Method for preparing supercritical hydrotalcite grafted with flame retardant

Abstract

The invention belongs to the field of organic functional molecule modified hydrotalcite and particularly relates to hydrotalcite of which the surface is grafted with an organophosphorus heterocyclic compound, and a preparation method of hydrotalcite. According to the method disclosed by the invention, a silane coupling agent serves as a bridging linker in supercritical carbon dioxide, and the organophosphorus heterocyclic compound is chemically grafted to the surface of hydrotalcite, wherein the silane coupling agent accounts for 0.1-50 wt% of the total weight of hydrotalcite of which the surface is grafted with organic functional molecules, the organophosphorus heterocyclic compound accounts for 0.1-50 wt%, and the balance is hydrotalcite. The hydrotalcite of which the surface is grafted with the organic functional molecules, disclosed by the invention, can serve as a functional assistant, is added into macromolecular materials, such as polyolefins, polyesters, epoxy resin, binders, coating materials, rubber or fibers, and is used for improving the thermal ageing resistance, photo-aging resistance, heat resistance, transparency, flame retardance and the like of the prepared materials.

Description

technical field [0001] The invention belongs to the field of hydrotalcites modified by organic functional molecules, in particular to a preparation method of hydrotalcites grafted with phosphorus-containing flame retardants on the surface in supercritical carbon dioxide. Background technique [0002] In order to increase the flame retardant properties of polymer materials, a large amount of organic and inorganic flame retardants are often added to them, but adding these organic or inorganic flame retardants to the polymer material matrix through conventional physical mixing will reduce the overall performance of the material , and the chemical bonding of inorganic fillers and organic functional additives can greatly reduce the amount of fillers used and improve the overall performance of the material. [0003] When a certain scale of inorganic fillers such as hydrotalcite, montmorillonite, calcium carbonate, vermiculite, hydrotalcite, zinc oxide, titanium dioxide, iron oxide...

AI Technical Summary

Problems solved by technology

[0004] Hydrotalcite is used as an inorganic filler in polymers, which can improve the overall performance of polymers. However, due to the presence of hydroxyl groups and unsaturated residual bonds on its surface, it shows strong hydrophilicity and poor compatibility with polymers. , it is difficult to disperse evenly, so it is necessary to carry out surface treatment on hydrotalcite, such as using silane coupling agent treatment (US Patent US6809149B2), surfactant treatment, surface grafting treatment, oligomer and macromolecule coating treatment, etc. Its surface is hydrophobic, which solves the compatibility problem with polymers

[0005] The addition of organic functional additives such as flame retardants, antioxidants, ultraviolet absorbers, light stabilizers, heat stabilizers, antistatic agents, etc. can improve the comprehensive performance of polymers, and the functional additives commonly used are mostly molecular weight The lower compound has low thermal stability and poor extraction resistance, and will slowly migrate to the surface of the material as time goes on, causing secondary pollution to the environment and affecting its efficiency in polymers

Today's development trend is to prepare functional additives with ideal molecular weight, such as grafting functional additives to polymer chains (US Patent US6936659B2: polymer-bonded functional agents), to reduce the loss of functional additives, which requires more technology. High; the flame retardant efficiency can be greatly improved by grafting the flame retardant onto the surface of the inorganic particles through the silane coupling agent, but the inoculation rate of the flame retardant on the particle surface is low in this method, and usually it must be mixed with toluene, xylene, dichloro The grafting reaction is carried out in environmentally unfriendly solvents such as methane, and no method has been found that can not only increase the grafting rate of flame retardants on the surface of inorganic particles, but also achieve it under environmentally friendly conditions.

[0006] We noticed that in the literature reports so far, the surface grafting of functional nanoparticles and flame retardants is prepared in organic solvent medium, the grafting rate is low, the organic solvent is volatile, and the environment is not friendly.

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