Overview
ISO 22553-2:2019 - Paints and varnishes - Electro-deposition coatings - Part 2: Throwing power - specifies laboratory methods for determining the ability of electro-deposition (e-coat) materials to deposit film into recessed areas and cavities. The standard defines two test procedures (Method A: single-chamber; Method B: multiple-chamber), measurement and evaluation steps, and related apparatus and specimen preparation. Throwing power is a critical performance attribute for automotive and general industrial e-coatings because it influences dry-film thickness in cavities and thus corrosion protection.
Key Topics and Requirements
- Scope and applicability: Applies to electro-deposition coatings used in automotive and other industrial sectors (chillers, radiators, consumer products, aerospace, agriculture).
- Two test methods:
- Method A - Single-chamber: Uses a laboratory deposition system with a rack-mounted test specimen and larger test panels (~300 × 105 × 0.75 mm). Typical immersion depth and controlled bath circulation/stirring are specified. Dry-film thickness is measured on the inside every 5 cm from the lower edge.
- Method B - Multiple-chamber: Uses stacked panels and spacers (panels ~150 × 70 × 0.75 mm) with holes to allow controlled ingress. Multiple internal chambers simulate progressive penetration into cavities.
- Apparatus & tolerances: Film-thickness measuring device with max permissible error of 0.1 µm; ovens with temperature control (e.g., ±2 °C up to 150 °C); accurate thermometers, timers and rulers.
- Specimen preparation: Electrically conductive, pretreated panels per ISO 1514; masking, spacers and defined mounting arrangements to ensure reproducible deposition.
- Evaluation: Measure dry-film thickness (ISO 2808 methods), determine the end of coating penetration and outside film thickness; single determination is standard practice.
- Supporting requirements: References and cross-links to ISO 22553-1 (vocabulary), ISO 4618 (terms), ISO 1514 (test panels), ISO 2808 (film thickness) and ISO 23321 (demineralized water).
Applications and Users
- Primary users: Coating formulators, e-coat laboratories, quality control teams, automotive OEMs and tier suppliers, corrosion testing laboratories.
- Practical uses:
- Assess and compare throwing power of different e-coat formulations.
- Validate process settings (voltage, bath temperature, circulation) for coating lines.
- Support product development, specification compliance, and failure investigation where cavity coverage and corrosion protection are critical.
Related Standards
- ISO 22553-1 - Vocabulary for electro-deposition coatings
- ISO 1514 - Standard panels for testing
- ISO 2808 - Determination of film thickness
- ISO 4618 - Terms and definitions (paints and varnishes)
- ISO 23321 - Demineralized water for industrial applications
Keywords: ISO 22553-2, throwing power, electro-deposition coatings, e-coat, film thickness, electrocoat testing, automotive coatings, laboratory methods.