Increased Filler Content in Graphic PapersEssential Expertise for Water, Energy and Air 6 SM Technology • Basis of Nalco’s approach: Increase particle size of filler in order to

1Essential Expertise for Water, Energy and AirSM

Increased Filler Content in Graphic Papers

K. M. Broadus, M. A. Ancona, W. Cheng, R. T. Gray, D. Castro


Abstract

• Purchased virgin fiber can cost 5 times more than filler.

• Nalco’s technology delivers increased ash content while preserving the sheet’s strength and optical properties.

• Pilot and commercial machine data will be presented.


Conclusions

• Successfully used to increase sheet ash content up to 5 units while maintaining sheet attributes in pilot and commercial machines.

• UCFS mill has utilized this technology consistently for over 1 year across all paper grades.

• Improved internal bond strength is a key deliverable.

• Resulted in equal or less dust in printing and converting trials, even at higher sheet ash levels.


Raw material cost reduction is a key business driver for every papermaker in

today’s market.

The cost of filler (PCC and GCC) is approximately

20% of the cost of purchased virgin fiber.

Raw Material Fiber50%

Specialty Chemicals

2%

Commodity Chemicals

10%

Fixed Costs10%

Water / Energy20%


30

35

40

45

50

55

19 21 23 25 27 29 31

% Filler in sheet

She

et s

tren

gth

(ten

sile

inde

x N

m/g

)

Challenges in higher filler usage

Loss in sheet strength as filler level increases

Dusting and picking in converting and printing operations


Technology

• Basis of Nalco’s approach: Increase particle size of filler in order to minimize the interference with the fiber-fiber bonding strength network

• Controlled size distribution of filler flocs provides strength without compromising the formation and optical properties of the sheet

0

2

4

6

8

10

12

14

1 10 100 1000

particle size, um

Vo

lum

e P

erce

nta

ge,

% untreated PCCprefloc PCC

• Designed for ash increases of 3-5 points

• Applicable for PCC, GCC or a blend of PCC/GCC

• Intended for UFS and CFS grades; demonstrated with a variety of furnish types

• Treated on-site; no holding time required before use

• Introduced with minimal adjustments to paper machine operations


Differentiation

• Differentiation is achieved through a combined chemical and mechanical approach.

• Offering is strengthen by Nalco’s expertise in wet-end operations and papermaking.

Controllable MethodWell-defined particle size distribution of filler flocs

PCR™TechnologyPARETOTM

PCR™TechnologyFillerTEKTM

Improved StabilityFiller flocs exhibit improved shear stability ROI

Maximize your profits by raising the limits


Impact of Bond StrengthPilot machine trial on EuroFEX gap former, 1000 m/min

• The ash level can be increased by 10 points without a loss in internal bond strength as measured by z-directional tensile.

• Eucalyptus /pine furnish, 80 gsm sheet produced in pilot trial at Innventia AB


Impact of on OpacityPilot machine trial on EuroFEX gap former, 1000 m/min

• Opacity loss due to filler treatment can be recovered with a 2.5 point increase in ash content.

• Eucalyptus /pine furnish, 80 gsm sheet produced in pilot trial Innventia AB


Impact of on FormationPilot machine trial on EuroFEX gap former, 1000 m/min

• Sheets showed a slight improvement in Kajaani formation relative to untreated PCC, at comparable FPR and FPAR values.

• Eucalyptus /pine furnish, 80 gsm sheet produced in pilot trial Innventia AB


Commercial Application

• Uncoated free sheet mill in Latin America:– Produces 75 gsm copy paper and offset grades

– Top-former machine operating at 800 m/min; 400 TPD

– Using a blend of PCC/GCC

• Sheet ash:

– Historical ash level was 18%; currently at 23%

• Utilized continuously across all grades for over one year.– Paper machine runnability is good:

• Production rate stable

• Sizing (ASA) usage steady, despite filler increase


Impact of Sheet PropertiesCommercial Account

Results represent an average of 10 samples randomly selected from 10,000 sheets.

Mill incorporated BCTMP in furnish for cost savings and bulk advantage.


Distribution of Filler in Z-DirectionCommercial Sheets

• z-Direction ash profile remains similar at the higher level.

Sheets were found to generate 47% less dust in a converting study of 10,000 sheets.

0

5

10

15

20

25

30

0 10 20 30 40 50 60 70 80 90 100

Relative Basis Weight, %

Ash

, %

Untreated PCC/GCC blendTreated PCC/GCC blend


Print Trial at RIT

• Goss Sunday heat set offset press; 4 head (KCMY), 28,000 impressions

• Commercially produced 75 gsm text grade sheets:

– Untreated PCC at 25% ash

– Treated PCC at 25% and 29% sheet ash

• No runnability problems observed at higher sheet ash.

• Linting was monitored by tape pulls of printing blanket.

SEM images of tape pulls

Top side Bottom side


Reduced Linting in Print Trial

75 gsm text grade

25% Filler 25% Prefloc 29% Prefloc

B C M Y

0

5

10

15

20

25% Filler 25% Prefloc 29% Prefloc

Ca

coun

ts• Tape pulls of printing blanket were analyzed for calcium

(Ca) levels by EDS (energy dispersive x-ray spectroscopy).

• Conclusion: Linting decreases with Chemical technology.

Top Side Bottom Side

Increased Filler Content in Graphic PapersEssential Expertise for Water, Energy and Air 6 SM Technology • Basis of Nalco’s approach: Increase particle size of filler in order to

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