ASTM D 3420 Plastic Film Impact Resistance

The assessment of a film's resistance to impact-puncture penetration is covered by the ASTM D 3420 standard test procedure. The results of this test do not reveal the specimen's behaviour after yielding or how the impact energy is absorbed by the specimen when it is deforming under the impact loading.

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ASTM D 3420 Plastic Film Impact Resistance

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Precision-driven testing for dimensional accuracy and compliance

Overview
Scope, Applications, and Benefits
Test Process
Specifications
Instrumentation
Results and Deliverables

Overview

ASTM D3420 describes a test method using one of two free-falling dart techniques to determine the impact resistance of plastic films and thin sheeting materials. Impact resistance is an essential property for flexible plastic films in packaging, consumer products, and industrial applications because materials are often subjected to mechanical shock during handling, transportation, stacking, or accidental drops.

The test measures the energy to cause failure in a film specimen and provides a quantitative indication of film toughness and durability. ASTM D3420 supports material comparison, quality control, and performance evaluation under realistic service conditions.

Scope, Applications, and Benefits

Scope

ASTM D3420 outlines procedures for evaluating the relative impact resistance of plastic films under controlled laboratory conditions. It evaluates:

Resistance of films to sudden impact or mechanical shock
Energy required to initiate film failure
Failure behavior such as tearing, puncturing, or propagating
Consistency of film performance across multiple samples

The method applies to plastic films and thin sheets, typically with thicknesses up to 1.0 mm.

Applications

Flexible and rigid packaging materials
Single-layer polymer films
Co-extruded and laminated films
Barrier and protective films
Quality control of film production
Material comparison during product development
Failure analysis of packaging materials

Benefits

Provides quantitative impact resistance values
Helps optimize packaging design and durability
Supports material selection for demanding handling conditions
Detects processing, formulation, or thickness variations
Enhances quality assurance and product reliability
Allows standardized comparison between different film materials

Test Process

Sample Conditioning

Film specimens are conditioned at controlled temperature and humidity to minimize environmental effects on impact performance.

Specimen Mounting

The plastic film is securely clamped over a test opening to ensure proper alignment and uniform stress distribution.

Dart Impact Application

A hemispherically tipped weighted dart is dropped from a specified height, delivering a known impact energy to the center of the film.

Failure Observation & Energy Determination

The specimen is examined for tearing or puncture. Dart weight or drop height is adjusted to determine the minimum energy required to cause failure.

Technical Specifications

Parameter	Details
Applicable Materials	Plastic films and thin plastic sheets
Typical Thickness Range	Films ≤ 1.0 mm
Specimen Size	Typically ~76 mm (3 in.) diameter or as specified
Impact Tip	Hemispherical dart
Measured Outputs	Impact failure energy, failure mode
Units Reported	Joules or gram-force centimeter

Instrumentation Used for Testing

Dart impact testing apparatus
Hemispherically tipped weighted dart
Film clamping fixture
Controlled environmental conditioning chamber
Measuring scale for dart mass and drop height
Data recording and analysis system

Results and Deliverables

Impact failure energy values
Identification of failure mode (tear, puncture, propagation)
Assessment of film toughness and durability
Comparative data for material selection and optimization
Documentation supporting quality control and product qualification

Frequently Asked Questions

It measures their resistance to impact puncture, especially their toughness at various strain rates, which could be dynamic in real life.

Procedure A uses a pendulum with energy recorded in joules or cm·kgf and is suitable for ambient temperature tests. Procedure B includes marking specimens to detect slippage, uses adjustable pendulum weights, and records energy based on apparatus capacity and scale readings.

The test does not adjust results for the thickness of materials, cannot assess the performance of materials in compression beyond yield strength, and does not have any test methods for non-ambient conditions.