KR100257966B1 - A rubber composition for tread of tire - Google Patents

Abstract

PURPOSE: A rubber composition used for a tread portion of a pneumatic tire obtained by using cresol type alkylphenolformaldehyde resin alone is provided, which increases both modulus and hysterisis. CONSTITUTION: This tire tread rubber composition comprises 100 parts by weight of a rubber composition comprising 50 to 100 parts by weight of natural rubber or styrene-butadiene copolymer rubber and 0 to 50 parts by weight of polybutadiene rubber; 0.1 to 10 parts by weight of cresol type alkylphenolformaldehyde resin of formula; 30 to 60 parts by weight of carbon black having a nitrogen absorption specific surface area (N2SA) of 90 to 130 m2/g a dibutyl phthalate absorption amount of 100 to 160 ml/100g and an additive. In formula, n is 2 to 5, and R is OH or CH3.

Description

Rubber composition for tread of pneumatic tire

The present invention relates to a rubber composition for tread of pneumatic tire, and more particularly, by using a cresol type alkylphenol formaldehyde resin having a structure of Formula 1 below, the modulus and hysteresis of pneumatic tire tread portion rubber are simultaneously increased. A rubber composition for tread of pneumatic tires.

Formula 1

Wherein n is an integer from 2 to 5 and R is OH or CH ₃ .

As a method for improving the modulus of tire rubber and improving hysteresis at the same time, there are a method of increasing the addition amount of carbon black and the processing oil, which are reinforcing fillers, and a reinforcing resin. However, when the amount of reinforcing filler is increased to increase the modulus of the rubber, if the amount is added too much beyond the appropriate amount, the other performance of the rubber is degraded, and if it is severe, it does not serve as a rubber for pneumatic tires.

Therefore, in order to obtain the hysteresis improvement and reinforcement effect of rubber | gum simultaneously, it is common to add reinforcement resin. However, when the resin is used, the reinforcing effect is very small compared to the method of increasing the amount of reinforcing filler added. Table 1 lists several types of reinforcing resins currently commercially available.

Classification of Reinforcement Resin Natural resin rosin Sword, Towel, Wood Rosin Denatured Rosin High Rosin Terpenes α, β-pinene Synthetic resin Petroleum Aromatic C9 resin Aliphatic C5 Resin Coal-based Aromatic C9 resin Phenolic Resol type Novolac Other modified resin

When phenolic resins, especially alkylphenol formaldehyde resins or cashew resins, are used together with crosslinking agents such as HMT (hexamethylenetetraamine) or HMMM (hexamethoxymethylmelamine), the reinforcing effect is very excellent. It is applied to the rubber | gum for a batt or the rubber for a bead filler. However, when the phenolic resin and the crosslinking agent are used together, only the modulus of the rubber is increased and the hysteresis is rather reduced.

The present inventors have studied in order to solve the problems of the prior art as described above, and when the cresol type alkylphenol formaldehyde resin is used alone, it has been found that the modulus and hysteresis of the pneumatic tire tread portion rubber can be simultaneously increased. It came to invention.

Accordingly, an object of the present invention is to provide a rubber composition for treads of pneumatic tires using a cresol type alkylphenol formaldehyde resin at the same time increasing modulus and hysteresis.

The present invention relates to cresol type alkylphenols having a structure of the following Chemical Formula 1 with respect to 100 parts by weight of a total rubber component formed by mixing 50 to 100 parts by weight of natural rubber or styrene-butadiene copolymer rubber and 0 to 50 parts by weight of polybutadiene rubber. 0.1 to 10 parts by weight of formaldehyde resin, 30 to 60 parts by weight of carbon black having a nitrogen adsorption specific surface area of 90 to 130 m 2 / g and DBP oil absorption of 100 to 160 ml / 100 g, and a rubber composition for tread of a conventional pneumatic tire It is a rubber composition for tread of a pneumatic tire which consists of an additive used for the.

Formula 1

Wherein n is an integer from 2 to 5 and R is OH or CH ₃ .

Hereinafter, the present invention will be described in detail.

In the present invention, with respect to 100 parts by weight of the total rubber component formed by mixing 50 to 100 parts by weight of natural rubber or styrene-butadiene copolymer rubber and 0 to 50 parts by weight of polybutadiene rubber, cresol type alkylphenol form having the structure of Formula 1 0.1 to 10 parts by weight of the aldehyde resin is used.

Cresol type alkylphenol formaldehyde resin (hereinafter, referred to as RF-resin) having the structure of Chemical Formula 1 has a very small molecular weight compared to rubber, and thus acts as a kind of plasticizer in rubber. Therefore, the hysteresis of the rubber increases when such a resin is added.

In addition, the RF-resin has a significantly higher glass transition temperature (Tg) compared to rubber. Therefore, the hardness of the resin is higher than that of rubber in the temperature range used in daily use, and the functional group of the resin is easy to bond with the rubber (physical adsorption mainly and sometimes chemical bonding may occur), thus serving as a kind of organic filler. have. This increases the modulus of the rubber in the low strain region.

However, when the RF-resin is used in combination with the crosslinking agent HMT or HMMM, the desired modulus can be obtained, but the hysteresis of the rubber is rather reduced, and thus the desired performance is not obtained. In other words, when the RF-resin and the crosslinking agent are used together, a composite is formed between the crosslinking agent and the RF-resin and the rubber, which significantly increases the modulus of the rubber, but rather reduces the hysteresis.

The RF-resin is preferably used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the total rubber component. When the amount of the RF-resin added in excess of 10 parts by weight is used, the modulus of the rubber increases gradually but the hysteresis performance decreases. In addition, when too much resin is added, not only proper strength and hysteresis performance can be obtained, but also the workability of the rubber is difficult to be processed in the field, and thus it cannot be applied to products.

The carbon black used in the present invention has a nitrogen adsorption specific surface area of 90 to 130 m 2 / g and a DBP oil absorption of 100 to 160 ml / 100 g, preferably 30 to 60 parts by weight based on 100 parts by weight of the entire rubber component. do.

When the nitrogen adsorption specific surface area of the carbon black is less than 90 m 2 / g, the filling effect of the rubber is inadequate, and when the carbon black exceeds 130 m 2 / g, the heat generation of the rubber is severe and unsuitable for use. In addition, when the DBP oil absorption amount is less than 100ml / 100g, the field workability is poor and the filling effect of the rubber is also lowered, and when it exceeds 160ml / 100g, proper hysteresis performance is not obtained.

Moreover, the additive used for the tread rubber composition of a normal pneumatic tire is used for the rubber composition of this invention.

Hereinafter, the present invention will be described in more detail with reference to Examples. The present invention is not limited to the following Examples.

Example

Example 1

With respect to 100 parts by weight of natural rubber, a carbon sheet was prepared by blending carbon black, process oil, activator, preservative, RF-resin, sulfur, accelerator, retarder as shown in Table 2 below. The rubber sheet was vulcanized for 30 minutes in a 150 ° C. vulcanization press to prepare test specimens, and then modulus and hysteresis were measured.

Modulus measurement was carried out with a tensile tester (Model 4502) manufactured by Instron, by cutting the specimen into dumbbells, and the hysteresis measurement was carried out using a rectangular (10 mm (w) x 30 mm (l) x 2.5 mm ( t)) The loss modulus (G ") value of the dynamic viscoelastic properties of the rubber obtained by applying the torsional strain was measured (measured by RDS tester manufactured by Rheometrics). Indicated.

Example 2

Except for using 10 parts by weight of RF-resin, the same method as in Example 1 was repeated to measure the modulus and hysteresis, the results are shown in Table 3 below.

Example 3

With respect to 100 parts by weight of the total rubber components mixed with 70 parts by weight of natural rubber and 30 parts by weight of polybutadiene rubber, carbon black, process oil, activator, preservative, RF-resin, sulfur, accelerator, retardant are shown in Table 2 below. The rubber sheet was prepared by blending. Modulus and hysteresis were measured in the same manner as in Example 1, and the results are shown in Table 3 below.

Example 4

To 100 parts by weight of styrene-butadiene copolymer rubber, carbon black, processed oil, activator, preservative, RF-resin, sulfur, accelerator, retardant were blended as shown in the following Table 2 to prepare a rubber sheet. Modulus and hysteresis were measured in the same manner as in Example 1, and the results are shown in Table 3 below.

Example 5

The carbon black, the processing oil, the activator, the lubricating agent, the RF-resin, the sulfur, the accelerator, and the retardant are described in Table 2 with respect to 100 parts by weight of the total rubber components mixed with 70 parts by weight of styrene-butadiene copolymer rubber and 30 parts by weight of polybutadiene rubber. A rubber sheet was prepared by blending as shown. Modulus and hysteresis were measured in the same manner as in Example 1, and the results are shown in Table 3 below.

Comparative Example 1

Except for using 15 parts by weight of RF-resin, the same method as in Example 1 was repeated to measure the modulus and hysteresis, the results are shown in Table 3 below.

Comparative Example 2

Except that no RF-resin was used, the same method as in Example 1 was repeated to measure modulus and hysteresis, and the results are shown in Table 3 below.

Comparative Example 3

The same procedure as in Example 1 was repeated except that 5 parts by weight of resin 1 (naturally modified rosin (high rosin)) was used without using RF-resin, and the modulus and hysteresis were measured. 3 is shown.

Comparative Example 4

The same procedure as in Example 1 was repeated except that 5 parts by weight of resin 2 (total oil rosin / C9 petroleum resin / terpene resin melt mixture) was used, and the modulus and hysteresis were measured. The results are shown in Table 3 below.

Comparative Example 5

The same procedure as in Example 1 was repeated except that 5 parts by weight of Resin 3 (total oil rosin / C9 petroleum resin / maleic acid admixture mixture) was not used, and the modulus and hysteresis were measured. The results are shown in Table 3 below.

Comparative Example 6

The same procedure as in Example 1 was repeated except that 5 parts by weight of resin 4 (DCPD (dicyclopentadiene) hydrocarbon resin) was used, and the modulus and hysteresis were measured. It is shown in Table 3 below.

Comparative Example 7

5 parts by weight of RF-resin and 3 parts by weight of HMMM were used, and the remaining composition was prepared in the same manner as in Example 1, and the modulus and hysteresis of the specimens were measured in the same manner as in Example 1, and the results were as follows. Table 3 shows.

Comparative Example 8

Except that no RF-resin was used, the remaining components were prepared in the same manner as in Example 3, test specimens were prepared, and the modulus and hysteresis of the specimens were measured in the same manner as in Example 1. Shown in

Comparative Example 9

Except that no RF-resin was used, the remaining components were prepared in the same manner as in Example 4, and the modulus and hysteresis of the specimens were measured in the same manner as in Example 1, and the results are shown in Table 3 below. Shown in

Comparative Example 10

Except that no RF-resin was used, the remaining components were prepared in the same manner as in Example 5, and the modulus and hysteresis of the specimens were measured in the same manner as in Example 1, and the results are shown in Table 3 below. Shown in

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Natural rubber 100 100 70 100 100 Styrene-butadiene copolymer rubber 100 70 40 Polybutadiene rubber 30 30 5 Carbon black 40 40 40 40 40 40 6 Processing oil 5 5 5 5 5 5 4 Active agent 6 6 6 6 6 6 Labor 4 4 4 4 4 4 Resin 1 Resin 2 Resin 3 Resin 4 2.5 RF-resin 5 10 5 5 5 15 One brimstone 2.5 2.5 2.5 2.5 2.5 2.5 0.5 accelerant One One One One One One Retardant 0.5 0.5 0.5 0.5 0.5 0.5 HMMM

(Continued table)

Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Natural rubber 100 100 100 100 100 70 Styrene-butadiene copolymer rubber 100 70 Polybutadiene rubber 30 30 Carbon black 40 40 40 40 40 40 40 40 Processing oil 5 5 5 5 5 5 5 5 Active agent 6 6 6 6 6 6 6 6 Labor 4 4 4 4 4 4 4 4 Resin 1 5 Resin 2 5 Resin 3 5 Resin 4 5 RF-resin 5 brimstone 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 accelerant One One One One One One One One Retardant 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 HMMM 3

Resin 1: Naturally Modified Rosin (High-Rosin)

Resin 2: Toluene Rosin / C9 Petroleum Resin / Terpene Resin Melt Mixture

Resin 3: Tole oil rosin / C9 petroleum resin / maleic acid adduct mixture

Resin 4: DCPD (dicyclopentadiene) hydrocarbon resin

A mixture of aromatic and naphthalene oils was used as the covalent oil, sunprax 682, which is a wax as a preservative, zinc oxide as the activator, mercapto benzothiazole vulcanization accelerator as the accelerator, and PVI as the retardant. .

Modulus and hysteresis measurement results of each Example and Comparative Example Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Modulus 10% M 6.5 8.3 6 5.6 5.3 9.9 4.4 20% M 9.6 11.6 9 8.4 7.9 13.6 7.5 30% M 12.3 15.0 11.9 11.3 10.7 17.8 10 50% M 17.1 21.8 16.1 15.6 15 26.1 13.7 100% M 28.3 32.1 27.3 26.2 25.2 38.6 23 G "(× 10 ⁸ ) 0 ℃ 0.3135 0.2951 0.2956 0.3342 0.3108 0.2569 0.1867 20 ℃ 0.2371 0.2035 0.2184 0.2621 0.239 0.1895 0.1206 40 ℃ 0.1933 0.1721 0.1753 0.2119 0.2052 0.1456 0.08564 60 ℃ 0.1883 0.1596 0.1673 0.2079 0.1934 0.1182 0.07452 80 ℃ 0.1769 0.1366 0.1587 0.1956 0.1791 0.0985 0.06305 100 ℃ 0.1682 0.1125 0.1486 0.1834 0.1599 0.08931 0.0546

(Continued table)

Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Modulus 10% M 4.5 4.6 4.6 4.1 8.9 3.2 3.0 2.8 20% M 7.4 7.4 7.4 6.8 11.1 5.9 5.5 5.3 30% M 9.6 9.7 9.7 8.7 14.3 8.6 8.1 7.6 50% M 12.6 12.4 12.3 11.6 21.2 10 9.3 8.3 100% M 21 21.6 21.5 19.6 33.7 19 17.8 16.3 G "(× 10 ⁸ ) 0 ℃ 0.1978 0.2582 0.2321 0.2296 0.2296 0.1795 0.2432 0.2321 20 ℃ 0.1257 0.179 0.1571 0.1501 0.1349 0.1131 0.1916 0.1617 40 ℃ 0.08967 0.1351 0.1164 0.1098 0.0864 0.08723 0.1514 0.1268 60 ℃ 0.07498 0.116 0.1035 0.0953 0.07352 0.07323 0.1366 0.1129 80 ℃ 0.06092 0.0955 0.08718 0.0828 0.0651 0.06235 0.1255 0.09716 100 ℃ 0.05162 0.07991 0.07647 0.07132 0.05213 0.05133 0.09891 0.08643

* Modulus: unit is kg / cm 2, in this case, does not mean the slope in the stress-strain curve, but means the stress value at each elongation (strain) (the 10% M is applied to the specimen when the specimen is stretched 10% Stress).

* G "(loss modulus) measurement condition: Temperature sweep at 10Hz frequency, 0.5% strain

As shown in Table 3, it can be seen that the hysteresis is significantly increased when using the RF-resin in the rubber composition for tread compared to the rubber not using the RF-resin. In addition, the results of the comparison of the modulus of the rubber shows that the case of using the existing reinforcing resin (Comparative Examples 3 to 6) shows that the reinforcing effect is hardly shown, but the reinforcing effect is used when the RF-resin according to the present invention is used. It can be seen that is apparent.

Comparative Example 7 shows that RF-resin is applied to rubber together with a crosslinking agent, HMMM. In this case, the modulus of rubber is significantly increased (excellent reinforcing effect), but the hysteresis performance of rubber is not significantly improved. Can be.

Comparative Example 1 is an example using more than 10 parts by weight of 15 parts by weight of the RF-resin, as can be seen in Table 3, the modulus of the rubber than the examples 1 and 2 increased but the hysteresis performance was reduced, Its workability is so poor that it cannot be applied to products

According to the present invention, the modulus and hysteresis of the rubber can be simultaneously increased by using a cresol type alkylphenol formaldehyde resin in the tread rubber composition of the pneumatic tire.

Claims (1)

Cresol type alkylphenol formaldehyde resin 0.1 having a structure represented by the following formula (1) based on 100 parts by weight of a total rubber component formed by mixing 50 to 100 parts by weight of natural rubber or styrene-butadiene copolymer rubber and 0 to 50 parts by weight of polybutadiene rubber. To 10 parts by weight, nitrogen adsorption specific surface area of 90 to 130 m 2 / g, 30 to 60 parts by weight of carbon black having a DBP oil absorption of 100 to 160ml / 100g and additives used in the tread rubber composition of conventional pneumatic tires A rubber composition for tread of a pneumatic tire, characterized in that consisting of. Formula 1

Wherein n is an integer from 2 to 5 and R is OH or CH ₃ .