High-toughness, flame-retardant and smoke-suppressing benzoxazine composition, condensate and preparation method and application thereof

Abstract

The invention discloses a high-toughness, flame-retardant and smoke-suppressing benzoxazine composition, a cured product as well as a preparation method and application of the benzoxazine composition and the cured product. The benzoxazine composition is prepared from daidzein-based benzoxazine resin and benzoxazine resin with a low curing temperature, wherein the daidzein-based benzoxazine resin is prepared from the daidzein-based benzoxazine resin; wherein the curing temperature of the daidzein-based benzoxazine resin is lower than that of the low-curing-temperature benzoxazine resin. According to the invention, a polymerization induced phase separation technology is adopted, two benzoxazine resins with different curing activities and properties are used to obtain the benzoxazine cured product with in-situ toughening effect and flame-retardant and smoke-suppression capabilities, and the benzoxazine cured product is simple to operate, has excellent comprehensive properties and is expected to be applied to the fields of electronic packaging, aerospace, composite materials and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of benzoxazine materials, and in particular relates to a high-toughness flame-retardant and smoke-suppressing benzoxazine composition, a cured product, and a preparation method and application thereof. Background Art

[0002] In recent years, benzoxazine resin has attracted much attention as an emerging high-performance thermosetting resin. Benzoxazine resin has the characteristics of small free volume, strong molecular chain interaction and strong intermolecular stacking, which makes it have good thermodynamic and chemical properties. At the same time, the widespread existence of intermolecular and intramolecular hydrogen bonds hinders the formation of the network, making it have the disadvantages of high brittleness, poor fracture toughness and low crosslinking degree. In addition, the intrinsic flame retardancy and smoke suppression of commercially available benzoxazine resin cured products are usually low, which limits its application in many fields.

[0003] To solve the toughness problem of materials, a commonly used method is to toughen by adding additional toughening agents. For example, a high temperature resistant hot melt benzoxazine resin and a preparation method thereof are disclosed in the patent with publication number CN109354823A, which is used as a toughening agent by adding a second phase such as a rubber elastomer, a thermoplastic resin, and a thermosetting resin. A benzoxazine toughening modification method is disclosed in the patent with publication number CN113583276A, which forms a toughening cross-linked network by modifying polybenzoxazine with a polyhexahydrotriazine structure. However, the introduced second phase component or structure usually has a high flammability, resulting in poor flame retardancy of the modified material. Therefore, how to achieve the simultaneous improvement of toughness and flame retardancy is one of the technical problems that need to be solved in this field. Summary of the invention

[0004] The main purpose of the present invention is to provide a high-toughness flame-retardant and smoke-suppressing benzoxazine composition, a cured product, and a preparation method and application thereof, so as to overcome the shortcomings of the prior art.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes: An embodiment of the present invention provides a high-toughness flame-retardant and smoke-suppressing benzoxazine composition, which includes: a soybean aglycone-based benzoxazine resin and a low-curing temperature benzoxazine resin; wherein the curing temperature of the soybean aglycone-based benzoxazine resin is lower than the curing temperature of the low-curing temperature benzoxazine resin.

[0006] An embodiment of the present invention also provides a high-toughness, flame-retardant and smoke-suppressing benzoxazine cured product, which is formed by curing the aforementioned high-toughness, flame-retardant and smoke-suppressing benzoxazine composition. The benzoxazine cured product has an "island" structure, and the soybean aglycone-based benzoxazine resin is cured to form a continuous phase, and the low-curing temperature benzoxazine resin is cured to form a dispersed phase. At the same time, a copolymer of the soybean aglycone-based benzoxazine resin and the low-curing temperature benzoxazine resin is formed at the interface between the continuous phase and the dispersed phase.

[0007] The embodiment of the present invention also provides a method for preparing the aforementioned high-toughness flame-retardant and smoke-suppressing benzoxazine cured product, which comprises: Providing the aforementioned high-toughness flame-retardant and smoke-suppressing benzoxazine composition; Furthermore, the soybean aglycone-based benzoxazine resin is mixed with a low-curing temperature benzoxazine resin and subjected to a step-by-step temperature-raising curing treatment to obtain a high-toughness flame-retardant and smoke-suppressing benzoxazine cured product.

[0008] The embodiments of the present invention also provide the use of the aforementioned high-toughness, flame-retardant, smoke-suppressing benzoxazine cured product as a high-performance resin matrix or structural material in the fields of electronic packaging, aerospace or composite materials.

[0009] Compared with the prior art, the present invention has the following beneficial effects: (1) The preparation method provided by the present invention is simple and the process control is stable; (2) The high-toughness flame-retardant and smoke-suppressing benzoxazine cured product provided by the present invention has the advantages of being halogen-free, flame-retardant and environmentally friendly; (3) The high-toughness flame-retardant and smoke-suppressant benzoxazine cured product provided by the present invention takes into account both flame-retardant and smoke-suppressant properties and mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0011] Figure 1 is a bar graph of impact strength and limiting oxygen index of the combined cured product and the pure component cured product in Example 1; Figure 2 The nuclear magnetic resonance hydrogen spectrum of the soybean aglycone benzoxazine prepared in Example 1 is 1 H-NMR spectrum. DETAILED DESCRIPTION

[0012] In view of the defects of the prior art, the inventors of this case have proposed the technical solution of the present invention after long-term research and extensive practice. The technical solution mainly utilizes the principle of polymerization-induced phase separation, takes soybean aglycone-based benzoxazine with a low curing temperature as the continuous phase and commercially available benzoxazine with a high curing temperature as the dispersed phase, and forms nanoclusters with toughening and smoke suppression effects by controlling the curing reaction in the blending system. At the same time, soybean aglycone-based benzoxazine itself has good flame retardancy and charring properties, which endows the resulting cured product with excellent toughness and flame retardancy and smoke suppression properties.

[0013] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] Specifically, as one aspect of the technical solution of the present invention, a high-toughness flame-retardant and smoke-suppressing benzoxazine composition comprises: a soybean aglycone-based benzoxazine resin and a low-curing temperature benzoxazine resin; wherein the curing temperature of the soybean aglycone-based benzoxazine resin is lower than the curing temperature of the low-curing temperature benzoxazine resin.

[0015] In some preferred embodiments, the curing temperature of the daidzein-based benzoxazine resin is 150-200°C.

[0016] In some preferred embodiments, the curing temperature of the low curing temperature benzoxazine resin is 200-300°C.

[0017] In some preferred embodiments, the low curing temperature benzoxazine resin is a commercially available benzoxazine resin.

[0018] In some preferred embodiments, the mass ratio of the daidzein-based benzoxazine resin to the low curing temperature benzoxazine resin is 40-80:1-30.

[0019] In some preferred embodiments, the method for preparing the daidzein-based benzoxazine resin comprises: subjecting a mixed reaction system comprising at least an amine compound, an aldehyde compound, daidzein, and a solvent to a Mannich reaction to obtain the daidzein-based benzoxazine resin.

[0020] Furthermore, the structural formula of the amine compound is R 1 -NH 2 ; Among them, R 1 The group is selected from an alkyl group having 1 to 20 carbon atoms, an alkyl substitution, a phenyl group or a phenyl substitution.

[0021] Furthermore, the structural formula of the aldehyde compound is R2 -CHO; among them, R 2 The group is selected from an alkyl group having 1 to 20 carbon atoms, an alkyl substitution, a phenyl group or a phenyl substitution.

[0022] Furthermore, the molar ratio of daidzein, amine compound and aldehyde compound is 1:1:1 to 1:6:6; Further, the solvent includes any one or more combinations of toluene, xylene, 1,4-dioxane, ethanol, tetrahydrofuran, chloroform, dichloromethane, N,N-dimethylformamide, and dimethyl sulfoxide, but is not limited thereto.

[0023] Furthermore, the temperature of the Mannich reaction is 60-150° C., and the time is 6-24 hours.

[0024] Furthermore, the method for preparing the daidzein-based benzoxazine resin further comprises: after the Mannich reaction is completed, adding deionized water to the obtained reaction solution, and then filtering, washing, and drying to obtain the daidzein-based benzoxazine resin.

[0025] In some preferred embodiments, the low curing temperature benzoxazine resin includes any one or more combinations of monofunctional benzoxazine, bisphenol-type benzoxazine, diamine-type benzoxazine, and multifunctional benzoxazine, but is not limited thereto.

[0026] For example, the structural formulas of phenol / aniline benzoxazine, bisphenol A / aniline benzoxazine, and phenol / 4,4'-diaminodiphenylmethane benzoxazine are as follows: .

[0027] Another aspect of an embodiment of the present invention further provides a high-toughness, flame-retardant and smoke-suppressing benzoxazine cured product, which is formed by curing the aforementioned high-toughness, flame-retardant and smoke-suppressing benzoxazine composition. The benzoxazine cured product has an "island" structure, and the soybean aglycone-based benzoxazine resin is cured to form a continuous phase, and the low-curing temperature benzoxazine resin is cured to form a dispersed phase. At the same time, a copolymer of the soybean aglycone-based benzoxazine resin and the low-curing temperature benzoxazine resin is formed at the interface between the continuous phase and the dispersed phase.

[0028] Furthermore, the benzoxazine cured product has structures as shown in formula (I), formula (II) and formula (III): ; Among them, R 3 is selected from an alkyl group having 1 to 20 carbon atoms, an alkyl substituted group, a phenyl group or a phenyl substituted group, R 4 , R 5 The alkyl radicals are independently selected from hydrogen atoms, alkyl radicals having 1 to 20 carbon atoms, alkyl substituents, phenyl radicals or phenyl substituents; m, n and l are independently 1 to 100; X is derived from the main part of the low curing temperature benzoxazine resin, and the structure of formula (III) is a copolymer formed by a soybean aglycone-based benzoxazine resin and a low curing temperature benzoxazine resin.

[0029] In some preferred embodiments, the low curing temperature benzoxazine resin includes any one or more combinations of monofunctional benzoxazine, bisphenol-type benzoxazine, diamine-type benzoxazine, and multifunctional benzoxazine, but is not limited thereto.

[0030] For example, the structural formulas of phenol / aniline benzoxazine, bisphenol A / aniline benzoxazine, and phenol / 4,4'-diaminodiphenylmethane benzoxazine are as follows: .

[0031] In some preferred embodiments, the benzoxazine cured product has an "island-in-sea" structure, wherein the daidzein-based benzoxazine resin is cured to form a continuous phase, and the low-curing temperature benzoxazine resin is cured to form a dispersed phase.

[0032] Another aspect of the embodiments of the present invention further provides a method for preparing the aforementioned high-toughness flame-retardant and smoke-suppressing benzoxazine cured product, which comprises: Providing the aforementioned high-toughness flame-retardant and smoke-suppressing benzoxazine composition; Furthermore, the soybean aglycone-based benzoxazine resin is mixed with a low-curing temperature benzoxazine resin and subjected to a step-by-step temperature-raising curing treatment to obtain a high-toughness flame-retardant and smoke-suppressing benzoxazine cured product.

[0033] In some preferred embodiments, the step-by-step temperature curing process includes: keeping warm at 100-160°C for 1-5h, keeping warm at 160-170°C for 1-5h, keeping warm at 170-180°C for 1-5h, keeping warm at 180-200°C for 1-5h, and keeping warm at 200-220°C for 1-5h.

[0034] The present invention adopts polymerization-induced phase separation technology and obtains a benzoxazine cured product with in-situ toughening effect and flame retardant and smoke suppression capabilities by using two benzoxazine resins with different curing activities and properties. The operation is simple and the comprehensive performance is excellent. It is expected to be applied to electronic packaging, aerospace, composite materials and other fields.

[0035] The present invention is based on polymerization-induced phase separation technology, with a soybean aglycone-based benzoxazine resin with a low curing temperature as a continuous phase and a high curing temperature low curing temperature benzoxazine resin as a dispersed phase. The obtained cured product has high toughness, flame retardancy and smoke suppression properties, and can be used as a high-performance resin matrix or structural material in the fields of electronic packaging, aerospace, composite materials, etc.

[0036] Another aspect of the embodiments of the present invention further provides the use of the aforementioned high-toughness, flame-retardant, and smoke-suppressing benzoxazine cured product as a high-performance resin matrix or structural material in the fields of electronic packaging, aerospace, or composite materials.

[0037] The technical solution of the present invention is further described in detail below in conjunction with several preferred embodiments and drawings. This embodiment is implemented on the premise of the technical solution of the invention, and a detailed implementation method and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0038] The daidzein-based benzoxazine used in the examples and comparative examples of the present invention is homemade, and other raw materials are purchased from the market.

[0039] In the examples and comparative examples, the samples were subjected to a V-notch impact test of the toughness of the samples according to the GB / T 2567-2021 mechanical property test standard and using a Zwick / Roell Z030 instrument. Six groups of tests were performed on each sample, and the average value was taken.

[0040] In the examples and comparative examples, the glass transition temperature of the samples was tested according to ISO 6721-11 glass transition temperature test standard using a dynamic thermal mechanical analyzer (TA DMAQ800).

[0041] Embodiment 1: (1) Synthesis of daidzein-based benzoxazine: Furfurylamine (20 mmol, 1.942 g), paraformaldehyde (40 mmol, 1.2 g) and daidzein (10 mmol, 2.542 g) were mixed in 50 ml of 1,4-dioxane and heated under reflux at 90 °C for 24 hours (magnetic stirring). After the reaction was completed, the mixture was allowed to cool at room temperature and poured into a beaker containing 200 ml of deionized water to obtain a light yellow precipitate. After the product was filtered, it was further washed with deionized water for 3 times and dried at 60 °C to obtain daidzein-based benzoxazine. The H NMR spectrum showed 1 H-NMR images Figure 2 shown.

[0042]

[0043] (2) Preparation of benzoxazine solidified material: Weigh 70 parts of soybean aglycone-based benzoxazine and 30 parts of phenol / 4,4'-diaminodiphenylmethane-based benzoxazine, first dissolve soybean aglycone-based benzoxazine in tetrahydrofuran, evaporate most of the solvent at room temperature, then add phenol / 4,4'-diaminodiphenylmethane-based benzoxazine to the liquid soybean aglycone-based benzoxazine, stir evenly using mechanical stirring and ultrasonic dispersion devices, and obtain a stable soybean aglycone-based benzoxazine and phenol / 4,4'-diaminodiphenylmethane-based benzoxazine mixed system. Inject the mixed solution into the mold for curing, and the curing procedure is: keep warm at 155°C for 2 hours, keep warm at 165°C for 2 hours, keep warm at 175°C for 1 hour, keep warm at 185°C for 1 hour, and keep warm at 205°C for 1 hour.

[0044] The glass transition temperature of the benzoxazine cured product obtained in this example is 331°C and the impact strength is 71.66 kJ / m 2 , limiting oxygen index is 37.8%, UL-94 grade is V-0, total smoke release is 2.1MJ / m 2 ,The test data are summarized in Table 1.

[0045] Figure 1 It is a bar graph of the impact strength and limiting oxygen index of the combined cured product and the pure component cured product in Example 1.

[0046] Embodiment 2: (1) Synthesis of daidzein-based benzoxazine: Same as Example 1.

[0047] (2) Preparation of benzoxazine solidified material: Weigh 80 parts of soybean aglycone-based benzoxazine and 20 parts of phenol / 4,4'-diaminodiphenylmethane-type benzoxazine, first dissolve soybean aglycone-based benzoxazine in tetrahydrofuran, evaporate most of the solvent at room temperature, then add phenol / 4,4'-diaminodiphenylmethane-type benzoxazine to the liquid soybean aglycone-based benzoxazine, stir evenly using mechanical stirring and ultrasonic dispersion devices, and obtain a stable soybean aglycone-based benzoxazine and phenol / 4,4'-diaminodiphenylmethane-type benzoxazine mixed system. Inject the mixed solution into a stainless steel mold for curing, and the curing procedure is: keep warm at 155°C for 2 hours, keep warm at 165°C for 2 hours, keep warm at 175°C for 1 hour, keep warm at 185°C for 1 hour, and keep warm at 205°C for 1 hour.

[0048] The glass transition temperature of the benzoxazine cured product obtained in this example is 333°C and the impact strength is 69.21 kJ / m 2 , limiting oxygen index is 37.6%, UL-94 grade is V-0, total smoke release is 4.3MJ / m 2 ,The test data are summarized in Table 1.

[0049] Embodiment 3: (1) Synthesis of daidzein-based benzoxazine: Same as Example 1.

[0050] (2) Preparation of benzoxazine solidified material: Weigh 40 parts of soybean aglycone-based benzoxazine and 30 parts of phenol / 4,4'-diaminodiphenylmethane-type benzoxazine, first dissolve soybean aglycone-based benzoxazine in tetrahydrofuran, evaporate most of the solvent at room temperature, then add phenol / 4,4'-diaminodiphenylmethane-type benzoxazine to the liquid soybean aglycone-based benzoxazine, stir evenly using mechanical stirring and ultrasonic dispersion devices, and obtain a stable soybean aglycone-based benzoxazine and phenol / 4,4'-diaminodiphenylmethane-type benzoxazine mixed system. Inject the mixed solution into a stainless steel mold for curing, and the curing procedure is: keep warm at 155°C for 2 hours, keep warm at 165°C for 2 hours, keep warm at 175°C for 1 hour, keep warm at 185°C for 1 hour, and keep warm at 205°C for 1 hour.

[0051] The glass transition temperature of the benzoxazine cured product obtained in this example is 313°C and the impact strength is 67.43 kJ / m 2 , limiting oxygen index is 35.6%, UL-94 grade is V-0, total smoke release is 8.2MJ / m 2 ,The test data are summarized in Table 1.

[0052] Embodiment 4: (1) Synthesis of daidzein-based benzoxazine: Same as Example 1.

[0053] (2) Preparation of benzoxazine solidified material: Weigh 70 parts of soybean aglycone-based benzoxazine and 30 parts of phenol / 4,4'-diaminodiphenylmethane-type benzoxazine, first dissolve soybean aglycone-based benzoxazine in tetrahydrofuran, evaporate most of the solvent at room temperature, then add phenol / 4,4'-diaminodiphenylmethane-type benzoxazine to the liquid soybean aglycone-based benzoxazine, stir evenly using mechanical stirring and ultrasonic dispersion devices, and obtain a stable soybean aglycone-based benzoxazine and phenol / 4,4'-diaminodiphenylmethane-type benzoxazine mixed system. Inject the mixed solution into a stainless steel mold for curing, and the curing procedure is: keep warm at 150°C for 2 hours, keep warm at 160°C for 2 hours, keep warm at 170°C for 2 hours, keep warm at 180°C for 2 hours, and keep warm at 200°C for 2 hours.

[0054] The glass transition temperature of the benzoxazine cured product obtained in this example is 334°C and the impact strength is 65.43 kJ / m 2 , limiting oxygen index is 37.4%, UL-94 grade is V-0, total smoke release is 4.6MJ / m 2 ,The test data are summarized in Table 1.

[0055] Embodiment 5: (1) Synthesis of daidzein-based benzoxazine: Same as Example 1.

[0056] (2) Preparation of benzoxazine solidified material: Weigh 70 parts of soybean aglycone-based benzoxazine and 30 parts of bisphenol A / aniline-based benzoxazine, first dissolve soybean aglycone-based benzoxazine in tetrahydrofuran, evaporate most of the solvent at room temperature, then add bisphenol A / aniline-based benzoxazine to the liquid soybean aglycone-based benzoxazine, stir evenly by mechanical stirring and ultrasonic dispersion, and obtain a stable soybean aglycone-based benzoxazine and bisphenol A / aniline-based benzoxazine mixed system. Inject the mixed solution into a stainless steel mold for curing, and the curing procedure is: 155°C / 2 hours, 165°C / 2 hours, 175°C / 1 hour, 185°C / hour, 205°C / 1 hour.

[0057] The glass transition temperature of the benzoxazine cured product obtained in this example is 302°C and the impact strength is 66.72 kJ / m 2 , limiting oxygen index is 36.6%, UL-94 grade is V-0, total smoke release is 6.9MJ / m 2 ,The test data are summarized in Table 1.

[0058] Embodiment 6: (1) Synthesis of daidzein-based benzoxazine: Aniline (20 mmol, 1.862 g), paraformaldehyde (20 mmol, 1.2 g) and daidzein (10 mmol, 2.542 g) were mixed in 50 ml of 1,4-dioxane and heated under reflux at 90°C for 24 hours (magnetic stirring). After the reaction was completed, the mixture was allowed to cool at room temperature and poured into a beaker containing 200 ml of deionized water to obtain a light yellow precipitate. After the product was filtered, it was further washed with deionized water three times and dried at 60°C to obtain daidzein-based benzoxazine.

[0059]

[0060] (2) Preparation of benzoxazine solidified material: Same as Example 1.

[0061] The glass transition temperature of the benzoxazine cured product obtained in this example is 352°C and the impact strength is 68.86 kJ / m 2 , limiting oxygen index is 37.2%, UL-94 grade is V-0, total smoke release is 4.9MJ / m 2 ,The test data are summarized in Table 1.

[0062] Embodiment 7: Synthesis of daidzein-based benzoxazine: Butylamine (20 mmol, 1.462 g), paraformaldehyde (20 mmol, 1.2 g) and daidzein (10 mmol, 2.542 g) were mixed in 50 ml of 1,4-dioxane and heated under reflux at 90 ° C for 24 hours (magnetic stirring). After the reaction was completed, the mixture was left to cool at room temperature and poured into a beaker containing 200 ml of deionized water to obtain a light yellow precipitate. After the product was filtered, it was further washed with deionized water 3 times and dried at 60 ° C to obtain daidzein-based benzoxazine.

[0063]

[0064] (2) Preparation of benzoxazine solidified material: Same as Example 1.

[0065] The glass transition temperature of the benzoxazine cured product obtained in this example is 317°C and the impact strength is 64.43 kJ / m 2 , limiting oxygen index is 35.4%, UL-94 grade is V-1, total smoke release is 9.9MJ / m 2 ,The test data are summarized in Table 1.

[0066] Comparative Example 1: The difference between this comparative example and Example 1 is that there is no need to add commercially available benzoxazine with a high curing temperature, and other operations remain unchanged.

[0067] The glass transition temperature of the benzoxazine cured product obtained in this comparative example is 391°C and the impact strength is 45.71 kJ / m 2 , limiting oxygen index is 30.2%, UL-94 grade is V-1, total smoke release is 12.7MJ / m 2 ,The test data are summarized in Table 1.

[0068] Comparative Example 2: The difference between this comparative example and Example 1 is that 30 parts of phenol / 4,4'-diaminodiphenylmethane type benzoxazine in Example 1 are replaced with an equivalent amount of polyetherimide, and other operations remain unchanged.

[0069] The glass transition temperature of the benzoxazine cured product obtained in this comparative example is 273°C and the impact strength is 53.93 kJ / m 2 , limiting oxygen index is 30.4%, UL-94 grade is V-1, total smoke release is 15.9MJ / m 2 ,The test data are summarized in Table 1.

[0070] Comparative Example 3: The difference between this comparative example and Example 1 is that 30 parts of phenol / 4,4'-diaminodiphenylmethane-type benzoxazine in Example 1 are replaced with an equivalent amount of carbon nanotubes, and other operations remain unchanged.

[0071] The glass transition temperature of the benzoxazine cured product obtained in this comparative example is 383°C and the impact strength is 52.16 kJ / m 2 , limiting oxygen index is 30.6%, UL-94 grade is V-1, total smoke release is 12.1MJ / m 2 ,The test data are summarized in Table 1.

[0072] Comparative Example 4: The difference between this comparative example and Example 1 is that no daidzein-based benzoxazine needs to be added, and other operations remain unchanged.

[0073] The glass transition temperature of the benzoxazine cured product obtained in this comparative example is 225°C and the impact strength is 58.02 kJ / m 2 , limiting oxygen index is 28.2%, UL-94 grade is V-2, total smoke release is 18.6MJ / m 2 ,The test data are summarized in Table 1.

[0074] Comparative Example 5: The difference between this comparative example and Example 1 is that 30 parts of daidzein-based benzoxazine and 30 parts of phenol / 4,4'-diaminodiphenylmethane-type benzoxazine are used, and other operations remain unchanged.

[0075] The glass transition temperature of the benzoxazine cured product obtained in this comparative example is 315°C and the impact strength is 61.76 kJ / m 2 , limiting oxygen index is 32.6%, UL-94 grade is V-2, total smoke release is 17.5MJ / m 2 ,The test data are summarized in Table 1.

[0076] Comparative Example 6: The difference between this comparative example and Example 1 is that 90 parts of daidzein-based benzoxazine and 30 parts of phenol / 4,4'-diaminodiphenylmethane-type benzoxazine are used, and other operations remain unchanged.

[0077] The glass transition temperature of the benzoxazine cured product obtained in this comparative example is 368°C and the impact strength is 62.84 kJ / m 2 , limiting oxygen index is 33.8%, UL-94 grade is V-1, total smoke release is 16.9MJ / m 2 ,The test data are summarized in Table 1.

[0078] Table 1 Properties of the benzoxazine cured products obtained in Examples 1-7 and Comparative Examples 1-6

[0079] Note: 1 ,t 2 They are the first ignition follow-up time and the second ignition follow-up time respectively.

[0080] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments with other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0081] It should be understood that the technical solution of the present invention is not limited to the above-mentioned specific implementation cases. Any technical deformation made according to the technical solution of the present invention without departing from the scope of protection of the purpose of the present invention and the claims shall fall within the protection scope of the present invention.

Claims

1. A high-toughness flame-retardant and smoke-suppressing benzoxazine composition, characterized in that: include: A daidzein-based benzoxazine resin and a low-curing temperature benzoxazine resin; wherein the curing temperature of the daidzein-based benzoxazine resin is lower than the curing temperature of the low-curing temperature benzoxazine resin.

2. The high-toughness flame-retardant and smoke-suppressing benzoxazine composition according to claim 1, characterized in that: The curing temperature of the daidzein-based benzoxazine resin is 150-200° C.; and / or, the curing temperature of the low curing temperature benzoxazine resin is 200-300° C.; And / or, the mass ratio of the daidzein-based benzoxazine resin to the low curing temperature benzoxazine resin is 40-80:1-30.

3. The high-toughness flame-retardant and smoke-suppressing benzoxazine composition according to claim 1, characterized in that: The preparation method of the soybean aglycone-based benzoxazine resin comprises: A mixed reaction system containing at least an amine compound, an aldehyde compound, daidzein and a solvent is subjected to a Mannich reaction to obtain a daidzein-based benzoxazine resin.

4. The high-toughness flame-retardant and smoke-suppressing benzoxazine composition according to claim 3, characterized in that: The structural formula of the amine compound is R1-NH2; wherein R1 is selected from an alkyl group having 1 to 20 carbon atoms, an alkyl substituent, a phenyl group or a phenyl substituent; And / or, the structural formula of the aldehyde compound is R2-CHO; wherein R2 is selected from an alkyl group having 1 to 20 carbon atoms, an alkyl substituent, a phenyl group or a phenyl substituent; And / or, the molar ratio of daidzein, amine compound and aldehyde compound is 1:1:1 to 1:6:6; And / or, the solvent includes any one or more combinations of toluene, xylene, 1,4-dioxane, ethanol, tetrahydrofuran, chloroform, dichloromethane, N,N-dimethylformamide, and dimethyl sulfoxide; And / or, the temperature of the Mannich reaction is 60-150° C., and the time is 6-24 hours.

5. The high-toughness flame-retardant and smoke-suppressing benzoxazine composition according to claim 3, characterized in that: The method for preparing the daidzein-based benzoxazine resin further comprises: after the Mannich reaction is completed, adding deionized water to the obtained reaction solution, and then filtering, washing and drying to obtain the daidzein-based benzoxazine resin.

6. The high-toughness flame-retardant and smoke-suppressing benzoxazine composition according to claim 1, characterized in that: The low curing temperature benzoxazine resin includes any one or more combinations of monofunctional benzoxazine, bisphenol-type benzoxazine, diamine-type benzoxazine, and multifunctional benzoxazine.

7. A high-toughness flame-retardant and smoke-suppressing benzoxazine cured product, characterized in that: The benzoxazine cured product is formed by curing the high-toughness flame-retardant and smoke-suppressing benzoxazine composition according to any one of claims 1 to 6. The benzoxazine cured product has an "island" structure. The soybean aglycone-based benzoxazine resin is cured to form a continuous phase, and the low-curing temperature benzoxazine resin is cured to form a dispersed phase. At the same time, a copolymer of the soybean aglycone-based benzoxazine resin and the low-curing temperature benzoxazine resin is formed at the interface between the continuous phase and the dispersed phase.

8. The method for preparing the high-toughness flame-retardant and smoke-suppressing benzoxazine cured product according to claim 7, characterized in that: include: Provide a high-toughness flame-retardant and smoke-suppressing benzoxazine composition according to any one of claims 1 to 6; Furthermore, the soybean aglycone-based benzoxazine resin is mixed with a low-curing temperature benzoxazine resin and subjected to a step-by-step temperature-raising curing treatment to obtain a high-toughness flame-retardant and smoke-suppressing benzoxazine cured product.

9. The preparation method according to claim 8, characterized in that: The step-by-step temperature rise curing process comprises: keeping warm at 100-160°C for 1-5h, keeping warm at 160-170°C for 1-5h, keeping warm at 170-180°C for 1-5h, keeping warm at 180-200°C for 1-5h, and keeping warm at 200-220°C for 1-5h.

10. Use of the high-toughness, flame-retardant, smoke-suppressing benzoxazine cured product of claim 7 as a high-performance resin matrix or structural material in the fields of electronic packaging, aerospace or composite materials.

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