In the packaging and materials industry, the impact resistance of plastic films is a crucial material property. Understanding how a material behaves under impact helps ensure its reliability and safety in practical applications. This paper introduces two commonly used test methods for impact resistance of plastic film: free falling dart method and pendulum impact resistance method. These methods can be used to assess the impact resistance of materials under different conditions.

Free fall dart method
The free fall dart method is a method to test the impact resistance of materials. It determines the damage energy of plastic film or sheet sample by the impact of the free fall dart. This method is usually suitable for thin slice samples with a thickness of less than 1mm.

Plastic film impact resistance test you know how much

【 Test principle 】

The principle of the test is that when the free-falling dart falls freely from a certain height, it has a certain kinetic energy, and when it impacts the sample, part of the kinetic energy will be transferred to the sample. The impact resistance of the specimen depends on the amount of kinetic energy it can withstand. If the sample is damaged, the kinetic energy will be partially absorbed, so that the greater the mass of the sample affected by the impact, the greater the kinetic energy, the higher the impact resistance.

【 Test equipment 】

The test equipment required by the free fall dart method includes impact testing machine, sample fixture, electromagnet, positioning device, buffer and protection device, locking ring and so on. The drop dart used in the test is usually made of aluminum, phenolic plastic, or other low-density material of similar hardness, with a hemispherical head and a round handle for mounting and unloading weights.

【 Test method 】

The specific test steps include clamping the sample between the ring fixture, adding the appropriate weights, lifting the free fall dart to the specified height, and then releasing the free fall dart so that it freely falls to impact the sample. If the sample is not damaged, it can be retested. After the test, the impact strength was calculated according to the damage rate of the sample.

Anti-pendulum impact method
The anti-pendulum impact method is another commonly used method to test the impact resistance of plastic film, which evaluates its impact resistance by using a swinging hammer head to impact the specimen. This method is suitable for materials with impact damage mass greater than 50g.

Plastic film impact resistance test you know how much

【 Test principle 】

In the anti-pendulum impact method, the specimen is held in a specific position and the swinging hammer head is released, hitting the specimen. The impact resistance of the specimen depends on the impact force it can withstand.

【 Test equipment 】

The test equipment required for anti-pendulum impact method includes pendulum impact tester, sample fixture, pendulum system and hammer head. The design of the testing machine allows the hammer to swing at a certain speed and impact the sample.

【 Test method 】

The test method involves clamping the specimen in a fixture and then releasing the swinging hammer head so that it swings and shocks the specimen. If the sample is not damaged, it can be retested. After the test, the impact strength was calculated according to the damage rate of the sample.

Closing remarks
The impact resistance test of plastic film is a key step to ensure the quality and reliability of packaging materials and products in practical applications. Free fall dart method and anti-pendulum impact method are two commonly used test methods, they can help manufacturers and engineers to evaluate the impact resistance of materials under different conditions, so as to select the appropriate materials and improve product design to ensure that products will not be damaged during transportation, storage and use, improve product quality and protect the interests of consumers.