JPH0562601B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing diene polymer rubber, and more specifically, a diene polymer having an active alkali metal and/or alkaline earth metal terminal, a tin compound, and a specific The present invention relates to a method for producing diene polymer rubber characterized by reacting it with an aromatic amino compound. (Prior Art) In recent years, due to demands for lower fuel consumption and driving safety for automobiles, rubber materials with low rolling friction resistance and high wet skid resistance have been strongly desired as rubber for automobile tire leads. However, these two properties are contradictory, and various methods for improving polymers have been proposed in order to harmonize these two properties. For example, a method for adjusting the vinyl content and styrene content of a styrene-butadiene copolymer to a specific ratio (Japanese Patent Laid-Open No. 54-62248), a method for achieving a specific styrene chain distribution (Japanese Patent Laid-Open No. 56-143209), A method for creating a bonded chain distribution (Japanese Patent Application Laid-Open No. 149413/1983),
Butadienyl-
A method of introducing a tin bond (Japanese Unexamined Patent Publication No. 1987-87407) has been proposed. The present inventors have developed an alkali metal addition diene polymer and a specific aromatic amino compound
162604) and introduced a specific atomic group into the polymer. (Problems to be Solved by the Invention) However, the diene polymer rubber modified using the above-mentioned compound has better wrapping properties on oven rolls and extrusion using an extruder than the original rubber that is not modified. It has a serious practical drawback of poor workability, which is represented by its shape. If the Mooney viscosity of the polymer is lowered, it is possible to improve the processability while retaining the effect of improving the rebound properties provided by the modifier, but new drawbacks arise such as large cold flow properties and poor storage properties. The inventors of the present invention have arrived at the present invention as a result of extensive research into a method for producing a diene polymer rubber that has an excellent balance between rolling resistance and wet skid resistance, as well as good processability and storage stability, using the above-mentioned compound. (Means for Solving the Problems) An object of the present invention is to provide a method for producing diene polymer rubber that has an excellent balance between rolling resistance and wet skid resistance, and also has good processability and storage stability. is a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in a hydrocarbon solvent using an alkali metal and/or alkaline earth metal initiator, and the obtained alkali metal and/or alkaline earth metal An active diene polymer rubber having a metal terminal and (1) general formula
RaSnXa (wherein R is an alkyl group, alkenyl group, cycloalkyl group or aromatic hydrocarbon group,
X is a halogen atom, a is an integer from 0 to 2, and b is from 2 to
and (2) at least one compound selected from the group consisting of aromatic aminoaldehydes, aromatic aminoketones, and thioaldehydes and thioaminoketones of these reactions (hereinafter referred to as reactants). This is achieved by reacting with The object of the present invention is achieved by reacting an active diene polymer rubber having an alkali metal and/or alkaline earth metal terminal with a tin compound and a reactant, and in which the rubber is reacted with the tin compound or the reactant, respectively. However, the purpose cannot be achieved. (Function) The structure of the polymer after the reaction becomes high in molecular weight due to the reaction with the tin compound, exhibiting a bimodal molecular weight distribution, and the polymer chain ends that are not involved in the reaction with the tin compound contain amino acids as reactants. Taking thioaldehyde as an example,

[Formula] (In the formula, M represents an O atom or an S atom, R and R' represent a hydrogen atom or the same or different substituents)
The reactant is added in this way. The ratio of the molecular chain whose molecular weight has been increased by the reaction with the tin compound to the molecular chain which the reactant has added to the end of the polymer may be arbitrary, but the ratio (weight) is 1:9 to 9:1.
is preferred. Also, the proportion of the polymer to which the reactant is attached at the polymer end is at least 20 weight percent relative to the polymer that does not participate in the reaction with the tin compound. The order of the reaction with the tin compound and the addition reaction with the reactant may be arbitrary; there are two methods: performing the addition reaction after the reaction with the tin compound, conversely, performing the reaction with the tin compound after the addition reaction, and performing the two reactions at the same time. Any of the three methods may be used. Of course, the above two reactions can be expressed as 2
When carried out in stages, it is necessary to control the amount of the compound added in the first stage so that after the first stage reaction, active polymer chains with unreacted alkali metal ends remain. The active diene polymer having an alkali metal and/or alkaline earth metal terminal used in the present invention is a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl compound using an alkali metal initiator commonly used in solution polymerization (e.g. (disclosed in Japanese Patent Publication No. 44-4996, etc.) or barium, strontium,
It is obtained by polymerization using an alkaline earth metal catalyst whose main component is a compound such as calcium. A polar compound such as an ether compound, an amine compound, or a phosphine compound may be present as a vinylating agent in the case of polymerizing a conjugated diene monomer or as a randomizer in the case of copolymerizing a conjugated diene monomer and an aromatic vinyl monomer. The content of aromatic vinyl compounds is less than 50% by weight, preferably from 5 to 35% by weight.
Conjugated diene monomers include 1,3-butadiene, isobrene, 1,3-pentadiene, 2,3
-dimethyl-1,3-butadiene, 1,3-hexadiene, etc. Aromatic vinyl compounds include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, vinylnaphthalene, and the like. Organolithium initiators are particularly common as alkali metal initiators used in the present invention, such as methyllithium, ethyllithium, n-propyl, i-propyllithium, n-butyllithium, sec-butyllithium, t -butyllithium,
Octyllithium, n-decyllithium, phenyllithium, 2-naphthyllithium, 2-butyl-phenyllithium, 4-phenyl-butyllithium, cyclohexyllithium, 4-cyclopentyllithium, 1,4-dilithio-butene-2, etc. Examples include, but are not limited to. Examples of alkaline earth metal initiators include (1)
Ba tertiary alkoxide disclosed in JP-A-52-48910/
A complex consisting of dibutyl Mg, (2) with organic Li disclosed in JP-A-52-9090, etc.

[Formula] [At least one R in the formula represents a methyl or cyclohexyl group, the remaining R represents a _C1-6 alkyl group, etc., a:b=99.5-88:0.5-12 (molar ratio)
It is. ], (3) JP-A-56-112916
Composite initiator consisting of Ba alcoholate or phenolate/organic Li or Mg/organic Al disclosed, (4) JP-A-17591, 30543, 98077, JP-A-56-
112916, and those disclosed in Japanese Patent Application Laid-Open No. 57-98077. The amount of alkali metal initiator used usually ranges from 0.2 to 20 mmol per 100 grams of monomer. Polymerization is usually carried out at a temperature range of -20°C to 150°C, preferably a temperature range of 40°C to 120°C. Polymerization can be carried out either at elevated or constant temperature. The hydrocarbon solvent used in the present invention is selected from aliphatic hydrocarbons, aromatic hydrocarbons, and alicyclic hydrocarbons, particularly propane, n-butane, i-butane, and n-butane having 2 to 12 carbon atoms. - pentane, i
-Pentane, n-hexane, cyclohexane, propene, 1-butene, i-butene, trans-2
-butene, cis-2-butene, 1-pentene, 2
-Pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene and the like are preferred. Moreover, these solvents can also be used in combination of two or more types. The tin compound used in the present invention has the general formula RaSnXb
(However, in the formula, R is an alkyl group, alkenyl group, cycloalkyl group, or aromatic hydrocarbon group, X is a halogen atom, a is an integer of 0 to 2, and b is an integer of 2 to 4). It is used to increase the molecular weight of polymers. Specifically, methyltrichlorotin, dimethyldichlorotin, tetrachlorotin, dichlorotin, ethyltrichlorotin, diethyldichlorotin, tetrafluorotin, butyltrichlorotin, dibutyldichlorotin, octyltrichlorotin, dioctyldichlorotin, Methylchlorotin, dimethyldibrometin,
Octyltribrometin, tetrachloride, tetrabromotin, tetraiodotin, cyclohexyltrichlorotin, phenyltrichlorotin, 1,2-bis(trichlorostannyl)ethane, 1,2-bis(methylchlorostannyl)ethane, 1 , 4-bis(trichlorostannyl)butane, 1,4-bis(methyldichlorostannyl)butane, etc. are used. The reaction between the tin compound and the metal-terminated polymer can be normally carried out at 0 to 150°C for 0.5 minutes to 20 hours.
The amount of the tin compound to be used is usually in the range of 0.1 to 0.9 equivalents based on the halogen atom of the tin compound per mole of the metal-terminated active diene polymer rubber, and the molecular weight is increased depending on the amount of the tin compound. The proportion of polymers added can be controlled. If the amount of the tin compound used is less than 0.1 equivalent based on the halogen atom, processability and storage properties will be poor, and if it is more than 0.9 equivalent, the impact resilience will be poor. The polymerization reaction due to tin compounds is 0~
It is carried out at 150°C for 0.5 minutes to 20 hours. The reactants used in the present invention, aromatic aminoaldehydes, aromatic aminoketones, and their corresponding thioaldehydes or thioketones, contain 1 to
It is an aromatic compound with four amino groups. Examples of the substituent bonded to the nitrogen atom include hydrogen or an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group, an aralkyl group, an alkoxyalkylene group, and the like. The di-substituted substituents may be the same or different. The aromatic nucleus may have four or less substituents other than the amino group. Specific compounds include 4,4'-diaminobenzophenone, 4,4'-bis(dimethylamino)-benzophenone, 4,4'-bis(diethylamino)-benzophenone, 3-diethylaminobenzophenone, 3, 3',5,5'-tetra(dinonylamino)
Benzophenone, aminoanthraquinone, N,N
-dimethylaminoanthraquinone, 1,4-diaminoanthraquinone, 1,4-N,N-dimethyldiaminoanthraquinone, 1,4-N,N,N',
N'-tetramethyldiaminoanthraquinone, phenoxazine, N-methylphenoxazine, 10-
Butylphenoxazine, 3,7-diamino-10-
Acetylphenoxazine, acridone, N-methylacridone, 4-aminobenzaldehyde, 4
-dimethylaminobenzaldehyde, 3,5-bis(dihexylamino)-benzaldehyde, 2,
Examples include 4,6-tris(diethylamino)benzaldehyde, 4-dicyclobentylaminobenzaldehyde, 4,5-bis(diethylamino)-1-naphthaldehyde, and their corresponding thioketones and thioaldehydes. The compound is not particularly limited as long as it reacts with the metal. Particularly preferred are N,N-disubstituted amino compounds. The amount of the reactant to be used is in the range of 0.1 to 0.9 mole per mole of the metal-terminated active diene polymer rubber. The amount of these compounds used is 0.1
If it is less than 0.9 mol, the impact resilience will be poor, and if it is more than 0.9 mol, the processability and storage properties will be poor. The reaction temperature and reaction time can be selected over a wide range, but generally from room temperature to
The temperature is 100℃ for several seconds to several hours. In the present invention, the use of a diene polymer rubber having a dienyl-metal bond at the end of the polymer chain further enhances the effects of the present invention, so it is particularly desirable to use this rubber. After the reaction is completed, the modified diene polymer rubber is separated from the reaction solution by adding a coagulant such as alcohol or by coagulating with steam coagulation, using the coagulation method used in the production of rubber by normal solution polymerization. . The solidification temperature is also not particularly limited.
The crumbs separated from the reaction system are dried using a band dryer, which is normally used in the production of synthetic rubber.
An extrusion type dryer can be used, and the drying temperature is not particularly limited. The diene polymer rubber thus obtained has an excellent balance of rolling resistance and wet skid resistance, and also has good processability and storage stability, and is very useful as a rubber material for tire tops. Next, the present invention will be explained in more detail with reference to Examples. Example 1 A stainless steel polymerization reactor with an internal volume of 2 was washed, dried, and replaced with dry nitrogen, and then 120 g of 1,3-butadiene, 40 g of stene, 840 g of cyclohexane,
Tetramethylethylenediamine 0.5 mmol, n
1.2 mmol of -butyllithium (n-hexane solution) was added, and polymerization was carried out at 45° C. for 5 hours while stirring the contents. After the polymerization reaction was completed, tin tetrachloride was added in the amount shown in Table 1, and the reaction was allowed to proceed for 30 minutes.The compounds shown in Table 1 were further added and the addition reaction was allowed to proceed for 30 minutes. Thereafter, 5 ml of methanol was added to stop the reaction, and the polymer solution was taken out into a 1.5% by weight methanol solution of 2,6-di-t-butyl-p-cresol (BHT), and the resulting polymer was coagulated. It was dried under reduced pressure at ℃ for 24 hours. The vinyl bond content and styrene content of the polymer thus obtained were determined by infrared spectroscopy [Hampton, Anal.Chem., 21 , 923 (1949)]. Further, the polymerization rate (coupling rate) was determined from the area fraction of the high molecular weight portion with respect to the total area of the gel permeation chromatogram. The measurement conditions for gel permeation chromatography are as follows. Column: 2 GMH-6 manufactured by Toyo Soda Temperature: 38℃ Flow rate: 1.2ml/min In addition, the addition rate of the reactant was determined by attaching an ultraviolet absorption analyzer to the detection part of gel permeation chromatography and measuring the absorption intensity at 310nm. Calculated from molecular weight.
Table 1 shows the polymer structure and Mooney viscosity (ML _1+4,100 °C) of the resulting polymer rubber.

[Table] The obtained polymer was mixed according to the formulation shown in Table 2.
Each compounding agent was kneaded and mixed in a Brabender type mixer with a capacity of 250 ml to obtain a rubber compound composition. This material was press-vulcanized at 160°C for 25 minutes to prepare a test piece. Table 2 Compounding recipe Polymer rubber 100 parts by weight Zinc white No. 3 3 Stearic acid 2 Sulfur 1.75 HAF cutlet black 50 Aromatic process oil 5 N-cyclohexyl-2-benzothiazole sulfenamide 1.1 The processability of the rubber compound composition was evaluated by compound Mooney viscosity, roll wrapability, and extrusion processability. Roll windability is at a temperature of 50℃ and a roll gap of 1.5mm.
The blended composition was wound around a 6-inch roll, and the condition was evaluated after 1 minute. The condition in which the compounded composition wrapped around the roll is tightly wrapped around the roll is rated as "excellent".
A state in which the material was wound while sometimes lifting up from the roll was rated as "good," and a so-called bagging state in which the material did not wrap around the roll at all was rated as "poor." Evaluation of extrusion processability was performed according to Method A described in ASTM D2230-78. Extrusion was performed at a barrel, head, and die temperature of 100°C and a screw rotation speed of 30 rpm to determine the shape of the extrudate.
Evaluation was made according to Rating System A of ASTM D2230-78. Total score of 4 evaluation items for shape is 16~
A rating of 14 was considered "excellent," 13 to 11 was considered "good," and a rating of 10 or less was considered "poor." The cold flow property was determined by the flow of a No. 3 dumbbell described in JIS K-6301 punched from a 2 mm sheet of polymer. 2mm sheet of polymer is heated to 100℃,
It was prepared by hot pressing for 5 minutes and cooling with water for 30 minutes or more while maintaining the pressurized state. One end of the dumbbell was fixed and suspended in an atmosphere at 23°C, and an index of cold flow properties was determined from the elongation of the dumbbell. The elongation was determined from the length of the marked lines marked in advance at the center of the dumbbell at intervals of 20 mm. If the elongation after 300 minutes after hanging was less than 10%, it was considered "small," if it was 10% or more but less than 40%, it was considered "medium," and if it was 40% or more, it was "large." The impact resilience of the vulcanized rubber was measured at 50°C using a Dunlop tribometer. Wet skid resistance was measured using a portable skid tester manufactured by Stanley Corporation at 23° C. and on a road surface (ASTM E-303-74, outdoor type B, black, Safety Walk, manufactured by 3M Corporation). The results are shown in Table 3.

[Table] From the results in Table 3, it can be seen that the butadiene-styrene copolymer obtained by the method of the present invention has an excellent balance of rolling resistance (rebound resilience) and wet skid resistance, and also has good processability and storage stability. Example 2 Polymerization was carried out under the same conditions as Example 1 except that 160 g of 1,3-butadiene was used as a monomer,
After the polymerization reaction was completed, 0.1 mmol of tin tetrachloride was added.
The reaction was allowed to take place for 30 minutes. Subsequently, the compounds shown in Table 4 were added and reacted for 30 minutes. The structure of the obtained polybutadiene rubber is shown in Table 4. These rubbers were evaluated in the same manner as in Example 1, and the results shown in Table 5 were obtained. As is clear from Table 5, the butadiene polymer obtained by the method of the present invention has rolling resistance (repulsion resilience)
It can be seen that the material has an excellent balance between wet skid resistance and wet skid resistance, and also has good processability and storage stability.

【table】

[Table] Example 3 After the completion of the polymerization reaction, tin tetrachloride (0.1
4,4'-bis(dimethylamino)benzophenone (0.6 mmol) to obtain a styrene-butadiene copolymer rubber (high molecular weight conversion rate: 40%, addition rate: 52%). Processability, vulcanization properties, and cold flow properties were evaluated in the same manner as in Example 1, and the results shown in Table 6 were obtained. (Experiment number 24)

[Table] As is clear from Table 6, by introducing the butadiene-tin bond and the butadiene-4,4-bis(dimethylamino)benzophenone bond,
It can be seen that a copolymer rubber with an even better balance between impact resilience and wet skid resistance, and good processability and storage properties can be obtained. Example 4 A stainless steel bolt polymerization reactor with an internal volume of 1.4 was washed, dried, and replaced with dry nitrogen.
- 80 g of butadiene, 20 g of styrene and 600 g of cyclohexane were charged. After that, dibutylmagnesium/triethylaluminum complex [Mg/Al
= 5.0 (molar ratio)] to 2.2 mmol (Mg standard), t-
0.44 mmol of butoxybarium was added, and polymerization was carried out at 80° C. for 5 hours with stirring. After the completion of polymerization, the seventh
The amount of tin tetrachloride listed in the table was added and allowed to react for 60 minutes. Furthermore, the compounds listed in Table 7 were added, and 30
Allowed to react for minutes. The subsequent operations were performed in the same manner as in Example 1 to obtain the desired polymer. The microstructure, coupling rate, and Mooney viscosity of the polymer were measured in the same manner as in Example 1. The results are also listed in Table 7. A blended composition of the obtained polymer was prepared according to the blending recipe shown in Table 2, and was press-vulcanized at 160°C for 25 minutes to prepare a test piece. The properties of the unvulcanized compounded composition and the vulcanized product were evaluated in the same manner as in Example 1. The results are shown in Table 8. Polymerization, coupling, and reaction with the compound were carried out under the same conditions except that 100 g of 1,3-butadiene was used instead of the above monomer. The obtained polybutadiene (trans content 86%) showed similar results to those listed in Table 8.

【table】

【table】

Claims (1)

[Claims] 1. Polymerization of a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer using an alkali metal and/or alkaline earth metal initiator in a hydrocarbon solvent, and the resulting alkali metal and / or an active diene polymer rubber having an alkaline earth metal terminal;
(2) aromatic aminoaldehyde, aromatic A method for producing a diene polymer rubber, which comprises reacting an aminoketone with at least one compound selected from the group consisting of a thioaldehyde and a thioaminoketone corresponding thereto.