Evaluate the Adhesion Strength of Your Films with Our Peel Cling Test

Ensure your stretch films and food wrap films meet the required cling force standards. Our Peel Cling Test accurately measures how well your films adhere to surfaces, guaranteeing high performance in packaging applications. Trust Cell Instruments for reliable, standard-compliant testing solutions.

Cling Peel Test System

Why Wrap Films (Stretch & Food Wrap Films) Have Cling Features

 

The Cling Feature of Wrap Films

The cling feature of stretch films and food wrap films is one of the most critical properties in ensuring effective product packaging, protection, and preservation. 

This ability to cling or adhere to surfaces is vital for both stretch films (used in logistics and packaging) and food wrap films (used for food preservation).

 

How the Cling Feature is Created

Cling is primarily a result of electrostatic charges and adhesive properties built into the film’s surface. For stretch films, cling is created during the manufacturing process, where specific polymers are used to impart the film’s ability to stretch and adhere to itself and other surfaces.

For food wrap films, cling is typically achieved through polyethylene or polyvinyl chloride (PVC), which are known for their tacky or sticky surfaces.

stretch film application test

Stretch Films: The molecular structure of stretch films is designed to allow them to stretch and cling tightly to products. The polyethylene resin, when stretched, enhances its adhesive qualities, forming a secure, tight bond without the need for additional adhesives.

Food wrap film application test

Food Wrap Films: These are generally produced with a higher percentage of tacky materials (such as PVC), which provide strong cling to smooth, non-porous surfaces, ensuring products are securely wrapped for freshness and protection.

Understanding and testing the cling strength of these films is crucial to ensure the films provide adequate protection and meet packaging standards.

Peel Cling testing is governed by a variety of international standards to ensure consistency and reliability across the film testing industry. The key standards for Peel Cling are ASTM D5458 and BB/T 0024.

ASTM D5458 BB/T 0024

ASTM D5458 – This standard outlines the methodology for measuring the peel cling force of stretch films. It is widely adopted by manufacturers and testers globally.

BB/T 0024 is a Chinese standard for stretch wrap film for transportation packaging, applicable to stretch wrap film produced from polyolefin plastic as the main raw material and used for transportation packaging not in direct contact with food.

These standards provide clear guidelines on how to prepare samples, the required testing conditions, and the acceptable limits for cling strength to meet quality and performance expectations.

Test Overview

The Peel Cling Test measures the force required to peel a stretch film or food wrap film from its outer outer layer, i.e., the separation force between its one inner surface and its outer. This test simulates the cling strength the film will exhibit when used in packaging or preservation applications.

Step-by-Step Test Procedure

1.Prepare the Sample

  • Remove at least three outer wraps from the roll before selecting the sample.
  • Using the precision sample cutter, cut a one inch (25.4mm)transverse direction (TD)by approximately 7 in.(180 mm)machine direction (MD) specimen from each paper/film/paper sandwich. These will be used with the corresponding 5 by 20 inch (125 by 500 mm) samples.
  • Using the sample template and razor blade, cut three 5 by 7 inch(125 by 180 mm) TD by MD samples corresponding to the TD locations of the 1 by 7 inch(25.4 by 180 mm) samples cut above.

2.Tester Preparation

Instrument Calibration: The SPC-01 Peel Cling Tester is calibrated before test to ensure accuracy(A yearly calibration frequency is applicable).

Temperature & Humidity Control: Ensure the testing environment is within recommended conditions (usually 23°C and 50% humidity) to minimize environmental influences.

3.Sample Loading

Place a 5 by 20 in.(127 by 508 mm) sample squarely on the incline face with its outside surface up.

Grasp the unclamped corners of the film sample and pull back over the incline face to create a tight, smooth surface of film. In accordance with the desired stretch percentage,measure down the incline face from the top and mark both edges of the film sample. The appropriate distances are as follows: 

Desired Elongation %

0
50 
100 
200

Distance Down incline Face, in.(mm)

0 (0)
2 (50)
3 (75)
4 (100)

 

Roll the free end of the film up on the steel rod to within l inch(25 mm)of the marks on the film.

Elongate the sample, using the steel rod as the grip area, until the marks are aligned with the top edge of the incline.

While still holding the film tightly enough to maintain this extension, move the rod down and through the clamps and clamp the film, Some film might have to be allowed to unwind from the rod during this step to ensure proper mark positions and yet have film to clamp.

 

4.Upper Sample Loading

Place the 25.4mm sample on the incline film sample and at the top of the incline. The sample is aligned so that the remainder of the sample will lie between the parallel guide lines that run the full face length of the incline.

After sample is positioned, brush the sample with moderate pressure with three strokes, to eliminate air and ensure good contact between the samples.

 

5.Clamp Upper Sample and Start The Test

The lower end of the upper sample is rolled and inserted in the film clip. Start the tester and the sample is separating from the incline. The vale at the horizontal cling line is treated as the cling force.   

Cling Force Wrap Film Measured

FAQs about Peel Cling Test

What is the Protrusion Puncture Test for Wrap Films?

The Protrusion Puncture Test evaluates the puncture resistance of wrap films by simulating a real-world scenario where the film is subjected to puncturing forces. The test involves applying a specific force to the film’s surface using a protruding object to measure how much force the film can withstand before it punctures or tears. This test helps assess the durability of the film during handling, transportation, and storage.

 

What Are the Key Applications of the Protrusion Puncture Test in the Packaging Industry?

The test is widely used in the flexible packaging and wrap film industries to evaluate the strength and resistance of films used for food packaging, industrial wrapping, medical packaging, and more. It helps determine the film’s ability to resist punctures caused by sharp objects, mishandling, or external pressure, making it crucial for ensuring product integrity during transit and storage.

 

Why is the Protrusion Puncture Test Significant for Wrap Films?

The significance of this test lies in its ability to predict how the film will behave under real-world conditions where punctures are a risk, such as during transportation or in situations involving sharp objects. A high puncture resistance is crucial for packaging films, as it can prevent damage to the product inside, reduce waste, and ensure that the packaging meets the required safety standards. The test is a good indicator of film durability and its ability to protect the contents.

 

What Are the Common Factors That Influence the Results of the Protrusion Puncture Test?

Several factors can influence the results of the puncture test, including:

  • Film thickness: Thicker films tend to have higher puncture resistance.
  • Material composition: The type of polymer (e.g., polyethylene, polypropylene) impacts puncture strength.
  • Film orientation: The machine direction (MD) and transverse direction (TD) may show different puncture resistance values.
  • Environmental conditions: Temperature and humidity during testing can affect the film’s flexibility and strength. Understanding these factors ensures accurate and reliable results for evaluating the performance of wrap films under different conditions.

More Tests For Wrap Film