Rolls of white fabric stacked on end
If a water-repellent finish on polyester fabric chases the spray rating alone, the film on the fibre surface tends to run thick, the hand of the fabric turns stiff and rough with it, and continuous water repellency and wearing comfort become hard to reconcile.
Chemi Tech supplies water repellents for polyester and nylon fabrics and for outdoor shell jacket systems, drawn from the water repellent KMF-603 series; the ratio of the finishing bath is set by the fibre type, the fabric weight and the finishing process. KMF-603 is designed around continuous water repellency with the hand kept in view, the film on the fibre surface is continuous and does not fail easily after washing, and it is compatible with resin softeners in the same bath; the same series also offers KMWF-102, a fluorine-free product that fits export orders which have to hold perfluorinated indicators down. Chemi Tech verifies water repellency against the fibre type and the finishing process, and gives the customer the water repellent that fits.
Advantages of Chemi Tech Water Repellents
Chemi Tech water repellent KMF-603 series is designed around continuous water repellency, the film on the fibre surface is continuous, and water repellency declines slowly after the fabric is washed; and the hand is soft, free of stiffness and roughness, so wearing comfort is not affected; moreover, it is compatible with resin softeners in the same bath, and the finishing sequence does not have to be split; continuous water repellency and hand are reconciled together, and the finishing needs of polyester and nylon fabrics are met at once.
Industry Pain Points and Solutions
The difficulty in water-repellent finishing of polyester fabric is that water-repellent film formation and hand are hard to satisfy at the same time; the consequence is that the spray rating passes while the hand turns stiff, or the hand is acceptable while water repellency falls short.
The core difficulty lies in the balance between the continuity of the film and the hand. When the film is too thick, water repellency is stable but the hand turns stiff; when the film is too thin, the hand is acceptable but water repellency fades quickly. Chemi Tech recommends KMF-603, which reconciles continuous water repellency with hand, compounded into the finishing bath so that the film stays continuous without turning stiff.
The next difficulty lies in the loss of water repellency after washing. With some finishing agents the film is not continuous, and water repellency falls off after a few washes. With Chemi Tech KMF-603 the film on the fibre surface is continuous and does not fail easily after washing.
The last issue lies in the indicators on fluorine-free export orders. For export orders that have to hold perfluorinated indicators down, ordinary fluorinated products are hard to match. Chemi Tech answers with the fluorine-free product KMWF-102, and the comparison is run against the fluorine-free test criteria, so the perfluorinated concern on export orders is reduced accordingly.
Typical Operating Conditions and Verification
Customer: an outdoor fabric finishing company in Hubei, for a water-repellent finishing line for polyester shell jacket fabric.
After water-repellent finishing the plant's polyester fabric came out stiff in the hand, customers reported that wearing comfort had dropped, and the finishing agent previously used lost water repellency markedly after washing. The solution Chemi Tech water repellent gave for the situation was: taking the fibre type and the fabric weight into account, choose KMF-603, re-calibrate the finishing bath concentration and the curing conditions, and check the compatibility of the softener in the same bath as well. After the finishing line was adjusted, the hand of the fabric came back soft, water repellency stayed stable after washing, and the spray rating returned within the customer's threshold.
Frequently Asked Questions
After a fabric is given a water-repellent finish, will washing make the water-repellent layer fail quickly?
It can indeed, since with some finishing agents the film is on the brittle side and water repellency falls off after a few washes. Chemi Tech has verified the water repellency of KMF-603 against washing and finishing conditions, and only recommends it for the line once the film continuity data is steady. The finishing bath concentration depends on the fibre type and the fabric weight, and Chemi Tech gives its recommendation after the washing comparison.