How to solve the problem of poor adhesion of thin film adhesive materials？
Time:2025-05-29
Views:219
In the production process of adhesive labels, the biggest difference between thin film adhesive materials and paper adhesive materials is that their surface does not have absorbency. Therefore, when printing with UV ink, the method of instantaneous drying with ultraviolet light is usually used to allow the ink to quickly adhere to the surface of the thin film adhesive material. However, in the actual printing process, the problem of poor adhesion of UV ink on the surface of thin film adhesive materials still occurs, which brings great troubles to label printing enterprises. So, what are the reasons for poor adhesion of thin film adhesive materials? How can we solve it? Let‘s take a look at this article together.
1.Fake dryness of ink surface leads to poor adhesion
In the actual printing process, it is common to encounter the phenomenon of UV ink false drying. When testing with tape, it is easy to tear the ink off the surface of the film adhesive material. Generally speaking, there are three reasons for the phenomenon of ink false drying:
.png)
1.1 Ink layer too thick
According to the principle of ink drying, when the ink layer is too thick, although the ink surface will solidify instantly, ultraviolet light is difficult to penetrate the cured ink surface and reach the bottom layer, resulting in incomplete photochemical reaction of the bottom ink and causing false drying of the ink.
Once encountering such problems, it is recommended to use deep ink and light printing, that is, to use high color strength ink and reduce the thickness of the ink layer, which can ensure the dryness of the single-layer ink and effectively improve production efficiency.
1.2 UV lamp has been used for too long
The service life of UV lamps is generally around 1000 hours. Once the service life is exceeded, the spectral curve has already changed, and the emitted ultraviolet light no longer meets the requirements for ink curing. In addition, the increase in infrared energy leads to material deformation and ink embrittlement due to high temperature.
Therefore, during use, the usage time of UV lamps should be recorded correctly and replaced in a timely manner. In daily production, it is also necessary to regularly check the cleanliness of the UV mercury lamp and clean the reflector. Generally, only one-third of the energy of the UV mercury lamp is directly irradiated onto the material surface, and two-thirds of the energy is reflected by the reflector.
1.3 Printing speed too fast
In the production process, it is often encountered that some thin film adhesive materials have no problem with ink adhesion during normal printing, but once the printing speed is increased, the ink adhesion deteriorates.
On the one hand, the printing speed is too fast, which shortens the contact time between the ink and the substrate, resulting in insufficient connection between the substrate molecules, thereby affecting the ink adhesion; On the other hand, excessive printing speed can also shorten the UV light irradiation time, thereby reducing the energy irradiated into the ink, resulting in incomplete ink drying and poor adhesion.
Once encountering such problems, the printing speed can be appropriately reduced to allow the ink to fully contact the substrate, while allowing the ink to fully cure under UV light irradiation to improve ink adhesion.
2. The adhesion effect of different inks on the same material varies
In production, sometimes it is encountered that when using a certain ink, the adhesion of the ink is very good, but once switching to another brand of ink, the adhesion of the ink will deteriorate. This is because the type of coating on the substrate can affect the adhesion of the ink. The resin used for different types of ink may vary, so the adhesion of different inks may differ on the same substrate. Similarly, for the same ink, different substrates may have different adhesion performance. Therefore, it is recommended to conduct a thorough printing evaluation of the printing substrate and ink before use.
3. Poor ink adhesion of uncoated PE/PP film adhesive materials
We know that for uncoated PE/PP materials, it is generally recommended to use wire corona treatment because corona treatment can increase the surface tension of PE/PP materials. However, corona treatment is time sensitive and can be affected by factors such as storage and transportation environment of the material. If the surface tension of the film does not meet the requirements before printing, it will cause poor adhesion of the ink after printing. At this point, it is necessary to check the dyne value on the surface of the film adhesive material. To ensure good adhesion of the UV ink, its surface tension must reach at least 38 dyne/cm. Therefore, for equipment without corona discharge, it is recommended to purchase coated film adhesive materials.
In summary, in the actual production process, if there is a problem of poor ink adhesion in thin film adhesive materials, the cause should be analyzed correctly in order to find a solution to the problem.
Shenzhen Gold Sun Color Printing Factory is a China based book manufacturer, very good at printing hardcover book, photo book, story book, photo album, Printing paper, coloring book, packaging & printing services, Labels, printing stickers, anti-water labels, vinyl label, custom label book , softcover book, custom book printing hardcover, mini book, photobook printing, hardcover book, , board books, color sticker books, sticker books, packaging boxes for small business, custom book, children board books, kids book, journals, notebooks, Agenda, Customs Calendar, magazines, color books, cookbooks, etc. With ISO-2001 and CE certificate, Gold Sun offers very good price and outstanding service.
Welcome contact us through admin@goldsunprinting.com or add whatsapp +86 13802583954. Thank you.
Email
008613802583954
whatsapp