The ultimate solution for solubility and solvency determination

The ASTM D6038-96 standard describes resin solubility testing by means of cloudpoint determination. This test has been automated by the standard CHEMOTRONIC. A 10 % resin-oil solution is dissolved by heating and stirring, and afterwards cooled down to the point at which the resin becomes insoluble, which is called the cloudpoint. The standard CHEMOTRONIC determines cloudpoints in the range of +50 to +230 °C. This is generally enough for quality control applications.

However, in order to use it as a research instrument a wider temperature range and extra features would be advantageous. The new CHEMOTRONIC COOL offers a larger temperature range of –50 to +250 °C and a lot of new features, such as

• controlled cooling for enhanced accuracy

• powerful stirrer for high solid formulations

• application software with online graphics of all relevant parameters and visualisation functions for data evaluation and documentation

• optional MOT extension unit for automatic solvent dispension at a constant temperature of 25 °C (dilutability test method according to ASTM D5062-96)

All these new features are making the CHEMOTRONIC COOL a valuable tool to test highly soluble or high viscosity resin systems.

Automatic cloudpoint tester CHEMOTRONIC COOL

The new CHEMOTRONIC Cool has been developed for accurate cloudpoint determinations over a wide temperature range. Temperature is one of the most important parameters that influences solubility and rheology of resin solutions. Viscosity measurements on resin solutions are made at the storage temperature of paper, which is defined at 23 or 25° C. As resin solutions must be homogeneous and stable at this temperature, the cloudpoint of these resin solutions must be at a clearly lower temperature, unless one would change the concentration or the solvent. Therefore it is important that one can measure cloudpoints at an well below room temperature and even below zero degree C.

The benefit of the CHEMOTRONIC Cool is that it combines high and low temperature testing in one instrument.

At high temperatures up to +230° C it operates like the standard CHEMOTRONIC and at low temperatures down to –50° C it operates like a refrigerator. At medium temperatures the internal microprocessor controller controls both heating and cooling devices in a way that linear heating and cooling rates are achieved over a wide temperature range.

Standard test procedure for cloudpoint determination

(ASTM D6038-96)

• Fill the test tube with 2 grams of resin
• Add 18 grams of test oil for a 10 % solution
• Insert the test tube into the CHEMOTRONIC and put the temperature sensor on top of it
• Select the CP determination program and press the start button. The resin will automatically be dissolved at high temperature under vigorous stirring and the solution will be cooled down to the point where the resin precipitates
• The internal photocell will detect turbidity. The temperature value at which this occurs is called the cloudpoint. The test result is printed out on the printer automatically. A low cloudpoint indicates good solubility of the resin and visa versa.

Standard test method for mineral oil tolerance MOT

(ASTM D5062-96)

This method can be used in combination with the optional auxiliary dispension unit.

• Fill in the test tube with a varnish that contains 40 % of resin by weight
• Fill n-octane into the dispension unit

• Insert the test tube into the CHEMOTRONIC and put the temperature sensor on top of it

• Select the MOT determination program and press the start button. The varnish will be heated up slowly until stirring action will start. Then it will be cooled down to 25° C slowly and n-octane will be added to it slowly. The quantity of n-octane in ml that makes the resin precipitate is called the MOT value. This volume can automatically be determined by the number of rotations of the piston pump motor drive and is printed out on the printer automatically. A high MOT value indicated good solubility of the resin and visa versa.

How cloudpoint and MOT are related to each other:

Typical temperature program with CHEMOTRONIC Cool :

Recommended by EUROCOMMIT

The CHEMOTRONIC is recommended by the European working group for standardisation of ink test methods EUROCOMMIT as a preferred method for cloudpoint measurements in research and industry. Extensive round-robin tests have proven the reliability of this test method.

Technical specification

• Programmable temperature, stirring speed and turbidity level, program memories for specific test procedures

• Integrated data printer, serial interface RS232 standard