NIOSH Publication No. 2005-151:

NIOSH Pocket Guide to Chemical Hazards

September 2005

Methylene bis(4-cyclohexylisocyanate)

CAS
5124-30-1

CH2[(C6H10)NCO]2

RTECS
NQ9250000
Synonyms & Trade Names

Dicyclohexylmethane 4,4'-diisocyanate; DMDI; bis(4-Isocyanatocyclohexyl)methane; HMDI; Hydrogenated MDI; Reduced MDI; Saturated MDI
DOT ID & Guide

Exposure
Limits

NIOSH REL: C 0.01 ppm (0.11 mg/m3)
OSHA PEL: none
IDLH
N.D. See: IDLH INDEX
Conversion
1 ppm = 10.73 mg/m3
Physical Description
Clear, colorless to light-yellow liquid.
MW: 262.4
BP: ?
FRZ: <14°F
Sol: Reacts
VP(77°F): 0.001 mmHg
IP: ?

Sp.Gr(77°F): 1.07
Fl.P: >395°F
UEL: ?
LEL: ?

Class IIIB Combustible Liquid: Fl.P. at or above 200F.
Incompatibilities & Reactivities

Water, ethanol, alcohols, amines, bases, acids, organotin catalysts [Note: May slowly polymerize if heated above 122°F.]
Measurement Methods
NIOSH 5525; OSHA PV2092
See: NMAM or OSHA Methods
Personal Protection & Sanitation
(See protection)
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
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
Irritation eyes, skin, respiratory system; skin, respiratory sensitization; chest tightness, dyspnea (breathing difficulty), cough, dry throat, wheezing, pulmonary edema; skin blisters
Target Organs
Eyes, skin, respiratory system
See also: INTRODUCTION