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Recycling plastics by two‐shot molding
Author(s) -
Donovan R. C.,
Rabe K. S.,
Mammel W. K.,
Lord H. A.
Publication year - 1975
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760151103
Subject(s) - scrap , materials science , molding (decorative) , lamination , composite material , nozzle , shot (pellet) , mechanical engineering , metallurgy , engineering , layer (electronics)
In response to increasing ecological and economic pressures, a two‐shot molding process has been developed to recycle molding plastics. This process buries scrap plastic under a skin of virgin plastic in the molded part, resulting in a laminate that has the appearance of and similar mechanical properties to the skin material only. Two injection units and a special nozzle design are used to achieve the desired lamination. Theoretical and experimental studies have been conducted to determine the effects of parameters on the amount of scrap material that can be buried and its effect on impact strength. With conventional production molding dies, scrap plastic comprising approximately 40 percent of the total shot has been molded beneath virgin plastic in parts having stringent appearance requirements.