Coloring Systems

Additives Technology and Cost Reduction Methods in Coloring Systems

Summary

Ever changing environmental regulations, pressure for cost reductions and increasing demand for superior performance are key drivers for developments in the coating industry. Business success is linked with reaction speed to market developments, such as implementation of new binder systems or more recently, alternatives, due to scarcity of raw materials.

Manufacturing flexibility is achieved making use of in-plant tinting. Tinters -formulated using the Patcham dispersant additive technology- are part of this process. High demands are put on batch-tobatch uniformity and long-term stability.

This paper contributes to sharing information on the formulation of In-plant tinters, designed for tinting purposes of non-aqueous industrial paints. The tinter formulation concept allows the use of a wide variety of binders, pigments, and solvents: aromatic
or aromatic free.

Introduction

Demand for VOC reduction and restrictions for use of solvents or binders due to regulatory (or more recently, for reasons of availability) force the paint formulator to adjust formulations, with no room left for increasing formulation costs.

Quite challenging, not only in relation to immediate differences in raw materials costs, but also to manufacturing issues-such in case of low VOC, low aromatic formulations-higher mill-base viscosity, limited binder solubility, poor wetting characteristics of aromatic free solvents and stability conditions.

Corrections are necessary, offered by additives to be used in the ready-made paint formula; or alternatively changing the coloration system by accepting the use of a tinting system with pigment concentrates or tinters.

Dispersing agent Pat-Add DA 3054 is successfully used to formulate concentrated tinters up to low VOC paints and to formulate pigment dispersions for general industrial, automotive as well as protective coatings.

A major breakthrough in the coloration process as used now, has been the introduction of for this purpose well designed polymeric dispersing agents, which allow formulation of high-loaded pigment concentrates, to be used for in-plant tinting systems of nearly any kind of paint.

Pigment Dispersions and Additives

Pigment concentrates are made starting from polymeric dispersant, dissolved in a compatible solvent system and eventually in combination with a multicompatible resin. Pigments are dispersed and stabilized in this medium and dosed into the transparent
or pigment base paint, applying gravimetrical or volumetric dosage.

A prime condition for successful use is providing robust pigment flocculation stability, at any rate of addition of the pigment concentrate to the paint system. Said conditions are met using High Molar Volume -HMV- dispersant technology (example: PatAdd DA 3054). The adsorbed dispersant molecules provide a protective layer, thus preventing reflocculation of pigment particles.

High adsorptive layer volume means formation of a more robust stabilization layer, approx. 25% higher thickness as to classical polymers. Higher volume, contributing to improved dispersion stability, lowering risk of re-flocculation!

Main Benefits of Pat-Add DA 3054

• Provides robust pigment dispersion stability, minimizing risk of pigment flocculation.
• Applicable for co-grinding milling procedures as well as for pigment concentrates.
• Provides excellent spray dilution stability, minimizing risk of paint separation.
• Prevents pigment floatation.
• Optimizes film appearance properties like DOI, gloss, transparency.
• Free of aromatic solvents.
• HAPs Free.

References
1; J H Bieleman, “Additives for Coatings”, publ. Wiley-WCH, 2000
2: Patcham literature, www.patchamltd.com

Bahar Aydın
Technical Sales & Product Manager
Nordmann