KR100750948B1 - Tire rubber composition with excellent wear resistance - Google Patents

Abstract

The present invention relates to a tire rubber composition, and more particularly, by applying a nanocomposite prepared by sufficiently dispersing an organicized nanoclay and a stabilizer in an aqueous state, adding oil to emulsify, and then mixing it with rubber latex as a raw material rubber. The present invention relates to a tire rubber composition having improved mechanical properties and wear performance.

Description

Tire rubber composition excellent in wear resistance {TIRE RUBBER COMPOSITION HAVING IMPROVED ABRASION RESISTANCE}

1 is a process flow diagram schematically showing a manufacturing process of a nanocomposite used in the present invention.

The present invention relates to a tire rubber composition, and more particularly, by applying a nanocomposite prepared by sufficiently dispersing an organicized nanoclay and a stabilizer in an aqueous state, adding oil to emulsify, and then mixing it with rubber latex as a raw material rubber. The present invention relates to a tire rubber composition having improved mechanical properties and wear performance.

When nanoclays are applied to rubber compositions, major characteristics such as changes in physical properties and abrasion characteristics may appear depending on the degree of dispersion. This is because the rubber layer is intercalated between the plate-shaped nanoclays or the nanoclays are completely dispersed to improve mechanical properties. Therefore, the dispersibility of the nanoclay can be said to be a major factor that determines the properties of the rubber composition.

There are two ways to improve the dispersion properties of nanoclays. The first method is to facilitate the reaction with polymers by organicizing the properties of nanoclays (see Materials Science and Engineering, 28, 1 to 63, (2000)), and the second method is a method of inducing dispersion of nanoclays by adjusting a method for preparing a rubber composition including nanoclays.

There are three methods for preparing a rubber composition containing such nanoclays, and typical ones include a method of inserting rubber molecules into nanoclays by a conventional mixing method, and mixing and dispersing by shearing force. A second method is to induce dispersion by mixing nanoclay and latex (aqueous raw material rubber in aqueous solution) in aqueous solution (Journal of Applied Polymer Science, 788, 1873-1878 (2000)). A third method is to induce dispersion by mixing raw rubber with swelling in a solvent such as toluene or tetrahydrofuran (THF) and mixing it with a solution of nanoclay dispersed in the solvent (see Elastomer, 39). (1), 51-60 (2004).

Looking at the patent case, the application of nanoclay as a raw material of the rubber composition is mentioned in US Patent No. 6,858,665, the content of which is added to the nanoclay-containing rubber composition by adding a quaternary ammonium salt to the plate-like nanoclay is inserted into the rubber Induced to be completely dispersed.

In Korean Patent Application No. 10-2004-0020530, nano-reinforced resins containing phenol formaldehyde and silicate modified with CNSL (Cashew Nut Shell Liquid) are added to the raw material rubber to match the performance required for tire stability, ride comfort, etc. The physical properties are tailored to help. This overcomes the problem that the particles of the plate-shaped nanoclay are not dispersed in the rubber phase by the binding force and thus do not exhibit the expected physical properties in combination with the modified phenol formaldehyde.

In Korean Patent Registration No. 10-0497459, nanoclays are prepared in a dispersed state in an aqueous solution, latex is applied as a raw material rubber, and nanocomposites are prepared and utilized in a rubber composition to cause physical property improvement. In Korean Patent Application No. 10-2004-0040855, In the process of polymerization of styrene-butadiene rubber, nanoclay was added to prepare a nanocomposite, and the contents used as a rubber composition for a tire are presented.

Commonly proposed in the prior art is to effectively induce the dispersion of nanoclay in the raw material rubber to improve the physical properties of the rubber, but the dispersion state of the nanoclay shows a limit in the conventional mixing method of applying a short-barrier mixer In order to improve the performance, a number of contents, such as mixing conditions and facilities, should be considered. In addition, in the case of preparing the nanocomposite by dispersing the nanoclay in a solvent such as toluene, a small amount of nanoclay may be leaked in the coagulation process, thereby exhibiting dispersion of quality.

Therefore, there is a method of producing in aqueous solution as a method of inducing the production and dispersion of stable nanocomposites. However, in the above-mentioned patent documents (10-0497459, 2004-0040855), when applying the organic nanoclay to the styrene-butadiene rubber to which the oil is applied, the oil and nanoclay may react first, so that the dispersion may be rather deteriorated, ultimately nano It causes the physical properties of the rubber composition to which the composite is applied.

An object of the present invention is to improve the mechanical properties and wear performance by applying a nanocomposite as a raw material rubber to weaken the binding force between the oil and the organicized nanoclay to sufficiently emulsify the nanoclay on the latex to solve the above problems It is to provide a rubber composition.

The tire rubber composition of the present invention is a tire rubber composition comprising a raw material rubber and an ordinary additive, wherein the raw material rubber is emulsified by adding an aromatic oil after sufficiently dispersing the organicized nanoclay and a stabilizer in an aqueous solution state. Next, it is characterized by applying a nanocomposite prepared by mixing with rubber latex.

The manufacturing process of the nanocomposite used in the present invention is as follows.

The organic clay and the stabilizer are sufficiently dispersed in an aqueous solution in the reactor, and then emulsified by adding an aromatic oil. Thereafter, the prepared emulsion is stirred with a rubber latex prepared separately and mixed in an aqueous solution. The mixture is solidified in acidic cationic water, washed and finally dried to complete the nanocomposite.

The nanocomposite manufacturing process as described above is schematically shown in FIG.

In the manufacturing process of the nanocomposite used in the present invention, in order to determine the optimal injection amount of the stabilizer, the oil content is changed as shown in Table 1 based on 100 parts by weight of the solid content in the rubber latex used in the nanocomposite preparation The degree of reactivity was determined, and the optimum injection ratio was determined at the point where coagulation did not occur during oil injection.

TABLE 1

Oil / Nanoclay Behavior Changes with Stabilizer Injection

(Unit: parts by weight)

stabilizator Nanoclay oil Coagulation phenomenon (%) 0 15 37.5 95 5 15 37.5 63 10 15 37.5 24 15 15 37.5 0 20 15 37.5 0

※ When 15 parts by weight of stabilizer is applied, the oil and the organic nanoclay do not react first, so they do not aggregate, so it is possible to stir with latex in aqueous solution.

Flocculation (%) = weight of flocculated solids / weight of injected material × 100

The results in Table 1 above show that it is difficult to apply the organicized nanoclays directly to rubber latex with oil because the organicized nanoclays are first aggregated with the oil and do not disperse on the latex.

As can be seen from the results in Table 1, it is preferable to use a stabilizer of 15 to 20 parts by weight based on 100 parts by weight of the solid content in the rubber latex, when less than 15 parts by weight, agglomeration occurs, more than 20 parts by weight. It is not preferable because it is inefficient to cause other physical properties to fall.

Nanoclay and oil used in the present invention is preferably used 15 to 20 parts by weight and 30 to 37.5 parts by weight based on 100 parts by weight of solids in rubber latex.

When the content of the nanoclay is less than 15 parts by weight, agglomeration occurs, and when it exceeds 20 parts by weight, the physical properties decrease, which is not preferable. When the oil content is out of the above range, an optimal emulsified state cannot be obtained.

Stabilizers used in the present invention weaken the binding force between the oil and the nanoclay, and serves to facilitate the dispersion with latex, for example, sodium stearate, lauryl soda or potassium oleate is preferable.

The nanoclays used in the production of the nanocomposites used in the present invention are preferably all nanoclays modified (organic) with quaternary ammonium salts, and the like, and commercially available products include Cloisite-15A. As the quaternary ammonium salt used as the organic modifier, 2M2HT (dimethyl-dihydrogenated tallow quaternary ammomium) of the following formula is preferable.

HT: Hydrogen Tallow

The nanoclay used in the present invention preferably has a spacing between the platelets of 1 nm to 5 nm from the viewpoint of dispersibility.

In the rubber composition of the present invention, additives for conventional rubber compositions, for example, fillers, zincation, stearic acid, sulfur, accelerators, and the like, may be appropriately selected and added, and the selection and use of these additives are known in the art. .

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.

Example

Component formulations of the tire rubber compositions used in the test are shown in Table 2 below, and the results of measuring physical properties according to ASTM standards for the rubber compositions of Comparative Examples and Examples of the present invention are shown in Table 3 below.

Comparative Example 1

Styrenebutadiene rubber (100 parts by weight of rubber solids + 37.5 parts by weight of oil) 137.5 parts by weight, 70 parts by weight of carbon black (N-103), 3 parts by weight of zinc acid, 2 parts by weight of stearic acid, and other conventional ingredients Tire rubber compositions were prepared using additives applied to tires.

Comparative Example 2

A tire rubber composition was prepared in the same composition as in Comparative Example 1 except that 15 parts by weight of nanoclay and 15 parts by weight of a stabilizer were added according to the composition of Table 2.

<Example 1>

The latex which made styrene butadiene rubber the form of aqueous solution was prepared.

15 parts by weight of nanoclay (modifier concentration: 125 meq / 100 g nanoclay) organicized using 2M2HT, a quaternary ammonium salt as an organic modifier, and 15 parts by weight of sodium stearate as a stabilizer in an aqueous solution state After sufficient dispersion, 37.5 parts by weight of aromatic oil was added to emulsify. Thereafter, the styrene-butadiene rubber latex and the emulsion were mixed with stirring, solidified in cationic water at pH 4, washed with water, and dried in a hot air for 1 hour to obtain a nanocomposite.

167.5 parts by weight of the nanocomposite thus prepared was used as a raw material rubber, and tire rubber was made by using an additive applied to 70 parts by weight of carbon black (N-103), 3 parts by weight of zinc acid, 2 parts by weight of stearic acid, and other conventional tires. The composition was prepared.

TABLE 2

                                                                (Unit: weight part)

division Comparative Example 1 Comparative Example 2 Example 1 Styrenebutadiene rubber (with oil) 137.5 137.5 - Nanocomposite - - 167.5 Nanoclay - 15 - Stabilizer ^{1 )} - 15 - Carbon black (N-103) 70 70 70 Zinc volcano 3 3 3 Stearic acid 2 2 2 sulfur 1.7 1.7 1.7 Accelerator ^{2 )} 1.3 1.3 1.3

* Stabilizer ^{1 )} : sodium stearate

* Promoter ^{2 )} : CZ (cyclohexyl benzothiazol sulfenamide, manufactured by Flexsis: primary accelerator))

TABLE 3

                           Unit: Exponent (numerically compares Comparative Example 1 to Standard (100))

division Comparative Example 1 Comparative Example 2 Example 1 Mooney Mooney viscosity 100 103 100 Properties Hardness, Shore Method 300% Modulus (kg / ㎠) Tensile Strength (kg / ㎠) Elongation (%) 100 100 100 100 102 105 92 91 100 110 120 115 Wear Wear index 100 88 120

※ The higher the wear index, the more favorable the value.

As can be seen from the above, according to the present invention, by sufficiently dispersing the organicized nanoclay and stabilizer in an aqueous solution state, and then emulsified by adding a stabilizer, by applying the nanocomposite prepared by mixing with rubber latex as raw material rubber It is possible to obtain a tire rubber composition with improved mechanical properties and wear performance.

Claims (4)

In the tire rubber composition comprising a raw material rubber and an additive, as the raw material rubber, nanoorganisms prepared by sufficiently dispersing the organicized nanoclay and the stabilizer in an aqueous solution state, adding emulsified aromatic oils, and then mixing them with rubber latex A tire rubber composition comprising a composite. According to claim 1, wherein the nanoclay and stabilizer is used 15 to 20 parts by weight based on 100 parts by weight of solids in the rubber latex, the aromatic oil is 30 to 37.5 parts by weight based on 100 parts by weight of solids in the rubber latex Tire rubber composition, characterized in that it is used. The tire rubber composition according to claim 1 or 2, wherein the nanoclay has an interval between 1 nm and 5 nm between plates. The tire rubber composition according to claim 1 or 2, wherein the stabilizer is sodium stearate, lauryl soda or potassium oleate.

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