A high temperature resistant resin prepolymer and polymer for printed circuit board and preparation method thereof

Abstract

The present invention relates to a high-temperature-resistant resin prepolymer and polymer for printed circuit boards, and their preparation methods, belonging to the technical field of high-performance polymer preparation. This invention effectively addresses the high energy consumption and difficulty associated with the processing and molding of existing resin matrices for printed circuit boards, simplifies the polymer molding process, and improves the polymer's overall performance. It also provides a novel high-performance resin matrix for the field of high-performance printed circuit board materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of high-performance polymers, and in particular relates to a method for preparing a high-temperature resistant resin prepolymer and a polymer for a printed circuit board. Background Art

[0002] At present, electronic information technology is developing by leaps and bounds, and electronic products are becoming further miniaturized, lightweight and assembled with high density. Conventional polymer materials can no longer meet the requirements of use in terms of heat resistance, chemical resistance, dimensional stability, long-term reliability, etc. There is an urgent need to develop heat-resistant low-dielectric polymer materials with high glass transition temperature (Tg).

[0003] Epoxy resin is currently the most widely used resin matrix for printed circuit board materials. However, the poor temperature resistance, high dielectric constant and dielectric loss of traditional epoxy resins have severely limited their application in high-frequency and high-speed printed circuit board materials.

[0004] Although cyanate ester resins, a class of thermosetting resins with high-temperature resistance and low dielectric properties, have garnered widespread attention in recent years for applications such as wave-transmitting materials for weapons and equipment and low-dielectric materials for electronic information, their application in key sectors of the national economy has been severely limited by their strong water absorption, polymer brittleness, narrow processing temperature window, and high polymerization temperatures. However, the low dielectric properties and structural dimensional stability exhibited by cyanate ester resin polymers have made them attractive for use in high-frequency and high-speed printed circuit board materials. Structural studies of the performance advantages of cyanate ester resins have revealed that their superior properties stem from the cyclization polymerization of cyano groups within their structure. Inspired by this, improving the processing characteristics of cyanate ester resins through co-polymerization and modification, or developing new thermosetting resins containing cyano groups, is expected to provide new material types for high-temperature resistant printed circuit board materials.

[0005] Patent CN202211109917.6 discloses a low-temperature, fast-curing cyanate ester resin containing an amino group and a preparation method thereof. This method utilizes a catalyst to catalyze the cyanate ester resin to achieve low-temperature curing, improving its molding process. However, the catalyst structure contains halogen elements, which does not meet the material component requirements for printed circuit boards.

[0006] Patent CN201811355446.0 discloses a nitrile-based resin for high-frequency, high-speed copper-clad laminates and its preparation method. This method synthesizes a benzoxazine resin containing diphthalonitrile groups. By leveraging the reinforcement of glass fiber cloth and the strong bonding between the diphthalonitrile functional groups and copper foil, a high-temperature-resistant copper-clad laminate material is obtained. However, the copper-clad laminate material produced by this method has high dielectric loss and cannot meet the application requirements of high-performance printed circuit substrates.

[0007] Patent CN202010291777.3 discloses a lightweight, low-loss fiber-reinforced aromatic nitrile resin-based composite material and its preparation method. This method utilizes a copolymerization reaction between two diphthalonitrile resins to produce a highly heat-resistant polymer system through cyclization of cyano groups. However, the patent does not address the application of this highly heat-resistant resin in the field of printed circuit boards.

[0008] Therefore, how to provide a high-performance resin prepolymer or polymer material for printed circuit boards is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0009] It should be noted that existing materials for printed circuit boards primarily include epoxy resins and specialty resin systems. Epoxy resins, due to their mediocre heat resistance and dielectric properties, cannot meet the application requirements of high-frequency, high-speed printed circuit boards. Specialty resin systems, primarily cyanate ester resins, bismaleimide resins, and triazine resins, typically exhibit high curing temperatures and require blending, copolymerization, or the introduction of catalysts / curing agents to promote the polymerization of the resin matrix to achieve high-performance polymer systems.

[0010] Specifically, the following aspects of the existing printed circuit board materials can be improved during implementation:

[0011] 1) The resins currently used usually require melt processing to prepare prepolymers in order to improve the processability of the resin system. The melt prepolymerization process has problems such as high energy consumption, high risk, and difficulty in controlling the degree of prepolymerization;

[0012] 2) Existing resin polymer systems have significant deficiencies and are unable to meet the application requirements of printed circuit boards. For example, cyanate ester resins exhibit strong water absorption, resulting in significant environmental impact on the electrical properties of printed circuit boards. Excessive catalysis of bismaleimide resin polymers can lead to cracking and damage defects in printed circuit boards during subsequent circuit processing. Triazine resins generally have high molding temperatures, placing stringent requirements on equipment and consuming high energy.

[0013] 3) The curing agents and catalysts introduced in the existing process are usually compounds containing transition metals, halogen elements, etc., which are inherently unstable, have poor heat resistance, and cause residual metal particles and halogen elements in the resin polymer system components, resulting in failure to meet the application standards of high-performance printed circuit substrates.

[0014] In summary, existing resin systems have problems such as high energy consumption, complicated processes, and difficult to control polymer properties during the processing and molding process. They cannot meet the application requirements of high-performance printed circuit substrates and are not in line with the trend of energy conservation, emission reduction, green and sustainable development.

[0015] In view of this, the purpose of the present invention is to address the problems existing in the prior art and to propose a high temperature resistant resin prepolymer and polymer for printed circuit boards and a preparation method thereof.

[0016] In order to achieve the above object, the present invention provides the following technical solutions:

[0017] A method for preparing a high-temperature resistant resin prepolymer for a printed circuit board comprises the following steps:

[0018] 1) bisphenol fluorene, 2,6-dichlorobenzonitrile, potassium carbonate, N-methylpyrrolidone, and toluene are sequentially added to a three-necked flask. In the first stage, the temperature is slowly raised to 150-160° C. and the reaction is continued for 2-4 hours. In the second stage, the temperature is raised to 170-180° C. and the reaction is continued for 1-1.5 hours. The reaction is then stopped. When the system temperature drops to about 80-90° C., the reaction solution is transferred to an appropriate amount of deionized water to precipitate, which is repeatedly washed, filtered, and dried to obtain a diphenol with a novel structure.

[0019] The molar ratio of the solid material (bisphenol fluorene: 2,6-dichlorobenzonitrile: potassium carbonate) is 2.1-2.25:1:2.2, the mass ratio of the solid material to the solvent (N-methylpyrrolidone, toluene) is 1-1.2:1, the mass ratio of the solvent (N-methylpyrrolidone: toluene) is 6-8:1, and the mass ratio of deionized water to the reaction solution system is 2-3:1.

[0020] Regarding the choice of temperature for the first stage, above this temperature, the side reactions increase sharply, resulting in low product purity; below this temperature, the activity of the reactants is not enough to initiate the reaction;

[0021] Regarding the selection of the first stage reaction time, if it is longer than this time, the reaction efficiency is low, and if it is shorter than this time, the reaction is incomplete and the yield is low;

[0022] Regarding the selection of the temperature for the second stage, above this temperature, the phenolic hydroxyl groups are oxidized and destroyed, resulting in the reaction not being able to proceed according to the stoichiometric ratio and the product being uncontrollable; below this temperature, the hydroxyl groups do not react fully, resulting in residual halogen elements in the product;

[0023] Regarding the selection of the second stage reaction time, if it is longer than this time, the reaction efficiency is low, and if it is shorter than this time, the reaction is insufficient;

[0024] Regarding the choice of temperature at the end of the reaction, above this temperature, a large amount of solvent evaporates and escapes to pollute the environment, while below this temperature leads to low efficiency of the synthesis process or increased equipment cooling costs;

[0025] Regarding the selection of deionized water dosage, if the ratio is higher than this, it will easily cause waste of water resources and increase the difficulty of wastewater treatment; if the ratio is lower than this, the reaction product will not be fully precipitated, resulting in increased difficulty in separation;

[0026] Regarding the selection of the ratio of solid materials, deviation from this ratio will result in the inability to obtain the target structure product;

[0027] Regarding the selection of the ratio of solid material to solvent, if the ratio is higher than this, the solid material will be unevenly dispersed in the solvent, resulting in the reaction being unable to proceed according to the stoichiometric ratio; if the ratio is lower than this, solvent resources will be wasted and the subsequent solvent return cost will be increased;

[0028] Regarding the selection of solvent dosage ratio, if the ratio is higher than this, it will be difficult to control the temperature in the first stage and the temperature will easily soar. If the ratio is lower than this, the azeotropic point of the blended solvent system will be difficult to reach 170-180°C in the second stage, and the reaction system conditions cannot be met.

[0029] 2) Add dihydric phenol, aromatic amine, paraformaldehyde, anhydrous ethanol, and xylene to a three-necked flask in sequence, slowly heat to 80-95° C., continue the reaction for 3-5 hours, add a chain extender, raise the temperature to 110-130° C., continue the reaction for 1-4 hours, and remove the solvent in the system to obtain a resin prepolymer for a printed circuit board.

[0030] Among them, the molar ratio of the solid material (dihydric phenol: aromatic amine: paraformaldehyde) is 1:2.05~2.1:4~4.05, the mass ratio of the solid material to the solvent (anhydrous ethanol, xylene) is 1~1.4:1, the mass ratio of the solvent (anhydrous ethanol: xylene) is 1:2~2.5, and the mass of the chain extender is 5~8% of the theoretical mass of the product.

[0031] Furthermore, regarding the selection of reaction temperature, above this temperature, side reactions increase and the product purity is low, while below this temperature, the reaction efficiency is low;

[0032] Regarding time selection, if the time is longer than this, the synthesis efficiency is low, and if the time is shorter than this, the reaction degree is low, resulting in low yield;

[0033] Regarding the selection of the amount of chain extender, if the ratio is higher than this, the chain extender will undergo a self-polymerization reaction, resulting in phase separation of the final polymer and unstable product performance. If the ratio is lower than this, the chain extension of the resin prepolymer is insufficient, resulting in a low degree of polymer polymerization and poor performance. In addition, the chain extender is bisphenol A type cyanate. If other resins including epoxy resins, phenolic resins, etc. are used instead, the technical effects described in this article cannot be achieved.

[0034] Regarding the selection of reaction temperature, above this temperature, the chain extension prepolymerization reaction rate is too fast and uncontrollable; below this temperature, the chain extension prepolymerization reaction rate is slow and the chain extension effect is not ideal;

[0035] Regarding the choice of reaction time, if it is longer than this time, the degree of prepolymerization is too high, resulting in excessive viscosity of the system, which is not conducive to subsequent molding processing; if it is shorter than this time, the degree of prepolymerization is low and the polymer performance is poor;

[0036] Regarding the selection of the ratio of solid materials, if this ratio is deviated from, the reaction cannot proceed according to the preset route and the resin monomer with the target structure cannot be obtained;

[0037] Regarding the selection of the ratio of solid material to solvent, if the ratio is higher than this, the solid material will be unevenly dispersed in the solvent, resulting in the reaction being unable to proceed according to the stoichiometric ratio. If the ratio is lower than this, solvent resources will be wasted and the subsequent solvent return cost will be increased.

[0038] Regarding the selection of the solvent dosage ratio, if the polar solvent content is higher than this ratio, it will limit the cyclization reaction of the benzoxazine ring, resulting in low purity of the synthetic product. If the ratio is lower than this ratio, the highly polar aromatic amines and diphenols have poor solubility in the system, resulting in the synthesis reaction being unable to proceed according to the established ratio.

[0039] The structure of the high temperature resistant resin prepolymer for printed circuit substrate is shown in Formula 1:

[0040]

[0041] Wherein, the structure of dihydric phenol is shown in Formula 2:

[0042]

[0043] The structure of aromatic amine 4-amino (phenoxy) benzonitrile is shown in Formula 3.

[0044]

[0045] The present invention also seeks to protect a high-temperature resistant resin prepolymer for a printed circuit board prepared by the above method, wherein the resin prepolymer contains a cyano group and a benzoxazine ring, specifically:

[0046] A diphenol with a bifluorene chain segment is obtained by controlling the degree of affinity substitution reaction, and then an oxazine ring and a cyano group are introduced into the main chain structure through the Mannich cyclization reaction.

[0047] On the one hand, the large steric hindrance effect of the fluorene structure is utilized to reduce the dielectric constant and dielectric loss of the polymer, and on the other hand, the rich aromatic heterocycles in the difluorene structure are utilized to further improve the thermal stability of the polymer.

[0048] In addition, the introduction of oxazine rings and cyano groups can further increase the reaction sites of the resin matrix. By utilizing the addition reaction of the chain extender cyanate with the oxazine rings and cyano groups, the degree of cross-linking of the polymer can be improved while eliminating the polar phenolic hydroxyl and cyano groups generated and remaining in the resin monomer during the self-polymerization process. This can achieve the goal of improving the structural stability and thermal stability of the polymer while further improving its electrical properties, so that it can meet the requirements of printed circuit board materials under harsh conditions.

[0049] Therefore, the disclosure of the present invention can effectively solve the problems of high energy consumption and difficulty in the processing and molding of resin matrices for existing printed circuit boards, simplify the molding process of polymers, improve the comprehensive performance of polymers, and at the same time provide a new type of high-performance resin matrix for the field of high-performance printed circuit board materials.

[0050] Furthermore, the present invention further seeks to protect a polymer, which is obtained by coating the resin prepolymer prepared by the above method on a quartz glass slide and placing the prepolymer in a drying oven for heat treatment.

[0051] Furthermore, the resin prepolymer is coated on a quartz glass slide, and the heat treatment temperature is 170° C. to 220° C., and the time is 2-5 hours.

[0052] It can be seen from the above technical solutions that, compared with the prior art, the high-temperature resistant resin prepolymer and polymer for printed circuit boards and the preparation method thereof provided by the present invention have the following excellent effects:

[0053] 1) The present invention designs and prepares a new type of high-temperature resistant, high-performance thermosetting resin, which improves the problems of insufficient temperature resistance and complicated processing technology of existing resin systems;

[0054] 2) The present invention utilizes the synthetic process characteristics and structural features of the resin matrix to directly obtain the resin prepolymer through the chain extension reaction of the chain extender during the synthesis process, eliminating the need to use a solution or melting process or other thermal processing technology to prepare the prepolymer, thereby simplifying the production process and flow;

[0055] 3) The present invention utilizes the synergistic thermal polymerization effect of the active functional groups in the resin structure, without the need to introduce modifiers such as curing agents / accelerators. A resin polymer for printed circuit boards with outstanding thermal and electrical properties can be obtained through a simple heat treatment process, thereby simplifying the molding process and reducing production costs.

[0056] In summary, the process provided by the present invention is simple, efficient, low in energy consumption, and has outstanding polymer material performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0058] Figure 1 The figure is a comparison chart of thermal stability test of the high temperature resistant resin polymer for printed circuit substrate prepared in Example and Comparative Example.

[0059] Figure 2 The figure is a comparison chart of the dielectric properties test of the high temperature resistant resin polymer for the printed circuit substrate prepared in the embodiment and the comparative example. DETAILED DESCRIPTION

[0060] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention and the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0061] The embodiments of the present invention disclose a high-temperature resistant resin prepolymer and a polymer for a printed circuit board and a preparation method thereof.

[0062] For a better understanding of the present invention, the present invention is further specifically described below through the following examples, but it should not be understood as limiting the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above invention content are also considered to fall within the scope of protection of the present invention.

[0063] The technical solution of the present invention will be further described below in conjunction with specific embodiments.

[0064] Example 1

[0065] A resin prepolymer for a printed circuit board containing a cyano group and a benzoxazine ring is prepared according to the following steps:

[0066] A. 7.7 g of bisphenol fluorene, 1.71 g of 2,6-dichlorobenzonitrile, 3.036 g of potassium carbonate, 10.5 g of N-methylpyrrolidone, and 1.5 g of toluene were added to a three-necked flask in sequence. In the first stage, the temperature was slowly raised to 155 ° C. and the reaction was continued for 4 hours. In the second stage, the temperature was raised to 170 ° C. and the reaction was continued for 1.5 hours. The reaction was stopped. When the system temperature dropped to about 80-90 ° C., the reaction solution was transferred to 60 g of deionized water, the precipitate was precipitated, washed repeatedly, and filtered and dried to obtain a dihydric phenol with a novel structure;

[0067] B. Add 8.5 g of dihydric phenol, 4.35 g of aromatic amine, 1.20 g of paraformaldehyde, 3.4 g of anhydrous ethanol, and 6.8 g of xylene into a three-necked flask in sequence, slowly heat to 85° C., and continue to react for 4 hours. Then, add 0.56 g of chain extender, raise the temperature to 120° C., and continue to react for 2 hours. Remove the solvent in the system to obtain a resin prepolymer for printed circuit boards.

[0068] Wherein, the chain extender is bisphenol A cyanate ester.

[0069] (2) The resin prepolymer obtained in step (1) is coated on a quartz glass slide and placed in a drying oven for heat treatment at 200° C. for 4 h to obtain the polymer of the present invention.

[0070] The raw material dosage and process parameters of Examples 2-5 are shown in Table 1, and the remaining operations are the same as those of Example 1.

[0071] Table 1 Raw material dosage and process parameters of Examples 2-5

[0072] Raw material name and process parameters Example 2 Example 3 Example 4 Example 5 Bisphenol fluorene (g) 7.4 7.8 7.8 7.6 2,6-Dichlorobenzonitrile (g) 1.71 1.71 1.71 1.71 Potassium carbonate (g) 3.036 3.036 3.036 3.036 N-Methylpyrrolidone (g) 10.3 9.2 10.8 10.4 Toluene (g) 1.7 1.3 1.2 1.4 First stage temperature (℃) 160 150 160 155 First stage time (h) 2 3 4 2 Second stage temperature (℃) 175 180 180 175 Second stage time (h) 1 1 1.5 1.5 Water consumption for precipitation (g) 70 50 55 65 Dihydric phenol (g) 8.5 8.5 8.5 8.5 Aromatic amines (g) 4.40 4.36 4.33 4.40 Paraformaldehyde (g) 1.21 1.20 1.20 1.21 Anhydrous ethanol (g) 4.4 3.8 4.0 3.5 Xylene(g) 8.8 9.4 8.0 8.8 Reaction temperature (℃) 90 95 90 90 Reaction time (h) 3 4 5 3 Chain extender dosage (g) 0.6 0.8 0.7 0.8 Reaction temperature (℃) 130 110 130 120 Reaction time (h) 3 4 3 3 Heat treatment temperature (℃) 180 180 220 220 Heat treatment time (h) 5 5 2 3

[0073] The properties of the resin prepolymer and polymer prepared in each embodiment are as follows:

[0074] The dihydric phenol obtained in Example 1 was a uniform white powder. The obtained polymer film was uniform brown. The thermal decomposition temperature (T 5％ ) is 387℃, and the glass transition temperature (T g ) is 245°C, the dielectric constant is 3.2 (3GHz), and the dielectric loss is 0.006 (3GHz).

[0075] The dihydric phenol obtained in Example 2 was a uniform white powder. The obtained polymer film was uniform brown. The thermal decomposition temperature (T 5％ ) is 380℃, and the glass transition temperature (T g ) is 242°C, the dielectric constant is 3.2 (3GHz), and the dielectric loss is 0.006 (3GHz).

[0076] The dihydric phenol obtained in Example 3 was a uniform white powder. The obtained polymer film was uniform brown. The thermal decomposition temperature (T 5％ ) is 367℃, and the glass transition temperature (T g ) is 235°C, the dielectric constant is 3.1 (3GHz), and the dielectric loss is 0.005 (3GHz).

[0077] The dihydric phenol obtained in Example 4 was a uniform white powder. The obtained polymer film was uniformly black. The thermal decomposition temperature (T 5％ ) is 395℃, and the glass transition temperature (T g ) is 251°C, the dielectric constant is 3.1 (3GHz), and the dielectric loss is 0.005 (3GHz).

[0078] The dihydric phenol obtained in Example 5 was a uniform white powder. The obtained polymer film was uniformly black. The thermal decomposition temperature (T 5％) is 398℃, and the glass transition temperature (T g ) is 249°C, the dielectric constant is 3.0 (3GHz), and the dielectric loss is 0.005 (3GHz).

[0079] In addition, in order to further verify the superiority of the technical solution of the present invention over the prior art, the inventors also conducted the following comparative experiments, the specific contents of which are as follows:

[0080] The raw material dosage and process parameters of Comparative Examples 1-4 are shown in Table 2, and the remaining operations are the same as in Example 1.

[0081] Table 2 Raw material dosage and process parameters of Comparative Examples 1-4

[0082] Raw material name and process parameters Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Bisphenol fluorene (g) 7.0 7.6 7.6 7.8 2,6-Dichlorobenzonitrile (g) 1.71 1.71 1.71 1.71 Potassium carbonate (g) 3.036 3.036 3.036 3.036 N-Methylpyrrolidone (g) 9.7 10.4 10.4 10.8 Toluene (g) 1.4 1.4 1.4 1.2 First stage temperature (℃) 160 130 155 160 First stage time (h) 3 4 4 4 Second stage temperature (℃) 175 175 180 180 Second stage time (h) 1 1 1.5 1.5 Water consumption for precipitation (g) 60 60 65 55 Dihydric phenol (g) 8.5 - 8.5 8.5 Aromatic amines (g) 437 - 4.40 4.33 Paraformaldehyde (g) 1.20 - 1.21 1.20 Anhydrous ethanol (g) 3.7 - 4.4 4.0 Xylene(g) 9.4 - 8.8 8.0 Reaction temperature (℃) 90 - 75 90 Reaction time (h) 4 - 3 5 Chain extender dosage (g) 0.75 - 0.6 0.7 Reaction temperature (℃) 120 - 130 100 Reaction time (h) 2 - 3 4 Heat treatment temperature (℃) 200 - 200 220 Heat treatment time (h) 3 - 4 2

[0083] Furthermore, the properties of the resin prepolymer and polymer prepared in each comparative example are as follows:

[0084] The dihydric phenol obtained in Comparative Example 1 was a light yellow granular powder. The obtained polymer film was uniformly black. The thermal decomposition temperature (T 5％ ) is 389℃, and the glass transition temperature (T g ) is 253°C, the dielectric constant is 3.4 (3GHz), and the dielectric loss is 0.006 (3GHz).

[0085] In Comparative Example 2, no dihydric phenol was obtained. When the dihydric phenol synthesis reaction was completed and the product was transferred to water for precipitation, an oily substance was obtained. The oily substance could not be separated by washing with water, and the subsequent preparation of the resin prepolymer and polymer could not be performed.

[0086] The dihydric phenol obtained in Comparative Example 3 was a uniform white powder, and the obtained polymer film was uniformly black. The thermal decomposition temperature (T 5％ ) is 356℃, and the glass transition temperature (T g ) is 228°C, the dielectric constant is 3.4 (3 GHz), and the dielectric loss is 0.007 (3 GHz). Bubbling is very likely to occur during the preparation of polymer films, and vacuum equipment is required to remove the bubbles to obtain film samples suitable for testing.

[0087] The dihydric phenol obtained in Comparative Example 4 was a uniform white powder, and the obtained polymer film was uniformly black. However, due to the great brittleness of the film sample, it was impossible to obtain a sample that met the requirements of the static thermomechanical method test. The thermal decomposition temperature (T 5％ ) is 388°C, the dielectric constant is 3.5 (3GHz), and the dielectric loss is 0.006 (3GHz).

[0088] Furthermore, the molding temperature and time of the dihydric phenol and resin film polymer prepared in the above Examples 1-5 indicate that the processing conditions of the resin prepolymer are simple and the molding process of the polymer is simple and efficient; the thermal decomposition temperature and glass transition temperature of the polymer can be used to illustrate the thermal stability and high-temperature applicability of the polymer; the higher the thermal decomposition temperature, the better the thermal stability of the polymer; the higher the glass transition temperature, the better the service performance of the polymer in a high-temperature environment; the dielectric constant and dielectric loss of the polymer can be used to illustrate the electrical properties of the resin polymer and the applicability of printed circuit substrates; the lower the dielectric constant and the lower the dielectric loss, the greater the advantage of the resin polymer in being used for high-frequency and high-speed printed circuit substrates.

[0089] Furthermore, comparative experiments were conducted in four aspects: the ratio of dihydric phenol synthesis raw materials, reaction temperature, the synthesis reaction temperature of the resin monomer, and the reaction temperature of the resin prepolymer. The results showed that the ratio of dihydric phenol synthesis raw materials seriously affected the color state of the dihydric phenol and the dielectric properties of the polymer; the synthesis reaction temperature of the dihydric phenol was directly related to whether the target product could be obtained; the synthesis reaction temperature of the resin monomer also directly affected the cyclization rate of the resin monomer, resulting in the occurrence of foaming during the polymer preparation process, and ultimately affecting the dielectric properties of the polymer; the reaction temperature of the resin prepolymer directly affected the chain extension reaction of the resin system and affected the dielectric properties of the polymer.

[0090] Figure 1 The thermal stability test results of the polymers in the examples are shown below. All examples exhibit outstanding thermal performance. The glass transition temperature of the polymer obtained in Example 3 is lower than that of the other examples. This is primarily due to the relatively low prepolymerization temperature after the introduction of the chain extender, which results in a low degree of chain growth in the resin system. Furthermore, the curing temperature in the subsequent molding and polymerization stage is relatively low. The combined effect is manifested in a low degree of crosslinking in the polymers and a large range of motion of the chain segments under high temperature conditions, which is manifested as a low glass transition temperature. The outstanding thermal stability of Examples 1, 2, 4, and 5 is primarily due to the high degree of prepolymerization or polymerization during the preparation of the polymers.

[0091] Figure 2 The electrical performance test results of the example polymers show that all the example polymers have dielectric constants and dielectric losses that meet the application requirements, while the dielectric constants and dielectric losses of the comparative examples are significantly higher than those of the examples, and cannot meet the application requirements of high-frequency printed circuit substrate materials.

[0092] The main reasons are as follows: 1) the adjustment of the raw material ratio in the comparative example results in that the synthesis of the dihydric phenol cannot be carried out according to the stoichiometric ratio, and the structural composition of the obtained dihydric phenol is uncontrollable, which manifests as uncontrollable synthesis reaction process in the subsequent resin preparation process, and ultimately leads to uncontrollable structural composition of the resin prepolymer and the polymer, thereby affecting the electrical properties of the polymer; 2) the synthesis temperature of the resin monomer in the comparative example is relatively low, resulting in a complex resin structure composition, and the uncontrollable polymer structure leads to large fluctuations in dielectric properties; 3) after the chain extender is introduced, the prepolymerization reaction temperature is too low, resulting in an inability of the chain extender to undergo an effective chain growth reaction with the resin matrix, ultimately leading to obvious self-polymerization and phase separation of the resin system during the polymerization process, which significantly deteriorates the dielectric properties of the resin polymer.

[0093] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a high temperature resistant resin prepolymer for a printed circuit board, characterized in that: The method specifically comprises the following steps: 1) mixing bisphenol fluorene, 2,6-dichlorobenzonitrile, potassium carbonate and solvent I, heating the mixture to react, and after the reaction is completed, lowering the system temperature to 80° C. to 90° C., then transferring the reaction solution into deionized water to precipitate the precipitate, repeatedly washing the precipitate, and filtering and drying the precipitate to obtain a diphenol with a novel structure; The temperature-raising reaction in step 1) is performed as follows: in the first stage, the temperature is slowly raised to 150° C. to 160° C., and the reaction is continued for 2 to 4 hours; in the second stage, the temperature is raised to 170° C. to 180° C., and the reaction is continued for 1 to 1.5 hours, and the reaction is stopped; The structural formula of the dihydric phenol is as follows: ； The molar ratio of the bisphenol fluorene, 2,6-dichlorobenzonitrile and potassium carbonate is (2.1-2.25):1:2.2, and the amount of the solvent I added is 0.8-1 times the total mass of the bisphenol fluorene, 2,6-dichlorobenzonitrile and potassium carbonate; and the solvent I is composed of N-methylpyrrolidone and toluene in a mass ratio of (6-8):1; 2) mixing the dihydric phenol, aromatic amine, and paraformaldehyde prepared in step 1) with solvent II, slowly heating the mixture, then adding a chain extender and continuing the temperature reaction, and removing the solvent from the system after the reaction is complete to obtain the high-temperature resistant resin prepolymer for the printed circuit board; The structure of the high temperature resistant resin prepolymer for printed circuit board is as follows: ； The molar ratio of the dihydric phenol, aromatic amine and paraformaldehyde is 1:(2.05-2.1):(4-4.05), the amount of the solvent II added is 0.6-1 times the total mass of the dihydric phenol, aromatic amine and paraformaldehyde; and the solvent II is composed of anhydrous ethanol and xylene in a mass ratio of 1:(2-2.5); The chain extender is bisphenol A cyanate ester, and the mass of the chain extender is 5-8% of the theoretical mass of the product; The temperature-raising reaction in step 2) is performed as follows: slowly heating to 80° C. to 95° C., continuing the reaction for 3 to 5 hours, adding a chain extender, raising the temperature to 110° C. to 130° C., and continuing the reaction for 1 to 4 hours.

2. The method for preparing a high temperature resistant resin prepolymer for a printed circuit board according to claim 1, characterized in that: In step 1), the mass ratio of the deionized water to the reaction solution is (2-3):

1.

3. A high temperature resistant resin prepolymer for a printed circuit board prepared by the method according to claim 1, characterized in that: The resin prepolymer contains cyano groups and benzoxazine rings. Specifically, a diphenol with a bifluorene chain segment is obtained by controlling the degree of affinity substitution reaction, and then an oxazine ring and a cyano group are introduced into the main chain structure through a Mannich cyclization reaction.

4. A polymer, characterized in that The polymer is obtained by coating the resin prepolymer prepared by the method according to claim 1 or the resin prepolymer according to claim 3 on a quartz glass slide and placing the resultant product in a drying oven for heat treatment.

5. The polymer according to claim 4, characterized in that The resin prepolymer is coated on a quartz glass slide and heat-treated at a temperature of 170° C. to 220° C. for 2 to 5 hours.

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