Once you have decided that you are going to screen print all the T-shirts & sweatshirts that you could conceivably need, whatever the reason for them may be. This basic question needs to be considered before you hurry off into retail land and journey across Richmond VA to get the possible deal on the maximum number of garments.
How to print on polyester containing fabrics?
To achieve success in screen printing an understanding of dye migration is required. A polyester fiber is generally speaking not as absorbent as cotton. So to seal the dye the ink is heated creating a chemical bond which attaches to the polyester fiber, this occurs between 230 and 260 degrees Fahrenheit.
The inks which are used in screen printing are made of a resin and an epoxy plasticizer, when these are mixed the colored ink is produced. To fully fuse into the fabric they need to each a temperature of 320 degrees Fahrenheit, which needs to be maintained for 1 minute.
The problem is that at 260 degrees the dyes which have started to bond to the polyester sublimate, they change state directly from solid to gas. A further consideration is the molecular weight of the dye; this means that for a given mass of ink, if there are larger particles (higher molecular weight) the ink particles do not mix properly and so the color is not properly dispersed through the ink itself.
The solution:
There are two basic solutions which themselves mask some very delicate and precise engineering. To stop bleeding (dye migration) a bleed resistant ink is used. This raises the question of what combination of cotton and polyester to use in the T-shirts & sweatshirts. Dye migration is always going to happen, so talk to a professional or you may find that a second expensive trip to retail heaven in Richmond VA is required.
The second point is to use inks that fuse at a lower temperature, however you need assurance that the process has actually worked properly. There is an inverse relationship between temperature and fusing, such that the lower the temperature the less likely is migration.
In summary before journeying off to get your T-shirts & sweatshirts screen printed make sure you have the right dyes, for the right garments at a price you can afford, in short look before you leap is the order of the day.
Visit Image Designers Inc. for advice on where the right T-shirts & sweatshirts can be obtained from the retail outlets in Richmond VA.
