How to achieve fluorine-free water repellency and easy decontamination of textiles

1 Choose a special fluorine-free water repellent

To achieve fluorine-free water repellency and easy decontamination, we must first find out the reasons why textile oil stains should not be washed off. The main component of oil is non-polar oil, while water is polar. According to the principle of intermolecular with similar polarities attracting each other and opposite sexes repelling each other in physical chemistry, non-polar oil stains repel polar water, and it is not easy to pull it from the fiber into the water by the general washing method.

2 Do a good job of pre-treatment to remove impurities on the cloth surface

The water-repellent finishing of fluorine-free water-repellent agent has certain requirements for fabric pretreatment and residual auxiliaries. If the oil agent is not cleanly removed, the fabric will have poor water absorption, and the fabric will carry liquid in the process of rapid padding. At the same time, the water repellent cannot be directly coated on the surface of each fiber, and a continuous hydrophobic protective film cannot be formed on each fiber, and it is difficult to achieve a good water repellent effect. The remaining pre-treatment auxiliaries and dyeing auxiliaries on the fabric before finishing, such as levelling agents and ordinary penetrants, are all hydrophilic substances, which cannot volatilize on the fabric after drying, and the remaining substances will increase the surface tension of the fabric. It will also affect the water repellent effect. Silicon-containing defoamers affect the film formation of the water repellent on the surface of the fiber, and also affect the effect of the water repellent. Therefore, it is necessary to remove the oily agent on the fabric before finishing, and clean up the pre-treatment auxiliaries, leveling agents, etc., and do not use silicon-containing defoamers.

3 Choose the right crosslinking agent

In order to improve the washability of the fluorine-free water repellent, an appropriate amount of crosslinking agent can be added to the formula. The cross-linking agent that has little effect on the easy decontamination performance is screened through experiments. Generally, the cross-linking agents on the market are polar, and most of them have no effect on easy decontamination. It is recommended to screen the appropriate cross-linking agent and its dosage through tests before production.

4 Choose the right penetrant

When the fabric density is high and the liquid-carrying rate is low, an appropriate amount of penetrant can be added to the working fluid. However, when the working fluid contains substances that have the opposite mechanism to the water repellent and easy decontamination function, the water repellent and easy decontamination functions will be significantly reduced. Ordinary penetrants cannot volatilize during the fiber drying process, and remain on the cloth surface, increasing the surface tension of the cloth surface, thus reducing the water repellent effect. Non-remoisturizing penetrants such as isopropanol can improve the permeability of the cloth surface in the working fluid. At the same time, under dry conditions, it will evaporate with water and will not remain on the cloth surface. When the amount is appropriate, it will not reduce the effect of the water repellent . Therefore, when making fluorine-free water repellent and easy stain removal finishing of fabrics with higher density and low liquid-carrying rate, an appropriate amount of non-rewetting penetrant can be added to the working fluid.