If you work with labels, you know how important it is to deliver an end product where the labels are applied perfectly. There's no down-time to stop and worry about label staining or discoloration.
Today we dive into some simple ways to troubleshoot an issue like this.
Possible Cause: Oil or Grease from Equipment
Rule one: always take the time to make sure your equipment is clean and running properly.
If your equipment is running dirty, you will be exposing your substrates and glue to contaminants. This could result in stained or discolored labels, and lots of money wasted.
Possible Cause: Thin Label Stock
If you're working with extremely thin label stock, you could be experiencing label staining or discoloration.
Your first course of action should be to apply a thinner glue film to the substrates. Speak with your glue vendor to find out appropriate glue film thickness for your project. If you find that a thinner glue film does not offer the desired adhesion, you may need to adjust the label stock.
Possible Cause: Highly Absorbent Labels
This probably seems like an obvious one, but if your labels are highly absorbent any moisture (including glue) that you apply to the label could result in staining or discoloration.
It's always best to let your glue supplier know exactly what type of label stock you are working with so they can recommend the best glue for your specific application.
In this case, you'll want to use a low penetration glue to limit any staining.
Possible Cause: Excessive Glue
People are always surprised to hear us say this but, you should never apply more glue than necessary to your substrates. Each formula has a recommended operational minimum, and it's best to stay at or under that recommended glue film thickness.
If excessive amounts of glue are applied to the labels, you could run into issues with discoloration, curling, smearing and misalignment.
Possible Cause: Glue is Contaminated
Glue contamination is another possible cause for label discoloration. Always make sure you are using glue that is: not contaminated with mold, dirty, frozen, or beyond the shelf-life.
Possible Cause: Ink, Metallization Water or Alkali Sensitive
This one comes back to letting your glue supplier know any special features or restrictions of your application.
Selecting and using the proper glue formula will help to avoid any label staining or discoloration caused by ink, metallization water or alkali sensitivity.
If you are still running into issues after putting these suggested solutions into action, we're always happy to help. Contact our technical support team today!