KR20220153973A - Pneumatic tire with excellent durability and wear-resistance - Google Patents

Abstract

The present invention discloses a pneumatic tire with excellent durability and wear-resistance. The pneumatic tire with excellent durability and wear-resistance according to the present invention includes tread rubber containing raw material rubber, silica, and a silane coupling agent. The silane coupling agent is represented by chemical formula 1 below. Accordingly, when the silane coupling agent is used, workability and reinforcing properties are improved to increase a crosslinking density of the rubber composition and secure abrasion performance of the same at the same time such that durability and abrasion performance can be improved.

Description

Pneumatic tire with excellent durability and wear-resistance}

The present invention relates to a pneumatic tire with excellent durability and abrasion resistance, and more particularly, by improving processability and reinforcing properties to increase the crosslinking density of a rubber composition and at the same time to secure abrasion performance, durability and abrasion resistance with improved durability and abrasion resistance It's all about good pneumatic tires.

The tire tread part is a part that directly contacts the ground while the vehicle is moving, and it needs to have excellent characteristics such as tire and tire wear resistance, rolling resistance that affects fuel efficiency, and tensile strength.

Among various additives used in these tire tread rubber compositions, carbon black was used as a main filler in order to improve wear resistance and tensile strength.

However, there is a problem of low fuel consumption performance and reduced wet road braking performance. To improve this, silica is widely used as a substitute for carbon black.

When such silica is used as a reinforcing material in a tire rubber composition, it has the advantage of improving wet road friction and reducing rolling resistance, but has poor miscibility with non-polar rubber due to strong polar group (-OH) and strong cohesive force between silica. There are disadvantages from the side.

In order to solve this problem, a silane coupling agent was developed and used, and the most widely used silane coupling agent is Bis (triethoxysilypropyl) tetrasulfide; TESPT) is used, but recently, mercaptosilane, which has excellent performance, is used.

Mercaptosilane has advantages of reducing volatile organic compound (VOC) emission, improving filler dispersibility, and improving rolling resistance, exothermic properties, and wear performance.

However, it is known that the reaction with the polymer is 100% due to the nature of the mercapto group (-SH) of such mercaptosilane, and the scorch time is short, resulting in a decrease in processability and a decrease in reinforcing properties.

Japanese Unexamined Patent Publication No. 2020-83976 (2020.06.04)

Therefore, the technical problem to be solved by the present invention is to improve processability and reinforcing property to increase the crosslinking density of the rubber composition and at the same time to secure abrasion performance to provide a pneumatic tire with improved durability and abrasion resistance with improved durability and abrasion resistance. .

In order to solve the above-mentioned technical problem, the present invention includes a tread rubber containing raw material rubber, silica and a silane coupling agent, and the silane coupling agent is an air filler with excellent durability and wear resistance, characterized in that represented by the following formula (1) provide tires.

<Formula 1>

(R1 is an alkyl group having 5 to 20 carbon atoms, R2 is an alkyl group having 1 to 3 carbon atoms, x is an integer of 1 to 5, and R3 is an alkoxy group)

According to another embodiment of the present invention, 1 to 20 parts by weight of the silane coupling agent may be included with respect to 100 parts by weight of the raw rubber.

According to another embodiment of the present invention, the silane coupling agent may further include a compound represented by Formula 2 below.

<Formula 2>

According to another embodiment of the present invention, the silane coupling agent may further include a compound represented by Formula 3 below.

<Formula 3>

According to the pneumatic tire having excellent durability and wear resistance according to the present invention, the crosslinking density of the rubber composition is increased by improving processability and reinforcing property, and at the same time, abrasion performance is secured to exhibit the effect of improving durability and abrasion performance.

Hereinafter, the present invention will be described in more detail.

Hereinafter, examples will be described in detail to aid understanding of the present invention, but the following examples are only illustrative of the content of the present invention, and the scope of the present invention is not limited to the following examples.

The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

In addition, although the present invention describes specific parts in detail, it will be clear to those skilled in the art that these specific descriptions are only preferred embodiments, and the scope of the present invention is not limited thereby. However, it will be said that the substantial scope of the present invention is defined by the appended claims and their equivalents.

The pneumatic tire having excellent durability and abrasion resistance according to the present invention includes tread rubber containing a raw material rubber, silica, and a silane coupling agent, and the silane coupling agent is represented by Formula 1 below.

<Formula 1>

(R1 is an alkyl group having 5 to 20 carbon atoms, R2 is an alkyl group having 1 to 3 carbon atoms, x is an integer of 1 to 5, and R3 is an alkoxy group)

In Formula 1, if the carbon number of R1 is less than 5, there is a problem in that the formation of a bonded network with the polymer is deteriorated. Conversely, if it exceeds 20, the bond length is increased, and the reaction with silane due to steric hindrance may be reduced.

In addition, when R2 has more than 3 carbon atoms, the bond length (chain length) becomes longer, and rather physically shields the surface of silica, thereby inhibiting the reaction with silane.

In addition, R3 can use an ethoxy group and a methoxy group, and since the methoxy group is harmful to methanol generated as a by-product during mixing, a separate treatment is required for this.

For example, an esterified silane coupling agent such as Formula 2 below can be seen.

<Formula 2>

In addition, the coupling agent in which the carbon number of R1 is increased in the esterified silane coupling agent can be seen in Chemical Formula 3.

<Formula 3>

In addition, 1 to 20 parts by weight of the silane coupling agent may be included with respect to 100 parts by weight of the raw rubber. If it is less than 1 part by weight, problems with fairness and wear characteristics may occur, and conversely, if it exceeds 20 parts by weight, physical properties Not only this drop, but also the rolling resistance characteristic can be reduced.

The raw rubber may include natural rubber, synthetic rubber, or a mixture thereof.

The synthetic rubber includes styrene butadiene rubber, butadiene rubber, butyl rubber, emulsion polymerization styrene butadiene rubber (E-SBR), solution polymerization styrene butadiene rubber (S-SBR), epichlorohydrin rubber, nitrile rubber, hydrogenated nitrile rubber, Brominated polyisobutyl isoprene-co-paramethyl styrene (BIMS) rubber, urethane rubber, fluoro rubber, silicone rubber, styrene ethylene butadiene styrene copolymer rubber, ethylene propylene rubber, ethylene propylene diene monomer It may be at least one selected from the group consisting of rubber, hypalon rubber, chloroprene rubber, ethylene vinyl acetate rubber, and acrylic rubber.

In addition, the silica may have a BET surface area of 90 to 250 m 2 / g.

In addition, the tread rubber according to the present invention may further include carbon black, and it is preferable to use particles having a specific surface area of 140 m 2 /g or less in terms of dispersion and abrasion.

On the other hand, in the formulation of the tread rubber according to the present invention, functional additives such as antioxidants, sulfur, DPG, zinc oxide, stearic acid, etc., as well as carbon black, may be further included in addition to the raw material rubber, silica, and silane coupling agent. Of course.

Comparative Examples 1 to 3, Examples 1 and 2

Tread rubber was prepared by mixing the raw materials shown in Table 1 below.

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 SBR 73 73 73 73 73 BR 27 27 27 27 27 silica 70.0 70.0 70.0 70.0 70.0 Silane coupling agent 1 7.0 Silane coupling agent 2 7.0 Silane coupling agent 3 7.0 Silane coupling agent 4 7.0 carbon black 4.4 4.4 4.4 4.4 4.4 zinc oxide 2.6 2.6 2.6 2.6 2.6 stearic acid 1.8 1.8 1.8 1.8 1.8 antioxidant 1.3 1.3 1.3 1.3 1.3 sulfur 1.3 1.3 1.3 1.3 1.3 DPG 1.8 1.8 1.8 1.8 1.8

Unit: parts by weight

1. SBR: Styrene content 25%, butadiene content 63%

2. BR : KBR01 (KKPC Company)

3. Silica: Silica with a nitrogen adsorption specific surface area of 210 m ² /g

4. Silane coupling agent 1: Bis-(triethoxysilyl-propyl)-tetrasulfide (TESPT, Si-69)

5. Silane coupling agent 2: 3-(Triethoxysilyl)propanethiol, reaction products with ethoxylated C13-alcohol (Mercapto Silane)

6. Silane coupling agent 3: Silane coupling agent represented by Formula 2

7. Silane coupling agent 4: Silane coupling agent represented by Formula 3

8. Carbon black: Carbon black with a DBP surface area of 100 m ² /g

9. Zinc Oxide: Zinc Oxide

10. Stearic acid: LG Household & Health Care (ELOFAD TH100)

11. Anti-aging agent: N-(1,3-dimethylbutyl)-N'-phenyl-P-phenylenediamine (KUMANOX 13)

12. Hwang : Miwon Chemical (MIDAS-101)

13. DPG: N,N'-diphenylguanidine

For each of the rubber specimens prepared in the above Examples and Comparative Examples, the properties of Mooney viscosity, tensile properties (Tensile), dynamic viscoelasticity (DMA), and abrasion (Din Abrasion) were measured according to ASTM-related regulations, and the results are shown in Table 2 below.

Item Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Crosslink Density (x10 ^-5 ) 9.40 9.15 9.21 9.61 9.42 Mooney viscosity MV@125℃ 57 74 - 69 63 T05 26.1 16.3 - 25.1 25.3 MV@100℃ 64 83 100 73 70 tensile properties Hardness 65 65 73 66 71 300%-M 137 132 117 139 135 T.S 210 198 210 208 199 E.B. 362 372 366 366 376 DMA Tg -23 -22 -23 -23 -22 tanδ@0℃
[Index] 0.312
[100] 0.328
[105] 0.304
[97] 0.332
[106] 0.295
[95] tanδ@70℃
[Index] 0.115
[100] 0.097
[116] 0.125
[91] 0.100
[113] 0.118
[97] DIN Loss(g)
[Index] 0.120
[100] 0.141
[83] 0.159
[68] 0.111
[108] 0.120
[100]

Among the Mooney viscosity, MV @ 100 ° C., when a compounded rubber is put between the upper and lower rotors with several grooves in the circumferential direction and rotated at 100 ° C., shear behavior is formed between the rotors and the resulting torque (to the rotating rotor Rubber's resistance to pressure) is measured, and the lower the viscosity value, the better the fairness. However, if it is too low, the elasticity decreases, making it difficult to exhibit the tire rubber characteristics.

Among the Mooney viscosity, MV@125°C means the minimum torque value of viscosity in the Mooney viscosity measurement at 125°C.

Among the Mooney viscosity, T05 (Moonye scorch time) means the time (min) at ML+5unit, and the ML means the time (min) when the viscosity has the minimum torque value in the Mooney viscosity measurement at 5 ° C. .

Hardness is a real value, and the higher the value, the better the hardness.

300% modulus (Modulus) is the tensile strength of a rubber specimen at 300% elongation, measured according to the ASTM standard, and the higher the value, the better the tensile strength.

T.S is the value obtained by dividing the maximum tensile load until the test piece breaks in the tensile test of the material by the cross-sectional area of the test piece before the test, and the higher the number, the better the tensile strength.

E.B is the elongation rate at which the material elongates during the tensile test, and the higher the value, the better the elongation rate.

Tg means the temperature at which polymer branches become active and begin to move due to the heat of the polymer material.

tanδ@ 0°C is measured by a DMA (Dynamic Mechanical Analysis) tester and is the result of measurement at 11 Hz, and is used as an index of wet road braking performance. The higher the value, the better the wet road braking performance.

tanδ @ 70 ° C is measured by a DMA (Dynamic Mechanical Analysis) tester and is the result of measurement at 11 Hz, and is used as an index of rolling resistance performance. The lower the number, the better the rolling resistance performance.

The DIN abrasion test is an item evaluated to predict tire abrasion, and the lower the number, the better the abrasion characteristics.

Referring to Table 2, in the case of the examples according to the present invention, it can be seen that the scorch time is longer than that of the conventional comparative example, and the workability is greatly improved, but the modulus and TS characteristics are similar to those of the prior art.

In addition, the embodiment of the present invention was able to lower the Mooney viscosity from 83 to 73 than the comparative example, and it can be confirmed that the RR performance and wear resistance were improved due to the increased crosslinking density.

Item Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 ECE-R30 hour
Index 100 99 97 103 101 DOT-139(E) TimeIndex 100 100 98 102 100 wear and tear Wear Index 100 99 95 105 102

Table 3 is a table showing the durability and abrasion test results of the finished tire product by manufacturing a tire of 205/60 R16 TA31 PCR standard as a tread using the tread rubber composition according to Examples and Comparative Examples as a tread.

Looking at Table 3 above, it can be seen that the evaluation results according to the examples according to the present invention have the best wear performance.

Therefore, it can be seen that even when the silane coupling agent according to the present invention is added to the rubber composition, it exhibits an effect of preventing deterioration in workability and wearability, which are disadvantages of conventional mercaptosilane, while maintaining existing physical properties.

Claims (4)

Including tread rubber containing raw material rubber, silica and a silane coupling agent,
The silane coupling agent is a pneumatic tire with excellent durability and wear resistance, characterized in that represented by the following formula (1).
<Formula 1>

(R1 is an alkyl group having 5 to 20 carbon atoms, R2 is an alkyl group having 1 to 3 carbon atoms, x is an integer of 1 to 5, and R3 is an alkoxy group)
According to claim 1,
A pneumatic tire with excellent durability and wear resistance, comprising 1 to 20 parts by weight of the silane coupling agent based on 100 parts by weight of the raw rubber.
According to claim 1,
A pneumatic tire with excellent durability and wear resistance, characterized in that the silane coupling agent further comprises a compound represented by Formula 2 below.
<Formula 2>

According to claim 1,
A pneumatic tire with excellent durability and wear resistance, characterized in that the silane coupling agent further comprises a compound represented by Formula 3 below.
<Formula 3>