KR20120099874A - Styrene-butadiene copolymers, process for the preparation thereof and ultra high performance tire using thereof - Google Patents

Abstract

PURPOSE: A styrene-butadiene copolymer is provided to have excellent silica processability, and to have excellent combination of rolling resistance and friction to wet surface. CONSTITUTION: A styrene-butadiene copolymer comprises a reaction product of continuous solution polymerization from butadiene-based monomer and styrene-based monomer. A Mooney viscosity of the copolymer in which processing oil is added is 57-67 ML(1+4)/100°C, styrene content is 23-27 weight%, vinyl content is 46-54%. The continuous solution polymerization is conducted under the presence of alkyl lithium(NBL) as a base catalyst of 0.01-0.05 phr, and a dibutyl magnesium as a sub catalyst of 0.005-0.25 phr.

Description

Styrene-Butadiene Copolymers, Process for the Preparation Thereof and ultra high performance Tire using Technical}

The present invention relates to a styrene-butadiene copolymer as a high-vinyl rubber-needle solution polymerization SBR, a method for preparing the same, and an energy-saving tire using the same. The use of elastomers of this kind in the manufacture of energy-saving tires offers the characteristics of excellent silica processability and a good balance of wear resistance, wet road friction and rolling resistance.

The invention also relates to a process for obtaining SBR copolymers, which simultaneously comprises continuous solution polymerization and maintaining a high range of Mooney viscosity and the combined styrene content and vinyl content of the copolymer. The invention further relates to an energy saving tire obtained from the SBR copolymer in solid form.

The tire efficiency rating system, which originated in Europe, is gradually affecting the tire industry worldwide, including the United States, Japan, and Korea. This is due to the significant increase in energy costs due to the shortage of fossil energy, which is limited in supply, and the seriousness of environmental problems such as global warming caused by air pollutants such as CO ₂ generated during energy consumption. This is because the fuel consumption rate (hereinafter referred to as fuel economy) and carbon dioxide emission standards for automobiles are greatly strengthened, starting with developed countries. In order to meet the stricter regulations on automobiles, tires, which have a significant impact on the energy consumption of automobiles, also require very strict fuel economy characteristics, while at the same time increasing the performance of automobiles and increasing the speed of roads is accompanied by an increase in vehicle speed. Therefore, in an emergency situation, the improvement of braking performance, especially braking performance on wet roads (hereinafter, required to have high wet grip properties and high wet road friction) has become an essential requirement of a tire.

Since tire grades, which have been recently evaluated in Europe for low fuel efficiency and braking performance, represent tire technology levels, each tire is made of synthetic rubber, especially UHP (Ultra High Performance), UHP ') is showing great interest in SSBR with high vinyl viscosity, which is a synthetic rubber that can be used for tires.

Synthetic rubber that is frequently used for energy-saving high-performance tires (UHP Tire) is High Vinyl High Mooney Type Solution Polymerization SBR (hereinafter referred to as HVHM-SSBR). However, the most important required properties of SSBR for UHP tires are not only LRR characteristics (low rolling resistance, which is evaluated as tan δ measured mainly at 60 ℃ by crosslinked rubber, smaller glass) but also during high-speed driving. Stopping resistance (Wet Grip, evaluated as tanδ measured mainly at 0 ° C with glass crosslinked rubber, is also important) is a very important property because safety can only be ensured if it can be stopped quickly on wet roads.

Here, one of the most basic characteristics traditionally required for tires is that the wear resistance should be excellent for a long time. In general, these three important properties are strongly mutually exclusive. When the tires have low rolling resistance and low energy loss due to friction, the wet road surface friction is also poor, and the braking characteristics are also low. On the contrary, when the wet road friction is excellent, the rolling resistance and wear resistance are poor. In order to improve such a double rate relationship, silica is often used instead of carbon black as a reinforcing agent in tire manufacture.Since silica has a lot of polarity factors on its surface, it has a strong self-aggregation and is difficult to mix well with a solution-polymerized SBR which is a nonpolar material. Due to its characteristics, various problems such as deterioration of workability due to poor dispersion (mainly sharply rise in Mooney viscosity after silica blending) or poor wearability have occurred.

In order to improve these problems, many SSBR manufacturers are producing products in which polar functional groups are given to polymer ends, but most of them are manufactured by batch polymerization method, which is economically burdened for use due to increased cost due to low productivity. On the other hand, SSBR manufactured by the continuous polymerization method has a high economical advantage, but has a disadvantage in that it is not easy to manufacture a product having affinity with silica. In consideration of these points, economic solution is considered by continuous solution polymerization method, and it also gives affinity with silica, so that the tire running resistance, wet road braking resistance and abrasion resistance are well balanced, and the appropriate molecular chain is given to add processing oil. It is intended to develop a high-vinyl solid-pattern solution polymerized SBR with good silica dispersion and processability without sacrificing the Mooney viscosity of the final rubber product.

Low fuel efficiency and wet road friction characteristics of tires include styrene monomer (hereinafter referred to as SM), vinyl content and molecular chain as macromolecular (hereinafter referred to as macrostructure) and microstructure (hereinafter referred to as microstructure) such as molecular weight, molecular weight distribution and branching of rubber polymers. Affinity with silica by a polar group group at the terminal is greatly influenced.

Rubber polymers having a large molecular weight and a linear molecular structure having a narrow molecular weight distribution are known to be advantageous in low fuel efficiency, but are difficult to disperse with reinforcing agents such as silica, resulting in poor dispersion and low fuel efficiency and wear resistance. Many problems, such as poor extrusion processability due to a sharp increase in the viscosity of the rubber compound may be adversely affected tire properties unless there is a special processing technology. Therefore, the rubber polymer for UHP tires should have an appropriate macrostructure in consideration of the appropriate molecular weight, molecular weight distribution, branching degree and affinity with silica.

On the other hand, even in the microstructure, increasing the styrene monomer content or vinyl content increases the glass transition temperature Tg (maximum point of tanδ, tanδ = G "/ G 'or E" / E', viscosity modulus / elastic modulus ratio) of the rubber polymer. It moves in a direction close to the tire's running range temperature (about 40 ~ 60 ℃), and tires made of rubber with high Tg increase energy loss due to increased hysteresis due to deformation during driving, which in turn hinders low fuel efficiency. Done. However, when the Tg is moved to a high temperature by increasing the vinyl content instead of increasing the styrene monomer content, it is advantageous in low fuel efficiency compared to the case in which the styrene monomer content is increased, and the low temperature performance in the winter or cold region is good. The reason for increasing the Tg in the high temperature direction is to maximize the hysteresis during braking by increasing the energy loss by braking the tire by placing the Tg in an area close to the tire resistance range of 0 to 20 ° C. That is, the reason for increasing the styrene monomer or vinyl content of the SSBR is the basic improvement of the stationary performance, and also considering the low fuel consumption performance, higher vinyl content than the styrene monomer is advantageous to the LRR (Low Rolling Resistance, low fuel efficiency) characteristics Vinyl SSBR was needed. SSBR, which is widely used in UHP tires, has a very high content of vinyl with a content of about 50% (50 ± 4% based on polymer) and a styrene monomer content of 25 ± 2%.

HVHM-SSBR is polymerized at a relatively low polymerization temperature (polymerized at 75 ° C. in the present invention) because the vinyl content is affected by the polymerization temperature, making it difficult to obtain a vinyl content of about 50% at the time of polymerization at a high temperature. On the other hand, in order to obtain a high Mooney viscosity SSBR of the polymer, it is necessary to reduce the input amount of the anion catalyst (mainly using NBL catalyst), but in this case, the reaction rate is slow and the polymerization rate is low due to the low reaction temperature and the small amount of catalyst. The high Mooney viscosity of the polymer is not easy to obtain.

In order to solve this problem, a method of obtaining a high molecular weight SSBR using a coupling agent capable of binding molecular-molecules to a low molecular weight SSBR polymer after first increasing the amount of NBL catalysts is commonly used. In this case, as the coupling agent, SiCl ₄ , SnCl ₄ , polysiloxane, or the like may be used. However, these commonly used coupling agents have an excessively high molecular weight relative to rubber Mooney Viscosity (MV), which may cause a decrease in workability when blended with silica. This negatively affects the characteristics required for UHP tires such as wear resistance and low fuel consumption. For example, when SiCl ₄ is used, the weight average molecular weight tends to be too large compared to the SSBR prepared using DBMg as the epoxy-based aniline and cocatalyst used in the present invention, compared to the final Mooney viscosity of the synthesized rubber. It's bad for sex. In the case of SnCl ₄ , since molecular chains are cut in the presence of an organic acid, there is a problem of causing continuous deterioration of physical properties after tire production.

Some SSBR manufacturers are making efforts to improve affinity with silica by end-modifying carboxyl groups, amino groups, alkoxysilyl groups, amine groups, siloxane groups, or epoxy groups at the end of the polymer. However, modified SSBR products containing such functional groups are mainly produced by batch polymerization method, which is disadvantageous in productivity, but only a few are known to be manufactured by continuous solution polymerization method.

On the other hand, high styrene SBR having a styrene content of more than 38% by weight has been mainly used for racing applications due to its high grip characteristics and high traction characteristics.

Suitable high styrene SBRs can be prepared by any synthetic method known in the art. These methods include both emulsification and solution polymerization methods as taught, for example, in US Pat. Nos. 6,372,863 and 6,455,655. Solution polymerized high styrene SBRs are described by Enenichem R74509; Goodyear X89137; Sumitomo SE8529; It is commercially available as Dow S LR 6610. Such high styrene SBRs will have a glass transition temperature (Tg) in the range of about −10 ° C. to about −25 ° C., indicated by the Tg midpoint for the non-oil extended polymer.

However, use for passenger cars, especially winter tires, has been limited because such tires must be used at relatively low temperatures below 0 ° C.

Accordingly, the inventors of the present invention have continued to earnest research, confirming the formulation of high-vinyl-rubber-needle-polymerized SBR excellent in silica processability and excellent in abrasion resistance, wet road friction and rotational resistance, and have completed the present invention.

That is, one object of the present invention is to provide a styrene-butadiene copolymer as a high-vinyl rubber solution polymerization SBR.

Another object of the present invention is to provide a method for obtaining an SBR copolymer which simultaneously comprises continuous solution polymerization and maintaining a high range of Mooney viscosity and the combined styrene content and vinyl content of the copolymer.

Another object of the present invention is to provide an energy saving tire obtained from the SBR copolymer in solid form.

According to the present invention,

It contains the reaction product of the continuous solution polymerization from styrene monomer and butadiene monomer, the oil viscosity of the oil-extended copolymer is in the range of 57 to 67 ML (1 + 4) / 100 ℃ And a styrene content of 23 to 27% by weight, and a vinyl content of 46 to 54% by weight based on the total rubber weight ratio, to provide a styrene-butadiene copolymer.

Furthermore, according to the present invention,

The process for obtaining the styrene-butadiene copolymers described above was carried out in a continuous solution polymerization at 73 to 77 DEG C, and an oily Mooney viscosity of 57 to 67 ML (1 + 4) / 100 DEG C, 23 to 27 wt% styrene content. And a content of 46 to 54% by weight of vinyl, and when applied to a silica standard compounding method, a method of preparing a styrene-butadiene copolymer, characterized in that the difference in the Mooney viscosity before and after compounding ( Δ MV) is 40 or less.

Furthermore, according to the present invention,

From about 40 to about 90 phr of the styrene-butadiene copolymer according to any one of claims 1 to 8, based on 100 parts by weight of an elastomer (phr); About 10 to about 60 phr of at least one additional elastomer; And about 10 to about 70 phr of a processing oil having a glass transition temperature of about -80 to about -40 ° C and a polycyclic aromatic content of less than 3% by weight as measured by the IP346 method. An energy saving tire is provided.

First, the formulation of the high-vinyl high Mooney viscosity solution SBR having excellent silica processability and excellent balance of wear resistance, wet road friction and rotational resistance according to the present invention will be described below.

The SBR provided by the present invention includes the reaction product of continuous solution polymerization, and has a Mooney viscosity of 57 to 67 ML (1 + 4) / 100 ° C. and a styrene content of the processing oil added copolymer. It is preferable that the copolymer is a copolymer having a vinyl content of 46 to 54% by weight based on the total rubber weight ratio, high vinyl concentration and high Mooney viscosity, and a glass transition temperature in the range of -40 to -20 ° C.

That is, the present invention includes styrene-butadiene rubber (SBR) of styrene in the vulcanizable rubber composition for tire manufacture. In one embodiment, the heavy styrene SBR has a styrene content of 23 to 27% by weight. In order to provide styrene SBR, dibutylmagnesium (hereinafter referred to as 'DBMg') was used as a co-catalyst together with an NBL catalyst, and a compound containing a divalent or trivalent epoxy functional group as a coupling agent. Ie, bis (2,3-epoxypropyl) aniline (hereinafter referred to as GAN) or N, N'-diglycidyl-4-glycidyloxyaniline (hereinafter referred to as DGGOA) as a coupling aid It is intended to provide an SSBR having silica affinity with SSBR of viscosity. In the case of SiCl ₄ , SnCl ₄ , and polysiloxane, which are commonly used coupling agents, the molecular weight is excessively increased compared to the rubber Mooney viscosity, which may cause workability deterioration when blended with silica, which may cause UHP such as wear resistance and low fuel consumption. This will have a negative impact on the characteristics required by the tire.

In addition, the continuous solution polymerization uses DBMg as an auxiliary catalyst together with alkyl lithium, such as n-butyllithium (NBL), as a main catalyst, so that the molecular chain is present and the weight average molecular weight is also relatively small, so that workability is advantageous. At this time, alkyl lithium as a main catalyst was formulated to satisfy the number average molecular weight (Mn) of 200,000 to 400,000 g / mole before coupling, which was final after coupling with the scavenger level such as monomer and water in the solvent. The weight average molecular weight (Mw) of the polymer is calculated by considering it to be in the range of 900,000 to 1.5 million g / mole.

In addition, the dibutyl magnesium (DBMg) is preferably used in 0.005 to 0.25 phr (part per hundred resin), preferably 0.01 to 0.1 phr, which also has a number average molecular weight (Mn) of 20 before the coupling It is calculated considering the balance with the NBL catalyst so as to satisfy the range of 10,000 to 400,000 g / mole.

In addition, the continuous solution polymerization is a divalent bis (2,3-epoxypropyl) aniline (GAN) containing an epoxy group or a coupling agent capable of appropriately increasing the molecular weight of the rubber while providing affinity between silica and rubber. Solution polymerization prepared using NBL as a catalyst and SiCl ₄ as a coupling agent by using a volatile N, N'-diglycidyl-4-glycidyloxyaniline (DGGOA) together with the cocatalyst (DBMg). Silica dispersibility and abrasion resistance, wet road surface braking ability is better than SBR, and the rotation resistance is not so much lowered. Therefore, the solution polymerization SBR with excellent balance of main characteristics required for UHP tires is made.

That is, in the present invention, by using a compound containing a divalent or trivalent epoxy functional group as the coupling agent, -OH groups having a polar group than the solution polymerization SBR using SiCl ₄ , which is a coupling agent generally used, can be provided in the polymer molecule. SSBR having excellent affinity with silica can be produced by a continuous solution polymerization method.

In this case, the bis (2,3-epoxypropyl) aniline (GAN) which is a coupling agent so that the number average molecular weight (Mn) of the polymer is in the range of 1.5 to 3.0 times, preferably 1.5 to 2.5 times after coupling, compared to before coupling. 0.20 phr (parts per hundred monomer), preferably 0.01 to 0.04 phr, and N, N'-diglycidyl-4-glycidyloxyaniline (DGGOA) is 0.01 to 0.30 phr, preferably 0.02 to 0.06 It is recommended to use within the phr range.

In addition, the continuous solution polymerization is performed by using ditetrahydrofuranylpropane (DTHFP) as a randomizing agent / vinyl content controlling agent in an amount of about 4.5 times the number of moles of the main catalyst NBL to obtain a polymer having a high vinyl content. It is preferable in terms of improving the stopping performance and rotational resistance. In terms of braking properties, if the styrene monomer content or vinyl content is increased, rubber hysteresis can be maximized to increase energy loss during braking, so that braking can be performed well. However, increasing vinyl content rather than styrene content can reduce the sacrifice of rotational resistance. In UHP tires, it is desirable to apply SBR with high vinyl content and relatively low styrene content.

In addition, the vulcanizable rubber composition for making tires in the present invention also includes Low Polycyclic Aromatic (PCA) oil as processing oil. Suitable low PCA oils include but are not limited to Treated Distillate Aromatic Extracts (TDAE) Oil, Residual Aromatic Extracts (RAE) Oil, Mild Extraction Solvate (MES) Oil, and Heavy Naphthenic Oils.

Suitable low PCA oils include oils having a glass transition temperature (Tg) in the range of about -40 to about -80 ° C. TDAE oils generally have a Tg in the range of about -44 to -50 ° C, RAE oils generally have a Tg in the range of -36 to -44 ° C, and MES oils generally have a Tg in the range of -57 to about -63 ° C. Have Heavy naphthenic oils generally have a Tg in the range of about -42 to about -48 ° C. Suitable low PCA oils include those having a polycyclic aromatic content of less than 3% by weight as measured by the IP346 method.

In one embodiment, the raw PCA oil is used in the range of about 10 to about 70 phr. In particular, TDAE oil may be included in the range of 26.5 to 28.5% based on the pure rubber polymer content.

The styrene-butadiene copolymer thus prepared has a total solid content in the polymerization solvent of 10 to 40%, preferably 15 to 25% (90% or more of polymerization conversion), and a weight average molecular weight (Mw) of 500,000 to 1.5 million. High molecular weight distribution ratio (MWD) is characterized in that it satisfies 1.8 to 3.0.

The process for obtaining such styrene-butadiene copolymer is continuous solution polymerization at 73 to 77 ° C, and the process oil added Mooney viscosity is in the range of 57 to 67 ML (1 + 4) / 100 ° C, 23 to 27 weight Styrene content of 46% and vinyl content of 46 to 54% by weight, and when applied to the silica standard compounding method characterized in that it simultaneously comprises a characteristic that the difference in Mooney viscosity before and after compounding ( Δ MV) does not exceed 40. Since the vinyl content is affected by the polymerization temperature, it is difficult to obtain a vinyl content of about 50% by weight when the polymerization is performed at a high temperature, so that the polymerization is performed at a relatively low polymerization temperature. In this case, the silica standard compounding method means that 70 phr of silica is added as a reinforcing material.

In particular, in order to obtain a high Mooney viscosity SSBR of the polymer, the input amount of the anion catalyst (mainly using NBL catalyst) should be reduced, but in this case, the reaction rate is slow and the polymerization rate is low due to the low reaction temperature and the small amount of catalyst. Since it is not easy to obtain a high Mooney viscosity SSBR of the polymer, in the present invention, a method of obtaining a high molecular weight SSBR using a coupling agent capable of binding molecular-molecules after obtaining a low molecular weight SSBR polymer by first increasing the amount of NBL catalyst Is applied.

At this time, the polymerization is adjusted in the range of 57 to 67 ML (1 + 4) / 100 ℃ of the process oil-added and the total solids in the range of 10 to 40%, preferably in the range of 15 to 25% (polymerization conversion rate 90 Preferably at least%) until a styrene-butadiene copolymer solution is formed. It is also preferred that the primary, secondary and tertiary steel reactors are CSTR reactors.

Generally, solvents used in styrene-butadiene copolymers (SBR) elastomers include aliphatic hydrocarbons such as n-hexane, n-heptane, n-octane; And aromatic hydrocarbons such as toluene, benzene and o-xylene.

The present invention discloses a solution styrene-butadiene copolymer (SBR) which satisfies all properties of excellent silica processability, wear resistance, wet road friction and rotational resistance. The novel copolymers developed by the present invention have a styrene concentration in the range of 23 to 27% by weight, a high vinyl concentration in the range of 46 to 54% by weight, and a process oil added Mooney viscosity of 57 to 67 ML (1 + 4) / 100. It is particularly useful for providing energy-saving tires as high-vinyl rubber-needle solution polymerization SBRs in the range of ° C. That is, through a continuous solution polymerization process, higher content of vinyl and increased Mooney viscosity in the copolymer, a styrene-butadiene copolymer to maximize physical property coordination in the polymer composition and consequently apply the composition as an energy saving tire. It was realized to obtain.

The present invention also provides a continuous solution polymerization; Processed oil added Mooney viscosity in the range of 57 to 67 ML (1 + 4) / 100 ° C. and vinyl content in the range of 46 to 54% by weight; And maintaining a styrene content of 23 to 27% by weight.

The continuous solution polymerization process is usually carried out at a temperature in the range of 73 to 77 ℃, preferably 74 to 76 ℃. The process oil added Mooney viscosity is preferably maintained in the range 57 to 67 ML (1 + 4) / 100 ° C, preferably 59 to 62 ML (1 + 4) / 100 ° C. The total solids are in the range of 10 to 40% by weight, preferably 15 to 25% by weight, the combined styrene content is in the range of 23 to 27% by weight, preferably 24 to 26% by weight, and the vinyl content is 46 to 54. It is in the range of 48% by weight, preferably 48 to 52% by weight.

The weight average molecular weight is in the range of 500,000 to 1.5 million g / mole, preferably 900,000 to 1.5 million g / mole, and the molecular weight ratio is in the range of 1.8 to 3.0.

According to the present invention, the continuous solution polymerization process for preparing the SBR copolymer having the differentiated features comprises the following steps:

First step: The styrene-based monomer, butadiene-based monomer and the solvent are mixed, and then adjusted to a moisture content of 5ppm or less and DBMg 0.005 to 0.25phr is added to prepare a premix.

Second step: The premix is added to the first reactor and DTHFP and NBL are added, but the input amount of DTHFP is injected within a range of 2 to 10 times the molar amount of NBL, and then held at 73 to 77 ° C. for 50 minutes.

Third step: During the transfer of the polymerization reaction in the primary reactor to the secondary reactor, divalent / 3 aniline having an epoxy group was added and held at 73 to 77 ° C for 30 minutes.

Fourth Step: After transfer of the polymerized reaction in the secondary reactor to the third reactor, 0.12phr of a solid rubber-based alcohol or phosphate polymerization terminator and 1.0phr of a phenolic or amine antioxidant are added, and the total solid content 10 Maintained within to 40% and then the solid rubber is dried to obtain a styrene-butadiene copolymer.

In summary, the method used in the following examples can be specifically performed as follows:

First, the styrene and butadiene weight ratio is 25:75 and the styrene, butadiene, n-hexane is mixed so that the total amount of n-hexane, the styrene and butadiene as the solvent is 5/1 by weight, and then the water content is less than 5ppm A premix was prepared by adjusting and adding 0.005 to 0.25 phr of DBMg as a cocatalyst.

Secondly, the premix is introduced into a primary reactor equipped with a stirrer, and DTHFP is added together with NBL as a main catalyst as a randomizing agent / vinyl regulator, but the amount of DTHFP is injected 2 to 10 times compared to the molar amount of NBL.

Third, in a primary reactor, the mixture was held at 73 to 77 ° C. for 50 minutes, and then a divalent or trivalent epoxy-based aniline having an epoxy group was added as a coupling agent in the middle of the transfer line while transferring the polymerization reaction to a secondary reactor equipped with a stirrer. 30 minutes at 73 to 77 ℃ in the secondary reactor.

Fourth, the polymerization reaction in which the coupling reaction is completed in the secondary reactor is transferred to the third reactor, which is a steel reactor, and then the living polymer which may remain in the styrene-butadiene copolymer that maintains the total solid content in the range of 10 to 40%. To stop the reaction, a small amount of 0.12phr (parts for hundred rubber) of ethanol or phosphate reaction stopper and 1phr of phenol or amine antioxidant were added and stirred to obtain a polymer.

The product formed in the reactor is a polymer solution and must be stripped to become a solid polymer. The stripping process uses a method of evaporating a solvent of hexane, which is a solvent present in the polymer solution, using steam. The solvent is removed by boiling the polymer solution in water for about 30 minutes using low pressure steam. After drying for 4 minutes in a 100 ℃ roll mill to obtain a final solid styrene-butadiene copolymer.

The novel copolymers developed in the present invention have a styrene concentration in the range of 23 to 27% by weight, a high vinyl concentration in the range of 46 to 54% by weight and a Mooney viscosity of 57 to 67 mL (1 + 4) / 100 ° C. added to the processing oil. It is particularly useful for producing energy-saving tires, which satisfies the high range of.

In addition, according to the present invention, based on 100 parts by weight (phr) of the elastomer, the prepared styrene-butadiene copolymer of about 40 to about 90 phr; About 10 to about 60 phr of at least one additional elastomer; And from about 10 to about 70 phr of a processing oil having a glass transition temperature of about -80 to about -40 ° C. and a polycyclic aromatic content of less than 3% by weight as measured by the IP346 method. An energy-saving tire can be provided.

Other elastomers that can be used with SBR can then include many general purpose elastomers, as known in the art.

Rubber or elastomers containing olefinic unsaturation are intended to include both natural rubber and its various raw and modified forms, as well as synthetic rubber. Representative synthetic polymers are those formed from homopolymerization products of butadiene and its homologues and derivatives such as methylbutadiene, dimethylbutadiene and pentadiene as well as copolymers such as butadiene or its homologues or derivatives together with other unsaturated monomers. In the latter case, acetylene such as vinyl acetylene; Olefins such as isoprene (polymerize to form IR rubber); Vinyl compound,

For example acrylic acid, acrylonitrile, which polymerizes with butadiene to form NBR, methacrylic acid and styrene, where styrene polymerizes with butadiene to form SBR, as well as vinyl esters and various unsaturated aldehydes, ketones and ethers. Such as acrolein, methyl isopropenyl ketone and vinylethyl ether. Specific examples of synthetic rubbers include neoprene (polychloroprene), polybutadiene (including cis 1,4-polybutadiene), polyisoprene (including cis-1,4-polyasoprene), butyl rubber, halobutyl rubber such as chlorobutyl Rubber or bromobutyl rubber, styrene / isoprene / butadiene rubber, copolymers of 1,3-butadiene or isoprene with monomers such as styrene, acrylonitrile and methyl methacrylonitrile, as well as ethylene / propylene terpolymers Copolymers (also known as ethylene / propylene / diene monomers (EPDM)), and in particular ethylene / propylene / dicyclopentadiene terpolymers. Additional examples of rubbers that can be used include carboxylated rubbers, silicon-bonded and tin-linked star-branched polymers. Preferred rubbers or elastomers are polybutadiene, SBR and natural rubber or polyisoprene.

In one embodiment, the rubber in combination with SBR is preferably at least one diene rubber. For example, one or more rubbers can be cis 1,4-polyisoprene rubber (natural or synthetic), 3,4-polyisoprene rubber, emulsification and solution polymerization-induced styrene / isoprene / butadiene rubber, emulsification and solution polymerization -Induced styrene / butadiene rubber, emulsification and solution polymerization-derived isoprene / butadiene rubber, emulsification and solution polymerization-derived styrene / isoprene rubber, cis 1,4-polybutadiene rubber and emulsion polymerization prepared butadiene / acrylic Ronitrile copolymers are preferred.

In another embodiment, the combination of SBR with additional elastomer and raw PCA oil is such that the glass transition temperature (Tg) of the resulting elastomeric combination is in an acceptable range for use in the tire tread. Such Tg may be obtained by using a combination of additional elastomers having a Tg in the range of about −20 to about −45 ° C.

The vulcanizable rubber composition may comprise about 10 to about 100 phr of a siliceous filler. Conventional siliceous fillers that can be used in rubber compounds include conventional pyrogene and precipitated siliceous fillers (silica), but double precipitated silica is preferred. Such conventional silicas are characterized by having a BET surface area preferably in the range of about 40 to about 600, more typically about 50 to about 300 m 2 / g, as measured using, for example, nitrogen gas. Silica is also typically characterized by having a dibutylphthalate (DBP) absorption value in the range of about 100 to about 400, more typically about 150 to about 300. Silica may be expected to have an average final particle diameter in the range of 0.01 to 0.05 microns, as measured by electron microscopy, but silica particles may be smaller or larger in size.

On the other hand, the present invention provides a solution SBR with improved workability with silica used as a reinforcing agent, and consequently improves the dispersibility of the silica, thereby acting as an advantage in the wear resistance properties, containing the same amount of TDAE oil, vinyl content and styrene content And even if the weight average molecular weight is smaller than the solution SBR using a SiCl ₄ as a coupling agent having a similar Mooney viscosity, it is excellent in dispersibility, so that the reduction of rotational resistance is not so great and has excellent balance of wear resistance and rotational resistance.

It may be desirable that the rubber composition for use of the SBR of the present invention in the tire component further contains conventional sulfur-containing organosilicon compounds in the compounding process.

Specific examples of sulfur-containing organosilicon compounds that can be used according to the invention include: 3,3'-bis (trimethoxysilylpropyl) disulfide, 3,3'-bis (triethoxysilylpropyl ) Disulfide, 3,3'-bis (triethoxysilylpropyl) tetrasulfide, 3,3'-bis (triethoxysilylpropyl) octasulfide, 3,3'-bis (trimethoxysilylpropyl) tetra Sulfide, 2,2'-bis (triethoxysilylethyl) tetrasulfide, 3,3'-bis (trimethoxysilylpropyl) trisulfide, 3,3'-bis (triethoxysilyl propyl) trisulfide, 3,3'-bis (tributoxysilylpropyl) disulfide, 3,3'-bis (trimethoxysilylpropyl) hexasulfide, 3,3'-bis (trimethoxy silylpropyl) octasulfide, 3, 3'-bis (trioctoxysilylpropyl) tetrasulfide, 3,3'-bis (trihexoxysilylpropyl) disulfa De, 3,3'-bis (tri-2'-ethylhexylsilylpropyl) trisulfide, 3,3'-bis (triisooctoxysilylpropyl) tetrasulfide, 3,3'-bis (tri-t -Butoxysilylpropyl) disulfide, 2,2'-bis (methoxy diethoxy silyl ethyl) tetrasulfide, 2,2'-bis (tripropoxysilylethyl) pentasulfide, 3,3'-bis ( Tricyclonesoxysilylpropyl) tetrasulfide, 3,3'-bis (tricyclopentoxysilylpropyl) trisulfide, 2,2'-bis (tri-2'-methylcyclohexylsilylethyl) tetrasulfide, bis (Trimethoxysilylmethyl) tetrasulfide, 3-methoxy ethoxy propoxysilyl 3'-diethoxybutoxy-silylpropyltetrasulfide, 2,2'-bis (dimethylmethoxysilylethyl) disulfide, 2,2'-bis (dimethyl-s-butoxysilylethyl) trisulfide, 3,3'-bis (methyl butylethoxysilylpropyl) tetra Sulfide, 3,3'-bis (dit-butylmethoxysilylpropyl) tetrasulfide, 2,2'-bis (phenyl methylmethoxysilylethyl) trisulfide, 3,3'-bis (diphenyl isopropoxy Silylpropyl) tetrasulfide, 3,3'-bis (diphenyl cyclohexylsilylpropyl) disulfide, 3,3'-bis (dimethyl ethylmercaptosilylpropyl) tetrasulfide, 2,2'-bis (methyl Dimethoxysilylethyl) trisulfide, 2,2'-bis (methyl ethoxypropoxysilylethyl) tetrasulfide, 3,3'-bis (diethylmethoxysilylpropyl) tetrasulfide, 3,3'-bis (Ethyl di-s-butoxysilylpropyl) disulfide, 3,3'-bis (propyl diethoxysilylpropyl) disulfide, 3,3'-bis (butyl dimethoxysilylpropyl) trisulfide, 3, 3-bis (phenyl dimethoxysilylpropyl) tetrasulfide, 3-phenyl ethoxybutoxysilyl 3'-trimethoxysilylpropyl Trasulfide, 4,4'-bis (trimethoxysilylbutyl) tetrasulfide, 6,6'-bis (triethoxysilylhexyl) tetrasulfide, 12,12'-bis (triisopropoxysilyldodecyl) Disulfide, 18,18'-bis (trimethoxysilyl octadecenyl) tetrasulfide, 18,18-bis (tripropoxysilyloctadecenyl) tetrasulfide, 4,4'-bis (trimethoxysilyl- Buten-2-yl) tetrasulfide, 4,4'-bis (trimethoxysilylcyclohexylene) tetrasulfide, 5,5'-bis (dimethoxymethylsilylpentyl) trisulfide, 3,3'-bis (Trimethoxy silyl-2-methylpropyl) tetrasulfide, 3,3'-bis (dimethoxyphenylsilyl-2-methylpropyl) disulfide.

Preferred sulfur-containing organosilicon compounds are 3,3'-bis (trimethoxy or triethoxy silylpropyl) sulfides. The amount of sulfur-containing organosilicon compound in the rubber compounding composition will vary depending on the level of other additives used, but may be between 0.5 and 20 phr.

Rubber compounding compositions may be prepared by methods generally known in the rubber compounding art, such as various sulfur-curable rubber components in a variety of conventional additive materials such as sulfur donors, curing aids such as activators and inhibitors and processing additives such as oils, Those skilled in the art will readily understand that compounding may be accomplished by mixing with resins, fillers, pigments, fatty acids, zinc oxide, waxes, antioxidants and antiozonants, including tackifiers and plasticizers.

Sulfur-curing agents are used in amounts of 0.5 to 8 phr, with 1.5 to 6 phr being preferred. Typical amounts of tackifying resins, if used, include about 0.5 to about 10 phr, typically about 1 to about 5 phr. Typical amounts of processing aids include about 1 to about 50 phr. Such processing aids include, for example, aromatic, naphthenic and / or paraffinic processing oils. Typical amounts of antioxidants are from about 1 to about 5 phr. Representative antioxidants include, for example, about 1 to 5 phr of diphenyl-p-phenylenediamine.

Fatty acids may include stearic acid if used and typical amounts thereof comprise about 0.5 to about 3 phr. Typical amounts of zinc oxide include about 2 to about 5 phr.

Accelerators are used to control the time and / or temperature required for vulcanization and to improve the properties of the vulcanizate. In one embodiment, a single accelerator system can be used, ie a first accelerator. The first promoter is used in an overall amount of about 0.5 to about 4, preferably about 0.8 to about 1.5 phr. In other embodiments, a combination of first and second promoters is used, where the second promoter is used in smaller amounts, such as from about 0.05 to about 3 phr, to activate and improve the properties of the vulcanizate. Combinations of these promoters are expected to exhibit synergistic effects on the final properties and are somewhat better than those prepared using only one promoter. In addition, the delay action promoter is not affected by the normal processing temperature but can be used to produce a satisfactory cured product at the normal vulcanization temperature. Vulcanization inhibitors can also be used. Suitable types of promoters that may be used in the present invention are amines, disulfides, guanidines, thioureas, thiazoles, thiurams, sulfenamides, dithiocarbamates and xanthates. Preferably, the first promoter is sulfenamide. If a second promoter is used, the second promoter is a guanidine, dithiocarbamate or thiuram compound.

Mixing the rubber composition includes mechanical work in a mixer or extruder for a suitable period of time that can result in a rubber temperature of 100 to 170 ° C. However, in blending operations containing sulfur-containing organosilicon compounds, the temperature should not exceed 150 ° C. The appropriate period of work varies as a function of the working conditions and the volume and properties of the components. For example, the job can be 1 to 20 minutes.

The rubber composition can be incorporated into the rubber components of various tires. For example, the rubber component may be a tread (including a tread cap and tread base), sidewalls, apex, chafer. Preferably the compound is a tread.

The pneumatic tires of the present invention may be racing tires, passenger car tires, airplane tires, agricultural machinery tires, bulldozer tires, off-the-road tires, bus tires and the like. Preferably the tire is a car or bus tire.

The tire may also be radial or bias, with dual radials being preferred.

The vulcanization of pneumatic tires of the present invention is generally carried out at conventional temperatures in the range of about 100 to 200 ° C. Preferably, the vulcanization is carried out at a temperature in the range of about 110 to 180 ° C. Any vulcanization method may be used, such as heating in a press or mold, heating method using superheated steam or hot air. Such tires will be apparent to those skilled in the art and are manufactured, molded, molded and cured by several known methods.

The present invention specifies the type and content of the cocatalyst and the coupling agent in the main catalyst NBL used to prepare the solution-polymerized SBR, but the Mooney viscosity of the final product is similar but gives the molecular chain of the polymer to increase the elastic properties in the raw polymer state This facilitates the dispersion of silica particles during silica blending, and also lowers the weight average molecular weight (Mw) without significantly lowering the Mooney viscosity of the final rubber added to the process oil. Processability in compounding in kneader mixers or in extrusion operations for the manufacture of tire treads was also advantageous. As a result, high vinyl high mooney solution polymerization SBR (HVHM-SSBR) could provide solution polymerization SBR formulation that harmonizes rotation resistance, wet road friction and abrasion resistance.

The following examples illustrate the invention but are presented for illustrative purposes. All parts are parts by weight unless otherwise specified. For reference, the following experiments were carried out using a continuous laboratory scale polymerizer consisting of one 2L glass reactor, one 1L glass reactor and a 6L stainless steel reactor.

[ Comparative example  One]

Three mixtures of CSTR continuous reactors were continuously introduced with premix (mixture of normal hexane, butadiene monomer 75%, styrene monomer 25%, total solids content 16.7%) at 20 g / min, and DTHFP (PEN Specialty Chemicals 99.0) was added to the premix line. % Of the product was diluted 5% in dried n-hexane) was added to 4.5 times (0.36 phr) to NBL (Taiwan Chemetall diluted 1.0% in dried n-hexane), followed by 0.027 phr of NBL catalyst was added.

The premix was then introduced to the bottom of the polymerizer and the polymer was discharged to the top to be transferred to the secondary reactor. When the reactant was introduced into the polymerization reactor, the reaction mixture was stirred well.

The temperature inside the primary polymerizer was maintained at 75 ± 2 ° C. and the reaction time in the primary reactor was 50 minutes, followed by SiCl ₄ (Aldrich) in the middle of the transfer line while continuously transferring the reactants at a constant rate to the secondary reactor. After diluting the 99% product to 1.0%), the coupling reaction was carried out in a secondary reactor for 30 minutes.

Determine the number average molecular weight (Mn) by measuring the molecular weight of the reactant discharged from the primary reactor, the input amount of SiCl ₄ by GPC, and then the amount of SiCl ₄ corresponding to the living polymer equivalent ratio (1/4 mole of the mole number of the living polymer molecules) Was added. In Comparative Example 1, 0.011phr was added. After completion of the coupling reaction in the secondary reactor, the reactants were transferred to a 6L steel reactor, which is a tertiary reactor, at a constant speed so as to be a steady state reaction as a whole. When a certain amount of reactants were collected in the third reactor, the reaction was terminated by adding a phosphate polymerization terminator or 0.12 phr of ethanol and 1.0 phr of a phenol or amine antioxidant.

To the obtained polymer, 27.3% of TDAE (Treated Distillate Aromatic Extract) type oil was added as a processing oil, the solvent was removed by steam stripping, and then dried on a 100 ° C. roll for 4 minutes.

[ Comparative example  2]

The polymerization was carried out in the same manner as in Comparative Example-1, except that N, N'-diglycidyl-4-glycidyloxyaniline (DGGOA: product of Aldrich Co., Ltd.) having a trivalent epoxy functional group instead of SiCl _{4 was} used as a coupling agent. Diluted to 1.0% concentration in ethylbenzene). The amount of NBL charged was adjusted so that the Mooney viscosity had a value similar to that of Comparative Example-1 after adding 27.3% of the processed oil based on the solid rubber in the polymerization reaction.

The amount of NBL added was 0.035 phr, and DTHFP was added 4.5 times compared to NBL mole as in Comparative Example-1. DGGOA also measured the number-average molecular weight of the first reactor polymer and introduced it as an equivalent ratio of the number of moles of living polymer (1/3 mole of the number of moles of living polymer), which corresponds to 0.035 phr.

[ Example -One]

The polymerization was carried out in the same manner as in Comparative Example-1, except that DBMg (Aldrich's 1.0M solution polymerization in Heptane) was premixed with 0.015 phr in the premix, and 20 g of DBMg-containing premix was passed to the first reactor through a premix transfer line. was charged at a rate of / min.

After adding 27.3% of the processed oil to the polymerization reaction, the amount of NBL injected was adjusted so that the Mooney viscosity had a value similar to that of Comparative Example-1. The amount of NBL added is 0.015 phr and the DBMg / NBL molar ratio is 0.45 / 1. DTHFP was added at a molar ratio of 4.5 times that of NBL as in Comparative Example-1.

SiCl ₄ Instead, the bis (2,3-epoxypropyl aniline) (GAN) containing a divalent epoxy functional group was measured in the number average molecular weight of the primary reactor polymer as in Comparative Example-1, and 0.7-equivalent ratio of the number of moles of living polymer (Living 0.35 mole of polymer mole number), which corresponds to 0.019 phr.

[ Example -2]

In order to compare with Comparative Example-2, polymerization was carried out in the same manner as in Example-1. However, the coupling agent is DGGOA containing a trivalent epoxy functional group instead of bis (2,3-epoxypropyl aniline) containing a divalent epoxy functional group, and the polymerization reaction of the primary reactor is analyzed by GPC to measure the number average molecular weight Mn. Thereafter, a 100% equivalence ratio of the moles of molecules of the living polymer, that is, one third of the number of moles of living polymer was continuously added.

The NBL dose was adjusted so that the Mooney viscosity of the final rubber reactant including oil was similar to that of Comparative Example 1-2 and Example 1, and the NBL dose was 0.030 phr. The DBMg / NBL molar ratio was 0.23 / 1 and DGGOA was added at 0.046 phr.

[ Example -3]

The polymerization was carried out in the same manner as in Example-2 to compare with Comparative Example-2 and Example-2. However, the coupling agent used bis (2, 3- epoxypropyl aniline) which has a bivalent epoxy functional group instead of DGGOA.

After the polymerization reaction of the primary reactor was analyzed by GPC, the number average molecular weight Mn was measured, and the equivalent ratio of the molecular moles of the living polymer, that is, 1/2 of the number of moles of the living polymer was continuously added. The NBL dose was adjusted so that the final rubber reactant Mooney Viscosity (MV) including oil was similar to Comparative Example-2 or Example-2, and the NBL dose was 0.021 phr.

The DBMg / NBL molar ratio was 0.32 / 1 and the dose of bis (2,3-epoxypropyl aniline) was 0.037 phr.

<Physical analysis>

* Combined styrene monomer and vinyl content : Varian VNMRS 500 Mhz NMR was analyzed using a solvent, 1,1,2,2-tetrachloroethane D2 from Cambridge Isotope was used.

Mooney Viscosity : Monsanto MV2000E was used to measure ML 1 + 4 using Rotor Speed 2 ± 0.02rpm and Large Rotor at 100 ° C. At this time, the sample used was left at room temperature (23 ± 3 ℃) for more than 30 minutes, collected 27 ± 3g and filled into the die cavity was measured by operating the platen.

* -S / R (Stress relaxation): After the MV measurement was completed, the sample remaining in the die cavity was measured for its slope by plotting the correlation of Mooney viscosity change versus time with the rotor stopped for 2 minutes.

* Mw : Waters GPC 2414 (Refractive Index Detector, Waters 486 Tunable Absorbance, using a% 15 HPLC pump) model was analyzed at 40 ℃ with THF solvent, the column was Styragel HR No. 3,4,5 were used in series.

Physical property measurement results are summarized in Table 1 below.

Item Comparative Example-1 Comparative Example-2 Example-1 Example-2 Example-3 NBL phr 0.027 0.035 0.015 0.030 0.021 DTHFP / NBL molar ratio 4.5
(0.36 phr) 4.5
(0.46 phr) 4.5
(0.20 phr) 4.5
(0.40 phr) 4.5
(0.28 phr) DBMg / NBL molar ratio - - 0.45
(0.015 phr) 0.23
(0.015 phr) 0.32
(0.015 phr) SiCl ₄ / living polymer molar ratio 0.25
(0.011 phr) - - - - DGGOA / Living Polymer Molar Ratios - 0.33
(0.034 phr) - 0.33
(0.046 phr) - GAN / Living Polymer Molar Ratios - - 0.35 (0.019 phr) - 0.5
(0.037phr) Sum SM% 26.3 26.5 24.8 25.5 26.4 vinyl % 49.1 49.5 46.3 49.0 48.7 Aromatic oil%
(TDAE) 27.3 27.3 27.3 27.3 27.3 Oiled MV 64 63 61 60 58 -S / R 0.418 0.424 0.360 0.342 0.356 Mn (Mn before coupling) 666,683
(394,841) 605,147
(271,784) 635,608
(379,873) 483,399
(199,729) 433,681
(279,218) Mw (Mw before coupling) 1,404,546
(877,412) 1,392,352
(589,561) 1,313,325
(843,856) 1,109,379
(443,022) 1,021,370
(668,461) MWD 2.11 2.30 2.08 2.29 2.36

As shown in Table 1, the NMR analysis of the polymer obtained in Comparative Example 1 showed that the vinyl content was 49.1%, the styrene monomer content was 26.3%, and the oily Mooney viscosity was 64, but the weight average molecular weight Mw was about 1.4 million g / mole. It was higher than 1.13 million to 1.10 million g / mole of Examples 1-3 using the bivalent or trivalent epoxy coupling agent and the promoter DBMg.

On the other hand, the -S / R value, which can measure the degree of branching of the polymer, is considerably larger than those of Examples 1 to 3, which is due to the linear molecular structure, and the rubber polymer of such a structure is intermolecular entanglement of the raw material rubber before crosslinking. Because of low elasticity (Entanglement), even if the molecular weight is large, the addition of low molecular weight oil is more likely to occur in the polymer molecular chain than the polymer with the molecular chain, the fluidity is increased and the Mooney viscosity is lowered. This type of rubber polymer deteriorates the dispersibility because the shear force transmitted from the device for dispersing filler such as silica cannot be effectively transmitted to silica during the formulation of UHP tires using a large amount of silica. The Mooney viscosity may cause a problem of poor machinability. Because of this, the important properties of the tire, in particular, wear resistance, low fuel consumption or braking performance such as wet grip can be a factor that falls.

In addition, the polymer obtained in Comparative Example 2 has a vinyl content of 49.5%, and DGGOA having the same coupling agent having a weight average molecular weight of about 1.39 million while having a Mooney viscosity of 63 after adding 27.3% of TDAE oil as a processing oil. And a value greater than 1,110,000 in Example-2 using the crude catalyst DBMg. On the other hand, the value of -S / R is 0.424, which is higher than 0.342 of Example-2, and it can be seen that a polymer having a linear molecular chain is produced when the promoter DBMG is not used.

Also, comparing Comparative Example-1 using SiCl ₄ as a coupling agent and Comparative Example-2 using DGGOA, an epoxy-based aniline, as a coupling agent, there was a large difference in terms of oil-extended MV or weight average molecular weight added with processed oil. Although it is the case of Comparative example -2 with an epoxy-based coupling agent is a polar group due to the coupling agent, such as -OH group in a molecular chain present in the affinity with the surface polarity of silica was compared with SiCl ₄ example -1 Rather, it can be easily confirmed from the difference in the Mooney viscosity between the raw rubber and the compound rubber after silica blending. That is, we identify the advantage in terms of processability △ MV is low in the rubber with silica affinity (see Table 3).

In summary, the polymer obtained in Example 1 has a vinyl content of 46.3% and a Mooney viscosity of 61 after oil addition, while the weight average molecular weight is about 1.13 million g / mole, and the same molar ratio of SiCl _{4 to the} mole ratio of DTHFP and living polymer is the same. Was added to show a value lower than the weight average molecular weight of 1.4 million of Comparative Example-1 having a similar Mooney viscosity. This is believed to be due to the formation of branches in the molecular chain by the promoter DBMg.

However, the reason why the absolute value of the -S / R value is higher than that of Example-2 using the same promoter DBMg is that the elasticity of the raw rubber is low, that is, the degree of branching is low. It is understood that branching is smaller than that of Example-2 using DGGOA having a trivalent branching degree using a linear linear compound.

In addition, the polymer obtained in Example 2 had a vinyl content of 49.0% and a process oil added Mooney viscosity of 60 mL (1 + 4) / 100 ° C., while having a very low weight average molecular weight of about 11.11 million. And -S / R value was also very low 0.342 compared to 0.424 of Comparative Example-2. It is believed that this is because the Mooney viscosity decrease due to molecular entanglement is less than that of Comparative Example-2 with little branching, even after oil addition, due to intramolecular branch formation by cocatalyst DBMg as described above.

Meanwhile, the polymer obtained in Example 3 using bivalent coupling agent bis (2,3-epoxypropyl aniline) and DBMg had a vinyl content of 48.7% and a Mooney viscosity of 27.3% of TDAE oil as a processing oil, as shown in Table 1. 58 M (1 + 4) / 100 ° C while Mw was the lowest, as much as 102 million.

In addition, Example-2 using the trivalent epoxy coupling agent and DBMg simultaneously at 0.356 compared to 0.424 of Comparative Example-2 and 0.342 of Example-2 using DGGOA and DBMg together with -S / R is also a trivalent coupling agent DGGOA. Although larger than DGGOA and less than Comparative Example-2 without DBMg, branching by DBMg has a significant effect on the elastic properties of raw rubber, and the number of branches of some coupling agents also affects branching. It became.

[ Vulcanization Of polymer  evaluation]

Table 3 below shows the properties of the vulcanized rubbers of the rubber polymers listed in Table 1. In order to understand the processability of polymer materials and important physical properties after crosslinking, the main formulas affecting the difference of Mooney viscosity before and after compounding ( △ MV) and UHP tire performance after crosslinking according to the formulation formula shown in Table 2 using silica as filler. Physical properties and the like were evaluated. As a formulation, a prescription such as Table 2 was used.

Compounding agent Compound name / product name Parts by weight (phr) Remarks Rubber LG SSBR 137.5 Primary formulation Silica Degussa 7000GR 70 X50S (Degussa) 50% carbon black and 50% bis (3-triethoxysilylpropyltetrasulfan) 5.0 Stearic acid - 1.0 ZnO - 3.0 Secondary formulation 6PPD N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine, Flexsys 1.5 sulfur - 1.75 Tertiary formulation CZ N-t-butyl-2-benzothiazyl sulfonamide, Flexsys 1.8 DPG Diphenylguanidine, Flexsys 0.8

- Compounding method and cross-linking specimens manufactured by the mixing equipment is a Thermo-fisher scientific four 300cc was used Haake Mixer, 50 ℃, was used to make specimens for physical property evaluation to thereby prepare a rubber sheet in 6-inch roll mill.

Primary formulation: Rubber, silica and stearic acid were added to a Banbury type Haake mixer and mixed until the rotor speed reached 55 rpm and the starting temperature reached 95 ° C. to 150 ° C. (approximately 6 minutes). The primary blend thus obtained is sufficiently cooled at room temperature for at least 2 hours.

Second blend: Put the sufficiently cooled primary blend back into the Haake mixer, add ZnO and the antioxidant 6PPD and mix for 4 minutes at 55 rpm.

Tertiary compounding: Sulfur, CZ, DPG and the secondary compound sufficiently cooled for 2 hours were added thereto, and the mixture was mixed at a rotor speed of 55 rpm for 3 minutes. At this time, the starting temperature was set to 60 ° C. so that scorch, which is an early crosslinking phenomenon, was not generated during the blending process. When tertiary compounding was completed, the compound was used to prepare a crosslinking specimen after sheet molding to a thickness of 4 mm using a roll mill.

Akron Wear specimens and low fuel consumption / wet Grip specimens were prepared by crosslinking using a crosslinking specimen preparation press at 170 ° C. for 20 minutes.

Abrasion resistance was measured by volume reduction by 3,000 bone wear after 500 pre-wears under 10lb load at room temperature using Yasuda, Japan No.152 Akron Type Abrasion Tester.

The tan δ property, which is the most important characteristic for low fuel economy tires, is heated at 2 ℃ / min in the range of -40 ~ + 70 ℃ at 10Hz, Prestrain 5%, Dynamic Strain 0.5% using Gabo Explexor 500N. The experiment was conducted.

Item unit Comparative Example-1 Comparative Example-2 Example-1 Example-2 Example-3 Raw MV MV 64 63 61 60 58 Compound MV MV 110 105 100 95 95 △ MV MV 46 42 39 35 37 Abrasion Resistance AKRON Los cc 0.135 0.127 0.121 0.114 0.119 tanδ 0 ° C (W.grip) - 0.773 0.780 0.821 0.846 0.851 60 ° C (W.grip) - 0.149 0.146 0.157 0.155 0.160

As shown in Table 3, the difference between △ MV before and after silica blending of Comparative Example-1 using SiCl ₄ , a tetravalent coupling agent commonly used in SSBR manufacture, is 46, whereas a divalent or trivalent epoxy coupling agent is used. used in Comparative example 2 and example 1 was has the △ MV favorable than this lower workability characteristics of 1-3, in particular 2 or 3, an epoxy-based coupling agent, and at the same time △ MV of examples 1-3 using a cocatalyst of DBMg is It can be seen that the 39 to 35 is significantly lower than 46 in terms of workability.

DBMg forms 1: 1 or 1: 2 complexes (RR ' ₂ MgLi, RR' ₃ MgLi ₂ ) with NBL catalysts and is known to have a different catalytic function than when NBL alone is used. Molecules are produced to produce highly elastic rubbers with small -S / R values (absolute values), which makes them appear to have good dispersion during silica blending.

In the physical properties after crosslinking of the compound, especially in the wear resistance (the smaller the glass is) and the wet grip property (wet road friction, 60 ℃ tan δ, the higher the glass), NBL alone and SiCl ₄ than trivalent epoxy-based epoxy-based It can be confirmed that Comparative Examples-2 using a coupling agent and Examples 1 to 3 using NBL, DBMg, and a divalent or trivalent epoxy coupling agent are all excellent.

Particularly, as in Examples 1 to 3, the reason why △ MV is lower than Comparative Example-1 or Comparative Example-2 without DBMg before and after silica blending shows excellent characteristics in processability, as described above. This is because the use of DBMg ensures proper branching within the molecule, and this type of rubber polymer can effectively use the shear force transmitted from the device when combined with an inorganic reinforcement to disperse the reinforcement. For this reason, there is little difference of ( DELTA) MV before and after mix | blending, and it has favorable characteristics, such as abrasion resistance after crosslinking.

In addition, even when a rubber containing oil is produced by adding a low molecular weight oil to the raw rubber, the molecular intermolecular slippage is not large due to the entanglement of the molecules, thus maintaining a similar Mooney value while maintaining a similar molecular weight (ie, similar MV). Even rubber having a low molecular weight is advantageous in terms of processability, and excellent in inorganic filler dispersibility and advantageous in physical properties such as abrasion resistance after crosslinking). The high vinyl high Mooney viscosity SSBR having such characteristics has a good effect of improving the wet grip and abrasion resistance of tires containing a large amount of silica, and has a similar Mooney viscosity, but a high molecular weight rubber polymer (for example, Comparative Example 1 ) LRR property (0 ℃ tanδ, the smaller the value of glass) is not so much deteriorated, showing the suitable characteristics for UHP tire use.

In addition, Comparative Examples-2 and Examples 1 to 3 using an epoxy-based coupling agent exist on the surface of silica because they have a -OH group in the molecular chain which has better affinity with silica than Comparative Example-1 using SiCl ₄ as a coupling agent. It is considered to be affinity with silanol groups or siloxanes, and especially hydrogen bonding with silanol groups to help dispersibility of silica, and epoxy groups may be added to the molecule when comparing Examples 1 to 3 with the same amount of DBMg added during the polymerization reaction. In the case of Example-2 using a trivalent DGGOA containing a lot of workability ( △ MV) and wear resistance than Example-1 or Example-3 using bis (2,3-epoxypropyl aniline) which is a divalent epoxy coupling agent , LRR (60 ℃ tanδ, the smaller the better fuel economy) was found to be excellent.

Example 2 using DGGOA and DBMg had the best balance in three main physical properties required for UHP tires such as abrasion resistance, low fuel efficiency (60 ° C. tanδ) and Wet Grip resistance (0 ° C. tanδ) after crosslinking.

In conclusion, the HVHM-SSBR for the UHP tire developed in the present invention satisfies 62 ± 5, 50 ± 4% of vinyl content (based on polymer) and 25 ± 2% of styrene monomer with 37.5 phr of processing oil. In comparison to SSBR using NBL / SiCl ₄ , a high molecular weight solution SBR, the weight average molecular weight Mw is relatively low and Mw satisfies 100 ± 500,000 range without sacrificing the Mooney viscosity. Is characterized by SSBR having a range of 1.8 to 3.0, preferably 1.5 to 2.5, and having excellent affinity with silica by introducing a polar functional group at the end of the molecular chain. Because of this, as the reinforcing material as shown in Table 2, the increase in Mooney viscosity after mixing with silica is lower than that of SSBR using NBL / SiCl ₄ , and it has excellent wear resistance and good wet grip without significant deterioration of LRR. SBRs with well matched properties could be produced. In other words, they could identify what is involved in the control of branching defined by these three main variables (high combined vinyl content, high Mooney viscosity, polymerization temperature).

Claims (15)

It contains the reaction product of the continuous solution polymerization from styrene monomer and butadiene monomer, process oil added Mooney viscosity of 57 to 67 ML (1 + 4) / 100 ℃, styrene content of 23 to 27% by weight Styrene-butadiene copolymer, characterized in that the vinyl content of 46 to 54% by weight. The method of claim 1,
The continuous solution polymerization is performed using alkyl lithium (NBL) as the main catalyst in the range of 0.01 to 0.05 phr and dibutylmagnesium (DBMg) as the cocatalyst in the range of 0.005 to 0.25 phr (parts per hundred monomer). Styrene-butadiene copolymer. The method of claim 1,
The continuous solution polymerization is a bivalent or trivalent epoxy-based aniline having an epoxy group, and bis (2,3-epoxypropyl) aniline (GAN) 0.01 to 0.20 phr (parts per hundred monomer), or N, N'-diglyci Styrene-butadiene copolymer, characterized in that it is carried out using dimethyl-4-glycidyloxyaniline (DGGOA) 0.01 to 0.30 phr. The method of claim 3, wherein
The bis (2,3-epoxypropyl) aniline (GAN) is a styrene-butadiene copolymer, characterized in that 0.01 to 0.04phr. The method of claim 3, wherein
The N, N'-diglycidyl-4-glycidyloxyaniline (DGGOA) is a styrene-butadiene copolymer, characterized in that 0.02 to 0.06 phr. The method of claim 1,
The continuous solution polymerization is a styrene-butadiene copolymer, characterized in that the ditetrahydrofuranylpropane (DTHFP) is used as a randomizing agent / vinyl content controlling agent within a range of 4.5 times the number of moles of the main catalyst NBL. The method of claim 1,
The styrene-butadiene copolymer has a total solid content of 10 to 40%, a weight average molecular weight (Mw) of 500,000 to 1.5 million g / mole, and a molecular weight distribution ratio (MWD) of 1.8 to 3.0, characterized in that Styrene-butadiene copolymers. The method of claim 1,
As the processing oil, TDAE (Treated Distillate Aromatic Extract) oil having a glass transition temperature of about -44 to about -50 ° C, Residual Aromatic Extrant (RAE) oil having a glass transition temperature of -36 to -42 ° C, -57 to One of either MES (Mild Extraction Solvate) having a glass transition temperature of about −63 ° C. or heavy naphthenic oil having a glass transition temperature of about −42 to about −48 ° C. ranges from 26.5 to 28.5 weight percent based on polymerized solid rubber Styrene-butadiene copolymers, characterized in that contained within. The process for obtaining the styrene-butadiene copolymer according to any one of claims 1 to 8 is characterized by continuous solution polymerization at 73 to 77 ° C, and a process oil added Mooney viscosity of 57 to 67 mL (1 + 4) / styrene, characterized in that 100 ℃, 23 to a styrene content of 27% by weight and 46 to a vinyl content of 54% by weight, and when the silica compounding method applied compounding before and after the Mooney viscosity difference (△ MV) is not more than 40 - butadiene Process for the preparation of coalescing. The method of claim 9,
A first step of preparing a premix by mixing the styrene-based monomer, butadiene-based monomer and a solvent, adjusting the water content to 5 ppm or less and adding DBMg 0.005 to 0.25 phr;
A second step of introducing the premix into a first reactor and injecting DTHFP and NBL, wherein the input amount of DTHFP is injected within a range of 2 to 10 times the molar amount of NBL and then stayed at 73 to 77 ° C. for 50 minutes;
A third step of adding a divalent / 3 aniline having an epoxy group to the polymerization reactor in the first reactor for 30 minutes at 73 to 77 ° C. during the transfer to the secondary reactor; And
After the completion of the coupling reaction in the secondary reactor to the tertiary reactor, 0.12phr of a solid rubber-based alcohol or phosphate-based polymerization terminator and 1.0phr of a phenol- or amine-based antioxidant are added, and the total solid content is within 10 to 40%. Maintaining and then drying the solid rubber to obtain a styrene-butadiene copolymer; Method for producing a styrene-butadiene copolymer comprising a. The method of claim 9,
The polymerization is carried out until a styrene-butadiene copolymer solution is formed in which the process oil added Mooney viscosity is adjusted within the range of 57 to 67 ML (1 + 4) / 100 ° C. and the total solids are maintained in the range of 10 to 40%. Method for producing a styrene-butadiene copolymer, characterized in that. The method of claim 9,
The primary, secondary and steel reactor is a method for producing a styrene-butadiene copolymer, characterized in that the CSTR reactor. From about 40 to about 90 phr of the styrene-butadiene copolymer according to any one of claims 1 to 8, based on 100 parts by weight of an elastomer (phr); About 10 to about 60 phr of at least one additional elastomer; And about 10 to about 70 phr of a processing oil having a glass transition temperature of about -80 to about -40 ° C and a polycyclic aromatic content of less than 3% by weight as measured by the IP346 method. Energy-saving tire, characterized in that. The method of claim 13,
The process oil is a TDAE oil having a glass transition temperature of about -44 to about -50 ° C, a RAE oil having a glass transition temperature of -36 to -42 ° C, and an MES having a glass transition temperature of -57 to about -63 ° C. Or heavy naphthenic oil having a glass transition temperature in the range of about -42 to about -48 ° C. The method of claim 13,
Furthermore, the energy-saving tire, characterized in that to use silica in the range of 20 to 130 parts by weight based on 100 parts by weight of rubber as a reinforcing agent.