Does aluminium bottles react with coatings based on nanotechnology?

[Richardtf]

Hi,

I am rather unfamiliar with chemistry, so therefore I hope that you are able to help me.

I am in the process of starting a distributor of nano-based coatings, due to their great beneficial elements.

As a part of the process I am naturally looking for bottles. I do know that the ceramic coatings has to be stored in Aluminum bottles. I would prefer to store all my coatings in aluminum bottles, but I'm uncertain whether or not they will react with the aluminum, and what the reaction will do. 

The coatings are water based, and made on the chemical basis "modified SiO2". The chemical stability is between pH1pH1 and pH13pH13, does that create any difference? I do recon that some of them contain a water-ethanol mixture.

The bottles I am looking at is: Chemical pesticide insecticide agrochemical pharmaceutical metal 100 ml aluminum bottles, stainless steel aluminum and regular aluminium bottles.

I have read some where that it depends on the pH value on my coatings, where they are above 3 or below 9. 
If that's the case, what will happen if it is below 3 or above 9?

My supplier told me that the chemical stability is between pH 1-13, which is close to the whole pH scale. What does this mean?

Please do ask if any further information is required, hope that someone is able to help me. Tried to do some research on my own, but without much chemical knowledge it's tough.

Kind regards,
Richardt.

[theinnertemple]

Dear Richardt,

Your question is a little confusing in that I'm not sure whether you are talking about pH stability of your silica nanoparticle coatings or the Al containers.

The one bit that does make sense is the statement about between pH 3 and 9. Al forms a passive (corrosion resistant) metal oxide between about pH 3.9 - 8.6. Below 3.9 it will form Al3+ which is soluble and therefore corrodes and above 8.6 it also corrodes. The stability also depends on the electrochemical potential of your system but I don't think that's too important here. Essentially if the material you want to store in the Al bottles has a pH < 4 and > 8.6 your bottle will corrode.

My gut feeling is that your SiO2 in ethanol/water mix is probably around pH7, but it's worth checking the coating with a piece of universal indicator. That should give you a ballpark value for the pH.

[Richardtf]

Dear Andrew,

Thank you for your answer, and sorry for my confusing question.

My question was actually based a bit on both, whether one would react with the other and the other way around.

I have done a bit of testing with universal indicator paper, and found that my coatings approximately has the values of;

- pH 5

- pH between 2-3

- pH 7.

Which would mean that the coatings with pH between 2-3, would cause my bottles to corrode?

My products will have a shelf life on around 1 year. I have tried to do a bit of research, and it says it can cause a "slow chemical corrosion". Is it possible to give an indication on when the corrosion begins, how long time there goes before it has any effect, and whether or not it can ruin my nano coatings effect?

My supplier of the Al bottles also has a bottle that they call "Chemical pesticide insecticide agrochemical pharmaceutical Alluminum bottle", does this bottle do any difference regarding the possible reaction with Al? Perhaps it corrodes at a lower og higher pH value?

Also when my supplier of the coatings indicates the products has a chemical stability between 1-13, what does that mean?

Sorry for my poor knowledge, and thank you very much for the help, i'm very grateful. 

Kind regards,

Richardt.

[WayneCook]

The key will be the pH of your product.  The nanoparticulate silicate (SiO2) should have no effect on aluminum.  However, the pH of the complete formulation will have an effect.  If the pH of your product is around 7.0 (+/- 2.0) You should not have nay problems with an aluminum bottle.  The bottle manufacturer's spec range for pH (pH=1-13) is rather large for aluminum.  

The simplest was to prove the stability of this container is to accurately weigh an empty bottle, put your product in it and warm it to the highest temp possible without boiling.  If you have ethanol in your product, you may just want to store it at about 25-30C.  After several weeks, empty the bottle, rinse it out, and reweigh it.  If the weight of the bottle has either increased or decreased, you may have a problem.  If the weight is unchanged and there no obvious appearance changes, you are probably OK with this bottle.

Hope this helps!

[FBTCOK]

We have just had manufactured a series of shampoo, conditioners, and treatments based on the conditioners at a contract manufacturer. The manufacturing went well until two months later when we have a reaction in the bottle with the conditioners. In some cases, they make a fizz sound like when you open a soda bottle and continue oozing. The Ph range is between 3.07 and 3.54 for the conditioners and 4.97 to 5 for the shampoos. The bottles have an inner coating of epoxy resin. The caps are aluminium with a double silicon wad to prevent leakage. When the bottles were cut in 1/2, the inner coating in some cases was back to bare aluminium.

The supplier is a major supplier to the personal care industry for this type of product.

The micro passed at manufacture, and we had it tested as soon as we had the issue, and it is fine.

Any input you can provide to assist with understanding what is happening and how we can fix it.

[radg]

Hello, just someone having the same problem at manufacturing.

Were you able to solve this issue with the aluminium bottle coating? If so was it the coating material which was changed?

Thanks for your help,

Reha 

[FBTCOK]

Hi Reha

The coating is the issue, but it had many problems:

• The manufacturer applied the incorrect coating. I contacted the coating supplier and provided samples and they said it did not match their reference.
• The coating was applied irregularly, so the inside was not all coated. They said they used semi-automatic coating, not 100% automated.
• The combination of the incorrect coating and the irregular manner caused a reaction after manufacture, which was when the cap was opened, the conditioner erupted like a volcano.

In the end, we could not get any resolution from the packaging supplier, so we moved to 100% recycled HDPE, which is a far better choice.

On balance, I suggest you not use aluminum packaging as it dents easily, needs additional packaging to keep it safe in transit, weighs more, and is very dirty to recycle, let alone unreliable. 

I would be interested to know who your supplier of the aluminum packaging was and what shape of bottle you used. The one we selected was not a high-demand item. I am happy to provide you with additional information if it helps your situation.

Cheers

Catherine

[radg]

Dear Catherine,

Thanks for your sincere answers. We are aiming to have the bottles reused instead of recycling them hence were really keen in using aluminium. I was just in contact with another manufacturer - eco-packings.com - where they have also informed us that automatic manufacturing is necessary for this pH level. I have been informed about the coating manufacturer -PPG- and what they use and the safety datasheet of the coating (in the attachment) - which I will be contacting them within the day. 

The manufacturer I previously have been in contact was passenpack - where they have standart bottle sizes with 100-300 ML which is what we have been looking for but we were not "happy" with their approach regarding standards and what could be used inside. We also have sample products here but did not cut them in half yet. 🙂

Our biggest - which I know it is a hard thing to run after and maybe a little too ambitious - is that plastic even though is recyclable - only 10% of it globally is recycled and mostly end in landfills and oceans unfortunately. I would appreciate any kind of extra help and information that you could provide.

Thanks for all, 

Cheers,

Reha

[Arutnevking]

Storing coatings in aluminum bottles can be suitable, but it's important to consider the potential reactions between the coating and the aluminum, especially when dealing with water-based coatings and considering factors like pH.

The pH scale ranges from 0 to 14, with 7 being neutral. A pH below 7 is acidic, while a pH above 7 is alkaline. Here are some considerations for your specific case:

pH Range and Aluminum Reactivity:

pH Below 3:
If the coating has a pH below 3 (strongly acidic), it may lead to corrosion of aluminum over time. Acidic substances can react with aluminum, forming hydrogen gas and aluminum salts, which can compromise the integrity of the bottle and contaminate the coating.

pH Above 9:
A pH above 9 (strongly alkaline) can also potentially cause a reaction with aluminum, leading to corrosion. The exact extent of reactivity may vary based on the specific chemical composition of the coating.

pH Between 3 and 9:
If the coating falls within this pH range, it is less likely to react significantly with aluminum, making aluminum bottles a safer choice.

Chemical Stability Claim (pH 1-13):

The claim that the chemical stability is between pH 1-13 suggests that the coating should remain stable within this pH range. This implies that the coating is less prone to chemical breakdown or precipitation within this pH span.
Water-Ethanol Mixture:

If your coatings contain a water-ethanol mixture, you should also consider the potential impact of ethanol on the aluminum. Ethanol can act as a solvent and may influence the reactivity of the coating with the aluminum surface.
Bottle Material:

Stainless steel is generally more resistant to corrosion than regular aluminum. If corrosion is a concern, you might consider stainless steel bottles for added protection.