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CN-122010858-A - Flame-retardant polyhydroxy melamine derivative and preparation method thereof

CN122010858ACN 122010858 ACN122010858 ACN 122010858ACN-122010858-A

Abstract

The invention discloses a flame-retardant polyhydroxy melamine derivative and a preparation method thereof, belonging to the field of high polymer material synthesis. The preparation method of the invention uses 2, 2-dimethylolpropionic acid methyl ester and hexamethylol melamine as raw materials, and reforms the melamine through transesterification. Compared with the prior art, the method can greatly improve the product quality, so that the method can meet the production requirements of high-transparency epoxy resin and polyester resin, and has good popularization and application values.

Inventors

  • JIANG WENWEI
  • TANG YIN
  • YU JUNFAN
  • GUO ZHIGANG
  • LI XIANG
  • LI GANG

Assignees

  • 四川金象赛瑞化工股份有限公司

Dates

Publication Date
20260512
Application Date
20260206

Claims (8)

  1. 1. The preparation method of the flame-retardant polyhydroxy melamine derivative is characterized in that 2, 2-dimethylolpropionic acid methyl ester and hexamethylol melamine are used as raw materials, hydroxyl-terminated monomers shown in a formula I are obtained through transesterification, 。
  2. 2. The method of manufacturing according to claim 1, comprising: S1, adding metered hexamethylol melamine, 2-dimethylolpropionic acid methyl ester and a base catalyst into a dispersing agent, and reacting for 5-8 hours at 75-100 ℃; s2, neutralizing the base catalyst, standing for phase separation, and removing low-boiling substances from the lower layer to obtain the hydroxyl-terminated monomer shown in the formula I.
  3. 3. A process for preparing the same according to claim 2, wherein, The mole ratio of the hexamethylol melamine to the 2, 2-dimethylol methyl propionate is 1:6-7.
  4. 4. A process for preparing the same according to claim 2, wherein, The dispersing agent is toluene or xylene, and the dosage of the dispersing agent is 4-10 times of the mass of the hexamethylol melamine.
  5. 5. A process for preparing the same according to claim 2, wherein, The alkali catalyst is potassium hydroxide or sodium hydroxide, and the dosage of the alkali catalyst is 1% -2% of the mass of the hexamethylol melamine.
  6. 6. A process for preparing the same according to claim 2, wherein, The base catalyst is neutralized with formic acid, acetic acid, benzoic acid or hydrochloric acid.
  7. 7. A process for preparing the same according to claim 2, wherein, Standing and phase-separating at 40-60 ℃; the lower low-boiling substances were removed by concentration under reduced pressure.
  8. 8. Flame retardant polyhydroxy melamine derivative obtained by the process according to any one of claims 1 to 7.

Description

Flame-retardant polyhydroxy melamine derivative and preparation method thereof Technical Field The invention relates to the field of high polymer material synthesis, and in particular provides a flame-retardant polyhydroxy melamine derivative and a preparation method thereof. Background Epoxy resin and polyester resin are widely applied to the fields of aerospace, electronic and electric appliances and composite materials due to excellent mechanical properties, adhesive properties and electrical insulation properties. However, since such resins are mainly composed of carbon, hydrogen, and oxygen elements, they are generally low in Limiting Oxygen Index (LOI) and are extremely flammable, which limits their application in fire-proof demanding scenes. Melamine has extremely high nitrogen content (about 66%), can decompose and release nitrogen (non-combustible gas) at high temperature and promote carbon formation, and is a recognized green high-efficiency flame-retardant element. However, the common melamine has poor solubility, and is difficult to directly participate in the polymerization of the resin. Gungor Gunduz, NAGEHAN KESKIN et al, in "Synthesis and characterization of solvent-free hybrid alkyd resin with hyperbranched melamine core", synthesized a hydroxyl-terminated hyperbranched monomer using hexamethylol melamine (HMM) as the core, reacted with 2, 2-dimethylolpropionic acid (DMPA). However, because the reaction is carried out under the condition of acid catalyst such as p-toluenesulfonic acid (p-TSA) and the like by taking acid as a reactant, water is generated in the reaction process, and the reaction temperature needs to reach 140 ℃. The raw material hexamethylol melamine (HMM) has strong heat sensitivity, under the high temperature and acidic condition, the methylol among HMM molecules is easy to generate self-condensation reaction to generate ether bond, so that the system is suddenly increased in viscosity or even is burst and aggregated (gelled) in the middle and later period of the reaction, and the product is inevitably subjected to thermal oxidation at the high temperature of more than 140 ℃ for a long time, so that the color of the finally obtained resin is yellow or deep. This is a fatal defect for epoxy resin applications requiring high transparency, severely limiting the field of application of the product. Disclosure of Invention The invention provides a preparation method of flame-retardant polyhydroxy melamine derivative suitable for industrial mass production, aiming at the defects of the prior art. The invention solves the technical problems by adopting a technical scheme that the preparation method of the flame-retardant polyhydroxy melamine derivative is characterized in that 2, 2-dimethylolpropionic acid methyl ester and hexamethylol melamine are used as raw materials, hydroxyl-terminated monomers shown in a formula I are obtained through transesterification, 。 Preferably, the preparation method of the flame retardant polyhydroxy melamine derivative comprises the following steps: S1, adding metered hexamethylol melamine, 2-dimethylolpropionic acid methyl ester and a base catalyst into a dispersing agent, and reacting for 5-8 hours at 75-100 ℃; s2, neutralizing the base catalyst, standing for phase separation, and removing low-boiling substances from the lower layer to obtain the hydroxyl-terminated monomer shown in the formula I. Preferably, the molar ratio of hexamethylol melamine to methyl 2, 2-dimethylolpropionate is 1:6 to 7, particularly preferably 1:6 to 6.3. Preferably, the dispersing agent is toluene or xylene, and the amount of the dispersing agent is 4 to 10 times, particularly preferably 6 to 10 times, the mass of the hexamethylol melamine. Preferably, the alkali catalyst is potassium hydroxide or sodium hydroxide, and the dosage of the alkali catalyst is 1% -2% of the mass of the hexamethylol melamine, and particularly preferably 1.8% -2%. Preferably, the reaction temperature in the step S1 is 80-90 ℃ and the reaction time is 5.5-6.5 hours. The base catalyst is preferably neutralized with formic acid, acetic acid, benzoic acid or hydrochloric acid, and particularly preferably neutralized with acetic acid or formic acid. Preferably, after the alkali catalyst is neutralized, the mixture is allowed to stand at 40 to 60 ℃, and the phase separation is particularly preferably 47 to 53 ℃. Preferably, the lower low boiling substances are removed by concentration under reduced pressure. The vacuum degree of the reduced pressure concentration is preferably-0.095.+ -. 0.01MPa. The hydroxyl-terminated monomer shown in the formula I is prepared from the raw materials of the methyl 2, 2-dimethylolpropionate and the hexamethylol melamine through transesterification, and has the following outstanding beneficial effects compared with the prior art: The product quality is high, and the production requirements of high-transparency epoxy resin and polyester resin can be met; and (II) t