Novel slip agents and polypropylene films prepared therefrom

Abstract

Novel polypropylene films are prepared from a composition comprising polypropylene and an N,N—N,N′-bis-alkylene fatty amide having the general structural formula R—CO—NH—(CH 2 ) n —NH—CO—R 1 wherein R and R 1 are the same or different alkyl or alkenyl groups having about 15 to 21 carbon atoms, n is an integer from 2 to 4 and —CO— is a carbonyl group. Such films are found to have improved utility for gravure printing applications.

What is claimed is:  
     
         1 . A composition comprised of polypropylene and an N,N′-bis-alkylene fatty acid amide having the general structural formula R—CO—NH—(CH 2 ) n —NH—CO—R 1  wherein R and R 1  are the same or different alkyl or alkenyl groups having about 15 to 21 carbon atoms —CO— is a carbonyl group and n is an integer from 2 to 4, said N,N′-bis alkylene fatty acid amide being present in an amount from about 0.05 to about 0.5% by weight based on the combined weight of said amide and the polypropylene.  
     
     
         2 . The composition according to  claim 1  wherein the polypropylene is a copolymer of ethylene and propylene containing up to about 6% by weight of ethylene.  
     
     
         3 . The composition according to  claim 2  wherein the N,N′-bis-alkylene fatty acid amide is N,N′-bis-ethylene oleamide.  
     
     
         4 . A polypropylene film comprised of a composition comprising polypropylene and an N,N′-bis-alkylene fatty acid amide, having the general structural formula R—CO—NH(CH 2 ) n —NH—CO—R 1  wherein R and R 1  are the same or different alkyl or alkenyl groups having about 15 to 21 carbon atoms —CO—is a carbonyl group and n is an integer from 2 to 4, said N,N′-bis alkylene fatty acid amide being present in an amount from about 0.05 to 0.25% by weight based on the combined weight of said amide and the polypropylene.  
     
     
         5 . A film according to  claim 4  wherein the polypropylene component is a copolymer of ethylene and propylene containing up to about 6% by weight of ethylene.  
     
     
         6 . A film according to  claim 5  wherein the N,N′-bis-alkylene fatty acid amide is N,N′-bis-ethylene oleamide.  
     
     
         7 . A composite film comprised of a core layer of polypropylene having one or more functional layers on its surfaces, at least one functional layer being a layer comprising polypropylene and an N,N′-bis-alkylene fatty acid amide having the general structural formula R—CO—NH—(CH 2 ) n —NH—CO—R 1  wherein R and R 1  are the same or different alkyl or alkenyl groups having about 15 to 21 carbon atoms —CO— is a carbonyl group and n is an integer from 2 to 4, said N,N′-bis alkylene fatty acid amide being present in an amount from about 0.05 to 0.25% by weight based on the combined weight of said amide and the polypropylene:  
     
     
         8 . A composite film according to  claim 7  wherein the polypropylene component of the said at least one functional layer is a copolymer of ethylene and propylene containing up to about 6% by weight of ethylene.  
     
     
         9 . A composite film according to  claim 8  wherein the N,N′-bis-alkylene fatty acid amide is N,N′-bis-ethylene oleamide.