Mechanical Performance Testing: The Foundation of Strength and Durability

1. Mechanical Performance Testing: The Foundation of Strength and Durability

The mechanical properties of nonwoven fabric determine its resistance to tension and tearing in practical applications. Common testing items include:

Tensile Strength and Elongation at Break (ASTM D5034): A tensile testing machine simulates stress conditions to evaluate load-bearing capacity in both longitudinal and transverse directions. For example, medical surgical gowns must meet a longitudinal tensile strength of ≥30N.

Tear Strength (ASTM D5734): The Elmendorf tear method measures resistance to crack propagation, particularly critical for geotextiles and outdoor applications.

Bursting Strength (GB/T 19976): Hydraulic or steel ball burst tests simulate localized stress, such as the friction resistance required for baby diaper backsheets.

Industry Challenge: Some manufacturers reduce fiber weight (GSM) to cut costs, leading to substandard mechanical performance. Comprehensive control requires integrating GSM measurements with mechanical testing.

2. Breathability and Filtration Efficiency: Core Validation of Functionality

Breathability and filtration efficiency are key indicators for grading nonwoven fabrics, especially in medical protection and air filtration:

Air Permeability Test (GB/T 5453): Measures air flow under fixed pressure differences. For instance, surgical drapes require an air permeability of ≥800L/(m²·s) for comfort.

Particle Filtration Efficiency (PFE) and Bacterial Filtration Efficiency (BFE) (GB 19083-2010): Aerosol generators and particle counters verify the interception rate of melt-blown fabric for 0.3μm particles (e.g., N95 masks) or 3μm bacteria (requiring ≥95%).

Liquid Barrier Performance (ISO 22610): Tests synthetic blood penetration resistance for medical protective clothing to prevent cross-contamination.

Case Study: In 2020, a mask manufacturer experienced a drop in PFE from 99% to 70% due to charge decay in melt-blown fabric, highlighting the importance of electret process testing.

3. Chemical Safety Testing: Managing Hidden Risks

Nonwoven fabrics may retain harmful chemicals during processing, requiring strict testing to ensure end-product safety:

Formaldehyde and Optical Brighteners (GB/T 2912.1): High-performance liquid chromatography (HPLC) quantifies residues, with infant products requiring formaldehyde levels ≤20mg/kg.

Heavy Metal Migration (EN 71-3): Simulates saliva or sweat environments to detect lead, cadmium, and other leaching substances, preventing contamination in toy packaging.

pH Value Test (ISO 3071): Nonwovens in direct skin contact (e.g., wipes) must maintain a pH of 4.0–8.5 to avoid irritation.

Technological Trend: The EU’s REACH regulation now restricts PFAS, driving the adoption of high-precision testing equipment like GC-MS (gas chromatography-mass spectrometry).

Tags: Physical property testing, industry standards, chemical safety