Polyfunctional benzoxazines containing a biphenyl structure and a method for preparing the same

Abstract

The application belongs to the technical field of thermosetting materials, and provides a multifunctional benzoxazine containing a biphenyl structure and a preparation method thereof. The preparation method takes biphenyl polyamine, monoamine compounds and bifunctional phenolic compounds as raw materials, and a series of multifunctional benzoxazines with a biphenyl structure as a main chain are synthesized through a solvent method. The preparation method has mild reaction conditions, and the prepared product has a low dielectric constant and very excellent thermal stability.

Description

Technical Field

[0001] This invention belongs to the field of thermosetting materials technology, specifically relating to a multifunctional benzoxazine containing a biphenyl structure and its preparation method. Background Technology

[0002] With the widespread adoption of fifth-generation (5G) mobile communication technology, the accelerated development of future sixth-generation (6G) communication technology, and the leapfrog development in cutting-edge fields such as high-performance computing (HPC), artificial intelligence chips, and advanced packaging processes, the electronics and information industry is rapidly advancing towards high-frequency, high-speed transmission, high-power-density integration, miniaturized packaging, and high-reliability service. This series of industrial transformations has placed unprecedentedly stringent standards and extreme requirements on the comprehensive performance of packaging substrates, interconnect substrates, and key packaging materials—the core carriers of chips and circuits. Key indicators such as the dielectric properties, thermal stability, moisture resistance, and mechanical strength of materials directly determine the signal transmission quality, operating efficiency, and lifespan of high-end electronic devices.

[0003] In traditional packaging and circuit substrates, epoxy resin has long held a dominant position due to its advantages such as low cost, mature technology, and good adhesion. However, it has inherent performance limitations that are difficult to overcome: In terms of dielectric properties, the dielectric constant (Dk) of conventional epoxy resins is generally 3.8-4.2, and the dielectric loss factor (Df) is concentrated in the range of 0.018-0.025, which can easily cause signal attenuation, delay, and interference during high-frequency signal transmission. In terms of heat resistance, its glass transition temperature (Tg) is usually only 150-180℃, which can easily lead to softening, deformation, and mechanical property degradation in the high-temperature environment generated by high-power density devices. At the same time, traditional epoxy resins also have the shortcoming of high hygroscopicity. In harsh service environments such as humid and high-temperature environments, moisture absorption can easily lead to substrate warping, interface failure, and decreased insulation performance, seriously affecting the long-term reliability of devices. These core defects make traditional epoxy resins completely unsuitable for the core requirements of high-end application scenarios such as 5G / 6G communication, high-frequency and high-speed circuits, and high-power chip packaging.

[0004] Benzoxazine resins, as a new type of thermosetting phenolic resin with novel structure and excellent performance, have received widespread attention and in-depth research from the global materials science and industry communities since their successful development in the 1990s, thanks to their unique molecular structure and curing characteristics.

[0005] The precursor monomer of polybenzoxazine resin, benzoxazine, has a simple and controllable synthesis process. It is typically prepared in one step via the classic Mannich condensation reaction using readily available primary amine compounds, phenol, and formaldehyde as raw materials. The raw materials are widely available, the synthesis conditions are mild, and it has the potential for large-scale industrial production. The most prominent advantage of this resin lies in its unique curing mechanism: it does not require the addition of strong acid or strong base catalysts; ring-opening polymerization occurs simply through heating. No small molecule byproducts are released during curing, fundamentally overcoming the inherent defects of traditional phenolic resins, such as the release of formaldehyde and water during curing, which leads to porosity and deformation of the substrate. Simultaneously, the cured polybenzoxazine exhibits many superior properties: near-zero volume shrinkage effectively ensures the dimensional accuracy of the encapsulation substrate; extremely high char residue provides excellent thermal stability and flame retardancy; it also possesses good mechanical properties, low dielectric loss characteristics, and chemical corrosion resistance, making it an ideal candidate resin to replace traditional epoxy resins and meet the needs of high-end electronic materials.

[0006] However, it is worth noting that pure benzoxazine resin itself still has obvious performance shortcomings, which limit its direct application in high-end fields, especially in extreme scenarios of ultra-high temperature and long-term high-heat service. Although the heat resistance of benzoxazine is better than that of traditional epoxy resin, its thermal stability and high-temperature mechanical retention rate still need to be further improved, and it cannot fully meet the extreme requirements of ultra-high temperature reliability of the new generation of high-power chips and high-frequency communication devices. Summary of the Invention

[0007] To address the aforementioned shortcomings of existing technologies, this invention provides a polyfunctional benzoxazine containing a biphenyl structure and its preparation method. Using biphenyl polyamines, monoamine compounds, and difunctional phenolic compounds as raw materials, this invention synthesizes a series of polyfunctional benzoxazines with a biphenyl structure as the main chain via a solvent method. This preparation method employs mild reaction conditions, and the resulting products exhibit both low dielectric constants and excellent thermal stability.

[0008] To achieve the above objectives, the solution adopted by the present invention is as follows: A multifunctional benzoxazine containing a biphenyl structure, the multifunctional benzoxazine containing a biphenyl structure having the structure of formula A: Formula A Where n≥1, m≥1; R1 is selected from one of the following: -O-, -S-, -S(=O)-, -S(=O)2-, -C(=O-, or a hydrocarbon group with a substituent; R2 and R3 are each independently selected from one of hydrogen atoms, halogen atoms, alkyl groups having 1-8 carbon atoms, or aryl groups; R4 is selected from one of the following: alkyl, cycloalkyl, allyl, aryl and their derivatives, and furan, which have 1-10 carbon atoms.

[0009] A method for preparing the above-mentioned multifunctional benzoxazine containing a biphenyl structure includes: obtaining it by solvent polymerization of a biphenyl polyamine compound, an amine compound, a phenolic compound and an aldehyde compound; The benzidine polyamine compound has the structure of formula B: Formula B Where n≥1; Amine compounds include monofunctional amine compounds; Phenolic compounds include bifunctional phenolic compounds; Aldehydes include formaldehyde and / or paraformaldehyde, or one of the following: an aqueous solution of formaldehyde.

[0010] Furthermore, in a preferred embodiment of the present invention, the amine compound has the structure of formula C: Formula C R4 is selected from one of the following: alkyl, cycloalkyl, allyl, alkynyl, aryl and their derivatives, and furan, which have 1-10 carbon atoms.

[0011] Furthermore, in a preferred embodiment of the present invention, the phenolic compound has the structure of formula D: Formula D R1 is selected from one of the following: -O-, -S-, -S(=O)-, -S(=O)2-, -C(=O)-, and a hydrocarbon group with a substituent; R2 and R3 are each independently selected from one of hydrogen atoms, halogen atoms, alkyl groups having 1-8 carbon atoms, or aryl groups.

[0012] Further, in a preferred embodiment of the present invention, the method includes the following steps: adding phenolic compounds, aldehyde compounds and organic solvents into a round-bottom flask, heating to 75-80°C, then adding biphenyl polyamine compounds in five equal portions, and finally adding amine compounds, maintaining the temperature at 80-100°C for 120-360 minutes to obtain a mixed solution, filtering to remove the solvent from the filtrate, and drying the solid under vacuum to obtain the final product.

[0013] Furthermore, in a preferred embodiment of the present invention, the molar ratio of the amino functional group of the benzidine polyamine compound to the phenolic hydroxyl functional group of the phenolic compound is 1:1.1-10.

[0014] Furthermore, in a preferred embodiment of the present invention, the molar ratio of the amino functional groups of the biphenyl polyamine compound and the amine compound to the aldehyde compound is 1:2-2.5.

[0015] Furthermore, in a preferred embodiment of the present invention, the molar ratio of the amino functional groups of the biphenyl polyamine compound to the amino functional groups of the amine compound is 1:0.1-9.

[0016] Furthermore, in a preferred embodiment of the present invention, the organic solvent is selected from at least one of toluene, tetrahydrofuran, xylene, N,N-dimethylformamide, and 1,4-dioxane.

[0017] Furthermore, in a preferred embodiment of the present invention, the total addition time of the biphenyl polyamine compound and the amine compound is 40-60 min.

[0018] Furthermore, in a preferred embodiment of the present invention, when the amine compound itself is a liquid, it is added dropwise directly; when the amine compound is a solid, it is first dissolved into an amine compound solution before being added dropwise.

[0019] Furthermore, in a preferred embodiment of the present invention, the conditions for solid vacuum drying are: temperature 60°C and time 12h.

[0020] The beneficial effects of the multifunctional benzoxazine containing a biphenyl structure and its preparation method provided by this invention are: (1) The multifunctional benzoxazine provided by the present invention is obtained by solvent polymerization of biphenyl polyamine compounds, amine compounds, phenolic compounds and aldehyde compounds to obtain a novel chemical structure of multifunctional benzoxazine resin material containing biphenyl structure; (2) The inventors found that introducing a biphenyl skeleton into the multifunctional benzoxazine resin material can further improve its performance. Compared with the single benzene ring structure, the extended biphenyl skeleton can make its electron cloud distribution more uniform and reduce the molecular dipole moment. At the same time, the rigid and non-completely coplanar biphenyl units (with torsion angle between benzene rings) can effectively hinder the close stacking of molecular chains during the polymer network curing process. This can not only significantly improve the glass transition temperature and thermal decomposition stability of the material, but also, due to its highly aromatic intrinsic properties, simultaneously endow the material with extremely low dielectric constant and loss, extremely low water absorption, extremely low coefficient of thermal expansion (CTE) and excellent intrinsic flame retardant properties. The char rate is 45-60% in an inert gas atmosphere at 800℃, which perfectly meets the urgent needs of the new generation of high-frequency and high-speed communication equipment for low-loss substrate materials and aerospace vehicles for high-temperature resistant and ablation-resistant composite materials. (3) The preparation method of the multifunctional benzoxazine containing biphenyl structure provided by the present invention has a mild synthesis process, simple synthesis technology and easy implementation. Under the specific technical conditions provided by the preparation method of the present invention, the target product with high yield can be prepared. Attached Figure Description

[0021] Figure 1 This is the FTIR spectrum of the biphenyl polyamine compound; Figure 2 This is the GPC diagram of the biphenyl polyamine compound; Figure 3 This is the FTIR spectrum of benzoxazine obtained in Example 1; Figure 4 This is the DSC spectrum of the benzoxazine obtained in Example 1; Figure 5 This is the FTIR spectrum of the benzoxazine obtained in Example 2; Figure 6 This is the DSC spectrum of the benzoxazine obtained in Example 2; Figure 7 This is the FTIR spectrum of benzoxazine obtained in Example 3; Figure 8 This is the DSC spectrum of the benzoxazine obtained in Example 3; Figure 9 This is the FTIR spectrum of the benzoxazine obtained in Example 4; Figure 10 This is the DSC spectrum of the benzoxazine obtained in Example 4. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0023] The GPC chromatogram mentioned above refers to a gel permeation chromatogram; the DSC chromatogram refers to a differential scanning calorimetry chromatogram; and the FTIR chromatogram refers to an infrared spectrum.

[0024] The biphenyl polyamine compound in this application can be synthesized using the same method as described in Japanese Patent Publication No. 8-16151 and Japanese Patent Publication No. 5030297, which involves the reaction of aniline with a dihalomethylaralkyl derivative or an aralkyl alcohol derivative. The FTIR chromatogram of the self-prepared biphenyl polyamine compound in this application is shown below. Figure 1 As shown, the GPC chromatogram of the obtained benzidine polyamine compound is as follows. Figure 2 As shown.

[0025] The embodiments of the present invention will be described in detail below with reference to specific examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0026] Example 1 This embodiment provides a method for preparing a polyfunctional benzoxazine containing a biphenyl structure, comprising: placing 63 g of paraformaldehyde, 114.1 g of 2,2-bis(4-hydroxyphenyl)propane (BPA), and 110 g of toluene into a 1000 ml round-bottom flask, stirring at 200 rpm for 15 min to obtain a mixture; heating the mixture to 75 °C, then adding the biphenyl polyamine compound in five equal portions, 9.04 g each time, and finally adding 74.5 g of aniline dropwise, stirring at 80 °C for 3 h; after the reaction is completed and cooled to room temperature, filtering the obtained mixture, removing the solvent from the filtrate using a rotary evaporator, and drying the obtained solid in a vacuum oven at 60 °C for 12 h to obtain a black solid with a yield of 87%. The chemical reaction equation is as follows: In this embodiment, the structure of the obtained product is shown in formula A1: Formula A1 The FTIR and DSC spectra of the product are as follows: Figure 3 and Figure 4 As shown; from Figure 3 It can be seen that it is 947 cm. -1 and 1232 cm -1 The characteristic absorption peak of the benzoxazine ring is located at [position missing]; from [location missing] Figure 4 It can be seen that the peak temperature of the exothermic curing of benzoxazine monomer is 248.6℃.

[0027] Example 2 This embodiment provides a method for preparing a multifunctional benzoxazine containing a biphenyl structure, which differs from Example 1 in that BPA is replaced with 4,4-dihydroxydiphenylmethane (BPF), wherein the specific chemical structural formula of BPF is as follows: The reactants were: 45.2 g of biphenyl polyamine, 74.5 g of aniline, 100.1 g of BPF, 63 g of paraformaldehyde, and 105 g of toluene. The yield of the product was 89%. The chemical reaction equation is as follows: In this embodiment, the structure of the obtained product is shown in formula A2: Formula A2 The FTIR and DSC spectra of the product are as follows: Figure 5 and Figure 6 As shown; from Figure 5 It can be seen that it is 947 cm. -1 and 1227 cm -1 The characteristic absorption peak of the benzoxazine ring is located at [position missing]; from [location missing] Figure 6 It can be seen that the peak exothermic temperature of the benzoxazine monomer obtained in this embodiment is 248.3℃.

[0028] Example 3 This embodiment provides a method for preparing a multifunctional benzoxazine containing a biphenyl structure, which differs from Example 1 in that BPA is replaced with 4,4'-dihydroxydiphenyl sulfone (BPS), wherein the specific chemical structural formula of BPS is as follows: The reactants were: 45.2 g of biphenyl polyamine, 74.5 g of aniline, 125.1 g of BPS, 63 g of paraformaldehyde, and 116 g of toluene. The yield of the product was 80%. The chemical reaction equation is as follows: In this embodiment, the structure of the obtained product is shown in formula A3: Formula A3 The FTIR and DSC spectra of the product are as follows: Figure 7 and Figure 8 As shown; from Figure 7 It can be seen that it is 925 cm. -1 and 1238 cm -1 The characteristic absorption peak of the benzoxazine ring is located at [position missing]; from [location missing] Figure 8 It can be seen that the peak exothermic temperature of the benzoxazine monomer obtained in this embodiment is 207.3℃.

[0029] Example 4 This embodiment provides a method for preparing a multifunctional benzoxazine containing a biphenyl structure, which differs from Example 1 in that aniline is replaced with furfurylamine, wherein the specific chemical structural formula of furfurylamine is as follows: The reactants were: 114.1 g BPA, 45.2 g biphenyl polyamine, 77.7 g furfurylamine, 63 g paraformaldehyde, and 113 g toluene. The yield of the product was 80%. The chemical reaction equation is as follows: In this embodiment, the structure of the obtained product is shown in Formula A4: Formula A4 The FTIR and DSC spectra of the product are as follows: Figure 9 and Figure 10 As shown; from Figure 9 It can be seen that 935 cm -1 and 1230 cm -1 The characteristic absorption peak of the benzoxazine ring is located at [position missing]; from [location missing] Figure 10 It can be seen that the peak exothermic temperature of the benzoxazine monomer obtained in this embodiment is 246.3℃.

[0030] Example 5 This embodiment provides a method for preparing a multifunctional benzoxazine containing a biphenyl structure, which differs from Example 1 in that BPA is replaced with 4-[(3-chloro-4-hydroxyphenyl)methyl]phenol (Monochloro-BPF) and aniline is replaced with methylamine. The specific chemical structural formula of Monochloro-BPF is as follows: The specific chemical structural formula of methylamine is: The reactants were: 45.2 g of biphenyl polyamine, 24.84 g of methylamine, 117.34 g of monochloro-BPF, 63 g of paraformaldehyde, and 91 g of toluene. The yield of the product was 80%. The chemical reaction equation is as follows: In this embodiment, the structure of the obtained product is shown in Formula A5: Formula A5 The product was at 936 cm. -1 and 1238 cm -1 The peak value is the characteristic absorption peak of the benzoxazine ring, and the curing exothermic peak temperature is 198.4℃.

[0031] Example 6 This embodiment provides a method for preparing a multifunctional benzoxazine containing a biphenyl structure, which differs from Example 1 in that BPA is replaced with 4-[2-(4-hydroxy-3-methylphenyl)prop-2-yl]-2-methylphenol (BPC), and aniline is replaced with cyclohexylamine. The specific chemical structural formula of BPC is as follows: The specific chemical structural formula of cyclohexylamine is: The reactants were: 45.2 g of biphenyl polyamine, 79.34 g of cyclohexylamine, 128.17 g of BPC, 63 g of paraformaldehyde, and 119 g of toluene. The yield of the product was 70%. The chemical reaction equation is as follows: In this embodiment, the structure of the obtained product is shown in formula A6: Formula A6 This product is located at 929 cm. -1 and 1230 cm -1 The peak value is the characteristic absorption peak of the benzoxazine ring, and the curing exothermic peak temperature is 239.5℃.

[0032] Experimental Example 1 The multifunctional benzoxazine monomers containing biphenyl structures prepared in Examples 1-6 were subjected to self-curing via heating to obtain a series of cured resin sheets. The specific preparation method is as follows: First, the benzoxazine monomers obtained in Examples 1-6 were uniformly poured into a mold. The temperature was increased from room temperature to 180°C at a rate of 4°C / min, and the pressure was increased from 0.5 MPa to 5 MPa at a rate of 0.1 MPa / min, maintaining the pressure for 2 hours. Then, the temperature was increased to 200°C and maintained for 2 hours, then to 220°C and maintained for 1 hour, then to 240°C and maintained for 1 hour, and finally to 260°C and maintained for 1 hour. After curing, the pressure was released and the mixture was allowed to cool naturally to room temperature. Demolding yielded the corresponding cured resin sheets.

[0033] The cured resin sheets containing biphenyl-containing multifunctional benzoxazine compounds obtained in Examples 1-6 were subjected to the following tests to verify their performance. The test results are shown in Table 1. The test items included: (1) Infrared testing: GB / T 6040-2019 standard was adopted, with a wavenumber range of 4000-400 cm⁻¹. -1 The resolution is 4cm. -1 ; (2) Peak temperature Tp: Differential scanning calorimetry (DSC) was used, according to the method specified in ISO 11357-5, with a heating rate of 10℃ / min and a frequency of 10Hz; (3) Dielectric constant (Dk): Determined according to the test method specified in IPC-TM-6502.5.5.9; (4) Dielectric loss factor (Df): Determined according to the test method specified in IPC-TM-6502.5.5.9.

[0034] As shown in Table 1, the copper-clad laminate prepared from the biphenyl-containing multifunctional benzoxazine provided in this application exhibits extremely excellent dielectric and thermal properties. These properties of the biphenyl-containing multifunctional benzoxazine prepared using this invention enable it to support the urgent needs of next-generation high-frequency, high-speed communication equipment for low-loss substrate materials, as well as aerospace vehicles for high-temperature resistant, ablation-resistant composite materials.

[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multifunctional benzoxazine containing a biphenyl structure, characterized in that: The multifunctional benzoxazine containing the biphenyl structure has the structure of formula A: Formula A Where n≥1, m≥1; R1 is selected from one of the following: -O-, -S-, -S(=O)-, -S(=O)2-, -C(=O-, or a hydrocarbon group with a substituent; R2 and R3 are each independently selected from one of hydrogen atoms, halogen atoms, alkyl groups having 1-8 carbon atoms, or aryl groups; R4 is selected from one of the following: alkyl, cycloalkyl, allyl, aryl and their derivatives, and furan, which have 1-10 carbon atoms.

2. A method for preparing a multifunctional benzoxazine containing a biphenyl structure as described in claim 1, characterized in that: include: Obtained by solvent polymerization of biphenyl polyamine compounds, amine compounds, phenolic compounds and aldehyde compounds; The biphenyl polyamine compound has the structure of formula B: Formula B Where n≥1; The amine compounds include monofunctional amine compounds; The phenolic compounds include bifunctional phenolic compounds; The aldehyde compounds include one of formaldehyde and / or paraformaldehyde, or an aqueous solution of formaldehyde.

3. The preparation method according to claim 2, characterized in that: The amine compound has the structure of formula C: Formula C R4 is selected from one of the following: alkyl, cycloalkyl, allyl, alkynyl, aryl and their derivatives, and furan, which have 1-10 carbon atoms.

4. The preparation method according to claim 2, characterized in that, The phenolic compound has the structure of formula D: Formula D R1 is selected from one of the following: -O-, -S-, -S(=O)-, -S(=O)2-, -C(=O)-, and a hydrocarbon group with a substituent; R2 and R3 are each independently selected from one of hydrogen atoms, halogen atoms, alkyl groups having 1-8 carbon atoms, or aryl groups.

5. The preparation method according to claim 2, characterized in that: Includes the following steps: The phenolic compound, the aldehyde compound, and the organic solvent are added to a round-bottom flask, heated to 75-80°C, and then the biphenyl polyamine compound is added in five equal portions, followed by the amine compound. Finally, the mixture is kept at 80-100°C for 120-360 minutes to obtain a mixed solution. The solution is filtered to remove the solvent from the filtrate, and then dried under vacuum to obtain the final product.

6. The preparation method according to claim 5, characterized in that: The molar ratio of the amino functional group of the biphenyl polyamine compound to the phenolic hydroxyl functional group of the phenolic compound is 1:1.1-10.

7. The preparation method according to claim 5, characterized in that: The molar ratio of the amino functional groups of the biphenyl polyamine compound and the amine compound to the aldehyde compound is 1:2-2.

5.

8. The preparation method according to claim 5, characterized in that: The molar ratio of the amino functional groups of the biphenyl polyamine compound to the amino functional groups of the amine compound is 1:0.1-9.

9. The preparation method according to claim 5, characterized in that: The organic solvent is selected from at least one of toluene, tetrahydrofuran, xylene, N,N-dimethylformamide, and 1,4-dioxane.

10. The preparation method according to claim 5, characterized in that: The total addition time for the biphenyl polyamine compound and the amine compound is 40-60 min.

11. The preparation method according to claim 5, characterized in that: When the amine compound is a liquid, it is added dropwise directly; when the amine compound is a solid, it is first dissolved into an amine compound solution before being added dropwise.

12. The preparation method according to claim 5, characterized in that: The conditions for vacuum drying of the solid are: temperature 60℃ and time 12h.

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