ISO 19252:2008

Overview

ISO 19252:2008 specifies a standardized laboratory method for determining the scratch properties of plastics under defined conditions. The test produces quantitative and qualitative data by moving a hardened scratch tip of specified geometry across a prepared test specimen while continuously recording scratch force, scratch-tip displacement, and scratch distance. The method supports both constant-load testing (to classify scratch behaviour and build a scratch map) and linearly increasing-load testing (to determine the critical normal load at which severe damage begins). The standard is applicable to uncoated and unlacquered thermoplastic and thermosetting moulding materials.

Key Topics and Requirements

• Test principle: A hard instrument moves along the specimen centreline under controlled load and speed while recording force and displacement.
• Scratch-tip specification: Hemispherical tip with radius R = 0.5 mm ± 0.025 mm; hardened to ≥ Rockwell HRC 64; polished to surface roughness < 0.20 µm.
• Measured outputs: Scratch force (horizontal), tip displacement (vertical), and scratch distance-used to classify scratch behaviour as ploughing, wedge formation, or cutting.
• Test modes:
  • Constant-load testing - used to map scratch behaviour across combinations of load and speed (scratch map).
  • Linearly increasing-load testing - used to determine the critical normal load (Pc) at a given speed.
• Apparatus and tolerances:
  • Load and speed controlled to ±1% (with other specified positional and timing tolerances).
  • Displacement gauge accuracy ±1 µm (static) and ±10 µm during test.
  • Specimen support must be flat and rigid; instrument inertia and machine deflection limits specified.
• Specimens & preparation:
  • Use Type A multipurpose specimens (ISO 3167), injection-moulded per ISO 294-1 or ISO 10724-1.
  • Dimensional measurements to ±0.01 mm; conditioning per ISO 291.
• Sampling guidance:
  • Scratch maps: recommended ≥25 different test-condition sets.
  • Critical load: three specimens per test speed; single or three specimens required depending on observed behaviour.

Applications

ISO 19252:2008 is used to:

• Compare scratch resistance between plastic grades and formulations.
• Support material selection in product design (e.g., consumer goods, automotive interiors, appliances) where surface durability matters.
• Provide quality-control or R&D data for polymer development and failure analysis.
• Generate scratch maps and critical-load values for specification, benchmarking, and supplier qualification.

Related Standards

• ISO 291 - Standard atmospheres for conditioning and testing
• ISO 294-1 - Injection moulding of thermoplastic test specimens
• ISO 3167 - Multipurpose test specimens
• ISO 10724-1 - Injection moulding of thermosetting powder moulding compounds

Keywords: ISO 19252:2008, plastics scratch testing, scratch properties, scratch map, critical normal load, scratch tip, thermoplastic, thermosetting.