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Issue 06/2017

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  • Bioplastics
  • Biobased
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bioplasticsMAGAZINE_1706

Polyurethanes/Elastomers

Polyurethanes/Elastomers Injection molders who have made bioplastics work Summary Bioplastics have a problematic reputation among injection molders because running them in the past has been - in some cases - both cumbersome and expensive. However, many modern bioplastics do not exhibit the troubling qualities of their predecessors and can now run through the injection molding process similarly to traditional petroleum-based plastics. The author spoke with four injection molders in North America who have successfully worked with bioplastics to gauge their thoughts on the material’s performance. How has the relationship between injection molders and bioplastics changed? Injection molders have had issues with bioplastics in the past because certain materials were expensive and not compatible with existing equipment. These issues forced injection molders at times to purchase new equipment and even make fundamental and expensive changes to their processes. As a result, bioplastics now have a problematic reputation among injection molders, who are wary of using them in their facilities. However, bioplastics have since evolved and most of them can now seamlessly replace certain traditional petroleumbased plastics. The four interviewed injection molders provided valuable and promising insights on what working with bioplastics entails. Although each had technical issues at the initial stages, they were eventually able to run the materials successfully in their respective facilities. Matt Poischbeg, an injection molder at Sea-Lect Design (Everett, Washington, USA), was enthusiastic about experimenting with different bioplastics due to the possible competitive advantages they could offer to customers. He found out about Green Dot Bioplastics five years ago at an outdoor retailer expo in Salt Lake City, Utah, USA. Poischbeg said the company caught his attention because he “…was amazed that they had a flexible compostable plastic.” He had heard of compostable biodegradable plastics but had never seen elastomeric materials. Poischbeg experimented with the flexible compostable plastic material for kayak manufacturers but had to forgo the project due to a lack of demand. However, he successfully developed a compostable luggage tags for Pearl Jam with Green Dot Bioplastic’s Terratek Flex (a biodegradable elastomer) and Terratek BD (a biodegradable bioplastic) and is eager to continue experimenting with different materials. Poischbeg’s enthusiasm parallels the prediction made by the European Bioplastics Association (source: Plastics Today) that biobased and biodegradable plastics will see an increase in global demand. Should injection molders experiment with bioplastics? While it is understandable why companies want to stick with established plastic materials, experimenting with new ones can be rewarding. Hal Alameddine, the President of Pike’s Peak Plastics (Colorado Springs,Colorado, USA), successfully worked with a Terratek Biocomposite composed of bio-based polyethylene derived from sugarcane and corncob fibers to develop Eco-Rigs for Begin Again Toys, which was licensed by John Deere. Alameddine said, “It’s a good material to run. We didn’t feel that we needed to make major adjustments to our current process with respect to running standard polyethylene. This one was a little trickier because of the addition of the corncob into it. But in general, I would say it ran as well as any other material.” Initial challenges are not uncommon. Reed Hardgrave, an injection molder at Ferguson Production (McPherson, Kansas, USA), initially experienced some difficulty with bioplastic resins expressing desirable end properties. However, he eventually found success with a wood plastic composite used to mold toys, replicating the aesthetics of wood. Technical considerations Injection molders who are apprehensive about the compatibility of bioplastics with existing equipment can be confident that most modern materials don’t require any inconvenient specifications. Kevin Godsey, an injection molder at Mid-Continent Tool and Molding, Inc. (North Kansas City, Missouri, USA), made compostable dog-waste dispensers with a starch-based elastomer. He emphasized that although a lower temperature profile was required for the heatsensitive elastomers, the adjustments weren’t beyond standard protocol. In fact, cycle times fell within the norm and even the drying times, which have been a pain point for injection molders, weren’t an inconvenience since he only had to account for surface moisture. Despite having initial challenges, Godsey stated that the material was still “moldable and very user friendly.” What are some of the benefits of working with bioplastics? Based off of the experiences of the injection molders the author spoke with, it is clear that the right bioplastic can be molded with minimal technical issues. Hence, it could be productive for injection molders to at least experiment with different bioplastic resins so they can determine for themselves if the materials are in fact user friendly. 24 bioplastics MAGAZINE [06/17] Vol. 12

Polyurethanes/Elastomers By: Kevin Ireland Communications Manager Green Dot Bioplastics Cottonwood Falls, Kansas, USA Injection molders should think about experimenting and potentially working with bioplastics because: • Most modern bioplastics can be seamlessly incorporated into the injection molding process and no additional equipment is needed to accommodate the materials. • They could diversify options for their customers, especially since Grand View Research (San Francisco, California, USA) found that bioplastics are projected to control 5 % market share of the plastics industry by 2020. • Bioplastics provide customers with unique advertising opportunities since many materials offer unique performance properties and – in addition – sustainability advantages. Small learning curve Although most bioplastics are compatible with existing molding equipment and processes, injection molders still need to experiment with different materials to figure out technical details such as cycle and drying times. Of course, this means the initial stages won’t be perfect. However, each of the interviewed injection molders emphasized that the learning curve was not steep and that they were ultimately able to run the materials with minimal hitches. For example, Godsey noted that scrap rates were somewhat high at the initial stages but quickly got them back within a standard ratio. When we asked Hardgrave if he had issues integrating bioplastics into his current operation, he noted that “venting is a big one. If [bioplastics] don’t vent, plating can become blackened.” Ultimately, Hardgrave was able to overcome his venting challenge and made accommodations for it whenever he was working with bioplastics. Injection molders can now confidently experiment and eventually work with many different bioplastics and many are optimistic about the demand of the materials in the coming years. www.greendotbioplastics.com Photo: Courtesy BeginAgain bioplastics MAGAZINE [06/17] Vol. 12 25

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