ISO 7765-1: The Core Testing Standard for Impact Resistance of Plastic Films

As an indispensable basic material in modern industry and daily life, plastic films are widely used in various fields such as food packaging, electronic insulation, agricultural mulching films, and medical protection. Their impact resistance directly determines the reliability of products during processing, transportation, and use—insufficient impact resistance of food packaging films may easily lead to rupture during handling and subsequent food contamination, while poor impact resistance of electronic insulation films may cause short-circuit risks. ISO 7765-1 “Plastics films and sheeting – Determination of impact resistance – Bahagian 1: Staircase method”, as a core internationally recognized testing standard, provides accurate and comparable quantitative evaluation criteria for the impact resistance of plastic films through scientific and standardized testing methods, serving as a key technical support for ensuring material quality and end-product safety.

saya. Standard Origin and Core Positioning: Understanding ISO 7765-1
ISO 7765-1 is a specialized testing standard first released by the International Organization for Standardization (ISO) in December 1988. Its full name is “Plastics films and sheeting — Determination of impact resistance by the free-falling dart method — Part 1: Staircase method”, which belongs to the mechanical performance testing standard system for plastic materials. This standard does not exist in isolation; instead, it is an important part of the ISO 7765 series standards, and together with Part 2 “Instrumented method”, forms a complete technical framework for free-falling dart impact testing of plastic films. Since its release, the authority of its technical content has been recognized worldwide, and many countries have equivalently adopted it as their national standards. Sebagai contoh, China’s GB/T 9639.1-2008 fully adopts ISO 7765-1:1988 with only minor editorial modifications, ensuring the mutual recognition of test results at home and abroad.
In terms of scope of application, ISO 7765-1 is explicitly applicable to plastic films and plastic sheets with a thickness of less than 1mm, covering mainstream materials such as polyethylene (PE), polipropilena (PP), polyester (PET), and polyvinyl chloride (PVC), as well as various structural forms including single-layer films and multi-layer composite films. Its core positioning is to determine the impact energy (expressed as impact failure mass) that causes 50% of the specimens to break under specified impact conditions through the classic “staircase method” testing approach, thereby objectively reflecting the material’s ability to resist sudden impacts and providing scientific basis for material research and development, production quality control, market access, and other links.

II. Technical Core: Testing Specifications and Principles of ISO 7765-1
The scientificity of ISO 7765-1 stems from the refined specifications for the entire testing process, with clear requirements for every link from instrument configuration, specimen preparation to testing procedures and data processing, ensuring the accuracy, kebolehulangan, and comparability of test results. Its core technical system can be summarized as “two core testing methods and five key testing links”:
1. Two Core Testing Methods: Adapting to Materials with Different Performances
Based on differences in dart parameters, the standard specifies two complementary testing methods, which are respectively adapted to plastic films with different impact resistance properties, and the test data of the two methods cannot be directly compared:
•Method A: Uses a hemispherical dart with a head diameter of (38±1) mm and a fixed drop height of (0.66±0.01) m. It is applicable to materials with an impact failure mass in the range of 0.05kg~2kg, and is mostly used for thin and light films with relatively weak impact resistance, such as food cling films and ordinary packaging films.
•Method B: Uses a hemispherical dart with a head diameter of (50±1) mm and a drop height increased to (1.50±0.01) m. It is applicable to materials with an impact failure mass in the range of 0.3kg~2kg, and is more suitable for testing thicker films with stronger impact resistance, such as heavy-duty films for industrial packaging and agricultural mulching films.
2. Five Key Testing Links: From Preparation to Data Interpretation
(1) Specimen Preparation: Ensuring Representativeness and Consistency
Specimens shall be randomly selected from different positions of the entire roll of film to ensure coverage of the edge and middle areas of the roll, avoiding the impact of material uniformity issues on test results. The size of the specimen shall be suitable for the annular fixture, usually the full-width film or a circular specimen with a diameter of not less than 150mm, and the specimen shall be free of wrinkles, scratches, and impurities. Pada masa yang sama, the standard clearly requires that the deviation between the actual thickness of the specimen and the nominal thickness or average thickness shall not exceed ±10%, because the thickness of the film has a significant impact on its impact resistance, and excessive thickness deviation will lead to distortion of test data.
(2) Instrument Configuration: Precisely Controlling Impact Conditions
The core testing equipment is a free-falling dart impact tester, which is mainly composed of an adjustable bracket, an electromagnet (used to control dart release), an annular fixture, a dart, and counterweights. Antaranya, the inner diameter of the annular fixture shall be strictly controlled at (125±2) mm, the upper and lower fixtures shall be kept parallel, and the surface in contact with the specimen shall be attached with a rubber gasket with a Shore hardness A of 50~60 to ensure no slip when clamping the specimen and reduce the impact of thickness error on the clamping effect. The mass of the dart can be adjusted by adding or removing counterweights, and the mass of the counterweights shall be uniform to realize “staircase” pelarasan.
(3) Conditioning and Test Environment: Eliminating External Interference
Before testing, the specimens shall be conditioned in a standard environment (temperature 23℃±2℃, relative humidity 50%±5%) for at least 4 hours to eliminate internal stress generated by temperature and humidity changes during material storage and transportation, ensuring that the test is carried out under stable conditions. During the test, the ambient temperature and humidity shall be kept stable continuously to avoid external factors such as air flow and vibration interfering with the free fall of the dart.
(4) Test Execution: Following the “Staircase Adjustment” Logic
The core logic of the test is the “staircase method”: itu dia, according to the damage situation of the previous specimen, the total mass of the dart (the sum of the mass of the dart, counterweights, and locking ring) is adjusted by adding or removing counterweights. If the previous specimen is damaged, the mass of the dart is reduced; if not damaged, the mass of the dart is increased. The amplitude of each mass adjustment (staircase) shall be reasonably set according to material performance, usually 50g or 100g. Through multiple repeated tests (generally no less than 20 valid tests), sufficient data on damaged and undamaged specimens are accumulated to provide a basis for subsequent statistical analysis.
(5) Data Processing and Result Interpretation: Focusing on “50% Failure Mass”
The standard specifies that the test result is expressed as “impact failure mass (m)”, which refers to the total mass of the dart that causes 50% of the specimens to break under specified test conditions. This data shall be calculated by statistical methods, reflecting the core indicator of the material’s impact resistance—the larger the impact failure mass, the stronger the material’s ability to resist impact. Sebagai contoh, if a PE film has an impact failure mass of 0.8kg tested by Method A, it indicates that under the test conditions, a dart with a mass of 0.8kg has a 50% probability of causing the film to break. Pada masa yang sama, the damage morphology of the specimen (such as tearing, perforation, dan lain-lain.) shall also be recorded to provide supplementary information for material performance analysis.

III. Application Value: Full-Chain Protection from Material R&D to End-Product Safety
The application of ISO 7765-1 runs through the entire chain of the plastic film industry, playing an irreplaceable role in material research and development, production quality control, market access, and other links:
In the field of material research and development, this standard provides a quantitative basis for the formula optimization of new film materials. Researchers can quickly screen out schemes with better impact resistance by testing the impact failure mass of films with different formulas (such as adding tougheners, adjusting resin models). Sebagai contoh, in the research and development of nano-reinforced plastic films, the effect of nano-particle addition on the improvement of film impact resistance can be accurately verified through ISO 7765-1 ujian.
In the production quality control link, this standard is a core means to ensure product consistency. By conducting sampling tests on each batch of products, manufacturers can timely detect abnormalities in impact resistance caused by raw material fluctuations and changes in processing technology, avoiding unqualified products from entering the market. Data from a food packaging film manufacturer shows that by strictly implementing the ISO 7765-1 testing standard, the unqualified rate of its products has dropped from 3.5% kepada 0.8%, effectively reducing the risk of customer complaints.
In the end-application and market access links, this standard provides a scientific basis for material selection in different industries. Sebagai contoh, the food industry requires packaging films to have sufficient impact resistance to cope with collisions during transportation, and the electronic industry has clear threshold requirements for the impact resistance of insulation films. These requirements can be verified through ISO 7765-1 keputusan ujian. In international trade, a test report complying with this standard is a “pass” for products to enter the international market, ensuring that products meet the quality specifications of the target market.

IV. Precautions and Development Trends: Practical Key Points and Future Directions of the Standard
In the practical application of ISO 7765-1, several key points need to be paid attention to: first, the test data of the two testing methods (Method A and Method B) cannot be directly compared, and the appropriate method shall be selected according to material characteristics and application scenarios; second, the thickness uniformity and surface state of the specimen have a significant impact on the test results, so the quality of the specimen must be strictly controlled; third, factors such as ambient temperature, kelembapan, and air flow during the test will interfere with the falling state of the dart, so the test environment must meet the standard requirements. For multi-layer composite films, it is also necessary to combine fracture analysis and other means to conduct in-depth research on the impact of interlayer bonding state on the overall impact resistance.
With the development of the plastic industry, ISO 7765-1 is constantly evolving in coordination with industry needs. In the future, the development direction of this standard will mainly focus on three aspects: first, adapting to the testing needs of new materials, optimizing testing parameters and evaluation methods for emerging materials such as polymer composite materials, nano-reinforced films, and degradable plastic films; second, promoting the intelligent upgrading of testing technology, combining the Internet of Things and big data technology to realize real-time collection, remote monitoring, and automatic analysis of test data, improving test efficiency and accuracy; third, strengthening the connection with downstream industry standards, further clarifying the impact resistance thresholds under different application scenarios, and making the standard more practically guiding.
For enterprises and testing institutions, accurately mastering the testing specifications of the ISO 7765-1 standard is not only the basis for improving product quality and ensuring market competitiveness, but also the responsibility to promote the high-quality development of the industry. Under the background of continuous innovation in material technology, only by deeply understanding the core logic of the standard and optimizing the testing process in combination with practical experience can the technical support role of the standard be fully exerted.

In conclusion, as the core international standard for testing the impact resistance of plastic films, ISO 7765-1 provides a unified and accurate technical framework for material performance evaluation with its scientific staircase method testing approach, running through the entire chain of material research and development, production, and application. Under the development trend of green manufacturing and intelligent manufacturing, this standard will continue to iterate and upgrade, providing more powerful technical guarantee for the high-quality development of the plastic film industry.

Our Product GA-5052 Falling Dart Impact Tester meets this standard.

Penguji Kesan Dart Jatuh
Piawaian
GB/T 9639.1-2008、ISO 7765-1-1988、 ASTM D1709、JIS K7124-1

pengenalan
It is designed for determination of the impact resistance of packaging materials such as plastic films, laminates and paper by a free falling dart from a certain height. This instrument is designed according to ASTM D1709 with method A & B.

Technical Features
1.Two test methods, Method A and Method B.
2.Electromagnetic suspension and automatic release of the falling dart reduce the errors caused by manual operation.
3.Pneumatic clamping, 2 starting modes ofmanual and pedal switch and built-in observation light are convenient for user’s operation.
4.Professional software supports multi-unit result display, graphic display of testing process and data export and printing.
5.Equipped with USB port and micro printer port which is convenient to the data transmission and PC connection.

Prinsip
Before starting the test, choose test method, and estimate an initial mass and Δm. Start the test. If the first specimen fails, decrease the mass of the falling dart by Δm. If the first specimen is not a failure, increase the mass of the falling dart by Δm. Continue the test according to this rule. In brief, increase or decrease by Δm according to whether the former specimen is a failure or not. After 20 specimens, calculate the total number of failed specimens N. If N equals to 10, the test is over. If N is less than 10, add specimens and continue to test until N equals to 10. If N is greater than 10, add specimen and continue the test until the number of non-failure specimens reaches 10. Then the tester calculates the test results automatically according to specific formulas.