Application Of Microcapsule Technology In Curing Agent And Liquid Crystal

Microcapsules have advantages of improving physical reaction and the physicalproperties of the active material (such as: liquid is changed into a solid state, goodseparation state etc) making material has latent and reduce toxic damage to theenvironment and are widely used in industrial products.The curing agent microcapsules which are used in coating substrate can lead thecoating has the latent. As the polymerization reaction can be slowly happen betweencuring agent and coating matrix at room temperature, which will reduces the storagelife of the paint. Microencapsulation of the curing agent can make curing agent andcoating matrix isolation, only under certain temperature and pressure, the micro-capsules are ruptured and release agent then react with coating substrates. Therefore,microencapsulation of curing agents can make one-package products possible.Because of the special physical and chemical properties of liquid crystal, whichis widely used in liquid crystal device. Among which, polymer dispersed liquid crystal(PDLC) don’t need a polaroid and light source, and the preparation technology issimple, so PDLC is widely used in flexible display device of large size, grating,electronic curtain and electronic paper, etc. The preparation technology ofmicroencapsulation is simple and controllable, which become one of the importantpreparation methods of PDLC.Firstly, the solvent evaporation method with polymethyl methacrylate (PMMA)as wall material and the in situ polymerization method with methyl methacrylate(MMA) as the wall material were uesed respectively to prepare the curing agent(TGIC) microcapsules which canbe used in paint in this paper. By analyzing anddiscussing the particle size and size distribution, morphology and composition of themicrocapsules, the optimizing process conditions of microcapsules was determined.The results of experiment showed that the above two methods can prepare curingagent microcapsules effectively and the process did not destroy the property of TGIC.On this basis, by reducing volume ratio of continuous phase stationary phase,changing the stirring speed, emulsifying, etc. We explored the amplificationpreparation of curing agent microcapsules by solvent evaporation techniques; Byenlarging the process step-by-step, a production condition of1L scale waspreliminarily established.Secondly, the release performance, thermal performance, curing performance andmechanical performance of TGIC microcapsule were analyzed and discussed. UV-thermal dual curing resin was used as matrix, and the feasibility application of PMMA/TGIC microcapsules for UV-thermal dual curing resin was also analyzed.The results of the experiment showed that the microcapsules prepared by above twomethods have better compatibility with resin matrix, very good stability at roomtemperature, good release performance and mechanical performance. Pencil hardnessof cured coatings can be up to6H and adhesive can reach level1.Finally, nematic phase liquid microcapsule was prepared by the in situpolymerization method using the urea-formaldehyde resin (U-F) as wall material. Byanalyzing and discussed the particle size and size distribution, morphology, theencapsulation efficiency and core loading of microcapsule, technology conditions ofpreparing the microcapsule are optimized, including reaction temperature, stirringspeed, etc. The results of the experiment showed that the average size ofmicrocapsules prepared by this method was about5μm and narrow distribution wasobtained, and the optical properties of liquid crystal was not destroyed by thismicroencapsulated processes.