Desmodur-HDI based curing agent

Covestro Desmodur N3790 BA HDI polyisocyanate curing agent light fast drying

type	Aliphatic polyisocyanate (high functional hexamethylene diisocyanate trimer)
form of supply	About 90% butyl acetate solution
use	Used as a lightfast, fast drying polyurethane coating hardener component

Specification

characteristic	Numerical value	Units of measurement	method
NCO content	17.8±0.5	%	DIN EN ISO 11909
Non-volatile content (2.2g/120min/100°C)	90±1	%	DIN EN ISO 3251
Viscosity, 23°C	1800±500	mPa·s	DIN ENISO 3219/A.3
Color value (Hazen)	≤40		DIN EN 1557
HDI monomer	≤0.30	%	DIN EN ISO 10283

Other data*

characteristic	Numerical value	Units of measurement	method
Viscosity, 23°C	about 1600	mPa·s	DIN EN ISO 3219/A.3
equivalent	about 236
Flash point	about 42	°C	DIN 53213/1
Density@20°C	about 1.13	g/ml	DIN EN ISO 2811

*This data is general information and is not part of the product specification.

Solubility / dilution
Desmodur® 3790BA can be used with esters, ketones, aromatic hydrocarbon solvents such as: ethyl acetate, butyl acetate, methoxypropyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, toluene, xylene, No. 100 naphtha solvent and its mixture dilution. Generally have good miscibility with these solvents.
However, the storage stability of the resulting solution must be tested. Polyurethane grade solvents should be used (less than 0.05% water, no hydroxyl or amino reactive groups). Aliphatic hydrocarbons are not suitable solvents. Desmodur® N3790 should not be diluted below 40% solids. Solutions with low binder content may experience turbidity and precipitation after prolonged storage.

compatibility
Desmodur® N3790 can generally be used with the following products. Namely: Desmodur® N100, N75, N3200, N3400, N3600 and Desmodur® Z4470 aliphatic polyisocyanates; Desmodur® L, HL and IL aromatic polyisocyanates; Desmophen® 670 polyester polyols; Desmophen® A polyisocyanates Acrylate. However, the compatibility of the prepared solution must be tested. Desmodur® N3790 is not compatible with branched polyester polyols such as Desmophen® 651 or polyether polyols such as Desmophen® 1380BT.

Features/Applications
Desmodur® N3790 is mainly used as the curing agent component of lightfast two-component polyurethane coatings with excellent chemical and weather resistance, outstanding gloss retention and excellent mechanical properties. Desirable co-reactants are polyacrylates or polyester polyols. Coating systems formulated with Desmodur® N3790 are suitable for air drying or baking for OEM, automotive refinish, transportation, industrial and plastic finishing.

store
Desmodur® N3790 is sensitive to moisture and should therefore be stored in its original sealed container. When properly stored at room temperature, this product has a shelf life of at least 6 months.