Release of formaldehyde and melamine from tableware made of melamine — formaldehyde resin

Abstract

The relationship between the concentrations of formaldehyde and melamine released into 4% acetic acid from dishes and bowls made of melamine‐formaldehyde resin was determined. The average concentrations in the migration solution after the sample had been treated at 60, 80, and 95 °C for 30 min with 4% acetic acid were 0.0 ± 0.1, 0.5 ± 0.4 and 3.0 ± 2.2 ppm, respectively for formaldehyde and 0.04 ± 0.07, 0.21 ± 0.20 and 1.19 ± 1.18ppm, respectively for melamine. The correlation between the concentrations of formaldehyde and melamine released at 95 °C was y = 0.4858x ‐ 0.2724 (r = 0.8860), where y is melamine concentration (ppm), x is formaldehyde concentration (ppm) and r is the correlation coefficient. The molar concentration ratios of formaldehyde to melamine (F/M ratio) were 15.4 ± 11.6 at 80 °C and 14.9 ± 10.1 at 95 °C. Hence the release of both migrants was affected by temperature but the F/M ratio was not affected. The release of both compounds was increased on repetition of the migration test at 95 °C but their concentrations remained constant after the tenth and seventeenth repetitions of the treatment. During this period, the F/M ratio decreased according to the equation In y = – 1.4344 In x + 3.7814 (r = ‐ 0.9984) for a sample before the tenth repetition of the treatment and remained between 1.7 and 1.9 after the twelfth repetition, where y is the F/M ratio and x is the number of repetitions of the treatment.