Silicone is a polymer derived from minerals and synthetic feedstocks. It is used in many different end-applications, one of which is as a base for sealant materials. Sealants have the purpose to seal the gap between different construction elements, absorb mechanical impact, act as a moisture barrier and sometimes as a sound dampening agent. To fulfil these purposes, the sealant must be designed to adhere to a variety of materials, have the right modulus (stiffness) combined with movement capability and resistance to degradation from exposure to UV, temperatures and chemicals.
Some silicone sealant formulations contain mineral oil as a plasticiser and this paper shows the performance of different types of oil in terms of compatibility, rheological properties and UV exposure resistance.
An acetoxy-cured silicone sealant frame formulation with a high loading of plasticising oil has been evaluated with different types of oils; naphthenic, paraffinic and biobased, of different viscosities, on several key performance properties such as bleeding, adhesion and rheological behaviour.
The results show that the relatively polar character of silicone polymers has very good compatibility with naphthenic oils, which allows formulations with higher oil loading, enhances the adhesion and reduces the impact of temperature variation in a simulated end usage environment.
Co-author: Emma Öberg