This
cotton ("rag") grade has proved to be one of the most
successful electrical presspapers and has been in continuous production
for well over 60 years.
ELEPHANTIDE®
Grade 4 Presspaper exhibits a unique combination of superior electrical
strength, mechanical toughness and flexibility and has proved
durability under the most arduous service conditions. The furnish
is made up of 100% new cotton threads which are mechanically and
hydraulically processed before forming on a multi-cylinder machine.
Continuous improvements have been made by taking advantage of
better raw material sources and modern developments in processing
techniques.
Technical
Data
Standards
Achieved
BS EN 60641
P.4.2 Pressboards and Presspapers for
Electrical
Purposes
Furnish
Cotton 100%
Colour
Blue
Thickness
Tolerance
+/- 10%
Parameter
Unit
Typical
Values
Apparent
Density
g/cm^3
1.05
to 1.20
Tensile
Strength
MD
N/mm^2
75
to 90
CMD
N/mm^2
32
to 43
Electric
Strength
KV/mm
In
Air
In
Oil
0.127
mm
14.0
74
to 88
0.18
mm
14.5
70
to 88
0.25
mm
13.5
68
to 77
0.30
mm
12.0
60
to 74
0.40
mm
10.5
52
to 63
0.50
mm
10.5
50
to 53
Conductivity
mS/m
2.5
to 5.0
pH
of Aqueous Extract
7.5
to 8.0
Ash
Content
%
0.2
to 0.35
These
figures are typical values only and as such do not constitute
a specification.
