Is the adhesive label paper firmly attached with hot melt adhesive particles? A rectification case of label detachment

Case Background

A printing factory that produces daily chemical bottle stickers, usingHot melt adhesive granulesStick the self-adhesive label paper to the side seal of the paper box. After one week of storage, it was found that 3% of the labels had curled edges and fallen off. At first, they thought it was due to insufficient viscosity of the adhesive particles, but after changing to a higher viscosity model, they continued to repeat the process until they finally identified the real reason.

troubleshooting process

The technician first tested the adhesive particles themselves: the peel strength was normal, ruling out any issues with the adhesive. Turning our attention back to “self-adhesive label paper” – this type of material comes with pressure-sensitive adhesive on the back and is often covered with a silicone oil isolation layer on the front. Its surface energy is extremely low, and hot melt adhesive cannot wet it at all, which means that the adhesive only sticks to the silicone oil layer and naturally falls off when touched.

solution

• Replace with label paper that has been surface treated, or perform plasma or corona treatment before veneering to enhance adhesion.
• Change the phrase ‘hot melt adhesive particles directly attached to labels’ to’ adhesive only seals box seams, labels are positioned with specialized adhesive labels’, and each person should perform their own duties.
• I tried Guangzhou Sunlife TradingSunlife Hot Melt AdhesiveThe packaging sealing series has stable adhesion to the paper box body, and the label no longer falls off under force after the box seam is sealed firmly.

Key points for review

FAQ

Q: Can’t all label papers stick firmly?
Answer: No, regular copperplate stickers can stick, but those with silicone oil isolation layers are difficult to stick. Please check the materials before placing an order.

Q: How to avoid pitfalls in small-scale trial pasting?
Answer: First, take the sample and conduct a 48 hour static and light pull test, then enlarge the goods. Don’t wait until they are stored to discover the problem.

This case reminds: If the label falls off, don’t rush to change the adhesive. First look at the surface of the material – if you stick the wrong object, even the best adhesive will be useless.