DIN 53377 Testing of Plastic Films - Determination of Dimensional Stability

The standard “DIN 53377 Testing of plastic films - Determination of dimensional stability”, published by the German Institute for Standardization (DIN), describes a method for determining dimensional changes in plastic films that may result from various processes, such as heat treatment. This standard defines a standardized test method for measuring dimensional changes (dimensional stability or shrinkage) in plastic films and thin sheets.

This standard is widely used in the plastics industry, particularly for flexible packaging materials, label films, decorative films, shrink films, and other polymer-based films where dimensional changes due to heat or other processes can affect performance, print registration, or converting processes.

Plastic films often exhibit dimensional instability when exposed to heat (e.g., after drying following printing, heat sealing, thermoforming, or storage under hot conditions). These changes can be shrinkage (negative) or, less commonly, expansion. The DIN 53377 standard provides a repeatable method for measuring linear dimensional changes in the machine direction and transverse direction after controlled thermal exposure or other specified processes.

This testing method works by measuring the dimensional change of a film sample before and after exposure to heat. The method generally follows these steps:

• Sample preparation: Rectangular test specimens are cut from film and reference marks or measurement lengths are placed on the specimen. Typically, with precise marks or reference points/lines at known distances, e.g., 100 mm or 200 mm intervals.
• Conditioning: Samples are generally pre-conditioned under standard climatic conditions. For this purpose, the sample is placed in a controlled heating environment (usually an oven). After heating for a specified time, the sample is removed and cooled.
• Processing/exposure: The most common procedure involves applying heat treatment in a furnace or heating chamber. Typical conditions include:
• Temperatures range from approximately 80 degrees to 175 degrees (depending on the material; lower for heat-sensitive films like PVC, higher for PET or PP).
• Common exposure times: 10 minutes, 15 minutes, etc.
• Measurement: After cooling to room temperature, the distance between the reference marks is measured again (manually with calipers or optically).
• Calculation: Dimensional change is expressed as a percentage. A negative value indicates shrinkage (the most common result), while a positive value indicates expansion. The result indicates the dimensional stability or shrinkage behavior of the film.
• Reporting: Results are given separately for the machine direction and the transverse direction, usually with tolerances (e.g., maximum allowable shrinkage of 5 to 10 percent for specific applications).

Typical equipment required for testing includes:

• Temperature-controlled oven
• Precision measuring instrument (caliper or measuring microscope)
• Marking tools for measurement points
• Flat support frame or holder for samples.
• Conditioning chamber for pre-test stabilization.

Consistent temperature and sample positioning are crucial for reliable results.

The DIN 53377 standard is widely used in industries that rely on heat-resistant film materials, including the following:

• Thermally insulated packaging
• Automotive interior films
• Decorative and laminated films
• Electrical insulation films
• Biaxially oriented films
• Shrink films (PVC, PETG, polyolefin)
• Label and packaging films (e.g., checking heat stability after printing)

Manufacturers use this testing method to ensure that films will maintain their dimensional accuracy during processing or use.

Many technical data sheets for plastic films list dimensional stability or shrinkage values ​​according to the DIN 53377 standard as follows:

• Longitudinal (machine direction): 6 to 10 percent
• Transverse (in the transverse direction): 2 percent to 0 percent

The DIN 53377 standard shows similarities to the following standards:

• The standard “ASTM D1204 Standard test method for linear dimensional changes of rigid thermoplastic sheets or films at high temperatures” is frequently compared or used interchangeably in international trade.
• The “ISO 14616 Heat-shrinkable films - Determination of shrinkage” standard focuses primarily on shrink films.

This testing method is critical for quality control in film production and helps ensure that films maintain their dimensions in subsequent processing.

In short, the DIM 53377 standard includes a method for determining the dimensional stability of plastic films when exposed to high temperatures. This test evaluates how much the plastic film shrinks or expands after being exposed to controlled heating conditions.

Dimensional stability is a critical property for films used in packaging, automotive components, laminates, insulation materials, and technical textiles. Maintaining the original size and shape under varying temperatures is essential.

The primary purpose of the DIN 53377 standard is to measure the thermal shrinkage or expansion behavior of plastic films. Many polymer films undergo dimensional changes when heated due to internal stresses generated during processing (such as extrusion or stretching). This standard helps manufacturers in the following areas:

• To evaluate the thermal stability of plastic films.
• Detecting residual voltages resulting from production.
• Ensuring product performance during heat exposure.
• Comparing materials for quality control and product development.

Dimensional stability testing is crucial because excessive shrinkage can lead to:

• Wrinkling of films
• Misalignment in laminates
• Packaging defects
• Poor fit in engineering components.

By implementing the DIN 53377 standard, manufacturers can detect these problems early and maintain consistent material performance and product reliability.

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 53377 standard.