KR20010019161A - Tread Rubber Composition for Cure Time Shorting and Cut &Chip - Google Patents

Abstract

PURPOSE: A tread rubber composition is proposed to reduce vulcanization time and to retain cut-and-chip performance by means of specific compounds, for example zinc-2-mercaptotolu-imidazole. CONSTITUTION: A tread rubber composition is prepared by blending tetraisobutyl thiuram monosulfide as vulcanizing promotor and TBBS as sulfenamides vulcanizing promotor and adding zinc-2-mercaptotolu-imidazole to it. In case where prompt vulcanization is required, thiurams promotor such as tetramethyl thiuram disulfide(TMTD) or tetraethyl thiuram disulfide(TETD) are preferably used, although sulfenamides such as TBBS may reduce vulcanization time. The tread rubber composition can reduce vulcanization time while retaining cut-and-chip performance.

Description

Tread Rubber Composition for Curing Time Shorting and Cut & Chip & Capability

The present invention relates to a tread rubber composition in which vulcanization time is shortened and cut and chip performance is maintained.

The required performance of each part of the tire varies greatly depending on the intended use and location. Among them, the tread part of the tire in direct contact with the road surface has many effects such as braking force on the wet road surface, wear resistance, cut-and-chip and crack resistance performance. The required performance is required, and the degree of the required performance varies depending on the type and use of the vehicle in which the tire is used and the mounting position of the tire.

The required characteristics of the tread rubber of large vehicle tires are that wear resistance and cut-and-chip performance are important, and synthetic rubber with good abrasion resistance is mixed with natural rubber with good smoke characteristics, but due to the low vulcanization temperature and prolonged vulcanization due to the volume of rubber Productivity declined. Moreover, synthetic rubber is an obstacle due to the delay in the vulcanization time. Many vulcanization accelerators are used to improve this, but vulcanization accelerators serve to speed up the vulcanization time and also shorten the scorch time of rubber.

Vulcanization accelerators such as CBS (N-cyclohexyl-2-benzothiazolylsulfenamide), TBBS, MBS (N-Oxydiethylene-2-benzothiazolylsulfenamide, and MBS (Sunfenamides) type have a slowing time but have a delaying effect, but the effect is insignificant. If a fast vulcanization time is required, tetra ethyl thiuram disulfide (hereinafter referred to as TETD), tetra methyl thiuram disulfide (hereinafter referred to as TMTD), tetramethyl thiuram monosulfide Thiraums family of vulcanization accelerators, such as Tetra methyl thiuram monosulfide (TMTM), are used, but many vulcanization accelerators are used to prevent scorch defects during rubber extrusion. Additional vulcanization retardants may be used.

Since the use of a large amount of vulcanization accelerator tends to reduce the cut-and-chip performance of rubber, it is necessary to improve the vulcanization time and maintain the cut-and-chip performance while delaying the scorch time.

In order to solve the above problems, tetraisobutyl thiuram monosulfide, Curerite-IBM (hereinafter referred to as C-IBM) as a vulcanization accelerator in a mixture of natural rubber and synthetic rubber as raw rubber. After appropriate mixing of sulfenamide-based vulcanization accelerator TBBS, zinc 2-mercaptotolu-imidazole (Zinc 2-mercaptotolu-imidazole, Vanox ZMTI (hereinafter referred to as V-ZMTI)) is added to reduce vulcanization time. It is an object of the present invention to provide a tread rubber composition that maintains chip performance.

The tread rubber composition which speeds up the vulcanization time of the present invention and maintains cut and chip performance while extending the scorch time uses natural rubber and synthetic rubber as the raw material rubber and uses a known tire rubber composition which is generally used. As a vulcanization accelerator, C-IBM and sulfenamide-based TBBS ((Nt-butyl-2) -benzothiazolylsulfenamide) are properly mixed with V-ZMTI.

When styrene-butadiene rubber (SBR) is used as the synthetic rubber, if the amount of SBR used is 50 phr or more, it is not suitable as a tread rubber due to high heat generation. Therefore, when using SBR as a synthetic rubber, it is preferable to use 50 to 100 phr of natural rubber and 0 to 50 phr of SBR as a raw material rubber. On the other hand, SBR has a longer vulcanization time than natural rubber, so there is a problem of deterioration in productivity. Therefore, the type and amount of vulcanization accelerator should be used appropriately. When a large amount of sulfenide-based TBBS is used, vulcanization time is shortened, and thiuram The use of the TMTD system, which excels in shortening the vulcanization time, reduces the scorch time and also generates nitroamine, a legal regulatory substance, as a hazardous substance.

In the present invention, the vulcanization accelerator uses TBBS, which is a sulfenamide-based, and C-IBM is properly mixed to solve the problems of TBBS mentioned above.

When using C-IBM, the vulcanization time is shortened but the scorch time is extended to increase the elongation of 300, resulting in a decrease in cut-and-chip performance. The time savings are great and the scorch time is longer, but cut and chip performance is reduced. In order to improve this, it can be improved by combining V-ZMTI together.

Therefore, in the present invention, as a result of using the appropriate combination of vulcanization accelerators of C-IBM and TBBS, the vulcanization time is shortened, and the productivity is not reduced using V-ZMTI while increasing productivity. It was appropriate to use 0.1-0.5 phr and sulfenamide-based TBBS vulcanization accelerators with 0.2-0.9 phr mixed with each other as appropriate. In addition, V-ZMTI showed good results when used within the range of 0.5 to 2.0 phr. Meanwhile, Table 1 below shows the characteristics of C-IBM and V-ZMTI used in the present invention.

Table 1. Characteristics of C-IBM and V-ZMTI

Item MAKER Characteristics Remarks Curerite-IBM (Tetraisobutyl thiuram monosulfide) B.F.GOODRICH -. Long scotch-. Fast curing speed accelerant Vanox ZMTi (Zinc 2-mercaptotolu-imidazole) R. T.VANERBILT -. Low modulus. High tearing. Good fatigue resistance Antioxidant

Hereinafter, the present invention will be described by the following examples. However, these do not limit the technical scope of the present invention.

<Example 1>

Zinc oxide (ZnO-S) 4 phr, carbon black 50 phr, stearic acid (S / A) 1 phr, 100 phr of raw rubber consisting of 70 phr of natural rubber and 30 phr of SBR, 2 phr of commonly used thermal aging inhibitor, Tread rubber specimens were prepared using 2 phr of anti-ozone aging agent, 1 phr of wax, 3 phr of oil, 1.8 phr of sulfur (S), and 0.6 phr of TBBS. Rheometer, Mooney viscosity of this tread rubber specimen was prepared. , Hardness, 300 modulus, elongation (Rebound), pico (PICO), cut and chip properties were measured and the results are summarized in Table 2 below.

<Example 2>

Tread rubber specimens were prepared in the same manner as in Example 1 except that TBBS 0.44 phr and C-IBM 0.2 phr were used, and the physical properties thereof were measured and shown in Table 2 below.

<Example 3>

Tread rubber specimens were prepared in the same manner as in Example 1 except for using V-ZMTI 1.0 phr and TBBS 0.55 phr, and the physical properties thereof were measured and shown in Table 2 below.

<Example 4>

Tread rubber specimens were prepared in the same manner as in Example 1 except that V-ZMTI 1.0 phr, TBBS 0.44 phr, and C-IBM 0.15 phr were used, and the physical properties thereof were measured and the results are summarized in Table 2 below. It was.

<Example 5>

Tread rubber specimens were prepared in the same manner as in Example 1, except that the raw rubber was made of 50 phr of natural rubber, 50 phr of SBR, and 1.0 phr of V-ZMTI, 0.55 phr of TBBS and 0.2 phr of C-IBM. The results are summarized in Table 2 below.

Table 2. Tread Rubber Compositions According to Examples and Their Physical Property Results

division Example 1 Slashing Example 2 Example 3 Example 4 Example 5 Natural rubber 70.00 70 70 70 50 SBR 30.00 30 30 30 50 ZNO-S 4.00 4.00 4.00 4.00 4.00 Carbon 50.00 50.00 50.00 50.00 50.00 S / A 1.00 1.00 1.00 1.00 1.00 Thermal Aging Agent 2.00 2.00 2.00 2.00 2.00 Ozone Antioxidant (6PPD) 2.00 2.00 2.00 2.00 2.00 WAX 1.00 1.00 1.00 1.00 1.00 oil 3.00 3.00 3.0 3.0 3.0 V-ZMTI - - 1.00 1.0 1.00 S 1.80 1.80 1.80 1.80 1.80 TBBS 0.60 0.44 0.55 0.44 0.55 C-IBM - 0.20 - 0.15 0.20 Rheometer @ 145 ℃ T40 (minutes) 18.2 16.7 16.4 15.1 16.5 Total Curving Time (min) 35.2 23.5 35.8 21.8 32.4 Mooney viscosity @ 125 ℃ T5 (minutes) 30.9 37.5 29.8 33.2 31.0 T35 (minutes) 37.2 41.3 33.0 36.1 40.5 Tensile Properties Hardness (Saore A) 64 64 63 65 63 300 modulus (kg / cm ² ) 89 90 82 88 87 Elongation () 660 635 695 676 632 Exothermic Characteristics (℃) 26.0 25.4 26.9 26.3 25.3 Repulsive characteristics () 32.9 33.7 33.4 32.3 33.6 PICO (mg) 26.5 25.5 28.0 26.0 26.5 Cut & Chip 1.60 1.57 1.29 1.31 1.24 Dimatia fatigue properties (horizontal / vertical, mm) 3.2 / 4.5 10.7 / 7.1 2.2 / 3.8 3.5 / 4.6 3.9 / 4.8

* Physical properties of rheometer, tensile property, elongation, PICO, cut and chip are good as the standard is 100.

The tread rubber composition of the present invention to which V-ZMTI is added has a fast vulcanization time, but can maintain physical properties, and particularly has an effect of improving cut and chip characteristics.

Claims (1)

In 100 phr of raw rubber consisting of 50-100 phr of natural rubber and 0-50 phr of styrene-butadiene rubber, 0.1-0.5 phr of tetraisobutyl thiuram monosulfide (C-IBM) as a vulcanization accelerator, TBBS 0.2 -0.9 phr, Zinc 2-mercaptotolu-imidazole (V-ZMTI) 0.5 to 2.0 phr, characterized in that the tread rubber composition to shorten the vulcanization time and cut and chip performance.