Challenges related to the supply of recycled materials
Raw material evaluation
In the polymer industry and particularly in the plastics industry, the potential of a "good" raw material is assessed according to the following four criteria:
• Its solid state performance:
Meaning, the physico-mechanical properties which enable to meet the specifications of the finished product.
• Its behavior in the molten state:
Meaning, the rheological properties which will define its ease of being manufactured, in other words its ability to respect the various production constraints as well as the desired production rates.
It should be mentioned that among the production constraints are included all the standards and regulations in terms of health, safety at work and environmental protection.
• Its accessibility:
Meaning, its accessibility in termes of cost and volume available on the market.
Virgin raw materials
When working with virgin material, the criteria mentioned above do not present any constraints.
Indeed, producers of virgin resins are able to offer their customers ideal materials, modified and optimized in order to perfectly meet their expectations.
To do this, they can modify the molecular structure of the polymers, add additives to them, or even mix polymers with different molecular structures. The materials obtained in this way are called grades.
Each type of thermoplastic (PP, PE, PET, etc.) can therefore have tens or even hundreds of different grades specific to each of the companies that produce them.
The image below shows three different grades of virgin plastic.
Recycled raw materials
In the world of recycled materials, the situation is quite different, particularly in the case of post-consumer and residual materials.
In fact, in the world of recycling, the notion of grade no longer exists.
The first challenge is already to find material with an acceptable level of impurity, but it is obvious that the latter will consist of an unknown mixture of different grades of plastics.
Indeed the only certainty in the recycled materials market is uncertainty.
The lack of homogeneity, reliability, stability, traceability and predictability of the recycled materials market is part of the job. We simply have to learn to deal with this reality and develop solutions to overcome these challenges, and even take advantage of them.
The image below shows bales of recycled plastics as received by industrials.
Materials charter
The solution is simple, it involves selecting and targeting the materials that meet our needs, whatever their origins or their available volumes. In a way, we have to define our own grades of usable materials.
At IPC we call this assessment process:
“The Materials Charter”
It is complex to establish because several factors and parameters must be considered, particularly in terms of:
• Product specifications and associated tolerances (ATs)
• Types of raw material conveying and feeding equipment and their ATs.
• Technologies and processes of production and their ATs.
An absence or a bad charter of materials will certainly lead sooner or later to non-conformity or quality problems and even to the breakdown of production equipment. Several companies have unfortunately gone bankrupt for having underestimated the challenges of sourcing recycled materials.
A material charter would have greatly helped them, but unfortunately companies do not always have the expertise and experience to do so.
So we have decided to offer this service to those who want it.
Below is a Charter of materials comprising 6 evaluation criteria, produced for one of our client.
