Process for removing contaminants from polyolefins

Abstract

Polyester and cellulosic contaminants are removed from the surfaces of polyolefins by contacting the polyolefins with an aqueous composition of alkali metal hydroxide and/or alkaline earth metal hydroxide; and with an oxidizing agent.

What is claimed is: 
     
       1. A process for treating polyolefin to remove polyester, and cellulosic contaminants therefrom which comprises contacting polyolefin contaminated with polyester and cellulosic contaminants with an oxidizing agent together with an aqueous composition of a hydroxide selected from the group consisting of alkali metal hydroxide, alkaline earth metal hydroxide and mixtures thereof to thereby cause degradation of polyester and cellulosic contaminants. 
     
     
       2. The process of claim 1 wherein said cellulosic contaminants include cotton. 
     
     
       3. The process of claim 1 wherein said cellulosic contaminants include paper. 
     
     
       4. The process of claim 1 wherein said oxidizing agent is employed as an aqueous composition. 
     
     
       5. The process of claim 1 wherein said oxidizing agent is present in said aqueous composition of a hydroxide. 
     
     
       6. The process of claim 1 wherein said polyolefin is contacted with an aqueous composition containing about 5 to about 50% by weight of said hydroxide and about 0.01% to about 10% by weight of said oxidizing agent. 
     
     
       7. The process of claim 6 wherein said hydroxide consists essentially of sodium hydroxide and said oxidizing agent consists essentially of sodium hypochlorite. 
     
     
       8. The process of claim 6 wherein said aqueous composition contains about 10 to about 30% by weight of said hydroxide and about 0.1 to about 1% by weight of said oxidizing agent. 
     
     
       9. The process of claim 3 wherein said hydroxide consists essentially of sodium hydroxide and said oxidizing agent consists essentially of sodium hypochlorite. 
     
     
       10. The process of claim 6 wherein said aqueous composition contains about 20% by weight of said hydroxide, and about 0.1 to about 1% by weight of said oxidizing agent. 
     
     
       11. The process of claim 10 wherein said hydroxide consists essentially of sodium hydroxide and said oxidizing agent consists essentially of sodium hypochlorite. 
     
     
       12. The process of claim 1 wherein about 1 gallon to about 40 gallons of said aqueous composition per pound of said polyolefin is employed. 
     
     
       13. The process of claim 1 wherein about 1 gallon to about 20 gallons of said aqueous composition per pound of said polyolefin is employed. 
     
     
       14. The process of claim 1 wherein about 2 gallons to about 5 gallons of aqueous composition per pound of said polyolefin is employed. 
     
     
       15. The process of claim 1 which further includes reducing the size of said polyolefin. 
     
     
       16. The process of claim 1 wherein the temperature is about 85° C. to 150° C. 
     
     
       17. The process of claim 1 wherein said polyolefin is selected from the group consisting of polyethylene polypropylene, polyisobutylene, polystyrene polybutene-1 and copolymers of monoolefins with each other. 
     
     
       18. The process of claim 1 which further includes forming fibers from the polyolefin after said contacting. .[.19. Fibers obtained by the process of claim 17..]..[.20. Recycled polyolefin obtained by the process of claim 
     
     
        1..].21. The process of claim 1 which further includes separating the treated polyolefin from said aqueous composition and recycling said 
     
     
        aqueous composition. 22. The process of claim 1 which further includes 
     
     
        forming molded products from the resulting treated polyolefin. 23. The process of claim 1 which further includes forming films from the resulting 
     
     
        treated polyolefin. 24. The process of claim 8 wherein said aqueous compositions contains about 0.12 to about 0.15% by weight of said 
     
     
        oxidizing agent. 25. The process of claim 1 which comprises treating said polyolefin simultaneously with separate compositions of said oxidizing 
     
     
        agent and said hydroxide. 26. The process of claim 1 wherein said 
     
     
        contacting is carried out in the absence of an organic solvent. .Iadd.27. A process for treating polyolefin to remove cellulosic contaminant therefrom which comprises contacting polyolefin contaminated with cellulosic contaminant with an oxidizing agent together with an aqueous composition of a hydroxide selected from the group consisting of alkali metal hydroxide, alkaline earth metal hydroxide and mixtures thereof to thereby cause degradation of cellulosic contaminant. .Iaddend..Iadd.28. The process of claim 27 wherein said cellulosic contaminant includes cotton. .Iaddend..Iadd.29. The process of claim 27 wherein said cellulosic contaminant includes paper. .Iaddend..Iadd.30. The process of claim 27 wherein said oxidizing agent is employed as an aqueous composition. .Iaddend..Iadd.31. The process of claim 27 wherein said oxidizing agent is present in said aqueous composition of a hydroxide. .Iaddend..Iadd.32. The process of claim 27 wherein said polyolefin is contacted with an aqueous composition containing about 5 to about 50% by weight of said hydroxide and about 0.01% to about 10% by weight of said oxidizing agent. .Iaddend..Iadd.33. The process of claim 32 wherein said hydroxide consists essentially of sodium hydroxide and said oxidizing agent consists essentially of sodium hypochlorite. .Iaddend..Iadd.34. The process of claim 32 wherein said aqueous composition contains about 10 to about 30% by weight of said hydroxide and about 0.1 to about 1% by weight of said oxidizing agent. .Iaddend..Iadd.35. The process of claim 34 wherein said hydroxide consists essentially of sodium hydroxide and said oxidizing 
     
     
        agent consists essentially of sodium hypochlorite. .Iaddend..Iadd.36.  The process of claim 32 wherein said aqueous composition contains about 20% by weight of said hydroxide, and about 0.1 to about 1% by weight of said oxidizing agent. .Iaddend..Iadd.37. The process of claim 36 wherein said hydroxide consists essentially of sodium hydroxide and said oxidizing agent consists essentially of sodium hypochlorite. .Iaddend..Iadd.38. The process of claim 27 wherein about 1/2 gallon to about 40 gallons of said aqueous composition per pound of said polyolefin is employed. .Iaddend..Iadd.39. The process of claim 27 wherein about 1 gallon to about 20 gallons of said aqueous composition per pound of said polyolefin is employed. .Iaddend..Iadd.40. The process of claim 27 wherein about 2 gallons to about 5 gallons of aqueous composition per pound of said polyolefin is employed. .Iaddend..Iadd.41. The process of claim 27 wherein the temperature is about 85° C. to 150° C. .Iaddend..Iadd.42. The process of claim 27 wherein said polyolefin is selected from the group consisting of polyethylene, polypropylene, polyisobutylene, polystyrene polybutene-1 and copolymers of monoolefins with each other. .Iaddend..Iadd.43. The process of claim 27 which further includes forming fibers from the polyolefin after said contacting. .Iaddend..Iadd.44. The process of claim 27 which further includes forming 
     
     
        molded products from the resulting treated polyolefin. .Iaddend..Iadd.45. The process of claim 27 which further includes forming films from the resulting treated polyolefin. .Iaddend..Iadd.46. The process of claim 27 wherein said aqueous compositions contains about 0.12 to about 0.15% by weight of said oxidizing agent. .Iaddend..Iadd.47. The process of claim 27 which comprises treating said polyolefin simultaneously with separate compositions of said oxidizing agent and said hydroxide. .Iaddend..Iadd.48. The process of claim 27 wherein said contacting is carried out in the absence of an organic solvent. .Iaddend..Iadd.49. The process of claim 27 wherein said polyolefin is polypropylene. .Iaddend..Iadd.50. The process of claim 27 wherein said polyolefin is polyethylene. .Iaddend.