Millad® clarifying agents make polypropylene even more appealing through a variety of innovative benefits.
Features of using Millad Clarified Polypropylene
- Revolutionary clarity
- Improved aesthetic appeal
- Flexible and simple processing
- Productivity enhancement
- Light weight
- Cost effective
- Good stiffness/impact balance
- Environmental sensitivity
- Chemical and thermal resistance
- Good moisture vapor barrier
- Hot fill and retort capability
How it works
Polypropylene Crystallization and Haze
Polypropylene is a semi-crystalline polymer. The presence of this crystalline structure enhances the stiffness, as well as the mechanical, chemical and thermal resistance of the material. Polypropylene normally crystallizes slowly and forms relatively large complex crystal aggregates known as spherulites. The growth of these spherulites is generally initiated around microscopic "sites" naturally present in the material. This phenomenon is called nucleation.
Without clarifier, the size of these spherulites is generally larger than the wavelength of visible light resulting in light scattering and hazing of the material.
Nucleation and Clarification
Adding a clarifier to polypropylene is equivalent to introducing "additional sites" in which spherulites can initiate their growth. When polypropylene is clarified with Millad, the rate of crystal initiation is increased by orders of magnitude throughout the polymer. Because many more crystals are growing in the same amount of space, they are all much smaller in size. The result is crystals smaller than the wavelength of visible light that allow light to pass through, imparting enhanced clarity. The figure below illustrates this process.