KR20220138802A - Rubber composition for manufacturing tires comprising terminally modified liquid polybutadienes - Google Patents

Abstract

The present invention relates to a use of a terminally modified liquid butadiene compound and, more specifically, to a tire rubber composition, a tire manufactured by using the same, and a manufacturing method of the tire, wherein the tire rubber composition comprises: a terminally modified liquid butadiene rubber compound synthesized by using a chain transfer agent having a triethoxysilyl functional group and a tetra sulfide functional group, and a 1,3-butadiene monomer; and a rubber polymer. According to the present invention, by introducing a silica-friendly functional group to both ends of the chain, fuel consumption characteristics can be improved, deterioration of physical properties according to a change over time can be prevented, and abrasion resistance can be improved by lowering a glass transition temperature of the liquid butadiene rubber.

Description

Rubber composition for tires comprising both ends modified liquid butadiene compound

The present invention relates to the use of a liquid butadiene compound modified at both ends, and more particularly, to a rubber composition comprising the compound, a tire manufactured using the same, and a tire manufacturing method.

Currently, the demand for improved fuel efficiency of automobiles is continuously increasing due to the strengthening of regulations on greenhouse gas emission in countries around the world. Accordingly, the most influential factor in the paradigm change in the automobile industry is eco-friendliness, and electric vehicles have emerged as eco-friendly core technologies for reducing greenhouse gas emissions. From 2020, the EU will introduce a regulation that prevents carbon dioxide emissions from exceeding 95 g/km per vehicle based on the average number of automobiles sold, and similar fuel efficiency regulations will be implemented in major automobile consumer countries such as the United States and Japan.

As the automobile development trend changes from an internal combustion engine vehicle to an electric vehicle, tires with performance suitable for electric vehicles are also required. Due to the limited battery capacity of electric vehicles, a dramatic reduction in tire rolling resistance is required to ensure a long driving range. And, due to the characteristics of electric motors, it is also essential to improve abrasion resistance to withstand the high torque pouring from the beginning of acceleration and the high load of the motor/battery.

In 1993, tire manufacturers led by Michelin conducted studies using silica as a reinforcing agent in place of carbon black to reduce greenhouse gas emissions. Unlike hydrophobic carbon black, silica uses a silane coupling agent to improve the traction and rolling resistance of tire compounds due to its hydrophilic surface properties. It was an opportunity to introduce a functional group into the (polymer) chain.

Meanwhile, a tire is a vulcanized product filled with various additives including a reinforcing agent. For ease of processing in the manufacturing process, a large amount of processing oil such as TDAE (treated distillate aromatic extracts) oil is added as a processing aid. Since tires undergo large and small deformations at high temperatures during driving and braking, the injected processing oil gradually migrates and comes out of the compound as the driving distance and time increase. The compound from which the processing oil has escaped becomes hard and has worse properties than the initial properties. In particular, the tread hardened during braking is less deformed, so the contact area with the road surface is reduced and braking performance is deteriorated. In the case of liquid butadiene rubber, it is a processing aid and can form a cross-link with the rubber main chain of the compound during the vulcanization process. In addition, it is possible to control the compound glass transition temperature (T _g ) according to the microstructure of the liquid butadiene rubber, so that excellent snow braking performance and abrasion resistance can be obtained when a low T _g liquid butadiene rubber is applied.

However, due to the large hysteresis resulting from the chain ends of the liquid butadiene rubber, the rolling resistance, which affects fuel efficiency, is disadvantageous. Therefore, in order to improve this, there is a need for a liquid butadiene rubber synthesis technology capable of chemically fixing the chain ends to the filler.

Republic of Korea Patent Publication No. 10-2008-0092378 (published on October 15, 2008)

An object of the present invention is a rubber composition for tire manufacturing using a liquid butadiene compound having both ends modified so that the chain ends can be chemically fixed to a filler in order to impart characteristics such as excellent fuel efficiency and wear performance to the tire, and tire manufacturing using the same to provide a way.

In order to achieve the above object, the present invention is a rubber polymer; and a compound represented by the following formula (1) as an active ingredient.

<Formula 1>

R' _x (RO) _3-x ㅡSiㅡ(CH ₂ ) _a ㅡS _c -(M)-S _d ㅡ(CH ₂ ) _b ㅡSiㅡ(OR) _3-x R' _x

In Formula 1, R and R' may each be the same or different, and are selected from hydrogen or (C1-C6) alkyl, x is an integer selected from 0 to 2, and a and b are each independently 1 to 5 is an integer selected from, c and d are each independently an integer selected from 1 to 9, and M is a polymer chain including one or two or more diene monomers.

M may be one or two or more selected from compounds represented by Formula 2-1, 2-2, or 2-3, and the compound represented by Formula 2-1 is 20 to 25 mol%, and Formula 2 The compound represented by -2 and 2-3 may be composed of 75 to 80 mol%, and may have a number average molecular weight of 500 to 50,000 g/mol.

<Formula 2-1>

<Formula 2-2>

<Formula 2-3>

M is butadiene, styrene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 2-phenyl-1,3-butadiene, 3-methyl One selected from the group consisting of -1,3-pentadiene, 2-chloro-1,3-butadiene, 3-butyl-1,3-octadiene, octadiene, acrylate-based monomers and acrylonitrile-based monomers; or It may be a copolymer of two or more monomers.

The compound may be a butadiene rubber modified at both ends.

The compound may have a vinyl (vinyl) content of 15 to 30 parts by weight based on 100 parts by weight of the total compound, and 1 to 3 functional groups of a silyl group may be included per one compound.

The rubber polymer is natural rubber; at least one butadiene rubber selected from the group consisting of butadiene rubber, styrene-butadiene rubber and nitrile rubber; or a mixture of these rubbers.

The compound may be included in an amount of 5 to 50 parts by weight based on 100 parts by weight of the rubber polymer.

The present invention provides a tire manufactured including the rubber composition for a tire.

The tire may further include one or two or more selected from the group consisting of silica, a coupling agent, a softener, a vulcanizing agent, a vulcanization accelerator, a crosslinking agent, a crosslinking activator, an antioxidant, an accelerator, and a super accelerator.

In addition, the present invention provides a first step of preparing a rubber mixture by mixing the rubber composition for a tire and silica; a second step of molding the prepared rubber mixture into a tire shape; and a third step of heating the rubber mixture in the form of the tire to perform a vulcanization reaction.

The rubber polymer is natural rubber; at least one butadiene rubber selected from the group consisting of butadiene rubber, styrene-butadiene rubber and nitrile rubber; or a mixture of these rubbers.

The rubber polymer may be a mixture of butadiene rubber and styrene-butadiene rubber in a weight ratio of 1: (3 to 5).

The rubber composition for a tire according to the present invention is a liquid butadiene modified at both ends using a chain transfer agent having a triethoxysilyl functional group and a tetra sulfide functional group and a 1,3-butadiene monomer By including the rubber, it is possible to improve fuel efficiency, prevent deterioration of physical properties due to changes over time, and lower the glass transition temperature (T _g ) of the liquid butadiene rubber to improve abrasion resistance.

1 shows a process for preparing a compound according to an embodiment of the present invention.
2 is a graph showing ¹ H-NMR results of Compound A prepared according to Example 1-1 of the present invention.
3 is a graph showing ¹ H-NMR results of Compound B prepared according to Example 1-2 of the present invention.
4 is a graph showing ¹ H-NMR results of Compound C prepared according to Examples 1-3 of the present invention.
5 is a graph showing ¹ H-NMR results of Compound D prepared according to Examples 1-4 of the present invention.
6 is a graph showing ¹ H-NMR results of Compound E prepared according to Examples 1-5 of the present invention.
7 is a graph showing ¹ H-NMR results of Compound F prepared according to Examples 1-6 of the present invention.
8 is a graph showing the results of size exclusion chromatography (SEC) analysis of compounds C, D, E, and F prepared according to Examples 1-3 to 1-6 of the present invention.

Hereinafter, the present invention will be described in detail.

The terms used in the present invention have been selected as currently widely used general terms as possible while considering the functions in the present invention, but these may vary depending on the intention or precedent of a person skilled in the art, the emergence of new technology, and the like. Therefore, the term used in the present invention should be defined based on the meaning of the term and the overall content of the present invention, rather than the name of a simple term.

In the entire specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

The present invention relates to a rubber polymer; and a compound represented by the following formula (1) as an active ingredient.

<Formula 1>

R' _x (RO) _3-x ㅡSiㅡ(CH ₂ ) _a ㅡS _c -(M)-S _d ㅡ(CH ₂ ) _b ㅡSiㅡ(OR) _3-x R' _x

In Formula 1, R and R' may each be the same or different, and are selected from hydrogen or (C1-C6) alkyl, x is an integer selected from 0 to 2, and a and b are each independently 1 to 5 is an integer selected from, c and d are each independently an integer selected from 1 to 9, and M is a polymer chain including one or two or more diene monomers.

Preferably, M may be one or two or more selected from compounds represented by the following Chemical Formulas 2-1, 2-2, or 2-3.

<Formula 2-1>

<Formula 2-2>

<Formula 2-3>

Preferably, M is 20 to 25 mol% of the compound represented by Formula 2-1, and 75 to 80 mol% of the compound represented by Formulas 2-2 and 2-3, but is limited thereto it's not going to be

Preferably, M may have a number average molecular weight of 500 to 50,000 g/mol, more preferably 1000 to 10,000 g/mol, but is not limited thereto.

Alternatively, M is butadiene, styrene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 2-phenyl-1,3-butadiene, 3 -methyl-1,3-pentadiene, 2-chloro-1,3-butadiene, 3-butyl-1,3-octadiene, octadiene, acrylate-based monomers and acrylonitrile-based monomers selected from the group consisting of It may be one or a copolymer of two or more monomers, but is not limited thereto.

The compound according to the present invention may include a unit structure derived from M, and is preferably a butadiene polymer, that is, butadiene rubber modified at both ends, but is not limited thereto.

The both-end modified butadiene rubber has a very small molecular weight compared to conventional solid butadiene and is in a liquid state at room temperature, and thus can be used as a processing aid for smooth mixing of rubber and silica like process oil.

Preferably, the compound may have a vinyl (vinyl) content of 15 to 30 parts by weight, more preferably 18 to 25 parts by weight, based on 100 parts by weight of the total compound, but is not limited thereto.

Preferably, the compound may include 1 to 3 functional groups of a silyl group per one compound, but is not limited thereto.

The rubber polymer is natural rubber; at least one butadiene rubber selected from the group consisting of butadiene rubber, styrene-butadiene rubber and nitrile rubber; or a mixture of these rubbers.

The present invention is the rubber polymer; and a compound represented by the following formula (1) as an active ingredient.

More specifically, the tire may be manufactured by crosslinking the compound with the rubber polymer and the silica.

The rubber polymer is natural rubber; at least one butadiene rubber selected from the group consisting of butadiene rubber, styrene-butadiene rubber and nitrile rubber; or a mixture of these rubbers.

Preferably, the rubber polymer may include solution polymerization styrene-butadiene prepared by a continuous method of styrene and butadiene, wherein the styrene is 20 to 30 parts by weight based on 100 parts by weight of the total styrene-butadiene. The butadiene may have a vinyl content of 20 to 30 parts by weight based on 100 parts by weight of the total butadiene, but is not limited thereto.

Preferably, the rubber polymer may include a solution polymerization butadiene rubber prepared by a neodymium catalyst, having a cis content of 90% by weight or more, which has excellent abrasion resistance performance due to the high cis content.

Preferably, the rubber polymer may be a mixture of the butadiene rubber and the styrene-butadiene rubber in a weight ratio of 1: (3 to 5), but is not limited thereto.

The silica may be included in an amount of 90 to 130 parts by weight, preferably 110 to 120 parts by weight, based on 100 parts by weight of the rubber polymer. When the content of silica is less than 90 parts by weight based on 100 parts by weight of the rubber polymer, braking performance on a wet road surface may be reduced due to a decrease in the silica content, and when it exceeds 130 parts by weight, the amount of silica is large and processing during mixing This can be difficult, so this range is preferred.

Preferably, the silica may be precipitated silica having a CTAB surface area of 180 m ² /g to 220 m ² /g. In this case, dispersion is easy, which is advantageous for improving wear resistance and further improving braking performance on a wet road surface.

The compound may be included in an amount of 5 to 50 parts by weight based on 100 parts by weight of the rubber polymer. When the compound is less than 5 parts by weight based on 100 parts by weight of the rubber polymer, mixing of the rubber polymer and silica may not be performed smoothly, and the effect of improving wear and fuel efficiency may not be large. In addition, when the content of the compound exceeds 50 parts by weight based on 100 parts by weight of the rubber polymer, the glass transition temperature of the tire is greatly reduced, which may adversely affect braking performance on a wet road surface.

The tire may be manufactured by further comprising one or two or more selected from the group consisting of a coupling agent, a softener, a vulcanizing agent, a vulcanization accelerator, a crosslinking agent, a crosslinking activator, an antioxidant, an accelerator, and a super accelerator, but is not limited thereto not.

Preferably, the vulcanizing agent may include a sulfur vulcanizing agent. As the sulfur vulcanizing agent, elemental sulfur or a sulfur-producing vulcanizing agent, for example, amine disulfide or polymeric sulfur may be used, and elemental sulfur may be preferably used.

The vulcanizing agent may be used in an amount of 1.0 to 1.5 parts by weight based on 100 parts by weight of the rubber polymer, and it is preferable because it can make the rubber less sensitive to heat and chemically stable as an appropriate vulcanization effect within the above range.

In addition, as the vulcanization accelerator, amine, disulfide, guanidine, thio, urea, thiazole, thiuram, sulfene amide, and combinations thereof One selected from the group may be further included in an amount of 1.0 to 3.0 parts by weight based on 100 parts by weight of the rubber polymer.

The tire is an antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N-phenyl-N'-isopropyl-p-phenylenediamine, N,N 100 weight of the rubber polymer, any one selected from the group consisting of '-diphenyl-p-phenylenediamine (3PPD), 2,2,4-trimethyl-1,2-dihydroquinoline (RD), and combinations thereof It may be further included in an amount of 1 to 5 parts by weight based on parts.

It goes without saying that, in addition to the tire, various additives such as zinc oxide, stearic acid, a coupling agent or a processing aid used in the manufacture of tires may be selected and used as needed.

The tire according to the present invention may be a passenger car tire, a racing tire, an airplane tire, an agricultural machine tire, an off-the-road tire, a truck tire, or a bus tire, but is not limited thereto.

In addition, the tire may be a radial tire or a bias tire, preferably a radial tire.

The present invention is the rubber polymer; and a compound represented by the following formula (1); a rubber composition for a tire comprising as an active ingredient; and a first step of preparing a rubber mixture by mixing silica; a second step of molding the prepared rubber mixture into a tire shape; and a third step of heating the rubber mixture in the form of the tire to perform a vulcanization reaction.

Corresponding features may be substituted for the above-mentioned parts.

In the tire manufacturing method according to the present invention, the first step of preparing the rubber mixture may be performed by further including a conventional process oil, but is not limited thereto.

The compound may be added to replace some or all of the conventional process oil with a processing aid, and preferably, the compound may replace a part of the oil, so that the compound and the process oil may be included at the same time.

As described above, when the tire is manufactured, by using the rubber composition for a tire containing the compound, it is possible to significantly improve fuel efficiency and wear performance and prevent deterioration of physical properties due to changes over time.

In addition, the present invention provides a rubber composition comprising a compound represented by the following formula (1) as an active ingredient.

<Formula 1>

R' _x (RO) _3-x ㅡSiㅡ(CH ₂ ) _a ㅡS _c -(M)-S _d ㅡ(CH ₂ ) _b ㅡSiㅡ(OR) _3-x R' _x

In Formula 1, R and R' may be the same or different, respectively, and are selected from hydrogen or (C1-C6) alkyl, x is an integer selected from 0 to 2, and a and b are each independently 1 to 5 is an integer selected from, c and d are each independently an integer selected from 1 to 9, and M is a polymer chain including one or two or more diene monomers.

The rubber composition may further include one or two or more selected from the group consisting of natural rubber, synthetic rubber, coupling agent, softener, vulcanizing agent, vulcanization accelerator, crosslinking agent, crosslinking activator, antioxidant, accelerator and super accelerator. .

The rubber composition may be used for the manufacture of tires, profiles, cable sheaths, hoses, drive belts, conveyor belts, tire treads, shoe soles, sealing rings or damping elements.

Corresponding features may be substituted for the above-mentioned parts.

Hereinafter, to help the understanding of the present invention, examples will be described in detail. However, the following examples are merely 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 of ordinary skill in the art.

<Example 1> Preparation of compound (both end-modified liquid butadiene)

1. Material

Cyclohexane (99%, Samchun Chemical Co., Seoul, South Korea), bis-[3-(triethoxysilyl)propyl]tetrasulfide (Bis-[3-(triethoxysilyl)propyl]tetrasulfide, TESPT, Si -69, Evonik Korea Ltd., Korea) and di-tert-butyl peroxide (Sigma-Aldrich Corp., Seoul, Korea) were prepared.

2. Synthesis

At room temperature, TESPT (Si-69), di-tert-butyl peroxide (I), and cyclohexane were added to a high-temperature and high-pressure stirred reactor (1L) made of stainless steel, respectively, and then replaced with nitrogen. 1,3-butadiene (monomer) (BD) was injected through the gas line of the reactor. Then, the temperature was raised to 135° C., and polymerization was carried out for a corresponding time under a specific pressure. Thereafter, the reaction was terminated by lowering the temperature to 15° C., and after reaching 15° C., unreacted 1,3-butadiene was removed through a vent line. In the case of cyclohexane, it was removed by vacuum distillation. The remaining initiator and chain transfer agent were removed using a centrifugal separator after the polymer was precipitated in ethanol (FIG. 1).

<Example 1-1> Preparation of compound A

By the method of Example 1, TESPT 18g, di-tert-butyl peroxide 0.49g, cyclohexane 180g, 1,3-butadiene 180g, polymerization was carried out at 18 bar pressure for 4 hours to prepare Compound A.

<Example 1-2> Preparation of compound B

By the method of Example 1, TESPT 9g, di-tert-butyl peroxide 0.49g, cyclohexane 180g, 1,3-butadiene 180g, polymerization was carried out at 18 bar pressure for 4 hours to prepare Compound B.

<Example 1-3> Preparation of compound C

By the method of Example 1, TESPT 9g, di-tert-butyl peroxide 0.49g, cyclohexane 180g, 1,3-butadiene 180g, polymerization was carried out at 40 bar pressure for 4 hours to prepare Compound C.

<Example 1-4> Preparation of compound D

By the method of Example 1, TESPT 9g, di-tert-butyl peroxide 0.49g, cyclohexane 180g, 1,3-butadiene 180g, polymerization was carried out at 40 bar pressure for 8 hours to prepare Compound D.

<Example 1-5> Preparation of compound E

In the method of Example 1, using TESPT 21.6 g, di-tert-butyl peroxide 0.73 g, cyclohexane 180 g, 1,3-butadiene 180 g, polymerization was carried out at 40 bar pressure for 8 hours to prepare Compound E .

<Example 1-6> Preparation of compound F

By the method of Example 1, TESPT 18g, di-tert-butyl peroxide 0.97g, cyclohexane 180g, 1,3-butadiene 180g, polymerization was carried out at 40 bar pressure for 8 hours to prepare Compound F.

<Experimental Example 1> Analysis of the physical properties of the compound

1-1. Analysis method

1) Molecular weight analysis

Solvent delivery unit, refractive index detector and 3 types of styragel column [HT 6E (10μm, 7.8 mm × 300 mm), HMW 7 column (15-20μm, 7.8 mm × 300 mm), HMW 6E column (15-20 μm, 7.8 mm × 300 mm)] was used for size exclusion chromatography (SEC), a polybutadiene standard sample (Waters Corp., Germany) was used for molecular weight correction.

2) Check the vinyl content

Vinyl content in the compound prepared according to Example 1 using Proton nuclear magnetic resonance ( ¹ H NMR, Varian, Unity Plus 300 spectrometer, Garden State Scientific, Morristown, NJ, USA) was confirmed. The compound was dissolved in deuterochloroform (CDCl ₃ , Cambridge Isotope Laboratories, Inc., Andover, MA, USA) as a solvent in a 5 mm NMR tube at a concentration of 15 mg/mL.

3) Glass transition temperature (T _g ) Confirm

The glass transition temperature (T _g ) of the compound was measured using a differential scanning calorimetry (DSC), and a differential scanning calorimeter (DSC-Q10, TA Instruments, New Castle, DE, USA). Thermograms for the samples (3 - 6 mg) were obtained by heating the sample from -120°C to -20°C under a nitrogen atmosphere at a heating rate of 10°C per minute.

1-2. Analysis

When the degree of polymerization (D _p ) of liquid butadiene (LqBR) is 100 or less, it exists in a viscous liquid state at room temperature, and depending on their chain length and microstructure properties are different. Therefore, in this experiment, it was attempted to synthesize the molecular weight of both terminal modified liquid butadiene (DF-LqBR) with D _p ≤ 100.

Table 1 below shows the physical properties of the compound prepared according to Example 1.

Item compound A
(Example 1-1) compound B
(Example 1-2) compound C
(Example 1-3) compound D
(Examples 1-4) compound E
(Example 1-5) compound F
(Example 1-6) [I]:[Si-69]:[BD] 1:5:1000 1:10:1000 1:10:1000 1:10:1000 1.5:12:1000 2:10:1000 reaction time 4 4 4 8 8 8 pressure 18 bar 18 bar 40 bar 40 bar 40 bar 40 bar Molecular Weight
(Mn, g/mol)
3,800
5,900
3,460
5,070
4,570
5,230 molecular weight distribution
(Mw/Mn)
2.16
2.88
2.45
3.06
2.84
2.90 vinyl content
(weight%)
20
21
22
22
22
22 glass transition temperature
(℃)
-84.0
-82.8
-85.6
-94.1
-88.5
-83.4 Functionality
(Si/Chain)
2.1
1.92
2.33
2.10
2.02
1.92

* I: Initiator / Si-69: Chain transfer agent (TESPT) / BD: Butadiene monomer

<Example 2> Preparation of rubber composition

Table 2 below shows the composition of each material for preparing the rubber composition for a tire tread including the compounds A-F prepared according to Example 1 above.

(unit:
parts by weight)
Comparative Example 1
Comparative Example 2 rubber
composition A rubber
composition B rubber
composition C rubber
composition D rubber
composition E rubber
composition F S-SBR ¹⁾ 80 80 80 80 80 80 80 80 BR ²⁾ 20 20 20 20 20 20 20 20 silica ³⁾ 120 120 120 120 120 120 120 120 coupling agent ⁴⁾ 20 20 20 20 20 20 20 20 Softener ⁵⁾ 40 30 30 30 30 30 30 30 Comparative Example 2 ⁶⁾ - 10 - - - - - - compound A - - 10 - - - - - compound B - - - 10 - - - - compound C - - - - 10 - - - compound D - - - - - 10 - - compound E - - - - - - 10 - compound F - - - - - - - 10 zinc oxide ⁷⁾ 3 3 3 3 3 3 3 3 stearic acid ⁸⁾ One One One One One One One One antioxidants ⁹⁾ 2 2 2 2 2 2 2 2 sulfur ¹⁰⁾ 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 CBS ¹¹⁾ 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 DPG ¹²⁾ 2 2 2 2 2 2 2 2 ZBEC ¹³⁾ 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2

Details of the substances included in Table 2 are as follows.

1) S-SBR (Solution-Styrene Butadiene Rubber) has a styrene content of 26.5% by weight, a vinyl content of 26% by weight in butadiene, a Mooney viscosity of 54, and a glass transition temperature of -48 ℃, manufactured by a continuous method. solution polymerization styrene-butadiene rubber (5220M, Kumho Petrochemical Co., Ltd., Korea).

2) BR is solution polymerization butadiene rubber (CB24, Lanxess Chemical Industry Co., Ltd., Cologne, Germany) having a cis content of 96% by weight in butadiene, a Mooney viscosity of 44, and prepared by a neodymium catalyst.

3) Silica is cetyl trimethyl ammonium bromide (CTAB) micropearl type precipitated silica (ZEOSIL 195MP, Solvay Silica Korea Co., Ltd.) having a surface area of 180 m ² /g to 220 m ² /g ., Gunsan, Korea) were used.

4) The coupling agent contains 50 wt% of bis-[3-(triethoxysilyl)propyl]tetrasulfide (Bis-[3-(triethoxysilyl)propyl]tetrasulfide, TESPT) and 50 wt% of carbon black N330 %, the trade name is X50S (Evonik Industries AG, Essen, Germany).

5) As a softener (process oil), the total content of polycyclic aromatic hydrocarbon (PAH) components is 3% by weight or less, the kinematic viscosity is 95 (210°F SUS), and the aromatic component in the softener is 25% by weight, naphthenic components TDAE (treated distilled aromatic extracted) oil (Vivatec 500, Kukdong Oil & Chemicals Co., Yangsan, Korea) containing 32.5 wt% of this 32.5 wt% and 47.5 wt% of a paraffinic component was used.

6) Comparative Example 2 is an unmodified liquid butadiene rubber, specifically, a liquid polybutadiene rubber (LBR 307, Kuraray, Japan).

7) Zinc oxide as a crosslinking activator, Zinc oxide No. 2 (Sigma-Aldrich Corp., Seoul, Korea) was used.

8) Stearic acid was used as a crosslinking activator (Sigma-Aldrich Corp., Seoul, Korea).

9) Antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine [N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 6PPD, Kumho Petrochemical Co., Daejeon, Korea] was used.

10) Sulfur as a crosslinking agent, sulfur powder (elemental sulfur, Daejung Chemicals & Metals Co., Siheung, Korea) was used.

11) CBS [N-cyclohexyl-2-benzothiazolylsulfenamide, 98%, Tokyo Chemical Industry Co. Ltd., Tokyo, Japan] was used as an accelerator.

12) DPG (1,3-Diphenylguanidine, 98%, Tokyo Chemical Industry Co. Ltd., Tokyo, Japan)

13) As a super accelerator, zinc dibenzyl dithiocarbamate (ZBEC; Sigma-Aldrich Corp., Seoul, Korea) was used.

The rubber composition was prepared according to the method for preparing the rubber composition shown in Table 3 below.

step Time (minutes:seconds) Way





Stage 1 0:00-0:40 Rubber injection (initial temperature: 100℃) 0:40-1:20 mix 1:20-2:20 Silica 1/2 + X50S 1/2 +DPG 1/2 + Oil 1/2
+ Add 1/2 compound 2:20-3:20 mix 3:20-4:20 Silica 1/2 + X50S 1/2 +DPG 1/2 + Oil 1/2
+ Add 1/2 compound 4:20-5:20 mix 5:20-5:40 Addition of ZnO, St/A, 6PPD 5:40-8:00 mix 8:00-9:00 Ram up 9:00-11:40 Additional mixing and dump (dump temperature: 150-155℃)

Step 2 0:00-0:40 Add masterbatch in step 1 (initial temperature: 50℃) 0:40-1:00 mix 1:00-1:20 Add curatives 1:20-3:00 Mix and dump (dump temperature: 80-90℃)

As shown in Table 3, the rubber composition for the tire tread was manufactured through a two-step continuous manufacturing process. That is, less than 110° C. during the first step of thermomechanical treatment or kneading (non-production step) and the finishing step in which the crosslinking system is mixed at a maximum temperature of 100° C. to 180° C., preferably at a high temperature of 130° C. to 160° C. , for example, in a suitable mixer using a second stage (production stage) of mechanical treatment at a low temperature of 40°C to 100°C.

<Experimental Example 2> Analysis of physical properties of rubber composition

2-1. Analysis method

1) Mooney viscosity (ML1+4@100℃)

According to ASTM D-1646, it was measured with a Mooney viscometer (Vluchem IND Co., Korea).

2) Mechanical properties

According to ASTM D412, using a universal testing machine (Universal testing machine, UTM, KSU-05M-C, KSU Co., Korea), the modulus at 100% elongation (modulus, M100%), the modulus at 300% elongation (M300) %) and elongation were measured.

3) Wear-resistant performance

A cylindrical specimen having a diameter of 16 mm and a thickness of 8 mm was prepared according to DIN 53516. The specimen was polished by 40 m at a speed of 40 rpm using a German industrial standard (Deutsche Industrie Normen, DIN) abrasion tester to measure the amount of mass reduction.

4) dynamic viscoelasticity

A temperature sweep was performed using an ARES meter with 0.5% strain, -60°C to 70°C storage modulus (G'), loss modulus G" at a frequency of 10 Hz. , tan δ were measured in torsion mode.

The strain sweep was performed using a dynamic material thermal spectrometer (DMTS, Eplexor 500N, GABO GmbH & Co. KG, Germany) at a temperature of 60 °C and a frequency of 10 Hz from a dynamic strain of 0.5% to Measured in tension mode up to 10%.

2-2. Analysis

Table 4 below shows the results of analyzing the physical properties of the rubber composition according to Experimental Example 2.

Item Comparative Example 1 Comparative Example 2 rubber
composition A rubber
composition B rubber
composition C rubber
composition D rubber
composition E rubber
composition F Payne effect
(ΔG′,MPa)
7.36
6.84
5.39
5.65
4.16
5.57
5.94
5.93 Mooney viscosity
(ML ₁₊₄ @100℃)
154
152
139
148
117
134
140
142 Extraction weight reduction (%)
: value for the replaced 10phr
100
84
One
2
8
10
5
3 Total crosslink density
(Total crosslink density; Filler-rubber interaction + chemical crosslink density,
10 ^-4 mol/g)



1.45



1.34



1.65



1.57



1.59



1.66



1.64



1.62 filler - rubber
Interaction
(Filler-rubber interaction,
10 ^-4 mol/g)

1.01

0.94

1.16

-

-

-

1.15

1.15 chemical crosslinking density
(Chemical crosslink density,
10 ^-4 mol/g)

0.44

0.40

0.49

-

-

-

0.49

0.47 30% modulus
(kgf/cm ² )
19.3
18.7
23.4
22.7
22.0
22.2
21.6
22.1 300% modulus
(kgf/cm ² )
173
145
166
176
161
170
167
166 DIN abrasion (mg) (Index)
110
(100)
99
(110)
96
(113)
103
(106)
97
(112)
99
(110)
100
(109)
99
(110) Glass transition temperature (℃) -38.8 -42.5 -40.0 -40.5 -40.9 -41.6 -41.6 -41.9 G’ at -30℃, MPa (Index) 170
(100) 142
(116) 146
(114) 153
(110) 157
(108) 155
(109) 161
(105) 156
(108) G” at 0℃, MPa (Index) 11.4
(100) 10.5
(92) 9.9
(87) 10.2
(89) 11.1
(96) 11.0
(96) 10.9
(96) 10.9
(96) Tan δ at 60℃
(Index) 0.177
(100) 0.181
(98) 0.170
(104) 0.169
(105) 0.168
(105) 0.171
(103) 0.171
(103) 0.173
(102)

Referring to Table 4, the Payne effect represents the filler-filler interaction of the unvulcanized material. The decrease in the storage modulus (G') according to the increase in the strain amplitude is a result of the breakdown of the filler network, and the larger the ΔG' value, the stronger the filler-filler interaction. The compound prepared according to Example 1 showed a low Payne effect value as silica dispersion was improved by hydrophobizing the silica surface.

Mooney viscosity is an indicator of compound processability, and the compound not only improved silica dispersion but also acted as a lubricant between raw rubber, thereby reducing the Mooney viscosity of the rubber composition as chain slippage occurred well.

The extraction weight loss value is an experimental result that can predict the migration of the processing aid from the vulcanizate. The lower the value, the higher the extraction resistance.

The compound prepared according to Example 1 may be fixed to the rubber network through co-vulcanization with raw rubber during vulcanization, and functional groups at the ends may be fixed to the silica surface through silanization reaction. Compared to Comparative Example 1, the extraction amount was small. That is, it is possible to prevent the deterioration of the physical properties due to the change over time by reducing the migration phenomenon.

The total crosslink density is defined as the number of crosslink points in the vulcanizate. A high crosslinking density means that the molecular weight between crosslinking points decreases and the number of crosslinking points increases. In the swelling test, the higher the crosslink density, the less the number of solvent molecules that can penetrate between the crosslinked rubber chains, so that swelling occurs less.

In the compound prepared according to Example 1, a three-dimensional network structure formed through a self-condensation reaction has swelling resistance, so that compared to Comparative Examples 1 and 2, a higher chemical crosslink density (chemical crosslink density) was shown. In addition, filler-rubber interaction may be increased due to the coupling reaction with the raw rubber by -Si-. As a result, the total crosslinking density was higher than Comparative Examples 1 and 2.

The compound formed a three-dimensional-network structure through a self-condensation reaction, and increased the initial modulus (30% modulus) in the low elongation region compared to Comparative Example 1.

The compound exhibited a 300% modulus value higher than that of Comparative Example 2 by increasing filler-rubber interaction through a coupling reaction by -Si-.

Abrasion resistance is greatly affected by the glass transition temperature (T _g ) of the rubber and the filler-rubber interaction.

The compound prepared according to Example 1 not only lowered the glass transition temperature of the rubber composition, but also improved the abrasion resistance performance by increasing filler-rubber interaction through a coupling reaction by -Si-.

The viscoelastic properties of rubber compositions are laboratory measurements that can predict tire performance, and the correlation between the two is very high. The storage modulus (G') value at -30°C in Table 4 is an index indicating snow traction on an icy and snowy road surface, and the lower the value, the better the snow traction. This is because the tire tread is easily deformed on the icy road surface and the contact area can be increased as it has a lower G' value in the low temperature condition.

The loss modulus (G″) at 0° C., which is used as an index of the wet traction of the tire on a wet road surface, is the higher the value, the better the wet traction performance. And the G″ value is higher as the effective filler volume fraction is higher. The tan δ value at 60° C. is an index indicating the rolling resistance (RR) of a tire, and it is known that the lower the value, the better the fuel economy performance. It is known that the main energy dissipation at this temperature is due to the breakage and regeneration of the filler-filler network and the free chain ends of the rubber.

The compound has a lower glass transition temperature (T _g ) than process oil, thereby lowering the glass transition temperature of the rubber composition, thereby reducing the flexibility and modulus of the rubber at low temperatures, thereby greatly improving the braking performance (snow traction) on icy and snowy road surfaces. can

The compound lowers the glass transition temperature of the rubber composition, and as the silica dispersion is improved, the effective filler volume fraction is lowered, so that the G″ value at 0°C is lower than that of the rubber composition to which the process oil is applied (Comparative Example 1). can represent

Since the compound has less hysteresis due to a decrease in the number of free chain ends as the ends are fixed to the silica surface, the rubber composition to which the process oil is applied (Comparative Example 1) and the rubber composition to which the unmodified liquid butadiene rubber is applied (Comparative Example 2) Fuel efficiency characteristics may be improved.

Therefore, referring to the results of Table 4, the rubber compositions for tire treads prepared in the Examples include both ends modified liquid butadiene rubber, which is the compound, thereby improving wear performance and fuel economy performance at the same time while changing over time. It is possible to prevent deterioration of properties. Accordingly, it can be seen that the compound can be used as a rubber composition for a tire tread.

As the specific parts of the present invention have been described in detail above, for those of ordinary skill in the art, these specific descriptions are only preferred embodiments, and it is clear that the scope of the present invention is not limited thereto. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents. The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention.

Claims (15)

rubber polymers; and
A rubber composition for a tire comprising a compound represented by the following formula (1) as an active ingredient:
<Formula 1>
R' _x (RO) _3-x —Si—(CH ₂ ) _a —S _c -(M)—S _d —(CH ₂ ) _b —Si—(OR) _3-x R’ _x
In Formula 1,
R and R' can each be the same or different and are selected from hydrogen or (C1-C6) alkyl,
x is an integer selected from 0 to 2,
a and b are each independently an integer selected from 1 to 5,
c and d are each independently an integer selected from 1 to 9,
M is a polymeric chain comprising one or more diene monomers.
The method of claim 1,
wherein M is,
A rubber composition for a tire, characterized in that at least one selected from the compounds represented by the following Chemical Formulas 2-1, 2-2, or 2-3.
<Formula 2-1>

<Formula 2-2>

<Formula 2-3>

3. The method of claim 2,
wherein M is,
20 to 25 mol% of the compound represented by Formula 2-1,
The rubber composition for a tire, characterized in that 75 to 80 mol% of the compound represented by Formulas 2-2 and 2-3.
The method of claim 1,
wherein M is,
A rubber composition for a tire, characterized in that the number average molecular weight is 500 to 50,000 g/mol.
The method of claim 1,
wherein M is,
butadiene, styrene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 2-phenyl-1,3-butadiene, 3-methyl-1, One or two or more monomers selected from the group consisting of 3-pentadiene, 2-chloro-1,3-butadiene, 3-butyl-1,3-octadiene, octadiene, acrylate-based monomers and acrylonitrile-based monomers A rubber composition for tires, characterized in that it is a copolymer of
The method of claim 1,
The compound is
A rubber composition for a tire, characterized in that both ends are modified butadiene rubber.
The method of claim 1,
The compound is
Based on 100 parts by weight of the total compound, the rubber composition for a tire, characterized in that the vinyl (vinyl) content is 15 to 30 parts by weight.
The method of claim 1,
The compound is
A rubber composition for a tire, characterized in that 1 to 3 functional groups of a silyl group are included per one compound.
The method of claim 1,
The rubber polymer is
caoutchouc; at least one butadiene rubber selected from the group consisting of butadiene rubber, styrene-butadiene rubber and nitrile rubber; Or a rubber composition for a tire, characterized in that it is selected from these mixed rubbers.
The method of claim 1,
The compound is
Based on 100 parts by weight of the rubber polymer, 5 to 50 parts by weight of the rubber composition for a tire is included.
A tire manufactured including the rubber composition for a tire according to any one of claims 1 to 10.
12. The method of claim 11,
The tire is
A tire, characterized in that it further comprises one or two or more selected from the group consisting of silica, a coupling agent, a softener, a vulcanizing agent, a vulcanization accelerator, a crosslinking agent, a crosslinking activator, an antioxidant, an accelerator and a super accelerator.
A first step of preparing a rubber mixture by mixing the rubber composition for a tire according to any one of claims 1 to 10 and silica;
a second step of molding the prepared rubber mixture into a tire shape; and
and a third step of heating the rubber mixture in the form of the tire to perform a vulcanization reaction.
14. The method of claim 13,
The rubber polymer is
caoutchouc; at least one butadiene rubber selected from the group consisting of butadiene rubber, styrene-butadiene rubber and nitrile rubber; Or a method for manufacturing a tire, characterized in that it is selected from mixed rubbers thereof.
14. The method of claim 13,
The rubber polymer is
A method of manufacturing a tire, characterized in that a butadiene rubber and a styrene-butadiene rubber are mixed in a weight ratio of 1: (3 to 5).

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