Corrugated steel sheet with blue coating
Solvent-based coil coatings go into baking after high-speed roller coating; if the levelling agent is not compatible enough with the system, the clear coat hazes with it and the pigmented coat surface shows haze shadows, the panel clarity and gloss fall, and the appearance consistency of the coil after it comes off the line suffers.
Chemi Tech supplies levelling agents for solvent-based coil and higher-appearance coating systems, drawn from the levelling agent KMP-4605 series; the dosage is set by the coating system, the roller coating line speed and the baking conditions. Chemi Tech compares levelling performance against the coating system and the roller coating line speed, and fixes the fitted dosage range for the customer.
Advantages of Chemi Tech Levelling Agents
Chemi Tech levelling agent KMP-4605 series is highly compatible, does not cloud the clear coat once added, and keeps the panel clear; moreover, it shows no haze shadows in pigmented coats and gives even, uniform gloss; at the same time, it does not disturb intercoat adhesion, and the bond in coil recoating and downstream processing stays stable; in addition, its polyacrylate-type structure matches solvent-based systems, and it can be added to both clear and pigmented coats.
Industry Pain Points and Solutions
Haze shadows in solvent-based coil coatings usually stem from the levelling agent's compatibility with the system rather than from the roller coating pressure; the consequence is a hazed clear coat and falling panel gloss.
The most troublesome is the hazing of the clear coat. The levelling agent clouds out of the clear coat, the film clarity falls, and the panel appearance suffers. Chemi Tech chooses the KMP-4605 levelling agent, which does not cloud in the clear coat, added at the mixing stage, so that the film finishes spreading before surface drying and stays clear.
The most common is the haze shadow on the pigmented coat surface. When the levelling agent is not compatible enough with the pigmented coat, haze shadows separate out on the surface and the gloss goes uneven. Chemi Tech's KMP-4605 levelling agent eliminates haze shadows when used in pigmented coats.
The core difficulty lies in maintaining intercoat adhesion. After the coil comes off the line it must go through winding, forming and several downstream processing steps; if the levelling agent concentrates heavily on the film surface, it directly weakens the intercoat bond. Chemi Tech runs levelling-performance benchmark screening against the coating system and chooses the KMP-4605 levelling agent, which has no negative effect on adhesion, suited to the high-speed roller coating production, and can keep both the panel clarity and stable intercoat adhesion.
Typical Operating Conditions and Verification
Customer: a coil coating manufacturer in Shandong, for the roller coating and curing stages of solvent-based coil.
At this plant the panel hazed after roller coating of the clear coat and the pigmented coat showed haze shadows, with gloss dropping, and poor adhesion appeared in the downstream forming process. Taking the coating system and the roller coating line speed into account, Chemi Tech chose the KMP-4605 series levelling agent and re-fixed the dosage and the feeding point by the baking conditions. After the approach was implemented, the clear coat clarity recovered, the haze shadows in the pigmented coat cleared, and the panel gloss and intercoat adhesion both came back to qualified figures.
Frequently Asked Questions
For a levelling agent in solvent-based coil, what should be watched when the dosage runs high?
When a levelling agent is used in solvent-based coil coatings, the primary risk of an over-high dosage is that the levelling agent concentrates on the film surface and tends to cause clear-coat hazing and falling intercoat adhesion. For this case, Chemi Tech KMP-4605 levelling agent has completed comparison tests of film clarity and adhesion under multiple dosage gradients, and recommends only the dosage range in which both properties stay stable. The upper dosage limit must be fixed together with the roller coating line speed and the baking conditions, and Chemi Tech can give a recommended value from the on-site baking curve.