Blocked aliphatic polyisocyanate curing agent hardener based on IPDI Desmodur BL 2078/2
Product Description
Aliphatic polyisocyanate (HDI biuret).
Blocked aliphatic polyisocyanate based on IPDI. In combination with OH-functional polyols, preferably Desmophen ® T-grade OH-functional polyesters, in the formulation of lightfast, one-component polyurethane baking coatings, especially in coil and can coating applications, and as an additive to conventional baking systems to improve adhesion and elasticity. Crosslinking agent certified for use in food contact applications*) for the production of packaging coatings for the food industry.
Product Introduction
|
Other data* Property |
Value |
Unit of measurement |
Method |
|
Viscosity at 23°C |
1,750 ± 500 |
mPa·s |
M014-ISO 3219/A.3 |
|
Non-volatile content (0.2 g/60 min/140 °C) |
60 ± 2 |
% |
DIN EN ISO 3251 |
|
NCO content , blocked |
approx. 7 |
% |
|
|
Equivalent weight |
approx. 600 |
|
|
Properties / Applications
Desmodur®
BL 2078/2 was developed as a hardener for the formulation of
lightfast, one-component polyurethane baking coatings and is used primarily in coil and can coating applications.
With equivalent crosslinking (BNCO:OH = 1.0:1.0) with Desmophen® T 1775,corrosion-resistant coil coating primers and weather-stable coil coating topcoats with balanced hardness and elasticity properties can be formulated.
The required baking temperature (PMT = peak metal temperature) can be lowered by catalysis with 0.5 – 1.0 % dibutyltin dilaurate (DBTL) without affecting the storage stability of the finished coating. With a PMT of 232 °C,
both primer and topcoat can be applied with a dry film thickness of up to 50 µm, so that the total thickness of a two-coat system can be as much as 100 µm.
The product can be used in combination with OH-functional
polyesters such as Desmophen®T 1775 and phenolic, melamine and benzoguanamine resins for the formulation of highly flexible and sterilization-resistant can coatings that cure at 200 °C within 12 minutes.
For the formulation of packaging coatings that are also suitable
for food contact applications, we recommend a mixed system of Desmophen® T 1775 / SFC 112 / Cymel® 1123 / Desmodur® BL 2078/2 in the ratio 50 : 20 : 25 : 5 % by wt.
Storage
- Storage in original sealed Covestro container.
- Recommended storage temperature: 0 - 30 °C.
- Protect from moisture, frost, heat and foreign material.
General information: Storage at higher temperatures will result in increase of color and viscosity. Storage at significant lower temperatures will result in solidification. This solidification is reversible by briefly heating the product without adversely affecting the quality of the product.
