| Waterborne acrylic resin has an important position in the field of waterborne coatings,because it has the advantages of easy film formation,good gloss and color retention,and environmentally friendly.Especially as coatings,it has excellent gloss,weather resistance,flexibility and other characteristics.However,the conventional acrylate coatings has some disadvantages,such as low hardness,poor water resistance,high viscosity,and poor corrosion resistance,which limit the application of water-based acrylate coatings.This paper conducts modification research on the above-mentioned problems.The main contents and conclusions of this paper are as follows:The aqueous hydroxy acrylic resin with a core-shell structure was obtained from methyl methacrylate(MMA),butyl acrylate(BA),methacrylic acid(MAA)and hydroxylpropyl acrylate(HPA)by semi-continuous solution and phase inversion emulsion polymerization.The structure,thermal stability,size and morphology of latex particles of the acrylate copolymer was characterized by fourier transform infrared spectroscopy(FT-IR),thermal gravimetric analysis(TGA),dynamic laser light scatter(DLS)instrument,transmission electron microscope(TEM)respectively.Moreover,the emulsifying performances and varnish film properties of aqueous hydroxy acrylic resin were discussed and the synthetic conditions were also optimized.The results showed that the hydroxy acrylic resin emulsion presents excellent stability and outstanding varnish film properties when the mass fraction of methacrylic acid was 6%,the mass fraction of hydroxypropyl acrylate was 10%,The copolymer emulsion particle could reach 119.8 nm,viscosity was 221.7 mPa·s,hydroxyl value was 43.2 mgKOH/g,the filming water resistance time could approach 40 h,the hardness was 53.4°,and the adhesion level was 1,the bonding strength of the prepared real stone paint was 0.97 MPa,and the temperature resistance was 36 times,Compared with the natural stone-like coatings adhesive currently used in industry,the main performance indicators are better than the natural stone-like coatings adhesive industry standard,which were better than the natural stone-like coatings adhesive industry standard.Based on the research of water-based hydroxy acrylic resin,a waterborne styrene-acrylic dispersion emulsion with core-shell structure was prepared by semi-continuous solution and phase inversion emulsion polymerization using methacrylic acid(MAA)as hydrophilic monomer,hydroxypropyl methacrylate(HPMA)as crosslinking monomer,styrene(St),methyl methacrylate(MMA)and butyl acrylate(BA)as monomers.Subsequently,the styrene-acrylic emulsion film was further prepared.The effects of the MAA core-shell mass ratio,the amount of monomers such as MAA,St and HPMA on the properties of waterborne styrene-acrylic dispersion emulsion and film were discussed.The structure and thermal stability of the emulsion film were characterized by FTIR and TGA.The size and morphology of the styrene-acrylic emulsion particles were characterized by DLS and TEM.The tested of the mechanical properties of the film has performed by mechanical experimental machine.The results showed that when the mass ratio of MAA in the core shell was 2:8,the mass fraction of MAA was 7.5%(based on the mass of all monomers,the same below),the mass fraction of HPMA was 10.0%,and the mass ratio of St to MMA was 3:1,the prepared copolymer emulsion had excellent properties,with a particle size of 259.65 nm,viscosity of 349.1 mPa·s,filming hardness of 72.4°,tensile strength of 1.422 MPa,and elongation at break 59.355%.The film water resistance time could approach 90 h,and the adhesion level was 1.Based on the research of styrene-acrylic resin,the phosphorylated styrene-acrylic antirust emulsion(PM-2-SP)with core-shell structure was synthesized by semi-continuous seeded emulsion polymerization using methacrylic acid(MAA)as hydrophilic monomer,hydroxypropyl methacrylate(HPMA)as crosslinking monomer,styrene(St)and methyl methacrylate(MMA)as hard monomer,butyl acrylate(BA)as soft monomer,2-hydroxyethyl methacrylate phosphate(PM-2)as functional monomer and dodecanethiol assegment regulator.The effects of PM-2 dosage on the stability of PM-2-SP emulsion,water resistance,electrochemical impedance and antirust properties of film were studied.The size and morphology of the PM-2-SP emulsion particles were characterized by DLS and TEM.The surface of the film was observed by AFM and SEM.The corrosion resistance of paint film was tested by salt spray tester.The results showed that when PM-2 dosage was 4%(based on the total mass of monomers,the same below),the prepared PM-2-SP emulsion had core-shell structure and exhibited good stability performance,which had a particle size of 135.7 nm and PDI of 0.150.The film had smooth and compact surface and excellent water resistance.Compared with those of pure styrene-acrylic paint film,the corrosion potential of the PM-2-SP paint film was-0.391 V,which was an improvement of 47.16%,while the corrosion current reached 1.95×10-7 A·cm2,decreased by 94.76%.The salt spray resistance test proved that the styrene-acrylic emulsion with core-shell structure had higher chelating density with metal ion than homopolymerized styrene-acrylic emulsion,and exhibited excellent antirust performance,and the salt spray resistance time reached 144 h. |
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