Hello and welcome to a new rule of thumb post. Today we discuss how to select the optimal PET grade (fiber vs sheet vs bottle grade) for your application.
Figure 1: Selecting the optimal PET grade
PET Intrinsic Viscosity (IV; dL/g) as a Key Indicator for selection and quality
Polyethylene terephthalate, or PET, is a ubiquitous polymer in our daily lives, from clothing to packaging. But not all PET is created equal. The key to its diverse applications lies in its Intrinsic Viscosity (IV), a crucial measure of its molecular weight and, consequently, its strength and processing characteristics. This is especially vital when utilizing recycled PET.
Application-Specific IV Ranges
For yarn and fiber applications, where flexibility and drape are paramount, PET with an IV between 0.6 and 0.7 dL/g is preferred. Moving up the scale, 0.7 to 0.8 dL/g PET is ideal for sheet applications, offering the necessary rigidity for thermoforming.
The familiar PET bottles we see daily, typically created through injection moulding into preforms, require an IV of 0.8 to 0.85 dL/g to ensure robust performance. For demanding uses like water jerry cans, where extreme durability is essential, PET with an IV greater than 0.85 dL/g is selected.
Summary of the PET IV ranges:
Yarn & Fiber (0.6-0.7 dL/g)
Sheet (0.7-0.8 dL/g)
Bottle (0.8-0.85 dL/g)
Jerry Cans (> 0.85 dL/g)
Choosing the correct IV grade is fundamental for achieving optimal product performance and ensuring efficient processing, highlighting why precise PET grade selection is critical for quality and sustainability across industries.
Hello and welcome to a new blog post in which we discuss the benefits of incorporating Life Cycle Assessment (also referred to as Life Cycle Analysis; LCA) into your plastic product design.
What is a LCA and why is it important?
LCAs are part of the holistic Life Cycle Engineering (LCE) approach and quantify the environmental impacts of plastic products across all stages of their life cycle, including raw material extraction, manufacturing, transportation, use, and disposal or recycling. One can analyze "cradle-to-cradle", where the end of a lifecycle is taken as the end of the recovery process or focus only on "cradle-to-grave", where the end of lifecycle is the disposal of post-consumer plastic waste. In addition, there is also "cradle-to-gate", where the end of lifecycle is taken to be delivery of the product at your factory gate (Figure 1). Altogether, a LCA provides a comprehensive picture of the overall environmental burden associated with a plastic part, allowing designers to identify areas where improvements can be made.
There are two major standards helping to bring a LCA to reality:
ISO 14040: providing the principles and framework.
ISO 14044: provides the roadmap on how to make the LCA. It provides information on the four steps a LCA should contain in order to systematically be able to quantify the environmental impact.
Figure 1: Overview of Polymer Life Cycle Engineering (LCE) and Life Cycle Assessment (LCA).
What are the four stages of a LCA?
Following is a brief description of the four stages of a Life Cycle Assessment (LCA), which should help you understand the process (Figure 1):
1. Goal and Scope Definition: This initial stage defines the purpose and breadth of the LCA study. It clarifies the product system being assessed, its functions, the intended application of the results, and the audience. This step also outlines the system boundaries, functional unit, and data quality requirements.
2. Life Cycle Inventory (LCI): This stage involves collecting data on all inputs and outputs associated with the product system. This includes raw material acquisition, energy consumption, manufacturing processes, transportation, use phase, and end-of-life treatment. The LCI aims to quantify all relevant environmental exchanges, such as resource use and emissions.
3. Life Cycle Impact Assessment (LCIA): In this stage, the environmental impacts associated with the inventory data are evaluated. The LCIA aims to translate the LCI results into environmental impact categories, such as climate change, ozone depletion, acidification, eutrophication, and resource depletion. Different LCIA methods are available, each with its own set of impact categories and characterization factors.
4. Interpretation: The final and crucial stage involves analyzing the LCI and LCIA results to draw conclusions and make recommendations. This stage assesses the significance of the results, identifies key environmental issues, and evaluates the consistency and completeness of the study. The interpretation should provide clear and transparent conclusions that address the defined goal and scope of the LCA.
The single stages can be supported by software solutions such as GaBi (Sphera) or Echochain.
What are the benefits of incorporating LCA into your plastic product design?
Currently, over 80% of the product's environmental impact is determined at the design stage. Integrating Life Cycle Assessment right from the design phase of plastic products can unlock some really significant advantages. Here are five key benefits for you to keep in mind:
1. Reduced Environmental Impact: LCA allows you to identify environmental hotspots and by considering the entire life cycle – from raw material extraction to end-of-life disposal – during design, you can actively choose materials and processes that minimize environmental burdens. This includes lower greenhouse gas emissions, reduced water and energy consumption, and decreased waste generation. For example, opting for recycled plastics or designing for easier recyclability can significantly lessen the environmental footprint.
2. Enhanced Resource Efficiency: LCA encourages designers to think critically about material usage and optimize product design for longevity and repairability. This can lead to using less material overall, extending the product's lifespan, and facilitating component reuse or remanufacturing. Think about modular designs that allow for easy replacement of worn-out parts rather than discarding the entire product.
3. Cost Optimization: While the initial LCA might involve some investment, it can lead to significant cost savings in the long run. By identifying resource-intensive stages or materials with high price volatility, designers can explore more cost-effective alternatives. This could involve using less expensive but equally functional materials, replacing metal by high performance polymers, streamlining manufacturing processes, or designing for efficient logistics and waste management.
4. Improved Product Performance and Innovation: The insights gained from an LCA can actually spark innovation and lead to better-performing products. Understanding the environmental constraints and material properties throughout the life cycle can drive the development of novel polymeric materials, innovative designs for durability and functionality, and even new business models like product-as-a-service.
5. Stronger Brand Reputation and Stakeholder Engagement: In today's environmentally conscious world, companies that demonstrate a commitment to sustainability through practices like LCA often build stronger brand loyalty and attract environmentally aware consumers. Transparently communicating the environmental performance of products based on LCA findings can also enhance engagement with stakeholders, including investors, regulators, and the wider community.
6. Informed Decision-Making: By providing a quantitative assessment of environmental impacts, LCAs help designers make more informed choices about polymer material selection, design features, and end-of-life strategies. This can lead to the development of more sustainable plastic parts with a reduced environmental footprint.
7. Comparing Alternatives: LCAs can be used to compare the environmental impacts of different plastic types, manufacturing processes, and end-of-life management options, helping designers choose the most sustainable approach. This can lead to the development of plastic parts that are not only functional but also environmentally responsible. As an example, Figure 1 compares the Global Warming Potential (GWP) and density of different plastics.
8. Supporting Circular Economy and Waste Reduction: LCAs are valuable tools for promoting a circular economy for plastics by helping to identify opportunities for reuse, recycling, and remanufacturing. By understanding the full life cycle of a plastic part, designers can create products that are more easily recycled or repurposed, reducing waste and promoting a more circular approach to plastic production.
Example of a LCA: Packaging
A LCA was done on 10,000 units of 12oz packages produced in different materials in the United States [10]. In the stage four, (interpretation), a contribution analysis was done, in order to understand the Global Warming Potential (GWP) of the different packaging materials. This in turn allows for better decision making, when the aim is to reduce the product carbon footprint of the packaging material.
Figure 2 presents the comparison of the GWP of aluminum can, glass bottle and PET bottle. By switching from glass bottle to PET-bottle, a 50% reduction in GWP can be achieved.
Figure 2: Comparison of GWP of a 12oz bottle made out of glass, aluminum and PET [10].
Conclusion
In conclusion, LCAs are essential tools for promoting sustainable plastic part design by providing a comprehensive and quantitative understanding of the environmental impacts associated with plastic products throughout their life cycle. By using LCAs, designers can identify hotspots, make informed decisions, and develop more sustainable and eco-friendly plastic parts that contribute to a circular economy and a healthier planet.
Often, a full LCA is not needed, it is better to make a simplified one and focus on one or two key outputs, than to have no LCA done at all.
Want to deep-dive into designing a sustainable future with polymers? Check out my talk on this topic:
Curious about how Life Cycle Assessment can revolutionize your plastic product design process? Do you have questions about its implementation or the benefits it can unlock? I'd love to hear from you. Contact me here to start a conversation and discover the possibilities.
Hello and welcome to a new post and today I present to you 4 tips for effective polymer material selection. In the realm of plastic product development and engineering, the selection of the appropriate polymer material stands as a pivotal decision, directly influencing the functionality, durability, cost-effectiveness, and overall success of the final product.
Navigating the vast landscape of available plastics and their diverse properties can feel like traversing a complex terrain. To ensure optimal outcomes, a structured and thoughtful approach is paramount. This guide illuminates four essential tips that will empower engineers and designers to make informed and effective polymer material selections, laying the groundwork for robust and reliable applications.
Let us geht started!
1. Requirement Analysis
Map out the true part functions, load cases, and material requirements.
Consider industry standards for properties like flammability, thermal, and electrical characteristics.
Include qualitative properties such as haptic perception and optical qualities.
These tools provide documentation and help understand decisions made by others.
Conclusion
Mastering the art of polymer material selection is an ongoing process of learning and refinement. By diligently applying these four tips – thorough requirement analysis, insightful questioning, maintaining a resin-neutral perspective, and leveraging decision-making tools – you can significantly enhance the effectiveness of your material choices. Embracing this structured approach not only leads to better performing and more cost-efficient products but also fosters a deeper understanding of material science and engineering principles within your team. Ultimately, the thoughtful and informed selection of polymers is a cornerstone of innovation and a key driver in creating successful and sustainable solutions for a wide range of applications.
Ready to begin your journey to Polymer Mastery? Take the Polymer Material Selection scorecard today and discover your POMS score!
Hello and welcome to this new post, today in the theme of Star Wars, together with polymer material selection.
FindOutAboutPlastics.com presents: The Path to Polymer Selection Mastery - A Jedi's Journey.
The path to becoming a master of polymer material selection is a challenging one, requiring dedication, perseverance, and a deep understanding of the Force, or in this case, the properties of plastics. Just as a Padawan must undergo rigorous training and face numerous trials to become a Jedi Knight, so too must an aspiring polymer engineer navigate a series of challenges to master the art of material selection.
This journey begins with a thorough understanding of the fundamental principles of polymer science, including the various types of polymers, their structures, and their unique properties. It is akin to a Padawan learning the basics of lightsaber combat and the Force. From there, the aspiring engineer must delve into the intricate details of polymer behavior, exploring how different polymers react under various conditions, such as heat, stress, and chemical exposure. This is similar to a Padawan mastering the subtle nuances of the Force, understanding its power and limitations.
The next step involves applying this knowledge to real-world applications, selecting the most suitable polymer for a specific purpose. This is where the true test of skill lies, as the engineer must weigh various factors, such as cost, performance, and environmental impact, to make the optimal choice. This is analogous to a Jedi Knight facing a dangerous mission, where they must use their knowledge and skills to overcome obstacles and achieve their goal.
Finally, the journey culminates in mastery, where the engineer can seamlessly integrate their knowledge of polymer science with their understanding of engineering principles to create innovative and sustainable solutions. This is akin to a Jedi Master, who has achieved enlightenment and can use the Force for the greater good.
In essence, becoming a master of polymer material selection is a continuous learning process, requiring a combination of theoretical knowledge, practical experience, and a deep understanding of the challenges and opportunities that lie ahead. It is a journey that demands dedication, perseverance, and a willingness to embrace the unknown, just as it does for a Padawan seeking to become a Jedi Master.
The path to polymer mastery may be arduous, but the rewards are great. Those who persevere will gain the ability to shape the future, creating products that are not only functional but also sustainable and beneficial to society. So, embrace the challenge, hone your skills, and embark on your journey to polymer mastery.
Ready to begin your journey to Polymer Mastery? Take the Polymer Material Selection scorecard today and discover your POMS score!
