Checking print adhesion after zinc stearate improves mold release

Does ash content measure zinc directly?

A molded part can release more readily yet lose print adhesion. Inspecting only the molding station would miss the downstream effect.

Track print adhesion after molding

Compare parts from the same shot and position using identical surface treatment and ink. Record release and adhesion together. For active zinc calculations, verify the assay; ash is not a direct measure of zinc.

What if release improves but print adhesion worsens?

Check surface migration, dosage and subsequent surface treatment. Plastics mold release: Using the same mold, compare release, surface residue and adhesion of subsequent coatings. Polymer powder blending: Record dispersion, feed flow and exudation after processing.

Checking Zinc content and Free fatty acids

Zinc content (% by mass): Specify whether the result is expressed as Zn or ZnO equivalent. Free fatty acids (% by mass): Request the method and specification. Particle size (µm): State D50 and the coarse end of the distribution. Check for agglomeration.

What to record

• Addition rate
• Molding position
• Release condition
• Printing conditions
• Adhesion performance

Technical references

• Baerlocher: zinc stearate and polymer processing applications ↗

Products and processes