Quo vadis, plastic?
No other material, coupled with the environmental problems it causes, is the subject of such controversial debate as plastic is. However, no other material is as versatile and essential. Therefore, environmental issues are currently top of the agenda as far as plastics production and finishing are concerned.
Trends in this industry reflect the major global issues in microcosm. According to the 2019 World Economic Forum, the world’s top three risks are environmental ones - extreme weather, a lack of climate policy progress and natural disasters. 1000 economic, political and civic society experts are agreed on that point. The top 3 are followed in fourth and fifth place respectively by data theft and cyberattacks. When applied to the plastics industry, the priorities are very similar - recycling, the circular economy (closed-loop materials management) and environmental issues are right at the top of the agenda, followed by energy efficiency and Industry 4.0. Furthermore, the industry has recognized that it has an image problem. Littering of the seas, microplastics in food and other negative headlines have discredited a material that, if used and disposed of properly, provides a large number of benefits and is often irreplaceable.
Manufacturers’ options for taking action
What can and should be done? The industry only has limited scope of action as far as the disposal of packaging is concerned. In contrast, it can have a direct impact on plastics production and processing.
In this respect, appropriate measures include:
- substitution of fossil through renewable resources,
- reduction in plastics quantities through efficient production processes,
- return of reject and waste materials into production processes,
- use of recycled materials,
- proactive design of recycling processes,
- provision of information to the public through studies and industry association activities.
PLA made from starch is 100 percent bio-based and degradable.
Bioplastics provide new opportunities
Problem recognized and action taken? Renewable raw materials and biotechnology processes are gaining importance in the industry. In fact, the bioplastics family is huge – it is split into those that are made of renewable raw materials and those that are biodegradable, and includes the group of materials that provide both benefits. Some bioplastics are capable of replacing conventional ones, while others feature new properties and therefore increase choice.
Bioplastics – an overview:
- (Partly) biobased, non-biodegradable plastics: polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), high-performance technical polymers, such as polyamide (PA), polytrimethylene terephthalate (PTT) or (partly) biobased polyurethane (PUR)
- Biobased and biodegradable plastics: polylactic acid (PLA), polyhydroxyalkanoates (PHA), polybutylene succinate (PBS) and starch blends
- Fossil-based, biodegradable plastics: polybutylene adipate terephthalate (PBAT)
Moving away from fossil-based raw materials
For the most part, bioplastics are not dependent on fossil resources and are capable of reducing the carbon footprint considerably – in particular in combination with recycling and closed-loop materials management, says industry association European Bioplastics. Many biobased polymers are equivalent substitutes for conventional plastics. For example, these include polylactide (PLA), which is derived from fermented starches and sugar, as well as biobased polyethylene terephthalate (BioPET) and polyethylene (BioPE).
The raw materials for these polymers include sugar cane and bioethanol (source: Wuppertal Institute). First innovations, like compostable PLA, PHA and PBS, are even exhibiting new, enhanced properties. Brand new materials like polyethylene furanoate (PEF) exhibit better barrier properties than established polymers and, what is more, can be easily recycled. Below is a table with a detailed description of these new materials.
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Modifications to production processes
As far as production is concerned, new materials entail the development of new processes. The flow properties of these alternative bioplastics exhibit different characteristics to conventional pellets. Component manufacturers like Kubota Brabender Technologie can assist producers here – newly developed products can be tested at its in-house Technical Center and the appropriate feeder in each case can be selected and then configured. In some cases, these new materials also require production innovations – Brabender Technologie is always geared up to undertake technical enhancements.
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Recycling within the production environment
Even bioplastics do not obviate the need for recycling. They too have to be included in a reusable material cycle, as they are not necessarily biodegradable. The logistical challenge of recycling both conventional and alternative plastics is significantly less to an industrial business than it is when consumer waste is involved. Manufacturers frequently know exactly what their production waste consists of, and it is to some extent even homogenous or mono-material. Reject components, like injection-molded parts, can therefore be returned really easily to the production process. First of all, they are shredded then milled; the ground material is then homogenized in an extruder and processed into strand-shaped pellets. The resultant recycled pellets can however exhibit differing properties to the source material.
Our special FiberXpert fiber feeder is particularly ideal for challenging materials like carbon fibers, which result from recycling films.Bernhard Hüppmeier, Head of Business Development, Kubota Brabender Technologie
Another example is processing film edge trimmings. When films are manufactured, their edges are straightened at the end of the process, meaning some waste is unavoidable. This material is difficult to handle and therefore often has to be processed into pellets, before it can be added back into the production process. In collaboration with its partners, Kubota Brabender Technologie has developed technologies like the FiberXpert feeder, which feeds these film edge trimmings directly after shredding and conducts them to the extruder.
Keeping an eye on energy-saving potential
Energy costs account for a very high percentage of process costs in this industry. In an age of rapidly rising energy prices, cost-saving measures are on the agenda of practically every company. Examples of this are processes in which waste material is refed directly back into the production process, without involving an intermediary treatment process.
Another example are carbon fibers, which can be obtained from carbon fiber-reinforced plastics by means of pyrolysis and reused. These fibers tend to clump together, are contiguous and also have a very low bulk weight. The above-mentioned FiberXpert, the perfect solution for feeding these challenging materials, was developed specifically for these kinds of materials. The idea behind this product innovation is to save the additional process and energy costs involved in the treatment process, as well as transport and administrative costs.
Savings through enhanced process control systems
However, the priority in control system terms is being able to synchronize processes better in order to avoid leftover materials. One example of this is just filling a weigh-feeder to a level where as little non-required material as possible remains at the end of a batch, or maintenance intervals are identified as early as possible (predictive maintenance). Such integrated processes are challenging and can make major demands of control systems. Kubota Brabender Technologie meets these requirements and unveiled an OPC-UA interface at K 2019, the purpose of which is to analyze process and feed data at the customer’s facilities. “Industries will be able to keep much better track of their equipment in the future and coordinate processes and maintenance accurately, especially given the new 5G cellular network standard,” states Bernhard Hüppmeier, Head of Business Development at Kubota Brabender Technologie.
Bioplastics provide new opportunities
Are you considering how you can incorporate bioplastics into your production process? Contact Bernhard Hüppmeier, Head of Business Development
