Flame-retardant epoxy resin composition, flame-retardant epoxy resin cured product, and preparation method and use thereof

Abstract

The application discloses a flame-retardant epoxy resin composition, a flame-retardant epoxy resin cured product and a preparation method and application thereof. The flame-retardant epoxy resin composition comprises the following components in parts by weight: 100 parts by weight of epoxy resin; 10-100 parts by weight of an organic flame retardant; 0-10 parts by weight of an accelerator; 30-260 parts by weight of a curing agent; and 0-50 parts by weight of an epoxy resin diluent. The organic flame retardant is selected from an organic nitrogen-containing flame retardant and an organic phosphorus-containing flame retardant. The specific reactive phosphorus-containing and nitrogen-containing flame retardant used in the application not only has a flame-retardant effect, but also can participate in the curing reaction as an epoxy resin matrix. The flame-retardant epoxy resin prepared by the action of the two has greatly improved the thermal performance and mechanical performance of the product while ensuring that the flame-retardant grade reaches UL94V0 compared with the flame-retardant epoxy resin prepared by adding a flame retardant.

Description

Technical Field

[0001] This invention relates to the technical field of flame-retardant resins, and more specifically, to compositions of flame-retardant epoxy resins, cured flame-retardant epoxy resins, methods for their preparation, and applications. Background Technology

[0002] Epoxy resin (EP), as an important matrix resin in composite materials, possesses excellent physical and chemical properties, especially good adhesive strength, dimensional stability, high hardness, good toughness, resistance to alkalis and most solvents, and good dielectric properties. Therefore, it is widely used in transportation, aerospace, interior decoration, and electronics. However, epoxy resin is a flammable material with a rapid heat release rate and fast flame propagation during combustion, accompanied by the production of toxic gases and dense smoke, limiting its application in composite interior components. With increasing demands for flame retardant performance in daily applications, research on its flame retardant modification is receiving growing attention.

[0003] Currently, flame-retardant epoxy resin systems on the market can be mainly classified into the following categories:

[0004] 1. Epoxy resins containing halogens or epoxy resins with added halogen flame retardants are used. These flame retardants mainly exert a free radical quenching effect in the gas phase during the combustion of the matrix to achieve flame retardant modification. However, the combustion of halogen-containing substances produces acids and dioxins, which cause great harm to the environment and human health. With increasingly stringent environmental protection requirements, this type of flame-retardant epoxy resin is facing elimination.

[0005] 2. Use phosphorus-containing epoxy resin or epoxy resin with added phosphorus-containing flame retardants. Phosphorus-containing flame retardants primarily decompose during the combustion of the matrix to form phosphorus-containing substances such as phosphates and polyphosphates with strong dehydrating properties. This promotes the early dehydration and carbonization of the matrix material, forming a continuous and dense covering layer, reducing the release of combustible substances and limiting the transfer of heat and oxygen. Simultaneously, phosphorus-based flame retardants generate phosphorus-oxygen free radicals through thermal decomposition, quenching the active free radicals produced during the combustion of polymer materials, inhibiting the continued chain reaction, and lowering the combustion temperature.

[0006] 3. Epoxy resins with added nitrogen-containing flame retardants, and phosphorus-containing flame retardants, primarily exert their flame-retardant effect in the gas phase. During thermal decomposition, they absorb a large amount of heat and release non-flammable gases (such as carbon dioxide, nitrogen, ammonia, and water vapor), thereby reducing the surface temperature of the material and the concentration of flammable gases, thus achieving a flame-retardant effect. However, most phosphorus / nitrogen-containing flame retardants are currently solid powders, such as inorganic phosphates, aluminum hydroxide, and melamine salts, with particle sizes typically in the micrometer range. These powders have poor compatibility with epoxy resins, easily leading to insufficient thermomechanical and mechanical properties of the resin matrix. An ideal flame retardant should possess high flame-retardant efficiency, low or even non-toxicity, good compatibility with the matrix, and good tolerance.

[0007] CN109096472A discloses a novel PN-Si synergistic flame-retardant epoxy resin curing agent, comprising adding an appropriate amount of the novel PN-Si synergistic flame-retardant epoxy resin curing agent to epoxy resin, mixing evenly, and then molding, curing, and post-curing to obtain a cured epoxy resin system. This novel curing agent can both cure epoxy resin and be used for flame retardant epoxy resin, and exhibits good curing effect and compatibility.

[0008] CN106633673A discloses a flame-retardant epoxy resin based on a compound of phosphaphenanthrene derivatives and inorganic flame retardants. The method involves compounding different phosphaphenanthrene derivative flame retardants with different inorganic flame retardants, then melt-blending them with bisphenol A diglycidyl ether epoxy resin at a specific temperature. An organic solvent is added to obtain the flame-retardant epoxy resin. A curing agent is then added to the epoxy resin, and the curing reaction is completed at a specific temperature. This method only requires stirring to uniformly mix the flame retardant and epoxy resin, without requiring a chemical bonding reaction between the two, making it simple and easy to implement. The flame-retardant-modified epoxy resin exhibits excellent flame-retardant properties, with a limiting oxygen index reaching 36.9% and a flame retardant rating reaching UL94-V0.

[0009] However, the addition of flame retardants to epoxy resin in the existing technology still greatly reduces the mechanical and thermal properties of epoxy resin. Therefore, there is a need for a method that can improve the flame retardant properties of epoxy resin while maintaining or further improving its mechanical and thermal properties. Summary of the Invention

[0010] To address the problems in existing technologies, this invention proposes a flame-retardant epoxy resin composition, a flame-retardant epoxy resin cured product, its preparation method, and its applications. This invention employs specific reactive phosphorus- and nitrogen-containing flame retardants, which not only provide flame retardancy but also participate in the curing reaction as part of the epoxy resin matrix. The flame-retardant epoxy resin prepared by this interaction, compared to flame-retardant epoxy resins prepared with additive flame retardants, significantly improves the product's thermal and mechanical properties while maintaining a UL94V0 flame retardancy rating.

[0011] To address the aforementioned technical problems, the present invention proposes the following technical solution:

[0012] One object of the present invention is to provide a flame-retardant epoxy resin composition, comprising, by weight, the following substances:

[0013]

[0014] The organic flame retardant is selected from organic nitrogen-containing flame retardants and organic phosphorus-containing flame retardants.

[0015] In the flame-retardant epoxy resin composition of the present invention, preferably,

[0016] Based on the total weight of epoxy resin and organic flame retardant as 100%,

[0017] The organic nitrogen-containing flame retardant accounts for 5% to 25% by mass; preferably 5% to 22.5%.

[0018] The organic phosphorus-containing flame retardant accounts for 5% to 25% of the total mass; preferably 5% to 22.5%.

[0019] More preferably, the organic flame retardant accounts for 25% to 45% of the total weight of epoxy resin and organic flame retardant, which is 100% of the total weight.

[0020] In the flame-retardant epoxy resin composition of the present invention, preferably,

[0021] Accelerator 0-6 parts by weight; and / or,

[0022] 40-240 parts by weight of curing agent; and / or,

[0023] Epoxy resin diluent: 0-40 parts by weight;

[0024] The organic nitrogen-containing flame retardant is 6-40 parts by weight; for example, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40 parts by weight, or any range of any two of the above values.

[0025] The organic phosphorus-containing flame retardant has a mass of 6-40 parts by weight; for example, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40 parts by weight, or any range of any two of the above values.

[0026] In the flame-retardant epoxy resin composition of the present invention, preferably,

[0027] The epoxy resin is selected from at least one of glycidyl ether epoxy resin, glycidyl ester epoxy resin, and glycidyl amine epoxy resin;

[0028] Preferably,

[0029] The glycidyl ether epoxy resin is selected from at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, and phenolic epoxy resin; and / or,

[0030] The glycidyl ester epoxy resin is selected from at least one of 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester and 2,3-epoxypropyl methacrylate.

[0031] More preferably,

[0032] The epoxy value of the epoxy resin is 0.10 to 1.00 mol / 100g.

[0033] In the flame-retardant epoxy resin composition of the present invention, preferably,

[0034] The organic nitrogen-containing flame retardant is selected from triglycidyl isocyanurate; and / or,

[0035] The organic phosphorus-containing flame retardant is selected from triglycidyl phosphate.

[0036]

[0037] The organic flame retardant in this invention can participate in the curing reaction as an epoxy matrix, which greatly improves the flame retardant effect, mechanical and thermal properties; while general nitrogen-containing and phosphorus-containing flame retardants only play a flame retardant role in the system.

[0038] In the flame-retardant epoxy resin composition of the present invention, preferably,

[0039] The accelerator is selected from at least one of quaternary ammonium salts, quaternary phosphate salts, imidazoles and their derivatives;

[0040] Preferably,

[0041] The quaternary ammonium salt is selected from at least one of benzyltriethylammonium bromide and tetraethylammonium bromide; and / or,

[0042] The quaternary phosphorus salt is selected from at least one of methyltriphenylphosphine bromide, ethyltriphenylphosphine bromide, and butyltriphenylphosphine bromide; and / or

[0043] The imidazole derivative is selected from at least one of dimethylimidazole and diethyltetramethylimidazole.

[0044] In the flame-retardant epoxy resin composition of the present invention, preferably,

[0045] The curing agent is selected from at least one of acid anhydride curing agents and amine curing agents;

[0046] Preferably,

[0047] The anhydride curing agent is selected from at least one of methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, and maleic anhydride; and / or,

[0048] The amine curing agent is selected from at least one of dicyandiamide, isophorone diamine, triethylenetetramine, polyetheramine, and 3,3′-dimethyl-4,4′-diamino-dicyclohexylmethane.

[0049] In the flame-retardant epoxy resin composition of the present invention, preferably,

[0050] The epoxy resin diluent is selected from at least one of glycidyl ether diluents; preferably at least one of ethylene glycol diglycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, glycerol triglycidyl ether, and pentaerythritol tetraglycidyl ether.

[0051] A second objective of this invention is to provide a method for preparing a flame-retardant epoxy resin composition according to any one of the objectives of this invention, comprising the following steps:

[0052] An epoxy resin, an organic flame retardant, an optional accelerator, a curing agent, and an optional epoxy resin diluent are mixed evenly to obtain a flame-retardant epoxy resin composition.

[0053] In the preparation method of the flame-retardant epoxy resin composition of the present invention, preferably, the following steps are included:

[0054] (1) Heat and melt epoxy resin and optionally epoxy resin diluent to obtain a melt;

[0055] (2) Add the organic nitrogen-containing flame retardant to the melt from step (1) and mix evenly to obtain a mixture;

[0056] (3) Heat the curing agent and optionally add the accelerator, then mix thoroughly;

[0057] (4) Mix the mixture obtained in step (2) and the substance obtained in step (3) with the organic phosphorus flame retardant to obtain a flame retardant epoxy resin composition.

[0058] In this invention, steps (2) and (3) simply represent corresponding steps and there is no specific order requirement.

[0059] In the preparation method of the flame-retardant epoxy resin composition of the present invention, preferably, in step (1), the mixture is heated to 90-150°C to melt, and preferably held at that temperature for 15-30 minutes after melting; and / or,

[0060] Step (2), the temperature during uniform mixing is 90-150℃; mechanical stirring is preferred for uniform mixing, and the mixing time is further preferred to be 30-60 min; and / or,

[0061] Step (3), the temperature during uniform mixing is 90-150℃; mechanical stirring is preferred for uniform mixing, and the mixing time is further preferred to be 30-60 min; and / or,

[0062] In step (4), the temperature during uniform mixing is 20-60℃; mechanical stirring is preferred for uniform mixing, and the mixing time is further preferred to be 2-5 min.

[0063] A third objective of this invention is to provide a flame-retardant epoxy resin cured product prepared by curing a composition comprising a flame-retardant epoxy resin as described in any one of the objectives of this invention or a flame-retardant epoxy resin prepared by any one of the methods described in any one of the objectives of this invention. Preferably, the flame-retardant rating of the flame-retardant epoxy resin cured product is UL94-V0 or higher.

[0064] The fourth objective of this invention is to provide an application of a flame-retardant epoxy resin composition according to any one of the objectives of this invention, or a flame-retardant epoxy resin composition prepared by any one of the methods according to any one of the objectives of this invention, or a flame-retardant epoxy resin cured product according to any one of the objectives of this invention in flame retardancy.

[0065] The triglycidyl phosphate (TGP) of the present invention can be purchased directly or prepared using existing methods. Preferably, the preparation method of the TGP includes the following steps: The synthetic route of the TGP is as follows:

[0066]

[0067] The method for preparing triglycidyl phosphate (TGP) includes the following steps:

[0068] (1) Add glycidol, phosphorus oxychloride and toluene into the reactor, and add triethylamine, an acid-binding agent, dropwise at 0-4℃;

[0069] (2) After reacting for 16-20 hours, the reaction solution is filtered to remove triethylamine hydrochloride;

[0070] (3) After the filtrate is passed through a rotary evaporator to remove the solvent and unreacted substances, the product triglycidyl phosphate is obtained.

[0071] In some preferred embodiments of the present invention, the molar ratio of glycidol, phosphorus oxychloride, and triethylamine is (3.4–4.2):(3.8–4.2):1.

[0072] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In the following, various technical solutions can, in principle, be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0073] Compared with the prior art, the present invention has at least the following advantages:

[0074] This invention employs specific reactive phosphorus- and nitrogen-containing flame retardants, which not only have flame-retardant effects but also participate in the curing reaction as an epoxy resin matrix. The flame-retardant epoxy resin prepared by the interaction of these two agents, compared with the flame-retardant epoxy resin prepared by additive flame retardants, not only ensures that the flame retardant rating reaches UL94V0 but also greatly improves the thermal and mechanical properties of the product. Detailed Implementation

[0075] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0076] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0077] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0078] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0079] Test method:

[0080] 1. Tensile strength

[0081] The tensile strength of the cured resin was tested on an Instron universal testing machine according to ASTM D638 standard at a tensile rate of 5 mm / min. The results are shown in Table 1.

[0082] 2. Thermodynamic properties

[0083] The glass transition temperature of the cured resin was determined using a TA Instruments Q800 dynamic mechanical property analyzer. The test was conducted in single-cantilever mode under ambient air conditions, with a heating rate of 3°C / min. The temperature measurement range was RT to 250°C. The peak temperature of tano' was selected as the glass transition temperature (Tglass transition temperature) of the cured resin. g The results are shown in Table 1.

[0084] 3. Flame retardant effect test

[0085] The flame retardancy rating of the flame retardant resin samples was tested according to the UL94 standard, and the results are shown in Table 1.

[0086]

Example 1

[0087] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0088]

[0089] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0090] (1) Heat 60g of bisphenol A epoxy resin to 100℃ and keep it warm for 15min;

[0091] (2) Add 20g of triglycidyl isocyanurate, stir mechanically for 60min, and then cool for later use;

[0092] (3) Heat 120g of methyltetrahydrophthalic anhydride to 100℃, add 3g of ethyltriphenylphosphine bromide, stir mechanically for 60min, and then cool down for later use.

[0093] (4) Mix the products obtained from (2) and (3) with 20g of triglycidyl phosphate at 20°C for 3min, and the resulting composition is ready for use.

[0094]

Example 2

[0095] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0096]

[0097] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0098] (1) Heat 60g of bisphenol A epoxy resin to 100℃ and keep it warm for 15min;

[0099] (2) Add 20g of triglycidyl isocyanurate, stir mechanically for 60min, and then cool for later use;

[0100] (3) Heat 130g of methylnadic anhydride to 110℃, add 3g of ethyltriphenylphosphine bromide, stir mechanically for 60min, and then cool down for later use.

[0101] (4) Mix the products obtained from (2) and (3) with 20g of triglycidyl phosphate at 20°C for 4min, and the resulting composition is ready for use.

[0102]

Example 3

[0103] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0104]

[0105] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0106] (1) Heat 50g of bisphenol A epoxy resin and 10g of ethylene glycol diglycidyl ether to 100℃ and keep warm for 15min;

[0107] (2) Add 20g of triglycidyl isocyanurate, stir mechanically for 60min, and then cool for later use;

[0108] (3) Heat 120g of methyltetrahydrophthalic anhydride to 100℃, add 3g of ethyltriphenylphosphine bromide, stir mechanically for 60min, and then cool down for later use.

[0109] (4) Mix the products obtained from (2) and (3) with 20g of triglycidyl phosphate at 20°C for 3min, and the resulting composition is ready for use.

[0110]

Example 4

[0111] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0112]

[0113]

[0114] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0115] (1) Heat 75g of bisphenol A epoxy resin to 100℃ and keep it warm for 15min;

[0116] (2) Add 5g of triglycidyl isocyanurate, stir mechanically for 30 minutes, and then cool down for later use;

[0117] (3) Heat 120g of methyltetrahydrophthalic anhydride to 100℃, add 3g of ethyltriphenylphosphine bromide, stir mechanically for 60min, and then cool down for later use.

[0118] (4) Mix the products obtained from (2) and (3) with 20g of triglycidyl phosphate at 25°C for 3min, and set aside the resulting composition.

[0119]

Example 5

[0120] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0121]

[0122] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0123] (1) Heat 75g of bisphenol A epoxy resin to 100℃ and keep it warm for 15min;

[0124] (2) Add 20g of triglycidyl isocyanurate, stir mechanically for 30 minutes, and then cool down for later use;

[0125] (3) Heat 120g of methyltetrahydrophthalic anhydride to 100℃, add 3g of ethyltriphenylphosphine bromide, stir mechanically for 60min, and then cool down for later use.

[0126] (4) Mix the products obtained from (2) and (3) with 5g of triglycidyl phosphate at 25°C for 3min, and set aside the resulting composition.

[0127]

Example 6

[0128] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0129]

[0130] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0131] (1) Heat 60g of phenolic epoxy resin to 120℃ and keep it warm for 20min;

[0132] (2) Add 20g of triglycidyl isocyanurate, stir mechanically for 30 minutes, and then cool down for later use;

[0133] (3) Heat 120g of methyltetrahydrophthalic anhydride to 100℃, add 3g of ethyltriphenylphosphine bromide, stir mechanically for 60min, and then cool down for later use.

[0134] (4) Mix the products obtained from (2) and (3) with 20g of triglycidyl phosphate at 30°C for 3min, and the resulting composition is ready for use.

[0135]

Example 7

[0136] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0137]

[0138] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0139] (1) Heat 60g of bisphenol F epoxy resin to 110℃ and keep it warm for 20min;

[0140] (2) Add 20g of triglycidyl isocyanurate, stir mechanically for 30 minutes, and then cool down for later use;

[0141] (3) Heat 120g of methyltetrahydrophthalic anhydride to 100℃, add 3g of ethyltriphenylphosphine bromide, stir mechanically for 60min, and then cool down for later use.

[0142] (4) Mix the products obtained from (2) and (3) with 20g of triglycidyl phosphate at 25°C for 3min, and the resulting composition is ready for use.

[0143]

Example 8

[0144] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0145]

[0146] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0147] (1) Heat 50g of bisphenol A epoxy resin and 10g of ethylene glycol diglycidyl ether to 100℃ and keep warm for 15min;

[0148] (2) Add 20g of triglycidyl isocyanurate, stir mechanically for 30 minutes, and then cool down for later use;

[0149] (3) Mix the product obtained in (2), 30g of isophorone diamine and 20g of triglycidyl phosphate at 20°C for 2 min, and the resulting composition is ready for use.

[0150]

Example 9

[0151] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0152]

[0153] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0154] (1) Heat 50g of bisphenol A epoxy resin and 20g of ethylene glycol diglycidyl ether to 100℃ and keep warm for 15min;

[0155] (2) Add 15g of triglycidyl isocyanurate, stir mechanically for 30 minutes, and then cool down for later use;

[0156] (3) Mix the product obtained in (2), 20g of triethylenetetramine and 15g of triglycidyl phosphate at 20°C for 2 min, and the resulting composition is ready for use.

[0157]

Example 10

[0158] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0159]

[0160] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0161] (1) Heat 75g of TDE-85 epoxy resin to 100℃ and keep it warm for 15min;

[0162] (2) Add 5g of triglycidyl isocyanurate, stir mechanically for 30 minutes, and then cool down for later use;

[0163] (3) Heat 120g of methyltetrahydrophthalic anhydride to 100℃, add 3g of ethyltriphenylphosphine bromide, stir mechanically for 60min, and then cool down for later use.

[0164] (4) Mix the products obtained from (2) and (3) with 20g of triglycidyl phosphate at 25°C for 3min, and the resulting composition is ready for use.

[0165]

Example 11

[0166] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0167]

[0168]

[0169] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0170] (1) Heat 75g of bisphenol A epoxy resin to 100℃ and keep it warm for 15min;

[0171] (2) Add 5g of triglycidyl isocyanurate, stir mechanically for 30 minutes, and then cool down for later use;

[0172] (3) Heat 120g of maleic anhydride to 100℃, add 3g of ethyltriphenylphosphine bromide, stir mechanically for 60min, and then cool down for later use.

[0173] (4) Mix the products obtained in (2) and (3) with 20g of triglycidyl phosphate at 55°C for 4min, and the resulting composition is ready for use.

[0174]

Example 12

[0175] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0176]

[0177] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0178] (1) Heat 75g of bisphenol A epoxy resin to 100℃ and keep it warm for 15min;

[0179] (2) Add 5g of triglycidyl isocyanurate, stir mechanically for 30 minutes, and then cool down for later use;

[0180] (3) Heat 120g of methyltetrahydrophthalic anhydride to 100℃, add 3g of imidazole, stir mechanically for 60min, and then cool down for later use.

[0181] (4) Mix the products obtained from (2) and (3) with 20g of triglycidyl phosphate at 25°C for 3min, and the resulting composition is ready for use.

[0182]

Example 13

[0183] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0184]

[0185] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0186] (1) Heat 55g of bisphenol A epoxy resin and 20g of glycerol triglycidyl ether to 100℃ and keep warm for 15min;

[0187] (2) Add 5g of triglycidyl isocyanurate, stir mechanically for 30 minutes, and then cool down for later use;

[0188] (3) Heat 120g of methyltetrahydrophthalic anhydride to 100℃, add 3g of ethyltriphenylphosphine bromide, stir mechanically for 60min, and then cool down for later use.

[0189] (4) Mix the products obtained from (2) and (3) with 20g of triglycidyl phosphate at 25°C for 3min, and the resulting composition is ready for use.

[0190]

Example 14

[0191]

[0192] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0193] (1) Heat 80g of bisphenol A epoxy resin to 100℃ and keep it warm for 15min;

[0194] (2) Add 10g of triglycidyl isocyanurate, stir mechanically for 30 minutes, and then cool for later use;

[0195] (3) Heat 120g of methyltetrahydrophthalic anhydride to 100℃, add 3g of ethyltriphenylphosphine bromide, stir mechanically for 60min, and then cool down for later use.

[0196] (4) Mix the products obtained in (2) and (3) with 10g of triglycidyl phosphate at 25°C for 3min, and the resulting composition is ready for use.

[0197] Comparative Example 1

[0198] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0199] Bisphenol A epoxy resin (CYD128, Baling Petrochemical) 100 parts

[0200] 3 parts of ethyltriphenylphosphine bromide

[0201] 120 parts of methyltetrahydrophthalic anhydride

[0202] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0203] (1) Heat 120g of methyltetrahydrophthalic anhydride to 100℃, add 3g of ethyltriphenylphosphine bromide, stir mechanically for 60min, and then cool down for later use.

[0204] (2) Mix the product obtained in (1) with 100g of bisphenol A epoxy resin at 25°C for 3min, and the resulting composition is ready for use.

[0205] Comparative Example 2

[0206] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0207]

[0208] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0209] (1) Heat 80g of bisphenol A epoxy resin to 100℃ and keep it warm for 15min;

[0210] (2) Add 20g of triglycidyl isocyanurate, stir mechanically for 60min, and then cool for later use;

[0211] (3) Heat 120g of methyltetrahydrophthalic anhydride to 100℃, add 3g of ethyltriphenylphosphine bromide, stir mechanically for 60min, and then cool down for later use.

[0212] (4) Mix the products obtained from (2) and (3) at 25°C for 4 min, and the resulting composition is ready for use.

[0213] Example 13

[0214] Comparative Example 3

[0215] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0216]

[0217] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0218] (1) Heat 120g of methyltetrahydrophthalic anhydride to 100℃, add 3g of ethyltriphenylphosphine bromide, stir mechanically for 60min, and then cool down for later use.

[0219] (2) Mix the product of (1), 80g of bisphenol A epoxy resin and 20g of triglycidyl phosphate at 25°C for 3min, and the resulting composition is ready for use.

[0220] The 20 parts of TGIC added in Comparative Example 2 or the triglycidyl phosphate added in Comparative Example 3 serve as both a flame retardant and a matrix resin. Therefore, in Comparative Examples 2 and 3, the total amount of matrix resin is actually 100 parts.

[0221] Comparative Example 4

[0222] A flame-retardant epoxy resin composition, comprising, by weight parts:

[0223]

[0224] Among them, the N and P elements in melamine phosphate have a synergistic flame-retardant effect.

[0225] The preparation method of the flame-retardant epoxy resin composition is as follows:

[0226] (1) Heat 120g of methyltetrahydrophthalic anhydride to 100℃, add 3g of ethyltriphenylphosphine bromide, stir mechanically for 60min, and then cool down for later use.

[0227] (2) Mix the product of (1), 100g of bisphenol A epoxy resin and 20g of melamine phosphate at 25°C for 3min, and the resulting composition is ready for use.

[0228] The properties of the flame-retardant epoxy resin compositions prepared in the embodiments and comparative examples of the present invention after curing are shown in Table 1.

[0229] Table 1

[0230]

[0231] Comparing the results of Comparative Examples 1 and 4, it can be seen that the flame-retardant epoxy resin prepared with conventional flame retardants has significantly reduced thermal and mechanical properties compared to unmodified epoxy resin. Comparing the results of Comparative Examples 1, 2, and 3 with those of Example 14, it can be seen that the present invention uses specific reactive phosphorus- and nitrogen-containing flame retardants, which not only have flame-retardant effects but also participate in the curing reaction as an epoxy resin matrix. The flame-retardant epoxy resin prepared by the synergistic effect of these two agents, compared to flame-retardant epoxy resin prepared with additive flame retardants, significantly improves the thermal and mechanical properties of the product while ensuring a UL94V0 flame retardant rating.

[0232] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0233] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0234] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0235] In the context of this specification, except where expressly stated otherwise, any matters or issues not mentioned shall apply directly to those known in the art without any modification.

Claims

1. A composition of flame-retardant epoxy resin, comprising, by weight, the following substances: 100 parts by weight of epoxy resin; 10-100 parts by weight of organic flame retardant; Accelerator 0-10 parts by weight; Curing agent 30~260 parts by weight; Epoxy resin diluent 0-50 parts by weight; The epoxy resin is selected from one of glycidyl ether epoxy resin and glycidyl ester epoxy resin; The organic flame retardant is selected from organic nitrogen-containing flame retardants and organic phosphorus-containing flame retardants; The organic nitrogen-containing flame retardant is selected from triglycidyl isocyanurate; The organic phosphorus-containing flame retardant is selected from triglycidyl phosphate; Based on the total weight of epoxy resin and organic flame retardant as 100%, The mass percentage of organic nitrogen-containing flame retardants is 5% to 25%; the mass percentage of organic phosphorus-containing flame retardants is 5% to 25%.

2. The flame-retardant epoxy resin composition according to claim 1, characterized in that: Based on the total weight of epoxy resin and organic flame retardant as 100%, The mass percentage of organic nitrogen-containing flame retardants is 5% to 22.5%; The mass percentage of organic phosphorus-containing flame retardants is 5% to 22.5%.

3. The flame-retardant epoxy resin composition according to claim 2, characterized in that: Based on the total weight of epoxy resin and organic flame retardant as 100%, the mass percentage of organic flame retardant is 25% to 45%.

4. The flame-retardant epoxy resin composition according to claim 1, characterized in that: Accelerator 0-6 parts by weight; and / or, 40-240 parts by weight of curing agent; and / or, 0-40 parts by weight of epoxy resin diluent.

5. The flame-retardant epoxy resin composition according to claim 1, characterized in that: The glycidyl ether epoxy resin is selected from one of bisphenol A epoxy resin, bisphenol F epoxy resin, and phenolic epoxy resin.

6. The flame-retardant epoxy resin composition according to claim 1, characterized in that: The glycidyl ester epoxy resin is selected from one of 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester and 2,3-epoxypropyl methacrylate.

7. The flame-retardant epoxy resin composition according to claim 6, characterized in that: The epoxy value of the epoxy resin is 0.10~1.00 mol / 100g.

8. The flame-retardant epoxy resin composition according to claim 1, characterized in that: The accelerator is selected from at least one of quaternary ammonium salts, quaternary phosphate salts, imidazoles and their derivatives.

9. The flame-retardant epoxy resin composition according to claim 8, characterized in that: The quaternary ammonium salt is selected from at least one of benzyltriethylammonium bromide and tetraethylammonium bromide; and / or, The quaternary phosphorus salt is selected from at least one of methyltriphenylphosphine bromide, ethyltriphenylphosphine bromide, and butyltriphenylphosphine bromide; and / or The imidazole derivative is selected from at least one of dimethylimidazole and diethyltetramethylimidazole.

10. The flame-retardant epoxy resin composition according to claim 1, characterized in that: The curing agent is selected from at least one of acid anhydride curing agents and amine curing agents.

11. The flame-retardant epoxy resin composition according to claim 10, characterized in that: The anhydride curing agent is selected from at least one of methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, and maleic anhydride; and / or, The amine curing agent is selected from at least one of dicyandiamide, isophorone diamine, triethylenetetramine, polyetheramine, and 3,3′-dimethyl-4,4′-diamino-dicyclohexylmethane.

12. The flame-retardant epoxy resin composition according to claim 1, characterized in that: The epoxy resin diluent is selected from at least one of glycidyl ether diluents.

13. The flame-retardant epoxy resin composition according to claim 12, characterized in that: The epoxy resin diluent is selected from at least one of ethylene glycol diglycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, glycerol triglycidyl ether, and pentaerythritol tetraglycidyl ether.

14. A method for preparing a flame-retardant epoxy resin composition according to any one of claims 1-13, comprising the following steps: An epoxy resin, an organic flame retardant, an optional accelerator, a curing agent, and an optional epoxy resin diluent are mixed evenly to obtain a flame-retardant epoxy resin composition.

15. The method for preparing the flame-retardant epoxy resin composition according to claim 14, characterized in that, Includes the following steps: (1) Heat and melt the epoxy resin and optionally the epoxy resin diluent to obtain a melt; (2) Add the organic nitrogen-containing flame retardant to the melt from step (1) and mix evenly to obtain a mixture; (3) Heat the curing agent and optionally add the accelerator, then mix thoroughly; (4) Mix the mixture obtained in step (2) and the substance obtained in step (3) with the organic phosphorus flame retardant to obtain a flame retardant epoxy resin composition.

16. The method for preparing the flame-retardant epoxy resin composition according to claim 15, characterized in that, Step (1), heat to 90-150℃ to melt; and / or, Step (2), the temperature during uniform mixing is 90-150℃; and / or, Step (3), the temperature during uniform mixing is 90-150℃; and / or, Step (4), the temperature during uniform mixing is 20-60℃.

17. The method for preparing the flame-retardant epoxy resin composition according to claim 16, characterized in that, Step (1): Heat to 90-150℃ to melt, and hold at that temperature for 15-30 minutes after melting; and / or, Step (2), mix thoroughly using mechanical stirring; and / or, Step (3), mix thoroughly using mechanical stirring; and / or, Step (4): Mix thoroughly using mechanical stirring.

18. The method for preparing the flame-retardant epoxy resin composition according to claim 16, characterized in that, Step (2), the mixing time is 30~60 min; and / or, Step (3), the mixing time is 30~60 min; and / or, Step (4), the mixing time is 2-5 minutes.

19. A flame-retardant epoxy resin cured product prepared by curing a composition comprising a flame-retardant epoxy resin according to any one of claims 1-13 or a flame-retardant epoxy resin prepared by the method according to any one of claims 14-18.

20. The flame-retardant epoxy resin cured product according to claim 19, characterized in that, The flame retardant rating of the cured flame-retardant epoxy resin is UL94-V0 or higher.

21. A composition of flame-retardant epoxy resin according to any one of claims 1-13, or a composition of flame-retardant epoxy resin prepared by the method according to any one of claims 14-18, or the use of the cured flame-retardant epoxy resin according to any one of claims 19-20 in flame retardancy.

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