Rows of footwear fabric stacked in place
If the water-repellent finish on footwear fabric is not a continuous film, repellency decays after a few washes and the upper turns water-permeable with it; if the repellency index is pursued single-mindedly, the film on the fibre surface is on the thick side, the upper feels stiff and harsh, and comfort in wear and repellency are hard to satisfy at once.
Chemi Tech supplies water repellents for the water-repellent finishing of footwear, nonwoven and industrial textiles, drawn from the water repellent KMF-801 series; the finish liquor ratio is set by fibre type, basis weight and finishing process. KMF-801 is designed around continuous repellency balanced with hand feel, the film on the fibre surface is continuous, it does not readily fail after washing, and it is compatible in the same bath with common adhesives and softeners. Chemi Tech verifies repellency performance against fibre type and finishing process, and matches the customer to a fitted water repellent.
Advantages of Chemi Tech Water Repellents
Chemi Tech water repellent KMF-801 series is designed around continuous repellency, the film on the fibre surface is continuous, and the repellency of footwear decays slowly after washing; moreover, the hand feel is soft, neither stiff nor harsh, so comfort in wear is unaffected; and it is compatible in the same bath with common adhesives and softeners, so the finishing step needs no splitting; it also contains no perfluorinated compounds, so concerns over export and test criteria are correspondingly reduced.
Industry Pain Points and Solutions
The difficulty in the water-repellent finishing of footwear lies in the hard choice between a repellent film and hand feel; the consequence is either a passing spray rating with a stiff hand, or an acceptable hand with insufficient repellency.
The decay of repellency on footwear fabric is a major pain point. With some finishing agents the film is not continuous, repellency falls after a few washes, and the upper turns water-permeable with it. Chemi Tech recommends dosing the continuously repellent KMF-801 into the finish liquor, so that the film is continuous and does not readily fail.
Next comes the hardening of hand feel. When the film is on the thick side repellency is stable but the upper stiffens and comfort in wear drops. KMF-801 from Chemi Tech is designed around a balance of repellency and hand feel, the film on the fibre surface is continuous and not stiff.
The last problem lies in same-bath compatibility. Footwear finishing is often carried out in the same bath as adhesives and softeners; if the auxiliaries are not compatible, both the finish effect and the hand feel suffer. Chemi Tech runs a same-bath comparison of KMF-801 against common auxiliaries, and the finishing step needs no splitting.
Typical Operating Conditions and Verification
Customer: a footwear finishing enterprise in Fujian, for the water-repellent finishing line of sports-shoe upper fabric.
At the plant the shoe upper fabric felt stiff after water-repellent finishing, customer feedback was that comfort in wear had dropped, and the finishing agent used before showed marked decay of repellency after washing. The solution Chemi Tech water repellent gave for the situation was: taking fibre type and basis weight into account, choose KMF-801, recalibrate the finish liquor concentration and the curing conditions, and check the same-bath adhesives and softeners for compatibility alongside. Once the finishing line was adjusted, the upper returned to a soft hand, repellency stayed stable after washing, and the spray rating came back within the customer's threshold.
Frequently Asked Questions
Once footwear has been water-repellent finished, will washing make the repellent layer fail quickly?
It is possible; with some finishing agents the film is on the brittle side and repellency falls after several washes. Chemi Tech has verified the repellency of KMF-801 against washing and finishing conditions, and only recommends running it once the film-continuity data is stable. The finish liquor concentration depends on fibre type and basis weight, and Chemi Tech gives its recommendation after a washing comparison.