| Polyvinyl acetate(PVAc) adhesive is widely used in cigarette, but with the development of technology in the cigarette, the tack, viscosity, and size of particle of it can not meet the requirement of cigarette. This study synthesizes a kind of high speed cigarette adhesive with high tack and suitable viscosity with using acrylate to monomer modify PVAc, and composite emulsifier and initiator were used in this experiment.This study adopting the core-shell emulsion polymerization and pre-emulsification The core of emulsion particle consists of seed and outer core. The materials of seed and outer core include the same proportion of VA c and Butyl acrylate(BA), And adding AA in the seed core. Materials of shell are comprised of VAC, BA and 2-Ethylhexyl acrylate(2-EHA).Study on the effects of soft and hard monomers on MFT, viscosity, and tack of emulsion. Experiment indicates that the MFT decreases and the tack increases with vinyl acetate modified by BA. But the decrease of hard monomer will reduce the cohesion and holding power of emulsion that will limit the increase of tack. Using 2-EHA gradually replace BA in the shell further reduce glass transition temperature of the shell and make tack of emulsion increasing from 11# to 18#.with the stable holding power. And this study also inquiry the influences of acrylic acid(AA) dosage on the properties of emulsion, the stability of the emulsion can be improved by the increase of AA. When the ratio of VAC, BA, and 2-EHA is 15:3:2, VAC, BA in the proportion of seed nucleus, outer core and shell were 3:9:8 and 1:3:2, the amount of AA is 0.5% in monomer dosage, the tack increased from 8# to 16#, the MFT decrease and the stability of emulsion increase. This study also makes orthogonal experiment for the interaction between the monomers and it ultimately determines the amount of monomers.The study explored the effects of the ratio of SDS and AEO-9 and dosage of emulsifier on the properties of emulsion. The study shows that the freeze-thaw of emulsion will decrease with too many SDS. When the ratio of AEO-9 and SDS is 2.0:1, the amount of emulsifier is 2.5%, the emulsion has best performance. With proper proportion of SDS and AEO-9, the smaller of emulsion particle size the more of emulsifier.The experiment discussed the influence of ratio and dosage of initiator on performance of emulsion. The amount of residual monomer in emulsion polymerization is minimum when the proportion of sodium bisulfite with potassium persulfate(K2S2O8) is 1:8. When initiator is 0.9% in monomer dosage, the emulsion has best film, volume average particle size is 1.617 ?m, and the emulsion has best performance.Study on the effects of PVA content on the performance of emulsion. The results of experiment show that the PVA was in favor of the mechanical stability of emulsion, but excessive will cause poor freeze-thaw stability. With the increase of PVA-1788, the viscosity and tack of emulsion increase. The performances of emulsion meet the requirements for high-speed cigarette machine when the amount of PVA is 4.5%.The theology of emulsion is adjusted by polyurethane type nonionic associative. And the ratio of viscosity changes between 3 rpm and 30 rpm is 5% when dosage of TRM-004 is 1%~1.5%.The molecular structure of polymer was characterized through Fourier Transform Infrared Spectroscopy(FTIR), and the results show that the monomer has been involved in the reaction fully. By scanning electron microscopy we can see that the particle is uniform sphere. By Transmission electron microscopy we can see that the structure of particle core-shell and DSC diagram shows that the MFT of shell is-8.57 ? and the MFT of core is 38.70 ?.And by the minimum film-forming temperature tester we can see that the MFT of the emulsion below 7.5?. |
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