A New Mechanism for Enhancing Adhesion of ...RESULTS: 3-Star Qualification • No runnability issues • Muted response to ID-115 –unable to reach high 90s of adhesion • No loss

Dr. Daniel F. VarnellResearch FellowSolenis LLC

A New Mechanism for Enhancing Adhesion of Electroreprographic Printing with Liquid Toner

2 Confidential and proprietary.

Overview Liquid Toner Digital Printing

• Digital printer (every page unique)

• Electroreprographic with offset blanket

• Liquid toner

Pigments in anionic P(Et/AA)

Suspended in volatile oil

• Up to seven colors and use of custom

colors

• Offset print quality

Conforms to surface

High resolution

• Growing digital market Digital Press


Objective

• An easy-to-use additive that imparts 3-star performance (by HP standards) at a cost at least 25% lower than current systems


Toner Adhesion Measurement (HP Method)

• Tape test under controlled conditions

• Best rating is 3-stars Adhesion >90% for black, >80% for 290% photo black

• 290% Photo Black (52% y, 66% m, 72% c, 100% k)

• Image scanned and analyzed

• Rochester Institute of Technology (RIT)


History of Indigo Paper Additives

Polyethyleneimine

• Expensive

• Time-consuming

• Yellowing

Poly(ethylene/acrylic acid) dispersion

• Inefficient

• Compatibility issues

• Difficult to run

• Trouble with broke

Anionic polystyrene

• Less addition (< 6#/ton)

• Easy-to-use

• 2-star, or weak 3-star performance

How the Additives Work and Introduction of a New Concept and Product


Thermodynamics of Adhesion Between Polymers

• Materials will mix or adhere if free energy decreases

D Gmix = Gf - G0 =(Hf - TSf) - (H0 - TS0) = (Hf - H0) - T(Sf - S0)

D Gmix = DHmix - T DSmix

Entropy of Mixing

• Favorable

• Mixing is more

random

Heat of Mixing

• Unfavorable

• Unless interaction

= (Hf - H0 ) - XAB


• Polyethyleneimine

Water soluble

Ionic interactions

Heat of mixing becomes favorable

XAB = dAB – ½(dAA + dBB)

_ _

Ink with anionic change

PEI has cationic charge

+

+

+

+

dAB becomes larger

XAB becomes larger (favorable)

Mechanisms of Adhesion


• Poly(ethylene/acrylic acid)

Dispersion

Same chemistry as in ink

Melts together

Heat of mixing unfavorablebut is very small

“Like-dissolves-like”

P(EtAA)

P(EtAA) P(EtAA)

P(EtAA)P(EtAA)

P(EtAA)

XAB = 0 and DHmix = 0



• New Concept

Water soluble

No ionic interactions


XAB = dAB – ½ (dAA + dBB)

• By decreasing self interaction

dAA made smaller


BB BB

A

AA



• New Concept

Water soluble

No ionic interactions


XAB = dAB – ½ (dAA + dBB)

• By decreasing self interaction

dAA made smaller


B

B B B

A

AA



• New Concept

Decreasing self interaction

Potential for strong dipole interaction

Favorable to mixing/adhesion


Print


Initial Experiment

73

68

82

67

99

80

55 56

62

53

99

61

40

50

60

70

80

90

100

blank starch anionic PS P(Eth:AA) EXP #1 EXP #2

Ima

ge

Ad

he

sio

n (%

)

100% Black 290% Photo Black Exceptional

Dixon Coater on Fine Paper

4% Ethylated Starch, 0.2% Additives

Testing by RIT

Wonder is the

beginning of wisdom. — Socrates

Let the sea resound, and all that is in it.


Concept Confirmed

60

70

80

90

100

Ima

ge

Ad

he

sio

n (%

)

100% Black 290% Photo Black


Product Optimization

85

90

95

100

0 0.1 0.2 0.3 0.4

% A

dh

esio

n% Formulation to Paper

Photo Print Adhesion

Original

Optmized

• Optimized

• Performance varies by base sheet

• Enhancements ongoing


Case History #1

GOAL: Make HP Indigo Grade

• Wet-End: precipitated calcium carbonate (PCC) and some sizing

• Size Press: cationic starch, optical brightening agent (OBA), sodium chloride (NaCl)

0.4% New Product

RESULTS: 3-Star Qualification

• Qualified on first run

• No wet-end changes

• No size press changes

• No issues with runnability

• No changes of other properties

70

80

90

100

100% Black 290% PhotoBlack

Image A

dhe

sio

n (%

)

Qualification Testing

Also easily passed blanket

compatibility test


Commercial Case Study Details – Mill A

Grades from 55 pound to 100 pound have been qualified

• 6 dry pounds per ton of DPZ-667

• Optimization trials will continue

• Strong 3-star (99 plus adhesion), no blanket compatibility issues

• ~ 16% filler content with PCC

• 55 pound grade has typical properties of 115 Sheffield Smoothness and 22 Gurley Porosity


Performance - Mill Results

• Wet-end PCC

• Size press: Cationic Starch; OBA, Salt; 0.3% DPZ-667

CONDITIONS:

• 100% Black Print - 100% Repeat - 99% adhesion

• 290% Photo Print – 100% Repeat - 99% adhesion

ADHESION:

• Perfect! No change in size press viscosity or pick-up

RUNNABILITY:

• Unchanged

PAPER PROPERTIES:

• Test easily passed

INDIGO BLANKET COMPATIBILITY:

• Qualified

3-STAR QUALIFIED:

• Trial paper sold as offset with no issues.

ISSUES:


Bottom Line: A Versatile Solution

• Wet-end

Low and high levels of PCC

AKD and ASA sizing

Wide range of sizing level

Virgin and recycle fiber

Wide range of basis weights

• Size Press

Anionic, Ethylated, Cationic Starches

Puddle and Metered Size presses

All size press additive are compatible

Sheet Porosity Important


Performance - Additives

• OBA

• Salts

• Some defoamer

• Some proprietary additives

Things that can be added with no impact:

Learning more all the time

Compatibility test should be conducted for each size press formulation (ask Solenis about this)


Case History #2 (challenging base sheet)

GOAL: Make HP Indigo Grade

• Wet-end: PCC & low level ASA Sizing, 115g/m2 , Gurley Porosity of just 13

• Size-Press: Ethylated starch, OBA, NaCl

• Goal: High level of photo adhesion

RESULTS: 3-Star Qualification

• No runnability issues

• Muted response to ID-115 – unable to reach high 90s of adhesion

• No loss of any other properties

• Qualified on first run

• Sheet sold for offset printing

70

80

90

100

w/o ID-115 w 0.3% ID115

Image A

dhe

sio

n (%

)

RIT testing Photo Images

OPTIONS

1. Switch to cationic starch

2. Addition of rheology modifier

3. Solenis proprietary additive


Variations for Difficult Base Sheet

80

85

90

95

100

Ethylated Cationic

% A

dhesio

n

100% Black 290% Photo Black

Effect of Changing Size Press Starch

One could also add a rheology modifier


Advantages for Papermakers

CHARACTERISTIC P(Et/AA) New Product

Water Soluble No Yes

Starch Compatibility Limited All

Efficiency Poor Excellent

OBA Compatibility Limited All

Solids 25-30 15-35

Recycle Broke May cause issues Unlikely to cause issues

Runnability Deposits, Incompatibility No adverse effects

Cost Too Much 25% less for materials

more savings by quicker

grade changes


Performance – Pilot Results

Conditions: Light weight commercial base sheet w/o surface size; Dixon coater; 80#/ton

ethylated starch

With this base sheet most of performance obtained with just 3#/ton DPZ-667

50

55

60

65

70

75

80

85

90

95

100

0 2 4 6 8 10 12

% A

dh

esio

n

#/ton active DPZ-667

INDIGO INK ADHESION – RIT TESTING (New Tape)

100% black

290% Photo


Performance: Optimum Conditions

• Keep product at the paper surface

More closed sheets are better

Normal or higher starch viscosity

Cationic starch versus non-ionic or anionic starches

Metered size press equipment

• Better if size press temperature is below 55oC

• Rheology modifiers: Topcat98 starch, HEHEC, Ecosphere,


Specialization

• For many mills the standard product works great!

• Not every mill has the same goals

• Some base sheets can present unique issues

• Some paper machines have unusual limitations

• Solenis is willing to work with each mill to be successful


INTELLECTUAL PROPERTY

Three patent applications


AVAILABILITY

Commercial in any quantity in USA

Limited quantities in Europe until REACH listed (2018), available for trials and small production scale

Lead time for orders:

USA: 2-3 weeks / Europe: Yet to be established


REGULATORY INFORMATION

FDA - In the future, no issues expected

REACH COMPLIANCE – In progress, trials can be run in Europe


OTHER PROPERTIES

Enhances dry toner adhesion

Ink-jet additive compatible (as tested to-date)

No effect on offset printing


GOAL

• An easy to use additive that imparts 3-star performance by HP standards at a cost at least 25% lower than current systems.

* 100% adhesion has been achieved even with 290% photoprinting

Documents

A New Mechanism for Enhancing Adhesion of ...RESULTS: 3-Star Qualification • No runnability issues • Muted response to ID-115 –unable to reach high 90s of adhesion • No loss