AdphosNIR ® Innovations in Thermal Processing Optimized Drying and Curing Processes for New Functional Products Dr. Kai K. O. Bär adphos Digital Printing.

adphosNIR® Innovations in Thermal Processing

Optimized Drying and Curing Processes for New Functional Products

Dr. Kai K. O. Bäradphos Digital Printing GmbH

NIR is a trademark of adphos. adphos owns more than 200 patents- or patent applications on the NIR-technology

InPrint Show, November 10th, 2015 – Munich/Germany


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Functional Coatings

Thin Layer Film Applications 1 µm to 0.1 mm one/more Wet/dry or

gaseous or organic ornon-organic coatings

InkJet Roll coating

(flexo, gravure, offset) Screen Curtain Powder coat PVD, CVD …

and Treatment On Substratesin combination with Drying

Heating (melting, sintering, deposition)

Curing (heat/radiation)

only on surfaces Flat/cured/3D Continuous/sheet/batch


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Dry –What is it?


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What is Dry at

Drinks?

100 % UV-based coatings?

H2O/solvent based UV coating?

Thermal curable power?


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Dry(ness) is not a proper quantified physical parameter!

Quelle: www.ClipProject.info


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Drying and Curing (Heating) Processes (1)

Starts with Wetting and spreading at the surface

porous non-porous

Dehydration• Suction into substrate• Unforced drying by ambient evaporation over time• Removal of moisture/viscosity increase


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Drying and Curing (Heating) Processes (2)

Fixing coating to substrate• Mechanical adhesion• Bonding• Over coating

Final coating treatment for functional properties• Curing• Sintering


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Typical Todays Drying Technologies

• Hot air driers

• Hot drum/hot plate + hot air

• (m)IR and hot air

• (adphos)NIR®-dryer (with integrated high airflow rate, warm impingement air, air ventilation and removal)


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Working Principles (1)

Hot Air – heat transfer by heat convection

• Complete surface is heated relying on conduction through the ink/substrate

• Dries non-printed areas before all of ink pattern has been dried

• Circulating air can help remove the water molecules from the surface

• Air is generally heated outside of the drying system

• Very slow drying processSubstrate

Hot airDrying

heating by conduction


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Required Power for Hot Air Dryers

Drying Power: ≙ Energy to heat up substrate mass +

Energy to evaporate water

(from ink pattern and removal of ambient

moisture in the paper)


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Hot plate/heated drum – heat transfer by hot contact area (conduction)

• From backside up approach• Heats the substrate before the ink film• Relies on conduction• Drives water up to the surface• High amounts of residual heat


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Required Power for Heated Drum




moisture of paper)


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IR (Infra Red – Short, Medium To Long Wave) – only heat transfer to the surface by radiation

• Top down approach• Heat absorption at complete

substrate surface • Dries non-printed surface before

ink patterns are properly dried• Relatively slow drying process


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Midwave IR Heats Both the Substrate and Printed Pattern – Nearly Equal Absorption

mIR is “color blind”for printed pattern


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Required Power of IR-Dryer




moisture of paper)


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NIR (adphosNIR) – heat transfer/process by Near Infra Read radiation

• High energy density penetrates ink film drying from the bottom up

• High energy density excites water molecules instantaneously

• Paper substrates are highly transparent to NIR producing limited substrate heating

• Emitters can be controlled across the web drying only areas being printed

• NIR has a high energy density (ultra fast drying process)


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NIR-Drying Shows High Absorptionin the Printed Pattern


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Required Power for adphosNIR®-Dryer

Drying Power: ≙ Majority Energy to remove (evaporate) the water from the ink pattern

Remark:

Substrate temperature rise results from heat conducted from the

ink pattern and by minor direct absorption of NIR.


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adphosNIR® allows

- Instantaneous setting of coatingstops spreading and penetration

- Instantaneous evaporation of water and solventswater removal and disruption of high boiling temperature humectants (e.g. Glycol)

- Low thermal stress on the non-printed substrateno dry out no remoistening needsapplicable for thermal sensitive substrates (e.g. thermal paper, plastics, …)no afterwards web cooling required

High dryer efficiency, enhanced print quality (higher color density, higher crisp) and improved speed range


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Application Example (1)Enhanced Drying in Digital Printing Press

Speed: 120 m/min for all applicable substrates- Uncoated- Coated esp. regular offset

Speed: Up to 120 m/min only uncoated substratesUp to 80 m/min limited to some coated substrates only

Energy consumption:

Depending on paper width, ink coverage,paper type40 kW to max. total 70 kW80 – 100 kW

Flat products no remoistening

Wavy, strong dry out (needed 5 g/m² remoistening)

Drying length: Total 300 mm

Total 1,200 mm


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Application Example (2)Process Color Printing on Corrugated Boards

Speed: 200 m/min

Width: 1,300 mm

Total drying length:

1,500 mm

• Alternative driers get “banana shape” boards

• Low temperature (60 °C) air driers would require > 10 m

• Requires extreme more drying energy (2.5 – 3 times!) compared to NIR

A = Pre-Treatment DriersB = InkJet Driers


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Application Example (3)Process Color Printing on Plastics

Speed: 50 m/min

Width: 2,500 mm

Substrate: PP, vinyl and other plastics

Interstation dryer configuration

Þ Only final dryer configuration results in intercolor bleeding

Here for no alternative driers with thermal inks are applicable


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Application Example (4)

Ink Jet Printing of nano silver inks on PET/Paper

• Hot air oven: 10 min @ 70 °C +20 min @ 150 °C

• Midwave IR: 1 min @ up to 150 °C

• adphosNIR®: 1-4 s @ up to 250 °C (coating) and< 120 °C at substrates

• Xe-Flash: 2 - 15 s depending on coating thickness


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Application Example (5)Additive Manufacturing – 3D Printing

Speed: Up to 30 – (60) m/min

Width: Up to 2,000 mm

Materials: Plastics, metals!

Special unique benefits with adphosNIR®-processing

• Preheating of plastics only up to crystallization point

• Metals can be processed from ambient • Instantaneous melting of

“printed/coated” area• Width adjustable heating power• Powder reusable due to low thermal

treatments

Quelle: http://www.lboro.ac.uk

http://www.lboro.ac.uk/departments/mechman/research/manufacturing/additive-manufacturing/

http://www.lboro.ac.uk/departments/mechman/research/manufacturing/additive-manufacturing/


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Conclusions

• Drying starts immediately with the coating drop down• Drying technology and configuration can strongly effect

– coating process performance and– coating process quality and– coating process applicability (is do-able or not!) and– energy consumption and– mandatorily drives the costs of coated product• coating process costs• substrate costs (due to required type of substrate)• coating costs (consumption)• Coating process preparation and standby• total energy costs (startup, standby and print production, eventual cooling, remoistening, …)

• adphosNIR® allows application optimized systems design and is already widely proven in coating processing


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Even though none of the today´s post processing technologies does fit for all –

adphosNIR® shows large benefits and wide range applicability

See us at our booth A6/G42 or at www.adphos.de

http://www.adphos.de/

AdphosNIR ® Innovations in Thermal Processing Optimized Drying and Curing Processes for New Functional Products Dr. Kai K. O. Bär adphos Digital Printing.

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