JP2002327093A - Rubber composition and tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition enabling to give a tire having improved elastic modulus at low strain and enhanced productivity, and to provide a tire using the composition. SOLUTION: This rubber composition comprises (A) a natural rubber and/or a synthetic rubber and (B) a sulfurized fatty acid derivative expressed by general formula (I): R<1> -(S)x -R<2> , where R<1> represents a hydrocarbon group having at least a carboxy group or a salt thereof; R<2> represents a hydrocarbon group optionally having a carboxy group or a salt thereof; x is an integer of 1 to 8; and in case that a plurality of S (x>=2) are included, each S may be bonded directly or bonded through a bivalent hydrocarbon group or an oxyalkylene group which may have a substituent. This tire uses the rubber composition as the rubber component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a rubber composition and a tire using the same. More specifically, the present invention relates to a rubber composition containing a sulfided fatty acid derivative, which can provide a tire with improved productivity and steering performance, and a pneumatic tire using the rubber composition as a rubber member. .

[0002]

2. Description of the Related Art In recent years, in the tire industry, higher driving performance has been demanded as the performance of automobiles has become higher. It has been found that it is effective to have a high elastic modulus mainly in a low distortion region as one method of improving the steering performance. Therefore, it has been studied to mix various kinds of fillers, mainly silica, and to mix resins. However, there is a problem that the workability is inevitably deteriorated by blending them. Therefore, in order to solve such a problem, it has been attempted to use a workability improver such as a fatty acid or a fatty acid salt in combination. However, by using these workability improvers, workability is improved, but at the same time, the elastic modulus in the low strain region tends to decrease.

[0003]

SUMMARY OF THE INVENTION The present invention provides a rubber composition capable of providing a tire having improved productivity and high steering performance under such circumstances, and a tire using the same. The purpose is to do so.

[0004]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that a rubber composition containing a sulfurized fatty acid derivative having a specific structure can achieve the object. And the sulfurized fatty acid derivative is
Although there are known examples as extreme pressure agents and lubricants, there is no known example applied to a rubber composition, and there is 3-mercaptopropionic acid as a compound relatively similar to the sulfurized fatty acid derivative. It has been found that when this compound is compounded in a rubber composition, the scorch time is shortened, but the effect of improving workability is hardly recognized. The present invention has been completed based on such findings. That is, the present invention provides (A) a rubber component containing at least one selected from natural rubber and synthetic rubber;
(B) Formula (I) R ^1- (S) _x -R ² (I) wherein R ¹ is a carboxyl group or a hydrocarbon group having at least one salt thereof, and R ² is a carboxyl group Or a hydrocarbon group optionally having a salt thereof, x is 1 to 8
And when S is plural (x ≧ 2), S may be directly bonded to each other, and may be bonded via a divalent hydrocarbon group having or not having a substituent or an oxyalkylene group. May be. The present invention provides a rubber composition characterized by containing a sulfurized fatty acid derivative represented by the following formula:
The present invention also provides a tire using the rubber composition as a rubber member.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As the rubber component (A) in the rubber composition of the present invention, a rubber component containing at least one selected from natural rubber and synthetic rubber is used. As the synthetic rubber used in the present invention, a diene rubber is preferable. For example, cis-1,4-polyisoprene, styrene / butadiene copolymer, low cis-1,4-polystyrene is used.
Examples thereof include polybutadiene, high cis-1,4-polybutadiene, ethylene-propylene-diene copolymer, chlorobrene rubber, halogenated butyl rubber, and acrylonitrile-butadiene rubber. In the present invention, as the rubber component, natural rubber and synthetic rubber can be used alone or as a blend. Preferred rubbers include natural rubber, cis-1,4-polyisoprene, styrene / butadiene copolymer, and polybutadiene.

In the present invention, the rubber component (A) preferably contains at least 50% by weight of natural rubber or at least 50% by weight of styrene-butadiene copolymer (SBR). Thereby, the following (B) will be described.
The improvement effect of the component sulfurized fatty acid derivative is effectively exhibited. In the rubber composition of the present invention, as the component (B), a sulfurized fatty acid derivative represented by the general formula (I) R ^1- (S) _x -R ² (I) is used. In the general formula (I), R ¹ represents a hydrocarbon group having at least one carboxyl group or a salt thereof, and R ² represents a hydrocarbon group optionally having a carboxyl group or a salt thereof. Here, as the salt of the carboxyl group, an alkali metal salt, an alkaline earth metal salt, an ammonium salt,
Zn salt, Al salt, Sn salt, Sb salt and the like can be mentioned. The hydrocarbon group is preferably one having 6 to 20 carbon atoms, for example, a linear or branched alkyl group or alkenyl group having 6 to 20 carbon atoms, a cycloalkyl group or cycloalkenyl having 6 to 20 carbon atoms. Preferred examples include a group, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms. These hydrocarbon groups may have an appropriate substituent other than the carboxyl group or a salt thereof.

When the number of carbon atoms of the hydrocarbon group is 5 or less, it is difficult to obtain a sufficient effect of improving workability. On the other hand, when the number of carbon atoms is 21 or more, the effect of improving the elastic modulus tends to be small. x represents an integer of 1 to 8, and when S is plural (x ≧ 2), each S may be directly bonded to each other, or may be a divalent hydrocarbon group having or not having a substituent or an oxy group. They may be bonded via an alkylene group. Here, examples of the divalent hydrocarbon group include an alkylene group having 1 to 10 carbon atoms, an alkenylene group having 2 to 10 carbon atoms, and a 5 to 10 carbon atoms.
A cycloalkylene or cycloalkenylene group, an arylene group having 6 to 10 carbon atoms, an aralkylene group having 7 to 10 carbon atoms, and the like. Examples of the substituent include a halogen atom or a halogen atom, O, S, N
And various groups containing a hetero atom. As the sulfurated fatty acid derivative of the component (B), one kind may be used alone, or two or more kinds may be used in combination. As the sulfurized fatty acid derivative, for example, a commercially available product such as "GS550" (trade name, manufactured by Dainippon Ink and Chemicals, Inc.), which is sulfurized distearic acid, can be used. It is considered that the sulfided fatty acid derivative acts as a lubricant by reacting with zinc white in the rubber composition, like a general fatty acid, so that it is thought that the effect of improving workability is exhibited. In addition, the sulfur-bonded portion is cleaved during the vulcanization reaction to form a polymer, and this polymer is a sulfurized fatty acid-zinc white-
It is considered that the elastic modulus is improved because the sulfided fatty acids are linked by crosslinking.

In the rubber composition of the present invention, the sulfurated fatty acid derivative of the component (B) is added in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the rubber component of the component (A). Is preferred. If the compounding amount is less than 0.1 part by weight, the compounding effect may not be sufficiently exerted. On the other hand, if the compounding amount is more than 10 parts by weight, the fracture resistance of the rubber may be reduced. A more preferred amount is in the range of 0.5 to 5 parts by weight. In the rubber composition of the present invention,
As the component (C), general formula (II)

[0009]

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(Wherein, R ³ and R ⁴ each represent a hydrogen atom or a methyl group, which may be the same or different, and y represents an integer of 0 to 5). A polymaleimide derivative can be blended. By blending this polymaleimide derivative, the elastic modulus can be improved while maintaining good workability. As the polymaleimide derivative, one type may be used alone, or two or more types may be used in combination. Further, 0.1 to 100 parts by weight of the rubber component (A) is used.
It is preferable to mix in a range of 10 parts by weight. If the amount is less than 0.1 part by weight, the effect of the compounding may not be sufficiently exhibited. On the other hand, if the amount exceeds 10 parts by weight, the fracture resistance and workability may be reduced. The more preferable blending amount of the polymaleimide derivative is in the range of 0.5 to 5 parts by weight. The polymaleimide derivative has a general formula (III)

[0011]

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Wherein R ³ , R ⁴ and y are as defined above, and at least one selected from maleic anhydride, citraconic anhydride and dimethylmaleic anhydride. It can be produced by reacting. In the rubber composition of the present invention, a reinforcing filler can be blended as the component (D). Examples of the reinforcing filler include at least one selected from carbon black, silica, calcium carbonate, titanium oxide, alumina, and the like. As the reinforcing filler, at least 40% by weight of carbon black and / or silica, especially at least 2% of silica.
The one containing 0% by weight is preferable because the improvement effect by the sulfurized fatty acid derivative of the component (B) can be effectively exhibited by blending it. It is advantageous that the reinforcing filler of the component (D) is blended in an amount of 20 parts by weight or more, preferably 20 to 150 parts by weight, based on 100 parts by weight of the rubber component of the component (A). If the amount is less than 20 parts by weight, the fracture properties and wear resistance of the vulcanizate may be insufficient, while if it exceeds 150 parts by weight, physical properties and the like may be reduced. A more preferred amount of the reinforcing filler is in the range of 25 to 80 parts by weight. Examples of the carbon black used as the reinforcing filler include HAF, ISAF, and SAF.

In the rubber composition of the present invention, a novolak-type phenol resin and / or a modified polyolefin resin are used as the reinforcing resin of the component (E) for the purpose of increasing the hardness, and 100 parts by weight of the rubber component of the component (A). Against
It can be blended in the range of 0.5 to 10 parts by weight. Novolak type phenolic resins include novolak type unmodified phenolic resins and animals and plants composed of rosin oil, tall oil, cashew nut oil, linseed oil and the like, unsaturated oils composed of linoleic oil, oleic acid oil, linolenic oil, etc. Novolak-type modified phenol resin modified with any of the following aromatic hydrocarbon resins. When this novolak type phenol resin is used in combination, it is preferable to further use a methylene donor as a curing agent. Hexamethylenetetramine and methylolated melamine derivatives can be used as methylene donors. For example, hexamethylolmelamine, hexamethoxymethylmelamine, hexaethoxymethylmelamine, hexakis- (methoxymethyl) melamine, N, N ',
N "-trimethyl-N, N ', N" -trimethylolmelamine, N, N', N "-trimethylolmelamine, N
-Methylolmelamine, N, N'-di (methoxymethyl) melamine, N, N ', N "-tributyl-N,
N ', N "-trimethylolmelamine and the like can be exemplified.
Further, the modified polyolefin resin contains one or more functional groups, and the functional group is preferably derived from maleic anhydride, acrylic acid, epoxides and the like. For example, "POLYBOND 3009" or "3109" manufactured by Uniroyal Chemical Company
Etc. can be used.

When the rubber composition of the present invention is used as a tire case rubber for wire coating or bead coating, the rubber composition preferably contains an adhesion improver as a component (F). Examples of the used adhesion improver include metal salts of organic acids, metal salts of boric acid, triazine compounds,
Sodium alkylenedithiosulfate is preferred. For the purpose of this compounding, the compounding amount is 0.1 part by weight with respect to 100 parts by weight of the rubber component.
3 to 10 parts by weight are preferred. As the metal of the organic acid metal salt, Co, Ni, etc. can be used, and as the organic acid, stearic acid, palmitic acid, necadenoic acid, versatic acid,
C6-C30 aliphatic or alicyclic carboxylic acids such as oleic acid, linoleic acid, linoleic acid, ricinoleic acid, naphthenic acid, and abietic acid and rosin acid can be used. The metal borate is represented by the general formula (IV)

[0015]

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(Wherein M ¹ , M ² and M ³ each independently represent Co or Ni, and X, Y and Z each independently represent hydrogen of a carboxyl group in a monocarboxylic acid having 7 to 11 carbon atoms) And a residue excluding an atom.). As such a boric acid metal salt, for example, as a commercially available product, "Monobo" manufactured by Rhodia Co., Ltd., which is cobalt (II) trineodecanoate borate.
nd C22.5 ". As the triazine compound, for example, triazine trithiol
Mono-alkali metal salts can be mentioned. As the sodium alkylenedithiosulfate, for example, as a commercial product, sodium 1,6-hexamethylenedithiosulfate.
Flexura's “Durallink” dihydrate
HTS "and the like. In the rubber composition of the present invention, in addition to the components (A) to (F), a silane coupling agent, a vulcanizing agent, a vulcanization accelerator, a vulcanizing accelerator, a A sulfur promoting accelerator, an antioxidant, an antiozonant, an antioxidant, a process oil, zinc white (ZnO), stearic acid, and the like can be added.

Examples of the vulcanizing agent that can be used in the present invention include sulfur and the like.
The sulfur content is usually 0.1 to 10 parts by weight based on 00 parts by weight. If the amount is less than 0.1 part by weight, the fracture characteristics and abrasion resistance of the vulcanized rubber decrease, and if it exceeds 10 parts by weight, the rubber elasticity tends to be lost. From the same viewpoint, the amount is preferably 0.5 to 6.0 parts by weight. Examples of the process oil that can be used in the present invention include, for example, paraffinic, naphthenic, and aromatic types. For applications where emphasis is placed on fracture characteristics and abrasion resistance, an aromatic type is used. For applications where low-temperature characteristics are important, naphthenic or paraffinic materials are used, respectively. The amount of the rubber component is preferably 100 parts by weight or less based on 100 parts by weight of the rubber component, because if it exceeds 100 parts by weight, the fracture characteristics and low heat build-up of the vulcanized rubber are significantly deteriorated. The vulcanization accelerator that can be used in the present invention is not particularly limited, but is preferably MBT (2-mercaptobenzothiazole), DM (dibenzothiazyl disulfide), CBS (N-cyclohexyl-2-benzo). Thiazylsulfenamide), TBBS (Nt-butyl-2)
-Benzothiazylsulfenamide), TBSI (N-
benzothiazole-based vulcanization accelerators such as t-butyl-2-benzothiazylsulfenimide), guanidine-based vulcanization accelerators such as DPG (diphenylguanidine), tetradodecylthiuram disulfide, tetraoctylthiuram disulfide, tetra Thiuram-based vulcanization accelerators such as benzylthiuram disulfide, and vulcanization accelerators such as zinc dialkyldithiophosphate can be exemplified, and the amount of use is preferably 0.1 to 5 parts by weight per 100 parts by weight of the rubber component, More preferably, it is 0.2 to 3 parts by weight. The present invention is extremely effective for rubber compositions and tires containing a benzothiazole vulcanization accelerator. In addition, the addition of a thiuram-based accelerator also contributes to an increase in the vulcanization rate. Among them, a rubber composition using tetradodecylthiuram disulfide, tetraoctylthiuram disulfide, and tetrabenzylthiuram disulfide in combination with a benzothiazole accelerator is extremely effective.

The rubber composition of the present invention comprises the above (A)
(F) It is obtained by kneading the components and various additional components used as necessary using a kneading machine such as a roll or an internal mixer.
Tire tread, under tread, sidewall,
The rubber parts such as bead part, carcass, belt and other coating rubber are used for tires, anti-vibration rubber, belt,
It can also be suitably used for applications such as hoses and other industrial products. The present invention also provides a tire using the rubber composition as a rubber member, particularly a pneumatic tire.

[0019]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Examples 1 to 18 and Comparative Examples 1 to 6 The types and amounts of the components shown in Table 1 (formulation for tire tread) and Table 2 (formulation for coating tire cord) were 500
The mixture was kneaded and mixed using a milliliter Labo Plastomill and a 7.6 cm roll to prepare an unvulcanized rubber composition. Each rubber composition was subjected to a Mooney viscosity test by the following method (1) and a tensile test and a dynamic viscoelasticity test after vulcanization by the following methods (2) and (3), respectively. The results are shown in Tables 1 and 2.

(1) Mooney Viscosity Test A Mooney viscosity test was conducted in accordance with JIS K6300-1994, and Mooney viscosity and Mooney scorch time were measured. Each data shows that Comparative Examples 1 to 6 are 10
Expressed as an index as 0. (2) Tensile test At 145 ° C., the increase in torque due to the vulcanization
0% to reach pressure between 1.5 times corresponding to vulcanization time T ₉₀ after curing (using No. 3 specimen) subjected to a tensile test according to JIS K6301-1995, 300% elongation at the elastic modulus (M ₃₀₀ ) was measured. Each data is represented by an index with Comparative Examples 1 to 6 being 100.

(3) Dynamic viscoelasticity test Using a spectrometer (dynamic viscoelasticity measuring tester) manufactured by Toyo Seiki Co., Ltd., a frequency of 52 Hz and a measurement temperature of 30 ° C.
E ′ (dynamic storage modulus) and tan δ (loss coefficient) were measured at a strain of 1%. Each data is 1 for each of Comparative Examples 1 to 6.
It is represented by an index as 00. Further, Examples 5, 6, 8, and 9
185 / 70R14 size tread (single-layer structure) using the rubber compositions of Comparative Examples 2 and 3 as tread rubber
The pneumatic tires were prototyped, and the performance of each tire was evaluated in terms of maneuverability by actual vehicle running according to the following method (4). The results are shown in Table 1.

(4) Drivability On a test course on a dry asphalt road surface, a real vehicle was run using an FF4 door sedan fitted with each new tire, and the driving performance, braking performance, steering wheel responsiveness, and controllability at the time of driving were controlled. A test driver comprehensively evaluated the tires of Comparative Examples 2 and 3 as control tires. +1: Protest driver feels slightly better than control tires. +2: Protest driver feels better than control tires. +3: Skilled driver compared to control tires. +4: When the driver feels good enough to understand the general driver compared to the control tire

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

[Note] SBR 1500: Styrene-butadiene copolymer, JS
Carbon black manufactured by R Co., Ltd .: "Seast 3" manufactured by Tokai Carbon Co., Ltd.
H "(ISAF) Silica:" Nip Seal AQ "manufactured by Nippon Silica Industry Co., Ltd. Silane coupling agent:" Si69 "manufactured by Degussa Nocrack 6C: N- (1,3-dimethylbutyl)-
N'-phenyl-p-phenylenediamine, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Noxeller D: diphenylguanidine; manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Noxeller NS: Nt-butyl-2-benzothiazyl sulfen Amide, manufactured by Ouchi Shinko Chemical Co., Ltd. Sulfurized fatty acid derivative: "G" manufactured by Dainippon Ink and Chemicals, Inc.
S550 ", sulfurized distearic acid bismaleimide:" BMI-S "manufactured by Mitsui Chemicals, Inc.
N, N '-(4,4'-diphenylmethane) bismaleimide

[0027]

[Table 4]

[0028]

[Table 5]

[0029]

[Table 6]

[Note] Carbon black: “Asahi # 70 (N) manufactured by Asahi Carbon Co., Ltd.
330) "Nocrack 6C: N- (1,3-dimethylbutyl)-
N'-phenyl-p-phenylenediamine, Noxeller NS manufactured by Ouchi Shinko Chemical Co., Ltd. NS: Nt-butyl-2-benzothiazyl sulfenamide, Noxeller DZ: N manufactured by Ouchi Shinko Chemical Co., Ltd. , N'-Dicyclohexyl-2-benzothiazyl sulfenamide, manufactured by Ouchi Shinko Chemical Co., Ltd. Reinforcement resin: "PR5023" manufactured by Sumitomo Durez Co., Ltd.
Novolak type unmodified phenolic resin Curing agent: Hexamethylenetetramine Adhesion improver: "Manobond C22.5" manufactured by Rhodia Sulfurized fatty acid derivative: "G" manufactured by Dainippon Ink and Chemicals, Inc.
S550 ", sulfurized distearic acid bismaleimide:" BMI-S "manufactured by Mitsui Chemicals, Inc.
N, N '-(4,4'-diphenylmethane) bismaleimide

As can be seen from Table 1 (combination for tire tread), when the sulfurized fatty acid derivative is added to Comparative Examples 1, 2, and 3, the Mooney viscosity is reduced, the scorch time is increased, and work stability is improved. The property becomes good. The modulus (M ₃₀₀ ) also increases slightly as the amount of silica added increases, but the dynamic viscoelastic modulus E ′ greatly increases. Further addition of bismaleimide further increases the modulus of elasticity E '. From Table 2, it can be seen that similar results were obtained with the tire cord coating composition. Furthermore, when the rubber composition having the composition shown in Table 1 is used in the tread portion, it can be seen that the steering performance of the example is remarkably improved as compared with that of the comparative example.

[0032]

According to the present invention, it is possible to obtain a rubber composition capable of providing a tire having improved productivity and low strain elastic modulus.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/3415 C08K 5/3415 5/372 5/372 C08L 7/00 C08L 7/00 9/06 9 / 06 // (C08L 21/00 C08L 61:06 61:06) 23:26 (C08L 21/00 23:26) F term (reference) 4J002 AC001 AC011 AC031 AC061 AC071 AC081 AC091 BB151 BB202 BB241 CC032 DA038 DE138 DE148 DE238 DJ018 EG009 EU027 EV019 EV046 EV189 EY019 FD018 FD206 FD207 FD209 GN01

Claims (11)

[Claims] 1. A rubber component containing (A) at least one selected from natural rubber and synthetic rubber, and (B) a general formula (I) R ^1- (S) _x -R ² ... (I) (Wherein, R ¹ is a hydrocarbon group having at least one carboxyl group or a salt thereof, R ² is a hydrocarbon group optionally having a carboxyl group or a salt thereof, and x is 1 to 8
And when S is plural (x ≧ 2), S may be directly bonded to each other, and may be bonded via a divalent hydrocarbon group having or not having a substituent or an oxyalkylene group. May be. A rubber composition comprising the sulfurized fatty acid derivative represented by the formula (1). 2. The rubber composition according to claim 1, wherein R ² in the general formula (I) is a carboxyl group or a hydrocarbon group having at least one salt thereof. 3. The composition of (B) per 100 parts by weight of the component (A)
3. The rubber composition according to claim 1, comprising 0.1 to 10 parts by weight of a component. 4. The rubber component (A) is composed of natural rubber 50.
The rubber composition according to any one of claims 1 to 3, wherein the rubber composition contains not less than% by weight. 5. The rubber composition according to claim 1, wherein the rubber component (A) contains 50% by weight or more of a styrene / butadiene copolymer (SBR). (C) a compound represented by the following general formula (II): (Wherein, R ³ and R ⁴ each represent a hydrogen atom or a methyl group, and they may be the same or different, and y represents an integer of 0 to 5). The rubber composition according to any one of claims 1 to 5, comprising: 7. (C) per 100 parts by weight of component (A)
The rubber composition according to claim 6, comprising 0.1 to 10 parts by weight of a component. 8. The method according to claim 1, further comprising (D) at least 20 parts by weight of a reinforcing filler per 100 parts by weight of the component (A).
8. The rubber composition according to any one of items 1 to 7. 9. The composition according to claim 1, further comprising (E) 0.5 to 10 parts by weight of a novolak-type phenol resin and / or a modified polyolefin resin per 100 parts by weight of the component (A).
8. The rubber composition according to any one of items 1 to 7. 10. An adhesion enhancer selected from the group consisting of (F) a metal salt of an organic acid, a metal salt of boric acid, a triazine compound and sodium alkylenedithiosulfate per 100 parts by weight of the component (A). The rubber composition according to any one of claims 1 to 9, comprising 10 to 10 parts by weight. 11. A tire using the rubber composition according to any one of claims 1 to 10 as a rubber member.