DOWSIL™ 500W 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:

Key features of DOWSIL™ 500W Additive

Besides excellent wetting performance at low addition levels, DOWSIL™ 500W Additive provides long lasting performance in high pH binders.

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.

Achieving excellent wetting without affecting slip properties is particularly important for wood floor coatings, and DOWSIL™ brand superwetter additives provide the necessary performance. 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: Application over oily substrates is improved with the use of any of the products in the DOWSIL™ Superwetter family tested at 0.2 wt% addition levels in waterborne flexographic gravure ink.

Stable wetting performance at high pH

The chemistry of silicone surfactants can often mean they are not stable in higher pH formulations and performance is lost during storage of the coating or ink.

DOWSIL™ 500W Additive, however, is ideally suited for higher pH formulations and shows good wetting performance initially and on longer-term storage. Other additives show high surface tension at pH 11, indicating instability. With DOWSIL™ 500W Additive, surface tension remains consistently low.

Figure 3: Stability of DOWSIL™ 500W Additive as demonstrated by dynamic surface tension stability over time in a pH 11 solution. Static surface tension remains consistent even after 1 month of storage.