Comparison of DMDHEU and Melamine-Formaldehyde as the Binding Agents for a Hydroxy-Functional Organophosphorus Flame Retarding Agent on Cotton

Abstract

It is necessary to use a crosslinking agent to bond a flameretarding hydroxy-functional organophosphorus oligomer (FR) to cotton so that the flame resistance of the treated cotton fabric can be durable to multiple homelaundering. Both dimethyloldihydroxyethyleneurea (DMDHEU) and melamine– formaldehyde (M-F) have been used as the binding agents between FR and cotton. The vertical flammability, limiting oxygen index (LOI) and phosphorus content after different numbers of laundering cycles as well as the wrinkle resistance and tensile strength of the cotton fabric treated with FR/DMDHEU and FR/M-F was investigated and compared in this research. We found that DMDHEU is more effective for crosslinking cotton cellulose and for crosslinking between FR and cotton than M-F. We also found that the bonding formed by DMDHEU between cotton and FR is more durable to multiple laundering cycles than that formed by M-F. M-F is a more effective nitrogen provider than DMDHEU to enhance the flame retarding performance of the treated cotton fabric through phosphorus–nitrogen synergism, therefore the presence of M-F in the flame retardant finishing system significantly increases the flame resistance of the treated fabric. DMDHEU, as an effective crosslinking agent for cotton, causes more fabric strength loss than M-F.

Effect of titanium dioxide on the flame‐retardant finishing of cotton fabric

“…It functions as a binder for FR and also as a nitrogen provider to enhance the FR performance of treated cotton fabric. 13,14 However, the molecular Moreover, the durability of the FR properties of the FR-treated cotton fabrics to multiple home launderings was also studied. Although the treated specimens burned and charred from 2.43 to 9.34 cm after one home laundering cycle, Table II shows that the specimens still passed the flammability test.…”

Flame‐retardant finishing in cotton fabrics using zinc oxide co‐catalyst

“…CL acts as nitrogen provider to enhance the flame retarding performance and forms a linkage between treated cotton cellulose and FR. 4,15 However, post-wet treatment breaks the weak linkage of incomplete esterification of cotton and thus the specimens are failed in the flammability test. However, crosslinking agent with proceeding to complete esterification of cotton is effective in reducing flammability of cotton fabric.…”

“…10,14 This is a consequence of increasing commercial demands in terms of cost-effectiveness coupled with increasing concerns for the environmental and general toxicological character of these materials, and treatments. 4,30 Formaldehyde is classified as a probable human carcinogen based on animal studies with neoplastic lesions at the point of contact, the respiratory tract, and limited evidence of human respiratory tract carcinogenicity. 31 Table IV shows the formaldehyde content existed on the fabric treated with different flame-retardant composition in accordance with Table I.…”

“…In the textile industry, flame resistance property commonly imparted to cotton fabrics by means of chemical finishing. 4 The use of flame retardant chemicals enables the treated fabrics to meet stringent safety standards and regulations. N-Methylol dimethylphosphonopropionamide (Pyrovatex CP New, FR) in combination with a bonding agent such as a melamine resin (KNITTEX CHN, CL) and a catalyst such as phosphoric acid (PA) has been one of the most commonly used durable flame retardant agents for cotton for many years.…”

“…In general, CL forms a linkage between treated cotton cellulose and FR, which functions as a binder for FR and also as nitrogen provider to enhance the flame retarding performance of the treated cotton fabric. 4,15 The carbonyls retained in cotton existed in three different forms, which are intermolecular ester linkage, carboxyl and carboxylate anion, when esterification occurs between PA and cotton.…”