flexible packaging laminates
DESCRIPTION
Lesson 8. Flexible Packaging Laminates. 第 8 课 软包装复合材料. Contents:. Laminates Aluminum Foil Vacuum Metallizing Other Inorganic Coating Laminate Structural and Physical Properties Flexible Bags, Pouches and Sachets Sealability Barrier Properties Laminating Processes - PowerPoint PPT PresentationTRANSCRIPT
1
Flexible Packaging Laminates
Lesson 8
第 8 课 软包装复合材料
2
Contents:• Laminates • Aluminum Foil• Vacuum Metallizing• Other Inorganic Coating• Laminate Structural and Physical Properties• Flexible Bags, Pouches and Sachets • Sealability• Barrier Properties• Laminating Processes • Specifying Laminates• Examples of Laminates
3
Plasticating Extruder
E x itport
G ear reducer
Variab le speed m o to r
F eed throa tF eed hopper
H opper throa tC oo ling jacket
S crew
H ea te r bands
4
Adjustable D ie Lips
Extrusion D ie
Adjustable P ressure (Restrictor) Bar
Extruder
Cast Film and Sheet Extrusion
5
Extruder #1
Extruder #2
Extruder #3
M ateria l #1
M ateria l #2
M ateria l #3
Three-Layer Coextrusion
6
Extrusion Cast Film Line Layout
E xtrude r
E x trus ion d ie C h ill ro ll
E dge trim m er
M ate ria l ro ll
7
Machine Direction Orientation
R otation x 1 x 3x 2 X 4
From extruder casting ro lls
8
E xtrude r
C asting R o lls
A nnea ling Zone
E xtrus ion D ie
Ten te r C lips
Cross Direction Orientation
9
B ubble
B low -up a ir in le t
C oo ling a ir C oo ling a ir
P las tic from extrude r
D ie lip ad jus ting bo lts
D ie B ody
D ie co re
F rost line
B ubble cons tantly pu lled up
Blown-film Die Cross-Section
10
Three-layer Extrusion Blow Mold
Cut-away view
material 1
material 2
material 3
film bubble
11
E xtrude r
C ircu lar d ie
A ir ring
In te rna l bubb le coo ling
P las tic film bubb le
C o llapsing fram e
U pper n ip ro lls
S litte rD ua l ro ll w inde r
Blown Film Line With Slitter
12
Blown Film Line Showing Die & Bubble
13
Aluminum Foil
Household foil is typically 17.5 m (0.0007 inches)
Available in gauges as low as 7 m (0.00028 inches)
Pin holing is present below 12 m (0.0005 inches)
Foil is susceptible to flex cracking
Most foils are supported with plastic and/or paper
Unsupported foil used for some lid-stock & tablet push-through packaging
14
Intact foil is a 100% barrier to all gases
Best deadfold properties
Easily punctured (tamper evidence)
Reflective of radiant heat
Conductive (induction sealing)
Decorative appeal: all reflective metallics are aluminum
Aluminum Foil Characteristics
15
Foil Packaging Applications
Unsupported foil, non-sealablee.g. confection and cheese wraps
Unsupported foil, heat sealablee.g. lidding stock, pharmaceutical tabletbacking material
Supported foil, non heat sealablee.g. decorative wraps, label stock
Supported foil, heat sealablee.g. high barrier pouches and sachetslidding stock, retort pouches
16
Aluminum Vacuum Metallizing
Vacuum line
U nw ind ro ll
A lum inum vaporC eram ic boat
R ew ind ro ll
A lum inum w ire C hilled ro ll
17
Provides reflective metallic appearance
Improves moisture, aroma, light and oxygen barrier
Oxygen barrier improved: up to fifty times for OPP, up to ten times for PET
Static dissipative applications
OPP, PET, & PA (nylon) most common packaging films
Aluminum Metallized Film
18
Why Laminate?
There is no perfect, universal packaging material
Laminates assemble materials with individually
desirable properties to create an optimum material
Laminate: A product made by bonding together two or more materials
19
Mechanical properties
tensile strength stiffness
coefficient of friction use temperatures
elongation formability
Laminate Properties
Barrier properties as required
oxygen barrier essential oil barrier
water vapor barrier light barrier
20
Laminate Properties
Sealabilitymost flexible packaging is heat sealed
most heat seals are polyethylene based
other polymers used more critical applications
Aesthetic appearance
clarity
surface gloss
reflective metallics
21
Describing Packaging Laminate
Note:
Packaging laminate plies are always listed from the outside to the inside
22
Gravure Coating
23
Wet Bond Laminator
24
Dry Bond Laminating
25
Solventless Laminating
Solventless laminating uses catalyzed or or two-part reactive adhesives
26
Extrusion Laminating
Extrusion d ie
C h ill ro ll
Substrate A
Substrate B
S trip -o ff ro ll
P ressure ro ll
N ip ro ll
Extrudate Three p ly lam ina te
27
Hot Tack
The bond strength of the seal while still hot
Critical for most form-fill-seal machines
Determines how quickly product can be dropped into a pouch
28
Common Heat- Seal Materials
costbond quality
ionomer (e.g. Surlyn, seals through contaminants )
acid copolymer (good foil bond, chemical resistance)
metallocene polyethylene (low temp, fast seal)
LLDPE (good hot tack, tough, wide seal temp.)
PE/EVA (soft film, low seal temperature)
medium-density polyethylene (stiffer, better barrier)
cast polypropylene (stands higher temperatures)
low-density polyethylene
29
Sealing Mediums Compared
3000
2500
2000
1500
1000
500
120 125 130 135 140 150145 160 170 180
LDPE
Oct. LLDPE
m PE F orce g / inch
Tem pera ture (deg rees C )
Hot Tack Strength
30
Heat Sealing Parameters
Increasing Tem perature
Hea
t-S
eal S
tren
gth
H igh barpressure
M edium bar pressure
31
foil
polyethylene
poly(ethylene terephthalate)
foil
sealing medium
printed paper
sealing medium
Retort pouch Aseptic box
sealing medium
printed polypropylene
metallized polypropylene
Snack food bag
saran-coated nylon
sealing medium (Surlyn)
Luncheon meat tray
Example Laminations
32
printed polyethylene
polyethylene
Ethylene-vinyl alcohol
High oxygen barrier
polyethylenepoly(ethylene terephthalate)
sealing medium (vinyl)
overlacquer
Single-service lidding stock
printed foil
Example Laminations
(For barrier applicationsfoil to the inside)
surface print
paper
polyethylene
sealing medium
foil
Basic food pouch laminate
33
Laminateroll stock
Highbarrierinsert
Finished tube1
Injected molded tip
Laminated Collapsible Tube Construction
Formed body
Foil
Clear LDPE
paper
Sealing medium
Printed white PE
EAA
34
Vertical Form-Fill-Seal (VFFS)
U nw ind
P roduc t flow
D raw -dow n be lts
Long itud ina l sea ling jaw
C ross-sea ling and cu t-o ff
F o rm ing co lla r
CoF is critical!
35
VFFS Pouch Seals Compared
Fin seal Lap Seal
Seals inside surfaces
Uses more material
Don’t cover UPC!
Seals outside to inside
Both surfaces need sealing medium
Use less material
36
Horizontal Form-Fill-Seal (HFFS)
U nw ind
Tens ion contro l
F o rm ing p low
Top sea l
C u t-o ff
O pen pouch
F ille r #1F ille r #2
F ille r #3C lose pouch
S ide sea l
37
Common HFFS Pouch Styles
Conventional pouch has three-side seal
Can be made into various stand-up designs
Some stand-up pouches are pre-made in a separateoperation
Three-side sealed pouch
Gusseted designs
38
Multi-Lane Form-Fill-Seal
Vertica l hea t sea ls H orizon ta l hea t sea ls
P roduc t d ispensers
F our-s ided sea l pouches(separated )
39
Stand-Up Pouch Examples
40
Stand-Up Pouch Examples
41
Film Thickness Measurement
Inch Gauge Mil Micrometre
0.001inch = 100 gauge = 1 mil = 25 m
0.0005 inch = 50 gauge = 1/2 mil = 13 m
ISO metric notes:“Micron” is a depreciated term for micrometre
one inch = 25.4 millimetres and
0.001 inch = 25.4 micrometres
42
Early Universal Barriers
PVDC is original high universal barrier polymers
EVOH laminated between high moisture barrier
polymers can also provide good universal barrier
But not high enough barrier for critical applications
Metallizing also produces a high universal barrierBut aluminum metallized films are not transparent
43
Recent Advances in Achieving Barrier
Monolayer polymers
poly(ethylene naphthalate) ($)
liquid crystal polymer ($$$)
Multilayered constructions
PET/PA/PET
PET/EVOH/PET
PET/MXD6/PET/ MXD6/PET
44
Recent Advances in Achieving Barrier
Interior coatingsSiOx (glass) coating (Glaskin)AlOx aluminum oxide coatingcarbon coating (DLC and Actis)
Exterior coatings and interior laminatesepoxy-amine coating (Sealica and Bairocade)copolyester (Amosorb: interior layer)
Nanocompositesextremely fine mineral additions