Due to the special application mode of in mould labels, there are certain requirements for the characteristics of labels, which are summarized as follows.
1. The label should have a certain stiffness to ensure that the label will not bend or deform during the transfer process.
2. The labels cannot be adhered to each other to ensure that the manipulator only absorbs one label at a time. There are two things to ensure this performance.
(1) There should be no static electricity between labels, which means that the surface of labels should be absolutely free of static electricity.
(2) The surface of the label, especially the printing surface, must be smooth, so that the top one of a dozen labels can be easily removed without lifting the two together, just like a deck of playing cards.
3. The edge of the label should be clean and tidy. Neither the printing surface nor the solid adhesive can be damaged, let alone two or more pieces of adhesive sticking together. For this reason, there are certain requirements for the die-cutting process of labels.
4. Due to the high pressure and high-temperature test of the ink and varnish during the label application process, there are certain requirements on the heat resistance and colour stability of the ink and varnish as well as the firmness of the ink layer.