Film Properties

Product protection by Films

FoodAroma

Moisture

Water vapour Light

Oxygen

0078d

Required properties of filmsmechanical strength: tear propagation resistance

puncture resistance

barrier properties: gas (O2,N2,CO2)aromawater vapor

heat resistance: boiling resistance (~100C)pasteurizationsterilization (~121C)microwaveablerefrigerateable

sealant: high seam stengthlow temperature sealablepeel

optics: transparentglossscratch resistanceUV-resistant

0082d

USA 1932 Polyamide - 6.6 ("Nylon") was developed and produced 1938 by Du Pont.Europe/Germany 1938 Polyamide -6 (Perlon) was developed and production from 1939. In packaging films Polyamide 6 is mostly being used.

Density =1,14 [Kg/dm] Melting point (FP) =220 C

incinerating with Oxygen present results into: CO2,H2O and N0x with calorific value of: 28,7 MJ/kg

Typical Properties: Low Gas-Barrier and hydrophilicFrom raw material (Granulate) to packaging film: Extrusion into an unoriented cast/flat-film, cooling, winding.Alternatives: Coextrusion or in-line-coating with polyolefin-sealing layers.After extrusion biaxial or monoaxial stretching possible.Alternatives: Coextrusion PA/EVOH/PA monoaxial in machine direction (MD).

Using of PA in packaging:Always as substrate-layer in composite-films, either oriented e.g. as top-film for flowpack, or unoriented for deep drawing application.

Summery of properties:High gas barrier (by using EVOH even higher), strong, firm and very tough, (see Nylon stockings)good optical transparency, good thermal resistance, good flex crack resistance at low temperatures,bad Water-vapour barrier.

POLYAMIDE

Developed 1936, 1939 Production by ICI (LDPE) starting 1952 ZIEGLER & NATTER Catalyst were developed to produce the various PE polymers (LLDPE, HDPE, MDPE)). The Metallocene Catalyst was developed in the mid 90s.

Type Density [Kg/dm] Melting Point [C]

LDPE 0,915 - 0,925 105 - 115LLDPE 0,920 - 0,935 125 - 135MDPE 0,925 - 0,940 115 - 125HDPE 0,940 - 0,965 125 - 135mPE 0,882 0,912 70 - 122

In addition there are variety of copolymers up to Ionomer and a multitude of Metallocene PEs

incinerating PE with Oxygen present results into: C02 und H20 with calorific value of: 43,4 MJ/kg

Typical properties: soft and low meltingFrom Raw material (Granulate) to packaging film: extrusion into an blown film, cast film or coating

Usage of PE in packagingMainly as mono film for bundle packs, palletising and packaging, without any specific gas barrier function,also PEs are used in sealing layers for composite films (multilayer packaging films).

Summery of properties:Good water vapour barrier, soft and firm, medium optical transparency, at low temperatures sealable (there for used as sealing layer, good flex crack resistance, impermeable for unpolar Gases (O2 , CO2 and N)

0083d

POLYETHYLEN

0052d

Standard LLDPE

- Olefin + Ziegler & Natter Catalyst = LLDPE

Metallocene PE

- Olefin + Metallocene Catalyst = mPE

Simplified production process of Polyethylene

0084e

In multilayer-films Ionomer are predominantly used as sealing layers.Ionomer are thermoplastics whose molecular chains are cross linked via ionic bond.All Ionomer available on the market contain either

zinc or sodium Ionomer

Exceptional features:

High impact resistance, even at low temperatures

High puncture and abrasion resistance

High melt elasticity

Excellent thermoforming performance

Bonds well with POLYAMIDE (co-extrusion)

Low sealing temperature, high seal strength, excellent hot tack

Resistant to oil, fats, greases and solvents, therefore less sensitive to contamination of the sealing areas, for instance with fat or meat juice during fresh meat packaging

Excellent clarity and high gloss, therefore superb pack appearance

Ionomer(Surlyn, from DuPont)

Sketch of a composite film

SubstrateAdhesive

Sealing layer

Barrier

0080e

Oxygen and water vapour barrier

Required thickness for oxygen barrier of 10 ccm / m d bar

0,4 m = 0,0004 mm EVOH90 m = 0,0900 mm PA unoriented

7500 m = 7,5000 mm PP unoriented20000 m = 20,000 mm LDPE20000 m = 20,000 mm HDPE

Required thickness for water vapourbarrier of 1 g / m d

40 m = 0,040 mm HDPE70 m = 0,070 mm PP unoriented

100 m = 0,100 mm LDPE200 m = 0,200 mm EVOH900 m = 0,900 mm PA unoriented

R e q ire d th ic k n e s fo r o x y g e n b a rrie r o f 1 0 c c m /s q m /d a y /b a r

0 2 0 0 4 0 0 6 0 0 8 0 0 1 0 0 0

E V O H

P A

P P

L D P E

H D P E

th ic k n e ss in m

R eqired th ic k nes fo r ox y gen barrier o f 10 c c m /s qm /day /bar

1 10 100 1000 10000 100000

E V O H

P A

P P

LD P E

HD P E

th ickn e ss in m

0081e

Light proofOxygen proofWater vapourimpermeable

Transparent with

High oxygen barrierWith high water vapour barrier

Transparentwith

medium oxygen barrierWith high water vapour barrier

Transparentwith

low oxygen barrierWith high water vapour barrier

Mono-FilmsBOPPPPPEEVAIonomer

Laminates/CompositesBOPP with PVDC-Lack ,PEoriented PA with PEPET oriented with PVDC-Lack, PEunoriented, coextr.PA/PE-multi-layer film

Laminates/Compositesunoriented PA/EVOH/PA with PE or Ioriented PA/EVOH/PA with PEoriented, lack.PVOH with PEoriented metallised PET,PA with PE or I

Laminates/Compositesoriented PP with Al and PE, Ioriented PA with Al and PE, Ioriented P with Al and PE

Pyramid of barrier - properties

0324e

Comparison of plastic films in terms of theirapplication-related properties

thermoformable non-oriented filmsProperties PP PA 6 PET EVOH LLDPE LDPEOptical properties (clarity, gloss) 0 0 + + 0 -Tensile strength + ++ + 0 0 -Impact penetration resistance + ++ - 0 0 0Toughness + ++ - 0 0 -Stiffness + + ++ + 0 --Thermal stability 0 + ++ + - -Oxygen barrier -- + 0 ++ -- --Aroma barrier 0 + ++ + - --Water vapour barrier ++ - 0 -- + +Chemical resistance ++ + + + + +Sealability + -- -- -- + +Processing performance (metallization, printing laminating) + ++ ++ - + +

Films

Size of mould:

Location of measurement points

B T

1

2

3 4

5 6

L = = =

180 115

90 mm mm mm

0

20

40

60

80

100

120

140

160

180

200

1 2 3 4 5 6

Mepunkte

D

i

c

k

e

i

n

m

Multi MD 200

Multi Plus 155

Comparison of Combitherm Multi Plus and Combitherm MD / TC / SC

0327d

Comparison of Puncture Resistance

Combitherm Multi Plus 250

Distance

Force

16 mm

55 N

Combitherm Multi I Plus 250

Distance

14 mm

Force

67 N

tough

Distance

16 mm

Force

75 N

Combitherm TCI 250

toughesttougher

Properties

0325e

Comparison of plastic films in terms of theirapplication-related properties

Oriented filmsProperties BOPP PAB/PAL OPETOptical properties (clarity, gloss) + + ++Tensile strength + ++ ++Impact penetration resistance + ++ +Toughness + ++ 0Stiffness + + ++Thermal stability 0 + ++Oxygen barrier -- + 0Aroma barrier - + ++Water vapour barrier ++ - 0Chemical resistance + + ++Sealability +* -- --Processing performance (metallization, printing laminating) ++ ++ ++

Ra

Films

Barrier properties of raw plastic materials

1

10

100

1.000

1 10 100 1.000 10.000

O2 [ml/(m*d*bar)] 23C/ 75% r.h.

H

2

O

[

g

/

(

m

*

d

)

]

4

0

C

/

9

0

%

r

.

h

.

EVOH

PVDC

PA6

PP

OPP

OPAPC

PET LDPE

PS

OPET

HDPE

Foliendicke 25 m

Barrier properties of raw plastic materials

Barrier

0206e

UV light transmission spectra of Combitherm Multi Plus and PA/PE film struktures

Polyamide mod.

tie layer

Polyamide mod.tie layer

Polyethylene

Polyethylene(EVA)

Polyamidetie layerPolyamidetie layer

Polyethylene

Polyethylene(EVA)

CombithermMulti MD

Comparison of Combitherm Multi Plus and MD

PolyethylenePolyethyleneTie LayerPolyamidePolyamideTie LayerPolyethylenePolyethylene / EVAPolyethylene / EVAPolyethyleneTie LayerPolyamidePolyamide

Ionomer

Polyethylene

Polyethylene

CombithermMulti Plus

Combitherm TC

Combitherm TC / I

0376de

Ionomer

Ionomer

Ionomer

Polyamide

Polyamide

Tie Layer

Polyethylene

Polyethylene / EVA

Polyethylene / EVA

Polyethylene

Tie Layer

Polyamide

Polyamide

Ionomer

Ionomer

Ionomer

Polyethylene

Tie Layer

Polyamide

Tie Layer

Polyethylene

EVA

TC 140TC 140

TC I 250 TC I 250

C`therm MD 170C`therm MP 180

C`therm TC 170SuperClear 10

90 mm

100 mm

120 mm

Comparison of thermoforming capabilitiesof Combitherm Multi Plus, MD, TC and SC

Rule-of-thumb for maximum draw depthwithout plug-assist

Properties

R x 100

6,1 + ( 1,5 L/T + 0,93 B/T )

D [m] = Required film thicknessR [m] = Desired remaining thickness (recoummended 25-30 m)L [mm] = Length of mouldB [mm] = Width of mouldT [mm] = Depth of mould

Example: R=30m, L=200mm, B=100mm, T=80mm; =>>D= 272 m

D =

Rule-of-thumb to calculate remaning thickness on corners of package

Product protection by FilmsRequired properties of filmsPOLYAMIDEPOLYETHYLENSimplified production process of PolyethyleneIonomer(Surlyn, from DuPont)Sketch of a composite filmOxygen and water vapour barrierPyramid of barrier - propertiesComparison of plastic films in terms of their application-related propertiesComparison of Combitherm Multi Plus and Combitherm MD / TC / SCComparison of Puncture ResistanceComparison of plastic films in terms of their application-related propertiesUV light transmission spectra of Combitherm Multi Plus and PA/PE film strukturesComparison of Combitherm Multi Plus and MDCombitherm TC / IRule-of-thumb for maximum draw depth without plug-assistRule-of-thumb to calculate remaning thickness on corners of package