Heterogeneous polymer blend and process of making the same

Abstract

A heterogeneous polymer blend comprises a continuous phase comprising a thermoplastic first polymer having a crystallinity of at least 30% and a dispersed phase comprising particles of a second polymer different from the first polymer dispersed in said continuous phase, the second polymer having a crystallinity of less than 20% and being at least partially cross-linked, and the average particle size of the particles of the second polymer being less than 1 micron.

1 . A heterogeneous polymer blend comprising: 
 (a) a continuous phase comprising a thermoplastic first polymer having a crystallinity of at least 30%; and    (b) a dispersed phase comprising particles of a second polymer different from the first polymer dispersed in said continuous phase, the second polymer having a crystallinity of less than 20% and being at least partially cross-linked, and the average particle size of the particles of the second polymer being less than 1 micron.    
     
     
         2 . The polymer blend of  claim 1  wherein said thermoplastic first polymer is a homopolymer of a C 2  to C 20  olefin.  
     
     
         3 . The polymer blend of  claim 1  wherein said thermoplastic first polymer is a copolymer of a C 2  to C 20  olefin with less than 15 wt % of at least one comonomer.  
     
     
         4 . The polymer blend of  claim 1  wherein said thermoplastic first polymer comprises a polymer of propylene.  
     
     
         5 . The polymer blend of  claim 1  wherein the second polymer is produced from a plurality of comonomers comprising at least one C 3  to C 20  olefin and at least one polyene.  
     
     
         6 . The polymer blend of  claim 5  wherein said at least one polyene has at least two polymerizable unsaturated groups.  
     
     
         7 . The polymer blend of  claim 5  wherein said plurality of comonomers comprise propylene and ethylene.  
     
     
         8 . The polymer blend of  claim 1  wherein the average particle size of the particles of the second polymer is between about 50 nanometers and about 0.5 microns.  
     
     
         9 . The polymer blend of  claim 1  wherein said dispersed phase comprises more than 50 wt % of the total heterogeneous polymer blend.  
     
     
         10 . A heterogeneous polymer blend comprising 
 (a) a continuous phase comprising a thermoplastic first polymer having a crystallinity of at least 30%; and    (b) a dispersed phase comprising particles of a second polymer different from the first polymer dispersed in said continuous phase, the second polymer having a crystallinity of less than 20% and being at least partially cross-linked, and the average particle size of the particles of the second polymer being less than 10 microns,    wherein said polymer blend is substantially free of processing oil.    
     
     
         11 . The polymer blend of  claim 10  wherein said thermoplastic first polymer is a homopolymer of a C 2  to C 20  olefin.  
     
     
         12 . The polymer blend of  claim 10  wherein said thermoplastic first polymer is a copolymer of a C 2  to C 20  olefin with less than 15 wt % of at least one comonomer.  
     
     
         13 . The polymer blend of  claim 10  wherein the second polymer is produced from a plurality of comonomers comprising at least one C 3  to C 20  olefin and at least one polyene.  
     
     
         14 . The polymer blend of  claim 10  wherein the average particle size of the particles of the second polymer is less than 1 micron.  
     
     
         15 . The polymer blend of  claim 10  wherein the average particle size of the particles of the second polymer is between about 50 nanometers and about 0.5 microns.  
     
     
         16 . A heterogeneous polymer blend comprising 
 (a) a continuous phase comprising a thermoplastic first polymer that is at least partially crystalline; and    (b) a dispersed phase comprising particles of a second polymer different from the first polymer dispersed in said continuous phase, wherein said dispersed phase comprises at least a fraction which is insoluble in xylene and which comprises less than 2,500 ppm of a curative.    
     
     
         17 . The polymer blend of  claim 16  wherein said fraction insoluble in xylene comprises less than 100 ppm of a curative.  
     
     
         18 . The polymer blend of  claim 16  wherein said fraction insoluble in xylene comprises at least is at least 4% of said dispersed phase.  
     
     
         19 . A process for producing a heterogeneous polymer blend comprising (a) a continuous phase comprising a thermoplastic first polymer that is at least partially crystalline; and (b) a dispersed phase comprising particles of a second polymer different from the first polymer dispersed in said continuous phase, the second polymer having a crystallinity less than that of the first polymer and being at least partially cross-linked, the process comprising: 
 (i) polymerizing at least one first monomer to produce a thermoplastic first polymer that is at least partially crystalline; and    (ii) contacting at least part of said first polymer with at least one second monomer and at least one polyene under conditions sufficient to polymerize said second monomer to produce said second polymer and simultaneously cross-link said second polymer such that the dispersed phase produced by said contacting (ii) comprises at least a fraction which is insoluble in xylene.    
     
     
         20 . The process of  claim 19  wherein said polymerizing (i) is conducted in the presence of a catalyst and said contacting (ii) is conducted in the presence of the same catalyst.  
     
     
         21 . The process of  claim 19  wherein said polymerizing (i) is conducted in the presence of a first catalyst and said contacting (ii) is conducted in the presence of a second catalyst different from the first catalyst.  
     
     
         22 . A process for producing a heterogeneous polymer blend, the process comprising: 
 (a) selecting a catalyst capable of polymerizing a C 2  to C 20  olefin to produce a first polymer having at least 30% crystallinity;    (b) contacting said catalyst with one or more C 2  to C 20  olefins at a temperature of at least 50° C. to produce a first polymer having at least 30% crystallinity;    (c) contacting said first polymer and said catalyst with at least one C 3  to C 20  olefin and at least one polyene under conditions sufficient to polymerize said at least one C 3  to C 20  olefin to produce a second polymer and simultaneously cross-link said second polymer, whereby the product of said contacting (c) is a heterogeneous polymer blend comprising a continuous phase of the first polymer having at least 30% crystallinity and a discontinuous phase of particles of said second polymer having an average particle size less than 10 microns, said second polymer being at least partially cross-linked and comprising at least 15 wt % of said C 3  to C 20  olefin and at least 0.0001 wt % of said polyene.    
     
     
         23 . The process of  claim 22  wherein the first polymer produced in said contacting (b) has at least 0.01% terminal unsaturation.  
     
     
         24 . The process of  claim 22  wherein said C 2  to C 20  olefin comprises propylene.  
     
     
         25 . The process of  claim 22  wherein said first polymer is contacted with ethylene together with said at least one C 3  to C 20  olefin and said at least one polyene in said contacting (c).  
     
     
         26 . The process of  claim 22  wherein said polyene has at least two polymerizable unsaturated groups.  
     
     
         27 . The process of  claim 22  wherein said catalyst selected in (a) is a single site catalyst comprising at least one catalyst component and at least one activator.  
     
     
         28 . The process of  claim 27  wherein said catalyst component is a bridged bis-indenyl metallocene catalyst having a substituent on one or both of the 2- and 4-positions on each indenyl ring.  
     
     
         29 . A process for producing a heterogeneous polymer blend, the process comprising: 
 (a) selecting a catalyst capable of polymerizing a C 2  to C 20  olefin to produce a first polymer having at least 30% crystallinity;    (b) contacting said catalyst with one or more C 2  to C 20  olefins at a temperature of at least 50° C. to produce a first polymer having at least 30% crystallinity;    (c) contacting said first polymer together with at least one C 3  to C 20  olefin and at least one polyene with a catalyst capable of polymerizing bulky monomers under conditions sufficient to polymerize said at least one C 3  to C 20  olefin to produce a second polymer and simultaneously cross-link said second polymer, whereby the product of said contacting (c) is a heterogeneous polymer blend comprising a continuous phase of the first polymer having at least 30% crystallinity and a discontinuous phase of particles of said second polymer having an average particle size less than 3 microns, said second polymer being at least partially cross-linked and comprising at least 15 wt % of said C 3  to C 20  olefin and at least 0.0001 wt % of said polyene.    
     
     
         30 . The process of  claim 29  wherein the first polymer produced in said contacting (b) has at least 0.1% terminal unsaturation.  
     
     
         31 . The process of  claim 29  wherein said C 2  to C 20  olefin comprises propylene.  
     
     
         32 . The process of  claim 29  wherein said first polymer is contacted with ethylene together with said at least one C 3  to C 20  olefin and said at least one polyene in said contacting (c).  
     
     
         33 . The process of  claim 29  wherein said polyene has at least two polymerizable unsaturated groups.  
     
     
         34 . The process of  claim 29  wherein the particles of said second polymer blend produced in step (c), prior to any subsequent curing step, have a melting temperature of at least 100° C.  
     
     
         35 . The process of  claim 29  wherein the catalyst selected in (a) is different from the catalyst employed in said contacting (c).