α-Methyl Styrene Dimer
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.
"2,4-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)
| 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 | |
① NOFMER® MSD works as a CTA for PS, ASpolymers or SB latexes, etc.
② NOFMER® MSD works as a crosslinking co-agent and a retarder for LDPEcrosslinking (XLPE).
③ NOFMER® MSD has less odor compared tomercaptans or other retarders (BHT etc).
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.
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 | - |
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 | |
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).
◆ Package style: Drum
◆ Quantity: 200KG(440 lb)
◆ Drum size: Φ585 × 890 mm (Φ23.0 × 35.0 in)
◆ Transportation Info: Class 9,UN3082, PGIII
