ISO 2285:2019

Overview

ISO 2285:2019 specifies laboratory methods for measuring dimensional changes in vulcanized or thermoplastic rubber during and after tensile loading for relatively short periods. It covers two principal test types: tension set under constant elongation and tension set, elongation and creep under constant tensile load. Tests are intended to assess elastic properties of rubber in the hardness range 20 IRHD to 94 IRHD, at standard laboratory temperature or at elevated temperatures where specified.

Key Topics and Requirements

• Test types
  • Constant-elongation test: measures the ability of rubber to retain elastic properties after being extended to a specified strain for a defined time and then released.
  • Constant-load test: determines elongation, creep, and tension set when a specimen is subjected to a constant tensile load.
• Specimens and preparation
  • Strip specimens, strip with enlarged ends, and ring specimens; typical sheet thickness 2 mm ± 0.2 mm (large rings 4 mm ± 0.2 mm).
  • Preparation and conditioning in accordance with ISO 23529.
• Apparatus and measurement
  • Straining devices (clamps, pulleys, weights), ovens for elevated-temperature tests (per ISO 188), and length-measuring devices capable of 0.1 mm resolution.
  • Width/thickness measurement capability to 0.05 mm for die-cut pieces where applicable.
  • Calibration of test equipment per the schedule in Annex A (and ISO 18899 guidance).
• Scope limits and notes
  • Creep results from ISO 2285 are not suitable for product design or low-creep material evaluation; ISO 8013 applies for those cases.
  • The constant-load test is primarily used to assess state of cure and for quality control of thin-walled rubber products - increased crosslinking normally reduces set, creep and elongation.

Applications and Who Uses It

• Quality control laboratories in rubber manufacturing for routine batch verification.
• R&D and materials testing teams assessing vulcanizate elasticity and cure characteristics.
• Production engineers monitoring state of cure in thin-walled components (hoses, seals, gaskets).
• Suppliers and specifiers who require reproducible measures of tension set, elongation and short-term creep for material comparison and acceptance testing.

Related Standards

• ISO 23529 - specimen preparation and conditioning
• ISO 188 - accelerated ageing and heat resistance; oven requirements
• ISO 18899:2013 - calibration of test equipment
• ISO 8013 - determination of creep for product design / low-creep materials

Keywords: ISO 2285:2019, tension set, constant elongation, constant load, rubber testing, vulcanized rubber, thermoplastic rubber, creep, state of cure, quality control.