Polypropylene - Building Blocks for Blown Film · PDF filePolypropylene - Building Blocks for Blown Film Applications ... tight project timelines, ... The bubble blow up ratio (BUR)

Polypropylene - Building Blocks for Blown Film Applications Spencer Hirata and Ganesh Nagarajan Basell USA Inc. ABSTRACT: A common question posed by many application and development engineers is “What type of film should I propose for my customer’s application?” When formulating a plan to answer this question, which often includes making a list of potential materials and structures, some materials may be overlooked or dismissed as potential candidates. Often this is the case for polypropylene when structures for blown film applications are developed. This is unfortunate because some interesting features and opportunities may be missed. Rather than focusing on the manufacturing techniques, structure or inherent properties of polypropylene this discussion provides examples that compare the properties of several blown polypropylene films. The experimental examples include the following: composition effects of two component blends, comparison of blends to co-extrusions, comparison of polypropylene and polyethylene co-extruded films, and an application example – making a clear, tough film. The goal of this paper is to provide sufficient incentive for applications and development engineers to reconsider PP for blown film applications. INTRODUCTION: A common question asked by film applications and development engineers is, “What type of film should I propose for my customer’s application?” While this seems to be a simple question, it is often complicated by the seemingly endless choices of materials and ways to combine them. Maybe a better way to phrase the question is, “What types of polymers should I consider and how should I put them together?” Under the pressure of limited resources and tight project timelines, an engineer will often not have time to consider all potential solutions and will begin with materials with which they are familiar. While this approach is acceptable, one may miss opportunities for differentiated solutions. For most people the terms blown film and polyethylene (PE) are almost synonymous. As a result, materials such as polypropylene (PP), more commonly associated with oriented and cast film applications, are often overlooked or dismissed from consideration. However, as the range of applications broadens and film property requirements become more differentiated, PE materials may not always provide the right balance of characteristics required. For these situations, PP materials may help provide unique solutions. When considering unfamiliar materials for their film applications, many engineers indicate that they would prefer comparative data based on “real” films. To demonstrate the utility of PP in blown film structures, a compilation of experiments completed on a small commercial sized line has been put together. Topics included are: the effect of blending two components in a monolayer film structure, comparison of two component blends to two component co-extruded film structures, comparison of PP and PE based co-extruded structures, and an example for making a clear, tough PP film. Experiment #1: Effect of Blending on Blown Film Properties When a single polymer does not provide the properties required for a blown film application, one often considers combining two or more polymers together. The objective is to maintain the best qualities of each polymer while minimizing less desirable properties. One of the most common methods is by making a pellet-pellet blend. For this example, two PP materials were considered for blend modification. One is a 1.2 MFR homopolymer polypropylene (HPP) and the other is a 0.45 MFR impact polypropylene copolymer (i-PPC). The materials selected as the second blend components are two highly modified impact PP copolymers, commonly referred to as thermoplastic polyolefins (TPOs). Although TPOs are often used alone, they are also very useful as blend

modifiers. A list of the materials used in this experiment is provided in Table 1-1 along with some standard material properties. Table 1-1: List of PP materials for blend experiment Material ID Description MFR 2.16 kg / 230 °C

(g/10 min) Flexural Modulus

(MPa) HPP Homopolymer PP 1.2 1420 i-PPC Impact PP copolymer 0.45 1200 TPO-A Thermoplastic olefin 0.65 400 TPO-B Thermoplastic olefin 0.6 80 A series of two component blends were made by tumble blending the pellets together at different ratios ranging from 0% to 100%. The blend combinations are listed in Table 1-2. Table 1-2: List of Blend Combinations Materials Modified with TPO-A Materials Modified with TPO-B HPP + TPO-A HPP + TPO-B i-PPC + TPO-A i-PPC + TPO-B Each of the blends were extruded and then blown into 0.001 inch (25.4 m) monolayer films. The bubble blow up ratio (BUR) used was 2:1. The process set up characteristics for the blown film line is provided in Table 1-3. Table 1-3: Process Set Up for Experiment #1 Extruder Name B Nominal Extruder Diameter 3.5 inch Screw L/D Ratio 30:1 Number of Heating Zones 5 Screw Type Single, Barrier Mixing Section Type Maddock Die Size 8 inch (203.2 mm) Die Lip Gap 0.080 inch (2.032 mm) Cooling Dual Lip Air Ring with Chilled Air Physical testing was completed for each of the film samples and summarized in the graphs, Figures 1-1 through 1-22. These tests included Elmendorf tear resistance, 1% secant modulus, tensile strength, falling dart impact, puncture resistance, haze, 45° gloss and heat resistance. Table A-2 in the Appendix provides a list of the test method references. Heat resistance is an internal test method used to determine the temperature in which the films would stick to each other. The graphs are presented in pairs, with properties of the TPO-A modified blends on the left side (odd numbered figures) and the TPO-B modified blends on the right side (even numbered figures). An overall summary of the comparisons is provided in table 1-4.

Figure 1-1: Figure 1-2: MD Elmendorf Tear Resistance

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Table 1-4: Summary - Effect of blending TPOs into HPP and i-PPC HPP i-PPC TPO-A TPO-B TPO-A TPO-B 1% Secant Modulus MD TD Tensile Strength MD — — TD — — — — Heat Resistance — Elmendorf Tear Resistance MD — — — — TD — — — Falling Dart Impact — Protrusion Puncture Resistance — — Haze — — — — 45° Gloss — — — — — no significant effect

small decrease , small increase large decrease, large increase

The most noticeable influence of blending the TPOs into the HPP and i-PPC materials was the reduction in the 1% secant modulus as the TPO weight percentage of the blend was increased. Although the TPO-A also affected the dart impact and heat resistance of the i-PPC, TPO-B exhibited a much greater impact on both blend combinations, resulting in a reduction of the films’ tensile strength and heat resistance while increasing the falling dart impact strength and protrusion puncture resistance. Also noticed was that the bubble stability of both the HPP and i-PPC materials improved as the TPO level increased. Experiment #2: Comparison of Blending to Co-extrusion in Blown Film Structures Another method used to combine materials is by creating multilayer structures. For blown films, the most common method is by co-extruding the different materials through a single die. In a simple 3 layer structure, this technique allows the creation of films with differentiated characteristics: a core layer material with a different skin layer material (ABA) or a core layer material with two different skin layer materials (ABC). So how do the properties compare to their pellet blend equivalents? In this experiment a series of two component structures were produced. One set of films were monolayer structures made from pellet-pellet blends while the other set were 3 layer, ABA co-extruded film structures. To keep the weight percentage of the co-extruded samples the same as their pellet blend counterparts (60% / 40%) the layer ratios were set at 30% - 40% - 30%. An example of the two film structures is provided in Figures 2-1 and 2-2 shown below.

Figure 2-1: Monolayer Film of Blend Figure 2-2: ABA Co-extrusion

30% i-PPC 60% i-PPC + 40% second component vs. 40% second component

30% i-PPC The primary material for this experiment was the same i-PPC used in experiment #1. The second component for each structure was selected from a set of materials which included 3 TPOs (each with a different flexural modulus), a linear low density polyethylene (LLDPE), a metallocene catalyzed linear low density polyethylene (mLLDPE), and a polyolefin elastomer (POE). A list of the materials is provided in tables 2-1 and 2-2. Table 2-1: Polyethylene materials used in blend vs. co-extrusion experiment Material ID Description MFR 2.16 kg / 190 °C

(g/10 min) Density (g/cc)

LLDPE LLDPE 1.0 0.918 mLLDPE mLLDPE 1.0 0.918 POE polyolefin elastomer 0.5 0.863 Table 2-2: Polypropylene materials used in blend vs. co-extrusion experiment Material ID Description MFR 2.16 kg / 230 °C


(MPa) TPO-A Thermoplastic olefin 0.65 400 TPO-B Thermoplastic olefin 0.6 80 TPO-C Thermoplastic olefin 0.6 20 The process set up characteristics for the blown film line is provided in Table 2-3. All films had a nominal thickness of 0.00354 inches (90 m) and were made with a bubble blow up ratio of 2:1.

Table 2-3: Blown Film Line Set Up Extruder Name A B C Nominal Extruder Diameter 60 mm 3.5 in 2.5 in Screw L/D Ratio 24:1 30:1 24:1 Number of Heating Zones 3 5 4 Layer Position in Co-extrusion Outer Core Inner Screw Type Single, Barrier Single, Barrier Single, Barrier Mixing Section Type Maddock Maddock Maddock Special Features Grooved Feed

Section

Die Size 11 inch (279.4 mm) Die Lip Gap 0.060 inch (1.524 mm) Cooling Dual Lip Air Ring with Chilled Air All the film structures and blends processed without difficulty. The physical properties of each film were tested and the data presented in graphs, Figures 2-3 through 2-12. This included Elmendorf tear resistance, 1% secant modulus, tensile strength, protrusion puncture resistance, falling dart impact, haze, and 45° gloss. Each graph shows the data for the blended monolayer structures as compared to the corresponding ABA co-extruded structures. Figure 2-3: Figure 2-4:


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For the purposes of this discussion, the focus is only the difference between the blend and co-extruded pairs, specifically which one provides the better performance. For all the properties listed except for haze, higher values are considered to be better. A summary of the observations is provided in Table 2-4. The numbers in the table represent the number of samples (out of 6) that favor either the blended monolayer or the ABA co-extruded structure. A check mark next to the values indicates the structure that showed an overall advantage.

Table 2-4: Summary - Comparisons of i-PPC blends to i-PPC co-extrusions Property No. of Samples Exhibiting Advantage Better i-PPC Blend i-PPC Co-extrusion Elmendorf Tear Resistance MD 2 4 TD 6 1% Secant Modulus MD 6 TD 5 Tensile Strength MD 3 3 TD 3 3 Falling Dart Impact 3 3 Protrusion Puncture Resistance 6 45° Gloss 5 1 Haze 1 5

- Higher value is considered to be better - Lower value is considered to be worse

6 - The number of samples (out of 6) that are considered to be better - advantage

The results show that some properties favor one structure over the other. For the co-extruded film structures, an advantage was seen for 1% secant modulus, haze and TD tear resistance while the monolayer films seem to provide better protrusion puncture resistance and 45° gloss. For other properties such as MD & TD tensile strength, falling dart impact, and MD tear resistance the mixed results indicate that the outcome is highly dependent on characteristics of the second component. Experiment #3: Comparison of Polypropylene and Polyethylene Co-extruded Blown Films After reviewing experiment #2 a commonly asked question is “How would LLDPE based co-extruded structures compare to those based on i-PPC?” To answer this, another set of structures were produced replacing the i-PPC with the LLDPE. The LLDPE films were made on the same blown film line using the same conditions. The film thickness remained at 0.00354 inch (90 m) and the BUR at 2:1. An example of the film structures being compared is provided in Figures 3-1 and 3-2.

Figure 3-1: i-PPC ABA Co-ex Figure 3-2: LLDPE ABA Co-ex

30% i-PPC 30% LLDPE 40% second component vs. 40% second component 30% i-PPC 30% LLDPE

The film properties tested included: Elmendorf tear resistance, 1% secant modulus, tensile strength, puncture resistance, falling dart impact, haze, and 45° gloss. The data is provided in the graphs, Figures 3-3 through 3-12. The first data set in each of the graphs compare the structures i-PPC / LLDPE / i-PPC and LLDPE / i-PPC / LLDPE.

Figure 3-3: Figure 3-4: MD Elmendorf Tear Resistance

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Table 3-1: Summary comparisons of i-PPC to i-PPC co-extrusions Property No. of Samples Exhibiting Advantage Better i-PPC Co-ex LLDPE Co-ex Elmendorf Tear Resistance MD 1 5 TD 3 2 1% Secant Modulus MD 6 TD 6 Tensile Strength MD 6 TD 4 2 Falling Dart Impact 1 5 Protrusion Puncture Resistance 5 1 45° Gloss 6 Haze 6

- Higher value is considered to be better - Lower value is considered to be worse

6 - The number of samples (out of 6) that are considered to be better - advantage

The LLDPE based co-extruded structures provide advantages in MD tear resistance, haze, 45° gloss and dart impact resistance. The i-PPC based co-extruded structures provide advantages in MD & TD secant modulus and MD tensile strength as well as a slight advantage in puncture resistance. Experiment #4: Making a Clear, Tough Blown Polypropylene Film As seen in the earlier examples the optical properties of blown films made from standard PP materials are not very good, exhibiting high haze and low gloss. This would seem to exclude PP in applications requiring transparency and sparkle. Experiments were completed to address these deficiencies by incorporating a clarifying additive into the PP. An unmodified PP film and a PE film were produced as comparative control samples. The PE film structure selected is typically targeted for use in stand up pouch applications. The key properties reported for this application are low haze, high gloss, high modulus, high dart impact, high puncture resistance, high Elmendorf tear resistance, and high heat seal strength. Several types of PP were used in this example: an HPP (the same used in experiment #2), several random copolymers (r-PPC) and the TPO-B used in experiments #1, #2 and #3. The r-PPCs and TPO-B were included to improve the film’s tear resistance, dart impact and protrusion puncture resistance. The clarifying additive was added to each layer of the test samples to obtain the maximum effect. The materials used in this experiment are listed in Tables 4-1 and 4-2. Table 4-3 contains a listing of the film structures produced. The clarified film samples are identified as Sample #1, Sample #2 and Sample #3. Table 4-1: Polyethylene materials used in Clear PP Film Experiment #4 Material ID Description MFR 2.16 kg / 190 °C

(g/10 min) Density (g/cc)

mMDPE mMDPE 0.8 0.933 HDPE HDPE 1.2 0.961

Table 4-2: Polypropylene materials used in Clear PP Film Experiment #4 Material ID Description MFR 2.16 kg / 230 °C


(MPa) HPP Homopolymer PP 1.2 1420 r-PPC-A Clarified random copolymer 2.0 1000 r-PPC-B Random copolymer 5.5 650 r-PPC-C Clarified random copolymer 6.0 na TPO-B Thermoplastic olefin 0.6 80 Table 4-3: Experimental Film Structures in Clear PP Film Experiment #4 Layer PE Control PP Control Sample #1 Sample #2 Sample #3 Skin mMDPE r-PPC-B r-PPC-C r-PPC-C r-PPC-C Core HDPE HPP 70% HPP +

30% r-PPC-C r-PPC-A 70% r-PPC-A +

30% TPO-B

Skin mMDPE r-PPC-B r-PPC-C r-PPC-C r-PPC-C The 0.003 inch (76.2 m) thick co-extruded films were produced on the 3 layer blown co-extrusion film line similar to that described in experiment #2 and #3. A list of the process set up conditions is provided in Table 4-4. The layer ratios of the ABA co-extruded film structure were set at 10% - 80% - 10%. The bubble BUR was set at 1.7:1. Table 4-4: Blown Film Line Set Up Extruder Name A B C Nominal Extruder Diameter 60 mm 3.5 in 2.5 in Screw L/D Ratio 24:1 30:1 24:1 Number of Heating Zones 3 5 4 Layer Position in Co-extrusion Outer Core Inner Screw Type Single, Barrier Single, Barrier Single, Barrier Mixing Section Type Maddock Maddock Maddock Special Features Grooved Feed

Section

Die Size 11 inch (279.4 mm) Die Lip Gap 0.080 inch (2.032 mm) Cooling Dual Lip Air Ring with Chilled Air The films were tested and the data summarized in Figures 4-1 through 4-8. Film physical properties tested included: Elmendorf tear resistance, 1% secant modulus, tensile strength, protrusion puncture resistance, falling dart impact, % haze, 45° gloss and heat seal strength.


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The clarifying additive performed as hoped, resulting in very low haze and high gloss for the experimental samples. Even for a fairly thick film, 0.003 inches thick (76.2 m), the haze values compare favorably to blown clarity films or films made on a cast or water quench processes. The experimental films modified with the r-PPC and TPO exhibited lower modulus and tensile strength while providing greater dart impact and protrusion puncture resistance with a modest improvement in Elmendorf tear resistance. The sample with properties most comparable to the PE control was sample #3 that had the TPO modified core layer. This is most interesting since the addition of a TPO would normally result in a very hazy film. In this case, the combination of the clarifying additive and encapsulation of the TPO in the core layer has provided for a good balance of optics, toughness and process bubble stability. In addition to good optics, the use of a PP terpolymer as the skin layer also provides for strong heat seals. The seal initiation temperatures for the materials were estimated to be ~121°C for the PP control film, ~126°C for the Clarity film, and ~143°C for the PE film. CONCLUSIONS: The experiments demonstrate that PP materials can be used to produce a variety of blown film structures. The properties of these films can be modified by combining materials in either blends or co-extruded film structures. In the simple two component systems described, there does appear to be a trade off between properties such as stiffness (modulus) and toughness (tear resistance, dart impact and puncture resistance). The addition of a TPO or PE into the film structure also improved the process bubble stability. As shown in the last example, through careful material selection and combining the techniques described, it is possible to create films with very interesting properties - in this case, an uncommonly clear, tough PP film. In conclusion, though often overlooked, it would be wise to reconsider PP materials as essential building blocks for blown film applications. ACKNOWLEDGEMENTS: Special thanks and acknowledgement to Bill Brown, Andy Gillan, Bill Snyder and Tracey Meder for their considerable efforts in preparing the materials, producing the films and completing the lab film testing.

DISCLAIMER: All technical assistance and advice is furnished by Basell without compensation. Basell assumes no obligation or liability with respect to such advice and assistance and disclaims any and all warranties with respect to such advice and assistance. APPENDIX: Table A-1: Film Test Characteristics

Test Method Elmendorf Tear Resistance ASTM D 1922 1% Secant Modulus ASTM D 882 Tensile Strength ASTM D 882 Protrusion Puncture Resistance ASTM D 5748 Falling Dart Impact ASTM D 1709 Haze ASTM D 1003 45° Gloss ASTM D 2457 Heat Resistance Internal Method Heat Seal Strength Internal Method

2007 PLACE Conference

September 16-20

St Louis, MO

Polypropylene Polypropylene –– Building Blocks for Building Blocks for Blown Film ApplicationsBlown Film Applications

Presented by:Spencer HirataTechnical Service & Applications DevelopmentBasell USA Inc.

Types of Polypropylene (PP)

• Homopolymer HPP

• Random copolymer r-PPC

• Impact copolymer i-PPC

• Thermoplastic olefin TPO

PP Material Characteristics

• Stiffness

• Heat resistance

• i-PPCs and TPOs provide toughness and improved bubble stability

Potential Use As Building Block

• Alone

• Blends

• Co-extrusions

Experiments – Blown Film Properties

• Effect of blending

• Blending vs co-extrusion

• LLDPE vs i-PPC in co-extruded structures

• Application example

Experiment #1: Experiment #1: Effect of BlendingEffect of Blending

Modification of HPP and i-PPC

• Blended with TPOs

• Monolayer film thickness 25.4 µm

800.6TPO-B

4000.65TPO-A

12000.45i-PPC

14201.2HPP

Flex Mod (MPa)MFR (g/10 min)Material

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• Extruder: 3.5 inch

• Die: 8 inch diameter0.080 inch gap

• Air ring: dual lip with chilled air

• BUR: 2 : 1


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Tear

Res

ista

nce

(g)


Summary

————MD Tear Resistance

—/ —Haze

—Heat Resistance

——Protrusion Puncture

—Falling Dart Impact


TPO-BTPO-ATPO-BTPO-A

i-PPC BlendHPP Blend

Experiment #1 Conclusions

• Blending affects some film properties

• TPO-B exhibits greater influence on film properties as compared to TPO-B

• Observation - increasing TPO level improved bubble stability

Experiment #2:Experiment #2:Blending vs CoBlending vs Co--extrusionextrusion

Comparison of 2-Component Systems

• Monolayer blend vs ABA co-extrusion

– i-PPC combined with 2nd component (2nd)

– TPO or PE

• Film thickness 90 µm

ii--PPCPPC

ii--PPCPPC22ndnd60% i60% i--PPC + PPC +

40% 240% 2ndnd

} 30%} 40%} 30%

vs

2nd Component Materials: PP

200.6TPO-C

800.6TPO-B

4000.65TPO-A


2nd Component Materials: PE

0.8630.5POE

0.9181.0mLLDPE

0.9181.0LLDPE

Density (g/cc)MIE (g/10 min)Material

Equipment Set Up

• Extruders: 3.5 inch2.5 inch60 mm



• BUR: 2 : 1


0

200

400

600

800

1000

LLDPE mLLDPE POE TPO-A TPO-B TPO-C2nd Component

Mod

ulus

(MP

a)

i-PPC blend with 2ndi-PPC / 2nd / i-PPC co-ex


0

6

12

18

24

30


Ene

rgy

to B

reak

(J)


Haze

0

20

40

60

80

100


Haz

e (%

)



0

50

100

150

200

250

300


Tear

Res

ista

nce

(g)


Falling Dart Impact

0

200

400

600

800

1000


Dar

t Im

pact

(g)


Advantage Comparison

Falling Dart Impact

MD Tear Resistance

Haze

Protrusion Puncture


Co-extrusionBlend


• How materials are combined affects final properties

• 2nd component characteristics can greatly influence film properties

• Observation - both TPO and PE modified structures exhibited good bubble stability

Experiment #3:Experiment #3:LLDPE vs iLLDPE vs i--PPCPPC

in Coin Co--extruded Structuresextruded Structures

Compare Co-extruded Film Properties

• Replicate ABA i-PPC co-extruded structures with LLDPE as primary component

• Film thickness 90µm

ii--PPCPPC

ii--PPCPPC2nd component

LLDPELLDPE

LLDPELLDPE2nd component

} 30%} 40%} 30%

vs


0

200

400

600

800

1000

mLLDPE POE TPO-A TPO-B TPO-C2nd Component

Mod

ulus

(MP

a)

i-PPC / 2nd / i-PPCLLDPE / 2nd / LLDPE

i-PP

CLL

DPE


0

6

12

18

24

30


Ene

rgy

to B

reak

(J)


i-PP

CLL

DPE


0

200

400

600

800


Tear

Res

ista

nce

(g)


i-PP

CLL

DPE

Falling Dart Impact

0

200

400

600

800

1000


Dar

t Im

pact

(g)


i-PP

CLL

DPE

Haze

0

20

40

60

80

100


Haz

e (%

)


i-PP

CLL

DPE

Advantage Comparison


Haze

Falling Dart Impact

MD Tear Resistance

Protrusion Puncture

LLDPEi-PPC


• Each type of co-extruded structure exhibits advantages but for different properties

– i-PPC: 1% MD secant modulusPuncture resistance

– LLDPE: MD Tear resistanceDart impactHaze

Experiment #4:Experiment #4:Application ExampleApplication Example

Film for Stand Up Pouch

• Film properties to consider

– Stiffness modulus

– Toughness dart impact, puncture & tear resistance

– Optics haze & gloss

– Heat sealable

– Heat resistance

Targeted Structure

• Co-extruded PE film

• Film thickness 76.2 µm

mMDPEmMDPE

mMDPEmMDPEHDPEHDPE

} 10%} 80%} 10%

Strategy

• Use building block approach to design experimental film structures

• Combine techniques of blending and co-extrusion

• Use additives to further modify characteristics

Building Blocks Thought Process

haze & glossClarifying additive

toughnessr-PPC and or TPO blended into core

heat sealabler-PPC skin layer

stiffness & heat resistancePP material

rr--PPC Heat Seal LayerPPC Heat Seal LayerPP Core Layer

} 10%} 80%} 10%

• Structure similar to PE film

• Same film thickness 76.2 µm

Experimental Film Structure

rr--PPC Heat Seal LayerPPC Heat Seal Layer

PP Materials

800.6TPO-B

na6.0r-PPC-C*

6505.5r-PPC-B

10002.0r-PPC-A*

14201.2HPP


* contains clarifier

PE Materials

0.9611.2HDPE0.9330.8mMDPE

Density (g/cc)MIE (g/10 min)Material

Proposed Film Structures

r-PPC-Cr-PPC-Cr-PPC-Cr-PPC-BSkin

70% r-PPC-A +30% TPO-Br-PPC-A70% HPP +

30% r-PPC-CHPPCore

r-PPC-Cr-PPC-Cr-PPC-Cr-PPC-BSkin

Sample #3Sample #2Sample #1PP Control

Equipment Set Up

• Extruders: 3.5 inch2.5 inch60 mm



• BUR: 1.7 : 1


0

200

400

600

800

1000

1200


Mod

ulus

(MP

a)


0

25

50

75

100

125

150


Tear

Res

ista

nce

(g)

Falling Dart Impact

0

40

80

120

160

200


Dar

t Im

pact

(g)


0

4

8

12

16


Ene

rgy

to B

reak

(J)

Haze

0

5

10

15

20

25

30


Haz

e (%

)

45° Gloss

0

20

40

60

80

100


Glo

ss

Heat Seal Strength

0

10

20

30

40

50

80 90 100 110 120 130 140 150 160Sealing Temperature (°C)

Sea

l For

ce (N

)PP ControlSample #3PE Control

sample width: 25.4 mmseal force: 2.757 barseal dwell: 0.5 speel rate: 5.08 mm/s

Advantage Comparison to Target

PP

Falling Dart Impact

45° Gloss

Haze

Protrusion Puncture

≈1% MD Secant Modulus

Heat Seal

MD Tear Resistance

#3#2#1PE


• Experimental PP films

– Excellent optical properties

– Balance of stiffness and toughness

– Heat sealable

• TPO modified structure adds

– Improved tear resistance

– Enhanced bubble stability

In Conclusion

• Polypropylenes can provide a balance of stiffness, toughness and heat resistance to blown film structures

• The range of film properties can be expanded by blending and or co-extruding with other materials

• A polypropylene building block strategy is an effective way to produce unique application solutions

Acknowledgements

A special thank you to Bill Brown, Andy Gillan, Bill Snyder, and Tracey Meder for their contributions in producing the film samples and completing the physical property testing.

Disclaimer

All information contained herein, including, but not limited to, all information developed, prepared or otherwise presented by a third party, is provided by Basell without any warranty whatsoever, and Basell specifically disclaims all express and implied warranties, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose, to the fullest extent allowable by law. In no event shall Basell be liable for any damages, including, but not limited to, direct, indirect, special, consequential, incidental, punitive, or exemplary damages, arising from or related to the information contained herein.

Thank YouPRESENTED BY

Spencer HirataTechnical Service & Applications DevelopmentBasell USA Inc.

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