US20070112121A1 - Rubber composition and pneumatic tire using the same for tread - Google Patents
Rubber composition and pneumatic tire using the same for tread Download PDFInfo
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- US20070112121A1 US20070112121A1 US11/541,643 US54164306A US2007112121A1 US 20070112121 A1 US20070112121 A1 US 20070112121A1 US 54164306 A US54164306 A US 54164306A US 2007112121 A1 US2007112121 A1 US 2007112121A1
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- Prior art keywords
- silica
- grip performance
- rubber
- rubber composition
- weight
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
- B60C1/0016—Compositions of the tread
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/34—Silicon-containing compounds
- C08K3/36—Silica
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/54—Silicon-containing compounds
- C08K5/548—Silicon-containing compounds containing sulfur
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K2201/00—Specific properties of additives
- C08K2201/016—Additives defined by their aspect ratio
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/80—Technologies aiming to reduce greenhouse gasses emissions common to all road transportation technologies
- Y02T10/86—Optimisation of rolling resistance, e.g. weight reduction
Definitions
- the present invention relates to a rubber composition and a pneumatic tire.
- silica has been employed together with various coupling agents, a dispersing agent, a surface modifier and the like.
- a silane coupling agent is considered to prevent silica particles from coagulating each other due to bonding with silanol groups on the surface of silica and to improve processability of the rubber composition.
- no rubber composition in which dry grip performance can be improved besides rolling resistance is lowered has been put into practical use yet.
- JP-A-8-337687 discloses a rubber composition lowering rolling resistance by compounding particulate silica and a silane coupling agent, however, the rubber composition is insufficient in the improvement effects of wet grip performance and dry grip performance, and thus, it still has a scope to be improved.
- An object of the present invention is to provide a rubber composition in which both wet grip performance and dry grip performance are improved, while rolling resistance is maintained, and a pneumatic tire using the same.
- the present invention relates to a rubber composition
- a rubber composition comprising 5 to 150 parts by weight of silica having an aspect ratio of 2 to 20 based on 100 parts by weight of a rubber component containing a diene rubber.
- the present invention also relates to a pneumatic tire, wherein the rubber composition is used for a tread.
- the rubber composition of the present invention comprises a rubber component and silica.
- the rubber component contains a diene rubber since it can improve wet grip performance and abrasion resistance.
- a diene rubber examples are rubbers generally used in the rubber industry such as a natural rubber (NR), a styrene butadiene rubber (SBR), a butadiene rubber (BR), an isoprene rubber (IR), a butyl rubber (IIR), an acrylonitrile butadiene rubber (NBR), an ethylene propylene diene rubber (EPDM) and a chloroprene rubber (CR), these are not particularly limited, and they may be used alone or in combination of at least two kinds.
- NR natural rubber
- SBR styrene butadiene rubber
- BR butadiene rubber
- IR isoprene rubber
- IR butyl rubber
- NBR acrylonitrile butadiene rubber
- EPDM ethylene propylene diene rubber
- CR chloroprene rubber
- a combined styrene amount of SBR is preferably at least 20% by weight, and more preferable at least 21% by weight. When a combined styrene amount is less than 20% by weight, it tends that adequate improvement effect of grip performance can not be obtained. Also, the combined styrene amount is preferably at most 60% by weight, and more preferably at most 50% by weight. When the combined styrene amount is more than 60% by weight, a rubber becomes hard and wet grip performance tends to be lowered.
- an amount of SBR is preferably at least 3 parts by weight, and more preferably at least 5 parts by weight from the viewpoint that sufficient grip performance can be obtained.
- the amount of SBR is the most preferably 100 parts by weight.
- silica contained in the rubber composition can improve wet grip performance but it can not achieve both lowering of rolling resistance and improvement of dry grip performance.
- silica contained in the rubber composition several pieces of silica are combined to be silica having a chain structure (hereinafter, referred to as structure silica) so that at low tensile elongation (at low strain) such as at rolling with a low slip ratio, the number of stress concentration caused on the interface between a rubber and silica is reduced, and the ratio of stress that rubber matrix is shared is increased, thereby hysteresis loss is reduced and rolling resistance is lowered, and at high tensile elongation (at high strain) such as sudden brake and sharp curve, structure silica is oriented to a direction along a tread circumference to increase hysteresis loss and enhance dry grip performance.
- structure silica is oriented to a direction along a tread circumference to increase hysteresis loss and enhance dry grip performance.
- An average diameter (D) of structure silica is preferably at least 3 nm, and more preferably at least 4 nm.
- D is preferably at most 500 nm, and more preferably at most 400 nm.
- An average length (L) of structure silica is preferably at least 6 nm, and more preferably at least 10 nm.
- L is less than 6 nm, no effect to increase hysteresis loss due to the orientation of silica in a high tensile elongation area is obtained, and it tends that dry grip performance can not be increased.
- L is preferably at most 10,000 nm, and more preferably at most 7,000 nm.
- D is more than 10,000 nm, since stress is increased in a low tensile elongation area, hysteresis loss is increased, and it tends that rolling resistance is increased.
- An aspect ratio (L/D) of structure silica is at least 2, and preferably at least 2.5.
- L/D is less than 2
- L/D is at most 20, and preferably at most 17.5.
- L/D is more than 20, since stress is increased in a low tensile elongation area, hysteresis loss is increased and rolling resistance is increased.
- D, L and L/D are measured by observing silica dispersed in a vulcanized rubber composition by a transmission electron microscope.
- examples are organosilica sol IPA-ST-UP (available from Nissan Chemical Industries, Ltd.), high purity organo sol (available from Fuso Chemical Co., Ltd.), and Fine Cataloid F-120 (available from Catalysts & Chemicals Industries Co., Ltd.).
- An amount of structure silica is at least 5 parts by weight, preferably at least 10 parts by weight, and more preferably at least 15 parts by weight based on 100 parts by weight of the rubber component. When an amount of structure silica is less than 5 parts by weight, adequate improvement effects of rolling resistance, wet grip performance and dry grip performance due to containing structure silica can not be obtained. Also, an amount of structure silica is at most 150 parts by weight, preferably at most 120 parts by weight, and more preferably at most 100 parts by weight when an amount of structure silica is more than 150 parts by weight, rigidity of the rubber composition becomes high, and processability and wet grip performance are lowered.
- a silane coupling agent is compounded together with structure silica in the rubber composition of the present invention.
- the silane coupling agent there is no particular limitation as the silane coupling agent, those which have been used together with silica in the tire industry may be used, and examples are bis(3-triethoxysilylpropyl) polysulfide, bis(2-triethoxysilylethyl) polysulfide, bis(3-trimethoxysilylpropyl) polysulfide, bis(2-trimethoxysilylethyl) polysulfide, bis(4-triethoxysilylbutyl) polysulfide, and bis(4-trimethoxysilylbutyl) polysulfide, and these silane coupling agents may be used alone or in combination of at least two kinds.
- such a silane coupling agent as bis(3-triethoxysilylpropyl) disulfide is favorably used from the viewpoint of having both an
- An amount of a silane coupling agent is preferably at least 1 part by weight, and more preferably at least 2 parts by weight based on 100 parts by weight of structure silica.
- an amount of the silane coupling agent is less than 1 part by weight, since structure silica is hardly oriented to a direction along a circumference of a tread at high tensile elongation, and hysteresis loss is hardly increased, it tends that dry grip performance is lowered.
- an amount of the silane coupling agent is preferably at most 20 parts by weight, and more preferably at most 15 parts by weight. When an amount of the silane coupling agent is more than 20 parts by weight, improvement effects due to compounding a silane coupling agent can not be obtained, and cost thereof is increased.
- compounding agents generally used in the rubber industry such as various softening agents, various antioxidants, stearic acid, zinc oxide, a vulcanizing agent such as sulfur, and various vulcanization accelerators can be compounded into the rubber composition of the present invention.
- a kneaded article is obtained by kneading chemicals other than sulfur and vulcanization accelerators, for example, by a Banbury mixer (step 1). Then, sulfur and the vulcanization accelerators are added to the kneaded article and the mixture is kneaded by using, for example, a roller to obtain an unvulcanized rubber composition (step 2). Further, the rubber composition of the present invention is obtained by vulcanizing the unvulcanized rubber composition (step 3).
- step 1 a process of mixing chemicals other than sulfur and vulcanizing accelerators in toluene which is an excellent solvent of a rubber is known, however, in the case of this process, the number of silica particles constituting structure silica becomes excessively large, and it tend that rolling resistance is increased. As a result, L/D of structure silica becomes excessively large and rolling resistance tends to be increased.
- the rubber composition of the present invention is used for tires, and particularly, from the viewpoints that rolling resistance can be maintained at low tensile elongation and dry grip performance can be improved at high tensile elongation at the same time as excellent in wet grip performance, the rubber composition of the present invention is preferably used for a tread among tire parts, and more preferably used for a tread for tires of such as bus and truck for heavy load, general automobile tires, and racing-car tires.
- silica dispersed in vulcanized rubber compositions was observed by a transmission electron microscope, and a long diameter and a short diameter of arbitrary 30 particles were measured, and average values of these are respectively referred to as D and L, and L/D is calculated from D and L.
- Rubber test pieces formed into a cylindrical shape having a length of 20 mm and a diameter of 100 mm are prepared from the prepared vulcanized rubber compositions, and using a flat belt abrasion tester (FR5010) manufactured by Ueshima Seishakusho Co., Ltd., under the conditions of a speed at 20 km/h, a load of 4 kgf, an outside air temperature at 30° C., and a water temperature at 25° C., the maximum value of friction coefficient is read, which is detected at the time when a slip ratio of a sample for a wet road surface is changed from 0 to 70%.
- FR5010 flat belt abrasion tester manufactured by Ueshima Seishakusho Co., Ltd.
- Pneumatic tires of Example 1 and Comparative Examples 1 and 2 (tire size: 195/65R15) are prepared by forming the prepared unvulcanized rubber compositions into a tread shape, laminating with other tire parts, and vulcanizing under the condition at 170° C. for 20 minutes.
- Example 1 containing silica within the range of L/D from 2 to 20, both a vulcanized rubber composition and a pneumatic tire can improve both wet grip performance and dry grip performance without increasing rolling resistance property.
- both a vulcanized rubber composition and a pneumatic tire can improve dry grip performance, but wet grip performance and rolling resistance property were degenerated.
- a rubber composition in which wet grip performance and dry grip performance can be improved while rolling resistance is maintained by containing silica having a specific aspect ratio in the rubber composition, and a pneumatic tire using the same for a tread can be provided.
Abstract
A rubber composition, in which wet grip performance and dry grip performance can be improved without lowering rolling resistance property, and a pneumatic tire using the same for a tread. The rubber composition comprising 5 to 150 parts by weight of silica having an aspect ratio of 2 to 20 based on 100 parts by weight of a rubber component containing a diene rubber is provided.
Description
- The present invention relates to a rubber composition and a pneumatic tire.
- In recent years, from environmental issues such as global warming, social requirements for low fuel consumption efficiency have been enhanced, and development of low fuel efficient tire in which rolling resistance is lowered has been desired in response to low fuel consumption efficiency of an automobile.
- However, in general, a rubber composition lowering rolling resistance by reducing stress and hysteresis loss at low tensile elongation (at low strain) of a tire such as at low speed running decreases stress and hysteresis loss also at high tensile elongation (at high strain) of a tire such as sudden brake, and dry grip performance can not be improved. As a result, it has been difficult to have both lowering of rolling resistance and improvement in dry grip performance.
- As a method of reducing rolling resistance of a tire, an technique of substituting carbon black with silica is known. However, in the rubber composition compounding silica, it is known that dry grip performance is lowered, and when repeated running, grip performance is further more lowered due to decreasing rigidity of a rubber. Also, since a silanol group which is a surface functional group of silica forms a hydrogen bond, silica tends to coagulate each other, and there is a problem such that a Mooney viscosity of a rubber composition becomes high and processability such as extrusion is inferior since dispersion of silica particles in a rubber becomes insufficient.
- In order to solve theses problems, silica has been employed together with various coupling agents, a dispersing agent, a surface modifier and the like. For example, a silane coupling agent is considered to prevent silica particles from coagulating each other due to bonding with silanol groups on the surface of silica and to improve processability of the rubber composition. However, no rubber composition in which dry grip performance can be improved besides rolling resistance is lowered has been put into practical use yet.
- JP-A-8-337687 discloses a rubber composition lowering rolling resistance by compounding particulate silica and a silane coupling agent, however, the rubber composition is insufficient in the improvement effects of wet grip performance and dry grip performance, and thus, it still has a scope to be improved.
- An object of the present invention is to provide a rubber composition in which both wet grip performance and dry grip performance are improved, while rolling resistance is maintained, and a pneumatic tire using the same.
- The present invention relates to a rubber composition comprising 5 to 150 parts by weight of silica having an aspect ratio of 2 to 20 based on 100 parts by weight of a rubber component containing a diene rubber.
- The present invention also relates to a pneumatic tire, wherein the rubber composition is used for a tread.
- The rubber composition of the present invention comprises a rubber component and silica.
- The rubber component contains a diene rubber since it can improve wet grip performance and abrasion resistance. As a diene rubber, examples are rubbers generally used in the rubber industry such as a natural rubber (NR), a styrene butadiene rubber (SBR), a butadiene rubber (BR), an isoprene rubber (IR), a butyl rubber (IIR), an acrylonitrile butadiene rubber (NBR), an ethylene propylene diene rubber (EPDM) and a chloroprene rubber (CR), these are not particularly limited, and they may be used alone or in combination of at least two kinds. Among these, from the viewpoint of having adequate strength and excellent abrasion resistance, at least one kind of rubber selected from the group consisting of NR, SBR and BR is preferable, and SBR is more preferable.
- A combined styrene amount of SBR is preferably at least 20% by weight, and more preferable at least 21% by weight. When a combined styrene amount is less than 20% by weight, it tends that adequate improvement effect of grip performance can not be obtained. Also, the combined styrene amount is preferably at most 60% by weight, and more preferably at most 50% by weight. When the combined styrene amount is more than 60% by weight, a rubber becomes hard and wet grip performance tends to be lowered.
- When SBR is contained in the rubber component, since an amount of SBR is preferably at least 3 parts by weight, and more preferably at least 5 parts by weight from the viewpoint that sufficient grip performance can be obtained. In particular, the amount of SBR is the most preferably 100 parts by weight.
- Even though a rubber composition containing conventional particulate silica can improve wet grip performance but it can not achieve both lowering of rolling resistance and improvement of dry grip performance. However, in the present invention, as for silica contained in the rubber composition, several pieces of silica are combined to be silica having a chain structure (hereinafter, referred to as structure silica) so that at low tensile elongation (at low strain) such as at rolling with a low slip ratio, the number of stress concentration caused on the interface between a rubber and silica is reduced, and the ratio of stress that rubber matrix is shared is increased, thereby hysteresis loss is reduced and rolling resistance is lowered, and at high tensile elongation (at high strain) such as sudden brake and sharp curve, structure silica is oriented to a direction along a tread circumference to increase hysteresis loss and enhance dry grip performance.
- An average diameter (D) of structure silica is preferably at least 3 nm, and more preferably at least 4 nm. When the average diameter is less than 3 nm, a specific surface area is enlarged and stress shared on the interface between a rubber and silica may be increased even in a low tensile elongation area; namely, it tends that hysteresis loss is increased and rolling resistance is increased. Also, D is preferably at most 500 nm, and more preferably at most 400 nm. When D is more than 500 nm, since stress is not sufficiently increased in a high tensile elongation area and hysteresis loss is not increased, it tends that dry grip performance can not be increased.
- An average length (L) of structure silica is preferably at least 6 nm, and more preferably at least 10 nm. When L is less than 6 nm, no effect to increase hysteresis loss due to the orientation of silica in a high tensile elongation area is obtained, and it tends that dry grip performance can not be increased. Also, L is preferably at most 10,000 nm, and more preferably at most 7,000 nm. When D is more than 10,000 nm, since stress is increased in a low tensile elongation area, hysteresis loss is increased, and it tends that rolling resistance is increased.
- An aspect ratio (L/D) of structure silica is at least 2, and preferably at least 2.5. When L/D is less than 2, since stress is not sufficiently increased in a high tensile elongation area and also the hysteresis loss is not increased, dry grip performance can not be improved. Further, L/D is at most 20, and preferably at most 17.5. When L/D is more than 20, since stress is increased in a low tensile elongation area, hysteresis loss is increased and rolling resistance is increased.
- In the present invention, D, L and L/D are measured by observing silica dispersed in a vulcanized rubber composition by a transmission electron microscope.
- As specific examples of structure silica, examples are organosilica sol IPA-ST-UP (available from Nissan Chemical Industries, Ltd.), high purity organo sol (available from Fuso Chemical Co., Ltd.), and Fine Cataloid F-120 (available from Catalysts & Chemicals Industries Co., Ltd.).
- An amount of structure silica is at least 5 parts by weight, preferably at least 10 parts by weight, and more preferably at least 15 parts by weight based on 100 parts by weight of the rubber component. When an amount of structure silica is less than 5 parts by weight, adequate improvement effects of rolling resistance, wet grip performance and dry grip performance due to containing structure silica can not be obtained. Also, an amount of structure silica is at most 150 parts by weight, preferably at most 120 parts by weight, and more preferably at most 100 parts by weight when an amount of structure silica is more than 150 parts by weight, rigidity of the rubber composition becomes high, and processability and wet grip performance are lowered.
- It is preferable that a silane coupling agent is compounded together with structure silica in the rubber composition of the present invention. There is no particular limitation as the silane coupling agent, those which have been used together with silica in the tire industry may be used, and examples are bis(3-triethoxysilylpropyl) polysulfide, bis(2-triethoxysilylethyl) polysulfide, bis(3-trimethoxysilylpropyl) polysulfide, bis(2-trimethoxysilylethyl) polysulfide, bis(4-triethoxysilylbutyl) polysulfide, and bis(4-trimethoxysilylbutyl) polysulfide, and these silane coupling agents may be used alone or in combination of at least two kinds. Among these, such a silane coupling agent as bis(3-triethoxysilylpropyl) disulfide is favorably used from the viewpoint of having both an effect of adding an coupling agent and cost thereof.
- An amount of a silane coupling agent is preferably at least 1 part by weight, and more preferably at least 2 parts by weight based on 100 parts by weight of structure silica. When an amount of the silane coupling agent is less than 1 part by weight, since structure silica is hardly oriented to a direction along a circumference of a tread at high tensile elongation, and hysteresis loss is hardly increased, it tends that dry grip performance is lowered. Further, an amount of the silane coupling agent is preferably at most 20 parts by weight, and more preferably at most 15 parts by weight. When an amount of the silane coupling agent is more than 20 parts by weight, improvement effects due to compounding a silane coupling agent can not be obtained, and cost thereof is increased.
- In addition to the above-described rubber component, structure silica, and silane coupling agent, compounding agents generally used in the rubber industry such as various softening agents, various antioxidants, stearic acid, zinc oxide, a vulcanizing agent such as sulfur, and various vulcanization accelerators can be compounded into the rubber composition of the present invention.
- As for the rubber composition of the present invention, a kneaded article is obtained by kneading chemicals other than sulfur and vulcanization accelerators, for example, by a Banbury mixer (step 1). Then, sulfur and the vulcanization accelerators are added to the kneaded article and the mixture is kneaded by using, for example, a roller to obtain an unvulcanized rubber composition (step 2). Further, the rubber composition of the present invention is obtained by vulcanizing the unvulcanized rubber composition (step 3).
- In the step 1, a process of mixing chemicals other than sulfur and vulcanizing accelerators in toluene which is an excellent solvent of a rubber is known, however, in the case of this process, the number of silica particles constituting structure silica becomes excessively large, and it tend that rolling resistance is increased. As a result, L/D of structure silica becomes excessively large and rolling resistance tends to be increased.
- It is preferable that the rubber composition of the present invention is used for tires, and particularly, from the viewpoints that rolling resistance can be maintained at low tensile elongation and dry grip performance can be improved at high tensile elongation at the same time as excellent in wet grip performance, the rubber composition of the present invention is preferably used for a tread among tire parts, and more preferably used for a tread for tires of such as bus and truck for heavy load, general automobile tires, and racing-car tires.
- The present invention is explained in detail based on Examples, but the present invention is not limited only thereto.
- Then the chemicals used in the present invention are collectively explained.
- Styrene butadiene rubber (SBR): SBR1502 (combined styrene amount: 23.5% by weight) available from JSR Corporation
- Silica A: Organosilica sol IPA-ST-UP (chain silica sol dispersed in isopropanol, amount of silica: 15% by weight) available from Nissan Chemical Industries, Ltd.
- Silica B: Ultrasil VN3 (particulate silica) available from Degussa Co.
- Silane coupling agent: Si69 (bis(3-triethoxysilylpropyl) tetrasulfide) available from Degussa Co.
- Stearic acid: Stearic acid available from NOF Corporation
- Zinc oxide: Zinc oxide No. 1 available from Mitsui Mining & Smelting Co., Ltd.
- Sulfur: Sulfur powder available from Tsurumi Chemical Industry Co., Ltd.
- Vulcanization accelerator TBBS: NOCCELER NS (N-tert-butyl-2-benzothiazolylsulfenamide) available from Ouchi Shinko Chemical Industrial Co., Ltd.
- Vulcanization accelerator DPG: NOCCELER D (diphenylguanidine) available from Ouchi Shinko Chemical Industrial Co., Ltd.
- According to compounding prescriptions shown in Table 1, chemicals other than sulfur and vulcanization accelerators TBBS and DPG were kneaded under the condition at 100° C. for 5 minutes using a Banbury mixer to obtain a kneaded article. Then, sulfur and the vulcanization accelerators TBBS and DPG were added to the obtained kneaded article and the mixture was kneaded under the condition at 50° C. for 5 minutes using a roller to obtain unvulcanized rubber compositions. The obtained unvulcanized rubber compositions were press-vulcanized under the condition at 170° C. for 20 minutes to obtain vulcanized rubber compositions of Example 1 and Comparative Example 1 (preparation process 1).
- Only a rubber and silica were mixed in toluene first, not kneaded in a Banbury mixer, then, a rubber/silica masterbatch in which toluene was removed in a bath with a constant temperature at 70° C. was prepared, thereafter, a vulcanized rubber composition of Comparative Example 2 was obtained in the same manner as the preparation process 1 besides mixing a coupling agent, stearic acid and zinc oxide by using a roll (preparation process 2).
- (Average Diameter, Average Length, and Aspect Ratio of Silica)
- Regarding an average diameter (D), an average length (L), and an aspect ratio (L/D) of silica, silica dispersed in vulcanized rubber compositions was observed by a transmission electron microscope, and a long diameter and a short diameter of arbitrary 30 particles were measured, and average values of these are respectively referred to as D and L, and L/D is calculated from D and L.
- The above measured D, L and L/D of silica in the vulcanized rubber compositions for Example 1 and Comparative Examples 1 and 2 are shown in Table 1.
TABLE 1 Ex. 1 Com. Ex. 1 Com. Ex. 2 Kind of silica Silica A Silica B Silica A Preparation process of Preparation Preparation Preparation rubber composition process 1 process 1 process 2 Average diameter (D, nm) 13 20 13 Average length (L, nm) 42 24 329 Aspect ratio (L/D) 3.2 1.2 25.3
<Physical properties of vulcanized rubber composition> (Rolling resistance)
- Using a viscoelasticity spectrometer VES-FIII2 manufactured by Iwamoto Seisakusho Co., Ltd., loss tangents (tan δ) of the prepared vulcanized rubber compositions were measured under the conditions of an initial strain at 10%, a dynamic strain at 2%, a frequency at 10 Hz, and a temperature at 70° C. Then, rolling resistance of respective compositions was expressed as an index calculated in accordance with the following equation, assuming rolling resistance index of Comparative Example 1 as 100. It indicates that the larger the rolling resistance index is, the more rolling resistance is lowered, and the more excellent low exothermic property is.
(Rolling resistance index)=(Tan δ of Comparative Example 1)/(Tan δ of respective compositions)×100
(Wet Grip Performance) - Rubber test pieces formed into a cylindrical shape having a length of 20 mm and a diameter of 100 mm are prepared from the prepared vulcanized rubber compositions, and using a flat belt abrasion tester (FR5010) manufactured by Ueshima Seishakusho Co., Ltd., under the conditions of a speed at 20 km/h, a load of 4 kgf, an outside air temperature at 30° C., and a water temperature at 25° C., the maximum value of friction coefficient is read, which is detected at the time when a slip ratio of a sample for a wet road surface is changed from 0 to 70%. Then, wet grip performance of Example 1 and Comparative Examples 1 and 2 are expressed as an index calculated in accordance with the following equation, assuming wet grip index of Comparative Example 1 as 100. It indicates that the larger the wet grip index is, the more excellent wet grip performance is.
(Wet grip index)=(Maximum friction coefficient of respective compositions)/(Maximum friction coefficient of Comparative Example 1)×100
(Dry Grip Performance) - Rubber test pieces formed into a cylindrical shape having a length of 20 mm and a diameter of 100 mm were prepared from the prepared vulcanized rubber compositions, and using a flat belt abrasion tester (FR5010) manufactured by Ueshima Seishakusho Co., Ltd., under the conditions of a speed at 20 km/h, a load of 4 kgf, and an outside air temperature at 30° C., the maximum value of friction coefficient is read, which is detected at the time when a slip ratio of a sample for a dry road surface is changed from 0 to 50%. Then, dry grip performance of Example 1 and Comparative Examples 1 and 2 are expressed as an index calculated in accordance with the following equation, assuming dry grip index of Comparative Example 1 as 100. It indicates that the larger the dry grip index is, the more excellent dry grip performance is.
(Dry grip index)=(Maximum friction coefficient of respective compositions)/(Maximum friction coefficient of Comparative Example 1)×100
<Properties of Pneumatic Tire> - Pneumatic tires of Example 1 and Comparative Examples 1 and 2 (tire size: 195/65R15) are prepared by forming the prepared unvulcanized rubber compositions into a tread shape, laminating with other tire parts, and vulcanizing under the condition at 170° C. for 20 minutes.
- (Rolling Resistance Property)
- The maximum friction coefficient generated between a contact surface and the pneumatic tire is measured by rotating the prepared pneumatic tire at a speed of 80 km/h under the conditions of a tire air pressure at 2.00 kPa, and a load of 400 kgf, using a drum testing machine, and rolling resistance property of Example 1 and Comparative Examples 1 and 2 are expressed as an index calculated in accordance with the following equation, assuming rolling resistance index of Comparative Example 1 as 100. It indicates that the larger the rolling resistance index is, the more rolling resistance is lowered.
(Rolling resistance index)=(Maximum friction coefficient of Comparative Example 1)/(Maximum friction coefficient of respective compositions)×100
(Wet Grip Performance) - The prepared pneumatic tires are mounted on a automobile for tests, actual running is carried out on a test course having a wet asphalt road surface. In this case, the automobile was run at 40 km/h, and the maximum friction coefficient (μ) during a period from the application of brake and stop is measured. Then, wet grip performance of Example 1 and Comparative Examples 1 and 2 are expressed as an index calculated in accordance with the following equation, assuming wet grip index of Comparative Example 1 as 100. It indicates that the larger the index is, the more excellent the wet grip performance is.
(Wet grip index)=(Wet grip performance of respective compositions)/(Wet grip performance of Comparative Example 1)×100
(Dry Grip Performance) - The prepared pneumatic tires are mounted on a automobile for tests, actual running is carried out on a test course having a dry asphalt road surface. In this case, the automobile was run at 40 km/h, and the maximum friction coefficient (μ) during a period from the application of brake and stop is measured. Then, dry grip performance of Example 1 and Comparative Examples 1 and 2 are expressed as an index calculated in accordance with the following equation, assuming dry grip index of Comparative Example 1 as 100. It indicates that the larger the index is, the more excellent the dry grip performance is.
(Dry grip index)=(Dry grip performance of respective compositions)/(Dry grip performance of Comparative Example 1)×100 - Measurement results of the above-described tests are shown in Table 2.
TABLE 2 Com. Com. Ex. 1 Ex. 1 Ex. 2 Amounts (part by weight) SBR 100 100 100 Silica A (Preparation process 1) 50 — — Silica B (Preparation process 1) — 50 — Silica A (Preparation process 2) — — 50 Silane coupling agent 4 4 4 Stearic acid 2 2 2 Zinc oxide 3 3 3 Sulfur 1.5 1.5 1.5 Vulcanization accelerator TBBS 1 1 1 Vulcanization accelerator DPG 0.5 0.5 0.5 Test results of rubber composition — — — Rolling resistance index 100 100 95 Wet grip index 103 100 80 Dry grip index 108 100 103 Test results of tire using — — — rubber composition Rolling resistance index 101 100 90 Wet grip index 105 100 82 Dry grip index 110 100 105 - Among the vulcanized rubber compositions, in Example 1 containing silica within the range of L/D from 2 to 20, both a vulcanized rubber composition and a pneumatic tire can improve both wet grip performance and dry grip performance without increasing rolling resistance property.
- Among the vulcanized rubber compositions, in Comparative Example 1 containing silica having small L/D, both a vulcanized rubber composition and a pneumatic tire can not obtain sufficient wet grip performance and dry grip performance.
- Among the vulcanized rubber compositions, in Comparative Example 2 containing silica having large L/D, both a vulcanized rubber composition and a pneumatic tire can improve dry grip performance, but wet grip performance and rolling resistance property were degenerated.
- According to the present invention, a rubber composition, in which wet grip performance and dry grip performance can be improved while rolling resistance is maintained by containing silica having a specific aspect ratio in the rubber composition, and a pneumatic tire using the same for a tread can be provided.
Claims (2)
1. A rubber composition comprising 5 to 150 parts by weight of silica having an aspect ratio of 2 to 20 based on 100 parts by weight of a rubber component containing a diene rubber.
2. A pneumatic tire, wherein the rubber composition of claim 1 is used for a tread.
Priority Applications (1)
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US11/583,159 US7411016B2 (en) | 2005-11-14 | 2006-10-19 | Rubber composition and pneumatic tire using the same for tread |
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JP2005328604 | 2005-11-14 | ||
JP2005-328604 | 2005-11-14 |
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US11/583,159 Continuation-In-Part US7411016B2 (en) | 2005-11-14 | 2006-10-19 | Rubber composition and pneumatic tire using the same for tread |
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US20070112121A1 true US20070112121A1 (en) | 2007-05-17 |
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US11/541,643 Abandoned US20070112121A1 (en) | 2005-11-14 | 2006-10-03 | Rubber composition and pneumatic tire using the same for tread |
US11/583,159 Active US7411016B2 (en) | 2005-11-14 | 2006-10-19 | Rubber composition and pneumatic tire using the same for tread |
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US11/583,159 Active US7411016B2 (en) | 2005-11-14 | 2006-10-19 | Rubber composition and pneumatic tire using the same for tread |
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US (2) | US20070112121A1 (en) |
EP (1) | EP1790501B1 (en) |
JP (1) | JP4790562B2 (en) |
CN (1) | CN1966556B (en) |
DE (1) | DE602006001625D1 (en) |
RU (1) | RU2338761C2 (en) |
Cited By (4)
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US20080161458A1 (en) * | 2006-12-29 | 2008-07-03 | Shaun Fox | Elastomeric composition containing multiple silane coupling agents |
US20140352418A1 (en) * | 2013-05-31 | 2014-12-04 | E I Du Pont De Nemours And Company | Method and specimen for testing braking in tires |
US20140366617A1 (en) * | 2013-06-14 | 2014-12-18 | E I Du Pont De Nemours And Company | Method and specimen for testing handling in tires |
US20160368231A1 (en) * | 2015-06-16 | 2016-12-22 | The Goodyear Tire & Rubber Company | Method of securing splices in curable rubber articles |
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US10023723B2 (en) * | 2007-06-05 | 2018-07-17 | Momentive Performance Materials Inc. | Process for preparing rubber compositions and articles made therefrom |
JP5612243B2 (en) * | 2007-07-25 | 2014-10-22 | 住友ゴム工業株式会社 | Rubber composition for tire and pneumatic tire |
US8182626B2 (en) * | 2008-10-30 | 2012-05-22 | Continental Ag | Tire composition with improved vulcanizing agent |
FR2969164B1 (en) * | 2010-12-17 | 2014-04-11 | Michelin Soc Tech | ELASTOMERIC COMPOSITION HAVING VERY GOOD DISPERSION OF THE LOAD IN THE ELASTOMERIC MATRIX |
WO2012140979A1 (en) * | 2011-04-11 | 2012-10-18 | 住友ゴム工業株式会社 | Rubber composition for tires and pneumatic tires |
JP2012224769A (en) * | 2011-04-20 | 2012-11-15 | Sumitomo Rubber Ind Ltd | Rubber composition for tire, and pneumatic tire |
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JP2013006903A (en) * | 2011-06-22 | 2013-01-10 | Sumitomo Rubber Ind Ltd | Rubber composition, and pneumatic tire |
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JP2013006904A (en) * | 2011-06-22 | 2013-01-10 | Sumitomo Rubber Ind Ltd | Rubber composition and pneumatic tire manufactured using the same |
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JP2000119445A (en) | 1998-10-14 | 2000-04-25 | Sumitomo Rubber Ind Ltd | Tire tread rubber composition |
JP4405629B2 (en) | 1998-11-09 | 2010-01-27 | 株式会社ブリヂストン | Rubber composition for tire tread |
JP4588177B2 (en) | 2000-06-30 | 2010-11-24 | 株式会社ブリヂストン | Pneumatic tire and manufacturing method thereof |
US20040030027A1 (en) * | 2000-09-06 | 2004-02-12 | Tomohisa Konno | Diene rubber/inorganic compound composite and method for producing the same and rubber composition |
EP1260544B1 (en) * | 2001-05-24 | 2007-05-09 | Sumitomo Rubber Industries Ltd. | Rubber composition for tire tread and pneumatic tire using the same |
JP2003155384A (en) * | 2001-11-21 | 2003-05-27 | Toyo Tire & Rubber Co Ltd | Rubber composition for tire tread |
JP2003155383A (en) * | 2001-11-21 | 2003-05-27 | Toyo Tire & Rubber Co Ltd | Rubber composition for tire tread |
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2006
- 2006-10-03 US US11/541,643 patent/US20070112121A1/en not_active Abandoned
- 2006-10-12 JP JP2006279010A patent/JP4790562B2/en active Active
- 2006-10-18 EP EP06021824A patent/EP1790501B1/en not_active Expired - Fee Related
- 2006-10-18 DE DE602006001625T patent/DE602006001625D1/en active Active
- 2006-10-19 US US11/583,159 patent/US7411016B2/en active Active
- 2006-11-08 CN CN2006101484248A patent/CN1966556B/en not_active Expired - Fee Related
- 2006-11-13 RU RU2006139788/04A patent/RU2338761C2/en not_active IP Right Cessation
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US20020128370A1 (en) * | 2000-11-29 | 2002-09-12 | Colvin Howard Allen | Reinforced silica/elastomer composite |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
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US20080161458A1 (en) * | 2006-12-29 | 2008-07-03 | Shaun Fox | Elastomeric composition containing multiple silane coupling agents |
US7592384B2 (en) * | 2006-12-29 | 2009-09-22 | Shaun Fox | Elatomeric composition containing multiple silane coupling agents |
US20140352418A1 (en) * | 2013-05-31 | 2014-12-04 | E I Du Pont De Nemours And Company | Method and specimen for testing braking in tires |
US20140366617A1 (en) * | 2013-06-14 | 2014-12-18 | E I Du Pont De Nemours And Company | Method and specimen for testing handling in tires |
US20160368231A1 (en) * | 2015-06-16 | 2016-12-22 | The Goodyear Tire & Rubber Company | Method of securing splices in curable rubber articles |
CN106256849A (en) * | 2015-06-16 | 2016-12-28 | 固特异轮胎和橡胶公司 | The method of fixing curable rubber goods center tap |
Also Published As
Publication number | Publication date |
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US20070112119A1 (en) | 2007-05-17 |
EP1790501A1 (en) | 2007-05-30 |
JP4790562B2 (en) | 2011-10-12 |
US7411016B2 (en) | 2008-08-12 |
DE602006001625D1 (en) | 2008-08-14 |
JP2007154158A (en) | 2007-06-21 |
RU2006139788A (en) | 2008-05-20 |
CN1966556B (en) | 2010-11-03 |
EP1790501B1 (en) | 2008-07-02 |
RU2338761C2 (en) | 2008-11-20 |
CN1966556A (en) | 2007-05-23 |
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