Finally there are a number of plastic-specific DfR guidelines to consider when designing a product:

• Use common plastics only (e.g. ABS, PE, PP, PA, PC , PC/ABS and HIPS)
  Unlike uncommon plastics, these materials are already being recycled in sufficient volumes. If an uncommon plastic is necessary, use one with a density outside the 0.85 – 1.25  g/cm³ density range of common plastics.
• Avoid polymer blends
  Polymer blends (besides PC/ABS) can pollute recycled material streams.
• Avoid glass fibre filled polymers
  Glass fibres pollute the recycled material stream and can decrease its mechanical properties.
• Minimise the use of additives
  These reduce the purity of recycled plastic streams.
• Avoid the use of thermoset rubbers
  These cannot be recycled.
• Avoid the use of thermosets and composites
  Thermosets cannot be recycled. If a thermoset is required, use one with a density outside the 0.85 – 1.25 g/cm³ density range of common plastics.
• Avoid coatings and paints on plastic parts
  They will pollute material streams and possibly change the density of the material.
• Avoid the use of foam
• Minimize the use of thermoplastic elastomers
  These are not recycled.
• Do not use plating, galvanizing or vacuum metallization to coat plastic parts
  This creates a connection between the plastic and metal.

Source: Design for and from Recycling: Practical Guidelines for Designers (PolyCE, March 2021)