Diene rubber compounding agent and rubber composition

Abstract

When added to a rubber composition, a diene rubber compounding agent comprising (A) a silicone resin represented by formula (1) gives a rubber composition capable of achieving desired hardness, tensile properties, and durability without deteriorating the processability, wear resistance, and fuel consumption reduction performance of the composition. (SiO4 / 2) a (R1SiO3 / 2) b (R12SiO2 / 2) c (R13SiO1 / 2) d (R2O1 / 2) e (1) (In the formula, R1 each independently represents a hydrogen atom, or a C1-8 alkyl group, aralkyl group, or aryl group which may be substituted by a halogen atom, at least 50 mol% of R1 represents a methyl group, R2 represents a hydrogen atom, methyl group, ethyl group, n-propyl group, isopropyl group, or acetyl group, at least 20 mol% of R2 represents a hydrogen atom, a, b, c, and d represent numbers satisfying 0 < = a < 1, 0 < b < = 1, 0 < = c < 1, 0 < = d < 1, and a + b + c + d = 1, and e represents a number satisfying 0 < = e < = 2).

Description

TECHNICAL FIELD

[0001] The present application relates to a compounding agent for diene rubber and a rubber composition. BACKGROUND

[0002] Silica-filled tires have excellent properties in automobile use, particularly excellent wear resistance, rolling resistance and wet grip. Improvement of these properties is closely related to improvement of low fuel consumption of the tires, and therefore, in the industry of passenger car tires using solution polymerized styrene butadiene rubber (S-SBR), research has been actively conducted recently.

[0003] A silica-filled rubber composition, although reducing the rolling resistance of the tire and improving the wet grip, has a high unvulcanized viscosity, requires multi-stage mixing and the like, and has problems in workability.

[0004] Therefore, in a rubber composition simply compounded with an inorganic filler such as silica, problems of insufficient dispersion of the filler, and a large decrease in breaking strength and wear resistance occur. Therefore, in order to improve the dispersibility of the inorganic filler in rubber, and to chemically bond the filler to the rubber matrix, a sulfur-containing organosilicon compound is required.

[0005] As a sulfur-containing organosilicon compound used as a rubber compounding agent, it is known that a compound containing an alkoxysilyl group and a polythioether silyl group in the molecule, such as bis-triethoxysilylpropyl tetrasulfide, bis-triethoxysilylpropyl disulfide, and the like, is effective (see Patent Documents 1 to 4).

[0006] In order to improve the dispersibility of silica as an inorganic filler, and to improve the low fuel consumption characteristics, various compounds containing an alkoxysilyl group have been developed, and although the low fuel consumption characteristics are improved, there is a problem that the hardness and tensile properties are not improved. Therefore, a material that improves the hardness and tensile properties without deteriorating the processability and low fuel consumption characteristics is required.

[0007] In this regard, in Patent Document 5, a method of improving the hardness and tensile properties by adding an organosilicon resin containing a silanol group to an organic elastomer is proposed, but further improvement in hardness, tensile properties and durability is required.

[0008] PRIOR ART DOCUMENTS

[0009] PATENT DOCUMENTS

[0010] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-525230

[0011] Patent Document 2: Japanese Patent Application Laid-Open No. 2004-18511

[0012] Patent Document 3: Japanese Patent Application Laid-Open No. 2002-145890

[0013] Patent Literature 4: Japanese Patent Application Laid-Open (JP-A) No. 2000-103795

[0014] Patent Literature 5: Japanese Patent Application Laid-Open (JP-A) No. 2011-504956 SUMMARY

[0015] PROBLEMS TO BE SOLVED BY THE INVENTION

[0016] The present application has been achieved in view of the above-described actual circumstances, and aims to provide a rubber compounding agent which, when added to a rubber composition, does not deteriorate the processability, wear resistance, and low fuel consumption performance of the composition, and imparts a rubber composition with a desired hardness, tensile properties, and durability, a rubber composition in which the rubber compounding agent is compounded, and a tire formed from the rubber composition.

[0017] MEANS FOR SOLVING THE PROBLEMS

[0018] The present inventors have intensively studied in order to solve the above-described problems, and as a result, have found that a specific silicone resin is suitable as a rubber compounding agent, and that a tire obtained from a rubber composition containing the rubber compounding agent does not deteriorate the processability, wear resistance, and low fuel consumption performance of the composition, and imparts a desired hardness, tensile properties, and durability, and have completed the present application.

[0019] That is, the present application provides:

[0020] 1. A rubber compounding agent for diene rubbers, comprising (A) a silicone resin represented by the following formula (1),

[0021] (SiO 4 / 2 ) a (R 1 SiO 3 / 2 ) b (R 1 2SiO 2 / 2 ) c (R 1 3SiO 1 / 2 ) d (R 2 O 1 / 2 ) e (1)

[0022] in the formula, R 1 each independently represents a hydrogen atom, or an alkyl group, aralkyl group, or aryl group having 1 to 8 carbon atoms which can be substituted with a halogen atom, at least 50 mole % of R 1 are methyl groups, R 2 represents a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, or an acetyl group, and R 2at least 20 mole % of the R

[0023] 2. The compounding agent for diene rubber according to 1, wherein the b is a number satisfying 0.4 ≤ b ≤ 1.

[0024] 3. The compounding agent for diene rubber according to 2, wherein the b is 1.

[0025] 4. The compounding agent for diene rubber according to 1, wherein the silicone resin is a solid at 25°C.

[0026] 5. The compounding agent for diene rubber according to any one of 1 to 4, further comprising (B) a silicone compound having one or more selected from the group consisting of a polythioether group, a thioester group and a mercapto group, and an alkoxysilyl group.

[0027] 6. A rubber composition comprising:

[0028] (A) a silicone resin represented by the following formula (1),

[0029] (SiO 4 / 2 ) a (R 1 SiO 3 / 2 ) b (R 1 2SiO 2 / 2 ) c (R 1 3SiO 1 / 2 ) d (R 2 O 1 / 2 ) e (1)

[0030] wherein R 1 each independently represents a hydrogen atom, or an alkyl group having 1 to 8 carbon atoms, an aralkyl group or an aryl group which can be substituted with a halogen atom, R 1 at least 50 mole % of the R 2 represents a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an i-propyl group or an acetyl group, R 2 at least 20 mole % of the R

[0031] (B) a silicone compound having one or more selected from the group consisting of a polythioether group, a thioester group and a mercapto group, and an alkoxysilyl group,

[0032] (C) diene rubber, and

[0033] (D) inorganic filler.

[0034] 7. Tire molded from the rubber composition according to 6.

[0035] Effects of the Invention

[0036] The rubber composition incorporating the rubber additive of the present invention is excellent in processability, and the tire formed using the rubber composition can achieve the required hardness, tensile properties and durability without deteriorating the wear resistance and low fuel consumption. DETAILED DESCRIPTION

[0037] The present invention is specifically described below.

[0038] [Rubber additive]

[0039] The rubber additive of the present invention comprises the following (A) component.

[0040] [1] (A) Silicone resin

[0041] The (A) component is a silicone resin having the following structural unit ratio represented by the following formula (1).

[0042] (SiO 4 / 2 ) a (R 1 SiO 3 / 2 ) b (R 1 2SiO 2 / 2 ) c (R 1 3SiO 1 / 2 ) d (R 2 O 1 / 2 ) e (1)

[0043] In formula (1), R 1 each independently represents a hydrogen atom, or an alkyl group having 1 to 8 carbon atoms, aralkyl group or aryl group which can be substituted with a halogen atom.

[0044] As the alkyl group having 1 to 8 carbon atoms of R 1 , straight chain, branched chain, cyclic chain are all possible, and as specific examples thereof, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, neopentyl group, n-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, etc. can be mentioned, and alkyl group having 1 to 3 carbon atoms is preferred, and methyl group, ethyl group, propyl group is more preferred.

[0045] As the aralkyl group, an aralkyl group having 7 to 20 carbon atoms is preferred, and as specific examples thereof, a benzyl group, a phenylethyl group, and the like can be given.

[0046] As the aryl group, an aryl group having 6 to 18 carbon atoms is preferred, and as specific examples thereof, unsubstituted aryl groups such as a phenyl group, a naphthyl group; alkylaryl groups having 7 to 18 carbon atoms such as a tolyl group, a xylyl group, an ethylphenyl group, a propylphenyl group, a butylphenyl group, a pentylphenyl group, a hexylphenyl group, a heptylphenyl group, an octylphenyl group, a nonylphenyl group, a decylphenyl group, an undecylphenyl group, a dodecylphenyl group, and the like; and a phenyl group are given, with a phenyl group being preferred.

[0047] In the above formula (1), R 1 More than 50 mole% of R 1 If less than 50 mole% of R

[0048] Further, in the above alkyl group, aralkyl group, and aryl group, a part or all of the hydrogen atoms thereof can be substituted with halogen atoms (fluorine, chlorine, bromine, iodine atoms), and as specific examples thereof, a chloromethyl group, a chloropropyl group, a bromoethyl group, a trifluoropropyl group, a chlorophenyl group, a bromophenyl group, and the like can be given.

[0049] In the above formula (1), R 2 represents a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, or an acetyl group, with a hydrogen atom being preferred. R 2 More than 50 mole% of R

[0050] a, b, c, d are numbers satisfying 0≤a<1, 0

[0051] In order to improve the hardness, the tensile properties, and the durability of the rubber properties, it is necessary that 0

[0052] Further, e is a number satisfying 0≤e≤2, and in order to improve the hardness, the tensile properties, and the durability of the rubber properties, it is preferred that 0.05≤e≤1, and more preferably 0.10≤e≤1.

[0053] In the rubber compounding agent of the present application, the (A) silicone resin can be a single composition, or a mixture of a plurality of compounds having different compositions.

[0054] The weight average molecular weight of the (A) silicone resin of the present application is not particularly limited, and the polystyrene-conversion weight average molecular weight obtained by gel permeation chromatography (GPC) is preferably 500 to 500,000, more preferably 1,000 to 300,000. If the weight average molecular weight is less than 500, sometimes the hardness and tensile properties are not improved.

[0055] Further, the (A) silicone resin is preferably solid at 25°C. By being solid, mixing in the tire composition becomes easy.

[0056] The softening point of the (A) silicone resin is preferably 60 to 120°C. Further, the softening point is a value measured by the ring and ball method according to JIS K2207:2006.

[0057] The (A) silicone resin is preferably 95% by mass or more, in terms of safety during mixing of the rubber composition, of non-volatile matter not including solvents and the like.

[0058] [2] (B) Component

[0059] In the rubber compounding agent of the present application, in addition to the above (A) component, a (B) silicone compound having one or more selected from the group consisting of a polythioether group, a thioester group, and a mercapto group, and an alkoxysilyl group can be used.

[0060] As the (B) component, there is no particular limitation as long as it is a compound having such a functional group, and for example, any of the silane coupling agents conventionally known to be compounded in rubber compositions for tire and the like can be used.

[0061] As specific examples of the above silane coupling agent, polythioether-based silicone compounds such as bis-(3-bistrimethoxysilylpropyl)-tetrasulfide, bis-(3-bistrimethoxysilylpropyl)-disulfide; mercapto-based silicone compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane; thioester-based silicone compounds such as 3-octanoylthiopropyltriethoxysilane, 3-propionylthiopropyltrimethoxysilane; and the like can be listed.

[0062] Further, a reactant of the above silicone compound having a sulfur atom and an alcohol containing a polyether group, a hydrolysis condensate of these silicone compounds, a co-hydrolysis condensate of these silicone compounds and other silicone compounds having an alkoxysilyl group, and the like can also be used.

[0063] Further, the (B) component can be used alone as one kind, or two or more kinds can be used in combination.

[0064] In the case where the rubber compounding agent of the present application contains the (B) component, the blending ratio of the above-mentioned (A) component and (B) component is not particularly limited, and, expressed in terms of mass ratio, (B) / (A) = 10 / 90 to 95 / 5 is preferred, and 30 / 70 to 95 / 5 is more preferred.

[0065] The above-mentioned composition of the present application containing the (A) silicone resin can be used as it is as a rubber compounding agent, but a product obtained by mixing the composition and at least one powder can also be used as a rubber compounding agent.

[0066] As specific examples of the powder, carbon black, talc, calcium carbonate, stearic acid, silica, aluminum hydroxide, aluminum oxide, magnesium hydroxide, etc. can be given.

[0067] Of these, from the viewpoint of reinforcement, silica and aluminum hydroxide are preferred, and silica is more preferred.

[0068] In the case where a powder is used, in terms of the amount thereof to be blended, the mass ratio of the amount of the above-mentioned (A) component to the total amount of the powder (Y), or, in the case where a (B) component is contained, the mass ratio of the total amount (X) of the (A) component and (B) component to the total amount of the powder (Y) ((X) / (Y)) is preferably 70 / 30 to 5 / 95, taking into account the handling properties, transportation cost, etc. of the rubber compounding agent.

[0069] Further, the rubber compounding agent of the present application can be a product mixed with a fatty acid, a fatty acid salt, polyethylene, polypropylene, polyoxyalkylene, polyester, polyurethane, polystyrene, polybutadiene, polyisoprene, natural rubber, styrene-butadiene copolymer, etc. organic polymer, rubber, and a product compounded with various additives generally used in tire use, other general rubber use, such as vulcanizing agent, crosslinking agent, vulcanization accelerator, crosslinking accelerator, various oils, antioxidant, filler, plasticizer, etc.

[0070] In addition, as its form, it can be in a liquid state, or in a solid state, or in a product further diluted in an organic solvent, and in addition, it can be an emulsified product.

[0071] [Rubber composition]

[0072] The rubber composition of the present application contains the above-mentioned (A) component and (B) component, a silicone compound having an alkoxysilyl group, a (C) diene-based rubber, and a (D) inorganic filler.

[0073] As for the blending amount of the (A) component and the (B) component in the rubber composition of the present application, in view of the balance of the physical properties of the resulting rubber, the degree of effects exerted, and economy, etc., the blending amount of the (A) component is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, and the blending amount of the (B) component is preferably 1 to 30 parts by mass, more preferably 5 to 20 parts by mass, relative to 100 parts by mass of the (D) component which will be described later.

[0074] [3] (C) component

[0075] As the diene rubber of the (C) component, any rubber generally used in the past in various rubber compositions can be used, and as specific examples thereof, various isoprene rubbers (IR) such as natural rubber, various styrene-butadiene copolymer rubbers (SBR), various polybutadiene rubbers (BR), acrylonitrile-butadiene copolymer rubbers (NBR), and the like can be listed, and these can be used alone as one kind or in combination of two or more kinds.

[0076] In addition, in addition to the diene rubber, non-diene rubber such as butyl rubber (IIR), ethylene-propylene copolymer rubber (EPR, EPDM), and the like can be used in combination.

[0077] [4] (D) component

[0078] As the inorganic filler of the (D) component, for example, inorganic fillers generally used in the tire industry such as silica, carbon black, aluminum hydroxide, alumina (aluminum oxide), calcium carbonate, talc, clay, and the like can be listed, and these can be used alone as one kind or in combination of two or more kinds.

[0079] Among these, the rubber composition of the present application preferably contains silica and carbon black.

[0080] As the carbon black, for example, carbon black generally used in the tire industry such as GPF, FEF, HAF, ISAF, SAF, and the like can be listed.

[0081] As the silica, for example, silica generally used in the tire industry such as silica prepared by a dry method (anhydrous silica), silica prepared by a wet method (hydrous silica), and the like can be listed, and among these, silica prepared by a wet method is preferred due to the presence of a large number of silanol groups.

[0082] In particular, the silica is preferably silica having a nitrogen adsorption specific surface area (N2SA) of 70 m 2 / g or more, more preferably 100 m 2 / g or more. Further, there is no particular limitation on the upper limit of the N2SA, and from the viewpoint of ease of handling, etc., 500 m 2 / g or less, more preferably 400 m2 / g or less.

[0083] The blending amount of the component (D) in the rubber composition of the present application is preferably 5 to 200 parts by mass, more preferably 10 to 150 parts by mass, and further preferably 20 to 130 parts by mass, relative to 100 parts by mass of the component (C), from the viewpoints of dispersibility, low fuel consumption, and molding processability.

[0084] Further, in the rubber composition of the present application, in addition to the components (A) to (D) described above, various additives generally blended in tires and other rubbers, such as sulfur, a crosslinking agent, a vulcanization accelerator, a crosslinking accelerator, various oils, an antioxidant, a plasticizer, various resins, a wax, zinc oxide, and the like, can be blended. The blending amount of these additives can be set to the conventional general blending amount, as long as the object of the present application is not violated.

[0085] As the sulfur, powder sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur, and the like, which are generally used in the rubber industry, can be exemplified. These can be used alone or in combination of two or more. As these sulfurs, for example, products available from Tsurumi Chemical Industry (Co., Ltd.), Kagawa Sulfur (Co., Ltd.), Shikoku Kasei Industry (Co., Ltd.), Flexsys, Japan Dry Distillation Industry (Co., Ltd.), and Hosoi Chemical Industry (Co., Ltd.) can be used.

[0086] In the case where sulfur is blended, the blending amount is preferably 0.1 parts by mass or more and 5.0 parts by mass or less, more preferably 0.3 parts by mass or more and 3.0 parts by mass or less, and further preferably 0.5 parts by mass or more and 2.0 parts by mass or less, relative to 100 parts by mass of the component (C). If it is within the above range, the balance between the tensile properties and the wear resistance is good.

[0087] [Rubber product (tire)]

[0088] As the rubber composition of the present application described above, by using the components (A) to (D) and other components described above to produce a composition by a general method, and by vulcanizing or crosslinking the same, for example, it can be used in the production of a rubber product such as a tire. In particular, in the case of producing a tire, it is preferable to use the rubber composition of the present application for a tread.

[0089] The tire obtained using the rubber composition of the present application is excellent in wear resistance in addition to the reduction in rolling resistance, and thus can achieve the desired low fuel consumption, and is also excellent in durability.

[0090] Further, the structure of the tire can be set to a structure known in the art, and the production method thereof can also be a method known in the art. In the case of a pneumatic tire, as the gas filled in the tire, in addition to air and air adjusted in oxygen partial pressure, a non-reactive gas such as nitrogen, argon, and helium can be used.

[0091] Examples

[0092] The present application is more specifically explained by the following enumerated examples and comparative examples, but is not limited to these examples.

[0093] [Examples 1-1 to 1-6, Comparative Examples 1-1 to 1-5]

[0094] The natural rubber described in Table 1 was mixed for 60 seconds using a 4L internal mixer (MIXTRON, Kobe Steel, Ltd.).

[0095] Next, the carbon black, silica, silicone resin, stearic acid, antioxidant, resin, and wax described in Table 1 were added, and the internal temperature was raised to 150°C, and discharged. Then, extension was performed using a roll. The obtained rubber composition was again mixed using an internal mixer (MIXTRON, Kobe Steel, Ltd.) until the internal temperature became 145°C, and discharged, and extension was performed using a roll. The zinc oxide, vulcanization accelerator, and sulfur described in Table 1 were added thereto, and mixed, and a rubber composition was obtained.

[0096] Natural Rubber: RSS #3

[0097] Carbon Black: Seast 9H (produced by Tokai Carbon Co., Ltd.)

[0098] Silica: Nipsil AQ (produced by Nippon Silica Chemical Co., Ltd.)

[0099] Thioether-based silane: KBE-846 (produced by Shin-Etsu Chemical Co., Ltd., bis(triethoxysilylpropyl) tetrasulfide)

[0100] Silicone Resin (A-1): a silicone resin represented by (R 1 SiO 3 / 2 ) 1.00 (R 2 O 1 / 2 ) 0.21 , R 1 is a methyl group (100 mol%), R 2 is a hydrogen atom (60 mol%), a methyl group (40 mol%), has a weight average molecular weight of 3000, a softening point of 75°C, and is a solid at 25°C

[0101] Silicone Resin (A-2): a silicone resin represented by (R 1 SiO 3 / 2 ) 1.00 (R 2 O 1 / 2 ) 0.12 , R 1 is a methyl group (80 mol%), a phenyl group (20 mol%), R 2Silicone resin (A-2): a silicone resin having a number average molecular weight of 3500, a softening point of 77°C, and being solid at 25°C, wherein R

[0102] Silicone resin (A-3): a silicone resin having a number average molecular weight of 3500, a softening point of 77°C, and being solid at 25°C, wherein R 1 SiO 3 / 2 ) 1.00 (R 2 O 1 / 2 ) 0.12 represents, R 1 is a methyl group (80 mole %), a n-propyl group (20 mole %), R 2 is a hydrogen atom (60 mole %), a methyl group (40 mole %), a number average molecular weight of 3500, a softening point of 77°C, and being solid at 25°C

[0103] Silicone resin (A-4): a silicone resin having a number average molecular weight of 3500, a softening point of 77°C, and being solid at 25°C, wherein R 1 SiO 3 / 2 ) 1.00 (R 2 O 1 / 2 ) 0.12 represents, R 1 is a methyl group (60 mole %), a phenyl group (40 mole %), R 2 is a hydrogen atom (60 mole %), a methyl group (40 mole %), a number average molecular weight of 3700, a softening point of 79°C, and being solid at 25°C

[0104] Silicone resin (A-5): a silicone resin having a number average molecular weight of 3500, a softening point of 77°C, and being solid at 25°C, wherein R 1 SiO 3 / 2 ) 1.00 (R 2 O 1 / 2 ) 0.12 represents, R 1 is a methyl group (40 mole %), a phenyl group (60 mole %), R 2 is a hydrogen atom (60 mole %), a methyl group (40 mole %), a number average molecular weight of 3700, a softening point of 79°C, and being solid at 25°C

[0105] Silicone resin (A-6): a silicone resin having a number average molecular weight of 3500, a softening point of 77°C, and being solid at 25°C, wherein R 1 SiO 3 / 2 ) 1.00 (R 2 O 1 / 2 ) 0.61 represents, R 1 is a phenyl group (70 mole %) and a n-propyl group (30 mole %), R 2 is a hydrogen atom (60 mole %), a methyl group (40 mole %), a number average molecular weight of 4500, a softening point of 75°C, and being solid at 25°C

[0106] Silicone Resin (A-7): A silicone resin represented by (R 1 SiO 3 / 2 ) 1.00 (R 2 O 1 / 2 ) 0.12 , R 1 is a n-propyl group (100 mole %), R 2 is a hydrogen atom (60 mole %), a methyl group (40 mole %), has a weight average molecular weight of 3000, a softening point of 70°C, and is a solid at 25°C

[0107] Silicone Resin (A-8): A silicone resin represented by (R 1 SiO 3 / 2 ) 1.00 (R 2 O 1 / 2 ) 0.12 , R 1 is a methyl group (80 mole %), a phenyl group (20 mole %), R 2 is a hydrogen atom (10 mole %), a methyl group (90 mole %), has a weight average molecular weight of 3500, a softening point of 77°C, and is a solid at 25°C

[0108] Silicone Resin (A-9): A silicone resin represented by (R 1 SiO 3 / 2 ) 0.80 (R 1 2SiO 2 / 2 ) 0.20 (R 2 O 1 / 2 ) 0.21 , R 1 is a methyl group (100 mole %), R 2 is a hydrogen atom (60 mole %), a methyl group (40 mole %), has a weight average molecular weight of 3000, a softening point of 70°C, and is a solid at 25°C

[0109] Silicone Resin (A-10): A silicone resin represented by (R 1 SiO 3 / 2 ) 0.60 (R 1 2SiO 2 / 2 ) 0.40 (R 2 O 1 / 2 ) 0.21 , R 1 is a methyl group (100 mole %), R 2 is a hydrogen atom (60 mole %), a methyl group (40 mole %), has a weight average molecular weight of 3000, a softening point of 60°C, and is a solid at 25°C

[0110] Stearic acid: Industrial stearic acid (manufactured by Showa Denko K.K.)

[0111] Antioxidant: Nocrack 6C (manufactured by Ono Pharmaceutical Co., Ltd.)

[0112] Resin: T-REZ RA-100 (manufactured by ENEOS Corporation)

[0113] Wax: Ozocerite 355 (manufactured by Nippon Seiro Co., Ltd.)

[0114] Zinc oxide: Zinc oxide No. 3 (manufactured by Mitsui Mining Co., Ltd.)

[0115] Vulcanization accelerator (a): Noccelar DM-P (manufactured by Ono Pharmaceutical Co., Ltd.)

[0116] Vulcanization accelerator (b): Noccelar CZ-G (manufactured by Ono Pharmaceutical Co., Ltd.)

[0117] Sulfur: 5% oil-treated sulfur (manufactured by Seiko Chemical Co., Ltd.)

[0118] For the rubber compositions obtained in the above Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-5, unvulcanized properties and vulcanized properties were measured by the following methods. The results are shown in Table 1. Further, regarding the vulcanized properties, the obtained rubber compositions were press-molded (145°C, 30 minutes) to produce vulcanized rubber sheets.

[0119] [Unvulcanized properties]

[0120] (1) Mooney viscosity

[0121] The Mooney viscosity was measured in accordance with JIS K 6300-1:2013, at a remaining heat of 1 minute, a measurement of 4 minutes, a temperature of 130°C, and the comparative example 1-1 was set to 100, expressed by an index. The smaller the index value, the lower the Mooney viscosity, and the more excellent the processability.

[0122] [Vulcanized properties]

[0123] (2) Hardness

[0124] The hardness was measured in accordance with JIS K 6253-3:2012, and the hardness of the durometer (type A) was measured, and the comparative example 1-1 was set to 100, expressed by an index. The larger the index value, the higher the hardness, and the more excellent.

[0125] (3) Tensile properties

[0126] Test pieces in the shape of JIS No. 3 dumbbell were punched out, and a tensile test was performed at a tensile speed of 500 mm / min in accordance with JIS K6251, and the modulus at 300% (M300) was measured at room temperature. 300[MPa]. Comparative Example 1-1 was set to 100, and the obtained results were expressed by an index. The larger the index value, the higher the modulus, and the more excellent the tensile properties.

[0127] (4) Dynamic viscoelasticity (temperature dispersion)

[0128] Using a viscoelasticity measuring device (manufactured by Metravib), the measurement was performed under the conditions of dynamic deformation of 1% in stretching, and a frequency of 55 Hz. Further, a test piece was used of a sheet having a thickness of 0.2 cm and a width of 0.5 cm, the distance between the grips was set to 2 cm, and the initial load was set to 1 N. Comparative Example 1-1 was set to 100, and the value of tan δ (60°C) was expressed by an index. The smaller the value of tan δ (60°C), the better the rolling resistance.

[0129] (5) Abrasion resistance

[0130] Using an FPS tester (manufactured by Shintech Co., Ltd.), the test was performed under the conditions of a sample speed of 200 m / min, a load of 20 N, a road surface temperature of 30°C, a slip ratio of 5%, and a slip ratio of 20%. Comparative Example 1-1 was set to 100, and the obtained results were expressed by an index. The larger the index value, the smaller the abrasion amount, and the more excellent the abrasion resistance.

[0131] (6) Durability (breaking time)

[0132] Using a flexometer (manufactured by Shintech Co., Ltd.), the test was performed under the conditions of a static load of 60 N, a dynamic displacement of 5.5 mm, a frequency of 45 Hz, and a tank temperature of 100°C. Comparative Example 1-1 was set to 100, and the time until the rubber test piece was broken was expressed by an index. The larger the index value, the longer the time until the breaking, and the higher the durability.

[0133]

[0134] As shown in Table 1, it was found that the vulcanizate of the rubber composition obtained in Examples 1-1 to 1-6 had improved hardness, tensile properties, and durability while maintaining the abrasion resistance, as compared with the vulcanizate of the rubber composition obtained in Comparative Examples 1-1 to 1-5.

[0135] [Examples 2-1 to 2-6, Comparative Examples 2-1 to 2-5]

[0136] Using a 4L banbury mixer (MIXTRON, manufactured by Kobe Steel, Ltd.), the SBR and BR described in Table 2 were kneaded for 30 seconds.

[0137] Next, the oil components, carbon black, silica, thioether silane, silicone resin, stearic acid, antioxidant, and wax listed in Table 2 were added, and the internal temperature was raised to 150°C. After maintaining the temperature at 150°C for 2 minutes, the mixture was discharged. Then, it was stretched using rollers. The resulting rubber was then mixed again using a mixer (MIXTRON, Kobe Steel Corporation) until the internal temperature reached 140°C. After discharge, it was stretched using rollers.

[0138] Zinc oxide, vulcanization accelerator and sulfur as listed in Table 2 were added to the mixture, and it was then mixed to obtain a rubber composition.

[0139] SBR: SLR-4602 (manufactured by Toryon)

[0140] BR: BR-01 (manufactured by JSR Corporation)

[0141] Oil: AC-12 (manufactured by Idemitsu Kosan Co., Ltd.)

[0142] Carbon black: Seast 3 (manufactured by Tokai Carbon Co., Ltd.)

[0143] Silicon dioxide: Nipsil AQ (manufactured by Tosoh Silicon Dioxide Co., Ltd.)

[0144] Thioether-based silanes: KBE-846 (manufactured by Shin-Etsu Chemical Co., Ltd., bis(triethoxysilylpropyl)tetrasulfide)

[0145] Organosilicon resin (A-1): composed of (R) 1 SiO 3 / 2 ) 1.00 (R) 2 O 1 / 2 ) 0.21 Representation, R 1 Methyl (100 mol%), R 2 An organosilicon resin with hydrogen atoms (60 mol%), methyl groups (40 mol%), a weight-average molecular weight of 3000, a softening point of 75°C, and solidity at 25°C.

[0146] Organosilicon resin (A-2): composed of (R) 1 SiO 3 / 2 ) 1.00 (R) 2 O 1 / 2 ) 0.12 Representation, R 1 Methyl (80 mol%), phenyl (20 mol%), R 2 An organosilicon resin with hydrogen atoms (60 mol%), methyl groups (40 mol%), a weight-average molecular weight of 3500, a softening point of 77°C, and solidity at 25°C.

[0147] Organosilicon resin (A-3): composed of (R)1 SiO 3 / 2 ) 1.00 (R 2 O 1 / 2 ) 0.12 denotes, R 1 is a methyl group (80 mole %), a n-propyl group (20 mole %), R 2 is a hydrogen atom (60 mole %), a methyl group (40 mole %), has a weight average molecular weight of 3500, a softening point of 77°C, and is a solid at 25°C

[0148] Silicone resin (A-4): obtained from (R 1 SiO 3 / 2 ) 1.00 (R 2 O 1 / 2 ) 0.12 denotes, R 1 is a methyl group (60 mole %), a phenyl group (40 mole %), R 2 is a hydrogen atom (60 mole %), a methyl group (40 mole %), has a weight average molecular weight of 3700, a softening point of 79°C, and is a solid at 25°C

[0149] Silicone resin (A-5): obtained from (R 1 SiO 3 / 2 ) 1.00 (R 2 O 1 / 2 ) 0.12 denotes, R 1 is a methyl group (40 mole %), a phenyl group (60 mole %), R 2 is a hydrogen atom (60 mole %), a methyl group (40 mole %), has a weight average molecular weight of 3700, a softening point of 79°C, and is a solid at 25°C

[0150] Silicone resin (A-6): obtained from (R 1 SiO 3 / 2 ) 1.00 (R 2 O 1 / 2 ) 0.61 denotes, R 1 is a phenyl group (70 mole %) and a n-propyl group (30 mole %), R 2 is a hydrogen atom (60 mole %), a methyl group (40 mole %), has a weight average molecular weight of 4500, a softening point of 75°C, and is a solid at 25°C

[0151] Silicone resin (A-7): obtained from (R 1 SiO 3 / 2 ) 1.00 (R 2 O 1 / 2 )0.12 represents a methyl group (100 mole %), R 1 represents a methyl group (100 mole %), R 2 represents a hydrogen atom (60 mole %), a methyl group (40 mole %), has a weight average molecular weight of 3000, a softening point of 70°C, and is a solid at 25°C

[0152] Silicone Resin (A-8): obtained from (R 1 SiO 3 / 2 ) 1.00 (R 2 2SiO 1 / 2 ) 0.12 represents a methyl group (100 mole %), R 1 represents a methyl group (100 mole %), R 2 represents a hydrogen atom (60 mole %), a methyl group (40 mole %), has a weight average molecular weight of 3000, a softening point of 70°C, and is a solid at 25°C

[0153] Silicone Resin (A-9): obtained from (R 1 SiO 3 / 2 ) 0.80 (R 1 2SiO 2 / 2 ) 0.20 (R 2 O 1 / 2 ) 0.21 represents a methyl group (100 mole %), R 1 represents a methyl group (100 mole %), R 2 represents a hydrogen atom (60 mole %), a methyl group (40 mole %), has a weight average molecular weight of 3000, a softening point of 70°C, and is a solid at 25°C

[0154] Silicone Resin (A-10): obtained from (R 1 SiO 3 / 2 ) 0.60 (R 1 2SiO 2 / 2 ) 0.40 (R 2 O 1 / 2 ) 0.21 represents a methyl group (100 mole %), R 1 represents a methyl group (100 mole %), R 2 represents a hydrogen atom (60 mole %), a methyl group (40 mole %), has a weight average molecular weight of 3000, a softening point of 70°C, and is a solid at 25°C

[0155] Stearic Acid: Industrial stearic acid (manufactured by Showa Denko K.K.)

[0156] Antioxidant: Norac 6C (manufactured by Ono Pharmaceutical Co., Ltd.)

[0157] Wax: Ozocerite 0355 (manufactured by Nippon Seiro Co., Ltd.)

[0158] Zinc oxide: Zinc oxide No. 3 (manufactured by Sumitomo Metal Mining Co., Ltd.)

[0159] Vulcanization accelerator (a): Noccelar D (manufactured by Ono Pharmaceutical Co., Ltd.)

[0160] Vulcanization accelerator (b): Noccelar DM-P (manufactured by Ono Pharmaceutical Co., Ltd.)

[0161] Vulcanization accelerator (c): Noccelar CZ-G (manufactured by Ono Pharmaceutical Co., Ltd.)

[0162] Sulfur: 5% oil-treated sulfur (manufactured by Seiko Chemical Co., Ltd.)

[0163] For the rubber compositions obtained in Examples 2-1 to 2-6 and Comparative Examples 2-1 to 2-5 described above, unvulcanized properties and vulcanized properties were measured by the following methods. The results are shown in Table 2. Further, regarding the vulcanized properties, the obtained rubber compositions were press-molded (160°C, 10 to 40 minutes) to produce vulcanized rubber sheets (2 mm thick).

[0164] [Unvulcanized properties]

[0165] (1) Mooney viscosity

[0166] The Mooney viscosity was measured in accordance with JIS K 6300-1:2013, at a residual heat of 1 minute, a measurement of 4 minutes, and a temperature of 130°C, and Comparative Example 2-1 was set to 100, expressed by an index. The smaller the index value, the lower the Mooney viscosity, and the more excellent the processability.

[0167] (2) Vulcanization characteristics (T90)

[0168] The vulcanization speed at 160°C was measured using a rotorless rheometer, the minimum torque ML and the maximum torque MH were obtained from the vulcanization curve, and T90 (time (minutes) until the 90% torque value of the maximum torque value) was obtained. Comparative Example 2-1 was set to 100, expressed by an index. The smaller the index value, the faster the vulcanization speed, and the more excellent the productivity.

[0169] [Vulcanized properties]

[0170] (3) Hardness

[0171] The hardness was measured in accordance with JIS K 6253-3:2012, the hardness of a durometer (type A), and Comparative Example 2-1 was set to 100, expressed by an index. The larger the index value, the higher the hardness, and the more excellent.

[0172] (4) Tensile characteristics

[0173] The dumbbell-shaped test piece was punched out, and a tensile test was performed at a tensile speed of 500 mm / min according to JIS K6251 to measure the 300% modulus (M) at room temperature. 300 The comparative example 2-1 was set to 100, and the obtained results were expressed by an index. The larger the index value, the higher the modulus, and the more excellent the tensile properties.

[0174] (5) Dynamic viscoelasticity (temperature dispersion)

[0175] The viscoelasticity measuring device (manufactured by Metravib) was used to measure at a dynamic deformation of 1% in tension, a frequency of 55 Hz. Further, the test piece used was a sheet having a thickness of 0.2 cm and a width of 0.5 cm, the distance between the grips was set to 2 cm, and the initial load was set to 1 N.

[0176] The comparative example 2-1 was set to 100, and the values of tan δ (0°C) and tan δ (60°C) were expressed by an index. In terms of the value of tan δ (0°C), the larger the index value, the better the wet grip performance. In terms of the value of tan δ (60°C), the smaller the index value, the better the rolling resistance.

[0177] (6) Abrasion resistance

[0178] The FPS tester (manufactured by Shintech Co., Ltd.) was used to perform a test under the conditions of a sample speed of 200 m / min, a load of 20 N, a road surface temperature of 30°C, a slip ratio of 5%, and a slip ratio of 20%. The comparative example 2-1 was set to 100, and the obtained results were expressed by an index. The larger the index value, the smaller the amount of abrasion, and the more excellent the abrasion resistance.

[0179] [Unvulcanized properties]

[0180] Mooney viscosity

[0181] The Mooney viscosity was measured according to JIS K 6300-1:2013 at a residual heat of 1 minute, a measurement of 4 minutes, and a temperature of 130°C, the comparative example 2-1 was set to 100, and an index was expressed. The smaller the index value, the lower the Mooney viscosity, and the more excellent the processability.

[0182] [Vulcanized properties]

[0183] Hardness

[0184] The hardness was measured according to JIS K 6253-3:2012, the hardness of the durometer (type A), the comparative example 2-1 was set to 100, and an index was expressed. The larger the index value, the higher the hardness, and the more excellent.

[0185] (3) Tensile properties

[0186] A dumbbell-shaped test piece was punched out, and a tensile test was performed at a tensile speed of 500 mm / min according to JIS K6251, and the modulus at 100% (M) [MPa] was measured at room temperature. Comparative Example 2-1 was set to 100, and the obtained results were expressed by an index. The larger the index value, the higher the modulus, and the more excellent the tensile properties. 300 )[MPa] was measured at room temperature. Comparative Example 2-1 was set to 100, and the obtained results were expressed by an index. The larger the index value, the higher the modulus, and the more excellent the tensile properties.

[0187] (4) Dynamic viscoelasticity (temperature dispersion)

[0188] Using a viscoelasticity measuring device (manufactured by Metravib), the measurement was performed under conditions of a dynamic deformation of 1% at the time of stretching, and a frequency of 55 Hz. Further, a test piece was a sheet having a thickness of 0.2 cm and a width of 0.5 cm, and the distance between the grips was set to 2 cm, and the initial load was set to 1 N.

[0189] Comparative Example 2-1 was set to 100, and the values of tan δ (0°C) and tan δ (60°C) were expressed by an index. The larger the index value of tan δ (0°C), the better the wet grip performance. The smaller the index value of tan δ (60°C), the better the rolling resistance.

[0190] Wear resistance

[0191] Using an FPS tester (manufactured by Shintech Co., Ltd.), the test was performed under conditions of a sample speed of 200 m / min, a load of 20 N, a road surface temperature of 30°C, a slip ratio of 5%, and a slip ratio of 20%. Comparative Example 2-1 was set to 100, and the obtained results were expressed by an index. The larger the index value, the smaller the wear amount, and the more excellent the wear resistance.

[0192] (6) Durability (creep rate)

[0193] Using a flexometer (manufactured by Shintech Co., Ltd.), the test was performed under conditions of a static load of 60 N, a dynamic displacement of 5.5 mm, a frequency of 45 Hz, and a tank temperature of 100°C. The creep rate (%) after 15 minutes was measured. Comparative Example 2-1 was set to 100, and the obtained results were expressed by an index. The smaller the index value, the higher the durability.

[0194]

[0195] As shown in Table 2, it was found that the vulcanizate of the rubber composition obtained in Examples 2-1 to 2-6 had a significantly improved hardness, tensile properties, and durability while maintaining the wear resistance, as compared with the vulcanizate of the rubber composition obtained in Comparative Examples 2-1 to 2-5.

Claims

1. A diene-based rubber compounding agent comprising (A) an organosilicon resin represented by the following formula (1), (SiO 4 / 2 ) a (R 1 SiO 3 / 2 ) b (R 1 2SiO 2 / 2 ) c (R 1 3SiO 1 / 2 ) d (R 2 O 1 / 2 ) e (1) In the formula, R 1 Each independently represents a hydrogen atom, or an alkyl, aralkyl, or aryl group having 1 to 8 carbon atoms that can be substituted with a halogen atom; R 1 At least 50 mol% of it is methyl, R 2 Represents a hydrogen atom, methyl, ethyl, n-propyl, isopropyl, or acetyl group, R 2 At least 20 mol% of the atoms are hydrogen atoms, a, b, c, and d are numbers that satisfy 0 ≤ a < 1, 0 < b ≤ 1, 0 ≤ c < 1, 0 ≤ d < 1, and a + b + c + d = 1, and e is a number that satisfies 0 < e ≤ 2.

2. The diene-based rubber compounding agent according to claim 1, wherein, The b is a number that satisfies 0.4 ≤ b ≤ 1.

3. The diene-based rubber compounding agent according to claim 2, wherein, The value of b is 1.

4. The diene-based rubber compounding agent according to claim 1, wherein, The silicone resin is solid at 25°C.

5. The diene rubber compounding agent according to any one of claims 1 to 4, further comprising (B) an organosilicon compound having one or more selected from polysulfide groups, thioester groups and mercapto groups, and an alkoxysilyl group.

6. A rubber composition comprising: (A) The silicone resin represented by the following formula (1), (SiO 4 / 2 ) a (R 1 SiO 3 / 2 ) b (R 1 2SiO 2 / 2 ) c (R 1 3SiO 1 / 2 ) d (R 2 O 1 / 2 ) e (1) In the formula, R 1 Each independently represents a hydrogen atom, or an alkyl, aralkyl, or aryl group having 1 to 8 carbon atoms that can be substituted with a halogen atom; R 1 At least 50 mol% of it is methyl, R 2 Represents a hydrogen atom, methyl, ethyl, n-propyl, isopropyl, or acetyl group, R 2 In the given information, at least 20 mol% consists of hydrogen atoms, a, b, c, and d are numbers that satisfy 0 ≤ a < 1, 0 < b ≤ 1, 0 ≤ c < 1, 0 ≤ d < 1, and a + b + c + d = 1, and e is a number that satisfies 0 < e ≤ 2. (B) An organosilicon compound having one or more of the following groups: polysulfide, thioester, and mercapto, and an alkoxysilyl group. (C) Diene-based rubbers, and (D) Inorganic fillers.

7. A tire formed from the rubber composition according to claim 6.

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