Definition of borosilicate glass

The international standard ISO 4802. 1-1988 "Water resistance of the inner surface of glassware and glass containers Part 1: Determination and classification by titration" defines borosilicate glass (including neutral glass) as containing diboron trioxide (B -2O-3) 5～13% (m/m) of glass, but the ISO 12775 "Classification of Glass Composition and Test Methods for Normal Mass Production" issued in 1997 defines borosilicate glass (including neutral glass). Boron trioxide (B-2O-3) is greater than 8% (m/m). According to the principle of glass classification in 1997 international standards, the B-2O-3 6 %(m/m) glass material widely used in my country's pharmaceutical glass bottle industry for many years should not be called borosilicate glass or neutral glass. Tests have proved that some of the glass particle water resistance and inner surface water resistance tests of this type of material are not up to Class 1 and HC1, or are at the edge of Class 1 and 2. Practice has also proved that some of this type of glass will have neutral failure or peeling during use, but this type of glass has been produced and used in my country for many years. The new standard retains this material of glass and stipulates its B-2O- The content of 3 should meet the requirement of 5-8% (m/m), which clearly defines that this type of glass cannot be called borosilicate glass (or neutral glass), and it is named low borosilicate glass.

Glass material type: There are 4 types of glass in the new standard, including 2 types of borosilicate glass, including 3.3 borosilicate glass [α=(3. 3 ±0. 1) ×10 (-6) K(-1) ] And 5.0 neutral glass [α= (4～5) ×10 (-6) K(-1) ], low borosilicate glass [α= (6.2～7.5) ×10 (-6 ) K(-1) ]1 kind, soda lime glass [α= (7.6～9.0) ×10 (-6) K(-1) ]l kinds, so there are 4 glass types according to the material