ARTICLE | BASF's Approach to Performance Without PCBTF

What’s the Hustle and Bustle About In Automotive Refinish?

The major shift in the Automotive Refinish industry stems from the removal of PCBTF (para‑chlorobenzotrifluoride) as required by South Coast Air Quality Management District (SCAQMD) Rule 1151 in Southern California. PCBTF has lost its VOC exempt status and has been designated as a carcinogen, which means it can no longer be used in refinish coatings.

To ease the transition, Rule 1151 provides a grace period until 2029. During this time, VOC limits for refinish coatings may be temporarily increased, enabling formulators to replace PCBTF with non‑exempt VOC solvents. Beginning in 2029, clear coats must once again comply with the 2.1 lb./gal VOC requirement.

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What’s the Hurdle?

Formulators face significant hurdles because viable VOC exempt alternatives are limited. Current options like acetone and methyl acetate evaporate very quickly, while others like propylene carbonate evaporate extremely slowly. This initiates the need for automotive refinish formulators to reevaluate the formulation construction to effectively balance properties.

BASF’s Formulation Approach

To effectively balance the properties of these coatings, BASF Resins and Additives have developed starting formulations based on the toolbox currently available to formulators. BASF’s Resins and Additives division is primed to deliver solutions which accelerate the adoption of formulations without using PCBTF.

Our approach is guided by three key requirements:

Comparable application behavior:

Formulations need to be applied in the same way as traditional refinish coatings, meaning viscosities of the finished systems need to be similar.

Consistent dry speeds:

Tack free times need to be similar for throughput in a body shop environment.

No compromise in appearance:

The appearance must not be sacrificed compared to commercial coatings containing PCBTF.

Basonat^® HI 3100

A newly launched polyisocyanate designed for both water-based and solvent-based systems offers exceptionally low viscosity – the lowest within our isocyanate portfolio. This allows the Part B component to remain low in viscosity while still delivering high reactivity, enabling improved sprayability and superior appearance in the final coating. This conversion to lower VOC has unlocked greater potential in utilizing waterborne options. BASF Resins offers two primary grades for achieving performance requirements in formulation.

Basonol^® AC 2120 W

An acrylic multistage polyol which is delivered with 6.6% PnB to allow Part A to be very low VOC and deliver excellent chemical resistance and gloss when combined with hydrophilically modified isocyanates and hydrophobic isocyanates like Basonat HW 2100 and Basonat HI 3100.

Joncryl^®587-AC &
Joncryl^® 906-AC

Both products cut in an exempt solvent, acetone, which means the solvent to reduce viscosity does to impact the VOC level of the finished coating and allows for lower solids systems to be constructed. Joncryl 906-AC is well suited to offer a balance of high hardness development with fast cure times and can be used as a modifying resin.

Joncryl^® 963

A 100% solids flexible acrylic polyol

Joncryl^® RPD 980-B

A high solid, rapid property development polymer suited well for blending for clear coats, basecoats and primers. This product offers the advantage of starting high solids, good flow characteristics, with a balance of pot life and tack free times.

Joncryl^® OH 8710

A non-VOC containing polyol dispersion which provides great flow on application and provides more compatibility with hydrophobic polyisocyanates versus traditional primary dispersions.
Both waterborne polyol dispersions allow for compatibilization with secondary dispersions where blending is preferred.

Joncryl^® xDTM-B &
Sovermol^® 1055

Formulating clear coats with Joncryl XDTM‑B in combination with Sovermol 1055 delivers a significant viscosity reduction, enabling easier spray application without sacrificing performance. Sovermol 1055, an epoxy‑functional reactive diluent, effectively lowers viscosity and reduces the amount of solvent required to achieve sprayable conditions. This directly supports lower VOC levels, improved processing efficiency, and stronger alignment with tightening regulatory demands. The synergy between Joncryl XDTM‑B’s high reactivity and Sovermol 1055’s diluent functionality empowers formulators to design higher‑solids, more sustainable coatings. Together, they provide a compelling platform for next‑generation clear coat systems that balance performance, productivity, and environmental responsibility.

Sovermol^® 1092

A bio-based polyester polyol

The Additives That Make PCBTF‑Free Formulation Work

Additives play a critical role in performance in this new low VOC space without PCBTF, enabling coatings manufacturers to address key challenges such as effective viscosity control and the prevention of defects including craters and bubbles. Our approach prioritizes high-solids additives with distinct advantages: dispersants mitigate viscosity increases associated with pigment interactions, while defoamers and wetting agents address issues related to trapped gases and surface tension, thereby reducing the risk of crater formation.

While our additive selection can be system dependent, our product portfolio demonstrates significant versatility across various coating systems. We offer targeted solutions to address specific performance challenges encountered when developing PCBTF-free coatings.

For solvent-based pigmented systems, we recommend the use of dispersants to improve the overall handling and application of the coating, enhancing efficiency and flow characteristics.

Efka^® PX 4733

A versatile dispersing agent that is suitable for energy-curable and solvent-based systems, with broad pigment affinity, including matting agents and carbon black. It provides excellent color properties and viscosity reduction.

Efka^® PX 4780

An advanced high molecular weight dispersing agent which has excellent dispersing abilities and offers extremely good viscosity reduction for difficult pigments such as high color carbon black pigments, demonstrating best compatibility with PES and PUR resins used in solvent based automotive refinish coatings. It also has the capability to crosslink into PUR and melamine chemistries, offering enhanced film properties.

Our defoamer range also offers effective solutions for pigmented systems:

Efka^® PB 2021

A silicone-free defoamer, which is especially well suited for eliminating foam during solvent based spray applications.

Efka^® PB 2770

A polymer based, silicone-free defoamer that ensures efficient deaeration and foam control, in UV 100% solids applications, featuring excellent compatibility, superior recoatability, and minimal impact on surface appearance.
For solvent-based clearcoat applications, Efka PB 2770 remains an effective and compatible defoamer.

Efka^® SL 3299

A highly adaptable wetting agent for clearcoats, delivering enhanced wetting, flow, and leveling capabilities, along with desired slip properties to prevent dirt adhesion. It maintains strong compatibility for excellent appearance in solvent-based and is suitable for water-based systems.

FoamStar^® ST 2400

A silicone‑free defoamer that delivers very fast bubble break, excellent compatibility, and long‑term foam control in waterborne acrylic systems without surface defects or separation.

Loxanol^® CA grades

Low VOC coalescing agents, facilitating film curing in water-based applications.

Shaping the Future of Automotive Refinish

BASF Resins and Additives are primed to meet the challenges of removing PCBTF from refinish formulations with continual work focused on optimization. We are here to ensure our customers have the tools needed to meet regulatory changes without sacrificing performance.