Good vibes for antivibration

Antivibration rubber made with naphthenic process oils showed promising results in a comparative study conducted at Nynas Rubber Compounding Lab.

With the motto of always finding the best possible solution for their customers, Nynas’ specialists are conducting in-depth studies in the multifaceted and varied field of technical rubber, targeting one application at a time.

“In one of our recent studies we looked at rubber materials in antivibration applications, and the results show that naphthenic process oils perform very well,” says Dr Kamyar Alavi, Senior Specialist, Tyre and Rubber Oils, Nynas Naphthenics, who leads the team dedicated to the rubber market.

Widely used in antivibration applications, rubber materials form essential parts of vibration damping assemblies. For this particular study, the Nynas team used a rubber compound based on natural rubber as the polymer and carbon black as the filler.

“We made compounds for rubber mounts using a number of different rubber oils as plasticisers – especially focusing on the results obtained from two oils of naphthenic character and two of Group I refinery origin – in order to compare their performance,” says Kamyar Alavi.

“Our results show that by using naphthenic process oils in their antivibration rubber formulations, customers can achieve the same, or even improved, performance compared with Group I based alternatives. NYTEX® 4700 showed the same performance as that of DAE, while at the same time offering game-changing improvements in the health, safety and environmental (HSE) area,” he explains.

In addition, the researchers found that NYTEX® 820 displayed the best damping performance, highlighting its potential as an alternative to SN 500, among other oils, in this application.

The results of the study confirm the high performance of naphthenic rubber process oils, previously seen also in other areas of the rubber industry, and especially in the tyre industry. The study, like other similar ones carried out in the Nynas Rubber Compounding Lab, supports the company’s focus on finding low PAH (polycyclic aromatic hydrocarbons) alternatives without the need to compromise the performance.

A safer damping alternative

• The Nynas naphthenic process oils NYTEX 820 and NYTEX 4700 were used as plasticising oils in the rubber compounds alongside DAE and a paraffinic oil, SN 500, see Table 1.

• The Mooney viscosity of the compound with NYTEX 820 had a significantly lower value, which is beneficial for processing. The compound with NYTEX 4700 also had a longer scorch time (TS2), offering improved process safety.

• To predict the rubber materials’ damping performance, the dynamic stiffness and loss factor were measured for the compounds. The results, in Figure 1, show that NYTEX 820 had the lowest dynamic stiffness and the highest tan δ, while the performance of the paraffinic oil, SN500, was in the reverse order.

Dr Kamyar Alavi is a Senior Technical Advisor and Senior Specialist at Technical Development and Market Support, Nynas Naphthenics. He joined Nynas in 2010.