Methylene bis(4-cyclohexylisocyanate)

Synonyms & Trade Names
Dicyclohexylmethane 4,4'-diisocyanate, DMDI, HMDI, Hydrogenated MDI, bis(4-Isocyanatocyclohexyl)methane, Reduced MDI, Saturated MDI
CAS No.
5124-30-1
RTECS No.
DOT ID & Guide
Formula
CH₂[(C₆H₁₀)NCO]₂
Conversion
1 ppm = 10.73 mg/m3
IDLH
N.D.
See: IDLH INDEX
Exposure Limits
NIOSH REL
C 0.01 ppm (0.11 mg/m3)
OSHA PEL
none See Appendix G
Measurement Methods
NIOSH 5525;
OSHA PV2092
See: NMAM or OSHA Methods
Physical Description
Clear, colorless to light-yellow liquid.
Molecular Weight
262.4
Boiling Point
?
Freezing Point
<14°F
Solubility
Reacts
Vapor Pressure
(77°F): 0.001 mmHg
Ionization Potential
?
Specific Gravity
(77°F): 1.07
Flash Point
>395°F
Upper Explosive Limit
?
Lower Explosive Limit
?
Class IIIB Combustible Liquid: Fl.P. at or above 200°F.
Incompatibilities & Reactivities
Water, ethanol, alcohols, amines, bases, acids, organotin catalysts [Note: May slowly polymerize if heated above 122°F.]
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
irritation eyes, skin, respiratory system; skin, resp sensitization; chest tightness, dyspnea (breathing difficulty), cough, dry throat, wheezing, pulmonary edema; skin blisters
Target Organs
Eyes, skin, respiratory system
Personal Protection/Sanitation
(See protection codes)
Skin:Prevent skin contact
Eyes:Prevent eye contact
Wash skin:When contaminated
Remove:When wet or contaminated
Change:No recommendation
Provide:Quick drench
First Aid
(See procedures)
Eye:Irrigate immediately
Skin:Water flush immediately
Breathing:Respiratory support
Swallow:Medical attention immediately
Respirator Recommendations

NIOSH

Up to 0.1 ppm:
(APF = 10) Any supplied-air respirator*

Up to 0.25 ppm:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode*

Up to 0.5 ppm:
(APF = 50) Any self-contained breathing apparatus with a full facepiece
(APF = 50) Any supplied-air respirator with a full facepiece

Up to 1 ppm:
(APF = 2000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode

Emergency or planned entry into unknown concentrations or IDLH conditions:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus

Escape:
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister
Any appropriate escape-type, self-contained breathing apparatus

Important additional information about respirator selection

See also
Page last reviewed: October 30, 2019