A toughening agent and a preparation method thereof, and a bismaleimide resin composition

Abstract

The invention discloses a toughening agent and a preparation method thereof, and a bismaleimide resin composition composed of the toughening agent, which is used for toughening and modifying bismaleimide resin, and belongs to the technical field of bismaleimide resin modification. The bismaleimide resin composition includes bismaleimide, a modifier and a toughening agent, and the toughening agent is eugenol allyl polysiloxane. By introducing a plurality of highly reactive allyl groups on polysiloxane, the compatibility of polysiloxane with the bismaleimide / diallyl bisphenol A system is improved, and at the same time, eugenol is used to introduce a benzene ring with better heat resistance on the basis of the original flexible chain of polysiloxane, so that the toughened bismaleimide resin has good heat resistance and excellent bending performance and toughness, and has good application prospects in the fields of high temperature adhesives, aerospace, composite materials, copper clad laminates, electronic packaging materials, etc.

Description

Technical Field

[0001] The invention belongs to the technical field of toughening thermosetting resins, and specifically relates to a toughening agent and a synthesis method thereof, as well as a method and use of the toughening bismaleimide resin to prepare a cured product. Background Art

[0002] Bismaleimide (BMI) resin is a typical thermosetting resin. Its cured resin has a highly cross-linked network, which gives it high heat resistance (glass transition temperature T g >250℃), and excellent mechanical properties, etc., it is widely used as a matrix material in cutting-edge fields such as aerospace, microelectronics, new energy, and national defense. However, like epoxy resin, its cured product has a high or even higher crosslinking density, which makes the material more brittle and less tough. Therefore, while maintaining the inherent characteristics of high temperature resistance, radiation resistance, moisture resistance, corrosion resistance, and low dielectric, the modification research on reducing brittleness and improving toughness has become the key to the preparation of high-performance bismaleimide resin materials.

[0003] Polysiloxane is a polymer whose main chain is composed of silicon oxygen bonds, and has excellent comprehensive properties, such as high thermal stability, excellent flexibility, outstanding flame retardancy and strong hydrophobicity. Obviously, polysiloxane has the potential as a toughening agent for bismaleimide resins, but polysiloxane is usually poorly compatible with the matrix resin, which can cause the defects of the material to increase due to its poor dispersibility. Therefore, to become a good toughening agent, polysiloxane should be functionalized and modified to have a reactivity that can react with the resin matrix. Tsung-Han Ho (Polymer Vol.37No.13, pp.2733-2742, 1996) et al. prepared polysiloxane containing hydrogen at the end group, and improved the compatibility of siloxane and phenolic epoxy resin, so that the resin material has better thermal shock resistance, lower thermal stress and lower hygroscopicity, thereby extending the service life of the device, but the influence of polysiloxane on the toughness of the resin system is not mentioned. Patent CN101062970A introduces polysiloxane containing hydrogen functional groups into the allyl linear phenolic / bismaleimide resin system, and utilizes the silicon hydrogen functional groups to react with allyl groups to improve their compatibility and the performance of the resin. Although the toughness of the resin has been improved to a certain extent, the impact strength is still far below 10kJ / m 2 , which causes the resin material to remain relatively brittle. Summary of the invention

[0004] Based on the above problems, the present invention provides a toughening agent, which functionalizes polysiloxane with biological raw materials eugenol and allyl halogenated hydrocarbons to give it a benzene ring with good thermal stability and an allyl group with excellent reactivity, thereby improving its compatibility and successfully toughening bismaleimide resin. The specific method includes firstly preparing eugenol-based polysiloxane by reacting eugenol and hydrogen-containing polysiloxane, and then preparing eugenol allyl polysiloxane toughening agent by reacting allyl halogenated hydrocarbons and eugenol polysiloxane, which is used to toughen bismaleimide resin; so that bismaleimide resin has both excellent toughness and thermal properties, and can be used as high-temperature adhesive materials, aerospace materials, composite materials, copper-clad laminate materials and electronic packaging materials.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] The first object of the present invention is to provide a toughening agent having a structure shown in the following formula (1):

[0007]

[0008] Wherein, m and n are both integers in the range of 0 to 30.

[0009] The second object of the present invention is to provide a method for preparing the toughening agent, comprising the following steps:

[0010] Step 1, adding octamethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, 1,1,3,3-tetramethyldisiloxane and a cationic polymerization initiator into a container, reacting at 0 to 100° C. for 4 to 48 hours to obtain a hydrogen-containing polysiloxane;

[0011] Step 2, adding the hydrogen-containing polysiloxane prepared in the above step 1, eugenol and a solvent into a container, adding a catalyst or irradiating, reacting at 40 to 200° C. for 4 to 48 hours to obtain eugenol-based polysiloxane;

[0012] Step 3, adding the eugenol-based polysiloxane prepared in the above step 2, allyl halide, acid-binding agent and solvent into a container, reacting at 40-180° C. for 4-48 hours to obtain eugenol allyl polysiloxane, i.e., the toughening agent.

[0013] Furthermore, in step 1, the octamethylcyclotetrasiloxane and 1,3,5,7-tetramethylcyclotetrasiloxane can be prepared in any weight ratio; the content of the 1,1,3,3-tetramethyldisiloxane is 5-20wt% of the total mass of the octamethylcyclotetrasiloxane and the 1,3,5,7-tetramethylcyclotetrasiloxane; the cationic polymerization initiator includes a combination of one or more of proton acids, Lewis acids or other cationic initiators;

[0014] Furthermore, the protonic acid includes but is not limited to concentrated sulfuric acid, phosphoric acid, perchloric acid, chlorosulfonic acid, fluorosulfonic acid, dichloroacetic acid, difluoroacetic acid, trichloroacetic acid, trifluoroacetic acid, and trifluoromethanesulfonic acid; the Lewis acid includes but is not limited to boron trifluoride, aluminum trichloride, titanium tetrachloride, tin tetrachloride, zinc chloride, and antimony pentachloride; the other cationic initiation conditions include but are not limited to iodine, oxonium ions, perchlorates, cycloheptatriene salts, and triphenylmethyl salts.

[0015] Furthermore, in step 2, the hydrogen-containing polysiloxane and eugenol are mixed in a ratio of 1:1 to 10 in terms of the molar ratio of silicon-hydrogen bonds and double bond reaction functional groups; the catalyst includes at least one of organic base compounds, organic peroxides, azo compounds, and precious metal compounds; the radiation conditions include at least one of ultraviolet rays (UV), alpha (α) rays, beta (β) rays, gamma (γ) rays, X-rays, and neutron rays; the solvent includes at least one of N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, ethanol, propanol, acetone, 2-butanone, and dichloromethane.

[0016] Furthermore, in step 3, the eugenol-based polysiloxane and the allyl halide are mixed in a ratio of phenolic hydroxyl group to halogen reaction functional group molar ratio of 1:1 to 10; the acid binding agent includes at least one of triethylamine, pyridine, N,N-diisopropylethylamine, 4-dimethylaminopyridine, triethanolamine, tetrabutylammonium bromide, potassium carbonate, ammonium carbonate, sodium carbonate, sodium hydroxide, calcium hydroxide, potassium hydroxide, ferric hydroxide, calcium carbonate, cesium carbonate, sodium phosphate, and sodium acetate; and the allyl halide includes at least one of allyl iodide, allyl chloride, allyl bromide, and allyl fluoride.

[0017] The third object of the present invention is to provide a bismaleimide resin composition, comprising a bismaleimide resin, a modifier and the above-mentioned toughening agent or a toughening agent prepared by any of the above-mentioned methods.

[0018] Furthermore, the bismaleimide resin contains at least two maleimide groups, including substances with chemical structures shown in the following formulas (2) and (3):

[0019]

[0020] In formula (2), R1 is an organic group having 1 to 30 carbon atoms and containing an aromatic ring structure;

[0021]

[0022] In formula (3), R2 at different positions is independently a hydrogen atom, a hydrocarbon group containing 1 to 4 carbon atoms, or a halogen atom; and n is an integer of 0 to 5.

[0023] Furthermore, the bismaleimide resin, modifier and toughener are mixed at a molar ratio of maleimide group to allyl double bond of 1:0.2 to 1:2, preferably 1:0.8, and the allyl double bond includes the allyl double bond in the modifier and the toughener prepared by the present invention.

[0024] Further, the maleimide resin is 4,4′-methylenebis(N-phenylmaleimide), oligomer of phenylmethanemaleimide, N,N′-m-phenylene bismaleimide, N,N′-m-xylene bismaleimide, N,N′-p-xylene bismaleimide, 2,2′-bis[4-(4-maleimidophenoxy)phenyl]propane, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, N,N-(4-methyl-1,3-phenylene)bismaleimide, 4,4′-diphenyl ether bismaleimide, 4 , 4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, N,N'-p-benzophenone maleimide, N,N'-(methylene-bistetrahydrophenyl) bismaleimide, N,N'-(3,3'-dichloro)-4,4'-diphenylmethane bismaleimide, N,N'-tolidine bismaleimide, N,N'-isophorone bismaleimide, N,N'-p,p'-diphenyldimethylsilyl bismaleimide, N,N'-naphthalene bismaleimide imide, N,N'-4,4'-(1,1'-diphenyl-cyclohexane) bismaleimide, N,N'-3,5-(1,2,4-triazole) bismaleimide, N,N'-pyridine-2,6-diyl bismaleimide, N,N'-maleimide of 4,4'-diamino-triphenyl phosphate, 2,2-bis[3-chloro-4-maleimidophenoxy]phenyl]propane, 2,2-bis[3-methoxy-4-(4-maleimidophenoxy)phenyl]propane, 1,1,1,3,3,3-hexafluoro-2,2-bis[4- The maleimide resin of the present invention is preferably 4,4'-methylenebis(N-phenylmaleimide), oligomers of phenylmethanemaleimide, N,N'-m-phenylene bismaleimide, N,N'-m-xylene bismaleimide, N,N'-p-xylene bismaleimide, 2,2'-bis[4-(4-maleimidophenoxy)phenyl]propane and bis(3-ethyl-5-methyl-4-maleimidophenyl)methane.

[0025] Furthermore, the modifier is a polyallyl modifier.

[0026] Furthermore, the polyallyl modifier is any one of diallyl bisphenol A, diallyl bisphenol F, diallyl bisphenol S, diallyl bisphenol fluorene, diallyl bisphenol ether, diallyl biphenol, and 1,4-di(allylphenol)benzene, or a combination of two or more thereof; the preferred modifier of the present invention is 2,2′-diallyl bisphenol A (DBA).

[0027] The third object of the present invention is to provide a method for preparing the bismaleimide resin composition, comprising the steps of:

[0028] (1) Mix the toughening agent and the modifier, stir for 10 to 30 minutes at 60 to 120° C., and mix evenly to obtain component A;

[0029] (2) mixing component A with bismaleimide resin, stirring at 120 to 180° C. for 10 to 120 minutes, and mixing evenly to obtain a bismaleimide resin composition;

[0030] The fourth object of the present invention is to provide the use of the composition prepared by the above method, wherein the composition is thermally cured into a cured product; the cured product is used as a high-temperature adhesive material, aerospace material, composite material, copper clad laminate material, and electronic packaging material.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The toughening agent prepared by the present invention improves the compatibility of the polysiloxane toughening agent with the bismaleimide resin by introducing multiple highly reactive allyl groups on the polysiloxane. The polysiloxane toughening agent is similarly compatible with the allyl modifier and reacts with the bismaleimide resin at the same time to improve the degree of reaction.

[0033] (2) The toughening agent prepared by the present invention can successfully toughen bismaleimide resin. In the bismaleimide / diallyl bisphenol A system, its impact strength can reach up to 17.9 kJ / m 2 , compared with the pure bismaleimide / diallyl bisphenol A system (13.3 kJ / m 2 ) increased by 34.6%; and its flexural strength is also higher than that of the pure bismaleimide / diallyl bisphenol A system, indicating that the bio-based polysiloxane toughened bismaleimide resin prepared by the present invention has more excellent comprehensive mechanical properties.

[0034] (3) The present invention utilizes the renewable biological raw material eugenol to introduce a benzene ring with heat-resistant properties on the basis of the original flexible chain of polysiloxane, thereby toughening the bismaleimide resin and enhancing its heat resistance. In the bismaleimide / diallyl bisphenol A system, the carbon residue rate at 800°C reaches a maximum of 39%, which is 11% higher than that of the pure bismaleimide / diallyl bisphenol A system (28%).

[0035] (4) The biological raw material eugenol used in the present invention is green, environmentally friendly, safe, non-toxic, widely available, and relatively low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0037] Figure 1 The synthetic route of the toughening agent eugenol allyl polysiloxane in the present invention;

[0038] Figure 2 is the hydrogen nuclear magnetic resonance spectrum of the toughening agent in the present invention;

[0039] Figure 3 is a Fourier transform infrared spectrum of the toughening agent in the present invention;

[0040] Figure 4 A comparison result diagram of the storage modulus-temperature curves of the cured resins provided in Examples 1-4 of the present invention and Comparative Example 1;

[0041] Figure 5 A comparison result diagram of the loss factor-temperature curves of the cured resins provided in Examples 1-4 of the present invention and Comparative Example 1;

[0042] Figure 6 A comparison result diagram of the residual mass-temperature curves of the cured resin provided in Examples 1-4 of the present invention and Comparative Example 1;

[0043] Figure 7 This is a comparison result diagram of the bending strength of the cured resin provided in Examples 1-4 of the present invention and Comparative Example 1;

[0044] Figure 8 This is a comparison chart of the impact strength of the cured resins provided by Examples 1-4 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0045] The present invention will be further described below through preferred embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and provides detailed implementation methods and processes. However, the protection scope of the present invention is not limited to the following embodiments. The experimental methods in the following embodiments without specifying specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturer.

[0046] Example 1

[0047] 1. Preparation of toughening agent: The synthetic route of toughening agent is as follows Figure 1 As shown, it includes the following three steps:

[0048] (1) Preparation of hydrogenated polysiloxane (PMHS): 36 g of octamethylcyclotetrasiloxane, 16 g of hexamethylcyclotetrasiloxane, 5.5 g of tetramethyldisiloxane and 102 μL of trifluoromethanesulfonic acid were added to a flask in sequence and reacted at 25° C. for 24 hours. After the reaction, an excess of anhydrous magnesium sulfate was added, stirred overnight, filtered under reduced pressure, concentrated by rotary evaporation, and dried in vacuum to obtain hydrogenated polysiloxane (PMHS). Figure 2 The integrated areas of b and c show that the number average molecular weight of PMHS is 1540, and m and n are 15 and 5, respectively.

[0049] (2) Preparation of eugenol-based polysiloxane (PMES): 20 g of PMHS, 20 g of eugenol, 20 μL of Karstedt platinum-carbon catalyst and 50 mL of toluene were added to a flask in sequence and reacted at 100° C. for 12 hours. After the reaction, the mixture was concentrated by rotary evaporation, extracted with n-hexane and washed several times, and the lower layer of the product was concentrated by rotary evaporation and vacuum dried to obtain eugenol-based polysiloxane (PMES).

[0050] (3) Preparation of eugenol allyl polysiloxane (PMES-Ally): 20 g of PMES, 18 mL of allyl bromide, 8 g of anhydrous potassium carbonate and 50 mL of dimethylformamide were added to a flask in sequence and reacted at 80°C for 12 hours. After the reaction, the filtrate was filtered and concentrated by rotary evaporation, the crude product was dissolved in dichloromethane, washed with deionized water several times, and the organic layer was concentrated by rotary evaporation and vacuum dried to obtain the target product, eugenol allyl polysiloxane (PMES-Ally).

[0051] According to the attached Figure 1 The reaction formula provided, the Fourier transform infrared spectra and the nuclear magnetic resonance hydrogen spectra of the hydrogen-containing polysiloxane (PMHS), eugenol-based polysiloxane (PMES) and eugenol-allyl polysiloxane (PMES-Ally) prepared in the embodiments of the present invention are respectively shown in the attached Figure 2 and Figure 3 .

[0052] Figure 2These are the hydrogen nuclear magnetic resonance spectra of hydrogen-containing polysiloxane (PMHS), eugenol-based polysiloxane (PMES) and eugenol-allyl polysiloxane (PMES-Ally). The Si-H proton characteristic peak of hydrogenated polysiloxane (PMHS) appears at 4.7ppm, and the characteristic peaks appearing at 0.3-0ppm are all characteristic proton peaks of methyl group; with the completion of the hydrosilylation reaction, the characteristic peak at 4.7ppm on the H NMR spectrum of eugenol-based polysiloxane (PMES) completely disappears, and the characteristic peaks of eugenol (7.0-0.5ppm) appear in turn, especially the characteristic peak of phenolic hydroxyl group appears at 5.5ppm; with the completion of the nucleophilic substitution reaction, the characteristic peak of phenolic hydroxyl group on the H NMR spectrum of eugenol-allyl polysiloxane (PMES-Ally) completely disappears, and the characteristic absorption peaks of allyl group (6.1ppm, 5.4ppm, 5.3ppm and 4.6ppm) appear in turn, and the other peaks are consistent with eugenol-based polysiloxane.

[0053] Figure 3 The infrared spectrum of hydrogenated polysiloxane (PMHS), eugenol-based polysiloxane (PMES) and eugenol-allyl polysiloxane (PMES-Ally) is shown in Figure 1. -1 The characteristic absorption peak of Si-H appeared at 3554cm; while in the infrared spectrum of eugenol-based polysiloxane (PMES), the characteristic absorption peak of Si-H completely disappeared, and the characteristic absorption peak of phenolic hydroxyl group appeared (3554cm -1 ); Similarly, after the nucleophilic substitution reaction, the phenolic hydroxyl group completely disappeared in the infrared spectrum of eugenol allyl polysiloxane (PMES-Ally), indicating that the phenolic hydroxyl group was completely substituted.

[0054] 2. Preparation of bismaleimide resin composition and cured product thereof:

[0055] 28.3 g of diallyl bisphenol A (DBA) and 3.6 g of PMES-Ally were stirred and mixed at 100°C to obtain component A, and then 43 g of BMI was added. The mixture was continuously stirred at 140°C to completely melt the mixture. When the liquid was completely transparent, it was degassed in a vacuum oven at 120°C for 1 hour to obtain a bismaleimide resin composition; then the mixture was poured into a preheated mold, the mold was placed in an oven, and the composition was cured according to a curing procedure of (150°C / 2h)+(180°C / 2h)+(200°C / 2h)+(220°C / 2h)+(240°C / 4h) to obtain the cured resin of Example 1.

[0056] Example 2

[0057] 1. Preparation of toughening agent:

[0058] Same as Example 1.

[0059] 2. Preparation of bismaleimide resin composition and cured product thereof:

[0060] 27.1g of DBA and 7.0g of PMES-Ally were stirred and mixed at 100°C, and then 43g of BMI was added. The mixture was stirred continuously at 140°C to completely melt the mixture. When the liquid was completely transparent, it was degassed in a vacuum oven at 120°C for 1 hour and then poured into a preheated mold. The mold was placed in an oven and the composition was cured according to the curing procedure of (150°C / 2h)+(180°C / 2h)+(200°C / 2h)+(220°C / 2h)+(240°C / 4h) to obtain the cured resin of Example 2.

[0061] Example 3

[0062] 1. Preparation of toughening agent:

[0063] Same as Example 1.

[0064] 2. Preparation of bismaleimide resin cured product:

[0065] 25.9 g of DBA and 10.3 g of PMES-Ally were stirred and mixed at 100°C, and then 43 g of BMI was added. The mixture was stirred continuously at 140°C to completely melt the mixture. When the liquid was completely transparent, it was degassed in a vacuum oven at 120°C for 1 hour and then poured into a preheated mold. The mold was placed in an oven and the composition was cured according to the curing procedure of (150°C / 2h)+(180°C / 2h)+(200°C / 2h)+(220°C / 2h)+(240°C / 4h) to obtain the cured resin of Example 3.

[0066] Example 4

[0067] 1. Preparation of toughening agent:

[0068] Same as Example 1.

[0069] 2. Preparation of bismaleimide resin cured product:

[0070] 24.7g of DBA and 13.5g of PMES-Ally were stirred and mixed at 100°C, and then 43g of BMI was added. The mixture was stirred continuously at 140°C to completely melt the mixture. When the liquid was completely transparent, it was degassed in a vacuum oven at 120°C for 1 hour and then poured into a preheated mold. The mold was placed in an oven and the composition was cured according to the curing procedure of (150°C / 2h)+(180°C / 2h)+(200°C / 2h)+(220°C / 2h)+(240°C / 4h) to obtain the cured resin of Example 4.

[0071] Comparative Example 1

[0072] Preparation of bismaleimide resin cured product:

[0073] 43 g of BMI was added to 29.6 g of DBA, and the mixture was completely melted under continuous stirring at 140° C. When the liquid was completely transparent, it was degassed in a vacuum oven at 120° C. for 1 hour and then poured into a preheated mold. The mold was placed in an oven, and the composition was cured according to the curing procedure of (150° C. / 2 h) + (180° C. / 2 h) + (200° C. / 2 h) + (220° C. / 2 h) + (240° C. / 4 h) to obtain the cured resin of Comparative Example 1.

[0074] As attached Figure 4 As shown, it is a comparison result diagram of the storage modulus-temperature curve of the bismaleimide resin prepared in Example 1, Example 2, Example 3, Example 4 and Comparative Example 1 of the present invention. As can be seen from the figure, compared with the toughened bismaleimide resin prepared in Example 1, Example 2, Example 3 and Example 4, the untoughened bismaleimide resin composition provided in Comparative Example 1 has a higher storage modulus at 50°C. This is because the toughening agent will improve the flexibility of the polymer chain, thereby causing the formed resin cured product to have lower rigidity, among which the storage modulus of Example 3 is the lowest, indicating that the resin cured product of Example 3 has lower rigidity at room temperature.

[0075] As attached Figure 5As shown, it is a comparison result diagram of the loss factor-temperature curve of the bismaleimide resin prepared in Example 1, Example 2, Example 3, Example 4 and Comparative Example 1 of the present invention. It can be seen from the figure that the glass transition temperature of the toughened bismaleimide resin provided in Example 1, Example 2, Example 3 and Example 4 of the present invention is lower than that of the bismaleimide resin provided in Comparative Example 1. The main reason is that the toughening agent improves the flexibility of the chain segments in the cross-linked network, making the migration of the polymer chain segments easier. In the embodiment, the glass transition temperature of the bismaleimide resin provided in Example 3 is 303.6°C, which is higher than the glass transition temperature of the bismaleimide resin provided in other embodiments, indicating that the bismaleimide resin provided in Example 3 has a wider operating temperature range.

[0076] As attached Figure 6 As shown, it is a comparison result diagram of the residual mass-temperature curve of the bismaleimide resin prepared by Example 1, Example 2, Example 3, Example 4 and Comparative Example 1 of the present invention. It can be seen from the figure that the residual carbon rate at 800°C of the toughened bismaleimide resin provided by Example 1, Example 2, Example 3 and Example 4 of the present invention is higher than that of the bismaleimide resin provided by Comparative Example 1, and it shows a trend that the more the content of the toughening agent used, the higher the residual carbon rate. The initial thermal decomposition temperature (the temperature corresponding to the decomposition of 5% of the mass) of the toughened bismaleimide resin provided by Example 1, Example 2, Example 3 and Example 4 of the present invention is equivalent to the bismaleimide resin provided by the comparative example. This is mainly because the structure of the polysiloxane and benzene ring in the toughening agent has good heat resistance and is not easy to decompose at high temperature, so it can improve its residual carbon rate without reducing the initial thermal decomposition temperature.

[0077] As attached Figure 7 As shown, it is a comparison result diagram of the bending strength of the bismaleimide resin prepared in Example 1, Example 2, Example 3, Example 4 and Comparative Example 1 of the present invention. As can be seen from the figure, the bending strength of the toughened bismaleimide resin prepared in Example 1, Example 2, Example 3 and Example 4 of the present invention is higher than that of the bismaleimide resin provided in Comparative Example 1, wherein the bending strength of the bismaleimide resin prepared in Example 3 is as high as 177.1MPa, which is 17.8% higher than the bending strength (150.3MPa) of Comparative Example 1, indicating that the added polysiloxane toughening agent can improve the bending performance of the bismaleimide resin.

[0078] As attached Figure 8As shown, it is a comparison result of the impact strength of the bismaleimide resins prepared in Example 1, Example 2, Example 3, Example 4 and Comparative Example 1 of the present invention. As can be seen from the figure, the impact strength of the toughened bismaleimide resins prepared in Example 1, Example 2, Example 3 and Example 4 of the present invention is higher than that of the bismaleimide resin provided in Comparative Example 1, among which the impact strength of the cured product of the bismaleimide resin composition prepared in Example 3 is as high as 17.9 kJ / m 2 , compared with the impact strength of Comparative Example 1 (13.3 kJ / m 2 ) increased by 34.6%, indicating that the added polysiloxane toughening agent can improve the toughness of bismaleimide resin.

[0079] Based on the above properties, it can be seen that the bismaleimide resin toughened with the eugenol allyl polysiloxane provided in the embodiment has excellent high temperature resistance, high bending performance and toughness compared with the untoughened bismaleimide resin, among which Example 3 has excellent comprehensive performance.

[0080] Table 1 Performance characterization data list of bismaleimide resin in Examples and Comparative Examples

[0081]

Claims

1. A toughening agent, characterized in that: It has the structure shown in the following formula (1): Herein, m is an integer in the range of 15 to 30, and n is an integer in the range of 5 to 30.

2. A method for preparing the toughening agent according to claim 1, characterized in that: The following steps are involved: Step 1, adding octamethylcyclotetrasiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, 1,1,3,3-tetramethyldisiloxane and a cationic polymerization initiator into a container, reacting at 0 to 100° C. for 4 to 48 hours to obtain a hydrogen-containing polysiloxane; Step 2, adding the hydrogen-containing polysiloxane prepared in the above step 1, eugenol and a solvent into a container, adding a catalyst or irradiating, reacting at 40 to 200° C. for 4 to 48 hours to obtain eugenol-based polysiloxane; Step 3, adding the eugenol-based polysiloxane prepared in the above step 2, allyl halogenated hydrocarbon, acid-binding agent and solvent into a container, reacting at 40-180° C. for 4-48 hours to obtain eugenol-based allyl polysiloxane, i.e., the toughening agent.

3. The method for preparing a toughening agent according to claim 2, characterized in that: In step 1, the octamethylcyclotetrasiloxane and the 1,3,5,7-tetramethylcyclotetrasiloxane can be prepared in any weight ratio; the content of the 1,1,3,3-tetramethyldisiloxane is 5-20wt% of the total mass of the octamethylcyclotetrasiloxane and the 1,3,5,7-tetramethylcyclotetrasiloxane; the cationic polymerization initiator includes at least one of proton acids, Lewis acids or other cationic initiators; the other cationic initiators include iodine, oxonium ions, perchlorates, cycloheptatriene salts, and triphenylmethyl salts.

4. The method for preparing a toughening agent according to claim 2, characterized in that: In step 2, the hydrogen-containing polysiloxane and eugenol are mixed in a molar ratio of 1:1 to 10 between silicon-hydrogen bonds and double bond reaction functional groups; the catalyst includes at least one of organic base compounds, organic peroxides, azo compounds, and precious metal compounds; and the radiation conditions include at least one of UV (ultraviolet rays), alpha (α) rays, beta (β) rays, gamma (γ) rays, X-rays, and neutron rays.

5. The method for preparing a toughening agent according to claim 2, characterized in that: In step 3, the eugenol-based polysiloxane and the allyl halide are mixed in a molar ratio of phenolic hydroxyl group to halogen reactive functional group of 1:1-10.

6. A bismaleimide resin composition, characterized in that The invention comprises a bismaleimide resin, a modifier and the toughening agent according to claim 1 or a toughening agent prepared by the method according to any one of claims 2 to 5.

7. The bismaleimide resin composition according to claim 6, characterized in that: The bismaleimide resin contains at least two maleimide groups, and the bismaleimide resin includes at least one of the chemical structures shown in the following formula (2) and formula (3): In formula (2), R1 is an organic group having 1 to 30 carbon atoms and containing an aromatic ring structure; In formula (3), R2 at different positions is independently a hydrogen atom, a hydrocarbon group containing 1 to 4 carbon atoms, or a halogen atom; and n is an integer of 0 to 5.

8. The bismaleimide resin composition according to claim 6, characterized in that: The modifier is a polyallyl modifier, and the bismaleimide resin, the modifier and the toughening agent are mixed in a ratio of 1:0.2 to 1:2 in terms of the molar ratio of maleimide group to allyl double bond.

9. A method for preparing a bismaleimide resin composition according to any one of claims 6 to 8, characterized in that: The steps include: (1) Mix the toughening agent and the modifier, stir for 10 to 30 minutes at 60 to 120° C., and mix evenly to obtain component A; (2) Component A is mixed with bismaleimide resin, and stirred at 120 to 180° C. for 10 to 120 minutes to obtain a bismaleimide resin composition.

10. Use of the composition according to any one of claims 6 to 8 or the composition obtained by the preparation method according to claim 9, characterized in that: The composition is thermally cured to form a cured product; the cured product is used as a high-temperature adhesive material, an aerospace material, a composite material, a copper-clad laminate material, and an electronic packaging material.

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