Melt Strength

The R&D Trends of High The R&D Trends of High

Performance Polypropylene Performance Polypropylene

(High Melt Strength PP) (High Melt Strength PP)

Daeduk R&D Center 2007. 10. 26.

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목차목차 목차목차

호남석유화학㈜ 소개

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폴리올레핀 기술 개발 동향 고용융장력 폴리프로필렌

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개요개요

개요개요^l

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롯데 롯데 롯데

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3사

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지분 지분 지분

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사업장사업장

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사업군 사업군 사업군

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주요 주요 주요

주요 생산생산생산 품목생산 품목품목품목^l

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위상위상

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신규사업신규사업

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비전비전

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대덕연구소 대덕연구소 대덕연구소

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역할역할

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위상위상

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비전비전

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Polypropylene

Chemical Structure

Crystalline Polymer

Crystallinity : 52%

Non-Polar Polymer

Wetting Tension : 29~31 dynes/cm ( PA : 33 ~ 46 dynes/cm )

3

Triclinic

γ form

3

Pseudohexagonal

β form

3

Monoclinic

α form

Helix Crystal System

Form

POM Image of Spherulites Black : Carbon

White : Hydrogen

CH

CH CH

n

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Feature of Polypropylene

Advantages

Mechanical Properties,

Chemical Resistance, Durability Heat Resistance

Processibility : Injection, Extrusion Clean, Eco-Friendly Material

Low Cost

Disadvantages

Low Melt Strength :

Poor processibility for Foam, Thermoforming Poor Adhesive Properties :

Hard to Paint, Print, and Dye

Poor Compatibilities with Polar Material

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Trends of Polyolefin Characterization

저밀도

High High Stiffness Stiffness

High Melt High Melt

Strength Strength

High Flow High Flow Polar

Polar Properties Properties Low Low

Density

Density

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Nano Hybrid Reactor Made

Trends of Polyolefin Characterization

High Flow High Flow Polar

Polar Properties Properties

High Stiffness

Low Low Density Density

High Melt

High Melt

Strength

Strength

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Trends of Polyolefin Characterization

High High Stiffness Stiffness High Melt

High Melt Strength Strength

High High Flow Flow

Low Low Density Density

Polar Properties

Solution Reactive Extrusion

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Trends of Polyolefin Characterization

High Melt High Melt Strength Strength High Flow

High Flow

Low Density

Polar Polar Properties Properties

High High Stiffness Stiffness

Metallocene

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Process of High Melt Strength PP

Polar Polar Property Property Low Low

Density Density

High Melt Strength

High High Stiffness Stiffness

High High Flow Flow

○ ○ ○

○

◎ ◎ ◎

◎

× × ×

× Cost

◎

◎ ◎

◎

△

△ △

△

◎

◎ ◎

◎ Performance

Maker

Reactive Extrusion Reactor Made

Type Ionizing Electron

Radiation

Method

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Melt Strength Behavior of Polymer

Crystalline Polymer :

Very Narrow Processing Temperature Window

T

T

Temperature

M el t S tr en g th

Crystalline Polymer

Amorphous Polymer

Optimum

Melt Strength

for Expansion

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Melt Strength

Factor

Molecular Weight Side Chain

Intermolecular Interaction

Influence on Processing

Blow Molding : Parison Draw Down Thermoforming : Deep Drawing

Inflation Film : Bubble Rupture

Foaming : Cell Growth, Coalescent & Rupture

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Why HMS-PP ?

Material Unification

Recycling : Need not Classify

Food Package

Less Odor

Microwave Oven

Plank Foam

Better Impact & Chemical Resistance Less Harmful Combustion Gas

Automotive Door Trim PP Core

X-linked PP Foam (Urethane Foam)

TPO Skin

PP Core HMSPP Foam

TPO Skin

PS Foam PS Thermoform

HMSPP Foam HMSPP Thermoform

PS Foam HMSPP Foam

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Evaluation of Melt Strength

Equipment : Molten Rheometer (Toyoseiki, Japan)

Oil Bath

Specimen Silicon Oil

Load Cell

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Melt Strength with Molecular Weight

0 2 4 6 8 10 12 14

0 10 20 30 40 50

Time(sec)

Melt Tension(g)

MI : 0.5 MI : 1.0 MI : 2.0 MI : 4.0

313,200 425,900 415,800 492,000

M

53,700 74,500 78,000 96,400

M

4.0 Homo PP 1.0

2.0 Block PP 0.5

MI (g/10min)

Test Temperature : 200 ℃ ℃ ℃ ℃

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High Melt Strength is not Real Solution!

Melt Strength

PP (MI : 0.5) >> LDPE (MI : 5.3)

Processibility of Foaming

PP ^{(MI : 0.5)} << LDPE ^{(MI : 5.3)}

Processing Window of PP is not improved.

Too High Melt Strength is not good for

Cell Growth at early stage in Foaming Process

Other Factor is more Important

in Crystalline Polymer for Foaming!

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Melt Strength with Side Branch

Elongational Viscosity

dt dt d dL

dt dL L dt

d ln( )

1 =

=

= ε ε &

0

ln L

= L ε

extension of

rate

stress tensile

λ =

ε σ σ

&

⋅ =

=

dt dL L

1

10⁰ 10¹ 10² 10³

10⁴ 10⁵

Viscosity (Pa.s)

Time (sec)

Tension (g)

Time (sec)

10 20 30

5 10

15 Strain Hardening

HDPE LDPE

HDPE

LDPE

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Basic Idea

Improve Processing Window of PP

Cross-Linking : Non-recyclable, High Cost

Decreasing Crystallinity : Decrease Mechanical Properties Introducing Side Branch : Improve Strain Hardening

HMSPP

General PP

20 10

5 2

1 0.2 0.5

0.2 20 10 5 2 1 0.5

MI (g/10min)

Melt Tension (g)

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Characteristic of HMSPP – Molecular Weight

HMS PP Conventional PP

2.73 4.12

1,208,000 443,300

107,600 0.5

Conventional PP

2.98 5.81

1,277,000 428,300

73,800 3

HMSPP

M

/M

M

/M

M

M

M

MI

PP

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Characteristic of HMSPP – Melt Strength

Time(sec)

0 10 20 30 40 50

M e lt T e n si o n (g )

0 1 2 3 4

HMS PP (HPC) HMS PP (Maker A) Conventional PP

Test Temperature : 200 ℃ ℃ ℃ ℃

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Characteristic of HMSPP – Elongational Viscosity

Time(sec)

1 10 100

Vi sc os ity (p oi se )

1e+5 1e+6

HMS PP (HPC) HMS PP (Maker A) Conventional PP

Test Temperature : 200 ℃℃℃℃

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Characteristic of HMSPP – Mechanical Properties

℃

℃

℃

℃ Mpa kg∙∙∙∙cm/cm

Mpa g/10min

Unit Maker A Honam

Item

3 3

3 MI

Homo PP 116

35 4.6 1,650

Conventional PP

Homo HMS Homo HMS

Notes

12.2 6.7

IZOD Impact Strength

40 37

Tensile Strength

135 2,100 1,620

Flexural Modulus

118 Heat Distortion Temp .

HMSPP

Mechanical Properties

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Characteristic of HMSPP – Foaming Processibility

20 times Foaming

20 times Foaming 60 60 times Foaming times Foaming

Process : Extrusion Foaming Blowing Agent : CO2

Processing Temperature : 160 ~ 200 ℃ ℃ ℃ ℃

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Applications of HMSPP

Foam Sheet

Plank Foam : Construction & Industry Food Tray

Automotive Interior Parts Stationery Cover Sheet

Thermoforming

Tray Cup

Extrusion Coating

Lamination Film : Improve neck-in

Blow Molding

Blown Film

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Conclusions

Introduction of long chain branch on linear PP back- bone increase melt strength and strain hardening remarkably.

High melt strength PP has improved mechanical properties.

It can make extend processing temperature window, because of the strain hardening effect which can

increase melt strength of polypropylene melt at high temperature.

High melt strength PP which has high strain

hardening effect can make 20 ~ 60 times expanded

foam in no cross-linking.

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Thank you very much for your attention!

Daeduk R&D Center

Honam Petrochemical Corp.