Study On Anhydrous Silicone-paraffin Finishing Agent For High-speed Sewing Thread

With the rapid increase of the sewing machine speed,the problems of conventional polyester sewing threads due to the obstruction of pinhole by fiber melting and the increase of breakage are becoming more and more serious,which cannot meet the requirements of high-speed sewing.Adding post-finishing lubricant is an effective method to improve the friction resistance of sewing threads,and silicone-paraffin finishing agent is currently recognized in the field of sewing threads to effectively improve the quality of sewing threads.Silicone-paraffin finishing agents have the advantages of excellent lubrication effect,lower oil content and oil leakage,etc.However,the new high-quality silicone-paraffin finishing agents rely on imports in a great extent and are expensive.For this reason,based on the related knowledge of surfactants and organic concept map,this subject independently developed a silicone-paraffin finishing agent with good lubricity and high bonding fastness to polyester substrate,in-depth research on the mechanism of surfactants in silicon/paraffin system and the inherent law of improving the bonding effect of silicone-paraffin film on polyester substrate.The main research work and results are as follows:First,the basic physical and chemical properties of silicone oil and paraffin were studied,including the physiological inertness,thermal shielding properties and lubricating properties of silicone oil,the film-forming properties and lubricating properties of paraffin.A binary system of anhydrous silicone-paraffin emulsion with maximum compatibility was prepared by studying the compatibility of paraffin of different melting points with silicone oils of different viscosities,the storage stability of the binary system and the bonding situation between the silicone-paraffin film and the polyester substrate were studied.The results show that within limits,the lower the melting points of solid paraffin,the higher the maximum compatibility with simethicone;the lower the viscosity of simethicone,the higher the maximum compatibility with solid paraffin;Without the addition of surfactants,the silicone-paraffin binary system is poor in storage stability,film-forming properties,and the fastness of the silicone-paraffin film to the substrate,which cannot meet the application requirements.Then,through the optimization of the required components of the anhydrous silicone-paraffin emulsion,the distribution ratio of composition of the emulsion and the research of emulsification process,the subject developed an anhydrous silicone-paraffin emulsion with excellent storage stability,heating stability and low particle,furthermore established the mechanism of surfactants in the system and the model of surfactants.The results show that:A compound surfactant R composed of R1 in a linear structure and R2 in a bifurcated structure is suitable for a silicone/paraffin anhydrous emulsification system;the optimized formula and preparation process of high-temperature silicone-paraffin finishing agent are:89%1000CS simethicone,5.5%No.46 solid paraffin,5.5%the compound surfactant R,emulsification by agent-in-oil method,an emulsification temperature of 80?,an emulsification speed of 4000 r/min,and an emulsification time of 20 min;the optimized formula and preparation process of normal-temperature silicone-paraffin finishing agent are:90.8%500CS simethicone,3.5%high-viscosity liquid paraffin,1.2%No.58 solid paraffin,4.5%compound surfactant R;emulsification by agent-in-oil method,the emulsification is done in two steps,the first emulsification speed is 4000r/min,emulsification temperature is 80?,emulsification time is 40 min,the second emulsification speed is 1500 r/min,the emulsification time is 20 min,the temperature of emulsion dropped in a water bath while the second emulsification;the high-temperature and normal-temperature anhydrous silicone-paraffin emulsions prepared under the above-mentioned formula and process have good storage stability,and the application effect is obviously superior to conventional silicone oil finishing agents.Finally,the performance of the sewing thread prepared under the optimized formula and process,including friction coefficient,yarn hairiness and color variation,was studied.The internal law of the interaction between silicon-paraffin film and polyester substrate is analyzed and discussed.The results show that the silicone-paraffin finishing agent(the type of high-temperature and normal-temperature)prepared under the optimized process can significantly improve the friction resistance of polyester sewing threads,reduce hairiness and breakage,the comprehensive performance is basically consistent with the performance of the target product.The multi-component silicone-paraffin system has low interfacial tension and is rich in ester groups,carboxyl groups and other groups with good structural similarity to polyester fibers,which enables it to be "implanted" in the polyester substrate and increase the contact area between the silicon-paraffin film and the substrate,And increase the intermolecular force between the film layer and the fiber,thereby improving the binding fastness of the silicon-paraffin film to the polyester substrate.