Close-up of water beading on the fabric surface
Polyester shell fabric on outdoor jackets is rained on again and again through the wet season; water climbs the capillary channel along the stitching, sheets of damp marks bleed out at the shoulder and back seams, and wet-through complaints in the returns log multiply with it.
Chemi Tech offers the KMF-603 water repellent for the water-repellent finishing of polyester and nylon fabrics, with the dosage adjusted flexibly according to the substrate's gram weight and the curing temperature. This grade is a fluorine-based water repellent: it forms a continuous film on the fibre surface, and the hand feel stays soft rather than stiff; its compatibility in the same bath with resin softeners is good. Setting the measured seam wicking height alongside the spray rating gives the suitable KMF-603 dosage.
Advantages of Chemi Tech Water Repellents
Chemi Tech KMF-603 series water repellent is formulated for polyester and nylon fabrics. Its water-repellent film is continuous, forming a complete repellent layer on the fibre surface with a stable spray rating; the hand feel stays soft without stiffening, and the fabric's drape is unaffected after finishing; its wash resistance is outstanding, with the spray score still holding above the order-acceptance threshold after repeated washes; its compatibility in the same bath with resin softeners is good, so the finishing stage needs no extra separation; and the dosage is adjusted flexibly to the substrate's gram weight, covering both light and heavy fabrics.
Industry Pain Points and Solutions
Water-repellent finishing problems on polyester fabric stem mostly from the combined action of film continuity and a mismatched curing window, and they end up showing in two places: a low starting spray rating and seam wicking.
The fabric body's spray rating meets spec, yet the stitching and needle holes are the first to wet through, and the garment inspection deduction centres on the seam. KMF-603's concentration is set by the substrate material, and it can markedly shorten the wicking height at the seam.
An insufficient curing temperature lets the repellent film's continuity drop, and the fall in rating after washing comes earlier with it. Factoring in the shifts in the substrate's gram weight and the curing temperature, the curing curve can be adjusted to the gram weight, keeping the film layer intact.
A stiff hand feel is the most common source of customer complaints in water-repellent finishing, and the fabric's added value suffers with it. KMF-603 forms a soft film, and the hand feel keeps its original character after finishing, with end-customer feedback stable and controllable.
Typical Operating Conditions and Verification
Customer case: an outdoor apparel fabric finisher in Zhejiang, for the water-repellent finishing line of polyester four-way stretch.
The customer's inspection added a seam rain test; the existing finishing formula never improved the wicking marks at the stitching, and the rectification pressure fell on the finishing workshop. Following comparison testing of the seam wicking height and the spray rating, the finisher selected KMF-603 as the water-repellent finishing agent, with the dosage set by the polyester gram weight. Once in use, the fabric body's spray rating met spec stably; the wet marks in the seam rain test were held outside the stitching; the rating stayed within the order-acceptance band after repeated washes, and orders were released on schedule.
Frequently Asked Questions
After fluorine-based finishing, will the fabric's hand feel become noticeably stiffer?
Whether the hand feels stiff or soft depends entirely on whether the repellent film forms continuously on the fibre surface and whether crosslinking is complete. KMF-603 has completed hand-feel and wash-resistance comparison testing on polyester and nylon fabrics, and its softness stays stable within the recommended range. The actual dosage takes the substrate's gram weight and the curing temperature as its baseline; Chemi Tech sets the finishing concentration through a parallel comparison of the seam wicking height and the spray rating.