What Pros Really Mean by the types of additives in paint

If you work with coatings day-to-day, you know additives are the unsung heroes. They tune flow, kill foam, resist UV, stop rust, and frankly save jobs from callbacks. In the last two years, I’ve seen fast shifts: lower-VOC coalescents, cobalt-free driers, PFAS scrutiny on slip agents, and tighter biocide regulations. It sounds dry, but the stakes are real—finish quality, warranty claims, and compliance.

Core families of types of additives in paint include: dispersants/wetting agents (pigment stability and easier grind), defoamers and deaerators (micro-foam under airless spray is still a pain), rheology modifiers (HEUR, HASE, cellulosics) for sag vs. leveling, anti-skinning (MEKO alternatives), driers (manganese/zirconium, cobalt-free), corrosion inhibitors (zinc phosphate, organic salts), adhesion promoters (silane systems), UV absorbers and HALS for exterior durability, biocides (in-can MIT/BIT and dry-film actives), matting agents (amorphous silica), slip/leveling agents (silicone/fluorinated—PFAS-free options gaining), freeze–thaw stabilizers (glycols), and stain-blockers for wood and masonry. In real life, you might only tweak 3–5 at a time, but they’re doing a lot of heavy lifting.

Trends and where they land

• Low-VOC, low-odor: new coalescents and surfactant packages to hit 50 g/L or less without wrecking scrub resistance.
• Biocide pressure: formulators balancing MIT/BIT limits with in-can stability; some move to multi-barrier strategies.
• Cobalt-free driers: better yellowing control; cure profiling tweaked with secondary driers.
• PFAS scrutiny: more silicone-acrylate and hyperbranched alternatives for slip-leveling.

Process flow the lab actually uses

Materials: resin/binder, pigment/extenders, water/solvent, grind aids (dispersant + wetting), then letdown with defoamer, rheology modifiers, coalescent, slip/leveling, biocides, driers if alkyd. Methods: high-speed disperse to a Hegman 6–7 (≈ 15–25 µm), then viscosity target via KU and ICI. Testing standards: adhesion ASTM D3359, gloss at 20°/60°, scrub ASTM D2486, corrosion ASTM B117, QUV per ASTM G154, hardness ASTM D3363, and water resistance ISO 2812. Service life: interior acrylics 7–10 years paint-to-paint; exterior architectural 5–12 years depending on UV/HALS load; industrial primers 1,000–1,500 h salt spray with robust inhibitor packages—real-world use may vary.

Application snapshots

• Architectural: anti-spatter rheology, surfactant leaching control, stain resistance for kitchens.
• Wood/industrial: cobalt-free driers, flow agents to squash craters, mar resistance boosters.
• Marine/steel: high-build rheology, strong anti-corrosion pigments, robust deaeration.
• Automotive refinish: silicone-managed slip for DOI, fast-dry drier balance, defoamers tuned for HVLP.

Customer feedback lately? Many contractors say better leveling is beating “orange peel” even at low temps; facility managers are chasing longer scrub cycles and fewer touch-ups; R&D folks admit, surprisingly, that one well-chosen dispersant can rescue a noisy grind faster than throwing more defoamer at it.

Product spotlight (safety-first note)

Potassium chlorate (KClO3) is an oxidizing chemical occasionally referenced in specialty research contexts—not a routine paint additive. It belongs to Hazard Class 5.1 and must be handled under strict safety and regulatory controls. If you encounter it in a materials list, double-check compliance and transport classifications before anything else.

Vendor comparison (indicative)

Case studies (short and real-world)

Architectural eggshell: Swapped legacy surfactant for a low-foam wetting agent and added a silicone-acrylate leveler; complaints of roller marks dropped by ~40% in field reports, gloss kept within ±2 @60° after 200 scrub cycles.

Steel primer: Shifted to a zinc-phosphate/organic inhibitor blend and adjusted HEUR package. Achieved 1,200 h ASTM B117 with acceptable blistering (≤ 6F) and improved edge retention. To be honest, the deaerator tweak mattered more than anyone expected.

Bottom line: choose the right types of additives in paint for the substrate, environment, and regulations you live under. Test, don’t guess—then write it into your SOP so the next shift doesn’t reinvent the formula.

Authoritative citations

1. ASTM D3359 — Standard Test Methods for Rating Adhesion by Tape Test.
2. ASTM B117 — Standard Practice for Operating Salt Spray (Fog) Apparatus.
3. ASTM G154 — Operating Fluorescent UV Lamp Apparatus for Exposure of Nonmetallic Materials.
4. ASTM D2486 — Scrub Resistance of Wall Paints.
5. ISO 12944 — Paints and varnishes — Corrosion protection of steel structures by protective paint systems.
6. ISO 2812 — Determination of resistance to liquids.
7. US EPA 40 CFR Part 59 — National Volatile Organic Compound Emission Standards for Consumer and Commercial Products.
8. ECHA guidance on MIT/BIT and biocidal product regulation (BPR).