Testing Polyester Fabric for Dye Migration – Part One
Ok, you have a shirt and it has some or all polyester content, what do you do? Too many printers I see P & P it. “P & P” is what I call “print and pray” and no matter what religion you do or don’t follow, I would keep prayer out of your printing operation. You need some science and here it is. You can test the fabric and get some idea of what the appropriate measures will be to print the fabric properly.
Can’t you just ask the garment manufacturer how to print their fabric? No, usually not. They just make the garments, and most leave it to you to figure out how to print it. That is changing and two of the companies we work with, Hanes and San Mar both are working increasingly to give the printer the information they need to properly print their garments. However, most times you are flying blind in the realm and there is a great deal at stake. If you print even fifty nice red hoodies and two weeks later the red dye gets into the white ink and turns it pink and the customer returns them, that has a hefty price tag. Make that 10K hoodies and you are financially ruined…
Dye migration is when the color or some part of the color in a garment migrates into the ink you printed. There are measures you often can take to stop this process, but first you need to know if it is going to happen and if so how badly. You can do a test to see what you are dealing with and that is where we will start our series on printing on polyester.
Here is the test in words and then followed by some photos.
- Put the fabric you are going to test on transfer machine. Make sure the transfer machine has been turned on long enough to be fully warmed up.
- Apply a quarter size spot of plasticizer. We use Rutland non curable viscosity reducer. Basically you want only half of the plastisol equation, all plasticizer, no resin.
- Lay a piece of white cloth or pellon on top of the plasticizer.
- Heat press the white fabric on top of the fabric you are testing. Do it at 320 F (160 C) for 30 seconds.
- Check the white fabric. What does that stain look like from where it was on top of the plasticizer. The more stain present on the white fabric the more severe the dye migration you will get when you try to print that fabric.
- All polyester dye colors will migrate at least a little bit, this test just lets you know how severe the dye migration is going to be.
- Test some fabrics you have printed before. Since there is always at least a tiny bit of migration, you need to get a feeling for how much stain is indication of how bad the migration is going to be. If you do this testing often enough and see how things then print, you eventually get a very good idea of how badly any particular fabric is going to have a dye migration problem and you can take the appropriate measures.