Olefin block copolymer composition with low tack

Abstract

Disclosed are oil-extended olefin block copolymer compositions with low, or no, tack. A unique comonomer content in the soft segment of the OBC in conjunction with the presence of a polyolefin provides the present oil-extended OBC composition with softness, low (or no) tack, and low (or no) oil-bleed.

1 . An oil-extended olefin block copolymer composition comprising:
 an olefin block copolymer comprising hard segments and soft segments, the soft segments comprising from about 9 mol % to less than 15 mol % comonomer content;   an oil;   one or more polyolefin;   a filler; and   the composition has the following properties after exposure to 70° C. for one week a tack force less than 0.1N; and   a Shore A hardness from about 50 to about 90.   
     
     
         2 . The composition of  claim 1  wherein the olefin block copolymer comprises an ethylene/octene multi-block copolymer comprising from about 5 wt % to about 30 wt % hard segments and from about 95 wt % to about 70 wt % soft segments. 
     
     
         3 . The composition of  claim 1  wherein the olefin block copolymer has a density from about 0.86 g/cc to about 0.88 g/cc. 
     
     
         4 . The composition of  claim 1  comprising from about 2 wt % to about 40 wt % olefin block copolymer; from about 20 wt % to about 50 wt % oil, from about 5 wt % to about 50 wt % polyolefin, and from about 20 wt % to about 40 wt % filler. 
     
     
         5 . The composition of  claim 1  wherein the polyolefin is selected from the group consisting of a polyethylene, a polypropylene, an ethylene-propylene-diene monomer rubber and combinations thereof. 
     
     
         6 . The composition of Claim lhaving a normalized oil bleed index of less than 20 after 3 weeks at 23 C. 
     
     
         7 . The composition of  claim 1  having a normalized oil bleed index of less than 50 after 3 weeks at 70 C. 
     
     
         8 . An oil-extended olefin block copolymer composition comprising:
 an olefin block copolymer comprising hard segments and soft segments, the soft segments comprising from about 9 mol % to less than 15 mol % comonomer content;   an oil;   one or more polyolefin;   a filler; and   the composition has the following properties after exposure to 70° C. for one week a normalized oil bleed index of less than 50; and   a Shore A hardness from about 50 to about 90.   
     
     
         9 . The composition of  claim 8  having a tack force from 0.0 N to less than 0.1N after exposure to 70 C for one week. 
     
     
         10 . The composition of  claim 8  wherein the polyolefin is a polyethylene with a density greater than 0.95 g/cc. 
     
     
         11 . The composition of  claim 8  comprising from about 2 wt % to about 30 wt % olefin block copolymer, from about 30 wt % to about 40 wt % oil, from about 5 wt % to about 25 wt % polyethylene, and from about 25 wt % to about 30 wt % filler. 
     
     
         12 . An oil-extended olefin block copolymer composition comprising:
 an olefin block copolymer comprising hard segments and soft segments, the soft segments comprising from about 9 mol % to less than 15 mol % comonomer content;   an oil;   a polyethylene;   a filler; and   the composition has the following properties after exposure to 70° C. for one week a tack force less than 0.020N; and   a Shore A hardness from about 40 to about 90.   
     
     
         13 . The composition of  claim 12  having a tack force from 0.0 N to less than 0.1N after exposure to 70 C for one week. 
     
     
         14 . The composition of  claim 12  wherein the polyolefin is a polyethylene with a density greater than 0.95 g/cc. 
     
     
         15 . The composition of  claim 12  having a compression set value from about 40% to about 70% as measured in accordance with ASTM D 395. 
     
     
         16 . The composition of  claim 12  further comprising an ethylene-propylene-diene monomer rubber. 
     
     
         17 . A molded oil-extended olefin block copolymer composition comprising:
 an olefin block copolymer comprising hard segments and soft segments, the soft segments comprising from about 9 mol % to less than 15 mol % comonomer content;   an oil;   one or more polyolefin;   a filler; and   the composition has the following properties after exposure to 70° C. for one week a tack force less than 0.1N; and   a Shore A hardness from about 50 to about 90   
       wherein the molded composition was prepared using a 0.41 μm surface roughness mold. 
     
     
         18 . The molded oil-extended composition of  claim 17  further comprising an ethylene-propylene-diene monomer rubber.