A method for preparing a modified cyanate ester resin

Abstract

The application belongs to the technical field of high polymer materials, and particularly relates to a preparation method of modified cyanate ester resin. The modified cyanate ester resin is prepared by using the phosphorus-containing cyanate ester obtained through modification treatment, the functional components such as the silicon-containing phenolic resin, modified montmorillonite and boron-containing carbon nanotube together, effectively increases the tensile strength of the resin, improves the glass transition temperature, and obtains good flame retardant performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high polymer materials, and particularly relates to a preparation method of modified cyanate ester resin. BACKGROUND

[0002] Cyanate ester (CE) resin refers to a thermosetting resin containing two or more cyanate ester functional groups. The monomer of the CE resin is soluble in most common organic solvents when not cured, such as acetone solution, tetrahydrofuran and butanone solution, etc. The cured product of the CE resin has the following characteristics: high crosslinking density and high crystallinity of the monomer; small shrinkage of the cured product, good dimensional stability, high bending strength and tensile strength; small molecular chain dipole moment of the cured product, excellent dielectric performance, and other advantages such as extremely low dielectric constant. The CE resin is widely used in high-frequency printed circuit boards, electronic and electrical industries, and aerospace fields due to its good forming process.

[0003] A Chinese patent (publication number CN114805801B) discloses a cyanate ester resin with low moisture absorption and a preparation method thereof. The dimethyl-p-xylylene cyanate ester resin prepared by the invention introduces a group with smaller polarity and larger volume into the cyanate ester structure, further reducing the polarity and water absorption of the resin. The introduction of an appropriate amount of bisphenol cyanate ester resin and organic silicon modified epoxy resin into the cyanate ester resin matrix is beneficial to adjusting the crosslinking density from the structure, improves the conversion rate of functional groups, effectively reduces the residual polar groups caused by the curing of the resin, and reduces the water absorption of the resin. However, the patent does not solve the problems of the existing cyanate ester resin material, such as small tensile strength, low glass transition temperature, and poor flame retardant performance, which seriously affect its actual use.

[0004] Therefore, how to modify the resin and introduce functional components to effectively increase the tensile strength of the modified cyanate ester resin, improve the glass transition temperature, and obtain good flame retardant performance has become a direction that needs to be overcome. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a preparation method of modified cyanate ester resin, which aims to solve the problems of the existing cyanate ester resin material, such as small tensile strength, low glass transition temperature, and poor flame retardant performance.

[0006] The present application obtains a phosphorus-containing cyanate ester through modification, and uses functional components such as silicon-containing phenolic resin, modified montmorillonite, and boron-containing carbon nanotubes together to prepare a modified cyanate ester resin, which effectively increases the tensile strength of the resin, improves the glass transition temperature, and obtains good flame retardant performance.

[0007] The technical scheme of the present application is as follows:

[0008] The application provides a preparation method of a modified cyanate ester resin, comprising the following steps:

[0009] Step S1: 4-8 parts of (4-hydroxyphenyl) (diphenyl) phosphate are added into 200-240 parts of N,N-dimethylformamide for stirring and uniformity, then 1-3 parts of sodium hydroxide are added, stirring is carried out at 26-30 DEG C for 2-4 h, 2-4 parts of epichlorohydrin are added, heating reaction is carried out at 50-54 DEG C for 6-8 h, cooling is carried out to room temperature, ethyl acetate extraction is carried out, water washing is carried out, drying is carried out, filtering is carried out, distillation is carried out, and an intermediate product is obtained; 8-10 parts of the intermediate product and 90-100 parts of bisphenol A cyanate ester are pre-polymerized at 106-110 DEG C for 10-30 min, then bubble removal is carried out at 120-130 DEG C for 60-80 min, and a phosphorus-containing cyanate ester is obtained.

[0010] Step S2: 80-90 parts of the phosphorus-containing cyanate ester and 10-20 parts of phenolic resin are mixed for heating and melting treatment, then 2-4 parts of a phenolic compound and 0.04-0.06 parts of a catalyst are added at 80-100 DEG C for stirring for 20-30 min, 6-10 parts of montmorillonite and 4-8 parts of carbon nanotubes are added for stirring for 100-120 min, and a modified cyanate ester resin is obtained.

[0011] The phosphorus-containing cyanate ester is modified by using epichlorohydrin to introduce an epoxy group, the high reactivity of the epoxy group can increase the network density of the resin system, strong interface combination is obtained and stress is dispersed, crack propagation is prevented, and the tensile strength of the resin material is improved; meanwhile, the introduced phosphate ester generates metaphosphoric acid with strong dehydrating property, not easy to volatilize and high ignition point under high temperature conditions, the substrate is isolated from air, the oxygen diffusion and the heat transfer speed between the gas phase and the solid phase system are reduced, and combustion is prevented, so that the oxygen index is improved.

[0012] As a preferred technical scheme of the application, the heating and melting treatment conditions comprise that the stirring speed is 1000-1500 r / min, the temperature is 100-120 DEG C, and the time is 10-20 min.

[0013] As a preferred technical scheme of the application, the phenolic compound is selected from a mixture of one or more of nonyl phenol, p-aminophenol and 4-benzyloxyphenol.

[0014] As a preferred technical scheme of the application, the catalyst is acetylacetone iron and dibutyltin dilaurate; and the mass ratio of acetylacetone iron to dibutyltin dilaurate in the catalyst is (1-2):1.

[0015] As a preferred technical scheme of the present application, the phenolic resin is a silicon-containing phenolic resin; and the preparation method of the silicon-containing phenolic resin comprises: adding 200-220 parts of phenol into 240-260 parts of formaldehyde, stirring for 50-60 min, then adding 2-4 parts of tetraethyl orthosilicate and 2-4 parts of sodium carbonate, and reacting at 80-90℃ for 60-90 min; after the reaction is completed, the pH is adjusted to 6.6-6.8, and vacuum dehydration is performed to obtain the silicon-containing phenolic resin.

[0016] The active functional groups in the silicon-containing phenolic resin can react with the cyanate ester resin, thereby enhancing the interfacial interaction between the two phases and improving the overall mechanical properties of the material; meanwhile, the silicon-containing component helps to increase the toughness of the matrix and reduce the possibility of crack propagation, thereby improving the tensile strength of the resin.

[0017] As a preferred technical scheme of the present application, the montmorillonite is a modified montmorillonite; and the preparation method of the modified montmorillonite comprises: adding 40-50 parts of montmorillonite into 100-140 parts of anhydrous ethanol, uniformly dispersing, then adding 20-30 parts of dioctyl dichlorosilane, and stirring for 20-24 h to obtain silanized montmorillonite; uniformly mixing 40-50 parts of the silanized montmorillonite and 100-120 parts of N,N-dimethylformamide, and adding 20-24 parts of 3-hydroxyphthalic anhydride and 2-4 parts of sodium hydride for modification treatment to obtain the modified montmorillonite.

[0018] As a preferred technical scheme of the present application, the modification treatment is performed at a temperature of 20-26℃ for 30-40 h.

[0019] The modified montmorillonite increases the interlayer spacing of the montmorillonite by introducing anhydride molecules, thereby obtaining a sheet structure with a large specific surface area and a high aspect ratio, and the modified montmorillonite can be uniformly distributed in the cyanate ester resin matrix, limiting the movement of polymer chain segments, so that the molecular chains are not easily rearranged during heating, thereby improving the glass transition temperature of the resin material.

[0020] As a preferred technical scheme of the present application, the carbon nanotube is a boron-containing carbon nanotube; and the preparation method of the boron-containing carbon nanotube comprises: adding 4-8 parts of carbon nanotubes into 100-120 parts of isopropyl alcohol, ultrasonically dispersing for 40-60 min, then adding 40-50 parts of boric acid, stirring at 60-70℃ for 4-6 h, and then performing calcination treatment to obtain carbon nanotube A; adding 4-8 parts of the carbon nanotube A into a mixed solution of 20-30 parts of sulfuric acid and 20-30 parts of nitric acid, controlling the temperature to be 80-90℃, the stirring speed to be 60-80 r / min, and the stirring reaction time to be 6-8 h, centrifuging, and drying to obtain the boron-containing carbon nanotube.

[0021] As a preferred technical scheme of the present application, the calcination treatment conditions include: being placed in a nitrogen atmosphere, heated to 1200-1240 DEG C calcination 1-3h, and then cooled to room temperature.

[0022] As a preferred technical scheme of the present application, the length of the carbon nanotube is 1-3 microns.

[0023] The boron atoms introduced by the boron-containing carbon nanotube can introduce more active sites on the surface of the carbon nanotube, and bond with the cyanate ester resin matrix to form a more firm interface combination, limit the movement of polymer segments through strong interface interaction, and improve the glass transition temperature of the resin material.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] (1) The phosphorus-containing cyanate ester of the present application can not only combine with the hydroxyl groups in the silicon-containing phenolic resin, but also react with the hydroxyl groups of the silicon-containing phenolic resin and the carboxyl groups produced on the surface of the boron-containing carbon nanotube after acidification through the epoxy groups introduced by the modification of the epoxy chloropropane, thereby constructing a high-density network interpenetrating structure. The different materials in the network interpenetrating structure penetrate each other and are physically crosslinked, increasing the interaction force between the interfaces, effectively dispersing external stress, preventing crack propagation, and improving the overall tensile strength of the material. At the same time, the network interpenetrating structure can effectively prevent the rearrangement of molecular chains when heated, thereby improving the thermal stability and glass transition temperature of the entire system.

[0026] (2) The phosphorus-containing cyanate ester of the present application can generate metaphosphoric acid with strong dehydrating property, high ignition point and not easy to volatilize under high temperature conditions, reducing the oxygen diffusion and mass and heat transfer speed between the gas and solid phase systems; the silicon element in the silicon-containing phenolic resin can promote the formation of a dense and stable carbon layer on the surface of the resin, effectively preventing the further decomposition of the internal polymer and the release of volatile products; the modified montmorillonite can form an effective barrier in the polymer matrix when subjected to flame, preventing heat transfer, oxygen diffusion, and the migration of flammable gas to the combustion area, thereby inhibiting the chain reaction in the combustion process; the boron-containing carbon nanotube can increase the electronic density on the surface of the carbon nanotube by introducing boron elements, effectively capturing highly reactive free radicals during the combustion process, and slowing down the combustion process; through the synergistic effect of phosphorus-silicon-boron elements, combined with the joint action of modified montmorillonite, the flame retardant performance of the resin is effectively improved.

[0027] (3) The phosphorus-containing cyanate ester of the present application introduces epoxy groups by modifying with epichlorohydrin, and the high reactivity of the epoxy groups can increase the network density of the resin system, obtain strong interface bonding and disperse stress, prevent crack propagation, and thus improve the tensile strength of the resin material; meanwhile, the introduced phosphoric acid ester generates metaphosphoric acid with strong dehydrating property, not easy to volatilize and high ignition point, under high temperature conditions, which burns with the substrate, isolates the substrate from air, reduces the oxygen diffusion and the mass transfer and heat transfer speed between the gas phase and the solid phase system, and prevents combustion, thereby improving the oxygen index.

[0028] (4) The active functional groups in the silicon-containing phenolic resin of the present application can react with the cyanate ester resin, thereby enhancing the interface interaction between the two phases and improving the overall mechanical properties of the material; meanwhile, the silicon-containing component helps to increase the toughness of the matrix, reduce the possibility of crack propagation, and thus improve the tensile strength of the resin.

[0029] (5) The modified montmorillonite of the present application increases the interlayer spacing of the montmorillonite by introducing anhydride molecules, thereby obtaining a sheet structure with a large specific surface area and high aspect ratio, and being able to uniformly distribute in the cyanate ester resin matrix, limiting the movement of polymer chain segments, so that the molecular chains are not easy to rearrange during heating, thereby improving the glass transition temperature of the resin material.

[0030] (6) The boron atoms introduced by the boron-containing carbon nanotubes can introduce more active sites on the surface of the carbon nanotubes, and bond with the cyanate ester resin matrix to form a stronger interface bonding, limit the movement of polymer chain segments through strong interface interaction, and improve the glass transition temperature of the resin material. DETAILED DESCRIPTION

[0031] In order to facilitate the understanding of the present application, the present application lists the following examples. It should be understood by those skilled in the art that the examples are only to help understand the present application, and should not be regarded as a specific limitation on the present application.

[0032] Some components in the examples and comparative examples are as follows:

[0033] Bisphenol A cyanate ester, model C01MO, purchased from Yangzhou Tianqi New Materials Co., Ltd.;

[0034] Phenolic resin, model PF-8010, purchased from Shandong Shengquan New Materials Co., Ltd.;

[0035] Montmorillonite, model WSG-PN06, purchased from Shanghai Wanzhao Fine Chemical Co., Ltd.;

[0036] Carbon nanotube I, model NC7000, length 2 μm, purchased from Nanocyl Company;

[0037] Carbon nanotube II, model MWNT-1020, length 15 μm, purchased from Shenzhen Nanotech Port Co., Ltd.

[0038] Nonylphenol, CAS No. 84852-15-3, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0039] p-Aminophenol, CAS No. 123-30-8, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0040] 4-Benzyloxyphenol, CAS No. 103-16-2, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.

[0041] Iron acetylacetonate, CAS No. 14024-18-1, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0042] Dibutyltin dilaurate, CAS No. 77-58-7, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.

[0043] (4-Hydroxyphenyl)(diphenyl) phosphate, CAS No. 56806-74-7, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.

[0044] N,N-Dimethylformamide, CAS No. 68-12-2, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0045] Sodium hydroxide, CAS No. 1310-73-2, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0046] Epichlorohydrin, CAS No. 106-89-8, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.

[0047] Ethyl acetate, CAS No. 141-78-6, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0048] Phenol, CAS No. 108-95-2, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.

[0049] Formaldehyde, CAS No. 50-00-0, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0050] Tetraethyl orthosilicate, CAS No. 78-10-4, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0051] Sodium carbonate, CAS No. 497-19-8, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0052] Dioctyl dichlorosilane, CAS No. 18416-07-4, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0053] 3-hydroxyphthalic anhydride, CAS No. 37418-88-5, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0054] Sodium hydride, CAS No. 7646-69-7, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0055] Boric acid, CAS No. 10043-35-3, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0056] Isopropyl alcohol, CAS No. 67-63-0, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0057] Nitric acid, CAS No. 7697-37-2, purchased from Sinopharm Chemical Reagent Co., Ltd.

[0058] Example 1

[0059] The present embodiment provides a preparation method of a modified cyanate ester resin, comprising the following steps:

[0060] Preparation of a silicon-containing phenolic resin: 220 parts of phenol are added to 260 parts of formaldehyde and stirred for 60 min, then 4 parts of tetraethyl orthosilicate and 4 parts of sodium carbonate are added, and the reaction is carried out at 90°C for 60 min. After the reaction is completed, the pH is adjusted to 6.8, and vacuum dehydration is performed to obtain a silicon-containing phenolic resin.

[0061] Preparation of modified montmorillonite: 50 parts of montmorillonite are added to 140 parts of anhydrous ethanol and dispersed uniformly, then 30 parts of dioctyl dichlorosilane are added and stirred for 24 h to obtain silanized montmorillonite; 50 parts of the silanized montmorillonite and 120 parts of N,N-dimethylformamide are mixed uniformly, and 24 parts of 3-hydroxyphthalic anhydride and 4 parts of sodium hydride are added for modification treatment (temperature is 26°C, and time is 30 h) to obtain modified montmorillonite.

[0062] Preparation of boron-containing carbon nanotubes: 8 parts of carbon nanotubes are added to 120 parts of isopropyl alcohol and ultrasonically dispersed for 60 min, then 50 parts of boric acid are added, and stirring is carried out at 70°C for 4 h, followed by calcination treatment, heating to 1240°C under a nitrogen atmosphere, and calcining for 1 h, and then cooling to room temperature to obtain carbon nanotubes A; 8 parts of the carbon nanotubes A are added to a mixture of 30 parts of sulfuric acid and 30 parts of nitric acid, the temperature is controlled at 90°C, the stirring speed is 80 r / min, and stirring is carried out for 6 h, followed by centrifugation and drying to obtain boron-containing carbon nanotubes.

[0063] Step S1: 8 parts of (4-hydroxyphenyl) (diphenyl) phosphate was added into 240 parts of N,N-dimethylformamide and stirred uniformly, then 3 parts of sodium hydroxide was added, stirred at 30℃ for 2h, then 4 parts of epichlorohydrin was added, heated and reacted at 54℃ for 6h, cooled to room temperature, extracted with ethyl acetate, washed with water, dried, filtered, and distilled to obtain an intermediate product; 10 parts of the intermediate product and 100 parts of bisphenol A cyanate were pre-polymerized at 10℃ for 10min, then the bubbles were removed at 130℃ for 60min to obtain a phosphorus-containing cyanate;

[0064] Step S2: 90 parts of the phosphorus-containing cyanate and 20 parts of the silicon-containing phenolic resin were mixed and subjected to heating and melting treatment (stirring speed was 1500r / min, temperature was 120℃, and time was 10min), then 4 parts of nonylphenol and 0.06 parts of a catalyst (0.04 parts of acetylacetone iron and 0.02 parts of dibutyltin dilaurate) were added at 100℃ and stirred for 30min, then 10 parts of modified montmorillonite and 8 parts of boron-containing carbon nanotubes were added and stirred for 120min to obtain a modified cyanate resin.

[0065] Example 2

[0066] The embodiment provides a preparation method of a modified cyanate resin, comprising the following steps:

[0067] Preparation of the silicon-containing phenolic resin: 200 parts of phenol was added into 240 parts of formaldehyde and stirred for 50min, then 2 parts of tetraethyl orthosilicate and 2 parts of sodium carbonate were added, and the mixture was reacted at 80℃ for 90min; after the reaction was completed, the pH was adjusted to 6.6, and vacuum dehydration was performed to obtain the silicon-containing phenolic resin.

[0068] Preparation of the modified montmorillonite: 40 parts of montmorillonite was added into 100 parts of anhydrous ethanol and dispersed uniformly, then 20 parts of dioctyl dichlorosilane was added and stirred for 20h to obtain silanized montmorillonite; 40 parts of the silanized montmorillonite and 100 parts of N,N-dimethylformamide were uniformly mixed, 20 parts of 3-hydroxyphthalic anhydride and 2 parts of sodium hydride were added, and the mixture was subjected to modification treatment (temperature was 20℃, and time was 40h) to obtain the modified montmorillonite.

[0069] Preparation of boron-containing carbon nanotubes: 4 parts of carbon nanotubes were added into 100 parts of isopropanol and ultrasonically dispersed for 40 min, then 40 parts of boric acid was added, and stirred at 60℃ for 6h, then calcination treatment was carried out, placed in a nitrogen atmosphere, heated to 1200℃ and calcined for 3h, then cooled to room temperature to obtain carbon nanotubes A; 4 parts of the carbon nanotubes A were added into a mixture of 20 parts of sulfuric acid and 20 parts of nitric acid, the temperature was controlled at 80℃, the stirring speed was 60r / min, and the stirring reaction was carried out for 8h, then centrifuged and dried to obtain boron-containing carbon nanotubes.

[0070] Step S1: 4 parts of (4-hydroxyphenyl) (diphenyl) phosphate were added into 200 parts of N,N-dimethylformamide and stirred uniformly, then 1 part of sodium hydroxide was added, stirred at 26℃ for 4h, then 2 parts of epichlorohydrin was added, heated and reacted at 50℃ for 8h, cooled to room temperature, extracted with ethyl acetate, washed with water, dried, filtered, and distilled to obtain an intermediate product; 8 parts of the intermediate product and 90 parts of bisphenol A cyanate were pre-polymerized at 106℃ for 30min, then bubbles were removed at 120℃ for 80min to obtain a phosphorus-containing cyanate;

[0071] Step S2: 80 parts of the phosphorus-containing cyanate and 10 parts of silicon-containing phenolic resin were mixed and subjected to heating and melting treatment (stirring speed: 1000r / min, temperature: 100℃, time: 20min), then 2 parts of p-aminophenol and 0.04 parts of catalyst (0.02 parts of acetylacetone iron and 0.02 parts of dibutyltin dilaurate) were added at 80℃ and stirred for 20min, then 6 parts of modified montmorillonite and 4 parts of boron-containing carbon nanotubes were added and stirred for 100min to obtain a modified cyanate resin.

[0072] Example 3

[0073] The present embodiment provides a preparation method of a modified cyanate resin, comprising the following steps:

[0074] Preparation of silicon-containing phenolic resin: 210 parts of phenol were added into 250 parts of formaldehyde and stirred for 55min, then 3 parts of tetraethyl orthosilicate and 3 parts of sodium carbonate were added, and reacted at 85℃ for 80min, after the reaction was completed, the pH was adjusted to 6.7, and vacuum dehydration was performed to obtain a silicon-containing phenolic resin.

[0075] Preparation of modified montmorillonite: 45 parts of montmorillonite were added into 120 parts of anhydrous ethanol and dispersed uniformly, then 25 parts of dioctyl dichlorosilane was added and stirred for 22h to obtain silanized montmorillonite; 45 parts of the silanized montmorillonite and 110 parts of N,N-dimethylformamide were mixed uniformly, 22 parts of 3-hydroxyphthalic anhydride and 3 parts of sodium hydride were added for modification treatment (temperature: 24℃, time: 36h) to obtain modified montmorillonite.

[0076] Preparation of boron-containing carbon nanotubes: 6 parts of carbon nanotubes were added into 110 parts of isopropyl alcohol for ultrasonic dispersion for 50 min, then 45 parts of boric acid was added, stirring at 65℃ for 5h, then calcination treatment, placed in a nitrogen atmosphere, heated to 1220℃ calcination for 2h, then cooled to room temperature, to obtain carbon nanotubes A; 6 parts of the carbon nanotubes A was added into a mixture of 25 parts of sulfuric acid and 25 parts of nitric acid, the temperature was controlled at 85℃, the stirring speed was 70r / min, stirring for 7h, centrifugation, drying, to obtain boron-containing carbon nanotubes.

[0077] Step S1: 6 parts of (4-hydroxyphenyl) (diphenyl) phosphate was added into 220 parts of N,N-dimethylformamide for stirring, then 2 parts of sodium hydroxide was added, stirring at 28℃ for 3h, then 3 parts of epichlorohydrin was added, heating reaction at 52℃ for 7h, cooling to room temperature, ethyl acetate extraction, water washing, drying, filtration, distillation, to obtain an intermediate product; 9 parts of the intermediate product and 95 parts of bisphenol A cyanate were pre-polymerized at 108℃ for 20min, then bubble removal at 125℃ for 70min, to obtain phosphorus-containing cyanate ester;

[0078] Step S2: 85 parts of the phosphorus-containing cyanate ester and 15 parts of silicon-containing phenolic resin were mixed for heating melting treatment (stirring speed was 1200r / min, temperature was 110℃, time was 15min), then 3 parts of 4-benzyloxyphenol and 0.05 parts of catalyst (0.03 parts of acetylacetone iron and 0.02 parts of dibutyltin dilaurate) were added at 90℃ for stirring for 25min, then 8 parts of modified montmorillonite and 6 parts of boron-containing carbon nanotubes were added for stirring for 110min, to obtain modified cyanate ester resin.

[0079] Comparative Example 1

[0080] This comparative example provides a preparation method of cyanate ester resin, which is different from Example 1 in that commercially available bisphenol A cyanate (model C01MO) is used instead of phosphorus-containing cyanate ester.

[0081] Comparative Example 2

[0082] This comparative example provides a preparation method of cyanate ester resin, which is different from Example 1 in that commercially available phenolic resin (model PF-8010) is used instead of silicon-containing phenolic resin.

[0083] Comparative Example 3

[0084] This comparative example provides a preparation method of cyanate ester resin, which is different from Example 1 in that commercially available montmorillonite (model WSG-PN06) is used instead of modified montmorillonite.

[0085] Comparative Example 4

[0086] This comparative example provides a preparation method of cyanate ester resin, which is different from Example 1 in that carbon nanotube I is used instead of boron-containing carbon nanotube.

[0087] Comparative Example 5

[0088] This comparative example provides a preparation method of cyanate ester resin, which is different from Example 1 in that carbon nanotube II is used instead of carbon nanotube I to prepare boron-containing carbon nanotube.

[0089] Comparative Example 6

[0090] This comparative example provides a preparation method of cyanate ester resin, which is different from Example 1 in that the amount of iron acetylacetone in the catalyst is changed to 0.05 parts, and the amount of dibutyltin dilaurate is changed to 0.01 parts.

[0091] Comparative Example 7

[0092] This comparative example provides a preparation method of cyanate ester resin, which is different from Example 1 in that the amount of iron acetylacetone in the catalyst is changed to 0.02 parts, and the amount of dibutyltin dilaurate is changed to 0.04 parts.

[0093] The properties of the cyanate ester resin provided by the above examples and comparative examples are tested, and the testing method is as follows:

[0094] (1) Tensile strength test: tested according to the requirements of “GB / T 2567-2021 Resin Casting Properties Test Method”.

[0095] (2) Glass transition temperature test: tested according to the requirements of “GB / T 19466.2-2004 Differential Scanning Calorimetry for Plastics (DSC) Part 2: Determination of Glass Transition Temperature”.

[0096] (3) Oxygen index test: tested according to the requirements of “GB / T 2406.2-2009 Determination of Combustion Behavior of Plastics by Oxygen Index Method Part 2: Room Temperature Test”.

[0097] The performance test data is shown in Table 1.

[0098] Table 1 Performance Test Results

[0099] Tensile strength (MPa) Glass transition temperature (°C) Oxygen index (%) Example 1 98 203 30.1 Example 2 93 201 29.6 Example 3 96 202 29.9 Comparative Example 1 64 185 21.8 Comparative Example 2 71 189 22.6 Comparative Example 3 66 186 22.1 Comparative Example 4 69 188 22.3 Comparative Example 5 77 194 25.8 Comparative Example 6 82 196 26.5 Comparative Example 7 79 195 26.1

[0100] From the above, the modified cyanate ester resin (Examples 1-3) is prepared by using the phosphorus-containing cyanate ester obtained by the modification treatment, together with the silicon-containing phenolic resin, the modified montmorillonite and the boron-containing carbon nanotube, etc. The tensile strength is 93-98 MPa, the glass transition temperature is 201-203 DEG C, and the oxygen index is 29.6-30.1%.

[0101] Compared with Example 1, the tensile strength is reduced, the glass transition temperature is lowered, and the flame retardant performance is deteriorated (Comparative Example 1) by using the commercially available bisphenol A cyanate ester (model C01MO) instead of the phosphorus-containing cyanate ester; compared with Example 1, the tensile strength is reduced, the glass transition temperature is lowered, and the flame retardant performance is deteriorated (Comparative Example 2) by using the commercially available phenolic resin (model PF-8010) instead of the silicon-containing phenolic resin; compared with Example 1, the tensile strength is reduced, the glass transition temperature is lowered, and the flame retardant performance is deteriorated (Comparative Example 3) by using the commercially available montmorillonite (model WSG-PN06) instead of the modified montmorillonite; compared with Example 1, the tensile strength is reduced, the glass transition temperature is lowered, and the flame retardant performance is deteriorated (Comparative Example 4) by using the carbon nanotube I instead of the boron-containing carbon nanotube; compared with Example 1, the tensile strength is reduced, the glass transition temperature is lowered, and the flame retardant performance is deteriorated (Comparative Example 5) by using the carbon nanotube II instead of the carbon nanotube I to prepare the boron-containing carbon nanotube, since the length of the carbon nanotube II is too large and the modification effect is not good; compared with Example 1, the tensile strength is reduced, the glass transition temperature is lowered, and the flame retardant performance is deteriorated (Comparative Example 6) by changing the amount of the acetylacetone iron in the catalyst to 0.05 parts and the amount of the dibutyltin dilaurate to 0.01 parts, since the amount of the acetylacetone iron is too large and the compounding effect is not good; compared with Example 1, the tensile strength is reduced, the glass transition temperature is lowered, and the flame retardant performance is deteriorated (Comparative Example 7) by changing the amount of the acetylacetone iron in the catalyst to 0.02 parts and the amount of the dibutyltin dilaurate to 0.04 parts, since the amount of the acetylacetone iron is too small and the compounding effect is not good.

[0102] In summary, the modified cyanate ester resin is prepared by using the phosphorus-containing cyanate ester obtained by the modification treatment, together with the silicon-containing phenolic resin, the modified montmorillonite and the boron-containing carbon nanotube, etc. The tensile strength of the resin is effectively increased, the glass transition temperature is improved, and the flame retardant performance is good.

Claims

1. A method for preparing a modified cyanate ester resin, characterized by, The method comprises the following steps: Step S1: 4-8 parts of (4-hydroxyphenyl) (diphenyl) phosphate is added into 200-240 parts of N, N-dimethylformamide to be stirred uniformly, then 1-3 parts of sodium hydroxide is added, stirred at 26-30℃ for 2-4h, then 2-4 parts of epichlorohydrin is added, heated to react for 6-8h at 50-54℃, cooled to room temperature, extracted with ethyl acetate, washed with water, dried, filtered, and distilled to obtain an intermediate product; 8-10 parts of the intermediate product and 90-100 parts of bisphenol A cyanate are pre-polymerized at 106-110℃ for 10-30min, then bubbles are removed at 120-130℃ for 60-80min to obtain a phosphorus-containing cyanate; Step S2: 80-90 parts of the phosphorus-containing cyanate and 10-20 parts of a silicon-containing phenolic resin are mixed to be heated and melted, then 2-4 parts of a phenolic compound and 0.04-0.06 parts of a catalyst are added to be stirred at 80-100℃ for 20-30min, then 6-10 parts of modified montmorillonite and 4-8 parts of boron-containing carbon nanotubes are added to be stirred for 100-120min to obtain a modified cyanate resin; The catalyst is acetylacetone iron and dibutyltin dilaurate; the mass ratio of acetylacetone iron to dibutyltin dilaurate in the catalyst is (1-2):1; The preparation method of the silicon-containing phenolic resin comprises the following steps: 200-220 parts of phenol is added into 240-260 parts of formaldehyde to be stirred for 50-60min, then 2-4 parts of tetraethyl orthosilicate and 2-4 parts of sodium carbonate are added to react at 80-90℃ for 60-90min, after the reaction is completed, the pH value is adjusted to 6.6-6.8, and vacuum dehydration is performed to obtain the silicon-containing phenolic resin; The preparation method of the modified montmorillonite comprises the following steps: 40-50 parts of montmorillonite is added into 100-140 parts of anhydrous ethanol to be uniformly dispersed, then 20-30 parts of dioctyl dichlorosilane is added to be stirred for 20-24h to obtain silanized montmorillonite; 40-50 parts of the silanized montmorillonite and 100-120 parts of N, N-dimethylformamide are uniformly mixed, 20-24 parts of 3-hydroxyphthalic anhydride and 2-4 parts of sodium hydride are added to be modified to obtain the modified montmorillonite; The preparation method of the boron-containing carbon nanotube comprises the following steps: 4-8 parts of carbon nanotubes is added into 100-120 parts of isopropyl alcohol to be ultrasonically dispersed for 40-60min, then 40-50 parts of boric acid is added to be stirred at 60-70℃ for 4-6h, and then calcination treatment is performed to obtain carbon nanotube A; 4-8 parts of the carbon nanotube A is added into a mixed solution of 20-30 parts of sulfuric acid and 20-30 parts of nitric acid, the temperature is controlled to be 80-90℃, the stirring speed is 60-80r / min, stirring reaction is performed for 6-8h, centrifugation is performed, and drying is performed to obtain the boron-containing carbon nanotube; The length of the carbon nanotube is 1-3μm.

2. The method for preparing a modified cyanate ester resin according to claim 1, characterized in that, The heating melting treatment is performed under the conditions of a stirring speed of 1000-1500 r / min, a temperature of 100-120 DEG C, and a time of 10-20 min.

3. The method for preparing a modified cyanate ester resin according to claim 1, characterized in that, The phenolic compound is selected from a mixture of one or more of nonyl phenol, p-aminophenol, and 4-benzyloxyphenol.

4. The method for preparing a modified cyanate ester resin according to claim 1, characterized in that, The modification treatment is performed under the conditions of a temperature of 20-26 DEG C and a time of 30-40 h.

5. The method for preparing a modified cyanate ester resin according to claim 1, characterized in that, The calcination treatment is performed under the conditions of being placed in a nitrogen atmosphere, being heated to 1200-1240 DEG C for calcination for 1-3 h, and then being cooled to room temperature.