Sealing deal for Sealants

Producers of silicone sealants need look no further. Nynas has developed a range of specially designed silicone fluid alternatives that are cost-efficient and offer the right balance in formulations between viscosity, colour stability and volatility.

Used in a wide range of applications, primarily within the construction sector, silicone sealants are in great demand. However, there is a problem. Silicone is in short supply. Together with the continued strong demand, the tight global supplies of silicone are driving up prices. Hence, producers of silicone-based products are eager to find compatible and cost-efficient alternatives.

Nynas oils can be used to partially replace silicone fluids, reducing manufacturing costs. Specially developed for the sealants market, Nynas alternative products to silicone fluids performed very well in a recent comparative study.

“It is important to find the right balance between three performance criteria – compatibility, loss of mass and colour stability,” says Emma Öberg, Development Engineer at Nynas.

Compability is important; if it is not good enough you end up with bleeding on surfaces. Oils of lower molecular weight have lower viscosity and will be more compatible with the polymers used in silicone sealants. However, such oils are also more volatile which is not good in terms of loss of mass or shrinkage. The colour stability benefits from both lower molecular weight and low aromatic content.

“In our study, in which we compared our naphthenic oils with paraffinic oil, we found that the solvent power of naphthenic oils allowed us to opt for higher viscosity without loss of compatibility. We concluded that up to 25 % of our process oils can be used with good results and no bleeding in silicone sealant formulations,” says Emma Öberg.

The hydro-treatment technology used by Nynas to refine naphthenic oil also ensures that the products are odourless, almost colourless, and offer very strong UV stability.

“Our NYFLEX® range of alternative products to silicone fluids ensure the best compatibility and offer a cost-efficient and high-quality option that helps to bridge the supply gap,” says Ghislain de Quatrebarbes, Market Manager, Chemical Industry, Nynas Naphthenics.

“Nynas is also able to offer silicone sealant manufacturers a reliable supply and just-in-time delivery on a global scale,” he adds.


Striking the right balance

• NYFLEX® 2120B is the latest addition to Nynas range of alternative products to silicone fluids. It has been specially designed to meet industry requirements in terms of compatibility and cost-efficiency, and it strikes a good balance between compatibility and colour stability.

• Formulations made with the oil and two other products in the NYFLEX range, of varying viscosity, were compared with formulations made with paraffinic oil or silicone fluid (polydimethylsiloxane, PDMS). The formulation tested was for an acetoxy curing silicone sealant using 25 wt% of process oil.

• Nynas study shows that the loss of mass at high temperatures is primarily dependant on the volatility of the oil. Process oil of low viscosity will have an inherently higher volatility. The level of exudation at cold temperatures is mainly due to the compatibility between the polymers of the silicone and the fluid. Generally, low viscosity oils are more compatible.