Non-Migrating Polymeric Slip Additive In LDPE Films

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Cyclic-Olefinic Copolymers as Non-Migrating Polymeric Slip Additives

in LDPE Cast Films

Author: David R. ConstantSpeaker: Randy D. Jester

TAPPI/ANTEC Exchange 2002

Abstract

Cyclic-Olefinic Copolymers (COC) use is growing in flexible packaging films

Attributes include easy processing, stiffness, heat resistance, moisture barrier and clarity

Can be used as a non-migratory slip and antiblock additive in polyolefins, depending on:

the matrix LDPE density

type and blend level of COC

process conditions

Overview

Blends of COC in LDPE can reduce C.O.F. to 0.2 - 0.4

Low C.O.F. can be achieved with as little as 5 -10%COC

Key factors contributing to low C.O.F. include:

Tg of the COC

“Low” process melt temperature

BackgroundConventional slip additives are an integral part of the packaging films industry

Conventional slip additives function by “blooming” to film surfaces, occasionally causing product consistency “issues”

Non-migrating slip additives have seen limited success for many years

COC’s provide an alternative, organic,ethylene based, polymeric choice

COCs are produced by combining ethylene, norbornene

and metallocene catalysts

C H 2C H 2

Tg range: 70 - 170CRefractive index: ~ 1.53

ExperimentalMaterials: MI Density Tg°C

Dow 4012 LDPE 12 0.918 -127

Equistar NA 952 2 0.918 -127

Equistar NA 324 3 0.931 -127

Topas 8007 COC 1.8 1.02 80 (low)

Topas 5013 COC < 1.0 1.02 136 (high)

Extrusion:

25 mm Killion (DS), DSB I barrier type screw, 30: 1 L/D, Maddock Mixing head

T range: 160 - 260°C, Cast rolls: 35°C,film: 51 microns

Testing Equipment:

for C.O.F. MTS 8016 Tensile testing machine, 200 g sled, 150 mm/min, 23°C, 50% r.h. (ASTM D 1894)

Static and Dynamic Measurements

Microscopy Optical (phase contrast, 625X), Scanning Electron (SEM, 2400X), and Atomic Force (AFM, 700X)

DMA TA Instruments Dynamic Mechanical Analyzer (DMA), model 2980, tension mode on MD film, 3°C/min. temperature sweeps, at 10HZ

Experimental (cont.)

C.O.F. Baseline

Typical C.O.F. Interpretations for films:High Slip 0.10 - 0.20Medium Slip 0.21 - 0.40Low Slip 0.41 - 0.70Neglible Slip > 0.70

Fig. 1a C.O.F vs. Tm for 10% 80 Tg and 10% 136 Tg COCs in 12 MI LDPE(1st Column = Static 2nd Column = Dynamic)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

C.O.F.

Note: C.O.F. Values ~ same @ 5% COC

160C 180C 200C 240C 250C 260C

80°C Tg136°C Tg

Process Temperature °C

0

10

20

30

40

50

60

Fig. 1b % Haze vs. Tmelt for 10 & 5% COC in 12 MI LDPE1st Column = 10 % COC 2nd Column = 5 % COC

160C 180C 200C 240C 250C 260C

80°C Tg136°C Tg

Process Temperature °C

% HAZE

-128.34°C-3.57°C

77.39°C

26.33°C

-21.75°C

73.20°C

25.36°C

103.62°C

0.1

Tan

Del

ta

0.1

1

10

100

1000

10000

Loss

Mod

ulus

(MP

a)

0.1

1

10

100

1000

10000

Sto

rage

Mod

ulus

(MP

a)

-130 -80 -30 20 70 120

Temperature (°C)

Sample: T0839; 90%LDPE4012+10%8007Size: 15.3730 x 10.0000 x 0.0500 mmMethod: Topas-Blend-TempSweComment: 90%LDPE Dow4012+10%Topas8007;3°C/min,1Hz,60microns

DMAFile: C:...\T0839A_DMA.001Operator: Dr. A. Romo-UribeRun Date: 18-Oct-01 11:00

Universal V2.5H TA Instruments

Fig. 2 DMA Data: LDPE, 80°C Tg COC and LDPE + 10% 80°C Tg COC( γ, β, α and α’ Transitions)

36.39°C

1.39°C

102.96°C

-20.42°C

-127.03°C

39.12°C

-127.36°C

0.1

Tan

Del

ta

0.1

1

10

100

1000

10000

Loss

Mod

ulus

(MP

a)

0.1

1

10

100

1000

10000

Sto

rage

Mod

ulus

(MP

a)

-130 -80 -30 20 70 120

Temperature (°C)

Sample: T0844-Dow4012 LDPE film, 2 milSize: 16.8980 x 10.0000 x 0.0520 mmMethod: Topas-Blend-TempSweComment: Dow 4012 LDPE (2 mil); 3°C/min, 10Hz, 50microns



92.39°C

26.23°C

-125.72°C

-125.72°C

26.96°C

78.03°C

0.1

1

Tan

Del

ta

1

10

100

1000

10000

Loss

Mod

ulus

(MP

a)

1

10

100

1000

10000

Sto

rage

Mod

ulus

(MP

a)

-130 -80 -30 20 70 120

Temperature (°C)

Sample: T746;Topas COC 8007 2.8mil filmSize: 21.6210 x 12.0000 x 0.1200 mmMethod: Topas-Blend-TempSweComment: Topas 8007;TSwe@3°C/min,-130 to 100°C;10 Hz

DMAFile: F:...\T0746_DMA.001Operator: Dr. A. Romo-UribeRun Date: 30-Mar-01 17:05


LDPELDPE + COC

COC

92°C

77°C

Note: α transitions in tan δ curve show “some” degree of miscibility.

Fig.3 Phase Contrast Optical Microscopy: 80% 12 MI LDPE + 20% 80°C Tg COC,

51 µm cross section, 625X

200C

160C

180C

Fig.4 SEM, 80% 12 MI LDPE + 20% 80°C Tg COC, 51 µm, cross section, 2400X

160C 180C

200C

Fig. 5 AFM : 80% 12 MI LDPE + 20% 80°C Tg COC, 80 µm measured surface area, ( 700X )

160C 180C

200C

High Surface Roughness = Low C.O.F.

3.5

1.1

5.2

3.8

1.4

0.8

2.5

1.3

0.0

1.0

2.0

3.0

4.0

5.0

6.0

COF Value .

0.9310.918

Fig. 6 Effect of LDPE density on C.O.F.( 2-3 MI LDPE / 80°C COC Blends )

1st Column = Static 2nd Column = DynamicTm = 260°C

COC Blend Level ( % )

10% 20%20% 10%

Fig. 7 Effect of 80°C Tg COC Blend level on COF in LDPE1st Column = Static 2nd Column = Dynamic

0.74

0.42

0.290.20

0.58

0.440.34

7.5 7.5

0.25

0

0.2

0.4

0.6

0.8

1

1.2

1.4

COF value

10 % 20 % 40 % 60 % 80 %

Tm = 240°CLDPE δ = 0.918LDPE MI = 2

COC Blend Level ( % )

Conclusions and Recommendations

COC can reduce C.O.F. to commercially acceptable levels of 0.2 - 0.4 in cast LDPE filmsTg and Processing Conditions are Critical

Tm for blends with 80°C Tg COC: 160 - 180C ( ~320 - 350F)Tm for blends with 136°C Tg COC: 240C ( ~465F)

Blend Level and Density of the LDPE matrix are FactorsClarity

Haze expectation: up to 50%Contact Clarity: Good

Other Expectations:Printability, like LLDPESealing, dependent on Tg and level of the COC used

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AcknowledgementsI would like to thank the following people for their

contributions to this paper:Dr. Rong Chen

Dr. Angel Romo-Uribe

Darrin Behrens

Robert Roschen

Rick Vliet

Betsy Kelly

Kathy Fitzgibbon

Betty Fernekess

Back-ups

Fig. 8 C.O.F. of 90%LLDPE / 10% 136°C COC in Cast Film vs. Process Temperature

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

LLD/COC blend & Process Temperature

C.O.F.

static dynamic

160°C 180°C 200°C

LLDPE: 1 MI, .920

Fig. 9 %Haze of 90%LLDPE / 10% 136°C COC in Cast Film vs. Process Temperature

0

10

20

30

40

50

60

70

80

90

LLD/COC blend & Process Temperature

% Haze

160°C 180°C 200°C

LLDPE: 1 MI, .920

Fig. 10 136°C Tg COC

79.17°C

27.33°C

164.00°C

-127.06°C

150.08°C

0.1

1

Tan

Del

ta

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1000

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Loss

Mod

ulus

(MP

a)

0.1

1

10

100

1000

10000

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rage

Mod

ulus

(MP

a)

-140 -100 -60 -20 20 60 100 140 180

Temperature (°C)

Sample: 38970-03-6;Topas5013,-140-200°CSize: 16.4290 x 12.2000 x 0.5700 mmMethod: Topas5013-TempSweComment: 100% Topas 5013.50rpm;3°C/min,1Hz,10microns



Fig 11 12 MI LDPE + 10% 136°C Tg COC

tan (delta)

10HzE'

E"

77.48°C

-113.77°C

-5.96°C

11.60°C

49.94°C

-14.09°C

50.00°C

0.1

1

Tan

Del

ta

0.1

1

10

100

1000

10000

Loss

Mod

ulus

(MP

a)

0.1

1

10

100

1000

10000

Sto

rage

Mod

ulus

(MP

a)

-150 -100 -50 0 50 100 150

Temperature (°C)

Sample: T0976C Topas 501-K11-2Size: 14.6500 x 13.2000 x 0.1300 mmMethod: Topas-Blend-TempSweComment: 90% LDPE + 10% Topas 5013 film

DMAFile: D:...\T0976C_DMA_Film.001Operator: T. DeStioRun Date: 18-Apr-02 15:18


Non-Migrating Polymeric Slip Additive In LDPE Films

Technology

Transcript of Non-Migrating Polymeric Slip Additive In LDPE Films