Pipe fittings being sprayed in a coating workshop
The foam in thick-film polyurethane coatings often comes not from stirring: dip coating and curtain coating carry air into the film, the thick film then makes the foam hard to escape, pinholes are left after curing, and the protection and the appearance of the film suffer together.
Chemi Tech supplies defoamers for polyurethane coatings and dip and curtain coating baking systems, drawn from the defoamer KMT-4053 series; this grade is benchmarked against Elementis DeuChem Defom 5300, matching the imported grade in thick-film foam removal while offering steadier supply and response. KMT-4053 is of the modified polysiloxane type, fast at foam breaking, strong at foam suppression and well compatible, and removes the foam in thick-film polyurethane markedly. Chemi Tech runs defoaming comparisons around film thickness and application method, and matches the fitted model for the customer.
Advantages of Chemi Tech Defoamers
Chemi Tech defoamer KMT-4053 series breaks foam fast and suppresses it well, and the foam in the thick film is continuously removed; at the same time it is well compatible, does not separate out and does not cause craters, so the appearance of the film is not disturbed; in addition it has no effect on the film formation and adhesion of thick-film coatings, and the protective performance stays stable; and compared with imported grades, KMT-4053 offers steady supply and a faster response, and can serve as a substitute.
Industry Pain Points and Solutions
The foam in thick-film polyurethane mostly comes not from stirring, but from dip coating and curtain coating carrying air into the film, the thick film then making the foam hard to escape; the consequence is pinholes and lingering foam, and a fall in the protection of the film.
The first problem lies in the foam lingering in the thick film. The thicker the film, the harder the foam is to escape by itself, and pinholes are left after curing. Chemi Tech's answer is to add the fast-breaking, well-suppressing KMT-4053 at the paint-adjustment stage, so that the agent is already dispersed before the coating step.
The next difficulty lies in the air entrainment of curtain coating. As the curtain falls, air is carried into the coating, and the micro-foam lingers inside the thick film. KMT-4053 from Chemi Tech is well compatible, and the foam in curtain coating is continuously removed.
What follows is insufficient compatibility. Some defoamers are not sufficiently compatible with polyurethane systems, and after breaking the foam they separate out and cause craters, damaging the appearance of the film. Chemi Tech checks the compatibility of KMT-4053 against thick-film systems, and grades the dosage by film thickness, so that the appearance of the film is not disturbed.
Typical Operating Conditions and Verification
Customer: an anticorrosive coatings manufacturer in Shandong, for the dip and curtain coating of thick-film polyurethane coatings.
At this plant the thick-film polyurethane coating came out with rather too many pinholes after curing, and the foam lingered noticeably; imported grades had been used before without holding steady either. The solution Chemi Tech defoamer gave for the situation was: taking film thickness and application method into account, choose the KMT-4053 series, move the point of addition to the paint-adjustment stage, re-calibrate the dosage by film thickness, and use it as an import substitute. After the solution was switched in, pinholes in the film fell noticeably, the lingering foam was largely cleared, and the protection and the appearance returned to the normal range.
Frequently Asked Questions
If imported grades are currently in use, can Chemi Tech run a comparison first and then give a substitute dosage?
Yes. Chemi Tech can run a dedicated comparison against your film thickness and application method, check the thick-film defoaming performance item by item against the imported grade, and then give the substitute dosage and the point of addition. The exact dosage is decided by film thickness and application method, and Chemi Tech gives the substitute plan after the dedicated comparison.