Preparation of N and P flame retardant and application of N and P flame retardant in flame-retardant polymer

Abstract

The invention discloses preparation of an N and P flame retardant and application of the N and P flame retardant in a flame-retardant polymer. The N and P series flame retardant is a copolymer containing a DOPO group and an anhydride group, and the molecular structure of the N and P series flame retardant comprises at least one of a structural unit I and / or a structural unit II, a structural unit III and a structural unit IV, or at least one of structural units V-VI. The molecular structure of the N, P-series flame retardant contains DOPO groups, and the N, P-series flame retardant shows excellent flame retardance after being blended with polymer resin. Moreover, the molecular structure of the flame retardant contains anhydride groups, so that the flame retardant molecules and a polymer resin matrix have better compatibility, and the original mechanical properties of the polymer resin are retained to a great extent. Meanwhile, the anhydride group is used as an acid source, so that the effect of promoting char formation can be achieved. Due to the existence of the anhydride group, the problems of insufficient flame retardant efficiency, poor compatibility with a polymer resin matrix and the like when the DOPO flame retardant is independently used are solved.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, in particular to the preparation of an N, P series flame retardant and the application of the same in flame retardant polymers. Background Art

[0002] In recent years, based on the requirements of environmental protection, the development of renewable and low environmental load flame retardants has become an urgent need in the industry. Furfurylamine is a nitrogen-containing heterocyclic compound derived from agricultural waste (such as corn cobs, bagasse) biomass. The furan ring and amino active sites in its molecules can introduce flame retardant functional groups through condensation, addition and other reactions. Compared with traditional aniline raw materials, furfurylamine has the advantages of renewability, high reactivity (amino groups are easy to undergo condensation reactions with aldehydes, acid anhydrides, etc. to form a cross-linked network structure), and carbonization and synergistic effects (furan rings can undergo ring-opening polymerization at high temperatures, promote graphitization of carbon layers, and enhance barrier effects). Studies have been conducted to synthesize Schiff bases by condensing furfurylamine with formaldehyde, and then compounding them with phosphorus compounds to prepare N and P flame retardants, but most of these flame retardants are physically added, easy to migrate and precipitate, and affect the mechanical properties of materials.

[0003] Resin materials (such as polyurethane, epoxy resin, polyolefin, etc.) are widely used in construction, electronics, transportation and other fields due to their excellent mechanical properties, processability and chemical resistance. However, the limiting oxygen index (LOI) of most resin materials is only 18-22%, which is a flammable material. When burned, it releases a large amount of heat and toxic fumes (such as CO, HCN, etc.), which poses a serious safety hazard. For example, polyurethane decomposes rapidly at high temperatures, producing a free radical chain reaction, which accelerates the combustion process; polyolefin materials are prone to thermal degradation due to their carbon chain structure, forming flammable small molecule gases. Although traditional flame retardants (such as halogen flame retardants) can achieve excellent flame retardant effects, they have problems such as high toxicity and large smoke, and have been gradually replaced by environmentally friendly nitrogen-phosphorus flame retardant systems.

[0004] Nitrogen-phosphorus flame retardants achieve efficient flame retardancy through multi-path synergistic effects, which are gas phase flame retardancy (phosphorus element decomposes under heat to generate free radicals such as PO· and HPO·, captures H· and OH· in the combustion chain reaction, and inhibits flame propagation), condensed phase flame retardancy (nitrogen-containing components (such as triazines and amines) promote the dehydration of materials into carbon, forming a dense carbon layer to isolate oxygen and heat) and catalytic carbonization (the synergistic effect of phosphorus-nitrogen bonds (PN) can reduce the pyrolysis temperature of materials, accelerate the formation of carbon layers and improve their thermal stability). Among them, DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) has become the core component of the nitrogen-phosphorus flame retardant system due to its high thermal stability given by the phosphaphenanthrene ring structure and the high reactivity of the PO bond, but when used alone, it has problems such as insufficient flame retardant efficiency and poor compatibility with the substrate.

[0005] The current research on nitrogen and phosphorus flame retardants still faces the following challenges: (1) Poor compatibility of additive flame retardants: The flame retardant molecules are likely to disrupt the solvation structure of the resin matrix, resulting in a decline in mechanical properties; (2) Complex synthesis of reactive flame retardants: Most DOPO derivatives (such as phosphoramides) require multiple steps of reaction, with a cumbersome process and low yield; (3) Low utilization rate of bio-based raw materials: Existing flame retardants still rely on petroleum-based raw materials and fail to fully utilize the char-forming advantages of biomass components. Summary of the Invention

[0006] The object of the present invention is to provide a preparation of N and P-based flame retardants and their application in flame-retardant polymers to solve the problems existing in the above-mentioned prior art.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] One of the technical solutions of the present invention: An N and P-based flame retardant, the molecular structure of the N and P-based flame retardant includes structural unit I and / or structural unit II, and at least one of structural units III-IV, or at least one of structural units V-VI (that is, divided into two cases, one is structural unit I and / or structural unit II + one or more of structural units III-IV, and the other is structural unit I and / or structural unit II + one or more of structural units V-VI. The N and P-based flame retardant is a copolymer containing a DOPO group and an anhydride group):

[0009]

[0010] Among them, R1 is R2 and R3 are each independently selected from one of a hydrogen atom and a methyl group; R4 and R5 are each independently selected from one of a hydrogen atom, an alkyl group with 2-10 carbon atoms, and an alkylamine with 2-10 carbon atoms.

[0011] The molecular structure of the N and P-based flame retardant of the present invention contains a DOPO group and exhibits excellent flame retardant performance after being blended with a polymer resin. Moreover, the molecular structure of the flame retardant contains an anhydride group, which can make the flame retardant molecules have good compatibility with the polymer resin matrix and greatly retain the original mechanical properties of the polymer resin. At the same time, the anhydride group, as an acid source, can play a role in promoting char formation. The presence of the anhydride group compensates for the problems such as insufficient flame retardant efficiency and poor compatibility with the polymer resin matrix when the DOPO flame retardant is used alone.

[0012] Further, the structural formula of the N and P-based flame retardant is one of Formula I - Formula II:

[0013]

[0014] Among them, n1, n2, n3, and n4 are each independently selected from 0 to 50 (taking integers), and they are not all 0 at the same time.

[0015] The second technical solution of the present invention: The preparation method of the above N, P-based flame retardant includes the following steps:

[0016] Dissolve 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, formaldehyde, and furfurylamine in solvent A and react to obtain monomer A;

[0017] Dissolve the monomer A, an electron-withdrawing monomer, and an initiator in solvent B and carry out a polymerization reaction to obtain a copolymer, which is an N, P-based flame retardant including at least one of structural unit I and / or structural unit II, and structural unit III - structural unit IV in the molecular structure;

[0018] Mix the copolymer with an amine compound and carry out an amination reaction to obtain an aminated copolymer, which is an N, P-based flame retardant including at least one of structural unit I and / or structural unit II, and structural unit V - structural unit VI in the molecular structure;

[0019] The structural formula of the monomer A is

[0020] The electron-withdrawing monomer is one or more of the compounds shown in Formula V and Formula VI:

[0021] (Maleic anhydride and its derivatives), (Itaconic anhydride and its derivatives), where R2 and R3 are each independently selected from a hydrogen atom and a methyl group;

[0022] The structural formula of the amine compound is Among them, R4 and R5 are each independently selected from a hydrogen atom, an alkyl group with 2 - 10 carbon atoms, and an alkylamine with 2 - 10 carbon atoms.

[0023] The present invention uses a bio-based compound (furfurylamine) as a raw material, which conforms to the concept of green and recyclable, and the preparation method has a simple process, is safe, efficient, and pollution-free, and is suitable for large-scale production.

[0024] Furthermore, the electron-withdrawing monomer is preferably maleic anhydride or / and itaconic anhydride.

[0025] Furthermore, the solvent A includes one of water, alcohol solvents, ketone solvents, and ether solvents.

[0026] Furthermore, the molar ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), formaldehyde, and furfurylamine is 2 - 3:2 - 3:1.

[0027] Furthermore, the sum of the masses of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, formaldehyde and furfurylamine is 0.1-70% of the sum of the masses of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, formaldehyde, furfurylamine and solvent A.

[0028] Furthermore, the temperature of the reaction is 30-120 °C and the time is 1-48 h.

[0029] Furthermore, solvent A is preferably one of methanol, ethanol, acetone, methyl ethyl ketone and tetrahydrofuran.

[0030] Furthermore, the temperature of the reaction is preferably 50-80 °C and the time is preferably 1-12 h.

[0031] Furthermore, the initiator includes one or more of peroxide initiators and azo initiators.

[0032] Furthermore, solvent B includes one or more of organic acid alkyl esters, aromatic solvents, ether solvents and ketone solvents.

[0033] Furthermore, the molar ratio of the electron-withdrawing monomer to monomer A is 0.1-3:1.

[0034] Furthermore, the sum of the masses of the electron-withdrawing monomer and monomer A is 0.1-50% of the sum of the masses of monomer A, the electron-withdrawing monomer, the initiator and solvent B.

[0035] Furthermore, the mass of the initiator is 0.0001-5% of the sum of the masses of monomer A, the electron-withdrawing monomer, the initiator and solvent B.

[0036] Furthermore, the temperature of the polymerization reaction is 40-120 °C and the time is 1-12 h.

[0037] Furthermore, the peroxide initiators include one or more of benzoyl peroxide, diisopropylbenzene peroxide, cumene hydroperoxide, ditert-butyl peroxide, lauroyl peroxide and benzoic acid peroxide, and are preferably benzoyl peroxide.

[0038] Furthermore, the azo initiators include one or more of azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptonitrile, azoisobutyronitrile formamide, azodicyclohexylcarbonitrile and dimethyl azobisisobutyrate, and are preferably one or more of azobisisobutyronitrile and azobisisoheptonitrile.

[0039] Furthermore, the organic acid alkyl ester is one of ethyl formate, propyl formate, isobutyl formate, amyl formate, ethyl acetate, butyl acetate, isobutyl acetate, amyl acetate, isoamyl acetate, benzyl acetate, phenyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, butyl butyrate, isobutyl butyrate, isoamyl butyrate, ethyl isobutyrate, ethyl isoamylate, isoamyl isoamylate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, isoamyl benzoate, methyl phenylacetate, ethyl phenylacetate, propyl phenylacetate, butyl phenylacetate and isoamyl phenylacetate, and is preferably one of ethyl acetate, butyl acetate, amyl acetate and isoamyl acetate.

[0040] Furthermore, the aromatic hydrocarbon solvent is one of toluene, ethylbenzene, xylene and cumene, and is preferably toluene;

[0041] Furthermore, the ether solvent is one of dimethyl ether, methyl ethyl ether, diethyl ether, ethyl propyl ether, dipropyl ether, dibutyl ether, methyl propyl ether, methyl butyl ether, methyl isobutyl ether, methyl tert-butyl ether, methyl isoamyl ether, methyl tert-amyl ether, methyl cyclopentyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, tetrahydrofuran, tetrahydropyran and 1,4-dioxane, and is preferably one of ethylene glycol dimethyl ether, ethylene glycol diethyl ether and tetrahydrofuran.

[0042] Furthermore, the ketone solvent is one of acetone, butanone, cyclohexanone, methyl isobutyl ketone and methyl isopropyl ketone, and is preferably acetone or butanone.

[0043] Furthermore, the sum of the masses of the electron-withdrawing monomer and monomer A is preferably 0.1-30% of the sum of the masses of monomer A, the electron-withdrawing monomer, the initiator and solvent B, and more preferably 5-20%.

[0044] Furthermore, the mass of the initiator is preferably 0.04-2.5% of the sum of the masses of monomer A, the electron-withdrawing monomer, the initiator and solvent B.

[0045] Furthermore, the temperature of the polymerization reaction is preferably 40-100 °C, and more preferably 45-80 °C.

[0046] Furthermore, after the polymerization reaction, it further includes the steps of performing solid-liquid separation on the reaction system and drying the separated copolymer. The solid-liquid separation is carried out by known methods such as filtration, centrifugation, evaporation of the solvent, etc.

[0047] Furthermore, the molar ratio of the amine compound to the anhydride group contained in the copolymer is 1-50:1.

[0048] Further, the temperature of the amination reaction is 20 - 100 °C, and the time is 1 - 12 h.

[0049] Further, the amine compound is preferably one of ammonia, primary amines with 2 - 10 carbon atoms, and polyamines with 2 - 10 carbon atoms, more preferably one of ammonia, primary amines with 4 - 10 carbon atoms, and polyamines with 4 - 10 carbon atoms, still more preferably one of ammonia and diamines with 4 - 10 carbon atoms, and most preferably ammonia.

[0050] Further, the temperature of the amination reaction is preferably 20 - 60 °C, and the time is preferably 1 - 6 h.

[0051] Technical solution three of the present invention: Application of the above N, P - based flame retardant in the preparation of flame - retardant polymers.

[0052] Technical solution four of the present invention: A flame - retardant polymer composite material, by mass percentage, the raw materials include: 0.1 - 10% of the above N, P - based flame retardant and the balance of polymer resin matrix.

[0053] Technical solution five of the present invention: Preparation method of the above flame - retardant polymer composite material, including the following steps:

[0054] Mix the N, P - based flame retardant and the polymer resin matrix, and then form to obtain the flame - retardant polymer composite material.

[0055] Technical solution six of the present invention: Application of the above N, P - based flame retardant or the above flame - retardant polymer composite material in the preparation of flame - retardant materials.

[0056] The present invention discloses the following technical effects:

[0057] (1) The N, P - based flame retardant of the present invention uses a bio - based compound (furfurylamine) as a raw material, which conforms to the concept of green and recyclable. Moreover, the reagents selected in the whole preparation process of the present invention can be recycled. The preparation method of the present invention has simple process, is safe, efficient and pollution - free, and is suitable for large - scale production.

[0058] (2) The structure of the N, P - based flame retardant of the present invention contains acid anhydride groups. Utilizing its high - activity sites, it has good interfacial interaction with most polymer resin matrices (such as epoxy resin, etc.). At the same time, the acid anhydride group serves as an acid source, which can promote the effect of char formation, making up for the problems of insufficient flame - retardant efficiency and poor compatibility with polymer resin matrices when DOPO flame retardant is used alone.

[0059] (3) The N, P - based flame retardant of the present invention exhibits excellent flame - retardant performance after being blended with resin, and can greatly retain the original mechanical properties of the polymer resin matrix. Description of the Drawings

[0060] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0061] Figure 1 1H NMR and 13C NMR spectra of monomer A prepared in step (1) of Example 1;

[0062] Figure 2 1H NMR spectrum of the copolymer prepared in step (2) of Example 1;

[0063] Figure 3 FT-IR spectra of monomer A prepared in step (1), the copolymer prepared in step (2), and the aminated copolymer prepared in step (3) of Example 2;

[0064] Figure 4 Vertical burning test results (photos during combustion) of the flame-retardant polymer (EP) composites and pure EP prepared in Application Examples 5-8;

[0065] Figure 5 Vertical burning test results (photos during combustion) of the flame-retardant polymer (PA) composites prepared in Application Examples 13-14. Detailed Description of the Invention

[0066] Now, various exemplary embodiments of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0067] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0068] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this invention pertains. Although this invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of this invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the said documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0069] Without departing from the scope or spirit of this invention, various improvements and changes can be made to the specific embodiments of the specification of this invention, which are obvious to those skilled in the art. Other embodiments obtained from the specification of this invention are obvious to those skilled in the art. The specification and examples of this invention are merely exemplary.

[0070] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0071] It should be noted that those aspects not described in detail in this invention are all conventional operating means in the art and are not the focus of this invention.

[0072] As a first aspect of this invention, this invention provides an N, P-based flame retardant. The molecular structure of the N, P-based flame retardant includes structural unit Ⅰ and / or structural unit Ⅱ, and at least one of structural units Ⅲ - Ⅳ, or at least one of structural units Ⅴ - Ⅵ:

[0073]

[0074] Wherein, R1 is R2 and R3 are each independently selected from one of a hydrogen atom and a methyl group; R4 and R5 are each independently selected from one of a hydrogen atom, an alkyl group having 2 - 10 carbon atoms, and an alkylamine having 2 - 10 carbon atoms.

[0075] As a preferred embodiment of this invention, the structural formula of the N, P-based flame retardant is one of Formula Ⅰ - Formula Ⅱ:

[0076]

[0077] Wherein, n1, n2, n3, and n4 are each independently selected from 0 to 50 and are not all 0 at the same time.

[0078] As a second aspect of this invention, this invention provides a preparation method of the above-mentioned N, P-based flame retardant, including the following steps:

[0079] 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide Formaldehyde and furfurylamine are dissolved in solvent A and reacted to obtain monomer A (N,N - bis(9,10 - dihydro - 9 - oxa - 10 - phosphaphenanthrene - 10 - oxide) furfurylamine);

[0080] The monomer A, an electron - withdrawing monomer and an initiator are dissolved in solvent B and subjected to a polymerization reaction to obtain a copolymer, which is an N, P - based flame retardant including at least one of structural unit Ⅰ and / or structural unit Ⅱ, and structural unit Ⅲ - structural unit Ⅳ in the molecular structure;

[0081] The copolymer is mixed with an amine compound and subjected to an amination reaction to obtain an aminated copolymer, which is an N, P - based flame retardant including at least one of structural unit Ⅰ and / or structural unit Ⅱ, and structural unit Ⅴ - structural unit Ⅵ in the molecular structure;

[0082] The structural formula of the monomer A is

[0083] The electron - withdrawing monomer is one or more of the compounds shown in Formula Ⅴ and Formula Ⅵ:

[0084] (Maleic anhydride and its derivatives, preferably maleic anhydride, i.e., R2 = R3 = H), (Itaconic anhydride and its derivatives, preferably itaconic anhydride, i.e., R2 = R3 = H), where R2 and R3 are each independently selected from a hydrogen atom and a methyl group;

[0085] The structural formula of the amine compound is where R4 and R5 are each independently selected from a hydrogen atom, an alkyl group with 2 - 10 carbon atoms, and an alkylamine with 2 - 10 carbon atoms.

[0086] As an embodiment of the present invention, the reaction route of the monomer A is as follows:

[0087]

[0088] Monomer A is equivalent to introducing a furan ring into DOPO, which promotes the char - forming ability of the DOPO - based monomer during the flame - retardant process, and the double bond within the furan ring can be further modified for radical polymerization, DA reaction, etc., providing the possibility for further modification.

[0089] As a preferred embodiment of the present invention, the amine compound is preferably one of ammonia, primary amines having 2 to 10 carbon atoms, and polyamines having 2 to 10 carbon atoms, more preferably one of ammonia, primary amines having 4 to 10 carbon atoms, and polyamines having 4 to 10 carbon atoms, still more preferably one of ammonia and diamines having 4 to 10 carbon atoms, and most preferably ammonia.

[0090] As an embodiment of the present invention, the solvent A includes one of water, alcohol solvents, ketone solvents, and ether solvents, and is preferably one of methanol, ethanol, acetone, methyl ethyl ketone, and tetrahydrofuran;

[0091] And / or, the molar ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, formaldehyde, and furfurylamine is 2-3:2-3:1;

[0092] And / or, the sum of the masses of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, formaldehyde, and furfurylamine is 0.1-70% of the sum of the masses of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, formaldehyde, furfurylamine, and solvent A;

[0093] And / or, the temperature of the reaction is 30-120 °C, the time is 1-48 h, the temperature is preferably 50-80 °C, and the time is selected as 1-12 h.

[0094] As an embodiment of the present invention, the initiator includes one or more of peroxide initiators and azo initiators;

[0095] And / or, the solvent B includes one or more of organic acid alkyl esters, aromatic hydrocarbon solvents, ether solvents, and ketone solvents;

[0096] And / or, the molar ratio of the electron-withdrawing monomer to monomer A is 0.1-3:1;

[0097] And / or, the sum of the masses of the electron-withdrawing monomer and monomer A is 0.1-50% of the sum of the masses of monomer A, the electron-withdrawing monomer, the initiator, and solvent B, preferably 0.1-30%, and more preferably 5-20%;

[0098] And / or, the mass of the initiator is 0.0001-5% of the sum of the masses of monomer A, the electron-withdrawing monomer, the initiator, and solvent B, preferably 0.04-2.5%;

[0099] And / or, the temperature of the polymerization reaction is 40-120 °C, the time is 1-12 h, the temperature is preferably 40-100 °C, and more preferably 45-80 °C.

[0100] As a preferred embodiment of the present invention, the peroxide initiator includes one or more of benzoyl peroxide, dicumyl peroxide, cumene hydroperoxide, di-tert-butyl peroxide, lauroyl peroxide, and benzoic acid peroxide, preferably benzoyl peroxide;

[0101] And / or, the azo initiator includes one or more of azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptonitrile, azoisobutyronitrile carboxamide, azodicyclohexylcarbonitrile, and dimethyl azobisisobutyrate, preferably one or more of azobisisobutyronitrile and azobisisoheptonitrile.

[0102] As a preferred embodiment of the present invention, the organic acid alkyl ester includes one of ethyl formate, propyl formate, isobutyl formate, pentyl formate, ethyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, isoamyl acetate, benzyl acetate, phenyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, butyl butyrate, isobutyl butyrate, isoamyl butyrate, ethyl isobutyrate, ethyl isoamylate, isoamyl isoamylate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, isoamyl benzoate, methyl phenylacetate, ethyl phenylacetate, propyl phenylacetate, butyl phenylacetate, and isoamyl phenylacetate, preferably one of ethyl acetate, butyl acetate, pentyl acetate, and isoamyl acetate;

[0103] And / or, the aromatic hydrocarbon solvent includes one of toluene, ethylbenzene, xylene, and cumene, preferably toluene;

[0104] And / or, the ether solvent includes one of dimethyl ether, methyl ethyl ether, diethyl ether, ethyl propyl ether, dipropyl ether, dibutyl ether, methyl propyl ether, methyl butyl ether, methyl isobutyl ether, methyl tert-butyl ether, methyl isoamyl ether, methyl tert-amyl ether, methyl cyclopentyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, tetrahydrofuran, tetrahydropyran, and 1,4-dioxane, preferably one of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and tetrahydrofuran;

[0105] And / or, the ketone solvent includes one of acetone, butanone, cyclohexanone, methyl isobutyl ketone, and methyl isopropyl ketone, preferably acetone or butanone.

[0106] As a preferred embodiment of the present invention, after the polymerization reaction is completed, it further includes the steps of performing solid-liquid separation on the reaction system and drying the separated copolymer. The solid-liquid separation is carried out by known methods such as filtration, centrifugation, and evaporation of the solvent.

[0107] As an embodiment of the present invention, the molar ratio of the amine compound to the anhydride group contained in the copolymer is 1-50:1;

[0108] And / or, the temperature of the amination reaction is 20 - 100 °C, and the time is 1 - 12 h. The temperature is preferably 20 - 60 °C, and the time is preferably 1 - 6 h.

[0109] As the third aspect of the present invention, the present invention provides the application of the above N, P - based flame retardant in the preparation of flame - retardant polymers.

[0110] As the fourth aspect of the present invention, the present invention provides a flame - retardant polymer composite material. By mass percentage, the raw materials include: 0.1 - 10% of the above N, P - based flame retardant and the balance polymer resin matrix.

[0111] As a preferred embodiment of the present invention, the polymer resin matrix includes polypropylene, epoxy resin + curing agent, thermoplastic polyurethane elastomer, nylon or cyanate resin.

[0112] As the fifth aspect of the present invention, the present invention provides a preparation method of the above flame - retardant polymer composite material, including the following steps:

[0113] Mix the N, P - based flame retardant and the polymer resin matrix, and then form them to obtain the flame - retardant polymer composite material.

[0114] As the sixth aspect of the present invention, the present invention provides the application of the above N, P - based flame retardant or the above flame - retardant polymer composite material in the preparation of flame - retardant materials.

[0115] The technical solutions of the present invention will be further described below in conjunction with specific examples.

[0116] In the specific embodiments of the present invention, if room temperature is involved, it specifically refers to 25 ± 2 °C.

[0117] All raw materials used in the specific embodiments of the present invention are ordinary commercially available products.

[0118] Example 1

[0119] An N, P - based flame retardant, the preparation steps are as follows:

[0120] (1) Preparation of monomer A

[0121] Dissolve 216 g of DOPO and 48 g of furfurylamine in 500 g of methanol, then add 30 g of solid formaldehyde thereto, pass nitrogen for 10 min to remove oxygen, and then place it in an oil bath at 60 °C for reaction for 24 h. After the reaction is completed, after separation, washing, and drying, monomer A is obtained, and the yield is 70%.

[0122] (2) Preparation of copolymer

[0123] Dissolve 200 g of monomer A and 100 g of maleic anhydride in 700 g of ethyl acetate. Add 25 g of azobisisobutyronitrile and stir to dissolve it. Then, purge with nitrogen for 10 min to remove oxygen. Subsequently, place it in an 80 °C oil bath for polymerization reaction for 6 h. After the reaction is completed, through separation, washing, and drying, a copolymer is obtained (the structural formula is as shown in Formula I, where R2 = R3 = H, the number-average molecular weight of the copolymer is 2400 g / mol, n1 = 2, n2 = 4, n3 = 2, n4 = 0), which is the N, P-based flame retardant.

[0124] Figure 1 1H NMR and 13C NMR spectra of monomer A prepared in step (1) of this example Figure 2 1H NMR spectrum of the copolymer prepared in step (2) of this example, which proves the successful preparation of monomer A and the copolymer.

[0125] Example 2

[0126] An N, P-based flame retardant is prepared according to the following steps:

[0127] (1) Preparation of monomer A

[0128] Dissolve 216 g of DOPO and 32 g of furfurylamine in 500 g of ethanol. Then add 20 g of solid formaldehyde. Purge with nitrogen for 10 min to remove oxygen. Subsequently, place it in a 75 °C oil bath for reaction for 2 h. After the reaction is completed, through separation, washing, and drying, monomer A is obtained with a yield of 90%.

[0129] (2) Preparation of copolymer

[0130] Dissolve 200 g of monomer A and 90 g of itaconic anhydride in 700 g of toluene. Add 20 g of azobisisoheptonitrile and stir to dissolve it. Then, purge with nitrogen for 10 min to remove oxygen. Subsequently, place it in a 60 °C oil bath for polymerization reaction for 12 h. After the reaction is completed, through separation, washing, and drying, a copolymer is obtained.

[0131] (3) Preparation of aminated copolymer

[0132] Under closed conditions and at a temperature of 20 °C, introduce ammonia gas into 250 g of the copolymer (containing 0.1 mol of acid anhydride groups) for 1 h (flow rate: 1 L / min). After the gas introduction is completed, an aminated copolymer is obtained (the structural formula is as shown in Formula II, where R2 = R3 = R4 = R5 = H, the number-average molecular weight of the aminated copolymer is 2500 g / mol, n1 = 3, n2 = 0, n3 = 1, n4 = 5), which is the N, P-based flame retardant.

[0133] Figure 3FTIR spectra of monomer A prepared in step (1), the copolymer prepared in step (2), and the aminated copolymer prepared in step (3) of this example (where the comonomer represents monomer A). It can be seen from Figure 3 that the copolymer shows characteristic peaks of anhydride groups at 1780 cm -1 and 1860 cm -1 , which proves the synthesis of the copolymer. After the amination reaction, the characteristic peaks of anhydride groups at 1780 cm -1 and 1860 cm -1 disappear, and characteristic infrared peaks of amide appear at 1712 cm -1 in the aminated copolymer, which proves the successful preparation of the aminated copolymer.

[0134] Example 3

[0135] An N, P-based flame retardant is prepared according to the following steps:

[0136] (1) Preparation of monomer A

[0137] Dissolve 216 g of DOPO and 40 g of furfurylamine in 500 g of acetone, then add 30 g of solid formaldehyde thereto, purge with nitrogen for 10 min to remove oxygen, and then place it in an oil bath at 30 °C for reaction for 48 h. After the reaction is completed, after separation, washing, and drying, monomer A is obtained with a yield of 50%.

[0138] (2) Preparation of the copolymer

[0139] Dissolve 200 g of monomer A, 40 g of itaconic anhydride, and 40 g of maleic anhydride in 700 g of butanone, add 15 g of benzoyl peroxide, stir to dissolve it, purge with nitrogen for 10 min to remove oxygen, and then place it in an oil bath at 90 °C for polymerization reaction for 2 h. After the reaction is completed, after separation, washing, and drying, a copolymer (the structural formula is shown in Formula I, where R2 = R3 = H, the number-average molecular weight of the copolymer is 3700 g / mol, n1 = 4, n2 = 4, n3 = 8, n4 = 8) is obtained, which is the N, P-based flame retardant.

[0140] Example 4

[0141] An N, P-based flame retardant is prepared according to the following steps:

[0142] (1) Preparation of monomer A

[0143] Dissolve 216 g of DOPO and 35 g of furfurylamine in 500 g of tetrahydrofuran, then add 25 g of solid formaldehyde thereto, purge with nitrogen for 10 min to remove oxygen, and then place it in an oil bath at 75 °C for reaction for 2 h. After the reaction is completed, after separation, washing, and drying, monomer A is obtained with a yield of 95%.

[0144] (2) Preparation of Copolymer

[0145] Dissolve 200 g of monomer A and 70 g of maleic anhydride in 700 g of ethylene glycol dimethyl ether. Add 10 g of azobisisobutyronitrile, stir to dissolve it, then pass nitrogen for 10 min to remove oxygen, and then place it in an oil bath at 70 °C for polymerization reaction. The reaction time is 10 h. After the reaction is completed, after separation, washing, and drying, a copolymer is obtained.

[0146] (3) Preparation of Aminated Copolymer

[0147] Under closed conditions, add 30 g of ethylenediamine to 250 g of copolymer (containing 0.1 mol of anhydride groups), and carry out amination reaction at 50 °C. The reaction time is 12 h. After the reaction is completed, after separation, washing, and drying, an aminated copolymer (the structural formula is as shown in Formula II, where R2 = R3 = R4 = H, R5 = -(CH2)2NH2, the number-average molecular weight of the aminated copolymer is 2500 g / mol, n1 = 2, n2 = 4, n3 = 2, n4 = 0) is obtained, which is the N, P series flame retardant.

[0148] Example 5

[0149] An N, P series flame retardant, the preparation steps are as follows:

[0150] (1) Preparation of Monomer A

[0151] Dissolve 216 g of DOPO and 45 g of furfurylamine in 500 g of water, then add 90 g of formaldehyde aqueous solution (concentration 37 wt%), pass nitrogen for 10 min to remove oxygen, and then place it in an oil bath at 80 °C for reaction for 1 h. After the reaction is completed, after separation, washing, and drying, monomer A is obtained, and the yield is 60%.

[0152] (2) Preparation of Copolymer

[0153] Dissolve 200 g of monomer A and 60 g of itaconic anhydride in 700 g of butyl acetate. Add 5 g of diisopropylbenzene peroxide, stir to dissolve it, then pass nitrogen for 10 min to remove oxygen, and then place it in an oil bath at 120 °C for polymerization reaction. The reaction time is 10 h. After the reaction is completed, after separation, washing, and drying, a copolymer (the structural formula is as shown in Formula I, where R2 = R3 = H, the number-average molecular weight of the copolymer is 13000 g / mol, n1 = 9, n2 = 0, n3 = 9, n4 = 30) is obtained, which is the N, P series flame retardant.

[0154] Example 6

[0155] An N, P series flame retardant, the preparation steps are as follows:

[0156] (1) Preparation of Monomer A

[0157] Dissolve 216 g of DOPO and 42 g of furfurylamine in 500 g of methyl ethyl ketone, then add 90 g of aqueous formaldehyde solution (concentration: 37 wt%), purge with nitrogen for 10 min to remove oxygen, and then place it in an oil bath at 70 °C for reaction for 10 h. After the reaction is completed, after separation, washing, and drying, monomer A is obtained with a yield of 65%.

[0158] (2) Preparation of copolymer

[0159] Dissolve 200 g of monomer A and 50 g of maleic anhydride in 700 g of ethylene glycol diethyl ether, add 1 g of diisopropylbenzene peroxide, stir to dissolve it, purge with nitrogen for 10 min to remove oxygen, and then place it in an oil bath at 120 °C for polymerization reaction. The reaction time is 6 h. After the reaction is completed, after separation, washing, and drying, a copolymer is obtained.

[0160] (3) Preparation of aminated copolymer

[0161] Under closed conditions, add 50 g of butanediamine to 250 g of copolymer (containing 0.4 mol of anhydride groups), carry out amination reaction at 30 °C, and the reaction time is 6 h. After the reaction is completed, after separation, washing, and drying, an aminated copolymer (the structural formula is as shown in Formula II, where R2 = R3 = R4 = H, R5 = -(CH2)4NH2, the number-average molecular weight of the aminated copolymer is 30000 g / mol, n1 = 10, n2 = 50, n3 = 30, n4 = 0) is obtained, which is the N, P-based flame retardant.

[0162] Example 7

[0163] An N, P-based flame retardant, the preparation steps are as follows:

[0164] (1) Preparation of monomer A

[0165] Dissolve 216 g of DOPO and 36 g of furfurylamine in 500 g of ethanol, then add 90 g of aqueous formaldehyde solution (concentration: 37 wt%), purge with nitrogen for 10 min to remove oxygen, and then place it in an oil bath at 65 °C for reaction for 8 h. After the reaction is completed, after separation, washing, and drying, monomer A is obtained with a yield of 90%.

[0166] (2) Preparation of copolymer

[0167] Dissolve 200 g of monomer A and 40 g of maleic anhydride in 700 g of butyl acetate. Add 12 g of azobisisoheptonitrile, stir to dissolve it, then purge with nitrogen for 10 min to remove oxygen. Then place it in an oil bath at 45 °C for polymerization reaction. The reaction time is 12 h. After the reaction is completed, through separation, washing, and drying, a copolymer is obtained (the structural formula is as shown in Formula I, where R2 = R3 = H, the number-average molecular weight of the copolymer is 4800 g / mol, n1 = 4, n2 = 8, n3 = 4, n4 = 0), which is the N, P-based flame retardant.

[0168] Example 8

[0169] An N, P-based flame retardant, the preparation steps are as follows:

[0170] (1) Preparation of monomer A

[0171] Dissolve 216 g of DOPO and 44 g of furfurylamine in 500 g of methanol. Then add 90 g of formaldehyde aqueous solution (concentration 37 wt%) to it. Purge with nitrogen for 10 min to remove oxygen. Then place it in an oil bath at 56 °C for reaction for 24 h. After the reaction is completed, through separation, washing, and drying, monomer A is obtained, and the yield is 70%.

[0172] (2) Preparation of copolymer

[0173] Dissolve 200 g of monomer A, 15 g of itaconic anhydride, and 15 g of maleic anhydride in 700 g of ethylene glycol diethyl ether. Add 17 g of azobisisoheptonitrile, stir to dissolve it, then purge with nitrogen for 10 min to remove oxygen. Then place it in an oil bath at 51 °C for polymerization reaction. The reaction time is 10 h. After the reaction is completed, through separation, washing, and drying, a copolymer is obtained.

[0174] (3) Preparation of aminated copolymer

[0175] Under closed conditions, add 80 g of sebac diamine to 250 g of copolymer (containing 0.1 mol of acid anhydride groups), and carry out amination reaction at 100 °C. The reaction time is 3 h. After the reaction is completed, through separation, washing, and drying, an aminated copolymer is obtained (the structural formula is as shown in Formula II, where R2 = R3 = R4 = H, R5 = -(CH2) 10 NH2, the number-average molecular weight of the aminated copolymer is 5000 g / mol, n1 = 4, n2 = 8, n3 = 4, n4 = 8), which is the N, P-based flame retardant.

[0176] Example 9

[0177] An N, P-based flame retardant, the preparation steps are as follows:

[0178] (1) Preparation of monomer A

[0179] Dissolve 216 g of DOPO and 37 g of furfurylamine in 500 g of acetone. Then add 27 g of solid formaldehyde thereto, purge with nitrogen for 10 min to remove oxygen, and then place it in an oil bath at 43 °C for reaction for 10 h. After the reaction is completed, after separation, washing, and drying, monomer A is obtained with a yield of 50%.

[0180] (2) Preparation of copolymer

[0181] Dissolve 200 g of monomer A and 20 g of maleic anhydride in 700 g of butyl acetate, add 8 g of azobisisobutyronitrile, stir to dissolve it, purge with nitrogen for 10 min to remove oxygen, and then place it in an oil bath at 85 °C for polymerization reaction. The reaction time is 1 h. After the reaction is completed, after separation, washing, and drying, a copolymer (the structural formula is as shown in Formula I, where R2 = R3 = H, the number-average molecular weight of the copolymer is 1200 g / mol, n1 = 1, n2 = 2, n3 = 1, n4 = 0) is obtained, which is the N, P-based flame retardant.

[0182] Example 10

[0183] An N, P-based flame retardant, the preparation steps are as follows:

[0184] (1) Preparation of monomer A

[0185] Dissolve 216 g of DOPO and 36 g of furfurylamine in 500 g of tetrahydrofuran. Then add 25 g of solid formaldehyde thereto, purge with nitrogen for 10 min to remove oxygen, and then place it in an oil bath at 62 °C for reaction for 4 h. After the reaction is completed, after separation, washing, and drying, monomer A is obtained with a yield of 95%.

[0186] (2) Preparation of copolymer

[0187] Dissolve 200 g of monomer A and 10 g of itaconic anhydride in 700 g of ethylene glycol diethyl ether, add 2 g of azobisisobutyronitrile, stir to dissolve it, purge with nitrogen for 10 min to remove oxygen, and then place it in an oil bath at 72 °C for polymerization reaction. The reaction time is 12 h. After the reaction is completed, after separation, washing, and drying, a copolymer is obtained.

[0188] (3) Preparation of aminated copolymer

[0189] Under closed conditions, add 70 g of hexamethylenediamine to 250 g of copolymer (containing 0.1 mol of anhydride groups), carry out amination reaction at 60 °C, and the reaction time is 5 h. After the reaction is completed, after separation, washing, and drying, an aminated copolymer (the structural formula is as shown in Formula II, where R2 = R3 = R4 = H, R5 = -(CH2)6NH2, the number-average molecular weight of the aminated copolymer is 2700 g / mol, n1 = 2, n2 = 0, n3 = 2, n4 = 4) is obtained, which is the N, P-based flame retardant.

[0190] Application Example 1

[0191] A flame-retardant polymer composite material is prepared as follows:

[0192] Take 97.5 g of polypropylene (PP) and 2.5 g of copolymer (prepared in Example 1), and blend them through a kneader. The temperature of the kneader is set at 175 °C, the rotation speed is 75 rpm, and the kneading time is 6 min. Then, use a flat vulcanizer to press and sample (i.e., form, and the sample size is determined according to the test requirements) to obtain a flame-retardant polymer composite material, denoted as PP-1.

[0193] Application Example 2

[0194] A flame-retardant polymer composite material is prepared as follows:

[0195] Take 95 g of polypropylene and 5 g of copolymer (prepared in Example 1), and blend them through a kneader. The temperature of the kneader is set at 175 °C, the rotation speed is 75 rpm, and the kneading time is 6 min. Then, use a flat vulcanizer to press and sample to obtain a flame-retardant polymer composite material, denoted as PP-2.

[0196] Application Example 3

[0197] A flame-retardant polymer composite material is prepared as follows:

[0198] Take 92.5 g of polypropylene and 7.5 g of copolymer (prepared in Example 1), and blend them through a kneader. The temperature of the kneader is set at 175 °C, the rotation speed is 75 rpm, and the kneading time is 6 min. Then, use a flat vulcanizer to press and sample to obtain a flame-retardant polymer composite material, denoted as PP-3.

[0199] Application Example 4

[0200] A flame-retardant polymer composite material is prepared as follows:

[0201] Take 90 g of polypropylene and 10 g of copolymer (prepared in Example 1), and blend them through a kneader. The temperature of the kneader is set at 175 °C, the rotation speed is 75 rpm, and the kneading time is 6 min. Then, use a flat vulcanizer to press and sample to obtain a flame-retardant polymer composite material, denoted as PP-4.

[0202] Comparative Application Example 1

[0203] A flame-retardant polymer composite material is prepared as follows:

[0204] Take 95 g of polypropylene and 5 g of monomer A (prepared in step (1) of Example 1), and blend them using a Banbury mixer. The temperature of the Banbury mixer is set at 175 °C, the rotation speed is 75 rpm, and the mixing time is 6 min. Then, use a flat vulcanizer to press and sample to obtain a flame-retardant polymer composite, denoted as #PP.

[0205] Comparative Application Example 2

[0206] Preparation of pure polypropylene, steps are as follows:

[0207] Take 100 g of polypropylene and conduct mixing in a Banbury mixer. The temperature of the Banbury mixer is set at 175 °C, the rotation speed is 75 rpm, and the mixing time is 6 min. Then, use a flat vulcanizer to press and sample to obtain a pure polypropylene material, denoted as PP.

[0208] Test Example 1

[0209] Conduct UL-94 tests (refer to "ASTM D3801-2010", the same below) on the flame-retardant polymer (PP) composites prepared in Application Examples 1-4 and Comparative Application Example 1, as well as pure PP. The test results are shown in Table 1.

[0210] Table 1

[0211]

[0212] Note a: The burning time of the sample when ignited twice respectively. Among them, t1 is the afterglow time for the first time, and t2 is the afterglow time for the second time; b: Whether there are molten drops generated during the combustion process and whether the cotton wool below is ignited; c: UL-94 test grade; d: No grade; e: The afterglow for the second time does not self-extinguish.

[0213] As can be seen from Table 1, adding 5% of the copolymer to PP can reach the V-0 grade, while when replacing the copolymer with monomer A in #PP, the UL-94 test grade can only reach V-2. The reason is that when adding the copolymer, the anhydride group plays a role in promoting char formation during the combustion process, and the DOPO group plays a role in gas-phase flame retardancy. The two work together, and the flame-retardant effect is better. When adding monomer A, without the action of the anhydride group, the char-forming ability is insufficient, and at the same time, a large amount of molten drops will be generated during the combustion of PP, thus causing the molten drops to ignite the cotton wool below.

[0214] Application Example 5

[0215] A flame-retardant polymer composite, the preparation steps are as follows:

[0216] After thoroughly mixing 100 g of epoxy resin (E-51) and 1 g of aminated copolymer (prepared in Example 2) at 80 °C, 30 g of DDM (diaminodiphenylmethane) was added. After the DDM was dissolved, it was poured into a mold and pre-cured at 80 °C for 2 h, and then cured at 150 °C for 4 h to form a flame-retardant polymer composite, denoted as EP-1.

[0217] Application Example 6

[0218] A flame-retardant polymer composite is prepared as follows:

[0219] After thoroughly mixing 100 g of epoxy resin and 1 g of aminated copolymer (prepared in Example 4) at 80 °C, 30 g of DDM (diaminodiphenylmethane) was added. After the DDM was dissolved, it was poured into a mold and pre-cured at 80 °C for 2 h, and then cured at 150 °C for 4 h to form a flame-retardant polymer composite, denoted as EP-2.

[0220] Application Example 7

[0221] A flame-retardant polymer composite is prepared as follows:

[0222] After thoroughly mixing 100 g of epoxy resin and 1 g of aminated copolymer (prepared in Example 6) at 80 °C, 30 g of DDM (diaminodiphenylmethane) was added. After the DDM was dissolved, it was poured into a mold and pre-cured at 80 °C for 2 h, and then cured at 150 °C for 4 h to form a flame-retardant polymer composite, denoted as EP-3.

[0223] Application Example 8

[0224] A flame-retardant polymer composite is prepared as follows:

[0225] After thoroughly mixing 100 g of epoxy resin and 1 g of aminated copolymer (prepared in Example 8) at 80 °C, 30 g of DDM (diaminodiphenylmethane) was added. After the DDM was dissolved, it was poured into a mold and pre-cured at 80 °C for 2 h, and then cured at 150 °C for 4 h to form a flame-retardant polymer composite, denoted as EP-4.

[0226] Comparative Application Example 3

[0227] The preparation of pure epoxy resin material is as follows:

[0228] 100 g of epoxy resin was heated to 80 °C, 30 g of DDM (diaminodiphenylmethane) was added. After the DDM was dissolved, it was poured into a mold and pre-cured at 80 °C for 2 h, and then cured at 150 °C for 4 h to form a pure epoxy resin material, denoted as EP.

[0229] Comparative Application Example 4

[0230] A flame-retardant polymer composite material is prepared according to the following steps:

[0231] After 100 g of epoxy resin and 1 g of monomer A (prepared in step (1) of Example 2) are fully mixed at 80 °C, 30 g of DDM (diaminodiphenylmethane) is added. After the DDM is dissolved, it is poured into a mold and pre-cured at 80 °C for 2 h, and then cured at 150 °C for 4 h to form a flame-retardant polymer composite material, denoted as #EP.

[0232] Test Example 2

[0233] The flame-retardant polymer (EP) composite materials prepared in Application Examples 5-8, the comparative application example 4, and the pure EP prepared in comparative application example 3 were subjected to UL-94 tests and impact strength tests (refer to "GB / T 1043.1 2008", the same below), and the test results are shown in Table 2 and Figure 4 as follows.

[0234] Table 2

[0235]

[0236]

[0237] Note: d is the notched impact strength of a simply supported beam.

[0238] Figure 4 are the vertical burning test results (photos during the burning process, where the time does not include the time for igniting the sample) of the flame-retardant polymer (EP) composite materials prepared in Application Examples 5-8 and the pure EP (comparative application example 3). As can be seen from Table 2 and Figure 4 it can be seen that the pure EP does not self-extinguish after being ignited. After adding a small amount of aminated copolymer to it, it can reach the V-0 grade, with a small addition amount and high flame-retardant efficiency. In addition, the impact strength has also been enhanced to varying degrees, achieving a toughening effect. However, after only adding monomer A, due to the lack of an acid source in the flame retardant (the remaining carboxyl groups in the aminated polymer can act as an acid source to promote the charring efficiency of the resin during combustion), the charring ability is poor, and it can only reach the V-1 grade. Moreover, there is a lack of interaction between monomer A and the epoxy resin matrix after curing, resulting in a decrease in the impact strength of #EP.

[0239] Application Example 9

[0240] A flame-retardant polymer composite material is prepared according to the following steps:

[0241] Take 99.9 g of thermoplastic polyurethane elastomer (TPU) and 0.1 g of copolymer (prepared in Example 3), and blend them through a Banbury mixer. The temperature of the Banbury mixer is set at 185 °C, the rotation speed is 75 rpm, and the mixing time is 6 min. Then, use a flat vulcanizer to press and sample to obtain a flame-retardant polymer composite, denoted as TPU-1.

[0242] Application Example 10

[0243] A flame-retardant polymer composite, the preparation steps are as follows:

[0244] Take 99.5 g of TPU and 0.5 g of copolymer (prepared in Example 5), and blend them through a Banbury mixer. The temperature of the Banbury mixer is set at 185 °C, the rotation speed is 75 rpm, and the mixing time is 6 min. Then, use a flat vulcanizer to press and sample to obtain a flame-retardant polymer composite, denoted as TPU-2.

[0245] Application Example 11

[0246] A flame-retardant polymer composite, the preparation steps are as follows:

[0247] Take 99 g of TPU and 1 g of copolymer (prepared in Example 7), and blend them through a Banbury mixer. The temperature of the Banbury mixer is set at 185 °C, the rotation speed is 75 rpm, and the mixing time is 6 min. Then, use a flat vulcanizer to press and sample to obtain a flame-retardant polymer composite, denoted as TPU-3.

[0248] Application Example 12

[0249] A flame-retardant polymer composite, the preparation steps are as follows:

[0250] Take 98.5 g of TPU and 1.5 g of copolymer (prepared in Example 9), and blend them through a Banbury mixer. The temperature of the Banbury mixer is set at 185 °C, the rotation speed is 75 rpm, and the mixing time is 6 min. Then, use a flat vulcanizer to press and sample to obtain a flame-retardant polymer composite, denoted as TPU-4.

[0251] Test Example 3

[0252] Carry out UL-94 tests on the flame-retardant polymer (TPU) composites prepared in Application Examples 9-12, and the test results are shown in Table 3.

[0253] Table 3

[0254]

[0255] As can be seen from Table 3, adding 1.5% of the copolymer to TPU can reach the V-0 grade. The copolymer has a small addition amount in TPU and high flame-retardant efficiency.

[0256] Application Example 13

[0257] A flame-retardant polymer composite material is prepared as follows:

[0258] Take 98 g of nylon 66 (PA66) and 2 g of the copolymer (prepared in step (2) of Example 2), and blend them through a kneader. The temperature of the kneader is set at 230 °C, the rotation speed is 75 rpm, and the kneading time is 6 min. Then, use a flat vulcanizer to press and sample to obtain the flame-retardant polymer composite material, denoted as PA-1.

[0259] Application Example 14

[0260] A flame-retardant polymer composite material is prepared as follows:

[0261] Take 98 g of nylon 66 (PA66) and 2 g of the aminated copolymer (prepared in step (3) of Example 2), and blend them through a kneader. The temperature of the kneader is set at 230 °C, the rotation speed is 75 rpm, and the kneading time is 6 min. Then, use a flat vulcanizer to press and sample to obtain the flame-retardant polymer composite material, denoted as PA-2.

[0262] Test Example 4

[0263] Perform UL-94 tests on the flame-retardant polymer (PA) composite materials prepared in Application Examples 13-14. The test results are shown in Table 4 and Figure 5 as follows.

[0264] Table 4

[0265]

[0266] Figure 5 are the vertical burning test results (photos during the burning process) of the flame-retardant polymer (PA) composite materials prepared in Application Examples 13-14. As can be seen from Table 4 and Figure 5 it can be known that adding 2% of the copolymer to nylon 66 can only reach the V-1 grade, while adding 2% of the aminated copolymer to nylon 66 can reach the V-0 grade. The reason is that nitrogen elements can release inert gases, such as nitrogen gas, during the combustion process, further reducing the oxygen concentration and inhibiting combustion. Therefore, the aminated copolymer has a small addition amount in nylon 66 and high flame-retardant efficiency.

[0267] Application Example 15

[0268] A flame-retardant polymer composite material is prepared as follows:

[0269] After thoroughly mixing 99 g of cyanate ester resin (CE) and 1 g of copolymer (prepared in Example 10) at 120 °C, pour the mixture into a mold and cure it according to the following procedure: cure at 150 °C for 2 h, 180 °C for 2 h, 200 °C for 2 h, 220 °C for 4 h, and 240 °C for 2 h to obtain a flame-retardant polymer composite, denoted as CE-1.

[0270] Application Example 16

[0271] A method for preparing a flame-retardant polymer composite is as follows:

[0272] After thoroughly mixing 99 g of cyanate ester resin (CE) and 1 g of aminated copolymer (prepared in Example 10) at 120 °C, pour the mixture into a mold and cure it according to the following procedure: cure at 150 °C for 2 h, 180 °C for 2 h, 200 °C for 2 h, 220 °C for 4 h, and 240 °C for 2 h to obtain a flame-retardant polymer composite, denoted as CE-1.

[0273] Comparative Application Example 5

[0274] The preparation of a pure cyanate ester resin material is as follows:

[0275] Heat 100 g of cyanate ester resin (CE) to 120 °C and then pour it into a mold. Cure it according to the following procedure: cure at 150 °C for 2 h, 180 °C for 2 h, 200 °C for 2 h, 220 °C for 4 h, and 240 °C for 2 h to obtain a pure cyanate ester resin material, denoted as CE.

[0276] Test Example 5

[0277] Perform UL-94 tests and impact strength tests on the flame-retardant polymer (CE) composites prepared in Application Examples 15 - 16 and the pure CE prepared in Comparative Application Example 5. The test results are shown in Table 5.

[0278] Table 5

[0279]

[0280] As can be seen from Table 5, adding 1% of the copolymer to the CE resin can achieve the V-0 rating. The copolymer has a small addition amount in the CE resin and a high flame-retardant efficiency.

[0281] The above-described embodiments are only descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A nitrogen and phosphorus-based flame retardant, characterized in that, The molecular structure of the N, P - based flame retardant includes structural unit I and / or structural unit II, and at least one of structural unit III - structural unit IV, or at least one of structural unit V - structural unit VI: wherein, R1 is each of R2 and R3 is independently selected from one of a hydrogen atom and a methyl group; each of R4 and R5 is independently selected from one of a hydrogen atom, an alkyl group having 2 to 10 carbon atoms, and an alkylamine having 2 to 10 carbon atoms.

2. The N, P-based flame retardant according to claim 1, characterized in that, The structural formula of the N, P - based flame retardant is one of Formula I - Formula II: Wherein, n1, n2, n3, and n4 are independently selected from 0 to 50, and are not simultaneously 0.

3. The preparation method of the N, P-based flame retardant according to any one of claims 1-2, characterized in that, It includes the following steps: Dissolve 9,10 - dihydro - 9 - oxa - 10 - phosphaphenanthrene - 10 - oxide, formaldehyde, and furfurylamine in solvent A and carry out a reaction to obtain monomer A; Dissolve the monomer A, an electron - withdrawing monomer, and an initiator in solvent B and carry out a polymerization reaction to obtain a copolymer, which is an N, P - based flame retardant whose molecular structure includes structural unit I and / or structural unit II, and at least one of structural unit III - structural unit IV; Mix the copolymer with an amine compound and carry out an amination reaction to obtain an aminated copolymer, which is an N, P - based flame retardant whose molecular structure includes structural unit I and / or structural unit II, and at least one of structural unit V - structural unit VI; The structural formula of the monomer A is The electron - withdrawing monomer is one or more of the compounds shown in Formula V and Formula VI: wherein, R2 and R3 are each independently selected from one of a hydrogen atom and a methyl group; The structural formula of the amine compound is wherein, R4 and R5 are each independently selected from a hydrogen atom, an alkyl group having 2 to 10 carbon atoms, and an alkylamine having 2 to 10 carbon atoms.

4. The preparation method according to claim 3, characterized in that, The solvent A includes one of water, alcohol solvents, ketone solvents, and ether solvents; And / or, the molar ratio of 9,10 - dihydro - 9 - oxa - 10 - phosphaphenanthrene - 10 - oxide, formaldehyde, and furfurylamine is 2 - 3:2 - 3:1; And / or, the sum of the masses of 9,10 - dihydro - 9 - oxa - 10 - phosphaphenanthrene - 10 - oxide, formaldehyde, and furfurylamine is 0.1 - 70% of the sum of the masses of 9,10 - dihydro - 9 - oxa - 10 - phosphaphenanthrene - 10 - oxide, formaldehyde, furfurylamine, and solvent A; And / or, the temperature of the reaction is 30 - 120 °C and the time is 1 - 48 h.

5. The preparation method according to claim 3, characterized in that, The initiator includes one or more of peroxide initiators and azo initiators; And / or, the solvent B includes one or more of organic acid alkyl esters, aromatic hydrocarbon solvents, ether solvents, and ketone solvents; And / or, the molar ratio of the electron - withdrawing monomer to monomer A is 0.1 - 3:1; And / or, the sum of the masses of the electron - withdrawing monomer and monomer A is 0.1 - 50% of the sum of the masses of monomer A, the electron - withdrawing monomer, the initiator, and solvent B; And / or, the mass of the initiator is 0.0001 - 5% of the sum of the masses of monomer A, the electron - withdrawing monomer, the initiator, and solvent B; And / or, the temperature of the polymerization reaction is 40 - 120 °C and the time is 1 - 12 h.

6. The preparation method according to claim 3, characterized in that, The molar ratio of the amine compound to the anhydride group contained in the copolymer is 1 - 50:1; And / or, the temperature of the amination reaction is 20 - 100 °C and the time is 1 - 12 h.

7. The application of the N, P - based flame retardant according to any one of claims 1 - 2 in the preparation of a flame - retardant polymer.

8. A flame-retardant polymer composite, characterized in that, By mass percentage, the raw materials include: 0.1 - 10% of the N, P - based flame retardant according to any one of claims 1 - 2 and the balance polymer resin matrix.

9. The method for preparing a flame-retardant polymer composite according to claim 8, characterized in that, It includes the following steps: Mix the N, P-based flame retardant and the polymer resin matrix, and then mold to obtain the flame-retardant polymer composite material.

10. Use of the N, P-based flame retardant according to any one of claims 1-2 or the flame-retardant polymer composite material according to claim 8 in the preparation of a flame-retardant material.

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