How Do You Measure the Tearing Strength of Paper?

One widely recognized method of measuring the tear strength of paper is the Elmendorf tear test, which provides a standardized way to quantify how well paper withstands tearing forces. The test gets its name of the inventor, Armin Elmendorf. 

Thwing-Albert Instrument Company offers a wide range of Elmendorf tear testing equipment — specializing in precision testing machines used to measure the physical properties of materials. The test uses the propagation of tear by a pendulum.

Thwing-Albert actively engages with major standardization organizations, such as the International Organization for Standardization (ISO), the American Society for Testing and Materials (ASTM), as well as the Technical Association of the Pulp and Paper Industry (TAPPI).

How Is Tear Resistance Measured?

The test involves several vital steps to ensure accurate tear strength results:

1. Sample preparation: The first step in the test is to prepare the samples using the Elmendorf tear sample cutter. Cut the samples into rectangular shapes using the specified dimensions. 
2. Instrument setup: Configure the instrument with a pendulum of adequate capacity and secure the test specimen in the clamps. 
3. Testing procedure: The test begins by making the initial cut in the specimen, creating the required initial tear. The pendulum is released from the starting position and swings through to tear the specimen along the pre-cut slit. It is recommended to test the material in the machine direction (MD), meaning the direction of the paper web during paper making, and cross direction (CD).
4. Recording results: The force required to propagate the tear through the specimen gets recorded in grams-force (gF), newtons (N), or percentage of pendulum capacity used. This force recorded indicates the tear strength of the paper. 

What Size Sample for Elmendorf Tear Tester?

One common sample is a 63mm x 76mm rectangle. For material that does not tear in a straight line, the use of a constant radius specimen is recommended.

Importance of the Elmendorf Tear Test

The tearing strength measured by the test is crucial for:

• Quality control: Manufacturers use these tests to ensure their paper products meet specified tearing strength requirements, ensuring quality and reliability. 
• Product development: Researchers and developers use the test to develop new paper products or enhance exisiting ones oto better meet the market demands.
• Regulatory compliance: Many industries have standards for tearing strength, each with its own set of requirements and specifications. 

Choose Thwing-Albert Elmendorf Test Testing Equipment Today

Contact us today for a free quote or to learn more about the benefits of our equipment. Thwing-Albert has over 120 years of experience manufacturing and designing equipment for measuring tear resistance.