Metallocene produced polyethylene for fibres applications

Abstract

The present invention provides monofilaments or stretched tapes, unwoven or woven into raffia, prepared with metallocene-produced polyethylene having long chain branches.

1 - 8 . (canceled)  
     
     
         9 . Monofilaments or stretched tapes, unwoven or woven into raffia prepared from a metallocene-produced polyethylene resin having long chain branches.  
     
     
         10 . The monofilaments or stretched tapes of  claim 9  wherein the metallocene component is a tetrahydroindenyl.  
     
     
         11 . The monofilaments or stretched tapes of  claim 9  produced by the steps comprising: 
 (a) providing a metallocene-produced medium density polyethylene resin having long chain branches;    (b) producing a film from the polyethylene resin of step (a);    (c) orienting the film obtained from step (b) by stretching;    (d) cutting the film of step (b) into strips; and    (e) optionally, annealing the stretched film.    
     
     
         12 . The monofilaments or stretched tapes of  claim 11  wherein the stretching is carried out at a temperature from about 10 to about 70° C. lower than the melting temperature of the resin.  
     
     
         13 . The monofilaments or stretched tapes of  claim 12  wherein the stretched film is annealed at a temperature of from about 5 to about 10° C. lower than the stretching temperature.  
     
     
         14 . The monofilaments or stretched tapes of  claim 11  wherein the stretching is performed by passing the film over a first and second roller and the ratio of the roller's velocities is in the range of from about 5 to about 7.  
     
     
         15 . The monofilaments or stretched tapes of  claim 14  wherein the stretching is carried out at a temperature from about 10 to about 70° C. lower than the melting temperature of the resin and the stretched film is annealed at a temperature of from about 5 to about 10° C. lower than the stretching temperature.  
     
     
         16 . A process for preparing stretched tapes that comprises the steps of: 
 (a) providing a metallocene-produced medium density polyethylene resin having long chain branches;    (b) producing a film from the polyethylene resin of step (a);    (c) orienting the film obtained from step (b) by stretching;    (d) cutting the film of step (b) into strips; and    (e) optionally, annealing the stretched tapes.    
     
     
         17 . The process of  claim 16  wherein step (d) is performed before step (c).  
     
     
         18 . The process of  claim 16  wherein step (c) is performed before step (d).  
     
     
         19 . The process of  claim 16  wherein the stretching is carried out at a temperature from about 10 to about 70° C. lower than the melting temperature of the resin.  
     
     
         20 . The process of  claim 19  wherein the stretching is carried out at a temperature from about 15 to about 50° C. lower than the melting temperature of the resin.  
     
     
         21 . The process of  claim 16  wherein the stretching is performed by passing the film over a first and second roller and wherein the ratio of the roller's velocities is in the range of from about 5 to about 7.  
     
     
         22 . The process of  claim 21  wherein the stretching is carried out at a temperature from about 10 to about 70° C. lower than the melting temperature of the resin.  
     
     
         23 . The process of  claim 22  wherein the stretched film is annealed at a temperature of from about 5 to about 10° C. lower than the stretching temperature.  
     
     
         24 . The process of  claim 23  wherein the annealing is carried out while transferring the film from the second stretcher roller to a third roller and wherein the velocity of the third roller is less than that of the second roller.  
     
     
         25 . The process of  claim 23  wherein the stretching is carried out at a temperature from about 15 to about 50° C. lower than the melting temperature of the resin.  
     
     
         26 . The process of  claim 19  wherein the film is annealed at a temperature of from about 5 to about 10° C. lower than the stretching temperature.  
     
     
         27 . The process of  claim 16  wherein the metallocene-produced resin is produced using a tetrahydroindenyl component.