Emulsion Polymerization Applications
SEKISUI’s Selvol™ polyvinyl alcohol resin is an excellent emulsifying and dispersing agent for an array of materials. In fact, it’s one of the most common polymers for colloidal stabilization of vinyl acetate-based emulsions.
By using PVOH in the preparation of adhesives, your final product will have a variety of properties:
- Better adhesion to hydrophilic substrates
- Good machinability
- Easy cleanup
- Good wet tack
- Rapid setting speed
- Good heat resistance
- Low degree of blocking
- High thickening response
- Crosslinkability
Below, we look further at its emulsion polymerization applications.
Recipe for Success
Select the Right PVOH Grade To Get the Most Benefit From Your Final Product
Before choosing any of the Selvol™ PVOH grades, you must consider three factors:
- The composition of the emulsion to be produced
- The polymerization conditions
- The final product’s desired properties
Moreover, PVOH molecular weight and hydrolysis levels have a large influence on the emulsion’s final properties. In general, higher molecular weight PVOH grades result in emulsion polymers with higher viscosity, increased shear thinning, higher tensile strength and higher wet tack. Lower hydrolysis levels create good stability, increased water sensitivity and improved freeze–thaw stability.
Tips for Using PVOH in an Emulsion Polymerization
- Small changes in the process conditions and/or amounts of raw materials being charged to the reactor can produce differing emulsion properties, such as viscosity and coagulum levels.
- PVOH must dissolve properly. For complete dissolution of PVOH, please see our Selvol™ Polyvinyl Alcohol Solution Preparation guide.
- When using different PVOH grades, make sure to use the correct ratio. Differences in the amounts of high or low molecular weight grades can influence emulsion viscosity.
- Using high hydrolysis PVOH grades results in emulsions with larger particle sizes and lower viscosities than emulsions produced using partially hydrolyzed PVOH grades.
- Selvol Polyvinyl Alcohol 418 is a 92% hydrolyzed grade and can produce stable emulsions with enhanced properties, such as wet tack and faster set speeds for adhesives.
- Selvol Polyvinyl Alcohol 800 grades are better versions of standard grades that SEKISUI specifically formulated for emulsion use. Their benefits include greater cold water solubility, low foaming, reduced gel content and reduced dusting.
