All x-ray detectable plastics are not equal…
It appears that many x-ray detectable plastics are designed to a price point, rather than to detectability targets.
A few of our customers for metal & x-ray detectable plastics had struggled with alternative materials for a while before approaching us, and there seem to be two recurring issues that typically led them to switch…
Some x-ray detectable plastics simply don’t work.
A while ago, we compared three different detectable plastics with our Minebea Dylight. All three were moulded from the same base material and they were passed through the Minebea in a tub of sugar. The results are shown in the photo above.
The middle disc was made with one of our SCOPIC metal and x-ray detectable plastic masterbatches. Very obviously detectable.
The barely discernible disc on the left was a customer’s standard product. Despite being marketed as x-ray detectable, it was missed by the detector (there’s no blue/red square around it indicating detection). That said, it’s by no means the worst we’ve seen 🙁
The right hand disc was moulded with a competitor’s masterbatch. It is only marginally less x-ray detectable and would appear to be a good alternative to SCOPIC. Or was it?
Some x-ray detectable plastics have severely compromised physical properties
Detectability is obviously important, but often overlooked are the implications of detectable additives on mechanical & functional performance. Improving the detectability of a component is of limited value if the component is then so mechanically compromised that failure becomes a certainty rather than a remote possibility. As a matter of course, we subject modified materials to a series of tests to ensure they remain within the required performance parameters.
Watch the video below for a nice example of a truly awful x-ray detectable plastic (ABS) one of our customers was using for some years before approaching us.
Have you encountered products that are mechanically compromised by their detectable additive?
They really don’t need to be… and at Radical Materials we can help make sure of that.
LEARN MORE ABOUT SCOPIC DETECTABLE MATERIALS >>
READ MOREUnderstanding the impact of functional additives on your materials
Whilst it is always encouraging to see the positive effects of functional additives on the antimicrobial performance of a polymer solution, it is also important for many final applications to consider how the use of such additives might affect the overall mechanical performance of the base polymer.
Radical Materials have the in-house capability to mould test pieces from your exact compound or polymer/masterbatch combination and assess the influence of the additive on the base polymer performance via two principal methods:
- Tensile testing – a fundamental materials test in which a standard specimen is subjected to a controlled tension until failure. The results from the test are commonly used to select a material for an application, for quality control, and to predict how a material will react under normal forces. Radical Materials utilises a 10kN tensile testing machine and associated software capable of testing, analysing and reporting on properties such as yield/ultimate tensile strength and elongation to failure etc. The information obtained from such testing allows for tensile characterisation of polymer samples and analysis of the effect of functional additives on base properties.
- Impact testing – utilises the kinetic energy of a falling pendulum hammer to break a standard test specimen, in order to determine the energy required to do so. The resultant data gives a measure of impact toughness and can be used to report comparisons between different materials and the effect of functional additives on this property. Radical Materials can perform testing and report to both Izod (test specimen clamped vertically) and Charpy (test specimen rests horizontally) test methods.
Whilst it is important to get an understanding of the impact of functional additives on the mechanical performance of base polymers, it can also be crucial to consider how external factors can affect the performance of the polymer solution in service. One such common influence is the effect of weathering, when components are utilised outdoors or simply exposed to UV light. The bulk of degradation of polymers in outdoor applications is caused by the effects of UV light and forms of damage can include colour changes, cracking, embrittlement, blistering etc.
Radical Materials utilises a QUV accelerated weathering tester to reproduce this damage and also accommodate for the additional impact of rain/dew. The system simulates the effects of natural sunlight using high intensity fluorescent UV lamps and is, in a few days or weeks, able to reproduce the damage that can occur over months of exposure outdoors. Visual changes can be quickly assessed against a reference standard and effects on mechanical performance confirmed utilising the test equipment described above.
It is important to recognise not only the positives functional additives can bring to a polymer solution, but also that there may occasionally be unforeseen side effects. It is also important to consider the effects of the operating environment on long-term performance. Aided by investment in a comprehensive suite of test capabilities, along with in-house knowledge and experience, Radical Materials can help to identify, and potentially mitigate, any such effects.
FIND OUT MORE ABOUT OUR IN-HOUSE TESTING CAPABILITIES >>
READ MOREPolymer foreign body contaminant detection in the food processing industry
Foreign body contaminants in food products is a major area of concern for food processors/manufacturers. Examples of foreign body inclusions are fragments of metal, bone and glass as well as plastics and rubbers, which find their way into the food production chain from products/equipment/machinery used as part of the processing line. Should such foreign bodies pass through into the consumer chain, then there is significant risk to consumer health as well as huge financial and reputational implications to the manufacturers. Such incidents are reported in systems such as FSA (Food Standards Agency) report and RASFF (Rapid Alert System for Food and Feed).
To combat the issue and comply with HACCP (Hazard Analysis and Critical Control Point) requirements, production lines will employ detection systems at critical control points, these commonly being metal detectors and/or X-ray systems. The difficulty with commonly utilised standard plastics and rubbers is that they possess neither the electrical/magnetic properties to be detected by metal detectors, nor typically the density to be differentiated from food products by an X-ray system. Standard plastics and rubbers are used extensively in machinery and products within food production lines and, as foreign body particles, are often totally undetectable by conventional systems.
It is possible to enhance the detectability of standard polymers, but early revisions relied purely on visual detection to try and prevent foreign body contamination. Polymer products were (and commonly still are) coloured blue to render them easier to visually detect on a food line due to the lack of naturally occurring blue in the bulk of food products.
Further enhancements around the design of filler/additive systems lead to the introduction of modified polymers, detectable by conventional metal detection systems. This still remains as probably the most common format of detectable polymer. A typical balanced coil metal detector consists of three coils, where the induced currents in the coil arrangement are in balance and generate an electro-magnetic field within the detector. This remains undisturbed until a metallic object passes through, causing a disturbance and triggering the sensor/alarm and rejection mechanism. The required additive system in such polymers must be specifically engineered to achieve the optimum response to industrial metal detectors at the lowest possible addition rate, such that other properties are not too significantly affected.
Moving on from metal detection systems, X-ray detectors are becoming increasingly popular in the food industry. Compared to metal detection systems, they have the advantage that they primarily rely upon density differences between food product and foreign body and hence are able to detect a range of additional foreign bodies such as glass, ceramic and bone. Once again, it is possible to engineer polymers such that they are potentially detectable against a range of food products via X-ray systems, but a different set of additive systems are applicable and, for optimum performance, this requirement needs to be treated separately to metal detection.
Polymer materials are and will continue to be used extensively throughout machinery, equipment and products within food processing lines. Components are typically manufactured by techniques such as injection moulding, compression moulding, extrusion or machining. Fragments of these polymers falling into the food line is a real risk and, without due consideration, such foreign bodies could pass through existing on-line detection systems and into the consumer chain totally undetected. There are potentially hugely negative implications to the food manufacturer should this happen. It is possible to modify existing polymers such that they offer strong levels of foreign body detection via either or all of the commonly utilised techniques on existing food lines (principally visual, metal detection and X-ray detection). However, there are many factors to consider up-front (type of polymer, final product, food products on the line, detection technique etc) and these need to be utilised fully and carefully when selecting or developing a well designed detectable polymer material.
If you are currently looking for a detectable polymer solution, please contact Chris Vince at chris@radicalmaterials.com or call us on 01495 211400.
READ MOREThermally conductive polymer compounds explained, by Radical Materials
There is a growing demand for thermal management of components, devices and systems in established and emerging areas such as electronics, LED lighting and battery technology/e-powertrain. Metals are traditionally utilised here for applications such as heat sinks, housings and covers, but there are drawbacks and limitations to their use and alternative materials offering new design advantages are increasingly sought after. Thermally conductive polymers are a potential candidate that can operate successfully in this arena if designed and utilised correctly.
In order to take advantage of such benefits, the thermal conductivity of standard base polymers needs to be increased. Such an increase can be achieved by incorporating high thermal conductivity additives via compounding/mixing techniques. There are, however, many considerations in order to achieve a successful outcome. These include:
Particle geometry/aspect ratio – will affect overall thermal performance and can lead to anisotropy in the end components.
Particle size – an important factor influencing thermal performance as well as processing and mechanical properties.
Electrical properties – additives can be divided into those that are largely electrically insulating (ceramics/minerals) and those with varying electrical conductivity levels (metals and carbon-based).
Addition rate – increasing additive levels will lead to a corresponding increase in thermal conductivity. However, this needs to be balanced out with the processability and
By careful consideration of polymer compound design, in conjunction with processing optimisation, operational conditions and final part design, thermally conductive polymers can potentially replace traditional materials such as metals in thermal management applications.
Radical Materials develops new detectable polyketone
Metal detectable polyketone polymers are a specialized type of thermoplastic material that contains metal additives or pigments, making them easily detectable by metal detectors. These materials are commonly used in applications where it’s crucial to prevent foreign objects from entering the production process, such as food processing, pharmaceutical manufacturing, and medical device production.
Originally developed in the 1970s, polyketone was first commercialised in the mid-90s by Shell under the Carilon trade name. It has historically been an under-utilised polymer despite its unique properties, with Shell, the main global manufacturer, ceasing production in 2000. In recent years, the escalating cost of polyamides has created significant interest in alternative polymers, of which polyketone is a prime candidate. In 2015, Hyosung began commercial production and they remain the only producer of polyketone.
Polyketone is an extraordinarily useful material, with excellent physical properties and exceptional chemical resistance. A perfect alternative for polyamide, it also has a coefficient of friction equal to that of polyoxymethylene (POM), making it ideal for components subject to sustained wear, such as gears and guides. The material’s unique properties, combined with ready availability due to Hyosung’s continued investment, have generated a significant resurgence in interest among companies manufacturing equipment for the food processing industry.
Radical Materials is a well-established supplier of metal and x-ray detectable additives for materials including polyamide, polyurethane and POM, under the SCOPIC® brand. These additives allow material contaminants in food to be identified by existing magnetic or x-ray detection systems, significantly reducing the possibility of contaminated food leaving the production facility and reaching the consumer.
While standard SCOPIC® additives & masterbatches are available for most materials, polyketone presents a variety of challenges, such as the cross-linking effect of excessive shear forces during compounding. Following extensive trials with an array of filling materials, Radical Materials has developed a formulation specifically for polyketone which avoids these inherent complications and provides detectability equal to that of SCOPIC® polyamide additives. This new benefit, alongside the extremely low moisture uptake, abrasion and chemical resistance, further reinforces polyketone’s position as a viable alternative to polyamide or POM.
If you are currently looking for a heat management application for your polymer compound products, please contact Chris Vince at chris@radicalmaterials.com or call us on 01495 211400.
Nano-additives for electrically conductive polymers
A brief introduction to the application of nano-additives in electrically conductive polymers.
Radical Materials have the in-house capability to mould test pieces from your exact compound or polymer/masterbatch combination and assess the influence of the additive on the base polymer performance via two principal methods:
For certain applications, it is often desirable to combine the traditional advantages of polymers with electrical conductivity ranging from static dissipation through to conduction and EMI/RFI shielding. Applications for such polymers are evident in industries such as automotive, aerospace, defence, electronics and battery technology.
There are a range of additives available in order to impart the necessary level of conductivity, however, many of these require very high loading levels, particularly if high conductivity levels are required. The use of carbon nanotubes (single or multi-wall) can facilitate the achievement of high performance dissipative or conductive polymers at very low electrical percolation thresholds (low loading levels) and can bring added benefits in downstream processing and mechanical performance.
The use of such performance additives does, however, require an in-depth knowledge and optimisation of processing characteristics and of the final application. With such low loading levels possible in order to achieve the desired results, high levels of nano-additive dispersion must be achieved at all stages of processing. Compounding conditions must be optimised as well as final part design, polymer selection and processing (e.g. injection moulding) settings.
The use of additives such as carbon nanotubes can be a highly successful method of imparting wide-ranging electrical conductivities to polymers at potentially very low levels of loading. However, their use requires strong processing know-how and failure to optimise conditions and designs can often result in performance falling well below expectations.
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