Phosphorus-containing benzoxazine resin with various substituents and method for preparing the same

1. A phosphorus-containing benzoxazine resin of a structure shown as a formula (I):

wherein, R1˜R3 respectively comprise one selected from the group consisting of hydrogen, C1-C6 alkyl, C3˜C6 cyclic alkyl, and phenyl.

2. A phosphorus-containing benzoxazine resin of a structure shown as a formula (V):

wherein, R4 is one selected from the group consisting of hydrogen, C1˜C6 alkyl, C3˜C6 cyclic alkyl, and phenyl.

3. A method for preparing a phosphorus-containing benzoxazine resin, the phosphorus-containing benzoxazine resin of a structure shown as a formula (I):

the method comprising the following steps:

(a) in a first stage, dissolving phosphorus-containing diamine and 2-hydroxybenzaldehyde in a mixing solvent, setting a Dean-Stark device to execute a draining reaction at the reflux temperature, generating an intermediate (III) having an imine band, and removing a hydrophobic solvent from the mixing solvent;

(b) in a second stage, mixing NaBH 4 in the reacting system in the first stage to react at a room temperature after the first stage finishes and the reflux temperature drops to the room temperature, and then mixing the reacting liquid in the water to separate an intermediate (II); and

(c) in a third stage, dissolving the intermediate (II) in a solvent, mixing a formaldehyde solution or a paraformaldehyde in the solution with the intermediate (II) to stir for a duration at a temperature of 35° C., raising the temperature to a reflux temperature from 35° C., and removing the solvent by a spin concentrator to obtain the phosphorus-containing benzoxazine resin comprising the structure shown as the formula (I).

4. The method according to claim 3 , wherein the mixing solvent in the step (a) is at least one selected from the group consisted of DMAC/Toluene, NMP/Toluene, DMSO/Toluene, DMAC/Xylene, NMP/Xylene, and DMSO/Xylene, and the hydrophobic solvent comprises Toluene and Xylene.

5. The method according to claim 3 , wherein the solvent in the step (c) is at least one selected from the group consisted of Toluene, Xylene, CHCl 3 , and Dioxane.

6. A method for preparing a phosphorus-containing benzoxazine resin, the phosphorus-containing benzoxazine resin of a structure shown as a formula (V):

the method comprising the following steps:

(a) in a first stage, dissolving phosphorus-containing diether-amine (VIII) and 2-hydroxybenzaldehyde in a mixing solvent, setting a Dean-Stark device to execute draining reaction at the reflux temperature, generating an intermediate (VII) having an imine band, and removing a hydrophobic solvent from the mixing solvent;

(b) in a second stage, mixing NaBH 4 in the reacting system in the first stage to react at a room temperature after the first stage finishes and the reflux temperature drops to the room temperature, and then mixing the reacting liquid in the water to separate an intermediate (VI); and

(c) in a third stage, dissolving the intermediate (VI) in a solvent, mixing a formaldehyde solution or a paraformaldehyde in the solution with the intermediate (II) to stir for a duration at a temperature of 35° C., raising the temperature to a reflux temperature from 35° C., and removing the solvent by a spin concentrator to obtain the phosphorus-containing benzoxazine resin comprising the structure shown as the formula (V).

7. The method according to claim 6 , wherein the mixing solvent in the step (a) is at least one selected from the group consisted of DMAC/Toluene, NMP/Toluene, DMSO/Toluene, DMAC/Xylene, NMP/Xylene, and DMSO/Xylene, and the hydrophobic solvent comprises Toluene and Xylene.

8. The method according to claim 6 , wherein the solvent in the step (c) is at least one selected from the group consisted of Toluene, Xylene, CHCl 3 , and Dioxane.