Epoxy resin fire retardant and preparation method thereof, as well as epoxy resin composition prepared from fire retardant

Abstract

The invention discloses an epoxy resin fire retardant and a preparation method thereof, as well as an epoxy resin composition prepared from the fire retardant. The fire retardant structurally comprises CNT (carbon nano tube)-nitrogen-phosphorus which is combined by chemical bonds. Not only can the fire retardant in a process of being heated and decomposing generate a large number of wormlike expansion carbon layers which are inlaid with one other so as to reduce thermal conductivity, but also can release phosphorus-containing strong acid and nitrogen-containing inert gas which can be respectively used for promoting an anti-flamed base material to dehydrate into carbon and reducing oxygen concentration. By a chemical reaction method, the fire retardant can be introduced into an epoxy cross-linking structure, because of the existence of the strong-polar chemical bonds, the fire retardant is prevented from migrating to the surface of a material, the epoxy resin composition is suitable forelectric and electrical engineering fields, the service life of the material is prolonged, and the safety of the material is improved.

Description

technical field [0001] The invention belongs to the field of epoxy resin, and in particular relates to an epoxy resin flame retardant, a preparation method thereof, and an epoxy resin composition prepared by using the flame retardant. Background technique [0002] Epoxy resin has excellent mechanical properties, electrical insulation, chemical corrosion resistance, heat resistance and adhesiveness after curing, and is widely used in many fields such as the automobile industry, electronics and electricity. Since epoxy resin is mainly composed of C, H, O and other elements, it has high flammability and continues to burn after leaving the fire, which is easy to cause fire. This shortcoming makes epoxy resin composite materials a great safety hazard. [0003] The limiting oxygen index (LOI) of unmodified epoxy resin is only about 19%. It can continue to burn in the air and belongs to flammable products. The flame retardancy of epoxy resin has become the focus of its application....

AI Technical Summary

Problems solved by technology

Halogen flame retardants will produce a large amount of toxic gases when they burn, which seriously pollute the environment and have been phased out. The thermal stability, compatibility with polymer matrix, permeability resistance and The processing performance is poor. The addition of nano-flame retardants to polymers will significantly reduce the mechanical properties of materials. The intumescent synergistic flame retardants represented by phosphorus-nitrogen have little improvement in the LOI of materials due to the lack of effective carbon sources.

[0004] US5277887 uses ammonium orthophosphate and phosphorus pentoxide as raw materials to prepare water-insoluble chain ammonium polyphosphate (APP) as a flame retardant for epoxy resins. The strong acid produced by the combustion and decomposition of the flame retardant promotes the development of the flame-retardant substrate. Dehydration into carbon, but due to the lack of synergistic flame retardant effect of the flame retardant system, the improvement of the material LOI is small

[0005] EP3531500 proposes to coat APP with melamine formaldehyde resin to form a microcapsule structure, and the flame retardant effect reaches UL-94VO level. Since the purpose of microencapsulation is mainly to reduce the water solubility of the flame retardant, there is no gap between the flame retardant and the matrix resin. The combination of chemical bonds makes the flame retardant easy to migrate and precipitate in the resin, which affects the performance of the material

[0006] CN105778152A provides a nitrogen-containing compound (3-amino-1,2,4-triazole) to modify carbon nanotubes, and introduce a compound with a high content of flame-retardant element N on the surface of carbon nanotubes. The synergistic flame retardant effect of nitrogen compounds improves the flame retardant performance of materials, but because the flame retardant does not have PO and PO when it is thermally decomposed 2 The generation of free radicals, has no effective termination effect on the activities of H, HO, and O generated in the quenching combustion reaction, and cannot be applied to indoor optical cables that have high requirements for flame retardancy.

[0007] CN102181074A proposes that carbon nanotubes and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) are firstly reacted with specific chemical groups to obtain DOPO with hydroxyl groups and acid-chlorinated carbon nanotubes, and then react DOPO with hydroxyl groups with acid-chlorinated carbon nanotubes to obtain a carbon nanotube flame retardant with DOPO groups, which can improve the flame retardancy of the material while maintaining Or improve the mechanical properties of the material, but there are easily degradable ester bonds in the flame retardant structure, and there are disadvantages in the preparation process, such as high production cost and the use of a large amount of polluting organic solvents

[0008] CN102199294A discloses a phosphaphenanthrene structure and epoxy-based hyperbranched polysiloxane, which integrates the molecular characteristics of the phosphorus-based flame retardant DOPO structure and hyperbranched polysiloxane, and has excellent flame retardancy, but The hyperbranched polysiloxane contains more silanol groups, and it is easy to dehydrate and condense into a Si-O-Si structure during storage, resulting in a cross-linked gel, which makes the flame retardant subject to severe stress during production, storage and transportation. big limit

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