Bifunctional reactive flame retardant as well as preparation method and application thereof

Abstract

The invention relates to the technical field of epoxy resin flame retardants, in particular to a bifunctional reactive flame retardant as well as a preparation method and application thereof. The preparation method of the bifunctional reactive flame retardant comprises the following steps: in the presence of a catalyst, carrying out substitution reaction on a bisphenol compound and methyl phosphorus dichloride in a solvent, and then carrying out hydrolysis reaction on a reaction product to obtain the flame retardant, and the bisphenol compound is hydroquinone or bisphenol A. The bifunctional reactive flame retardant prepared by the method can overcome the core corrosion effect of epoxy resin, silica powder and aluminum oxide, and the flame-retardant cured epoxy material prepared by the bifunctional reactive flame retardant has excellent flame retardance.

Description

Technical Field

[0001] The invention relates to the technical field of epoxy resin flame retardants, and in particular to a bifunctional reactive flame retardant and a preparation method and application thereof. Background Art

[0002] The new flame retardant intermediate (DOPO) is a reactive phosphorus-based flame retardant that has been industrialized. Its structure contains an active PH bond, which can react with epoxy groups to produce an intrinsic flame retardant epoxy resin with flame retardant properties. It has been widely used in the fields of electronics and electrical appliances. However, DOPO still has some shortcomings: DOPO has only one active functional group in its molecular structure, and its introduction will reduce the crosslinking density of epoxy resin materials, resulting in a glass transition temperature T of epoxy cured products. g At the same time, the content of flame retardant elements in the DOPO structure is low, only 14.3%, and its flame retardant efficiency needs to be improved.

[0003] At present, phosphorus-containing compounds containing bifunctionality can be used as reactive flame retardants for epoxy resins, which participate in the cross-linking reaction of epoxy resins to prepare flame-retardant epoxy resin materials with excellent flame retardant properties and high Tg. The Chinese invention patent with a publication date of April 7, 2023 and a publication number of CN 115925742 A discloses a bifunctional halogen-free flame retardant and its preparation method and application. The flame retardant is an organophosphorus flame retardant, and its chemical name is 4,4'-bis(phenylphosphine oxide) diphenyl ether. The synthesis method of the flame retardant is to react diphenyl ether with phenyl dichlorophosphine under the action of a Lewis acid catalyst to obtain an intermediate, and the intermediate is then hydrolyzed, extracted, and other steps to obtain the target. The flame retardant of the above invention can only achieve flame retardancy of the resin matrix, but in practical applications, due to the "corrosion" effect, when it is used in combination with silicon micropowder or aluminum oxide, the flame retardant properties of the prepared epoxy composite material will drop sharply. Summary of the invention

[0004] The object of the present invention is to provide a bifunctional reactive flame retardant to solve the problem in the prior art that the flame retardant reduces the flame retardancy of the prepared epoxy composite material when it is used in combination with silicon powder or aluminum oxide.

[0005] The present invention also provides a method for preparing a bifunctional reactive flame retardant to solve the problem in the prior art that the flame retardant reduces the flame retardancy of the prepared epoxy composite material when the flame retardant is used in combination with silicon powder or aluminum oxide.

[0006] The present invention also provides an application of a bifunctional reactive flame retardant in the preparation of a flame retardant epoxy cured product, so as to solve the problem in the prior art that the flame retardant reduces the flame retardancy of the prepared flame retardant epoxy cured product when the flame retardant is used in combination with silicon micropowder or aluminum oxide.

[0007] In order to solve the above problems, the present invention proposes a bifunctional reactive flame retardant, and the technical solution adopted is:

[0008] A bifunctional reactive flame retardant, the structural formula of the bifunctional reactive flame retardant is shown in Formula 1:

[0009]

[0010] Among them, R1 is

[0011] R2 is -CH3.

[0012] The beneficial effects of the present invention are as follows: a dual-active functional group is introduced into the structure of the dual-functional reactive flame retardant of the present invention, and due to its unique structure, the core-corrosion effect of epoxy resin, silicon micropowder and aluminum oxide can be overcome, and the flame-retardant epoxy cured product prepared by the dual-active functional group is used in the preparation of a flame-retardant epoxy cured product, and the prepared flame-retardant epoxy cured product has excellent flame-retardant properties; at the same time, the introduction of the dual-active functional group will not lead to a decrease in the cross-linking density of the epoxy resin, and the flame-retardant epoxy cured product prepared by the dual-active functional group can give it excellent flame-retardant properties without affecting the Tg of the epoxy resin material.

[0013] The present invention also proposes a method for preparing a bifunctional reactive flame retardant, and the technical scheme adopted is:

[0014] A method for preparing a bifunctional reactive flame retardant comprises the following steps: in the presence of a catalyst, a bisphenol compound and methyl phosphorus dichloride undergo a substitution reaction in a solvent, and then the reaction product is subjected to a hydrolysis reaction to obtain the flame retardant; the bisphenol compound is hydroquinone or bisphenol A.

[0015] The beneficial effects of the present invention are as follows: first, a substitution reaction occurs between a bisphenol compound and methyl phosphorus dichloride in a solvent, wherein the substitution reaction is to replace two hydrogen atoms in the bisphenol compound with one chlorine atom in methyl phosphorus dichloride; the reaction product obtained by the substitution reaction is subjected to a hydrolysis reaction in water to obtain a bifunctional reactive flame retardant. The bifunctional reactive flame retardant introduces a biactive functional group into the structure of the bifunctional reactive flame retardant, and due to its unique structure, it can overcome the core-corrosion effect of epoxy resin, silicon micropowder and aluminum oxide, and is used in the preparation of flame-retardant epoxy cured products, and the prepared flame-retardant epoxy cured products have excellent flame retardant properties; at the same time, the introduction of the biactive functional group will not lead to a decrease in the crosslinking density of the epoxy resin, and the flame-retardant epoxy cured products prepared by the bifunctional reactive flame retardant can be used without affecting the epoxy resin material T g In the case of flame retardant properties.

[0016] In order to allow the bisphenol compound and methyl phosphorus dichloride to fully undergo a substitution reaction, preferably, the molar ratio of the bisphenol compound to methyl phosphorus dichloride is 1:(2-3).

[0017] In order to allow the bisphenol compound to undergo a substitution reaction with methyl phosphorus dichloride sufficiently, quickly and effectively, preferably, the catalyst is triethylamine; and the molar ratio of triethylamine to methyl phosphorus dichloride is (2-4):(2-3).

[0018] In order to allow the bisphenol compound and methyl phosphorus dichloride to fully dissolve in the solvent and undergo a substitution reaction, preferably, the solvent is one of toluene and dichloromethane; the ratio of the mass of the solvent to the mole of the bisphenol compound is (200-300 g): 0.1 mol.

[0019] In order to complete the substitution reaction between the bisphenol compound and methyl phosphorus dichloride, preferably, the substitution reaction temperature is room temperature to 60° C., and the time is 4 to 6 hours.

[0020] In order to make the hydrolysis reaction fast and complete, preferably, the temperature of the hydrolysis reaction is 40° C. and the time is 1 to 2 hours.

[0021] The present invention also provides an application of a bifunctional reactive flame retardant in the preparation of a flame retardant epoxy cured product.

[0022] The beneficial effect of the present invention is that the present invention uses a bifunctional reactive flame retardant as a flame retardant material in the preparation of a flame retardant epoxy cured product, which can overcome the core corrosion effect of epoxy resin, silicon micropowder and aluminum oxide. The prepared flame retardant epoxy cured product has excellent flame retardant properties, and the flame retardant performance of the prepared flame retardant epoxy cured product UL-94 can reach V0 level.

[0023] In order to prepare a flame retardant epoxy cured product, preferably, the following steps are included: a bifunctional reactive flame retardant, an epoxy resin, a curing agent and an additive are mixed and then subjected to a curing treatment to obtain a flame retardant epoxy cured product; the additive is silicon micropowder or aluminum oxide.

[0024] In order to make the curing process proceed quickly and fully, preferably, the curing process is as follows: curing at 80° C. for 1 hour, curing at 150° C. for 2 hours, and curing at 180° C. for 2 hours. DETAILED DESCRIPTION

[0025] In the prior art, when flame retardants are used in combination with silicon powder or aluminum oxide, the flame retardancy of the prepared epoxy composite material decreases. The present invention proposes a bifunctional reactive flame retardant, and the structural formula of the bifunctional reactive flame retardant is shown in Formula 1:

[0026]

[0027] Among them, R1 is

[0028] R2 is -CH3.

[0029] The technical concept of the present invention is that a unique P-CH3 bond and a POC bond are introduced into the structure of the reactive flame retardant of the present invention. The synergistic effect of the two structural phosphorus can overcome the core-corrosion effect of epoxy resin, silicon micropowder and aluminum oxide. The flame-retardant epoxy cured product prepared by the reactive flame retardant in epoxy resin has excellent flame retardant properties. At the same time, the reactive flame retardant contains two active PH active functional groups, so the introduction of the reactive flame retardant will not lead to a decrease in the cross-linking density of the epoxy resin. The flame-retardant epoxy cured product prepared by the reactive flame retardant can be used without affecting the epoxy resin material T g In the case of flame retardant properties.

[0030] Specifically, the preparation method of the bifunctional reactive flame retardant comprises the following steps:

[0031] At room temperature, in a nitrogen environment, 0.2-0.3 mol of methyl phosphorus dichloride, 20.2-40.4 g (0.2-0.4 mol) of a catalyst and 100-200 g of a solvent are added to a three-necked flask, and then 100 g of a solvent containing 0.1 mol of a bisphenol compound (0.1 mol of hydroquinone is 11 g, and 0.1 mol of bisphenol A is 11.4 g) is slowly dripped to obtain a mixed solution, and then a substitution reaction is carried out at room temperature to 60°C for 4-6 hours; then 200 ml of water is added, and the mixture is stirred at 40°C for 1-2 hours for a hydrolysis reaction, and the liquids are separated, and then the organic phase is washed with water 3 times (50 ml of water each time), and the solvent is removed after separation to obtain a light yellow liquid, which is the final product, a bifunctional reactive flame retardant.

[0032] Preferably, the bisphenol compound is hydroquinone or bisphenol A.

[0033] Specifically, when the bisphenol compound is hydroquinone, the prepared bifunctional reactive flame retardant is FR1, and its synthesis principle is shown in the following formula:

[0034]

[0035] When the bisphenol compound is bisphenol A, the prepared bifunctional reactive flame retardant is FR2, and its synthesis principle is shown in the following formula:

[0036]

[0037] Specifically, the preparation method of the flame retardant epoxy cured product comprises the following steps:

[0038] 100g of epoxy resin is mixed with 5-20g of functional group reactive flame retardant, 22.0g of curing agent and 100-300g of additives and stirred until they are completely dissolved to obtain a mixed liquid, and the mixed liquid is poured into a mold while hot for curing treatment to obtain a flame retardant epoxy cured product.

[0039] Specifically, when the bifunctional reactive flame retardant is FR1, the prepared flame retardant epoxy cured material is a FR1 type flame retardant epoxy cured material; when the bifunctional reactive flame retardant is FR2, the prepared flame retardant epoxy cured material is a FR2 type flame retardant epoxy cured material.

[0040] Preferably, the curing agent is diaminodiphenylmethane (DDM).

[0041] Preferably, the epoxy resin is epoxy resin EP.

[0042] Preferably, the additive is silicon powder or aluminum oxide.

[0043] The implementation process of the present invention is described in detail below in conjunction with specific embodiments.

[0044] In the following examples and comparative examples, the epoxy resin used is EP, brand E51; the particle size of silicon powder and aluminum oxide is 600 mesh, and the structural formula of the flame retardant FR3 used in the comparative example is:

[0045]

[0046] The remaining raw materials are all common commercial products that can be directly purchased or can be prepared according to conventional techniques in the art.

[0047] 1. Embodiment of the preparation method of the bifunctional reactive flame retardant of the present invention

[0048] Example 1

[0049] The preparation method of the bifunctional reactive flame retardant FR1 comprises the following steps:

[0050] At room temperature, under nitrogen environment, 0.2 mol of methylphosphonium dichloride, 0.4 mol of triethylamine and 100 g of toluene solution are added to a three-necked flask, and then 100 g of toluene solution containing 0.1 mol of hydroquinone is slowly dripped to obtain a mixed solution, and then a substitution reaction is carried out at room temperature for 6 hours; then 200 ml of water is added, and the mixture is stirred at 40°C for 2 hours for hydrolysis reaction, and the mixture is separated, and then the organic phase is washed with water 3 times (50 ml of water each time), and the solvent is removed after separation to obtain a light yellow liquid, which is the final product, a bifunctional reactive flame retardant FR1. The nuclear magnetic and mass spectrometry data of the bifunctional reactive flame retardant FR1 are 1H NMR (300 MHz, Chloroform-d) δ8.18 (m, 1H), 7.63 (d, 4H), 7.21 (m, 1H), 0.78 (d, 6H).

[0051] Example 2

[0052] The preparation method of the bifunctional reactive flame retardant FR1 comprises the following steps:

[0053] At room temperature, under a nitrogen environment, 0.3 mol of methyl phosphorus dichloride, 0.2 mol of triethylamine and 200 g of dichloromethane were added to a three-necked flask, and then 100 g of a dichloromethane solution containing 0.1 mol of hydroquinone was slowly dropped to obtain a mixed solution, which was then heated to 40°C for a substitution reaction for 4 hours, and then 200 ml of water was added, and the mixture was stirred at 40°C for 2 hours for a hydrolysis reaction, and the liquids were separated, and the organic phase was then washed with water 3 times (50 ml of water each time). After separation, the solvent was removed to obtain a light yellow liquid, which was the final product, a bifunctional reactive flame retardant FR1. The nuclear magnetic resonance and mass spectrum data of the bifunctional reactive flame retardant FR1 were 1HNMR (300 MHz, Chloroform-d) δ8.18 (m, 1H), 7.63 (d, 4H), 7.21 (m, 1H), 0.78 (d, 6H).

[0054] Example 3

[0055] The preparation method of the bifunctional reactive flame retardant FR1 comprises the following steps:

[0056] At room temperature, under a nitrogen environment, 0.2 mol of methylphosphonium dichloride, 0.3 mol of triethylamine and 100 g of toluene solution were added to a three-necked flask, and then 100 g of toluene solution containing 0.1 mol of hydroquinone was slowly dripped into it to obtain a mixed solution, which was then heated to 60° C. for a substitution reaction for 5 h; then 200 ml of water was added, and the mixture was stirred at 40° C. for 1 h for a hydrolysis reaction, and the liquid was separated, and the organic phase was then washed with water 3 times (50 ml of water each time). After separation, the solvent was removed to obtain a light yellow liquid, which was the final product, a bifunctional reactive flame retardant FR1. The nuclear magnetic resonance and mass spectrometry data of the bifunctional reactive flame retardant FR1 are as follows: 1 H NMR (300MHz, Chloroform-d) δ 8.18 (m, 1H), 7.63 (d, 4H), 7.21 (m, 1H), 0.78 (d, 6H).

[0057] Example 4

[0058] The preparation method of the bifunctional reactive flame retardant FR2 comprises the following steps:

[0059] At room temperature, under a nitrogen environment, 0.2 mol of methylphosphonium dichloride, 0.4 mol of triethylamine and 200 g of toluene solution were added to a three-necked flask, and then 100 g of toluene solution containing 0.1 mol of bisphenol A was slowly dripped into it to obtain a mixed solution, and then a substitution reaction was carried out at room temperature for 6 hours; then 200 ml of water was added, and the mixture was stirred at 40° C. for 2 hours for hydrolysis reaction, and the liquid was separated, and then the organic phase was washed with water 3 times (50 ml of water each time), and the solvent was removed after separation to obtain a light yellow liquid, which was the final product, a bifunctional reactive flame retardant FR2. The nuclear magnetic resonance and mass spectrometry data of the bifunctional reactive flame retardant FR2 are 1 H NMR (300MHz, Chloroform-d) δ 8.28 (m, 1H), 7.50 (d, 4H), 7.21 (d, 4H), 7.18 (m, 1H), 1.72 (s, 6H), 0.75 (d, 6H).

[0060] Example 5

[0061] The preparation method of the bifunctional reactive flame retardant FR2 comprises the following steps:

[0062] At room temperature, under a nitrogen environment, 0.3 mol of methylphosphonium dichloride, 0.3 mol of triethylamine and 100 g of dichloromethane solution were added to a three-necked flask, and then 100 g of dichloromethane solution containing 0.1 mol of bisphenol A was slowly dripped into it to obtain a mixed solution, which was then heated to 40°C for a substitution reaction for 5 hours; then 200 ml of water was added, and the mixture was stirred at 40°C for 1 hour for a hydrolysis reaction, and the liquids were separated, and the organic phase was then washed with water 3 times (50 ml of water each time). After separation, the solvent was removed to obtain a light yellow liquid, which was the final product, a bifunctional reactive flame retardant FR2. The nuclear magnetic resonance and mass spectrometry data of the bifunctional reactive flame retardant FR2 are as follows: 1 H NMR (300MHz, Chloroform-d) δ 8.28 (m, 1H), 7.50 (d, 4H), 7.21 (d, 4H), 7.18 (m, 1H), 1.72 (s, 6H), 0.75 (d, 6H).

[0063] Example 6

[0064] The preparation method of the bifunctional reactive flame retardant FR2 comprises the following steps:

[0065] At room temperature, under a nitrogen environment, 0.2 mol of methylphosphonium dichloride, 0.2 mol of triethylamine and 100 g of toluene solution were added to a three-necked flask, and then 100 g of toluene solution containing 0.1 mol of bisphenol A was slowly dropped to obtain a mixed solution, which was then heated to 60° C. for a substitution reaction for 4 h; 200 ml of water was then added, and the mixture was stirred at 40° C. for 2 h for a hydrolysis reaction, and the liquid was separated, and the organic phase was then washed with water 3 times (50 ml of water each time). After separation, the solvent was removed to obtain a light yellow liquid, which was the final product, a bifunctional reactive flame retardant FR2. The nuclear magnetic resonance and mass spectrometry data of the bifunctional reactive flame retardant FR2 are as follows: 1 H NMR (300MHz, Chloroform-d) δ 8.28 (m, 1H), 7.50 (d, 4H), 7.21 (d, 4H), 7.18 (m, 1H), 1.72 (s, 6H), 0.75 (d, 6H).

[0066] Example 7

[0067] The preparation method of FR1 flame retardant epoxy cured product comprises the following steps:

[0068] 100 g of epoxy resin (EP) was mixed with 5 g of the functional group reactive flame retardant FR1 prepared in Example 1, 300 g of silicon powder and 22.0 g of DDM curing agent, and stirred until they were completely dissolved to obtain a mixed solution. The mixed solution was poured into a mold while hot for curing treatment. The curing treatment process was 80° C. for 1 h, 150° C. for 2 h, and 180° C. for 2 h to obtain a bifunctional reactive flame retardant epoxy cured product.

[0069] Example 8

[0070] The preparation method of FR1 flame retardant epoxy cured product comprises the following steps:

[0071] 100 g of epoxy resin (EP) was mixed with 10 g of the functional group reactive flame retardant FR1 prepared in Example 2, 300 g of aluminum oxide and 22.0 g of DDM curing agent, and stirred until they were completely dissolved to obtain a mixed solution. The mixed solution was poured into a mold while hot for curing treatment. The curing treatment process was 80° C. for 1 h, 150° C. for 2 h, and 180° C. for 2 h to obtain a bifunctional reactive flame retardant epoxy cured product.

[0072] Example 9

[0073] The preparation method of FR1 flame retardant epoxy cured product comprises the following steps:

[0074] 100 g of epoxy resin (EP) was mixed with 15 g of the functional group reactive flame retardant FR1 prepared in Example 3, 100 g of silicon micropowder and 22.0 g of DDM curing agent, and stirred until they were completely dissolved to obtain a mixed solution. The mixed solution was poured into a mold while hot for curing treatment. The curing treatment process was 80° C. for 1 h, 150° C. for 2 h, and 180° C. for 2 h to obtain a bifunctional reactive flame retardant epoxy cured product.

[0075] Example 10

[0076] The preparation method of FR1 flame retardant epoxy cured product comprises the following steps:

[0077] 100 g of epoxy resin (EP) was mixed with 15 g of the functional group reactive flame retardant FR1 prepared in Example 1, 100 g of aluminum oxide and 22.0 g of DDM curing agent, and stirred until they were completely dissolved to obtain a mixed solution. The mixed solution was poured into a mold while hot for curing treatment. The curing treatment process was 80° C. for 1 h, 150° C. for 2 h, and 180° C. for 2 h to obtain a bifunctional reactive flame retardant epoxy cured product.

[0078] Embodiment 11

[0079] The preparation method of FR2 flame retardant epoxy cured product comprises the following steps:

[0080] 100 g of epoxy resin (EP) was mixed with 5 g of the functional group reactive flame retardant FR2 prepared in Example 4, 300 g of silicon micropowder and 22.0 g of DDM curing agent, and stirred until they were completely dissolved to obtain a mixed solution. The mixed solution was poured into a mold while hot for curing treatment. The curing treatment process was 80° C. for 1 h, 150° C. for 2 h, and 180° C. for 2 h to obtain a bifunctional reactive flame retardant epoxy cured product.

[0081] Example 12

[0082] The preparation method of FR2 flame retardant epoxy cured product comprises the following steps:

[0083] 100 g of epoxy resin (EP) was mixed with 10 g of the functional group reactive flame retardant FR2 prepared in Example 5, 200 g of silicon powder and 22.0 g of DDM curing agent, and stirred until they were completely dissolved to obtain a mixed solution. The mixed solution was poured into a mold while hot for curing treatment. The curing treatment process was 80° C. for 1 h, 150° C. for 2 h, and 180° C. for 2 h to obtain a bifunctional reactive flame retardant epoxy cured product.

[0084] Embodiment 13

[0085] The preparation method of FR2 flame retardant epoxy cured product comprises the following steps:

[0086] 100 g of epoxy resin (EP) was mixed with 15 g of the functional group reactive flame retardant FR2 prepared in Example 6, 100 g of aluminum oxide and 22.0 g of DDM curing agent, and stirred until they were completely dissolved to obtain a mixed solution. The mixed solution was poured into a mold while hot for curing treatment. The curing treatment process was 80° C. for 1 h, 150° C. for 2 h, and 180° C. for 2 h to obtain a bifunctional reactive flame retardant epoxy cured product.

[0087] Embodiment 14

[0088] The preparation method of FR2 flame retardant epoxy cured product comprises the following steps:

[0089] 100 g of epoxy resin (EP) was mixed with 20 g of the functional group reactive flame retardant FR2 prepared in Example 4, 300 g of aluminum oxide and 22.0 g of DDM curing agent, and stirred until they were completely dissolved to obtain a mixed solution. The mixed solution was poured into a mold while hot for curing treatment. The curing treatment process was 80° C. for 1 h, 150° C. for 2 h, and 180° C. for 2 h to obtain a bifunctional reactive flame retardant epoxy cured product.

[0090] Two comparison ratios

[0091] Comparative Example 1

[0092] The preparation method of the epoxy cured product of this comparative example is different from that of Example 7 in that the functional group reactive flame retardant FR1 and silicon powder are not added, and the specific steps are as follows:

[0093] 100 g of epoxy resin (EP) was mixed with 22.0 g of DDM curing agent and stirred until they were completely dissolved to obtain a mixed solution. The mixed solution was poured into a mold while hot for curing treatment. The curing treatment process was 80°C for 1 hour, 150°C for 2 hours, and 180°C for 2 hours to obtain an epoxy cured product.

[0094] Comparative Example 2

[0095] The preparation method of the epoxy cured product in this comparative example is different from that in Example 7 in that the added flame retardant is FR3 with a mass of 10 g. The specific steps are as follows:

[0096] 100g of epoxy resin (EP), 10g of flame retardant FR3, 300g of silicon powder and 22.0g of DDM curing agent were mixed and stirred until they were completely dissolved. The mixed liquid was poured into the mold while hot for curing treatment. The curing treatment process was 80°C for 1h, 150°C for 2h, and 180°C for 2h to obtain an epoxy cured product.

[0097] Comparative Example 3

[0098] The preparation method of the epoxy cured product in this comparative example is different from that in Example 8 in that the flame retardant added is FR3, and the specific steps are as follows:

[0099] 100 g of epoxy resin (EP), 10 g of flame retardant FR3, 300 g of aluminum oxide and 22.0 g of DDM curing agent were mixed and stirred until they were completely dissolved. The mixed liquid was poured into a mold while hot for curing. The curing process was 80°C for 1 hour, 150°C for 2 hours, and 180°C for 2 hours to obtain an epoxy cured product.

[0100] Comparative Example 4

[0101] The preparation method of the epoxy cured product in this comparative example is different from that in Example 9 in that the flame retardant added is FR3, and the specific steps are as follows:

[0102] 100 g of epoxy resin (EP), 15 g of flame retardant FR3, 100 g of silicon powder and 22.0 g of DDM curing agent were mixed and stirred until they were completely dissolved. The mixed liquid was poured into the mold while hot for curing treatment. The curing process was 80°C for 1 hour, 150°C for 2 hours, and 180°C for 2 hours to obtain an epoxy cured product.

[0103] Comparative Example 5

[0104] The preparation method of the epoxy cured product of this comparative example is different from that of Example 10 in that the flame retardant added is FR3, and the specific steps are as follows:

[0105] 100 g of epoxy resin was mixed with 15 g of flame retardant FR3, 100 g of aluminum oxide and 22.0 g of DDM curing agent and stirred until they were completely dissolved. The mixture was poured into a mold while hot for curing. The curing process was 80°C for 1 h, 150°C for 2 h, and 180°C for 2 h to obtain an epoxy cured product.

[0106] 3. Experimental Examples

[0107] The flame retardant performance levels of the flame retardant epoxy cured products prepared in Examples 7-14 and the epoxy cured products prepared in Comparative Examples 1-5 were tested in accordance with GB / T 2408-2008. The results are shown in Table 1:

[0108] Table 1 Flame retardant performance grades of flame retardant epoxy cured products prepared in Examples 7-14 and epoxy cured products prepared in Comparative Examples 1-5

[0109]

[0110]

[0111] As can be seen from Table 1, when the functional group reactive flame retardant of the present invention is applied to the flame retardant epoxy cured material containing silicon powder or aluminum oxide, the flame retardant performance UL-94 of the flame retardant epoxy cured material prepared can reach the V0 level. In Comparative Example 1, no flame retardant and additives were used, and the epoxy cured material prepared failed to pass any level of the flame retardant performance UL-94; Comparative Examples 2, 3, 4 and 5 used the flame retardant FR3 in the prior art, and added silicon powder or aluminum oxide at the same time, wherein the epoxy cured materials prepared in Comparative Examples 2 and 3 failed to pass any level of the flame retardant performance UL-94; the flame retardant performance UL-94 of the epoxy cured materials prepared in Comparative Examples 4 and 5 was V2 level. This shows that the functional group reactive flame retardant of the present invention is applied to the flame retardant epoxy cured material containing silicon powder or aluminum oxide, which can significantly improve the flame retardant performance UL-94 of the flame retardant epoxy cured material.

Claims

1. A bifunctional reactive flame retardant, characterized in that: The structural formula of the bifunctional reactive flame retardant is shown in Formula 1: Among them, R1 is R2 is -CH3.

2. The method for preparing a bifunctional reactive flame retardant according to claim 1, characterized in that: The following steps are involved: In the presence of a catalyst, a bisphenol compound and methyl phosphorus dichloride undergo a substitution reaction in a solvent, and then the reaction product undergoes a hydrolysis reaction to obtain the flame retardant; the bisphenol compound is hydroquinone or bisphenol A.

3. The method for preparing a bifunctional reactive flame retardant according to claim 2, characterized in that: The molar ratio of the bisphenol compound to methyl phosphorus dichloride is 1:(2-3).

4. The method for preparing a bifunctional reactive flame retardant according to claim 3, characterized in that: The catalyst is triethylamine; the molar ratio of the triethylamine to methylphosphonium dichloride is (2-4): (2-3).

5. The method for preparing a bifunctional reactive flame retardant according to claim 3, characterized in that: The solvent is one of toluene and dichloromethane; the ratio of the mass of the solvent to the mole of the bisphenol compound is (200-300 g): 0.1 mol.

6. The method for preparing a bifunctional reactive flame retardant according to claim 2, characterized in that: The temperature of the substitution reaction is room temperature to 60° C., and the time is 4 to 6 hours.

7. The method for preparing a bifunctional reactive flame retardant according to claim 2, characterized in that: The temperature of the hydrolysis reaction is 40° C. and the time is 1 to 2 hours.

8. Use of the bifunctional reactive flame retardant according to claim 1 or the bifunctional reactive flame retardant prepared by the preparation method of the bifunctional reactive flame retardant according to any one of claims 2 to 7 in the preparation of flame-retardant epoxy cured products.

9. The use according to claim 8, characterized in that: The method comprises the following steps: mixing a bifunctional reactive flame retardant, an epoxy resin, a curing agent and an additive, and then subjecting the mixture to curing treatment to obtain a flame retardant epoxy cured product; the additive is silicon micropowder or aluminum oxide.

10. The use according to claim 9, characterized in that: The curing process is as follows: curing at 80°C for 1 hour, curing at 150°C for 2 hours, and curing at 180°C for 2 hours.

Images