Overview
EN ISO 13632:2012 - "Binders for paints and varnishes - Rosin - Sampling and sample preparation for colour measurement" specifies standardized procedures for taking and preparing rosin (and rosin derivatives) samples for colour assessment. It covers sampling from drums, molten/liquid material, and solid forms such as flakes, pellets or pastilles, and describes how to prepare neat rosin or rosin-in-solution specimens for colour measurement. The standard references the colour-measurement methods in ISO 4630-1/2 and ASTM D509 and includes an informative Annex on correlating the USDA and Gardner colour scales.
Key Topics and Requirements
- Scope of samples: Sampling from drums, molten/liquid rosin, flakes, pellets or pastilles. Samples must be freshly broken and free of dust or finely divided material.
- Neat rosin preparation (Gardner):
- Melt sufficient material in a clean container under inert atmosphere (oven, hotplate, heat gun, sand or oil bath).
- Avoid overheating and bubble formation; stir slowly.
- Time from start of heating to pouring must not exceed 15 minutes.
- Pour molten rosin into a test tube or cuvette and measure colour while still molten.
- Rosin in solution (Gardner):
- Prepare a 50.0:50.0 (by mass) solution in analytical-grade toluene; dissolve at room temperature and pour into a cuvette.
- Preparation-to-pour time ≤ 15 minutes.
- USDA method:
- Melt and pour molten rosin into a mould forming a 22.2 mm cube (viewing direction).
- Same 15-minute heating-to-pour limit applies.
- Measurement and reporting:
- Colour measurement performed per ISO 4630-1/2 (Gardner) or ASTM D509 (USDA).
- Test reports must state the sample-preparation method used.
- Scale correlation:
- Annex A provides a method to correlate Gardner and USDA scales, accounting for different path lengths (approx. 10 mm test tube/cuvette vs 22.2 mm USDA cube) and using transmittance corrections (Beer’s law assumption) and CIE x,y,Y data.
Applications and Users
- Quality control laboratories testing rosin colour for paints, varnishes and adhesives.
- Rosin producers and processors who need consistent sampling and colour reporting.
- Paint and varnish formulators and raw-material procurement teams specifying rosin colour limits.
- Third‑party test houses and certification bodies performing standardized colour assessments.
- R&D teams comparing historical USDA data with Gardner-scale results using the Annex A correlation.
Related Standards
- ISO 4630-1: Gardner colour scale - visual method
- ISO 4630-2: Gardner colour scale - spectrophotometric method
- ASTM D509: Sampling and grading rosin (USDA colour)
- ASTM D1544, ASTM D6166 and relevant national standards (e.g., GB/T 8145/8146) for related test methods
Keywords: EN ISO 13632:2012, rosin sampling, sample preparation, colour measurement, Gardner scale, USDA scale, binders for paints, varnishes, rosin colour.
