13-06-2019 дата публикации
Номер: US20190177448A1
Принадлежит:
The invention is related to a process for producing modified polyethylene having decreased melt flow rate (5 kg, 190° C.) (MFR). In particular, the present invention is directed to a process in a controlled manner for producing modified polyethylene recyclates having low MFR and low gel content directly by reactive extrusion processing. 1. A process for obtaining a controlled reduction of the melt flow rate (5 kg , 190° C.) (MFR) of a polyethylene by modifying the polyethylene , the polyethylene having a starting melt flow rate (5 kg , 190° C.) (MFR) and a melting temperature , the process comprising the steps of:{'sub': '0', '(a) determining the starting melt flow rate (5 kg, 190° C.) (MFR) of the polyethylene,'}(b) feeding the polyethylene into an extrusion device,(c) feeding a peroxide into the extrusion device, wherein the peroxide is provided in an amount of X ppm over the weight of the polyethylene, wherein the amount of peroxide X is in a range of 300 ppm to 4000 ppm,(d) mixing the polyethylene with the peroxide in the extrusion device at a temperature above the melting point of the polyethylene to form a mixture that is substantially homogeneous,{'sub': 'f', '(e) extruding the mixture obtained from step (d) to provide a modified polyethylene having a final melt flow rate (5 kg, 190° C.) (MFR),'}{'sub': 'f', '(f) determining the final melt flow rate (5 kg, 190° C.) (MFR) of the modified polyethylene obtained from step (e),'}{'sub': f', '0, 'claim-text': {'br': None, 'sub': 'f', 'i': '×e', 'sup': '−μX', 'MFR=MFR0\u2003\u2003(I)'}, 'characterized in that the final melt flow rate (5 kg, 190° C.) (MFR) of the modified polyethylene fulfills an exponential decay defined by equation (I) with respect to the starting melt flow rate (5 kg, 190° C.) (MFR) and the concentration (X) of the peroxide based on the amount of polyethylene,'}wherein μ is an exponential decay constant and is from 0.0005 to 0.005.2. The process according to claim 1 , characterized in that the ...
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