GB/T 15171-2025 Sealing Performance Test for Flexible Packaging Components will be officially released on August 1, 2025, and will be implemented from February 1, 2026. At that time, it will fully replace the old version of the standard GB/T 15171-1994 "Sealing Performance Test Method for Flexible Packaging Components" that has been in use for more than 30 years. This revision is a major technological innovation in the field of packaging sealing testing, aimed at adapting to the diverse and high-quality development needs of the modern packaging industry.

New and old standards updated in:

• Old version (1994): Only applicable to 'soft pack packages'.

• New version (2025): Applicable to "flexible packaging, semi-rigid packaging, and rigid packaging", and clearly covers "non vacuum packaging" and "sealed packaging without contents".

Testing method:

On the basis of retaining and optimizing the traditional "underwater bubble method", the new version of the standard has added the "vacuum attenuation method", which solves the pain points of the old version of the standard, such as strong subjectivity and difficulty in quantifying small leaks.

• Underwater bubble method: qualitative or semi quantitative, determining leaks by observing bubbles with the naked eye, intuitive but relying on manual labor, insensitive to small leaks.

• Vacuum attenuation method: quantitative, non-destructive, objective. By monitoring the changes in vacuum degree inside the testing chamber with high-precision pressure sensors, the "vacuum decay rate" (Q) is calculated to accurately quantify the degree of leakage, which is particularly suitable for industries such as pharmaceuticals and precision electronics that require sealing.

requirement:

• Key terms such as' soft packaging ',' hard packaging ',' vacuum decay rate ',' target vacuum degree ',' reference vacuum degree 'have been added.

• Revised the definition of 'sealing performance' to better align with modern testing techniques.

• The outdated term 'soft pack assembly' has been removed.

Optimization plan:

• Removed 'Method 2' (dye penetration method) from the old version, focusing on two more mainstream and advanced methods.

• The instrument and steps of the 'underwater bubble method' have been optimized, such as replacing the 'sample fixture' with a 'transparent porous pressure plate' for easier operation; the test water has been relaxed from 'distilled water' to 'clean and transparent test water' for greater operability.

Recommended testing instruments:

Method 1: Underwater Bubble Method

• Principle: Immerse the sample in a vacuum chamber containing test water, and evacuate to create a pressure difference between the inside and outside of the sample. If there is a leak in the sample, the internal gas will escape and form continuous bubbles; Or external water may seep into the interior of the sample.

• Applicability: Suitable for packaging components whose outer material is not significantly affected by the test water. It is a classic and intuitive detection method.

• Main instrument requirements

• Vacuum source: capable of achieving a maximum vacuum degree of not less than 95 kPa within 30s~60s.

• Vacuum gauge: accuracy not lower than level 1.

• Vacuum chamber: composed of a sealed lid and a transparent container, capable of withstanding a pressure of 100 kPa.

• Transparent porous pressure plate: used to immerse the sample in water without affecting observation.

• Control device: including vacuum tube valve, vacuum degree adjustment device, and intake pipe valve.

  Recommended testing instrument: LT-02P sealing tester

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• Method 2: Vacuum decay method

• Principle: Place the sample in a sealed testing chamber, evacuate to the target vacuum level, and create a pressure difference between the inside and outside of the sample. Use high-precision pressure sensors to monitor the decay of vacuum degree (i.e. pressure rise) in the test chamber during the experiment. Leakage can cause an increase in pressure inside the chamber, and the size of the leakage can be quantified by calculating the 'vacuum decay rate'.

• Applicability: Suitable for non-destructive and quantitative testing of soft and hard packaging, especially widely used in the pharmaceutical industry.

• Main instrument requirements

• Test chamber: includes a lower chamber for placing the sample and an upper chamber for closing the test chamber (during flexible packaging testing, the upper chamber is usually made of flexible material).

• Gas conducting layer (flexible packaging): Ensure that the gas on the outside of the sample can flow normally to the sensor.

• Vacuum source: capable of achieving the target vacuum degree.

• Pressure sensor: accuracy not lower than level 1.

• Gas flow controller: used to verify the sensitivity of the testing system.

• Leak free standard sample: used to eliminate background errors in the system.

• Recommended testing instrument: LT-02M vacuum attenuation instrument

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GB/T 15171-2025 is a progressive and technological standard, and its implementation will provide strong technical support for the high-quality development of China's packaging industry and product quality and safety. For more detailed information, please follow us at Shandong Puchuang Industrial Technology Co., Ltd!