Standard Test Method for Peel Cling of Stretch Wrap Film

ASTM D5458 specifies a standardized peel‐cling test to quantify the adhesive interaction between two layers of stretch wrap film under both stretched and unstretched conditions. The method outlines detailed procedures for sample preparation, apparatus setup, test execution, and data analysis to ensure consistency and comparability of results across laboratories and suppliers. Key equipment includes a universal testing machine fitted with a specialized inclined‐plane cling fixture and a 500 g load cell to record peel forces at a constant grip separation rate.

مقدمة

Background of Stretch Wrap Film

Stretch wrap film—commonly fabricated from linear low‐density polyethylene—is used extensively to unitize and stabilize pallet loads by conforming tightly around products when tension is applied. The film’s inherent elasticity and cling properties enable multiple layers to adhere, forming a secure package that resists shifting during handling and transit.

Importance of Cling in Packaging

Cling strength is critical for maintaining load integrity, as insufficient adhesion can lead to layer slippage, compromised stability, and potential product damage during shipping. By quantifying the peel force, manufacturers and end‐users can select films that deliver consistent performance, optimize material usage, and reduce waste.

Scope and Significance of ASTM D5458

Scope of the Standard

ASTM D5458 applies to stretch wrap films in both stretched and unstretched states and provides procedures to determine the force required to peel a 1 in. (25 mm) film strip from a flat film surface. Results are reported in inch‐pound units (with SI conversions provided for information) and serve as a benchmark for product comparison.

Significance and Use

This Stretch Film Peeling Cling طريقة الاختبار enables quality control labs to verify that films meet cling performance specifications, supporting reliable load‐securing operations in warehousing and distribution. It also guides R&D efforts in film formulation by linking material properties—such as resin type, additives, and thickness—to measurable cling behavior.

Test Procedure

تحضير العينة

Film specimens include a large “base” sample affixed to the inclined fixture and smaller 1 in. × 5 in. strips mounted on clips. Conditioning of films (e.g., temperature and humidity) follows Practice D4332 to minimize environmental influences on cling measurements.

Equipment and Setup

A universal testing machine with a constant‐rate grip separation and a 500 g load cell is required, along with:

– Lightweight rubber‐faced grips (1 × 1.5 in.) .

– Cling attachment and clamp fixtures (see ASTM figures).

– Precision sample cutter and separation paper for clean edges.

إجراءات الاختبار

Clamp the base film on the incline (outside face up) and secure the free end with a steel rod to apply desired pre‐stretch. Place the film strip onto the inclined surface, apply uniform pressure to establish contact, then attach the strip’s free end to the testing machine’s clip. Initiate grip separation at the standard rate (e.g., 12 in./min) and record the peak force when the strip peels from the base.

Calculation of Cling Strength

The cling strength is defined as the maximum peel force per unit width (e.g., N/25 mm or lb/in.). Multiple replicates (minimum of five) are tested to calculate an average and assess variability.

Precision and Reproducibility

Interlaboratory studies (e.g., Practice E691) underpin the standard’s precision statements, indicating typical repeatability and reproducibility bounds for cling measurements. Users should refer to the precision tables in the official ASTM document to interpret measurement uncertainty.

Practical Considerations and Tips

Ensure film surfaces are free of dust, oils, or static charges that can skew cling results. Calibrate the testing machine regularly and verify load cell accuracy to maintain data integrity. When comparing films, maintain consistent environmental conditions and sample orientation.

الخاتمة

ASTM D5458 provides a robust, reproducible method for evaluating the peel‐cling performance of stretch wrap films, facilitating quality control and product development across the packaging industry. By following the standardized procedure and accounting for precision metrics, manufacturers and end users can reliably assess film adhesion, optimize materials, and ensure secure load stability.

For further technical guidance or to source calibrated cling‐testing equipment, please contact us; as your trusted supplier, Cell Instruments deliver comprehensive testing solutions tailored to your stretch wrap performance requirements.