KR101778777B1 - Reinforcement composition for sidewall of run-flat tire - Google Patents

Abstract

According to an embodiment of the present invention, provided is a rubber reinforcing material composition for a run flat tire sidewall, wherein the rubber reinforcing material composition comprises: 90 to 99 wt% of a heterogeneous polybutadiene mixture; and 1 to 10 wt% of an additive consisting of aramid pulp or phenolic resin. The rubber reinforcing material composition for a run flat tire side wall of the present invention can be provided with excellent tensile properties and fuel efficiency.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a rubber reinforcing material composition for a run flat tire,

The present invention relates to a rubber reinforcement composition for run flat tire side walls.

Run-flat tires are made by adding a high-elasticity, high-strength special rubber to the sidewall that is the basic skeleton, to improve the strength of the tires. It says.

Such a run flat tire does not require dangerous and complicated tire replacement work on the road and does not require extra tire inside the vehicle, so that it is possible to lighten the vehicle body, thereby improving fuel efficiency. Is increasing.

In order to improve the strength of a conventional run flat tire, a method of preventing tire breakage by suppressing deformation of the tire by increasing the thickness of the reinforcing layer of the tire side wall has been proposed. However, there is a problem that the weight of the tire is increased to decrease the fuel efficiency.

On the other hand, a rubber composition capable of improving the strength and lightness of the rubber by applying crystalline syndiotactic-1,2-polybutadiene has been proposed. However, when the content is below a certain level, the rubber composition is insufficient, There is a lowering limit.

On the other hand, it is advantageous to use silica rather than carbon black in blending rubber for run flat tire side wall from the viewpoint of fuel efficiency improvement. However, when the conventional gossy-1,4-polybutadiene rubber is used, the polymer chain has no polar functional group Therefore, the silica dispersibility is insufficient and the durability is low.

Accordingly, development of a rubber reinforcing material composition for a run flat tire side wall which is excellent in durability, especially initial tensile characteristics and fuel efficiency, is required.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a rubber reinforcing material composition for run flat tire side wall having excellent tensile properties and fuel efficiency.

One aspect of the present invention relates to a composition comprising 90 to 99% by weight of a heterogeneous polybutadiene mixture; And 1 to 10% by weight of an aramid pulp, a phenolic resin, or a mixture thereof.

In one embodiment, the heterogeneous polybutadiene mixture may be prepared by mixing 1,4-polybutadiene and 1,2-polybutadiene in a weight ratio of 60:90 to 40:10, respectively.

In one embodiment, the 1,4-polybutadiene may be gossy-1,4-polybutadiene.

In one embodiment, the gossy-1,4-polybutadiene may be a terminally modified gossy-1,4-polybutadiene.

In one embodiment, the end-modified gossy-1,4-polybutadiene can be end-modified by a modifier of the formula (1).

[Chemical Formula 1]

Wherein R ₁ to R ₃ are each an alkyl group or an alkoxy group of C ₁ to C 5, R ₄ is a C 1 to C 5 alkyl group containing an isocyanate group, an epoxy group or a carboxyl group, and n is an integer of 1 to 5 .

In one embodiment, the 1,2-polybutadiene may be syndiotactic-1,2-polybutadiene.

In one embodiment, 80 to 120 parts by weight of an isoprene rubber, 60 to 140 parts by weight of silica, and 5 to 15 parts by weight of a silane coupling agent may be further added to 100 parts by weight of the rubber reinforcement composition for run flat tire side wall have.

In one embodiment, the isoprene rubber is selected from the group consisting of natural rubber (NR), isoprene rubber (IR), liquid isoprene rubber (L-IR), epoxidized natural rubber (ENR) Can be selected.

In one embodiment, the rubber reinforcement composition for run flat tire sidewall may further comprise at least one additive selected from the group consisting of sulfur, a vulcanization accelerator, and a process oil.

Further, another aspect of the present invention provides a run flat tire including a sidewall to which a rubber reinforcement composition for run flat tire sidewalls is applied.

According to one aspect of the present invention, aramid pulp or a phenolic resin may be added to improve the tensile properties, particularly the initial tensile properties, of the rubber reinforcing material composition for run flat tire side walls.

Further, the dispersibility of silica in the rubber reinforcing material composition can be improved by using a certain amount of end-modified gossy-1,4-polybutadiene, thereby improving the tensile characteristics and fuel efficiency of the rubber reinforcing material composition .

It should be understood that the effects of the present invention are not limited to the effects described above, but include all effects that can be deduced from the description of the invention or the composition of the invention set forth in the claims.

Hereinafter, the present invention will be described. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

One aspect of the present invention relates to a composition comprising 90 to 99% by weight of a heterogeneous polybutadiene mixture; And 1 to 10% by weight of an aramid pulp, a phenolic resin, or a mixture thereof.

The heterogeneous polybutadiene mixture may be a mixture of 1,4-polybutadiene and 1,2-polybutadiene, and specifically, they may be mixed at a weight ratio of 60 to 90:40 to 10, respectively. These are used in combination with each other as compared with the case where they are used singly, so that the tire strength can be secured at a level suitable for the run flat function, and the amount of sulfur used can be reduced to improve workability and dispersibility.

The 1,4-polybutadiene is a high cis-1,4-butadiene containing 90 wt% or more, preferably 95 wt% or more, and more preferably 97 wt% or more of cis- Polybutadiene. The higher the sheath content of the 1,4-polybutadiene, the more improved the heat resistance and elasticity of the rubber.

Since the gossy-1,4-polybutadiene has no polar functional group in the molecule, the dispersibility of the gossy-1,4-polybutadiene may be deteriorated when mixed with silica to be described later. Therefore, the gossy- , I.e., an end-modified gossy-1,4-polybutadiene.

The terminal-modified gossy-1,4-polybutadiene may have a polar functional group such as an isocyanate group, an epoxy group and a carboxyl group introduced into the molecule to improve compatibility with the silica. Thus, silica may be uniformly dispersed in the rubber The tensile properties and fuel efficiency of the rubber reinforcing material composition can be improved.

Accordingly, the end-modified gossy-1,4-polybutadiene may be end-modified with a modifier of the following formula (1).

[Chemical Formula 1]

Wherein R ₁ to R ₃ are each an alkyl group or an alkoxy group of C ₁ to C 5, R ₄ is a C 1 to C 5 alkyl group containing an isocyanate group, an epoxy group or a carboxyl group, and n is an integer of 1 to 5 .

According to the above formula 1, the modifier may include, for example, 2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethyltriethoxysilane, (2-glycidoxyethyl) methyldimethoxysilane, 3- 3-glycidoxypropyltriethoxysilane, (3-glycidoxypropyl) methyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2 - (3,4-epoxycyclohexyl) ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl (methyl) dimethoxysilane, 3-isocyanatepropyltrimethoxysilyl, 3-isocyanatepropyltriethoxy Silane, 3-isocyanate propyl methyldiethoxy silane, 3-isocyanate propyl triisopropoxy silane, 3-methacryloyl oxypropyl trimethoxy silane, 3-methacryloyloxypropyl triethoxy silane, 3- Acryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropyltri 3-isocyanatopropyltriethoxysilane, 3-isocyanate propyltriethoxysilane, 3-isocyanate propyltrimethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltrimethoxysilane, Methyldiethoxysilane, 3-isocyanatepropyltriisopropoxysilane, and more preferably 3-isocyanatepropyltrimethoxysilane, but is not limited thereto.

On the other hand, the 1,2-polybutadiene may be syndiotactic-1,2-polybutadiene, which is a crystalline polymer. Accordingly, the rubber reinforcing material composition may be in the form of dispersing 1,2-polybutadiene, specifically crystalline syndiotactic-1,2-polybutadiene, in the amorphous 1,4-polybutadiene matrix.

The syndiotactic 1,2-polybutadiene can maintain its strength at a certain level or higher between the rubber reinforcing material composition and the run flat tire.

The syndiotactic 1,2-polybutadiene may have a syndiotactic 1,2-arrangement in the total 1,2-polybutadiene arrangement having about 30% or more monomer units, preferably about 40% or more monomer Unit.

The melting point of the syndiotactic-1,2-polybutadiene may be 110 to 220 ° C, preferably 110 to 150 ° C. If the melting point is less than 110 ° C, the rotational resistance of the rubber reinforcing material composition increases, so that the fuel efficiency and the tensile strength at high temperatures of the tire may be lowered. If the melting point is higher than 220 ° C, the workability may be lowered.

If the content of 1,2-polybutadiene, that is, syndiotactic-1,2-polybutadiene is less than 10% by weight based on the total weight of the heterogeneous polybutadiene mixture, the strength of the rubber reinforcing material composition may be lowered, If the amount is more than 40% by weight, the workability may be deteriorated. Therefore, the content of the 1,2-polybutadiene may be 10 to 40% by weight.

If the content of the heterogeneous polybutadiene mixture is less than 90% by weight based on the total weight of the rubber reinforcement composition for run flat tire, the workability may be deteriorated. If the content is more than 99% by weight, The content of the heterogeneous polybutadiene mixture may be preferably 90 to 99% by weight.

The aramid pulp and / or phenolic resin can improve the strength reinforcing effect of the rubber reinforcing material composition, specifically, the tensile properties. At this time, the content of the aramid pulp and / or the phenolic resin may be 1 to 10% by weight based on the total weight of the rubber reinforcing material composition.

If the content of the aramid pulp and / or the phenolic resin is less than 1% by weight, the strength reinforcing effect may be insufficient. If the aramid pulp and / or phenolic resin is more than 10% by weight, the relative content of the heteropolybutadiene mixture may be decreased, have.

The aramid pulp may be an aggregate of aramid fibers prepared by mechanically and chemically processing aramid fibers. As used herein, the term " aramid fiber " refers to an aromatic polyamide fiber prepared by introducing an amide group into an aromatic compound such as benzene. The aramid fiber has excellent tensile strength, heat resistance, .

When the aramid pulp is added to the rubber reinforcing material composition, the individual aramid fibers can be dispersed in the rubber matrix, thereby improving the tensile properties, specifically, the initial tensile properties of the rubber reinforcing material composition.

When the aramid fiber is applied to a rubber reinforcing material composition, the structural and chemical properties such as the diameter, length and surface treatment of the fiber are usually modified and modified in consideration of compatibility with rubber and dispersibility. However, the aramid pulp is obtained by mechanically and chemically processing the aramid fiber. The aramid pulp has less burden on the deformation and modification of the fiber than the aramid fiber, and improves the compatibility with the rubber and improves the dispersibility. .

On the other hand, since the phenolic resin is excellent in tackiness, a strong adhesive force can be imparted between the components contained in the rubber reinforcing composition, and thus the hardness, strength, and heat resistance of the rubber reinforcing composition can be improved.

Examples of the phenol resin include a phenol resin, a cresol resin, a bisphenol A resin, or a phenol-formaldehyde resin in which phenol and formaldehyde are condensed. Preferably, the phenol resin is a cresol resin, no.

In addition, a phenol resin such as hexamethoxymethylmelamine (HMMM) or hexamethylenetetramine (HMT) may be mixed with a cresol resin in order to improve the bonding strength between resins, but the present invention is not limited thereto.

Further, it may further comprise 80 to 120 parts by weight of an isoprene rubber, 60 to 140 parts by weight of silica, and 5 to 15 parts by weight of a silane coupling agent based on 100 parts by weight of the rubber reinforcement composition for run flat tire side wall.

The isoprene rubber may be one selected from the group consisting of natural rubber (NR), isoprene rubber (IR), liquid isoprene rubber (L-IR), epoxidized natural rubber (ENR) , Preferably natural rubber having excellent extensibility and processability, but is not limited thereto.

When the content of the isoprene rubber is less than 80 parts by weight based on 100 parts by weight of the rubber reinforcing material composition, the elongation percentage of the rubber reinforcing material composition may be lowered. When the amount of the isoprene rubber is more than 120 parts by weight, And / or the relative content of the phenolic resin may be reduced and the tensile properties and fuel efficiency may be lowered.

In conventional rubber processing, silica or carbon black is used alone or as a reinforcing agent for improving tensile properties. However, it is preferable to use silica as compared with the case of using carbon black as the reinforcing agent in terms of improvement in fuel efficiency. In addition, the silica can be uniformly dispersed in the rubber reinforcing material composition by the polar functional group present in the end-modified gossy-1,4-polybutadiene as described above.

The content of the silica may be 60 to 140 parts by weight based on 100 parts by weight of the rubber reinforcing material composition. If the amount of the silica is less than 60 parts by weight, the effect of improving the tensile properties may be insufficient. If the amount is more than 140 parts by weight, the workability of the rubber reinforcing material composition may be deteriorated.

In addition, the rubber reinforcing material composition may further include a silane coupling agent so as to improve dispersibility of the silica together with the end-modified gossy-1,4-polybutadiene.

If the content of the silane coupling agent is less than 5 parts by weight based on 100 parts by weight of the rubber reinforcing material composition, the effect of improving the silica dispersibility is weak. If the content of the silane coupling agent is more than 15 parts by weight, The processability of the substrate may be deteriorated.

Specifically, the silane coupling agent may be at least one selected from the group consisting of a sulfide-based silane compound, a mercapto-based silane compound, a vinyl-based silane compound, an amino-based silane compound, a glycidoxime silane compound, And mixtures of two or more thereof, preferably bis (3-triethoxysilylpropyl) tetrasulfide (TESPT), but is not limited thereto.

On the other hand, the above-mentioned rubber reinforcing material composition may further comprise, in addition to the above-mentioned components, a compounding agent or an additive used in conventional rubber processing, for example, sulfur, vulcanization accelerators and process oil.

The sulfur may be any material capable of promoting the crosslinking reaction between the rubber reinforcing material compositions by having vulcanizing properties regardless of the kind thereof such as powdered sulfur, insoluble sulfur, precipitated sulfur, and colloidal sulfur.

The vulcanization accelerator may be at least one selected from the group consisting of aldehyde amine, guanidine, thiazole, sulfenamide, dithiocarbamate, thiuram, thiourea, (Thiourea), and mixtures of two or more thereof. Specifically, N-tert-butyl-2-benzothiazole-sulfenamide (TBBS), 2-mercaptobenzothiazole ), Tetramethylthiuram disulfide (TMTD), diphenyl guanidine (DPG), N-cyclohexyl-2-benzothiazole-sulfenamide (CBS), and the like.

As the vulcanization accelerating assistant for improving the promoting effect of the vulcanization accelerator, an inorganic vulcanization accelerator aid, an organic vulcanization aid aid, or a combination thereof may be used. As the inorganic vulcanization accelerating auxiliary, zinc oxide, zinc carbonate, magnesium oxide, lead oxide, potassium hydroxide and the like can be used. As the organic vulcanization accelerator auxiliary, there can be used stearic acid, zinc stearate, palmitic acid, Lauric acid and the like can be used.

Particularly, the crosslinking reaction of the rubber reinforcing material composition can be facilitated by using the inorganic vulcanization accelerating auxiliary and the organic vulcanizing accelerating auxiliary, specifically zinc oxide and stearic acid together to free sulfur in the vulcanizing step.

When the crosslinking reaction proceeds between the rubber reinforcing material compositions during the vulcanization process, the rubber reinforcing material composition hardens due to the rigid crosslinking. At this time, the process oil can be improved in workability by imparting plasticity to the rubber reinforcing material composition.

The process oil may be a petroleum oil or a vegetable oil. Examples of the petroleum oil include paraffin oil, naphthene oil, and aromatic oil, but the present invention is not limited thereto.

Specifically, the process oil preferably has a content of polycyclic aromatic hydrocarbons (PAHs) of 3 wt% or less, a kinematic viscosity of 95 캜 or higher (210 S SUS), an aromatic component of 15 to 25 (Treated Distillate Aromatic Extract) oil having a naphthene content of 27 to 37% by weight, and a paraffinic content of 38 to 55% by weight. The TADE oil has an eco-friendly property by minimizing the content of PAHs, which is a carcinogen, while improving the heat generation characteristics and fuel efficiency of the run flat tire sidewall.

The rubber reinforcing material composition may be selected from the group consisting of a flame retardant, an impact modifier, a flame retardant aid, a lubricant, a plasticizer, a heat stabilizer, a dripping inhibitor, an antioxidant, a compatibilizer, a light stabilizer, a pigment, a dye, an inorganic additive, And may further comprise one or more additives selected.

The content of the additive may be 0.1 to 10% by weight based on the total weight of the rubber reinforcing material composition. If the content of the additive is less than 0.1 wt%, an effect suitable for the intended use can not be achieved. If the additive is more than 10 wt%, the physical properties of the rubber reinforcing material composition may be deteriorated.

Further, another aspect of the present invention provides a run flat tire including a sidewall to which a rubber reinforcement composition for run flat tire sidewalls is applied.

A method for producing a run flat tire sidewall using the rubber reinforcement composition for a run flat tire side wall and a method for manufacturing a run flat tire by connecting the sidewall and the tread are not limited as long as they are used in the production of conventional tires Can be applied.

The run flat tire can be used for passenger cars, racing, airplanes, agricultural machinery, off-the-road, trucks, buses and the like. Especially, according to recent light- It can be used for racing.

Hereinafter, embodiments of the present invention will be described in more detail.

Manufacturing example  One

66 wt% of gossy-1,4-polybutadiene modified at its terminals by adding 3-isocyanate-propyltrimethoxysilane to gossy-1,4-polybutadiene prepared using Nd catalyst, syndiotactic 1,2 30% by weight of polybutadiene and 4% by weight of aramid pulp were blended at 130 DEG C with 500 cc Brabender to prepare a rubber reinforcing material composition for run flat tire side wall.

Manufacturing example  2

A rubber reinforcing material composition for a run flat tire side wall was prepared in the same manner as in Preparation Example 1, except that the aramid pulp was replaced with a cresol resin.

Manufacturing example  3

A rubber reinforcing material composition for a run flat tire side wall was prepared in the same manner as in Preparation Example 1, except that gossy-1,4-polybutadiene having no terminal modified was used.

Manufacturing example  4

A rubber reinforcing material composition for a run flat tire side wall was prepared in the same manner as in Preparation Example 2, except that the gossy-1,4-polybutadiene having no terminal modified was used.

Manufacturing example  5

A rubber reinforcing material composition for a run flat tire side wall was prepared in the same manner as in Example 1, except that 70% by weight of gossy-1,4-polybutadiene having no end modified, except for aramid pulp, was used.

Manufacturing example  6

66 wt% of gossy-1,4-polybutadiene modified at its terminals by adding 3-isocyanate-propyltrimethoxysilane to gossy-1,4-polybutadiene prepared using Nd catalyst, syndiotactic 1,2 30% by weight of polybutadiene, 3% by weight of aramid pulp, and 1% by weight of cresol resin were blended at 500 占 폚 with a brabender at 130 占 폚 to prepare a rubber reinforcing material composition for run flat tire side wall.

The specific composition of each of the rubber stiffener compositions for run flat tire sidewall prepared according to the above Production Examples is shown in Table 1 below.

Furtherance Production Example 1 Production Example 2 Production Example 3 Production Example 4 Production Example 5 Production Example 6 Gossy-1,4-polybutadiene - - 66 66 70 - End-modified gossy-1,4-polybutadiene 66 66 - - - 66 Syndiotactic-1,2-polybutadiene 30 30 30 30 30 30 Aramid pulp 4 - 4 - - 3 Cresol resin - 4 - 4 - One

(Unit: wt%)

Example  And Comparative Example

(TESPT), bis- (3-triethoxysilylpropyl) tetrasulfide, and process oil (TDAE) were prepared in the same manner as in Example 1, except that each rubber composition for run flat tire sidewall prepared according to the above Preparation Example was mixed with natural rubber, zinc oxide, stearic acid, silica, silane coupling agent , Treated Distillate Aromatic Extract) were blended in a 500 cc Brabender at 120 占 폚. Then, sulfur and a vulcanization accelerator were mixed and stirred to obtain rubber compositions for run flat tire side walls of Examples 1 to 3 and Comparative Examples 6 and 7, , An insert rubber composition for a run flat tire side wall was produced. In Comparative Examples 1 to 5, carbon black was used instead of silica and a silane coupling agent.

The specific compositions of the insert rubber compositions for run flat tire sidewalls according to Examples 1 to 3 and Comparative Examples 1 to 7 are shown in Table 2 below.

Furtherance Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Natural rubber 50 50 50 50 50 50 50 50 50 50 Production Example 1 50 - - 50 - - - - - - Production Example 2 - 50 - - 50 - - - - - Production Example 3 - - - - - 50 - - 50 Production Example 4 - - - - - - 50 - - 50 Production Example 5 - - - - - - - 50 - - Production Example 6 50 Zinc oxide 5 5 5 5 5 5 5 5 5 5 Stearic acid 3 3 3 3 3 3 3 3 3 3 Silica 50 50 50 - - - - - 50 50 Silane coupling agent 4 4 4 - - - - - 4 4 Carbon black - - - 45 45 45 45 45 - - Process oil 6 6 6 6 6 6 6 6 6 6 sulfur 5 5 5 5 5 2 2 2 5 5 Vulcanization accelerator One One One One One One One One One One

(Unit: parts by weight)

Experimental Example

The insert rubber compositions for run flat tire sidewalls according to Examples 1 to 3 and Comparative Examples 1 to 7 were each kneaded at 80 캜 by a roll mill and processed into a sheet form by a roll having a thickness of 2 mm And allowed to stand for 24 hours. Thereafter, vulcanization was carried out at a crosslinking time measured by a rubber process analyzer (RPA) at 160 캜 using a press to prepare a 2 mm thick sheet specimen.

The properties of the respective sheet specimens were measured according to the following methods, and the results are shown in Table 3 below.

- Mooney viscosity: measured at 100 캜 using MV 2000 (Alpha Technologies).

- Hardness: measured by the ASTM shore-A method.

Modulus, tensile strength, and elongation: measured according to ASTM D 790, and (tensile strength * elongation) / 2 was calculated as the breaking energy value.

The complex elastic modulus and Tan δ: Dynamic Mechanical Thermal Analyzer (DMTA) were used to measure the temperature at 60 ° C by a temperature sweep.

Heat build-up: Measured according to ASTM D623 using a flexometer (BF Goodrich).

Properties Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Mooney viscosity
(ML _{1 + 4} @ 100 ° C) 85.7 86.6 86.1 85.5 86.2 85.2 85.9 81.3 85.8 86.0 Hardness
(shorea) 75 76 75 74 75 73 74 71 74 74 10% Modulus (kgf / ㎡ @ 25 ℃) 13.8 14.1 14.2 12.8 12.9 12.5 12.6 9.2 12.5 12.6 Fracture energy
(MPa 占% @ 150 占 폚) 347 342 345 325 318 321 315 258 325 322 Complex modulus
(@ 60 ° C) 6.68 6.68 6.67 6.25 6.21 6.12 6.08 5.92 6.56 6.51 Tanδ
(@ 60 ° C) 0.039 0.041 0.038 0.049 0.050 0.048 0.049 0.041 0.043 0.044 Heat characteristic
(At 55 ° C) 61.5 61.2 61.6 64.3 64.5 65.1 65.0 62.8 63.6 63.8

First, with reference to Table 3, the properties of the specimens according to the presence or absence of the aramid pulp or the phenolic resin in the rubber reinforcing material composition using the gossy-1,4-polybutadiene having no terminal modification were compared with those of the aramid pulp or phenol- The tensile modulus of the specimen containing the resin (Comparative Examples 3 and 4) was 10% higher than that of the specimen without the resin (Comparative Example 5), so that the initial tensile properties are expected to be relatively good.

Comparing the physical properties of the specimens according to the type of the reinforcing agent, the specimens including silica (Examples 1 and 2) had a modulus of 10% and tan δ smaller than those of carbon black (Comparative Examples 1 and 2) It can be seen that excellent initial tensile characteristics and fuel efficiency can be realized.

In addition, comparing the properties of the specimens according to whether or not the gossy-1,4-polybutadiene was terminally modified, the specimens including the end-modified gossypse-1,4-polybutadiene (Examples 1 and 2) 10-fold modulus and tan δ were smaller than those of the specimens containing the polybutadiene-1,4-polybutadiene (Comparative Examples 6 and 7), indicating excellent initial tensile properties and fuel efficiency. In particular, this is analyzed as a result of improving the compatibility with silica by introducing a polar functional group at the terminal of the gossy-1,4-polybutadiene.

Comparing the physical properties of the specimens (Examples 1 and 2) which were alternatively applied with aramid pulp or cresol resin and the specimen (Example 3) in which they were applied in combination, it was found that 10% The modulus is large and the tan δ is small. Thus, it was confirmed that the simultaneous application of aramid pulp and cresol resin can achieve a synergistic effect that can further improve initial tensile characteristics and fuel efficiency.

From these results, it can be seen that the rubber composition for run flat tire sidewall can realize excellent initial tensile properties including aramid pulp and / or phenolic resin, and at the same time, - By using polybutadiene to improve compatibility with silica, excellent initial tensile properties and fuel efficiency can be realized.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims (10)

90 to 99% by weight of a heterogeneous polybutadiene mixture; And
1 to 10% by weight of a mixture comprising aramid pulp and a phenolic resin. The method according to claim 1,
Wherein the heterogeneous polybutadiene mixture is a mixture of 1,4-polybutadiene and 1,2-polybutadiene in a weight ratio of 60 to 90: 40 to 10, respectively. 3. The method of claim 2,
Wherein the 1,4-polybutadiene is gossy-1,4-polybutadiene, and the rubber reinforcing material composition for run flat tire side wall is 1,4-polybutadiene. The method of claim 3,
Wherein the gossy-1,4-polybutadiene is a terminal-modified gossy-1,4-polybutadiene. 5. The method of claim 4,
Wherein the end-modified gossy-1,4-polybutadiene is end-modified with a modifier of the following formula (1): < EMI ID =
[Chemical Formula 1]

Wherein R ₁ to R ₃ are each an alkyl group or an alkoxy group of C ₁ to C 5, R ₄ is a C 1 to C 5 alkyl group containing an isocyanate group, an epoxy group or a carboxyl group, and n is an integer of 1 to 5 . 3. The method of claim 2,
Wherein the 1,2-polybutadiene is syndiotactic-1,2-polybutadiene. The method according to claim 1,
Characterized in that it further comprises 80 to 120 parts by weight of an isoprene rubber, 60 to 140 parts by weight of silica, and 5 to 15 parts by weight of a silane coupling agent based on 100 parts by weight of the rubber reinforcement composition for run flat tire side wall. A rubber reinforcing material composition for a tire side wall. 8. The method of claim 7,
Wherein the isoprene rubber is one selected from the group consisting of natural rubber (NR), isoprene rubber (IR), liquid isoprene rubber (L-IR), epoxidized natural rubber (ENR) By weight based on the total weight of the rubber composition. 8. The method of claim 7,
The rubber reinforcement composition for a run flat tire side wall further comprises at least one additive selected from the group consisting of sulfur, a vulcanization accelerator, and a process oil. A run flat tire comprising a sidewall to which a rubber stiffener composition for a run flat tire sidewall according to any one of claims 1 to 9 is applied.