Abstract:

HDI biuret particles coated with hydroxyl polyacrylic resin were prepared by using phase inversion technique. The film formation process of the coated particles was tracked by FTIR and the coating retention rate soaked in solvent. Effect of mixing technology，hydroxyl monomers and catalyst on the crosslinking degree of coating was investigated. During the film formation process，urethane crosslinking is formed by reaction between —OH and —NCO. —NCO also reacts with H₂O and the produced CO₂ can escape from the coating film without forming film defects. As the increase in film formation temperature，the higher cross-linking degree of the coating at earlier stage，the lower crosslinking degree of the coating at later stage. The crosslinking degree of film can be increased by improving the dispersion of HDI biuret in hydroxyl polyacrylic resin and HDI biuret due to the increased hydroxyl reactivity of polyacrylic resin. The crosslinking degree of film can also be increased by the increase in catalyst content.

摘要：

采用相反转法制备了羟基丙烯酸树脂包覆HDI缩二脲乳液，通过FTIR和涂膜溶剂浸泡保留率跟踪了包覆粒子的成膜过程，考察了混合工艺、羟基单体种类、催化剂等因素对涂膜交联的影响。结果表明，成膜过程中，—OH和—NCO交联生成氨基甲酸酯，—NCO同时与H₂O反应生成的CO₂扩散出涂膜，没有形成涂膜缺陷。成膜温度越高，涂膜交联度在成膜前期越高，而在成膜后期，涂膜交联度反而越低。HDI缩二脲在羟基丙烯酸溶液中分散越均匀，羟基丙烯酸树脂中羟基反应活性越高，催化剂用量越多，涂膜交联度越大。