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 June 2005 Feature
Michael M. Fisher, Ph.D., is senior director of technology for the American Plastics Council in Arlington, Va. His responsibilities focus on plastics in the automotive and electrical and electronic markets with an emphasis on future growth and product stewardship issues. Fisher is a member of ASTM Committees D20 on Plastics and F40 on Declarable Substances in Materials and Chairs ISO Technical Committee 61 on Plastics

Standards Development for Reporting of Declarable Substances

Recovering Plastics from End-of-Life Products

Regulations requiring the reporting of chemical compounds that are used to make plastic formulations have arisen in various regions of the world. European Union end-of-life product regulations involving packaging, automotive, and electric/electronic applications are examples of these requirements. Such regulations have the potential for global impact when multinational corporations are involved. To help meet evolving market needs related to declarable substance requirements, a new ASTM International committee, F40 on Declarable Substances in Materials, was formed with input from a broad cross-section of stakeholders, including the chemical and plastics industries.

To best describe the effect of these regulations and to illustrate where standard tests are required it is necessary to understand how plastic materials are selected and flow through the manufacturing process to end-of-life and resource recovery stages. The emphasis in this article is on plastics used in durable goods, such as automobiles and electrical and electronic products, which represent a significant component of global trade.

Plastics are formulated to meet a variety of requirements including, for example, stiffness, ductility, color and durability. These requirements are primarily focused on meeting the use-phase needs of specific applications such as computer housings or automobile bumpers. Over the years, ASTM Committee D20 on Plastics has helped to serve the standards development needs of the plastics industry, emphasizing the critical areas of terminology and material performance testing. Understanding chemical composition issues that can arise during product end-of-life and material recovery stages has begun to define a new set of challenges.

Recovery Considerations

Once a device has reached the end of its useful life, it is either dismantled to recover certain components or shredded to recover its metal content. The large scale commercial shredding operations in place today were developed with a focus on metals recovery and present many challenges to the recovery of a growing proportion of plastic materials. After shredding, the plastics are commingled with dissimilar materials such as residual metals, glass or dirt, and multiple types of plastics are often left mixed together. The latter issue is important because the properties of many plastics are reduced significantly in the presence of other plastics. Mixed plastics exhibit different properties than do individual virgin resins. Since the material’s initial properties were important in the selection of that plastic for a particular end use, the recovered material may be unfit for that application. This results in using the recovered material in other, often less demanding, applications.

The alternative is to separate the mixed plastic into its individual plastics and much progress is being made toward that end. In addition to the separation of plastics, there is the issue of contamination, particularly with chemical compounds or elements that are restricted in commerce in some manner. Polychlorinated biphenyls or PCBs are a classic example. Consequently, depending on material source, there may be a need to determine both the generic identity of the plastic material and the presence of contaminants or additives during the plastics recovery process.

Beginning in the early 1990s, many of these issues associated with plastics recovery from end-of-life products were addressed by ASTM Subcommittee D20.95 on Recycled Plastics. Today, new standards development activity is under way at the national, regional, and international levels reflecting both regulatory and commercial developments in this field.

Substances of Concern

Many substances of concern have been identified by regulatory agencies throughout the world. The heavy metals (mercury, lead, hexavalent chromium, and cadmium), PCBs (207 congeners) and dioxins/ furans are often mentioned. Recently, some types of brominated flame retardants used in plastics have gained attention. Of particular concern are the penta- and octa-brominated diphenyl ethers.
Other substances that may show a potential for health effects are listed, for example, in the “Dangerous Substances” section of EU Directive 67/548 EEC on the classification, packaging and labelling of dangerous substances. Some of the substances are introduced as contaminants as a result of recovery operations. This can occur when different types of end-of-life products are mixed during shredding. In the course of recovering the metals, contamination of the residual plastics can occur, complicating the downstream recovery of plastics.

In the case of flame retardant additives, some FR packages used in the past are no longer being employed commercially; in the case of penta- and octa-polybrominated diphenyl ethers, many of their future uses are being restricted. This has implications for plastics recovery.

Regulations

Examples of regulations governing the presence of certain substances in both the use phase and at the end-of-life for environmental reasons can be seen in the EU directives for packaging, end of life vehicles, waste electrical/electronic equipment and for the restriction of hazardous substances. These regulations in some cases prohibit the use of a few substances and create the need to identify the location of others. Original equipment manufacturers must be able to collect this information in order to identify applications that may require redesign or could require special handling at product end-of-life.

The automotive industry has worked for several years to develop an efficient system to capture this chemical information, and the electrical and electronic equipment industry has a similar initiative under way. These are industry-led initiatives rather than individual company activities. The automotive industry is well along in creating a repository of information on individual vehicles called the IMDS (International Material Data System). This system contains information on substances contained within a material as well as surface treatments used on the materials. The IMDS provides information gleaned from each step of the manufacturing process, from the manufacturer of a plastic resin, to the processor, to subassembly makers, to the large Tier One system integrators. Consequently, a fully implemented IMDS would contain a complete breakdown of a vehicle that shows every part in the system along with compositional information. The information that is relevant to the IMDS relates to the generic material being used and the presence of substances of concern. Through this system the automotive OEM is able to provide specific information on the location and overall amounts of substances in the vehicle as required.

Reporting Declarable Substances

The initial approach to dealing with declarable substances was for each OEM to develop individual lists of substances. In some cases the list would be limited to substances existing in a material that was present in the vehicle at the point of sale. In others, the list would include process chemicals that were used in the vehicle manufacturing process, e.g., cutting fluids, degreasing agents, etc. Thus suppliers had to report against multiple lists. After discussions with their suppliers, the OEMs in the United States, Canada, and Europe sought to develop a simplified reporting process. Thus a stakeholder group was formed that consisted of the entire supply chain from plastic suppliers through the suppliers in all tiers and OEMs. This group is called the Global Automotive Stakeholders Group.

The GASG divides the globe into three regions — the Americas, Europe/Africa/Middle-East, and Asia/ Pacific — and is managed by an 18-member steering committee composed of representatives from each region. Each region has a technical committee that is charged with recommending additions to or deletions from the Global Automotive Declarable Substances List. The recommendations are based on a set of criteria (see sidebar) that are both reactive to regulations and proactive based on sound scientific evaluation. In other words, the system that has been developed could allow inclusion of substances prior to the development of a specific regulation.

Reporting is driven not only by the identity of a substance but also by a threshold — the quantity present in a material. While the current regulations are based primarily on the potential of a substance to be problematic, future decisions would more appropriately be based on risk assessment, where both exposure and potency are considered.

This globally harmonized list provides great value by reducing the resources required for reports and probably improving the accuracy of reports. The GADSL is now available on the Web.

Feature continues after sidebar

Global Automotive Declarable Substance List
The GADSL is a single, globally harmonized list of declarable substances with clear criteria and a transparent process to manage future versions. The GADSL file (available in PDF format) is the master document that lists individual declarable substances, substance groups (families) and describes how the GADSL should be used.

Criteria:*

The substance should be expected to be present in a material or part in a vehicle, and
The substance is regulated or is projected to be regulated by a governmental agency or authority, or
Scientifically valid methodology is used to assess if the substance offers a significant risk to human health and/or to the environment when present in a vehicle or a material or part in a vehicle
May include the substance if it causes a functional problem in vehicle design and is present above a level shown to be problematic by an international industry standard test
Reportable thresholds will be based on the lowest level required by regulation or reasonably required by scientific evaluation
*Adapted from www.gadsl.org

A formal system for declaring substances related to the information technology/electrical/electronics markets is also under discussion. The automotive experience serves as a reasonable template and is being evaluated. Original equipment manufacturers of electrical and electronic products and other stakeholders, including the chemical and plastics industries, also have begun to assess where standards can inform the overall system through work under the auspices of the International Electrotechnical Commission and recently through participation in ASTM Committee F40.

Testing for Substances of Concern

The need to test for substances of concern is not uniform over the automotive supply chain. The initial formulations of plastic compositions are developed by technically sophisticated personnel in the chemical/ plastics industry. The composition of starting materials is known based on existing methods of analysis, as is the identification of residual monomers after polymerization. This is typical for thermoplastic formulations. Thermoset formulations from polyurethane plastics to paints, adhesives to sealants are cured either during the part formation process or on the part. With these materials the chemical/plastics industry has no control over the final composition, therefore the company that forms some polyurethane parts (such as seat foam or headliner) or that applies the coating, adhesive or sealant would be the one to report the formulation information into IMDS. Generally companies purchase either the reactive monomers or a formulation and have control over the identity and amounts of raw materials used. So they should be able to accurately describe the cured formulation, with some technical support from their suppliers.

As described earlier, the issue of identifying substances of concern gains a new and challenging dimension once plastics are commingled and potentially contaminated with foreign substances (solid, liquid, and gaseous) at the product end-of-life recovery stage. At the recovery stage, developing a representative sample is nearly as challenging as developing a test method. The plastic components or shredded material may be composed of large pieces, chunks, flakes, and fines. Some components of shredder residue will adsorb more contaminants than others due to greater porosity. Testing for contaminants in shredder residues at this stage presents a significant challenge.

Generally speaking, greater resource recovery value can be derived by separating the shredder residue into mixed plastics and non-plastic fractions as a first step. A mixed plastics fraction might find utility as a feedstock into a variety of recovery operations — mechanical recycling, feedstock and chemical recycling, fuel recovery, and energy recovery — depending on market needs and the existing infrastructure.

Where technically feasible, the greatest value can be obtained from separating individual generic plastic types — for example, polypropylene, polyurethane, and polystyrene — from a mixed plastics stream. This requires the development of sophisticated separation technology. Once this is accomplished, depending on the origin of the initial plastics feedstock, the issue of contamination with heavy metals or organics of lower molecular weight may still need to be addressed. Again, standard analytical test methods may not be available in many cases. While there are Environmental Protection Agency methods for the determination of PCBs in soil samples, for example, no universally accepted standard method has been developed for measuring PCBs in or on plastics particles recovered from shredder residues produced during a metals recovery operation. Currently, existing methods are being adapted and studies show significant variation in results. This variation could have many sources, from interferences

by other organic compounds to inadequate sampling to work-up techniques. Automotive stakeholders involved in end-of-life vehicle recycling R&D are currently assessing the state of the art in this area.

Conclusions

The requirement to report substances of concern exists in several market segments and is being addressed globally by industry associations and stakeholder groups. OEM and supply chain cooperation within the automotive sector has been highly productive in identifying criteria and reporting methods for substances of concern. Similar efforts are under way in the electrical and electronic products sector. The development of effective technical standards responsive to market needs will require the establishment of an interface between the standards community and various market groups. The new ASTM Committee F40 on Declarable Substances in Materials is working to help establish this interface.

The automotive example discussed in this article presents one of the greatest challenges to methods development because of the complexity of the material mix and the number of contaminants that can be introduced in the stream. The initial manufacturing of a vehicle today largely uses virgin resin, and even though the analytical task is reasonably well understood, it can become complex and a significant cost consideration if not effectively defined. The degree of difficulty experienced in the analysis of plastics for declarable substances is magnified greatly when the plastics are not virgin resins but are recovered from end-of-life products. This is especially true in the case of automotive and appliance shredder residue but is true as well in the recovery of plastics from more defined streams such an end-of-life electronics. A further complication is that different types of end-of-life products exist within the consumer, business and industrial sectors.
Methods development, therefore, should focus on the issues at end-of-life where the greatest uncertainty exists. This is an area where the expertise being assembled in Committee F40 will be especially helpful. //

 
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