1. The two main families: water-based and solvent-based
Coating technology historically divided into two large families that remain today: solvent-based paints and varnishes (toluene, xylene, hexane, ethyl acetate, methyl ethyl ketone, aliphatic hydrocarbons) and water-based paints, where the vehicle is a dispersion of resin in aqueous medium stabilized by surfactants.
Modern architectural paints (latex paints, acrylic paints for walls) are almost entirely water-based for environmental and occupational health reasons; industrial, marine, automotive and high-performance wood paints still use solvent on a large scale due to adhesion, cure and resistance requirements.
The practical consequence of this division in pump specification is huge: a water-based paint line can operate in a non-classified area (no ATEX/INMETRO) and use FBCN in cast iron or 316L with common motorization; a parallel solvent paint line needs to operate in Zone 1 (probable presence of flammable vapor) with minimum Ex d IIB T3 motorization, equipotential grounding, anti-spark coupling and intrinsically safe instrumentation.
A single factory may contain both architectures side by side, physically separated by fire walls and with dedicated exhaust in the solvent area.
2. Base resins: alkyd, epoxy, polyester, polyurethane, acrylic
Resins are the structural ingredients of paints and varnishes — the component that forms the film after drying or curing.
The five main families in the Brazilian market are: (1) alkyd resins, based on vegetable oils modified with polycarboxylic acids, used in wood paints and industrial enamels; (2) epoxy resins, obtained by the reaction of bisphenol A with epichlorohydrin, used in high-performance industrial anticorrosive painting; (3) polyester resins, used in powder paints and industrial coatings; (4) polyurethane resins, used in high-performance varnishes and automotive paints; (5) acrylic and vinyl resins, dominant in water-based architectural paints.
Each family is produced in synthesis reactors that generate intermediates with increasing viscosities throughout the reaction.
Resin manufacturing is a critical pumping point because viscosity varies dramatically throughout the cycle: an alkyd resin can start the reaction at 500 cP and end at 50,000 cP, requiring a pump that operates stably in this range — external FBE serves well up to about 10,000 cP, above this internal FBEI is more appropriate, and for extreme viscosities (above 50,000 cP) lobe or screw pumps are preferable.
FB Bombas covers the resin manufacturing chain up to approximately 50,000 cP with the FBE + FBEI + FBOT (thermal oil reactor heating) combination — the upper range of 50,000 to 500,000 cP falls to specialized high-viscosity pump suppliers.
3. Pigment dispersion: grinding and abrasive recirculation
The pigment dispersion stage is one of the most abrasive in the paint manufacturing process. Pigments — titanium dioxide, iron oxides, phthalocyanines, calcium carbonates, silicates — arrive as hard particle powders (Mohs hardness 6-8 for TiO₂, 6-7 for iron oxides) that must be ground and dispersed in the vehicle (resin + solvent or resin + water) until reaching specific fineness measured on the Hegman scale.
The classic process uses bead mills where the pigment+vehicle mixture is repeatedly recirculated between the pump, the mill and the equalization tank, with the pump suffering accelerated wear due to the mineral fraction not yet fully dispersed.
For pigment grinding recirculation, the recommendation is external gear FBE in hardened carbon steel casing or FBCN with semi-open impeller recoverable by cover adjustment. Typical impeller life under these conditions is 6 to 12 months versus the 5-10 years expected in clean water service — wear is an expected operational cost, not an equipment failure.
For dispersions with high TiO₂ content (high-coverage white paints), the recommendation may migrate to tungsten carbide or ceramic-coated pumps — a range where FB Bombas does not compete.
4. Solvent-based paints: ATEX/INMETRO compliance
Industrial, marine, automotive and high-performance wood paints are still predominantly solvent-based, and this fact imposes additional rigor on pump specification. The manufacturing area of a solvent paint line is typically classified as Zone 1 (probable presence of explosive atmosphere during normal operation) or Zone 2 (improbable presence).
Electrical design follows NBR IEC 60079-10-1 for classification, NBR IEC 60079-14 for installation, and mandatory certification in Brazil is INMETRO per Ordinance 179/2010 — not replaceable by European ATEX.
For pumps on a solvent paint line, the standard configuration includes: Ex d IIB T3 electric motor (toluene, xylene) or Ex d IIA T3 (for lower-temperature-class solvents), pump-motor coupling with bronze or non-metallic composite anti-spark guard, equipotential grounding between pump, motor and base periodically verified, intrinsically safe Ex ia or Ex d instrumentation, and dedicated ventilation in the enclosure.
FB Bombas supplies the complete set pre-certified INMETRO via partnership with WEG or Siemens, eliminating the need for the customer to manage multi-vendor certifications. FBE, FBEI and FBCN pumps can be specified in this configuration according to product viscosity.
5. Cleaning and color change: the operational bottleneck
An almost universal characteristic of the paint industry is the large variety of SKUs (up to thousands in a medium-sized factory) produced on shared equipment. Each color or formulation change requires complete cleaning of the pump, piping, mixer and filler with compatible solvent (in solvent-based paints) or water with detergent (in water-based paints).
The pump needs to be designed to facilitate this cleaning — without dead legs, with complete gravity drainage, with connections that allow quick disassembly for manual cleaning in cases of strong pigmentation (black, red) followed by light color (white, cream).
In pump terms, the recommendation is FBE or FBEI with tri-clamp flanges or quick connections, lower drainage plugs on each chamber, cartridge mechanical seal easily removable without dismantling piping, and internal design that minimizes sharp corners where paint can be retained. Time between two colors is a critical KPI of operation, frequently measured in minutes, and correct choice of pump design can reduce change time by 30-50% compared to generic pumps not specified for this application.
