Wooden tables and paint cans inside a workshop
The moment a wood coating goes on, the surface dries too fast: the film sets before it has levelled, the panel carries orange peel, and under light it shows even more clearly, so the batch can only be sanded back and resprayed.
Chemi Tech makes leveling agents for waterborne wood coatings, furniture coatings and industrial coatings, drawn from the leveling agent KMP-4100 series. How a grade is matched depends on the resin system, the spray method, and the drying temperature curve. KMP-4100 is a waterborne system with a marked reduction in surface tension, and it holds the dynamic surface tension down as well, so the film spreads after spraying; where intercoat adhesion has to be held, the addition level has to be calibrated against the spray cycle. Send the resin system and the spray parameters over, and we will settle the addition level and the point of addition for you and recommend the process parameters.
Advantages of Chemi Tech Leveling Agents
Chemi Tech leveling agent KMP-4100 series cuts surface tension markedly, so the film spreads before the surface dries and the orange peel on the panel moves up a grade. Compatibility is good as well: it causes no craters and does not harm intercoat adhesion, so no extra treatment is needed between the two spray passes. Its effect on gloss is small, too — clearcoat systems stay clear once it is in, and pigmented coats show no haze. Heat stability holds up as well, with no decomposition and no yellowing through the baking stage. And recoatability is left room for, so the coats hold together when a respray is needed.
A note from Chemi Tech: the behaviour above comes from a typical waterborne wood coating spray condition. Change the resin system or the baking temperature and the difference becomes clear.
Industry Pain Points and Solutions
Orange peel on wood coatings is usually not a matter of too little leveling agent; it is the leveling window being squeezed shut by the surface dry. What worries people most is rework, which burns time and material.
Looking only at the addition level and not at surface drying is the first difficulty encountered. The moment orange peel appears more leveling agent goes in, and in the end adhesion falls away and the problem gets more complicated instead. Chemi Tech measures the static and dynamic surface tension of the system together, and looks at which stretch the gap falls in.
What follows is a drying curve that has not kept pace. When the surface dries too quickly the film sets before it can spread, so the texture naturally cannot be pressed flat. Chemi Tech's approach is to verify the leveling time and the baking conditions together, rather than looking only at how much additive went in.
Another pain point is a change in the spray cycle. When the line speeds up, the gun sits closer and moves faster, the film thickness becomes uneven, and there is less room to level. Chemi Tech's approach is to run a leveling comparison against the actual spray cycle and recalibrate the addition level and the point of addition.
Typical Conditions and Verification
Customer: a wooden door manufacturer in Guangdong, applying it to the topcoat spray stage of wood coatings.
The topcoat on the doors from this plant carried heavy orange peel, the proportion needing sanding back and respraying was high, and the delivery cycle was stretched out. The solution offered by Chemi Tech leveling agent was: against the resin system and the spray parameters, KMP-4101 was selected from the KMP-4100 series, the addition level and the point of addition were recalibrated against the spray cycle, and the baking temperature curve was adjusted to suit. After the change the orange peel on the panel moved up a grade and the rework rate came down markedly. Where a batch of doors used to be sorted for a good many reworks, now they can go straight to the next process step off the line.
Frequently Asked Questions
Will too much leveling agent affect intercoat adhesion?
It will: if the surface tension is pressed too low, the two coats will not hold together on a recoat. The KMP-4100 series Chemi Tech supplies to wood coating plants has been compared against recoatability, and at normal addition levels adhesion does not fall. If there are further questions, the technical department at Chemi Tech will answer them for you at any time.