Phosphorus-containing phenolic resin as well as preparation method and application thereof

Abstract

The invention provides phosphorus-containing phenolic resin as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The raw material components of the phenolic resin are designed, the boron-containing first mixture is matched with the silicon, nitrogen and benzene ring-containing second mixture to react with the aldehyde compound, and the phosphorus element is introduced through (methoxymethyl) diphenylphosphine oxide, so that the prepared phosphorus-containing phenolic resin has higher thermal degradation temperature and thermal deformation temperature, and the service life of the phenolic resin is prolonged. And the flame retardant property is effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a phosphorus-containing phenolic resin and a preparation method and application thereof. Background Art

[0002] Phenolic resin (PF) is a type of high molecular polymer formed by the condensation polymerization of phenolic compounds and aldehyde compounds under the catalysis of acidic or alkaline catalysts. Among them, phenolic resin formed by the condensation polymerization of phenol and formaldehyde is the most common and has the longest industrial production time. As one of the earliest artificial synthetic resins, phenolic resin can be used as adhesives, fireproof materials, insulating materials, friction materials and ablation-resistant materials because of its easy availability of raw materials, simple synthesis process, easy control of production conditions, and excellent mechanical properties and electrical insulation after curing. It is widely used in various fields closely related to the national economy, such as construction, electronics, machinery, aerospace and bonding. With the continuous development of industrial technology, people's requirements for material performance are getting higher and higher, so new demands are also put forward for phenolic resin.

[0003] A Chinese patent (publication number CN105754287A) discloses a high-performance phosphorus-containing phenolic resin. By combining two different phosphorus-containing phenolic resins together through the fusion of modified components, a high-performance phenolic resin is formed. The phosphorus content is increased, and the phosphorus element is introduced into the phenolic resin without affecting the mechanical properties of the resin itself. The introduction of the phosphorus element also avoids the high softening point of the product affecting the mechanical properties of the resin. However, the existing phenolic resin still has problems such as poor high temperature resistance, low thermal degradation temperature and heat deformation temperature, and the flame retardant performance needs to be improved.

[0004] Therefore, how to design the components, introduce groups that can withstand high temperatures, and use multiple elements to synergize flame retardancy so that the prepared phenolic resin has a higher thermal degradation temperature and heat deformation temperature and improves flame retardancy has become a direction that needs to be focused on. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a phosphorus-containing phenolic resin and a preparation method and application thereof, aiming to solve the problems that the existing phenolic resin has poor high temperature resistance, low thermal degradation temperature and thermal deformation temperature, and the flame retardant performance needs to be improved.

[0006] The present invention designs the raw material components of the phenolic resin, uses a first mixture containing boron, and cooperates with a second mixture containing silicon, nitrogen and benzene rings to react with aldehyde compounds, and introduces the phosphorus element through (methoxymethyl) diphenylphosphine, so that the prepared phosphorus-containing phenolic resin has a higher thermal degradation temperature and heat deformation temperature, and effectively improves the flame retardant performance.

[0007] The technical solution adopted by the present invention to solve the above technical problems is as follows: The first aspect of the present invention provides a method for preparing a phosphorus-containing phenolic resin, comprising the following steps: Step S1: by weight, 20 to 30 parts of phenol, 3 to 5 parts of toluene and 5 to 8 parts of boric acid are uniformly mixed to perform a first pre-reaction, and after the first pre-reaction is completed, the temperature is lowered to 90° C. to obtain a first mixture; Step S2: Mix 20-30 parts of phenol and 5-10 parts of aniline methyl trimethoxy silane by weight, stir them evenly, then add 0.3-0.5 parts of catalyst, carry out a second pre-reaction under the protection of nitrogen atmosphere, and cool the temperature to 90° C. after the second pre-reaction is completed to obtain a second mixture; Step S3: by weight, 20 to 30 parts of the first mixture, 20 to 30 parts of the second mixture and 15 to 20 parts of the aldehyde compound are mixed to carry out a polymerization reaction, and after the polymerization reaction is completed, a prepolymer system is obtained; Step S4: adding 30 to 40 parts by weight of a phosphorus-containing compound to the prepolymerization system for an addition reaction, and after the addition reaction is completed, adding 3 to 5 parts of carbon quantum dot-modified antimony trioxide and 3 to 5 parts of an aluminum chloride complex, mixing them evenly, to obtain a phosphorus-containing phenolic resin.

[0008] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0009] As a preferred technical solution of the present invention, the reaction temperature of the first pre-reaction is 160-165° C., and the reaction time is 2-3 hours.

[0010] The first mixture contains boron element, and subsequent reactions can introduce boron into the phenolic resin. Boron element generates boron oxide during high-temperature combustion, which can adhere to the surface of the burning material to form a dense barrier layer, which can isolate the spread of heat and combustible gas during the combustion process, causing the material to self-extinguish, while reducing its smoke production, thereby improving the flame retardant effect.

[0011] As a preferred technical solution of the present invention, the catalyst in step S2 is a Bronsted acid catalyst.

[0012] As a preferred technical solution of the present invention, the reaction temperature of the second pre-reaction in step S2 is 155-160° C., and the reaction time is 5-6 hours.

[0013] The second mixture contains silicon, nitrogen and benzene rings. The silicon element has a low surface energy and can easily migrate to the surface of the material to form a silicon-containing protective layer, thereby improving the high-temperature stability of the material. The nitrogen element can produce flame-retardant nitrogen-containing compounds at high temperatures to dilute the concentration of the combustion gas near the flame and exert a flame retardant effect. The benzene ring can hinder the movement of the molecular chain, reduce thermal expansion, and increase the thermal deformation temperature of the material.

[0014] Preferably, the aldehyde compound in step S3 is paraformaldehyde.

[0015] Preferably, the reaction temperature of the polymerization reaction in step S3 is 90-110° C., and the reaction time is 1-3 h.

[0016] As a preferred technical solution of the present invention, the phosphorus-containing compound in step S4 is (methoxymethyl)diphenylphosphine.

[0017] As a preferred technical solution of the present invention, the reaction temperature of the addition reaction in step S4 is 119-121° C., and the reaction time is 2-3 h.

[0018] Phosphorus and benzene rings are introduced into phenolic resins through phosphorus-containing compounds. Phosphorus releases phosphorus oxide free radicals under high temperature conditions and combines with free radicals that promote combustion, thereby terminating the chain reaction of combustion and increasing the limiting oxygen index. The benzene ring has a rigid structure and can increase the packing density of the molecular chain, thereby reducing the free volume and effectively reducing the degree of thermal deformation.

[0019] As a preferred technical solution of the present invention, the preparation method of carbon quantum dot modified antimony trioxide described in step S4 includes: in parts by weight, 2 to 4 parts of itaconic acid are evenly spread on the bottom of a 50 ml beaker, and reacted in a vacuum drying oven at a reaction temperature of 200 to 220°C for a reaction time of 1 to 2 hours; after the reaction is completed, the solid is naturally cooled to room temperature to obtain a solid, and then 10 to 20 parts of 1 mol / L sodium hydroxide solution are added to the solid, and then 5 to 10 parts of antimony trioxide are added, stirred evenly, freeze-dried, and ground to obtain carbon quantum dot modified antimony trioxide.

[0020] As a preferred technical solution of the present invention, the preparation method of the aluminum chloride complex described in step S4 includes: adding 4 to 6 parts of aluminum chloride to 100 to 120 parts of deionized water, adding 0.5 to 0.8 parts of sodium carbonate and stirring for 20 to 30 minutes, and then adding 1 to 3 parts of acrylamide and 0.1 to 0.2 parts of ammonium cerium nitrate under a nitrogen atmosphere for reaction for 2 to 4 hours. After the reaction is completed, vacuum drying is performed to obtain an aluminum chloride complex.

[0021] The second aspect of the present invention provides a phosphorus-containing phenolic resin prepared by the method described in the first aspect.

[0022] The third aspect of the present invention provides an application of the phosphorus-containing phenolic resin prepared by the method described in the first aspect in the printed circuit board industry.

[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) In the present invention, phenol and aniline methyl trimethoxysilane react under the action of a Bronsted acid catalyst to generate a second mixture, and the silicon element in the second mixture is introduced into the phenolic resin by means of a subsequent reaction. The silicon element has a low surface energy and can easily migrate to the surface of the material to form a silicon-containing protective layer, thereby increasing the thermal degradation temperature of the material.

[0024] (2) Both the second mixture and the phosphorus-containing compound of the present invention contain benzene rings. The benzene rings have a rigid structure and can increase the packing density of the molecular chain, thereby reducing the free volume. At the same time, they hinder the movement of the molecular chain and reduce thermal expansion. The combined effect increases the thermal deformation temperature of the material.

[0025] (3) The phenolic resin of the present invention introduces elements such as boron, silicon, nitrogen, and phosphorus. The boron element generates boron oxide during high-temperature combustion, which can isolate the heat and combustible gas from spreading during the combustion process; the synergistic effect of the silicon and nitrogen elements is to generate a flame-retardant nitrogen-containing gas that exerts a flame retardant effect in the condensed phase and the gas phase; the synergistic effect of the phosphorus and silicon elements is to form a phosphorus-containing carbon layer and a silicon-containing protective layer to avoid oxidation of the carbon layer on the surface of the material. Through the combined action of the four elements of boron, silicon, nitrogen, and phosphorus, the limiting oxygen index of the phenolic resin is improved.

[0026] (4) During the preparation process of the carbon quantum dot modified antimony trioxide of the present invention, the CH bonds in itaconic acid are gradually oxidized to carboxyl groups, and some CC bonds are broken or reorganized. As the itaconic acid molecules are continuously carbonized, the surface carboxyl groups are continuously enriched to form itaconic acid carbon quantum dots, which are used to modify antimony trioxide, so that its surface is rich in groups such as hydroxyl groups and carboxyl groups. The aluminum chloride complex is modified by acrylamide to introduce amino groups. When used in combination with the carbon quantum dot modified antimony trioxide, the amino groups can combine with the hydroxyl groups and carboxyl groups rich in the carbon quantum dots, effectively increasing the thermal degradation temperature and thermal deformation temperature of the resin composition. At the same time, when the temperature rises, the antimony trioxide and the aluminum chloride complex can react to generate antimony halide vapor, which can dilute the combustible gas and cool the flame, thereby preventing combustion. DETAILED DESCRIPTION

[0027] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0028] The sources of some components in the embodiments and comparative examples are as follows: Phenol, CAS No. 108-95-2, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Toluene, CAS No. 108-88-3, purchased from Shanghai Lingfeng Chemical Reagent Co., Ltd.; Boric acid, CAS No. 11113-50-1, was purchased from Tianjin Damao Chemical Reagent Factory; Acetic acid, CAS No. 64-19-7, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Bronsted acid catalyst, product number S816962, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Anilinemethyltrimethoxysilane, CAS No. 77855-73-3, purchased from Shandong Baiqian Chemical Co., Ltd.; Paraformaldehyde, CAS No. 30525-89-4, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; (Methoxymethyl)diphenylphosphine oxide, CAS No. 4455-77-0, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Itaconic acid, product number PA54343, was purchased from Shanghai Chuangsai Technology Co., Ltd.; Sodium hydroxide, CAS No. 1310-73-2, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Antimony trioxide, product number FR-180, was purchased from Hunan Shanxing Antimony Industry Company; Aluminum chloride, CAS No. 7446-70-0, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Sodium carbonate, CAS No. 497-19-8, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Acrylamide, product number A8887, was purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; Cerium ammonium nitrate, CAS No. 16774-21-3, was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0029] Preparation of carbon quantum dot modified antimony trioxide: In parts by weight, 4 parts of itaconic acid are evenly spread on the bottom of a 50 ml beaker, and the reaction is carried out in a vacuum drying oven at a reaction temperature of 220°C for 2 hours; after the reaction is completed, the solid is naturally cooled to room temperature to obtain a solid, and then the solid is added with 20 parts of 1 mol / L sodium hydroxide solution, and then 10 parts of antimony trioxide are added, stirred evenly, freeze-dried, and ground to obtain carbon quantum dot modified antimony trioxide.

[0030] Preparation of aluminum chloride complex: by weight, 6 parts of aluminum chloride were added to 120 parts of deionized water, and then 0.8 parts of sodium carbonate were added and stirred for 30 minutes. Then, under a nitrogen atmosphere, 3 parts of acrylamide and 0.2 parts of ammonium cerium nitrate were added and reacted for 4 hours. After the reaction was completed, the aluminum chloride complex was obtained by vacuum drying.

[0031] Example 1 This embodiment provides a method for preparing a phosphorus-containing phenolic resin, comprising the following steps: Step S1: by weight, 30 parts of phenol, 5 parts of toluene and 8 parts of boric acid are uniformly mixed to carry out a first pre-reaction (reaction temperature is 165° C., reaction time is 2 h), and after the first pre-reaction is completed, the temperature is lowered to 90° C. to obtain a first mixture; Step S2: In parts by weight, 30 parts of phenol and 10 parts of aniline methyl trimethoxy silane were mixed and stirred uniformly, and then 0.5 parts of Bronsted acid catalyst were added, and a second pre-reaction was carried out under the protection of nitrogen atmosphere (reaction temperature was 160° C., reaction time was 5 h), and after the second pre-reaction was completed, the temperature was lowered to 90° C. to obtain a second mixture; Step S3: by weight, 30 parts of the first mixture, 30 parts of the second mixture and 20 parts of paraformaldehyde are mixed for polymerization reaction (the reaction temperature of the polymerization reaction is 110° C. and the reaction time is 1 hour), and a prepolymer system is obtained after the polymerization reaction is completed; Step S4: In parts by weight, 40 parts of (methoxymethyl) diphenylphosphine are added to the prepolymerization system for addition reaction (the reaction temperature of the addition reaction is 121° C. and the reaction time is 2 h). After the addition reaction is completed, 5 parts of carbon quantum dot-modified antimony trioxide and 5 parts of aluminum chloride complex are added and mixed evenly to obtain a phosphorus-containing phenolic resin.

[0032] Example 2 This embodiment provides a method for preparing a phosphorus-containing phenolic resin, comprising the following steps: Step S1: by weight, 20 parts of phenol, 3 parts of toluene and 5 parts of boric acid are uniformly mixed to carry out a first pre-reaction (reaction temperature is 160° C., reaction time is 3 h), and after the first pre-reaction is completed, the temperature is lowered to 90° C. to obtain a first mixture; Step S2: In parts by weight, 20 parts of phenol and 5 parts of aniline methyl trimethoxy silane were mixed and stirred evenly, and then 0.3 parts of Bronsted acid catalyst were added, and a second pre-reaction was carried out under the protection of nitrogen atmosphere (reaction temperature was 155° C., reaction time was 6 h), and after the second pre-reaction was completed, the temperature was lowered to 90° C. to obtain a second mixture; Step S3: by weight, 20 parts of the first mixture, 20 parts of the second mixture and 15 parts of paraformaldehyde are mixed for polymerization reaction (the reaction temperature of the polymerization reaction is 90° C. and the reaction time is 3 hours), and a prepolymer system is obtained after the polymerization reaction is completed; Step S4: In parts by weight, 30 parts of (methoxymethyl) diphenylphosphine are added to the prepolymerization system for addition reaction (the reaction temperature of the addition reaction is 119° C. and the reaction time is 3 h). After the addition reaction is completed, 3 parts of carbon quantum dot-modified antimony trioxide and 3 parts of aluminum chloride complex are added and mixed evenly to obtain a phosphorus-containing phenolic resin.

[0033] Example 3 This embodiment provides a method for preparing a phosphorus-containing phenolic resin, comprising the following steps: Step S1: by weight, 25 parts of phenol, 4 parts of toluene and 6 parts of boric acid were mixed evenly for a first pre-reaction (reaction temperature was 162° C., reaction time was 3 h), and after the first pre-reaction was completed, the temperature was lowered to 90° C. to obtain a first mixture; Step S2: In parts by weight, 25 parts of phenol and 8 parts of aniline methyl trimethoxy silane were mixed and stirred evenly, and then 0.4 parts of Bronsted acid catalyst were added, and a second pre-reaction was carried out under the protection of nitrogen atmosphere (reaction temperature was 158° C., reaction time was 5 h), and after the second pre-reaction was completed, the temperature was lowered to 90° C. to obtain a second mixture; Step S3: by weight, 25 parts of the first mixture, 25 parts of the second mixture and 18 parts of paraformaldehyde are mixed for polymerization reaction (the reaction temperature of the polymerization reaction is 100° C. and the reaction time is 2 h), and a prepolymer system is obtained after the polymerization reaction is completed; Step S4: In parts by weight, 35 parts of (methoxymethyl)diphenylphosphine are added to the prepolymerization system for addition reaction (the reaction temperature of the addition reaction is 120° C. and the reaction time is 3 h). After the addition reaction is completed, 4 parts of carbon quantum dot-modified antimony trioxide and 4 parts of aluminum chloride complex are added and mixed evenly to obtain a phosphorus-containing phenolic resin.

[0034] Comparative Example 1 This comparative example provides a method for preparing a phenolic resin, comprising the following steps: Step S1: by weight, 30 parts of phenol, 5 parts of toluene and 8 parts of acetic acid were mixed evenly for a first pre-reaction (reaction temperature was 165° C., reaction time was 2 h), and after the first pre-reaction was completed, the temperature was lowered to 90° C. to obtain a first mixture; Step S2: In parts by weight, 30 parts of phenol and 10 parts of aniline methyl trimethoxy silane were mixed and stirred uniformly, and then 0.5 parts of Bronsted acid catalyst were added, and a second pre-reaction was carried out under the protection of nitrogen atmosphere (reaction temperature was 160° C., reaction time was 5 h), and after the second pre-reaction was completed, the temperature was lowered to 90° C. to obtain a second mixture; Step S3: by weight, 30 parts of the first mixture, 30 parts of the second mixture and 20 parts of paraformaldehyde are mixed for polymerization reaction (the reaction temperature of the polymerization reaction is 110° C. and the reaction time is 1 hour), and a prepolymer system is obtained after the polymerization reaction is completed; Step S4: In parts by weight, 40 parts of (methoxymethyl) diphenylphosphine are added to the prepolymerization system for addition reaction (the reaction temperature of the addition reaction is 121° C. and the reaction time is 2 h). After the reaction is completed, 5 parts of carbon quantum dot-modified antimony trioxide and 5 parts of aluminum chloride complex are added and mixed evenly to obtain a phosphorus-containing phenolic resin.

[0035] Comparative Example 2 This comparative example provides a method for preparing a phenolic resin, comprising the following steps: Step S1: by weight, 30 parts of phenol, 5 parts of toluene and 8 parts of boric acid are uniformly mixed to carry out a first pre-reaction (reaction temperature is 165° C., reaction time is 2 h), and after the first pre-reaction is completed, the temperature is lowered to 90° C. to obtain a first mixture; Step S2: by weight, 30 parts of the first mixture, 30 parts of phenol and 20 parts of paraformaldehyde are mixed for polymerization reaction (the polymerization temperature is 110° C. and the reaction time is 1 h), and a prepolymer system is obtained after the polymerization reaction is completed; Step S3: In parts by weight, 40 parts of (methoxymethyl) diphenylphosphine are added to the prepolymerization system for addition reaction (the reaction temperature of the addition reaction is 121° C. and the reaction time is 2 h). After the reaction is completed, 5 parts of carbon quantum dot-modified antimony trioxide and 5 parts of aluminum chloride complex are added and mixed evenly to obtain a phosphorus-containing phenolic resin.

[0036] Comparative Example 3 This comparative example provides a method for preparing a phenolic resin, comprising the following steps: Step S1: by weight, 30 parts of phenol, 5 parts of toluene and 8 parts of boric acid are uniformly mixed to carry out a first pre-reaction (reaction temperature is 165° C., reaction time is 2 h), and after the first pre-reaction is completed, the temperature is lowered to 90° C. to obtain a first mixture; Step S2: In parts by weight, 30 parts of phenol and 10 parts of aniline methyl trimethoxy silane were mixed and stirred uniformly, and then 0.5 parts of Bronsted acid catalyst were added, and a second pre-reaction was carried out under the protection of nitrogen atmosphere (reaction temperature was 160° C., reaction time was 5 h), and after the second pre-reaction was completed, the temperature was lowered to 90° C. to obtain a second mixture; Step S3: In parts by weight, 30 parts of the first mixture, 30 parts of the second mixture and 20 parts of paraformaldehyde are mixed for polymerization reaction (the reaction temperature of the polymerization reaction is 110°C, and the reaction time is 1h). After the polymerization reaction is completed, a prepolymer system is obtained; the temperature of the prepolymer system is increased to 120°C, and the reaction is continued for 4h. After the reaction is completed, 5 parts of carbon quantum dot-modified antimony trioxide and 5 parts of aluminum chloride complex are added, and the mixture is mixed evenly to obtain a phosphorus-containing phenolic resin.

[0037] Comparative Example 4 This comparative example provides a method for preparing a phenolic resin, comprising the following steps: Step S1: by weight, 30 parts of phenol, 5 parts of toluene and 8 parts of boric acid are uniformly mixed to carry out a first pre-reaction (reaction temperature is 165° C., reaction time is 2 h), and after the first pre-reaction is completed, the temperature is lowered to 90° C. to obtain a first mixture; Step S2: In parts by weight, 30 parts of the first mixture, 30 parts of phenol and 20 parts of paraformaldehyde are mixed for polymerization reaction (the reaction temperature of the polymerization reaction is 110° C., and the reaction time is 1 hour). After the polymerization reaction is completed, a prepolymerization system is obtained; the temperature of the prepolymerization system is increased to 120° C., and the reaction is continued for 4 hours. After the reaction is completed, 5 parts of carbon quantum dot-modified antimony trioxide and 5 parts of aluminum chloride complex are added, and the mixture is mixed evenly to obtain a phosphorus-containing phenolic resin.

[0038] Comparative Example 5 This comparative example provides a method for preparing a phenolic resin, comprising the following steps: Step S1: by weight, 30 parts of phenol, 5 parts of toluene and 8 parts of acetic acid were mixed evenly for a first pre-reaction (reaction temperature was 165° C., reaction time was 2 h), and after the first pre-reaction was completed, the temperature was lowered to 90° C. to obtain a first mixture; Step S2: In parts by weight, 30 parts of phenol and 10 parts of aniline methyl trimethoxy silane were mixed and stirred uniformly, and then 0.5 parts of Bronsted acid catalyst were added, and a second pre-reaction was carried out under the protection of nitrogen atmosphere (reaction temperature was 160° C., reaction time was 5 h), and after the second pre-reaction was completed, the temperature was lowered to 90° C. to obtain a second mixture; Step S3: In parts by weight, 30 parts of the first mixture, 30 parts of the second mixture and 20 parts of paraformaldehyde are mixed for polymerization reaction (the reaction temperature of the polymerization reaction is 110° C., and the reaction time is 1 hour). After the polymerization reaction is completed, a prepolymerization system is obtained; the temperature of the prepolymerization system is increased to 120° C., and the reaction is continued for 4 hours. After the reaction is completed, 5 parts of carbon quantum dot-modified antimony trioxide and 5 parts of aluminum chloride complex are added and mixed evenly to obtain a phosphorus-containing phenolic resin.

[0039] Comparative Example 6 This comparative example provides a method for preparing a phenolic resin, comprising the following steps: Step S1: by weight, 30 parts of phenol, 5 parts of toluene and 8 parts of acetic acid were mixed evenly for a first pre-reaction (reaction temperature was 165° C., reaction time was 2 h), and after the first pre-reaction was completed, the temperature was lowered to 90° C. to obtain a first mixture; Step S2: by weight, 30 parts of the first mixture, 30 parts of phenol and 20 parts of paraformaldehyde are mixed for polymerization reaction (the polymerization temperature is 110° C. and the reaction time is 1 h), and a prepolymer system is obtained after the polymerization reaction is completed; Step S3: In parts by weight, 40 parts of (methoxymethyl) diphenylphosphine are added to the prepolymerization system for addition reaction (the reaction temperature of the addition reaction is 121° C. and the reaction time is 2 h). After the addition reaction is completed, 5 parts of carbon quantum dot-modified antimony trioxide and 5 parts of aluminum chloride complex are added and mixed evenly to obtain a phosphorus-containing phenolic resin.

[0040] Comparative Example 7 This comparative example provides a method for preparing a phenolic resin, which is different from Example 1 in that carbon quantum dot-modified antimony trioxide is not added in step S4, and other conditions are the same as those in Example 1.

[0041] Comparative Example 8 This comparative example provides a method for preparing a phenolic resin, which is different from Example 1 in that no aluminum chloride complex is added in step S4, and other conditions are the same as those in Example 1.

[0042] Comparative Example 9 This comparative example provides a method for preparing a phenolic resin, which differs from Example 1 in that the carbon quantum dot-modified antimony trioxide and aluminum chloride complex is not added in step S4, and other conditions are the same as those in Example 1. The phenolic resin properties provided in the above examples and comparative examples are tested, and the test method is as follows: (1) Thermal degradation temperature test: A thermogravimetric analyzer (TA Instruments, TAInstruments Q500TGA, USA) was used to study the stability of the resin at high temperatures in a nitrogen environment. The test temperature ranged from room temperature to 800°C, with a heating rate of 20°C / min.

[0043] (2) Heat deformation temperature test: Test according to the requirements of GB / T 1634.2-2019 Determination of deformation temperature of plastics under load Part 2: Plastics and hard rubber.

[0044] (3) Flame retardancy test: Use the limiting oxygen index method and refer to the requirements of "GB / T 2406.3-2022 Plastics Determination of Combustion Behavior by Oxygen Index Method Part 3: High Temperature Test" for testing.

[0045] The above performance test data is shown in Table 1.

[0046] Table 1 Performance test results

[0047] From the above content, it can be seen that the phosphorus-containing phenolic resin (Example 1 to Example 3) prepared by the present invention through the design of components, the introduction of high temperature resistant groups, and the synergistic flame retardancy of multiple elements has a thermal degradation temperature of 478.1~478.2°C, a heat deformation temperature of 208.1~208.5°C, and a limiting oxygen index of 35.2~35.4%.

[0048] Compared with Example 1, acetic acid is used to replace boric acid, and the limiting oxygen index is reduced (Comparative Example 1); compared with Example 1, phenol is used to replace the second mixture, and the thermal degradation temperature, heat deformation temperature and limiting oxygen index are reduced (Comparative Example 2); compared with Example 1, (methoxymethyl) diphenyl phosphine is not used, and the heat deformation temperature and limiting oxygen index are reduced (Comparative Example 3); compared with Example 1, phenol is used to replace the second mixture, and (methoxymethyl) diphenyl phosphine is not used, and the thermal degradation temperature, heat deformation temperature and limiting oxygen index are reduced (Comparative Example 4); compared with Example 1, acetic acid is used to replace boric acid, and (methoxymethyl) diphenyl phosphine is not used, and the heat deformation temperature and limiting oxygen index are reduced. The index is reduced (Comparative Example 5); compared with Example 1, acetic acid is used to replace boric acid, and phenol is used to replace the second mixture, then the thermal degradation temperature, heat deformation temperature and limiting oxygen index are reduced (Comparative Example 6); compared with Example 1, step S4 does not add carbon quantum dot modified antimony trioxide, then the thermal degradation temperature, heat deformation temperature and limiting oxygen index are reduced (Comparative Example 7); compared with Example 1, step S4 does not add aluminum chloride complex, then the thermal degradation temperature, heat deformation temperature and limiting oxygen index are reduced (Comparative Example 8); compared with Example 1, step S4 does not add carbon quantum dot modified antimony trioxide and aluminum chloride complex, then the thermal degradation temperature, heat deformation temperature and limiting oxygen index are reduced (Comparative Example 9).

[0049] In summary, the present invention designs the raw material components of the phenolic resin, uses a first mixture containing boron, and cooperates with a second mixture containing silicon, nitrogen and benzene rings to react with aldehyde compounds, and introduces the phosphorus element through (methoxymethyl) diphenylphosphine, so that the prepared phosphorus-containing phenolic resin has a higher thermal degradation temperature and heat deformation temperature, and effectively improves the flame retardant properties.

[0050] The applicant declares that the present invention illustrates the detailed process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a phosphorus-containing phenolic resin, characterized in that: The following steps are involved: Step S1: by weight, 20 to 30 parts of phenol, 3 to 5 parts of toluene and 5 to 8 parts of boric acid are uniformly mixed to perform a first pre-reaction, and after the first pre-reaction is completed, the temperature is lowered to 90° C. to obtain a first mixture; Step S2: Mix 20-30 parts of phenol and 5-10 parts of aniline methyl trimethoxy silane by weight, stir them evenly, then add 0.3-0.5 parts of catalyst, carry out a second pre-reaction under the protection of nitrogen atmosphere, and cool the temperature to 90° C. after the second pre-reaction is completed to obtain a second mixture; Step S3: by weight, 20 to 30 parts of the first mixture, 20 to 30 parts of the second mixture and 15 to 20 parts of the aldehyde compound are mixed to carry out a polymerization reaction, and after the polymerization reaction is completed, a prepolymer system is obtained; Step S4: adding 30 to 40 parts by weight of a phosphorus-containing compound to the prepolymerization system for an addition reaction, and after the addition reaction is completed, adding 3 to 5 parts of carbon quantum dot-modified antimony trioxide and 3 to 5 parts of an aluminum chloride complex, mixing them evenly, to obtain a phosphorus-containing phenolic resin.

2. The method for preparing a phosphorus-containing phenolic resin according to claim 1, characterized in that: The reaction temperature of the first pre-reaction in step S1 is 160-165° C., and the reaction time is 2-3 h.

3. The method for preparing a phosphorus-containing phenolic resin according to claim 1, characterized in that: The catalyst in step S2 is a Bronsted acid catalyst; the reaction temperature of the second pre-reaction is 155-160° C., and the reaction time is 5-6 hours.

4. The method for preparing a phosphorus-containing phenolic resin according to claim 1, characterized in that: In step S3, the aldehyde compound is paraformaldehyde; the reaction temperature of the polymerization reaction is 90-110° C., and the reaction time is 1-3 hours.

5. The method for preparing a phosphorus-containing phenolic resin according to claim 1, characterized in that: The phosphorus-containing compound in step S4 is (methoxymethyl)diphenylphosphine.

6. The method for preparing a phosphorus-containing phenolic resin according to claim 1, characterized in that: The reaction temperature of the addition reaction in step S4 is 119-121° C., and the reaction time is 2-3 h.

7. The method for preparing a phosphorus-containing phenolic resin according to claim 1, characterized in that: The preparation method of carbon quantum dot modified antimony trioxide in step S4 includes: in parts by weight, 2 to 4 parts of itaconic acid are evenly spread on the bottom of a 50 ml beaker, and reacted in a vacuum drying oven at a reaction temperature of 200 to 220 ° C. The reaction time is 1 to 2 hours; after the reaction is completed, it is naturally cooled to room temperature to obtain a solid, and then the solid is added with 10 to 20 parts of 1 mol / L sodium hydroxide solution, and then 5 to 10 parts of antimony trioxide are added, stirred evenly, freeze-dried, and ground to obtain carbon quantum dot modified antimony trioxide.

8. The method for preparing a phosphorus-containing phenolic resin according to claim 1, characterized in that: The preparation method of the aluminum chloride complex in step S4 includes: adding 4 to 6 parts of aluminum chloride to 100 to 120 parts of deionized water, adding 0.5 to 0.8 parts of sodium carbonate and stirring for 20 to 30 minutes, and then adding 1 to 3 parts of acrylamide and 0.1 to 0.2 parts of ammonium cerium nitrate under a nitrogen atmosphere for reaction for 2 to 4 hours. After the reaction is completed, vacuum drying is performed to obtain an aluminum chloride complex.

9. A phosphorus-containing phenolic resin, characterized in that: The method is obtained by the preparation method according to any one of claims 1 to 8.

10. Application of the phosphorus-containing phenolic resin obtained according to the preparation method according to any one of claims 1 to 8 in the printed circuit board industry.

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