Overview
ISO 16260:2016 - "Paper and board - Determination of internal bond strength" specifies a pendulum impact method for measuring the energy required to rapidly delaminate a test piece of paper or board in the Z (thickness) direction. The method is intended to simulate rapid impacts, impulses or shock loads experienced during printing and converting, and produces an internal bond strength value expressed as the potential energy absorbed per unit surface area.
Key technical topics and requirements
- Test principle: A square test piece is laminated between two pieces of double-sided adhesive tape, fixed between a rigid metal anvil and an L‑shaped aluminium platen. A pendulum of defined mass and length strikes the platen, initiating rapid delamination; absorbed energy is calculated from the pendulum over‑swing.
- Apparatus and calibration:
- Pendulum mounted on low‑friction bearings, free to swing ≥180°, with horizontal latch and vibration‑free release.
- Pendulum length specified as 228.6 ± 0.2 mm (reduced length verification method provided).
- Aluminium platen alloy: EN AW 6060 T66 (see EN 755‑2); platen mass and surface roughness and replacement criteria are specified.
- Adhesive tape specification: FINAT FTM1 adhesion characteristics (used for tape selection).
- Instrument/pendulum measuring ranges cover low to high energies (device options include different pendulum masses/augmenting weights and test-piece area reductions).
- Specimen preparation and limits:
- Test-piece widths of 25.4 mm ± 0.2 mm and controlled pressing during tape lamination.
- Method may be unsuitable for materials damaged by compression or porous materials that allow adhesive migration.
- Standards referenced and supporting content:
- Sampling and conditioning: ISO 186 and ISO 187 are normative references.
- Annexes provide precision data, maintenance/calibration guidance, and device compliance verification.
Practical applications and users
- Who uses it:
- Paper and board manufacturers for quality control and R&D.
- Printing houses and converters evaluating susceptibility to Z‑direction picking, blistering or interior delamination under rapid impacts.
- Packaging producers and laminators assessing bonded and multi‑ply products, coated sheets and film-laminated boards.
- Test laboratories and instrument manufacturers (Scott‑Bond style devices).
- Why it’s useful:
- Predicts performance under high‑rate impulses encountered during high‑speed printing, embossing, die‑cutting or automated conversion.
- Helps troubleshoot delamination issues, specify materials for robustness, and validate adhesive/laminate systems.
Related standards
- ISO 186 - Sampling to determine average quality (relevant for representative specimens)
- ISO 187 - Standard atmosphere for conditioning and testing
- EN 755‑2 - Aluminium alloy specification for platen material
Keywords: ISO 16260, internal bond strength, paper and board, Z-direction, pendulum test, Scott‑Bond, aluminium platen, adhesive tape, printing, converting, delamination.