Plastic toughened plastics

DETAILED DESCRIPTION In certain embodiments of our invention, plastic toughened plastics including an iPP and an mPE are contemplated.
The plastic toughened plastics will generally be blends.
Theses plastic toughened plastics will exhibit a superior balance of tensile toughness and stiffness as well as enhanced elongation, as compared to a similar blend of iPP and Ziegler-Natta catalyzed PE.
The combination of iPP and mPE will be especially useful in molded parts, more particularly molded automotive interior trim parts.
Following is a detailed description of certain preferred combinations of iPP and mPE, their fabrication into useful articles and use of these articles.
Those skilled in the art will appreciate that numerous modifications to these preferred embodiments may be made without departing from the scope of our invention.
For example, while certain specific blends of iPP and mPE are exemplified, other blends are also contemplated.
Additionally, while automotive interior trim parts are discussed as uses for the inventive blends, other uses are also contemplated.
To the extent that this description is specific, it is solely for the purpose of illustrating certain preferred embodiments of the invention and should not be taken as limiting the present inventive concepts to these specific embodiments.
The tensile toughness as well as elongation will also be improved by the above referenced blends at low temperature, e.
g.
-10.
degree.
C.
, and the modulus maintained in an acceptable level.
Unblended iPP changes failure modes as the temperature drops.
At or near room temperature (23.
degree.
C.
) iPP fails in what is known as a crazing failure mode.
This mode is highly energy absorbing.
At low temperatures (.
ltoreq.
0.
degree.
C.
), the failure mode changes to brittle failure mode.
By contrast, polyethylenes exhibit a ductile-to-brittle transition failure mode at a temperature that is well below that of iPP, resulting in ductile failure at most subambient temperatures.
Isotactic Polypropylene Isotactic polypropylene contemplated in embodiments of our invention include those iPPs made using either Ziegler-Natta or metallocene catalysts, or combinations thereof