Processing al robot with
Processing al robot with adapted cooling sleeves. The preforms are then left to cool for another four cycles in the downstream cooling block, which is also equipped with adapted cooling sleeves. The removal gripper and the cooling block can be cooled down to a temperature significantly lower than that of the mould. The cooling sleeves employed can be adapted to the shrinkage desired for the respective process. This means that the cooling sleeves of the removal gripper do not need to be identical to those of the cooling block. The removal gripper not only provides for intensive cooling of the preform, but it also calibrates the preform to avoid any deformation. According to Stefan Block, the result is a sufficiently cooled, relatively hard and thus rather insensitive surface of the preform. Improving Part Appearance and Performance Due to the nature of bioplastics, such as PLA, preforms and containers may appear yellowish. By adding of socalled „Anti-Yellow toner“ additives the yellow appearance can be significantly reduced. When coloured containers are desired, creating quality aesthetics in bioplastics parts does not present a problem. PLA can be easily coloured with liquid pigments. Suppliers offer special additives, that bond perfectly with bioplastics. For example Colormatrix Bio range colours are developed with dispersion systems tailored to a bioplastic‘s unique characteristics. The colours will incorporate quickly in the bio-polymer, resulting in good dispersion and inherently consistent colour. Improving PLA Processing To counter the low IR absorption rate of PLA and thus increase the absorption of heat in a blow moulding machine special carbon black additives were developed. A specific reheat additive of Colormatrix, developed for the Bio range of solutions offers a good balance of coulor values and reheat properties. Reheat values can be tailored to meet customer‘s specific reheat requirements with less impact on yellow or lightness characteristics. The strong tendency of PLA to stick to other surfaces can be positively influenced e.g. with Colormatrix‘ Bio range „eze“, a process aid to assist in modification of the polymer surface energy. This additive is designed to work at PLA‘s lower processing temperatures, improving friction and reducing processing costs. Such additives improve release for injection, blow mould and box filling, as well as transport packing of preforms and bottles. Further advantages of using such additives are reduced scratches and blemishes on the container surface. Global Sustainable Solutions Colormatrix Bio range solutions only utilize carrier systems from natural and renewable resources to work in harmony with PLA resulting in environmentally sustainable plastic products. To study the effect of such additives, Colormatrix provided Netstal with all types of additives required. These additives were successfully tested and processed in the trial runs that were carried out jointly with Colormatrix - and the resulting bottles were quite impressive. www.netstal.com; www.colormatrix.com Preforms manufactured on a PETline 3500 with intensive post cooling 18 bioplastics [06/02] Vol. 1
