Explain the principle and measurement method of hydrophilic non-woven fabric water absorption?

Update:08 Apr 2021

Principle of Hydrophilic Nonwoven Fabric Due to process […]

Principle of Hydrophilic Nonwoven Fabric
Due to processing characteristics and product cost, non-woven fabrics have used synthetic fibers for a long time, and polyester and polypropylene are the most. In a few cases, synthetic fibers and natural fibers are mixed, but the hydrophilicity of the product is poor.
Non-woven fabrics have higher hydrophilicity requirements for medical and sanitary materials and materials used for wiping and wiping. In the medical and healthcare fields, disinfection wipes, wound dressings, hemostatic strips, ribbons, gauze balls, ointment cloths and absorbent pads need to have good properties for absorbing blood and liquid drugs. Absorbent disposable materials, such as baby diapers, sanitary napkins, adult incontinence pads, have higher requirements for hydrophilic materials. There are disposable underwear, clothing lining cloth, shoe village cloth and other wearing materials that can also have certain requirements for hydrophilicity.
Principle of Hydrophilic Nonwoven Fabric
In the field of family health, all hydrophilic materials such as finger cloths for children, beautiful finger cloths and furniture, pipes, and cleaning cloths for cooking utensils can have corresponding requirements. In addition, many industrial fabrics such as battery separators are required to have high electrolyte absorption capacity, so hydrophilicity also puts forward certain requirements.
Hydrophilic finishing is to cover the fiber surface with a hydrophilic agent to form a hydrophilic film to improve its hydrophilicity. The hydrophilic film has a certain degree of conductivity and can improve the antistatic properties of the material. The method is simple and easy to use, and the principle is mature.

Water absorption test
Non-woven fabric products for medical and health use generally have water absorption or hygroscopicity requirements, so a water absorption test must be carried out. The water absorption is an important indicator of this type of product. The water absorption time or water absorption is often used to determine the water absorption of the product.
(1) Determination of water absorption time
The water absorption test method in the ASTM standard is as follows: a cylindrical metal mesh basket with open ends, 6.4am high, 3.8cm in diameter, and 3g in weight, is woven with 20 gauge stainless steel wire, and the mesh size is about 3cm×3cm. Take 5 samples along the running direction of the machine, the width of the samples is 76mm, and the length is based on its mass (5ょ0.g as the standard. The test is carried out at room temperature, and each sample is rolled into a roll with the same diameter along the length direction. Put it into a metal mesh basket with both ends slightly beyond the mesh basket. Then drop the mesh basket with the sample into a container containing water from a height of 25cm, and record the time required for the entire pattern to be completely wetted. Test 5 times , Find the average value, that is, the water absorption time.
Hydrophilic non-woven fabric test method
(2) Determination of water absorption
(2) Determination of water absorption
First, take 6 samples of 203mm×203mm along the 45° oblique direction of the non-woven fabric. If the fixed weight exceeds 80g/m2, 3 samples can be taken. The sample device uses galvanized metal wire to woven a metal mesh with a specification of 230mm×230m, and each mesh is about 12.5m×12.5mm. The quality is adjusted to the same value. At the same time, a number of deep dishes are prepared, each with a depth of about 80mm. The specification is about 254mmx254m, and there are several shallow plates, the size is based on the standard that can accommodate the metal mesh, and the calibration quality is the same.
During the test, first weigh the dry sample at room temperature to the nearest 0.1g, then place the sample on the metal mesh, fill the deep dish with water, the depth of water is about 65mm, and put the metal mesh with the sample into it In the dish, wait for the sample to be completely soaked, and then immerse it in the dish for 1 min. Lift the metal mesh and sample out of the water, place them horizontally on a wooden or metal rod and let them drip for 10 minutes, then immediately move them to the shallow dish Weigh in the middle, and subtract the mass of the shallow pan, metal mesh and dry sample from the obtained weight to get the water absorption of the sample. The water absorption rate is calculated as follows:
The water absorption rate of the sample = the water absorption of the domain sample / the dry weight of the sample x 100%

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