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Driving Adhesion, Durability, and Cure Performance in Direct-to-Metal Coatings

Released By Borchers: A Milliken Brand

Additives for Polyaspartics, Alkyds & More

Direct-to-metal (DTM) coatings face demanding expectations: they must deliver strong adhesion, corrosion protection, fast dry times, ideal application, and long-term durability. Formulators rely on carefully designed additives to meet these challenges, ensuring that coatings perform consistently in real-world environments.

Borchers’ additives address these critical performance levers across a wide range of resin systems. Below are performance highlights in polyaspartic, polyurethane, and alkyd DTM coatings, as well as additional additive recommendations for other resin formulations.

Polyaspartic Coatings

Achieving full substrate wetting and adhesion

Polyaspartic coatings cure quickly, which can limit how well they wet out the substrate. When wetting is incomplete, adhesion suffers. Borchi® Gol LA 50 polyether modified polysiloxane additive for substrate wetting helps solve this challenge in waterborne, solventborne, and low-VOC systems by giving the coating more time and ability to spread evenly across the metal surface.

In fast curing polyaspartic systems, its ability to lower surface tension is essential for achieving complete surface coverage before the coating begins to cure.

When tested in a ready-to-use polyaspartic coating, Borchi® Gol LA 50 enhanced adhesion at a 2% dosage with minimal influence on pot life.

Borchi® Gen HE is an adhesion promoter that strengthens the interaction between the cured coating and the metal surface by providing anchor groups that have an affinity for metal, thereby enhancing interfacial bonding. This additive also had minimal influence on pot life when post-added in a ready-to-use coating.

Polyurethane Coatings

Tin-free catalysts for optimal dry times and durability

Polyurethane DTM coatings are prized for durability and chemical resistance but are sensitive to moisture and traditional tin catalysts. Borchi® Kat 2115 is a next generation tin-free catalyst designed for 1K and 2K polyurethane systems. It provides a strong balance of cure speed and application workability, which is essential for DTM metal coatings that need fast dry without sacrificing final film performance.

Borchi® Kat 2115 is based on a neodecanoate mixed metal technology that can replace DBTDL, DOTL, and many amine-based catalysts. It also offers improved labeling compared to traditional bismuth octoates since it is designed to be free of 2-ethylhexanoic acids.

A valuable advantage of Borchi® Kat 2115 is its ability to deliver optimal dry times while also providing a longer pot life.


Flow and leveling agents for improved substrate wetting over contaminated substrates

Borchi® Gol 1570 is a modified polydimethylsiloxane substrate wetting agent for improved flow and leveling properties in coatings systems. This VOC-free additive can deliver efficient substrate wetting in both solventborne and waterborne systems.

By lowering surface tension, Borchi® Gol 1570 helps the coating break through surface contaminants and irregularities so it can form an even, defect free film. This is especially important in DTM applications where surface preparation environments may not always be ideal and where uniform film formation is essential for adhesion and long-term durability.


Moisture scavengers to prevent moisture-related defects

High-performance moisture scavengers like Additive TITM and Additive OF minimize moisture-related defects in solventborne and solvent-free polyurethane coatings.

Additive TITM is a fast-acting moisture scavenger for short-term dehydration. It reacts quickly with residual water to prevent COâ‚‚ formation and surface defects in 1K moisture-curing and 2K polyurethane coatings. Additive TITM is colorless, low-viscosity, and can be added during production to the isocyanate portion without impacting color or clarity in final coating performance.

Additive OF is a long-term moisture scavenger that stabilizes polyurethane packages over time. It chemically converts water in the system, reducing foaming, haze, and gloss issues. Additive OF can be added to both polyol and isocyanate components and provides sustainable long-term protection against moisture-related defects.


Dispersant for Co-Grinding Multiple Pigments

A common challenge in DTM coatings includes the need to disperse multiple pigments within a formulation. Individually grinding these pigments to achieve optimal color can be tedious. Using dispersants that are able to co-grind multiple pigments at once helps streamline the dispersion process and achieve better color faster.

Borchi® Gen 0311 wetting and dispersing agent is a new development from Borchers that provides stronger color, minimized flooding and floating, and improved stability in solventborne polyurethane coatings that require co-grinding.

Alkyd Coatings

Dry times, corrosion resistance, and adhesion with high-performance catalysts

Alkyd DTM coatings must dry efficiently while still delivering strong adhesion, corrosion resistance, and consistent appearance. Slow or uneven drying can delay production, increase defect risk, and compromise long-term metal protection

Borchi® OXY-Coat high-performance catalysts are popular for their durability properties in solventborne and waterborne alkyd coatings. These cobalt-free solutions accelerate dry times, improve wet adhesion, and enhance corrosion resistance in direct-to-metal applications. Borchi® OXY-Coat high-performance catalysts also reduce yellowing and enable coatings to perform reliably in adverse weather conditions, all without the regulatory challenges associated with cobalt.


Wetting and stabilization of pigments without impacting corrosion protection in waterborne coatings

Borchi® Gen 1750 is a high molecular weight, VOC-free polyurethane wetting and dispersing agent for pigment wetting and stabilization in waterborne coatings. This multi-functional dispersant works well with organic, inorganic, and carbon black pigments.

When pigments are not properly dispersed, the coating can form weak spots that allow moisture and oxygen to reach the metal surface. This leads to rust, blistering, and reduced durability. A uniform, well-dispersed pigment system is essential to creating a strong and stable barrier that protects metal over time.

Borchi® Gen 1750 ensures uniform pigment distribution in vulnerable waterborne coatings without negatively affecting corrosion protection properties.

Benefits in Other Resin Formulations

Rheology modifiers for waterborne coatings

For proper protection and aesthetics in DTM applications, ensuring that coatings can achieve the desired viscosity and stability profiles results in optimal thickness and application.

Because water has inherently low viscosity, waterborne coatings rely on rheology modifiers to ensure proper flow and sag control. Without them, uneven application and overly thin films can occur, leading to sagging, sedimentation, and stability challenges. While often selected for their significantly lower VOCs, easier cleanup, and lower odor compared to solventborne systems, waterborne formulations require careful viscosity management to deliver consistent performance.

Borchi® Gel rheology modifiers have been tested in various waterborne formulations, including those with acrylic, polyacrylic, alkyd, epoxy, and polyurethane resins.

These additives help achieve targeted low-, medium-, and high-shear viscosities, along with anti-sag performance and prevention of sedimentation and syneresis for spray, brush, and roller applications.


Defoamers for acrylic, epoxy, and other resins

Foam can form during coating production, application, or because of difficult substrates. When foaming occurs, unsightly defects can appear, causing unappealing aesthetics and compromising coating durability.

Borchers offers defoamers and deaerators under the Borchers® AF, Borchi® Burst, and Borchi® Gol product lines. These solutions are available for a wide variety of resin systems, including alkyds, polyurethanes, and acrylics in waterborne, solventborne, and solvent-free systems.

Defoamers like Borchi® Gol 0011 and Borchi® Gol E2 are especially recommended for epoxy coatings.

Borchi® Burst DFS 500 and Borchers® AF 1171 are effective options for waterborne, solventborne, and solvent-free alkyd and alkyd emulsion systems.


Compatibilizers for colorants and base paints that utilize different carriers and resins

Universal colorants are typically used in general industrial DTM coatings. However, the carrier (e.g., water or solvent) and the resin (e.g., alkyd, polyurethane, or acrylic) of a colorant may differ from the base paint with which it is formulated. This can result in poor color development due to incompatibility. Post-addition additives like Borchi® Add compatibilizers help improve compatibility between different colorants and bases for maximized color performance and appearance.  


Consistent pigment dispersion and maintained corrosion protection in waterborne acrylic coatings

Acrylic DTM coatings may struggle with uneven wetting and pigment distribution, particularly on rough or contaminated metal surfaces. Incomplete wetting or poor dispersion can lead to surface defects and reduced corrosion protection.

For improved pigment dispersion and long-term performance, Borchi® Gen WNS low molecular weight dispersant supports efficient organic pigment wetting (potentially at a lower DOP than high molecular weight alternatives), while Borchi® Gen 1750 multi-functional dispersant helps maintain uniform pigment distribution and supports corrosion-resistant film integrity in waterborne coatings.


Additives That Drive DTM Success in a Wide Range of Resin Formulations

Across various resin systems, Borchers additives address critical challenges of direct-to-metal (DTM) formulations. By leveraging these solutions, formulators can produce coatings that are not only high performing but also reliable, durable, and easier to apply.

Order samples and download data sheets  to discover how Borchers additives for DTM coatings can enhance your formulations with the above listed resins and others.

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