Study On Synthesis And Properties Of Acrylic Emulsion With Core-shell Structure

The coating for exterior house with decorative features, protection and livability improvements, and construction of the most convenient, less expensive, the amount increasing each year. Poor dirt resistance and low aging impact the use of exterior house paint, latex paint performance important implications on dirt-resistant and anti-aging properties. Core-shell emulsion polymerization process can be "particle design" to improve the performance of emulsion. Acrylic emulsions are the most used in latex exterior paint, the test study on acrylic emulsion for the thesis, making use of pre-emulsification-semi-continuous seed emulsion polymerization process synthesized acrylic emulsion with core-shell structure. First, the ratio of hard and soft monomers and pre-emulsion preparation process was studied, following studied the core-shell structure on the properties of emulsion and coating properties. The results show that:①High power dispersion (mixing speed 2000r/min or ultrasound device) can reduce the amount of emulsifier in pre-emulsion, emulsifier reduced to 1.5%(OP-10:0.5%, SDS:1%);②Core-shell structure of hard-core soft-shell can effectively reduce the temperature of the emulsion forming film and enhance the composition of the MMA content to enhance the film's hardness; the ratio of core-shell thickness have a major impact on film of core-shell emulsion, when the ratio of core-shell less than 3:2, the emulsion with core-shell structure can not form film; the water absorption of the coating with core-shell increased with increasing BA's amount; core-shell structure has little effect on the emulsion viscosity.③Film's water absorption decreases first and then increased with the addition of AAc the appropriate amounts range is 1.5% to 3%; different distribution of AAc in core-shell structure and conventional structure can affect the viscosity of emulsion differently, the viscosity of core-shell latex emulsion is greater than the conventional when they have the same amount of AAc conditions.④Coating hardness is related to the MMA's content in the formula, and coating adhesion is related to the BA's concentration on the shell; the core-shell structure with hard-core and soft-shell can improve the MMA content in formula and increase the distribution of BA in the shell, so coating hardness and coating adhesion superior than the conventional structure emulsion.⑤Dirt-resistant properties of the coating is directly related to the film's water absorption, the higher water absorption of film the dirt-resistant properties of the coating is lower; the core-shell structure with hard-core and soft-shell has higher content of BA in shell that it increased the water absorption so the dirt resistance decreased; increasing MMA content in shell can help to improve the dirt resistance; the dirt resistance of the core-shell structure coatings was influenced by the ratio of hard and soft monomer in shell, composition for the core (MMA=60)/Shell (MMA=50, BA=40) has a higher dirt resistance than conventional homogeneous (MMA=90, BA=60); adding the acrylic wound take polar groups-COOH in, thus increasing the adsorption charge wound reduce dirt resistance coating.⑥Hard-core and soft-shell latex emulsion can improve the performance of emulsion changing to film and increase the ratio of hard monomer MMA monomer content, so it helped to improve the aging resistance of the coating, the higher content of MMA the better performance of the anti-aging; adding acrylic monomers in the shell coating is conducive to enhance the aging resistance, the aging resistance increased first and then decreased with the addition of acrylic, it has the best aging resistance when the acid is 2%.