Process for Producing Blends of Syndiotactic, 1,2-Polybutadiene and Rubbery Elastomers

Abstract

Blends of syndiotactic 1,2-polybutadiene and rubbery elastomers are prepared by a process that comprises polymerizing 1,3-butadiene monomer into syndiotactic 1,2-polybutadiene within a rubber cement of an elastomeric terpolymer by using a chromium-based, molybdenum-based, or iron-based catalyst composition. Polymer composition comprising the blend with improved properties is also provided.

1 - 18 . (canceled) 
     
     
         19 . A method for making a polymeric composition comprising:
 mixing a rubber cement and 1,3-butadiene monomer, wherein the rubber cement comprises an elastomeric terpolymer polymerized from ethylene, at least one α.-olefin monomer, and at least one diene monomer;   polymerizing the 1,3-butadiene monomer into syndiotactic 1,2-polybutadiene within the rubber cement by using a catalyst composition that is formed by combining (a) a chromium-containing compound, (b) a hydrogen phosphite, and (c) an organomagnesium compound or (a) a molbydenum-containing compound or an iron-containing compound, (b) a hydrogen phosphite, and (c) an organoaluminum compound;   forming the composition into a tire sidewall.   
     
     
         20 . The method of  claim 19 , wherein the catalyst composition is added to the mixture of rubber cement and 1,3-butadiene monomer such that the chromium-containing compound, the molybdenum-containing compound, or the iron-containing compound is present in an amount of about 0.01 to about 2 mmol per 100 g of 1,3-butadiene. 
     
     
         21 . The method of  claim 19 , wherein the syndiotactic 1,2-polybutadiene has a melting temperature of from about 70° C. to about 210° C. 
     
     
         22 . The method of  claim 19 , wherein the mixture of syndiotactic 1,2-polybutadiene and elastomeric terpolymer comprises from about 3 percent to about 12 percent by weight of syndiotactic 1,2-polybutadiene. 
     
     
         23 . The method of  claim 19 , wherein a test sheet of the composition has a cut growth rate of 45 Dc/Dn (nm/cycle) and below at 50° C. 
     
     
         24 . The method of  claim 19 , wherein the α-olefin monomer is propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, or a combination thereof. 
     
     
         25 . The method of  claim 19 , wherein the diene monomer is 5-ethylidene-2-norbornene, 1,4-hexadiene, 5-methylene-2-norbornene, 1,6-octadiene, 5-methyl-1,4-hexadiene, 3,7-methyl-1,6-octadiene, 1,3-cyclopentadiene, 1,4-cyclohexadiene, dicyclopentadiene, 5-vinyl-2-norbornene, or a combination thereof. 
     
     
         26 . The method of  claim 19 , wherein said catalyst composition is added to the mixture of rubber cement and 1,3-butadiene monomer such that the chromium-containing compound, the molybdenum-containing compound, or the iron-containing compound is present in an amount of about 0.01 to about 2 mmol per 100 g of 1,3-butadiene. 
     
     
         27 . The method of  claim 19 , wherein the elastomeric terpolymer is ethylene-propylene-diene terpolymer. 
     
     
         28 . A tire sidewall comprising:
 a polymeric component including an elastomeric terpolymer polymerized from ethylene, at least one α.-olefin monomer, and at least one diene monomer; and   syndiotactic 1,2-polybutadiene.   
     
     
         29 . The tire sidewall of  claim 28 , wherein the α-olefin monomer is propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, or a combination thereof. 
     
     
         32 . The tire sidewall of  claim 28 , wherein the syndiotactic 1,2-polybutadiene has a melting temperature of from about 70° C. to about 210° C. 
     
     
         30 . The tire sidewall of  claim 28 , wherein the diene monomer is 5-ethylidene-2-norbornene, 1,4-hexadiene, 5-methylene-2-norbornene, 1,6-octadiene, 5-methyl-1,4-hexadiene, 3,7-methyl-1,6-octadiene, 1,3-cyclopentadiene, 1,4-cyclohexadiene, dicyclopentadiene, 5-vinyl-2-norbornene, or a combination thereof. 
     
     
         31 . The tire sidewall of  claim 28 , wherein the polymeric component comprises from about 3 percent to about 12 percent by weight of syndiotactic 1,2-polybutadiene. 
     
     
         32 . The tire sidewall of  claim 28 , wherein a test sheet of the tire sidewall has a cut growth rate of 45 Dc/Dn (nm/cycle) and below at 50° C. 
     
     
         33 . The tire sidewall of  claim 28 , wherein the elastomeric terpolymer is ethylene-propylene-diene terpolymer. 
     
     
         34 . The tire sidewall of  claim 28 , wherein the composition includes a chromium-, iron-, or molybdenum-containing compound, (b) a hydrogen phosphite, and (c) an organomagnesium or organoaluminum compound. 
     
     
         35 . The tire sidewall of  claim 28 , wherein the syndiotactic 1,2-polybutadiene is catalyzed with a combination of (a) a chromium-containing compound, (b) a hydrogen phosphite, and (c) an organomagnesium compound or (a) a molbydenum-containing compound or an iron-containing compound, (b) a hydrogen phosphite, and (c) an organoaluminum compound 
     
     
         36 . The tire sidewall  claim 28 , further comprising cis-polybutadiene. 
     
     
         37 . The tire sidewall of  claim 28 , further comprising natural rubber. 
     
     
         38 . The method of  claim 19 , further comprising mixing in an additional elastomer selected from the group consisting of: cis-polybutadiene, natural rubber, and mixtures thereof.