Having a film adhesive label that keeps curling up while flexo printing is quite frustrating. However, what may cause it? There are several possibilities that can explain why your label keeps curling up in printing below.
1. Factory environment humidity
The film self-adhesive material is a composite material whose surface material of the film material is a film, and substrate is usually paper. The film material is unfolded during printing, so that the material is completely exposed to the air. It is assumed that the moisture in the air is not in balance with that contained in the material backing paper. In this case, the material backing paper loses or absorbs moisture to balance the moisture in the external environment. During this process, the area of the backing paper may change drastically (longer or shorter). At the same time, the surface material is a thin film, which does not change during this process, causing two surface materials, one with the same area and one with a sharp change, resulting in curling of the material. Usually after the material is die-cut, the tension between the material and the backing paper will be balanced. Therefore, when using a flexographic printing machine to print film labels, you’d better complete printing and die-cutting at one time to reduce intermediate links.
2. UV heat influence
The UV in a label flexo printing machine emit a lot of heat. When the film material passes through the UV, the backing paper will dry out and lose water rapidly. After leaving the UV lamp, due to environmental influences, the backing paper will absorb water rapidly, and the material is easy to curl and deform.
3. Static electricity influence
During the printing process, the film material will rub against the equipment, which will generate static electricity and make the materials adhere to each other. If the label is a single-cut sheet product, due to the electrostatic adsorption during printing process, the material will curl, resulting in uneven rewinding. In this case, it is effective to equip the flexographic printing machine with an electrostatic device.
If you need any help with label projects, Raloyal, the leading China flexo printing machine supplier, would be happy to offer you the most suitable solution for your label printing, die cutting and slitting. Please fell free to contact us!