Method for Detection of Impurities in Solvents
Publication Date: 2003-Nov-05
The IP.com Prior Art Database
METHOD FOR DETECTION OF IMPURITIES IN SOLVENTS
Disclosed is a method to determine whether there is an impurity in a solvent. In the coatings industry, coating materials can be shipped in reusable containers, such as totes or drums. The reusable containers are washed between uses to prevent contamination in new products placed in the containers. Typically, the containers will receive a final rinse with a solvent. It is difficult to determine if the container is clean. Contamination from previous material in the container can cause defects, such as craters or "fish-eyes", in coatings formed from the material placed in a contaminated container. Silicone oils are a major cause of defects.
1. A test sample of 10 to 15 ml of solvent from the final rinse of the container is obtained and placed in a spectroscopically clean vial. An example of a vial is a WHEATON 25 ml scintillation vial with an aluminum lined cap.
2. A second vial is also provided that contains clean solvent of the same volume as a control.
3. Both vials are shaken.
4. The test sample is compared to the control sample for color, clarity, and particulates. If the test sample shows color, lacks clarity, and/or contains particulates, the container is sent for further cleaning.
5. If the test sample passes step 4, both vials are shaken vigorously together for 5-10 shakes.
6. The rate of disappearance of bubbles in the two samples is compared. Bubbles of all sizes should be considered when evaluating the samples....