Process for producing conjugated diolefinic polymers
This invention relates to a process for producing conjugated diolefinic polymers. More particularly, it relates to a process for producing conjugated diolefinic homopolymers or copolymers excellent in green strength (tensile strength of the unvulcanized rubber) and processability of the unvulcanized compound and also in physical properties of the vulcanizate, which is characterized by adding water and/or an alcohol to the reaction system in polymerizing conjugated diolefins or copolymerizing conjugated diolefins with vinyl aromatic hydrocarbons with an alfin catalyst in the presence of (A) an unsaturated halohydrocarbon, (B) a halogenated aromatic compound, (C) an ether, a polyether or an acetal or (D) a tertiary amine, as the molecular weight regulator. 
     It has been well known that a polymer obtained by contacting a conjugated diolefin or a mixture of a conjugated diolefin and a vinyl aromatic hydrocarbon with an alfin catalyst (hereinafter such a polymer is referred to as alfin rubber) is a synthetic rubber excellent in abrasion resistance, felxural strength, and tensile strength when vulcanized and particularly excellent in green strength, as not seen in other synthetic rubbers. Difficulties encountered in processing the alfin rubber, owing to its extremely high molecular weight, are being eliminated by the discovery of various molecular weight regulators. 
     The molecular weight regulators are divided into two broad classes, one being hydrocarbon type and the other being compounds containing halogen, oxygen or nitrogen atoms. Effective molecular weight regulators of the hydrocarbon type are dihydro aromatic hydrocarbons (Japanese Patent Publication No. 15,034/62) and 1,4-dienes (U.S. Pat. No. 3,518,238). Regulators containing halogen, oxygen, or nitrogen atoms include unsaturated halohydrocarbons (U.S. Pat. No. 3,953,409), aromatic halogenated compounds (Belgian Pat. No. 706,516), ethers and acetals (U.S. Pat. No. 2,841,574), polyethers (Japanese Patent Publication No. 36,517/70) and tertiary amines (U.S. Pat. No. 2,841,574). 
     Of the above molecular weight regulators, those of the hydrocarbon type have an advantage of producing a polymer of a high trans-1,4 content characteristic of the alfin rubber without causing any change in microstructure of the polymer, and the resulting alfin rubber is characterized by a high green strength. The alfin rubber thus obtained, however, shows disadvantages in processing such as, for example, an extremely high rolling temperature. On the other hand, the alfin rubber formed by using regulators containing halogen, oxygen or nitrogen atoms in characterized in that it has excellent processability and can be processed by substantially the same procedures as used in processing customary generalpurpose rubbers. However, the use of said regulator results in a change in microstructure of the alfin rubber obtained, that is to say, the trans-1,4 content is reduced and the vinyl content is increased. Further, the green strength of the polymer obtained is low, whereby the feature as alfin rubber is weakened. 
     The present inventors have made various studies to overcome the disadvantages exhibited by the latter class of molecular weight regulators and, as a result, have found that when water and/or an alcohol is present in the above reaction system, the excessive decrease in molecular weight (or Mooney viscosity) is prevented to impart an adequate molecular weight to the resulting polymer, and the trans-1,4 content of the polymer is increased, whereby a polymer excellent in all of the green strength, processability, and physical properties of the vulcanizate is obtained. 
     An object of this invention is to provide a process for producing an alfin rubber which is excellent in green strength, processability and the physical properties of vulcanizate. 
     Other objects and advantages of this invention will become apparent from the following description. 
     According to this invention, there is provided a process for producing a conjugated diolefinic polymer by polymerizing at least one conjugated diolefin or copolymerizing at least one conjugated diolefin with at least one vinyl aromatic hydrocarbon in a hydrocarbon solvent in the presence of an alfin catalyst and at least one molecular weight regulator selected from the group consisting of (A) unsaturated halohydrocarbons represented by the general formula, RCX ═ CYZ, wherein R represents hydrogen, an alkyl group having 1 to 7 carbon atoms, a vinyl group, a phenyl groups, a substituted phenyl group, or a halogen atom and X, Y and Z represent independently a hydrogen or halogen atom, at least one of said R, X, Y and Z being a halogen atom, (B) halogenated aromatic hydrocarbons, (C) ethers, polyethers, and acetals, and (D) tertiary amines and, if necessary, a dihydro aromatic hydrocarbon, characterized in that said polymerization or copolymerization is effected in the presence of 0.03 to 0.9 mole of water and/or an alcohol per mole of organosodium in said alfin catalyst. 
     The molecular weight regulators (A) to (D) used in this invention include the following examples: 
     (A) Examples of the unsaturated halohydrocarbons represented by the general formula RCX ═ CYZ are, for instance, vinyl chloride, vinyl bromide, vinyl iodide, vinyl fluoride, vinylidene chloride, vinylidene fluoride, isopropenyl chloride, trichloroethylene, 2-chloro-1-butene, α-chlorostyrene, chloroprene and the like, vinyl chloride and vinylidene chloride being particularly preferred. 
     (B) Examples of the halogenated aromatic hydrocarbons are, for instance, chlorobenzene, bromobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, o-chlorotoluene, α-chloronaphthalene and the like. 
     (C) Examples of the ethers, polyethers, and acetals are, for instance, diethyl ether, diisopropyl ether, ethyl butyl ether, methyl benzyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, 1,1-dimethoxyethane, and benzaldehyde dimethyl acetal. 
     (D) Examples of the tertiary amines are, for instance, diethylmethylamine, triethylamine, trimethylamine, triisopropylamine, dimethylpropylamine, dimethylaniline, and the like. 
     The amount of the molecular weight regulator to be used may be such as is sufficient to produce a polymer having a desired Mooney viscosity and may be varied depending on the type of regulator. The amount of the regulator used per 100 g of the monomer is usually 0.01 to 1,000 mM (millimoles) in the case of (A), 0.05 to 2,000 mM in the case of (B), 0.01 to 10,000 mM in the case of (C), and 0.02 to 10,000 mM in the case of (D). These regulators may be used alone or in admixture or in admixture with regulators of the hydrocarbon type. As the regulators of the hydrocarbon type, dihydro aromatic hydrocarbons are particularly preferred because the resultant polymer has excellent physical properties. The dihydro aromatic hydrocarbons include, for example, 1,4-dihydrobenzene, 1,2-dihydrobenzene, 1,4-dihydronaphthalene, 1,2-dihydronaphthalene, dihydrotoluene, dihydroxylene, dihydroanthracene, and the like. 
     Particularly preferable is a combination of an unsaturated halohydrocarbon (A) represented by the general formula RCX ═ CYZ, and a halogenated aromatic hydrocarbon (B), with a dihydro aromatic hydrocarbon. With the above combination no gel is formed and a polymer having a Mooney viscosity of about 30 to 70 is readily obtained in a yield as high as 90% or more. Moreover, as compared with conventional alfin rubbers, the polymer thus obtained is characterized by lower content of both ultrahigh molecular weight fraction and low molecular weight fraction, better processability, and better and well-balanced physical properties of vulcanizate, such as, for example, modulus of elasticity, tensile strength, and elongation. A further advantage of the above procedure is that the molecular weight regulating effect is constant throughout the initial, intermediate, and final stages of polymerization, so that the alfin rubber can be produced in a continuous manner. 
     According to this invention, in addition to the above-mentioned advantages, the use of water or an alcohol together with the molecular weight regulators enables a further improvement of the green strength and processability of the polymer as well as the physical properties of the vulcanizate. 
     The water and/or alcohol is added to the reaction system in such an amount that the effect can be obtained without causing hindrance of the polymerization, and it ranges from 0.03 to 0.9 mole, preferably from 0.05 to 0.6 mole, per mole of organosodium in the catalyst. If the amount is below 0.03 mole, the advantage of this invention cannot be sufficiently obtained, while if it exceeds 0.9 mole, polymerization is hindered. 
     The alcohol to be added to the reaction system is one represented by the general formula, R--OH, wherein R is a saturated or unsaturated aliphatic or alicyclic hydrocarbon radical having 1 to 20 carbon atoms. Examples of the alcohol are, for instance, methanol, ethanol, isopropanol, n-butanol, n-dodecyl alcohol, cyclohexyl alcohol, cyclooctyl alcohol, and the like. Of these, methanol, ethanol, isopropanol, and n-butanol are preferred, and particularly preferable are isopropanol and n-butanol. 
     Since water and/or alcohol is added to the reaction system in this invention, it is not necessary to use an anhydrous solvent, and it has an economical and an operational effect. Addition of the alcohol can also easily be carried out, because the alcohol used in this invention is easily soluble in the reaction medium. 
     Although the way of adding water and/or an alcohol to the reaction system is not critical, it is desirable to add water and/or an alcohol to the solvent prior to contacting the catalyst with a monomer or monomers. Alternatively, a suitable amount of the hydrocarbon solvent containing a large quantity of water and/or an alcohol may be added to the polymerization system, or a solvent containing a suitable amount of water and/or an alcohol may also be used. 
     A typical alfin catalyst used in this invention is a ternary mixture or a complex comprising allyl sodium, sodium isopropoxide and sodium chloride, formed by reacting in a hydrocarbon solvent with stirring, n-amyl chloride with a sodium dispersion and further reacting the resultant n-amyl sodium successively with isopropyl alcohol and propylene. 
     As known well (e.g. Leo Reich: &#34;Polymerization by Organometallic Compounds&#34;, pp. 402-430, 1966, Interscience Publishers), the allyl sodium may be replaced by benzyl sodium, xylyl sodium, pentenyl sodium, cymyl sodium, mesityl sodium, and the like. It is also possible to replace isopropoxide by 2-butoxide, 3-pentoxide, cyclopentoxide, cyclobutoxide, tert-butoxide, and the like. Further, other alkali metal salts such as potassium salts and lithium salts may be used in place of the sodium salts. Other alkyl halides such as n-butyl chloride may be used in place of n-amyl chloride. The conditions for the preparation of an alfin catalyst and the catalyst compositions may, of course, be freely varied according to the known techniques. 
     The monomers which can be polymerized according to this invention are conjugated dienes such as 1,3-butadiene, isoprene, piperylene, 2,3-dimethyl-1,3-butadiene, and the like. Two or more of these conjugated dienes may also be copolymerized. It is also possible to copolymerize these conjugated dienes with vinyl aromatic hydrocarbons such as styrene, divinylbenzene, α-methylstyrene, β-methylstyrene, 3-vinyltoluene, 1-vinylnaphthalene, 2-vinylnaphthalene, p-methoxystyrene, p-bromostyrene, and the like. 
     Polymerization according to this invention may be carried out in a batchwise or continuous manner according to knwon techniques by contacting the monomer or monomers with an alfin catalyst in a hydrocarbon solvent in the presence of a molecular weight regulator and other additives. The polymerization temperature may be varied in a wide range of from about -50° to 150° C, preferably from about -20 °to 80° C. Any reaction pressure sufficient to keep the reactant mixture in the liquid phase may be used. It is generally in the range of 1 to 5 atmospheres. It is desirable to carry out the polymerization under an atmosphere of an inactive gas such as argon, helium, or nitrogen. 
     The catalyst is used in an amount of about 0.1 to about 100 millimoles in terms of organosodium per 100 g of the monomer. The weight ratio of hydrocarbon solvent to monomer is roughly 1 : 1 to 100 : 1. 
     As the hydrocarbon solvent, there may be used aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, and partially hydrogenated aromatic hydrocarbons. Preferable solvents are n-pentane, isopentane, n-hexane, n-heptane, n-octane, and isooctane among the aliphatic hydrocarbons; cyclohexane and cyclooctane among the alicyclic hydrocarbons; benzene, toluene, and xylene among the aromatic hydrocarbons; and tetrahydronaphlthalene among the partially hydrogenated aromatic hydrocarbons. 
     When the polymerization has proceeded to a desired stage, the reaction is terminated by adding an excess of water, an alcohol, or other catalyst inactivating agents to the reaction mixture. The solvent is then removed in a customary manner to obtain the objective polymer or copolymer. Before the removal of the solvent, it is desirable to add an antioxidant such as phenyl-β-naphthylamine to the reaction mixture. 
     The invention is illustrated below in further detail with reference to Examples, which are merely by way of illustration and not by way of limitation. The alfin catalyst used in the Examples and Comparative Examples was prepared in the following manner: 
     Into a four-necked flask provided with a stirrer, a reflux condenser, a thermometer and an external cooling bath was charged 300 parts of dry n-hexane. To the flask was added 23 parts (1.0 gram atom) of finely divided sodium (2 μ in particle size), and the contents of the flask were cooled to -10° C. Thereafter, 53.3 parts (0.5 mole) of dry amyl chloride was added gradually with gentle stirring, while maintaining the reaction system at -10° C. After the completion of the addition, stirring was further continued for about one hour. Then 15 g (0.25 mole) of dry isopropyl alcohol was gradually added with stirring, and the stirring was continued for an additional 45 minutes. After an excess of dry propylene had been introduced into the reaction system, the reaction temperature was maintained at -10° C until the propylene began to reflux. Then, the temperature was gradually elevated until it finally reached 25° C. After the reaction system had been kept at this temperature for about 2 hours while being stirred, the excess propylene was removed from the system. To the resulting reaction mixture was added dry n-hexane to make a total volume of 800 ml. All the above procedures were carried out under a nitrogen atmosphere. 
     In the Examples and Comparative Examples, the intrinsic viscosity of the polymer was measured in toluene at 30° C by means of a Ubbelohde&#39;s viscometer. The microstructure of polybutadienes was determined by the infrared absorption spectrum method proposed by D. Morero  Chim. e Ind., 41, 758 (1959)!. The styrene content is a styrene-butadiene copolymer was determined from the absorbancy at 699 cm -1  in infrared absorption spectrum according to the base line method. 
     The Mooney viscosity of the polymer was measured in accordance with the testing method specified in Japanese Industrial Standard (JIS) K 6300under the following conditions: dies with square grooves; speed of rotor, 2 rpm; type of rotor, L (large size); warm-up time, 1 minute; running time of rotor, 4 minutes; temperature of test, 100° C. Accordingly, the viscosity value was given under the designation of ML  1+4  (100° C). 
     The water content in the polymerization system was determined by means of Karl Fischer&#39;s apparatus for measuring water content. 
     COMPARATIVE EXAMPLE 1 
     Into a 5-liter autoclave, after the air therein has been thoroughly replaced by high-purity nitrogen, were introduced 2,250 g of dry cyclohexane, 41 millimoles of 1,4-dihydronaphthalene, and 25 g of styrene through an inlet at the top of the autoclave. The autoclave was closed and the stirring was started. Immediately thereafter, 225 g of liquid butadiene was introduced under pressure into the autoclave through a rubber packing at the bottom. After the temperature had been adjusted to 40° C, 51 ml of an alfin catalyst (containing 0.3 millimole of allyl sodium in 1 ml) was introduced under pressure into the autoclave through the rubber packing at the bottom and the reaction was allowed to proceed for 3 hours with stirring. On analysis, the reaction mixture was found to contain 0.024 mole of water per mole of allyl sodium in the catalyst, although no water had been intentionally added. After the completion of the reaction, the contents of the autoclave were withdrawn from the bottom into another vessel. After the addition of an antioxidant, the solvent was removed by steam distillation to obtain a solid polymer in the form of white bread crumbs. 
     The above solid polymer was washed with water and dried at 40° C under reduced pressure for 2 days. The yield of the polymer thus obtained was 99 %, and the polymer had the following microstructure: 65% of trans-1,4 configuration; 32% of vinyl configuration; and 3% of cis-1,4 configuration. It contained 10% of combined styrene and had an intrinsic viscosity  η! of 2.62 dl/g and ML 1+4  (100° C) of 50. These data are shown in Run No. 1 in Table 1. 
     The same procedure as above was repeated, except that the water content in the reaction system was varied by using, as a part of the solvent, cyclohexane saturated with water to obtain the results shown in Run No. 2 in Table 1. 
     
                                           Table 1                                 
__________________________________________________________________________
                             Intrinsic                                    
   Water*              Combined                                           
                             viscosity                                    
Run                                                                       
   content                                                                
       Yield                                                              
           Microstructure (%)                                             
                       styrene                                            
                              η!                                      
No.                                                                       
   (mole)                                                                 
       (%) Trans                                                          
               Vinyl                                                      
                   Cis (%)   (dl/g)                                       
                                  ML.sub.1+4 (100° C)              
__________________________________________________________________________
1  0.024                                                                  
       99  65  32  3   10    2.62 50                                      
2  0.221                                                                  
       96  66  31  3   10    2.66 53                                      
__________________________________________________________________________
 Note: *Water content is the amount of water contained in the reaction    
 mixture, in moles per mole of allyl sodium in the catalyst (the same     
 applies hereinafter).                                                    
 
    
    
    
     EXAMPLE 1 
     The same procedure as in Comparative Example 1 was repeated, except that 7 ml of vinyl chloride was used in place of the 1,4-dihydronaphthalene and the water content in the reaction system was varied by using, as a part of the solvent, cyclohexane saturated with water. The results obtained were as shown in Table 2. 
     
                                           Table 2                                 
__________________________________________________________________________
    Water               Combined                                          
Run content                                                               
        Yield                                                             
            Microstructure (%)                                            
                        styrene                                           
                               η!                                     
No. (mole)                                                                
        (%) Trans                                                         
                Vinyl                                                     
                     Cis                                                  
                        (%)   (dl/g)                                      
                                  ML.sub.1+4 (100° C)              
__________________________________________________________________________
3   0.025                                                                 
        98  53  44   3  10    2.39                                        
                                  44                                      
(cont-                                                                    
rol)                                                                      
4   0.132                                                                 
        98  56  40   4  10    2.48                                        
                                  46                                      
5   0.200                                                                 
        95  58  39   3  10    2.50                                        
                                  46.5                                    
6   0.376                                                                 
        93  63  34   3  11    2.62                                        
                                  50                                      
7   0.520                                                                 
        86  65  32   3  11    2.67                                        
                                  52                                      
__________________________________________________________________________
 
    
     It is seen from Table 2 that with an increase in water content, the trans-1,4 content of the resulting polymer is increased. 
     The polymers shown in Tables 1 and 2 were compounded according to the recipe shown in Table 3 on a 6-inch open roll and the green strength of the resulting compound was measured. After having been press-cured at 145° C for 40 minutes, the physical properties of the resulting vulcanizate were measured. The results obtained were as shown in Table 4. 
     
                       Table 3                                                     
______________________________________                                    
Ingredient           Parts by weight                                      
______________________________________                                    
Polymer              100                                                  
HAF carbon black     50                                                   
Aromatic process oil 5                                                    
Zinc oxide           5                                                    
Stearic acid         3                                                    
Accelerator (CZ)*    1.5                                                  
Sulfur               2                                                    
______________________________________                                    
 Note:- *CZ: n-cyclohexyl-benzothiazyl-sulfenamide                        
 
    
     
                                           Table 4                                 
__________________________________________________________________________
Run No.               1  2  3  4  5  6 7                                  
__________________________________________________________________________
Unvul-                                                                    
     Mooney viscosity, ML.sub.1+4 (100° C)                         
                      50 53 44 46   46.5                                  
                                     50 52                                
canized                                                                   
rubber                                                                    
     Softening temperature*, ° C                                   
                      82 90 53 55 54 58 59                                
     Compounded rubber:                                                   
     Green strength, kg/cm.sup.2                                          
                      29 32  7 15 18 21 23                                
     300 % Modulus, kg/cm.sup.2                                           
                      65 66 60 62 62 66 68                                
Vulca-                                                                    
     Tensile strength, kg/cm.sup.2                                        
                      224                                                 
                         230                                              
                            200                                           
                               205                                        
                                  210                                     
                                     221                                  
                                        239                               
nizate                                                                    
     Elongation, %    560                                                 
                         550                                              
                            620                                           
                               600                                        
                                  580                                     
                                     540                                  
                                        510                               
     Hardness (JIS A) 53 54 55 56 56 58 59                                
Remarks               Control  Present invention                          
__________________________________________________________________________
 Note:- *&#34;Softening temperature&#34; is the temperature of rubber at which 100
 g of unvulcanized rubber is uniformly banded on the roll (roll clearance:
 1.0 mm; guide distance: 100 mm) and cutting with a knife becomes possible
                                                                          
 
    
     It is seen from Table 4 that with an increase of the water content in the polymerization system in which vinyl chloride is used as a molecular weight regulator, the green strength of the polymer and the physical properties of the vulcanizate are increased, while the good processability is retained. Therefore, the rubber according to this invention is found excellent in processability, green strength, and even the physical properties of vulcanizate. 
     EXAMPLE 2 
     The same procedure as in Example 1 was repeated, except that 20 millimoles of diethylene glycol diethyl ether was substituted for the vinyl chloride. The results obtained were as shown in Table 5. 
     
                                           Table 5                                 
__________________________________________________________________________
    Water               Combined                                          
Run content                                                               
        Yield                                                             
            Microstructure (%)                                            
                        styrene                                           
                               η!                                     
No. (mole)                                                                
        (%) Trans                                                         
                Vinyl                                                     
                     Cis                                                  
                        (%)   (dl/g)                                      
                                  ML.sub.1+4 (100° C)              
__________________________________________________________________________
 8  0.021                                                                 
        99  40  57   3  10    2.00                                        
                                  32                                      
(cont-                                                                    
rol)                                                                      
 9  0.114                                                                 
        99  51  45   4  10    2.11                                        
                                  36                                      
10  0.210                                                                 
        96  54  42   4  10    2.17                                        
                                  37.5                                    
11  0.510                                                                 
        90  61  36   3  11    2.30                                        
                                  42                                      
__________________________________________________________________________
 
    
     Physical properties showed similar tendencies to those in Example 1. 
     EXAMPLE 3 
     The same procedure as in Example 1 was repeated, except that 4 millimoles of vinyl chloride, 7 millimoles of o-dichlorobenzene, and 8 millimoles of 1,4-dihydro-naphthalene were substituted for the 7 millimoles of vinyl chloride. The results obtained were as shown in Table 6. 
     
                                           Table 6                                 
__________________________________________________________________________
    Water               Combined                                          
Run content                                                               
        Yield                                                             
            Microstructure (%)                                            
                        styrene                                           
                               η!                                     
No. (mole)                                                                
        (%) Trans                                                         
                Vinyl                                                     
                     Cis                                                  
                        (%)   (dl/g)                                      
                                  ML.sub.1+4 (100° C)              
__________________________________________________________________________
12  0.024                                                                 
        99  51  46   3  10    2.22                                        
                                  40                                      
(cont-                                                                    
rol)                                                                      
13  0.150                                                                 
        93  54  43   3  10    2.29                                        
                                  43                                      
14  0.207                                                                 
        95  57  40   3  10    2.38                                        
                                  45                                      
15  0.396                                                                 
        89  62  34   4  11    2.41                                        
                                  45                                      
__________________________________________________________________________
 
    
     The polymers shown in Table 6 were compounded according to the recipe given in Table 3 and cured in the same manner as in Example 1 . The green strength and the physical properties of vulcanizate were measured to obtain the results as shown in Table 7. 
     
                       Table 7                                                     
______________________________________                                    
Run No.            12       13     14   15                                
______________________________________                                    
Unvul- Mooney viscosity,                                                  
                       40       43   45   45                              
canized                                                                   
       ML.sub.1+4 (100° C)                                         
rubber Softening temperature,                                             
                       55       55   57   56                              
       ° C                                                         
       Compounded rubber:                                                 
       Green strength, kg/cm.sup.2                                        
                       16       28   32   36                              
       300 % Modulus, kg/cm.sup.2                                         
                       85       95   95   97                              
Vulca- Tensile strength, kg/cm.sup.2                                      
                       211      220  240  243                             
nizate Elongation, %   530      550  570  570                             
       Hardness (JIS A)                                                   
                       58       60   59   60                              
Remarks            Control  Present invention                             
______________________________________                                    
 
    
     It is seen from Table 7 that as in Example 1, with an increase of the water content in the polymerization system, the green strength of the polymer and the physical properties of the vulcanizate are increased, while the good processability is retained. 
     EXAMPLE 4 
     The same procedure as in Example 3 was repeated, except that 250 g of butadiene was used as the monomer in place of the 25 g of styrene and 225 g of butadiene. The results obtained were as shown in Table 8. 
     
                       Table 8                                                     
______________________________________                                    
      Water                         η!                                
Run   content Yield   Microstructure (%)                                  
                                   (dl/ ML.sub.1+4                        
No.   (mole)  (%)     Trans Vinyl Cis  g)   (100° C)               
______________________________________                                    
16    0.021   99      53    44    3    2.28 43                            
(cont-                                                                    
rol)                                                                      
17    0.158   96      57    39    4    2.34 46                            
18    0.242   93      59    38    3    2.39 47                            
19    0.461   85      63    34    3    2.46 49                            
______________________________________                                    
 
    
     Physical properties showed similar tendencies to those in Example 3. 
     EXAMPLE 5 
     The same procedure as in Example 1 was repeated, except that 10 millimoles of 1,4-dihydronaphalene and 15 millimoles of trimethylamine were substituted for the 7 millimoles of vinyl chloride. The results obtained were as shown in Table 9. 
     
                                           Table 9                                 
__________________________________________________________________________
    Water               Combined                                          
Run content                                                               
        Yield                                                             
            Microstructure (%)                                            
                        styrene                                           
                               η!                                     
No. (mole)                                                                
        (%) Trans                                                         
                Vinyl                                                     
                    Cis (%)   (dl/g)                                      
                                  ML.sub.1+4 (100° C)              
__________________________________________________________________________
20  0.027                                                                 
        92  49  47  4   10    2.36                                        
                                  45.5                                    
(cont-                                                                    
rol)                                                                      
21  0.138                                                                 
        91  53  44  3   11    2.41                                        
                                  45                                      
22  0.287                                                                 
        87  55  43  2   11    2.44                                        
                                  47                                      
23  0.509                                                                 
        82  59  38  3   12    2.50                                        
                                  47.5                                    
__________________________________________________________________________
 
    
     Physical properties showed similar tendencies to those in Example 1. 
     EXAMPLE 6 
     The same procedure as in Example 1 was repeated, except that 5 millimoles of vinyl chloride and 9 millimoles of o-dichlorobenzene were substituted for the 7 millimoles of vinyl chloride, to obtain the resutls shown in Table 10. 
     
                                           Table 10                                
__________________________________________________________________________
    Water               Combined                                          
Run content                                                               
        Yield                                                             
            Microstructure (%)                                            
                        styrene                                           
                               η!                                     
No. (mole)                                                                
        (%) Trans                                                         
                Vinyl                                                     
                    Cis (%)   (dl/g)                                      
                                  ML.sub.1+4 (100° C)              
__________________________________________________________________________
24  0.020                                                                 
        97  50  46  4   10    2.40                                        
                                  45                                      
(Cont-                                                                    
rol)                                                                      
25  0.146                                                                 
        98  54  43  3   10    2.51                                        
                                  47                                      
26  0.292                                                                 
        93  58  39  3   11    2.58                                        
                                  49                                      
27  0.513                                                                 
        87  62  35  3   11    2.60                                        
                                  49.5                                    
__________________________________________________________________________
 
    
     Physical properties showed similar tendencies to those in Example 1. 
     EXAMPLE 7 
     The same procedure as in Example 1, except that 4 millimoles of vinyl chloride and 8 millimoles of diethylene glycol diethyl ether were substituted for the 7 millimoles of vinyl chloride, to obtain the results shown in Table 11. 
     
                                           Table 11                                
__________________________________________________________________________
    Water               Combined                                          
Run content                                                               
        Yield                                                             
            Microstructure (%)                                            
                        styrene                                           
                               η!                                     
No. (mole)                                                                
        (%) Trans                                                         
                Vinyl                                                     
                    Cis (%)   (dl/g)                                      
                                  ML.sub.1+4 (100° C)              
__________________________________________________________________________
28  0.018                                                                 
        99  48  49  3   10    2.16                                        
                                  37                                      
(cont-                                                                    
rol)                                                                      
29  0.120                                                                 
        97  54  43  3   10    2.23                                        
                                  40                                      
30  0.283                                                                 
        94  58  38  4   10    2.28                                        
                                  42                                      
31  0.476                                                                 
        89  63  34  3   11    2.30                                        
                                  43                                      
__________________________________________________________________________
 
    
     Physical properties showed similar tendencies to those in Example 1. 
     EXAMPLE 8 
     Polymerization was carried out in the same manner as in Comparative Example 1, except that 7 ml of vinyl chloride was substituted for the 1,4-dihydronaphthalene and various alcohols were added in varying amounts to the polymerization system. The results obtained were as shown in Table 12. 
     
                                           Table 12                                
__________________________________________________________________________
Alcohol             Water                                                 
Run            Amount*                                                    
                    content                                               
                        Yield                                             
                            Microstructure (%)                            
                                        η!                            
No.  Name      (mole)                                                     
                    (mole)                                                
                        (%) Trans                                         
                                Vinyl                                     
                                    Cis                                   
                                       dl/g)                              
                                           ML.sub.1+4 (100°        
__________________________________________________________________________
                                           C)                             
3    --        --   0.025                                                 
                        98 53   44  3  2.39                               
                                           44                             
(control)                                                                 
32   Methyl alcohol                                                       
               0.033                                                      
                    0.021                                                 
                        96 57   40  3  2.46                               
                                           46                             
33   Methyl alcohol                                                       
               0.065                                                      
                    0.024                                                 
                        93 58   39  3  2.47                               
                                           46                             
34   Methyl alcohol                                                       
               0.196                                                      
                    0.019                                                 
                        87 61   35  4  2.50                               
                                           46.5                           
35   Methyl alcohol                                                       
               0.495                                                      
                    0.023                                                 
                        76 65   31  4  2.53                               
                                           48                             
36   Isopropyl alcohol                                                    
               0.033                                                      
                    0.021                                                 
                        97 56   41  3  2.42                               
                                           44.5                           
37   Isopropyl alcohol                                                    
               0.065                                                      
                    0.025                                                 
                        98 58   38  4  2.44                               
                                           45                             
38   Isopropyl alcohol                                                    
               0.196                                                      
                    0.021                                                 
                        93 59   38  3  2.49                               
                                           46                             
39   Isopropyl alcohol                                                    
               0.495                                                      
                    0.023                                                 
                        85 63   34  3  2.51                               
                                           47                             
40   n-Butyl alcohol                                                      
               0.033                                                      
                    0.020                                                 
                        99 56   41  3  2.43                               
                                           45                             
41   n-Butyl alcohol                                                      
               0.065                                                      
                    --**                                                  
                        97 57   40  3  2.43                               
                                           45                             
42   n-Butyl alcohol                                                      
               0.196                                                      
                    --**                                                  
                        95 59   38  3  2.46                               
                                            45.5                          
43   n-Butyl alcohol                                                      
               0.495                                                      
                    0.023                                                 
                        89 62   35  3  2.49                               
                                           47                             
44   Cyclohexyl alcohol                                                   
               0.033                                                      
                    0.021                                                 
                        96 57   40  3  2.45                               
                                           46                             
45   cyclohexyl alcohol                                                   
               0.065                                                      
                    0.023                                                 
                        95 58   39  3  2.48                               
                                           47                             
46   Cyclohexyl alcohol                                                   
               0.196                                                      
                    0.024                                                 
                        90 58   38  4  2.49                               
                                           46.5                           
47   Cyclohexyl alcohol                                                   
               0.495                                                      
                    0.023                                                 
                        77 62   34  4  2.52                               
                                           48                             
__________________________________________________________________________
 Note:- *The amount of the alcohol added was expressed in moles per mole o
 allyl sodium in the catalyst (the same applies hereinafter).             
 **Since the dehydration treatment of the reaction system was effected    
 thoroughly, water was not detected (less than 0.01 mole, if any).        
 
    
     It is seen from Table 12 that the trans-1,4 content of the polymer increases with an increase of the amount of the alcohol added. 
     EXAMPLE 9 
     The procedure of Example 8 was repeated, except that 20 millimoles of diethylene glycol diethyl ether was substituted for the vinyl chloride. The results obtained were as shown in Table 13. 
     
                                           Table 13                                
__________________________________________________________________________
Alcohol                                                                   
Run            Amount                                                     
                    Yield                                                 
                        Microstructure (%)                                
                                    η!                                
No.  Name      (mole)                                                     
                    (%) Trans                                             
                            Vinyl                                         
                                Cis                                       
                                   (dl/g)                                 
                                       ML.sub.1+4 (100° C)         
__________________________________________________________________________
8    --        --   99  40  57  3  2.00                                   
                                       32                                 
(control)                                                                 
48   Methyl alcohol                                                       
               0.065                                                      
                    92  47  50  3  2.09                                   
                                       34                                 
49   Isopropyl alcohol                                                    
               0.065                                                      
                    97  46  51  3  2.05                                   
                                       32                                 
50   Isopropyl alcohol                                                    
               0.196                                                      
                    94  52  44  4  2.11                                   
                                       36                                 
51   n-Butyl alcohol                                                      
               0.065                                                      
                    98  46  50  4  2.06                                   
                                       33                                 
52   n-Butyl alcohol                                                      
               0.196                                                      
                    93  51  46  3  2.09                                   
                                       33                                 
53   Cyclohexyl alcohol                                                   
               0.065                                                      
                    96  48  49  3  2.04                                   
                                       32                                 
__________________________________________________________________________
 Note: The water content in the reaction system was in the range of 0.018 
 to 0.025 mole per mole of allyl sodium.                                  
 
    
     EXAMPLE 10 
     The procedure of Example 8 was repeated, except that 4 millimoles of vinyl chloride, 7 millimoles of o-dichlorobenzene, and 8 millimoles of 1,4-dihydronaphthalene were substituted for the 7 millimoles of vinyl chloride. The results obtained were as shown in Table 14. 
     
                                           Table 14                                
__________________________________________________________________________
Alcohol                                                                   
Run            Amount                                                     
                    Yield                                                 
                        Microstructure (%)                                
                                    η!                                
No.  Name      (mole)                                                     
                    (%) Trans                                             
                            Vinyl                                         
                                Cis                                       
                                   (dl/g)                                 
                                       ML.sub.1+4 (100° C)         
__________________________________________________________________________
12   --        --   99  51  46  3  2.22                                   
                                       40                                 
(control)                                                                 
54   Methyl alcohol                                                       
               0.065                                                      
                    93  57  40  3  2.33                                   
                                       44                                 
55   Isopropyl alcohol                                                    
               0.065                                                      
                    99  55  42  3  2.28                                   
                                       43                                 
56   Isopropyl alcohol                                                    
               0.196                                                      
                    96  59  38  3  2.40                                   
                                       46                                 
57   n-Butyl alcohol                                                      
               0.065                                                      
                    98  56  41  3  2.27                                   
                                       43                                 
58   n-Butyl alcohol                                                      
               0.196                                                      
                    95  58  39  3  2.38                                   
                                       46                                 
59   Cyclohexyl alcohol                                                   
               0.065                                                      
                    98  57  40  3  2.26                                   
                                       42                                 
__________________________________________________________________________
 Note: The water content in the reaction system was in the range of 0.018 
 to 0.025 mole per mole of allyl sodium.                                  
 
    
     EXAMPLE 11 
     The procedure of Example 8 was repeated, except that 10 millimoles of 1,4-dihydronaphthalene and 15 millimoles of trimethylamine were substituted for the 7 millimoles of vinyl chloride. The results obtained were as shown in Table 15. 
     
                                           Table 15                                
__________________________________________________________________________
Alcohol                                                                   
Run            Amount                                                     
                    Yield                                                 
                        Microstructure (%)                                
                                    η!                                
No.  Name      (mole)                                                     
                    (%) Trans                                             
                            Vinyl                                         
                                Cis                                       
                                   (dl/g)                                 
                                       ML.sub.1+4 (100° C)         
__________________________________________________________________________
20   --        --   92  49  47  4  2.36                                   
                                        45.5                              
(control)                                                                 
60   Methyl alcohol                                                       
               0.065                                                      
                    87  54  43  3  2.42                                   
                                       47                                 
61   Isopropyl alcohol                                                    
               0.065                                                      
                    90  53  44  3  2.38                                   
                                       45                                 
62   Isopropyl alcohol                                                    
               0.196                                                      
                    86  58  38  4  2.50                                   
                                       48                                 
63   n-Butyl alcohol                                                      
               0.065                                                      
                    91  54  43  3  2.40                                   
                                       46                                 
64   n-Butyl alcohol                                                      
               0.196                                                      
                    84  57  40  3  2.51                                   
                                       47.5                               
65   Cyclohexyl alcohol                                                   
               0.065                                                      
                    89  55  42  3  2.44                                   
                                       47                                 
__________________________________________________________________________
 Note: The water content in the reaction system was in the range of 0.018 
 to 0.027 mole per mole of allyl sodium.                                  
 
    
     The tendency of the effect of alcohols was similar to that in Example 8. 
     EXAMPLE 12 
     The procedure of Example 10 was repeated, except that 250 g of butadiene was used as the monomer in place of the 25 g of styrene and 225 g of butadiene. The results obtained were as shown in Table 16. 
     
                                           Table 16                                
__________________________________________________________________________
Alcohol                                                                   
Run            Amount                                                     
                    Yield                                                 
                        Microstructure (%)                                
                                    η!                                
No.  Name      (mole)                                                     
                    (%) Trans                                             
                            Vinyl                                         
                                Cis                                       
                                   (dl/g)                                 
                                       ML.sub.1+4 (100° C)         
__________________________________________________________________________
16   --        --   99  53  44  3  2.28                                   
                                       43                                 
(control)                                                                 
66   Methyl alcohol                                                       
               0.065                                                      
                    94  58  39  3  2.40                                   
                                       47                                 
67   Isopropyl alcohol                                                    
               0.065                                                      
                    98  58  38  4  2.35                                   
                                       46                                 
68   Isopropyl alcohol                                                    
               0.196                                                      
                    93  63  34  3  2.46                                   
                                       49                                 
69   n-Butyl alcohol                                                      
               0.065                                                      
                    99  57  40  3  2.33                                   
                                       46                                 
70   n-Butyl alcohol                                                      
               0.195                                                      
                    91  61  35  4  2.42                                   
                                       48                                 
71   Cyclohexyl alcohol                                                   
               0.065                                                      
                    95  56  41  3  2.36                                   
                                       46                                 
__________________________________________________________________________
 Note: The water content in the reaction system was in the range of 0.018 
 to 0.025 mole per mole of allyl sodium.                                  
 
    
     The tendency of the effect of alcohols was similar to that in Example 8. 
     EXAMPLE 13 
     The polymers obtained in Comparative Example 1 and Examples 8 to 12 were compounded according to the recipe given in Table 17 on a 6-inch open roll and the green strength of each compound was measured. After the compounds had been press-cured at 145° C for 40 minutes, the physical properties of the resulting vulcanizates were measured. The results obtained were as shown in Table 18. 
     
         ______________________________________                                    
Ingredient           Parts by weight                                      
______________________________________                                    
Polymer              100                                                  
HAF carbon black     50                                                   
Aromatic process oil 5                                                    
Zinc oxide           5                                                    
Stearic acid         3                                                    
Accelerator CZ*      1.5                                                  
Sulfur               2                                                    
______________________________________                                    
 Note:-*CZ:n-cyclohexyl-benzothiazyl-sulfenamide                          
 
    
     
                                           Table 18                                
__________________________________________________________________________
Run No.              1  3  34  38 42  46  12 54 56 58 59                  
__________________________________________________________________________
Unvul-                                                                    
    Mooney viscosity, ML.sub.1+4 (100° C)                          
                     50 44 46.5                                           
                               46 45.5                                    
                                      46.5                                
                                          40 44 46 46 42                  
canized                                                                   
rubber                                                                    
    Softening temperature*, ° C                                    
                     82 53 55  54 54  54  55 57 56 57 57                  
    Compounded rubber                                                     
    Green strength, kg/cm.sup.2                                           
                     29  7 21  18 20  18  16 30 34 32 28                  
    300 % Modulus, kg/cm.sup.2                                            
                     65 60 67  62 63  62  85 95 97 95 93                  
Vulca-                                                                    
    Tensile strength, kg/cm.sup.2                                         
                     224                                                  
                        200                                               
                           219 208                                        
                                  210 211 211                             
                                             230                          
                                                242                       
                                                   236                    
                                                      226                 
nizate                                                                    
    Elongation, %    560                                                  
                        620                                               
                           530 570                                        
                                  580 570 530                             
                                             550                          
                                                570                       
                                                   560                    
                                                      560                 
    Hardness (JIS A) 53 55 57  56 56  56  58 59 60 60 59                  
Remarks              Control                                              
                           Present invention                              
                                          Con-                            
                                             Present invention            
                                          trol                            
__________________________________________________________________________
 Note:- *Softening temperature is the temperature of rubber at which 100 g
 of unvulcanized rubber is uniformly banded on the roll (roll clearance:  
 1.0 mm; guide distance: 100 mm) and cutting with a knife becomes possible
                                                                          
 
    
     It is seen from the results shown in Table 18 that with an increase of the amount of alcohols added to the polymerization system, the green strength of the polymer and the physical properties of the vulcanizate are increased, while the good processability is retained. Therefore, the rubber according to this invention is found excellent in processability, green strength, and even the physical properties of vulcanizate.