| Tradition polyurethane curing agent is more than solvent-based that containsthe free NCO groups and solvents, caused harm to humans and the environment.With the human awareness of environmental protection, waterborne polyurethanecuring agent ensue. In this paper, a series of waterborne ployurethane curingagent(CA) were prepared, and the effect of the species of isocyanate, the type ofhydrophilic groups and the dosage of polyethylene glycol(PEG) on the performanceof the curing agent was investigated.Two types of hexamethylene diisocyanante curing agent(H-CA) andisophorone diisocyanante curing agent(I-CA) were synthesized by differentisocyanate raw materials, and were used to cure the same main agent of waterborneployurethane, respectively. Then two types of waterborne ployurethane adhesivenamed (H-WPU) and (I-WPU) were obtained, and we investigated the impact ofspecies of isocyanate on the properties of curing agent. The results showed that,curing time of H-WPU was significantly shorter than I-WPU in the same curingtemperature, and the curing time of H-WPU and I-WPU were80s and26srespectively when the curing temperature was80oC and dosage of CA was3%. Thepeel strength of WPU increased with the increase of the dosage of CA and curingtemperature. When the dosage of CA and curing temperature was in the samesituation, the peel stength of H-WPU was bigger than I-WPU. And while curingtemperature was60oC and CA was3%, the peel strength of H-WPU was0.219kN/mwhich reached maximum. The liquidity of WPU enhanced with the increase of thedosage of CA and the liquidity of H-WPU was evident poorer than I-WPU. Inaddition the onset decomposition temperature(Tonset) and the maximumdecomposition temperature(Tmax) of H-WPU were higher than I-WPU.The curing agent(D-CA) of anion dimethyopionic(DMPA), the curingagent(P6-CA) of non-ionic PEG600, the curing agent(P20-CA) of non-ionicPEG2000, the curing agent(D-P6-CA) of DMPA and PEG600hybrid, the curingagent(D-P20-CA) of DMPA and PEG2000hybrid were prepared. Then weinvestigated the impact of different waterborne monomer on the properties ofcuring agent. The results showed that, the viscosity of anion curing agent waslowest and the viscosity of non-ionic curing agent was largest, and the viscosity of curing agent of polyethylene glycol also enhanced. The curing time of waterbornepolyurethane adhesion reduced and the peel strength of WPU increased with theincrease of the dosage of CA and curing temperature. While curing temperature was60°C and CA was3%, the peel strength reached maximum. The liquidity of WPUimproved when the dosage of CA was increased, and the overall trend of theliquidity of WPU was V(D-WPU)<V(P6-WPU)<V(D-P6-WPU)<V(P20-WPU)<V(D-P20-WPU). Tonsetand Tmaxof the adhesive of waterborne polyurethane cured by different CA wereincreased when the dosage of CA was increased, furthermore.We prepared a series of waterborne ployurethane curing agent, whichsynthesized by HDI, trimethylol propane(TMP) and different dosage of PEG. Thenwe investigated the effect of mole rate of PEG600and TMP(nPEG600/nTMP) on theproperties of curing agent. The results showed that, when nPEG600/nTMPincreased,the emulsifying of curing agent and the viscosity of curing agent enhanced. WhilenPEG600/nTMPwas1.9, the viscosity was very large and the performance of curingagent was poor. The peel strength of the adhesive of waterborne polyurethane curedby different CA obviously increased. While nPEG600/nTMPwas1.6, the peel strengthwas0.171kN/m, which reached maximum. The minimum peel strength was0.114kN/m as nPEG600/nTMPwas1.9. |
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