Overview
EN ISO 1265:2007 (ISO 1265:2007) specifies a simple, reproducible method for determining the number of impurities and foreign particles on a flattened surface of poly(vinyl chloride) (PVC) resin. The procedure counts visible specks (particles > 0.250 mm) on a prepared sample area and expresses results by extrapolation as the number of specks per 100 grid squares. Not applicable to paste resins. This is a CEN-adopted international standard used for PVC resin quality control.
Key topics and technical requirements
- Scope & limitation
- Applies to powdered PVC resins; excludes paste resins due to their finely divided state.
- Counts only particles clearly visible to the naked eye (> 0.250 mm).
- Principle
- Flatten a resin sample between a rigid, glazed white surface and a glass plate that carries a 300 mm × 300 mm grid of 100 squares (30 mm × 30 mm).
- Count specks in a selected group of 25 squares and extrapolate to 100 squares.
- Apparatus (examples given in the standard)
- Glass plate (approx. 340 × 340 × 4.5 mm) marked with a 300 × 300 mm grid of 100 squares.
- Rigid plate (approx. 450 × 450 mm) covered with glazed white paper.
- Timer/stopwatch and photographic reference scale for particle-size reference.
- Procedure & timing
- Spread a test sample (standard indicates about 200 cm of sample) and place the glass plate; ensure contact over at least 25 squares.
- Count within 2 minutes (maximum) from ~300 mm viewing distance under good lighting.
- Repeat counts according to the decision rules: if counts differ by less than the tolerance the contamination is considered homogeneous; larger differences trigger additional determinations.
- Expression of results
- Results are reported as the number of specks per 100 squares using the formulas and decision rules provided in Clause 5 (e.g., highly contaminated samples use P = (n × 100)/S).
- Test report
- Must include product identification, reference to the standard, result, unusual observations, and date of test.
Applications and users
- Quality control and acceptance testing in PVC resin manufacturing.
- Incoming inspection by converters, compounders, and compound quality laboratories.
- Production troubleshooting and process improvement to reduce particulate contamination.
- Purchasing/acceptance testing by buyers and regulatory compliance checks.
Related standards / context
- Internationally prepared by ISO/TC 61 (Plastics); second edition revises ISO 1265:1979.
- Published and endorsed as EN ISO 1265:2007 by CEN for European national standards bodies.
Keywords: EN ISO 1265:2007, ISO 1265:2007, PVC resin impurities, poly(vinyl chloride) resins, determination of impurities, foreign particles, PVC quality control, particle count method.
