How multilayer bottles are manufactured?

Answer 1

The answer is not simple. First you'd need to understand how bottles can be manufactured through different processes. Extrusion Blow Molding is a process that allows you to make a bottle using

a) an EXTRUDER to melt and feed material to b) an EXTRUSION HEAD, and then form a c) PARISON (which is a sort of a hot plastic hose that can later be blown with high pressure air) that is brought into a d) MOULD that will cool-down the plastic giving it its final form. In the extrusion head, the hot plastic (fluid) is guided trough some channels that form the Parison, several different systems are used to form a parison, and they vary from manufacturer to manufacturer. Once you have a parison you can superpose it onto another parison (it's like forming an onion) and you can add several parisons to form different layers, you can use different materials as long as you can make them stay united. The multilayer parison is then brought into the mould and blown to adopt the form of it, which can be a bottle or some other forms. In Injection Blow Molding you can also use the multilayer process to form a bottle. The process is quite different here: you need to inject first a preform (which is a sort of tube o proto-bottle) and then you condition its temperature to allow blowing in a next step. For this process you need two molds, one that will be used for injection and the other that will be used to blow the bottle. The preform or proto-bottle is then brought into the blowing mould and blown to the shape of the bottle using high pressure air. To form several layers you need a multi-extruder or canyon capable machine that injects the material layer onto layer. You can have several different materials as long as they are compatible and stick together. I hope this is clear for you - if not, i could expand the answers, and maybe include a picture....