Waste Electrical and Electronic Equipment Directive Weee Ec

This legislation was passed on 13 February 2003 but did not come into force in the UK until 2 February 2007. This directive covers 'all equipment dependent on electrical currents or electromagnetic fields'. These are set into 10 categories and cover large household appliances, small household appliances, IT and telecommunication equipment, consumer equipment, lighting equipment, electronic and electrical tools, toys, leisure and sports, medical equipment devices such as dialysis machines,...

Suggested Further Reading

Denison, Annual Review of Energy and the Environment, 1996, 21, 191. 19. P. Schaefer In Proceedings of the SPI International Composites Expo '98, Nashville, TN, USA, 1998, Session 8-B, p.627. 20. J. Denault, C. Robert, J. Michaud and M.N. Bureau, In Proceedings of SPE Polymer Composites '99, Quebec, Canada, 1999, p.331. 21. R. Waite, Household Waste Recycling, Earthscan Publications, London, UK, 1995. 22. M.W. Meszaros, In Proceedings of Plastics Recycling Survival Tactics Thru the...

Development

For the development of new recycling technologies sufficient investment is required in both research and development (R& D) and new machinery and technology. Research needs to be targeted at the areas of greatest industrial need and, once developed, technologies need to be successfully transferred to industry. Best practice guidelines need to be available to highlight and disseminate the most up-to-date and effective treatment methods. 9.2 Design for Disassembly and Recycling Recycling...

Lossary

A material added to the polymer to increase its functionality or reduce costs. A process to increase the bulk density of the polymer. To be broken down into carbon dioxide and water by microorganisms. A material made up of biopolymer and other biodegradable additives. A naturally occuring polymer found in micro organisms, plants and animals. A process for production of hollow articles such as bottles. Naturally occurring biopolymer, found in plants. A process to create petrochemical feestock...

Reface

Although recycling has a very long history, it is only relatively recently that environmental protection and waste management issues have come to the forefront of both public and political awareness. The removal of plastics from both the waste streams and from landfill have since become areas of major interest. Outside the fields of expertise, generally little is known about either plastics or their recyclability. A number of specialist books are available, however none has addressed the need...

Useful Web Sites

The following sites also provide links to a number of other internet British Plastics Federation (BPF) www.bpf.co.uk American Plastics Council (APC) www.plasticsresource.com Accessed September 2007. RECOUP www.recoup.org Accessed September 2007. Waste and Resources Action Programme (WRAP) www.wrap.org.uk Accessed September 2007.

Updated for the Second Edition

Since the first edition was published in 2001, great strides have been made in increasing recycling rates worldwide. There has been expansion of infrastructure in the UK to support plastic recycling. Major achievements have been made in gaining widespread public support and participation for recycling schemes and specifically the need to manage waste on an individual household level. Council recycling of plastic bottles has become widespread* and the practice of providing free plastic carrier...

The Problem in Perspective Europe

Household Garbage Data Table

Plastic production accounts for about 4 of total oil consumption. Whilst this is not a vast percentage, it still represents a significant potential energy resource saving if plastics can be recovered. However, the main driver for plastics recycling is not energy recovery but landfill avoidance. The majority of plastics waste is produced by the packaging sector as shown in Table 10.1. It is therefore not surprising that packaging has been targeted as the prime area for material recovery. Table...

Additive Combinations for Specific Purposes

The additives used in a particular plastic will depend very much on the intended application. Outdoor applications for example, will require both light and heat stability. Bottle crates, made from a single plastic, high-density polyethylene (HDPE), have been extensively studied. The use of 100 recyclate without further stabilisation resulted in a loss of mechanical properties, cracking and colour fading after six months. However, when HALS and UV absorbers were incorporated, the recyclates...

Blow Moulding

Blow moulding is the third most commercially important process for plastics production after extrusion and injection moulding. It is used to produce a range of hollow articles, for example, bottles, fuel tanks and other large containers. There are two main variations, injection blow moulding and extrusion blow moulding. The process sequence for both is the same. The material is either extruded or injected to produce a tube like preform. The preform is blown out to the shape of the mould and...

Compression Moulding

Compression moulding is used to manufacture both thermoplastic and thermoset products. The process sequence is The moulding compound is loaded. The compression force and the heat of the mould cause flow. All the processes up to now have used materials in granular form, compression moulding however, often utilises raw materials in sheet form. Sections called blanks, of the correct weight, are preheated and then placed in the compression moulding tool. This is then closed to form the component....

Contaminants

The reasons for the use of single polymer rather than commingled waste for production of quality parts were discussed in Chapter 3. As polymers are immiscible and mixing can cause mechanical property deterioration, so can contaminants such as paint or dirt. Contaminants can include paint, labels, coatings, dust, wood, metals, glue residues or printing inks. Metals are a particular problem in reprocessing as they can damage the internal workings of the processing machines. Protection from metal...

Extrusion Blow Moulding

The material is fed through a transfer screw into a die head, where the material is melted and passes out through a die as a tube-like extrudate termed a parison. This is illustrated in Figure 6.12. This process can be either continuous or, with larger articles, intermittent. Figure 6.12 Extrusion blow moulding. Step 1 Parison formation Figure 6.12 Extrusion blow moulding. Step 1 Parison formation The parison extrudes down vertically and the process relies on the hot strength of the plastic to...

Hydrogenation

This is very similar to pyrolysis, but in this process the mixed plastic waste (MPW) is heated with hydrogen. As the molecules are cracked (the process is often termed hydrocracking), they are saturated with the hydrogen molecules to produce a saturated liquid and gaseous hydrocarbons. The synthetic crude oil produced is of a very high quality. It is necessary to keep the pressure of the hydrogen sufficient to suppress repolymerisation or the generation of undesirable by-products. In 1992, a...

Injection Moulding

Injection moulding is one of the most common manufacturing processes in use today. It lends itself to high volume production of both complex and precision parts with a variety of uses. It is a highly versatile process that is as successful and economic for both small and large components from an automotive bumper to intricate wristwatch parts. Figure 6.7 Injection moulding machine Figure 6.7 Injection moulding machine An injection moulding machine consists of an injection unit and a mould...

Introduction

Extrusion is a continuous process for the production of components such as pipes or sheets. It can also be used to produce compounds, which are mixtures of polymers or plastics and further additives. The most important features of an extrusion system are shown in Figure 6.1. These are Extruders can be of two types, i.e., single-screw or twin-screw machines. These two types of equipment perform slightly different tasks although the basic principles apply to both. This fits onto the end of an...

References

La Mantia, in 38 th IUPAC Proceedings of Microsymposium on Recycling of Polymers, Prague, Czechoslovakia, 1997, p.157. 2. ISO 4892-2, Plastics - Methods of Exposure to Laboratory Light Sources - Part 2 Xenon-Arc Lamps, 2006. 3. ISO 4892-3, Plastics-Methods of Exposure to Laboratory Light Sources - Part 3 Fluorescent UV lamps, 2006 4. ISO 4892-4, Plastics, Methods of Exposure to Laboratory Light Sources - Part 4 Open-Flame Carbon-Arc Lamps, 2006 5. ISO 877, Plastics - Methods of Exposure to...

The Formulation of Plastics

It was stated earlier in the chapter that plastics are mixtures of polymers and other materials. There are many additives commercially available that can be mixed with polymers. For example, glass or carbon fibre reinforcement gives them increased strength. Flame-retardants can be added for flame resistance. Plastics can be coloured with pigments for aesthetic or technical purposes, or they can be made more heat and light resistant by the use of stabiliser additives. These are just a few...

Thermoplastics

These materials melt and flow when heated and solidify as they cool. On subsequent reheating they melt and regain the ability to flow. This means they can be reprocessed and hence recycled Table 2.3 Common thermoplastics and their applications Packaging, pipes, tanks, bottles, crates Caps, yoghurt pots, suitcases, tubes, buckets, rugs, battery casings, ropes Packaging 2 years Battery casings 10 years Mass produced transparent articles, yoghurt pots, fast food foamed packaging, cassettes...

Thermosets

Thermoset materials are melt processed, often in a similar manner to thermoplastics. However, once formed and cooled they cannot be reprocessed, they decompose before they can melt. Therefore, they cannot be reprocessed in the same way as thermoplastics. This is because they are chemically crosslinked by a process termed 'curing'. The result is a highly dense molecular network making the material stiff and brittle. The differences in the arrangement of molecules between thermoplastics and...

Wwwpolymerbookscom

Orders or queries may also be directed to our publication sales team E-mail publications rapra.net Tel +44 (0) 1939 250383 Fax +44 (0) 1939 251118 Published by Smithers Rapra, 2007 ISBN 978-1-84735-078-7 Introduction to Plastics Recycling provides information on plastic materials and technology in relation to the options for, and problems associated with, recovering and recycling plastics. This new edition discusses the increase in recycling rates worldwide in recent years. It considers the...

Waste During the Injection Moulding Process

Lamellenwand Ablage

As well as reject injection mouldings, waste is also generated through runners or sprue as shown in Figure 6.8. These are produced on each moulding and are the channels used to feed molten plastic from the injection unit into the mould. These, as well as reject mouldings, can be fed back into the machine if care is taken to avoid contamination. For this, slow-running, largely dust-free granulators are available, which can be quickly and easily cleaned as required. Injection moulding is complex...

Injection Blow Moulding

Injection and extrusion blow moulding take their names from the methods used to produce the tube for blowing. In extrusion blow moulding the tube is called the parison, in the case of injection blow moulding it is termed a preform. Thus in injection blow moulding, injection moulding is used to produce the preform. The process sequence for injection blow moulding is as follows The preform is injection moulded. It is transferred to a blowing station and inflated inside a mould. It is transferred...

CoInjection Moulding

There are a number of variations of the injection moulding process, one that is particularly applicable to recyclates is co-injection moulding. Co-injection moulding produces a sandwich like structure that can be used to encapsulate recyclate materials, covering them in a layer of virgin skin material. Figure 6.9 Co-injection moulding machine Figure 6.9 Co-injection moulding machine Figure 6.10 Skin core configuration of co-injection moulding A co-injection moulding machine has two injection...

Creation of a Recycling and Recovery Infrastructure for Plastics

This chapter steps away from the technology of plastics recycling to look at the bigger issues facing the plastic recycling industry. Chapter 1 highlighted the issue that for plastics recycling to be sustainable long term, a balance must be reached between the technology, economics and the environmental issues. The plastics recycling industry must be self-supporting. In order for this situation to be reached a number of criteria must be met 1. The development of cost effective sorting and...

Acknowledgements

I would like to acknowledge the following for their support during the writing of this manuscript My dad for knowing nothing about plastics and thereby being a willing guinea pig. His good humour, comments and bafflement at anything to do with chemistry were invaluable. Special thanks to Debbie the Bear, Deb and Jake. All photographs were expertly taken by Graham Canham, unless otherwise stated. Thanks to Sally for giving me the opportunity to publish this book originally and to Fran for...

Single Screw Extruders

As the name suggests, the single-screw extruder has a single Archimedian screw that rotates in a heated metal barrel. Unlike twin-screw machines, which require material to be dosed into the screw to prevent an overload, solid material enters the barrel through a gravity feed hopper at the feed throat. This material is conveyed along the extruder barrel by the action of the screw. The material is plasticated during this action and then passes through a breaker plate before exiting at the die. A...

Sinter Moulding

The sinter moulding process can be used with a broad variety of mixed plastics. The process is tolerant to contamination from materials such as aluminium and paper, and panels made with waste wood chips have been manufactured 3 . The formulation can also be varied to produce mouldings with a range of properties for use as panels, sound proofing or packaging materials. In this process plastic flake is plastified in a heated mould and subjected to pressure. The material passes through a metal...

Reprocessing of Thermoplastic Recyclates

Mechanical recycling is the most common method of recycling. Here plastics are physically ground back to a suitable size (regrind) and reprocessed. The end use can be the original one or something different. In the plastics industry it has long been common practice to reprocess waste material arising from normal production. This in-house recycling, known as primary recycling, makes economic sense as it reduces both production waste and utilisation of raw materials. For example, with injection...

What Are Recyclates Used

With the exception of food contact and medical products for which many recyclate materials are unacceptable, recyclates can be used in a variety of ways. Refuse sacks are an especially good outlet for recyclate materials. These products, consisting mainly of LDPE, may be made entirely of recyclate materials. Products like this are rare and the majority of recyclate containing products are blended with virgin materials. Supermarket carrier bags also often have a percentage of recyclate materials...

N

Packaging 131, 133 Parison 79 Phase 29 Physical changes during processing 31 Physical recycling see mechanical recycling lumber 95 Plastication 66 Plasticisers 21 Polyamide 17 Polycondensation 12 Polyester 15 Polyethylene 12 Polyethylene terephthalate 112 Polygonic acid 145 Polylactic acid 145 Polymer 11 Polymerisation 12 Polymethyl methacrylate 114 Polyolefin 17 Polypropylene 17 Polystyrene 14 Polyurethane 19 Polyvinyl chloride 14 Preform 84 Primary recycling 45 Prime grade 13 Process...

Heat

A thermoplastic cannot flow in its solid state. To enable it to flow it needs to be heated above its melting point Tm . Some melting points of common plastics are shown in Table 3.1. Just from these examples, a wide range of melting points can be clearly seen. Once a polymer is heated above the melting point the viscosity will decrease as the temperature increases. The rate of this change varies, according to the particular type of material. Eventually the polymers will reach a point where they...

Why Plastics Need to be Sorted

We have already seen that thermosets cannot be reprocessed in the same manner as thermoplastics, because they do not re-melt. Therefore separation is needed of thermosets and thermoplastics. But what about thermoplastics do they need to be separated from each other Can we simply just mix all the plastics together and reprocess them Well, if we could do this, plastics recycling would certainly be much easier. In some cases it may be possible to simply mix and reprocess but generally the...

Degradable Plastics

Since plastics can comprise up to 40 bulk of all the waste in landfill, another waste management strategy is to speed up their chemical breakdown once they enter the waste stream 5 . This is not recycling, simply an attempt to limit environmental damage. Plastic litter that is dropped will thereby harmlessly degrade in the natural environment. It makes good sense. In this chapter it has been shown that stabilisers can protect plastics from environmental damage. However, one solution to the...

Other Methods of Recycling and Waste Disposal Options

In Chapter 1, chemical recycling and energy recovery were introduced as alternatives to mechanical recycling. We have seen how plastics can be reprocessed if they are pure streams, if they can be sorted, or if suitable blends can be obtained. We have also seen potential applications for mixed plastics where the quality of the final product is reduced, but the inherent properties of all plastics such as rot-resistance can be utilised. An example of this is in wood replacement applications....

Transfer Moulding

This process combines elements of injection moulding and compression moulding. It is similar to injection moulding in that a fixed weight of material is transferred into a mould. Transfer moulding was originally developed from compression moulding, to allow production of more complex parts incorporating holes, recesses or inserts 2 . The result was a process whereby the mould was closed first and the moulding material then transferred by a compressive action into the cavity. A number of...

Energy Recovery

Energy recovery can be defined as incineration to recover inherent energy. Given that polymers are made from oil, it is not surprising that they are quite good fuel sources when they are burnt. The amount of energy that can be recovered depends on the calorific value of the material. Literature values tend to give an average calorific value of mixed plastic waste as 35 MJ kg. When compared to paper 16 MJ kg and organic waste 3 MJ kg , it can be seen that plastics give a relatively high energy...

Rheology

Rheology is the study of deformation and flow. Consider the following examples of flow 1. Squeezing toothpaste through a tube, 2. Tipping honey from a spoon, and The toothpaste, honey and water all have different viscosities. The toothpaste is the most viscous, the water the least. Viscosity means the resistance to flow. In viscous flow, a material continues to deform as long as a stress is applied. To put it more simply, in the case of the toothpaste tube, the toothpaste is squeezed out only...

Case Study Packaging

Recycling rates vary greatly across Europe, due to different legislative and environmental measures adopted by member states. The country at the forefront of implementing plastics recycling schemes is Germany. Packaging waste concepts introduced in Germany in June 1991 have provided much valuable data for the rest of the EU. The target set was 64 to be recycled by July 1995, based on a system of collection, sorting and recycling technology. The high environmental awareness present in the German...

Short Term Mechanical Testing

Eps Figured Moulding

Experiments for measuring the effects of reprocessing have now been discussed. MFI as a method of monitoring degradation has already been mentioned, next the methods of mechanical evaluation will be considered namely tensile and impact properties. Tensile testing can be thought of as a stretching test. Tensile properties are a method used widely to analyse the short-term stress-strain response of a material. Computer controlled tensile test machines are commonly employed, allowing one simple...

Case Study Plastic Lumber

Recycled plastic is finding use as a wood replacement product. It does not splinter, rot or warp like conventional wood. It does not require preservation treatments and its lifetime can exceed over 50 years. There are now a number of plastic lumber type products available ranging from those made of entirely of one material, generally HDPE, to mixtures of plastic, wood, rubber and other materials. A number of factors are pushing the use of plastic lumber, especially in the USA where alternatives...

Polymers

Polymers take their name from two Greek words poli which means many and meros which means parts. This is because they are made up of a number of repeat units, called monomers. The simplest and most commonly used monomer is ethylene. Chemically it consists of two carbon atoms C and four hydrogen atoms H . It can be represented in the two ways shown in Figure 2.1. The lines shown in Figure 2.1 a represent the bonds that exist between the atoms to form a molecule. b CH2CH2 Figure 2.1 An ethylene...

Agglomeration

Agglomeration is a process stage to be carried out after the material is sorted into a fairly homogeneous stream. The aim of the agglomeration is to increase the bulk density of the waste, which is necessary to ensure good feeding for some plastication units. It finds most application in waste plastics with film flake, which can have a bulk density of just 100 to 150 kg m3. This can make both feeding and storage cumbersome. Examples of film waste before and after agglomeration are shown in...

Intrusion Moulding

The intrusion process is suited to mixed plastics. Generally, they are finely ground before processing to aid dispersion. The process has elements of extrusion in that a plasticating unit is used to soften the mixture, which is then fed into a mould and this is then cooled. On rotating systems a number of tools can be filled as others are cooled usually by submerging them in water . Once the plastic has cooled it can be ejected or removed depending on the type of mould that is used. The process...

Rise of the Biopolymers Recycling versus Degradation

Cellulose Structure

In Chapter 7, the conflict between recycling plastics and causing them to degrade in the environment was briefly discussed in the context of oil based plastics. This chapter is devoted to another naturally biodegradable set of materials called biopolymers. The polymers discussed up until now have all been made synthetically, however, polymers also occur naturally and are produced by microorganisms, plants and animals. Polymers that are produced by living organisms are called biopolymers. The...

Conclusion

An overview of the processes discussed in this chapter is given in Table 6.1. Whilst primary mechanical recycling will continue to be common practice amongst plastics processors, secondary recycling is subject to both practical and economic limits for use. Success depends primarily upon the economics of sorting to obtain single polymer materials, and knowledge of material provenance and degradation history. Processes adapted from conventional machinery to take more highly contaminated feedstock...

Weld Lines

Plastic Film Blowing Machine Diagram

Whenever molten flows come together a weld line will be produced. Weld lines are common to almost all processing operations as often on passing through extruders or moulds extruder dies, injection moulding tools, blow moulding tools , molten flows will meet obstructions which split material into different streams, this is shown in Figure 6.15. How well the materials can 'knit' back together, will affect the weld line strength. Figure 6.15 Molten material flowing around obstruction Figure 6.15...

Chemical Recycling

One other method is chemical recycling, where the polymer is broken down into smaller molecules that can be easily separated from impurities. In chemical recycling, also known as feedstock recycling, plastics are used to make raw materials for petrochemical processes. Common examples of such processes are cracking and hydrogenation. Processes like these place restrictions on the types of materials they can handle and each method has slightly different restrictions and tolerances. Generally,...

Twin Screw Extruders

A twin-screw extruder can have either counter-rotating or co-rotating screws. Co-rotating twin-screw extruders are used mainly for compounding. Counter-rotating screws are generally used in the processing of heat sensitive materials, such as polyvinylchloride PVC pipes and sheets. They are especially suited to heat sensitive materials, because they allow greater temperature control. The aim of both types of screw is plastication, that is, to produce an easily formable melt stream. The...

The Case of Thermosets

In Chapter 2 the reasons that thermosets could not be reprocessed in the same way as thermoplastics were introduced. Thermosets are crosslinked, meaning they cannot be re-melted and reprocessed in the same way as thermoplastics. Until relatively recently thermosets were considered non-recyclable but with recyclability becoming an ever increasing criteria for material selection, the thermoset business faced a serious threat if ways could not be found to overcome this hindrance to market...

Assessing Property Deterioration Caused by Repeated Cycling by Injection Moulding

Closed Loop Cycling

Simple experiments can be performed to assess the effects of processing on properties. Mouldings should be produced using the same conditions as used for full production to get useful and representative results. The following three experimental procedures explore the recycling limitations of a plastic material. They identify the limits of reprocessing, as regards retention of mechanical and rheological properties, and allow the limits of recyclability to be assessed in terms of comparisons of...

Recycling Techniques

Waste Recycling Techinques

Despite increasing research efforts it is not yet economical to separate the wide variety of plastics that end up in the waste stream. The ideal is streams of single, clean and homogeneous recyclates, which present little technical effort for recycling. Of course, streams of this type, mainly industrial, can and are recycled. However, mixed waste streams present more of a technical and economic challenge to recover. Consider your household rubbish, perhaps even rummage in your bin What plastics...