Synergistic visbreaking composition of peroxide and hydroxylamine ester for increasing the visbreaking efficiency

Abstract

Synergistic visbreaking composition of peroxide and a hydroxylamine ester for increasing the visbreaking efficiency for polypropylene polymers at melt extrusion temperatures below 250° C. and its use in visbreaking polypropylene. The present invention is furthermore related to the use of such visbroken polypropylene polymers for producing melt blown non-wovens with improved barrier properties.

1 . A synergistic visbreaking composition of peroxide and a hydroxylamine ester for increasing the visbreaking efficiency for polypropylene polymers at melt extrusion temperatures below 250° C., comprising peroxide (i) and hydroxylamine ester (ii) in a range of from 1 wt % (i):99 wt % (ii) to 99 wt % (i): 1 wt % (ii)
 wherein the hydroxylamine ester is selected from the group consisting of sterically hindered amine derivatives of the formula: 
 
       
         
           
           
               
               
           
         
         and the peroxide is selected from the group consisting of 2,5-dimethyl-2,5-bis(tert.butyl-peroxy)hexane, 2,5-dimethyl-2,5-bis(tert.butyl-peroxy)hexyne-3, dicumyl-peroxide, di-tert.butyl-peroxide, tert.butyl-cumyl-peroxide and bis (tert.butylperoxy-isopropyl)benzene. 
       
     
     
         2 . (canceled) 
     
     
         3 . The synergistic visbreaking composition according to  claim 1 , comprising pure peroxide (i) and pure hydroxylamine ester (ii) in a range of from 20 wt % (i):80 wt % (ii) to 95 wt % (i):5 wt % (ii). 
     
     
         4 . The synergistic visbreaking composition according to  claim 1 , wherein a to be visbroken polypropylene is a propylene homopolymer or a propylene copolymer with up to 10 wt % of comonomer selected from ethylene, 1-butene, 1-hexene and 1-octene. 
     
     
         5 . A method comprising: increasing the melt flow rate MFR 2  (230° C./2.16 kg) measured according to ISO 1133 of polypropylene polymers at melt extrusion temperatures below 250° C. by adding the synergistic visbreaking composition of peroxide (i) and a hydroxylamine ester(ii) according to  claim 1  to a polypropylene polymer to be visbroken. 
     
     
         6 . A method for increasing the visbreaking efficiency for polypropylene polymers at melt extrusion temperatures below 250° C. comprising: adding the synergistic visbreaking composition of peroxide (i) and a hydroxylamine ester(ii) according to  claim 1  to a polypropylene polymer to be visbroken. 
     
     
         7 . A method comprising: forming melt blown non-wovens with improved barrier properties from polypropylene polymers being visbroken with a synergistic visbreaking composition comprising peroxide (i) and hydroxylamine ester (ii) in a range of from 1 wt % (i):99 wt % (ii) to 99 wt % (i):1 wt % (ii). 
     
     
         8 . A melt blown non-woven comprising polypropylene polymers being visbroken with the synergistic visbreaking composition according to  claim 1 . 
     
     
         9 . An article selected from the group consisting of filtration media (filter), diapers, sanitary napkins, panty liners, incontinence products for adults, protective clothing, surgical drapes, surgical gown, and surgical wear in general, comprising the melt-blown non-wovens according to  claim 8 . 
     
     
         10 . The synergistic visbreaking composition according to  claim 3 , comprising pure peroxide (i) and pure hydroxylamine ester (ii) in a range of 25 wt % (i):75 wt % (ii) to 90 wt % (i):10 wt % (ii). 
     
     
         11 . The synergistic visbreaking composition according to  claim 3 , comprising pure peroxide (i) and pure hydroxylamine ester (ii) in a range of 30 wt % (i):70 wt % (ii) to 85 wt % (i):15 wt % (ii). 
     
     
         12 . The synergistic visbreaking composition according to  claim 3 , comprising pure peroxide (i) and pure hydroxylamine ester (ii) in a range of 50 wt % (i):50 wt % (ii) to 85 wt % (i):15 wt % (ii). 
     
     
         13 . The synergistic visbreaking composition according to  claim 4 , wherein the to be visbroken polypropylene is a propylene homopolymer. 
     
     
         14 . The method according to  claim 6 , comprising adding the peroxide (i) and hydroxylamine ester(ii) as a mixture to the polypropylene polymer to be visbroken. 
     
     
         15 . The method according to  claim 6 , comprising adding the peroxide (i) and hydroxylamine ester(ii) as individual components to the polypropylene polymer to be visbroken.