Products - 15th March 2016

Viscosity. It’s all around us and it affects us every day without us even realising it. Many a bacon sandwich has bared witness to attempts of beating tomato ketchup from a bottle or the poor hair conditioner bottle that has had its life squeezed out of it to get the last remaining soapy residue. Viscosity is a menial challenge that’s easily overcome on a day to day basis, but for a polyurethane chemist or formulator, we can quite literally be stuck in the thick of it!

Now, this is where it gets tricky. In both of the situations above, water could potentially be added to reduce viscosity and help make life easier. Water is an excellent solvent and we are very fortunate of its abundance on Earth. Unfortunately, water and polyurethane prepolymers get on a little too well and the mood can quickly turn quite, well, bubbly so to speak. Organic solvents are used instead; these are typically aprotic in nature (i.e. not reactive towards isocyanates) and offer excellent viscosity reduction at relatively low addition levels. The problem with most solvents is that, at room temperature, they have no trouble getting up and leaving. Their hasty departure, due to evaporation, places them into a category of chemicals called ‘volatile organic compounds’ (aka VOCs).

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VOCs pose a significant health and environmental risk and legislation certainly makes them unfavourable. Plasticisers are increasingly being used as an alternative to solvents, but on their own, they just don’t cut it. While plasticisers do indeed help to reduce the VOC content of a resin system, the level of viscosity reduction is inferior to that of solvents. In addition to VOCs, another health risk associated with polyurethane prepolymers is unreacted isocyanate monomer. Polymer reformulation and distillation are methods that can be used to reduce residual monomer, but can increase viscosities through chain extension and side reactions. This is where Incorez comes to the rescue!

Incozol LV is an oxazolidine manufactured by Incorez. Oxazolidines are versatile additives for both 1K and 2K polyurethane systems. They hydrolyse upon exposure to moisture to yield amino-alcohols that readily react with isocyanate groups. Earlier I mentioned that water and isocyanates get on a little too well. Through the addition of oxazolidines, the water/isocyanate reaction is eliminated, no carbon dioxide is generated and the result is bubble-free coatings. The added benefit, though, of Incozol LV is that due to its inherent low viscosity it is classed as a reactive diluent. Upon addition, it will assist in reducing the viscosity of your formulated system, and more importantly, help to reduce VOCs.

So there you have it, it’s not the end of the world when it comes to trying to save it. Incozol LV offers formulators the potential to reduce VOC emissions which in turn may help future generations live and breathe a little better.

Kirk Booth
R&D Chemist

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