Oil gels of controlled distribution block copolymers and ester oils

Abstract

The present invention relates to oil gel compositions that include at least one non-aromatic ester oil and an anionic block copolymer of a mono alkenyl arene and a conjugated diene. The block copolymer is selectively hydrogenated and has mono alkenyl arene end blocks and a controlled distribution block of a mono alkenyl arene and a conjugated diene midblock. The ester oil is a non-aromatic, ester compound such as soybean oil, coconut oil, and other like compounds.

1 . An oil gel composition comprised of at least one hydrogenated block copolymer and a non-aromatic ester oil or mixture of non-aromatic ester oils, wherein said hydrogenated block copolymer has at least one polymer block A and at least one polymer block B, and wherein: 
 a. prior to hydrogenation each A block is a mono alkenyl arene homopolymer block and each B block is a controlled distribution copolymer block of at least one conjugated diene and at least one mono alkenyl arene;    b. subsequent to hydrogenation about 0-10% of the arene double bonds have been reduced, and at least about 90% of the conjugated diene double bonds have been reduced;    c. each A block has a number average molecular weight between about 3,000 and about 60,000 and each B block has a number average molecular weight between about 20,000 and about 300,000;    d. each B block comprises terminal regions adjacent to the A blocks that are rich in conjugated diene units and one or more regions not adjacent to the A blocks that are rich in mono alkenyl arene units;    e. the total amount of mono alkenyl arene in the hydrogenated block copolymer is about 20 percent weight to about 80 percent weight; and    f the weight percent of mono alkenyl arene in each B block is between about 10 percent and about 75 percent.    
     
     
         2 . The oil gel composition of  claim 1  wherein said mono alkenyl arene is styrene and said conjugated diene is selected from the group consisting of isoprene and butadiene.  
     
     
         3 . The oil gel composition of  claim 2  wherein said conjugated diene is butadiene, and wherein about 20 to about 80 mol percent of the condensed butadiene units in block B have 1,2-configuration.  
     
     
         4 . The oil gel composition of  claim 1  wherein said polymer block B has a mono alkenyl arene blockiness of less than about 40 mol percent.  
     
     
         5 . The oil gel composition of  claim 2  wherein the polymer is an ABA polymer and each block B has a center region with a minimum ratio of butadiene units to styrene units.  
     
     
         6 . The oil gel composition of  claim 2  wherein the weight percent of styrene in each B block is between about 10 percent and about 50 percent, and the styrene blockiness index of each block B is less than about 10 percent, said styrene blockiness index being defined to be the proportion of styrene units in the block B having two styrene neighbors on the polymer chain.  
     
     
         7 . The oil gel composition of  claim 1  wherein said hydrogenated block copolymer has a general configuration AB, ABA, (A-B) n ,(A-B) n A, (A-B) n ,X or mixtures thereof where n is an integer from 2 to about 30, and X is the coupling agent residue.  
     
     
         8 . The oil gel composition of  claim 7  wherein said hydrogenated block copolymer is a linear hydrogenated ABA styrene/butadiene block copolymer having a total molecular weight of about 80,000 to about 200,000.  
     
     
         9 . The oil gel composition of  claim 1  wherein said hydrogenated block polymer is a S-EB/S-S type polymer having a block molecular weight of 29,000-80,000/50,000-29,000, a % weight S of 57.5%, a % weight S in the EB/S block of 39% and a 1,2/1,4-butadiene ratio of 40/60.  
     
     
         10 . The oil gel composition of  claim 1  wherein said non-aromatic ester oil is an ester compound having one of the following formulas:  
       
         
           
           
               
               
           
         
       
       wherein R 1  and R 2  are the same or different and are hydrogen or a hydrocarbyl, said hydrocarbyl is substituted or unsubstituted, and n has any value from 1 to 8.  
     
     
         11 . The oil gel composition of  claim 1  wherein said non-aromatic ester oil is an ester compound having the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 1  comprises hydrogen or a substituted or unsubstituted hydrocarbyl and R 3  is a substituted or unsubstituted alkylene.  
     
     
         12 . The oil gel composition of  claim 1  wherein said non-aromatic ester oil is an ester compound having the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 4 , R 5  and R 6  individually are a substituted or unsubstituted alkylene, and R 7 , R 8  and R 9  individually include hydrogen or a substituted or unsubstituted hydrocarbyl.  
     
     
         13 . The oil gel composition of  claim 1  wherein said non-aromatic ester oil is a compound having the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 10 , R 11  and R 12  are the same or different fatty acid radicals containing from 8 to 22 carbon atoms.  
     
     
         14 . The oil composition of  claim 1  wherein said non-aromatic ester oil is soybean oil, coconut oil, eicosyl erucate or a C 12-15  alkyl octanoate.  
     
     
         15 . The oil gel composition of  claim 1  wherein the amount of non-aromatic ester oil is between about 250 to about 2000 parts by weight per 100 parts by weight of said at least one hydrogenated block copolymer.  
     
     
         16 . The oil gel composition of  claim 15  wherein the amount of non-aromatic ester oil is between about 400 to about 1000 parts by weight per 100 parts by weight of said at least one hydrogenated block copolymer.  
     
     
         17 . The oil gel composition of  claim 1  wherein said hydrogenated block polymer is a S-EB/S-S type polymer having a block molecular weight of 29,000-80,000/50,000-29,000, a % weight S of 57.5%, a % weight S in the EB/S block of 39% and a 1,2/1,4-butadiene ratio of 40/60; and said non-aromatic ester oil is one of soybean oil, coconut oil, eicosyl erucate or a C 12-15  alkyl octanoate.  
     
     
         18 . An article comprising at least the oil gel composition of  claim 1 .  
     
     
         19 . An article comprising at least the oil gel composition of  claim 17.