三聚氰胺氰脲酸对环氧树脂封装材料的阻燃及增强研究

In order to overcome the disadvantages including the difficult dispersion of melamine cyanurate (MCA) in epoxy resin glue, deteriorated mechanical properties caused by stress concentration due to agglomerated MCA in resin, as well as introduced impurities by the traditional preparation process of the commercial MCA, a novel method combining synthesis and supermolecular structure control with efficient flame retardant/resin composition will be established in this project to prepare halogen-free flame retarded epoxy resin electronic packaging material. Melamine-cyanurate self-assembly reaction is conducted to synthesize MCA in a good solvent of epoxy resin, meanwhile, a small amount of charring modifier with stereo configuration is introduced to participate in the planar hydrogen-bond self- assembly. Accordingly, the planer growth rate of MCA hydrogen-bond net can be decreased and become lower than the longitudinal stack rate of the net. In this way, the ratio of length to diameter of the nascency MCA particle is adjustable and it can change the conventional MCA sheet morphology into fiber morphology. The above fiber MCA/solvent system is In-situ dispersed in the epoxy resin system. The viscous effect can effectively hold back the agglomeration of the dispersed nascency MCA particles, thus the well dispersed MCA/epoxy resin glue is obtained. Taking advantages of high rigidity and special fiber morphology, MCA can endow the material with both flame retardance and reinforced mechanical properties. This method is to realize the multifunction of the flame retardant, and high performance of addition type halogen-free flame retardant epoxy resin electronic packaging material.

针对添加型氮系阻燃剂三聚氰胺氰脲酸（MCA）阻燃环氧树脂电子封装材料制备过程中MCA在粘性树脂中分散困难，阻燃剂团粒产生应力集中劣化力学性能及传统MCA制备工艺引入杂质等缺点，本项目拟建立集MCA合成及超分子结构调控，阻燃剂/树脂高效混合分散为一体的无卤阻燃封装材料制备新方法。在环氧树脂良溶剂中进行三聚氰胺-氰脲酸氢键自组装合成MCA，同时引入少量立体构型成炭改性剂参与MCA平面自组装，利用其空间位阻抑制平面氢键网络生长，使网络横向扩展速率低于纵向堆叠速率（传统组装则相反），从而调控MCA初级粒子长径比，使其由传统片状转变为纤状形态；将纤状单分散MCA溶剂体系与环氧树脂预聚物就地混溶，利用树脂粘性有效阻止分散态MCA粒子聚集，获得高分散纤状MCA/环氧树脂封装胶料，利用MCA高刚性及纤状形态，在赋予材料阻燃性同时增强树脂基体，实现阻燃剂多功能化和添加型无卤阻燃环氧树脂电子封装材料高性能化。

电子封装材料正在国民经济及国防军工领域获得日益广泛应用，通过电子封装对于有效保护电子原器件、维持正常运行及延长其使用寿命具有重要意义。本项目设计了一种将MCA合成及其超分子结构调控，阻燃剂/树脂混合分散结合于一体的添加型阻燃环氧树脂基电子封装材料制备新方法。成功筛选出一种既能与环氧树脂任意比例混溶且又能实现MCA自组装合成的溶剂，首先在该介质中进行ME和CA自组装反应，同时在上述平面三嗪环分子自组装过程中引入少量具有立体分子构型的氢键复合改性剂，该改性剂分子通过自身氢键可与平面氢键网络结合参与到MCA超分子结构中，其立体分子构型所引起的空间位阻效应能抑制氢键网络平面生长，从而使MCA氢键网络纵向排列生长速度远大于平面扩展速度，形成初生态纤状MCA粒子，在获得纤状单分散态MCA悬浮液体系基础上，将液态环氧树脂胶（树脂预聚体）及辅料直接在上述体系中溶解和分散，制备得到分散性和均匀性良好的阻燃环氧封装胶液，最后脱除溶剂获得胶状无卤阻燃电子封装胶料。该方法可有效解决传统添加型MCA阻燃剂难以有效分散并由此导致的阻燃和力学性能劣化以及引入杂质的难题，实现了阻燃剂多功能化。研究表明纤状MCA作为一种高强高模填料对环氧树脂树脂基体具有较明显的增强效果。其流动性、电气绝缘性能、膨胀系数、耐热性、导热性、耐水性、密封性等综合材料性能指标均能满足电子封装材料的使用要求为无卤阻燃环氧树脂基电子封装材料低成本高性能化提供了一种新技术和新方法。