MATERIALS | TECHNOLOGY UV FILTERS
In a nutshell: researchers find new source for organic UV absorbers
An international research team has used cashew nut shell liquid (CNSL) as the basis for new types of organic UV filter, which can be used as a plastics additive. The cashew nut shells
are left over from the production of cashew nuts, so are a waste product. The researchers, from Johannes Gutenberg University Mainz (JGU) in Germany, the University of the Witwatersrand in Johannesburg in South Africa and the University of Dar-es-Salaam in Tanzania, say the CNSL acts as a substitute for petroleum in the synthesis of the filter. UV radiation is a typical cause of damage to paints,
ADDITIVES Clay synergist FRs cover multiple materials
Tolsa has extended its Adins range of flame-retardant (FR) additives for PP, PVC, rubber polymer systems, and silicones, and will highlight them at K2019. The new clay synergists reduce
smoke production and improve heat release in PP, PVC, and rubber polymer systems, in addition to the existing FR additives used in other polymers.
“Our unique FR technology continues to evolve and we see continuing growth for clay synergists in a wide range of systems that require the highest standards of flame retardancy,” said Antonio Esteban, technical manager for special addi-
www.pipeandprofile.com
tives at Tolsa. “Our materials are highly versatile and can be fine-tuned to meet the high-performance needs of formulators and end users.” The expanded product line includes a new grade that uses titanium dioxide to improve the performance of intumescent systems for PP and coatings. It further stabilises the char in intumescent systems (at dosages of 1-2%), improving the flame-retardant efficiency. In intumes- cent systems, Adins clay decreases and delays the peak of the heat release rate and acts as a smoke suppressor. It can improve cost efficiency of formulations with intu- mescent flame retardants.
Key end-use applications include
transportation, pipe, coatings, and wire and cable. Tolsa has also introduced Adins
Clay Sil1, which is used in silicones and PVC formulations, delivering reduced heat release and smoke suppression. It is an effective alterna- tive to antimony trioxide (ATO), thus easing environmental concerns. The company is also looking to
translate its FR technology to other polymer matrices including nylon, polycarbonate, and thermosets. n The next issue of PPE will include extensive coverage of new materials at K2019. �
www.tolsa.com
September 2019 | PIPE & PROFILE EXTRUSION 55
Charles de Koning from Johannesburg, used CNSL as a renewable starting material for the production of new UV filters. CNSL is produced in large quantity during the production of the nuts and cannot be used as food or feed., so there is no competition between its use as a chemical raw material and the production of foodstuff.
Using CNSL can be
coatings and plastics. A typical way to protect against this is to add UV filters to the formulation. These can either be mineral pigments such as titanium dioxide or organic com- pounds. Currently, both classes of
UV filters are under fire for different reasons, say the researchers – with some organic filters being toxic to aquatic life. At the same time, most organic filters are produced from petroleum. The researchers, led by Till Opatz of JGU and
regarded as an example of xylochemistry – in which woody biomass serves as the carbon source for chemical synthesis. The research was published in a recent edition of the European Journal of Organic Chemistry. �
www.uni-mainz.de
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