Label peel off complaint
We are using casein glue to adhere label to beer bottle. The glue seems okay in our routien test but there are still numberous complaints of label peel off in water bath. Could anybody have idea on why it happens, please help me out!!
There are a few reasons why this may be happening. Certainly if the bottles are in ice water long enough you will have some problems. If your label stock isn't wet strength your problems will be worse.
The most common thing I have seen in the last 10 years is typical beer label glues like you are using not sticking well to the glass coatings applied to the bottle. As bottles have become more lightweight, the manufacturers have applied more polyethylene based coatings to the outside of the bottle. You then end up labeling a "plastic" bottle with a glass adhesive.
If this is your problem, you can see it very easily. Give the label about a week to completely dry. Leave the bottle at room temperature during this period. Then attempt to peel off the label. If you see areas where there is plenty of glue on the label but nothing on the bottle, you have found your problem.
The only way to deal with this is to have a hybrid glue formulated which still has the ice proof properties you are looking for but also can handle the coatings. Because this has become common, many glue suppliers have products that can help.
Interestingly, if you pasteurize your product, the water treatment found in pasteurizers can oxidize the coating which eliminates this problem. This is why most of the glass plants are unaware of the problem. The big guys don't have this problem and often ask for more glass coating.......which will compound your problem. They figure what's good for the goose is good for.....well you get it.
I'd like to hear what you find out. Cheers!
Majestic Packaging Solutions
thank you for your reply
Unfortunately, we are using glass bottle without coating. I find that label peel off only happens in few outlets and after peel off, glue is found on the bottle surface but not on the label. I am suspecting that the casein glue, when dissolved in water bath, promotes bacteria growth. The metabolite of bacteria could have negative impact on the cohesiveness of the glue. I am not sure if my theory is right and would like to ask if anybody can comment on my theory