Preparation Of Hollow Styrene Acrylic Latex Particles And Its Structure Morphology And Opacity Ability

Hollow polymer latex particles have unique optical properties,covering performance,and the matrix of the coating binder material compatibility,low cost,low density,etc.dry stack,so the paint industry,the manufacture of ink,the paper coating,leather industry,catalyst supports,cosmetics industry and other fields has great potential applications,showing a great market value and advantages.At present,at home and abroad there are many methods reported in the literature for preparing hollow polymer latex particles,but most are not very mature,in which alkali-swellable emulsion polymerization and in situ polymerization of a non-solvent for the encapsulating mass production of the hollow polymer latex particles It has obvious potential,especially alkali swellable method.Procedure alkali swellable law first synthetic hydrophilic core layer,then coated with a hydrophobic shell hydrophilic core,and finally add alkali swelling that was hollow latex particles,namely the typical double-crosslinked alkali-swellable law.The use of double-crosslinked alkali-swellable polymer prepared by a hollow latex particles due to the low-rise,low intensity,easily collapse or rupture,and even reverse the formation of core-shell structure,it is necessary to develop new methods to compensate for the defect.In addition,the hollow polymer latex particles,there is no comprehensive academic study and explore the relationship between structure and morphology and its hiding between its influencing factors.However,due to the performance of the hollow polymer latex particles covered mainly by refraction of the light of the decision,and its light refraction and mainly it depends on its morphology,structure and morphology so hollow polymer latex particles on its cover performance decisive role.Therefore,it is necessary to cover the morphology and properties of the multilayer structure of the hollow polymer latex particles of a study to examine the role of specific factors that influence the relationship between them and,in particular,the layer thickness and the amount of the impact of cross-linking monomer,to provide technical reference for the preparation of large quantities of high cover of hollow polymer latex particles.Hollow polymer latex particles of the present paper is precisely in this context,is committed to research and development of simple preparation process has excellent covering properties,the focus around the three-crosslinked alkali-swellable Preparation of hollow polymer latex particles,layer influence of the thickness of the hollow polymer latex particle morphology and structure cover,affecting the amount of crosslinking monomers hollow polymer latex particle morphology and structure of hiding and encapsulation of non-situ polymerization solvent Preparation of hollow polymer latex particles,etc.four areas of expansion,specific work is as follows:(1)Preparation Method alkali swelling and characterization of hollow styrene-acrylic latex particles linked three-tier pay.Alkali swellable semi-continuous seed emulsion polymerization method,the use of layers of polymeric coating way,the first step in the preparation of a high carboxyl content core latex particles;the second step in the nuclear strong hydrophobic surface coating of latex particles,weak a hydrophilic intermediate layer;a third step in the surface of the intermediate layer is then coated with a hydrophobic shell completely;in the final stage of the preparation of alkali-swellable shell.To measure infrared and conversion experiments proved that the reaction proceeds as expected,the use of particle size and viscosity on the degree of swelling of the hollow latex particles were studied using scanning electron microscopy(SEM)and transmission electron microscopy(TEM)of the hollow polymer latex particles morphology were characterized,the acid value of the intermediate layer coating effect nuclear emulsion particles were measured by UV-visible spectrophotometer(UV-Vis spectrophotometry)hollow polymer latex particles hiding quantified.The results show that successfully prepared to give an average particle size of 350 ~ 750 nm,cavity size from 30 to 90%(volume fraction)of the hollow polymer latex particles,the emulsion solids content of about 31wt%.The degree of swelling of the hollow latex particles determines the smoothness of the surface,the interior cavity size,whether the latex particles collapse,rupture morphology;morphology hollow latex particles to determine their hiding,the more structured form,the fewer the number of latex particles rupture collapse which cover the better.Test results show that the acid value of the intermediate layer coated on the core of good,PDI value of a secondary reaction to the phenomenon of what has been effectively suppressed.Alkali swelling phase has an important influence on the shape of the hollow latex particles and hiding,with the increase of alkali-swellable stage,the degree of swelling of the hollow latex particles become smaller and smaller,collapse and rupture of the latex particles are less and less hollow latex particles after hiding first increased and then decreased,the best base swelling stage is 30 to 50% by shell stage.Theoretical glass transition temperature of the intermediate layer has an important influence on the shape of the hollow latex particles and hiding,as an intermediate layer theoretical glass transition temperature,the degree of swelling of the hollow latex particles become smaller and smaller,to reduce the fracture and collapse of the latex particles after the increase,the reduced hollow latex particles hiding first increase,the best theoretical glass transition temperature of the intermediate layer is 90 °C.(2)Study the thickness of the hollow polymer latex particle morphology and hiding rats.In the three-layer cross-linked alkali-swellable basis Preparation of hollow styrene-acrylic latex particles,a study of the intermediate layer thickness,affect shell thickness of the hollow polymer latex particle morphology and hiding properties.The results showed that the thickness of the intermediate layer has an important influence on the shape of hollow polymer latex particles and hiding,with the increase in the thickness of the intermediate layer,the degree of swelling of hollow polymer latex particles decreases,cracking and collapse of the latex particles gradually reduced,increasing the degree of surface smoothness,increased decreased after hiding first,when the intermediate layer / core = 8,the moderate degree of swelling of hollow polymer latex particles,hiding the best.Shell thickness has an important influence on the shape of hollow polymer latex particles and hiding,with the increase in the thickness of the shell,hollow polymer latex particles gradually reduce the surface roughness,cracking and collapse of the latex particles gradually reduced,hollow polymer latex after the first reinforcing particles hiding weakened shell / intermediate layer 7-9 packet review the optimum value.(3)Amount of the crosslinking monomer hollow polymer latex particle morphology and hiding rats.In the three-tier crosslinked alkali-swellable hollow styrene-acrylic latex particles were prepared on the basis of a case study in the amount of crosslinking monomer,core crosslinking monomer amount,the amount of crosslinking monomer is an intermediate layer of hollow polymer latex particle morphology and hiding in.The results show that with the increase of the amount of crosslinking monomers in the shell,the degree of swelling of hollow polymer latex particles decreases,the intensity gradually increased,the first decrease after hiding enhanced,optimal conditions for preparing hollow polymer latex particles is shell cross-linking monomer is used in an amount representing the total shell monomer 6wt%;alkali-swellable stage accounted for 30~50wt% of the total shell stage monomer system shell;crosslinking monomer is added in the entire nuclear core would severely condensate plastic,becomes solid,the reaction could not be continued.In the surface of the core is crosslinked to improve the hollow polymer latex particles hiding an important role,with the increase in the core surface crosslinking monomer amount,hollow polymer latex particles rupture and reduce the number of collapse,more and more smooth surface,hiding increases,but the amount of gel increased,the optimum amount of 1~3wt%.Intermediate layer was added crosslinking monomer in the latex particles cause swelling degree is too small,poor hiding,so the intermediate layer should be without crosslinking monomers.(4)The hollow polymer latex particles with uniform size and good monodispersity were made by in-situ polymerization with the method of encapsulation non-solvent with cross-linking modification,and the effect of cross-linking monomer(DVB)dosages in the shell on the synthesis process,morphology and opacity of the hollow polymer latex particles and its dry film were investigated by particle size analyzer,viscosity meter,acid value analysis,SEM,TEM and UV-Vis spectrophotometer,Differential scanning calorimetry.When the cross-linking monomer dosages of the shell were less than 15wt% of the total monomer dosages,with the reducing of the cross-linking monomer dosages in the shell,the strength trends of the shell of the hollow polymer latex particles decreased what resulted in the hollow polymer latex particles easily collapsed as well as a larger particle size distribution when the pore was swelling.When the dosages were greater than 20wt%,with the increasing of the cross-linking monomer dosages in the shell,the strength trends of the shell increased and the particle size trends of polymer latex particles decreased respectively what resulted in the swelling became difficultly.When the dosages were between 15~20wt%,with uniform particle size distribution,moderate shell strength and the preferably swelling property,the film obtained from the dry emulsion which contained the hollow polymer latex particles showed the optimal opacity performance.