The packaging composite adhesive has raised edges, first check from these four interfaces

The raised edges after composite should not be directly attributed to glue. This article investigates the interfaces of substrate, coating, composite, and curing one by one, helping to narrow down the scope of problems in packaging production sites.

Core keywords: packaging composite adhesive, edge warping, composite process, substrate surface Sunlife

The edge of the composite film tends to curl up after winding or before entering the next process. If the amount of glue is immediately increased at this time, it may mask the real problem and bring risks to appearance, cost, or subsequent processing.

You can investigate in the following order.

Firstly, check if the substrate is consistent. Confirm whether there have been any changes in the front and back, surface condition, storage time, and incoming batch of the same roll of material. If the problem is only concentrated on a certain batch of substrates, priority should be given to retaining the samples and verifying with the supplier.

Secondly, check if the coating is uniform. Observe whether there is a significant difference in the adhesive state between the edges and the middle, and check whether the coating components, guide rollers, and tension are stable. Edge problems may not necessarily come from the adhesive itself, but may also be related to the contact state of the equipment.

Thirdly, observe the bonding conditions during the composite process. Check whether the composite pressure, feeding status, and winding tightness are consistent with normal production. Uneven force distribution at the edges of the material may result in different bonding effects compared to the middle.

Fourth, look at the time when the problem occurred. Appears immediately after recombination, after placement, and after slitting, corresponding to different investigation directions. Matching the appearance time with the on duty record is easier to determine than just looking at the finished product.

When handling on-site, it is recommended to first fix a variable for small-scale verification, and not adjust the glue amount, speed, and equipment conditions simultaneously. For new substrates, new structures, or abnormal batches, the control samples should be retained to avoid directly scaling up production based on experience.

Sunlife can assist in selecting materials based on actual substrate and process requirements, providing sample testing, stable supply, and technical support. When communicating with procurement and process personnel, the substrate name, composite structure, abnormal location, and stage of problem occurrence should be provided simultaneously to make testing more targeted.

FAQ：

1. Do we have to change the glue when the edge is raised?
   not always. It is necessary to first confirm the substrate, coating uniformity, composite pressure, and winding status before determining whether to adjust the adhesive solution.
2. Why is the middle part normal and the edges abnormal?
   The stress, coating state, and material state of the edges and middle may be different and need to be observed separately.
3. What information should be prepared for sample testing?
   Suggest providing the substrate, composite structure, current process, abnormal photos or samples, as well as the time point of the problem occurrence.
4. Can we directly replace it with the existing product?
   Small trials or control tests should be conducted first to confirm compatibility before arranging batch use.

ending:

Breaking down the problem into interfaces for item by item confirmation is often closer to an effective solution than simply “changing a bucket of glue”. Sunlife can cooperate to complete sample verification and subsequent technical communication for the selection of packaging composite adhesive and on-site abnormalities.