DIN 53362 Determination of Bending Stiffness of Plastic Films and Textile Fabrics - According to the Cantilever Method

The standard “DIN 53362 Testing of plastic films and textile fabrics (excluding nonwoven fabrics), coated or uncoated plastics - Determination of bending stiffness - According to the cantilever method”, published by the German Institute for Standardization (DIN), describes a test method for measuring the bending rigidity (bending stiffness) of thin, flexible materials. This standard is particularly applicable to:

• plastic films
• Woven textile fabrics
• Textile fabrics with or without plastic coating.

However, this standard does not cover nonwoven fabrics, for which the EN ISO 9073-7 standard generally applies.

This test method is a cantilever-based method very similar in principle to ASTM D1388 or BS 3356 standards. It utilizes the classic cantilever principle. Accordingly, a strip-shaped specimen (typically 25 mm wide and 200 mm long, but dimensions may vary slightly depending on the material) is placed on a horizontal platform with a marked scale. One end is fixed while the free end hangs outwards. The specimen is slowly advanced until its leading edge bends under its own weight and touches a reference line or angle (typically when the end reaches 41,5 degrees from the horizontal, this is a standard critical angle in cantilever stiffness tests). The sag length at this point is measured in millimeters. From this length, the bending stiffness (bending rigidity) is calculated. Some devices directly provide the bending length, bending rigidity, or modulus of flexure.

The main features of this standard are:

• Simple, low-cost equipment: An inclined plane or horizontal platform + a scaled fabric stiffness tester is sufficient (many commercial models conform to the DIN 53362 standard).
• Directionality: Since woven fabrics are anisotropic, tests are usually performed in the warp/weft directions (and sometimes the cross direction).
• Typical materials tested include: technical textiles, air cushion fabrics, coated fabrics, plastic sheets, tarpaulins, laminated materials, and similar items.

This standard remains important in quality control for textiles, technical fabrics, packaging films and coated materials where tactile feel, drape or resistance to bending is an important performance characteristic.

Other standards related to this standard are as follows:

• ASTM D1388 Standard test method for stiffness of fabrics (includes similar cantilever method)
• EN ISO 9073-7 Nonwoven fabrics - Test methods - Part 7: Determination of twist length (applicable to nonwoven fabrics)
• DIN 53350 Plastic films and sheets - Determination of rigidity in bending - Two-point method (Ohlsen approach) (includes two-point method for films)

In short, the DIN 53362 standard defines a method used to determine the bending stiffness (flexural rigidity) of plastic films, sheets, coated fabrics, and textile materials. This test evaluates how resistant a material is to bending when subjected to its own weight under controlled conditions.

This standard is widely applied in industries such as textiles, synthetic leather, packaging films, and automotive interior materials, where flexibility and drape properties are critical to product performance and use.

The main purpose of the DIN 53362 standard is to provide a consistent and repeatable method for measuring the stiffness of thin, flexible materials. Bending stiffness is affected by:

• The drape and feel of the fabrics.
• Usage characteristics of plastic films
• Comfort and flexibility of coated textiles.
• Processability in production

For example, materials used in automotive upholstery, seat covers, and synthetic leather must strike a balance between flexibility and structural integrity, making stiffness testing crucial.

The cantilever method used to determine bending stiffness generally follows these steps:

• Samples are typically conditioned under standard laboratory climate conditions prior to testing to ensure reproducibility.
• A rectangular test specimen is placed on a horizontal platform.
• The sample is gradually pushed forward so that one end hangs over the edge of the platform.
• The sample is allowed to bend under its own weight.
• When the bending angle reaches the specified value, the protrusion length is recorded.
• Measurements for textile materials can be taken in both longitudinal and transverse directions.
• The measurement is repeated several times and an average is calculated.
• The greater the length the sample must stretch before bending, the more rigid the material becomes.

Bending stiffness is calculated using the bending length obtained from the overhang measurement. The result is usually expressed as follows:

• Bending length
• Bending rigidity

Bending rigidity depends on the following:

• Material weight per unit area
• Bending length

Higher values ​​indicate harder materials, while lower values ​​indicate more flexible materials.

This standard requires the following equipment:

• Cantilever rigidity testing machine
• Horizontal support platform
• Sliding sample holder
• Angle indicator or optical scale
• Deviation length measurement scale

This equipment enables precise measurement of bending length.

Typical sample requirements include:

• Rectangular strips
• Uniform thickness
• Smooth edges

Typical dimensions (may vary depending on material):

• Width: Approximately 20-30 mm
• Length: Approximately 150-200 mm

The DIN 53362 standard is used in various sectors:

• Textile industry:
• Evaluation of fabric drape and texture.
• Quality control for clothing and upholstery fabrics.
• Plastics industry:
• Testing of plastic films and sheets.
• Evaluating the flexibility of packaging materials.
• Automotive industry:
• Testing coated fabrics
• Evaluation of synthetic leather for seats and upholstery.
• Artificial leather production:
• Determining the softness and flexibility of materials used in upholstery and footwear.

Using the DIN 53362 standard offers several advantages:

• Consistent testing procedures
• Reliable comparison of materials.
• Improved product quality control.
• Better prediction of end-use performance.

Manufacturers rely on this testing to ensure materials meet functional and comfort requirements before being used in final products.

In conclusion, the DIN 53362 standard specifies a cantilever-based test method for determining the bending stiffness of plastic films and textile fabrics. By measuring how much a material can stretch before bending under its own weight, the test provides valuable information about the material's flexibility, drape, and mechanical behavior.

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 53362 standard.