Water Proof and Water Repellent Fabric Finishes
Fabrics to be used as raincoats, umbrellas, and tarpaulins have to be treated with chemicals to give them a property which makes them water resistant. The finish is called waterproofing and it is a durable finish. Water repellant finish is different from the waterproof finish. It means water, if showered on the fabric briefly, cannot make the fabric wet.
Water Proof Finish
The waterproof finish should still be classified by a degree because of its involvement in a big duty rate difference for export to the United States.Please note the following:
If the fabric in question is a TC fabric and the waterproof finish is only a regular waterproof finish which cannot pass the Rainwater Test No. AATCC-35 the import duty is 34% for jackets. However, if the same fabric with waterproof finishes which can pass an AATCC-35 test and qualifies as rainwater resistant, then the duty is 7.6%.
To pass the rainwater test no. AATCC-35 the fabric has to go through a Cup Test where the fabric has to stand 600mm water pressure without leakage.(The laboratory can do the test for you)
Most fabric finishing mills know about the above test and the required waterproof standard to qualify for rainwater duty. The importance is to specify clearly what you need when you order the fabric.
From the above, you will see that the duty difference between 7.6% and 34 % is big. If you use the right quality of waterproof finish, you can benefit from the low duty rate. However please note that apart from the waterproof finish, the style of the jacket has to be taken into consideration too. If the styling of the jacket is obviously not to be used, and cannot be used as a rainwear, the U.S Customs may refuse to let you enter the garments as rainwear duty, although the fabric meets the waterproof standards required. The styling which may cause the jacket not to be a rainwear can be briefly noted an s follows:
- Quilting stitches are done on the outside; water can easily go to the padding through the numerous needle holes.
- With packets without flaps, water can easily go into the pockets as many pieces joined together. Water can go through the seams.
- If the jacket
Water Repellent Finish
Water repellant finish is different from the waterproof finish. It means water, if showered on the fabric briefly, cannot make the fabric wet. However, water can still get through the fabric if we continue to shower on it.
You can do a test to find out if the fabric has water repellent finish(W.R) or waterproof finish(W.P) has no finish (plain finish) on it as follows:
- Put the fabric on a flat surface and put a few drops of water on it.
- If the water rolls on it, it tells you this side of the fabric has W.R.Now you use your finger to rub on the water. If it does not get through to the other side, it means this fabric also has W.P on the other side, however, if it gets through to the other side it means it has W.R on this side only.
- If the water gets absorbed and it got through to the other side easily (Completely wet), it means the fabric has “plain finish” not W.R and not W.P.
- If the water does not roll but sticks to the fabric and when you rub on it, it does not go through; it tells you that this side of the fabric has W.P finish. Very possibly, it has W.R on the other side, because normally, when the fabric has W.P on the other side. It has W.R on the other side. To make sure what you think is correct, you can turn it over and put water on it to see if the water rolls.
- Another test: If you can breathe through the fabric, it is not W.P. If you cannot breathe through the fabric it is W.P