Metal detectable plastics and X-ray detectable plastics are commonly supplied to converters/OEM’s and subsequently processed into detectable shapes or final products via methods such as injection moulding, extrusion and calendering.
At Radical Materials we have a wealth of experience in developing custom Metal detectable & X-ray detectable polymers and are a leading producer of Metal detectable & X-ray detectable polyurethane (TPU) compounds to a global customer base.
Foreign body contamination, such as metal, bone, glass and plastics, is a major area of concern for processors & manufacturers in the food and pharmaceutical industries. Should these foreign bodies pass into the consumer chain, they cause significant risk to consumers, as well as financial and reputational implications for the manufacturers. To mitigate this risk, production lines will commonly employ metal or x-ray detection systems at critical control points, however standard plastics & rubbers are generally undetectable.
Have a question? We are always happy to chat, so feel free to give us a call on +44(0)1495211400.
Our X-RAY inspection equipment comes from leading manufacturer, Minebea. This equipment is used in our development lab to guarantee our SCOPIC range of X-ray detectable masterbatches and compounds achieve the highest level of detection possible
Metal and/or X-ray detectability of polymer products is achieved through the incorporation of specific additives at the masterbatch/compound processing stage. The drawback here is that these additives invariably reduce the toughness of the base polymer and so, even though now detectable, actually increase the risk of fragments breaking off in the first place.
Over the years Radical Materials, via the SCOPIC brand, have worked extensively to offer standard polymer masterbatch and compound solutions which help to alleviate such problems by utilising techniques to increase the toughness of the final polymer material. The metal & x-ray detectable additives have been developed to offer extremely high levels of detectability, hence meaning that lower addition levels can be utilised than of other, less detectable, additives which are available. In addition, much work has been focussed on the use of impact modification systems, specific to individual polymers.
Through the use of lower levels of detectable filler materials and the use of advanced flow promotion additives the melt flow characteristics of our materials have been largely maintained. So if you’re injection moulding thin walled parts from SCOPIC detectable nylon 6 or extruding or calendering conveyor belting from our metal and X-RAY detectable TPU, the same tooling and parameters can be used.
This is often an important consideration in detectable polymers components as it can offer an additional level of visual detection against foreign bodies (blue being the most common colour in the food industry). ‘Traditional’ detectable polymers are typically very dark and dull in colour due to the influence of the additives utilised. The additives commonly used in SCOPIC systems allow for the generation of very bright and bold colours in the final products.
Additives utilised have been optimised to give extremely high levels of detectability, giving the opportunity to increase detection levels in the final products or offer comparative detection levels to other additives at lower levels of addition.
SCOPIC detectable masterbatches and compounds are commonly utilised to manufacture polymer components which are used on or in the vicinity of food processing equipment. Some of these components are designed to have varying degrees of direct food contact, whilst others are designed with no direct food contact in mind at all. Regardless of the final application, the fact that detectable polymers are used in and around food processing equipment means that compliance with food contact regulations is a key consideration.
The key factor in detectable polymer products, and one which is unfortunately all too often overlooked, is how detectable the products actually are. Radical Materials can support all projects/developments with full in-house capability to measure, optimise and report on both metal and X-ray detectability.
Metal and X-ray detectable plastics are commonly employed in components used in the food processing environment, helping to reduce the possibilty of foreign body contamination.
Modular conveyor belts are manufactured from many interlocking elements, connected together using rods. They are particularly useful in systems requiring bends and curves. Compounds such as Metal Detectable Nylon, Metal Detectable Polyketone and Metal Detectable POM are most suitable for these applications and can be manufactured to meet customers requirements.
Flexible Conveyor belts are often manufactured from Metal detectable polyurethane (TPU) and sometimes PVC. Detectable TPU compounds can be made using the customers own TPU material and can also have pigments, antistatic additives, X-ray detectable additives and even antimicrobial technologies incorporated.
Plastic wear components are used throughout food production lines, commonly protecting other, more critical components. By their very nature, they are prone to wear and material removal, which could ultimately find its way into the food products.
Detectable cable ties are used for applications such as banding electrical cabling on or in the vicinity of food production lines. Fragments of these ties are capable of being detected by conventional metal detection and X-ray systems used on such lines as part of the Hazard Analysis and Critical Control Point (HACCP) system.
A metal detector consists of three coils, a central transmitter and two outer receivers. The induced currents in the coil arrangement are in balance and generate an electro-magnetic field within the detector, which remains undisturbed until a metallic object passes through causing a disturbance. The effect of this is to change the voltage in the coils, which is then converted to an electronic signal, triggering the sensor/alarm and the rejection mechanism if activated. Metal detectors, as the name suggests, will only detect metal or metal containing foreign bodies and a ‘standard’ unfilled polymer would be totally invisible to such a technique.
The greater the difference in density between foreign body material and food product, the greater the detection sensitivity. A ‘typical’ value for density of food products would be around 1.00g/cm3(water). Due to the make-up of most polymers and the fact that many utilised on a food production line have a density below 1.30g/cm3 (polyethylene and polypropylene are below 1.00g/cm3), this differential is typically not sufficient to allow reliable and repeatable detection of standard polymer foreign bodies.
It is common to simply assume a metal detectable polymer will also show good X-ray detectability. Indeed, ‘standard’ metal detectable polymers will show an increased level of X-ray detectability over the unfilled polymer due to the increase in density caused by the additive. However, this is by no means optimised and good design of a polymer for X-ray detectability requires a special focus and numerous factors to be considered. These would include the design of additive system, base polymer utilised, minimum thickness to be detected as well as all details of the food product(s) in the processing line (density and consistency, size and orientation, nature of containment material etc).
SCOPIC detectable masterbatches and compounds are commonly utilised to manufacture polymer components which are used on or in the vicinity of food processing equipment. Some of these components are designed to have varying degrees of direct food contact, whilst others are designed with no direct food contact in mind at all. Regardless of the final application, the fact that detectable polymers are used in and around food processing equipment means that compliance with food contact regulations is a key consideration.
It is true that it is for the end user of the final article into which SCOPIC masterbatches, compounds and additives are incorporated to determine that any specific and applicable regulatory limitations on use are complied with and that all relevant migration testing and regulatory demands are in-place to allow use in the specific end-use conditions. However, this process is much easier and the masterbatch/compound/additive itself can be used with much more confidence if supported by a sound regulatory declaration under a defined set of conditions.
Common masterbatches/additives have been tested (at higher concentrations than the guidelines for normal usage) and compliance reported for migration limits of relevant substances according to EU 10/2011, under specific conditions listed in the respective declarations. All materials offered comply with the requirements of the Framework Regulation: Regulation (EC) No 1935/2004 on materials and articles intended to come into contact with food, as amended
Rather than relying upon generic statements, it was again decided to provide a worst-case and more meaningful approach by performing actual migration testing on the range of detectable additives utilised in Scopic solutions. Again, specific conditions of test are described in the full reports, but results indicated that, under these conditions, all additives would meet the regulatory requirements for 21 CFR 170.39 ‘Threshold of regulation’ for substances used in food-contact articles.
All statements and conditions are available on request and help to support the regulatory assessment of the final product.
A large proportion of our work is the development of custom solutions, often outside the scope of our standard product range. We relish a challenge, so feel free to test our capabilities..
With the on-site capabilities and facilities, Radical Materials are able to support small to large custom developments from lab scale all the way up to full production.
A wide suite of test facilities are available to support developments. These include mechanical tests as well as properties such as thermal conductivity and surface resistivity.
A wide suite of test facilities are available to support developments. These include metal and x-ray detectability as well as the evaluation of properties such as mechanical strength and UV-C stability.
A continuing focus on new and novel technologies to bring advantages and progression to conductive polymers.
Conventional unfilled polymers will not be detected by metal detection systems. Due to the low density of these materials then, depending upon conditions, it is often extremely difficult for an X-ray system to differentiate them from food products and reliably detect them.
Engineered additives and additive blends are incorporated into the polymer during the compounding stage. Some additives focus on metal detection performance, whereas others are specific for X-ray detectability.
A heated cathode generates electrons, while a high voltage between the cathode and anode accelerates these electrons towards a tungsten disc. Upon impacting the tungsten disc, the electrons are slowed down and subsequently generate X-rays.
The X-ray beam passes through the product(s) and is absorbed at differing rates determined principally by product/foreign body thickness and density. The transmitted beam is detected at the opposite side by an array of sensors and thereafter, via several steps, the signal intensity is converted to a grey value. The more X-rays that are absorbed by a particular material, the darker shade of grey it will appear on the final image and the more chance of the machine detecting it against a food product.
The ability to be detected and rejected by an industrial metal detection system, designed to sense to varying degrees ferromagnetic, non-ferromagnetic and non-magnetic metals.
The ability to absorb sufficient x-rays such that there is a noticeable difference in intensity (grey value) in the final image between a foreign body and food product. When metal/x-ray detection systems are used effectively in the food/pharma processing industries, these properties help to reduce foreign body contamination by sufficiently detectable materials.
Metal detectors are perfect for detecting metal foreign bodies, but are limited to this type of material. X-ray inspection technology has the capability to detect a much wider range of materials/contaminants than metal detectors, including metals but also the like of glass, ceramic and bone.
Any applications where there is a risk of small fragments entering the production flow e.g. tags, straps, pallets, seals, conveyor belts, cable ties etc. These fragments need to be detected to minimise the risk of them entering the consumer chain.
Radical Materials Ltd
Unit 10, Rassau Industrial Estate, Ebbw Vale, Gwent NP23 5SD, United Kingdom
+44 (0) 1495 211400 info@radicalmaterials.com
SCOPIC® & KONDUCT® are registered trademarks of Radical Materials Ltd. AIRSENTIAL® is a registered trademark of Radical IP Ltd.
Radical Materials is presently working on a project aimed at developing performance polymer compounds to provide EMI/RFI shielding solutions in moulding/extrusion applications. This project is being undertaken with financial support from the ERDF via the SMARTCymru 2014-2020 West Wales and the Valleys Operational Programme.