HMDI - An excellent application for K-Patents Process Refractometer

A manufacturer of diisocyanate-based products had found that Refractive Index was an ideal method to monitor the rate of reaction in hexamethylene diisocyanate (HDI) reactor. They were looking for a refractometer, which could provide higher accuracy and repeatability. The customer requested an off-line test, where HMDI samples from the process were measured with a K-Patents Process Refractometer and compared to their laboratory refractometer.

Refractometer in HMDI and Diisocyanates

Diisocyanates are a group of low-molecular-weight, aromatic and aliphatic(1) compounds. The most common of these are toluene diisocyanate (TDI), methylene bisphenyl isocyanate (MDI), and hexamethylene diisocyanate (HDI). They are widely used in flexible and rigid foams, fibers, coatings such as paints and varnishes, and elastomers manufacturing. Diisocyanates are increasingly used in the automobile industry, autobody repair and in building insulation materials.

K-Patents Process Refractometer was calibrated to Refractive Index nD scale and all measured samples were within inaccuracy limits of Refractive Index nD +/-0.0002. Also, the integral nozzle design met customer's requirement for easy replacement. The customer was impressed with the test results and placed an order for two sets of Refractometers. A third unit was ordered for their HDI expansion project.

Process Data

Range: 1.44 - 1.48 R.I. @30°C
Process temp: 60-80-90°C
Hazardous location with Ex-proof and shielded interconnecting cable (200m)
Process connection: ANSI 4 inch 150 lbs
Prism wash by solvent, pressure 3 barg

(1) Aliphatic = pertaining to non-aromatic hydrocarbon compounds in which the constituent carbon atoms form open chains compound.