Study On Synthesis And Performance Of Room Temperature Self Cross Linking Acrylic Resin Emulsion And Film

The acrylic resin is a kind of popular leather finishing agent material in theworld. In terms of the cost, process, and combination property, acrylic resin hasmore advantages than others. However, its main flaw is sticky when heated andfragile when cooled, making its weather resistance poor. In this thesis, wesynthesized a series of room temperature self-crosslinking acrylic resin emulsionby seed-emulsion polymerization and studied the effect of different parameter ontheir coatings physical or chemical properties. We hoped to provid technicalideas for the preparation of new leather finishing agents.At the beginning, we used methyl acrylate, methyl acrylate, butyl acrylateand functional monomer (DAAM/AAEM/GMA) as basic momotors to study thepolymerization process, conditions, effect of emulsifier or initiator on acrylicresin emulsion. The results showed that: firstly, pre-emulsification was carriedout by the basic monomers; secondly, we synthesized emulsion through seedemulsion method. The optimal parameters was obtained as follows: Tg ofpolymer was-30℃; mass proportion between monomer and water was4:6;complex emulsifying agent was mixed of AES and OS-15(mAES：mOS-15=2:1),whose dosage was about3%of monomer dosages, while initiator (APS) wasabout0.5%; pre-emulsion temperature was45°C, stir speed was630r/min; thereaction temperature was85°C, stir speed was500-600r/min; the stir speed ofpre-emulsification and seed formation was rapid and gradually slowed downlater in the reaction.Room temperature self-crosslinking acrylic resin emulsion was synthesizedby introducing functional monomers such as DAAM, AAEM or GMA andadding ADH or HDA as crosslinkers. The effect of the three crosslinkingsystems on the performance of acrylic emulsion film were investigated by usingof DSC, hardness, solvent swelling experiment, mechanical properties analysisand so on. The results showed that: because of three crosslinking systems,24hwater absorption of film decreased from34%to at least18.7%and the solubility in THF decreased to at least37.2%; the hardness improved; the Tg ofDAAM-ADH or GMA-HDA included film HDA grown up; the elongation atbreak and breaking strength both changed after introducing three kinds ofcrosslinking systems. DAAM-ADH film showed it hard and strong whileAAEM-HDA and GMA-HDA film showed them strong and tough. So,DAAM-ADH film is suitable for top coating, while AAEM-HDA film for basecoating.A series of ambient temperature self-crosslinking acrylic resin emulsionswere synthesized by introducing a functional monomer acetyl acetyethylmethacrylate (AAEM) and adding a protein material (such as gelatin, casein, andalbumen powder) into the acrylic resin emulsion as a crosslinking agent. Thepaper studied the impacts of three protein crosslinking agents on the basicfilm-forming performances of the acrylic resin emulsion by using the hardness,water absorption, solvent resistance, tensile strength, elongation at break andglass transition temperature (Tg) and the like properties of the film as indexes.The experimental result showed that: in the three crosslinking systems, the waterabsorptions of the films took on increasing tendencies of different degrees withthe increase of crosslinking degree, the water absorptions on24hour weretended to be conformance, but all the water absorptions were higher than that ofthe acrylic resin film without crosslinking; the hardness and tensile strength ofthe film gradually increased, specifically the hardness of the film crosslinkedwith gelatin and the tensile strength of the film crosslinked with casein were thehighest; the elongations at break were in gradually reducing tendency; thesolvent resistance of the film crosslinked with gelatin was the best; the impact ofalbumen powder crosslinking on the elongation at break was not great and wasbasically in the range of600%to700%; and the infusion of the protein-AAEMcrosslinking system would significantly improve the Tg of the acrylic resinemulsion film, but the Tgs of the films crosslinked with the three proteincrosslinking agents were basically approximate.