This article is provided by Jinan Saicheng Electronic Technology Co., Ltd

1、 Testing principles and core values

The weighing method moisture permeability tester is based on the cup method (moisture permeable cup weighing method), which accurately measures the rate of water vapor penetration through materials by simulating a humidity gradient environment. The core principle is:

Humidity difference drive: At a constant temperature, a specific humidity difference is formed on both sides of the sample (such as 90% RH on the high humidity side and a dry environment on the low humidity side).

Quality change monitoring: Water vapor passes through the sample from the high humidity side and enters the low humidity side, where it is absorbed or directly evaporated by the desiccant. The water vapor transmission rate (WVTR, unit: g/(m ² · 24h)) is calculated by regularly weighing the mass change of the moisture permeable cup.

Data conversion: By combining the sample area, testing time, and mass change, key parameters such as moisture permeability coefficient are obtained to evaluate the barrier performance of the material.

Core values:

Quantitative barrier performance: directly reflects the barrier ability of PVDC sheet to water vapor, providing data support for packaging design.

Quality control: Check the consistency of moisture permeability of different batches of materials to ensure product stability.

Research and development optimization: Provide benchmark data for the development of new high barrier materials, guide formula and process improvement.

2、 Application scenarios and industry value

food packaging

Application: Test the moisture permeability of PVDC sheets used for high-temperature steaming bags and snack packaging to prevent food from getting damp and spoiling.

Medical packaging

Application: Evaluate the moisture permeability of medicinal aluminum foil, PVC hard sheet, and PVDC coated film to ensure that drugs are not affected by water vapor during storage.

building materials sector

Application: Test the moisture permeability of building waterproofing materials and evaluate their waterproof and breathable balance performance.

Textiles and non-woven fabrics

Application: Evaluate the moisture permeability of medical textiles such as surgical gowns and masks to ensure comfort and protection during wear.

3、 Execution standards and testing specifications

Main standards

GB/T 1037: Test method for water vapor transmission rate of plastic films and sheets (cup method).

GB/T 17030-2019: Test Method for Water Vapor Transmittance of PVDC Film for Food Packaging.

ASTM E96: Standard Test Method for Water Vapor Transmittance of Materials.

ISO 2528: Determination of water vapor transmission rate of plastic films and sheets (gravimetric method).

Test Process

Sample preparation: Cut a circular sample with a diameter of 74 mm to ensure a smooth and defect free surface.

Preprocessing: Place in a standard environment (23 ℃/50% RH) for 24 hours to eliminate stress effects.

Install the sample: Clamp the sample in a breathable cup and seal the edge to prevent side leakage.

Environmental control: Set the test temperature (such as 38 ℃) and humidity (such as 90% RH), and start the equipment.

Data recording: Automatically record quality changes, calculate WVTR, and generate reports.