High-solids polyurethane (PU) inks often generate persistent foam during grinding due to high viscosity and slow solvent release, leading to microfoam residues and coating defects. Chemi Tech's defoamer KM-808, designed for PU systems, utilizes an organosilicone-acrylate composite structure to rapidly rupture foam films without causing craters from compatibility issues.
Technical Mechanism
KM-808's molecular design focuses on dynamic surface tension control:
Grinding-Stage Suppression: Low-polarity groups adsorb at bubble interfaces, reducing film strength and increasing burst speed by 50%.
Microfoam Elimination: Nanoscale hydrophobic particles penetrate foam lamellae, accelerating gas diffusion.
Process Stability: Stable under three-roll mill temperatures (≤80°C) without oil separation.
Case Study: Screen Ink Production
An ink manufacturer producing 70% solids PU screen inks faced 30% foam volume during grinding, causing pigment agglomeration and print voids. After adding 0.4% KM-808:
Foam Control: Foam volume reduced to 5%, defoaming time cut from 120 to 40 minutes.
Print Quality: Dot clarity improved; no plate clogging after 10,000 impressions.
Stability: Ink viscosity remained stable after 30-day storage at 50°C.
This solution reduced annual waste by 12%. Chemi Tech offers customized dosing protocols for various grinding equipment.