Changes of Free Formaldehyde Quantity in Non-iron Shirts by Washing and Storage

Abstract

Many non-iron shirts are finished with formaldehyde (HCHO) resin or HCHO vapor. Free HCHO in the non-iron shirt mostly decreases by washing. However, free HCHO sometimes increases once again with time by decomposition of resin. We have measured the quantity of free HCHO in 27 non-iron shirts and 3 regular shirts as control samples, before and after washing and drying, 1 week, 2 weeks, 1 month and 6 months after washing. Consequently, before washing, the quantity of free HCHO in 8 non-iron shirts was found to exceed 75ppm, max up to 202ppm. Seventy-five ppm is the standard value detected in underwears for adults according to the Law for the Control of Household Products Containing Harmful Substances. Even after washing, the quantity of free HCHO in 2 non-iron shirts did not fall below 75ppm. And after the storage for 6 months, the quantity of free HCHO in 7 non-iron shirts exceeded 75ppm. Six months after triple washing, the quantity of free HCHO in 5 non-iron shirts exceeded 75ppm. Our study revealed that the patterns of change in the quantity of free HCHO were dependent on the types of finishing.