The winner of first prize for the best product was Mehrwerk Designlabor for a novel lightweight shelving system. Werzalit came second with injection moulded square decking elements for extruded decking, and Wacker Polymer Systems was third with its flexible WPC for indoor applications. This involved using a PVAC ethylene copolymer binder to optimise the wood-like appearance. Wacker Polymer Systems has also made progress in the area of coatings and veneers.

Pritchard said that although additives were expensive and initial purchase costs of WPC were already fairly high, certain additives were necessary to achieve good durability and they could extend product lifetimes to make real whole-life costs of buying WPC products competitive. Lubricants could also improve production economics.

It has long been suspected that WPC might show slight degradation in extreme climates. A leading manufacturer of the biocide zinc borate has now reported that micro-organisms can grow on the surface of WPC even in temperate climates provided that the moisture content reaches 25%. It had previously been thought that such high moisture levels were never reached in WPC, but apparently the outer surface layer can sometimes exceed this level. Normally moisture uptake tests measure the average moisture absorption, which is always much lower than the surface value and which seems reassuring. Moreover, other reports by different investigators indicate that even in extremely hot dry climates (as opposed to the more obvious hot wet case) the long term performance of WPC must be re-evaluated because microcracking can sometimes occur, creating an entry path for micro-organisms. These then seriously deplete the wood.

However this is not meant to suggest that WPC is as vulnerable as wood. WPC remains a far more durable material than softwood for use outdoors wherever low maintenance costs and long lifetimes are valued and high strength is not a priority. In temperate climates, particularly when temperatures remain moderate throughout the year, WPC should present no real weathering problems.

Most European countries are not as hot as the places where these degradation processes were detected, but there are a few spots where caution should be exercised. It is understood that zinc borate has not been submitted for approval for use in WPC in the European Union whereas it has in the USA. Other methods of guarding against weathering are available, not all of them involving a biocide, and many of them have already been researched at the laboratory level. Cost issues are likely to determine which type of protection is the more widely adopted commercially. The problems will arise, if at all, where WPC is used in very hot climates. It should be remembered that competitive materials (timber and concrete, for instance) also suffer degradation problems of various sorts.

Chris Foster, of Hackwell Group and environmental consultancy EuGeos, presented a paper on the evaluation of the environmental performance of WPC at the "Symposium International sur les Composites Bois Polymères" (March 2007, Bordeaux, France).
This conference brought together over 150 attendees from the business and academic communities. There was clear evidence from the presentations and associated exhibition of further advances in the technical and aesthetic performances of WPC. On the standardisation front, the work of the Technical Committee establisehd within CEN is beginning to bear fruit.
Chris Foster's presentation stressed the importance of quantifying environmental performance using life cycle assessment in the ever-more environmentally-conscious construction product market.

The great majority of WPC is made from just three thermoplastic resins— polypropylene, polyethylene and PVC. This is because the WPC has to be processed below the temperature at which wood darkens and degrades, namely 200ºC. This has made the task of using high-melting resins like nylon very tricky. If it could be done, the mechanical properties of WPC would probably be improved.

Fortunately there are several different types of nylon, distinguished by numbers, such as nylon 6 and nylon 11. The higher the number, the lower the melting point. The readily available nylon 6 melts at 215ºC but higher-numbered nylons could work. Researchers at Oregon State University in the US have tried nylon 12, which melts at 175ºC. (The grade they used was Grilamid L20G from EMS-Chemie North America). The MOR (modulus of rigidity) of the resulting WPC rose with increasing wood content to reach about 80 MPa at 60 wt % wood.

They also made similar WPC with HDPE and PP. The MOR values for these were only about 20 MPa for HDPE and less than 30 for PP. So the benefit of using nylon was very great. Tensile strength showed a similar pattern, with 40 MPa at 60 wt% wood, again about four times the value for HDPE. The advantages for modulus of elasticity were not so great.

The moisture absorption of the resulting WPC was not the main focus of attention, but nylons tend to absorb more readily than polyethylene. Some industry sources have suggested that it would be attractive to use post-consumer nylons from old carpets.

The 8,000 tonnes capacity, utilising four extruders already represents a doubling of capacity during 2006, with the planned 2007 expansion to 8 extruders confirming Beologic's position as Europe's largest producer of WPC compounds.

Beologic claimed that it is ultimately aiming for a capacity of 40,000 tonnes per year of WPC compound.

20-30% of Beologic's current output is supplied to injection moulders with the bulk (70-80%) being supplied for extrusion applications. The largest of these is decking as well as flooring and cladding. However, completely new niche applications have also been found for Beologic's WPC compounds including poles in Venice canals with enhanced resistance to sea water exposure and replacement of aluminium poles used in the Belgian telecommunications industry for temporary traffic lights to combat the stealing of the metal poles for their scrap value.

Work is also continuing on a number of new product developments including foamed WPC to reduce the relatively high WPC density, WPC products using polystyrene and polylactic acid (PLA) polymers and the incorporation of biocides. It has been claimed by Rio Tinto Minerals (USA) that there is clear evidence based on field exposure that the surface regions of WPC products can easily absorb the necessary 25% of moisture to harbour fungal species. Other areas of development at Beologic include improving flame retardancy of WPC so that it is closer to that of conventional PVC and even incorporation of perfume to provide a typical wood fragrance.

Predictions for the US Fencing Market

On November 1 2006 Geoff Pritchard of Hackwell Group made a presentation about the latest commercial applications and technical properties of wood plastics composites to the Telford Polymer Association at the Association's monthly meeting, which was held at the UK headquarters of Rapra Technology. Prof Pritchard identified lack of strength and stiffness and high thermal expansion as properties needing improvement, while low moisture absorption and workability were recognised as important advantages.

A summary of this presentation can be downloaded from the Telford Association's website.The Association's presence in Telford is a reflection of the concentration of a number of polymer-based companies in the area (Shropshire). Some of the Association's members work for Rapra, part of the US-based Smithers group of companies, which carries out both laboratory consultancy and information provision relating to the plastics and rubber industries.

A company that produces mouldable wood, Technaro GmbH, is developing injection-moulded musical instruments. It is starting with harmonicas, flutes and accordions. Technaro GmbH, originally set up by the German Fraunhofer Institute, was spun off about eight years ago. Technaro's material is called Arboform, and major environmental advantages are claimed for it. It is essentially lignin mixed with natural fibres to produce a wood-like composite. Such compositions do not necessarily contain a petroleum-based thermoplastic resin binder and are rather different from "conventional" wood plastic composites.

Other research to find a substitute for wood in musical instrument is being supported by the German government. These activities take place in a region with an exceptionally-high concentration of musical instrument manufacturers and involve several companies and research institutes. One of the project participants, Adler-Heinrich, a musical instrument manufacturer, is producing flutes from "liquid wood". The moulded liquid wood is water-resistant and can be washed hygienically. Another musical instrument company, Harmona, is working on accordions, where injection-moulding of small parts would enable more cost-effective production than the traditional manual method.

The US-based speciality chemicals company Chemtura (supplier of mainly plastics additives) was formed just over a year ago by a merger of Crompton and Great Lakes. Chemtura has now announced the sale of its majority holding in Davis Standard, the extruder company that makes the Woodtruder extrusion equipment used for extruding wood plastics composite. The purchaser is the private equity firm Hamilton Robinson, which already held a minority share.

Davis Standard had once been part of the Crompton empire. It has its HQ in Pawcatuck, CT, USA, and owns German and UK subsidiaries, including D-S Brookes, which makes extruder screws and barrels.

It is claimed that the Woodtruder can process fibers from sawdust, wood (both hard- and softwoods), flax, sisal, rice husks, coffee and peanut shells, recycled car tyres, and other similar materials.

At the AdCon plastics additives conference (October 17-8, 2006) organised by Rapra Technology Ltd in Cologne, Germany, Bruno Jacques of C-Tech Europe described his company’s non-toxic additives, designed to protect plastic products from being nibbled by rats, termites and other pests. Since WPC is often proposed for infrastructure applications where pests are a significant factor, it seems these additives could be of some interest to the WPC market. Possible applications include cable duct lids, fencing, waterfront and railway products. Jacques suggested that the idea of using non-toxic additives derived from predators’ urine was originally developed because of Hindu considerations for the sanctity of animal life (C-Tech’s headquarters is in India). However, American WPC with typically 50% resin is claimed to be resistant to termites, and it is too early to say whether European formulations with their higher wood contents still have enough resin in them to deter rats.

The formation of films on WPC decking has often been observed, and it is usually recommended that the owner carry out regular cleaning operations. At the meeting mentioned above, Svoboda Tabakova of the Institute of Molecular Biology in Sofia, Bulgaria described how to suppress undesirable biofilm formation on plastic surfaces such as pipes, door knobs and handles etc by using appropriate additives. The two additives investigated (tetramethyl dithiooxamide and paraphenylene diamine) both showed good biofilm growth inhibiting ability.
Note: This website does not undertake to claim that these additives will necessarily be effective in any specific circumstances. It is recommended that anyone interested in evaluating these compounds should first contact the Hackwell Group, who will put them in touch with the author of the paper.

WPC is intended to compete with wood, UPVC and MDF but competition from recycled plastics also needs to be taken into account. At the recent Recycling and Waste Management Exhibition in Birmingham, England (September 2006) there was a wide range of product-specific waste bins on display, designed to encourage people to sort the articles they want to throw away, making recycling easier and cheaper. Companies were also offering recycled plastics for use in the same type of applications that WPC is usually recommended for.

Now Milestone Design of Yorkshire, UK has started offering kitchen fitments that use solid board made from recycled plastic. The worktops are made from recycled vending-machine coffee cups and the cupboard doors from recycled yoghurt pots. However, Milestone acknowledges that conventional woodworking tools cannot be used with some plastics, whereas WPC can be easily worked. It can be difficult to control the colour of recycled plastics too, if the original articles were dark. However, Milestone has found considerable interest from universities concerned with providing kitchens for student accommodation units.

JER Envirotech (Vancouver, British Columbia), one of Canada’s leading manufacturers of wood plastic composites, has announced that its new factory near Kuala Lumpur, Malaysia is now able to produce panels from thermoplastic resin and locally-available rice husks .(The WPC industry has made it easier to employ rice husks for making durable goods).

Ernie Calica, general manager and vice-president of its Asian division, claims that JER Envirotech was the first company to produce large area (4 feet by 8 feet, or 1219 by 2438 mm) WPC boards on a commercial basis.

This new production facility in Malaysia is a joint-venture, with JER Envirotech having the majority shareholding and Asia Pacific Microspheres the remainder.

JER Envirotech claims to be aiming to achieve a truly global WPC operation and is currently also engaged in setting up facilities in both India and the Philippines in addition to those in Canada and Malaysia.

The German company Beta Gamma Service (BGS) is developing and promoting the use of gamma irradiation to improve wood plastics composites. Unlike many processes which involve treatment of the raw materials, it is applied to the fabricated products after they have been moulded or extruded. Properties improved are said to include the modulus, hardness, and water resistance.

The effects of gamma irradiation treatment on unfilled resins have been fairly extensively researched for various reasons, and its application to WPC was proposed in the scientific literature a few years ago as a possible alternative to the use of compatibilisers, as mentioned in the 2003 Hackwell Report on wood plastics composites.

Most of the wood flour used in polymers is currently used in polyolefins and PVC, and very little has been done to develop wood as a filler for elastomers. Recently, though, researchers at Sofia University (Bulgaria) have investigated the use of wood as a filler in rubbers, and have found it to be compatible with a wide range of synthetic elastomers such as SBR, butadiene-acrylonitrile and polyisoprene. They have now examined the effect of wood on the cure rate of natural rubber.

Ordinary wood flour does not seem to have an adverse effect on the cure time of natural rubber. In some experiments they pre-treated the wood with ammonia or a corona discharge. Wood appears to improve the stiffness of the rubber, but not the strength.

UPM of Finland claims to be the world's biggest producer of paper, and therefore it is well placed to deal in other cellulosic materials, including wood plastics composites. Finland is short of WPC producers at present, although there has been some interest with the setting up of a WPC Development Centre by Conenor.

UPM has now decided to enter the market and it has already bought the 100th Fiberex extruder to be sold by machinery market leader Cincinnati for use in WPC extrusion. The Fiberex design is believed to be the one most favoured by European WPC producers over the past few years.

The outdoor durability of WPC has been widely praised, but long term testing reports are still scarce. One specific threat to durability is temperature changes. In the past, outdoor winter conditions such as freeze-thaw cycles were thought not to damage wood plastics composites. (A freeze thaw cycle is usually considered as consisting of water uptake followed by the freezing and thawing of the absorbed water).

Michigan University workers Jeannette M Pilarski and Laurent M Matuana subjected both PVC-based and polyolefin-based WPC to a lab test consisting of a modification of ASTM D 6662-01. Each freeze-thaw cycle consisted of a water soak to equilibrium at 21 ºC, followed by freezing for 24 hours, then thawing for 24 hours.

Fifteen cycles (said by the authors to be an extreme condition) produced a fall of 49% in the modulus of elasticity (MOE) and 21% in the modulus of rupture (MOR) of maple wood polyolefin composites. The pine wood equivalents lost 5% MOR and 37% MOE. The cycles increased the number of pores and their size, although the density of the WPC either stayed the same or slightly increased. The interfacial bonding decreased.

PVC materials showed rather similar trends. The researchers believe their results are relevant to the construction uses of WPC.

Hackwell Group analysts point out in their latest Report that substantial falls in the mechanical properties of WPC have been reported after water uptake alone, without freezing. It is important to note that the residual strength of the wet WPC still compares well with that of competing wood substitutes, some of which have a much greater tendency to absorb water than WPC. The reversibility on drying of the property changes also has to be further investigated.

INEOS will now begin the process of fully integrating Innovene into its organisation. The review of Innovene’s operations, products and markets, which began in October, quickly confirmed the complementary fit of the two companies, but the detailed design of the ongoing structure continues. Innovene will assume the INEOS name and be focused into product-line business entities, along similar lines to INEOS’s existing organisational model.

Ethylene prices have been further aggravated by capacity problems resulting from outages, not all of them from the autumn hurricanes. Dan Demers of A-top Polymers, Windham, NH, USA, says that American polyethylene producers have been operating flat out, just to deal with average demand levels.

The selling price of WPC is high compared with softwood. If resin prices continue to rise over the next two or three years with increasing demand from China and India, there will be an incentive for WPC suppliers to push up wood: resin ratios in WPC to restrain material costs. The price of additives also depends on oil. But wood:resin ratios are already higher in Europe than the US, and there can be a fall-off in moisture resistance at very high wood levels. Another step would be for European producers to use more recycled resin (rather more than half the big US producers of WPC use recycled resin, but the proportion is much lower in Europe). Demers points out that "off-spec" resin is another alternative if you know where to find it.

In the long term, resins will be made from non-oil sources, but it will take many years to organise their availability at acceptable prices and with satisfactory performance.

The defects mainly involved cracking and crumbling and were more common in hotter regions: 80% arose in the south of the USA, with far fewer in New England. Stress was a factor in 75% of cases.

The company also confirmed that expected lifetimes were more than 20 times as great for decking situated in Boston as in Arizona. Laboratory experiments showed that a small amount of antioxidant increased probable lifetimes enormously. By the same criteria, examination of competitors' products showed a wide range of likely lifetimes. Metal stearates and other metallic compounds were thought likely to affect durability, according to the speaker, Anatole Klyosov, the company's Vice President for Research and Development.

Kadant's products used HDPE as the resin.

The number of conferences relating to wood plastics composites (WPC) remains high. On 5-7 December 2005, AMI held its fourth meeting on the subject in Vienna, Austria, just two and a half weeks after Intertech's meeting in Orlando, Florida (14 -16 November) when Hackwell Group spoke about the European market for WPC.

However, interest in WPC is no longer confined to specialist conferences and it is significantly beginning to feature in other programmes too. Professor Geoff Pritchard of Hackwell Group addressed the PIRA's meeting on Fillers, Pigments and Additives in Plastics (4-5 December, Brussels).

Hackwell finds that a growing number of European companies are newly entering the WPC business. Most recently Deceuninck, the integrated, worldwide group specializing in compounds, extrusion, finishing, recycling and production of profiles for use in the construction sector, announced the start-up of WPC production in Europe. Deceuninck (a customer of Hackwell group reports on WPC) had already been making WPC in the US. Initially it will concentrate on production of WPC profiles for decking and cladding, with railing and fencing products likely to follow.
Deceuninck had a very successful launch of its WPC products at the GLEE (International Garden and Leisure Exhibition) trade show held recently in Birmingham, UK.

The conclusion is that the additives business has recovered from a very difficult period but prospects for future growth remain subject to a number of concerns such as oil prices, energy and raw materials costs and Far Eastern competition.

The report contains a great deal of information largely derived from secondary sources up to the late autumn of 2004. Several very recent re-organisations are mentioned but the merger of Crompton with Great Lakes, two of the biggest additives companies, was only announced in February 2005, just as the report was going to press, and it is therefore only mentioned in the introductory section. Compared with most primary–source market research reports, the report is offered at a very competitive price and should prove good value to those who want to get up-to-date with the additives scene.

Brian Hackwell of the Hackwell Group, publishers of market reports on the European wood plastics industry, presented an overview of wood plastics composites (WPC) at RAPRA's (Rubber & Plastics Research Association) conference on High Performance Fillers Cologne, Germany, on March 8 and 9, 2005 (see http://www.polymerconferences.com for details).

The conference covered a wide range of fillers for polymers. Although many of these are mineral, wood qualifies as a "high performance" filler on account of the excellent workability and aesthetics it brings to wood plastic composites. Seen from the other side, polymers provide a high-performance matrix for wood fibres in some applications, as the combination has much lower water absorption and higher durability than traditional timber when used outdoors.

The conclusions were that WPC has a greater environmental impact than wood, and more so when recycled plastics are used to make it instead of virgin plastics. However, the question of how to identify the beginning of the production process is a difficult one, and in this case the energy needed to make the HDPE bottles that were subsequently recycled to make the WPC was counted towards the latter's environmental impact.

The best way to dispose of WPC after use appeared to be incineration with energy recovery.

The UK construction industry is just beginning to learn about wood plastics composites. A first seminar was held in Dundee, Scotland in January 2004, with the forestry industry as the target audience. The programme was repeated, with a few modifications, on 18 October in Watford, southern England for a very different audience. About 130 people in total attended the two meetings.

The WPC manufacturers Knotwood, who use post-consumer HDPE bottles, and Vannplastic, distributors of Ecodek decking, gave presentations after stimulating over-views by Robin Kent of Tangram Technology and Sue Halliwell of BRE. Geoff Pritchard of Hackwell Group spoke on applications and properties, and the green credentials of wood plastics composites were examined by Richard Murphy of Imperial College. There were several small table-top displays, mostly of WPC samples. Unofficial comments on the state of business so far were mixed, some being upbeat and some less so. The prevailing view was that while the WPC industry is not yet ready to take on the window frame market, there are plenty of other opportunities.

For those wanting to know more about how to get certification for WPC products, the talk by Richard Zammitt of BRE Certification (a separate company from BRE) was of keen interest. Bill Corry of Impact Asset Management Ltd spoke about the Recycling Fund. The view was expressed that the WPC industry needs to concentrate more on what the customer wants---competitive prices---rather than draw attention to the environmental virtues of the products, which although appreciated, would not usually clinch a decision.

Harald Zodl of Fasalex also spoke at Addcon on the indoor applications of his company's starch based wood composites. Despite having only 8 employees, Fasalex expects its 2004 turnover to be around 1.3M euro, based on a production capacity of 4000 tonnes a year. Lonza's table top display featured lubricants for WPC.