sensor even if the sensor fails, And it is possible to measure the ground pressure directly and at the whole area, and thus it is possible to perform remarkably more precise measurement than in the prior art.

The description of the presented embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features presented herein.

Claims (18)

A rubber blend containing a synthetic rubber selected from cis-1,4-polybutadiene rubber and styrene-butadiene rubber and natural rubber in a ratio of 1: 1 to 9: 1;
10 to 35 parts by weight of a first carbon black based on 100 parts by weight of the total rubber component;
5 to 10 parts by weight of a second carbon black based on 100 parts by weight of the total rubber component, said second carbon black having a BET surface area of 35 to 45 m 2 / g;
The total amount of the second carbon black and the third carbon black is 5 to 10 parts by weight based on 100 parts by weight of the total rubber component, and the third carbon black has a BET surface area of 100 to 121 m 2 / g; And
0.1 to 1 part by weight of graphene oxide based on 100 parts by weight of the total rubber component;
&Lt; / RTI &gt;
The conductive tire composition according to claim 1, wherein the first carbon black is contained in an amount of 15 to 30 parts by weight based on 100 parts by weight of the total rubber component. The conductive tire composition of claim 1, wherein said first carbon black comprises from 20 to 25 parts by weight based on 100 parts by weight of the total rubber component. The conductive tire composition of claim 1, wherein the first carbon black has a BET surface area of 1270 m 2 / g. delete The conductive tire composition of claim 1, wherein the second carbon black has a BET surface area of 35 to 40 m 2 / g. delete delete The conductive tire composition according to claim 1, wherein the synthetic rubber is cis-1,4-polybutadiene rubber. The conductive tire composition according to claim 1, wherein the synthetic rubber is styrene-butadiene rubber. The conductive tire composition of claim 1 wherein the ratio of synthetic rubber to natural rubber is 9: 1. The conductive tire according to any one of claims 1 to 4, 6, and 9 to 11, further comprising 0.1 to 1 part by weight of carbon nanotubes based on 100 parts by weight of the total rubber component Composition. delete 13. The conductive tire composition of claim 12, wherein the carbon nanotubes are multi-walled carbon nanotubes. The conductive tire composition of claim 1, wherein the graphene oxide is reduced graphene oxide. The process according to any one of claims 1 to 4, 6 and 9 to 11, wherein the precipitated silica having a BET surface area of 150 to 200 m &lt; 2 &gt; / g is used in an amount of 5 to 15 By weight of the composition. A conductive tire produced from the conductive tire composition according to any one of claims 1 to 4, 6, and 9 to 11. 17. A method for measuring abrasion, road humidity, ground pressure, road surface condition, or earthquake vibration of a tire with the conductive tire according to claim 17.

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