Toys Bio-alternatives
Toys Bio-alternatives for soft PVC Bio-alternatives for plasticized vinyl chloride polymers Table 1: Composition of PVC Bio-alternatives developed by SKZ Component Content (wt.%) Biopolymers (matrix) 57,0 Other polymers (elastic component) 5,0 Bio based plasticizer (softening agent) 19,5 Fillers (inorganic ingredients) 16,0 Additives (coupling agents, lubricants, etc.) 2,5 Figure 1: Build-up of the compounding line used: 1 - Compounder; 2 - Solid dosage; 3 - Liquid dosage; 4 - Atmospheric degassing; 5 - Water bath; 6 - Conveyer belt; 7 - Pelletizer Figure 2: Hardness and Young’s modulus of biobased materials developed by SKZ compared to standard PVC-p, used for the toys production. Hardness (Shore D) 45 40 35 30 25 20 15 Bio alternative 1 Bio alternative 2 PVC-p 400 350 300 250 200 150 100 Young‘s modulus (MPa) Introduction Vinyl chloride polymer (PVC) has grown to be one of the major plastics of the world and is the third most important polymer with regard to its production volume. For soft PVC (PVC-p) plasticizers from renewable resources have been developed and are increasingly used. Nevertheless, the petrochemical based PVC matrix mostly remains the same. In cooperation of SKZ (Würzburg), Tecnaro (Islfeld), Schleich (Schwäbisch Gmünd) and Konrad Hornschuch (Weißbach, all Germany), sustainable alternative materials for PVC-p on the basis of renewable raw materials have been developed. To achieve this goal various bio based polymers were modified in a way that flexible materials with comparable characteristics to PVC-p were obtained. The materials are to be used predominantly for manufacturing of toys and table coverings. Formulations and Process In the course of the project, different bio based compounds were developed, which can be used as alternative materials for PVC-p. These materials consist of commercially available (PHB-based) biopolymers, biobased plasticizers, inorganic fillers as well as different additives (see Table 1). The compounds were prepared by melt mixing on a corotating twin-screw extruder Leistritz ZSE27Maxx (L = 1,188 mm and D = 27 mm). To be able to incorporate a large amount of plasticizer in the polymer matrix, a suitable screw configuration was designed. All components were dosed gravimetrically. The extruded strands were passed through a water bath and transported to pelletizer using a conveyer belt (see figure 1). After compounding, the pellets were air dried at 80 °C for 4 h in a Motan-Colortronic drying chamber, type Luxor 50 and injection moulded into plates 150 x 100 x 2 mm 3 using a Battenfeld TM 1300 machine. Material Properties The test samples were cut from injection moulded plates. Weight loss after storage for 7 days at 70 °C as well as Shore D hardness and tensile properties according to DIN EN ISO 527 (Young’s modulus, tensile strength and elongation at break) were determined. The comparison of the bio based materials developed by SKZ with the standard PVC-p used for toys production is presented in figure 2 and 3. The biobased materials for toys manufacturing developed by SKZ show a lower hardness, a slightly higher Young’s modulus as well as considerably higher elongation at break compared to conventional PVC-p. 24 bioplastics MAGAZINE [04/16] Vol. 11
Toys By: Nikola Kocić, Martin Bastian, Bernhard Ulmer, Marieluise Lang, Peter Heidemeyer German Plastics Center SKZ Dirk Schawaller, Michael Schweizer, Helmut Nägele Tecnaro GmbH A slightly lower tensile strength of the biobased materials can be compensated through adaptation of the part design. The amount of renewable raw materials (without filler) in the developed compounds is approx. 64 wt.%. The materials exhibit good processability regarding injection moulding with the processing temperature being 50 °C lower than that of PVC-p. This considerably reduces the energy consumption and the related production costs. Additionally, toys made of biobased materials showed good results regarding coloring. The first demonstrator toy, the horse “Falabella”, was produced by Schleich GmbH and directly coloured under serial conditions. The result is presented in figure 4. Based on the results obtained by SKZ, the upscaling trials were performed by Tecnaro GmbH. In scope of these trials, further biobased materials (special grades of Arboblend) with special consideration of the economic aspects were developed. The mechanical and thermal properties of the biobased materials obtained by Tecnaro are equal to that of the commercial PVC-p materials. Furthermore, the new biobased materials show better thermal resistance than PVC-p. The paintability as well as the paint adherence of the injection moulded toys made of Tecnaro’s biobased materials were examined and confirmed. As example, the demonstrator toy „Tigerjunges“ produced and painted by Schleich GmbH are shown in figure 5. The project is conducted in the framework of the program “Biobased Polymers and Biobased Natural Fibre Reinforced Plastics” of the German Federal Ministry of Food and Agriculture and financially supported via the Agency of Renewable Resources (FNR).. www.skz.de Bernd Kugler Schleich GmbH Frank Waiblinger Konrad Hornschuch AG Figure 3: Elongation at break and tensile strength of biobased materials developed by SKZ compared to standard PVC-p, used for the toys production. Elongation at break (%) 350 300 250 200 150 100 50 0 Bio alternative 1 Bio alternative 2 PVC-p 70 60 50 40 30 20 10 0 Tensile strength (MPa) Figure 4: Horse „Falabella“ made by Schleich GmbH using the biobased materials developed at SKZ Figure 5: „Tigerjunges“ made by Schleich GmbH using the bio based materials developed by Tecnaro GmbH bioplastics MAGAZINE [04/16] Vol. 11 25
