A ship hull awaiting repair in a dry dock
When a heavy-duty anti-corrosion coating is sprayed it entrains air bubbles, and the thick film makes them hard to escape, so pinholes and bubbles are left behind once it cures, the barrier protection the film gives the steel structure falls with it, and the service life of the coating and the acceptance rate suffer.
Chemi Tech supplies defoamers for anti-corrosion and marine coating systems, drawn from the defoamer KMT-452 series; this one is benchmarked against BYK-052, speeds up defoaming in solvent-based systems, defoams quickly in solvent-free systems, and is more stable in supply and response. KMT-452 is an acrylate polymer and does not interfere with the film formation or the adhesion of thick-film coatings. Chemi Tech compares defoaming performance around the film thickness and the method of application, and matches the fitted model for the customer.
Advantages of Chemi Tech Defoamers
Chemi Tech defoamer KMT-452 series speeds up defoaming in solvent-based systems, and the micro-foam in the thick film is cleared continuously; at the same time it defoams quickly in solvent-free systems, leaving no pinholes in heavy-duty thick coating; in addition, it does not interfere with film formation or adhesion, so the barrier protection of the film stays steady; moreover, compared with imported grades, KMT-452 is stable in supply and faster in response, and can serve as a substitute.
Industry Pain Points and Solutions
Pinholes in heavy-duty anti-corrosion coatings mostly do not come from stirring, but from the thick film making the bubbles hard to escape; the consequence is pinholes and bubbles that linger and a fall in the protection of the film.
The first problem is the lingering bubbles in the thick film. The thicker the film, the harder for the bubbles to escape on their own, and pinholes are left after curing. Chemi Tech's answer is to add the KMT-452, which speeds up defoaming in solvent-based systems, at the paint-adjustment stage, so that the agent is already dispersed before coating.
The next difficulty is defoaming in heavy solvent-free coating. In solvent-free systems the viscosity is high, the bubbles escape more slowly, and the defoamer has to break foam quickly. KMT-452 from Chemi Tech is an acrylate polymer, defoams quickly in solvent-free systems, and leaves no pinholes in thick coating.
What follows is the weakening of the protection. Pinholes and bubbles break the continuity of the film, the barrier protection falls, and the steel structure faces corrosion risk. Chemi Tech checks the compatibility of KMT-452 with the thick-film system, grades the dosage by film thickness, and the barrier protection of the film is left undisturbed.
Typical Operating Conditions and Verification
Customer: a marine coatings manufacturer in Shanghai, for the spraying and thick-coating stages of heavy-duty anti-corrosion coatings.
At this plant the heavy-duty anti-corrosion coating left rather too many pinholes after curing and the bubbles lingered noticeably; the imported grade used before did not hold it steady either. The solution Chemi Tech defoamer gave for the situation was: taking the film thickness and the method of application into account, choose the KMT-452 series, move the point of addition to the paint-adjustment stage, and re-calibrate the dosage by film thickness, as an imported-grade substitute. After the solution was switched in, the pinholes in the film fell markedly, the lingering bubbles were largely cleared, and the barrier protection returned to the normal range.
Frequently Asked Questions
If an imported grade is being used at present, can Chemi Tech run a comparison first and then give a substitute dosage?
Yes. Chemi Tech can first run a dedicated comparison according to your film thickness and method of application, check the thick-film defoaming performance against the imported grade item by item, and then give a substitute dosage and point of addition. The specific dosage is set by the film thickness and the method of construction, and Chemi Tech gives a substitute scheme after the dedicated comparison.