Hardened highly pure filter papers (ash content approx. 0.05%) with extremely high chemical and mechanical resistance, especially recommended for vacuum and pressure filtration, and for the use of acidic and alkaline solutions.

• Made of super-refined cotton linters and cellulose
• alpha-cellulose content above 95%, therefore high stability and durability
• High wet strength; easy to scrap off or wash off precipitates, no fibre release
• Hardened by small quantities of nitrogen-containing resin, which does not introduce significant impurities into the filtrate
• Very low content of minerals (approx. 0.05% ash)

• High resistance to aggressive chemical components, like sulphuric and nitric acids (up to 40% at 50° Celsius) and alkalis (up to 10% at 20° Celsius) and alkalis (up to 10% at 20° Celsius).

These filters are available as filter circles with the following sizes as standard (in mm):

6 - 12,5 – 12,7 – 40,5 – 47 – 55 – 70 – 90 – 110 – 125 – 150 – 185 – 240 – 320.

Other sizes, sheets, rolls and special cuts are available on request.