By T.Kealy
Technical Manager - Rheology Solutions Pty Ltd

Surface coatings include such diverse processes as inkjet and screen printing, applying adhesives, paint, varnish and so on. Specifically for the surface coatings industries, materials characterisation is of critical importance in many processes. Fluid related issues like sedimentation, flotation, time related structural decay or build-up (these variables dictate common industry concepts including sag, slump, flow, levelling and cure) and post-cure issues like adhesion and bond strength are rheology based phenomena. These processes depend on fluid rheological parameters such as viscosity, visco- elasticity, creep and recovery, thixotropic tendencies and yield stress, and solid material properties such as extensional behaviour under various loading conditions. Extensional flow properties dominate processes and phenomena such as pouring and filling, tack, misting etc, where stranding occurs and influences time, quality and energy requirements.

The Rheology Solutions applications laboratory has state of the art equipment, capable of measuring the above parameters, and of providing interpretation of the results where necessary. Laboratory equipment includes sensitive, specialised, modern instrumentation and sensor systems, for measuring complex or difficult fluids such as those with very low viscosity, or those with a solid phase, or highly elastic liquids. Solids performance according to various international standards can also be monitored.

Information such as shear viscosity curves, thixotropic behaviour and flow curves may be obtained for interested clients. Additionally, of importance to the industry, when scientifically assessing changes in flow behaviour due to temporal or ingredient issues, viscoelastic moduli as a function of either shear rate or strain can be assessed. Structural changes under very low shear (like in the case of storage, gravity settling, cure etc) or very high shear (pumping, mixing, filling etc) are possible using the advanced equipment and sensors available at the laboratory of Rheology Solutions. These measurements may be obtained as a function of temperature, solids density, or to monitor the effects of changes in modifier/ingredient species or concentration.

With this information the scientist or engineer may change the process, or design new unit operations or products to maximise the potential benefits to be obtained from the physical properties of the processed fluid.

Rheology Solutions is pleased to provide this information to interested parties, and to make our rheological expertise available to the surface coatings community. Our range of testing and interpretation services is further supported by customised workshops, training and seminars to cover the needs of individuals, businesses or industry sectors, covering introductory, intermediate or advanced theory and practice of rheology. This can be supplemented by application specific workshops.

A complete Contract Testing Information Kit specific to the Surface Coatings Industry is available by sending an email to info@rheologysolutions.com and typing "Contract Testing Kit for the Surface Coatings Industry" in subject area. You should receive your kit via post within 5-10 working days.

The Contract Testing Request Form needs to completed and returned prior to any samples being sent. This will allow us to advise you within 48 hours if we require further information. We will then provide an overview of the work we will carry out including an estimate of the projected time scale and associated fee.

For further information, please complete the Information Request Form.

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