Elastic blends comprising crystalline polymer and crystallizable polymers of propylene

Abstract

Improved thermoplastic polymer blend compositions comprising an isotactic polypropylene component and an alpha-olefin and propylene copolymer component, said copolymer comprising crystallizable alpha-olefin sequences. In a preferred embodiment, improved thermoplastic polymer blends are provided comprising from about 35% to about 85% isotactic polypropylene and from about 30% to about 70% of an ethylene and propylene copolymer, wherein said copolymer comprises isotactically crystallizable propylene sequences and is predominately propylene. The resultant blends manifest unexpected compatibility characteristics, increased tensile strength, and improved process characteristics, e.g., a single melting point.

1 - 65  (Canceled).  
     
     
         66 : A method of nucleating a propylene copolymer comprising about 65 to about 96 weight percent propylene and about 4 to about 35 weight percent ethylene, the method comprising contacting the propylene copolymer with about 1 to about 8 weight percent of a predominately crystalline branched polymeric nucleating agent.  
     
     
         67 : The method of  claim 66  in which the nucleating agent is a polyolefin and the nucleating agent is present in an amount of about 1 to about 8 weight percent, based on the total weight of the propylene copolymer.  
     
     
         68 : The method of  claim 67  in which the polyolefin is propylene homopolymer or copolymer comprising ethylene and propylene.  
     
     
         69 : A method of nucleating a propylene copolymer comprising at least about 88.4 weight percent of units derived from propylene, about 5.8 to about 11.6 weight percent of units derived from ethylene, the copolymer further characterized as having at least one of one of the following properties: (i) a DSC curve with a T me  that remains essentially the same and a T max  that decreases as the amount of comonomer in the copolymer is increased, and (ii) an X-ray diffraction pattern that reports more gamma-form crystals than a comparable copolymer prepared with a Ziegler-Natta (Z-N) catalyst, the method comprising contacting the propylene copolymer with about 1 to about 8 weight percent of a predominately crystalline branched polymeric nucleating agent.  
     
     
         70 : The method of  claim 69  in which the propylene copolymer is characterized further by at least one of the following properties: (i) a B-value of about 1.4 when the comonomer content of the copolymer is about 5.8 weight percent, (ii) a skewness index, S ix , of about −0.32.  
     
     
         71 : The method of  claim 70  in which the nucleating agent is a polyolefin and the nucleating agent is present in an amount of about 1 to about 8 weight percent based upon weight of the propylene copolymer.  
     
     
         72 : The method of  claim 71  in which the polyolefin is propylene homopolymer or a copolymer comprising ethylene and propylene.  
     
     
         73 : An article comprising a nucleated polymer made by the method of  claim 66 .  
     
     
         74 - 104  (Canceled).  
     
     
         105 : The method of  claim 66  in which the propylene copolymer has a crystallinity of between 3% and 30%.  
     
     
         106 : The method of  claim 66  in which the propylene copolymer has a molecular weight distribution of about 2.1 to about 2.4.  
     
     
         107 : The method of  claim 68  in which the propylene copolymer has a crystallinity of between 3% and 30%.  
     
     
         108 : The method of  claim 68  in which the propylene copolymer has a molecular weight distribution of about 2.1 to about 2.4.  
     
     
         109 : The method of  claim 69  in which the propylene copolymer has a crystallinity of between 3% and 30%.  
     
     
         110 : The method of  claim 69  in which the propylene copolymer has a molecular weight distribution of about 2.1 to about 2.4.  
     
     
         111 - 122  (Canceled).