Orientation of Films to Improve Barrier and UV Stability

Abstract

The invention disclosed herein relates to a method of treating plastics material fibres, filaments or film to improve their resistance to degradation by UV radiation and/or increase their resistance to gas (oxygen) transmissivity and an improved plastics material so treated, the method including stretching the fibre, filament or film beyond its yield point and allowing the film to at least partially relax.

1 - 8 . (canceled) 
     
     
         9 . A plastics material member having a decreased oxygen permeability uniformly across a transverse cross-section of said plastics material member, said plastics material member being a film, fibre or filament, stretched beyond its yield point to decrease its thickness and increase its length, the transverse cross-section being transverse to the stretching direction, and said plastics material member being partially relaxed substantially uniformly across the transverse cross-section by between 5 and 20% of the plastics materials member's total stretched length. 
     
     
         10 . (canceled) 
     
     
         11 . A plastics material member having an increased resistance to UV degradation uniformly across a transverse cross-section of said plastics material member, said plastics material member being a film, fibre or filament, stretched beyond its yield point to decrease its thickness and increase its length, the transverse cross-section being transverse to the stretching direction, and said plastics material member being partially relaxed substantially uniformly across the transverse cross-section by between 5 and 20% of the plastic material member's total stretched length. 
     
     
         12 . A plastics material member according to  claim 9 , wherein the stretched plastics material member is relaxed by at least 10% of its total stretched length. 
     
     
         13 - 25 . (canceled) 
     
     
         26 . A plastics material film for forming an anaerobic wrapping envelope that has first been stretched beyond its yield point to increase its length and reduce its thickness, said film being partially relaxed substantially uniformly across its cross-section transverse to the stretching direction by between 5 and 20% of its total stretched length. 
     
     
         27 . An anaerobic wrapping envelope including at least one layer of overlapping plastics material film stretched beyond its yield point to increase its length and reduce its thickness, said film being at least partially relaxed substantially uniformly across its cross-section transverse to the stretching direction by between 5 and 20% of its total stretched length before being configured to form said anaerobic wrapping envelope. 
     
     
         28 . (canceled) 
     
     
         29 . A plastics material member according to  claim 11 , wherein the stretched plastics material member is relaxed by at least 10% of its total stretched length.