Waterborne epoxy coatings must be free of fine particles before they leave the plant. Even small amounts of resin particles or gels end up as specks and craters in the applied paint film. At very low solids content, these particles are difficult to capture reliably, and conventional filters struggle to deliver consistent filtrate quality batch after batch.
Project at a glance
| Customer | Coatings producer, China |
| Application | Polishing filtration of waterborne epoxy coatings |
| Scope | One FUNDABAC® candle filter system with precoat and body feed |
| Process challenge | Removing very fine epoxy particles at very low solids content |
Why is fine particle removal difficult in waterborne epoxy coating production?
The solids in a finished waterborne epoxy coating are few, fine, and often soft. At such low concentrations, the particles alone cannot build a filter cake that retains them. Fine or gel-like particles pass through the filter medium or blind it, and filters that rely on frequent bag or cartridge changes require opening the housing between batches.
How does the FUNDABAC® candle filter handle low solids content?
In 2017, DrM supplied a FUNDABAC® candle filter system to a coatings producer in China for the polishing filtration of its waterborne epoxy coatings. The design was based on filtration tests with the customer’s product. Because the solids content is too low to form a cake on its own, the system works with filter aid. A precoat layer is first built on the filter cloths, and body feed is dosed into the product during filtration, so a permeable cake forms that captures the fine epoxy particles.
The filter, precoat tank, body feed tank, and associated pipework are mounted on a single skid. Filtration, cake discharge by gas blow-back, and heel volume filtration run in a closed vessel under PLC control, with the cycle ending automatically at a set differential pressure.
What has long-term operation shown?
In 2026, almost nine years after installation, DrM’s sales team visited the site. The customer reported stable retention of fine particles and good control of impurities. Automatic operation has kept maintenance effort on site low, and the closed process avoids the open handling associated with bag changes.
This project adds to DrM’s reference base in resin and coating production, including epoxy resin applications in China, Taiwan, Korea, and Turkey, and shows how FUNDABAC® filters with precoat and body feed handle polishing duties where the solids content is too low for direct cake filtration.
