Overview
ISO 12625-4:2022 specifies a tensile test method for tissue paper and tissue products. The standard defines how to measure tensile strength, stretch at maximum force, and tensile energy absorption (TEA) using a tensile-testing apparatus operating at a constant rate of elongation. It also gives procedures to calculate the tensile index and the tensile energy absorption index. Annex B (new in this edition) provides an optional method for determining tensile modulus; precision data are in Annex A.
Key topics and requirements
- Test principle: stretch a calibrated test piece to break while recording force vs. elongation; integrate the area under the curve to obtain TEA.
- Apparatus: tensile tester compliant with ISO 1924-2 and ISO 7500-1 for force calibration; means to measure area of the force–elongation curve to ±2% accuracy.
- Rate of elongation: 50% of initial span per minute (e.g., 50 mm/min for a 100 mm span; 25 mm/min for a 50 mm span).
- Start of elongation measurement: at a force of (0.25 ± 0.05) N (slack correction applied).
- Force accuracy: load cell accuracy of ±1% of reading or ±0.025 N, whichever is greater.
- Clamps and span: clamps at least 50 mm wide, clamping lines parallel within 1°; standard test span (100 ± 1) mm, or (50 ± 1) mm for small finished products.
- Test-piece dimensions: 50.0 ± 0.5 mm width and at least 150 mm length (shorter permitted for some finished products with corresponding span adjustments).
- Sampling and conditioning: condition samples per ISO 187; select representative samples per ISO 186.
- Sample count: minimum 10 test pieces in machine direction and 10 in cross direction (total ≥20).
- Calculations: tensile strength, tensile index (tensile strength ÷ grammage), stretch at maximum force (percentage), TEA and TEA index (TEA ÷ grammage).
- Reporting: include test conditions, apparatus details, span, number of test pieces and calculated indices.
Applications and users
ISO 12625-4:2022 is used for quality control, product development, specification compliance and comparative testing of tissue grades and finished tissue products. Typical users:
- Tissue manufacturers and converters (product R&D, process control)
- Third‑party testing laboratories and QA departments
- Raw material suppliers and formulators assessing strength and softness trade-offs
- Procurement and compliance teams specifying mechanical performance
- Standards bodies and regulatory organizations
Related standards
Keywords: ISO 12625-4:2022, tissue paper tensile test, tensile strength, tensile energy absorption, tensile index, stretch at maximum force, tissue products testing.