08 TECHNICAL INFORMATION | PRODUCT SECTION
Chemical properties
The chemical resistance especially of DURAN® glass is more comprehensive than that of all other known materials. DURAN® borosilicate glass is highly resistant to water, acids, saline solutions, organic substances and also halogens such as chlorine and bromine. Its resistance to alkali is also relatively good. Only hydrofluoric acid, boiling phosphoric acid and strong alkalis cause appreciable surface removal of the glass (glass corrosion) at elevated temperatures (> 100°C). Due to the nearly inert behaviour, there are no interactions (e.g. ion exchange) between medium and glass and any spurious influence on experiments is thereby effectively excluded. Hydrolytic resistance DURAN® corresponds to Class 1 of the glasses that are divided into a total of 5 hydrolytic resistance classes in accordance with ISO 719 (98°C). The amount of Na 2 O/g glass grain leached out after 1 hour in water at 98 °C is measured. For DURAN® the quantity of Na 2 O leached out is less than 31 µg/g of glass grain. DURAN® also corresponds to Class 1 of the glasses divided into a total of 3 hydrolytic resistance classes in accordance with ISO 720: (121°C). The quantity of Na 2 O leached out after 1 hour in water at 121°C is less than 62 µg/g of glass grain. Due to its good hydrolytic resistance, DURAN® meets the requirements of the USP, JP and EP for a neutral glass that corresponds to glass type 1. It can therefore be used in an almost unrestricted way in pharmaceutical applications and in contact with foodstuffs.
Hydrolytic attack on DURAN® as a function of time (h)
Acid resistance DURAN® corresponds to Class 1 of the glasses divided into 4 acid classes in accordance with DIN 12116. As the surface removal after boiling for 6 hours in normal HCl is less than 0.7mg/100 cm 2 , DURAN® is classed as acid-resistant borosilicate glass. The quantity of alkaline metal oxides leached out in accordance with ISO 1776 is less than 100 µg Na 2 O/100 cm 2 .
Acid attack on DURAN® as a function of acid concentration
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