The open time, wet edge or lapping of a coating is a measure of how much time an air dry coating takes to reach a stage where it can no longer be applied by brush or roller to the same "wet" coating without leaving an indication on drying that the "wet" and newly applied coating did not quite flow together. Therefore, the advantage of having good open time in a stain would result in better general appearance of the stain.
In my previous blog post, I covered the characteristics of microfibrillated cellulose (MFC) and fumed silica as raw materials used for industrial purposes. I focused on how MFC provides a viable alternative to fumed silica in many applications since they both have large surface areas with similar surface active groups. However, the physical network properties of the two materials differ and may lead to new and exciting discoveries in the end products.
Microfibrillated cellulose (MFC) and fumed silica are both used for controlling the rheology of liquid systems, such as thixotropy and stability, and may be used within the same field of applications giving similar properties. However, there are also profound differences between the two. For example, where MFC is a natural product derived from cellulose-based raw materials, the native hydrophilic fumed silica is an amorphous, colloidal silicon dioxide prepared by a flame hydrolysis process. So why can two such, at first glance, different products be used in similar applications? In this blog post, I will dig more into detail about the two multifunctional additives, and discuss how their similarities and differences may affect application properties.