Have you ever wondered how so many different colors can be added to the same paint – or even across different paint systems – while still maintaining the high performance required of the coating?
Probably not top of mind…but it should be!
Color development is more than just aesthetics – it is a critical formulation challenge. Consider this:
- Pigments are one of the most expensive components in a paint system
- Formulators need versatile, robust systems that reduce complexity – not increase it
- Not all pigments behave the same, making consistent, high-performance color development difficult
Delivering strong, consistent color across systems is not easy – but that’s exactly where BASF’s Laropal chemistry and Efka® dispersants come into play. And while color is a big part of the story, it is only the beginning. Stay with us as we explore even more of what Laropal can do.
What Is Laropal Chemistry?
Key products, Laropal A 81 and Laropal A 101, are condensed urea-aldehyde polymers with high glass transition temperatures (Tg) that are delivered in solid pellet form. This delivery form allows the formulator to work with their own desired solvent packages and levels within their systems.
The difference between the two products lies in the softening point of the solid – Laropal A 81 softens at 81°C, while Laropal A 101 softens at 101°C.
The value of this polymer backbone technology lies in the chemistry. Laropal resins offer:
- Strong pigment affinity for effective dispersion
- Balanced performance properties
- Broad compatibility across coating systems, including epoxies, polyurethanes, alkyds, nitrocellulose, melamines, acrylics, and more
This broad compatibility gives formulators a more flexible approach to color development. Rather than being restricted to a single technology, they can use Laropal as a pigment grinding resin during the color development stage and then incorporate the finished colorant into a wide range of coating systems.
In other words, the dispersion can be developed once and used across multiple formulations – simplifying the process while maintaining performance, something more conventional systems often struggle to achieve.
Image 1: Laropal A81 based pigment dispersions can be made, combined and added into multiple systems reducing complexity (right), whereas non-Laropal based dispersions need to be made specific for end chemistry, so multiple chemistries of the same color need to be manufactured (left)
The added benefit of the Laropal chemistry in color development is highlighted in the image below, where a Phthalocyanine blue colorant is developed using an acrylic grinding resin, Laropal A81, and an alkyd resin. This colorant is then incorporated into a white alkyd-melamine baking enamel system.
The color strength is clearly more pronounced in the Laropal A81-containing sample – meaning less pigment is required to achieve the same level of performance (remember the cost of pigments?!).
Image 2: Stronger color development with Laropal A81 means less pigment is needed, helping reduce formulation costs. Comparison in image between acrylic dispersion resin, Laropal A81, and an alkyd resin.
New Laropal Solutions: Ready When You Are
To make formulation easier, new grades of Laropal A 81 are pre-cut into different solvents in case formulators cannot cut their own resins. The three grades are cut in either Naphtha, Xylenes, or methoxypropyl acetate which offer broad polarity ranges and evaporation rates.
Laropal 855 S – Naphtha based, 55% solids
Laropal 860 X – Xylenes, 60% solids
Laropal 863 M – Methoxypropyl acetate, 63% solids
For maximum efficiency, these systems are promoted to be combined with more universal high performance pigment dispersants for maximum efficiency such as:
Efka PX 4330 – CFRP dispersant for broad usage across organic and inorganic pigment types
Efka PX 4753 – CFRP dispersant with excellent dispersibility of phthalo-based pigments, carbon blacks, and inorganics
Beyond solvent-borne systems, Laropal LR 9008 brings the same value proposition to waterborne systems. As a modified version of Laropal A 81 pre-dispersed in water, it delivers the compatibility and pigment efficiency formulators expect – now in waterborne coating systems. Key benefits include:
- Strong compatibility and pigment efficiency in waterborne coating systems
- Addresses common challenges in pigment preparations that are prone to crusting or dry-out when exposed to air
- Enables consistently wetted systems, minimizing issues such as flaking
Performance Beyond Color
Laropal A 81 and Laropal A 101 are effective solids for flow aids in powder coatings applications due to their softening point.
Laropal A 81 has also been proven to be compatible in 100% solids UV-curable systems, where it can support reactivity modification and boost overall performance – maintaining 100% solids content while assisting in pigment grinding and providing a tool to adjust crosslink density without compromising hardness.
One key advantage of Laropal A 81 is its functionality as a reactive co-binder, driven by the hydroxyl groups along its backbone. With a hydroxyl value of approximately 20 mg KOH/g, it enables low isocyanate demand while creating a tighter network between resins and pigments in the system.
Specifically in polyurethane systems, this can be advantageous. In a solvent-borne 2K PU application, Laropal A 81 was incorporated as a co-binder during the pigment dispersion step, resulting in:
- Improved flexibility at the same hardness level
- Enhanced weatherability (especially in combination with Tinuvin® UVA absorbers and HALS light stabilizers)
- Very high MEK double rub resistance
- Slightly reduced VOC and higher tinting strength compared to a non-Laropal styrene-acrylic polyol control.
The Laropal backbone also provides excellent weatherability and resists yellowing under UV exposure – an important advantage over many alternative technologies.
Image 3: 2K white PU formulation without Laropal shows cracking at high mandrel bending, whereas Laropal A81 containing formulation provides more robust balance of flexibility while maintaining hardness.
Let’s Build Better Color – Together
Whether you’re optimizing existing formulations or exploring new systems, Laropal chemistry offers the flexibility and performance to move faster and go further.
Laropal continues to deliver – now available in presolubilized forms and finding homes in new application spaces.
Ready to simplify your color strategy and improve performance?
Connect with us to learn how Laropal and our Efka dispersants can support your next formulation.