Discoloration Resistant LLDPE Rotomolding Resin

PTT GLOBAL CHEMICAL PLC.

1 1

Rotational Molding Process

Ref: Practical Guide to Rotational Moulding Roy J. Crawford and Mark P. Kearns 2003

2 2

Polyolefin discoloration pathway

3 3

How plastic discolored from “ROTOMOLDING PROCESS”?

• Exhaust gas environment

• Additive formulations

NOX/SOX

Radical

Ref: http://www.ampacet.com/faqs/yellowing-and-pinking-white-pe-pp/

4 4

Exhaust gas environment

5 5

Gas Fading Experiment

Samples Before fading After 96 hs

fading

B + phosphite -0.91 0.28

A + phosphite -1,42 0.87

-2

-1

0

1

B A Y

I valu

es

Formulation

Before fading

96 hrs fading

6 6

Discoloration Mechanism from Additives

Quinone Methine Trap

Yellow Intermediate Yellow Substance

Radical

Colorless irreversible substance

Phenolic AO

7 7

Effect of Quinone Methine Trap amount

formulation Initial YI After aging (210 C 30 min)

VIR 0.04 8.68

FORM A -1.81 13.16

FORM B -1.54 7.83

FORM C -1.41 7.01

FORM D -2.81 4.51

-5

0

5

10

15

VIR

FO

RM

A

FO

RM

B

FO

RM

C

FO

RM

D

YI

Formulations

Initial YI

Aging YI

VIR : LL9641 base resin

Formulation: phenolic, phosphite,UV8 Light stabilizer, Lubricating agent

FORM A, B, C, D (amount of Quinone Methine Trap A<B<C<D)

8 8

Consistency of Compounding

formulation After aging (210 C 30 min)

Replicate I 4.92

Replicate II 4.85

Replicate III 4.51

0 2 4 6 8

10

Replicate I Replicate II Replicate III

YI

Formulations

Aging YI

Aging YI

Sample: phenolic, phosphite, Light stabilizer, Lubricating agent (FORM D)

9

Private & Confidential

Discoloration Resistance Chemistry

UV radiation

Heat & Oxygen

AO1

AO2

LS

Yellow

Intermediate Scavenger

Colorless compound

Yellow Intermediate Yellow Substance

Radical Phenolic AO

10

Private & Confidential

Rotomolding Article from Discoloration Resistance Resin

11 11

Acknowledgement

PTT Global Chemical PLC.

Science an Innovation Center (S&I)

BU-POL, PTTPM, CO-DI-PM Department

Project team (Mr.Wiraphing K, Ms. Patima W. and Ms. Chonticha C.)