KR20230046011A - Rubber composition for tire tread and Tire comprising the rubber composition - Google Patents

Abstract

Disclosed is a rubber composition for a tire tread, comprising butadiene rubber and styrene-butadiene rubber as raw material rubber; silica as a filler; and a resin, wherein the softening point of the resin is 80℃ to 150℃, and tire tread rubber obtained by vulcanizing the rubber composition for a tire tread is in a glass transition state in the entire range of -40℃ to -3℃. The disclosed rubber composition for a tire tread has low braking performance sensitivity to temperature and improved braking performance for all seasons.

Description

Tire tread rubber composition and tire comprising the same {Rubber composition for tire tread and Tire comprising the rubber composition}

It relates to a tire tread rubber composition and a tire comprising the same.

An automobile tire supports a heavy load and is a high-speed rotating object. The tread, which has the greatest influence on the durability of the tire, has a great influence on the driving performance of the tire because it is in contact with the ground.

As the characteristics that tire tread rubber should have, there are steering stability, riding comfort, fuel efficiency, snow performance, abrasion resistance, braking performance, and durability.

One aspect is to provide a tread rubber composition with low sensitivity of braking performance to temperature and improved braking performance for use in all seasons.

Another aspect is to provide a tire made of the rubber composition.

According to one aspect,

butadiene rubber and styrene-butadiene rubber as raw rubber;

silica as a filler; and

A tire tread rubber composition comprising a resin;

The softening point of the resin is 80 ° C to 150 ° C,

The tire tread rubber obtained by vulcanizing the tire tread rubber composition is in a glass transition state in the entire range of -40 ° C to -3 ° C,

A tire tread rubber composition is provided.

According to another aspect,

A tire made of the tire tread rubber composition is provided.

A tire using the tire tread rubber composition according to an embodiment of the present invention shows improved dry braking performance and wet braking performance, and the sensitivity of braking performance to temperature is relatively reduced.

1 is a diagram schematically showing the structure of a tire according to one embodiment.
2 is a graph showing tanδ values according to temperature of tread rubber according to an embodiment.
3 is a graph showing the dynamic modulus E' value according to the temperature of the tread rubber according to one embodiment.

Hereinafter, an exemplary embodiment of a tire tread rubber composition and a tire will be described in more detail.

Since the inventive idea disclosed in this specification can be subjected to various transformations and can have various implementations, specific implementations are described in detail in the detailed description and, if necessary, specific implementations are illustrated in the drawings. Effects and characteristics of the inventive idea of the present specification, and methods for achieving them will become clear with reference to implementations described later in detail together with the drawings. However, the creative idea of the present specification is not limited to the embodiments disclosed below and may be implemented in various forms.

In the following embodiments, terms such as first and second are used for the purpose of distinguishing one component from another, not in a limiting sense.

In the following embodiments, singular expressions include plural expressions unless the context clearly dictates otherwise.

In the following embodiments, terms such as include or have mean that features or elements described in the specification exist, and do not preclude the possibility that one or more other features or elements may be added.

In case an embodiment is otherwise embodied, a specific process sequence may be performed differently from the described sequence. For example, two processes described in succession may be performed substantially simultaneously, or may be performed in an order reverse to the order described.

Hereinafter, if necessary, embodiments of the present invention will be described in detail with reference to the accompanying drawings. do it with

In the drawings, the size of components may be exaggerated or reduced for convenience of explanation. For example, since the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, the inventive ideas disclosed herein are not necessarily limited to those shown.

A tire tread rubber composition according to one embodiment includes butadiene rubber and styrene-butadiene rubber as raw rubber; silica as a filler; And resin; may include. Here, the softening point of the resin may be 80 ℃ to 150 ℃. Tg of the resin may be -29 ℃ to 100 ℃.

Meanwhile, the tire tread rubber obtained by vulcanizing the tire tread rubber composition may be in a glass transition state in the entire range of -40°C to -3°C. For example, tire tread rubber obtained by vulcanizing the tire tread rubber composition may be in a glass transition state in the entire range of -30°C to -3°C.

That is, the tire tread rubber obtained by vulcanizing the tire tread rubber composition may have a glass transition temperature, Tg, in the entire range of -40°C to -3°C. For example, tire tread rubber obtained by vulcanizing the tire tread rubber composition may have a glass transition temperature, Tg, in the entire range of -30°C to -3°C. Therefore, physical properties are different from rubber having a Tg of one point, for example, with a Tg of -29°C.

According to one embodiment of the present invention, the styrene butadiene rubber may include solution polymerized styrene butadiene rubber (SSBR). For example, the styrene-butadiene rubber may include two different types of solution polymerized styrene-butadiene rubber (SSBR).

According to one embodiment of the present invention, the styrene-butadiene rubber is solution polymerized styrene-butadiene rubber (SSBR) A having a styrene:vinyl ratio of 30:70 to 70:30; and solution polymerized styrene-butadiene rubber (SSBR) B having a styrene:vinyl ratio of 10:30 to 30:10. The styrene:vinyl ratio means the ratio of the number of styrene functional groups to the number of vinyl functional groups in the polymer chain.

For example, the ratio of styrene:vinyl of solution polymerized styrene-butadiene rubber (SSBR) A may be 30:65 to 45:30. For example, the ratio of styrene:vinyl of solution polymerized styrene-butadiene rubber (SSBR) A may be 30:45 to 35:55.

For example, the ratio of styrene:vinyl of solution polymerized styrene-butadiene rubber (SSBR) B may be 10:30 to 20:12. For example, the ratio of styrene:vinyl of solution polymerized styrene-butadiene rubber (SSBR) B may be 12:25 to 15:15.

When the ratio of styrene:vinyl in the solution polymerized styrene butadiene rubber (SSBR) B and the solution polymerized styrene butadiene rubber (SSBR) A is in the above range, the Tg of the vulcanized tread rubber composition has the above range.

According to one embodiment of the present invention, the raw rubber of the tire trad composition may consist of butadiene rubber and the styrene-butadiene rubber. The butadiene rubber may not be high-cis butadiene rubber but may be general butadiene rubber having a Tg of about -100°C.

Meanwhile, the tire tread composition may further include, for example, at least one selected from isoprene-containing styrene butadiene rubber, nitrile-containing styrene butadiene rubber, neoprene rubber, chlorobutyl rubber, and bromobutyl rubber as a raw material rubber.

In addition, the rubber composition may further include natural rubber as a raw material rubber in addition to synthetic rubber. The natural rubber may be general natural rubber or modified natural rubber.

As the general natural rubber, any known natural rubber may be used, and the country of origin is not limited. The natural rubber mainly includes cis-1,4-polyisoprene, but may also include trans-1,4-polyisoprene according to required properties. Therefore, in addition to natural rubber containing cis-1,4-polyisoprene as a main component, natural rubber containing trans-1,4-isoprene as a main component, such as balata, a kind of rubber of the Sapotaceae family from South America, Rubber may also be included.

The modified natural rubber refers to a product obtained by modifying or refining the general natural rubber. For example, examples of the modified natural rubber include epoxidized natural rubber (ENR), deproteinized natural rubber (DPNR), and hydrogenated natural rubber.

According to one embodiment of the present invention, the content of the solution polymerized styrene butadiene rubber (SSBR) B may be 1.5 to 2.8 times the content of the solution polymerized styrene butadiene rubber (SSBR) A.

For example, based on 100 parts by weight of raw rubber, the content of the solution polymerized styrene butadiene rubber (SSBR) A may be 15 to 30 parts by weight, and the content of the solution polymerized styrene butadiene rubber (SSBR) B is 30 to 60 parts by weight part, and the content of the butadiene rubber may be 15 to 25 parts by weight.

In the raw rubber, the content of solution polymerized styrene butadiene rubber (SSBR) A, solution polymerized styrene butadiene rubber (SSBR) B, and butadiene rubber must satisfy the above range so that the Tg of the vulcanized tread rubber composition has the above range.

According to one embodiment of the present invention, the rubber composition may further include a filler, for example, silica and/or carbon black. Preferably, the rubber composition may include only silica as a filler.

As the silica, any generally known silica may be used, and for example, commercially available Z-175, HD-165GR, US7000GR or 9000GR may be used.

According to one embodiment of the present invention, the content of the silica may be 30 to 90 parts by weight based on 100 parts by weight of the raw rubber. When the silica content is within the above range, the physical properties of the tread rubber are optimal.

The silica may have a nitrogen adsorption specific surface area per gram (N ₂ SA) of 100 to 180 m ² /g and a cetyl trimethyl ammonium bromide (CTAB) adsorption specific surface area of 110 to 170 m ² /g, The present invention is not limited thereto.

If the nitrogen adsorption specific surface area of the silica is less than 100 m ² /g, reinforcing performance by the silica filler may be disadvantageous, and if it exceeds 180 m ² /g, processability of the rubber composition may be disadvantageous. In addition, if the CTAB adsorption specific surface area of the silica is less than 110 m ² /g, the reinforcing performance of the silica filler may be disadvantageous, and if it exceeds 170 m ² /g, the processability of the rubber composition may be disadvantageous.

According to one embodiment of the present invention, the tread rubber composition may include silica and a coupling agent. The coupling agent may be for enhancing the dispersion of silica. Meanwhile, the coupling agent may not be included depending on the silica content.

The coupling agent may be, for example, a silane coupling agent. The silane coupling agent is a coupling agent containing Si, and the silane coupling agent reduces the polarity of silica by bonding to OH of silica so that it is well mixed with rubber. Any silane coupling agent commonly used in the field to which the present invention pertains may be used.

According to one embodiment of the present invention, the content of the coupling agent may be 5 to 11 parts by weight based on 100 parts by weight of raw rubber. Considering the content of the raw rubber and the content of silica, when the content of the coupling agent is within the above range, the processing of the rubber composition is smooth and the physical properties of the crosslinked rubber are optimal.

The carbon black may have a nitrogen adsorption specific surface area per gram (N ₂ SA) of 30 to 300 m ² /g and an oil absorption of n-dibutyl phthalate (DBP) of 60 to 180 cc/100 g, but the present invention This is not limited to this.

If the nitrogen adsorption specific surface area of the carbon black exceeds 300 m ² /g, processability of the rubber composition for a tire may be disadvantageous, and if it is less than 30 m ² /g, reinforcing performance by carbon black as a filler may be disadvantageous. In addition, if the DBP oil absorption amount of the carbon black exceeds 180 cc/100 g, the processability of the rubber composition may deteriorate, and if the DBP oil absorption amount is less than 60 cc/100 g, reinforcing performance by carbon black as a filler may deteriorate.

Representative examples of the carbon black are N110, N121, N134, N220, N231, N234, N242, N293, N299, S315, N326, N330, N332, N339, N343, N347, N351, N358, N375, N539, N550, N582 , N630, N642, N650, N683, N754, N762, N765, N774, N787, N907, N908, N990 or N991.

The carbon black may be included in, for example, 3 to 20 parts by weight, for example, 5 to 15 parts by weight, based on 100 parts by weight of the raw rubber.

According to one embodiment of the present invention, the resin may be an alpha methyl stylene (AMS)-based glass transition state resin.

According to one embodiment of the present invention, the softening point of the AMS (alph methyl stylene)-based resin may be 85 ° C to 120 ° C.

In the present specification, "softening point" means a temperature at which a resin starts to deform when a constant load is applied and heated at a constant temperature increase rate.

In the case of including an AMS-based resin having a softening point in the range of 85° C. to 120° C., the content of the AMS-based resin may be 25 to 60 parts by weight based on 100 parts by weight of raw rubber.

As an AMS-based resin, when the softening point and content are within the above ranges, the broadness of the vulcanized tread rubber composition Tg can be adjusted, and thus the Tg can be within the above ranges.

According to one embodiment of the present invention, the resin is a hydrogenated DCPD (dicyclopentadiene) -C9 copolymer resin, a DCPD (dicyclopentadiene) resin, a terpene phenolic resin, a C5-C9 copolymer resin, in addition to the AMS-based resin. polymer resins, or any combination thereof.

For example, the resin of the tire tread rubber composition according to one embodiment of the present invention includes hydrogenated DCPD (dicyclopentadiene) -C9 copolymer resin, DCPD (dicyclopentadiene) resin, terpene phenolic resin, C5 -C9 copolymer resin, or any combination thereof.

In this case, the hydrogenated DCPD (dicyclopentadiene) -C9 copolymer resin, DCPD (dicyclopentadiene) resin, terpene phenolic resin, C5-C9 copolymer resin, or any combination thereof The softening point of the resin may be 100°C to 140°C.

The content of the resin comprising the hydrogenated DCPD (dicyclopentadiene) -C9 copolymer resin, DCPD (dicyclopentadiene) resin, terpene phenolic resin, C5-C9 copolymer resin, or any combination thereof Silver may be 25 to 60 parts by weight based on 100 parts by weight of raw rubber.

As a resin comprising the hydrogenated DCPD (dicyclopentadiene) -C9 copolymer resin, DCPD (dicyclopentadiene) resin, terpene phenolic resin, C5-C9 copolymer resin, or any combination thereof, the softening point And when the content is within the above range, the broadness of the vulcanized tread rubber composition Tg can be adjusted, so that the Tg can have the above range.

For example, the DCPD (dicyclopentadiene) resin may include a repeating unit represented by Formula 1 below:

<Formula 1>

In Formula 1, n may be 7 to 45.

For example, the terpene phenolic resin may include a modified terpene phenol resin, a polyterpene resin, a rosin resin, or a modified rosin resin.

For example, the modified terpene phenol resin may include a repeating unit represented by Formula 2 as a polymer of terpene and phenol:

<Formula 2>

In Formula 2, m may be 7 to 30.

The tire tread rubber composition may optionally further include various additives such as additional vulcanization agents, vulcanization accelerators, vulcanization accelerators, anti-aging agents, antioxidants, or softeners. Any of the above various additives may be used as long as they are commonly used in the field to which the present invention belongs, and their contents are not particularly limited as they depend on the mixing ratio used in conventional tire tread rubber compositions.

As the vulcanizing agent, a sulfur-based vulcanizing agent can be preferably used. 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), tetraethyl Organic vulcanizers such as tetraethyltriuram disulfide (TETD) and dithiodimorpholine may be used. As the sulfur vulcanizing agent, elemental sulfur or a vulcanizing agent that produces sulfur, for example, amine disulfide, polymeric sulfur, etc. may be used.

The vulcanizing agent is preferably included in an amount of 0.5 to 10.0 parts by weight based on 100 parts by weight of the raw rubber in that the raw rubber is less sensitive to heat and chemically stable as a proper vulcanizing effect.

The vulcanization accelerator refers to an accelerator that accelerates the vulcanization rate or promotes a delaying action in the initial vulcanization step.

The vulcanization accelerators include sulfenamide-based, thiazole-based, thiuram-based, thiourea-based, guanidine-based, dithiocarbamic acid-based, aldehyde-amine-based, aldehyde-ammonia-based, imidazoline-based, xanthate-based and these Any one selected from the group consisting of combinations may be used.

Examples of the sulfenamide-based vulcanization accelerator include N-cyclohexyl-2-benzothiazylsulfenamide (CBS), N-tert-butyl-2-benzothiazylsulfenamide (TBBS), N,N-dicyclohexyl Any one selected from the group consisting of -2-benzothiazylsulfenamide, N-oxydiethylene-2-benzothiazylsulfenamide, N,N-diisopropyl-2-benzothiazolesulfenamide, and combinations thereof A sulfenamide-based compound of can be used.

Examples of the thiazole-based vulcanization accelerator include 2-mercaptobenzothiazole (MBT), dibenzothiazyl disulfide (MBTS), sodium salt of 2-mercaptobenzothiazole, and zinc salt of 2-mercaptobenzothiazole. , copper salt of 2-mercaptobenzothiazole, cyclohexylamine salt of 2-mercaptobenzothiazole, 2-(2,4-dinitrophenyl)mercaptobenzothiazole, 2-(2,6-di Any one thiazole-based compound selected from the group consisting of ethyl 4-morpholinothio)benzothiazole and combinations thereof may be used.

Examples of the thiuram-based vulcanization accelerator include tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram disulfide, dipentamethylenethiuram monosulfide, dipentamethylene Any one thiuram-based compound selected from the group consisting of thiuram tetrasulfide, dipentamethylenethiuram hexasulfide, tetrabutylthiuram disulfide, pentamethylenethiuramtetrasulfide, and combinations thereof may be used.

The thiourea-based vulcanization accelerator is, for example, any one thiourea-based selected from the group consisting of thiacarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea, diortotolylthiourea, and combinations thereof compound can be used.

As the guanidine-based vulcanization accelerator, for example, any one guanidine-based compound selected from the group consisting of diphenylguanidine, diortolylguanidine, triphenylguanidine, orthotolylbiguanide, diphenylguanidine phthalate, and combinations thereof may be used. can

Examples of the dithiocarbamic acid-based vulcanization accelerator include zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, Zinc dibutyldithiocarbamate, zinc diamyldithiocarbamate, zinc dipropyldithiocarbamate, complex salts of zinc pentamethylenedithiocarbamate and piperidine, zinc hexadecylisopropyldithiocarbamate, octadecyl Zinc isopropyldithiocarbamate, Zinc dibenzyldithiocarbamate, Sodium diethyldithiocarbamate, Piperidine pentamethylenedithiocarbamate, Selenium dimethyldithiocarbamate, Tellurium diethyldithiocarbamate, Diethyldithiocarbamate Any one dithiocarbamate-based compound selected from the group consisting of cadmium dithiocarbamate and combinations thereof may be used.

The aldehyde-amine-based or aldehyde-ammonia-based vulcanization accelerator is, for example, an aldehyde selected from the group consisting of acetaldehyde-aniline reactants, butyraldehyde-aniline condensates, hexamethylenetetramine, acetaldehyde-ammonia reactants, and combinations thereof - Amine-based or aldehyde-ammonia-based compounds may be used.

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

The vulcanization accelerator may be included in an amount of 0.5 to 4.0 parts by weight based on 100 parts by weight of the raw rubber in order to maximize productivity enhancement and improvement of rubber properties through acceleration of vulcanization rate.

The vulcanization accelerator is a compounding agent used in combination with the vulcanization accelerator to completely promote the effect, and any one selected from the group consisting of inorganic vulcanization accelerators, organic vulcanization accelerators, and combinations thereof may be used. .

As the inorganic vulcanization accelerator, any one selected from the group consisting of zinc oxide (ZnO), zinc carbonate, magnesium oxide (MgO), lead oxide, potassium hydroxide, and combinations thereof can be used. there is. The organic vulcanization accelerator is selected from the group consisting of stearic acid, zinc stearate, palmitic acid, linoleic acid, oleic acid, lauric acid, dibutyl ammonium oleate, derivatives thereof, and combinations thereof Any one of them can be used.

In particular, as the vulcanization accelerator, the zinc oxide and the stearic acid may be used together. In this case, the zinc oxide is dissolved in the stearic acid to form an effective complex with the vulcanization accelerator, thereby removing advantageous sulfur during the vulcanization reaction. By making it, it facilitates the crosslinking reaction of rubber.

When the zinc oxide and the stearic acid are used together, they may be used in amounts of 1 to 10 parts by weight and 0.5 to 3 parts by weight, respectively, based on 100 parts by weight of the raw rubber, in order to serve as an appropriate vulcanization accelerator. When the contents of the zinc oxide and the stearic acid are less than the above range, the vulcanization rate is slow and productivity may decrease. When the content exceeds the above range, a scorch phenomenon may occur and physical properties may be deteriorated.

The softener is added to a rubber composition to facilitate processing by imparting plasticity to rubber or to reduce the hardness of vulcanized rubber, and refers to oils and other materials used in rubber compounding or rubber manufacturing. The softening agent refers to processing oil or oils included in other rubber compositions. As the softening agent, any one selected from the group consisting of petroleum oil, vegetable oil, and combinations thereof may be used, but the present invention is not limited thereto.

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

Representative examples of the paraffinic oil include P-1, P-2, P-3, P-4, P-5, and P-6 of Michang Oil Co., Ltd., and a representative example of the naphthenic oil is Michang Oil. and N-1, N-2, and N-3 of Michang Oil Co., Ltd., and A-2 and A-3 of Michang Oil Co., Ltd. as representative examples of the aromatic oil.

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

In particular, the oil used as the softener has a total content of PAHs of 3% by weight or less and a kinematic viscosity of 95 or more (15 to 25% by weight of aromatic components and 27 to 37% by weight of naphthenic components in the 210 μ softener). A TDAE oil having 38 to 58% by weight of paraffinic components by weight can be preferably used.

The TDAE oil improves the low-temperature characteristics and fuel efficiency of the tire including the TDAE oil, but also has advantageous properties against environmental factors such as the possibility of PAHs causing cancer.

The plant 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 , jojoba oil, macadamia nut oil, safflower oil, tung oil, and any one selected from the group consisting of combinations thereof may be used.

The softening agent is preferably used in an amount of 0 to 10 parts by weight based on 100 parts by weight of the raw rubber in view of improving processability of the raw rubber.

According to one embodiment of the present invention, the tread rubber composition may not include a softening agent, for example, oil.

The antioxidant is an additive used to stop a chain reaction in which a tire is automatically oxidized by oxygen. As the anti-aging agent, any one selected from the group consisting of amine-based, phenol-based, quinoline-based, imidazole-based, carbamic acid metal salts, waxes, and combinations thereof may be appropriately selected and used.

Examples of the amine-based antioxidant include N-phenyl-N'-(1,3-dimethyl)-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, N,N'-diaryl-p-phenylenediamine, N-phenyl-N' Any one selected from the group consisting of -cyclohexyl p-phenylenediamine, N-phenyl-N'-octyl-p-phenylenediamine, and combinations thereof may be used. The phenolic antioxidants include phenolic 2,2'-methylene-bis(4-methyl-6-tert-butylphenol), 2,2'-isobutylidene-bis(4,6-dimethylphenol), 2 Any one selected from the group consisting of ,6-di-t-butyl-p-cresol and combinations thereof may be used. As the quinoline-based antioxidant, 2,2,4-trimethyl-1,2-dihydroquinoline and derivatives thereof may be used, specifically 6-ethoxy-2,2,4-trimethyl-1,2-di consisting of hydroquinoline, 6-anilino-2,2,4-trimethyl-1,2-dihydroquinoline, 6-dodecyl-2,2,4-trimethyl-1,2-dihydroquinoline, and combinations thereof. Any one selected from the group can be used. As the wax, waxy hydrocarbon may be preferably used.

The anti-aging agent should have high solubility in rubber in addition to anti-aging action, should have low volatility, be inactive with respect to rubber, and should not inhibit vulcanization, 1 to 10 parts by weight of the raw rubber It may be included in parts by weight.

A typical amount of the antioxidant may be included, for example, from about 1 to about 5 parts by weight. Representative antioxidants include, but are not limited to, for example diphenyl-p-phenylenediamine and others.

Referring to FIG. 1 , a tire 10 includes a tread part 100 , a sidewall part 200 and a bead part 300 .

The tread portion 100 is a portion in contact with the ground in cross section, and serves to protect the tire from impact and trauma from the road surface. A plurality of blocks partitioned by grooves may be formed on the surface of the tread portion as described above to improve drainage of the tire.

The rubber composition according to one embodiment of the present invention is included in the tread.

The sidewall 200 and the bead portion 300 are sequentially positioned on both sides of the tread portion along the width direction of the tire.

The sidewall 200 is a part extending from both ends of the tread to form the side surface of the tire, and serves to withstand repeated contraction and expansion while driving and to protect the carcass layer 400 located on the inner surface. do

The bead part 300 is provided at both ends of the sidewall 200 to surround the end of the cord paper, and the bead part 300 includes a bead core 500 including a ring-shaped steel wire.

The carcass layer 400 is located between the left and right pair of bead parts 300, and is bonded to the tire rubber sheet inside the tire to form the skeleton of the tire. ) from the inside of the tire to the outside.

An inner liner 700 is located on one side of the inside of the carcass layer 400 and serves to prevent air inside the tire from escaping to the outside.

On the outer surface of the carcass layer 400 located on the tread part 100, a belt layer 600 is positioned as a reinforcing layer to increase the elasticity of the tread and to have maneuverability and stability.

The belt layer rubber may include a cobalt compound, and the cobalt compound includes cobalt salt, cobalt-boron ester, organic cobalt salt, inorganic cobalt salt, non-cobalt salt, etc. As the adhesive system, cobalt salt alone, cobalt- In addition to RH, cobalt-HRH, resin [e.g., methylene acceptor: phenolic, resorcinol-based, cresol-based, etc., or donor: hexamethylenetetraamine (HMT), hexamethoxymethylmelamine (HMMA), pentamethoxymethyl melamine (PMMA)] and the like.

In general, in order to improve adhesion, the adhesive system of adhesive compounded rubber is improved (cobalt-RH, cobalt-HRH, and their modified systems), resins used as adhesive aids are improved and performance is improved, cobalt salts used as adhesive aids are improved, and adhesion Improvement of rubber vulcanization system, use of new compound composition (reinforcement, carbon black, silica, polymer, chemicals), etc. are being used.

The content of the cobalt compound may include 0.2 to 5.0 parts by weight based on 100 parts by weight of raw rubber, but is not limited thereto.

A cap ply 800 including a hybrid cord may be disposed between the belt layer 600 and the tread portion 100 . The cap ply 800 can maintain the performance of the tire by suppressing the flow of the belt layer 600 during driving.

The tire tread rubber composition may be prepared through a conventional two-step continuous manufacturing process. That is, during the first step (non-productive step) of thermomechanical treatment or kneading at a maximum temperature ranging from 110 to 190 ° C., preferably from 135 to 160 ° C., and during the finishing step in which the crosslinking system is mixed, typically 110 It can be prepared in a suitable mixer using a second step (productive step) of mechanical treatment at a low temperature of less than ° C, for example, 40 to 100 ° C, but is not limited thereto.

A tire according to another embodiment of the present invention includes using the tire tread rubber composition when forming a green tire. As a method of forming a green tire using the tire tread rubber composition, any method conventionally used for manufacturing tires can be applied, and thus a detailed description thereof will be omitted herein.

1 illustrates a tire for a passenger car, but is not limited thereto, and may be a tire for a passenger car, a tire for racing, an airplane tire, a tire for agricultural machinery, an off-the-road tire, a truck tire, or a bus tire. there is. Also, the tire may be a radial tire or a bias tire, and is preferably a radial tire.

The present invention is explained in more detail through the following Examples and Comparative Examples. However, the examples are for exemplifying the present invention, and the scope of the present invention is not limited only thereto.

Example 1 and Comparative Example 1

Each of the components in Table 1 below was added to a Banbury mixer in the ratios (unit: parts by weight) and mixed. After all ingredients were added to a tangential type Banbury mixer, the ratio of each ingredient was adjusted so that the fill factor of 1.65L capacity was 0.65 to 0.70.

division Comparative Example 1 Example 1 SSBR-1 ¹⁾ 54 - SSBR-A ²⁾ 21 21 SSBR-B ³⁾ - 54 BR 25 25 Silica ⁴⁾ 80 80 oil ⁵⁾ 30 - Resin ⁶⁾ - 30 zinc oxide 2.0 2.0 Accelerator ⁷⁾ 3.0 3.0 sulfur 1.1 1.1

1) styrene: vinyl = 22 ~ 28 : 22 ~ 28

2) styrene: vinyl = 30 ~ 45 : 30 ~ 65

3) styrene: vinyl = 10 ~ 20 : 12 ~ 30

4) EVONIK, HD-165GR

5) RAE

6) AMS resin: softening point 85 ~ 120℃

7) N,N-Dicyclohexyl-2-benzothiazolesulfenamide

evaluation example

Evaluation of properties of vulcanized rubber

Rubber sheets made of the rubber compositions of Comparative Example 1 and Example 1 were vulcanized at 165° C. for 10 minutes in a vulcanizer to prepare specimens. Physical properties such as hardness and tensile strength were evaluated for each specimen. The results are shown in Table 2 below.

HD (hardness)

Using a Shore A-type durometer, one specimen was measured a total of 5 times on a smooth surface with a thickness of 6 mm or more and a diameter of 10 mm or more according to ASTM D2240-97, and the average value was determined.

Tensile properties

Tensile strength of the crosslinked specimen was measured using a tensile tester (INSTRON) according to ASTM D412. The specimen for measurement was manufactured in a sheet form using a hydraulic press and produced in a dumbbell form using a specimen cutter. As for the test conditions, the tensile speed was measured at 500 mm/min at room temperature. Tensile strength (T/S) is a value representing the stress value until the test piece breaks in the tensile tester, and the force received per unit area is measured.

elongation

Elongation was measured by a method of expressing the strain value in % until the test piece breaks in a tensile tester.

Wet road friction coefficient

RTM Friction Tester (UESHIMA Co., can evaluate the friction characteristics of tire tread compounds in dry, wet and ice conditions.) Measured with equipment, the higher the friction coefficient value (μ), the better)

dynamic characteristics

Viscoelasticity as a dynamic characteristic was measured for Tanδ values from -70 ° C to 70 ° C under a 10 Hz frequency at 0.2% strain using a Gabo viscometer. At this time, the temperature with the largest Tanδ value is defined as the glass transition temperature, and the larger the Tanδ value at 0 ° C, the better the wet braking performance, and the larger the Tanδ value at 25 ° C, the better the dry braking performance.

The evaluation results are shown in Table 2 below.

Comparative Example 1 Example 1 Hardness 72 71 300% modulus (kg/cm ² ) 102 105 Tensile strength (kg/cm ² ) 176 231 elongation 460 550 Wet road friction coefficient 0.430 0.460 Tg(℃) -29 -29 to -5 0℃ tanδ 0.380 0.396 25℃ tanδ 0.239 0.308

From the results of Table 2, it can be seen that Example 1 and Comparative Example 1 show similar results in physical properties such as hardness and 300% modulus.

It can be seen that physical properties such as tensile strength and elongation of Example 1 are superior to those of Comparative Example 1.

On the other hand, while Comparative Example 1 has a Tg of -29 ° C, Example 1 has a Tg in a wide range of -29 to -5 ° C, which improves wet braking performance and dry braking performance. It can be seen.

Meanwhile, the tan δ values of the tread rubbers of Example 1 and Comparative Example 1 according to temperature were measured and shown in FIG. 2 .

Referring to FIG. 2, Comparative Example 1 has a clear peak around -29 ° C, but Example 1 has a peak that is relatively insignificant enough to say that the range from -29 to 10 ° C is the maximum peak point.

This means that the tread rubber vulcanized with the tread rubber composition according to one embodiment of the present invention contains a Tg comparable to the braking performance of the summer compound (Tg: around -10 ° C), so that the braking performance can be improved in all seasons. means there is

Meanwhile, values of dynamic modulus E′ according to temperature of the tread rubbers of Example 1 and Comparative Example 1 were measured and shown in FIG. 3 .

Referring to FIG. 3 , it can be seen that the slope of Example 1 is gentler than that of Comparative Example 1. A gentle slope in the graph of the dynamic modulus E' with temperature means that the braking sensitivity does not change well with temperature.

Therefore, it can be seen that the braking sensitivity of the tread rubber vulcanized with the tread rubber composition according to one embodiment of the present invention does not change better than that of Comparative Example 1 according to temperature.

Accordingly, it can be seen that the tire made of the tire tread rubber composition according to one embodiment of the present invention has little change in braking performance during the four seasons.

Although the above has been described with reference to embodiments, those skilled in the art to variously modify and modify the present invention within the scope not departing from the spirit and scope of the present invention described in the claims of the present invention. You will understand that it can be changed.

10: tire
100: tread part
200: side wall
300: bead part
400: carcass layer
500: bead core
600: belt layer
700: inner liner
800: cap ply

Claims (10)

butadiene rubber and styrene-butadiene rubber as raw rubber;
silica as a filler; and
A tire tread rubber composition comprising a resin;
The softening point of the resin is 80 ° C to 150 ° C,
The tire tread rubber obtained by vulcanizing the tire tread rubber composition is in a glass transition state in the entire range of -40 ° C to -3 ° C,
A tire tread rubber composition. According to claim 1,
The tire tread rubber composition of claim 1, wherein the styrene butadiene rubber comprises solution polymerized styrene butadiene rubber (SSBR). According to claim 1,
The tire tread rubber composition of claim 1 , wherein the styrene butadiene rubber comprises two different types of solution polymerized styrene butadiene rubber (SSBR). According to claim 1,
The styrene butadiene rubber
solution polymerized styrene-butadiene rubber (SSBR) A having a styrene:vinyl ratio of 30:70 to 70:30; and
A solution polymerized styrene butadiene rubber (SSBR) B having a styrene:vinyl ratio of 10:30 to 30:10;
A tire tread rubber composition. According to claim 4,
The tire tread rubber composition of claim 1 , wherein the content of the solution polymerized styrene butadiene rubber (SSBR) B is 1.5 to 2.8 times the content of the solution polymerized styrene butadiene rubber (SSBR) A. According to claim 1,
The tire tread rubber composition, wherein the resin is an alpha methyl stylene (AMS)-based resin. According to claim 6,
The tire tread rubber composition, wherein the AMS (alph methyl stylene)-based resin has a softening point of 85 ° C to 120 ° C. According to claim 1,
The resin comprises hydrogenated DCPD (dicyclopentadiene) -C9 copolymer resin, DCPD (dicyclopentadiene) resin, terpene phenolic resin, C5-C9 copolymer resin, or any combination thereof, A tire tread rubber composition. According to claim 8,
The softening point of the resin comprising the hydrogenated DCPD (dicyclopentadiene) -C9 copolymer resin, DCPD (dicyclopentadiene) resin, terpene phenolic resin, C5-C9 copolymer resin, or any combination thereof A tire tread rubber composition of 100°C to 140°C. A tire made of the tire tread rubber composition of claim 1.

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