| The vinegar-acrylic emulsion is a water-based emulsion polymer,which has the characteristics of low cost,environmental protection,non-toxic,and easy operation.It is often used in cigarette adhesive.However,the cigarette adhesive has been unable to meet the requirements in viscosity,rheological properties and adhesive properties due to the increasing speed of cigarette machine.Therefore,it has certain theoretical value and practical significance to develop a new type of acrylic acetate emulsion synthesis technology and a new type of adhesive suitable for high speed cigarette adhesive.In this paper,the synthesis and application properties of core-shell acetate acrylic emulsion were studied.A core-shell polymerization technology is selected to synthesize a vinegar-acrylic emulsion with a core-shell structure.The monomers are vinyl acetate(VAc),butyl acrylate(BA)and acrylic acid(AA).The properties and particle structures of the emulsion were characterized by rotational viscometer,rotational rheometer,DLS,SEM and TEM.Firstly,the preparation and properties of core-shell acetate acrylic emulsion were studied.The effects of polymerization process,monomer ratio and dosage,emulsifier ratio and dosage,initiator dosage,protective colloid,and other process conditions on the performance of vinegar-acrylic emulsion were mainly investigated.The results showed that compared with the single seed emulsion polymerization process,the gel rate of the emulsion decreased from5.9%to 2.7%by using the pre-emulsification-seed emulsion polymerization process.When BA/VAc was 1:2,the minimum film forming temperature reached the lowest value of 3.24?,the tack is increased from 9~#to 12~#,and when the amount of AA added is 2.0wt%of the total monomer mass,the water absorption rate is reduced from 22.80%to 18.13%,and the water resistance of the emulsion is improved.As the mass ratio of secondary alcohol polyoxyethylene ether(S-90)and sodium dodecyl sulfate(K-12)gradually decreased,the stability of the emulsion gradually decreased.When the composite emulsifier S-90/K-12 is3:1,the viscosity is 2200m Pa·S,and the amount of emulsifier is 2.5wt%of the mass of the total monomer,the particle size and distribution of the emulsion are the best.The particle size is 1036nm and the dispersion is 0.353.When the amount of initiator is 0.87wt%of the total monomer,the content of residual monomer reaches the requirement,and the initial viscosity reaches 11~#.The amount of protective colloid should not be too much.When the polyvinyl alcohol accounts for 4.9wt%of the total monomer,the polymerization process is stable,the viscosity is 3200m Pa·s and the initial viscosity is 11~#.Other technological conditions were optimized.When the reaction temperature of seed stage was 75?,the holding time of seed stage and shell stage was 1h,and the stirring speed was 180r/min,the viscosity of emulsion was 3160m Pa·s.Finally,the synthesized emulsion was characterized by FT-IR,SEM,TEM and DSC.It was proved that the P(VAc-BA-AA)emulsion with core-shell structure and uniform spherical particles was synthesized.Secondly,the scale-up experiment of core-shell type vinegar-acrylic emulsion and the compound application experiment of high-speed mouthpiece glue for cigarettes are studied.The influence of factors such as the type and dosage of the added emulsion product on the performance of the composite high-speed nozzle adhesive for cigarettes was focused on,and a suitable high-speed nozzle adhesive compound formula for cigarettes was determined.The results showed that the amplification process and the formula were stable,and the properties of the synthesized acrylic acetate emulsion were basically consistent with the sample.Vinyl acetate-acrylic emulsion was compounded and modified by three different finished emulsions,and the preferred modified emulsion was DA141.When the content of DA141 emulsion was15wt%,the initial viscosity of the compound nozzle adhesive was 12~#,and the high-speed shear rheological property was closest to the sample,which met the requirements. |
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