ISO 13468-2:2021

Overview

ISO 13468-2:2021 sets out a standardized method for determining the total luminous transmittance of transparent and substantially colourless plastics. The standard specifies the use of a double-beam scanning spectrophotometer in the visible region of the spectrum, focusing on planar plastics, films, and sheets with a thickness up to 10 mm. This method is vital for quality control and material characterization in the plastics industry, facilitating reliable measurement of how much visible light passes through plastic materials.

This international standard is not suitable for plastics containing fluorescent materials. It complements ISO 13468-1, which provides a method for single-beam instruments.

Key Topics

• Total Luminous Transmittance Measurement

  • Determination of the proportion of incident visible light transmitted through a plastic specimen
  • Application to faintly tinted and substantially colourless materials

• Double-Beam Spectrophotometer Use

  • Specification of requirements for light sources, monochromators, optical systems, integrating spheres, and photodetectors
  • Ensures accurate, repeatable, and reproducible measurements in accordance with CIE standards

• Sample Requirements

  • Guidance on preparing defect-free samples from mouldings, films, or sheets
  • Specification on conditioning (standard atmosphere and temperature) before testing

• Reporting and Precision

  • Standardized methods for expressing results, including calculation procedures for spectral and total luminous transmittance
  • Instructions for preparing comprehensive test reports, ensuring global consistency

Applications

The procedures outlined in ISO 13468-2:2021 are widely used across several sectors, including:

• Plastic Manufacturing and Processing

  • Quality assessment of raw materials, films, and sheets
  • Validation of optical clarity for end products such as glazing, packaging, and displays

• Research and Development

  • Material comparison and development of new polymer blends with desired optical properties
  • Reliable benchmarking against international standards

• Product Specification and Compliance

  • Ensuring conformity with regulatory requirements or customer specifications related to light transmittance
  • Benchmarking materials for architectural, automotive, and electronic applications

• Testing Laboratories

  • Providing third-party validation of plastic transparency and ensuring consistency across batches

Related Standards

• ISO 13468-1: Plastics – Determination of the total luminous transmittance of transparent materials – Part 1: Single-beam instrument
• ISO 291: Plastics – Standard atmospheres for conditioning and testing
• ISO/CIE 11664-1 & ISO/CIE 11664-2: Colorimetry standards – Covering colorimetric observers and standard illuminants
• CIE Publication No. 15 & 17: Further colorimetry and lighting vocabulary, essential for interpreting and applying measurement results

Practical Value

By adopting ISO 13468-2:2021, organizations ensure reliable and comparable measurement of optical transmittance in plastics. Standardization facilitates trade, enhances product quality, and supports material selection for high-performance applications. Utilizing a double-beam spectrophotometer method reduces variability and increases confidence in test results, especially for transparent and colourless plastic components where light transmission is critical.

Keywords: ISO 13468-2, plastics testing, luminous transmittance, double-beam spectrophotometer, optical properties, transparent plastics, quality control, material characterization, light transmission, plastic films, plastic sheets, ASTM, ISO standards, colorimetry, laboratory testing, product compliance.