| As one kind of Functional Materials, Water dispersible polyurethane has been used in awide range of fields, such as coating, adhesive, ink, biological materials, building materials,automotive, textile, etc. By virtue of its excellent application performance, water dispersiblepolyurethane has gotten more and more attention from all over the world. Having obviousadvantages in transport, storage and environmental protection compared with oil-basedpolyurethane, water dispersible polyurethane take water as the dispersion medium. The mostwidely used methods are acetone process and prepolymer process. Acetone process has solarge amount of organic solvent to be used that make the cost of production go up and reduceproduction efficiency and security. Although a small amount of organic solvent was used inprepolymer process compare to acetone process, chain extension carried out innon-homogeneous system, which will bring about difficult to control the degree of chainextension. Finally, poor reproducibility will appear in results. As one of the most importantapplications, the research of water-borne polyurethane dispersion adhesive tends tohighperformance and environmental protection at home and abroad. A series of water-bornepolyurethane dispersion adhesive which used in composit films, paper and plastic, PVCsubstrate have been developed. At present low solid content, small initial peel strength andT-peel strength, poor heat resistance are the mean problems which can be found inwater-borne polyurethane dispersion adhesive.In this paper, polyurethane ionomer was synthesized by poly(1,4-butylene adipate glycol)(PBA) as soft segments,1,4-butanediol (BD) and isophorone diisocyanate(IPDI) as hardsegments, polyether diol containing sulfonate(SPPG) as hydrophilic monomer in soft segmentand dibutyltin dilaurate (DBTDL) as catalysts through the method of bulk polymerization.Polyurethane dispersions (PUDs) adhesive with a solid content of50%were synthesized bygranulation, dissolution in acetone, dispersion in water, distillation of acetone ofpolymerization, and the whole process called pellet process. In further study, this pelletprocess conducted by a twin screw extruder with the shape of a reactor to achieve continuouspellet process, and its outstanding advantages are efficient and energy saving. As statedpreviously, pellet process has many virtues, such as high production efficiency, storagestability, cost savings, high utilization rate of solvent recovery, ect. Water-borne polyurethanedispersion adhesive which prepared by pellet process can overcome the above shortcomingsin part.The properties of PUDs were measured by Laser particle size analyzer, TEM analysis and Brookfield viscosity. The hard segment content(HSC, wt%), hydrophilic group content(HGC), and total NCO/OH molar ratio(R) effect on particle size, distribution of the PUD, themorphology of dispersions and the viscosity changes in different state were researched. Theproperties of PUD films were surveyed by Dynamic mechanical analysis (DMA),Thermogravimetry analysis(TG) and tensile tests. The hard segment content(HSC, wt%),hydrophilic group content (HGC), and total NCO/OH molar ratio(R) effect on glass transitiontemperatures(Tg), the degree of phase separation, decomposition temperature and Mechanicalproperties were researched. Initial peel strength, T-peel strength and heat resistance wereinvestigated by Peel strength test (PVC/PVC). A maximum initial peel strength value of6N/mm and T-peel strength value of10N/mm are obtained, and show excellent heat resistanceperformance. Water-borne polyurethane dispersion adhesive which obtained by this paper canbe applied to shoe adhesives, laminating adhesive of packaging materials, automotive interiormaterials adhesive, glass fiber cluster adhesive, ect. The performances of the product reachthe product obtained by the traditional methods.\... |
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