In Europe, Kautex is regarded as the inventor of blow molding technology. The first machine for the production of plastic bottles was developed back in 1949.
In blow molding technology, continuous extrusion is the basic process for the production of blow molded articles from a parison. In this manufacturing process that is still used today, the extrusion speed depends on the screw r.p.m.
Characteristics for continuous extrusion:
Materials with high viscosity
High melt stiffness
Short, light parisons
Coextrusion, especially with thin layers
As early as the 1960s, blow molded articles were starting to exceed the critical limit of between 80 and 100 liters and were therefore too large for the continuous extrusion process that had been used up to then.
So Kautex developed this process in order to maximize the output rate for the production of larger products.
In contrast to continuous extrusion, in this process the melt is transported into a storage chamber and, after the previous part has been released from the mold, it is ejected all at once at high speed. This means that the extrusion speed is much higher and is no longer dependent on the screw r.p.m. The storage chamber can be refilled again during the cooling and mold release stages.
Discontinuous extrusion necessitates the use of accumulator heads.
Characteristics for discontinuous extrusion:
Materials with low viscosity
Low melt stiffness
Long, heavy parisons
e.g. barrels, IBC (Intermediate Bulk Containers), fuel tanks (Mono, Selar)
High rate of output
Low draw-down of the parison
Less cooling of the parison lower end
The coextrusion process has been offered by Kautex Maschinenbau since the early 1980s. It was developed to meet new requirements in agricultural chemicals packaging.
The term "coextrusion" stands for the simultaneous processing of diverse materials that are bonded in the extrusion head into a multi-layer parison by means of an adhesive promoter. For particularly challenging applications, Kautex Maschinenbau offers equipment for the production of up to seven layers.
Low requirements for master batches in the outer decorative layer reduce the costs of Deco/Reco produced parts and additionally allows regrind or recycled material to be embedded into the middle layer. This process, with the inclusion of a suitable barrier layer, can be used toprotect food products from environmental influences and prevent chemicals from being discharged into the environment.