The boards are characterised by high density, high purity, uniform thickness, dimensional stability, low compressibility, and low shrinkage and high electrical strength.

WIPRESS - Precompressed Pressboard
Reference Standard	IEC 60641 – Part 3, Grade B.3.1
General
Appearance	Hard rigid sheet light brown in colour with wire marks on both sides
Raw Material	100% Sulphate Pulp
Nominal Size	2.20 X 1.10 m
Thickness	0.5 to 6.0 mm
Thickness tolerance % max	mm     1.6 ± 7.5   >1.6 ± 5.0
Physical Properties
Density, g/cc range	mm     1.6 1.00 - 1.20   > 1.6 - 3.0 1.10 - 1.25   > 3.0 - 6.0 1.15 - 1.30
Moisture content, %, max	6
Ash content, %, max	1.0
Shrinkage, %, max	MD CMD Thickness 0.5 0.7 5.0
Oil absorption, %, mm	mm     1.6 11.0   > 1.6 - 3.0 9.0   > 3.0 - 6.0 7.0
Cohesion between plies	PPass – split would show rupture of one or more plies and would have distinctly ragged appearance.
pH of. Aqueous extract, range	6.0 - 9.0
Mechanical
Tensile Strength, Mpa	mm  MD  CMD 1.6 100  75 > 1.6 - 3.0 105  80 > 3.0 - 6.0 110  85
Elongation, %, min	mm  MD  CMD 1.6 - 6.0 3.0 4.0
Compressibility C, %, max	mm     1.6 10   > 1.6 - 3.0 7.5   > 3.0 - 6.0 5.0
Reversible part of Compressibility Crev, %, min	mm     1.6 45   > 1.6 - 6.0 50
Electrical
Conductivity of aqueous extra, mS/m, max	mm     1.6 5.0   > 1.6 - 3.0 6.0   > 3.0 - 6.0 8.0
Electric strength kV/mm, min	mm In Air In Oil 1.6 12 40 > 1.6 - 3.0 11 35 > 3.0 - 6.0 10 30

MD – Machined Direction, CMD – Cross Machined Direction
Conditioning and testing procedure as per IEC 60641 – Part-2.
We also make Pressboards (Transformerboard) confirming to DIN 7733 – Type PSP 3052