A summary of the main techniques used to produce plastic products is given below.
Compounding is the basic method used to produce Floreon, where the base PLA, performance and processing additives as well as any colour or pigment are combined together and converted into pellets. This option can be in the form of either as the finished 'Floreon' material or as a concentrated additive masterbatch for addition to unmodified PLA by the converter.
Blown film extrusion is one of the most common methods of processing plastics, in which the molten polymer is fed through an annular die to make a tube which is then inflated to stretch and orientate the polymer chains the material in the circumferential direction. The resulting thin walled film can be collected and either slit to form a flat film, or left as a tube. Typical flat film applications include plastic carrier bags and laminating pouches. Careful specification of the Floreon additives can enhance melt strength and elasticity, widening the processing window for PLA in an application that is traditionally considered challenging for this material.
Film and thin sheets of Floreon can be made by either cast sheet or blown film extrusion. In both processes pellets of the material are fed through an extruder and melted before being passed through a die. In sheet extrusion, a rectangular die is used to form the plastic into a flat sheet which is then passed through rollers in order to flatten it. The material can then be corona treated for printing, or collected directly onto a roll for thermoforming.
During the injection moulding process, plastic pellets or granules are fed from a hopper into a heating chamber. An extrusion screw pushes the plastic through the heating chamber, where the material is softened into a fluid state. Mechanical work and hot sidewalls melt the plastic. At the end of this chamber, the resin is forced at high pressure into a cooled, closed mold. Once the plastic cools to a solid state, the mold opens and the finished part is ejected. This process is used to make a wide range of products including the preforms for bottles, plastic cutlery and other solid plastic moldings.
Floreon was originally developed for injection molding, where the careful specified additives increase the melt flow index of the material. This makes the final compound easier to inject, facilitating injection molding at lower temperatures saving energy and decreasing the load on the machine. The mechanical performance of the resulting products is also better, and cycle times may also be improved.
Injection Stretch Blow molding (ISBM)
Injection stretch blow molding (ISBM) is the technique used to produce carbonated soft drink bottles and other PET containers. In this two-step process an intermediate 'preform' is produced by injection molding. The preform can then be shipped to a bottling facility where it will be softened by heating, before being stretched and blown into a mold to produce the final bottle. The bottle can then be washed and filled for distribution.
Floreon 500 is intended for ISBM, the blend contains around 90% PLA with the rest being the Floreon additive continuing with the extra strength and easier process features.
Floreon has been used for both injection molding and injection stretch blow molding processes. Small bottles can easily be produced using standard PET equipment. Larger (10 litre) bottles have also been produced and plans are being made to scale this up to larger 15 or even 19 litre bottles when sufficient funding is in place.
Extrusion Blow Molding (EBM)
In extrusion blow molding (EBM) molten plastic is passed through an extruder and fed through a die forming a continuous semi-molten tube of thermoplastic material. A chilled mold is clamped around the tube and compressed air is then blown into the tube to solidify the stretched tube. Overall, the goal is to produce a uniform melt, form it into a tube with the desired cross section and blow it into the exact shape of the product.
Floreon 300 has be optimised to suit this process whilst still retaining all the added benefits of strength and end of life options.
As with blown film extrusion, this process requires high melt strength so that the extruded tube or 'parison' can be self-supporting, allowing the mold to successfully grip the parison in order to form the final product. Floreon can be tailored to this process by specifying the right combination and level of additives to produce a low melt flow index, high melt strength compound suitable for EBM.
Thermoforming is a manufacturing process where an extruded plastic sheet is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a usable product. The sheet, or "film" when referring to thinner gauges and certain material types, is heated in an oven to a high-enough temperature that it can be stretched into or onto a mold and cooled to a finished shape. Floreon 600 is suitable for thermoforming and retains its toughness at low temperatures when refrigerated.