Checking OH number

I would like to Know if there´s a faster method to check OH number of a polyester resin than the pyridine´s method (that takes 1 hours to be completed).

Thank you very much,

Rodrigo Toledo

You can get a rough idea by adding a known excess of isocyanate and then doing an NCO test on the result. This will actually give you the value for all of the active hydrogen parts, not just OH, but this is a very useful test as it mimics exactly what happens when you want to do a reaction with isocyanate to make a PU. doesn't save you much time but it avoids having to handle pyridine.

Colin

Colin,

Thank you very much. I=B4ll try your tip. As I=B4m starting to study/develop polyester resin, I=B4ve a basic question:

I=B4ve the following formulation: Kilograms %

=C1cido Ad=EDpico 2081,7918 62,46 Monoetilenoglicol - MEG 630,2703 18,91 Dietilenoglicol - DEG 620,9379 18,63 Tetrabutiltitanato 0,03333 0,001

And I was expecting a OH number of 55 (70 is the theoretical number )

The practical value of OH was 42.5, so I lost to many glicols. What is best calculation to correct this batch ? I mean, what is the amount of glicols to be added to reach the target of OH number-55 ?

Thank you very much,

Best regards,

Rodrgio Toledo

Col> Hi,