ASTM D689

Application Materials

ASTM D689 specifies the standard test method for determining the tear strength of paper and paperboard. This test is essential for evaluating the quality and durability of materials used in packaging, printing, and other applications where paper strength is critical.

Test Process

The test involves using a tear tester for paper, such as the Elmendorf-type tear tester. A sample of the paper or paperboard is prepared, with a specific notch cut into it. The sample is then clamped into the tester, and the instrument applies a controlled force to propagate the tear through the material. The force required to complete the tear is recorded.

Test Result Interpretation

The test result is expressed in terms of the tearing resistance of the paper, usually in grams-force (gf). Higher values indicate greater resistance to tearing, implying a stronger and more durable material. These results help manufacturers and quality control professionals assess the material’s suitability for its intended use.

Test Significance

The tear strength test is significant because it provides a quantitative measure of the paper’s durability and performance under stress. This information is vital for ensuring that paper products meet specific quality standards and can withstand handling and processing without failure.

Instrument Requirements

The primary instrument used in this test is the tear tester for paper, which must be calibrated and maintained according to the manufacturer’s specifications. The instrument should provide accurate and repeatable results, with a reliable method for clamping and tearing the sample.

Precautions

Ensure the sample is prepared according to the standard dimensions and notching requirements.

1. Verify that the tear tester is properly calibrated before conducting the test.
2. Handle the paper samples carefully to avoid pre-test damage that could affect the results.
3. Follow all safety protocols to prevent injuries while using the tear tester.

Reference

ASTM D689-17 Standard Test Method for Internal Tearing Resistance of Paper