how does iron-on image tranfer work? what factors determine how long the transferred image will not fade?

Question

I am interested in as much detail as possible on how image iron-on image transfer works (ie diy tee shirts)- what is actually happen and what determines the quality/durability of the transferred image? what makes some transfer paper higher quality than others?

Answer 1

Iron on transfers are heat laminations. They start with a release paper, a paper with a slick coating on it. Silicone is a common material used to coat release paper. Often they perform a corona treatment process on the release paper to prevent the ink from beading up.

The image is usually made with aqueous latex solutions. They can add water-based dyes and metal flakes to create the decorations. These are either silk screened on or lithographically printed onto the paper. They then heat the print, driving off the water and cross-linking the latex. Then they spray on a heat activated adhesive (polyethylene is often used). The iron-on is ready.

When you lay the iron-on to a piece of fabric, the adhesive softens and bonds to the fabric. After cooling the bond is stronger to the fabric than to the release paper. The paper pulls away.

A far as durability goes, there are many factors to be balanced. Thickness of the latex, type and thickness of the heat activated glue, type of fiber in the cloth, stretch in the cloth, weight of the cloth. These factors and more must be optimized to get high life-times and performance.