JPH0637523B2 - Method for producing diene polymer rubber - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a diene polymer rubber, and more specifically, a polyvinyl aroma having an active alkali metal and / or alkaline earth metal end. The present invention relates to a method for producing a diene polymer rubber, which comprises reacting a group compound-containing diene polymer with a tin compound and an organic compound having a specific atomic group.

(Prior art) In recent years, rolling friction resistance is small as rubber for automobile tire treads due to the demands of low fuel consumption and driving safety of automobiles (corresponding to high repulsive elasticity as a characteristic of rubber material), A rubber material having high wet skid resistance is strongly desired. However, these two characteristics are contradictory, and various polymer improved methods have been proposed in order to balance these two characteristics.

The present inventors have previously found that a diene polymer having an active alkali metal and / or alkaline earth metal terminal and a benzophenone having an amino group and / or a substituted amino group (Japanese Patent Laid-Open No. 2000-242242).
58-162604, JP-A-60-141706), in the molecule The above object can be achieved by reacting a compound having a bond (wherein M represents an oxygen or sulfur atom) (JP-A-60-137913) and introducing a specific atomic group into the polymer chain. Found out.

Further, a tin coupling which is improved in processability (rolling and extrusion) and cold flow properties, which are disadvantages of the diene polymer rubber modified with the above compound, and the introduction of the above atomic group are used in combination (JP-A-61-103903). , JP-A-61-103904).

(Problems to be Solved by the Invention) However, the diene polymer rubber obtained by using the tin coupling and the introduction of the atomic groups together has a good balance between rolling resistance (repulsive elasticity) and wet skid resistance, and further has good processability and storage stability. Although some improvement can be seen, the rebound resilience is inferior to the case without tin coupling, and the improvement of storage stability (cold flow) is not always satisfactory.

As a result of intensive studies to solve the above problems, the present inventors have found that it is effective to copolymerize a small amount of a polyvinyl aromatic compound.

For example, at the end of the diene polymer chain Or (Wherein M represents an oxygen or hydrogen atom, R'and R "represent a hydrogen atom or a substituent of the same or different hydrocarbons), but the repulsive elasticity is remarkably improved, but tin When the coupling chain is introduced, the processability and storability are improved with an increase in the coupling ratio (weight percentage of the tin-coupling polymer with respect to the total amount of the polymer), but the essential repulsive elasticity is lowered.

However, when a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl compound are polymerized, the reaction is carried out in the presence of a small amount of a polyvinyl aromatic compound, and when a tin coupling chain and the above-mentioned specific atomic group are introduced, the anti-repulsive elasticity is increased. The present invention has been completed based on the finding that processability and storability are improved with little or no reduction.

An object of the present invention is to provide an improved method for producing a diene polymer rubber which has an excellent balance between rolling resistance (repulsive elasticity) and wet skid resistance, and has good processability and storage properties.

(Means for Solving the Problems) An object of the present invention is to provide a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in a hydrocarbon solvent in an amount of 0.005 to 0.1 part by weight per 100 parts by weight of the total amount of the polyvinyl aroma. Polymerization in the presence of a group compound using an alkali metal and / or alkaline earth metal-based catalyst, the resulting diene polymer rubber having an alkali metal and / or alkaline earth metal terminal and (1) halogenation Tin compounds and
(2) In the molecule Selected from the group consisting of organic compounds having a bond (wherein M represents an oxygen or sulfur atom), aromatic aminoaldehydes, aromatic aminoketones and at least one compound of their corresponding thioaldehydes and thioaminoketones. This is accomplished by reacting at least one compound.

The object of the present invention is to polymerize a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl compound, copolymerize a small amount of a polyvinyl aromatic compound to introduce a branched structure into the polymer chain, and improve the fluidity of the polymer. It is considered that this can be achieved by reducing the number of active terminals per mole of the polymer chain and increasing the number of the specific atomic groups introduced at the same time. Therefore, it is preferable to adjust the number of tin couplings so that the number of the specific atomic groups introduced per mole of the polymer chain is substantially the same as that when the polyvinyl aromatic compound and the tin compound are not used.

The conjugated diene monomer used in the present invention includes 1,3-
It includes butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 1,3-hexadiene and the like. Aromatic vinyl monomers include styrene and α-
Methylstyrene, p-methylstyrene, vinyltoluene, vinylnaphthalene and the like are included. When copolymerizing a conjugated diene monomer and an aromatic vinyl monomer,
The content of aromatic vinyl monomer in both monomer mixtures is 50% by weight or less.

In order to achieve the object of the present invention, it is necessary to use the polyvinyl aromatic compound in an amount of 0.005 to 0.1 parts by weight, preferably 0.01 to 0.05 parts by weight, based on 100 parts by weight of all the monomers. When the amount of polyvinyl aromatic compound is less than 0.005 parts by weight of the total monomers, the storage property (cold flow) of the produced polymer rubber is not improved, and when it exceeds 0.1 parts by weight, roll and extrusion processability are poor.

As the polyvinyl aromatic compound, divinylbenzene,
1,2,4-trivinylbenzene, 1,3-divinylnaphthalene, 1,8-divinylnaphthalene, 1,3,5-trivinylnaphthalene, 2,4-divinylbiphenyl, 1,2-divinyl-3,
4-dimethylbenzene, 1,5,6-trivinyl-3,7-diethylnaphthalene, 1,3-divinyl-4,5,8-tributylnaphthalene, 2,2'-divinyl-4-ethyl-4'-propyl Biphenyl, and the like. Divinyl aromatic hydrocarbons having up to 26 carbon atoms are preferred, especially the o-, m- or p-divinyl benzene catalysts. Practically satisfactory is the commercially available divinyl benzene which is a mixture of these isomers.

As the alkali metal-based catalyst used in the present invention, an organolithium-based catalyst is particularly common, for example, methyllithium, ethyllithium, n-propyllithium, i-
Propyl lithium, n-butyl lithium, sec-butyl lithium, t-butyl lithium, octyl lithium, n
-Decyl lithium, phenyl lithium, 2-naphthyl lithium, 2-butyl-phenyl lithium, 4-phenyl-butyl lithium, cyclohexyl lithium, 4-cyclopentyl lithium, 1,4-dilithio-butene-2 and the like. However, the present invention is not limited to these.

Examples of alkaline earth metal-based catalysts include (1) JP-A-52-
48910 disclosed Ba tertiary alkoxide / dibutyl Mg complex, (2) with organic Li disclosed in JP-A-52-9090 [At least one R in the formula represents a methyl or cyclohexyl group, and the remaining R represents a C _1-6 alkyl group or the like,
a: b = 99.5 to 88: 0.5 to 12 (in molar ratio). ], (3) a complex initiator composed of Ba alcoholate or phenolate / organic Li or Mg / organic A disclosed in JP-A-56-112916, (4) JP-A-52-17591, 30543, 98077, Examples include those disclosed in JP-A-56-112916 and JP-A-57-98077. The amount of these catalysts used is usually 10
It is in the range of 0.2 to 20 millimoles per 0 gram. A polar compound such as an ether compound, an amine compound or a phosphine compound can be present as a vinylating agent when polymerizing a conjugated diene monomer or as a randomizer when copolymerizing a conjugated diene monomer and an aromatic vinyl monomer. The polymerization is usually carried out in the temperature range of -20 ° C to 150 ° C, but the temperature range of 40 ° C to 120 ° C is preferable. The polymerization can be carried out at either elevated temperature or constant temperature.

The hydrocarbon solvent used in the present invention is selected from aliphatic hydrocarbons, aromatic hydrocarbons and alicyclic hydrocarbons, and particularly propane having 2 to 12 carbon atoms, n-butane, i-
Butane, n-pentane, i-pentane, n-hexane,
Cyclohexane, propene, n-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 preferable. Further, these solvents may be used as a mixture of two or more kinds.

Thus, a diene polymer rubber having an alkali metal and / or alkaline earth metal terminal is obtained.

Then, a diene polymer rubber having this metal end
(1) tin halide compound and (2) in the molecule It is reacted with an organic compound having a bond (wherein M represents an oxygen atom or a sulfur atom), an aromatic aminoaldehyde, an aromatic aminoketone, and at least one compound selected from the corresponding thioaldehyde and thioketone.

The tin halide compound used in the present invention is usually referred to as a coupling agent, and is used for increasing the molecular weight of the polymer.

Specifically, methyltrichlorotin, dimethyldichlorotin, tetrachlorotin, dichlorotin, ethyltrichlorotin, diethyldichlorotin, tetrafluorotin, butyltrichlorotin, dibutyldichlorotin, octyltrichlorotin, dioctyldichlorotin, methylchloro. Tin, dimethyldibromotin, octyltribromotin, tetratin chloride, tetrabromotin, tetraiodotin, cyclohexyltrichlorotin, phenyltrichlorotin, 1,2-bis (trichlorostannyl) ethane, 1,2-bis (methyl Kurorosutaniru) ethane, 1,4-bis (trichloromethyl stannyl) butane, 1,4-bis (general formula R _a S _n X _b (wherein R, such as methyldichlorosilane stannyl) butane hydrocarbon residue, X is a halogen atom, a is an integer of 0 to 2, and b is an integer of 2 to 4). .

The amount of the tin halide compound used is usually in the range of 0.1 to 0.5 equivalent based on the halogen atom of the tin compound per mol of the activated diene polymer rubber having a metal terminal, and the high molecular weight depending on the amount of the tin compound. The proportion of polymerized polymer can be controlled. The amount of tin compound used is based on halogen atoms
If it is less than 0.1 equivalent, the processability and storability are poor, and if it is more than 0.5 equivalent, the impact resilience is poor. The high molecular weight reaction with the tin compound is carried out at 0 to 150 ° C. for 0.5 minutes to 20 hours.

In the molecule used in the present invention Organic compound having a bond (M is the same as above) [compound
(I)] and at least one compound selected from aromatic aminoaldehydes, aromatic aminoketones and their corresponding thioaldehydes and thioketones (compound (II)) are alkali metal at the terminal of diene polymer rubber molecule and / or Alternatively, it reacts with an alkaline earth metal and is introduced at the terminal of the rubber molecule as the above-mentioned specific atomic group.

Examples of compound (I) include N, N-diethylformamide, N,
Amides such as N-dimethylacetamide and N, N-dimethylbenzamide, ureas such as N, N′-dimethylurea,
ε-caprolactam, N-methyl-ε caprolactam,
Examples include lactams such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, and the compounds disclosed in JP-A-61-103904.

The compound (II) is an aromatic compound having 1 to 4 amino groups in the molecule. 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 4 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-butyl Phenoxazine, 3,7-diamino-10-acetylphenoxazine, acridone, N
-Methylacridone, 4-aminobenzaldehyde, 4
-Dimethylaminobenzaldehyde, 3,5-bis (dihexylamino) -benzaldehyde, 2,4,6-tris (diethylamino) benzaldehyde, 4-dicyclopentylaminobenzaldehyde, 4,5-bis (diethylamino) -1-naphthaldehyde, etc. , And their corresponding thioketones and thioaldehydes, but the compounds are not particularly limited as long as the compounds react with the metal at the polymer terminal. Particularly preferred are N, N-disubstituted amino compounds.

The compounds [I] and [II] are used in an amount of 0.5 to 0.9 mol per mol of the active diene polymer rubber having a metal terminal. If the amount of these compounds used is less than 0.5 mol, the impact resilience is poor, and if it is more than 0.9 mol, processability,
Poor storability. Although the reaction temperature and the reaction time can be selected within a wide range, it is generally from room temperature to 100 ° C for several seconds to several hours.

In the present invention, use of a diene polymer rubber having a polymer chain terminal of dienyl-the metal bond further enhances the effect of the present invention, and thus the use of the rubber is particularly desirable.

The reaction sequence of the metal-terminated diene polymer rubber with the tin halide compound and the compounds [I] and [II] may be arbitrary.
After the coupling reaction with the tin halide compound, the addition reaction with the compounds [I] and [II] is performed, on the contrary, the reaction with the tin compound is performed after the addition reaction, and the two reactions are simultaneously performed. Any of the three methods are acceptable. Of course, when the above two reactions are carried out in two steps, after the first step reaction,
It is necessary to control the amount of compound added in the first stage so that unreacted active polymer chains with the metal ends remain.

After completion of the reaction, the modified diene polymer rubber is separated from the reaction solution by using the coagulation method used in the production of rubber by ordinary solution polymerization such as addition of coagulant such as alcohol or steam coagulation as it is. . The solidification temperature is also not particularly limited. The crumb separated from the reaction system can also be dried by using a band dryer, an extrusion type dryer or the like used in the usual production of synthetic rubber, and the drying temperature is not particularly limited.

(Effect of the invention) The diene polymer rubber thus obtained has an excellent balance of rolling resistance and wet skid resistance,
It is very useful as a rubber material for a tire tread, which has good storability.

(Example) Hereinafter, the present invention will be described more specifically with reference to Examples. Parts and% in Examples and Comparative Examples are based on weight unless otherwise specified.

Example 1 A stainless steel polymerization reactor having an internal volume of 2 was washed and dried,
After substituting with dry nitrogen, 100 g of 1,3-butadiene,
18 g of styrene, 840 g of cyclohexane, tetramethylethylenediamine, divinylbenzene, and n-butyllithium (n-hexane solution) were added in the amounts shown in Table 1,
Polymerization was carried out at 60 ° C. for 2 hours while stirring the content. After the completion of the polymerization reaction, tin tetrachloride was added in the amount shown in Table 1, and 15
After reacting for minutes, the compounds shown in Table 1 were further added with n-
Butyllithium was added in an equimolar amount, and an addition reaction was performed for 15 minutes. After that, 5 m of methanol was added to stop the reaction, and the polymer solution was taken out into a 2,6-di-t-butyl-p-cresol (BHT) 1.5% methanol solution to coagulate the produced polymer, and then 60 ° C. And dried under reduced pressure for 24 hours.
The vinyl bond content and styrene content of the polymer thus obtained were measured by infrared spectroscopy [Hampton, Anal Chem,
21 , 923 (1949)]. The high molecular weight conversion 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 of gel permeation chromatography are as follows.

Column: Two Toyo Soda GMH-6 Temperature: 38 ° C Flow rate: 1.2 m / min In addition, the addition rate of the reaction substance is suitable for the reaction substance by attaching an ultraviolet absorption analyzer to the detection part of the gel permeation chromatography. It was calculated from the absorption intensity at different wavelengths and the molecular weight.

Polymer structure of polymer rubber and Mooney viscosity (ML
_{1 + 4} , 100 ° C) is shown in Table 1.

The obtained polymer was kneaded and mixed with each compounding agent in a Prabender type mixer having a capacity of 250 m according to the compounding recipe in Table 2 to obtain a rubber compounding composition. This thing 160 ℃
Was press-vulcanized for 25 minutes to prepare a test piece.

Table 2 Compounding formula Polymer rubber 100 parts by weight Zinc white NO.3 3〃 Stearic acid 1.5〃 Sulfur yellow 1.75〃 HAF carbon black 50〃 Aromatic process oil 5〃 N-cyclohexyl-2-benzothiazole sulfenamide 1.0〃 Rubber compound The processability of the composition was evaluated by the compound Mooney viscosity, roll winding property, and extrusion processability.

The roll wrapping property was judged by observing the state 1 minute after winding the compounded composition on a 6 inch roll having a temperature of 50 ° C. and a roll gap of 1.5 mm. The state in which the compound composition wrapped around the roll was tightly wrapped around the roll was "excellent", the state in which the composition was sometimes floated above the roll was "good", and the so-called bagging state in which it was not wrapped around the roll was "poor".

The extrudability was evaluated according to Method A described in ASTM D2230-78. The temperature of the barrel, the head, and the die were all 100 ° C., the rotation speed of the screw was 30 rpm, and the shape of the extrudate was evaluated by Rating System A of ASTM D2230-78. The total score of four evaluation items of shape is 16 ~
14 is "excellent", 13-11 is "good", and 10 or less is "poor"
And

The cold flow property was judged by the flow of No. 3 dumbbell described in JIS K-6301 punched out from a 2 mm sheet of polymer.

A 2 mm sheet of polymer was prepared by hot-pressing the polymer at 100 ° C. for 5 minutes, followed by water cooling for 30 minutes or more while maintaining the pressure state. One end of the dumbbell was fixed and suspended in an atmosphere of 23 ° C., and an index of cold flow property was obtained from the elongation of the dumbbell. The elongation was determined from the length of the marked line with a distance of 20 mm which was previously described in the center of the dumbbell. If the elongation after 300 minutes from hanging is less than 10%, it is "small", 10% or more 4
Less than 0% is "medium", and 40% or more is "large".

The impact resilience of the vulcanized rubber was measured at 50 ° C. using a Dunlop trypsometer. Wet skid resistance is 23 ° C using a Stanley portable skid tester, road surface (ASTM E-303-74, 3M outdoor type B,
Black, safety walk) was used for measurement.

The results are shown in Table 3.

From the results shown in Table 3, it is understood that the butadiene-styrene copolymer obtained by the method of the present invention has an excellent balance of rolling resistance (impact resilience) and wet skid resistance, and further has good processability and storability.

Further, the experiment was repeated under the same conditions except that the benzophenone compound of Experiment No. 1 was changed to the corresponding thiobenzophenone compound and the urea compound of Experiment No. 7 was changed to the corresponding thiourea compound, and the same results as Experiment Nos. 1 and 7 were obtained. It was

Claims (1)

[Claims] 1. A conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in a hydrocarbon solvent, in the presence of 0.005 to 0.1 part by weight of a polyvinyl aromatic compound per 100 parts by weight of the total amount of the alkali metal and / or Or a diene polymer rubber having an alkali metal and / or an alkaline earth metal terminal obtained by polymerizing using an alkaline earth metal-based catalyst, and (1) a tin halide compound and (2)
In the molecule Selected from the group consisting of organic compounds having a bond (wherein M represents an oxygen or sulfur atom), aromatic aminoaldehydes, aromatic aminoketones and at least one compound of their corresponding thioaldehydes and thioaminoketones. A method for producing a diene polymer rubber, which comprises reacting with at least one kind of compound.