Teach me about modern labeling adhesives
December 24, 2017 12:04 AM   Subscribe

This ask from 2010 gets after what I'm curious about: When I was growing up, soaking a glass jar or bottle in warm, soapy water generally sufficed to de-adhere the label and remove (at least most) of the glue from the vessel. Lately, though, this seems just to disintegrate the label and leave a tacky, gunky residue. What changed?

It seems that, like with so many things, a plant- or animal-based product in the adhesive (collagen? casein?) has been replaced with a petrochemical (acrylic? urethane?). Is that correct? If so, why?

Is it for better thermal stability, so the vessels can be heat-processed after the label is applied? Are the new compounds more consistent with regards to process properties/quality? Are they simply cheaper? Do they work against a wider range of label materials, like the vinyl that seems to be lately common? Do they cure faster? Come to think of it, how do they cure? Do the people who make these decisions just hate the home canning/bottling industry?

I'd love if any packaging engineers or chemists on the site could answer any of these questions for me. There's lots of anecdotal info out there (v.s.) as to how to remove the stuff (canola oil! hair dryer! ice bath! hexane!) but after battling it for a few hours earlier tonight, my bleeding hands could use a more sciencey explanation.
posted by 7segment to Grab Bag (16 answers total) 14 users marked this as a favorite
Is that correct?


If so, why?

Process convenience, mostly. The new-style labels are pre-coated with the same kind of adhesive you find everywhere on stickers now. They don't need separate glue application and label application steps, and they also don't need time to cure because the full bond strength is already present as soon as they're applied to the glass.

And as you've found out, the new glues are in no way water soluble. They're also annoyingly good at retaining at least some semblance of cohesion even when hit with assorted non-polar solvents like oils. Hexane works better, but it evaporates so fast that you always end up with tacky patches wherever the hexane-diluted glue has run to. Plus it smells bad and is bad for you.

Fortunately, all the self-adhesives do weaken substantially with heat. The hair dryer method is not too bad, but as well as uneven heating making the glue stay firmly stuck in annoying patches, you end up fighting against the fact that applying hot air inevitably makes the outside of the glue layer hotter than the inside; it's really the side nearest the glass that you want to weaken more, so that the glue's fairly extreme cohesive powers will help it come away with the label rather than detaching from the label and staying on the glass.

Best label removal method I'm aware of for modern self-adhesive labels involves filling the jar with hot water while taking care to keep the label dry, screwing on the cap, then peeling off the label after the glass has had enough time to get uncomfortably hot to the touch. You will pretty quickly work out just how hot the water has to be for any particular variety of label you commonly need to remove.
posted by flabdablet at 12:28 AM on December 24, 2017 [47 favorites]

I remove labels AND the adhesive easily with rubbinging alcohol these days. Just let it soak for 5 minutes.

My advice works and it's different from the methods flabdablet mentioned, I hope it's OK I posted. I know you did not specifically ask for removal methods, but I felt compelled to chime in because you seem to have struggled quite a bit + missed the one piece of internet advice that works. Just let it soak for a few minutes, then the adhesive scrapes off easily.

Like you, I noticed a difference a few years ago and went on a quest. Thanks for being more intellectually curious than me, this was informative!
posted by jbenben at 4:31 AM on December 24, 2017 [3 favorites]

I too hate removing modern labels so I investigated this. I was looking for old fashioned mucilage to stick labels on homemade foods and drinks and found it online but not locally. Aloe was mentioned as a source and I happened to have a pint jug of the stuff so I experimented. It seems to stick really well and isn't too hard to remove but I don't It has only been a few days so I don't know how long it will hold.
This may also be tangential but if you can or brew you could do more extensive experiments. (Just make sure to get
the gel all the way to the edge of the label.)
posted by Botanizer at 4:57 AM on December 24, 2017

Pretty much flabdablet's use heat. I add razor blades, the No. 9 single edged ones. After the hot water, if you press hard enough on the razor blade it will curve a bit and hug the bottle and you can scrape off 3/8" or so strips pretty easily. You can do it the other way around and just scrape off the majority of the label and glue when it's cool and dry and then do the hot water and give it a second go.
posted by zengargoyle at 5:24 AM on December 24, 2017 [1 favorite]

I've had luck with GooGone.
posted by tilde at 5:28 AM on December 24, 2017 [3 favorites]

If the water's hot enough, you can pick one corner free and then pull the rest of the label off in one piece. Just don't pull too fast or it will tear.

The hotter the water, the less grip the adhesive will have and the faster you can pull off the label; but the heat reduces cohesion as well as adhesion, so if it's hotter than it needs to be, you'll get more glue residue left on the glass than you need to. I generally find that water hot enough to require two layers of tea towel to hold onto the hot jar is adequate. If it's hot enough that I need a potholder, the glue will be annoyingly loose and tacky.

Small spots of residue can be picked up by sticking bits of the label back onto the glass over them; the hand action is more sticking the label at the glass than on it, if that makes sense. It's the same action you'd use for getting lint off clothing with sticky tape.

With a bit of practice, this method gets labels off jars quite quickly and with nothing to clean up afterwards but the discarded labels themselves.
posted by flabdablet at 5:43 AM on December 24, 2017 [2 favorites]

On some pickle and other jars, the papers is only adhered at the ends, and is gunky and impossile to remove. I have no solution for removing that. If a plastic label doesn't come off cleanly and leaves a residue, I smear it with a bit of oil, whatever's handy in the kitchen, and let it sit, then scrub off with a paper towel. I admit that I have a big laundry basket of jars in the shed, but the labels are off.
posted by theora55 at 7:23 AM on December 24, 2017

that egregious grammatical error is due to bad typing. the *paper* is.
posted by theora55 at 7:57 AM on December 24, 2017

Y'all need to try the rubbing alcohol method, it works every time on modern label adhesive. I swear!

Saturate a label, let sit for 5 min, scrape it off w/ the back of a bread knife or metal scrubbing pad. Hardly any pressure required.
posted by jbenben at 8:01 AM on December 24, 2017 [2 favorites]

Is it for better thermal stability, so the vessels can be heat-processed after the label is applied? Are the new compounds more consistent with regards to process properties/quality? Are they simply cheaper? Do they work against a wider range of label materials, like the vinyl that seems to be lately common? Do they cure faster? Come to think of it, how do they cure?

There are essentially infinite types of adhesives, so you are right about all of these things in at least some applications. Heat processability is very important, especially for food applications. The ability of the adhesive to resist temperature changes which cause adhesion failure was a big driver in the beginning. Temperature changes also led to condensation, which also caused delamination but more importantly led to label deterioration (paper and/or text failure). Circumventing this problem requires new label materials (like vinyl, plastic- coated paper, metallic, etc.) which in turn requires new adhesive technologies. Glass, too, has changed over time, particularly surface roughness (or even added coatings), which necessitates more advanced adhesive technology.

There are a lot of different types of curing, often using light, heat, and/or pressure. It depends on the chemistry used and also on the application. A substantial subset of labels are essentially stickers (pressure sensitive adhesives) like you could buy at the store, but these types are generally less robust. Most animal derived adhesives fall into the “sticker” category. Stickers are typically less complex to apply (you could do it yourself at home), but more susceptible to user error (sticking to itself, positioned incorrectly, etc). Labels with newer adhesives can often be repositioned, applied via robot, cured on demand, tailored to meet specific adhesive strengths, and more. And yes, they are meant to be more consistent in performance and processability, as you mention. Even things like the color of adhesives can become important (don’t want a brown adhesive showing through a pretty white label!).

Regarding removal: there is no universal method. The chemistries are so diverse that some require very non polar solvents (hexanes), some very polar (alcohols), and some won’t dissolve in any solvent. Razor blades are usually required regardless. Heat helps, or sometimes cold helps, or sometimes both.
posted by chemicalsyntheticist at 8:03 AM on December 24, 2017 [3 favorites]

Here's a training video and a promotional video that together will give you a pretty good idea of how self-adhesive labels end up on containers. As you'll see from those, the mechanism is a great deal simpler than that required for glue-on labels.

Warning: this is a YouTube rabbit hole at least as deep as the industrial shredding machines one.

Here are the adhesives offered by the manufacturer of that last machine. Note how they point out that cleaning their wet adhesives off the machines can be done with lukewarm water, which leads me to expect that these glues would also succumb to soaking when removing labels at home.

Self-adhesive labels use pressure-sensitive adhesives and are supplied on a waxed paper backing tape. The adhesive never actually comes into contact with the machinery, only with the backing tape and the containers, so it doesn't need to be easy to clean off things.

On some pickle and other jars, the papers is only adhered at the ends, and is gunky and impossile to remove. I have no solution for removing that.

That's hot melt adhesive. On glass jars I use the hot water fill method to get the label off initially, then an ice water fill to make the adhesive residue stiffer and less tacky, at which point it can be scraped off with a sharp knife. When it's cold, it behaves more like Blu-tack than chewing gum.
posted by flabdablet at 8:04 AM on December 24, 2017 [1 favorite]

On the other side of this, if you want to make home made labels that come off, use diluted Titebond glue, red. The Titebond blue is not soluble in water. Titebond is standard carpenter's glue. I have adhered many a wine label with Titebond Red. Just use the minimum.
posted by Oyéah at 11:22 AM on December 24, 2017

The method for removing modern labels that's worked best for me is:

1) soak the label in hot water until it softens & then peel off / scrape off as much as possible
2) let the jar & remaining adhesive dry
3) spray a paper towel liberally with WD-40 and rub the remaining adhesive off
4) re-wash the jar to get rid of the WD-40 residue

Warning: WD-40 is poisonous so this is not the best method to use for containers you will be using to contain food.
posted by Secret Sparrow at 11:57 AM on December 24, 2017

California scents citrus aresol removes labels very nicely if you spray on a good coat and let it sit a bit to soak in as long as the outer portion of the label is paper. Occasionally, a second application is needed for the final glue residue. And it smells nice!
posted by mightshould at 5:43 PM on December 24, 2017

A long soak in hot water and Oxyclean, and then a scrub with a melamine sponge to get the last stubborn bits off.
posted by elsietheeel at 6:39 PM on December 24, 2017

One of the most useful pieces of advice I've ever had, from my slightly annoying cleaning obsessed sibling, was to spray the label really thickly with furniture polish and leave it until the sticker just...slips off. Spray from about an inch away so there is a thick foam covering the sticker. It was revolutionary.

Unfortunately, probably the only time I actually use furniture polish.
posted by ElasticParrot at 6:09 AM on December 26, 2017 [1 favorite]

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