Usually, in the sponge production process, we encounter foaming issues such as rapid foaming, overly large sponge pores, and a lack of fineness. Drawing from years of accumulated foaming experience, we are willing to share some foaming insights and welcome suggestions for improvement.
Adjusting Formulation Ratios: Make adjustments to the formulation by reducing the quantities of MC (Methylene Chloride) and POP (Polyol Polyether Polyol). Pay attention to the TDI (Toluene Diisocyanate) index and select polyether compounds that can slow down the foaming process.
Selecting High-Quality, High-Activity Silicone Oil: Choose high-activity silicone oil, which can lower the decomposition temperature and result in finer sponge pores.
Limiting Catalyst Usage: Reduce the quantity of catalysts to slow down the foaming rate and select blowing agents with relatively weaker expansion effects.
Controlling Stirring Parameters: Precisely control the stirring speed and duration. In the initial phase, employ slow and gentle stirring, as slow as possible but within a reasonable timeframe. After slow stirring, pause for 1-2 minutes to remove any white bubbles. Then continue with slow stirring and, at specific intervals, switch to fast stirring to handle the TDI component. Consider using fan-blade type stirring blades with a hollow center and two or four baffle blades on the barrel’s edge. Ensure uniform stirring speed during both slow and fast stirring phases.