The rolls and frame interior of a large calendering unit, no people in frame
Put more titanium dioxide into an epoxy primer and the grind fineness jams at the threshold, the anti-settling paste coarsens once it goes in, the shade differs top to bottom in the tank, and the sprayed panel falls a breath short on hiding power, with the cost booked against the grinding step.
Chemi Tech makes polymeric dispersants for epoxy primers, industrial protective coatings and coil coating systems, in the dispersant KMK-133 series. Which grade is added depends on the pigment type, the surface treatment process and the target pigment content. For inorganic pigments such as titanium dioxide, KMK-133 is built in this group in the direction of viscosity reduction with pigment content pushed up; in solvent-borne systems, or where transparency and hiding power are held to a higher standard, the wetting dispersant KMT-4130 is the closer fit and is widely used in acid-catalysed coil coatings. Send over the formulation backbone of the pigmented coat and the target content, and these items will be gone through by us before an answer is given, which also saves you working through the grades one at a time.
Advantages of Chemi Tech Dispersants
This grade of the Chemi Tech dispersant KMK-133 series grips the pigment surface through anchoring groups and does not desorb under high-shear grinding, which is exactly the layer where high pigment content systems most often run into trouble. The viscosity reduction is substantial as well, so at the same pigment content the millbase still flows and the bead mill current holds steady. Its adaptability across inorganic and organic pigments is broad, too, so changing pigment does not mean tearing the formulation down and starting again. The ground millbase is stable in storage: a month on the shelf brings no coarsening and no flooding, and the shade is consistent top to bottom in the tank. On top of that, the dosage runs at a small percentage of the pigment weight, so the overall cost sits a notch below imported options.
A note from Chemi Tech: the behaviour above comes from a typical epoxy primer grinding condition. Change the pigment type or the surface treatment process and the results move. Confirm on a small sample before scaling up.
Industry Pain Points and Solutions
Thickening and flooding in a primer lie mostly not in the mill but in whether the dispersant and the pigment get a grip on each other.
Changing pigment supplier without moving the formulation is the first place people run into trouble. Switch one grade to another supplier's material and the surface treatment differs; the grade in use no longer grips the new pigment, hiding power and fineness both fall, and the cost is booked against the grinding step all the same. Chemi Tech runs a round of anchoring validation on each of the pigments in use, so the formulation follows the pigment.
What surfaces next is that viscosity reduction and anti-settling are hard to have both ways. Cut the viscosity hard and the dispersion state of the pigment particles loosens with it, so the anti-settling paste coarsens the moment it goes in. Chemi Tech's approach is to put viscosity, fineness and anti-settling performance into one gradient table and take the items through together.
One more point is that the solids content of the formulation will not come up. If the dispersant does not grip, a higher pigment content pushes back, and the packaging and freight accounts do not add up. Chemi Tech's approach is to run a gradient trial against the target solids content and mark out the dosage boundary of the dispersant first.
From anchoring comparison to gradient bench work and on to the grinding parameters of the bead mill pilot, recommendations are made against your actual formulation, and the test data is filed for you with it.
Typical Conditions and Verification
Customer: an industrial protective coatings manufacturer in Guangdong, applying it to the grinding and let-down steps of an epoxy primer.
This mill wanted to raise the pigment content of its epoxy primer to cut packaging and freight, tried a round in which the fineness fell short and the anti-settling paste coarsened, and after backing off still had unstable shade between batches and occasional feedback that the sprayed panel lacked hiding power. The solution offered by Chemi Tech dispersants was: against the surface treatment of the titanium dioxide and the system resin, KMK-133 was selected from the KMK-133 series, a blank comparison was run first to confirm the trouble sat in the anchoring layer, and then a bead mill pilot was run. After the change the pigment content moved up a band, grinding fineness and anti-settling performance both met specification, single-tank capacity came up, and a retained sample showed no fineness or shade drift after a month. Quality control reported that production output was steady.
Frequently Asked Questions
When the titanium dioxide grade is changed, must the dispersant be changed with it?
Not necessarily, but it must be validated: once the pigment surface treatment changes, a dispersant that used to grip may no longer grip, and both fineness and hiding power are affected. The KMK-133 Chemi Tech supplies to coatings mills is compared on a per-pigment anchoring basis, and which grade is used is settled by us after looking at the data. Give the pigment grade, the surface treatment method and the target solids content to the Chemi Tech technical engineers, and a round of anchoring comparison and gradient data will be run for you, with the conclusions passed to the workshop together once they are out.