Papertechnology paper properties

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Paper technology

Paper properties

Technical Support Sappi Fine paper Europe


Colour space


Measuring methods

Colour space Lambda-Spectral area


Measuring methods

Gloss Roughness

Brightness


Conversion

Rate of factor THICKNESS BULK :

Rate of factor BULK THICKNESS :

Thickness (mm)

BULK (cm3/g) = x 1000

Basiswight (gsm)

Bulk (cm³/g) x Basiswight (gsm)

THICKNESS (mm) =

100


Formulas

Length (cm) Weight of the pallet (kg) 0,0

Width (cm) Height of the pallet (cm) 0,0

Number of sheets Number of sheets #DIV/0!

Dicke (µm) Bulk #DIV/0!

Grammage (g/m²)

Weight of the pallet (kg)

Start of the Excel-file with double-klick !

For your input please use the grey fields only !

When you will have the number of sheets no data in the grey field !


Machine direction

Machine direction 1000 x 700 mm

700 x 1000 mm

Wid

e w

eb

Small web


Machine direction

1. The nail test.

Pressure with the

finger nail over both

edges creating a

differently strong

corrugation formation.

3. The humidity test

A piece of paper is taken

off the sample sheet and

moistened on one side.

The rolling-in, caused by

the humidity expansion,

indicates the machine

direction.

2. The strip test.

Two strips with the

same length and width

are cut out off the length

and width of the sheet. If

these strips are hold

horizontally, the

deflection of the strip is

stronger in crosswise

direction.

4. The tearing test.

By tearing down the

sheet in longitudinal

and crosswise

direction the machine

direction can be

learned from the

tearing edges.


Machine direction

1. The more wavy side is located

crosswise to the machine direction.

2. The more rigid strip is lying in machine direction

3. The sides with the edges coming to the

top are in machine direction.

4. The smoother tear is parallel to the

machine direction.


Humidity of paper

Relative Humidity = Air humidity between sheets and between paper windings of a reel

Absolute humidity = % humidity in the paper


Temperature °C Relative air humidity (RLF) in %

10 64 73 82 94

12 55 65 73 82 92 98

14 49 59 65 73 82 87 97

16 43 55 57 65 78 87 93 97

18 38 45 50 57 64 70 75 83 85 95

20 34 40 45 50 56 62 67 73 76 84

22 30 35 40 45 50 55 60 65 70 75

24 27 32 35 40 45 50 54 67 62 68

26 25 28 32 37 40 45 47 53 55 60

28 22 26 28 32 36 42 43 46 50 55

30 20 23 26 29 33 38 39 43 45 50


Recommended time for the acclimatisation of

pallets in hours

Paper quantity per pallet Temperature difference of the paper Storage room

5 °C 7 °C 10 °C 15 °C 20 °C 25 °C 30 °C 35 °C

approx. 0.2 m3 4 7 9 15 21 28 41 62

approx. 0.4 m3 7 12 17 26 36 41 64 92

approx. 0.6 m3 9 15 20 31 42 55 76 107

approx. 1 m3 12 18 23 33 46 63 84 115

approx. 2 m3 13 19 24 35 49 66 90 123


Flat position

Baggy

middling

Wavy-edging


Classification of papers coated on both sides for the sheet

and web offset printing

• Originally coated art papers

Coated papers of highest quality for a high demand. Very high coating of

very high uniformity and elegance. Best printability and processability.

• Specially coated picture printing papers

Coated papers for demanding and high quality printing jobs with a high

quality constancy and reliability. Very economic printability and

processability.

• Standard picture printing papers

Coated papers for the daily need for which standard quality is sufficient.

Numerous manufacturers of such papers produce different qualities.

• Consumer picture printing papers

Coated papers for simple printing jobs for which not the highest quality

regarding gloss and uniformity of the printing picture is required.

The coating is carried out within a paper machine or offline, this means separately on a

coating machine. The coating quantity mounts to 5 – 30 g/m² per side depending on the

quality. With a decreasing coating quantity, also the gloss may decrease as well as the

uniformity of the coat (cloudy formation) and the smoothness.




• LLWC/ULWC papers

Light Light Weight Coated Paper

Ultra Low Weight Coated Paper

Ultra-light Coated Paper

Wood-containing, with secondary fibres produced paper.

Basis weight 35-51 g/m² - coating weight : 5-10 g/m²

Especially for web offset printing.

• LWC papers

Light Weight Coated Paper

Light Weight Coated Paper for runs in the web offset printing

Coated paper especially for the Heatset web offset printing.

Basis weight: 51-73 g/m² - coating weight: 10-20 g/m²

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• MWC/HWC papers

Medium Weight Coated Paper

Heavy Weight Coated Paper

Wood-Containing Coated Paper

Coated papers in the basis mass of 70-170 g/m².

Coating weight: 15-20 g/m² per side. They are also called picture printing or

specially coated papers.

• Cast-coated papers

Wood-free papers of high quality for labels, packing, envelops and folders.

Very high gloss, mostly cast-coated on one side.

Basis weight: 70-400 g/m² - coating weight: above 25 g/m².

White, coloured and with a metallic surface.

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Uncoated papers (natural papers) for the web offset

printing

• WSOP paper (Web Special Offset Paper)

Wood-containing paper, calendered uncoated paper for web offset printing.

• SC paper (= Super Calender)

Wood-containing, uncoated paper with high smoothness by glazing.

Especially for the web offset printing.

• B pulp paper

Uncoated, glazed paper for web offset printing. Compound of the pulp: wood

pulp, ground wood pulp and fillers. The brightness is determined.

• Newspaper printing paper

Uncoated paper mainly produced from secondary fibres (used paper). Here,

difference is made between “standard” and “improved”. Basis weight: 39 to

50 g/m². The smoothness, the absorbency, the colouring and the opacity are

especially of importance for the printability.

• Continuous papers

Wood-free to slightly wood-containing and also with more or less secondary

fibres. For text and data processing. The properties are determined in DIN

6721.

• SC-HSWO papers (Super Calendered Heavy Special Web Offset Papier)

= calendered, uncoated paper with high basis mass (basis weight).


Technical Support

Sappi Fine Paper Europe

In case of questions or remarks

contact Oliver Kropacek

Education

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