Polyolefins and process for manufacturing them

Abstract

Process for producing polyolefins, comprising the following steps: a) grafting of acid groups onto polyolefins by means of a graftable monomer bearing at least one functional group chosen from a carbonyl and an acid anhydride, optionally in the presence of another graftable monomer bearing a vinyl unsaturated group and, optionally, one or more aromatic rings; b) purification, consisting in removing at least some of the graftable monomer bearing at least one functional group chosen from a carbonyl and an acid anhydride that has not reacted with the polyolefins; c) neutralization of the acid groups by at least one neutralizing agent. Polyolefin obtained.

1 - 26 . (canceled)  
     
     
         27 . A process for producing a polyolefin, comprising: 
 a) grafting in an extruder and in the presence of a radical generator acid groups onto a polyolefin by means of a graftable monomer bearing at least one functional group chosen from the group consisting of a carbonyl and an acid anhydride, optionally in the presence of another graftable monomer bearing a vinyl unsaturated group and, optionally one or more aromatic rings;    b) purifying the product of step a) by removing at least a portion of the graftable monomer bearing at least one functional group chosen from the group consisting of a carbonyl and an acid anhydride that has not grafted with the polyolefin to produce a purified product;    c) neutralizing in an extruder the acid groups of the purified product by reacting with at least one neutralizing agent, wherein    the neutralizing agent comprises a cationic part comprising one or more cations chosen from the group consisting of Al+3, alkaline-earth cations and transition-metal cations and/or    the neutralization agent comprises an anionic part comprising one or more anions selected from the group consisting of alcoholates, carboxylates and alkyls.    
     
     
         28 . The process according to  claim 27 , wherein the neutralizing agent comprises a cationic part comprising one or more cations selected from the group consisting of Al +3 , alkaline-earth cations and transition-metal cations.  
     
     
         29 . The process according to  claim 28 , wherein the neutralizing agent comprises a cationic part comprising Al +3 , Mg +2 , Zr +4  and Zn +2 .  
     
     
         30 . The process according to  claim 27 , wherein the neutralizing agent comprises an anionic part comprising one or more anions selected from the group consisting of alcoholates, carboxylates and alkyls.  
     
     
         31 . The process according to  claim 30 , wherein the neutralizing agent comprises an anionic part comprising one or more anions selected from the group consisting of alcoholates.  
     
     
         32 . The process according to  claim 30 , wherein the neutralizing agent comprises an anionic part comprising one or more anions selected from the group consisting of carboxylates.  
     
     
         33 . The process according to  claim 30 , wherein the neutralizing agent comprises a cationic part comprising one or more cations selected from the group consisting of Al +3 , alkaline-earth cations and transition-metal cations.  
     
     
         34 . The process according to  claim 33 , wherein the neutralizing agent comprises a cationic part comprising Al +3 , Mg +2 , Zr +4  and Zn +2 .  
     
     
         35 . The process according to  claim 33 , wherein the neutralizing agent is zinc acetate.  
     
     
         36 . The process according to  claim 27 , wherein the neutralizing agent is added in an amount of from 0.1 to 1000 meq./kg of polyolefin grafted with acid groups.  
     
     
         37 . The process according to  claim 27 , wherein the polyolefin is selected from homopolymers of ethylene and homopolymers of propylene.  
     
     
         38 . The process according to  claim 27 , wherein the polyolefin is selected from copolymers of ethylene with one or more comonomer(s) selected from linear olefin comprising from 2 to 8 carbon atoms and copolymers of propylene with one or more comonomer(s) selected from linear olefin comprising from 2 to 8 carbon atoms.  
     
     
         39 . The process according to  claim 27 , wherein the graftable monomer bearing at least one functional group is selected from the group consisting of a carbonyl and an acid anhydride is maleic anhydride.  
     
     
         40 . The process according to  claim 27 , wherein the graftable monomer bearing at least one functional group selected from the group consisting of a carbonyl and an acid anhydride is added in an amount of from 0.01 to 10% by weight with respect to the polyolefin.  
     
     
         41 . The process according to  claim 27 , wherein the process is carried out in the absence of a graftable monomer bearing a vinyl unsaturated group and, optionally one or more aromatic rings.  
     
     
         42 . The process according to  claim 27 , wherein purifying is carried out by removal of at least a portion of the graftable monomer with acetone, by hot-air stripping, by steam stripping, by stripping with an inert gas or by venting.  
     
     
         43 . The process according to  claim 27 , further comprising the step of purifying d), said purifying d) comprising removing a product arising from neutralizing the grafted acid groups, wherein purifying d) follows neutralizing c).  
     
     
         44 . The process according to  claim 27 , wherein the extruder is made of a corrosion-resistant alloy.  
     
     
         45 . The process according to  claim 27 , wherein the process is carried out in a continuous process comprising a single step for melting the polyolefin.  
     
     
         46 . The process according to  claim 27 , further comprising adding during the process 1,3,5-trimethyl-2,4,6-tris-(3,5-tert-butyl-4-hydroxybenzyl)benzene.  
     
     
         47 . A polyolefin produced by the process of  claim 27 , comprising a plurality of partially neutralized acid groups, said polyolefin having a melt flow index, measured at 230° C. under a load of 2.16 kg for propylene polymers according to ASTM D 1238 Standard and at 190° C. under a load of 5 kg for ethylene polymers according to ISO 1133 Standard, of from 0.001 to 1000 dg/min and an improved melt strength characterized by an exponential increase in the elongational viscosity as a function of time and by an increase in the dynamic viscosity at low shear frequencies.  
     
     
         48 . The polyolefin according to  claim 47 , comprising ionic aggregates having a shape similar to a bunch of grapes, the size of said bunch being between 10 and 500 nm and the size of a grape being less than 50 nm.  
     
     
         49 . A process comprising extrusion foaming, thermoforming or blow molding the polyolefin claimed in  claim 47 .  
     
     
         50 . A process comprising compatibilizing, sealing or adhering wherein the polyolefin claimed in  claim 47  is the compatibilizer, sealant or adhesive.  
     
     
         51 . An extrusion foaming process comprising extrusion foaming a material, wherein said extrusion foaming process is carried out consecutively to the polyolefin production process