DIN 53363 Determining the Tear Resistance of Plastic Films and Sheets by the Trouser Tear Test Method

The German Standards Institute (DIN) standard, “DIN 53363 Determination of tear resistance of plastic films and sheets by the trouser tear method,” describes a test method for determining the resistance of plastic film to tear propagation under specified conditions. This method is applicable to products that, due to their softness, do not break when clamped between the holders of a tensile testing machine. The test procedure allows for the comparison of samples taken from different products, provided that the sample thicknesses do not differ by more than 10 percent.

This standard is particularly important in material testing of flexible plastics, such as packaging films, tarpaulins, artificial leather substrates, and other thin polymer sheets where tear resistance is a critical performance characteristic.

According to the DIN 53363 standard, the primary purpose of the test is to measure how much force a plastic film can withstand under controlled conditions before tearing propagation occurs. This method is particularly helpful in evaluating the durability of materials in applications where films may be subjected to stress that causes cutting, puncturing, or tearing (e.g., packaging, agricultural films, or technical textiles).

This method is suitable for the following:

Flexible plastic films and sheets that do not tear easily under normal use.
Comparing samples of similar thickness (for reliable comparisons, differences should generally not exceed 10 percent).
It is not designed for rigid plastics, thick sheets (at least 1 mm in some contexts), cellular materials, or heavily reinforced composites.

This standard defines the test for trouser tearing with a pre-cut (single tear test) or the trapezoidal tear test. This test essentially follows these steps:

Sample preparation: A trapezoidal or rectangular sample is cut from the film. A controlled cut (slit) is made in the middle or at one end to initiate the tearing process.
Assembly: The two legs of the sample (resulting from the cut) are clamped into a tensile testing machine, much like separating the legs of a pair of trousers (hence the name "trouser rip" method).
Test: The machine applies a constant tearing speed until the tear spreads along a specific length. The force required to spread the tear is recorded.
Results: Tear strength is typically expressed in Newtons (N) or Newtons per unit thickness/length. Multiple samples (usually in the machine direction and transverse direction) are tested to account for anisotropy in extruded or blown films.

The basic parameters are as follows:

Test speed (usually constant).
Sample conditioning (temperature and humidity).
Number of tests required for statistical reliability.

This method differs from tensile strength tests (for example, the DIN EN ISO 527 series of standards which measure elongation and fracture strength without prior shearing).

The DIN 53363 standard test method is compatible with international equivalent standards such as “ISO 34-1 Rubber, vulcanized or thermoplastic - Determination of tear strength - Part 1: Trousers, gussets and crescent test pieces”, which includes the trouser tear method for rubber/plastics, and “ASTM D1813 Standard test method for measuring the thickness of leather specimens”, which includes the trouser tear method for thin films. However, the DIN 53363 standard is still used as a reference, particularly in European industries, in product specifications, test reports, and legacy technical documentation.

Plastic film manufacturers (e.g., PE, PP, PVC films) use this test for the following purposes:

Ensuring product quality for packaging or protective covers.
In sectors such as food packaging, agriculture, or construction, they meet customer specifications (for example, tarpaulins often have tear strength specified according to the DIN 53363 standard).
Comparing material formulations or suppliers.

In short, tear strength is a crucial mechanical property that indicates how well a material can resist the propagation of a tear once it has begun. This test is widely used in industries such as packaging, automotive interiors, construction membranes, and technical films, where thin plastic materials need to maintain their structural integrity under stress. The primary aim of the DIN 53363 standard is to provide a reliable and repeatable method for measuring the force required to sustain a tear after the initial cut or notch is created in a plastic film.

Understanding tear resistance helps manufacturers in the following areas:

Evaluating material durability.
Comparing different film formulations
Checking production quality
Predicting performance during transport and use.

The materials typically subjected to this test include:

Polyethylene (PE) films
Polypropylene (PP) films
PVC films
Laminated plastic sheets
Packaging films

The DIN 53363 method measures the force required to expand an existing tear in a specimen. The basic principle is as follows:

Samples are conditioned under standard laboratory conditions (temperature and humidity).
A rectangular test specimen is prepared.
A specific notch or slit is made along one edge of the sample. The pre-cut notch serves as the starting point for tear propagation.
The sample is mounted on a tensile testing machine.
The machine separates the samples at a constant crosshead speed.
The force required to widen the tear (tear propagation force) is continuously recorded.
The resulting force reflects the tear resistance of the material.

When evaluating the results, the average tear strength is calculated. The force required to propagate the tear is reported as tear resistance. Sometimes the result is normalized according to thickness or width.

Equipment used in the tests includes:

Universal tensile testing machine
Special clamps or holders designed for thin films.
Cutting device for preparing standardized samples.
A notching tool to create the initial tear.
Measurement system for recording force.

Samples are generally tested in two ways:

Machine direction: Along the direction of film production.
Transverse direction: Perpendicular to the direction of production.

This helps to evaluate the anisotropy common in plastic films.

The DIN 53363 standard is particularly useful for evaluating thin plastic films used in demanding applications. Its main industrial benefits include:

Evaluation of packaging durability.
Quality control in film production.
Comparison of different polymer formulations
Estimating damage resistance during transportation.

For example, in packaging, higher tear resistance means the film is less likely to tear during handling or shipping.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services in accordance with the DIN 53363 standard.