JP2000204103A - Rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber composition capable of manufacturing a tire highly excellent in rolling-friction resistance (fuel consumption), wet-skid resistance and wear and abrasion resistance. SOLUTION: This rubber composition includes principal chain-modified diene- based copolymer obtained by reacting styrene-butadiene copolymer and/or styrene-isoprene-butadiene copolymer with an aliphatic compound having two amino groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rubber composition capable of producing a tire having particularly excellent rolling friction resistance characteristics (fuel consumption characteristics), wet skid characteristics and abrasion resistance.

[0002]

2. Description of the Related Art In recent years, with the demand for safety and low fuel consumption for automobiles, it has been desired to simultaneously improve wet skid characteristics, fuel consumption characteristics, and wear resistance of rubber materials for tires. Although they are rare, there is a problem that they are in conflict with each other.

Conventionally, styrene-butadiene copolymer (hereinafter, also referred to as SBR) and styrene-isoprene-butadiene copolymer (hereinafter, also referred to as SIBR) have been used as a method for obtaining a polymer that solves such a problem. Chemical modification with benzophenone (JP-A-58-162)
604, JP-A-59-117514) and chemical modification with an aromatic thioketone (US Pat. No. 37552)
No. 69), and terminal modification with nitroamino compounds, nitro compounds and nitroalkyl compounds (Japanese Patent Publication No. 6-53766,
Japanese Patent Publication No. 6-57769 and Japanese Patent Publication No. 6-78450) have been proposed, but none of these methods has obtained sufficient effects.

Conventionally, SBR has been modified by changing the amount of styrene and the method of bonding butadiene (such as the ratio of 1,2-butadiene bonds (bonds having a vinyl group) to 1,4-butadiene bonds) to obtain a wet skid. Characteristic,
It has been trying to achieve both tradeoffs in performance, such as fuel efficiency and wear resistance. Recently, in order to improve these performances, a method has been proposed in which the terminal is modified with a compound which easily binds to carbon black. However, since the denaturation is limited to the terminal, the effect of the denaturation is limited.

[0005] It is an object of the present invention to solve the above-mentioned problems in the prior art and achieve further improvements in wet skid characteristics, fuel consumption characteristics, and wear resistance.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a modified diene-based copolymer obtained by modifying SBR and / or SIBR with an aliphatic compound having two amino groups is contained. The present inventors have found that when a tire is produced using a rubber composition, a tire having characteristics excellent in wet skid characteristics, fuel consumption characteristics, and wear resistance can be obtained, and the present invention has been completed.

That is, the present invention relates to a main chain modified diene copolymer obtained by reacting a styrene-butadiene copolymer and / or a styrene-isoprene-butadiene copolymer with an aliphatic compound having two amino groups. A rubber composition containing the union (claim 1), and a styrene-butadiene copolymer and / or styrene-isoprene-
The rubber composition according to claim 1, wherein an aluminum halide or an alkyl halide is used as a catalyst when the butadiene copolymer is reacted with an aliphatic compound having two amino groups.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The main chain-modified diene copolymer used in the present invention is a styrene-butadiene copolymer (SB).
R) and / or a styrene-isoprene-butadiene copolymer (SIBR) (hereinafter also referred to as SBR, etc.) obtained by modifying the main chain with an aliphatic compound having two amino groups as a modifier. Is a modified diene copolymer.

The ratio of the styrene unit to the butadiene unit in the SBR is such that the styrene unit is 20 to 60% by weight.
(Hereinafter, referred to as%), more preferably 20 to 45%, and the butadiene unit is preferably 40 to 80%, more preferably 55 to 80%, from the viewpoint of the balance between wet skid performance and abrasion resistance.

The proportion of 1,2-bonds and 1,4-bonds in the butadiene unit is such that the 1,2-bonds are 10-80%
It is preferable that the 1,4-bond is 20 to 90% from the viewpoint of a balance between wet skid performance and fuel economy characteristics.

The ratio of the styrene unit, the isoprene unit and the butadiene unit in the above-mentioned SIBR is 5 to 50%, more preferably 10 to 40% for the styrene unit, 15 to 60% for the isoprene unit, further 20 to 50%, butadiene unit. The unit is preferably 5 to 50%, more preferably 20 to 40% from the viewpoint of the balance between wet skid performance and abrasion resistance.

The ratio of 1,4-bonds in the butadiene unit is preferably from 6 to 80% (remaining 1,2-bonds) from the viewpoint of a balance between wet skid performance and fuel efficiency.

The SBR and the like may be those generally produced commercially, or those appropriately synthesized. Among the various diene-based copolymers, SBR and the like are used because SBR and the like are preferable in terms of both low fuel consumption performance and wet skid performance.

The above-mentioned aliphatic compound having two amino groups, which is a modifier, is reacted with SBR or the like to modify the SBR or the like, thereby giving the SBR or the like a property of chemically bonding to a filler such as carbon black. Is a compound used for

Specific examples of the modifier include pentamethylenediamine, hexamethylenediamine, ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,4-diaminobutane, 1,7-diaminoheptane , 2,7-diaminoheptane, 1,8-
Diaminooctane, 1,9-diaminononane, 1,10
Examples thereof include aliphatic hydrocarbons having 2 to 12 carbon atoms, such as -diaminodecane and 1,12-diaminododecane, having two amino groups. These modifiers may be used alone or in combination of two or more.
Among them, 1,3-propanediamine and 1,4-diaminobutane are preferable because the reaction is easy and the amount used may be small.

The modification of the SBR or the like may be carried out by contacting and modifying the modifier with the SBR or the like in an organic solvent, or by adding the modifier directly to a polymerization solution of the SBR or the like. You may do it. In addition, as another method, it is also possible to directly knead and modify with an extrusion kneader or the like.

In carrying out the above-mentioned modification reaction, aluminum halide or alkyl halide may be used as a catalyst in order to increase the reaction rate.

Specific examples of the aluminum halide include, for example, aluminum chloride, aluminum bromide,
And aluminum iodide. Further, specific examples of the alkyl halide include compounds having an alkyl group having 1 to 6 carbon atoms, such as ethyl bromide, ethyl iodide, butyl chloride, butyl bromide, and butyl iodide. Among the catalysts, aluminum chloride,
Ethyl bromide is preferred.

The amount of the catalyst used is 0.01 to 100 mmol, preferably 0.05 to 100 mmol, per 100 g of SBR or the like.
50 mmol, especially 0.08 to 20 mmol, is preferred.

The organic solvent used in the modification reaction is not particularly limited as long as it does not react with SBR or the like, but is usually the same as the polymerization solvent used when polymerizing SBR or the like, for example, benzene, Chlorobenzene,
Aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as n-heptane, n-hexane, n-pentane and n-octane; alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, tetralin and decalin; Methylene and tetrahydrofuran can be used. Among these, toluene is preferred in terms of solubility of SBR and the like and reaction temperature (boiling point).

The solution temperature during the denaturation reaction is from 0 to 100
C, more preferably in the range of room temperature to 70C. If the temperature is too low, the progress of the modification reaction is slow, and if the temperature is too high, the modified diene copolymer tends to gel.

The time of the above-mentioned denaturation reaction is not particularly limited, but is usually preferably in the range of 0.5 to 6 hours. If the time is too short, the reaction does not proceed sufficiently, and if it is too long, the modified diene copolymer may gel.

The concentration of the above-mentioned SBR or the like dissolved in the above-mentioned organic solvent is such that the amount of SBR or the like per liter of the organic solvent is 5 to 500 g, more preferably 20 to 200 g, especially 30 to 100 g. It is preferable because the reaction proceeds smoothly.

The amount of the modifier is 100 g such as SBR.
0.01 to 150 mmol, more preferably 0.5 to
Preferably it is 100 mmol, in particular 1 to 50 mmol. If the amount is less than 0.01 mmol, the amount of nitrogen element introduced into SBR or the like during the modification becomes small, and it becomes difficult to obtain a sufficient modification effect.
If the amount is more than 50 mmol, the amount of the unreacted modifier remaining in the modified diene-based copolymer increases, so that it takes time to remove the modifier, and the influence on the subsequent vulcanization reaction increases.

The thus obtained main chain-modified diene polymer used in the present invention has a nitrogen content of at least 10 ppm, wherein an aliphatic compound having two amino groups in the main chain such as SBR is bonded. , Preferably 10 ppm or more and 200
It is a main chain modified diene polymer having a characteristic of 0 ppm or less.

The fact that the modified diene-based polymer is a main-chain modified diene-based polymer means that, for example,
When reacted with 3-propanediamine, ¹³ C-N
A peak at which an amino group was bonded to a carbon atom in butadiene rubber was observed at around 58 ppm by MR measurement, and a peak of a hydrogen atom bonded to the carbon atom at position 1 in 1,3-propanediamine was measured by ¹ H-NMR measurement. This is confirmed from the observation at around 4 ppm.

When the amino group bonded to the carbon atom at the 3-position in 1,3-propanediamine also participates in the modification of the main chain, a crosslinked structure can be formed.

Specific examples of the main chain-modified diene polymer include, for example, those used in Examples described later. These may be used alone or in combination of two or more.

The rubber composition of the present invention is generally used as a rubber composition by using the main chain-modified diene copolymer alone or blended with another synthetic rubber such as polybutadiene rubber or natural rubber as a rubber component. A composition containing a filler to be used, for example, a filler such as carbon black and silica, and a silane coupling agent compounded to enhance the bond between silica and the main chain-modified diene copolymer and improve abrasion resistance. It is.

When the main chain modified diene copolymer and the synthetic rubber or natural rubber are used in combination, the weight ratio of the modified diene copolymer / synthetic rubber or natural rubber is 80/20 to 40/60. , And 70 / 30-50 /
The value of 50 is preferred from the viewpoint that the effect of the modified diene copolymer is sufficiently exhibited.

The carbon black has a nitrogen adsorption specific surface area (hereinafter referred to as N ₂ SA) of 30 to 200 m ^2.
/ G of compressed dibutyl phthalate oil absorption (hereinafter referred to as 24M4
Those having a DBP oil absorption of 30 to 150 ml / 100 g are preferably used. When the N ₂ SA and 24M4DBP oil absorptions are smaller than the respective lower limit values, the dispersibility improving effect and the reinforcing effect are small, and when the N ₂ SA and 24M4DBP oil absorption amounts exceed the upper limit values, the dispersibility is not good and the heat buildup tends to increase. is there.

Specific examples of the carbon black include:
Examples include, but are not limited to, HAF, ISAF, SAF, and the like.

The compounding amount of the carbon black is as follows:
10 to 100 parts, more preferably 25 to 80 parts per 100 parts of the main chain-modified diene-based copolymer (when blended with another rubber, when used as a blend, the same applies hereinafter). It is preferable from the viewpoint of low heat generation.

As the silica, N ₂ SA is 50-3.
Those having a flow rate of 00 m ² / g are preferably used. N ₂ SA is 5
When it is less than 0 m ² / g, the dispersibility improving effect and the reinforcing effect are small, and when it exceeds 300 m ² / g, the dispersibility is not good and the heat generation tends to increase.

Examples of the silica include dry silica (silicic anhydride) and wet silica (hydrous silicic acid). There is no particular limitation, but wet silica is preferred. Preferred examples of the wet process silica include Ultrasil VN3 (trade name) manufactured by Degussa Corporation and Nip Seal VN3 AQ (trade name) manufactured by Nippon Silica Co., Ltd.

The amount of the silica is preferably 5 to 100 parts, more preferably 10 to 85 parts, per 100 parts of the main chain-modified diene copolymer, from the viewpoint of low heat generation and workability. .

The amount of the silane coupling agent is preferably 3 to 20%, more preferably 4 to 15%, based on the silica. When the amount of the silane coupling agent is less than 3%, the effect of the addition of the silane coupling agent cannot be sufficiently obtained. When the amount exceeds 20%, the effect is hardly obtained despite the increase in cost.

As the silane coupling agent, those conventionally used in combination with silica (filler) can be used without particular limitation.

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-mercapto Propyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-
Nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2
-Chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, -Triethoxysilylethyl-N, N-dimethylthiocarbamoyltetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3- Trimethoxysilylpropyl methacrylate monosulfide and the like. These may be used alone or in combination of two or more. Among them, bis (3-triethoxysilylpropyl) tetrasulfide and 3-mercaptopropyltrimethoxysilane have a large effect by adding a coupling agent,
It is preferable because it is superior in cost.

In the rubber composition of the present invention, in addition to the above-mentioned carbon black, silica, and silane coupling agent, if necessary, additives generally used as additives of the rubber composition may be added in a range generally used. It may be added.

Specific examples of the additives include, for example, process oils (paraffinic process oils, naphthenic process oils, aromatic process oils), vulcanizing agents (sulfur, sulfur chloride compounds, organic sulfur compounds, etc.), Sulfur accelerators (guadinin, aldehyde-amine, aldehyde-ammonia, thiazole, sulfenamide, thiourea, thiuram, dithiocarbamate, xanthate compounds, etc.), antioxidants or antioxidants (Diphenylamine-based, p-phenylenediamine-based amine derivatives, quinoline derivatives, hydroquinone derivatives, monophenols, diphenols, thiobisphenols, hindered phenols,
Phosphites, etc.), vulcanization aids (stearic acid,
Zinc oxide such as zinc oxide).

The rubber composition of the present invention is prepared by blending the main chain-modified diene copolymer alone or by blending it with the synthetic rubber or the natural rubber. Then, the filler such as carbon black and silica, It is obtained by adding a ring agent and, if necessary, the above-mentioned additives, and kneading the mixture by a conventional method.For example, mechanical properties and abrasion resistance of tires, hoses, belts and other various industrial products are required. It can be suitably used for various applications.

[0043]

EXAMPLES Hereinafter, the rubber composition of the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

The raw materials used in the examples and comparative examples are summarized below.

SBR1502: trade name, manufactured by Nippon Synthetic Rubber Co., Ltd., styrene-butadiene copolymer, styrene unit content: 23.5% carbon black: Showa Cabot Co., Ltd. Showa Black N220 Antioxidant: manufactured by Nippon Ciba Geigy Irganox1
010 (tetrakis- [methylene-3- (3 ', 5'-
Di-tert-butyl-4'-hydroxyphenyl) propionate] methane) Stearic acid: Stearic acid manufactured by NOF Corporation Zinc oxide: Zinc flower No. 1 manufactured by Mitsui Kinzoku Mining Co., Ltd. Antioxidant 6C: Ouchi Nocrack 6C (N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine) manufactured by Shinko Chemical Industry Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Co., Ltd. Vulcanization accelerator TBBS: Large Noxeller NS (N-tert-butyl-2-benzothiazyl sulfenamide) manufactured by Uchi Shinko Chemical Industry Co., Ltd.

The methods for evaluating the properties of the main chain-modified diene copolymer obtained in Examples and the methods for evaluating the rubber compositions obtained in Examples and Comparative Examples are described below.

[Method of Evaluating Properties of Main Chain-Modified Diene Copolymer] (Mooney viscosity (ML _{1 + 4} , 100 ° C.)) Measured according to JIS K 6300 using main chain-modified diene copolymer. .

(Nitrogen Content) The nitrogen content of the main chain-modified diene copolymer was measured by the Kjeldahl method according to JIS K0102.

[Method of Evaluating Rubber Composition] (Tensile Properties) M300 (300% tensile stress) of a vulcanized product of a predetermined rubber composition according to JIS K6301
Pa), was determined T _B (tensile strength) (MPa) and E _B (elongation) (%). Further, it determined the value of T _B × E _B. The larger the value, the better the destruction characteristics.

(Rolling Resistance Index) Using a viscoelastic spectrometer VES manufactured by Iwamoto Seisakusho, at a temperature of 70 ° C.
The tan δ of the vulcanized product of the rubber composition was measured under the conditions of an initial strain of 10% and a dynamic strain of 2%.
The rolling resistance index was expressed by the following formula: Rolling resistance index = {(value of comparative example 1) / (value of each example)} × 100. The larger the index value, the lower the rolling resistance.

(Wear index) Abrasion amount (volume loss) of a vulcanized product of a predetermined rubber composition using a Lambourn abrasion tester at a temperature of 20 ° C., a slip ratio of 20%, and a test time of 5 minutes.
Was measured, and the loss amount of Comparative Example 1 was set to 100, and was expressed as a wear index by the formula: Wear Index = {(Loss of Comparative Example 1) / (Loss of Each Example)} × 100. The larger the index value, the better the wear resistance.

(Wet skid index) ASTM E3 using a portable skid tester manufactured by Stanley.
The wet skid performance of the vulcanizate of the predetermined rubber composition was measured according to the method of 03-83, and the numerical value of Comparative Example 1 was set to 100, and the formula: Wet skid index = ｛the numerical value of each example / the numerical value of Comparative Example 1 It was expressed as a wet skid index by the numerical value｝ × 100. The larger the index value, the better the wet skid performance.

Example 1 100 g of SBR1502 and 1 liter of toluene were added to a 2-liter glass separable flask equipped with a stirrer and a temperature controller, and the temperature was raised to 60 ° C. with stirring to complete the SBR1502. Was dissolved. Thereto, 1 mmol of 1,3-propanediamine previously dissolved in tetrahydrofuran as a modifier and 10 mmol of aluminum chloride as a catalyst were added.
Allowed to react for hours. After completion of the reaction, the reaction solution was cooled to room temperature, and the reaction solution was filtered with a 250-mesh metal steel, and 2 liters of methanol was added to precipitate a main chain-modified diene copolymer.
After that, the dissolution in toluene and the precipitation in methanol were repeated again to remove the denaturing agent remaining without reacting. Then, an antioxidant was kneaded at 1000 ppm with respect to the main chain-modified diene copolymer. After that, the mixture was vacuum-dried at 100 ° C. for 1 hour to obtain a main chain-modified diene copolymer (I) used in the present invention.

The main chain-modified diene copolymer (I) obtained
Was evaluated in accordance with the above [Method for evaluating properties of main chain-modified diene copolymer].

Next, according to the main chain-modified diene copolymer (I) and the composition shown in Table 1, other raw materials were used.
The mixture was kneaded using a 50 cc Banbury type kneader to obtain a test rubber composition. The obtained test rubber composition was press-vulcanized at 170 ° C. for 20 minutes to obtain a vulcanized product (I),
The evaluation was performed according to the above [Rubber composition evaluation method].
Table 1 shows the results.

Example 2 Except that 20 mmol of ethyl bromide was used as catalyst.
The same operation as in Example 1 was performed to obtain a main chain-modified diene copolymer (II) and a vulcanized product (II), and each was similarly evaluated. Table 1 shows the results.

Example 3 A main chain modified diene copolymer (III) was prepared in the same manner as in Example 1 except that 5 mmol of 1,4-diaminobutane was used as a modifier and 10 mmol of aluminum chloride was used as a catalyst. ) And vulcanizate (III) were obtained and evaluated similarly. Table 1 shows the results.

Example 4 The same operation as in Example 1 was carried out except that 5 mmol of 1,4-diaminobutane and 10 mmol of ethyl bromide were used as a modifier and a catalyst, respectively. IV) and vulcanizate (IV) were obtained, and each was similarly evaluated. Table 1 shows the results.

Example 5 As a modifier, 20 mmol of 1,2-propanediamine was used.
The same operation as in Example 1 was carried out except that 20 mmol of aluminum chloride was used as a catalyst to obtain a main chain-modified diene copolymer (V) and a vulcanized product (V), which were similarly evaluated. Table 1 shows the results.

Example 6 1,2-propanediamine (20 mmol) as a modifier
A main chain modified diene copolymer (VI) and a vulcanized product (VI) were obtained in the same manner as in Example 1 except that 20 mmol of aluminum bromide was used as a catalyst, and each was similarly evaluated. . Table 1 shows the results.

Comparative Example 1 A vulcanized product was obtained in the same manner as in Example 1 except that SBR1502 was used in place of the main chain-modified diene copolymer, and a vulcanized product was evaluated in the same manner. Table 1 shows the results.

[0062]

[Table 1]

[0063]

According to the present invention, a rubber composition having excellent wet skid characteristics, low rolling resistance and abrasion resistance can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08F 212/08 C08F 212/08 236/04 236/04 (72) Inventor Atsushi Inoue Goi Minami, Ichihara-shi, Chiba No. 1 on the shore Ube Industries, Ltd. Chiba Petrochemical Factory (72) Inventor Tetsuji Nakajima No. 8, No. 1, Goi South Coast, Ichihara City, Chiba Prefecture Ube Industries, Ltd. Chiba Petrochemical Factory F-term (reference) 4J002 AC081 BC051 BC101 BP011 EN036 GN01 4J100 AB02P AS02Q AS02R AS03Q BA29H CA04 CA05 CA31 HA61 HC05 HC43 HC44 HC84 HE41 HG02 HG03 JA29

Claims (2)

[Claims] 1. A main chain-modified diene copolymer obtained by reacting a styrene-butadiene copolymer and / or a styrene-isoprene-butadiene copolymer with an aliphatic compound having two amino groups. Rubber composition. 2. An aluminum halide or an alkyl halide is used as a catalyst when reacting a styrene-butadiene copolymer and / or a styrene-isoprene-butadiene copolymer with an aliphatic compound having two amino groups. The rubber composition according to claim 1.