Potassium perchlorate ate it's shipping bag (plastic)

[MrB]

I bought a couple of bags of KClO4 extra, to make sure to have some when a rainy day comes. Generally speaking, i get it out of the bags and in to labeled storage jars, simply since it's a lot easier to handle. But the reality is that i simply don't have enough jars for an extra 50 kilos of perch, and so i simply put the bags on a bit of cardboard, on a storage shelf in the 20' container i use for chemical storage.

Today it was time to "do things" in there, (cleaning house, verifying inventory) and as a step of that process i moved things around, but everything ground to a halt when i tried to move the KClO4. The outer bag is some weird kind of woven white plastic, there to provide structure i suppose, and the inner bag is a clear plastic. At first touch the woven stuff simply fell apart which made me sort of step back, and try and figure out what was going on before i went any further. I pretty much figured i couldn't leave it where it was, and as it was, so the scramble for substitute containers started.

I generally use 1,5L HDPE containers for all my oxidizers, but as i said previously, i simply don't have any more on hand. So i went to my "metals and organics" jars, which are clear PETE jars, other-ways identical 1.5L wide-mouth jars. A bag needs 12 jars, so i knew i had enough on hand, and could, at least temporarily, transfer it to the jars. Went to try and slide the top bag of the shelf, so i could move it to my work table, and the plastic bag ripped. At which point a complete rescue mission started. I had to sit on the floor, and try to scoop the very chunky KClO4 in to my jars, and let me tell you... it took hours. Cramped space and the heat... damn.

 

Anyway, rescue mission completed, i had some losses, but thanks to the cardboard none of it ended up on the floor of the container. Took the plastic bags outside and examined them in the bright day-light. Well, not the white woven stuff, it simply disintegrates on touch. But the clear plastic bags were somewhat "bag-like" but there was no real structure to them any more. Examining the stuff that was never in contact with the KClO4, and comparing to the very weak part of the bag where it was in contact, it's clear the plastic have been damaged. A lot. I suppose it's the "oxidizing" factor of KClO4, and that one shouldn't be that surprised, but i didn't expect this. Not really sure what happened, or how. My thinking is that the plastic used should be resistant to KClO4, since it's the factory packaging, but clearly i had an issue.

 

So, that's perhaps somewhat of a warning to people storing oxidizers. Check your containers.

But this wouldn't be a complete thread without me asking another one of my patented dumb questions. PETE is somewhat chemical resistant. The original reason for using HDPE for oxidizers, and PETE for "everything else" had simply with visibility, to do. It made sense to use clear plastics to make it easy to identify "some" materials. But at this point i'm wondering if the PETE will survive the KClO4 contact. Anyone that has any input on this, and feel like sharing? I'm quite sure it will be fine for at least a couple of months, but considering my current usage, it might remain in them jars for years on end.

 

Thank you all for your time.

B!

[Mumbles]

Most plastics should be quite stable toward perchlorate.

 

When you were cleaning all this up, did you notice any odd smells? Perhaps something that smelled like chlorine or bleach? I'd lean toward contamination or break down as the real cause.

[OldMarine]

I wonder if the bags were affected by UV exposure. Polyethylene doesn't take well to sunshine, neither do many packaging plastics.

[MrB]

Most plastics should be quite stable toward perchlorate.

 

Well, that is good considering my main concern at this point. The PETE should be fine for long storage then...

 

 

When you were cleaning all this up, did you notice any odd smells? Perhaps something that smelled like chlorine or bleach? I'd lean toward contamination or break down as the real cause.

 

Nothing really. But the container is quite well vented, so i'll give it a couple of days, and then pull the lid of some of the jars, and see what i can smell.

 

 

I wonder if the bags were affected by UV exposure. Polyethylene doesn't take well to sunshine, neither do many packaging plastics.

 

Of the top of my head i'd have to say "no". The container is in bad condition for sure, but it's still a mild steel construction. I cant see UV light getting through, and the air-vents shouldn't let any light near my storage shelves.

 

 

 

Could heat, as in temperature variations, be the cause? The container isn't force ventilated, so on days with low winds, and lots of sun it gets quite hot.

In the winter i close down the ventilation to keep the moisture out, and the strategy seams to work, everything looks dry, and what little does get in, is gone for sure after a few weeks of summer.

 

B!

[lloyd]

Reasonably pure KClO4 does not eat polyethylene at normal temperatures -- even over years of storage.

 

Oxidizers should be stored at room temperature. So long as they are shelved physically separated from fuels (by a few feet horizontally), oxidizers present no 'special hazard' that should require that they be stored in a metal shipping container.

 

Chinese chemicals are rife with contaminants that may be liberated at higher temperatures.

 

Lloyd

[MrB]

Reasonably pure KClO4 does not eat polyethylene at normal temperatures -- even over years of storage.

 

I take that as a good thing. To bad it's not exactly room temperature, year round. It goes to just above freezing in the winter, and to uncomfortably high in the summer. Nothing i can do about that outside of replacing the container with a refrigerated one, which just wont happen. Cost would be prohibitive, for one thing.

 

 

Oxidizers should be stored at room temperature. So long as they are shelved physically separated from fuels (by a few feet horizontally), oxidizers present no 'special hazard' that should require that they be stored in a metal shipping container.

 

I think you misunderstood me. I probably haven't been very clear. I store all my chems in a 20 foot shipping container. Something like this one, only, beat up, rust-red, and minus the eye candy. (I googled and got that picture in the first 3. I wonder what kind of shipping company feel like they need eye-candy to help with shipping sales...)

It's just a means to keep the wind and weather out, while still having a reasonably secure structure that i can lock, and leave unsupervised. I have a second one, admittedly the one in better shape, for storing my "gear", and a wood shed for working in. Both are way more space then i need, but in placing them in a V with the shed in the "opening" i made a security barrier as well as got storage, and they were already in "my" possession. The work shed disassembles and fits in to them, if need be, so i'm kinda mobile to, i suppose. It wasn't a factor when i planed things, but i tear down the shed for winter storage, and pretend that it will remain usable for longer with less maintenance.

 

 

Chinese chemicals are rife with contaminants that may be liberated at higher temperatures.

 

Having no idea where the perchlorate originated, all i know is i bought it from a polish pyro shop. I never had any issues with it, nor heard of anyone else having issues, but that doesn't really mean anything. I'm going to assume it falls in the "reasonably pure" category as it helps me feel better about the forced choice of storage containers. ;- )

It's stated purity is 99.7%.

 

Thank you all for your input.

B!

[Davidg1]

Likely UV damage. This used to happen in a factory where I worked when pallets of salt were stored outside. This in the UK where we don't get much sun. Edited May 11, 2016 by Davidg1

[dagabu]

Reasonably pure KClO4 does not eat polyethylene at normal temperatures -- even over years of storage.

 

Oxidizers should be stored at room temperature. So long as they are shelved physically separated from fuels (by a few feet horizontally), oxidizers present no 'special hazard' that should require that they be stored in a metal shipping container.

 

Chinese chemicals are rife with contaminants that may be liberated at higher temperatures.

 

Lloyd

 

+1

[Peret]

I wonder if it was a chemical in the shelving? Are the shelves particle board?

 

I left a new, sealed, gallon container of bleach in the garage on a particle board shelf for about a year, and when eventually I took it off the shelf the container was leaking. I'll never forget, because it leaked all over my favorite black shirt. There was a ring of corrosion on the shelf where the container had been touching it - not bleach corrosion, because it didn't smell of bleach and the container didn't start dripping until I picked it up. I figure some kind of reaction between the plasticizers in the container and the (probably formaldehyde) glue used in the particle board. Now I put a sheet of foil under plastic containers in the garage and haven't had any more incidents.

[MrB]

It is particle board, but it's foliated, (the nice shiny surface covering it to make it easy to clean) and i had that cardboard sheet in place which was undamaged.

At this point i have no idea what happened, but i left a "home climate recorder" in there to keep a bit of track of highest / lowest humidity, and temperature. I suspect i'll see at least 50c during the summer, but i have no idea on humidity.

B!

[lloyd]

From experience, I can tell you that it doesn't attack PE in decades.

 

Lloyd

[MrB]

Well, it's all been screened and transferred to HDPE containers. I cant find any foreign particles, it's all dry and free flowing at this point. I decided to dedicate it to binary-flash, and use a undamaged bag for colors. If i wasn't unable to get more, i would consider getting rid of it... But since i'm not really that much of a chem-head i don't really have the proper means of testing it, other then through pyro, where it works as expected... Still not sure what happened, or why, but it is what it is.

B!

[lloyd]

Maybe they were vinyl bags, rather than PE; hmmm?

 

Lloyd

[MrB]

Clear plastic, apparently heat-sealed, straight from the manufacturer, in a "woven" white bag sewn together. I suppose the woven bag is adding strength, and protection vs the elements, and provides a printable/stampable surface for the information on the bag.

B!

[lloyd]

Vinyl can be clear, can be heat-sealed, and can be over-wrapped with anything you choose.

 

Lloyd

[patsroom]

Well, it's all been screened and transferred to HDPE containers. I cant find any foreign particles, it's all dry and free flowing at this point. I decided to dedicate it to binary-flash, and use a undamaged bag for colors. If i wasn't unable to get more, i would consider getting rid of it... But since i'm not really that much of a chem-head i don't really have the proper means of testing it, other then through pyro, where it works as expected... Still not sure what happened, or why, but it is what it is.

B!

If you had the time and patience with the right equipment you could re-crystallize the produce to remove the unwanted material the may be in the potassium perchlorate................Pat

[MrB]

If you had the time and patience with the right equipment you could re-crystallize the produce to remove the unwanted material the may be in the potassium perchlorate................Pat

 

Yeah, i thought about that. I currently don't really have the proper space, or equipment, and truth be told i doubt there is really any contaminant in it now, that there weren't before the bags disintegrated, and i'm not entirely certain that i would be able to process it to a better purity. It's certainly pure enough for anything in the veline color system, but it just feels better not to handle it as much, so, binary flash, it will become. Both up's and down to that, since i've gone over to KNO3 based flash entirely, to make my supply of KClO4 last longer... Best laid plans, and all that...

B!

[a_bab]

Nowadays poly bags are often purposely made so they fall apart in a year. No UV is needed for this process, but the heat helps.

 

More on the subject here: https://en.wikipedia.org/wiki/Oxo_Biodegradable