JP2015189970A - rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition having excellent low heat build-up and elasticity and consisting of an organified clay where a specific quaternary organic ammonium ion is introduced in interlayer, carbon black, a silane coupling agent and a dispersant with polybutadiene.SOLUTION: There are provided a hydrocarbon composition containing a vulcanizable rubber (A) and a laminar clay mineral (B) to which quaternary ammonium (RRN(XH)) (B) is introduced, carbon black (C), a silane coupling agent (D) and a dispersant (E), and a hydrocarbon compound where Rand Rrepresent at least one kind of any functional group selected from a group consisting of hydrogen, methyl, ethyl, propyl, butyl or pentyl group, N is a nitrogen element and XH has 20 to 10 carbon atoms in the formula and terminals are hydrogenated.

Description

  The present invention provides a rubber composition comprising an organic clay, a carbon black, a silane coupling agent, and a dispersant obtained by introducing a specific quaternary organic ammonium ion into a polybutadiene having excellent low heat buildup and elastic properties. .

  In general, fillers such as carbon black and silica are blended in view of the effect of reinforcing rubber. In recent years, the use of various fillers has been tried, and the development of rubber compositions that produce derived effects other than the reinforcing effect by blending clay compounds and the like has been made.

In particular, there has been reported an invention in which a compound obtained by organically treating a layered clay mineral, so-called organic clay, is blended in a rubber composition.
By applying such treatment, a run-flat tire and an inner liner for a tire exhibiting excellent gas barrier characteristics are provided (Patent Document 1).
Also disclosed is a method for producing an organized layered clay mineral having improved dispersibility by organizing the layered clay mineral with an organic onium ion in the presence of rubber latex (Patent Document 2).
Further, by treating the clay mineral with an organic compound containing a polymerization residue of an ammonium group, an organized clay mineral with high thermal stability can be produced (Patent Document 3).

There are also examples in which these characteristics are used for tires and the like. For example, a rubber component, an inorganic filler containing silica and montmorillonite, natural rubber, and epoxidized natural rubber are blended to produce a tire having high rigidity, low heat build-up, and excellent workability during preparation (Patent Document 4). ).
However, in order to increase the low exothermic property and other mechanical strength while maintaining the workability, there are many methods by modifying the rubber used as the base material, leading to an increase in manufacturing costs.

JP 2007-112847 A JP 2005-289758 A Japanese Patent Laid-Open No. 2005-076001 Japanese Patent No. 4968732

  The present invention provides a rubber composition excellent in low heat buildup and elastic properties by adding carbon black, a silane coupling agent and a dispersing agent to an organized clay in which a specific quaternary organic ammonium ion is introduced between polybutadienes. Can be provided.

式中Ｒ^１およびＲ^２は水素、メチル、エチル、プロピル、ブチルあるいはペンチル基からなる群から選択される少なくとも一種の官能基のいずれかを示し、Ｎは窒素元素およびＨXは炭素数が２０〜１０であって、末端が水素化された炭化水素化合物。 Vulcanizable rubber (A), layered clay mineral (B) in which quaternary ammonium having the following general formula (1) is inserted, carbon black (C), silane coupling agent (D) and dispersant ( E).

Wherein R ¹ and R ² are any one of at least one functional group selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl or pentyl groups, N is a nitrogen element, and HX is a carbon atom having 20 to 20 carbon atoms. 10. A hydrocarbon compound having a hydrogenated terminal.

The vulcanizable rubber (A) is a polybutadiene having a cis-1,4 structure of 80% or more and a Mooney viscosity (ML _{1 + 4} , 100 ° C.) of 25-80. Relates to the composition.

  The layered clay mineral before the quaternary ammonium of (B) is inserted has a thickness of 3 nm or more.

  The dispersant (E) is ethylene glycol, and relates to the rubber composition described above.

  According to the present invention, the exothermic property of the rubber composition can be further suppressed.

(Vulcanizable rubber)
Examples of vulcanizable rubber include natural rubber (NR), ethylene propylene diene rubber (EPDM), nitrile rubber (NBR), butyl rubber (IIR), chloroprene rubber (CR), polyisoprene, polybutadiene rubber (BR), styrene- Examples thereof include diene rubbers such as butadiene rubber (SBR), butyl rubber, chlorinated butyl rubber, brominated butyl rubber, and acrylonitrile-butadiene rubber. These can be used alone or in a blend of two or more.
Here, the vulcanizable rubber is contained in an amount of 50 phr or more, more preferably 60 phr or more, in 100 phr (parts by weight) of the rubber composition.
Of these, polybutadiene is particularly preferred.
As polybutadiene, polybutadiene polymerized with a cobalt catalyst system is preferable, but polybutadiene based on a neodymium catalyst, a nickel catalyst, and a lithium catalyst may be used.
Further, a high cis-BR having a microstructure with a 1,4-cis bond ratio of 80 mol% or more is preferred, a 1,4-cis bond ratio of 90 mol% or more, particularly preferably 1,4-cis bond. Those having a bond ratio of 95 mol% or more are preferred.
This is because when vulcanized, wear resistance when used as a tire can be improved. Alternatively, vinyl cis-polybutadiene (VCR) containing 1 to 30% by weight of boiling n-hexane insoluble matter (mainly syndiotactic-1,2-polybutadiene) is further enhanced in the reinforcing effect. More preferred.

Moreover, it is preferable that the Mooney viscosity (ML1 ₊ 4,100 degreeC) of polybutadiene is 25-80, 29-69 are more preferable, 30-50 are especially preferable.
Generally, the lower the Mooney viscosity, the better the workability, but the lower the mechanical strength. On the other hand, the higher the Mooney viscosity, the higher the mechanical strength, but the lower the workability.

(Quaternary organic ammonium ion)
As the quaternary organic ammonium ion, those having 20 to 10 carbon atoms as indicated by XH in formula (1) and having two hydrogenated hydrocarbon compounds are preferable. In this case, the two XHs may have the same chemical structural formula or different chemical structural formulas as long as the carbon number is 20 to 10.
R ¹ and R ² are preferably any one of at least one functional group selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl and pentyl groups. In particular, when introduced between layers of a layered clay mineral, hydrogen, methyl and ethyl are more preferable, and a methyl group is most preferable from the viewpoint of the strength of bonding due to strong polarity on the surface inside the layer. R ¹ and R ² may have the same chemical structural formula or different chemical structural formulas.

In the case where R ¹ and R ² have the same chemical structural formula, if XH is also the same chemical structural formula, the three-dimensional structure when introduced between the layers becomes uniform, which is a more preferable form. On the other hand, when R ¹ and R ² have different chemical structural formulas, it is preferable that the intermolecular distance is the same as XH farthest through N as the central element in the case of formula (1). This is because such quaternary organic ammonium ions are introduced between the layers, so that the distance between the layers is kept uniform from the balance of the three-dimensional structure.
Therefore, the best form to be introduced in order to achieve the maximum effect of the present invention is a quaternary organic ammonium ion in which R ¹ and R ² are the same and two XHs have the same target structure. .

  On the other hand, primary, secondary, and tertiary organic ammonium ions can also be used, but since there are only 1 to 3 bonding groups between layers, quaternary organic ammonium ions having four bonding groups. The effect is low compared to.

In particular, in the present invention, the interlayer spacing of the layered clay mineral is kept wider and homogeneous in the stage before polymerization, and when the vulcanizable rubber polymerization stage is reached, each layer of the layered clay mineral collapses with good dispersion. It is important to continue.
Therefore, the interlayer spacing of the layered clay mineral before polymerization is preferably in a layered state with the spacing extended to the maximum.

Specific examples of the quaternary organic ammonium ion having 20 carbon atoms represented by XH in the formula (1) include diicosanyl ammonium ion, diicosanyl dimethyl ammonium ion, diicosanyl diethyl ammonium ion, dii Cosanyldipropylammonium ion, diicosanyldibutylammonium ion, diicosanyldipentylammonium ion, and the like.
The quaternary organic ammonium ions having 19 carbon atoms as represented by XH in formula (1) include dinonadecyl ammonium ion, dinonadecyl dimethyl ammonium ion, dinonadecyl diethyl ammonium ion, dinonadecyl dipropyl ammonium ion. Ions, dinonadecyl dibutylammonium ion, and dinonadecyl dipentylammonium ion.
The quaternary organic ammonium ion having 18 carbon atoms as represented by XH in the formula (1) includes dioctadecyl ammonium ion, dioctadecyl dimethyl ammonium ion, dioctadecyl diethyl ammonium ion, dioctadecyl dipropyl ammonium ion, dioctadecyl. Dibutyl ammonium ion, dioctadecyl dipentyl ammonium ion, dioleyl ammonium ion, dioleyl dimethyl ammonium ion, dioleyl diethyl ammonium ion, dioleyl dipropyl ammonium ion, dioleyl dibutyl ammonium ion, dioleyl dipentyl ammonium ion.
Examples of the quaternary organic ammonium ion having 17 carbon atoms as represented by XH in the formula (1) include diheptadecyl ammonium ion, diheptadecyl dimethyl ammonium ion, diheptadecyl diethyl ammonium ion, and diheptadecyl dipropyl ammonium ion. Ions, diheptadecyldibutylammonium ion, and diheptadecyldipentylammonium ion.
The quaternary organic ammonium ions having 16 carbon atoms as represented by XH in formula (1) include dihexadecyl ammonium ion, dihexadecyl dimethyl ammonium ion, dihexadecyl diethyl ammonium ion, and dihexadecyl dipropyl ammonium ion. Ions, dihexadecyl dibutyl ammonium ion, dihexadecyl dipentyl ammonium ion.
The quaternary organic ammonium ions having 15 carbon atoms as represented by XH in formula (1) include dipentadecyl ammonium ion, dipentadecyl dimethyl ammonium ion, dipentadecyl diethyl ammonium ion, and dipentadecyl dipropyl ammonium ion. Ions, dipentadecyl dibutyl ammonium ion, dipentadecyl dipentyl ammonium ion.
The quaternary organic ammonium ions having 14 carbon atoms as represented by XH in formula (1) include ditetradecyl ammonium ion, ditetradecyl dimethyl ammonium ion, ditetradecyl diethyl ammonium ion, and ditetradecyl dipropyl ammonium ion. Ions, ditetradecyl dibutyl ammonium ion, and ditetradecyl dipentyl ammonium ion.
The quaternary organic ammonium ions having 13 carbon atoms as represented by XH in the formula (1) include ditridecyl ammonium ion, ditridecyl dimethyl ammonium ion, ditridecyl diethyl ammonium ion, ditridecyl dipropyl ammonium ion, ditridecyl ion. Dibutylammonium ion and ditridecyldipentylammonium ion.
The quaternary organic ammonium ions having 12 carbon atoms as represented by XH in formula (1) include didodecylammonium ion, didodecyldimethylammonium ion, didodecyldiethylammonium ion, didodecyldipropylammonium ion, didodecyl. Dibutylammonium ion and didodecyldipentylammonium ion.
The quaternary organic ammonium ions having 11 carbon atoms represented by XH in the formula (1) include diundecyl ammonium ion, diundecyl dimethyl ammonium ion, diundecyl diethyl ammonium ion, diundecyl dipropyl ammonium ion, diundecyl. Dibutylammonium ion and diundecyldipentylammonium ion.
The quaternary organic ammonium ions having 10 carbon atoms as represented by XH in formula (1) include didecyl ammonium ion, didecyl dimethyl ammonium ion, didecyl diethyl ammonium ion, didecyl dipropyl ammonium ion, didecyl ion. Examples thereof include dibutylammonium ion and didecyldipentylammonium ion.
Among these, quaternary organic ammonium ions having 16 or more carbon atoms are particularly preferable in that the interlayer spacing of the layered clay mineral is uniformly and maximized.

Further, a quaternary organic ammonium ion having 10 to 20 carbon atoms as represented by XH in the formula (1) can be used alone, but may be a mixture of several kinds.
For example, the component having 18 carbon atoms represented by XH in the formula (1) is 50 to 80 mol%, the component having 16 carbon atoms is 20 to 40 mol%, and the component having 14 carbon atoms is 0 to 10 mol. A mixture of quaternary organic ammonium ions such as beef tallow in which R ¹ and R ^{2 in} formula (1) are methyl groups and XH is terminal hydrogenated is even better.

  When the number of carbon atoms is 21 or more, the three-dimensional structure of the molecule becomes too large, making it difficult to introduce between layers, resulting in poor dispersibility. Conversely, when the number of carbon atoms is nine or less, the three-dimensional structure of the molecule is small. The layer spacing is too narrow and the dispersibility in the polymerization stage becomes poor, so that it does not contribute to viscosity reduction.

(Layered clay mineral)
The layered clay mineral is not particularly limited, and examples thereof include various clay minerals (layered silicate minerals) such as montmorillonite, bentonite, kaolinite, beidellite, nontronite, saponite, hectorite, soconite, and stevensite.
However, since the quaternary organic ammonium ions introduced between the layers have 10 to 20 carbon atoms, those having a large layer spacing are preferable. Particularly montmorillonite, preferably having a layer spacing of 1.6 nm or more before introduction of quaternary organic ammonium ions, more preferably 2.0 nm or more, particularly preferably 3.0 nm or more, Most preferable is 3.5 nm or more.

The amount used is 0.1 to 14 phr, more preferably 1 to 13 phr with respect to 100 parts by weight of polybutadiene (phr), since the effect of increasing the vulcanization rate and reducing the Mooney viscosity is exhibited even with a small amount. 1 to 12 phr is particularly preferable. Moreover, when the upper limit of the amount used is excessively large, there is a possibility that the color of rubber due to clay minerals will deteriorate. On the other hand, if the amount is too small, the effect cannot be obtained.
The organized clay described in the examples of the present invention means a form in which a quaternary organic ammonium ion is inserted into the layered clay mineral.

(Carbon black)
Carbon black is added as a rubber reinforcing material to the rubber composition according to the present invention.
The blending amount of carbon black is preferably 49 to 26 phr, more preferably 45 to 30 phr, and particularly preferably 49 to 40 phr with respect to 100 phr of polybutadiene.
In particular, the weight ratio between the rubber reinforcing material and the layered clay mineral into which quaternary organic ammonium ions are introduced (the layered clay mineral / rubber reinforcing material) is preferably 0.002 to 0.53, and 0.02 to 0.35. Is more preferable, and 0.02 to 0.32 is particularly preferable.
Within the above range, the effect of the rubber reinforcing material and the effect of the layered silicate mineral are well balanced, not only increasing the mechanical properties and suppressing heat generation, but also improving the workability by reducing the viscosity.

  Further, when silica is used as the rubber reinforcing material, the effect is not obtained so much.

  The type of carbon black used is carbon black having a particle diameter of 90 nm or less and a dibutyl phthalate (DBP) oil absorption of 70 ml / 100 g or more, for example, FEF, FF, GPF, SAF, ISAF, SRF, HAF and the like. It is done.

(Dispersant)
A dispersant such as polyethylene glycol is added to the rubber composition according to the present invention.
Polyethylene glycol is generally used as an activator in many cases, but in the present invention, it is not used as an activator but is used for the purpose of increasing the dispersion state of the organoclay in rubber.
The polyethylene glycol in the rubber and organized clay mixture system is inserted between the silicate layers of the organized clay and reduces the properties based on the hydroxyl groups of the silicate. As a result, the dispersibility of the silicate in the rubber matrix is improved. Furthermore, when the polymerization degree of polyethylene glycol is excessive, adsorption of the vulcanizing agent is prevented and the degree of crosslinking is improved.
As the dispersant to be used, polyether compounds such as polyethylene glycol are preferable.
The amount to be used is preferably 0.1 to 10 phr, more preferably 1.0 to 7 phr, and particularly preferably 1.5 to 5 phr with respect to 4 phr of the organized clay.
Outside the range of the amount used, it is difficult to obtain a dispersibility effect, and a low heat generation effect is also lowered, which is not preferable.

(Silane coupling agent)
The compounding amount of the silane coupling agent is preferably 0.1 to 10 phr, more preferably 1.0 to 7 phr, and particularly preferably 1.5 to 5 phr with respect to 46 parts by weight of the carbon black.
Outside the range of the amount used, it is difficult to obtain a dispersibility effect, and a low heat generation effect is also lowered, which is not preferable.

  Specific examples of the silane coupling agent include, for example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis ( 2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, 3-trimethyl Xylsilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3- Examples include trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, and 3-trimethoxysilylpropyl methacrylate monosulfide. These may be used alone or in combination of two or more. Among these, bis (3-triethoxysilylpropyl) tetrasulfide and 3-mercaptopropyltrimethoxysilane are preferable because they have a large effect by adding a silane coupling agent and are advantageous in terms of cost.

  As a kneading method for each component, any of a mechanical kneading method, a solution kneading method, or a kneading method using a combination of both may be used.

(Mechanical kneading method)
In the present invention, it is preferable to produce a rubber composition by mechanical kneading using a Banbury, an open roll, a kneader, a biaxial kneader or the like in which each component is usually performed.
This is because when mechanical kneading is used, the layered clay mineral containing quaternary organic ammonium ions is cleaved apart from each layer due to the frictional force between the components, and the dispersion state tends to be good.

The kneading temperature is preferably 90 ° C to 140 ° C.
In the mechanical kneading method, although the kneading start temperature is 90 ° C., the temperature inside the kneader rises to 140 to 150 ° C. within 5 minutes when the rubber, additive and rubber reinforcing material are kneaded. is there. Kneading at a temperature higher than the above temperature is not preferable because it causes thermal decomposition and deterioration of physical properties of the rubber composition. On the other hand, when the temperature is lower than the above temperature range, the rubber, additive, and rubber reinforcing material are difficult to blend due to low flow, which is not preferable.

As a specific mechanical kneading method, first, a rubber composition containing a filler (carbon black and organic clay) and an additive is prepared using a plastmill at an initial temperature of 90 ° C. for 5 minutes.
Thereafter, the diene rubber is kneaded for 1 minute, and then the premixed rubber composition of the filler and additive is added and mixed.

(Solution kneading method)
In the present invention, each component can be further kneaded in a state dissolved in a solvent.
Specific examples of the solvent include aliphatic or aromatic organic solvents such as benzene, toluene, and cyclohexane. Of these, nonpolar aliphatic saturated hydrocarbon solvents are preferred, and cyclohexane is particularly preferred.
This is because when the solution kneading method is used, the dispersion state of each component in the solution tends to be good.

  In the present invention, cyclohexane that dissolves diene rubber or organic clay is used because the organic clay peels off and the dispersion into the diene rubber becomes good.

The kneading temperature is preferably room temperature. When the temperature is higher than room temperature, the interaction between the inserted organic ammonium and the clay surface is weakened, and as a result, the diene rubber is prevented from entering the clay layer.
As a specific solution kneading method, diene rubber and organoclay were dissolved at a rate of 10 grams of diene rubber in 100 ml of cyclohexane at room temperature for 6 hours or more.
First, the diene rubber was dissolved in cyclohexane at room temperature for 1 hour, and then the organoclay was added and mixed.
After 6 hours, the diene rubber solution containing the organoclay was washed with ethanol, and then dried using an oven to remove the solvent.

(Mechanical kneading + Solution kneading method)
In the present invention, the rubber composition can also be produced by a method combining the mechanical kneading and the solution kneading methods.
Specifically, there are the following three methods.
(1) Method of putting composition obtained by solution kneading after mechanical kneading (2) Method of putting composition obtained by mechanical kneading after solution kneading (3) Obtained by solution kneading with mechanically kneaded composition In the present invention, all these three methods can be applied.

As a specific kneading method in the above (1), first, an organic clay is dispersed in a diene rubber using a two-roll mill or a plast mill at a kneading start temperature of 60 to 90 ° C.
Next, the diene rubber composition with the organic clay is dissolved in an organic solvent (toluene, cyclohexane, aliphatic saturated hydrocarbon, etc.), stirred for at least 6 hours, and then washed with ethanol to remove the solvent. Dry in the oven.
Thereafter, additives such as carbon black, zinc oxide, stearic acid, aroma oil and antioxidant are added to the diene rubber composition accompanied with the organic clay by using a plastmill at an initial temperature of 90 ° C. and an end temperature of 150 ° C. Mix for minutes.
The primary blend obtained by the production method was kneaded using a 6-inch two-roll mill at a kneading temperature of 30 to 60 ° C. and stretched into a sheet.

As a specific kneading method in the above (2), diene rubber and organoclay at a ratio of 10 grams of diene rubber to 100 ml of organic solvent (1 gram-diene rubber / 10 ml-organic solvent) at room temperature. For 6 hours or more.
Here, the organic solvent is an aliphatic or aromatic organic solvent such as benzene, toluene or cyclohexane. Cyclohexane is a particularly preferable solvent.
First, the diene rubber is dissolved in a solvent and stirred at room temperature for 1 hour. Then, the organoclay is added to it and stirred.
After 6 hours, the diene rubber solution containing the organoclay is washed and precipitated with ethanol, and then the solvent is removed in an oven.
Thereafter, additives such as carbon black, zinc oxide, stearic acid, aroma oil and antioxidant are added to the diene rubber composition containing the organic clay, and plastomyl is applied at an initial temperature of 90 ° C. and an end temperature of 150 ° C. And mix for 5 minutes.
The primary blend obtained by the production method was kneaded using a 6-inch two-roll mill at a kneading temperature of 30 to 60 ° C. and stretched into a sheet.

As a specific kneading method in the above (3), first, an organic clay is dispersed in a diene rubber using a two-roll mill or a plast mill at a kneading start temperature of 60 to 90 ° C., and carbon black, zinc oxide, stearin Additives such as acids, aroma oils and antioxidants are mixed for 5 minutes using a plastmill at an initial temperature of 90 ° C. and an end temperature of 150 ° C. This is a primary blend produced by mechanical kneading.
Next, the diene rubber and the organic clay were dissolved at a ratio of 10 grams (1 gram-diene rubber / 10 ml-organic solvent) with respect to 100 ml of the organic solvent at room temperature for 6 hours or more, and washed and the solvent was removed. To this, additives such as carbon black, zinc oxide, stearic acid, aroma oil and antioxidant are mixed at an initial temperature of 90 ° C. and an end temperature of 150 ° C. using a plastmill for 5 minutes. This is the primary blend produced by the solution kneading method.
The above primary blends were kneaded using a 6-inch two-roll mill at a kneading temperature of 30 to 60 ° C. and stretched into a sheet.

(Other additives)
In addition to the above-mentioned components, the rubber composition according to the present invention, in addition to reinforcing fillers such as carbon black, silica and polybutadiene resin, aroma oil, zinc oxide, stearic acid, anti-aging agent, wax, Various additives generally used in rubber compositions such as a tackifier (tackifier) can be appropriately blended.
As the vulcanization accelerator, known vulcanization accelerators such as aldehydes, ammonia, amines, guanidines, thioureas, thiazoles, thiurams, dithiocarbamates, xanthates and the like are used. It is 0-5 phr with respect to 100 phr of rubber components, Preferably it is 0.5-3 phr.
Further, as the vulcanizing agent, known vulcanizing agents such as sulfur, organic peroxides, resin vulcanizing agents, metal oxides such as magnesium oxide, and the like are used. 0.5 to 5 phr, preferably 1.5 to 3 phr with respect to 100 phr of the rubber component.
Examples of the anti-aging agent include amine / ketone series, imidazole series, amine series, phenol series, sulfur series and phosphorus series.
The process oil may be any of aromatic, naphthenic, and paraffinic.

(Example)
Examples of the present invention will be described below, but the present invention is not limited to these examples.

An evaluation method is shown below for each of the obtained rubber compositions.
(1) Measurement of heat generation temperature (rise) In accordance with JIS K6265, using a Goodrich flexometer, the temperature rises under the conditions of 100 ° C, strain 0.175 inch, load 55 pounds, frequency 1,800 times per minute. (ΔT) was measured. It shows that low exothermic property is so favorable that a numerical value is small.
(2) Measurement of modulus The tensile modulus (Modulus) was measured according to JIS K6251 at 50%, 100% and 300%.

(Comparative Example 1)
After mixing 100 parts by weight of commercially available cis-1,4-polybutadiene (UBEPOL BR150 manufactured by Ube Industries) as a diene rubber under the conditions of an initial temperature of 90 ° C. and an end temperature of 150 ° C. in a 250 ml plastmill, Parts by weight FEF carbon black, 4 parts by weight organoclay (Cloisite 15A), 10 parts by weight aroma oil, 1 part by weight zinc oxide, 2 parts by weight stearic acid, 1 part by weight oxidation inhibitor (4 A premixed rubber composition containing 6-bis (octylmethyl) -o-cresol) was added and the mixing time was 5 minutes in all steps.
The obtained blend was kneaded using a 6-inch two-roll mill at a kneading temperature of 30 to 60 ° C. and stretched into a sheet to obtain a primary blend.
Next, sulfur and a vulcanization accelerator are mixed in the primary blend as vulcanizing agents in the blending amounts shown in Table 1, and after kneading in a temperature range of 60 to 70 ° C. using a 6-inch two-roll mill, finally, Was stretched into a sheet to obtain a secondary blend.
A sample of this secondary blend was subjected to measurement of vulcanization time in the vulcanization process and analysis of the Payne effect using RPA-2000 manufactured by Alpha Technologies.
The rubber composition reinforced with the above organic clay is molded at 150 ° C. during the vulcanization time observed with a curast meter, preferably between 12 minutes and 34 minutes.
The physical properties of the rubber vulcanizate of the present invention, such as elastic properties and heat generation properties, were measured.

(Comparative Example 2)
The same procedure as in Comparative Example 1 was conducted except that 4 parts by weight of organoclay (Cloisite 15A) was changed to 1,2-polybutadiene.

(Example 1)
After mixing 100 parts by weight of commercially available cis-1,4-polybutadiene (UBEPOL BR150 manufactured by Ube Industries) as a diene rubber under the conditions of an initial temperature of 90 ° C. and an end temperature of 150 ° C. in a 250 ml plastmill, Parts by weight FEF carbon black, 4 parts by weight organoclay (Cloisite 15A), 2 parts by weight silane coupling agent, 2 parts by weight polyethylene glycol, 10 parts by weight aroma oil, 1 part by weight zinc oxide, 2 parts by weight A premixed rubber composition containing 1 part by weight of stearic acid and 1 part by weight of an antioxidant (4,6-bis (octylmethyl) -o-cresol) was added and the mixing time was 5 minutes in all steps.
The obtained blend was kneaded using a 6-inch two-roll mill at a kneading temperature of 30 to 60 ° C. and stretched into a sheet to obtain a primary blend.
Next, sulfur and a vulcanization accelerator are mixed in the primary blend as vulcanizing agents in the blending amounts shown in Table 1, and after kneading in a temperature range of 60 to 70 ° C. using a 6-inch two-roll mill, finally, Was stretched into a sheet to obtain a secondary blend.
A sample of this secondary blend was subjected to measurement of vulcanization time in the vulcanization process and analysis of the Payne effect using RPA-2000 manufactured by Alpha Technologies.
The rubber composition reinforced with the above organic clay is molded at 150 ° C. during the vulcanization time observed with a curast meter, preferably between 12 minutes and 34 minutes.
The rubber vulcanizate of the present invention was measured for various physical properties such as tensile elastic characteristics and heat generation characteristics.

(Comparative Example 3)
After mixing 100 parts by weight of commercially available cis-1,4-polybutadiene (UBEPOL BR150 manufactured by Ube Industries) as a diene rubber under the conditions of an initial temperature of 90 ° C. and an end temperature of 150 ° C. in a 250 ml plastmill, Parts by weight FEF carbon black, 4 parts by weight organoclay (Cloisite 15A), 2 parts by weight silica, 2 parts by weight silane coupling agent, 2 parts by weight polyethylene glycol, 10 parts by weight aroma oil, 1 part by weight A premixed rubber composition containing 2 parts by weight of zinc oxide, 2 parts by weight of stearic acid, and 1 part by weight of an antioxidant (4,6-bis (octylmethyl) -o-cresol) is added, and the mixing time is set to all steps. For 5 minutes.
The obtained blend was kneaded using a 6-inch two-roll mill at a kneading temperature of 30 to 60 ° C. and stretched into a sheet to obtain a primary blend.
Next, sulfur and a vulcanization accelerator are mixed in the primary blend as vulcanizing agents in the blending amounts shown in Table 1, and after kneading in a temperature range of 60 to 70 ° C. using a 6-inch two-roll mill, finally, Was stretched into a sheet to obtain a secondary blend.
A sample of this secondary blend was subjected to measurement of vulcanization time in the vulcanization process and analysis of the Payne effect using RPA-2000 manufactured by Alpha Technologies.
The rubber composition reinforced with the above organic clay is molded at 150 ° C. during the vulcanization time observed with a curast meter, preferably between 12 minutes and 34 minutes.
The rubber vulcanizate of the present invention was measured for various physical properties such as tensile elastic characteristics and heat generation characteristics.

  From Table 1, the exothermic property and tensile elastic modulus of the rubber composition can be improved by blending predetermined amounts of organic clay, carbon black, silane coupling agent and dispersant into polybutadiene.

The compounding components of the rubber composition are shown below.
(1) As polybutadiene, UBEPOL150 manufactured by Ube Industries, Ltd. was used.
(2) Cloisite 15A (registered trademark) manufactured by Southern Clay Products was used as the organized clay.
(3) As the carbon black, FEF carbon black manufactured by Mitsubishi Chemical Corporation was used.
(4) Silica was manufactured by Tosoh Silica Co., Ltd., and trade name NIPSEAL AQ.
(5) Sasex No. 1 manufactured by Sakai Chemical Industry was used as the zinc oxide.
(6) Adeka fatty acid SA-300 manufactured by Asahi Denka Co., Ltd. was used as stearic acid.
(7) Noxeller NS manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. was used as the vulcanization accelerator.
(8) Sulfur used was insoluble sulfur structol SU109 manufactured by S & S Japan.
(9) RB830 manufactured by JSR Corporation was used as 1,2-polybutadiene.
(10) The product name Si69 manufactured by Degussa Hyrun was used as the silane coupling agent.
(11) PEG 4000 manufactured by NOF Corporation was used as the polyethylene glycol.

  The rubber composition obtained in the present invention can be used not only for tire members but also for applications requiring elastic properties and low heat generation properties such as conveyor belts, air springs, and vibration-proof rubbers.

Claims (4)

Vulcanizable rubber (A), layered clay mineral (B) in which quaternary ammonium having the following general formula (1) is inserted, carbon black (C), silane coupling agent (D) and dispersant ( A rubber composition comprising E).

Wherein R ¹ and R ² are any one of at least one functional group selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl or pentyl groups, N is a nitrogen element, and HX is a carbon atom having 20 to 20 carbon atoms. Hydrocarbon compound having a terminal 10 and hydrogenated The vulcanizable rubber (A) is a polybutadiene having a cis-1,4 structure of 80% or more and a Mooney viscosity (ML _{1 + 4} , 100 ° C) of 25-80. The rubber composition as described in 2.   The rubber composition according to claim 1 or 2, wherein the interlayer of the layered clay mineral before the quaternary ammonium of (B) is inserted is 3 nm or more.   The rubber composition according to any one of claims 1 to 3, wherein the dispersant (E) is ethylene glycol.