Thermoplastic polymer compositions, methods for making the same, and articles made therefrom

摘要

Provided are thermoplastic polymer compositions having a single melting point, articles made therefrom, and methods for elevating the melting point of low melting point polymers. Thermoplastic polymer compositions are composed of one or more high melting point polyolefins and a thermoplastic component that includes a low melting point polypropylene. High melting point polyolefins are composed of a stereoregular polypropylene having a tacticity similar to the low melting point polypropylene. The low melting point polypropylene includes, for example, propylene homopolymers and copolymers composed of propylene and one or more comonomers. Thermoplastic polymer compositions may also optionally contain any of the various additives commonly used in such polymer compositions, such as for example oils, etc. In one embodiment, thermoplastic polymer compositions are thermoplastic elastomer compositions that include an elastomeric component composed of an elastomer or rubber. The elastomeric component may be substantially or partially crosslinked to form a thermoplastic vulcanizate.

主权项

1. A thermoplastic polymer composition comprising:
at least 40 weight percent, based on the weight of the thermoplastic polymer composition, of a thermoplastic component comprising low melting point copolymer having a melting temperature of greater than or equal to 107.5° C. and not more than about 150° C. composed of stereoregular polypropylene segments and from about 0.1 to about 5.0 weight percent of ethylene-derived units, based on the weight of the low melting point copolymer, and at least 20 weight percent, based on the weight of the thermoplastic polymer composition, of a high melting point polyolefin having a melting point of greater than 150° C. and greater than the melting point of the low melting point copolymer, wherein the thermoplastic polymer composition has a single melting point of at least 161.9° C.; and wherein the melting point of the thermoplastic polymer composition is within at least about 15% of the melting point of the high melting point polyolefin according to the follow formula:100*[Tm⁡[C]⁢high⁢⁢⁢melting⁢⁢point⁢⁢⁢polyolefin-Tm⁡[C]⁢thermoplastic⁢⁢polymer⁢⁢composition]Tm⁡[C]⁢high⁢⁢⁢melting⁢⁢point⁢⁢polyolefin≤15⁢%.