Process of heat and mass transfers during comoulding of multilayer bottles: effect of parameters

Abstract

The process of moulding for three layer bottles made of a recycled polymer layer injected between two virgin polymer layers is studied in depth. It consists of the following two transfers which take place simultaneously: the heat transfer by conduction through the thickness of the bottle and the mould, as well as at the polymer/bottle interface, and by convection at the internal surface of the bottle where air is located; the diffusion through the thickness of the bottle of the pollutant initially located in the recycled layer. On the other hand, the final material is tested as a bottle in contact with a liquid. Some results of concern are worth noting. Regardless of the temperature of the mould and the surrounding atmosphere (20 or 40°C), the temperature is rapidly decreased through the bottle. As a result, a slight transfer of the potential pollutant is attained at the end of the moulding process. Thus, with the parameters considered for the diffusion of the pollutant, and especially the temperature dependence of the diffusivity of the diffusing substance (pollutant) in the polyethylene terephthalate (PET) bottle, the matter transfer during the moulding stage is so low that it can be considered as negligible.