High Filler Content PaperHigh Filler Content Paperand Board Productsand Board Products

TIP3 2004TIP3 2004--2005 2005 MidMid--Year ReportYear Report

A. Ragauskas, Y. Deng, Z. A. Ragauskas, Y. Deng, Z. YanYan, D. White, D. WhiteInstitute of Paper Science and TechnologyInstitute of Paper Science and Technology

Objectives and Key QuestionsObjectives and Key Questions

•• Develop new bonding fillers to improve existing sheet Develop new bonding fillers to improve existing sheet properties while decreasing fiber costs properties while decreasing fiber costs –– Projected filler loading targets: 100% increase in current Projected filler loading targets: 100% increase in current

filler loadingfiller loading--levels (35% for copy paper, 15% for levels (35% for copy paper, 15% for newsprint, 15% tissue and 15% for container board) newsprint, 15% tissue and 15% for container board)

•• Leverage GeorgiaLeverage Georgia’’s unique manufacturing capabilities in kaolin s unique manufacturing capabilities in kaolin and SW kraft pulp to develop a unique economic advantage for and SW kraft pulp to develop a unique economic advantage for these two industries these two industries –– 5050--100% increase in the use of GA kaolin fillers in GA 100% increase in the use of GA kaolin fillers in GA

paper industrypaper industry•• Key Questions: Modified filler detailed approach and cost, Key Questions: Modified filler detailed approach and cost,

pilot trial on filler modification (feasibility, pilot trial on filler modification (feasibility, runnabilityrunnability, sheet , sheet properties), paper mill trialproperties), paper mill trial

Prior Results• Starch coated and dried on clay

surface can increase paper strength significantly (10-15%) vs. use of unmodified clay– Ring crush

• Different starches (corn, poato, cationic starch) gave similar effects

• Starch amount as little as 2.5% of the filler to give significant positive effect

• Potential to use low cost clay and low grade starch to produce high strength paper/board with high filler content

Ring crush vs. filler content

50

55

60

65

70

75

80

85

0 10 20 30

Filler content,%Ri

ng c

rush

,lbf

pure clay

corn starch modif iedclaypotato starch modifiedclaypotato starch+clay

Milestones, 7Milestones, 7--12/0412/04

• Confirmed benefits of modified clay• Identified and conducted approach to

produce modified clay (pilot spray drying)• Scheduled to measure properties of sheets

containing spray dried modified filler• Planning scaled up spray drying and pilot

trial

Key FindingsKey Findings• Confirmed that clay with coated starch increased the paper

strength significantly, vs. unmodified clay– Ring crush improved significantly with modified filler

at high filler content compared with uncoated fillers• Optical properties (paper brightness, smoothness) of

calendered handsheets improved with modified clay vs. no clay

• Different starches (corn, potato) continue to give similar effects

• Possible to use spray drying to produce the modified clay – Other methods, such as apron drying, are additional

possibilities

Modified Clay Initial Modified Clay Initial Preparation ProcedurePreparation Procedure

• Clay slurry mixed with required amount of starch (e.g., 2.5% based on clay)

• Clay slurry – starch mixture cooked at 50% solids, 95 oC for 30 minutes

• Dried at 50 oC under vacuum• Dried mixture ground for 2 minutes

32126.2

53238.25

14106919.5

31241622351

52463343562

84827088885

969791959810

Percentage less than given particle sizeParticle size (micron)

8.38.27.07.910.7Surface area (m2/g)

7.5%Potato

2.5%Potato

5%Corn

2.5%Corn

Clay

Clay CharacterizationClay CharacterizationClay surface area and particle size

Modified clays: lower surface area, larger particle size

Recent Research ResultsRecent Research Results

30

50

70

90

0 10 20 30

Filler content (%)

Tens

ile in

dex

(Nm

/g)

Control2.5Corn5Corn2.5Potato5Potato

30

50

70

90

0 10 20 30

Filler content (%)Te

nsile

inde

x (N

m/g

)

Control2.5Corn5Corn2.5Potato5Potato

Before Before CalenderingCalendering CalenderedCalendered

Handsheet Tensile StrengthHandsheet Tensile Strength

Control: 5% starch based on unmodified clay;i.e., at 10% clay in sheet: 0.5% starch in sheet (10 lb/t)

Ring Crush, Ring Crush, CalenderedCalendered Handsheets Handsheets

Can add at least 10-15% modified clay and get same ring crush

10

15

20

25

30

0.00 10.00 20.00 30.00

Filler content (%)

Rin

g C

rush

(lbf

), G

M

Control2.5Corn5Corn2.5Potato5Potato

Bulk of Bulk of CalenderedCalendered HandsheetsHandsheets

Potential for at least 10% filler increase without affecting bulk

1.0

1.1

1.2

1.3

0 10 20 30

Filler content (%)

Bul

k (c

m3 /g

)

Control2.5Corn5Corn2.5Potato5Potato

Brightness and Smoothness Brightness and Smoothness CalenderedCalendered Handsheets Handsheets

Improvement in brightness and smoothness with higher clay levelsModified clay has somewhat less impact due to larger particle size

smoother→

10

15

20

25

30

35

0 10 20 30

Filler content (%)

Brig

htne

ss (I

SO)

Control2.5Corn5Corn2.5Potato5Potato

3

4

5

6

0 10 20 30

Filler content (%)

Rou

ghne

ss (µ

m)

Control2.5Corn5Corn2.5Potato5Potato

smoother→

Improved Modified Clay Improved Modified Clay Preparation Procedure Preparation Procedure Prior to Spray Drying Prior to Spray Drying

• Starch cooked separately• Cooked starch mixed under high shear with

dry clay and water to desired solids and starch content – Range of 20-50% solids investigated– 2.5 or 5% starch based on clay

IPST Spray DryerIPST Spray Dryer

Lab S1 Spray DryerAndydroCopenhagen, Denmark

Spray Dryer EvaluationSpray Dryer Evaluation

• Shear viscosity measured for control clay and modified clay to screen slurries prior to spray drying– Control: 50% solids

unmodified clay – Modified clay: 20-

50% solids investigated

• Results: modified clay can be spray dried up to 40-45% clay (with 2.5% starch)

0102030405060708090

100

0 200 400 600Shear Rate

Visc

osity

(cP)

50% clay40-2.5corn40-2.5potato40-5corn40-5potato30-2.5corn30-2.5potato30-5corn30-5potato20-2.5corn20-2.5potato20-5corn20-5potato

Gas Temp (oC) Sample Feed rate (ml/min) Inlet Outlet

Mass yield (%)

20% Clay 24.5 210 120 72.0 20-2.5Corn 22.3 210 120 99.0 20-5Corn 25.3 210 120 88.1 20-2.5Potato 35.6 210 120 74.0 20-5Potato 24.6 210 120 82.1 50% Clay 27.5 210 120 79.7 30-2.5Corn 25.3 210 120 96.9 35-2.5Corn 17.3 210 120 95.1 40-2.5Corn 20.8 210 120 97.8 45-2.5Corn 7.5 210 120 92.6

Technology Transfer IssuesTechnology Transfer Issues

• Complete characterization of spray-dried modified clay– Particle size (IMERYS)

• Assess handsheet properties for spray-dried modified clay– Strength, optical properties (IPST)– Printing properties (IMERYS)

• Scale-up spray drying at IMERYS to produce large quantities for pilot trial

• Conduct pilot trial • Calculate economics for clay production, for use of modified

clay in mill• Meet with paper producers

Industrial PartnerIndustrial Partner’’s Evaluations Evaluation

•• Feasibility of producing the modified clay Feasibility of producing the modified clay economicallyeconomically

•• Characterization of sprayCharacterization of spray--dried clay and dried clay and calenderedcalendered handsheetshandsheets

•• Production of large quantities of sprayProduction of large quantities of spray--dried dried modified claymodified clay

Relevance to Industry Needs Potential Economic Benefits

• Leverage Georgia’s unique manufacturing capabilities in kaolin and SW pulp to develop a unique economic advantage for these two industries.

• Given pulp cost of $400/ton and new bonding filler cost of $150/ton, filler increase of 10% will save $22/ton fiber

• Reduced papermaking chemicals will save $10/ton• Projected average saving of $32/ton• 50-100% increase in the use of GA kaolin fillers in GA paper

industry• These benefits will allow Georgia’s paper industry to utilize GA

kaolin with reduce transportation costs and increase paper products quality.