磺酸盐型水性聚酯-丙烯酸树脂杂化体的合成研究

Synthesis of Sulfonated Waterborne Polyester-Acrylic Resin Hybrid

第一步先将间苯二甲酸-5-磺酸钠(5-SSIPA)和新戊二醇(NPG)投入到反应瓶中制得聚酯中间体;第二步将一定量的聚酯中间体与配方量的二元酸和二元醇投入到反应瓶中,并用椰子油酸对其进行改性,制备出酸值<5 mgKOH/g的水性不饱和聚酯;第三步,过氧化苯甲酰(BPO)作为自由基聚合的引发剂,将甲基丙烯酸甲酯(MMA)、丙烯酸(AA)、甲基丙烯酸-2-羟基乙酯(HEMA)接枝到不饱和聚酯上,制得聚酯丙烯酸树脂杂化体。选用国产水性多异氰酸酯作为固化剂,制成了水性双组分聚氨酯涂料。研究了5-SSIPA/NPG(物质的量比)对聚酯中间体的影响,5-SSIPA的用量对聚酯体系黏度及稳定性的影响,椰子油酸的用量,AA/5-SSIPA(质量比)对杂化体热贮存稳定性及涂料性能的影响,并考察了n(-NCO)/n(-OH)对涂料活化期及性能的影响。结果表明,使用合适的聚合工艺,5-SSIPA用量在8%~9%时,磺酸盐型水性聚酯-丙烯酸树脂杂化体有较好的水溶性,油度在8%~10%,AA/5-SSIPA=5%/8%时,杂化体的水分散体有较好的热贮存稳定性,n(-NCO)/n(-OH)=1.6~1.8时,漆膜表面状态良好,涂料活化期可达4 h以上,各项性能优异。

Firstly,the 5-sodium sulfonate isophthalic acid(5-SSIPA)and neopentyl glycol(NPG)are put into the reactor to prepare a polyester intermediate.Secondly,a certain amount of polyester intermediate,dibasic acid and glycol are put into the reactor followed by modication with the coconut oleic acid to prepare a waterborne unsaturated polyester with acid value lower than 5 mgKOH/g.Thirdly,a benzoyl peroxide(BPO)is used as the radical polymerization initiator to graft methyl methacrylate(MMA),acrylic acid(AA)and 2-hydroxyethyl methacrylate(HEMA)onto the prepared unsaturated polyester to form a polyester-acrylic resin hybrid.Finally,a domestic waterborne polyisocyanate is used as the curing agent to further prepare a waterborne 2K polyurethane coating.The effect of 5-SSIPA/NPG(mole ratio)on the polyester intermediates,the effect of 5-SSIPA dosage on the viscosity and stability of the polyester system,the effect of the coconut oleic acid dosage an AA/5-SSIPA(mass ratio)on the thermal storage stability and properties of coatings,and the effect of n(-NCO)/n(-OH)on the pot life and performance of the coatings are investigated.The results show that a suitable polymerization process when the amount of 5-SSIPA is 8%-9%can allow the sulfonate waterborne polyester to exhibit better water solubility with its oil length of 8%-10%.The aqueous dispersion of the hybrid has a better thermal storage stability at 5-SSIPA/AA=5%/8%.The coating has good properties with its pot life over 4h at n(-NCO)/n(-OH)=1.6-1.8.