Plastics & Recycling

Continuing our investment in growing our footprint, Oakbank Solutions is committing to buying and increasing our assets in the purchasing of machinery which we believe will help the company grow and also allow us to join the ranks of companies looking to change materials into new products to prevent waste of potentially useful materials, reduce the consumption of fresh raw materials, reduce energy usage, reduce air pollution and water pollution by reducing the need for “conventional” waste disposal, and lower greenhouse gas emissions as compared to plastic production.

Oakbank was formed to capitalise upon the significant growth in the generation of biproducts from plastics reprocessing operations within the UK and Europe. Plastics reprocessing across Europe are experiencing quick growth in recent years with bigger and more advanced plants being built. At the same time, customer standards are increasing which results in more waste plastic known as bi-products being generated from reprocessing. Waste has historically been exported to far reached countries. Now with standards being raised globally for imported waste across all regions, is reducing the amount of plastic ‘waste’ being exported to these areas.

Oakbank is able now to accept various plastic and aluminium waste products into our reprocessing site in the south-east and our new location in Lincolnshire where the material is sorted and processed into a product.

Materials collected and processed as recyclables rarely come back from manufacturers as the same product. Some uses seem superior to others, a sentiment expressed by the phrase “highest and best use,” which used to refer primarily to energy conservation but now is used more broadly. Referring to resources, some uses directly reduce demand for virgin materials, whereas others essentially create unneeded products that do nothing to reduce the consumption of virgin materials. Many recycled-content products are themselves essentially unrecyclable. Based on these kinds of considerations, at least three different product outcomes can be observed, namely, primary, secondary, and tertiary reprocessing.

As applied to plastic packaging, primary reprocessing produces new packaging; secondary reprocessing produces new items that are usually not practically recyclable themselves because of reduced polymer purity and the lack of collection infrastructure; tertiary reprocessing uses high heat or industrial chemicals to break plastic products into their chemical components, some of which can then, in theory, be made into new products.

This entails remanufacturing the recovered product back into the same product. An example is recovered aluminium cans made into new aluminium cans, or a recovered clear glass bottle made into a new clear glass bottle. In theory, all six of the six resin types used to make packaging plastics are candidates for primary reprocessing. However, primary reprocessing is rare.

Two chemical properties make it difficult. One is plastic’s sensitivity to heat and handling. Plastic molecules are long and flexible, and they change structurally when subjected to thermal and mechanical stress during melting and extrusion. The molecules interconnect and stiffen, and the plastic becomes weak and brittle. This type of degradation is called “heat history” in the plastics recycling trade. The deterioration accumulates with each reprocessing and is irreversible. In contrast, glass and aluminium, composed of short, robust molecules, are not as sensitive to heat and handling and therefore can be reprocessed many times.

The second chemical property that makes primary reprocessing difficult is that plastics are very susceptible to contamination. If sorting is imperfect, resins may mix with other kinds of organic debris when melted. Mixing leads to defects and disruptions in the molecular structure which, in turn, leads to degraded properties. In some cases, contamination leads to the total breakdown of the polymer.

For example, even trace amounts of polyvinyl chloride (PVC) destroy polyethylene when the two are melted together. An analogous problem is found with glass, which is extremely sensitive to ceramic contamination. With plastics, however, potential contaminants are more plentiful and much more difficult to control. Separating plastics is particularly problematic because there is little variation in physical properties (such as density and solubility) to use in sorting. Also, the six basic types of plastic resin include multiple grades and colours within each resin type, and often several resin types are used to make a single container. Primary plastics reprocessing is therefore strongly limited by the chemical properties of the material.

Reprocessors that make plastic containers out of other plastic containers typically blend virgin resin with the recycled resin to boost the product’s performance. One study reported that it is possible to make containers with recycled contents of up to 50% if the reclaimed containers used are themselves made of pure virgin resin. At least one blow-molder was also able to produce a 100%-recycled content bottle with the desired properties using a particular blend of post-consumer resins. However, large-scale reprocessors have found that using more than 15% to 25% of post-consumer feedstock reduced the strength of their containers.

This is the most common type of plastic reprocessing in the USA. It uses recovered plastics to produce new items that are usually not recyclable themselves. Secondary reprocessing reduces the quality of the polymer if it reduces its purity. Accordingly (and largely theoretically, since the industry is very new), feedstock does not have to be as pure as for primary reprocessing. Principal products made by secondary reprocessing include textiles, panels, pallets, and plastic lumber.

Secondary reprocessing sometimes diverts material from landfill and sometimes decreases the use of virgin material. For example, if there is a market for a jacket filled with polyester fibre, and that jacket’s filling is made from post-consumer bottles, then the bottles are diverted from landfill and the virgin resources that otherwise would have been used to make the fibre are conserved.

In plastics recycling, secondary reprocessing differs from primary in the following respects.
 It reprocesses materials in such a way as to render them less recyclable or unrecyclable.
 It is less likely to be the highest and best use.
 It does not usually reduce the production of plastic packaging from virgin resources.

A comparison of the material flows for alternative plastic disposal schemes (reuse, primary, secondary reprocessing) is shown below. Primary and secondary schemes take material back into the “production” section for the reprocessing operation. All three schemes are based on the same volume of use indicated by the thickness of the material flow arrows in the “use” section. The amount of material produced and wasted increases going from reuse to primary to secondary reprocessing. An interesting point shown in the figure is that secondary reprocessing (the most common type of plastic reprocessing in the US) does not form a closed loop.

We have experience in installing plastic chambers, made from GRP or HDPE, they are quick and easy to install and very safe to handle due to their lightweight. The chambers we have used are stackable with the ability to cut duct entry points, as required to meet the project specifications, making preformed plastic chambers extremely versatile. Plastic manhole sections are immensely popular as telecom chambers as they can simply be laid on the well-compacted ground and backfilled and fit the telecom cover.

We have experienced operatives in the major works drainage division who work on installing manhole chambers/covers (plastic, metal, cast iron) daily. Our teams are fully competent in using CAT & GENNY / Sonde equipment to locate other services to avoid any damages leading to outages.