Coextrusion blow molding technology

The multilayer coextrusion blow molding technology can be used for a wide variety of containers made from LCP and other thermoplastics. Figure 11.36 shows a multilayer bottle and tray made from LCP and PET by coextrusion blow molding. Figure 11.37 shows high barrier bottles made with LCP and PET. 

Technology to successfully produce multilayer injection blow molded bottles is much newer than that to produce multilayer extrusion blow molded bottles. Heinz Inc. s ketchup bottle was the first U.S. example (Fig. 12.22). The use of PET bottles made by coinjection blow molding has grown rapidly. As is the case for coextrusion blow molding, the key is production of the parison. Once the multilayer parison is produced, the remainder of the process is essentially the same as for single layer materials. Even stretch blow molding can be used. 

Thielen, M., Blow Molding, Sequential Coextrusion Advanced Technology Opens Door into a New World of Tailored Parts, Modem Plastics Encyclopaedia, 1999. 

Blow molded parts demonstrate that, from technical and cost standpoints, BM offers a promising alternative to other processes, particularly injection molding (IM) and thermoforming. The technical evolution of BM, plus accompanying improvements and new developments in plastics, has led to new BM parts. With the coextrusion technology now established and the hardware in place, the variety of achievable properties can readily be extended by the correct combination of different materials (see Chapter 3). The potential for BM products includes much more than the simple bottles that have been made for many decades. Now the expertise and economics of the method are such that many ideas once deemed futuristic are much closer to realization (2, 96, 186-212). 

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