Industrial Coatings
Industrial and protective coatings cover a wide range of binders and film builds, from thin shop primers to heavy-duty systems on steel and concrete. The colour paste therefore has to be broadly compatible, cost-effective at let-down, and stable in systems that cure at ambient temperature, because a paste that only works in one binder forces a separate inventory for every product line. Field application also means the coating is mixed and applied under conditions the formulator never sees, so tolerance to variation matters as much as laboratory performance.
Key Requirements in This Application
Broad binder compatibility
Epoxy, polyurethane, alkyd, acrylic and chlorinated rubber systems are all used in this segment. The carrier must wet and stabilise pigment in each without causing seeding, craters or viscosity drift, which is why resin-free carriers are often preferred as a common base across several product lines.
Corrosion resistance and adhesion
Protective films must hold adhesion to blasted steel and resist undercutting at scribes. The paste must not introduce water-soluble ionic species or free components that plasticise the film and weaken the bond at the interface.
Colour stability and hiding
Safety colours, machinery colours and pipeline identification depend on consistent chroma and adequate hiding at the specified film build. Poorly dispersed pigment reduces hiding and forces higher loading, which in turn raises viscosity and cost.
Let-down economics
Industrial coatings are cost-sensitive, so a high pigment load in the paste and a predictable let-down ratio matter as much as the colour itself. Over-dosing to compensate for weak dispersion is a common and avoidable cost in this segment.
Application window
Brush, roller and airless spray each impose different rheology. A paste that raises viscosity sharply at the required loading will shorten pot life or make the coating difficult to atomise in the field, particularly when the coating is applied at low ambient temperature.
Overcoating and recoat interval
Protective systems are built up in several coats, and the recoat window is usually defined by the binder. A paste that extends the interval between coats, or that leaves a surface too smooth or too waxy for the next coat, disrupts line scheduling and can cause intercoat delamination that only appears years later.
Substrate variety
The same product may be specified over carbon steel, galvanised steel, aluminium or concrete. Each substrate has a different surface energy and porosity, so the paste must not depend on a single surface chemistry for adhesion, and it must not be drawn unevenly into a porous substrate and leave a patchy film.
Recommended DENSON Series
Resin-free carrier pastes intended as a universal base for many binder types, which simplifies inventory where one plant runs several coating lines. The carrier adds no resin of its own, so the binder system remains a formulator decision; it contains solvent and is not a solvent-free product.
View seriesOil-based pastes for solvent-borne industrial systems, with approximately 20 percent PMA in the carrier, suited to acrylic, polyester and alkyd let-down where a familiar solvent balance is preferred.
View seriesSolvent-free epoxy colour pastes for solvent-free primer and topcoat systems, where no solvent may remain in the film and where odour or retained volatile would be a problem in a confined space.
View seriesTechnical Considerations
- Fix the let-down ratio with a gradient trial on the actual binder, because the same paste behaves differently in epoxy and in alkyd.
- Check compatibility before scaling up: a small laboratory draw-down will show seeding or craters that only appear after the batch is made.
- For solvent-free epoxy systems, confirm that every component is genuinely solvent-free; adding a solvent-borne paste defeats the purpose of the system.
- Watch pot life when the paste raises the viscosity of a two-pack product, and adjust pigment loading rather than thinning beyond the specified VOC.
- Re-test adhesion and salt spray after any change of paste grade, since carrier components can plasticise the film even when the colour matches.
- Confirm the recoat window on the finished system, because a paste that changes surface energy can push the next coat outside its adhesion window.
Testing and Compliance
Film performance
Adhesion is assessed by cross-cut to ISO 2409 and corrosion resistance by neutral salt spray to ISO 9227 on the specified substrate and film build, with scribe creep recorded over the exposure period.
Paste quality
Fineness by GB/T 6753.1, viscosity by GB/T 9751 and particle size distribution to ISO 13320 confirm that the dispersion is complete before the paste is let down into a production batch.
Storage and compatibility
Accelerated storage at elevated temperature is used to check settling, hard caking and viscosity drift, and to confirm that the paste remains redispersible after the shelf period expected in a warehouse.
Intercoat adhesion
Multi-coat systems are tested for adhesion between coats at the upper and lower limits of the recoat interval, because that is where a compatibility problem becomes a delamination in service rather than a visible defect at application.
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