Preparation Of Quick-drying Polyacrylic Sizing Agent

Sizing process is the extremely energy-consuming process during the processing of yarns into textiles.The thermal energy consumption is mainly concentrated on the agent preparation and drying.Researchers have conducted many studies on the high energy consumption of the sizing process,such as two highs and one low（low sizing viscosity,high sizing concentration,and high sizing force）technology,sizing drying technology etc.,and these studies have achieved significant energy savings.The medium and low temperature sizing technology has reduced the sizing heat energy,but the heat energy required for the drying process accounts for nearly 80%of the total energy consumption of the sizing yarn.Therefore,the study of quick-drying textile agent provides a new solution to reduce energy consumption.Based on the film-forming theory of polymer emulsion,a quick-drying polyacrylic agent was prepared by emulsion polymerization,and the synthesis process was optimized.The structure and performance of the sizing agent were tested systematically,and sizing yarns experiment was performed.The specific research work is as follows:Firstly,based on the analysis of the molecular structure of the three main sizing agents,it was found that starch and polyvinyl alcohol（PVA）contained a large number of hydroxyl groups,and the hydrogen bonds formed caused the presence of a part of the crystalline region and a large amount of bound water,so they were needed heating and drying slowly.The polyacrylic agent is an amorphous polymer material,with less hydrophilic functional groups,which weakens water binding capacity,and the particle diameter is the smallest,which is conducive to the formation of capillary effect and accelerate the aggregation of latex particles,so the film formation rate becomes faster,and polyacrylic agent is more suitable as a raw material for quick-drying sizing agent.Secondly,the subject uses monomer pre-emulsification and semi-continuous seed emulsion polymerization processes to prepare polyacrylic emulsion.During this process,methyl methacrylate（MMA）,methyl acrylate（MA）,ethyl acrylate（EA）,and methacrylic acid（MAA）were used as the main monomers,sodium dodecyl sulfate（SDS）and alkylphenol polyoxyethylene ether（OP-10）were used as emulsifier,ammonium persulfate（APS）was used as initiator,and sodium bicarbonate（Na HCO₃）was used as buffer.Through comparison of related properties,the best synthesis process for obtaining polyacrylic emulsion is:the monomer ratio of EA:MA:MMA:MA is 50:20:20:10,and the emulsifier ratio of OP-10:SDS is 3:1,the amount of is emulsifier 3.0%（relative to the total amount of monomers）,the amount of initiator is 0.35%（relative to the total amount of monomers）,the reaction temperature is 80℃,and the stirring speed is 200-300 r·min^-1.Thirdly,glycidyl methacrylate（GMA）was added during the emulsion polymerization,and a partially cross-linked structure was formed by the reaction between epoxy groups and carboxyl groups,so the quick-drying polyacrylic emulsion was prepared successfully.The copolymerization reaction of the monomer was verified by infrared spectroscopy.The quick-drying mechanism of the emulsion was summarized by analyzing the evaporation rate of water,the scanning electron microscopy,particle size distribution,and the contact angle of the film.With the increasing amount of cross-linking agent,the particle size of latex particles decreases gradually,making the area of interfacial evaporation increased,and the number of hydrophilic functional groups in the polymer reduces,which weakens the ability to bind with water,making the number of bound water decreased,finally the synergistic effect of the two accelerates the drying rate of the emulsion.Through testing glass transition temperature and agent performance,the amount of cross-linker is determined to be 5%（relative to the total amount of monomers）.Nextly,performance tests show that quick-drying polyacrylic emulsion has good stability,good adhesion to pure cotton roving and polyester/cotton roving,good miscibility with starch agent and PVA agent.The agent has good film formation and the film has excellent performance.It also can conform to the hairiness and the obtained sizing yarns have good performance,which can meet the requirements of warp weaving.Finally,the quick-drying polyacrylic sizing agent is applied to the sizing experiment.To achieve the same process moisture regain,the minimum drying time required for quick-drying polyacrylic agent is about 15%less than the time required for polyacrylic agent,which proves that it is easier to dry quickly,and it can be sized at room temperature,so the energy saving effect is significant.There are 28 graphs,17 tables and 72 references.