Overview
ISO 1265:2007 - Plastics - Poly(vinyl chloride) resins - Determination of number of impurities and foreign particles - defines a visual, quantitative method for assessing particulate contamination in flattened surfaces of poly(vinyl chloride) (PVC) resins. The standard specifies a controlled counting procedure using a glass plate with a 300 mm × 300 mm grid and a rigid backing plate covered with glazed white paper. It is not applicable to paste resins due to their finely divided state.
Key topics and requirements
- Scope: Method for counting visible impurities/foreign particles in PVC resin powders (flattened surface only).
- Test setup:
- Glass plate (specified dimensions) marked with a 300 mm × 300 mm grid of 100 squares (30 mm × 30 mm each).
- Rigid plate covered with glazed white paper as backing.
- Counting procedure:
- Resin is spread between the plates to cover at least 25 selected squares.
- Count coloured and black specks larger than 0.250 mm (visible to the naked eye) within the chosen 25 squares.
- Counting is done under good laboratory lighting from about 300 mm viewing distance and within a 2-minute interval (eye fatigue limit).
- Repeat counts follow the standard’s decision schedule to determine whether contamination is homogeneous or heterogeneous (up to four determinations).
- Result expression:
- The number of specks is extrapolated and reported as the number of specks per 100 squares.
- Clause 5 of the standard provides calculation rules, including treatment for highly contaminated samples that cannot be fully counted within the 2‑minute limit.
Applications and users
ISO 1265:2007 is practical for:
- PVC resin manufacturers conducting batch quality control and process monitoring.
- Quality assurance laboratories verifying visual particulate contamination levels before shipment or compounding.
- Purchasers and specifiers who require objective impurity counts for acceptance criteria in procurement contracts.
- Regulatory or certification bodies assessing compliance with product cleanliness requirements.
Benefits include a simple, reproducible inspection method that helps reduce downstream processing defects (e.g., discoloration, inclusions) and supports consistent supplier control.
Related standards
- ISO 1265:2007 was prepared by ISO/TC 61 (Plastics). For comprehensive PVC testing and material characterization, users commonly reference other ISO plastics test methods maintained by ISO/TC 61. Check national and industry standards for complementary tests on PVC resin properties and contamination limits.
Keywords: ISO 1265:2007, PVC resin testing, poly(vinyl chloride) resins, impurities, foreign particles, speck count, quality control.
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