Boron nitride modified flame-retardant epoxy resin-based copper-clad plate and preparation method thereof

Abstract

The invention relates to the technical field of copper-clad plates, and particularly discloses a boron nitride modified flame-retardant epoxy resin-based copper-clad plate and a preparation method thereof. The flame-retardant epoxy resin-based copper-clad plate is prepared from the following materials in parts by mass: 45 to 55 parts of composite flame retardant, 100 to 120 parts of epoxy resin, 25 to 30 parts of diluent, 4 to 6 parts of epoxy polyhedral oligomeric silsesquioxane and 30 to 40 parts of curing agent, the preparation method comprises the following steps: mixing the modified boron nitride A and the modified boron nitride B in proportion to obtain a composite flame retardant; the preparation method comprises the following steps: respectively adding a diluent, epoxy polyhedral oligomeric silsesquioxane, a composite flame retardant and a curing agent into epoxy resin to obtain flame-retardant epoxy resin; the preparation method comprises the following steps: uniformly coating flame-retardant epoxy resin on ceramic fiber cloth, performing semi-curing, covering copper foil on the ceramic fiber cloth, and performing hot pressing and curing to obtain the flame-retardant epoxy resin-based copper-clad plate.

Description

Technical Field

[0001] The invention relates to the technical field of copper clad laminates, and particularly discloses a boron nitride-modified flame-retardant epoxy resin-based copper clad laminate and a preparation method thereof. Background Art

[0002] Epoxy resin is a common high molecular polymer with active epoxy groups in its molecules. It is easy to cure, has strong adhesion, excellent mechanical properties, and stable chemical properties at room temperature. It is often used as a coating and adhesive for surface encapsulation in the automotive, electronics, machinery and other industries. However, epoxy resin contains a large amount of carbon and hydrogen elements, and its oxygen index reaches 19.8, which makes epoxy resin an extremely flammable material, greatly limiting its application prospects. Therefore, flame retardants are generally added to improve the high temperature resistance of epoxy resin.

[0003] Boron nitride is a common additive, generally classified as hexagonal, cubic, and rhombohedral boron nitride. It exhibits high chemical stability, with hexagonal boron nitride offering excellent high-temperature resistance. However, due to its surface inertness and poor compatibility, it cannot be evenly dispersed when added to epoxy resin, forming a complete heat path and exhibiting limited flame retardant effects. Therefore, boron nitride modification is commonly used to improve its compatibility, but there is still room for further improvement.

[0004] Therefore, in order to continue to improve the flame retardancy and mechanical properties of epoxy resin, it is of great significance to improve the boron nitride modification method. Summary of the Invention

[0005] The object of the present invention is to provide a boron nitride modified flame retardant epoxy resin based copper clad laminate and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] The materials required for the flame-retardant epoxy resin-based copper clad laminate include, by mass: 45 to 55 parts of a composite flame retardant, 100 to 120 parts of an epoxy resin, 25 to 30 parts of a diluent, 4 to 6 parts of an epoxy cage-shaped polysilsesquioxane, and 30 to 40 parts of a curing agent.

[0008] More preferably, the materials required for the composite flame retardant include, by mass: 18 to 22 parts of modified boron nitride A and 27 to 33 parts of modified boron nitride B.

[0009] More preferably, the epoxy resin includes: bisphenol A epoxy resin.

[0010] More preferably, the materials required for the diluent include, by mass: 1 to 12 parts of alkylene glycidyl ether, 1 to 14 parts of phenyl glycidyl ether, and 1 to 11 parts of polypropylene glycol diglycidyl ether.

[0011] More preferably, the curing agent includes: tung oil anhydride.

[0012] More preferably, the boron nitride includes hexagonal boron nitride, and the particle size of the boron nitride is 600-800 mesh.

[0013] More preferably, the materials required for the modified boron nitride A include, by mass: 10 to 20 parts of boron nitride and 6.3 to 7.2 parts of myricetin.

[0014] Preferably, the materials required for the modified boron nitride B include, by mass: 15 to 30 parts of boron nitride, 8 to 10 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid), 1 to 2 parts of phosphorus pentoxide catalyst, and 8 to 10 parts of phosphoric acid.

[0015] More preferably, a method for preparing a boron nitride modified flame-retardant epoxy resin-based copper clad laminate comprises the following steps:

[0016] S1: Preparation of modified boron nitride A: Myricetin is dissolved in anhydrous ethanol, boron nitride is added, and after ultrasonic treatment, the upper liquid is centrifuged, filtered, washed, dried, and heat-treated to obtain modified boron nitride A;

[0017] S2: Preparation of modified boron nitride B: Boron nitride is added to an alkaline solution, heated to 80-90°C, ultrasonically treated, and centrifuged. The upper liquid is filtered, washed, and dried to obtain pretreated boron nitride; 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methylphosphonic acid) is added to a phosphoric acid solution, and then the pretreated boron nitride and the catalyst phosphorus pentoxide are added, heated, magnetically stirred, and reacted to obtain modified boron nitride B;

[0018] S3: Preparation of flame-retardant epoxy resin: Modified boron nitride A and modified boron nitride B are mixed in proportion to obtain a composite flame retardant; a diluent, epoxy cage-shaped polysilsesquioxane, composite flame retardant, and curing agent are added to the epoxy resin to obtain a flame-retardant epoxy resin;

[0019] S4: Preparation of flame-retardant epoxy resin-based copper clad laminate: evenly coat the flame-retardant epoxy resin on the ceramic fiber cloth, semi-cured, and then cover the copper foil on it, hot-press and cure to obtain the flame-retardant epoxy resin-based copper clad laminate.

[0020] Preferably, in step S1, the content of myricitrin in anhydrous ethanol is 70-80 mg / mL;

[0021] Preferably, in steps S1 and S2, during the ultrasonic process, the ultrasonic power is 200-250 W, and the ultrasonic time is 20-24 h; during the centrifugation process, the centrifugal speed is 3000-5000 rpm, and the centrifugation time is 5-10 min; the washing solution is anhydrous ethanol; during the drying process, the gas atmosphere is nitrogen, the drying temperature is 45-55°C, and the drying time is 8-12 h.

[0022] More preferably, during the heat treatment process, the heat treatment temperature is 200-220° C., and the heat treatment time is 5-7 hours.

[0023] The added myricetin has three benzene rings and a six-membered ring structure. It can produce a relatively strong π-π conjugation with the six-membered ring structure of hexagonal boron nitride, allowing the hexagonal boron nitride that is peeled off under ultrasound to tightly bind to myricetin. Moreover, due to its benzene ring structure, it can bind more boron nitride. At the same time, myricetin contains eight hydroxyl groups around it, which can greatly improve the chemical activity of the modified boron nitride after binding, allowing it to be more evenly dispersed and bound after being added to the epoxy resin system. However, considering that modified boron nitride is used as a flame retardant to increase the flame retardant properties of epoxy resin, it needs to be resistant to a certain high temperature. Myricetin has poor stability under high temperature conditions and can easily affect the resin curing process. Therefore, the myricetin-modified boron nitride is heat-treated in advance at conditions slightly above the epoxy resin curing temperature. This allows the more active hydroxyl groups in myricetin to be oxidized to ketone groups in advance, thereby improving its thermal stability at the curing temperature.

[0024] More preferably, in step S2, the alkaline solution is 30-40% NaOH.

[0025] Preferably, the content of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid) in the solution is 10-15 wt %; during the heating process: the heating temperature is 60-80° C., the heating time is 12-16 h, and the electromagnetic stirring speed is 70-80 rpm.

[0026] 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methylphosphonic acid) is a cyclic compound consisting of a twelve-membered ring with nitrogen atoms substituted at positions 1, 4, 7, and 10, each of which is linked to a methylphosphonic acid group. This structure allows it to undergo an esterification reaction with hydroxyl-modified boron nitride, allowing it to be modified on the surface of the boron nitride to produce modified boron nitride B. The remaining phosphonic acid groups can then be used to further bond to new modified boron nitrides, allowing for better dispersion and incorporation of modified boron nitride B into the epoxy resin during subsequent addition. The simultaneous introduction of nitrogen and phosphorus into the epoxy resin releases nitrogen gas during combustion, blocking oxygen and improving the material's flame retardancy. Phosphorus, upon high-temperature combustion, generates phosphoric acid or polyphosphoric acid, which is nonvolatile and promotes the formation of a dense char layer on the epoxy resin surface, insulating the material from heat and air, thus enhancing flame retardancy.

[0027] Wherein, in step S3, modified boron nitride A and modified boron nitride B are mixed to obtain a composite flame retardant, which can simultaneously improve the dispersibility and flame retardancy of the epoxy resin.

[0028] Preferably, because the introduction of a large amount of myricitrin into the modified boron nitride A contains a large number of benzene rings, which may increase the brittleness of the final epoxy resin and reduce the mechanical properties, the added modified boron nitride B has a cyclic heterocyclic structure, which can reduce the tensile stress inside the material and improve the toughness of the prepared epoxy resin.

[0029] More preferably, the addition interval in step S3 is 5 to 10 minutes.

[0030] Among them, the addition of epoxy cage-shaped polysilsesquioxane, on the one hand, is composed of a silicon-oxygen skeleton alternately connected by Si-O, and its bond energy is higher than that of CC bonds and CO bonds, which can significantly improve the thermal stability of epoxy resin. On the other hand, it can terminate the development of microcrack tips and induce silver streaks or shear bands or molecular chain rearrangement, thereby improving the toughness of epoxy resin.

[0031] More preferably, the epoxy resin coating thickness is 1 to 2 mm, and during the semi-curing process, the semi-curing temperature is 145 to 160° C., and the semi-curing time is 7 to 12 minutes.

[0032] More preferably, during the hot pressing and curing process, the curing temperature is 180-190° C., the curing pressure is 25-35 MPa, and the curing time is 3-4 hours.

[0033] Compared with the prior art, the beneficial effect achieved by the present invention is that a composite flame retardant prepared by combining heat-treated myricetin-modified boron nitride and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid)-modified boron nitride is added to an epoxy resin, so that the prepared epoxy resin has better flame retardancy and toughness, and also the prepared epoxy resin-based copper clad laminate has better flame retardant effect. DETAILED DESCRIPTION

[0034] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments 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 any creative efforts are within the scope of protection of the present invention.

[0035] In this embodiment, it should be noted that the purchase manufacturers of all raw materials involved in the present invention are not subject to any special restrictions, and illustratively include: bimodal A-type epoxy resin, purity 99%, provided by Jinan Chuangshi Chemical Co., Ltd.; boron nitride, purity 99.5%, provided by Henan Yejiu Sheng Industrial Co., Ltd.; myricetin, purity 99%, provided by Hubei Yongkuo Technology Co., Ltd.; 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methylphosphonic acid), purity 99%, provided by Wuhan Xinxin Jiali Biotechnology Co., Ltd.; tung oil anhydride, purity 99%, provided by Shandong Jiaying Chemical Technology Co., Ltd.; glycidyl 12-14 alkyl ether, purity 99%, provided by Hubei Wande Chemical Co., Ltd.; polypropylene glycol diglycidyl ether, purity 99%, provided by Chongqing Ruiya Biotechnology Co., Ltd.; phenyl glycidyl ether, purity 99%, provided by Changzhou Hongyu Chemical Co., Ltd.

[0036] In the embodiment, the materials required for the diluent include, by mass: 6 parts of alkylene glycidyl ether, 7 parts of phenyl glycidyl ether, and 5 parts of polypropylene glycol diglycidyl ether.

[0037] Example 1

[0038] The materials required for the flame-retardant epoxy resin-based copper clad laminate include, by mass: 50 parts of composite flame retardant, 110 parts of bisphenol A epoxy resin, 28 parts of diluent, 5 parts of epoxy cage polysilsesquioxane, and 35 parts of tung oil anhydride.

[0039] The materials required for the composite flame retardant include, by mass: 20 parts of modified boron nitride A and 30 parts of modified boron nitride B.

[0040] The materials required for modified boron nitride A include, by mass: 15 parts of boron nitride and 6.7 parts of myricetin.

[0041] The materials required for modified boron nitride B include, by mass: 25 parts of boron nitride, 9 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid), 1 part of phosphorus pentoxide, and 9 parts of phosphoric acid.

[0042] S1: Preparation of modified boron nitride A: 6.7 parts of myricetin were dissolved in anhydrous ethanol to a concentration of 75 mg / mL, and then 15 parts of boron nitride were added. The mixture was ultrasonically treated at a power of 200 W for 22 hours. The supernatant was centrifuged at 4000 rpm for 5 minutes. The mixture was then filtered, washed with anhydrous ethanol, and dried at 50°C under a nitrogen atmosphere for 10 hours. Finally, the mixture was heat-treated at 200°C for 10 hours to obtain modified boron nitride A.

[0043] S2: Preparation of modified boron nitride B: 25 parts of boron nitride were added to 35% NaOH, heated to 85°C, and ultrasonicated at an ultrasonic power of 200 W for 22 hours; the upper liquid was centrifuged at a speed of 4000 rpm for 5 minutes; then filtered, washed with anhydrous ethanol, and dried at 50°C under a nitrogen atmosphere for 10 hours to obtain pretreated boron nitride; 9 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methylphosphonic acid) were added to a phosphoric acid solution so that its content in the solution was 10wt%, pretreated boron nitride and 1 part of phosphorus pentoxide catalyst were added, and the mixture was heated at 70°C for 14 hours while magnetically stirred at a speed of 75 rpm. The modified boron nitride B was obtained by filtering, washing, and drying in the same process as the above steps;

[0044] S3: Preparation of flame-retardant epoxy resin: 20 parts of modified boron nitride A and 30 parts of modified boron nitride B were mixed to obtain a composite flame retardant; 25 parts of diluent, 5 parts of epoxy cage-shaped polysilsesquioxane, 50 parts of composite flame retardant, and 35 parts of tung oil anhydride were added to 110 parts of bisphenol A epoxy resin, respectively, while stirring during the addition process, with an interval of ten minutes between each addition, to obtain a flame-retardant epoxy resin;

[0045] S4: Preparation of flame-retardant epoxy resin-based copper clad laminate: Flame-retardant epoxy resin is evenly coated on ceramic fiber cloth with a coating thickness of 1 mm; then semi-cured at 150°C for 10 minutes; then copper foil is covered on top, and hot pressed and cured at a temperature of 185°C and a pressure of 30 MPa for 4 hours to obtain a flame-retardant epoxy resin-based copper clad laminate.

[0046] Example 2

[0047] The materials required for the flame-retardant epoxy resin-based copper clad laminate include, by mass: 45 parts of composite flame retardant, 100 parts of bisphenol A epoxy resin, 25 parts of diluent, 4 parts of epoxy cage-shaped polysilsesquioxane, and 30 parts of tung oil anhydride.

[0048] The materials required for the composite flame retardant include, by mass: 18 parts of modified boron nitride A and 27 parts of modified boron nitride B.

[0049] The materials required for modified boron nitride A include, by mass: 10 parts of boron nitride and 6.3 parts of myricetin.

[0050] The materials required for modified boron nitride B include, by mass: 15 parts of boron nitride, 8 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid), 1 part of phosphorus pentoxide, and 8 parts of phosphoric acid.

[0051] S1: Preparation of modified boron nitride A: 6.3 parts of myricetin were dissolved in anhydrous ethanol to a concentration of 70 mg / mL, and then 10 parts of boron nitride were added. The mixture was ultrasonically treated at an ultrasonic power of 200 for 20 hours. The supernatant was centrifuged at 3000 rpm for 5 minutes. The mixture was then filtered, washed with anhydrous ethanol, and dried at 45°C under a nitrogen atmosphere for 8 hours. The mixture was then heat treated at 200°C for 8 hours to obtain modified boron nitride A.

[0052] S2: Preparation of modified boron nitride B: 15 parts of boron nitride were added to 30% NaOH, heated to 80°C, and ultrasonicated at an ultrasonic power of 200 for 20 hours; the upper liquid was centrifuged at a speed of 3000 rpm for 5 minutes; then filtered, washed with anhydrous ethanol, and dried at 45°C under a nitrogen atmosphere for 8 hours to obtain pretreated boron nitride; 8 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methylphosphonic acid) were added to a phosphoric acid solution so that its content in the solution was 10wt%, pretreated boron nitride and 1 part of phosphorus pentoxide catalyst were added, and the mixture was heated at 60°C for 12 hours while magnetically stirred at a speed of 70 rpm. The modified boron nitride B was obtained by filtering, washing, and drying in the same process as the above steps;

[0053] S3: Preparation of flame-retardant epoxy resin: 18 parts of modified boron nitride A and 27 parts of modified boron nitride B were mixed to obtain a composite flame retardant; 25 parts of diluent, 4 parts of epoxy cage-shaped polysilsesquioxane, 45 parts of composite flame retardant, and 30 parts of tung oil anhydride were added to 100 parts of bisphenol A epoxy resin, respectively, with stirring during the addition process, with each addition taking ten minutes to obtain a flame-retardant epoxy resin;

[0054] S4: Preparation of flame-retardant epoxy resin-based copper clad laminate: The flame-retardant epoxy resin is evenly coated on the ceramic fiber cloth with a coating thickness of 1 mm; then semi-cured at 145°C for 7 minutes; then copper foil is covered on it, and hot pressed and cured at a temperature of 180°C and a pressure of 25 MPa for 3 hours to obtain a flame-retardant epoxy resin-based copper clad laminate.

[0055] Example 3

[0056] The materials required for the flame-retardant epoxy resin-based copper clad laminate include, by mass: 55 parts of composite flame retardant, 120 parts of bisphenol A epoxy resin, 30 parts of diluent, 6 parts of epoxy cage-shaped polysilsesquioxane, and 40 parts of tung oil anhydride.

[0057] The materials required for the composite flame retardant include, by mass: 22 parts of modified boron nitride A and 33 parts of modified boron nitride B.

[0058] The materials required for modified boron nitride A include, by mass: 20 parts of boron nitride and 7.2 parts of myricetin.

[0059] The materials required for modified boron nitride B include, by mass: 30 parts of boron nitride, 10 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid), 2 parts of phosphorus pentoxide, and 10 parts of phosphoric acid.

[0060] S1: Preparation of modified boron nitride A: 7.2 parts of myricetin were dissolved in anhydrous ethanol to a concentration of 80 mg / mL, and then 20 parts of boron nitride were added. The mixture was ultrasonically treated at 250 W for 24 hours. The supernatant was centrifuged at 5000 rpm for 10 minutes. The mixture was then filtered, washed with anhydrous ethanol, and dried at 55°C under a nitrogen atmosphere for 12 hours. Finally, the mixture was heat-treated at 220°C for 12 hours to obtain modified boron nitride A.

[0061] S2: Preparation of modified boron nitride B: 30 parts of boron nitride were added to 40% NaOH, heated to 90°C, and ultrasonicated at an ultrasonic power of 250W for 24 hours; the upper liquid was centrifuged at a speed of 5000 rpm for 10 minutes; then filtered, washed with anhydrous ethanol, and dried at 55°C under a nitrogen atmosphere for 12 hours to obtain pretreated boron nitride; 10 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methylphosphonic acid) were added to a phosphoric acid solution so that its content in the solution was 15wt%, pretreated boron nitride and 2 parts of phosphorus pentoxide catalyst were added, and the mixture was heated at 80°C for 16 hours while magnetically stirred at a speed of 80 rpm. The modified boron nitride B was obtained by filtering, washing, and drying in the same process as the above steps;

[0062] S3: Preparation of flame-retardant epoxy resin: 2 parts of modified boron nitride A and 33 parts of modified boron nitride B were mixed to obtain a composite flame retardant; 30 parts of diluent, 6 parts of epoxy cage-shaped polysilsesquioxane, 55 parts of composite flame retardant, and 40 parts of tung oil anhydride were added to 120 parts of bisphenol A epoxy resin, respectively, while stirring during the addition process, with an interval of ten minutes between each addition, to obtain a flame-retardant epoxy resin;

[0063] S4: Preparation of flame-retardant epoxy resin-based copper clad laminate: Flame-retardant epoxy resin is evenly coated on ceramic fiber cloth with a coating thickness of 1.5 mm; then semi-cured at 160°C for 12 minutes; then copper foil is covered on top, and hot pressed and cured at a temperature of 190°C and a pressure of 35 MPa for 4 hours to obtain a flame-retardant epoxy resin-based copper clad laminate.

[0064] Comparative Example 1: Based on Example 1, the amount of myricetin added was reduced, specifically comprising the following steps:

[0065] The materials required for the flame-retardant epoxy resin-based copper clad laminate include, by mass: 50 parts of composite flame retardant, 110 parts of bisphenol A epoxy resin, 28 parts of diluent, 5 parts of epoxy cage polysilsesquioxane, and 35 parts of tung oil anhydride.

[0066] The materials required for the composite flame retardant include, by mass: 20 parts of modified boron nitride A and 30 parts of modified boron nitride B.

[0067] The materials required for modified boron nitride A include, by mass: 15 parts of boron nitride and 0.5 parts of myricetin.

[0068] The materials required for modified boron nitride B include, by mass: 25 parts of boron nitride, 9 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid), 1 part of phosphorus pentoxide, and 9 parts of phosphoric acid.

[0069] S1: Preparation of modified boron nitride A: 0.5 parts of myricetin was dissolved in anhydrous ethanol to a concentration of 6 mg / mL, and then 15 parts of boron nitride was added. The mixture was ultrasonically treated at a power of 200 W for 22 hours. The supernatant was centrifuged at 4000 rpm for 5 minutes. The mixture was then filtered, washed with anhydrous ethanol, and dried at 50°C under a nitrogen atmosphere for 10 hours. Finally, the mixture was heat-treated at 200°C for 10 hours to obtain modified boron nitride A.

[0070] S2: Preparation of modified boron nitride B: 25 parts of boron nitride were added to 35% NaOH, heated to 85°C, and ultrasonicated at an ultrasonic power of 200 W for 22 hours; the upper liquid was centrifuged at a speed of 4000 rpm for 5 minutes; then filtered, washed with anhydrous ethanol, and dried at 50°C under a nitrogen atmosphere for 10 hours to obtain pretreated boron nitride; 9 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methylphosphonic acid) were added to a phosphoric acid solution so that its content in the solution was 10wt%, pretreated boron nitride and 1 part of phosphorus pentoxide catalyst were added, and the mixture was heated at 70°C for 14 hours while magnetically stirred at a speed of 75 rpm. The modified boron nitride B was obtained by filtering, washing, and drying in the same process as the above steps;

[0071] S3: Preparation of flame-retardant epoxy resin: 20 parts of modified boron nitride A and 30 parts of modified boron nitride B were mixed to obtain a composite flame retardant; 25 parts of diluent, 5 parts of epoxy cage-shaped polysilsesquioxane, 50 parts of composite flame retardant, and 35 parts of tung oil anhydride were added to 110 parts of bisphenol A epoxy resin, respectively, while stirring during the addition process, with an interval of ten minutes between each addition, to obtain a flame-retardant epoxy resin;

[0072] S4: Preparation of flame-retardant epoxy resin-based copper clad laminate: Flame-retardant epoxy resin is evenly coated on ceramic fiber cloth with a coating thickness of 1 mm; then semi-cured at 150°C for 10 minutes; then copper foil is covered on top, and hot pressed and cured at a temperature of 185°C and a pressure of 30 MPa for 4 hours to obtain a flame-retardant epoxy resin-based copper clad laminate.

[0073] Comparative Example 2: Based on Comparative Example 1, the contents of modified boron nitride A and modified boron nitride B were exchanged, specifically comprising the following steps:

[0074] The materials required for the flame-retardant epoxy resin-based copper clad laminate include, by mass: 50 parts of composite flame retardant, 110 parts of bisphenol A epoxy resin, 28 parts of diluent, 5 parts of epoxy cage polysilsesquioxane, and 35 parts of tung oil anhydride.

[0075] The materials required for the composite flame retardant include, by mass: 30 parts of modified boron nitride A and 20 parts of modified boron nitride B.

[0076] The materials required for modified boron nitride A include, by mass: 15 parts of boron nitride and 6.7 parts of myricetin.

[0077] The materials required for modified boron nitride B include, by mass: 25 parts of boron nitride, 9 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid), 1 part of phosphorus pentoxide, and 9 parts of phosphoric acid.

[0078] S1: Preparation of modified boron nitride A: 6.7 parts of myricetin were dissolved in anhydrous ethanol to a concentration of 75 mg / mL, and then 15 parts of boron nitride were added. The mixture was ultrasonically treated at a power of 200 W for 22 hours. The supernatant was centrifuged at 4000 rpm for 5 minutes. The mixture was then filtered, washed with anhydrous ethanol, and dried at 50°C under a nitrogen atmosphere for 10 hours. Finally, the mixture was heat-treated at 200°C for 10 hours to obtain modified boron nitride A.

[0079] S2: Preparation of modified boron nitride B: 25 parts of boron nitride were added to 35% NaOH, heated to 85°C, and ultrasonicated at an ultrasonic power of 200 W for 22 hours; the upper liquid was centrifuged at a speed of 4000 rpm for 5 minutes; then filtered, washed with anhydrous ethanol, and dried at 50°C under a nitrogen atmosphere for 10 hours to obtain pretreated boron nitride; 9 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methylphosphonic acid) were added to a phosphoric acid solution so that its content in the solution was 10wt%, pretreated boron nitride and 1 part of phosphorus pentoxide catalyst were added, and the mixture was heated at 70°C for 14 hours while magnetically stirred at a speed of 75 rpm. The modified boron nitride B was obtained by filtering, washing, and drying in the same process as the above steps;

[0080] S3: Preparation of flame-retardant epoxy resin: 30 parts of modified boron nitride A and 20 parts of modified boron nitride B were mixed to obtain a composite flame retardant; 25 parts of diluent, 5 parts of epoxy cage-shaped polysilsesquioxane, 50 parts of composite flame retardant, and 35 parts of tung oil anhydride were added to 110 parts of bisphenol A epoxy resin, respectively, while stirring during the addition process, with an interval of ten minutes between each addition, to obtain a flame-retardant epoxy resin;

[0081] S4: Preparation of flame-retardant epoxy resin-based copper clad laminate: Flame-retardant epoxy resin is evenly coated on ceramic fiber cloth with a coating thickness of 1 mm; then semi-cured at 150°C for 10 minutes; then copper foil is covered on top, and hot pressed and cured at a temperature of 185°C and a pressure of 30 MPa for 4 hours to obtain a flame-retardant epoxy resin-based copper clad laminate.

[0082] Comparative Example 3: Based on Comparative Example 1, the amount of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid) added was reduced, specifically comprising the following steps:

[0083] The materials required for the flame-retardant epoxy resin-based copper clad laminate include, by mass: 50 parts of composite flame retardant, 110 parts of bisphenol A epoxy resin, 28 parts of diluent, 5 parts of epoxy cage polysilsesquioxane, and 35 parts of tung oil anhydride.

[0084] The materials required for the composite flame retardant include, by mass: 20 parts of modified boron nitride A and 30 parts of modified boron nitride B.

[0085] The materials required for modified boron nitride A include, by mass: 15 parts of boron nitride and 6.7 parts of myricetin.

[0086] The materials required for modified boron nitride B include, by mass: 25 parts of boron nitride, 0.5 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid), 1 part of phosphorus pentoxide, and 9 parts of phosphoric acid.

[0087] S1: Preparation of modified boron nitride A: 6.7 parts of myricetin were dissolved in anhydrous ethanol to a concentration of 75 mg / mL, and then 15 parts of boron nitride were added. The mixture was ultrasonically treated at a power of 200 W for 22 hours. The supernatant was centrifuged at 4000 rpm for 5 minutes. The mixture was then filtered, washed with anhydrous ethanol, and dried at 50°C under a nitrogen atmosphere for 10 hours. Finally, the mixture was heat-treated at 200°C for 10 hours to obtain modified boron nitride A.

[0088] S2: Preparation of modified boron nitride B: 25 parts of boron nitride were added to 35% NaOH, heated to 85°C, and ultrasonicated at an ultrasonic power of 200 W for 22 hours; the upper liquid was centrifuged at a speed of 4000 rpm for 5 minutes; then filtered, washed with anhydrous ethanol, and dried at 50°C under a nitrogen atmosphere for 10 hours to obtain pretreated boron nitride; 0.5 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methylphosphonic acid) were added to a phosphoric acid solution so that its content in the solution was 0.5wt%, pretreated boron nitride and 1 part of phosphorus pentoxide catalyst were added, and the mixture was heated at 70°C for 14 hours while magnetically stirred at a speed of 75 rpm. The modified boron nitride B was obtained by filtering, washing, and drying in the same process as the above steps;

[0089] S3: Preparation of flame-retardant epoxy resin: 20 parts of modified boron nitride A and 30 parts of modified boron nitride B were mixed to obtain a composite flame retardant; 25 parts of diluent, 5 parts of epoxy cage-shaped polysilsesquioxane, 50 parts of composite flame retardant, and 35 parts of tung oil anhydride were added to 110 parts of bisphenol A epoxy resin, respectively, while stirring during the addition process, with an interval of ten minutes between each addition, to obtain a flame-retardant epoxy resin;

[0090] S4: Preparation of flame-retardant epoxy resin-based copper clad laminate: Flame-retardant epoxy resin is evenly coated on ceramic fiber cloth with a coating thickness of 1 mm; then semi-cured at 150°C for 10 minutes; then copper foil is covered on top, and hot pressed and cured at a temperature of 185°C and a pressure of 30 MPa for 4 hours to obtain a flame-retardant epoxy resin-based copper clad laminate.

[0091] Comparative Example 4: Based on Example 1, without adding epoxy cage-type polysilsesquioxane, the specific scheme includes the following steps:

[0092] The materials required for the flame-retardant epoxy resin-based copper clad laminate include, by mass: 50 parts of composite flame retardant, 115 parts of bisphenol A epoxy resin, 28 parts of diluent, and 35 parts of tung oil anhydride.

[0093] The materials required for the composite flame retardant include, by mass: 20 parts of modified boron nitride A and 30 parts of modified boron nitride B.

[0094] The materials required for modified boron nitride A include, by mass: 15 parts of boron nitride and 6.7 parts of myricetin.

[0095] The materials required for modified boron nitride B include, by mass: 25 parts of boron nitride, 9 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid), 1 part of phosphorus pentoxide, and 9 parts of phosphoric acid.

[0096] S1: Preparation of modified boron nitride A: 6.7 parts of myricetin were dissolved in anhydrous ethanol to a concentration of 75 mg / mL, and then 15 parts of boron nitride were added. The mixture was ultrasonically treated at a power of 200 W for 22 hours. The supernatant was centrifuged at 4000 rpm for 5 minutes. The mixture was then filtered, washed with anhydrous ethanol, and dried at 50°C under a nitrogen atmosphere for 10 hours. Finally, the mixture was heat-treated at 200°C for 10 hours to obtain modified boron nitride A.

[0097] S2: Preparation of modified boron nitride B: 25 parts of boron nitride were added to 35% NaOH, heated to 85°C, and ultrasonicated at an ultrasonic power of 200 W for 22 hours; the upper liquid was centrifuged at a speed of 4000 rpm for 5 minutes; then filtered, washed with anhydrous ethanol, and dried at 50°C under a nitrogen atmosphere for 10 hours to obtain pretreated boron nitride; 9 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methylphosphonic acid) were added to a phosphoric acid solution so that its content in the solution was 10wt%, pretreated boron nitride and 1 part of phosphorus pentoxide catalyst were added, and the mixture was heated at 70°C for 14 hours while magnetically stirred at a speed of 75 rpm. The modified boron nitride B was obtained by filtering, washing, and drying in the same process as the above steps;

[0098] S3: Preparation of flame-retardant epoxy resin: 20 parts of modified boron nitride A and 30 parts of modified boron nitride B were mixed to obtain a composite flame retardant; 25 parts of diluent, 50 parts of composite flame retardant, and 35 parts of tung oil anhydride were added to 115 parts of bisphenol A epoxy resin, respectively, while stirring during the addition process, with an interval of ten minutes between each addition, to obtain a flame-retardant epoxy resin;

[0099] S4: Preparation of flame-retardant epoxy resin-based copper clad laminate: Flame-retardant epoxy resin is evenly coated on ceramic fiber cloth with a coating thickness of 1 mm; then semi-cured at 150°C for 10 minutes; then copper foil is covered on top, and hot pressed and cured at a temperature of 185°C and a pressure of 30 MPa for 4 hours to obtain a flame-retardant epoxy resin-based copper clad laminate.

[0100] Detection experiment 1:

[0101] The flame retardant epoxy resin-based material was tested for tensile strength using a universal tensile testing machine. The test data are shown in Table 1.

[0102] Detection experiment 2:

[0103] The thermal conductivity of the flame retardant epoxy resin-based material was tested using a steady-state thermal conductivity analyzer. The test data are shown in Table 1.

[0104] Table 1

[0105] project Tensile strength / Mpa <![CDATA[Thermal conductivity / W·m -1 ·K -1 > Example 1 89.25 0.85 Example 2 87.44 0.78 Example 3 88.90 0.76 Comparative Example 1 78.42 0.65 Comparative Example 2 70.64 0.71 Comparative Example 3 69.81 0.64 Comparative Example 4 82.78 0.72

[0106] Comparative Example 1: Based on Example 1, the amount of myricetin added was reduced, so that the amount of boron nitride obtained by modifying myricetin was reduced, and it could not be well dispersed in the epoxy resin, resulting in a decrease in flame retardancy and mechanical properties.

[0107] Comparative Example 2: Based on Comparative Example 1, the contents of modified boron nitride A and modified boron nitride B were exchanged. Due to the increase in the content of modified boron nitride A, the benzene ring content in the epoxy resin increased. At the same time, there was not enough modified boron nitride B to improve its toughness, which reduced the mechanical properties of the prepared epoxy resin.

[0108] Comparative Example 3: Based on Comparative Example 1, the amount of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid) added was reduced, so that the effective modification amount in the modified boron nitride B was reduced, resulting in a decrease in the flame retardant properties of the epoxy resin, and it was not enough to compensate for the decrease in toughness caused by the excessive benzene rings in the modified boron nitride A.

[0109] Comparative Example 4: Based on Example 1, without adding epoxy cage-type polysilsesquioxane, the flame retardant properties and mechanical properties of the prepared epoxy resin were reduced.

[0110] Conclusion: By adding myricitrin-modified boron nitride A and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methylphosphonic acid)-modified boron nitride B, as well as epoxy cage-type polysilsesquioxane, the flame retardancy and mechanical properties of epoxy resin were improved, and a boron nitride-modified flame-retardant epoxy resin-based copper clad laminate was successfully prepared.

[0111] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A flame-retardant epoxy resin-based copper-clad laminate modified with boron nitride, characterized in that: The materials of the flame-retardant epoxy resin-based copper clad laminate include, by mass, 45 to 55 parts of a composite flame retardant, 100 to 120 parts of an epoxy resin, 25 to 30 parts of a diluent, 4 to 6 parts of an epoxy cage-shaped polysilsesquioxane, and 30 to 40 parts of a curing agent.

2. The boron nitride modified flame-retardant epoxy resin-based copper clad laminate according to claim 1, characterized in that: The materials of the composite flame retardant include, by mass: 18 to 22 parts of modified boron nitride A and 27 to 33 parts of modified boron nitride B.

3. The boron nitride modified flame-retardant epoxy resin-based copper clad laminate according to claim 1, characterized in that: The epoxy resin includes bisphenol A epoxy resin; the curing agent includes tung oil anhydride.

4. The boron nitride modified flame-retardant epoxy resin-based copper clad laminate according to claim 1, characterized in that: The materials of the diluent include, by mass: 1 to 12 parts of alkylene glycidyl ether, 1 to 14 parts of phenyl glycidyl ether, and 1 to 11 parts of polypropylene glycol diglycidyl ether.

5. The boron nitride modified flame-retardant epoxy resin-based copper clad laminate according to claim 1, characterized in that: The materials of the modified boron nitride A include, by mass: 10 to 20 parts of boron nitride and 6.3 to 7.2 parts of myricetin.

6. The boron nitride modified flame-retardant epoxy resin-based copper clad laminate according to claim 1, characterized in that: The materials of the modified boron nitride B include, by mass: 15 to 30 parts of boron nitride, 8 to 10 parts of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid), 1 to 2 parts of phosphorus pentoxide, and 8 to 10 parts of phosphoric acid.

7. A method for preparing a flame-retardant epoxy resin-based copper-clad laminate modified with boron nitride, characterized in that: The following steps are involved: S1: Preparation of modified boron nitride A: Myricetin is dissolved in anhydrous ethanol, boron nitride is added, and after ultrasonic treatment, the upper liquid is centrifuged, filtered, washed, dried, and heat-treated to obtain modified boron nitride A; S2: Preparation of modified boron nitride B: Boron nitride is added to an alkaline solution, heated to 80-90°C, ultrasonically treated, and centrifuged. The upper liquid is filtered, washed, and dried to obtain pretreated boron nitride; 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methylphosphonic acid) is added to a phosphoric acid solution, and then the pretreated boron nitride and the catalyst phosphorus pentoxide are added, heated, magnetically stirred, and reacted to obtain modified boron nitride B; S3: Preparation of flame-retardant epoxy resin: Modified boron nitride A and modified boron nitride B are mixed in proportion to obtain a composite flame retardant; a diluent, epoxy cage-shaped polysilsesquioxane, composite flame retardant, and curing agent are added to the epoxy resin to obtain a flame-retardant epoxy resin; S4: Preparation of flame-retardant epoxy resin-based copper clad laminate: evenly coat the flame-retardant epoxy resin on the ceramic fiber cloth, semi-cured, and then cover the copper foil on it, hot-press and cure to obtain the flame-retardant epoxy resin-based copper clad laminate.

8. The method for preparing a boron nitride modified flame-retardant epoxy resin-based copper clad laminate according to claim 7, wherein: During the heat treatment process, the heat treatment temperature is 200-220° C., and the heat treatment time is 5-7 hours.

9. The method for preparing a flame-retardant epoxy resin-based copper clad laminate modified with boron nitride according to claim 7, wherein: In the heating process of step S2, the heating temperature is 60-80° C. and the heating time is 12-16 hours.