Costron (formerly Bayer) Desmodur 44C Pure MDI 101-68-8

Product Description
DESMODUR 44C is a 4,4′-diphenylmethane diisocyanate monomer with a molecular weight of 250 and is a colorless to light yellow solid at room temperature. This product is mainly used in the production of polyurethane products.

Sampling
Prevent the product from coming into contact with water vapor during sampling.

Specification

Item

Indicator

Unit

Test Method

2,4′-MDI content

≤1.8

% of

20110367601-92

Hydrolyzed chloride content

≤50

ppm

2011-0339304-95

Dimer content*

≤0.1

% of

2012-0346901-92

Typical properties

Item

Indicator

Unit

Test method

Purity (molecular weight 250)

≥99.5

% of

2011-0248603-94

NCO content (theoretical value)

33.6

% of NCO content (theoretical value)

–

Phenyl isocyanate content

≤10

ppm

2011-0339304-95

Viscosity (40℃)

0.1

mPa.s

2011-0313703-95

Density (40℃)

1.19

g/cm³

DIN 51757

Specific heat (cp)

Approx. 1.39

kJ/kg.K

Heat of dissolution

Approx. 102

J/g

Packaging
DESMODUR 44C is available in two ways:
– Liquid (tanker truck)
– Solid (in drums, net weight 225 kg)

Storage

Recommended storage temperature (°C)

<5 (solid), 43±2 (liquid)

Shelf life

≤3 months (solid), ≤3 weeks in tank (liquid) if kept in closed, drained condition

Handling Recommendations
Like all isocyanates, DESMODUR 44C is very sensitive to water and reacts with water to produce insoluble urea and carbon dioxide. In a closed container, the carbon dioxide produced can cause a dangerous rise in container pressure.
Exposure of DESMODUR 44C to air, especially sunlight, accelerates yellowing. It is therefore recommended that liquid DESMODUR 44C be stored in a dry nitrogen atmosphere. yellowing will not normally affect the processability of the product.
DESMODUR 44C is heat sensitive and can form dimers. DESMODUR 44C in the solid state is more susceptible to dimerization at room temperature than in the liquid state at 45°C. For this reason, it is important to store DESMODUR 44C in the solid state at room temperature. Therefore, solid products should be stored below 5°C and melted gradually and rapidly before use. Although the rate of dimerization of the product decreases with decreasing temperature, the stability is still limited even at temperatures below 5℃.
Solid DESMODUR 44C needs to be heated to ≥70°C for melting, a process that will increase the formation of insoluble dimers and possibly deform the drum due to increased pressure at increased temperatures.