Overview
ISO 4167:2006 - "Polyolefin agricultural twines" - sets the international requirements for simple yarns used in agricultural baling (baler twine) made from polyolefins (principally polypropylene (PP) and high‑density polyethylene (PE)). The standard defines the principal properties, sampling and laboratory test methods to verify those properties, designation and labelling, and the form of delivery (spools). It also includes handling recommendations (Annex A) and references related test atmospheres and twist designation standards.
Key Topics
- Scope and designation: How to designate a product (example: agricultural twine ISO 4167 - PP - 350, where 350 is nominal runnage in m/kg).
- Materials and manufacture: Polyolefin raw materials with adequate UV stabilization and non‑toxic pigments; twine must have a Z‑twist per ISO 2 and be wound/removed from the spool in a specified manner (centre, anti‑clockwise).
- Physical properties and limits:
- Linear density and runnage (m/kg) determined by weighing specified specimen lengths.
- Minimum twine breaking force is calculated from the nominal runnage using the formula given in the standard.
- Minimum average knot breaking force is specified as a proportion of the twine breaking force (the standard requires knot breaking force = 0.55 × twine breaking force).
- Nominal runnage tolerance: ±8% (rounded).
- Test methods:
- Linear density / runnage: weigh 30 m specimens; calculate tex and m/kg per clause 9.1.
- Tensile (breaking) tests: use a constant‑rate tensile machine, 10 specimens per spool, minimum grip spacing 250 mm, traverse speed equal to specimen length in mm/min ±10%.
- Knot test: thumb knot as illustrated in the standard; mean of 10 valid results.
- Sampling: Laboratory sample selection formula (S = 0.025 × N spools per batch up to 50 t) and random spool selection.
- Delivery & marking: Twine supplied on spools; marking and batch composition requirements included.
Applications and Users
- Manufacturers of baler twine and yarn producers use ISO 4167 to design and certify products for agricultural use.
- Testing laboratories and quality managers apply the specified sampling and test procedures to verify compliance.
- Agricultural equipment OEMs, distributors, and procurement officers rely on the standard when specifying twine for balers and automatic pick‑up machines to ensure safety and performance.
- Regulatory bodies and standards committees use ISO 4167 as a reference for product conformity and trade.
Related Standards
- ISO 2 (twist direction designation)
- ISO 139 (standard test atmosphere for conditioning)
- Prepared under collaboration between ISO/TC 38 and CEN/TC 248.
Keywords: ISO 4167, polyolefin agricultural twines, baler twine, runnage, linear density, knot breaking force, polypropylene, high‑density polyethylene, test methods, sampling, twine specification.