Main Takeaways
- The properties of recycled plastics are improved through compounding: i.e. blending in additives or virgin polymers.
- Recycled plastics are likely to contain legacy additives and contaminants that affect the material’s quality. The material will also have degraded during previous use and processing.
- Recycling affects a plastic’s mechanical properties (e.g. density, tensile strength, elasticity, brittleness and viscosity) and aesthetic properties (e.g. colour, odour, surface finish).
- These properties can be improved by blending in fillers and additives such as thermal stabilisers, UV absorbers and impact modifiers.
- Yet additives may themselves make the material more difficult to recycle in the future. Therefore, try to limit their use whenever possible.
VIDEO PEZI GROUP
DROP-IN METHOD
- Complexity level Tool
- Is this type of plastic available in recycled grade?
- Are there any legal limitations?
- What are the visual requirements?
- What are the Critical to Quality requirements?
Based upon this the parts are rated from 1 to 4.
- 6 steps to material approval
- Look & Learn
Finding the balance between the properties of rPlastic. (Brittle vs impact resistance)
Main Takeaways
- The ‘drop in method’ is a step-by-step process to learn about, and then apply, recycled plastic grades. It consists of three pillars.
- The complexity level tool helps to analyse which of your product’s parts are the easiest to manufacture with recycled plastics.
- The six steps to material approval pillar helps to gradually build confidence in the application of recycled grades into your product.
- The look and learn pillar is about creating samples, or demonstrators, to learn about the aesthetic and mechanical properties and remove uncertainties about the recycled material’s behaviour. Start with existing moulds so you can compare parts made from recycled and virgin plastics.
- Once the knowledge gap about the material is filled it becomes possible to design entirely new products with it.
As Thijs Feenstra explained on the previous page, the complexity level tool can help to get started with applying recycled plastics. You can use it to evaluate a product or even an entire product portfolio to identify plastic parts that have relatively low requirements (mechanical, aesthetic, etc.). This means they are easier to manufacture out of recycled plastics.
The tool distinguishes between four complexity levels (as seen in the image below). ‘Level one’ parts are considered the easiest to make with recycled plastics, while ‘Level four’ parts are currently considered too complex.
Complexity levels within the drop in method. Source: PolyCE.
You can determine the complexity level of any part by answering the following questions and then looking at the flowchart that is shown below.
- Is the type of plastic available in a recycled grade (i.e. a target group plastic)?
- Are there any legal limitations? (Product compliance).
- What are the visual requirements?
- What are the critical to quality (CTQ) requirements?
As you can see, the requirements on the right have different colours that correspond with the four complexity levels.
