1
Plastic in Packaging
Lesson 7
第 7课 塑料在包装中的应用
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,
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,
4
Plasticating Extruder
Ex i t
p o rt
Gea r re d u c e r
V a ri a b l e spe e d mo to r
F e e d t h ro a t
F e e d h o p p e r
Ho p p e r th ro a t
Co o l i n g j a c k e t
Sc re w
He a t e r b a n d s
Fig,10.2
5
A dj us tabl e
D i e L i p s
E x tr us i on
D i e
A dj us tabl e P r es s ur e
( R es tr i c tor ) B ar
E x tr ude r
Cast Film and Sheet Extrusion
Fig.10.4
6
E x t ru de r # 1
E x t ru de r # 2
E x t ru de r # 3
M ate ri a l # 1
M ate ri a l # 2
M ate ri a l # 3
Three-Layer Coextrusion
Fig.10.9
7
Extrusion Cast Film Line Layout
E x t ruder
E x t rusi on d i e C hi l l ro l l
E dg e tri m me r
Ma teri al ro l l
Fig.10.5
8
Machine Direction Orientation
R ot a tion x 1 x 3x 2 X 4
F r om e xtr ud er
castin g r oll s
Fig.10.8
9
Ext rud er
C as ti ng Rol l s
Ann ea l i ng Z on e
Ext rus i on Di e
T e nt er C l i ps
Cross Direction Orientation
Fig.10.8
10
Bub b l e
Blo w -u p a i r i n l e t
Coo l i n g a i r Coo l i n g a i r
Pla s ti c fro m e x tru d e r
Die l i p a d j u s ti n g b o l ts
Die Bod y
Die c o re
Fro s t l i n e
Bub b l e c o n s ta n tl y p u l l e d u p
Blown-film Die Cross-Section
Fig.10.6
The die is often rotated to prevent gauge bands
11
Three-layer Extrusion Blow Mold
Cut-away view
material 1
material 2
material 3
film bubble
12
Ex t ru d e r
Cir c u l a r
d i e
Ai r ri n g
In t e rn a l b u b b l e c o o l i n g
Pl a s ti c f i l m b u b b l e
Col l a p s i n g f ra m e
Upp e r n i p ro l l s
Sl i tt e r
Dua l ro l l
win d e r
Blown Film Line With Slitter
Fig.10.7
13
Blown Film Line Showing Die & Bubble
14
Injection Molding Extruders
Fig.10.10
15
Injection Molding Machine
Extruder
barrel
Feed
hopper
Mold
location
Extruders are sized by their clamping capacity
16
Three-Plate Injection Mold
Fig.10.12
17
Three-Plate Injection Mold
18
Parts With Attached Runners
9
The distance between the
sprue and the gate must be
exactly the same for every
cavity
19
Plastic Shrinkage and Sink Marks
Fig.10.16
Most commonly can be seen opposite closure threads
Sink marks over cup flange support ribs can cause
sealing problems
In t e n d e d d e s ig n
Sh rin k a g e = f x
Sh rin k a g e = 4 f x
A c t u a l p a r t p ro d u c e d
Sin k m a rk
3x
4x
X
20
Molding Undercuts
Fig.10.15
P e d e s t a l
p l u g
Ma i n b o d y r i n g
P e d e s t a l r i n g
h a l v e s
B o d y p l u g
Ga t e
21
Injection Molding Undercuts
22
Bottle-Making Terminology
Finish,That part of a bottle or jar that accepts
the closure
Parison,An initial shape that will be expanded into a
bottle or jar in a second step
Preform,Describes the parison when using injection
blow-molding
Moyle,The pinch-off trim piece from an extrusion
blow-molded bottle
23
Ne c k rin g i nse rt
Pin c h -of f i nse rt
F l ash po ck e t
M ol d ca vit y
M ol d g ui d e
pi n s
C oo l i ng
cha nn el s
Extrusion Blow Mold
Fig,10.20
24
Extrusion Blow Mold
R
1,Neck-ring insert
2,Cooling water ports
3,Cut-off insert
1
2
3
1
3
2
25
Extrusion Blow Molding (EBM)
Fig.10.18
26
Injection-Blow Molding Machine
27
Untrimmed EBM PP Bottle
R
3,Tail or pinch-off trim
1,Finish trim
2,Handle knock-out
1
2
3
28
Parison Expansion & Wall Thickness
Ini ti al pa ris o n e x pa ns i on i s e qual i n al l di re c ti ons w al l thi c k nes s
E x p and i ng paris on freez es the m om ent
i t to uc h es the c hi l l ed mo l d w al l
P ari s on co n ti nu es stre tch i ng a fter t he pa ris on c ente r f ree z es
P ari s on co n ti nu es stre tch i ng a fter t he pa ris on c ente r f ree z es
A s a res ul t,c orne r w al l thi c k n es s i s si gni f i c a ntl y redu c ed
Figure 10.24
29
Un if orm-W a ll e d Pa ri s o n Pro gram ed P aris on
Fig,10.22
Parisons and Bottle Wall Thickness
30
V a r iab le o p e n ing
co n trols p a r ison - wa l l
th i ckn e ss
Programmable Parisons
Fig,10.23
31
Examples of Coextruded Bottles
1 & 2 Reduced pigment on inner layer
3 Three layer bottle with U.V,barrier central layer
1 2 3
R
32
Injection-Blow Molding (IBM)
Fig.10.23
In j ec tio n
m ol d
B lo w m ol d
o p en c lo se d
P re fo rm e xp an d ed
to b l ow m ol d
P r ef or m c a rrie d
ov er o n c or e p in
A ir
33
Injection-Blow Molding Machine
Fig.10.27
B l o w p o s i t i o n
S t r i p
p o s i t i o n
P r e fo r m s
In je ct i o n m o ld
B lo w m o ld
S tr ip p e r p la te
E xt r u d e r
I n j e c t i o n
p o s i t i o n
r o ta t i n g
t a b l e
Co r e r o d
34
Injection-Blow Molding Machine
35
IBM Preforms and Container
R
36
Injection-Stretch Blow Molding (ISBM)
Fig.10.28
P r e f o r m an d cor e pi n
cl am pe d i n bl ow m ol d
C or e pi n m oves d ow n,
st r et chi ng pr ef or m
P r e f o r m bl ow n t o
con t a i n er s hap e
37
ISBM Preforms and Soda Bottles
R
38
Properties Imposed by Molding
R
39
EBM and IBM Compared
tooling one mold set two mold sets
mold cavities commonly 2 or 3 12 and more possible
secondary operations trim and regrind no trim or regrind
finish tolerances acceptable precision
unique finish designs limited possible
handleware common complex
thin-wall containers yes no
complex multi-layers yes difficult
large containers yes (e.g,drums) limited
base design requires pinch-off no pinch-off
Feature Extrusion B.M,Injection B.M,
Table10.2
Plastic in Packaging
Lesson 7
第 7课 塑料在包装中的应用
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,
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,
4
Plasticating Extruder
Ex i t
p o rt
Gea r re d u c e r
V a ri a b l e spe e d mo to r
F e e d t h ro a t
F e e d h o p p e r
Ho p p e r th ro a t
Co o l i n g j a c k e t
Sc re w
He a t e r b a n d s
Fig,10.2
5
A dj us tabl e
D i e L i p s
E x tr us i on
D i e
A dj us tabl e P r es s ur e
( R es tr i c tor ) B ar
E x tr ude r
Cast Film and Sheet Extrusion
Fig.10.4
6
E x t ru de r # 1
E x t ru de r # 2
E x t ru de r # 3
M ate ri a l # 1
M ate ri a l # 2
M ate ri a l # 3
Three-Layer Coextrusion
Fig.10.9
7
Extrusion Cast Film Line Layout
E x t ruder
E x t rusi on d i e C hi l l ro l l
E dg e tri m me r
Ma teri al ro l l
Fig.10.5
8
Machine Direction Orientation
R ot a tion x 1 x 3x 2 X 4
F r om e xtr ud er
castin g r oll s
Fig.10.8
9
Ext rud er
C as ti ng Rol l s
Ann ea l i ng Z on e
Ext rus i on Di e
T e nt er C l i ps
Cross Direction Orientation
Fig.10.8
10
Bub b l e
Blo w -u p a i r i n l e t
Coo l i n g a i r Coo l i n g a i r
Pla s ti c fro m e x tru d e r
Die l i p a d j u s ti n g b o l ts
Die Bod y
Die c o re
Fro s t l i n e
Bub b l e c o n s ta n tl y p u l l e d u p
Blown-film Die Cross-Section
Fig.10.6
The die is often rotated to prevent gauge bands
11
Three-layer Extrusion Blow Mold
Cut-away view
material 1
material 2
material 3
film bubble
12
Ex t ru d e r
Cir c u l a r
d i e
Ai r ri n g
In t e rn a l b u b b l e c o o l i n g
Pl a s ti c f i l m b u b b l e
Col l a p s i n g f ra m e
Upp e r n i p ro l l s
Sl i tt e r
Dua l ro l l
win d e r
Blown Film Line With Slitter
Fig.10.7
13
Blown Film Line Showing Die & Bubble
14
Injection Molding Extruders
Fig.10.10
15
Injection Molding Machine
Extruder
barrel
Feed
hopper
Mold
location
Extruders are sized by their clamping capacity
16
Three-Plate Injection Mold
Fig.10.12
17
Three-Plate Injection Mold
18
Parts With Attached Runners
9
The distance between the
sprue and the gate must be
exactly the same for every
cavity
19
Plastic Shrinkage and Sink Marks
Fig.10.16
Most commonly can be seen opposite closure threads
Sink marks over cup flange support ribs can cause
sealing problems
In t e n d e d d e s ig n
Sh rin k a g e = f x
Sh rin k a g e = 4 f x
A c t u a l p a r t p ro d u c e d
Sin k m a rk
3x
4x
X
20
Molding Undercuts
Fig.10.15
P e d e s t a l
p l u g
Ma i n b o d y r i n g
P e d e s t a l r i n g
h a l v e s
B o d y p l u g
Ga t e
21
Injection Molding Undercuts
22
Bottle-Making Terminology
Finish,That part of a bottle or jar that accepts
the closure
Parison,An initial shape that will be expanded into a
bottle or jar in a second step
Preform,Describes the parison when using injection
blow-molding
Moyle,The pinch-off trim piece from an extrusion
blow-molded bottle
23
Ne c k rin g i nse rt
Pin c h -of f i nse rt
F l ash po ck e t
M ol d ca vit y
M ol d g ui d e
pi n s
C oo l i ng
cha nn el s
Extrusion Blow Mold
Fig,10.20
24
Extrusion Blow Mold
R
1,Neck-ring insert
2,Cooling water ports
3,Cut-off insert
1
2
3
1
3
2
25
Extrusion Blow Molding (EBM)
Fig.10.18
26
Injection-Blow Molding Machine
27
Untrimmed EBM PP Bottle
R
3,Tail or pinch-off trim
1,Finish trim
2,Handle knock-out
1
2
3
28
Parison Expansion & Wall Thickness
Ini ti al pa ris o n e x pa ns i on i s e qual i n al l di re c ti ons w al l thi c k nes s
E x p and i ng paris on freez es the m om ent
i t to uc h es the c hi l l ed mo l d w al l
P ari s on co n ti nu es stre tch i ng a fter t he pa ris on c ente r f ree z es
P ari s on co n ti nu es stre tch i ng a fter t he pa ris on c ente r f ree z es
A s a res ul t,c orne r w al l thi c k n es s i s si gni f i c a ntl y redu c ed
Figure 10.24
29
Un if orm-W a ll e d Pa ri s o n Pro gram ed P aris on
Fig,10.22
Parisons and Bottle Wall Thickness
30
V a r iab le o p e n ing
co n trols p a r ison - wa l l
th i ckn e ss
Programmable Parisons
Fig,10.23
31
Examples of Coextruded Bottles
1 & 2 Reduced pigment on inner layer
3 Three layer bottle with U.V,barrier central layer
1 2 3
R
32
Injection-Blow Molding (IBM)
Fig.10.23
In j ec tio n
m ol d
B lo w m ol d
o p en c lo se d
P re fo rm e xp an d ed
to b l ow m ol d
P r ef or m c a rrie d
ov er o n c or e p in
A ir
33
Injection-Blow Molding Machine
Fig.10.27
B l o w p o s i t i o n
S t r i p
p o s i t i o n
P r e fo r m s
In je ct i o n m o ld
B lo w m o ld
S tr ip p e r p la te
E xt r u d e r
I n j e c t i o n
p o s i t i o n
r o ta t i n g
t a b l e
Co r e r o d
34
Injection-Blow Molding Machine
35
IBM Preforms and Container
R
36
Injection-Stretch Blow Molding (ISBM)
Fig.10.28
P r e f o r m an d cor e pi n
cl am pe d i n bl ow m ol d
C or e pi n m oves d ow n,
st r et chi ng pr ef or m
P r e f o r m bl ow n t o
con t a i n er s hap e
37
ISBM Preforms and Soda Bottles
R
38
Properties Imposed by Molding
R
39
EBM and IBM Compared
tooling one mold set two mold sets
mold cavities commonly 2 or 3 12 and more possible
secondary operations trim and regrind no trim or regrind
finish tolerances acceptable precision
unique finish designs limited possible
handleware common complex
thin-wall containers yes no
complex multi-layers yes difficult
large containers yes (e.g,drums) limited
base design requires pinch-off no pinch-off
Feature Extrusion B.M,Injection B.M,
Table10.2
