Processing Tips Regulatory Compounding Tips


Compounding Tips

Millad® 3988 can be melt compounded using the standard methods currently used for other clarifying agents. Although it melts at higher temperatures than DBS or MDBS, it is designed for rapid solubilization during melt compounding. Complete solubilization is necessary to achieve the highest clarity and quality.

Compounding guidelines

Preparation of Powder Masterbatch
Thorough dispersion of Millad® 3988 in the powder masterbatch is the single most important factor in compounding high quality resins which contain this clarifier. The additive should be blended with the PP fluff or flake and other co-additives using a mechanically agitated blender until a homogeneous dispersion is obtained. Generally, higher intensity mixing is preferable.

Melt Compounding
Powder masterbatch containing Millad® 3988 should be metered into the compounding extruder along with the PP base resin at the appropriate rates. The clarifier dissolves rapidly in the PP melt; therefore, typical melt compounding temperature can be used. Filtration of the melt through a 325 mesh filter is recommended to maximize homogeneity and to remove possible traces of undispersed clarifier.

Factors Affecting clarifier dispersion
Observation of white specks in Millad® 3988 clarified PP may indicate poor dispersion of the additive.

The following table lists factors which can affect the dispersion of the clarifier in PP resin.

Observed Effect

Corrective Actions

Agglomerates in Powder Masterbatch

- Use high shear mixing.
- Decrease fluff temperature to avoid melting waxy co-additives (generally bellow 50°C (120°F).
- Screen powder master batch to remove agglomerates.
- Limit exposure to moisture to minimize hydrolysis of secondary antioxidant.

Lower Rate of Dispersion in PP Homopolymer

- Eliminate agglomerates in powder master batch.
- Use a polar dispersant such as fatty acid ester
- Increase the shear stress in the compounding extruder

Poor Melt Filtration

- Change filter screen more often to avoid holes and excessive bypass
- Use a finer filter screen (400 mesh) if possible.

 
If you have additional questions, contact us .