DOWSIL™ 67 Additive

Dow introduces a family of superwetter additives for high-performance water-based and UV-cured inks, coatings and overprint varnishes:

• DOWSIL™ 67 Additive
• DOWSIL™ 500W Additive
• DOWSIL™ 501W Additive
• DOWSIL™ 502W Additive

Do you have difficulty achieving effective substrate wetting with your waterborne or UV cured formulations, particularly on challenging substrates like wood, plastic and metal? Have you tried other silicone additives, only to see undesirable effects on slip properties?

With its range of functionalities and hydrophilicities, the new family of superwetter additives from Dow can be used in waterborne, solventborne and solventless radiation curable coatings. These additives can help you obtain the wetting performance you want for your formulation and substrate – and do so with little or no impact on slip properties.

Making an informed choice of superwetter

Dow understands that every formulation is different. By providing more information about structure, end capping and hydrophilicity/HLB, Dow seeks to improve the quality of wetting additive choices. All four products in this DOWSIL™ Superwetter family are 100% silicone polyether copolymers and are characterized by being usable in both waterborne and UV coatings formulations, offering recoatability and a high level of consistency across different types of binders.

In addition:

Performance with regulatory compliance

One hundred percent silicone polyether copolymers and solvent free technology mean no contribution to VOC when using these additives. DOWSIL™ 67 Additive is listed in the Swiss ordinance RS 817.023.21.

High performance at low use levels

DOWSIL™ 67 Additive, DOWSIL™ 500W Additive, DOWSIL™ 501W Additive and DOWSIL™ 502W Additive provide excellent wetting performance at low addition levels with little or no influence on slip. In a waterborne PUD-based flooring coating, for example, all four additives provide excellent wetting performance versus competitive organic and silicone wetting additives over different substrates. The toolbox approach also enables formulators to choose the right product for a specific application, while at the same time reducing the number of products they must maintain in their raw material portfolios. The superior performance can be measured in multiple waterborne coatings by the surface appearance and coefficient of friction (Figures 1 and 2).

Figure 1: Surface appearance and slip properties of a waterborne, PUD-based wood coating with the addition of DOWSIL™ 67 Additive, DOWSIL™ 500W Additive, DOWSIL™ 501W Additive and DOWSIL™ 502W Additive. Additives were added at 0.2 weight percent in the total formulation.

Figure 2: Surface appearance and slip properties of a waterborne, acrylic-based wood coating with the addition of DOWSIL™ 67 Additive, DOWSIL™ 500W Additive, DOWSIL™ 501W Additive and DOWSIL™ 502W Additive. Additives were added at 0.2 weight percent in the total formulation.

Figure 3: Improved wetting performance in a waterborne PUD coating with DOWSIL™ 67 Additive.

Multiple options for foam control

Because wetting agents are surfactants, they promote foam generation to some extent. The chemistry of the surfactant and the total formulation dictate the level of foam generated. Important to the formulator is that this foam can be controlled using foam control additives. Dow offers a range of antifoam additives to control any foam generated when using this new family of wetting agents.

Figure 4: Example of performance of DOWSIL™ antifoams when formulated with surfactants: DOWSIL™ 67 Additive is added at 0.4 weight percent into a flexographic gravure ink formulation. Antifoams were added at just 0.1 weight percent in the total formulation. Foam height is measured after high-speed shearing and is clearly vastly reduced with the addition of both DOWSIL™ 62 Additive and DOWSIL™ 65 Additive*.