The ink rollers and inking system of a printing press
Raise the matting agent loading in a UV matte coating and the viscosity of the system rises with it: the coating roller struggles to form an even wet film, gloss on the panel comes out mottled and uneven, and the lower the gloss target, the harder the formulation is to tune, with most rejects traceable to insufficient dispersion of the matting agent.
Chemi Tech supplies dispersants made for radiation curing systems such as UV inks, UV industrial coatings and plastic coatings, represented by the KMK-4009 series. The specific formulation has to be adjusted against the type of matting agent, the target gloss and the solids content of the system. KMK-4009 is a polymeric product with an outstanding viscosity reduction effect on matting agents: it lifts the matting agent loading markedly and coats it stably in solvent-free and radiation curing systems. Chemi Tech can assess against the matting agent category and the target gloss and match a dispersant grade for the customer.
Advantages of Chemi Tech Dispersants
Chemi Tech dispersant KMK-4009 series is a polymeric product with stable coating of the matting agent: after grinding there is no agglomeration and no coarsening back. The viscosity reduction is outstanding as well — at the same matting agent loading the system viscosity is markedly lower and roller coating lays down an even film. Matting agent carrying capacity is higher, so a low gloss formulation does not need multiple coating passes: one application meets the target. Storage stability is excellent, with the matting agent unlikely to settle and cake, and no long stirring on opening; gloss uniformity is good as well, with the panel even and the matte effect consistent.
Industry Pain Points and Solutions
Uneven gloss in a matte coating is mostly rooted in matting agent dispersion. The most grinding part is gloss fluctuating across samples from the same batch — under the customer's inspection lamp there is nowhere for the defect to hide.
The first difficulty: raise the matting agent loading and the system thickens quickly. Matting agents have a high oil absorption value, so a larger dose pushes the viscosity up and the coating head struggles to form an even film. Chemi Tech verifies viscosity reduction first, assessing viscosity control at the same loading.
Next is the matting agent settling. In a thinner system the matting agent tends to sink and cake at the bottom of the drum, so the gloss of the top and the bottom differ widely. Chemi Tech assesses dispersion and anti-settling together, keeping the powder in stable suspension so gloss is consistent from opening the drum to using it up.
The last category of pain point: a low gloss formulation scraped through by a second coating pass. With the matting agent loading limited, the only option is two thin coats, which doubles the labour hours and tends to leave lap marks. Chemi Tech's approach is to run a loading trial around the target gloss, raise the effective matting agent loading, and get there in one coating pass.
Typical Conditions and Verification
Customer: a UV coatings enterprise in Zhejiang, applying it to the UV matte topcoat line for plastic substrates.
The plastic coating at this plant had a demanding matte specification, and once the matting agent loading was raised the system viscosity shot up, coating came out uneven, gloss on the panel was mottled, and the customer raised objections at acceptance repeatedly. Chemi Tech dispersant gave a targeted solution: against the matting agent type and the target gloss, grade KMK-4008 was selected, raising the matting agent loading while effectively lowering the system viscosity. After switching to this approach, one coating pass gives even gloss and the reject rate has come down with it.
Frequently Asked Questions
Raising the matting agent loading, will that pull adhesion down?
Not necessarily, but it must be validated: once the pigment and filler ratio changes, the mechanical performance of the film changes with it. The KMK-4009 Chemi Tech supplies to UV coating plants has been compared for adhesion and gloss at different loadings, and it is recommended only when the data falls inside the window. Chemi Tech will settle the match on the basis of your formulation data.