Bayhydrol A XP 2770
Type Aqueous hydroxyfunctional polyacrylic dispersion
Form supplied approx. 44.5 % in water/Dowanol® PnB, neutralized with
dimethyl amino ethanol in the ratio approx.
50.2 : 3.6 : 1.7
Uses Waterborne 2K-Polyurethane varnishes in combination
with aliphatic Polyisocyanates
Characteristic data*
Property Value Unit of measurement Method
Viscosity at 23 °C, approx. 1,000 mPa·s DIN EN ISO 3219/A.3
D = approx. 40 s-1
Non-volatile content approx. 44.5 % DIN EN ISO 3251
(1 g/1 h/125 °C/convection oven)
pH 8.0 DIN ISO 976
(tested 10 % in demineralised water)
*These values are provisional. Binding supply specifications will not be
available until the final product data sheet is published.
Other data**
Property Value Unit of measurement Method
Hydroxyl content approx. 3.9 %
(solvent free, calculated)
Acid value approx. 11.5 mg KOH/g DIN EN ISO 2114
Density at 20 °C approx. 1.06 g/ml DIN EN ISO 2811
**These values provide general information.
Bayhydrol A XP 2770
Solubility / thinnability Bayhydrol® A XP 2770 can be thinned with water in
any ratio.
Compatibility Suitable co-reactants for the formulation of
aqueous two-component polyurethane systems include
Desmodur® N 3400, N 3600, N 3800 or N 3900,
Bayhydur® 3100, 304, 305, 401-70, XP 2487/1,
XP 2655 or XP 2759.
Properties / Applications Bayhydrol® A XP 2770 is a hydroxyfunctional
polyacrylic dispersion which can be thinned with
water to application viscosity. Bayhydrol® A XP
2770 combined with aliphatic polyisocyanates
yields high-gloss top coats which can be dried
at room temperature or force-dried, e.g.at 80℃
The cured paint films are hard and flexible with
outstanding resistance to solvents and water and
excellent weatherability.
When properly formulated, e.g.in combination with
Bayhydur® 304 in an NCO / OH ratio of 1.5 : 1,
the pot life is approx. 4 hours.
Bayhydrol® A XP 2770 has good pigment wetting
properties and high shear stability. Bead mills
have proved suitable as grinding equipment. Only
pigments and extenders with a minimum water-soluble
content should be used. Given the many pigments
and extenders available, compatibility testing
should always be carried out.
When mixing Bayhydur® or Desmodur® into the mill
base, a thickener must be added to ensure a high
shear effect.
The addition of approximately 0.4 % Borchigen®
PW 25 (calculated on the solid binder) has proved
suitable for formulations based on Bayhydrol® A
XP 2770.
Levelling and substrate wetting can be optimised
by adding, for example Byk® 349 and Byk® 378.
Byk® 011 has proved to be a suitable antifoam.
Application and formulation equipment can be cleaned
with water, alkaline cleaning agents or isopropanol.
Storage - Storage in original sealed Bayer MaterialScience
containers.
- Recommended storage temperature: > 0 - 30 °C.
- Protect from frost, heat and foreign material.
General information: Short-time cooling down to
-18 °C does not typically damage the product.
Prolonged freezing can damage the product
irreversibly.
Prolonged storage at higher temperatures may result
in a decrease of viscosity and/or an increase of
average particle size, possibly resulting in
sedimentation or coagulation.
The viscosity of the product is largely governed
by the pH. As the pH may decrease during storage,
a decrease in viscosity is also to be expected. The
viscosity can be adjusted to its original value by
the addition of small amounts of an aqueous 10 %
solution of dimethyl ethanol amine.
Contamination with certain bacteria, fungi or algae
may render the product unusable.
Storage time Bayer MaterialScience represents that, for a period
of six 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 six months period does not
necessarily mean that the product no longer meets
specifications or the set values. However, prior to
using said product, Bayer MaterialScience recommends
to test such a product if it still meets the
specifications or the set values. Bayer
MaterialScience does not make any representation
regarding the product after the lapse of the six
months period and Bayer MaterialScience 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 six months
period
Safety Hazards identification Not classified as a hazardous
product as per Council Directive 2006/121/EC or
1999/45/EC.
The safety data sheet should be observed.This contains
information on labeling, transport and storage as well
as on handling, product safety and ecology.
Important This is a Trial Product of which we do not yet have
extensive experience.
No guarantee can therefore be given regarding the
behaviour of the product during processing or use.