KR102443664B1 - Tire tread composition with improved wet braking performance and tires manufactured using the same - Google Patents

Abstract

The present invention relates to a rubber composition for a tire tread having improved wet road braking performance while maintaining abrasion resistance and low fuel efficiency, and a tire manufactured using the same.
The rubber composition for a tire tread according to the present invention includes a raw material rubber containing solution-polymerized styrene-butadiene rubber modified at the terminals or both ends with amino silane and/or amine, silica, resin, and PVA, which is a water-soluble polymer, the composition tires are manufactured with
According to the present invention, by combining solution polymerization styrene butadiene rubber (SSBR) of various glass transition temperatures (Tg) with high functionalization rate and applying PVA (Polyvinylachohol), which is a resin and water soluble polymer, while maintaining the wear resistance and low fuel economy performance of the tire It can improve wet road braking performance.

Description

Tire tread composition with improved wet braking performance and tires manufactured using the same

The present invention relates to a rubber composition for a tire tread, and more particularly, to a rubber composition for a tire tread with improved wet road braking performance and a tire manufactured using the same.

In recent years, environmental problems have continuously emerged, and the transition to electric vehicles is rapidly taking place. With the transition to electric vehicles, there is a great demand for low fuel economy performance with high cruising range and fuel efficiency above all else.

In addition, as the tire labeling system is strengthened, the importance of braking performance and low fuel efficiency is increasing day by day.

Tire technology that combines the braking performance and low fuel efficiency of these tires is being developed, especially in the field of materials. In particular, it can significantly contribute to weight reduction and improved fuel economy performance of automobiles by lowering the tread depth by securing the abrasion resistance of the tread compound. Technology development is actively underway.

However, if the tread depth of the tire is lowered, it is unfavorable to the braking performance on a wet road surface, and since the tread depth, which has already been lowered due to wear during actual driving, is further lowered, there is a problem that the braking performance on a wet road surface is rapidly deteriorated.

As mentioned above, in order to manufacture a tread rubber composition to increase the wet road braking performance while maintaining the wear resistance and low fuel efficiency of the tire, silica is mainly used as a filler, and raw rubber such as SBR, NR, BR is combined, It is most important to configure the composition and ratio of additives that are advantageous for braking performance compared to other additives such as oil.

It is an object of the present invention to prepare a rubber composition having improved wet road braking performance while maintaining the above-described wear resistance and low fuel economy performance.

Another object of the present invention is to realize a rubber composition that minimizes the trade-off of abrasion resistance and low fuel efficiency and has improved wet road braking performance.

Another object of the present invention is to provide a tire including a tire tread manufactured by using the rubber composition for a tire tread.

In order to achieve the above object, a rubber composition for a tire tread according to an embodiment of the present invention may be prepared by adding 100 parts by weight of raw rubber; 80 to 120 parts by weight of silica; 5 to 30 parts by weight of resin; 5 to 30 parts by weight of PVA, which is a water-soluble polymer, and the raw rubber is 20 to 50 parts by weight of a solution-polymerized styrene-butadiene rubber that is free from oil and has both ends modified with amine and amino silane; It contains 20 to 50 parts by weight of solution-polymerized styrene-butadiene rubber terminal-modified with amino silane containing 37.5 parts by weight of oil.

The solution-polymerized styrene-butadiene rubber having both ends modified with the amine-based and amino silane-based compounds has a glass transition temperature (Tg) of about -60°C, styrene is 13 to 17% by weight, and vinyl content can be 23 to 27% by weight. .

The solution-polymerized styrene-butadiene rubber terminally modified with amino silane containing 37.5 parts by weight of the oil added has a glass transition temperature (Tg) of about -53°C, styrene is 23 to 27% by weight, and vinyl content is 18 to 22% by weight. can

The silica may be a highly dispersible silica having a CTAB adsorption of 140 to 280 m ² /g and a hydrogen ion index of 5 to 8 pH.

The resin may have a softening point of 90 to 130 ℃ and a glass transition temperature (Tg) of 20 to 90 ℃, mainly aliphatic or naphthenic and aromatic copolymers.

The water-soluble polymer PVA may have a Tg of 40 to 80° C. and a molecular weight of 10,000 to 50,000.

The raw rubber may further include 0 to 40 parts by weight of butadiene rubber and 0 to 20 parts by weight of natural rubber.

The tire tread rubber composition according to the present invention combines solution polymerization styrene butadiene rubber (SSBR) of various glass transition temperatures (Tg) with a high functionalization rate, and increases the amount of silica as a filler, but adds an optimal content and helps disperse silica For this purpose, by applying PVA (Polyvinylachohol) which is oil, resin, and water solvent as a plasticizer, it is possible to improve the wet road braking performance while maintaining the abrasion resistance and low fuel efficiency of the tire.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily carry out the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

The present invention relates to a rubber composition for a tire tread including a raw material rubber containing solution-polymerized styrene-butadiene rubber, silica, a resin, and a water-soluble polymer, PVA, in which the terminal or both ends are modified with amino silane and/or amine.

Specifically, the rubber composition of the tire tread according to the present invention contains 80 to 120 parts by weight of silica, 5 to 30 parts by weight of resin, and 5 to 30 parts by weight of PVA, which is a water-soluble polymer, based on 100 parts by weight of the raw rubber, and the raw rubber is adhesive. 20 to 50 parts by weight of solution-polymerized styrene-butadiene rubber modified with amine and amino silane at both ends without oil, 20 to 50 parts by weight of solution-polymerized styrene-butadiene rubber modified with amino silane and containing oil. .

The silica, which is a filler, can dramatically improve low fuel consumption performance, but does not significantly improve braking performance compared to the prior art. In addition, since silica has hydrophilicity, interaction with raw rubber is weak. As a result, the mixing of raw rubber and silica is not uniform, and there is a risk of lowering the wear resistance of the tire.

In order to solve the above disadvantages, the rubber composition for a tire tread according to an embodiment of the present invention includes solution polymerization styrene butadiene rubber.

In general, solution polymerization styrene-butadiene rubber is produced by continuous and batch methods. The solution polymerization styrene-butadiene rubber manufactured by the continuous method is disadvantageous in terms of rolling resistance compared to the rubber manufactured by the batch method due to a large amount of low-molecular substances, but has excellent processability. excellent braking performance. Accordingly, by using the solution-polymerized styrene-butadiene rubber prepared by a continuous method, the processability of the solution-polymerized styrene-butadiene rubber having a high molecular weight can be supplemented and the braking properties of silica can be supplemented.

The solution-polymerized styrene-butadiene rubber may be modified with an amine or amino silane group at the terminal and/or both ends. When the styrene-butadiene rubber whose terminal is modified with an amine or amino silane group is used, the interaction between the rubber and the silica and/or carbon black is improved, so that the dispersibility of the silica and/or carbon black in the raw rubber can be improved. As a result, it is possible to manufacture a tire with increased braking performance, adjustment stability, and abrasion resistance with the rubber composition for a tire tread including the rubber.

The amino silane group may be an aminoalkoxysilane such as aminopropyltrimethoxysilane or aminopropyltriethoxysilane, and the amine group may be an amine group disclosed in US-B-6,936,669 or KR-A-2017-0038983, but in particular The present invention is not limited thereto.

The solution-polymerized styrene-butadiene rubber may be a mixture of an oil-free solution-polymerized styrene-butadiene rubber and an oil-containing solution-polymerized styrene-butadiene rubber.

The oil-free solution polymerization styrene-butadiene rubber has a glass transition temperature (Tg) of -70 to -50 ° C., styrene is 13 to 17 wt%, and vinyl content is 23 to 27 wt%. It is preferable that both ends are modified.

The oil-free styrene butadiene rubber may be included in an amount of 20 to 50 parts by weight based on 100 parts by weight of the raw rubber, preferably 30 to 45 parts by weight, and more preferably 35 to 40 parts by weight.

When the raw material rubber contains both terminal-modified solution polymerization styrene-butadiene rubber that does not contain oil having a styrene content, a vinyl content, and a glass transition temperature (Tg) in the above ranges, the terminal-modified group and the silica surface hydroxyl group It has the effect of improving abrasion performance and low fuel economy performance by maximizing the reaction of silica and rubber and improving the dispersibility and bonding strength between silica and rubber.

Solution-polymerized styrene-butadiene rubber containing oil has a glass transition temperature (Tg) of about -60 to -40°C, styrene is 23 to 27% by weight, and vinyl content is 18 to 22% by weight. it is preferable The oil may be a natural oil or a TDAE oil, the natural oil may be soybean oil, the TDAE oil has a total PAHs content of 3% by weight or less, a kinematic viscosity of 95 or more (210°F SUS), and aromatics in the softener 15 to 25% by weight of the component, 27 to 37% by weight of the naphthenic component, and 38 to 58% by weight of the paraffinic component. When the solution-polymerized styrene butadiene rubber includes the oil in the range of parts by weight, it is possible to improve the processability of the rubber while maintaining the hardness of the rubber composition at an appropriate level.

The oil-containing solution polymerization styrene butadiene rubber may be included in an amount of 20 to 50 parts by weight, preferably 30 to 45 parts by weight, and more preferably 35 to 40 parts by weight based on 100 parts by weight of the raw rubber. .

When solution-polymerized styrene-butadiene rubber containing oil having a styrene content, a vinyl content, and a glass transition temperature (Tg) within the above ranges is included in the raw material rubber, not only the braking performance of the tire but also the fine structure of the styrene butadiene rubber is adjusted. The wear performance can be improved at the same time.

Furthermore, by using an oil-free solution-polymerized styrene-butadiene rubber and an oil-containing solution-polymerized styrene-butadiene rubber in an appropriate mixing ratio, it is possible to provide an effect of balancing braking performance, low fuel consumption and wear performance.

The rubber composition of a tire tread according to an embodiment of the present invention may include butadiene rubber in raw rubber. In particular, as the butadiene rubber, a high-cis butadiene rubber may be more preferably used. The high-cis butadiene rubber may have a cis-1,4 content of 95 wt% or more, and a glass transition temperature (Tg) of -104 to -107 °C. The high-cis butadiene rubber has an advantageous effect of low-temperature characteristics and rebound elasticity within the cis-1,4 content and the glass transition temperature range.

The butadiene rubber may include 0 to 40 parts by weight based on 100 parts by weight of the raw rubber, and more preferably 0 to 20 parts by weight. When the content of the butadiene rubber exceeds 60 parts by weight, extrusion processability in the tread rubber composition may be deteriorated.

The raw rubber may further include a natural rubber, and the natural rubber may be a general natural rubber or a modified natural rubber. The natural rubber may include 0 to 20 parts by weight in 100 parts by weight of the raw rubber.

The rubber composition for a tire tread according to an embodiment of the present invention includes highly dispersible silica as a filler in order to improve low fuel consumption performance.

The highly dispersible silica preferably has a nitrogen adsorption of 150 to 300 m 2 /g and a CTAB adsorption of 140 to 280 m 2 /g. When the nitrogen adsorption 150 m2/g and the CTAB adsorption are 140 m2/g or less, the stiffness of the compounding rubber decreases and the handling and wet braking performance decrease. It is very difficult and the overall performance tends to decrease due to excessive rigidity improvement.

The highly dispersible silica has a hydrogen ion index of 5 to 8 pH, which is similar to the pH of general silica itself, and is typically 7 pH.

The rubber composition for a tire tread according to an embodiment of the present invention may contain a silane compound to improve dispersion of silica. Among them, TESPT (Bis-(triethoxysilylpropyl)tetrasulfide) is preferable. The TESPT (Bis-(triethoxysilylpropyl)tetrasulfide) has the effect of improving the dispersibility of silica, expressing reinforcing properties, and inducing a coupling reaction with a polymer. The TESPT (Bis-(triethoxysilylpropyl)tetrasulfide) preferably contains 6 to 10 parts by weight based on 100 parts by weight of silica. When the TESPT content is less than 6, there is a problem in that dispersibility and reinforcing properties of silica are reduced, and 10 When it exceeds, it can induce excessive coupling reaction, resulting in very low elongation of rubber, and reducing silica dispersion due to side reactions such as a bridge phenomenon that binds silica and silica in the reaction between TESPT.

The rubber composition for a tire tread according to an embodiment of the present invention may include a resin. Since the resin is mixed at a softening point or higher when the rubber composition is mixed, processability is improved, and at room temperature and the temperature of general tire driving, the resin acts as a hard part to help improve the rigidity of the rubber. The glass transition temperature (Tg) of the resin is preferably 20 to 90 °C, and the softening point is preferably 90 to 130 °C. When the stiffness decreases and exceeds 130° C., there is a problem in that the dispersibility into the raw rubber is deteriorated during mixing.

The resin may have a softening point of 90 to 130 ℃ and a glass transition temperature (Tg) of 20 to 90 ℃, mainly aliphatic or naphthenic and aromatic copolymers.

For example, the aliphatic-based resin may be, for example, a C5-based petroleum resin such as isoprene, and the naphthenic-based resin is, for example, a terpene-based resin or a DCPE (Dicyclopentadiene)-based resin. ), and the like, and the aromatic system may have 8 to 10 carbon atoms, for example, vinyltoluene, dicyclopentadiene, indene, methylstyrene, styrene, methyl indene. (Methyl indenes).

The resin has an aromatic hydrocarbon and an aliphatic or naphthenic hydrocarbon weight ratio of 30 to 60: 40 to 70. When the wet performance of the tread rubber composition is increased, the effect can be increased even with a small content. If the weight ratio of the aromatic hydrocarbon is less than 30, the glass transition temperature may be too high and the rotation resistance performance may be deteriorated, and if it exceeds 60, the wet reinforcing effect may be insignificant.

The resin preferably contains 5 to 30 parts by weight based on 100 parts by weight of the raw rubber. If it is less than 5 parts by weight, the processability and rigidity of the rubber are insignificant, and if it exceeds 30 parts by weight, there is a problem in that the wear resistance is weakened. .

The rubber composition for a tire tread according to an embodiment of the present invention may include polyvinylalcohol (PVA), which is a water-soluble polymer. The PVA preferably has a glass transition temperature (Tg) of 40 to 80 ° C. If it is less than 40 ° C, a problem of reducing the braking performance improvement effect may occur, and if it exceeds 80 ° C, the processability and silica dispersion of the rubber composition will be weakened. can

The PVA preferably contains 5 to 30 parts by weight based on 100 parts by weight of the raw rubber. If the PVA is less than 5 parts by weight, there is a problem that the effect of PVA is insignificant, and if it exceeds 30, there may be a problem that wear resistance and low fuel economy performance are rapidly deteriorated.

The tire tread rubber composition according to the present invention may further include carbon black, a softener, a vulcanizing agent, a vulcanization accelerator, and a vulcanization accelerator auxiliary.

Carbon blacks include furnace blacks such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF and ECF (furnace carbon black); acetylene black (acetylene carbon black); thermal blacks such as FT and MT (thermal carbon black); channel blacks such as EPC, MPC and CC (channel carbon black); It may be graphite, but it may be preferably HAF (High Abrasion Furnace) carbon black.

Carbon black has an iodine adsorption amount of 103-1000 mg/g, a nitrogen adsorption specific surface area (N2SA) of 118-1000 m2/g, a DBP (Dibutyl-phthalate) oil absorption of 105-495 ml/100g, and BET (Brunauer Emmett Teller) ) may have a specific surface area of 100 to 1000 m2/g. Such carbon black may contain 1 to 10 parts by weight based on 100 parts by weight of the raw rubber.

The softener is added to the rubber composition to facilitate processing by imparting plasticity to the rubber or to reduce the hardness of the vulcanized rubber, and refers to processing oils used in rubber compounding or rubber manufacturing. The softening agent (oil) is included in an amount of 1 to 6 parts by weight based on 100 parts by weight of the raw rubber.

As the softening agent, any one selected from the group consisting of petroleum oils, vegetable oils, and combinations thereof may be used, but the present invention is not limited thereto.

As the petroleum oil, any one selected from the group consisting of paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof may be used.

Representative examples of paraffinic oils include P-1, P-2, P-3, P-4, P-5, and P-6 of Michang Oil Co., Ltd., and representative examples of naphthenic oils include Michang Oil Co., Ltd. N-1, N-2, N-3, and the like, and representative examples of aromatic oils include A-2 and A-3 of Michang Oil Co., Ltd.

However, with the recent increase in environmental awareness, when the content of polycyclic aromatic hydrocarbons (hereinafter referred to as PAHs) contained in aromatic oils is 3% by weight or more, it is known that the possibility of cancer is high, TDAE (treated A distillate aromatic extract oil, a mild extraction solvate (MES) oil, a residual aromatic extract (RAE) oil, or a heavy naphthenic oil may be preferably used.

In particular, the oil used as a softener has a total content of PAHs of 3% by weight or less with respect to the entire oil, a kinematic viscosity of 95°C or higher (210°F SUS), an aromatic component in the softener of 15 to 25% by weight, and a naphthenic component TDAE oil containing 27 to 37% by weight and 38 to 58% by weight of paraffinic components may be preferably used.

TDAE oil has advantageous properties against environmental factors, such as the cancer-causing potential of PAHs, while improving the low-temperature characteristics and fuel efficiency of tire treads including TDAE oil.

Vegetable oils include castor oil, cottonseed oil, linseed oil, canola oil, soybean oil, palm oil, palm oil, peanut oil, pine oil, pine tar, tall oil, corn oil, rice bran oil, safflower oil, sesame oil, olive oil, sunflower oil, palm kernel oil, camellia oil, Any one selected from the group consisting of jojoba oil, macadamia nut oil, safflower oil, tung oil, and combinations thereof may be used.

As the vulcanizing agent, a sulfur-based vulcanizing agent, an organic peroxide, a resin vulcanizing agent, or a metal oxide such as magnesium oxide may be used. More specifically, the sulfur-based vulcanizing agent is an inorganic vulcanizing agent such as powdered sulfur (S), insoluble sulfur (S), precipitated sulfur (S), colloidal sulfur, tetramethylthiuram disulfide (TMTD), An organic curing agent such as tetraethyltriuram disulfide (TETD) or dithiodimorpholine may be used.

As the sulfur-based vulcanizing agent, specifically elemental sulfur or a vulcanizing agent producing sulfur, for example, amine disulfide, polymeric sulfur, and the like may be used.

Organic peroxides include benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, 2,5-dimethyl-2,5-di (t -Butylperoxy)hexane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 1,3-bis (t-butylperoxypropyl)benzene, di-t-butylperoxy-diisopropylbenzene, t-butylperoxybenzene, 2,4-dichlorobenzoyl peroxide, 1,1-dibutylperoxy-3, 3,5-trimethylsiloxane, or n-butyl-4,4-di-t-butylperoxyvalerate, and the like, may be used alone or as a mixture of two or more thereof.

Among them, the sulfur-based vulcanizing agent may be more preferable in consideration of the effect of improving the tensile properties of the rubber composition.

It is preferable that the vulcanizing agent be included in an amount of 1 to 3 parts by weight based on 100 parts by weight of the raw rubber in terms of making the raw rubber less sensitive to heat and chemically stable as an appropriate vulcanizing effect.

The vulcanization accelerator accelerates the vulcanization rate or promotes a delayed action in the initial vulcanization stage. Specifically, vulcanization accelerators include sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamic acid, aldehyde-amine, aldehyde-ammonia, imidazoline, xanthate, and these Any one selected from the group consisting of a mixture of can be used.

Examples of the sulfenamide-based vulcanization accelerator include N-cyclohexyl-2-benzothiazylsulfenamide (CBS), N-t-butyl-2-benzothiazylsulfenamide (TBBS), N,N-dicyclohexyl-2- benzothiazyl sulfenamide, N-oxydiethylene-2-benzothiazyl sulfenamide, N,N-diisopropyl-2-benzothiazole sulfenamide, and the like. Mixtures may be used.

Examples of the thiazole-based vulcanization accelerator include 2-mercaptobenzothiazole (MBT), dibenzothiazyldisulfide (MBTS), sodium salt of 2-mercaptobenzothiazole, zinc salt of 2-mercaptobenzothiazole, Copper salt of 2-mercaptobenzothiazole, cyclohexylamine salt of 2-mercaptobenzothiazole, 2-(2,4-dinitrophenyl)mercaptobenzothiazole, 2-(2,6-diethyl 4-morpholinothio) benzothiazole, etc. are mentioned, One type alone or a mixture of two or more types of these can be used.

As the thiuram-based vulcanization accelerator, for example, tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram disulfide, dipentamethylenethiuram monosulfide, dipentamethylenethi uram tetrasulfide, dipentamethylene thiuram hexasulfide, tetrabutyl thiuram disulfide, pentamethylene thiuram tetra sulfide, and the like, and any one of them or a mixture of two or more thereof may be used.

Examples of the thiourea-based vulcanization accelerator include thiacarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea, diorthotolylthiourea, and the like. Can be used.

Examples of the guanidine-based vulcanization accelerator include diphenylguanidine, diorthotolylguanidine, triphenylguanidine, orthotolylbiguanide, diphenylguanidinephthalate, and the like. have.

Examples of the dithiocarbamic acid vulcanization accelerator include zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, di Zinc butyldithiocarbamate, zinc diamyldithiocarbamate, zinc dipropyldithiocarbamate, complex salt of pentamethylenedithiocarbamate zinc and piperidine, hexadecylisopropyldithiocarbamate zinc, octadecyliso Zinc propyldithiocarbamate, zinc dibenzyldithiocarbamate, sodium diethyldithiocarbamate, piperidine pentamethylenedithiocarbamate, selenium dimethyldithiocarbamate, tellunium diethyldithiocarbamate, diamyl Cadmium dithiocarbamate, etc. are mentioned, Among these, 1 type alone or a mixture of 2 or more types can be used.

The aldehyde-amine-based or aldehyde-ammonia-based vulcanization accelerator includes, for example, an acetaldehyde-aniline reactant, a butylaldehyde-aniline condensate, hexamethylenetetramine, an acetaldehyde-ammonia reactant, and the like. A mixture of two or more may be used.

As the imidazoline-based vulcanization accelerator, for example, an imidazoline-based compound such as 2-mercaptoimidazoline can be used. As the xanthate-based vulcanization accelerator, for example, a xanthate-based compound such as dibutylxanthogen zinc Can be used.

Among them, N-tertiarybutyl-2-benzothiazylsulfenamide (NS), N-cyclohexyl-2-benzothiazolesulfenamide (N-cyclohexyl-2- benzothiazylsulfenamide (CZ), N,N-diphenyl guanidine (DPG), N-oxydiethylene-2-benzothiazyl sulfen amide (N-oxydiethylene-2-benzothiazyl sulfen amide), tetramethyl thiuram disulfide ( Tetrametylthiuram disulfide, TT) and mixtures thereof may be preferred.

The vulcanization accelerator is included in an amount of 1 to 1.5 parts by weight based on 100 parts by weight of the raw rubber to maximize productivity and rubber properties, particularly tensile properties, through acceleration of the vulcanization rate.

Stearic acid and zinc oxide (ZnO) are vulcanization accelerators used in combination with a vulcanization accelerator to perfect the accelerating effect. Stearic acid contains 1-4 parts by weight based on 100 parts by weight of raw rubber, zinc oxide (ZnO) Silver is contained in 4 to 6 parts by weight based on 100 parts by weight of the raw rubber.

As described above, when zinc oxide and stearic acid are used together as a vulcanization accelerator, zinc oxide dissolves in stearic acid to form an effective complex with the vulcanization accelerator, thereby facilitating the crosslinking reaction of rubber by creating advantageous sulfur during the vulcanization reaction. make it

Various additives such as an adhesive, a vulcanization retarder, an anti-aging agent, and an antioxidant may be optionally added to the rubber composition of the tire tread in addition to the above components. Any additives may be used as long as they are conventionally used in the field to which the present invention pertains, and the content thereof is not particularly limited as it depends on the compounding ratio used in a conventional rubber composition for a tire tread.

As a specific example, the pressure-sensitive adhesive further improves tack performance between rubber and rubber, and improves the mixability, dispersibility and processability of other additives such as fillers, thereby contributing to improvement of rubber properties.

As the pressure-sensitive adhesive, a natural resin-based pressure-sensitive adhesive such as a rosin-based resin or a terpene-based resin and a synthetic resin-based pressure-sensitive adhesive such as a petroleum resin, coal tar or an alkyl phenol-based resin may be used.

The vulcanization retardant serves to prevent the residual rate of insoluble sulfur from being lowered. Preferably, N-cyclohexylthiophthalimide (hereinafter abbreviated as "PVI") or salicylic acid is used. used

Specifically, the antioxidant may be appropriately selected from any one selected from the group consisting of amine-based, phenol-based, quinoline-based, imidazole-based, carbamic acid metal salts, waxes, and mixtures thereof.

More specifically, the amine-based antioxidants include N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N-phenyl-N'-isopropyl-p-phenylenediamine (3PPD), N,N'-diphenyl-p-phenylenediamine, N,N'-diaryl-p-phenylenediamine, N-phenyl-N'-cyclohexyl p-phenylenediamine, or N- phenyl-N'-octyl-p-phenylenediamine, and the like, and one of these may be used alone or a mixture of two or more thereof may be used.

Phenolic antioxidants include phenolic 2,2'-methylene-bis(4-methyl-6-tert-butylphenol), 2,2'-isobutylidene-bis(4,6-dimethylphenol), or 2 ,6-di-t-butyl-p-cresol, and the like, and one of these may be used alone or a mixture of two or more thereof may be used.

Specifically, the quinoline-based antioxidant includes 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, 6-anilino-2,2,4-trimethyl-1,2-dihydroquinoline, 6-dodecyl-2,2,4-trimethyl-1,2-dihydroquinoline, poly(2,2,4-trimethyl-1,2-dihydroquinoline,

Or poly (2,2,4-trimethyl-1,2-dihydroquinoline (Poly (2,2,4-trimethyl-1,2-dihydroquinoline), RD) and the like, and one of them alone or A mixture of two or more may be used.

As the wax, waxy hydrocarbon or the like may be used.

Among them, N-phenyl-N'-isopropyl-p-phenylenediamine (3PPD), N-(1,3-dimethylbutyl)-N-phenyl-p-phenylenediamine (6PPD), poly(2, Selecting from the group consisting of 2,4-trimethyl-1,2-dihydroquinoline (RD) and mixtures thereof may be more preferable in consideration of the significant improvement effect of the use of the antioxidant.

The antioxidant serves to inhibit oxidation of the rubber composition, and is not particularly limited as long as it has an effect of preventing oxidation of the rubber composition for tires, but N-alkyl-N'-phenyl-para-phenylenediamine, 4,4 '-Bis(alkylamino)triphenylamine, N-isopropyl-N'-phenyl-para-phenylenediamine, N-1,3-dimethylbutyl-N'-phenyl-para-phenylenediamine, 4,4 '-Bis(isopropylamino)-triphenylamine, 4,4'-bis(1,3-dimethylbutylamino)-triphenylamine, 4,4'-bis(1,4-dimethylpentylamino)-tri It is preferably composed of one or two selected from the group consisting of phenylamine, N-alkyl-N'-phenyl-para-phenylenediamine and 4,4'-bis(alkylamino)triphenylamine.

Hereinafter, the present invention will be described in more detail by the following Preparation Examples and Experimental Examples. The following preparation examples and experimental examples are merely examples for carrying out the present invention, and are not intended to limit the protection scope of the present invention.

[Production Example: Preparation of Tire Tread Rubber Composition]

The tire rubber compositions according to Examples and Comparative Examples were prepared according to a conventional tire manufacturing method using the compositions shown in Table 1 below, but are not particularly limited.

division comparative example
One comparative example
2 Example
One Example
2 Example
3 Example
4 Example
5 S-SBR (1) 45 S-SBR (2) 55 112.5 S-SBR (3) 45 45 60 60 60 S-SBR (4) 55 55 55 55 55 BR 15 10 15 15 Silica (1) 95 90 95 95 110 110 120 carbon black 4 4 4 4 4 4 4 TESPT 7.2 7.2 7.2 7.2 8.4 8.4 9.2 Resin 10 10 20 20 30 PVA 5 10 15 15 processing aid 5 5 3 3 3 3 3 process oil 20 15 10 5 5 5 5 zinc oxide 2 2 2 2 2 2 2 stearic acid One One One One One One One Anti-aging agent (6C) 2 2 2 2 2 2 2 DPG 2 2 2.5 2.5 2.5 2.5 2.5 brimstone 1.0 1.0 1.0 1.0 1.0 1.0 1.0 CBS 2.2 2.2 2.2 2.2 2.2 2.2 2.2 super accelerator 0.2 0.2 0.2 0.2 0.2 0.2 0.2

※ S-SBR (1): S-SBR terminal modified with aminosilane without added oil, Tg (glass transition temperature) of about -25 ℃, styrene 26-30%, vinyl content 41-45

S-SBR (2): 37.5 parts by weight of attached oil, Tg (glass transition temperature) including oil is about -36 ° C, styrene is 34 to 38%, vinyl content is 24 to 28. S-SBR

S-SBR (3): S- that has no added oil, has a Tg (glass transition temperature) of about -60 ℃, styrene is 13~17%, and vinyl content is 23~27. SBR

S-SBR (4): 37.5 parts by weight of attached oil, Tg (glass transition temperature) including oil is about -53, styrene is 23-27%, and vinyl content is 18-22. S-SBR

※ 2. BR: Butadiene rubber with Tg (glass transition temperature) of -106 ℃

※ Silica: High Dispersible Silica with nitrogen adsorption of 170 m2/g and CTAB adsorption of 160 m2/g

Carbon Black: N234

※ TESPT: Si69 (Degussa)

※ RESIN : mainly Naphthenic and Aromatic copolymers with a softening point of 95~115 ℃ and a Tg of 25~40 ℃

※ PVA (Polyvinylalcohol): PVA (Polyvinylalcohol) with Tg of -40 to -60 ℃

※ Anti-aging agent (6C): N-1,3-dimethylbutyl-N-phenyl-p-phenylenediamine

※ DPG: Diphenylene guanidine

※ CBS: N-cyclohexyl-2-benzothiazyl sulfenamide

division comparative example
One comparative example
2 Example
One Example
2 Example
3 Example
4 Example
5 Mooney Viscosity (ML1+4) 82 79 83 88 79 76 78 Hardness (ShoreA) 69 68 69 71 71 70 72 300% Modulus 128 115 115 119 110 105 95 breaking energy 185 190 205 212 203 198 196 Wet Grip Index 100 97 101 104 106 107 109 60℃ tan δ 0.125 0.118 0.128 0.132 0.120 0.125 0.131 Lambon Wear Index 100 105 98 97 105 108 113

- Pattern viscosity (ML1+4 (125℃)) was measured according to ASTM standard D1646.

- Hardness was measured according to DIN 53505.

- 300% modulus and breaking energy were measured according to ISO 37 standard.

- For viscoelasticity, G’, G”, and tan δ were measured from -60°C to 60°C under a 10Hz frequency at 0.5% strain using an ARES measuring instrument.

In Table 2, ML1+4 is a value indicating the viscosity of the unvulcanized rubber, and the lower the numerical value, the better the processability of the unvulcanized rubber. Hardness is correlated with steering stability, and the higher the value, the better the steering stability. Breaking energy represents the energy required when rubber breaks. The higher the value, the higher the energy required, so the wear performance is excellent. The Wet Grip Index shows the braking characteristics on a wet road surface, and the higher the number, the better the braking performance. In addition, 60℃ tanδ represents the rotational resistance characteristics, and the lower the numerical value, the better the performance, and the higher the Rambon wear index, the better the wear performance.

From Table 2 above, it can be seen that the breaking energy is improved. In addition, while maintaining 60℃ tan δ or minimizing loss, wet grip index and hardness are improved and maintained or improved in Rambon wear.

As described in detail above, according to the present invention, SSBR with a high functionalization rate is combined with a low Tg SSBR according to the present invention to maximize the interaction with silica, increase the weight part of silica as much as possible within an appropriate level, and resin and water having a glass transition temperature (Tg) above room temperature It is useful for a tread composition with improved wet road braking performance without trade-off of abrasion resistance and low fuel efficiency by applying PVA, a soluble polymer.

Claims (6)

Based on 100 parts by weight of raw rubber;
80 to 120 parts by weight of silica;
5 to 30 parts by weight of resin;
It contains 5 to 30 parts by weight of PVA, which is a water-soluble polymer,
The raw rubber does not contain oil, both ends are modified with an amine system and an amino silane system, the glass transition temperature (Tg) is -70 to -50 ℃, styrene is 13 to 17 wt%, and the vinyl content in butadiene is 23 to 20 to 50 parts by weight of solution-polymerized styrene-butadiene rubber, which is 27% by weight;
Solution-polymerized styrene-butadiene rubber containing oil, terminal-modified with aminosilane, having a glass transition temperature (Tg) of -60 to -40 ° C, 23 to 27 wt% of styrene, and 18 to 22 wt% of vinyl 50 parts by weight;
A rubber composition for a tire tread, comprising:
delete According to claim 1,
The rubber composition for tire tread, characterized in that the silica is highly dispersible silica having a CTAB adsorption of 140 to 280 m ² /g and a hydrogen ion index of 5 to 8 pH.
According to claim 1,
The rubber composition for tire tread, characterized in that the resin has a softening point of 90 to 130 ° C and a glass transition temperature (Tg) of 20 to 90 ° C.
According to claim 1,
The water-soluble polymer PVA has a glass transition temperature (Tg) of 40 to 80 °C and a molecular weight of 10,000 to 50,000.
According to claim 1,
The rubber composition for tire tread further comprises 0 to 40 parts by weight of butadiene rubber and 0 to 20 parts by weight of natural rubber.