Begin with the part and the process
A request for recycled PP or HDPE identifies a polymer family, but leaves many purchasing decisions unresolved. Explain what you are making, how you intend to process it and which requirements are essential. Injection moulding, blow moulding and extrusion can call for different material characteristics within the same family.
Provide an existing specification, an incumbent grade reference or a description of the problem you are trying to solve. Separate requirements that are fixed from those that can be explored through a trial. This allows alternatives to be assessed against a useful brief rather than selected on appearance or headline price.
Define the properties that affect the application
Specify colour, form and relevant physical or mechanical properties, with units, test methods and acceptable ranges where you have them. Identify any limits for moisture, contamination or fillers. If recycled origin or a minimum recycled-content level is required, state the evidence you need alongside the material requirement.
Storage and drying deserve attention. PET, polyamide and polycarbonate are examples of polymers that can absorb moisture from the air. A material that looks dry may still need controlled preparation. Ask for grade-specific handling and drying information, rather than applying a single drying schedule to every polymer.
Make melt-flow figures comparable
Melt flow rate, often discussed as MFR or MFI, is measured under a defined temperature and applied load. A number without those conditions is incomplete. When requesting or comparing results, include the method, temperature, load, units and target range.
MFR is commonly reported in grams per ten minutes; melt volume rate is a different measurement. Keep the distinction clear in your brief. Flow data can support material selection and batch checks, but one value does not describe every property of a finished product. Review it alongside the other requirements that matter to your process.
Agree qualification and supply details
Define how a proposed material will be assessed before routine purchasing. Agree representative sampling, any production trial and the evidence needed to accept a batch. Make special-use requirements explicit at the start; a general recycled-polymer description does not establish suitability for food contact or another regulated application.
The commercial brief should be equally clear. Include:
- Trial quantity and expected ongoing consumption.
- Required packaging, labelling and batch references.
- Delivery postcode, timing and unloading arrangements.
- Technical documents and agreed batch information.
- Who will approve the material and any subsequent changes.