Injection-stretch blow molding of poly (lactic acid)/polybutylene succinate blends for the manufacturing of bottles

The stretch blow molding process of plastic preforms is widely used for the manufacturing of bottles in numerous market sectors, with high production volumes and low unit costs. In the sector of alcoholic beverages and, in particular, of wine, plastic bottles are used sporadically. Glass bottles or other economic solutions such as laminated cardboard containers or so-called bag-in-boxes are regularly preferred. However, the high ease of use, lightness, recyclability and low cost of plastic materials are the main reasons that are fueling interest especially in wine producers. Poly (ethylene terephthalate) bottles have recently been introduced to the market, although their success has been limited by poor gas impermeability and above all by their recognized high environmental footprint. Barrier can be improved by oxygen scavenger and plasma coating. Environmental footprint is rather low when recycled but that is not well possible with scavenger. Bioplastic materials offer an interesting alternative to fossil-based plastics, combining most of their technical advantages with a lower environmental impact. However, they are more expensive and complex to process. In addition, mechanical and barrier properties are often less than for conventional polymers. In this work, therefore, the development of bioplastic bottles with low gas permeation by stretch blow molding was studied. Poly (lactic acid)-polybutylene succinate blends have been modified by adding additives that obstruct the passage of gaseous molecules through the wall of the bottle. The studies have in particular concerned the extrusion and characterization of bioplastic compounds, the injection molding of preforms, and the blowing of bottles. The results obtained showed that it is possible to obtain low permeation bioplastic bottles, which are an ecological alternative to conventional solutions for packaging.