Lightweight Platic Panels Manufactured from Recycled Plastics – Panels for Commercial vehicles and Other Applications

Topics Covered

Background

The Panelplus Project

Sources of Plastics for Recycling

Methods for Converting Plastic Waste into Lightweight Polymers

Producing Sandwich Panels

Panel Weights

Versatility of the Panels

Benefits of Lightweight Panels for Commercial Vehicles

Environmental Benefits of the Lightweight Panels

Targeting the Commercial Vehicle Sector

Production and Testing of the Panels

Other Applications

Pallets, Crates and Boxes

Temporary Flooring and Storage Boxes

Environmental Benefits

Energy Savings

Feedstock Quality

Recyclability of the Lightweight Panels

Summary

Background

Bottled drinks and ready meals could soon be delivered using trucks made from their recycled packaging thanks to a two year project funded by the Waste and Resources Action Programme (WRAP) that has now reached trial stage.

The Panelplus Project

The Panelplus project was set up to investigate the viability of using domestic and industrial plastic waste to form high-performance structural composite panels on a commercial scale. The resulting material has been shown to offer a host of cost, weight and environmental advantages to commercial vehicles.

The body panel was developed by a consortium led by Euro-Projects Ltd (EPL), a leader in the application of thermoplastic composites. EPL received backing under WRAP's R&D funding programme, set up to encourage the development of new, commercially viable recycling techniques, product applications and end markets for recycled materials and products. Awarded almost £500,000 by WRAP, funding was matched by a consortium including EPL, Safecomp Ltd, Plastic Reclamation Ltd and Loughborough University.

Sources of Plastics for Recycling

The recycled feedstock comes from a number of sources. Polypropylene (PP) is sourced from various packaging derived materials, such as bottle caps, polyethylene terephthalate (PET) comes from carbonated drinks bottles, and polyethylene (PE) is found in film grade LDPE.

Methods for Converting Plastic Waste into Lightweight Polymers

Three methods of converting the plastic waste into lightweight polymers were investigated, and of these, two (nitrogen foam expansion and honeycomb film) were proven to be effective in the manufacture of low density (40-70kg/m3) cores on an industrial scale. Four types of fibre reinforced thermoplastic composite skin - PP and PET resins, and glass and carbon fibres showed potential as skin materials for panel production.

Producing Sandwich Panels

EPL, then used industrial scale machinery to manufacture the lightweight sandwich panels, using recycled PE foams with recycled PET and PP honeycomb cores, and attaching both PET and PP-based composite skins using thermofusing techniques.

Panel Weights

The core layers vary in weight according to their desired properties, but the panels have an overall recycled content of approximately 52%. This means that for a 1m2 panel, the outer skin layers weigh around 2.1kg and the core about 2.6kg for a core density of 80kg/m3. Translating this to a standard 7.5 tonne van, the total amount of core material used would be equivalent to 2,500 two litre carbonated drinks bottles.

Versatility of the Panels

The new plastic panel design is versatile due to the fact that it is much lighter than many conventional structural panel materials. Although thicker panels are needed to compete in stiffness terms with alternatives such as plywood, the weight savings unlock a wide range of applications.

Benefits of Lightweight Panels for Commercial Vehicles

The potential benefits for commercial vehicles are significant. When used in the manufacture of truck bodies, Panelplus panels weigh 60% less than the equivalent GRP plywood panels, allowing up to 450kg of extra payload on a 7.5 tonne truck and 240kg on a 3.5 tonne van, saving one out of every eight to 10 journeys.

Environmental Benefits of the Lightweight Panels

For the transport sector, this extra payload capacity could deliver very real fuel savings in the order of £8 million per year, with a reduction in CO2 emissions of around 26,800 tonnes. Even in cases where the additional payload capacity is not taken up, the weight saving alone would save 1.44 million litres of fuel a year. And the benefits do not stop here. Panelplus is impervious to water, does not rot or biodegrade, and can be repaired more efficiently and quickly than other panel materials.

Targeting the Commercial Vehicle Sector

It is these benefits that led to the targeting of the commercial vehicle sector as a key potential market at the outset of the project. The automotive industry is one of EPL’s target sectors, and the project consortium was drawn up to ensure the necessary expertise was available right through from the initial reprocessing of the plastic waste to commercial scale manufacture, use and marketing of the product.

Production and Testing of the Panels

Omnia Composite Solutions, in partnership with Safecomp Ltd, have provided expertise on the commercial vehicle sector, leading van and truck body fabricators Alloy Bodies Ltd fabricated the panels for the test vehicles, and the Institute of Polymer Technology and Materials Engineering at Loughborough University carried out a comprehensive testing regime. Leicester City Council helped to initiate the project. Working together, the consortium has been able to move from concept through to a market ready product that has attracted considerable commercial interest.

Other Applications

Discussions are now taking place with companies in the transport, construction, packaging and marine industries, indicating that it is not just the transport sector that offers market potential for the new panel design. EPL, has created a panel design database based upon a number of properties determined experimentally, which can be used to estimate the effects of changing design variables such as panel geometry, core material and skin material. The research has shown that different core and panel structures provide different insulation, acoustic and impact resistance properties, opening up opportunities in a number of sectors, including caravans and portable cabins, staging and decking, and flooring.

Pallets, Crates and Boxes

Because the panels are thermoplastic, it is also feasible to automatically edge close, bend, fold and join them together using efficient hot gas or electrofusion welding techniques. This makes it possible to produce added-value structures, such as pallets, crates, boxes, directly from flat thermoplastic composite panels more efficiently.

Temporary Flooring and Storage Boxes

Panelplus has already been tested in a number of other applications, including temporary flooring and storage boxes, where strength and impact performance are important factors, and where the weight saving offers additional benefits in terms of manual lifting and handling. These trials have proved encouraging, and in total over 40 million m2 of potential applications for Panelplus have been identified.

Environmental Benefits

The outlook is not just favourable in commercial terms, but also from an environmental perspective. Environmental impact assessment work has shown that mechanical recycling of one tonne of PE saves 1.8 tonnes of oil, with a subsequent 60% cut in SO2 emissions, 50% cut in NOx and a reduction in CO2 of over 70% (equivalent to 5,500 kg). Primary recycling of the plastics saves 26.16MJ/kg, and taking into account the retained polymer, 66MJ/kg of energy is conserved.

Energy Savings

The total secondary energy to create a thermoplastic sandwich panel from recycled plastic waste is 31.19 MJ/m2 for a 30mm thick panel, comparing extremely favourably with the energy requirement of 102 MJ/m2 to form 17mm thick plywood panel.

Feedstock Quality

The application also favours recycling from the point of view of feedstock quality. In many applications for recycled plastics, consistency and colour are critical. But the requirements for Panelplus are less restrictive. Since the virgin material outer skins present a good appearance, as well as being strong, stiff and impact resistant, the inner recycled plastic core needs only provide the required mechanical (shear/compression), acoustic and insulatory properties.

Recyclability of the Lightweight Panels

Closing the loop, there is yet another benefit in that panels based upon recycled polyolefin cores have been shown to be potentially recyclable themselves. The recycled panel feedstock can be considered to be a value-added material, in view of the relatively high glass fibre concentrations, which deliver additional performance benefits.

Summary

Trucks made from Panelplus are currently being trialled by Northgate plc, a leading UK fleet hire company, and interest from the launch of Panelplus at the Commercial Vehicles Show earlier this year has translated into orders for over 300 truck bodies to date. The consortium is currently investigating the option of setting up large scale commercial production in the UK, as well as addressing opportunities for future applications.

 

Source: Materials World, Vol. 12, No. 6, pp. 25-27, 2004.

 

For more information on this source please visit The Institute of Materials, Minerals and Mining.

 

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