vor 8 Jahren

02 | 2010

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Rigid Packaging

Rigid Packaging Thermoforming High Heat Products Custom thermoformer, Plastic Ingenuity, Cross Plains, Wisconsin, USA, a national leader in the light gauge custom thermoforming industry since 1972, has been and continues to lead the industry with its unparalleled innovation and R&D. Now they have developed a proprietary process improvement that significantly increases the heat deflection temperature in PLA (Polylactic Acid) material, clearing a significant hurdle regarding this sustainable material. This advancement includes a material enhancement and unique processing techniques to attain higher temperature PLA. Stock versions of PLA material could only withstand temperatures of 45°C (110 F) before the integrity of the part became compromised. This was a major issue regarding transportation, especially during summer months and in warmer climates where the temperature can easily surpass 45°C in unconditioned environments. Plastic Ingenuity has formed PLA parts that have heat deflection temperatures of 93°C (200 F) with no apparent ill effects after rigorous trials and studies, giving the material better heat stability than PET and comparable to HIPS. “To our knowledge we are the first thermoformer in the industry to have attained heat deflection temperatures at these levels, and we have a vast array of studies to support these claims,” said Bob Whitish, Project Engineer at Plastic Ingenuity.“To date, we have sampled over 200 new and different bio-materials/bio-material combinations. It is our goal to find multiple bio-based materials that will meet the requirements of a multitude of packages whether their vital characteristic is clarity, impact strength, heat deflection resistance or any of a variety of other characteristics,” he said. With the global emphasis on sustainable, environmentally friendly solutions, Plastic Ingenuity’s ability to thermoform a high heat deflection PLA gives customers a viable alternative to petroleum based packaging. PLA is derived from corn, and is biodegradable and compostable per EN13432 (ASTM D6400) industry standards. Aside from PLA, significant advancements have come when dealing with PSM. Plastarch Material (PSM), used for a multitude of products, is a biodegradable, thermoplastic resin derived from more than 80% cornstarch that is modified to produce high heat-resistant properties. The high heat tolerance of PSM makes it a good fit for such applications as thermoforming, injection molding, blown film, and foaming. Also, it can be disposed of through incineration, resulting in a nontoxic residue that can be used as fertilizer. Companies that produce this material, like Plastic Ingenuity, also use 100% bioadditives in the product to ensure its quality and sustainability. 16 bioplastics MAGAZINE [02/10] Vol. 5

Rigid Packaging Short wave infrared emitters from Heraeus Noblelight optimise deep drawing processes and reduce reject rates. Infrared Heat for Corn Starch Packaging Sweets, chocolates and other types of confectionery are packed in boxes with plastic insert trays. These trays are manufactured by thermoforming plastic sheet. A relatively new development is to produce the inserts in bioplastic. Infrared emitters from Heraeus Noblelight, Kleinostheim, Germany, are now being used by Plantic Technologies Germany in Schorba, Germany to thermoform bioplastics. These emitters transfer energy without contact and generate the heat predominantly in the material itself. As a result, heating is targeted and fast. The thermoforming process is optimised and reject levels are reduced. Australian Plantic Technologies Ltd has developed and patented a bioplastic made of vegetable starch from non-genetically modified maize. This cornstarch is used to manufacture trays, blisters and sorting inserts in chocolate packaging. To do this, the foil must be heated and then thermoformed. Normally, using conventional plastic foils, this takes place in several stages, each involving a few seconds of heating, until the deformation temperature is achieved. However, properties such as strength, flexibility and stability of the cornstarch foil can be detrimentally affected by long heat-up times. This is because moisture can evaporate from the foil in the heating process and can lead to it becoming brittle. In collaboration with Heraeus, Plantic investigated several possibilities in an effort to optimise the heating process. Short wave emitters demonstrated that they were particularly suitable for the task, as, using high power, they could bring the foil to the deformation temperature of around 140ºC in approximately two seconds. This is so fast that there is virtually no moisture loss. A heating module with overlapping emitter ends and several heating zones ensures a homogenous temperature distribution across the foil. Consequently the thermoforming process for cornstarch foils is optimised, and it has also been shown that reject rates at process start-up can be minimised. Infrared emitters transfer energy without contact and generate heat only in the material to be heated. Short wave infrared emitters offer response times of the order of seconds, so that control is excellent. They transfer heat rapidly and at high power. Infrared emitters need to be switched on only when heat is required, thus saving energy. Heraeus Noblelight offers the complete range of infrared heat from short wave NIR to medium wave carbon infrared CIR. Heraeus calls on more than 40 years experience of infrared emitters. In its in-house application centres the company carries out practical tests and trials with customers’ own materials to identify the optimum process solution. bioplastics MAGAZINE [02/10] Vol. 5 17

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