ASTM D1709

Application Materials

ASTM D1709 is used to assess the impact resistance of plastic films, which are commonly used in packaging, agriculture, construction, and various consumer products. These materials include polyethylene, polypropylene, and other flexible plastic films.

Test Process

1. Sample Preparation: Plastic film samples are prepared according to the specified dimensions and conditioning requirements.
2. Dart Selection: A hemispherical dart (tup) is selected based on the expected impact resistance of the film.
3. Testing Apparatus: The dart is dropped from a specified height onto the film sample clamped over a circular opening.
4. Impact Test: The dart is released to fall freely onto the film. The test can be performed using two methods:
   • Method A: The dart (diameter = 38±1mm) is dropped from a height of 660mm.
   • Method B: The dart (diameter = 50±1mm) is dropped from a height of 1500mm.
5. Observation: The test is conducted until a failure point is reached, where the film ruptures due to the impact.

Test Result Interpretation

• Failure Point: The result is recorded as the weight of the dart at which 50% of the samples fail (break or puncture). This is often referred to as the “impact failure weight” or “dart drop impact strength.”
• Statistical Analysis: The results can be statistically analyzed to determine the mean and standard deviation of the failure points, providing a measure of the film’s impact resistance.

Test Significance

• Material Performance: The test determines the ability of plastic films to withstand impact forces, which is crucial for applications where the films are subjected to rough handling or mechanical stress.
• Quality Control: The results help manufacturers ensure consistent quality and performance of plastic films.
• Product Development: The test aids in the development of new films with improved impact resistance properties.

Instrument Requirements

• Dart Assembly: A hemispherical dart with a specific weight and diameter.
• Drop Height Apparatus: A mechanism to release the dart from a controlled height.
• Sample Clamping Device: A device to securely hold the film sample over a circular opening without slippage.
• Measurement Tools: Instruments to measure the weight of the dart and the height of the drop accurately.

Precautions

• Safety Measures: Proper safety measures should be in place to protect operators from the falling dart and any debris from film breakage.
• Sample Conditioning: Samples should be conditioned according to specified environmental conditions to ensure consistent results.
• Calibration: The testing apparatus should be regularly calibrated to maintain accuracy.
• Proper Handling: Care should be taken to handle and prepare samples without introducing defects or stress that could affect the results.

By following these guidelines, ASTM D1709 ensures reliable and reproducible testing of the impact resistance of plastic films.