A third-generation beta nucleating agent developed by Mayzo (Suwanee, GA) is under evaluation by several automotive suppliers as a way to enhance the impact strength of thermoplastic olefin (TPO) elastomer with minimal loss of stiffness.
“It offers another mechanism for impact enhancement. There’s a combination of benefits, such as lightweighting and reducing some of the elastomeric components of the compound,” said Philip Jacoby, vice president of technology at Mayzo in an interview with The Molding Blog. Loading would be about 2% for compounds with talc and 1% or less for compounds without talc.
The third-generation beta nucleating agent invented by Jacoby about 18 months ago can work in the presence of alpha nucleants such as sodium benzoate and some pigments. That’s a major change from previously available technology.
The purpose of nucleating agents in polypropylene is to increase its crystallinity. It does this by increasing the concentration of nuclei so that crystallization starts faster and reaches a more complete state before the part has cooled to too low a temperature for additional crystals to develop. Beta nucleants, which are less common than alpha nucleants, provide enhanced ductility.
Beta nucleants are also beneficial in other process such as thermoforming and film processing.
Benefits for thermoforming include:
- Broader processing window,
- Better material distribution,
- Lighter weight, and
- Lower density (microvoiding).
The third-generation beta nucleating agent is being made in-situ, a different approach that increases surface area. “The more surface area you have in contact with the polymer, the more active the agent is,” Jacoby said. The general practice is to buy nucleating agents and add them to the polypropylene. Jacoby’s approach also reduces cost by starting with lower cost chemicals.
Mayzo’s primary business is primarily off-patent additives using chemicals often sourced offshore. Masterbatches are produced under tolling arrangements.