Emulsion Polymerization Applications
Selvol™ Polyvinyl Alcohol is an excellent emulsifying and dispersing agent for a wide number of materials. It is one of the most used 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 such us:
- Improve adhesion to hydrophilic substrates
- Good machinability
- Easy clean-up
- Good wet tack
- Rapid setting speed
- Good heat resistance
- Low degree of blocking
- High thickening response
Recipe for Success
Select the Right PVOH Grade to Get the Most Benefit from Your Final Product
Before choosing any of the Selvol™ Polyvinyl Alcohol grades, you must consider the composition of the emulsion to be produced, polymerization conditions and the desire properties of the final product.
PVOH molecular weight and hydrolysis levels have a large influence on the final properties of the emulsion. In general, higher molecular weight PVOH grades will result in emulsion polymers with higher viscosity, increased shear thinning, higher tensile strength and higher wet tack. Lower hydrolysis levels will create good stability, increased water sensitivity and improved freeze – thaw stability.
Hints 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 be properly dissolved. For complete dissolution of PVOH please see our Selvol™ Polyvinyl Alcohol Solution Preparation guide (Solution Preparation)
- When using different PVOH grades, make sure the correct ratio is being used. Differences in the amounts of high or low molecular weight grades can influence emulsion viscosity.
- The use of high hydrolysis grades of PVOH results in emulsions with larger particle sizes and lower viscosities than emulsions produced using partially hydrolyzed grades of PVOH.
- 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 improved versions of standard grades specifically formulated for emulsion use with benefits including: improved cold water solubility, low foaming, reduced gel content and reduced dusting.