ISO 20299-2:2024

Overview

ISO 20299-2:2024 specifies material and physical property requirements for non‑strippable low‑density polyethylene (LDPE) film used to wrap natural rubber and modified natural rubber bales. Intended to keep bales separate during transport and storage, the standard covers block natural rubber, ribbed smoked sheets, and modified natural rubbers (e.g., ENR, LPNR) in common bale masses (33,3 kg / 33.3 kg, 35 kg and selected larger formats by agreement). This third edition (2024) updates test methods and extends the scope to modified natural rubber.

Key topics and requirements

• Material
  • Film shall be manufactured from LDPE (non‑strippable).
  • Slip agents, antioxidants and anti‑blocking agents are normally not included (note).
• Thickness
  • Measured with a micrometer: 0.03 mm to 0.05 mm.
• Density
  • (0.92 ± 0.01) g/cm³, determined by method A of ISO 1183‑1:2019.
• Thermal properties (meet at least one option)
  • Vicat softening temperature ≤ 95 °C, tested per ISO 306:2022 (method A50).
    • Note: Vicat is typically ~18 °C lower than DSC peak melting.
  • DSC peak melting temperature ≤ 113 °C, per ISO 11357‑3.
  • Capillary‑tube melting temperature ≤ 113 °C, per method A of ISO 3146:2022.
• Marking
  • Marking details (location, colour, size) are to be agreed between parties.
• Test report
  • Must reference ISO 20299‑2:2024 and include sample identification, unusual observations, clause 5 test results and test date.

Applications and who uses this standard

• Rubber producers and processors: ensure wrapped bales disperse film in internal mixers (mixing temperatures typically 120–160 °C) to avoid contamination and extra stripping steps.
• LDPE film manufacturers: design and certify bale‑wrapping film to meet thickness, density and thermal criteria.
• Quality laboratories and inspection bodies: perform specified tests (Vicat, DSC, capillary method, density) and issue compliant test reports.
• Buyers, exporters and logistics providers: specify accepted wrapping film properties in procurement and contracts to reduce ash, fungal growth and handling costs.
• Environmental and process engineers: reduce reliance on bale coating solutions by switching to dispersible LDPE wrapping.

Related standards

Normative test methods referenced:

• ISO 306:2022 - Vicat softening temperature (VST)
• ISO 1183‑1:2019 - Density of plastics (method A)
• ISO 3146:2022 - Capillary tube melting temperature (method A)
• ISO 11357‑3 - Differential scanning calorimetry (DSC) - peak melting

Keywords: ISO 20299‑2, LDPE film, rubber bale wrapping standard, natural rubber packaging, Vicat softening temperature, melting point, density, bale wrapping film.