Trade Name: TODI
Similar Name: 3,3'-Dimethyl-4,4'-biphenylene diisocyanate; Bitolylene Diisocyanate; benzoxadiazole; 4,4'-Diisocyanato-3,3'-dimethylbiphenyl
Molecular Formula:C16H12N2O2

HARTDUR 118 (TODI / 3,3'-Dimethyl-4,4'-biphenylene diisocyanate), CAS number 91-97-4, is an universal additive for improving mechanical and chemical properties on urethane elastomers.  The two benzene rings in the TODI molecule have a symmetrical structure. Due to the steric hindrance of the o-methyl group, the reaction activity is lower than that of TDI and MDI.

Comparing to NDI-based polyurethane elastomers, elastomers based on TODI, oligomer polyols and MOCA have similar physical properties, such as excellent heat resistance, hydrolysis resistance and mechanical properties. Comparing with rubbers, plastics and metals, TODI-based elastomers have much more advantages, they are durable, heat resistance and hydrolysis resistance. TODI-based elastomers offer superior mechanical properties to be applied on working under harsh conditions and/or environment. Furthermore, resulting from its longer pot life, TODI-based prepolymer is easier to handle in comparison to NDI-based products.


50kgs/iron drum.

It can be packaged on demand. Please inquire.      

HARTDUR 118 (TODI) is pure 3,3'-Dimethyl-4,4'-biphenyldiisocyanate (TODI) and is supplied in the form of fine milky white, or occasionally yellowish white, granular solid. Its vapor pressure at room temperature is below 10-4mbar. Permissible in the air at working places according to the Federal Republic of Germany is 0.01 ppm = 0.087 mg/m3. This value is not allowed to exceed even for short periods. Being exceptionally reactive, TODI must be treated as a dangerous material and it must therefore be handled with care. The potential risks of HARTDUR 118 (TODI) depend mainly on the extent to which isocyanate dust, vapors, or aerosols are formed during the processing of this product. The circumstances and operations in which workers may be exposed to HARTDUR 118 (TODI) in any of these forms are as follows: dust may rise from the solid material while it is being weighed or introduced into reaction vessels; vapors and aerosols are formed in the cross linking of hot prepolymer batches containing an excess of TODI and in the production of castings (the aerosols owe their formation to the cooling and condensation of hot isocyanate vapors).

Molecular formulaC16H12N2O2
Molecular weight264.2787
Density1.12 g/cm3
Melting point70-72°C
Boiling point384.8°C at 760 mmHg
Flash point158.8°C
Vapor pressure4E-06 mmHg at 25°C

Storage  Caution:

HARTDUR 118(TODI) is sensitive to moisture. Water reacts with all diisocyanates to form insoluble urea derivatives. HARTDUR 118 (TODI) should be stored in tightly sealed containers in cool and dry conditions. Do NOT put TODI along with food and avoid exposing in an environment above 30℃. After using, the lid must be sealed immediately in case of dysfunction. Under suitable storage conditions, TODI is valid for six months at least with effect from the date on which it’s delivered.


With its outstanding mechanical and chemical properties, TODI-based elastomers are widely applied on various fields. First of all, sealing components, such as oil sealing, piston ring, water seals and so on. Then, automobile parts are another major application of TODI, including bumper extensions, shock absorbers, grills and etc. Besides, high-ended industrial usage, i.e. belts, rolls, casters. Furthermore, TODI is an important coating agent in electric field and as artificial organs in medical equipment.