Choose anti-corrosion coating additives by the first formulation failure: pigment dispersion, entrained air, or surface flow. CHLUMICRYL® DP-D200R is the solventborne grind-stage dispersant route, CHLUMICRYL® DF-D982V is the solvent/UV grind-stage defoamer route for pigmented systems, and CHLUMIAG® 3467 is the compatibility-prioritized surface-control route.
None of these products creates corrosion protection by itself. Protection depends on substrate preparation, pretreatment, resin and pigment package, pigment volume concentration, dry-film thickness, holidays, adhesion, cure, topcoat compatibility, and the service environment. An attractive drawdown cannot replace corrosion testing of the complete coating system.
Anti-corrosion additive decision map
| First repeatable failure | First route | Corrosion-system guardrail |
|---|---|---|
| High grind viscosity, weak pigment/bentonite dispersion, settling, or poor color development | DP-D200R | PVC, storage, adhesion, water uptake, blistering, and corrosion exposure |
| Grinding/application traps foam or microbubbles in a solvent/UV pigmented coating | DF-D982V | Not varnish; check craters, film continuity, gloss, storage, and corrosion |
| Dispersion and air release pass but flow, compatibility, or cratering still fails | CHLUMIAG® 3467 | Intercoat adhesion, cure, water/chemical resistance, and corrosion exposure |
| Prodotto | Published system and composition | Supplier guidance | Important boundary |
|---|---|---|---|
| CHLUMICRYL® DP-D200R | 50% active polyamide-polyester solution in dipropylene glycol methyl ether; solvent-based | Add to grinding material, mix, then add pigment | Published for organic bentonite and anti-corrosion coating systems; dosage requires current TDS |
| CHLUMICRYL® DF-D982V | Polysiloxane compound with hydrophobic particles; ≥95% solids; solvent and UV | 0.2–1%; add to grind for foam inhibition and microfoam removal | Not applicable to varnish; stir stored material; diluted solution lasts only 1–2 days |
| CHLUMIAG® 3467 | 100% active modified polysiloxane; water, solvent, and UV systems | 0.05–1% for solvent coatings; separate water/resin-modification guidance | Compatibility is prioritized; do not transfer resin-modification instructions without review |
Use DP-D200R when the grind is the first failure
DP-D200R is explicitly recommended for solvent-based anti-corrosion coatings and organic bentonite slurries. It is intended to improve dispersion and reduce viscosity, with possible gains in gloss, color strength, transparency, and hiding power. Add it to the grind vehicle before pigment, following the published order.
Establish a demand curve against grind viscosity, particle size or fineness, color strength, gloss, settling, and storage. Then repeat adhesion, water/chemical resistance, blistering, scribe creep, and corrosion exposure. A lower grind viscosity is useful only if pigment packing and barrier performance remain acceptable.
Use DF-D982V when microfoam threatens film continuity
DF-D982V is a high-solids defoamer for solvent and UV systems. The supplier calls for grind-stage addition to improve foam inhibition and defoaming speed. Its hydrophobic particles may settle during storage, so remix before use.
Do not use it as the clear-varnish route because the product page excludes varnish. If diluted with solvent, use the solution within the published 1–2 day window and validate stability. Measure foam, microbubbles, craters, pinholes, gloss, film continuity, adhesion, and corrosion results together.
Use 3467 after dispersion and air release pass
3467 is relevant when a stable pigmented coating still has compatibility, cratering, or flow problems. Its broad system fit and compatibility-prioritized positioning make it a reasonable surface-control screen, but it does not replace the dispersant or defoamer stages.
Use the guidance for the actual coating route. The product page publishes different ranges for solvent coatings, water-based systems, and resin modification. Confirm intercoat adhesion, topcoat compatibility, cure, water uptake, chemical resistance, and corrosion performance at every candidate level.
Control the corrosion panel before comparing additives
- Standardize steel and preparation. Record alloy, condition, cleaning/blast profile, pretreatment, and time to coating.
- Standardize formulation. Hold resin, anticorrosive pigment, PVC, extender, solvent, catalyst, and solids constant.
- Standardize application. Use the same wet/dry film thickness, stripe coat, flash, cure, edge treatment, and intentional scribe.
- Change one route at a time. Compare a blank and a compact ladder inside current supplier guidance.
- Use replicates. Corrosion chambers and coated specimens vary; one panel is not sufficient evidence.
Use corrosion methods correctly
ASTM B117 defines operation of salt-spray apparatus but does not prescribe a universal exposure time or interpretation. ASTM also cautions that standalone salt-spray results do not reliably predict natural-service performance. ASTM D1654 covers evaluation of coated specimens after corrosive exposure, including scribe creep, blistering, adhesion loss, and other failure. ASTM D610 addresses visible rusting on painted steel.
Agree the substrate, preparation, film build, scribe, cure, chamber method, duration, inspection interval, replicates, and acceptance criteria. Pair accelerated exposure with service-relevant cyclic, immersion, humidity, or field data when required.
Common false approvals
Grind viscosity falls, so corrosion performance is assumed better
Recheck pigment distribution, settling, permeability, blistering, adhesion, scribe creep, and rusting. Dispersion is a formulation control, not the corrosion result.
Microfoam disappears, but craters appear
Reduce DF-D982V and review incorporation, compatibility, contamination, and storage. Any discontinuity can become a corrosion pathway.
The unscribed panel passes but the scribe creeps
Investigate preparation, pretreatment, adhesion, pigment package, cure, and underfilm corrosion. Report unscribed and scribed behavior separately.
Related diagnostic guides
Use the pigmented-coating dispersant guide for a broader grind diagnosis, the pinhole guide for air/outgassing/dewetting defects, or the waterborne primer guide when waterborne compatibility is the first boundary.
Request an anti-corrosion coating trial
Send the resin, solvent/water/UV system, anticorrosive pigment and PVC, fillers/bentonite, grind data, steel preparation and pretreatment, film build, cure, defect photos, current additives, and corrosion method/acceptance criteria. Ask Longchang Chemical to compare DP-D200R, DF-D982V, or 3467.