Sample Calculations for Polyurethane Formulations:
If the formulation uses 95.26g of solid acrylic resin based on the following polyol and polyisocyanate:
56,100 / 460 = Hydroxyl Number = 122%NCO = 42 X 100 / NCO Equivalent Weight%NCO = 42 X 100 / 183 = 23%
Weight of polyisocyanate required = (NCO EW / OH EW) X Wt solid Resin
Short cut method for calculating the amount of isocyanate:
To adjust NCO / OH to 1.05 / 1.037.90g NCO X 1.05 = 39.79g
(183 / 460) X 95.26g = 37.90g
Chemical Resistance Rating
PARALOID AE-1285
PARALOID AU-830
PARALOID AU-750
PARALOID AU-685HS
PARALOID AU-1166
PARALOID AU-946
PARALOID AU-1453
PARALOID AU-608S
PARALOID AU-1033
0 2 4 6 8 10
PARALOID AE-1285
PARALOID AU-830
PARALOID AU-750
PARALOID AU-685HS
PARALOID AU-1166
PARALOID AU-946
PARALOID AU-1453
PARALOID AU-608S
PARALOID AU-1033
0 2 4 6 8 10
Gloss and Color Ratings
(8-10 rating) = 80-95% gloss retention
(4-7 rating) = 40-80% gloss retention
(1-3 rating) = 20-40% gloss retention
Gloss and Color Retention Avg of QUV-A & QUV-B & 2 years
Florida Exposure
Solvent Acid
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10 = No damage 8-9 = Trace swelling
4-7= Slight swelling 1-3 = Permanent damage
NOTE: The application and features are based on our starting point formulations. These formulations are relative and should not be considered absolute since performance is formulation dependent.
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Equivalents:
% Hydroxyl X 32.5 =
56,100 / (Hydroxyl Number) =
56,100 / Hydroxyl Equivalent Weight =
Polyol Equivalent Weight =
NCO Equivalent Weight =
(Hydroxyl Number X 7.5) / %NCO =
(%NCO / Hydroxyl Number) X 1333 =
Hydroxyl Number
Hydroxyl Equivalent Weight
Hydroxyl Number
17 X 100 / (%Hydroxyl)
42 X 100 / (%NCO)
Wt of NCO to cure 100g of polyol
Parts of polyol to satisfy 100g of NCO
Since we have 95.26 grams of solid resin then:
(122 X 7.5) / 23 = 39.78g of NCO to cure 100g of polyol
(39.78g / 100g) X 95.26 = 37.90g Weight of NCO required.
Acrylic Polyol: 70% Solids & OH EW = 460Polyisocyanate: 100% Solids & NCO EW = 183