Study On Synthesis Of Novel Benzoxazine And Application In PCB

This article covers the special request according to the area of the printed circuit board (PCB) with lead-free which the substrate resin proposed, and benzoxazine with the outstanding heat-resistant performance, fire-retarding performance, mechanics performance and electrics performance, than circumfuses the copper clad laminate to substrate resin high glass transition temperature (Tg), the high thermal decomposition temperature (Td) this research subject. It is for the purpose of enhancing Tg and Td of polybenzoxazine, satisfying to technologic request of the copper clad laminate thermo-compression, at the same time, the obtained resin has the good general performances. Thus several kinds of benzoxazine based on poly-ring were synthesized and thermo-compressed to laminate.According to the flexibility of molecular design of benzoxazine and the knowledge which studied in the polymer chemistry, benzoxazine monomer (BPF4-BOZ) which prepared with bisphenol formaldehyde (BPF),formaldehyde and diaminodiphenyl methane (MDA) as raw material, toluene,ethanol as solvent, phenol as blocker was designed and synthesized. Then, the other two benzoxazine monomers BPF6-BOZ which changed raw material ratio and BPA-4BOZ which changed structure and chose different bisphenol (Bisphenol A) were synthesized. The structure of benzoxazine monomer was studied by FTIR and ~1H NMR. The molecular weight and its distributeon was investigated by GPC.The curing reaction of a series of systems was investigated by DSC and gel time test. Under the gel time test, the activation energy (Ea) of BPF4-BOZ and BPF6-BOZ extremely to approach, respectively was 88.3kJ/mol and 87.3kJ/mol. The DSC discovered that, curing behavior of BPF4-BOZ and BPF6-BOZ had only an exothermic peak, however, For BPF4-BOZ resin, its initial curing temperature was 222.8℃, exothermic peak temperature was 239℃, enthalpy was 283.3J/g, which initial curing temperature was 196.2℃, exothermic peak temperature was 218.9℃, enthalpy was 275.4J/g respectively for BPF6-BOZ resin. But BPA4-BOZ resin appeared two groups of exothermic peaks in the entire curing behavior. Because of its lower cyclizatio, it occurred dehydro-condensati-on and escaped the first exotherm between the uncyclizing methylol as well as the methylol and phenol hydroxyl. The second peak appears in 200℃-290℃scopes, responded for the open-ring of benzoxazine, its outset reaction temperature was 212.8℃, exothermic peak temperature was 251.1℃, the enthalpy was 138.8J/g. Because its cyclizatio was lower, the existence of hydroxyl, may catalyzed BPA4-BOZ curing open-ring, its enthalpy was far smaller than BPF4-BOZ's and BPF6-BOZ 's.After curing, the thermal stability of the above benzoxazine resin was researched by TGA. In pure nitrogen, BPF4-BOZ had the best thermal stability, the temperature of 5% weight loss was 410.4℃, char yields at 800℃were 63.60%. For BPF6-BOZ, its thermal stability was inferior to BPF4-BOZ the temperature in 5% weight loss was 301.1℃, char yields at 800℃were 58.8% separately, because it had the by-product such as dimmer. As for BPA4-B0Z, its thermal stability was situated between BPF4-BOZ and BPF6-BOZ, temperature of 5% weight loss were 348.2℃, char yields at 800℃were 62.6%.Finally, the dissolved performance test to the synthesis resins had been carried on : Because of the benzoxazine structure, three kinds of benzoxazine intermediately dissolved performance was better, can dissolve to besides the ethanol in the majority of polar solvent and non-polar solvent toluene, has the good machinable performance. Therefore, above three kinds of synthesized resin as the substrate, the toluene/acetone as the component solvent, glass cloth which processed By KH560 as strengthens the material, the glass cloth laminate was suppressed, and tested its performance. The result indicated that, the laminated suppressed with BOZ based on poly-rings, because has the higher cross-link density, the glass transition temperature compared to its corresponding BOZ based on two-rings to enhance 50-70℃, but their humidity-resistance was slightly inferior to BOZ based on two-rings. In addition, this article also studied fire-retarding and solder bolstering performance, discovered that compared to the BPA-BOZ, BPF-BOZ had the flexibility and the high temperature stability, therefore had better fire-retarding and solder bolstering performance. Through compares several kind of resins the general performances to discover that, for BPF4-BOZ, fire-retarding performance reached the standard of UL94V-1, the time of solder bolstering at 288℃was longer than 60s, glass transition temperature Tg was 238℃.In addition, for BPF6-BOZ, fire-retarding performance reached the standard of UL94V-2, the time of solder bolstering at 288℃was than 360s, glass transition temperature (Tg) was 228℃, has the better general performance.