ISO 4664-3:2021

Overview

ISO 4664-3:2021 - Rubber, vulcanized or thermoplastic - Determination of dynamic properties - Part 3: Glass transition temperature (Tg) specifies a standardized method to determine the glass transition temperature (Tg) of vulcanized and thermoplastic rubbers in the hardness range 30–80 IRHD. The method uses a temperature sweep under controlled sinusoidal deformation (dynamic mechanical testing) and identifies Tg as the peak in the tan δ (loss factor) versus temperature curve. Tg obtained by this dynamic method is intended as a guideline to the material’s service temperature.

Key topics and requirements

• Measurement principle: Dynamic mechanical analysis (DMA)-style temperature ramp with sinusoidal deformation; Tg = temperature at maximum tan δ.
• Material range: Vulcanized or thermoplastic rubbers, hardness 30–80 IRHD.
• Test modes & specimens:
  • Compression cylinder: 10 mm height × 10 mm diameter (preferred).
  • Tension strip: preferred dimensions 25 mm length, 10 mm width, 2.0 ± 0.2 mm thickness with 10 mm test length.
  • Shear: sandwich construction with rubber elements bonded to metal cylinders.
• Apparatus performance:
  • Force readout accuracy ±1.0%.
  • Loss factor (tan δ) accuracy ±5% or ±0.02 (whichever smaller).
  • Sinusoidal wave with <10% harmonic content.
  • Test chamber temperature control to ±0.3 °C and local sample temperature monitoring.
• Test conditions:
  • Frequency range 1–15 Hz (recommended values in ISO 4664-1).
  • Strain amplitude per equipment manual (tolerance ±0.01%).
  • Temperature ramp: if unknown material, −150 °C to +70 °C at 1 or 2 °C/min; otherwise start ≥30 °C below expected Tg.
• Procedure & reproducibility:
  • Minimum three test specimens.
  • Condition specimens per ISO 23529 (≥3 h at standard laboratory temperature).
  • Dynamic measurement after at least six cycles of stress.

Applications

• Assessing service temperature limits and low-temperature performance of elastomers.
• Material selection and specification for automotive seals, vibration isolators, hoses, gaskets, footwear soles, and other rubber components.
• Quality control, R&D and comparative evaluation of compound formulations and curing processes.
• Inputs for finite-element simulations and lifetime/embrittlement assessments where viscoelastic transition matters.

Who uses this standard

• Test laboratories and QA/QC teams performing rubber testing.
• R&D engineers formulating elastomer compounds.
• Manufacturers of rubber components and suppliers verifying material performance.
• Regulatory and specification writers requiring standardized Tg data.

Related standards

• ISO 4664-1:2011 - General guidance for determination of dynamic properties.
• ISO 23529 - Preparation and conditioning of test pieces for physical tests.

Keywords: ISO 4664-3, glass transition temperature, Tg, rubber testing, dynamic mechanical analysis, DMA, tan delta, vulcanized rubber, thermoplastic rubber, IRHD.