Synthesis And Application Of Reactive Nitrogen-phosphorus And Silicon Flame Rctardants For Silk Fabrics

The silk fabric belongs to flammable material because its limit oxygen index isonly about23%. So it can’t satisfy the flame retardant performance requirements ofsome markets. Now it also existed problems of poor washing fastness or easyyellowing when silk fabrics were finished by commercially flame retardant. Aiming atsolving these problems, two kinds of flame retardant with reactive groups weredesigned in this paper. Vinyl nitrogen-phosphorus flame retardants and vinyl sulfonecontaining silicon flame retardant were synthesized. Based on principles of graftcopolymerization between silk and vinyl and covalent bonding between silk and vinylsulfone reactive radicals, two kinds of self-made flame retardant were finished to silkfabrics, and the application performance of the fabric after finishing were tested.Two kinds of vinyl nitrogen-phosphorus flame retardants were synthesized withphosphorus oxychloride, diethylamine (or diisopropylamine), hydroxyl ethylmethacrylate as main raw materials, ethyl acetate as solvent and triethylamine as acidbinding agent. The synthesis of the target products were confirmed through fourierinfrared spectrum, hydrogen nuclear magnetic resonance spectrum and massspectrometry. The synthesis conditions of the intermediates and target product wereoptimized. Due to the grafting rate and limiting oxygen index of silk grafted by PN-2were higher than that of PN-1, so the paper selected PN-2flame retardant for furtherapplication. Then the effects of PN-2parameters on grafting rate of silk fabric wereinvestigated. And the LOI, washing fastness, physical and dyeing performance of thesilk fabric treated by PN-2were also tested. The results showed that the grafting ratewas15.4%and LOI was31.2%in the optimal grafting process conditions, reaching thenonflammable level B1. LOI was still30.9%after washing for50times, maintainingits good flame retardant properties. The whiteness of finishing silk was76.7, and therewas little difference with that of original silk（78.6）. But the breaking strength andmoisture regain rate were reduced by6.9%and9.8%, and the bending stiffnessincreased by23.3%compared with original silk fabrics. The K/S value respectivelydecreased by16.4%and10.9%with concentrations of3%reactive dyes and acid dyes, but these changes had little impact on the performance of the fabric.The vinyl sulfone containing silicon flame retardant was synthesized withsulphonation ester and KH-560as raw materials, DMF as solvent, and formic acid ascatalysis. Its structure was characterized by fourier infrared spectrum, hydrogennuclear magnetic resonance spectrum, mass spectrometry, proving the synthesis of thetarget product. Then the SiFR was treated to the silk fabrics. The results showed thatthe fixation rate of SiFR on silk fabric was49.7%, and the LOI could achieve27.3%in proper process conditions, reaching the nonflammable level B2. The LOI of silkfabric was still27.0%after washing for50times, keeping its good flame retardantperformance. Compared with the fabrics treated by PN-2, the decreasing rate ofwhiteness fell about0.1%, And the lower rate of breaking strength and moistureregain fell about0.9%and1.8%. Bending stiffness increase rate declined about4.1%and K/S value by reactive dyeing reduced about5.5%lower rate. But the acid dyeK/S value increased by11.7%compared with the original silk fabric.The final study showed that: the flame retardant performance treated by PN-2was better than SiFR, and both had good washing fastness performance. But SiFRwas better than PN-2in some physical and dyeing properties, such as whiteness,breaking strength, moisture regain, and bending stiffness.