Blow molding polyethylene resins

Abstract

Disclosed herein are various processes, including continuous fluidized-bed gas-phase polymerization processes for making a high strength, high density polyethylene copolymer, comprising (including): contacting monomers that include ethylene and optionally at least one non-ethylene monomer with fluidized catalyst particles in a gas phase in the presence of hydrogen gas at an ethylene partial pressure of 100 psi or more and a polymerization temperature of 105° C. or less to produce a polyethylene copolymer having a density of 0.945 g/cc or more and an ESCR Index of 1.0 or more wherein the catalyst particles are prepared at an activation temperature of 700° C. or less, and include silica, chromium, and titanium.

1 . A continuous fluidized-bed gas-phase polymerization process for making a high strength, high density polyethylene copolymer, comprising: contacting monomers that include ethylene and optionally at least one non-ethylene monomer with fluidized catalyst particles in a gas phase in the presence of hydrogen gas at an ethylene partial pressure of 100 psi or more, to produce a polyethylene copolymer having a density of 0.945 g/cc or more and an ESCR Index of 1.0 or more wherein the catalyst particles are prepared at an activation temperature of 700° C. or less, and said catalyst consists essentially of silica, chromium, and titanium.  
   
   
       2 . A continuous fluidized-bed gas-phase polymerization process for making a high strength, high density polyethylene copolymer, comprising: contacting monomers that include ethylene and optionally at least one non-ethylene monomer with fluidized catalyst particles in a gas phase in the presence of hydrogen gas at an ethylene partial pressure of 100 psi or more, to produce a polyethylene copolymer having a density of 0.945 g/cc or more, an ESCR Index of 1.0 or more, and a Die Swell of from 80% to 100%, wherein the catalyst particles are prepared at an activation temperature of 650° C. or less, and said catalyst consists essentially of silica, chromium, and titanium.  
   
   
       3 . A continuous gas-phase polymerization process for making a high strength, high density polyethylene copolymer, comprising: contacting monomers that include ethylene and optionally at least one non-ethylene olefin with fluidized catalyst particles in a gas-phase fluidized-bed reactor in the presence of hydrogen gas at an ethylene partial pressure of 100 psi or more, to produce a polyethylene copolymer having a density of from 0.945 to 0.960 g/cc and an ESCR Index of 1.0 or more, wherein: 
 (a) the catalyst particles include a silica support that is porous and has a surface area of less than 400 square meters per gram;    (b) the catalyst particles have been prepared by contacting the silica support with a combination consisting of a chromium compound and a titanium compound in a vessel; raising the internal temperature of the vessel containing the dried particles and dry air to a final activation temperature of 650° C. or below; to form activated catalyst particles; lowering the internal temperature of the vessel containing the activated catalyst particles; removing air from the vessel using dry nitrogen; and    (c) the polyethylene resin is formed with a bulk density of 20 lb/ft3 or more;    (d) the polyethylene resin has an ESCR Index of 1.0 or more;    (e) the polyethylene resin has a density of from 0.945 to 0.960 g/cc;    (f) the polyethylene resin has a Molecular Weight Distribution of from 15 to 30.    
   
   
       4 . The process of  claim 1  wherein the ESCR Index is 1.2 or greater.  
   
   
       5 . The process of  claim 3  wherein the ESCR Index is 1.2 or greater.  
   
   
       6 . The process of  claim 1  wherein the density of the polyethylene copolymer is from 0.950 to 0.965 and the ESCR Index is 1.2 or greater.  
   
   
       7 . The process of  claim 1  wherein the ESCR Index is 1.3 or greater.  
   
   
       8 . The process of  claim 3  wherein raising the internal temperature of the vessel containing the dried particles to a final activation temperature of 650° C. or below includes raising the internal temperature of the vessel containing the dried particles and dry air at a rate of from 25 to 55° C. per hour to the final activation temperature and the polyethylene resin is formed at a polymerization temperature of 100° C. or less.  
   
   
       9 . The process of  claim 3  wherein rising the internal temperature of the vessel containing the dried particles to a final activation temperature of 650° C. or below includes raising the internal temperature of the vessel containing the dried particles and dry air at a rate of from 25 to 55° C. per hour to the final activation temperature and the polyethylene resin is formed at a polymerization temperature of 100° C. or less.  
   
   
       10 . The process of  claim 1  wherein the polyethylene resin has a Percent Die Swell of 80% or more.  
   
   
       11 . The process of  claim 3  wherein the polyethylene resin has a Percent Die Swell of 80% or more.  
   
   
       12 . The process of  claim 1  wherein the supported catalyst particles are prepared using an activation temperature of 650° C. or less, than 600° C. or less, or 550° C. or less.  
   
   
       13 . The process of  claim 1  wherein the ESCR Index is 1.4 or more  
   
   
       14 . The process of  claim 1  wherein the chromium is present in the amount of less than 1.0 wt %.  
   
   
       15 . The process of  claim 1  wherein the non ethylene monomer is 1-butene, 1-hexene, or 1-octene, or mixtures thereof.  
   
   
       16 . The process of  claim 1  wherein the ethylene partial pressure is 100 psi or greater.  
   
   
       17 . The process of  claim 1  wherein the catalyst productivity is 4000 lb/lb or more.  
   
   
       18 . The process of  claim 1  wherein the catalyst productivity is 4000 lb/lb or more with a residence time of 2 hours or more.  
   
   
       19 . The process of  claim 1  wherein the H2/C2 molar ratio in the cycle gas is 0.01 or more.  
   
   
       20 . The process of  claim 1  wherein the monomers arm directed through a reactor that includes at least a first section having a first diameter and a second section having a second diameter, wherein the second diameter is larger than the first diameter.  
   
   
       21 . The process of  claim 1  wherein oxygen is present in the range of about 10 to 500 ppbv based on the ethylene feed rate.  
   
   
       22 . The process of  claim 1  wherein the surface area of the catalyst support is less than 400 square meters per gram.  
   
   
       23 . The process of  claim 1  wherein the polyethylene resin is formed with a bulk density of 20 lb/ft 3  or more.  
   
   
       24 . The process of claims  1 ,  2  or  3  wherein the polymerization is conducted in the presence of triethyl aluminum.  
   
   
       25 . A continuous fluidized-bed gas-phase polymerization process for making a high strength, high density polyethylene copolymer, comprising: contacting monomers that include ethylene and optionally at least one non-ethylene monomer with fluidized catalyst particles in a gas phase in the presence of hydrogen gas at an ethylene partial pressure of 100 psi or more to produce a polyethylene copolymer having a density of 0.945 g/cc or more and an ESCR Index of 1.5 or more wherein the catalyst particles are prepared at an activation temperature of 700° C. or less, and said catalyst consists essentially of silica, chromium, and titanium.  
   
   
       26 . The continuous fluidized-bed gas phase polymerization process of  claim 25 , wherein said activation temperature is one of less than 650° C., or less than 600° C. or less than 550° C.