KR102097075B1 - Rubber composition for tire sidewall and Tire comprising same - Google Patents

Abstract

Raw rubber including natural rubber and synthetic rubber derived from diene monomer; And a rubber composition for a tire sidewall comprising wax A having a maximum carbon molecular weight distribution of 31 to 38 and wax B having a maximum carbon molecular weight distribution of 25 to 30, and a cured tire comprising the composition.

Description

Rubber composition for tire sidewall and tire comprising same {}

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

As a sidewall of the tire, elasticity is required, and waxes and amine-based anti-aging agents are used to prevent aging caused by ozone. On the other hand, when a wax and an amine-based anti-aging agent are used in the rubber composition, the wax and the amine-based anti-aging agent may exude excessively to the tire surface over time to cause problems.

One aspect is to provide a rubber composition for tire sidewalls with no blooming and high gloss.

Another aspect is that the sidewall of the tire obtained by vulcanizing the rubber composition exhibits high gloss.

According to one aspect,

Raw rubber including natural rubber and synthetic rubber derived from diene monomer; And

A rubber composition for a tire sidewall comprising wax A having a maximum carbon molecular weight distribution of 31 to 38 and wax B having a maximum carbon molecular weight distribution of 25 to 30 is provided.

According to the other aspect,

A tire comprising a sidewall obtained by vulcanizing the rubber composition for sidewalls is provided.

According to one aspect, a raw rubber including natural rubber and synthetic rubber derived from diene monomers; And a tire having a maximum carbon molecular weight distribution of 31 to 38 and a wax composition having a maximum carbon molecular weight distribution of 25 to 30, wherein the tire is made of a green tire including a rubber composition for a sidewall of a tire in a sidewall region, over time. Accordingly, the wax moved to the surface can be polished without causing blooming, and the tire appearance can be improved without using a brightener.

1 is a view schematically showing the structure of a tire according to an embodiment.
Figure 2 is a photograph showing the surface of the specimen obtained by vulcanizing the sidewall rubber composition.

Hereinafter, a rubber composition for a tire sidewall and an tire including the same will be described in more detail in an exemplary embodiment.

The creative idea disclosed in the present specification may apply various transformations and may have various implementations, so that specific implementations are described in detail in the detailed description, and specific implementations are illustrated in the drawings as necessary. Effects and features of the creative ideas of the present specification, and a method of achieving them will be clarified with reference to embodiments described below in detail together with the drawings. However, the creative spirit 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 other components, not limited meanings.

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

In the following embodiments, terms such as include or have mean that a feature or component described in the specification is present, and does not preclude the possibility that one or more other features or components may be added.

When one embodiment can be implemented differently, a specific process order may be performed differently from the described order. For example, two processes described in succession may be performed substantially simultaneously, or may be performed in an order opposite to that described.

Hereinafter, if necessary, embodiments of the present invention will be described in detail with reference to the accompanying drawings, and the same or corresponding components will be given the same reference numerals when described with reference to the drawings, and overlapping descriptions thereof will be omitted. Shall be

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

Paraffins of saturated hydrocarbons of long chain form are called normal paraffins, and paraffins of saturated hydrocarbons containing branches are called isoparaffins. If the molecular weights of paraffins are the same, the radius of normal paraffins is greater than that of isoparaffins. This is because normal paraffin is longer than isoparaffin, and thus the radius of rotation of the molecule is large.

The movement of wax without chemical bonding in the rubber elastic body crosslinked in three dimensions is basically caused by diffusion, although temperature affects. Factors related to the diffusion rate include molecular weight and molecular radius. Since the 3D space moves and moves, if the size is large, it can act as one factor that slows the movement speed. When the molecule moves, the rotational motion also moves together, so the movement speed may be relatively slow when the length is long.

Blooming (blooming) refers to the increase in concentration on the surface due to the movement of the compound inside the rubber. Blooming is related to compounds such as sulfur, wax, and preservatives. Over time, the compounds that have diffused to the surface form crystals again, or the result of reaction with oxygen in the atmosphere affects product appearance. Can be crazy.

In the case of wax, the surface of the tire (for example, the sidewall) becomes white, causing whitening, and a problem that degrades the appearance of the black tire.

Meanwhile, the evaluation of the appearance of the tire is mainly on the sidewall portion. Since the tread is in contact with the ground, it does not play an important role in the evaluation of appearance. On the other hand, a separate varnish may be applied to the purchased tires for side polish, but it is impossible to use an appropriate amount, which adversely affects tire life.

Rubber composition for a tire sidewall according to an embodiment of the present invention includes a natural rubber, and a raw rubber comprising a synthetic rubber derived from a diene monomer; And wax A having a maximum carbon molecular weight distribution of 31 to 38 and wax B having a maximum carbon molecular weight distribution of 25 to 30.

Waxes are ester-based and paraffin-based, and the wax A and wax B included in the rubber composition for a tire sidewall according to an embodiment of the present invention are paraffin-based waxes.

Paraffin wax is a saturated hydrocarbon compound and is an alkane compound composed of only carbon and hydrogen. Generally, the number of carbon atoms in the wax is 20 or more and is solid at room temperature.

The rubber composition for tire sidewalls according to an embodiment of the present invention has a maximum carbon molecular weight distribution in the case of wax A as described above, the proportion of normal paraffin is 50 to 70%, and the proportion of iso paraffin is 30 to 50%, maximum In the case of wax B having a carbon molecular weight distribution as described above, the ratio of normal paraffin may be 70 to 85%.

For example, the maximum carbon molecular weight distribution of the wax A is 33 to 35, the ratio of normal paraffin is 55 to 65%, and the ratio of iso paraffin is 34 to 45%. For example, the maximum carbon molecular weight distribution of the wax B is 27 to 29, and the ratio of normal paraffin is 73 to 83%.

When the maximum carbon molecular weight distribution of each of wax A and wax B, the ratio of normal paraffin and the ratio of isoparaffin are within the above ranges, blooming suppression and glossiness are optimal.

According to an embodiment of the present invention, the content of the wax A may be 1.0 to 1.7 parts by weight, and the content of the wax B may be 0.3 to 1.7 parts by weight. On the other hand, in the relationship between wax A and B, the ratio of the weight part of the wax A to the weight part of the wax B is preferably 0.59 to 5.7. When the content of wax A is applied equal to or more than the content of wax B, the glossiness can be increased. For example, a ratio of parts by weight of the wax A to parts by weight of the wax B may be 1 to 3.

Wax A, which has a relatively larger molecular weight distribution than wax B, has some form of isomer in the molecule, so migration over the tire surface is uniform over time.

According to one embodiment of the present invention, the rubber composition may include natural rubber as a raw rubber. The natural rubber may be a general natural rubber or a modified natural rubber.

The general natural rubber may be any of those known as natural rubber, and the origin and the like are not limited. The natural rubber contains cis-1,4-polyisoprene as a main body, but may also include trans-1,4-polyisoprene depending on the required characteristics. Therefore, in addition to natural rubber containing cis-1,4-polyisoprene as a main body, natural rubber containing trans-1,4-isoprene as a main body, such as Valata, which is a kind of rubber from the South American sapota family, is mainly used as the main rubber. Rubber may also be included.

The modified natural rubber means that the general natural rubber is modified or purified. For example, the modified natural rubber includes epoxidized natural rubber (ENR), deproteinized natural rubber (DPNR), hydrogenated natural rubber, and the like.

Natural rubbers include various forms thereof, such as pale crepe and smoked sheet, and balata and gutta percha. The rubber may be only natural rubber or may be a blend of natural rubber and synthetic rubber. Synthetic polymers are derived from diene monomers and include polymers (homopolymers) made from single monomers or mixtures (copolymers) of two or more copolymerizable monomers in which monomers are combined in random distribution or block form. The monomer may or may not be substituted, may have one or more double bonds, conjugated dienes and non-conjugated dienes, and monoolefins including cyclic monoolefins and non-cyclic mono olefins, particularly vinyl and vinylidene monomers. have. Examples of conjugated dienes include 1,3-butadiene, isoprene, chloroprene, 2-ethyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene and piperylene. Examples of non-conjugated dienes include 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, dicyclopentadiene, 1,5-cyclooctadiene and ethyldiene norbornene. Examples of acyclic monoolefins include ethylene, propylene, 1-butene, isobutylene, 1-pentene and 1-hexene. Examples of cyclic monoolefins include cyclopentene, cyclohexene, cycloheptene, cyclooctene and 4-methyl-cyclooctene. Examples of vinyl monomers include styrene, acrylonitrile, acrylic acid, ethylacrylate, vinyl chloride, butylacrylate, methyl vinyl ether, vinyl acetate and vinyl pyridine. Examples of vinylidene monomers include alpha-methylstyrene, methacrylic acid, methyl methacrylate, itaconic acid, ethyl methacrylate, glycidyl methacrylate and vinylidene chloride. Representative examples of synthetic polymers used in the practice of the present invention are polychloroprene homopolymers of conjugated 1,3-dienes, such as isoprene and butadiene, and in particular polyisoprene and poly, in which all repeat units are essentially linked in cis-1,4-structure. butadiene; Copolymers of conjugated 1,3-dienes such as isoprene and butadiene having at least 50% by weight of one or more copolymerizable monomers (eg, ethylenically unsaturated monomers such as styrene or acrylonitrile); And butyl rubber, which is a polymerization product of a large amount of monoolefin and a small amount of diolefin (for example, butadiene or isoprene). The rubber may be emulsion polymerized or solution polymerized. Preferred synthetic rubbers that can also be used in the present invention include cis-1,4-polyisoprene; Polybutadiene; Polychloroprene and copolymers of isoprene and butadiene; Copolymer of acrylonitrile and butadiene; Copolymers of acrylonitrile and isoprene; Copolymers of styrene, butadiene and isoprene; Copolymers of styrene and butadiene and blends thereof. The compounds of the present invention preferably have natural rubber present, but the natural rubber may be partially replaced with any synthetic rubber. Preferred rubbers that can be used in the present invention include natural rubbers; And cis-1,4-polyisoprene, polybutadiene, copolymers of isoprene and butadiene, copolymers of acrylonitrile and butadiene, copolymers of styrene and butadiene and isoprene, copolymers of styrene and butadiene, and blends thereof It may be a blend of synthetic rubber selected from the group.

According to one embodiment of the present invention, the rubber composition may include a filler, for example, silica or carbon black.

The silica may be any of those that are generally known, for example, commercially available Z-175, US7000GR or 9000GR.

When the content of the silica is less than 1 part by weight based on 100 parts by weight of the raw rubber, the effect of adding the silica is negligible, and when it exceeds 20 parts by weight, there may be a problem in terms of processability.

The silica may have a nitrogen adsorption specific surface area (nitrogen surface area per gram, N ₂ SA) of 100 to 180 m2 / g, and a CTAB (cetyl trimethyl ammonium bromide) adsorption specific surface area of 110 to 170 m2 / g. It is not limited to this.

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

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

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

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 an amount of 30 to 80 parts by weight based on 100 parts by weight of the raw material rubber, preferably 45 to 65 parts by weight, and more preferably 53 to 57 parts by weight. If the content of the carbon black is less than 30 parts by weight, the reinforcing performance by the carbon black as a filler may be deteriorated, and if it exceeds 80 parts by weight, the processability of the rubber composition may be disadvantageous.

The rubber composition for a tire sidewall may further include various additives such as additional vulcanizing agents, vulcanization accelerators, vulcanization accelerators, anti-aging agents, antioxidants, or softeners. Any of the various additives may be used as long as they are commonly used in the field to which the present invention pertains, and their content is not particularly limited as it is in accordance with the compounding ratio used in the conventional tire belt rubber composition.

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 vulcanizing agents such as tetraethyltriuram disulfide (TETD) and dithiodimorpholine can be used. Specifically, the sulfur vulcanizing agent may be elemental sulfur or a vulcanizing agent that produces sulfur, for example, amine disulfide, polymer sulfur, and the like.

The vulcanizing agent is preferably contained in 0.5 to 10.0 parts by weight based on 100 parts by weight of the raw rubber, and is preferable in that the raw rubber is less sensitive to heat and chemically stable.

The vulcanization accelerator means an accelerator that accelerates the vulcanization rate or accelerates the delaying action in the initial vulcanization step.

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

Examples of the sulfenamide-based vulcanization accelerator include N-cyclohexyl-2-benzothiazylsulfenamide (CBS), N-tert-butyl-2-benzothiazylsulfenamide (TBBS), and 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 The sulfenamide-based compound 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 Ethyl 4-morpholinothio) benzothiazole and any thiazole-based compound selected from the group consisting of these can be used.

Examples of the thiuram-based vulcanization accelerator include tetramethyl thiuram disulfide (TMTD), tetraethyl thiuram disulfide, tetramethyl thiuram monosulfide, dipentamethylene thiuram disulfide, dipentamethylene thiuram monosulfide, and dipentamethylene. Thiuram tetrasulfide, dipentamethylene thiuram hexasulfide, tetrabutyl thiuram disulfide, pentamethylene thiuram tetrasulfide, and any combination of these can be used.

The thiourea-based vulcanization accelerator may be any thiourea system selected from the group consisting of thiacarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea, diorthotolylthiourea, and combinations thereof. Compounds can be used.

As the guanidine-based vulcanization accelerator, any guanidine-based compound selected from the group consisting of diphenylguanidine, diorthotolylguanidine, triphenylguanidine, orthotolylbiguanide, diphenylguanidine phthalate, and combinations thereof may be used. You 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, zinc pentamethylenedithiocarbamate and piperidine, hexadecylisopropyldithiocarbamate, zinc octadecyl Zinc isopropyldithiocarbamate dibenzyldithiocarbamate zinc, diethyldithiocarbamate sodium, pentamethylenedithiocarbamate piperidine, dimethyldithiocarbamate selenium, diethyldithiocarbamate tellurium, dia Any dithiocarbamate-based compound selected from the group consisting of cadmium mildiocarbamate and combinations thereof can be used.

The aldehyde-amine or aldehyde-ammonia-based vulcanization accelerator may be, for example, an aldehyde selected from the group consisting of acetaldehyde-aniline reactant, butylaldehyde-aniline condensate, hexamethylenetetramine, acetaldehyde-ammonia reactant, and combinations thereof. -Amine-based or aldehyde-ammonia-based compounds can be used.

As the imidazoline-based vulcanization accelerator, for example, an imidazoline-based compound such as 2-mercaptoimidazoline can be used, and as the xanthate-based vulcanization accelerator, for example, xanthate-based zinc dibutylxanthogenate Compounds 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 material rubber in order to maximize productivity and promote rubber properties through acceleration of vulcanization.

The vulcanization accelerator may be used in combination with the vulcanization accelerator to complete its promoting 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. have. 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 can be used.

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

When the zinc oxide and the stearic acid are used together, they may be used in an amount of 1 to 10 parts by weight and 0.5 to 3 parts by weight relative to 100 parts by weight of the raw material rubber, respectively, in order to serve as an appropriate vulcanization accelerator. When the content of the zinc oxide and the stearic acid is less than the above range, the vulcanization rate may be slow and productivity may be lowered.

The softener is added to the rubber composition to impart plasticity to the rubber to facilitate processing or to lower the hardness of the vulcanized rubber, and means oils or other materials used in rubber compounding or rubber production. The softener means oils included in a process oil or other rubber composition. As the softener, any one selected from the group consisting of petroleum-based 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 paraffin oil, naphthenic oil, aromatic oil, and combinations thereof can be used.

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

However, when the content of the polycyclic aromatic hydrocarbons (Polycyclic Aromatic Hydrocarbons, hereinafter referred to as PAHs) contained in the aromatic oil with a heightened environmental awareness is more than 3% by weight, it is known to have high cancer-causing potential, TDAE ( Treated distillate aromatic extract (oil) oil, MES (mild extraction solvate) oil, RAE (residual aromatic extract) oil or heavy naphthenic oil can be preferably used.

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

The TDAE oil has excellent properties for environmental factors such as cancer inducibility of PAHs while improving the low-temperature characteristics and fuel efficiency of the tire including the TDAE oil.

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, sage flower oil, copper oil, and any one selected from the group consisting of combinations thereof.

The softener is preferably used in an amount of 0 to 10 parts by weight based on 100 parts by weight of the raw material rubber, in order to improve the processability of the raw material rubber.

The anti-aging agent is an additive used to stop the chain reaction in which the 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 can 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 can be used. The phenol-based anti-aging agent is phenol-based 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 can be used. As the quinoline-based anti-aging agent, 2,2,4-trimethyl-1,2-dihydroquinoline and derivatives thereof may be used, and 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, in addition to the anti-aging action, considering the conditions such as having a high solubility in rubber, small volatility, inertness to rubber, and not inhibiting vulcanization, 1 to 10 parts by weight based on 100 parts by weight of the raw rubber It may be included in parts by weight.

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

Referring to FIG. 1, the tire 10 includes a tread portion 100, a side wall portion 200, and a bead portion 300.

The tread portion 100 is a section in contact with the ground in cross-section, and serves to protect the tire from impact from the road surface, trauma, and the like. On the surface of the tread portion, a plurality of blocks partitioned by grooves may be formed for the drainage of the tire.

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

The sidewall 200 extends from both ends of the tread to form a side surface of the tire, and withstands the repeated contraction and expansion during driving, and protects the carcass layer 400 located on the inner surface. Do it.

A rubber composition according to an embodiment of the present invention is included in the sidewall. The internal pressure of the tire is significantly higher than atmospheric pressure, and as the driving time increases, the temperature becomes a high temperature exceeding 120 ° C. Therefore, due to the vertical movement of the vehicle in such a high temperature and high pressure state, repeated stretching and contraction movement occurs in the sidewall portion. Even in a stationary situation, the wax diffuses over time, and the diffusion of the wax in this situation can be further promoted.

The rubber composition for tire sidewalls according to an embodiment of the present invention has wax A having a maximum carbon molecular weight distribution of 31 to 38 (for example, a maximum carbon molecular weight distribution of wax A is 33 to 35) and a maximum carbon molecular weight distribution of 25 to 30, including wax B (the maximum carbon molecular weight distribution of wax B is 27 to 29), in the case of wax A, the proportion of normal paraffin is 50 to 70%, and the proportion of iso paraffin is 30 to 50% (for example, , Wax A has a normal paraffin ratio of 55 to 65%, isoparaffin has a ratio of 34 to 45%, and wax B has a normal paraffin ratio of 70 to 85% (for example, wax B has a normal ratio). The ratio of paraffin is 73 to 83%). In the wax content, the ratio of the weight part of the wax A to the weight part of the wax B is preferably 0.59 to 5.7. When the content of wax A is applied equal to or more than the content of wax B, the glossiness can be increased. For example, a ratio of parts by weight of the wax A to parts by weight of the wax B may be 1 to 3. Specifically, the content of the wax A may be 1.0 to 1.7 parts by weight, and the content of the wax B may be 0.3 to 1.7 parts by weight.

When the maximum carbon molecular weight distribution of each of wax A and wax B, the ratio of normal paraffin, and the ratio and content of isoparaffin are within the above ranges, blooming suppression and glossiness are optimal.

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 steel wire in the form of a ring.

The carcass layer 400 is positioned between the left and right pair of bead parts 300 and is bonded to the tire rubber sheet inside the tire to form a skeleton of the tire, and the carcass layer 400 is a bead core 500 ) It is wound up from the inside of the tire to the outside.

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

On the outer surface of the carcass layer 400 positioned on the tread portion 100, the belt layer 600 may be positioned as a reinforcing layer that increases the elasticity of the tread and has controllability and stability.

The rubber composition for the tire sidewall can be prepared by controlling temperature and pressure conditions. That is, it can be prepared under pressure and temperature conditions at a maximum temperature of 150 to 190 ° C, preferably 160 to 180 ° C, but is not limited thereto.

The tire according to another embodiment of the present invention includes the step of using the rubber composition for sidewalls when forming a green tire. The method of forming a green tire using the rubber composition for a tire sidewall can be applied to any method that is conventionally used for the production of tires, and detailed description is omitted herein.

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 may maintain the tire performance by suppressing the flow of the belt layer 600 when driving.

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

The present invention is described in more detail through the following examples and comparative examples. However, the examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

Example  1 to 2 and Comparative example  1 to 2

The composition shown in Table 1 was added to the Banbari mixer to mix the rubber compositions of Examples and Comparative Examples.

Comparative Example 1 Comparative Example 2 Example 1 Example 2 combination
(Parts by weight) Natural rubber 50 50 50 50 BR 50 50 50 50 Carbon black ^{1 )} 50 50 50 50 ZnO 3.0 3.0 3.0 3.0 Stearic acid 1.5 1.5 1.5 1.5 Wax Universal ^{2 )} 2.0 - - - Wax A / Wax B - 0.5 / 1.5 1.0 / 1.0 1.5 / 0.5 6PPD ^{3 )} 3.0 3.0 3.0 3.0 TMQ ^{4 )} 1.0 1.0 1.0 1.0 Oil ^{5 )} 7.0 7.0 7.0 7.0 N-SUL ^{6 )} 1.8 1.8 1.8 1.8 TBBS ^{7 )} 0.75 0.75 0.75 0.75

1) Carbon black: N330

2) SUNOC # 315 (C30 ~ C33)

3) N- (1,3-DIMETHYLBUTYL) -N-PHENYL-P-PHENYLENDIAMINE

4) 2,2,4-TRIMETHYL-1,2-DIHYDROQUINOLINE, POLYMERIZED

5) RAE Oil

6) Sulfur

7) N-TERTIARYBUTYL-2-BENZOTHIAZOLE-SULFENAMIDE

The rubber sheet prepared above was fabricated in a vulcanizer at 160 ° C. for 10 minutes to prepare a vulcanized specimen.

Evaluation example

The basic properties of the specimens prepared in Examples 1 to 2 and Comparative Examples 1 to 2 were evaluated as follows, and the results are shown in Table 2 below.

HD (hardness)

6mm or more thickness and 10mm diameter according to ASTM D2240-97 using Shore A hardness tester

From the above smooth surface, one specimen was measured five times in total, and the average value was determined.

Tensile properties

Measurement of the tensile strength of the crosslinked specimen was performed according to ASTM D412 using a tensile tester (INSTRON). The specimen for measurement was manufactured in the form of a sheet using a hydraulic press, and in the form of a dumbbell using a specimen cutter. As a test condition, the tensile speed at room temperature was measured at 500 mm / min.

M-300 is a value indicating the stress value at 300% elongation in a tensile tester, and the force received per unit area was measured.

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 was measured.

E / B represents the elongation at break of the test piece in the tensile tester.

Comparative example  One Comparative example  2 Example  One Example  2 HD [Hardness] 54 54 54 54 M-300 (kgf / cm ² ) 62 60 61 66 T / S (kgf / cm ² ) 215 220 210 208 E / B (%) 670 670 650 690

From the results of Table 2, it can be seen that the basic properties of rubber vulcanized with the rubber compositions of Comparative Examples 1 and 2 and Examples 1 and 2 are not significantly different.

With respect to the specimens prepared in Examples 1 to 2 and Comparative Examples 1 to 2 (7 days elapsed), glossiness was measured at an incident angle of 60 ° by micro-tri-gloss (BYK), and the results are shown in Table 3 below. .

Comparative example  One Comparative example  2 Example  One Example  2 Glossiness
(Incident angle 60 °) 11.6 16.8 32.0 35.7

As can be seen from Table 3, in Comparative Example 1 using a general-purpose wax, the gloss was low. In the case of Comparative Example 2 in which the content of wax A was less than 1.0, the glossiness was similarly low. In the case of Examples 1 and 2 in which the content of the wax A and the content of the wax B were 1.0 / 1.0 and 1.5 / 0.5, respectively, high gloss was shown.

The surface photographs of the specimens are shown in FIG. 2.

Referring to FIG. 2, it can be seen that the surfaces of the specimens match the gloss values in Table 3.

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

Claims (10)

Raw rubber including natural rubber and synthetic rubber derived from diene monomer; And
Wax A having a maximum carbon molecular weight distribution of 31 to 38 and Wax B having a maximum carbon molecular weight distribution of 25 to 30,
The proportion of the normal paraffin of the wax A is 50 to 70%, the proportion of the iso paraffin is 30 to 50%,
The ratio of the normal paraffin of the wax B is 70 to 85%,
The ratio of parts by weight of the wax A to parts by weight of the wax B is 1 to 3
Rubber composition for tire sidewalls. delete delete delete The rubber composition for a tire sidewall according to claim 1, wherein the content of the wax A is 1.0 to 1.7 parts by weight. The rubber composition for a tire sidewall according to claim 1, wherein the content of the wax B is 0.3 to 1.7 parts by weight. delete The rubber composition for a tire sidewall according to claim 1, wherein the synthetic rubber comprises butadiene rubber. A tire comprising a sidewall obtained by vulcanizing the rubber composition for a sidewall according to any one of claims 1, 5, 6, and 8. The tire of claim 9, wherein the sidewall of the tire has a glossiness value measured at 60 ° (incident angle) with a BYK (Micro-TRI-gloss) gloss meter.

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