Very low density polyethylene blends

Abstract

Blends of very low density polyethylene produced using metallocene catalysts (mVLDPE) and linear low density polyethylene (LLDPE) are disclosed. The polymer blends include a metallocene-catalyzed VLDPE polymer having a density of less than 0.916 g/cm 3 , the VLDPE polymer preferably being linear and without long chain branching, and a LLDPE polymer having a density of from 0.916 to 0.940 g/cm 3 . The polymer blends are particularly suitable in blown and cast film applications.

1 - 2 . (canceled)  
   
   
       3 . A multilayer film, comprising a first layer and a second layer, at least one of the layers comprising a polymer blend composition, the polymer blend composition comprising: 
 (i) a copolymer derived from ethylene and one or more C 3 -C 20  alpha olefin comonomers, said copolymer having: 
 a) a comonomer content of from 5 to 15 wt. %,  
 b) a density of less than 0.916 g/cm 3 ,  
 c) a composition distribution breadth index in the range of from 55% to 70%,  
 d) a molecular weight distribution Mw/Mn of from 2 to 3,  
 e) a molecular weight distribution Mz/Mw of less than 2, and  
 f) a bi-modal composition distribution; and  
   (ii) a linear low density polyethylene polymer having a density of from 0.916 to 0.940 g/cm 3 .    
   
   
       4 . (canceled)  
   
   
       5 . An article, comprising a substrate and a film disposed on the substrate, the film comprising a polymer blend composition, the polymer blend composition comprising: 
 (i) a copolymer derived from ethylene and one or more C 3 -C 20  alpha olefin comonomers, said copolymer having: 
 a) a comonomer content of from 5 to 15 wt. %,  
 b) a density of less than 0.916 g/cm 3 ,  
 c) a composition distribution breadth index in the range of from 55% to 70%,  
 d) a molecular weight distribution Mw/Mn of from 2 to 3, and  
 e) a molecular weight distribution Mz/Mw of less than 2; and  
   (ii) a linear low density polyethylene polymer having a density of from 0.916 to 0.940 g/cm 3 .    
   
   
       6 . The multi-layer film, or the article of  claim 5 , wherein the copolymer is produced using an unbridged bis-Cp metallocene catalyst system.  
   
   
       7 . The multi-layer film, or the article of claim or  5 , wherein the copolymer is produced in a gas phase polymerization process.  
   
   
       8 . The multi-layer film, or the article of claim or  5 , wherein the copolymer is produced in a gas phase polymerization process at a pressure in the range of from 100 psig to 1000 psig.  
   
   
       9 . The multi-layer film, or the article of claim or  5 , wherein the copolymer is produced using an unbridged bis-Cp metallocene catalyst system in a gas phase polymerization process at a pressure in the range of from 100 psig to 1000 psig.  
   
   
       10 . The multi-layer film of  claim 3 , wherein the copolymer has a melt index of 5 g/10 minutes or less.  
   
   
       11 . The article of  claim 4   5 , wherein the copolymer has a melt index of 5 g/10 minutes or more.  
   
   
       12 - 13 . (canceled)  
   
   
       14 . A multilayer film, comprising a first layer and a second layer, at least one of the layers comprising a polymer blend composition, the polymer blend composition comprising: 
 (a) a metallocene-catalyzed linear very low density polyethylene polymer having: 
 (i) a density of less than 0.916 g/cm 3 ,  
 (ii) a composition distribution breadth index of 50 to 85% by weight,  
 (iii) a molecular weight distribution Mw/Mn of 2 to 3,  
 (iv) a molecular weight distribution Mz/Mw of less than 2, and  
 (v) two peaks in a TREF measurement,  
   (b) a linear low density polyethylene polymer having a density of from 0.916 to 0.940 g/cm 3 .    
   
   
       15 . (canceled)  
   
   
       16 . An article, comprising a substrate and a film disposed on the substrate, the film comprising a polymer blend composition, the polymer blend composition comprising: 
 (a) a metallocene-catalyzed linear very low density polyethylene polymer having: 
 (i) a density of less than 0.916 g/cm 3 , 
 (ii) a composition distribution breadth index of 50 to 85% by weight,  
 
 (iii) a molecular weight distribution Mw/Mn of 2 to 3, and 
 (iv) a molecular weight distribution Mz/Mw of less than 2, and  
 
 (b) a linear low density polyethylene polymer having a density of from 0.916 to 0.940 g/cm 3 .  
   
   
   
       17 . The multi-layer film, or the article of  claim 14  or  16 , wherein the very low density polyethylene polymer is a gas-phase metallocene produced very low density polyethylene polymer.  
   
   
       18 . The multi-layer film, or the article of  claim 14  or  16 , wherein the very low density polyethylene polymer has a density of from 0.900 to 0.915 g/cm 3 .  
   
   
       19 . The multi-layer film, or the article of  claim 14  or  16 , wherein the very low density polyethylene polymer is a comonomer of ethylene and at least one comonomer selected from the group consisting of C 3  to C 12  alpha olefins.  
   
   
       20 . The multi-layer film, or the article of  claim 14  or  16 , wherein the linear low density polyethylene polymer is a metallocene-catalyzed linear low density polyethylene polymer.  
   
   
       21 . The multi-layer film, or the article of  claim 14  or  16 , wherein the linear low density polyethylene polymer is a gas-phase metallocene produced linear low density polyethylene polymer.  
   
   
       22 . The multi-layer film, or the article of  claim 14  or  16 , wherein the linear low density polyethylene polymer is a Ziegler-Natta produced linear low density polyethylene polymer.  
   
   
       23 . The multi-layer film, or the article of  claim 14  or  16 , wherein the linear low density polyethylene polymer has a melt index of from 0.5 to 20 g/10 min.  
   
   
       24 . The multi-layer film, or the article of  claim 14  or  16 , wherein the linear low density polyethylene polymer is a comonomer of ethylene and at least one comonomer selected from the group consisting of C 3  to C 12  linear alpha olefins.  
   
   
       25 . The multi-layer film, or the article of  claim 14  or  16 , wherein the blend comprises 5-80% by weight of the very low density polyethylene polymer and 95-20% by weight of the linear low density polyethylene polymer, based on the total weight of the very low density polyethylene and linear low density polyethylene polymers.  
   
   
       26 . The multi-layer film, or the article of  claim 14  or  16 , wherein the blend further comprises a second very low density polyethylene polymer having a density of less than 0.916 g/cm 3 .  
   
   
       27 . The multi-layer film; or the article of  claim 14  or  16 , wherein the blend further comprises a second linear low density polyethylene polymer having a density of from 0.916 to 0.940 g/cm 3 .  
   
   
       28 . The multi-layer film of  claim 14 , wherein the very low density polyethylene polymer has a melt index of 5 g/10 min or less.  
   
   
       29 . The multilayer film of  claim 14 , wherein the multilayer film comprises at least layers including a top layer, a bottom layer, and a middle layer.  
   
   
       30 . The multilayer film of  claim 29 , wherein one of the top layer and the bottom layer comprises the polymer blend composition.  
   
   
       31 . The multilayer film of  claim 29 , wherein the top layer and the bottom layer comprise the polymer blend composition.  
   
   
       32 . The multilayer film of  claim 29 , wherein the middle layer comprises the polymer blend composition.  
   
   
       33 . The multilayer film of  claim 14 , wherein the film has a dart drop value of at least 5 g/μm.  
   
   
       34 . The multilayer film of  claim 14 , wherein at least one layer does not include the polymer blend and comprises a very low density polyethylene, a low density polyethylene, a linear low density polyethylene, a medium density polyethylene, a high density polyethylene, an ethylene-acrylic acid copolymer, an ethylene-vinyl acetate copolymer, an ethylene-methacrylic acid copolymer, an ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyethylene terephthalate, oriented polypropylene, nylon, or a mixture thereof.  
   
   
       35 . The article of  claim 16 , wherein the very low density polyethylene polymer has a melt index of 5 g/10 min or more.  
   
   
       36 . The article of  claim 16 , wherein the film comprises a monolayer film.  
   
   
       37 . The article of  claim 16 , wherein the film comprises a multilayer film.  
   
   
       38 . The article of  claim 16 , wherein the film is extrusion coated on the substrate.  
   
   
       39 . The article of  claim 16 , wherein the film is laminated to the substrate.  
   
   
       40 . The article of  claim 16 , wherein the substrate is selected from the group consisting of glass, plastic, metal foil, and paper.