Applications
Desmodur® N 75 BA is used primarily as the hardener component for lightfast two-component polyurethane coatings with high resistance to chemicals and weathering, very good gloss retention and outstanding mechanical properties. Preferred co-reactants are polyacrylate or polyester polyols.The main applications for systems based on Desmodur® N 75 BA are as air- and force-drying coatings for automotive and industrial finishing, for wood, furniture and plastics and for corrosion protection.
Form supplied
approx. 75 % in n-butyl acetate
Specification
| Property | Test Condition | Value | Unit | Standard |
|---|---|---|---|---|
| NCO content | 16,5 ± 0,3 | % | M105-ISO 11909 | |
| Non-volatile content | (2.2 g/120 min/100 °C) | 75 ± 1 | % | M020-ISO 3251 |
| Viscosity at 23 °C | 160 ± 50 | mPa*s | M014-ISO 3219/A.3 | |
| Color value (Hazen) | ≤ 40 | M017-EN 1557 | ||
| Monomeric HDI | < 0,38 | % | M106-ISO 10283 |
Typical Values
| Property | Test Condition | Value | Unit | Standard |
|---|---|---|---|---|
| Viscosity at 25 °C | approx. 140 | mPa*s | M014-ISO 3219/A.3 | |
| Equivalent weight | approx. 255 | |||
| Flash point | approx. 35 | °C | DIN 53 213/1 | |
| Density at 20 °C | approx. 1,07 | g/ml | DIN EN ISO 2811 |
Solubility / thinnability
Desmodur® N 75 BA can be thinned with esters, ketones and aromatic hydrocarbons such as methoxypropylacetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, toluene, xylene, solvent naphtha® 100 and mixtures thereof. Generally speaking, it has good compatibility with the solvents listed. However, the solutions formed must be tested for their storage stability. Only PU grade solvents should be used (max. 0.05 % water, absence of reactive groups such as hydroxyl or amino groups). Butyl acetate and ethyl acetate are not recommended as the sole or main solvents for thinning as, at low solids contents, they may result in a lack of stability of the Desmodur® solutions. Aliphatic hydrocarbons are unsuitable as solvents.Desmodur® N 75 BA should not be thinned to below a solids content of 40 %. Prolonged storage of a solution with a lower binder content may result in turbidity and sedimentation.
Compatibility
Generally speaking, Desmodur® N 75 BA can be mixed with the following products: aliphatic polyisocyanates such as Desmodur® N 3200, ultra N 3300, N 3400, ultra N 3600 and Desmodur® ultra Z 4470; aromatic polyisocyanates such as Desmodur® L/ultra L, HL and IL/ultra IL; polyester polyols such as Desmophen® 651 and 670; polyacrylates; polyether polyols such as Desmophen® 1380 BT. However, the compatibility of the combinations used should always be tested.
Storage
Storage in original sealed Covestro container. Recommended storage temperature: 0 - 30 °C. Protect from moisture, heat and foreign material. General information: The product is sensitive to moisture. Storage at higher temperatures will result in increase of color and viscosity.
Storage time
Covestro represents that, for a period of nine months following the day of shipment as stated in the respective transport documents, the product will meet the specifications or values set forth in section "specifications or characteristic data" above, what ever is applicable, provided that the product is stored in full compliance with the storage conditions set forth in and referenced under section "storage" above and is otherwise handled appropriately.The lapse of the nine months period does not necessarily mean that the product no longer meets specifications or the set values. However, prior to using said product, Covestro recommends to test such a product if it still meets the specifications or the set values. Covestro does not make any representation regarding the product after the lapse of the nine months period and Covestro shall not be responsible or liable in any way for the product failing to meet specifications or the set values after the lapse of the nine months period.
