ASTM D1004 is a test method that determines the tear strength of flexible plastic film and sheeting at very low rates of loading using a constant-rate-of crosshead-movement type tensile testing machine. Tearing is produced in a small area of stress concentration of the plastic film or sheeting specimen at controlled speeds below the rate encountered in real world applications in order to produce the most reliable data, which can be used to compare and analyze the tear resistance. Actual use of performance in tearing of certain plastics may not necessarily corralate with the data acquired from this test method. 

Scope:

Tear resistance measures the ultimate force required to tear film or sheet. It is often used for quality control checks or for material comparison where tear failures are possible.

Test Procedure:

The average thickness of the specimen is measured. The specimen is then placed in the grips of the testing machine and pulled at a rate of 2 in. per minute until rupture.

Specimen Size:

The specimen is die cut to the appropriate shape from a sheet. The shape of the specimen is designed to create a tear when the specimen is pulled in tension. Die C specimens are commonly used.