α-Methyl Styrene Dimer

        < Chain Transfer Agent >
 1 Introduction

NOFMER® MSD is a suitable Chain Transfer Agent (CTA) for polymers containing styrene such as PS, AS polymers or SB latexes. In addition, NOFMER®MSD can be used as an addition agent with functions of a crosslinking co-agent and a retarder for LDPE crosslinking.

Because of these features, NOFMER®MSD is used in the production of coating materials, high–voltage electric cables and others.

 2 Chemical Structure

"2,4-diphenyl-4-methyl-1-pentene" is a main component in NOFMER® MSD. The chemical structure is as follows.

2,4-Diphenyl-4-methyl-1-pentene
(α-Methyl Styrene Dimer)
(CAS Registry No: 6362-80-7)

 3 Physical Properties
Table. Physical Properties
Appearance Colorless liquid
Purity ≧ 93%
Specific Gravity 0.992 (20 ˚C)
Viscosity 18.0 cps (20 ˚C)
BoilingPoint 1013Pa 300-318 ˚C
798Pa 150-152 ˚C
Flash point 150 ˚C 150 ˚C

 4 Feature of NOFMER®MSD

NOFMER® MSD works as a CTA for PS, ASpolymers or SB latexes, etc.
NOFMER® MSD works as a crosslinking co-agent and a retarder for LDPEcrosslinking (XLPE).
NOFMER® MSD has less odor compared tomercaptans or other retarders (BHT etc).

 

 5 Application of NOFMER®MSD

NOFMER® MSD is used in the production of coating materials as a CTA or covering of high–voltage electric cables as a crosslinking co-agent and a retarder.

 

 6 Technical date of NOFMER®MSD

In the point of view of the chain transfer constant,NOFMER® MSD is a suitable CTA because an excellent transfer constant should be between 0.01 and 1.0.
Furthermore, NOFMER® MSD can control lowmolecular weight andmolecular weight distribution than NDM.
In addition, NOFMER® MSD can reduce molecular weight with increasing dosage, while keeping molecularweight distribution.

 

Table. Chain transfer constant (Ctr)
Chain transfer constant Ctr at 60˚C Monomer
St MMA St MMA
NOFMER®MSD 0.21 0.074
n-butylmercaptan (NBM) 22 0.67
t-butylmercaptan (TBM) 3.7 -
n-dodecylmercaptan (NDM) 14.8 -
Ctr ofMercaptans; PolymerHandbook 3rd edition

 

Table. Polymerization of styrene
CTA Mw × 10⁻⁴ Mw/Mn
None 32.1 2.8
NOFMER® MSD 0.5 wt% 11.1 2.8
1.0 wt% 8.0 2.6
2.0 wt% 4.9 2.6
n-dodecylmercaptan (NDM) 0.5 wt% 25.3 6.8
1.0 wt% 26.4 11.0
2.0 wt% 23.7 19.0

 

 

 7 Technical data of NOFMER®MSD as a crosslinking co-agent and a retarder

NOFMER® MSD can make a highly crosslinked polymer as a crosslinking co-agent at crosslinking temperature (180˚C). In addition, NOFMER® MSD can prevent scorch effectively as a retarder at kneading temperature (145˚C). NOFMER® MSD haswell balanced results in both torque value and scorch time.

Fig. Time-torque curve for LDPEcrosslinking

 

Table. Comparison data of NOFMER® MSD with other additives
Additives  
Type Amount (phr) Max. torque(N.m)(180˚C) Scorch time˟˟ (min) (145˚C)
- - 0.3 6
NOFMER® MSD      1.0 0.45 17
Co-agent TAIC* 1.0 0.44 3
TMPT 1.0 0.35 7
Retarder BHT** 0.2 0.28 9
2-Mercaptobenzothiazol 0.5 0.1 25

*TAIC: Triallyl isocyanurate, TMPT; Trimethylolpropane trimethacrylate
**BHT; 2,6-Di-t-butyl-p-cresol
˟˟Scorch time: Time to reach 10% of Max. torque at scorch-test temp (145˚C).

 

 8 Packing Information

◆ Package style: Drum
◆ Quantity: 200KG(440 lb)
◆ Drum size: Φ585 × 890 mm (Φ23.0 × 35.0 in)
◆ Transportation Info: Class 9,UN3082, PGIII