ISO 1265:2007

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.