Why Doesn’t Glue Stick To The Inside Of The Bottle?

Glue, no matter what the type, works following the basic principle of evaporation.

In most cases, stationery glue contains sticky polymer compounds dispersed in water.

Only when it comes out, the water evaporates, leaving only the polymer to jump into action. Otherwise, it remains in a non-adhesive state inside the bottle.

Superglue works in a counterintuitive mechanism, though. The Cyanoacrylate needs ambient water vapor to form cross-linked bonds.

But since the bottle itself is airtight and free from moisture, it can’t stick to the inside of the bottle either.

Let’s dig into even more details about why doesn’t glue sticks to the inside of the bottle.

There will also be some other interesting takes about the topic in this article. Read along to know more!

How Does Glue Work?

The basic principle behind glue sticking is cross-linking. It’s a scientific phenomenon where the molecules within adhesive materials interlock within one another—the better the adhesiveness, the better the bond.

But what causes this interlocking to take place?

The reason lies within the difference between the two components of any regular glue. Besides the usual adhesive component that sticks, the glue has another component called the solvent.

The solvent, usually water, keeps the glue dispersed within its container so that it remains liquid or paste.

Whether the adhesive component will jump into action by sticking or stay dispersed without sticking solely depends on the interaction of solvent with air.

In a nutshell, the solvent component comes in contact with air once the glue is outside the bottle and molecular cross-linking occurs. After that, the solvent water usually evaporates.

That’s when the adhesive portion activates and hardens the sealant to form a strong bond.

What Happens Inside The Bottle Or Tube Of Glue?

So far, we’ve talked about what happens once the glue is exposed to air. That’s how the glue is designed to work – after it’s out of the bottle, not before!

But what about when it’s inside the bottle? What happens then?

White glue or super glue are both stored in airtight containers. Unless the lid of the bottle or tip of the tube is kept open for an extended period, the adhesive component cannot contact air.

Evidently, the glue cannot participate in cross-linking or chemical adhesion or whatever scientific phenomena it’s designed for.

As a result, the glue essentially fails to work as intended and stays non-sticky as long as it’s inside the bottle or tube.

In other words, the glue isn’t exposed to air, and it cannot jump into adhesive action. Simple as that!

Why Doesn’t White Glue Or PVC Glue Stick To The Inside Of The Bottle?

Like we discussed earlier, white glue works on the principle of cross-linking.

As a result, once exposed to air, the adhesive component starts to harden, and the solvent component evaporates away.

But when white glue is inside the bottle, there isn’t nearly enough air to allow cross-linking to occur. As a result, the sealant remains intact and does not stick to the internal surface of the bottle.

Why Doesn’t Super Glue To The Inside Of The Tube?

Superglue has a slightly different working mechanism than typical PVC glue. The stickiness of the adhesive Cyanoacrylate is initiated once it’s in contact with ambient water vapor.

So, the tubes of super glue are made with extreme caution under airtight conditions.

Once they are packaged in tightly sealed tubes, you can rest assured that there isn’t the slightest hint of water inside.

As a result, the Cyanoacrylate cannot participate in chemical adhesion, preventing any stickiness or hardening. Evidently, the super glue cannot stick to the internal surface of the tube and remains intact.

What Happens If I Keep The Glue Open For Long?

By now, you have probably understood that all types of glue, whether white or super, works by exposure to ambient air. If there is no air in contact with the glue, it will remain non-sticky inside its bottle.

The safest option is to keep any glue stored under dry conditions not to be directly exposed to air or water.

It’s best to reseal the lid or recap the tube of glue right after use to prevent unwanted hardening of the adhesive.

If, however, you keep the bottle of glue open for too long, the glue particles will get in contact with air and start to stiffen. This will render the glue useless after a certain while.

This is especially true in the case of superglue, as it will begin to harden even with the slightest trace of water vapor leaked into the tube.

Therefore, it’s strongly advised not to keep the glue open for too long after use.

Next Read: How Long Does it Take for E6000 Glue to Dry

How Do You Keep Glue From Getting Hard?

Like we said earlier, it’s advisable to keep the glue container sealed at all times when it’s not in use. Otherwise, the ambient moisture will react with the bottle’s contents and end up hardening the glue.

As added steps to keep glue from getting hard, you can keep the bottle stored inside a Ziplock back and leave it in a cool, dry shelf or drawer away from direct sunlight. The fundamental trick is to avoid exposure to moisture.

So, a good idea is to introduce little silica gel packets into the Ziplock bag that absorbs ambient water vapor. 

The most extreme step you can take is to use a vacuum sealant to completely seal off the glue lid.

This is only advisable if you want to store the glue for a long time and keep it from getting compromised by getting hard.

Bottom Line

Glues are like the magical healers of the crafting world.

Whether it’s a crack you want to fix or two pieces you wish to join, the glue has your back. It’ll help you stick two surfaces with a strong bond.

And now you know the answer to why doesn’t glue stick to the inside of the bottle, along with a scientific explanation.

We hope you will use this knowledge to use glue more efficiently and prevent any unnecessary wastage.

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