Cast Film Technology for Processing of Recycled PET Film Technologyfor... · Cast Film Technology for Processing of Recycled PET PET Recycling Forum 2008, Moscow, 12th February 2008

Cast Film TechnologyCast Film Technologyfor Processing of Recycled PETfor Processing of Recycled PET

PET Recycling Forum 2008, Moscow, 12th February 200 8PET Recycling Forum 2008, Moscow, 12th February 200 8

Dr. Stefan HoffmannDr. Stefan Hoffmann

© Brückner2

Headquarters: Siegsdorf, Germany

Turnover: 20 Mio. EUR

Brückner Formtec Company Profile

PET Roll Stack:

Thickness: 150 – 1,800 µm

Width: 1,600 – 2,700 mm

Output: 1,200 – 3,000 kg/h

Key Products:

PET Cast:

Thickness: 100 – 800 µm

Width: 1,600 – 2,200 mm

Output: 2,000 – 5,000 kg/h

CPP:

Thickness: 20 – 150 µm

Width: 3,600 – 6,000 mm

Output: up to 2,500 kg/h

Main characteristics: ���� High Productivity ���� Energy Savings

© Brückner3

Members of the Brückner Group

Brückner Maschinenbaufounded in 1960

Brückner Formtecfounded in 2001

Brückner Biotecfounded in 2006

Brückner Servtecfounded in 2003

KIEFEL GmbHacquired in 2007

KIEFEL Extrusion GmbH acquired in 2007

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Brückner Worldwide Sales & Service Network

U.S.A.

MEXICO

BRAZIL

ARGENTINA

UAEINDIA

INDONESIA

CHINA

RUSSIA

SLOVAKIACZECH REPUBLIC

AUSTRIAFRANCE

SWITZERLAND

THE NETHERLANDS

GERMANY

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Market for A-PET Films

� Average annual growth rate > 12%

� Packaging

● Simple thermoforming applications

� Food and non-food clamshells

� Blister packs

� Strawberry punnets

� Folded boxes

● FFS (form–fill–seal) base web

� food packaging

Brückner Formtec Concept is well acceptedin this high volume/low cost market.

© Brückner6

Recent Market Developments

Use of PET Reclaim (PCR-CSD) in Packaging Applicati ons

� Drivers

● High material costs (approx. 80 % of production costs)

● Price inflation due to market growth

� Constraints

● Acceptance of recycled material in food application (→ legal regulations)

● Technical capabilities

� Contamination ↔ Filter concept

� Moisture content ↔ Energy for drying

� The developed Brückner Formtec concept for PET food packaging

is capable of processing approx. 100 % of PET recla im (PCR-CSD).

© Brückner7

Basis of Brückner Formtec Concept

� Technical capability:

● Twin screw technology available

- with modification in vacuum technology

● Filter concept

- continuous filtration with backflushing

10 % Coex layer: virgin PET (food contact)

10 % Coex layer: virgin PET (food contact)

80 % Core layer: up to 100 % PET (PCR-CSD)

� Premises:

● Use of PCR-CSD is permitted in food packaging

● Direct contact to food only for virgin material

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Bottle Flakes Concept- Part 1 -

Blown Bottles / Returned Packaging:● IV = 0.80 dl/g● transparent● coloured

Bottle Flakes:● Bulk density ρ = 280 – 350 kg/m³● IV approx. 0.72 – 0.75 dl/g● Moisture content about 5,000 ppm● Material mixture (transparent + coloured)● High degree of contaminants:

Paper & PP (labels); Glue (labels); PE (bottle caps); Aluminium (yoghurt cups); other polymers (PVC, PS, etc.)

Grinding+ Washing

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Bottle Flakes Concept- Part 2 -

Film Coextrusion Line:● Twin screw extrusion

● Continuous filtration systemincl. backflushing system

● Narrow tolerances

● Rollstack or electro-pinning

3-layer CoextrusionCapacity: 1,300 – 5,000 kg/h

Film width: up to 2.4 mThickness range: 100 – 1200 µm

Typical layer ratio: 10 / 80 / 10 %

no predryingno crystallizationno pelletizationno purification

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Typical Material Specificationsfor PCR -CSD PET Bottle Flakes

● Intrinsic viscosity: 0.72 – 0.80 dl/g

● Colour: amorphous: transparent with haze

● Specific gravity: 1,300 kg/m³● Melt density: 1,150 kg/m³

● Bulk density: 230 – 500 kg/m³

● Moisture content: ≤ 5,000 ppm● Contamination PVC: max. 10 ppm

Aluminum: max. 20 ppm

Dust: max. 1,000 ppmGlue: max. 20 ppm

Polyolefines: max. 20 ppm

Chemicals: max. 20 ppmColoured PET-Flakes: max. 50 ppm

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Line Concept- Example -

Low Energy andUtility Consumption

Twin Screw Extrudera. degassing stationsb. dry vacuum systemc. high torque motor

Continuous Filtration Systemd. meltpumpse. melt filtrationf. post filter

High Performance Rollstackg. adjustable crowning roller

highly stiff framehigh cooling capacity

Efficient andContinuous Filtration

Stable and ConsistentNarrow Tolerances

c a a

b

d e f d

g

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Twin Screw Extrusion without Predrying

� Twin Screws● No predrying (up to 5,000 ppm H2O)

● High reclaim content (up to 100 %)

● Energy saving

(SSE + Drying: ≈ 0.52 kWh/kg; TSE: ≈ 0.35 kWh/kg)

� Vacuum system● Two-stage system

● Dry running

● Modular

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Semi-Continuous Melt Filtration Process

Double piston screen changer

[Kreyenborg]

� During backflushing 75 % of filter area permanently available

� Pressure fluctuations during

backflushing� Second melt pump equalizes

pressure at die head

time

pres

sure

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Continuous Melt Filtration Process

[Gneuss Kunststofftechnik]

Rotary disc screen changer

� Continuous tacting� Pressure fluctuations of same order of

magnitude as for semi-continuous filtration

after second melt pump

1 – Screen exchange position 2 – Cavity3 – Backflushing piston 4 – Active screen area5 – Rotation direction

time

pres

sure

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Polishing Stack (Roll Stack)

10 2

C1C0 C2

contact gap

� Horizontal 3-roll polishing stack� High cooling capacity� Polishing roll with adjustable crowning

● uniform distribution of the melt (JuBo technology)� Second cooling roller

● gap between C1 and C2 (no deflection)

� Thickness range 150 – 1,800 µm● High polishing (line) pressures for thin films

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Casting Unit (Chill Roll)

� Cast Film process with Pinning Technology

� Extrusion output up to 5,000 kg/h

� Highest output for highest productivity

� Thickness range 100 – 800 µm

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Comparison PET Roll Stack / Chill Roll

100 – 800 µm

Single side polishedBoth sides polishedOptical properties

Single/Twin ScrewSingle/Twin ScrewExtrusion

150 – 1,800 µmThickness range

up to 150 m/minup to 60 m/minProduction speed

Output is limited by cooling capacity of main cooling roller

Diameter of cooling roller is not limited

Output is limited by cooling capacity of main cooling roller

Cooling roller diameter is limited by geometry –die has to be close enough to the nip

Speed limitations

600 – 2,400

up to 3,000 kg/h

Roll Stack

600 – 1,900Net film width

up to 5,000 kg/hOutput

Chill roll

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Conclusion

� High-performance systems for production of A-PET and PET Reclaim meet the requirements for an attractive price/performance ratio

� Filtration concept permits use of up to 100 % PET bottle reclaim

� High system throughput at high quality level

� Integrated process control helps to reliable adjust all components of the system to the conditions needed for cast film production

� Flexibility and productivity of the system concept puts PET film producers in position to satisfy changing requirements resulting from global competition

© Brückner19

Thank youThank youfor your attention.for your attention.

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