Manufacturing Process
Plantic's formulations are extruded into Plantic® materials as either resin or sheet using industry standard equipment.
Plantic materials are suitable for a wide range of processing technologies, including extrusion and co-extrusion, injection molding, injection stretch blow molding and extrusion blow molding.
Plantic has a program of formulation development in place to expand the suitability of Plantic® material for the various conversion technologies. This is driven by application and product development in close co-operation with customers' requirements and under consideration of the various conversion processes to be employed.
Plantic® is currently manufactured in a single stage continuous process, from modified corn starch to either a finished roll stock, i.e. sheet, or a resin, which can then be directly converted by a customer.
The raw materials are conveyed to a feeder above the extruder. An extruder processes the materials, heats the starch and feeds the melt, using proprietary screw designs. The extruded melt is then either:
- cast via a standard extrusion sheet die, optimised for Plantic® flow charateristics onto a series of heated rollers, fed through a non-contact gauging system, and then into a dryer system to bring the moisture down to the required level. The sheet is then trimmed, slit as required, and wound onto rolls; or
- extruded through a strand die which is pelletised and dried using conventional processing equipment. Dried resin granules are packed into lined resin bags in a range of industry standard sizes.
Currently, the sheet production process makes sheet up to 950mm wide. The current lines (both sheet and resin) can run at 400kg/hour output each, which is comparable to conventional plastic sheet extrusion lines of the same width. Line efficiencies, including staffing, are comparable to conventional plastic extrusion lines, at 95% or more, as most of the operation is automated.
The capital cost of a Plantic® extrusion line is in line with a PET sheet line of the same output. Lead times for new equipment are also similar, as the only customised designed equipment for the Plantic® line are the dryer and die. Apart from the dryer, there are many suppliers of equipment suitable for the manufacture of Plantic® R1 worldwide.
Plantic manufactures R1 in roll form at its Melbourne facility. Each roll typically weighs 200-300kg. R1 sheet is available in a broad range of colours to suit customer requirements. To aid distribution the company manages a central warehousing, in Belgium, from where it supplies thermoformers in Europe.
There are no theoretical storage restrictions on Plantic® sheet rolls, although a nominal 12 month shelf life has been implemented at this stage. Rolls are stored in dry ambient conditions, wrapped in film to protect the material from changes in relative humidity.
