chemical properties    

chemical resistance

Products from the glass SIMAX feature a high resistance against effects of water, steam, acids, salt solutions, and a relatively good resistance against alkalis. For these reasons, the glass SIMAX is used in cases where high chemical resistance and neutrality against stored or processed substances are required for the products, i.e. in chemistry, laboratories, health care, pharmaceutics, food industry, etc. Chemical resistance is assessed by standard international methods defined by ISO standards.

resistance against water

at 98 °C
The test is carried out according to ČSN ISO 719. Data of the extract from 2 g of crushed glass, grain size between 300 and 500 μm, with water of degree of purity 2, for 60 min at 98 °C, are used for practical purposes.

at 121 °C
The test is carried out according to ČSN ISO 720. Data of the extract from 10 g of crushed glass, grain size between 300 and 425 mm, with water of degree of purity 2, for 30 min at 121 °C, are used for practical purposes.

resistant against acids

The glass SIMAX, same as all internationally approved borosilicate glasses, is practically resistant against all aggressive agents except for hydrofluoric, fluorosilicic, phosphoric acids and hot concentrated lyes which markedly attack glass contact surfaces.

Glass surface is attacked by hydrofluoric acid even at low concentrations. Phosphoric acid and lyes attack glass at low temperatures and concentrations only slightly. At high concentrations and temperatures, glass resistance markedly decreases. Permanent alternation of acidic and alkaline environment increases corrosion.

The test is carried out according to ISO 1776. Sample pieces, size 30–40 cm2, are subject to the effect of an aqueous solution of hydrochloric acid at 100 °C for 3 hours.

resistance against alkalis

The test is carried out according to ČSN ISO 695. Sample pieces, size 10–15 cm2, are submerged in boiling solution of same volumes of sodium carbonate and sodium hydroxide for 3 hours.