dwr dynamic water retention presentation

DWR by1

DWRPortable Dynamic

Water Retention unit

DWR by

Main Advantages

Dynamic like coating processes.

Best correlation to the real coating processes.

Real results with coating colors including starches.

No pigment cake problems.

Can analyse qualities of base papers and base boards.

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DWR by

Customers

Stora Enso

Nippon Paper

Iggesund

Basf

CP Kelco

KCL

MetsäBoard

Imerys etc.

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DWR by

Portable Dynamic Water Retention Unit

Possibility to measure characteristics of coating colors as well as influence of different base papers on the water retention.

Traditional static analyzers always have a risk for pigment cake formation or starch retrogradation, which prevent the flow of coating color to the base paper. There are pressure and shear forces in DWR during the measurement without any blocking risk.

Due to the dynamic flow DWR has an excellent correlation to real coating processes.

Measurement cycle with weighing is about three minutes.

DWR has automated cleaning cycle.

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DWR by

Operation on DWR

Adjustable measuring time.

Measuring pressure one (1) bar.

Coating color flows under base paper during measurement.

Measurement is dynamic for simulations of different coating methods (blade, film, curtain, spray etc. coating methods).

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DWR by

Measurement results with DWR

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Sample

Color A

Color B

Base paper I

Baser paper II

Dynamic water retention [g/m2]

Measurement time 6 s

26,1

22,8

26,1

32,5

Base paper measurements done using color A

DWR by

Measurement Results

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Paper 1 WR [g/m2] Time [s] Pressure [bar]

1 16,0 3 1

2 18,5 3 1

3 18,5 3 1

Paper 2 WR [g/m2] Time [s] Pressure [bar]

1 39,5 3 1

2 39,4 3 1

3 42,0 3 1

Base Papers 1 & 2 with Coating Color 6

Average 17,7 g/m2

Average 40,3 g/m2

WR =

Dynamic

Water

Retention

DWR by

Porosity and Coating Coverage

Dense sheet – small penetration of coating color and good coating coverage and gloss.

Porous sheet – deep penetration of coating color and poor coating coverage and gloss. Misting problems in film coating.

8Forsström et al. TAPPI Coating Conference, 2002

http://www.kcl.fi/news/link12004/link12004s4.html

DWR by

Portable Dynamic Water Retention unit

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Sample chamber

for coating color

Measuring

position

DWR by

Measurement Procedure

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DWR by


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Coating color

DWR by


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Membrane

filter

DWR by


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Base paper

DWR by


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Cover

dwr dynamic water retention presentation

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