CN-117164794-B - Single-component intumescent flame retardant with layered structure and super-strong char formation capability and preparation method thereof

CN117164794BCN 117164794 BCN117164794 BCN 117164794BCN-117164794-B

Abstract

The invention relates to a single-component intumescent flame retardant with layered structure and super-strong char formation capability and a preparation method thereof, the method firstly reacts 3, 4-dihydroxybenzaldehyde with organic diamine rich in benzene rings or nitrogen heterocycles to prepare an intermediate product, and then organically combining the intermediate product with phytic acid, and constructing a macromolecular crosslinked network through esterification crosslinking reaction to prepare the single-component intumescent flame retardant with a layered structure and super-strong char forming capability. Compared with the common ammonium phytate flame retardant, the flame retardant prepared by the invention has water washing resistance, and can form a super-strong, compact and hard carbon layer during combustion. The polymer material can be endowed with excellent flame retardant property and flame retardant durability. In addition, the flame retardant has a layered structure, so that the flame retardant can be dispersed in a polymer more uniformly, and the mechanical property of the polymer can be obviously improved. The flame retardant disclosed by the invention is simple in preparation process, strong in practicability and very wide in application prospect.

Inventors

ZHU ZONGMIN
WANG YADONG

Assignees

武汉纺织大学

Dates

Publication Date: 20260508
Application Date: 20230801

Claims (3)

1. The preparation method of the single-component intumescent flame retardant with a layered structure and super-strong char formation capability is characterized by comprising the following steps: step 1, mixing 3, 4-dihydroxybenzaldehyde and organic diamine in absolute ethyl alcohol, stirring for 1-6 hours at a reaction temperature of 25-80 ℃, cooling to room temperature, and performing suction filtration, ethanol washing and drying to obtain an intermediate A; In the step 1, the molar ratio of the 3, 4-dihydroxybenzaldehyde to the organic diamine is (2-5) 1, wherein the organic diamine in the step 1 is any one or more of 4,4' -diaminodiphenyl methane, 4' -diaminodiphenyl sulfone, 3, 5-diaminotriazole, 4' -diaminodiphenyl ether, 4' -diaminoterphenyl, 4' -diaminodiphenyl sulfide and 2,2' -diamino-4, 4' -dithiazole; step 2, dispersing the intermediate A prepared in the step 1 in a solvent to form a uniform suspension, slowly dripping a phytic acid solution, stirring for 5-12 hours at a reaction temperature of 25-100 ℃, and after the reaction is finished, performing suction filtration, washing with deionized water and drying to obtain the single-component intumescent flame retardant with a layered structure and super-strong char forming capability; The molar ratio of the intermediate A to the phytic acid in the step 2 is (0.2-5): 1.
2. The method for preparing a single-component intumescent flame retardant with a layered structure and super-strong char formation ability according to claim 1, wherein the solvent in the step 2 is any one of acetonitrile, toluene, benzene, acetone, chloroform and water.
3. A one-component intumescent flame retardant having a layered structure and super char formation capability, characterized by being prepared by the preparation method of any one of claims 1-2.

Description

Single-component intumescent flame retardant with layered structure and super-strong char formation capability and preparation method thereof Technical Field The invention relates to the field of organic flame retardants, in particular to a single-component intumescent flame retardant with a layered structure and super-strong char forming capability and a preparation method thereof. Background The polymer material has excellent comprehensive performance, and is widely applied to the fields of textile fabrics, electronic appliances, buildings, automobiles and the like, and becomes an essential basic material in national economy construction. However, the polymer material is very inflammable, and once ignited, the flame is difficult to extinguish, which can bring about serious fire. Therefore, flame retardant treatment of the polymer material is very necessary. The intumescent flame retardant has low smoke, excellent char formation capability and heat inhibiting effect, and is widely applied to high polymer materials. When the intumescent flame retardant burns, a compact expansion protective layer can be formed on the surface of the high polymer material, so that the burning is effectively slowed down or interrupted. The common intumescent flame retardant in the market is formed by mixing ammonium polyphosphate, pentaerythritol and melamine. However, most of the flame retardant components are inorganic substances, the dispersibility and compatibility of the flame retardant components in the organic polymer base material are poor, the mechanical properties of the polymer material can be damaged, and meanwhile, the flame retardant can migrate to the surface of the base material along with the time, so that the flame retardant durability is affected. On the other hand, the mixed flame retardant has poor water resistance, and the flame retardant property of the flame-retardant modified polymer material can be seriously reduced under the condition of water. The single-component intumescent flame retardant is characterized in that a plurality of flame retardant groups are constructed on one molecule, and has the advantages of better dispersibility and compatibility. With the enhancement of sustainable development concept in recent years, biological-based materials are receiving attention from a large number of scholars. Phytic acid is used for preparing the intumescent flame retardant because of high phosphorus content and good char formation. At present, some students use phytic acid and simple organic amine molecules to perform acid-base neutralization reaction, so that a series of phytic acid ammonium salt flame retardants are prepared. Although these flame retardants exhibit good flame retardant properties, they are all salt compounds (ionic bonds), are readily soluble in water and are not water-washable, and therefore their use is limited. If Li et al use phytic acid and 1, 6-hexamethylenediamine as raw materials, water as solvent to carry out acid-base neutralization reaction, and remove the water solvent by rotary evaporation, the phytate flame retardant PA-HAD(Tough and flame-retardant poly(lactic acid)composites prepared via reactive blending with biobased ammonium phytate and in situ formed crosslinked polyurethane,composites communications,8,52-57), is prepared, and 5wt% of the flame retardant is added, so that polylactic acid can pass through UL-94V-0 level, and the oxygen index reaches 26%. This work was also filed and issued patent (CN 108047494 a). In the preparation method of the phytate flame retardant of the scholars, the prepared flame retardant is water-soluble. Gao et al prepared phytic acid piperazine salt flame retardant PHYPI(A novel bio-based flame retardant for polypropylene from phytic acid,Polymer Degradation and Stability,161,298-308) by using phytic acid and piperazine as raw materials and water as a solvent and applied the phytic acid piperazine salt flame retardant to polypropylene, and also obtained good flame retardant effect. However, the flame retardant is also water-soluble and suffers from the characteristic of being not resistant to water washing. In addition, the phytate flame retardant is prepared by using phytic acid and organic amine molecules through a simple acid-base neutralization reaction, and the organic amine molecules are usually small molecules such as aliphatic amine, aromatic amine, melamine, piperazine, aminoethylpiperazine, imidazole and the like. Therefore, the prepared flame retardant has insufficient char forming ability, so that a high-strength expanded carbon layer cannot be formed, and the high polymer cannot be efficiently protected. The PHYPI flame retardant prepared as described above had a carbon residue of only 34.7% under a nitrogen atmosphere at 700 ℃. Disclosure of Invention The invention aims to provide a single-component intumescent flame retardant with a layered structure and super-strong char formation capability and a preparation method ther