CN-121991123-A - Preparation method and application of polyhydroxy phosphine nitrogen flame retardant

Abstract

The invention relates to a preparation method and application of a polyhydroxy phosphine nitrogen flame retardant, which is prepared by recycling nitrogenous polyol in degradation products of thermosetting ester epoxy/amine condensate, and further reacting, and comprises the following steps of (1) conducting alcoholysis on the thermosetting ester epoxy/amine condensate by using glycol and sodium hydroxide to obtain degradation liquid, (2) filtering the degradation liquid, removing glycol by rotary evaporation, conducting ethanol aging and desalting, regulating pH to be neutral, conducting rotary evaporation to obtain nitrogenous polyol EP/N-8OH, (3) mixing the EP/N-8OH with triethylamine and tetrahydrofuran, dropwise adding diphenyl phosphinoyl chloride under nitrogen protection, and conducting post-reaction treatment to obtain P, P-diphenyl phosphinic acid-3- [ (5- { [ bis (2, 3-dihydroxypropyl) amino ] methyl } -3, 5-trimethylcyclohexyl) (2, 3-dihydroxypropyl) amino ] -2-hydroxypropyl ester (polyhydroxy phosphine nitrogen flame retardant, DPP-P). The invention also provides an application method of the polyhydroxy phosphine nitrogen flame retardant, wherein DPP-P is mixed with bisphenol A epoxy resin E-51, curing agent 1,2,3, 6-tetrahydrophthalic anhydride and catalyst N, N-dimethylaniline, and the mixture is preheated, defoamed and cured by step heating, so that the prepared flame retardant modified epoxy resin E51-DPP has good flame retardant property and mechanical property.

Inventors

• LI WEN
• LIU BO
• MAO XINYUE
• MA HANBING
• YAN MAOSHENG

Assignees

• 西南科技大学

Dates

Publication Date

20260508

Application Date

20260114

Claims (3)

1. 1. The preparation method of the polyhydroxy phosphine nitrogen flame retardant is characterized by comprising the following steps: a. The degradation of the epoxy condensate, namely placing the epoxy condensate and ethylene glycol in a reaction container according to the mass ratio of 1:9, introducing nitrogen under alkaline condition, and carrying out alcoholysis at 180 ℃ to obtain degradation liquid; b. filtering the degradation liquid obtained in the step a, removing glycol from the filtrate by rotary evaporation under reduced pressure, aging for 72 hours by ethanol to remove sodium salt, filtering again, adjusting the filtrate to be neutral, and removing ethanol by rotary evaporation to obtain the nitrogen-containing polyol; c. B, mixing the nitrogenous polyol obtained in the step b with triethylamine and tetrahydrofuran, and uniformly stirring at room temperature; d. And C, dropwise adding diphenyl phosphinoyl chloride into the mixture in the step C under the protection of nitrogen and ice water bath, heating to 65 ℃ after dropwise adding, reacting for 24 hours, adding ethyl acetate after the reaction is finished, filtering to remove precipitate, washing the filtrate to be neutral, and performing rotary evaporation under reduced pressure to obtain the P, P-diphenyl phosphinic acid-3- [ (5- { [ bis (2, 3-dihydroxypropyl) amino ] methyl } -3, 5-trimethylcyclohexyl) (2, 3-dihydroxypropyl) amino ] -2-hydroxypropyl ester.
2. 2. The preparation method according to claim 1, wherein the alkaline condition in the step a is adjusted to ph=11 by a sodium hydroxide solution, the degradation time in the step a is 45 minutes, the mass fraction of the nitrogen-containing polyol, the triethylamine and the tetrahydrofuran in the step c is 11 parts of the nitrogen-containing polyol, 21 parts of the triethylamine and 100-150 parts of the tetrahydrofuran, and the mass fraction of the diphenylphosphinoyl chloride in the step d is 55 parts.
3. 3. An application method of a polyhydroxy phosphine nitrogen flame retardant is characterized by comprising the steps of uniformly mixing P, P-diphenyl phosphinic acid-3- [ (5- { [ bis (2, 3-dihydroxypropyl) amino ] methyl } -3, 5-trimethylcyclohexyl) (2, 3-dihydroxypropyl) amino ] -2-hydroxypropyl ester prepared by any one of claims 1-2 with bisphenol A type epoxy resin E-51 at 80 ℃, adding an anhydride curing agent 1,2,3, 6-tetrahydrophthalic anhydride and an accelerator N, N-dimethylaniline, stirring until the mixture is clarified, injecting the mixture into a mold, conducting vacuum defoaming, and conducting step heating curing at 120 ℃ per 2 h+140 ℃ per 2 h+160 ℃ per 2h to obtain the flame retardant epoxy resin, wherein the mass of the P, P-diphenyl phosphinic acid-3- [ (5- { [ bis (2, 3-dihydroxypropyl) amino ] methyl } -3, 5-trimethylcyclohexyl) (2, 3-dihydroxypropyl) amino ] -2-hydroxypropyl ester is 25 percent of the epoxy resin.

Description

Preparation method and application of polyhydroxy phosphine nitrogen flame retardant The invention relates to a preparation method and application of a polyhydroxy phosphine nitrogen flame retardant. Background Epoxy resins are widely used in the fields of coating, electronic packaging, aerospace composite materials and the like due to their excellent thermal stability, mechanical properties and adhesive strength. However, the three-dimensional crosslinked network structure thereof causes difficult reprocessing and recycling after solidification, and a large amount of generated wastes are mainly treated by landfill or incineration, so that not only is the resource wasted, but also serious environmental problems are brought. Therefore, development of a technology for efficiently recovering and utilizing an epoxy resin cured product has become a key issue for realizing recycling economy of a polymer material. In recent years, researchers have actively explored in the field, mostly, the materials are prepared by extracting and recovering monomers from degradation products, or the degradation products are directly used as active components in a regenerated resin curing system, for example, AN Le and the like adopt ethylene glycol to degrade and recover glutaric anhydride curing epoxy resin by heating for 2 hours at 180 ℃ and realize ring-closure recovery and remanufacturing of epoxy composite materials, wu et al 27 are used for degrading bio-based thermosetting epoxy resin through methanol low-temperature alcoholysis, and the degraded products are used as a material for synthesizing amine thermosetting resin, so that the materials are reused in the epoxy field, the ring-closure recovery is realized, and An team researches on the selective breaking behavior of ester bonds in unsaturated polyester resin (UP) by a K2CO 3/ethylene glycol catalytic system. Under normal pressure and lower temperature (180 ℃), the ester group in UP is hydrolyzed, degradation products are mainly linear macromolecular products containing carboxyl and benzene ring structures, glycol, phthalate small molecules and the like, zhang and the like take carbon fiber reinforced epoxy resin composite materials with high glass transition temperature as research objects, and the matrix resin is degraded into oligomers under mild conditions by utilizing the swelling effect of ethanol on the resin and the strong coordination effect of Lewis acid ZnCl2 and C-N bonds. The degradation products can be added into a new epoxy resin curing system for recycling, when the addition amount is 15%, the new resin can still keep better mechanical properties, zhao and the like can be added into the original epoxy resin to be used as a filler, and the degradation products with low addition amount have little influence on the thermal performance and mechanical properties of the resin. The prior art (e.g., CN 118724696A) has reported that the fractional depolymerization of glycidyl ester epoxy curatives by Ethylene Glycol (EG) and sodium hydroxide successfully recovered high purity 4-cyclohexene-1, 2-dicarboxylic acid monomer and achieved closed loop repolymerization, with the regenerated epoxy resin performance comparable to the original resin. The process provides an effective path for chemical recovery of the ester epoxy/amine cure. However, the products of such technical routes are mainly focused on recovering the original monomer or base chemical, failing to fully exploit the conversion potential of other components (especially nitrogen-containing building blocks) in the degradation product, and the value-enhancing path of the recovered product is relatively single. Meanwhile, in order to meet the strict requirements of the fields of electronics, electricity, transportation and the like on the flame-retardant safety of the material, the flame-retardant modification of the epoxy resin is very important. Phosphorus flame retardants, in particular DOPO (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) and its derivatives, are widely used because of their efficient gas and condensed phase synergistic flame retarding mechanism. However, most of traditional DOPO flame retardants are of small molecules or rigid structures, so that the mechanical properties of the materials are often seriously damaged while the epoxy resin is endowed with good flame retardant property, and particularly the toughness is reduced, so that the application of the DOPO flame retardants in high-end structural function integrated composite materials is restricted. Therefore, developing a novel flame retardant which can not only endow epoxy resin with excellent flame retardance, but also maintain and even enhance the mechanical properties of the epoxy resin is a technical problem to be solved in the field. In summary, the prior art has two spaces for further optimization, namely, the recycling technology of epoxy resin waste has realized monomer closed loop, but the utilization of other compo