Overview
ISO/TS 23927:2024 - "Laminates and moulding compounds - Prepregs - Determination of tack" is a Technical Specification that defines a reproducible, quantitative test method for measuring the tack of thermoset-based prepregs (unidirectional and multidirectional) made with glass, carbon, aramid and similar reinforcement fibres. Published in 2024, it provides apparatus, specimen, conditioning and procedural requirements to obtain consistent tack measurements suitable for quality control and automated production.
Key Topics and Requirements
- Definition of tack: Tack is the maximum retracting (separation) areal force measured when a defined probe is pulled away from the prepreg surface; expressed in Newtons (N).
- Apparatus:
- Probe: 304 stainless steel, 80 mm diameter, flat end machined at 90°, surface roughness ≤ 500 nm (≤ 250 nm RMS per ISO 21920-2), hardness ≥ 80 HRB; self-aligning probe recommended.
- Support platen: same material as probe, at least 1.5× specimen size (≥ 100 × 100 mm), flatness deviation ≤ 0.01 mm over 100 mm.
- Force measurement system: inertia-free, compliant with Class 1 of ISO 7500-1.
- Tension/compression testing machine: meet ISO 7500-1 requirements; data acquisition frequency sufficient for accurate force/time capture.
- Specimens and conditioning:
- Specimen size: 100 × 100 mm (±2 mm).
- Minimum five specimens from the same roll; more can be used for precision (95% confidence per ISO 2602).
- Condition per ISO 291; preferred atmosphere (23 ± 2) °C and (50 ± 10) % RH; conditioning time ≥ 4 h (or as agreed).
- Test cycle (compression/dwell/retraction):
- Compress to (900 ± 10) N at 1 mm/min.
- Hold compression for (100 ± 1) s (dwell).
- Retract at 25 mm/min and record force–time curve; maximum retracting force = tack.
- Specimen seating and cleanliness: use thin-film double-sided tape or equivalent; probe cleaned with a solvent that leaves no residue; protective film handling guidance included.
Applications and Users
- Practical use cases:
- Quality control of prepreg batches.
- Process control for automated layup, AFP/ATL, and automated manufacturing where tack affects placement and consolidation.
- R&D and material comparison for composite suppliers and OEMs (aerospace, automotive, wind energy, sporting goods).
- Typical users:
- Test laboratories, composite material suppliers, manufacturing engineers, and QA/QC teams involved in prepreg handling and assembly.
Related Standards
- ISO 291 - Standard atmospheres for conditioning and testing
- ISO 7500-1:2018 - Verification of static uniaxial testing machines (force measurement)
- ISO 21920-2 - Surface texture: profile method (surface roughness parameters)
ISO/TS 23927:2024 delivers a standardized, quantitative tack test that improves repeatability and supports both manual and automated prepreg manufacturing workflows.