1 Omya AG

Calcium Carbonate in Blown HDPE Film

New Developments to increase Productivity and Profitability

Version 2.1 - October 2003

2 Omya AG

CaCO3 in Polyolefines : Oriented Lamellae

Polyolefines Matrix

CaCO3 Particles

Bridge(oriention of lamellea)

Oriented Layer

3 Omya AG

Estimation of Matrix Ligament Thickness

=d x[ ( / 6 )1/3 - 1] x exp[(ln )2]β σΛ π φd = number average geom.. mean diam. of particles

β = geom.. constant depending on assumed packing :1.0 for cubic lattice, 1.09 for body-centered cubic,1.12 for face-centered cubic

φ = volume fraction of particles

σ = geom.. std dev. of particle size distribution

Ref : Bartczak et al. Polymer 40 (1999) 2331

Brittle Behavior

When ligament thickness is larger than 2 times the thickness

of the oriented crystallization layer around the particles.

Ref : Bartczak et al. Polymer 40 (1999) 2331

Filler / Rubber Particle

Bulk Matrix

Oriented Layer

Ductile Behavior

When ligament thicknessis less than 2 times the thickness

of the oriented crystallization layeraround the particles

andmaterial with reduced plastic resistance

percolates through the blend.

* Connecting lines show orientation of lamellae ininter-particle ligaments

8 Omya AG

Objective

To introduce CaCO3 in PE Blown Film in order to improve profitability by enhancement of productivity and

mechanical properties.

9 Omya AG

New Concept - Method’s Description

1- To produce a concentrate of a fine coated CaCO3

To use the base resin from film producer as the carrier for a 65% to 75% Masterbatch

2- To introduce this Masterbatch till 25 % CaCO3 in the film extrusion line

Increase the screw rpm to maximise the benefits of CaCO3

No additional changes are required

10 Omya AG

Trials & Process Conditions

KIEFEL EXTRUDER COMPEX 80 SAScrew Size : 80 mm X 25 DDie Diam : 200 mm X 1.4IBC System with Aero-CoolOutput without CaCO3 : 260 kg/hr.Specific Screw Output : 2,56 Kg/rpm/hr

Film Extrusion Line

Basic Polymer Blend

80% Unimodal HDPE + 15% butene LLDPE + 5% White

Masterbatches 65 % Omyafilm + LLDPE

11 Omya AG

Process Conditions

Layflat Width 1440 mm

Initial Thickness (without CaCO3) : 14 µ

then downgauged Film to work at identical Weight

by adding 10 %,17,5 % and 25 % of CaCO3

Production Programme

12 Omya AG

Production Enhancement

• Melt Pressure

By introducing CaCO3 in the screw, melt pressure dropsallowing an increase of screw speed.

Lower manufacturing cost per unit (bag)

13 Omya AG

458

bar

550

bar

505

bar

476

bar

-16,73%

-13,45%

-8,18%

0,00%

400 bar

425 bar

450 bar

475 bar

500 bar

525 bar

550 bar

575 bar

0% 5% 10% 15% 20% 25% 30%

CaCO3 Pigments

-27,3%

-22,7%

-18,2%

-13,6%

-9,1%

-4,5%

0,0%

Variation Melt Pressure

14 Omya AG

Production Enhancement

• Higher Spec. Output

internal volume of the screw will be reduced

viscosity of the blend will be reduced

higher melt homogeneity

Increase of the blend density

higher efficiency of the grooved feed section of the extruder

15 Omya AG

Variation Specific Output

3,21

3,002,87

2,57

1,1591,0951,0380,97

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

0 % 5 % 10 % 15 % 20 % 25 %

CaCO3 Pigments

Mix

ture

Den

sity

/ Sp

ec O

utpu

t

Spec. Output [kg/h/rpm]

Mixture Density [kg/dm3]

+ 25,2%

+19,5%

16 Omya AG

Production Enhancement

• Bubble stability improved

Faster cooling of blown bubble thanks to higher thermal conductivity of CaCO3

• Neck Height could be increased from 8 X Die Diam to 13 X.

17 Omya AG

Thermal Conductivity

-

0.50

1.00

1.50

2.00

2.50

3.00

[W/ M°K]

PP LLDPE HDPE CaCO3

18 Omya AG

Mechanical Properties Enhancement

• Increased Dart Drop Impact Strength

Toughening of PE matrix thanks to addition of CaCO3.

Possibility of down-gauging

19 Omya AG

12,6

19 g

/µ

16,1

00 g

/µ

16,9

00 g

/µ

17,2

50 g

/µ

0,00%

27,59%

36,70%33,93%

10 g/µ

11 g/µ

12 g/µ

13 g/µ

14 g/µ

15 g/µ

16 g/µ

17 g/µ

18 g/µ

0,0% 2,5% 5,0% 7,5% 10,0% 12,5% 15,0% 17,5% 20,0% 22,5% 25,0%

CaCO3 Pigments

-20,8%

-14,8%

-8,9%

-3,0%

3,0%

8,9%

14,8%

20,8%

26,7%

32,6%

38,5%

Variation Dart Drop Test

20 Omya AG

Mechanical Properties Enhancement

• Increased Dart Drop Impact Strength

Toughening of PE matrix thanks to addition of CaCO3.

Possibility of down-gauging

• Higher Elmendorf Tear Strength

21 Omya AG

7,71

5 m

N/µ

10,2

50 m

N/µ

11,2

54 m

N/µ

10,7

80 m

N/µ

0,00%

32,86%

45,87% 39,73%

7 mN/µ

8 mN/µ

9 mN/µ

10 mN/µ

11 mN/µ

12 mN/µ

0,0% 2,5% 5,0% 7,5% 10,0% 12,5% 15,0% 17,5% 20,0% 22,5% 25,0%

CaCO3 Pigments

-9,3%

0,0%

9,3%

18,6%

27,9%

37,2%

46,5%

Variation Elmendorf MD

22 Omya AG

Variation Elmendorf TD

75,4

23 m

N/µ

110,

120

mN

/µ

130,

116

mN

/µ

128,

000

mN

/µ

0,00%

69,71%72,52%

46,00%

60 mN/µ

70 mN/µ

80 mN/µ

90 mN/µ

100 mN/µ

110 mN/µ

120 mN/µ

130 mN/µ

140 mN/µ

0,0% 2,5% 5,0% 7,5% 10,0% 12,5% 15,0% 17,5% 20,0% 22,5% 25,0%

CaCO3 Pigments

-20%-12%-4%4%12%20%29%37%45%53%61%70%78%

23 Omya AG

Mechanical Properties Enhancement

• Increased Dart Drop Impact Strength

Toughening of PE matrix thanks to addition of CaCO3.

Possibility of down-gauging

• Higher Elmendorf Tear Strength

• Higher secant modulus

Helps in bag production

•Better folding and winding on bag lines

24 Omya AG

Tensile Strength at Break MD

0 N/mm2

10 N/mm2

20 N/mm2

30 N/mm2

40 N/mm2

50 N/mm2

60 N/mm2

0% 10% 17,5% 25%CaCO3 Pigments

25 Omya AG

Tensile Strength at Break TD

0 N/mm2

10 N/mm2

20 N/mm2

30 N/mm2

40 N/mm2

50 N/mm2

60 N/mm2

0% 10% 17,5% 25%CaCO3 Pigments

26 Omya AG

Elongation at Break MD

0 %

100 %

200 %

300 %

400 %

500 %

600 %

0% 10% 17,5% 25%CaCO3 Pigments

27 Omya AG

Elongation at Break TD

0 %

100 %

200 %

300 %

400 %

500 %

600 %

0% 10% 17,5% 25%CaCO3 Pigments

28 Omya AG

Isotropy : CaCO3 Balances Polymer’s Orientation

TD

.MD

MD

TD

Neck Height 8X Die

With CaCO3

.Neck Height 12X Die

Without CaCO3

29 Omya AG

Isotropy : Elmendorf TD/MD

16,501

-57,07

13,672

31,849

25,433

-20,15

-48,19-60-50-40-30-20-10

010203040

0% 10% 17,50% 25%

%

Rate TD/MDAver. Decrease Rate

CaCO3

30 Omya AG

Sealing

Sealing Strength with Omyalene 2021 P

0

2

4

6

8

10

12

0 5 10 15 20 25 30

CaCO3 Pigments [%]

Seal

ing

Stre

ngth

[N/1

5mm

]

Sealing Strength 160° [N/15mm]]Sealing Strength 150° [N/15mm]]Sealing Strength 140° [N/15mm]]Sealing Strength 130° [N/15mm]]Sealing Strength 120° [N/15mm]]

15µm monolayer 82% HDPE 13% LLDPE 5% White MB

change HDPE for CaCO3

keep LLDPE const.

31 Omya AG

Mechanical Properties Enhancement Summary

CaCO3 will bring a homogeneous and isotropic film with upgraded characteristics.

Decreased orientation and equalisationof MD and TD propertiesBetter bubble stabilityNeck length can be increased up to13 X die diameterBUR can be reduced by 10% and abigger die can be used, increasing outputImproved film flatness and thicknesstolerancesBetter roll qualityBetter PrintabilityFaster welding

32 Omya AG

Mechanical Properties Enhancement Summary

Dart drop increased by up to 45%Elmendorf MD tear increased by up to 150%Elmendorf TD tear increased by up to 140%

Thinner film with equal mechanical properties

OR

Same thickness with much improved mechanical properties

33 Omya AG

Process Enhancement Summary

Lower melt pressuresHigher specific screw outputBetter bubble stabilityFaster cooling due to higher thermal conductivity of CaCO3

Better melt homogeneity

=

Higher Extruder Output by up to1% per percent CaCO3

34 Omya AG

Productivity Enhancement Summary

Potential raw material cost savings

Potential to compete with higher

performance resins

Reduction of TiO2 Masterbatch

Elimination of blocking problems

Lower extrusion costs

35 Omya AG

Final Costs Calculation

0 % CaCO3 10% CaCO3 17.5 % CaCO3 25 % CaCO3

Production (mT/Year) 2.660 2.926 3.126 3.325

Total Fixed Costs 236.875 € 236.875 € 236.875 € 236.875 €

Variable Costs 228.359 € 234.147 € 237.660 € 240.878 € Polymer Costs 2.056.111 € 2.246.466 € 2.361.295 € 2.471.805 €

Total Costs 2.521.345 € 2.717.488 € 2.835.830 € 2.949.558 € Price/Kg of Good Film 0,95 € 0,93 € 0,91 € 0,89 €

0,00% -3,88% -5,71% -7,51%0 € - 91.472 € - 165.130 € - 242.442 €

Total Saving Money

36 Omya AG

Additional Benefits

CaCO3 cleans the die and extruder

Shorter changeover times

CaCO3 is an ecological product

Replacing polymer

Neutralising flue gases so preventing acid rain

37 Omya AG

Additional Benefits

Incineration of bags containing CaCO3 decreases CO2 emission

1 Kg of PE gives 2.917 Kg CO2

1 Kg of bags containing 20 % CaCO3 gives 2,602 Kg CO2

- 17,2 % CO2

38 Omya AG

Summary

• Improve physical properties

• Competitive with higher performance resins

• Potential for down-gauging film

• Potential raw material cost savings

• Higher output rates

• Lower manufacturing costs

• Contribute to a cleaner environment