Polyethylene-Syndiotactic Polypropylene Composition and Processing Thereof

Abstract

A processable polypropylene composition comprising a mixture of a major amount of a syndiotactic polypropylene and a minor amount of polyethylene wax. The syndiotactic polypropylene has a designated recrystallization temperature, an original minor melting peak and a higher original melting peak. The polyethylene wax provides a recrystallization temperature of the mixture that is greater than the recrystallization temperature of the syndiotactic polypropylene alone and also provides for a minor melting peak and a major melting peak of the mixture, which has a temperature difference which is lower than the difference between the original minor melting peak and the original major melting peak of the syndiotactic polypropylene alone. A process for the production of polypropylene product employing a polyethylene-syndiotactic polypropylene composition as described which is heated to provide a plastic mass of the syndiotactic polypropylene and polyethylene which is processed to provide the product.

1 - 10 . (canceled) 
   
   
       11 . A process for producing a polypropylene product comprising:
 (a) providing an ethylene-polypropylene composition comprising a mixture of:   (i) a predominant amount of a syndiotactic polypropylene having a designated recrystallization temperature and an original minor melting peak and an original second major melting peak; and   (ii) no more than 10 wt. % of a polyethylene wax in admixture with said syndiotactic polypropylene in an amount sufficient to provide a recrystallization temperature of said admixture which is greater than the designated recrystallization peak of said syndiotactic polypropylene and a minor melting peak and major melting peak having a temperature difference which is lower than the temperature difference between said original minor melting peak and said original major melting peak;   (b) heating said polyethylene-polypropylene composition to a temperature in excess of the major melting peak of said composition to provide a plastic mass of said polyethylene-polypropylene composition;   (c) processing said plastic mass to a desired configuration of said product; and   (d) cooling said plastic mass to a temperature below the recrystallization temperature of said admixture to provide said product.   
   
   
       12 . The process of  claim 11  wherein said plastic mass is processed by extruding said plastic mass through a slotted die system to provide a polypropylene film preform which is cooled to a temperature below the crystallization temperature to produce a film. 
   
   
       13 . The process of  claims 11  wherein said plastic mass is introduced into a mold and said plastic mass is cooled to a temperature below the recrystallization temperature to produce a molded product. 
   
   
       14 . The process of  claim 11  wherein said plastic mass is extruded through a fiber die system to produce an elongated fiber which is cooled to a temperature below the recrystallization temperature of plastic mass to form a fiber product. 
   
   
       15 . The process of  claim 11  wherein said polyethylene wax is present in said formulation in an amount to provide an enhancement in the recrystallization temperature of said formulation which is at least 5% greater than the designated recrystallization temperature of said syndiotactic polypropylene without the addition of said polyethylene wax. 
   
   
       16 . The process of  claim 11  where the temperature difference between the major and minor melting peaks of said formulation incorporating said polyethylene wax is less than the temperature difference between the original major and minor peaks without the addition of said polyethylene wax by an increment of at least 2° C. 
   
   
       17 . The process of  claim 11  wherein the slope of the curve defined by the original minor melting peak of said syndiotactic polypropylene and the minor melting peak of said admixture of polyethylene wax and said syndiotactic polypropylene is greater than the slope of the curve defined by the original major melting peak of said syndiotactic polypropylene and the major melting peak of said admixture of polyethylene wax and said syndiotactic polypropylene. 
   
   
       18 . The process of  claim 11  wherein the temperature difference between the recrystallization temperature of said mixture and the minor melting peak of said mixture is less than the difference between said original recrystallization temperature and said original minor melting peak by an increment of at least 1° C.