Thermoplastic polypropylene blends with mixtures of ethylene/butene and ethylene/octene copolymer elastomers

DETAILED DESCRIPTION Thermoplastic compositions formed of olefinic, polymer blends and which have superior physical properties and adherence for coating materials such as paints are disclosed.
These blends may be formed from various combinations of thermoplastic and elastomeric components.
The thermoplastic component can include a homopolymer of propylene having an isotactic index which is greater than about 0.
93 or a crystallinity which is greater than about 56%; a sequentially polymerized blend of a semi-crystalline polypropylene and an ethylene-propylene copolymer; or mixtures thereof.
The elastomeric component can include a copolymer of ethylene and a C.
sub.
3 to C.
sub.
8 olefin produced with a metallocene or Kaminsky catalyst and having a molecular weight distribution (Mw/Mn) of less than or equal to 3.
These catalysts are also called "single site" catalysts.
In this specification, the following definitions will be used to define certain components of these compositions: Thermoplastic Components Component (1A): homopolymers and random copolymers of propylene having an isotactic index of greater than about 0.
93, preferably greater than about 0.
96 or a crystallinity of greater than about 56%, preferably greater than about 65%.
These components also have a density of greater than about 0.
898 g/cc, preferably greater than about 0.
906 g/cc; Component (1B): a sequentially polymerized blend or "block" copolymer of polypropylene and a copolymer of ethylene with propylene or ethylene with another alpha-olefin; and Component (1C): a mixture of (1A) and (1B).
Elastomeric Components As noted above, any copolymer of ethylene and a C.
sub.
3 to C.
sub.
8 olefin produced with a metallocene or Kaminsky catalyst and having a molecular weight distribution (Mw/Mn) of less than or equal to 3 is contemplated for use as this component.
Specially preferred components are as follows: Component (2): copolymers of ethylene and butene ("EB") produced with metallocene, Kaminsky or "single site" catalysts and which have Mw/Mn of less than or equal to 3; Component (3): copolymers of ethylene and octene produced with metallocene, Kaminsky or "single site" catalysts and having Mw/Mn of less than or equal to 3; and A mixture of components (2) and (3)