Factors of affecting fabric resistance to hydrostatic pressure test

Hydrostatic pressure test (also called water permeability test) is one of the important indexes of waterproof and moisture permeable fabrics. Hydrostatic pressure refers to the resistance encountered when water passes through fabrics. Under the condition of standard atmospheric pressure, the fabric bears the continuously rising water pressure until water drops seep out from the back of the fabric. At this time, the measured water pressure value is the hydrostatic pressure. The greater the hydrostatic pressure that the fabric can bear, the better the water resistance or leakage resistance. Today, Shanghai Qinsun will introduce the influencing factors in the hydrostatic test of fabric. So as to provide reference for textile testing enthusiasts.

First of all, let's understand the principle of fabric hydrostatic test:
Through dynamic test, static test and program test, the test specimen is fixed on the test area specified by the standard. The air pressure control puts the air pressure of 0-5bar into a built-in water tank filled with distilled water. The water tank is connected with a test head. After the test starts, the test pressure will be automatically controlled.

Secondly, the influencing factors in the water pressure test of fabrics:
(1) the tightness of fabric yarns. The gap between yarns will directly affect the water pressure resistance. Generally, the tighter the fabric structure, the better its water penetration resistance.
(2) The pore size of coating film. The larger the pore size of the film, the worse the hydrostatic pressure resistance of the coated fabric.
(3) The size of contact angle 0. When 0>90. The water resistance of the fabric increases with the increase of 0.
(4) Coating thickness. The coating is too thin, the coating agent is not easy to form a film continuously on the surface, and the water pressure resistance of the coated fabric is reduced; Thick coating improves the water pressure resistance of fabric.
(5) the thickness of the fabric. The thicker the fabric, the greater the wet resistance and the greater the water pressure resistance.
(6) Yarn thickness. For compact fabrics made of fibers with good hygroscopicity, the water penetration resistance of fabrics can be improved by reducing the yarn radius due to capillary effect.
(7) The performance of warp and weft yarns. Under the action of water pressure, the warp and weft yarns with good elasticity are easy to stretch, which leads to the formation of gaps between adjacent warp and weft yarns, and water droplets are easy to penetrate through them, which makes the water pressure resistance of fabrics lower.
(8) Coating quality. The whole cloth surface is required to be uniform and have a certain fastness. The better the coating quality, the better the water penetration resistance.
(9) Elasticity of fabric. Elastic fabrics also have a certain influence on water penetration resistance
(10) The sampling position and the flatness of the sample also have an impact on the data in the test process.

Technical indexes of water pressure resistance tester for fabrics
Test pressure: 0 ~ 5000 mbar
Pressure accuracy: 0.5%± 1 mbar
Resolution: 0.1 mbar
Rising rate: 1 ~ 1000 bar/min
Test area: 100cm2 (10cm2, 19.63cm2, 26cm2, 28cm2)
Sample thickness: 0 ~ 20 mm
Compressed air requirement: 6-8 bar (clean and dry air)
Overall dimensions: 450×500×600mm(W×D×H)
Weight: 60Kg
Power supply: AC100-240V,50/60Hz,50W

testing nominative
GB/T 4744, AATCC 127, EN 20811, BS 2823, BS 3424-26 29A/29C, BS 3321, BS 3321,ISO 811,ISO 1420A,DIN 53886,INDA IST 80.4,JIS L 1,092 A,JIS L 1, 092 B-b NF G07-057,ERT-120-1, 160-0,EDANA 120.2-02,ISO 16603,ASTM F1670, YYT 0700,ASTM F903.