Our problem is your savings. We have a batch of 1 oz roll-on that has a frosted look to them. The following challenges cause this. This issue is not common but does happen from time to time. We are offering a reduced price on this item to make up for the problem. Please find the following information as an explanation.
Explanation for light white powder (like frost or crystallization) appearing on the surface of clear molded glass container, USP type III
To whom it concern:
Regret to hear that your customer found that there is light white powder like frost or crystallization on the surface of CLEAR TYPE III moulded glass container, in the glass industry, we call it “glass spit alkali”, this phenomenon occurs mainly in the hot summer months, especially in the type III glass, because the alkali (Na+, K+) content of type III glass bottle is relatively high.
The following is our type III amber glass bottle’s composition, expressed as oxide percentage:
The above element is safe for health, we also made the test for the release of heavy metal, we hereby certify that the release of Arsenic (including heavy metal lead) from the glass containers is in accordance with the specification of USP 38, EP8.0 (limit is less than 0.1ppm) and Chinese SFDA norms.
What’s root-cause of light white powder like frost or crystallization on the surface of glass container, we hereby make the following explanation. Because,
1. The reaction between the glass surface and aqueous phase (water or water vapor) involves ion exchange between hydrogen ions and alkaline ions in the glass and diffusion of water into the glass. This results in hydration of the glass surface and an alkali depleted, due to the air with carbon dioxide, the carbon dioxide reacts with water, the bicarbonate ions catch sodium ions, with the passage of time, forms the sodium carbonate crystals with water or without water.
2. Reaction between glass + water + CO2
H+ + Na+SiO-(glass) => SiOH + Na+
H2O + Na+SiO-(glass) => SiOH + Na+ + H+
H2O + CO2 <=> 2H+ + CO32-
2Na+ + CO32- => Na2CO3 (white powder)
Na2CO3 + 10H2O <=> Na2CO3 *10H2O (white powder)
SiO2 + 2H2O <=> H4SiO4
H4SiO4 + OH- <=> H3SIO4- + H2O
H2O + Si-O-Si <=> 2SiOH
2SiOH <=> Si- O-Si +H
3. So the light white powder like frost or crystallization is the mixture of Na2CO3, H2O etc. This mixture is easily soluble in the water, these substances are harmless to human body.