Extrusion Coating Extrusion Coating Dies and FeedblocksDies and Feedblocks

Gary Oliver

Extrusion Dies Industries, LLC

Understanding Application Needs

““If we do not learn from history, we are doomed to repeat it.If we do not learn from history, we are doomed to repeat it.””George SantayanaGeorge Santayana

Important Considerations for Extrusion Coating Applications

• Trouble-free coating width variation for versatility and efficiency

• Ability to reduce edge bead size to minimize waste• Precise control of coat-weight uniformity so that

desired mono-layer or coextruded physical properties are achieved with the least amount of material

The Extrusion Coating Die

• Precisely distributes the extrudate across a changeable exit width.

• Enable easy coating width changes.• Manipulates the edge bead effect for efficient use of

the coating materials.

External Deckles

Jyohoku Seiko Co., Ltd., Tokyo, Japan - Patent 4,248,579 8-February-1981

Internally Deckled Bead Reduction DieInternally Deckled Bead Reduction Die

Internally Deckled Bead Reduction DieInternally Deckled Bead Reduction Die

Jyohoku Seiko Co., Ltd., Tokyo, Japan - Patent 5,395,231 7-March-1995

Internally Deckled Bead Reduction DieInternally Deckled Bead Reduction Die

Cloeren EBR™

Internally Deckled Extrusion Coating Die

• Flow channel is streamlined at all operating widths. • Internal blades can be adjusted to minimize edge

bead size.

Internal Only Deckles

Can require rigorous procedures to adjust and maintain

Advantages of Internal/External Deckle

• The internal deckles can be repositioned during extrusion and provide the primary seal at the die lip.

• The external deckle provides a secondary seal and eliminates the need to clamp the deckle with the flex lip.

The Deckle Mechanism

• A guide system drives the movement of both the internal and external deckle components.

• Solid deckle blades fill the die channel for a more effective seal.

Internally Deckled DieInternally Deckled DieEach Component Independently AdjustableEach Component Independently Adjustable

Deckle ComponentsDeckle Components

Manifold Manifold DeckleDeckle

Secondary Secondary DeckleDeckle

Deckle RodDeckle Rod

Lip FlagLip Flag

External External DeckleDeckle

Edge Control

• Internal deckles can be stepped to reduce the edge bead size.

Edge Control

Edge Control

Particle Path As It Relates To Internal Deckle Position

Deckle Position Data

Accumulated Material

Understanding Die Swell

Polymer Flow

Lip Land Length

• Internally deckled dies utilize various land lengths at the exit of the die.

3mm lip land 12mm lip land

Experimentally Determine Land Length Impact

• Examine Land Length– As related to Pressure– As related to Die Swell

• Examine Lip Gap– As related to Pressure– As related to Die Swell

Test Instrument

Thermo Scientific HAAKE PolyLab

Capillaries for Test Device

Land Length

3 mm6 mm

12 mm19 mm25 mm

Capillary Diameter - 0.7 mm

• All rates converted to kg/h/mm die slot.

• Average rate 1.0kg/h/mm die slot.

Draw Down Device

Draw Down Rate = 25 m/min

Testing Rates

• All rates converted to kg/mm slot opening– Lip gap initial set point 0.75 mm– Average rate 1.0 kg/mm slot opening– 2000 mm slot = 2000 kg/hr– Range 0.1 kg/mm – 6.0 kg/mm

• 2000 mm slot opening–200 kg/hr minimum–6000 kg/hr maximum

Resins Tested

• INEO4S 18R430 15.0 998 69 250 17• INEOS 19N730 7.5 1056 73 326 22• INEOS 2OP730 8.8 1100 76 385 27• INEOS 23L430 4.1 1402 97 495 34• DOW 5004 4.2 1276 88 435 30

Resin Grade MFI 25 mm Land Pressure 3 mm Land PressurePSI Bar PSI Bar

• Higher pressure can lead to leakage issues and may limit output.

Test Photos

25 mm Capillary: No visible die swell but excessive back pressure.

12 mm Capillary: Minimal die swell with reasonable back pressure.

3 mm Capillary: Excessive die swell and low back pressure.

• Lip Land Length Significantly Impacts Die Swell– Short land lengths produce greater die swell– Die swell impacts die lip buildup

• Lip Land Length Impact Pressure– Deckle Sealing

• Larger Gap Decreases Die Swell– Increasing die gap reduces swell– Increasing die gap increases DDR– Increasing gap can increase neckin

Conclusions

Die Lip Face

• Precise release point for the polymer

• Minimizes contact with the lip face

Lip Edge

Die Lip Gap Adjustment

• Manual Adjustment– Sliding lip adjustment– Flex lip adjustment

• Automatic Profile Control– Thermal die bolt– Open or Closed loop feedback

Automatic Profile Control

Thermal actuators are the common method for lip adjustment.

Coextrusion Feedblock Systems

Structure Arrangement Capability Fixed or Variable Geometry Design

Fixed Geometry Cross Sectional View

Davis Standard – BC Micro-Layer Feedblock

Cloeren Vane Feedblock

Adjustable Feedblocks

Product Changeover

Exchangeable selector spools have a slip fit and

allow convenient changes to the layer sequence.

Selector Spools

Product Changeover

Bolted plates with metal to metal seals ensure leak-free performance and provide streamlined (fully round) flow paths.

Selector Plates

Internal View of Flow Channel

Summary• Solid deckle blade design completely fills the die

channel.• External deckles back-up the internal deckle.• Internal deckles can be stepped to reduce the edge

bead size.• A 12mm lip land provides good distribution control,

effective deckle sealing and reduced die swell. This prevents lip build-up and streaks.

• Automatic lip control produces rapid and precise automatic coat weight control.

• Feedblocks are used to form composite coating structures which produce desirable performance properties without multi-pass lamination or coating.