《包装技术基础》（双语版） Lesson 7 Plastic in Packaging

Lesson 7 Plastic in Packaging 第7课塑料在包装中的应用

1 Plastic in Packaging Lesson 7 第7课 塑料在包装中的应用

Polymer Properties Depend On 1. What elements are in the molecule? 2. What size(molecular weight) is the molecule? 3. Is the molecule polar or non-polar? 4. What shape is the molecule? 5. What is its thermal history? 6. What is its mechanical history?

2 1. What elements are in the molecule? 2. What size (molecular weight) is the molecule? 3. Is the molecule polar or non-polar? 4. What shape is the molecule? 5. What is its thermal history? 6. What is its mechanical history? Polymer Properties Depend On:

Deformation and Thermal History Room temperature deformation is permanent Plastics stretched at about t and cooled slowly are heat stable Plastics stretched at about Ta and cooled quickly have "memory and will shrink if reheated

3 Deformation and Thermal History Room temperature deformation is permanent. Plastics stretched at about Tg and cooled slowly are heat stable. Plastics stretched at about Tg and cooled quickly have “memory” and will shrink if reheated

Plasticating Extruder 产 Gear reducer Feed hopper Heater bands /Feed throat LF ANSSSYSSSSSSL,Exit port Hopper throat Screw Cooling jacket Variable speed motor Fig.10.2

4 Plasticating Extruder Exit port Gear reducer Variable speed motor Feed throat Feed hopper Hopper throat Cooling jacket Screw Heater bands Fig. 10.2

Cast Film and sheet Extrusion Extruder Eⅹ trusion Die Adjustable Pressure (Restrictor) Bar Adjustable Die Lips Fig 10.4

5 Adjustable Die Lips Extrusion Die Adjustable Pressure (Restrictor) Bar Extruder Cast Film and Sheet Extrusion Fig.10.4

Three-Layer Coextrusion Extruder #1 Material #F1 Extruder #2. Material ##2 Material #3 Extruder #3 Fig.10.9

6 Extruder #1 Extruder #2 Extruder #3 Material #1 Material #2 Material #3 Three-Layer Coextrusion Fig.10.9

Extrusion Cast Film Line Layout Extrusion die Chill roll Material roll Extruder Edge trimmer ig.10.57

7 Extrusion Cast Film Line Layout Extruder Extrusion die Chill roll Edge trimmer Material roll Fig.10.5

Machine direction Orientation From extruder casting rolls Rotation x1×2X3X4 Fjg.10.8

8 Machine Direction Orientation Rotation x 1 x 2 x 3 X 4 From extruder casting rolls Fig.10.8

Cross Direction Orientation Eⅹ trusion die Extruder Casting Rolls Tenter Clips-Annealing Zone Fig10.8

9 Extruder Casting Rolls Annealing Zone Extrusion Die Tenter Clips Cross Direction Orientation Fig.10.8

Blown-fillm Die cross-section ↑个个个个个个 Bubble constantly pulled up Bubble Frost line Cooling air ← Cooling air Dⅰ e core Die lip adjusting bolts Die bod Plastic from extruder Blow-up air inlet he die is often rotated to prevent gauge bands ig106

10 Bubble Blow-up air inlet Cooling air Cooling air Plastic from extruder Die lip adjusting bolts Die Body Die core Frost line Bubble constantly pulled up Blown-film Die Cross-Section Fig.10.6 The die is often rotated to prevent gauge bands