SciMed Education
How to best Measure Silicone Coating weight on Paper and Plastic - Advanced Techniques
Silicone coating plays a crucial role in various industries for enhancing the performance and functionality of specialty paper and plastic products, including release liners, hygiene products, medical and food packaging, tapes, and much more.
It often goes underappreciated how this important coating provides a range of benefits that improve both the usability and durability of materials, from adhesive resistance, moisture and contamination protection, and resistance to environmental factors such as humidity, heat and UV protection.
To maximize these benefits, it is vital for manufacturers to carefully monitor the thickness of silicone coatings applied, which is essential for maintaining high standards and meeting industry-specific requirements.
The coat weight of silicone, expressed in grams per square meter (g/m²) or pounds per ream, is a key quality parameter, and accurate measurement of silicone coating weight is necessary to avoid waste from over-coating or the risk of product rejection due to under-coating.
This article explores the methods and technologies available for measuring silicone coat weights on paper and plastic materials.
How can I accurately measure silicone coating weights on paper?
Older methods for monitoring silicone coating weights on paper include weighing samples before and after coating (gravimetric method), or even direct manual measurements using a micrometer or caliper.
In a high-throughput production environment these outdated methods are time and labour intensive, and simply no longer practical.
Thankfully modern analytical methods such as non-destructive X-Ray Fluorescence (XRF) analysis provide rapid and accurate measurements to suit today’s industries.
How can I track the silicone coat weight on paper using XRF technology?
The RIGAKU ED-XRF systems utilise high-performance semiconductor detector technology. This advanced method eliminates the need for helium purge gas and significantly reduces analysis times. With sharp peak detection capabilities, it accurately distinguishes silicone from other materials, like clay coatings, ensuring efficient and cost-effective quality control.
The RIGAKU NEX-QC series instruments offer rapid and precise measurement of silicone coat weight in as little as 20 seconds, and offer monitoring of ultra-low coating weights down to 0.0005 g/m2
Users can further enhance the measurements of their materials using specific reference samples for calibration and/or the in-built validation feature to ensure silicone coat weights remain within precise specification tolerances.
Is it possible to measure silicone coating on clay coated paper?
It is increasingly common for silicone coated paper products to also first include a clay coating. This refined clay fills the gaps between fibres in the paper, which improves the smoothness of the finished paper, and improves opacity and brightness.
The challenge for manufacturers is that clay coating can vary and the effects of this can compromise the measurement of the subsequent silicone coating weight.
Older XRF systems use a gas-filled proportional counter (‘prop counter’) that yield very broad peaks, making it difficult or impossible to discern the silicon X-ray signal from the aluminium in clay coated papers, thus compromising the accuracy of the silicone coat weight measurement.
The RIGAKU NEX QC systems use more advanced semiconductor detector technology that facilitate sharper resolution of both the silicon and aluminium peaks.
Moreover, the in-built RIGAKU clay correction feature automatically adjusts for variations in clay coat and composition with no need to tare for each sample or new paper roll. This automatically maintains precise measurement of the silicone coat weight, offering an invaluable tool for quality control and optimising production quality while reducing costs.
Can silicone coating on plastic and plastic food packaging be measured accurately using XRF?
Silicone barrier coatings, such as those to protect against moisture or oxygen ingress, or release coatings on thermos-formed plastic packaging are typically required to be very low weights (i.e., <0.2 g/m2).
The RIGAKU NEX QC systems have superior sensitivity making them ideal for ultra-low silicone coating weight measurements down to 0.0005 g/m2.
By utilising a set of calibrated thin plastic standards and measuring in an air atmosphere this allows for fast and accurate determination of silicone coat weight on plastic and plastic food packaging.
Can silicone coating weight be measured on-line in real-time?
Alongside the NEX QC series, RIGAKU offer the high-performance NEX LS online XRF system.
The NEX LS offers real time cross and machine direction silicone coat weight profiling, enabling 100% quality control throughout the whole roll with minimal user set-up.
Real time measurements can be taken in as little as 0.1 seconds, meaning any quality issues can be detected and immediately rectified with minimal loss of time or wastage.
The NEX LS is also not fazed by variations in substrate colour or clay coatings thanks to in-built, automated correction functions, making this the ultimate tool for quality control in the most demanding production environments.
Conclusion
Accurate measurement of silicone coating weights on paper and plastic is crucial for maintaining product quality, optimising production costs, and minimising waste.
Advanced XRF technology, particularly RIGAKU ED-XRF systems with semiconductor detector technology, provides a reliable, fast, and precise method for such measurements. Solutions are available for both benchtop and online instruments to support a variety of industry requirements.
This technology not only improves efficiency in the production process but also supports the industry’s need for quality control and sustainability efforts.
What to do next?
For further information on silicone coating measurements and our advanced analysis systems, please visit the NEX-QC, NEX-QC+ and NEX LS product pages. Our specialists are readily available to address any inquiries you may have about these products.
Contact Us Today
We take great pleasure in assisting you and ensuring you get a prompt response to your questions
Live chat opening hours Mon – Fri 9:15 to 16:30 (UK Time)