[Transparency test for plastic containers].

Abstract

A new sensory test method for judging the transparency of plastics containers for aqueous infusion was developed. The test procedure is as follows: Prepare four different grades of reference suspensions, grade 1 to 4, according to the procedure in ISO/DIS 3826. 4. Take ten empty containers. Fill two containers with the grade 1 suspension, two with the grade 2, and so on, filling 8 containers in all. Fill the remain 2 containers with water. Show each one of the ten containers to a volunteer in random order and ask him each time how does he judge it, turbid or not turbid. Repeat these tests among five different volunteers. If all volunteers judged the containers filled with the most turbid reference suspension, grade 4, to be turbid and the similar containers filled with water not turbid, such containers were judged to be transparent. On the other hand, the containers were not considered to be transparent if a significant number of volunteers judged even the containers filled with grade 4 suspension to not be turbid and vice versa. The test accurately determines the difference in the transparency of containers.