Overview
EN ISO 17708:2018 - "Footwear - Test methods for whole shoe - Upper sole adhesion" is a CEN-endorsed ISO standard that specifies a laboratory test method to measure the resistance to separation between the upper and outsole of finished footwear. The standard covers the force required to separate the upper from the sole, to delaminate adjacent outsole layers, or to cause tear failure of the upper or sole. It also defines conditioning and ageing options for production control. EN ISO 17708:2018 applies to all closed shoe constructions (cemented, vulcanized, injection‑moulded, etc.) where evaluation of sole adhesion is required, but not to assemblies fastened by grindery (nails/screws) or stitching.
Key topics and technical requirements
- Test objective: Measure bond strength nearest the edge of the assembly (upper–sole interface).
- Applicable constructions: Types a–g (conventional lasting, cemented, injected/vulcanized, strobel, welted, multilayer soles) - specific sample preparation differs by type.
- Sampling & conditioning: Footwear must be conditioned according to ISO 18454 for at least 24 hours; allow 72 hours for freshly glued parts when taken directly from production. Optional ageing processes for production control are defined in Annex A. Minimum two items per model.
- Apparatus & measurement: Sharp cutting device; tensile testing machine meeting ISO 7500-1 (force range 0–600 N, low‑inertia, autographic recording); jaws 25–30 mm wide; measuring device with ±0.5 mm accuracy for test‑piece width.
- Test procedure: Cut and, where required, pre‑separate the upper/sole layers (hot knife). Measure width at five points and compute average. Pull in tensile machine at a separation speed of 100 mm/min (tolerance specified in the standard) while recording force/deformation.
- Results & interpretation: Report force per unit width (upper‑sole adhesion), evaluate and classify the mode of bond failure (adhesive separation, cohesive failure, tear, interlayer delamination) and include conditioning/ageing details.
Applications and who uses it
- Footwear manufacturers - production control, incoming/outgoing inspection, process validation (cementing, moulding, vulcanization).
- Quality assurance and R&D teams - compare adhesives, sole materials, and construction methods; verify durability after ageing.
- Third‑party test laboratories and certification bodies - standardized method for supplier verification and compliance testing.
- Procurement and footwear designers - confirm design choices meet adhesion performance requirements.
Related standards
- ISO 18454 - standard atmospheres for conditioning and testing of footwear
- ISO 7500-1 - calibration and verification of tensile testing machines
- EN 344 - earlier basis for this revision
Keywords: EN ISO 17708:2018, upper‑sole adhesion, footwear test methods, bond strength test, sole adhesion testing, tensile testing machine, footwear conditioning, production control.
