Laboratory Product Catalogue Total Laboratory Science Support

Filter Papers
Introduction
Generally filter papers are used for separating
substances of different physical states.
They are absorbent, porous fiber materials.
The fibrous structure of filter papers forms
a capillary system. The intercapillary spaces
depend, according to their size and number,
on the raw materials used and may be
influenced by the beating in the hollander
and the way the paper machine works.
We use natural and synthetic, organic and
non-organic fibers. In order to obtain special
properties, they are partly treated chemically
and are impregnated with synthetic resins.
Sartorius filter papers are made to a great
extent from pulps of pine or spruce wood, but
also of birch, beech and eucalyptus wood,
cotton linters and viscose pulp.
These raw materials are refined to different
filter papers with graded properties by wet
beating in hollanders and sheet formation on
specially modified paper machines.
Ashless filter papers
These filter papers are used for quantitative
analysis. They are made of refined pulp and
linters with over 95% alpha-cellulose content.
Moreover, these filter papers are guaranteed
to be free of any residual acids that are
used in a few production methods. Another
advantage is their extremely low percentage
of ash content. As a result, these filters are
virtually ash-free.
Sartorius Ashless Filter Papers, with the grade
Numbers 388, 389, 389F, 390, 391, 392 and
393, are characterized by high wet strength
and high purity, classified according to their
separating capacity.
Qualitative filter papers
Like our ashless filter papers, these filter
papers are made of refined pulp and linters
with an alpha-cellulose content of more
than 95%. This gives them a variety of filter
properties to meet the needs of different
applications. The ash content of these filter
papers is approx.