Standards Development

Scope

This standard specifies requirements of an atmospheric, pressurised recycling method for plastic and composite materials to differentiate the sustainability advantages from other recognised processes to enhance and emphasise the circularity of processed materials. This standard specifies the different protocols and procedures to be used for evaluating the performance process at each stage, whilst within these protocols it specifies the conditions and parameters the process is to be conducted in.

Future revisions will specify the mechanical property analysis of the material in numerical terms (against virgin material and material from other recycling processes) and the environmental advantages to meet compliance with the standard at the end of each stage.

This standard covers:

a. Definition of the ‘pressolysis’ process and specifically ‘thermo-cyclic pressolysis’

b. Alignment of specific standardized protocols for each stage of the process, notably:

1. Preparation of the samples for recycling machine; setting parameters for:

-a. Time

b. Temperature

c. Pressure

d. Cycle frequency

2. Material recovery and separation

c. In-process testing protocols for process performance

d. Reporting of the data at the end of each stage of testing and the specifications to indicate compliance with the standard.

This standard does not cover:

• Material performance comparisons to other recycling processes

• Recommended energy uses and cost from clean by-products from utilities (heat and water)

• Cost comparisons between different recycling processes

• The suitability or compatibility of the material to be mechanically, chemically or organically recycled

• The life cycle assessment (LCA) analysis of the process comparing to other recycling techniques

• Self-declared claims of recyclability outside the framework of an appropriate standard such as BS EN ISO 14021

This standard is intended to be used by plastic or composite technology manufacturers, recyclers and waste handlers looking to obtain data as to the performance of the sustainability of recycling technology with a view to selecting a recycling process for maximum sustainability and material performance post-process. In addition, this standard provides procedures for testing equipment with a standardized protocol to evaluate process performance for conformance to the standard. In addition, other standards agencies, national laboratories or academic research groups could use the test method described in this standard as a universal baseline methodology of evaluating the processes and recycling media of new technological discoveries within plastics and composites.

Proposed scope;

• Process Parameters and Settings

• Pre-process considerations inc H&S

• Material preparation

• Process parameters

• Further work planned

• Post-process considerations inc H&S

• Proof of process

• Report & studies (appendices)

Purpose

The use of plastics and particularly composite materials has significantly increased over the past decades in many applications. Driven by the need for strength with lightweight capability and strong supply chains, composites have become the material of choice for many product applications.

The result of this widespread use has meant that the end-of-life scenarios of these materials has come under ever-increased scrutiny. There are four major end-of-life scenarios of plastic/composite materials:

- 1. Landfill (with potential leakage into the natural environment)

2. Mechanical recycling (grinding/pelletising/chipping)

3. Incineration/waste-to-energy (Pyrolysis)

4. Chemical recycling (Solvolysis) Whilst well-known standards and/or industry-accepted protocols exist for determining the applicability or performance of the above processes, they all have environmental drawbacks which may consist of:-

• Non-biodegradability into landfill

• High level of GHG generation

• Potential contamination of water stream

• Chemical pollution – including manufacture of solvents

• Damage to the constituent materials • Reduced circularity due to devalue of damaged materials

• Loss of reusable plastic matrix Considering a composite/plastic material; options 1, 2 and 3 and previous standards in option 4 above; have identified guidelines but have not specified sustainability outcomes. In addition, they have sought to pre-determine the type of recovery process, rather than producing numerical criteria associated with the preservation of the material under any recycling process conditions. Currently, recycling processes for plasticised components are classed under 2 main categories:-

• Mechanical recycling (grinding, pelletising, chipping)

• (Thermo) Chemical recycling (solvolysis, pyrolysis, fluidised bed) Whilst effective, neither of these 2 processes are capable of sustainable polymeric material recycling without damage to the base components (commonly carbon or glass fibres). A process exists that can sustainably recycle and recover all of the constituents of a composite material; this however is often incorrectly classed as ‘solvolysis’ as steam (H2O), which is often used as an atmospheric medium, is a chemical formula. Without a new standard to acknowledge this advancement in innovation, the composites and plastics industries are unaware of an atmospheric sustainability process that can not only reclaim the fibres, resins and polymers, it can do so without causing damage and with minimal depolymerisation and degradation.

The purpose of this proposed standard is to acknowledge this pressure-based innovation as an alternative recycling method, separating pressolysis from solvolysis and to show the potential sustainability of ‘Thermo-Cyclic Pressolysis’.

To achieve the objective of this proposal, internationally accepted existing standards in relation to the three key stages of concern with respect to biodegradability in an open-air terrestrial environment do not apply; since composite materials (with glass fibre, carbon fibre (Incl Aramid) and thermoset resins) are currently not biodegradable.

This standard does not specify the origin of the raw materials used in the composite composition. Claims around bio-based content are to be made in accordance with relevant standards. In addition, the future standard will consider the suitability of multiple life-cycle and durability aspects of the post-processed composite material under evaluation; as different established processes affect reusability, performance and number of potential life-cycles.

In time, the standard will recommend a reclassification of sustainability standards to reflect the degree to which sustainability can be accurately assessed by industry.  Currently, a process is classed as recycling if material does not go to landfill. Therefore, pyrolysis and solvolysis processes, although emitting CO2 and using/producing environmentally unfriendly chemicals, are classed as sustainable processes even though they are compromised – and can also damage the high-value fibres they recover.

An advantage for composites of the pressure-based method is that scrap prepreg (pre-impregnated with resin) materials must currently be cured before they can be ground down for landfill (as uncured resin is toxic and is illegal to send to landfill). Thermo-cyclic pressolysis is able to recover both the fibres and uncured resin without being pre-cured.

Key drivers, i.e. safety, new legislation and/or standards (will it provide support for the implementation of existing standards)

Short term, the standard aims simply to acknowledge pressolysis as an alternative method of materials recovery. It will not be seeking to compare to other established methods at this time.

Medium-long term, under a future revision, it will aim to work alongside DEFRA, EA and DfT along with partners and academics to differentiate the effectiveness of technologies that provide sustainability within composites by providing data on the performance of the tested technology under stated conditions. Only by meeting the circularity requirements of the sustainable processing in all stages of this standard is a technology for a given composite material deemed to be compliant. This work should also enable DEFRA to work with HMRC towards a tiered levy system for waste treatment, based on higher levies for larger footprint/environmental impact.