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What do you call the ring left around the neck of a plastic bottle when you first take off the bottle cap? Answered

It's made as part of the bottle cap, to create the safety seal; and it breaks away from the cap the first time you open the bottle.


Thank you for the citation to the true answer (and apologies to Caitlinsdad for doubting him!). I've taken the liberty to unmark myself and select this as Best Answer.

Can you do that??? (I guess you can :). It's okay, I probably might have changed it myself (inhibited only by doubts about robbing you of Best Answerer status), but it did give me a bit of a start when I checked back in on this Question. I thought only the Question's Author could do that - is it just me and the previous Best Answerer (& maybe some of the squiddier Squid Labbies)? It's not just anybody who can mark and unmark Best Answers, is it?

An explanation of the function of the permanent ring located below the tamper ring is that it was included to provide a support during filling. A PET bottle has poor column strength (when empty) and filling the bottle with a carbonated beverage required that a seal be made so that the empty bottle could be pressurized to allow filling. Pushing hard on the top to make a seal caused the bottle to collapse, so the ring was added to hold the bottle.


I always call it: "the Ring left around the neck of a plastic bottle when you first take off the bottle cap". Or I guess You could call it Garbring or Ringbage.

As a person who was once a bottle cap fabricator, I can tell you that it's usually called a skirt or ring. It doesn't have a technical term because the ring itself is only considered in terms of "pop value" which is the measurement of the pressure that it takes to open the cap. It's not a tamper evident cap as those are generally used for milk jugs not vacuum sealed bottles(they don't have threads to screw the cap on)

I think that "tamper-proof" may have come to mean either "tamper-proof" or "tamper-evident" under the linguistic principle that usage defines meaning. (Much like "hopefully" has come to have the second meaning of "it is to be hoped" (e.g., if I say, "Hopefully, I will get to my dentist appointment on time," I probably don't mean that I intend to arrive at the dentist's office not only promptly but also in the emotional state of being filled with hope).)

Rtsaekdb's does seem to be the best answer so far (and has the added bonus of making excellent use of the word "frangible," which is something that one doesn't get to see every day :). I'm leaning towards "tamper-evident ring" as perhaps the most intuitively sensible term to be had.

You were right, I was wrong. The CCMA reference in the newly marked (by me) Best Answer is fairly well definitive.

I don't have a definitive citation, but my conclusion is that the ring left behind is called the skirt.

Following links from the Wikipedia article on bottle caps, the situation is unclear. The perforations are there as a tamper evident seal, obviously, but that's not a specific term.

In the case of wine bottles, the part that breaks away is referred to as the "skirt." I did not see that term used in the Wiki articles about plastic bottles, bottle caps, etc.

A Google search for "screw cap skirt" reveals a number of patents in which that term is used specifically for the part of the cap that extends below (and stays on) a container, regardless of type.

. I <3 your leet search skillz. You Da Man!

Dude, it's called research. I get paid for it, but usually I'm reading peer-reviewed physics papers....

. Well, I spent 3-4 minutes searching and got nowhere. I was going to wait a day and if no one came up with an answer, dig deeper - I was kind of curious myself.
. Thanks, also, for explaining how you tracked it down. I didn't make the connection between wine and soda bottle caps. The last time I drank wine, only Boone's Farm and Annie Green Springs came with screw-off caps. heehee

If I had found the answer with a simple Google or Wikipedia query, I would have been more terse, and probably more sarcastic :-/ In this case, walking through the non-obvious process is consistent with my (our :-) "teach a man to fish" approach. Following some of the references from the "wine bottle" link in my answer will lead you to the history of how screw caps have been adopted and accepted by "real vintners" and oenophiles over the past decade or so. Because of the high stability and low failure rate compared to natural cork, I've become a big fan of properly sealed screw caps.

By the way, this was an interesting question to ask, and not easy to track down.

Thanks. :) And thanks for doing all that virtual legwork to track it down - I didn't even have an idea where to start. I'm working on a couple Instructables that will involve these bottle cap skirts, and racking my brain for what to call them. There was another Question about them earlier today, and that inspired me to Ask this one.

What was the other Question? As I noted above, it was not easy (and I didn't) to find a definitive answer.

Caitlinsdad has provided some evidence that they are merely called "tamper proof rings" (which is really a misnomer, since they don't prevent tampering, just showt that it happened), but I think (don't know!) that "skirt" is the general term whether it's being used for tamper-control or not.

Ah! Thank you for the link. I am fairly confident that the other author is talking about six-pack rings, not about the bottle-cap bits (which you can't easily remove from the bottle, so why would they have a bunch just lying around?).

Oh. Right. Duh.
Six-pack rings would make much more sense in that Question.

I was trying to imagine how they might come to have lots & lots of the bottle-cap-skirt tamper-evident rings coming into their workplace, but I really didn't get very far. :)

I think the proper term is tamper proof ring. The skirt would probably refer to the flange or wall of the cap.

Yes. Skirt refers to the full extension of the cap below the threaded section. The tamper-evident feature is used on many products, but on wine bottles it seems to be just more of a "don't let the cap fall off" thing.

Left untampered, it is a "don't fall off the wagon" thing.


9 years ago

I think the term is the safety seal.

You were on the right track. See my un-bestest answer.

Safety seal is good...:D