| At present, there are solvent-based, water-based adhesives and solvent-free adhesive in the adhesive field. The composite packaging materials commonly used to use polyurethane adhesive with ethyl acetate as the solvent, but the ester-soluble polyurethane has some toxicity and strong irritant and cause great harm to humans and the environment. Compared to ester-soluble one, waterborne polyurethane has good environmental performance, but there will be more or less the isocyanate groups exited in highly toxic free aromatic isocyanate molecules such as TDI, MDI etc. Meanwhile, water volatile slowly, which impact on productivity, and waterborne adhesive has poor adaptability in materials such as plastic, aluminum foil. Hot melt adhesive without solvents cost too large in equipment investment, so it is difficult to develop in the near future. With the improvement of the market for flexible packaging raw materials security performance requirements, the alcohol-soluble polyurethane adhesive came into being. In this topic, ethanol-soluble polyurethanes were prepared, which balance water-based adhesives and solvent-based adhesive, and has a great advantage in cost savings.The first chapter introduces the polyurethane adhesive materials selection and classification of the main factors affecting the bonding strength, and alcohol-soluble polyurethane adhesives and other types of polyurethane adhesives for performance comparison, highlighting its advantages; introduced grate The mechanism of sesame oil modified polyurethane, nano-materials-modified polyurethane, epoxy-modified polyurethane, the use of experimental methods and research status.The second chapter introduces castor oil part instead of the polyester(ether) polyol synthesis of alcohol-soluble polyurethane resin, infrared analysis showed that castor oil reaction with the polyurethane, the polyurethane into three-dimensional structure from a linear molecular chain, castor oil added, making The peel strength of the polyurethane adhesive has been markedly improved, but the addition of more than7.5wt%, the increase in peel strength of the sample is smaller, its tensile strength increases first and then gradually smaller, while the elongation at break decreasing; polyurethane soft and hard section of the highest weight loss temperatures increase; comprehensive comparison, adding10wt%of the samples has greatly improved the traditional characteristics of the polyurethane, you can get good performance of the alcohol-soluble polyurethane resin.The third chapter is still the castor oil a partial substitute for the preparation of polyether polyols N210alcohol-soluble prepolymer of organosiloxane (KH550) to act as organic-inorganic network coupling agents, surface modification of nano-silica, hydrophobic nano-silica particles are prepared, in the mechanical agitation and ultrasonic field dispersed into the polyurethane solution, the results show that:With the increasing of the nano-silica content, viscosity, slow growth, the tensile strength has increases, while the breaking elongation, lower water absorption of PU film. When the nano-silica content continue to increase the hardness and peel strength have declined. Comprehensive comparison, adding2wt%of the samples is very well.The fourth chapter introduces the original preparation of nano-silica modified polyurethane base, propionic acid is involved in ring opening reaction of epoxy ring opening initiator, the hydroxyl groups makes the epoxy groups of open-loop, the introduction of the polyurethane matrix. The results showed that:the introduction of epoxy to add the amount of SiO2-composites the tensile strength increased, fracture elongation declined, the hardness has been an upward trend; adding8wt%of epoxy resin After the hard segment weight loss temperatures from344℃to356℃, the soft segment weight loss temperature increased from389℃to391℃; On this basis, the introduction of2wt%of nano-SiO2, the hard segment weight loss temperatures from356℃to363℃, the soft segment of maximum weight loss temperature increased from391℃to394℃. The heat-resistant properties of the material is well. |
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