Flame-retardant toughened epoxy resin copper-clad plate and preparation method thereof

Abstract

According to the flame-retardant toughened epoxy resin copper-clad plate and the preparation method thereof, epoxidized lignin is added during synthesis of epoxy resin, so that the mechanical property of the epoxy resin can be effectively improved, the toughness of an epoxy resin-based material is further ensured, and a composite LDH flame-retardant material is added into the epoxy resin-based material, so that the flame-retardant toughened epoxy resin copper-clad plate is prepared. The flame retardant property of the epoxy resin material can be effectively improved, meanwhile, the mechanical property of the epoxy resin material after LDH is added is guaranteed, and the flame retardant property and the toughening effect of the epoxy resin material are guaranteed when the epoxy resin material is applied to a copper-clad plate; the mechanical property of an epoxy resin system is modified by epoxidized lignin under the synergistic dispersion effect of polyethylene glycol, so that the toughness of the epoxy resin copper-clad plate is ensured; mgAl-LDH in the flame retardant is compounded with hydroxyl functionalized carbon nanotubes, and the compound is used as a uniform mechanical support skeleton; the nano copper molybdate particles are uniformly loaded outside the supporting framework, so that the flame retardant property of the epoxy resin material can be effectively enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of copper clad laminates, and more specifically, to a flame-retardant toughened epoxy resin copper clad laminate and a preparation method thereof. Background Art

[0002] The quality, performance, manufacturing cost, manufacturability, manufacturing level, long-term reliability, and stability in the manufacture of printed circuit boards mainly depend on copper clad laminates. Epoxy resin has been widely used in electrical equipment insulation and microelectronic equipment encapsulation due to its excellent adhesion, corrosion resistance, good dielectric properties, and preparability. However, when epoxy resin is applied to copper clad laminates, its flame retardancy is a very important index and needs to be modified and improved.

[0003] Layered double hydroxide (LDH) is a hydroxide with a hydrotalcite-like layered structure, containing two or more metal cations; LDH is prone to endothermic decomposition, which has a cooling effect on the fire field. The generated water vapor can dilute the combustible gas mixture, and the generated metal oxide can be used as an insulating covering to inhibit the heat radiation from the heat source and the diffusion and replenishment of oxygen in the environment to the polymer on the surface of the polymer substrate, while inhibiting the release of toxic smoke during the heating process of the polymer. Thanks to the above "cooling effect" and "asphyxiation effect" and the non-toxic and harmless nature superior to phosphorus-based, halogen-based, and organic flame retardants, LDH has received attention in recent years as a new type of clean, low-toxic, and economical inorganic flame retardant.

[0004] However, the compatibility between inorganic LDH and organic epoxy resin substrates is poor and its flame retardancy efficiency still needs to be improved, resulting in the need for a large addition amount of LDH. Usually, adding inorganic flame retardants to pure epoxy resin will damage its mechanical properties, limiting the flame retardant applications of epoxy resin and inorganic LDH. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a flame-retardant toughened epoxy resin copper clad laminate and a preparation method thereof.

[0006] A flame-retardant toughened epoxy resin copper clad laminate includes an electronic glass fiber cloth, a copper foil, and an impregnating material; the raw materials of the impregnating material are calculated by weight percentage as: 4.4 - 4.8% of epoxidized lignin, 14.0 - 15.0% of polyethylene glycol, 19.2 - 21.2% of polyetheramine, 2.9 - 3.1% of a flame retardant, and the rest is bisphenol A diglycidyl ether.

[0007] Further, the polyethylene glycol is one or a combination of PEG-200, PEG-400, and PEG-600.

[0008] Further, the raw materials of the flame retardant are calculated by weight percentage as follows: 11.1 - 11.9% of aluminum chloride hexahydrate, 4.6 - 5.4% of nano copper molybdate, 22.1 - 22.9% of magnesium chloride hexahydrate, 0.95 - 1.15% of hydroxyl-functionalized carbon nanotubes, 14.1 - 14.9% of sodium hydroxide, and the rest is urea.

[0009] Further, the raw materials of the impregnating material are calculated by weight percentage as follows: 4.5 - 4.7% of epoxidized lignin, 14.3 - 14.7% of polyethylene glycol, 19.7 - 20.7% of polyetheramine, 2.95 - 3.05% of the flame retardant, and the rest is bisphenol A diglycidyl ether; the raw materials of the flame retardant are calculated by weight percentage as follows: 11.4 - 11.6% of aluminum chloride hexahydrate, 4.3 - 5.1% of nano copper molybdate, 22.4 - 22.6% of magnesium chloride hexahydrate, 1.02 - 1.08% of hydroxyl-functionalized carbon nanotubes, 14.4 - 14.6% of sodium hydroxide, and the rest is urea.

[0010] Further, the raw materials of the impregnating material are calculated by weight percentage as follows: 4.6% of epoxidized lignin, 14.5% of polyethylene glycol, 20.2% of polyetheramine, 3.0% of the flame retardant, and the rest is bisphenol A diglycidyl ether; the raw materials of the flame retardant are calculated by weight percentage as follows: 11.5% of aluminum chloride hexahydrate, 5.0% of nano copper molybdate, 22.5% of magnesium chloride hexahydrate, 1.05% of hydroxyl-functionalized carbon nanotubes, 14.5% of sodium hydroxide, and the rest is urea.

[0011] A preparation method of a flame-retardant and toughened epoxy resin copper clad laminate is as follows:

[0012] Step 1: Weigh epoxidized lignin, polyethylene glycol, polyetheramine, bisphenol A diglycidyl ether in the raw materials of the impregnating material, and aluminum chloride hexahydrate, nano copper molybdate, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes, sodium hydroxide, urea in the raw materials of the flame retardant.

[0013] Step 2: Add aluminum chloride hexahydrate, nano copper molybdate, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes and urea in Step 1 into deionized water, perform ultrasonic treatment for 20 - 40 minutes, add sodium hydroxide, then perform ultrasonic treatment for 5 - 10 minutes, carry out magnetic stirring and heating reaction treatment for 3 - 4 hours, cool to room temperature, perform centrifugal washing treatment until the pH of the centrifugal supernatant is 7.0, filter by suction to obtain the product and then perform drying treatment to obtain the flame retardant.

[0014] Step 3: Add the epoxidized lignin in Step 1 and the flame retardant in Step 2 into the polyethylene glycol in Step 1, perform ultrasonic treatment for 10 - 20 minutes to obtain a modified mixture.

[0015] Step 4: Add the polyetheramine and bisphenol A diglycidyl ether in Step 1 into the modified mixture in Step 3, and stir for 0.5 - 1.5 hours to obtain an impregnating material;

[0016] Step 5: Immerse the electronic glass fiber cloth in the impregnating material prepared in Step 4 for 25 - 30 min, cure for 5.0 - 6.0 h, and cool to room temperature after curing to obtain an epoxy resin-based semi-cured sheet;

[0017] Step 6: Place a copper foil on each of the upper and lower surfaces of the epoxy resin-based semi-cured sheet, and then send it into a hot press for hot pressing. After hot pressing, a flame-retardant and toughened epoxy resin copper clad laminate is obtained.

[0018] Further, in Step 2, the weight ratio of the total weight of aluminum chloride hexahydrate, copper molybdate nanometer, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes, and urea to the weight of deionized water is 1:14 - 20, the ultrasonic frequency is 1.4 - 1.6 MHz, the ultrasonic power is 160 - 240 W, the magnetic stirring speed is 500 - 700 r / min, the heating temperature is 100 °C, the water liquid is subjected to condensation reflux treatment during heating, washing treatment is carried out with deionized water, and the centrifugation speed is 6000 - 8000 r / min.

[0019] Further, in Step 3, the ultrasonic frequency is 1.4 - 1.6 MHz, the ultrasonic power is 160 - 240 W; in Step 4, the stirring speed is 550 - 750 r / min; in Step 5, the curing process is: first cure at 80 - 90 °C for 3 - 4 hours, and then cure at 120 - 140 °C for 2 - 3 hours; in Step 6, the hot press is set with a hot pressing temperature of 230 - 240 °C, a pressure of 85 - 90 kg / cm 2 , and the pressing time is 18 - 19 h.

[0020] Further, in Step 2, the weight ratio of the total weight of aluminum chloride hexahydrate, copper molybdate nanometer, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes, and urea to the weight of deionized water is 1:16 - 18, the ultrasonic frequency is 1.45 - 1.55 MHz, the ultrasonic power is 190 - 210 W, the magnetic stirring speed is 560 - 640 r / min, the heating temperature is 100 °C, the water liquid is subjected to condensation reflux treatment during heating, washing treatment is carried out with deionized water, and the centrifugation speed is 6500 - 7500 r / min; in Step 3, the ultrasonic frequency is 1.45 - 1.55 MHz, the ultrasonic power is 190 - 210 W; in Step 4, the stirring speed is 600 - 700 r / min; in Step 5, the curing process is: first cure at 82 - 88 °C for 3 - 4 hours, and then cure at 125 - 135 °C for 2 - 3 hours; in Step 6, the hot press is set with a hot pressing temperature of 233 - 237 °C, a pressure of 85 - 90 kg / cm 2, the lamination time is 18 - 19 h.

[0021] Further, in Step 2, the weight ratio of the total weight of aluminum chloride hexahydrate, copper molybdate nanometer, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes and urea to the weight of deionized water is 1:17, the ultrasonic frequency is 1.5 MHz, the ultrasonic power is 200 W, the magnetic stirring speed is 600 r / min, the heating temperature is 100 °C, during the heating process, the water solution is subjected to condensation reflux treatment, washed with deionized water, and the centrifugation speed is 7000 r / min; in Step 3, the ultrasonic frequency is 1.5 MHz and the ultrasonic power is 200 W; in Step 4, the stirring speed is 650 r / min; in Step 5, the curing process is: first cure at 85 °C for 3.5 hours, and then cure at 130 °C for 2.5 hours; in Step 6, the hot press is set with a hot pressing temperature of 235 °C, a pressure of 88 kg / cm 2 , the lamination time is 18.5 h.

[0022] The technical effects and advantages of the present invention:

[0023] 1. A flame-retardant and toughened epoxy resin copper clad laminate prepared by using the raw material formula of the present invention. By adding epoxidized lignin during the synthesis of epoxy resin, the mechanical properties of epoxy resin can be effectively improved, thereby ensuring the toughness of epoxy resin-based materials. Adding a composite LDH flame retardant material to the epoxy resin-based materials can effectively improve the flame retardant performance of the epoxy resin material, while ensuring the mechanical properties of the epoxy resin material after adding LDH, and ensuring the flame retardant performance and toughening effect of the epoxy resin-based materials when applied in the copper clad laminate; epoxidized lignin can be evenly dispersed into the epoxy resin cross-linking system under the synergistic dissolution of polyethylene glycol, which is beneficial to the improvement of mechanical properties; the rigid benzene ring structure in the epoxidized lignin structure can be incorporated into the epoxy resin cross-linking network through chemical bonds under the curing cross-linking reaction of polyetheramine curing agent, thereby significantly increasing the strength of the epoxy resin cured product; the mechanical properties of the epoxy resin system modified by epoxidized lignin under the synergistic dispersion of polyethylene glycol, thereby ensuring the toughness of the epoxy resin copper clad laminate; aluminum chloride hexahydrate and magnesium chloride hexahydrate in the flame retardant are processed to form MgAl-LDH, MgAl-LDH is compounded with hydroxyl-functionalized carbon nanotubes, and used as a uniform mechanical support skeleton. The one-dimensional carbon nanotubes are tightly and evenly wrapped by two-dimensional MgAl-LDH nanosheets, which can effectively reduce the damage of MgAl-LDH nanosheets and subsequent incorporation of copper molybdate nanoparticles to the mechanical properties of the epoxy resin material; the copper molybdate nanoparticles are evenly loaded on the outside of the support skeleton, and the uniform loading of the copper molybdate nanoparticles can significantly inhibit the release of harmful flue gas during the combustion process of the epoxy resin material; the endothermic decomposition of MgAl-LDH and copper molybdate nanoparticles can absorb a large amount of heat and exert a cooling effect on the combustion area and the epoxy resin material; the metal oxides (aluminum oxide, magnesium oxide, MoO 3 and Cu 2 O) generated by the thermal decomposition of MgAl-LDH and copper molybdate nanoparticles and the dense carbon layer catalytically formed thereby jointly play a role of an isolation barrier, which can effectively enhance the flame retardant performance of the epoxy resin material;

[0024] 2. In the present invention, aluminum chloride hexahydrate, copper molybdate nanometer, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes and urea are added to deionized water and subjected to ultrasonic treatment, which can effectively inhibit the agglomeration of hydroxyl-functionalized carbon nanotubes and fully disperse them in the liquid phase system. Then, sodium hydroxide is added and stirred, heated, cooled, centrifuged and washed, so that sodium hydroxide reacts with aluminum chloride and magnesium chloride in the liquid phase system to form aluminum hydroxide and magnesium hydroxide precipitates. The layered double hydroxide (MgAl-LDH) of aluminum hydroxide and magnesium hydroxide and hydroxyl-functionalized carbon nanotubes can be effectively compounded to form a mechanical support framework, and copper molybdate nanometer particles are loaded on the mechanical support framework to form a composite flame retardant; Epoxidized lignin and polyethylene glycol are subjected to ultrasonic treatment to uniformly dissolve and disperse epoxidized lignin into polyethylene glycol, which is convenient for subsequent uniform dispersion of epoxidized lignin into the epoxy resin crosslinking network, thereby ensuring the toughening treatment effect on the epoxy resin material; Polyetheramine and bisphenol A diglycidyl ether are blended with the modified mixture, which can effectively ensure that the epoxidized lignin and the composite flame retardant in the modified mixture are added to the crosslinking network of epoxy resin, and can effectively improve the flame retardant performance and toughening effect of the epoxy resin material. Detailed implementation mode

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] Example 1:

[0027] The present invention provides a flame-retardant and toughened epoxy resin copper clad laminate, which includes an electronic glass fiber cloth, a copper foil and an impregnating material; the raw materials of the impregnating material are calculated by weight percentage as follows: 44 g of epoxidized lignin, 140 g of polyethylene glycol PEG-200, 192 g of polyetheramine, 29 g of a flame retardant, and 595 g of bisphenol A diglycidyl ether; the raw materials of the flame retardant are calculated by weight percentage as follows: 3.219 g of aluminum chloride hexahydrate, 1.334 g of copper molybdate nanometer, 6.409 g of magnesium chloride hexahydrate, 0.2755 g of hydroxyl-functionalized carbon nanotubes, 4.089 g of sodium hydroxide, and 13.6735 g of urea;

[0028] The preparation method of the above epoxidized lignin is as follows: Dissolve lignin in sodium hydroxide solution with pH = 10, add epichlorohydrin and tetrabutylammonium bromide thereto, react at 60 °C for 3 h, cool to room temperature, add appropriate amount of tetrabutylammonium bromide and sodium hydroxide and continue to react for 8 h; after the reaction is completed, add water for precipitation, collect and dry to obtain epoxidized lignin; before the reaction in a 60 °C environment, the weight ratio of lignin, epichlorohydrin and tetrabutylammonium bromide is 10∶100∶1;

[0029] Lignin was purchased from Wuhan Xinxin Jiali Biotechnology Co., Ltd., product number: L552047; Epichlorohydrin was purchased from Shanghai Zhenzhun Biotechnology Co., Ltd., product number: IR-10280; Tetrabutylammonium bromide was purchased from Sinopharm Chemical Reagent Co., Ltd., Sinopharm code: 30173814; Polyethylene glycol PEG-200 was purchased from Sinopharm Chemical Reagent Co., Ltd., Sinopharm code: 30150628; Polyetheramine was purchased from Polyetheramine D-230 of Sinopharm Chemical Reagent Co., Ltd., Sinopharm code: XW904610001; Bisphenol A diglycidyl ether was purchased from Shanghai Kangtuo Chemical Co., Ltd., product number: HH5221VHZARB; Aluminum chloride hexahydrate was purchased from Sinopharm Chemical Reagent Co., Ltd., Sinopharm code: 20000818; Nano copper molybdate was purchased from Hubei Zhongao Nano Materials Technology Co., Ltd.; Magnesium chloride hexahydrate was purchased from Sinopharm Chemical Reagent Co., Ltd., Sinopharm code: C197530010; Hydroxyl-functionalized carbon nanotubes were purchased from Sinopharm Chemical Reagent Co., Ltd., Sinopharm code: XW30806856619; Sodium hydroxide was purchased from Sinopharm Chemical Reagent Co., Ltd., Sinopharm code: 10019719; Urea was purchased from Shanghai Yuanye Biotechnology Co., Ltd., product number: S30375;

[0030] The present invention also provides a preparation method of a flame-retardant toughened epoxy copper clad laminate, and the specific preparation steps are as follows:

[0031] Step 1: Weigh epoxidized lignin, polyethylene glycol, polyetheramine, bisphenol A diglycidyl ether in the impregnating material raw materials and aluminum chloride hexahydrate, nano copper molybdate, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes, sodium hydroxide, urea in the flame retardant raw materials;

[0032] Step 2: Add aluminum chloride hexahydrate, nano copper molybdate, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes and urea in Step 1 into deionized water, perform ultrasonic treatment for 30 minutes, add sodium hydroxide, then perform ultrasonic treatment for 8 minutes, perform magnetic stirring and heating reaction treatment for 3.5 hours, cool to room temperature, perform centrifugal washing treatment until the pH of the centrifugal supernatant is 7.0, filter by suction to obtain the product and then perform drying treatment to obtain the flame retardant;

[0033] Step 3: Add the epoxidized lignin in Step 1 and the flame retardant in Step 2 into the polyethylene glycol in Step 1, and perform ultrasonic treatment for 15 minutes to obtain a modified mixture;

[0034] Step 4: Add the polyetheramine and bisphenol A diglycidyl ether in Step 1 into the modified mixture in Step 3, and stir for 1.0 hour to obtain an impregnating material;

[0035] Step 5: Immerse the electronic glass fiber cloth in the impregnating material prepared in Step 4 for 27 minutes, cure for 6 hours, and cool to room temperature after curing to obtain an epoxy resin-based semi-cured sheet;

[0036] Step 6: Place a copper foil on each of the upper and lower surfaces of the epoxy resin-based semi-cured sheet, and then send it into a hot press for hot pressing. After hot pressing, a flame-retardant toughened epoxy resin copper clad laminate is obtained.

[0037] In Step 2, the weight ratio of the total weight of aluminum chloride hexahydrate, copper molybdate nanometer, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes, and urea to the weight of deionized water is 1:14, the ultrasonic frequency is 1.4 MHz, the ultrasonic power is 160 W, the magnetic stirring speed is 500 r / min, the heating temperature is 100 °C, the water liquid is subjected to condensation reflux treatment during heating, washing treatment is performed with deionized water, and the centrifugation speed is 6000 r / min; in Step 3, the ultrasonic frequency is 1.4 MHz and the ultrasonic power is 160 W; in Step 4, the stirring speed is 550 r / min; in Step 5, the curing process is: first cure at 80 °C for 3 hours, and then cure at 120 °C for 3 hours; in Step 6, the hot press is set with a hot pressing temperature of 230 °C, a pressure of 85 kg / cm 2 and the lamination time is 18 h.

[0038] Example 2:

[0039] Differing from Example 1, the raw materials of the impregnating material are calculated by weight percentage as: 48 g of epoxidized lignin, 150 g of polyethylene glycol PEG-200, 212 g of polyetheramine, 31 g of flame retardant, 559 g of bisphenol A diglycidyl ether; the raw materials of the flame retardant are calculated by weight percentage as: 3.689 g of aluminum chloride hexahydrate, 1.674 g of copper molybdate nanometer, 7.099 g of magnesium chloride hexahydrate, 0.3565 g of hydroxyl-functionalized carbon nanotubes, 4.619 g of sodium hydroxide, 13.5625 g of urea.

[0040] Example 3:

[0041] Different from Examples 1-2, the raw materials of the impregnating material are calculated by weight percentage as follows: 46 g of epoxidized lignin, 145 g of polyethylene glycol, 202 g of polyetheramine, 30 g of flame retardant, and 577 g of bisphenol A diglycidyl ether; the raw materials of the flame retardant are calculated by weight percentage as follows: 3.45 g of aluminum chloride hexahydrate, 1.50 g of nano copper molybdate, 6.75 g of magnesium chloride hexahydrate, 0.315 g of hydroxyl-functionalized carbon nanotubes, 4.35 g of sodium hydroxide, and 13.635 g of urea.

[0042] Example 4:

[0043] Different from Example 3, in Step 2, the weight ratio of the total weight of aluminum chloride hexahydrate, nano copper molybdate, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes and urea to the weight of deionized water is 1:17, the ultrasonic frequency is 1.5 MHz, the ultrasonic power is 200 W, the magnetic stirring speed is 600 r / min, the heating temperature is 100 °C, the water liquid is subjected to condensation reflux treatment during the heating process, washed with deionized water, and the centrifugation speed is 7000 r / min; in Step 3, the ultrasonic frequency is 1.5 MHz and the ultrasonic power is 200 W; in Step 4, the stirring speed is 650 r / min; in Step 5, the curing process is as follows: first cure at 85 °C for 3.5 hours, and then cure at 130 °C for 2.5 hours; in Step 6, the hot press is set with a hot pressing temperature of 235 °C, a pressure of 88 kg / cm 2 , and the pressing time is 18.5 h.

[0044] Comparative Example 1:

[0045] Different from Example 4: The raw materials of the impregnating material are calculated by weight percentage as follows: 145 g of polyethylene glycol, 202 g of polyetheramine, 30 g of flame retardant, and 577 g of bisphenol A diglycidyl ether; the raw materials of the flame retardant are calculated by weight percentage as follows: 3.45 g of aluminum chloride hexahydrate, 1.50 g of nano copper molybdate, 6.75 g of magnesium chloride hexahydrate, 0.315 g of hydroxyl-functionalized carbon nanotubes, 4.35 g of sodium hydroxide, and 13.635 g of urea;

[0046] The preparation method of the flame-retardant and toughened epoxy resin copper clad laminate is as follows:

[0047] Step 1: Weigh polyethylene glycol, polyetheramine, bisphenol A diglycidyl ether in the raw materials of the impregnating material and aluminum chloride hexahydrate, nano copper molybdate, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes, sodium hydroxide, and urea in the raw materials of the flame retardant;

[0048] Step 2: Add aluminum chloride hexahydrate, copper molybdate nanometer, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes, and urea in Step 1 into deionized water, perform ultrasonic treatment for 30 minutes, add sodium hydroxide, then perform ultrasonic treatment for 8 minutes, carry out magnetic stirring and heating reaction for 3.5 hours. After cooling to room temperature, perform centrifugal washing treatment until the pH of the centrifugal supernatant is 7.0, then filter by suction to obtain the product and perform drying treatment to obtain the flame retardant;

[0049] Step 3: Add the flame retardant in Step 2 into the polyethylene glycol in Step 1, and perform ultrasonic treatment for 15 minutes to obtain a modified mixture;

[0050] Step 4: Add the polyetheramine and bisphenol A diglycidyl ether in Step 1 into the modified mixture in Step 3, and stir for 1.0 hour to obtain an impregnating material;

[0051] Step 5: Immerse the electronic glass fiber cloth in the impregnating material prepared in Step 4 for 27 minutes, cure for 6 hours, and cool to room temperature after curing to obtain an epoxy resin-based semi-cured sheet;

[0052] Step 6: Place a copper foil on each of the upper and lower surfaces of the epoxy resin-based semi-cured sheet, and then send it into a hot press for hot pressing treatment. After the hot pressing treatment, a flame-retardant and toughened epoxy resin copper clad laminate is obtained.

[0053] Comparative Example 2:

[0054] The difference from Example 4 is that: the raw materials of the impregnating material are calculated by weight percentage as follows: 46 g of epoxidized lignin, 145 g of tetrahydrofuran, 202 g of polyetheramine, 30 g of flame retardant, 577 g of bisphenol A diglycidyl ether; the raw materials of the flame retardant are calculated by weight percentage as follows: 3.45 g of aluminum chloride hexahydrate, 1.50 g of copper molybdate nanometer, 6.75 g of magnesium chloride hexahydrate, 0.315 g of hydroxyl-functionalized carbon nanotubes, 4.35 g of sodium hydroxide, 13.635 g of urea;

[0055] Preparation method of a flame-retardant and toughened epoxy resin copper clad laminate, the specific preparation steps are as follows:

[0056] Step 1: Weigh epoxidized lignin, tetrahydrofuran, polyetheramine, bisphenol A diglycidyl ether in the raw materials of the impregnating material, and aluminum chloride hexahydrate, copper molybdate nanometer, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes, sodium hydroxide, urea in the raw materials of the flame retardant;

[0057] Step 2: Add aluminum chloride hexahydrate, copper molybdate nanometer, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes, and urea in Step 1 into deionized water, perform ultrasonic treatment for 30 minutes, add sodium hydroxide, then perform ultrasonic treatment for 8 minutes, conduct magnetic stirring and heating reaction treatment for 3.5 hours. After cooling to room temperature, perform centrifugal washing treatment until the pH of the centrifugal supernatant is 7.0, and then perform suction filtration to obtain the product and conduct drying treatment to obtain the flame retardant;

[0058] Step 3: Add the epoxidized lignin in Step 1 and the flame retardant in Step 2 into the tetrahydrofuran in Step 1, and perform ultrasonic treatment for 15 minutes to obtain a modified mixture;

[0059] Step 4: Add the polyetheramine and bisphenol A diglycidyl ether in Step 1 into the modified mixture in Step 3, and conduct stirring treatment for 1.0 hour to obtain an impregnating material;

[0060] Step 5: Immerse the electronic glass fiber cloth in the impregnating material prepared in Step 4 for 27 minutes, cure for 6 hours, and cool to room temperature after curing to obtain an epoxy resin-based semi-cured sheet;

[0061] Step 6: Place a copper foil on each of the upper and lower surfaces of the epoxy resin-based semi-cured sheet, and then send it into a hot press for hot pressing treatment. After the hot pressing treatment, a flame-retardant and toughened epoxy resin copper clad laminate is obtained.

[0062] Comparative Example 3:

[0063] The difference from Example 4 is that: the raw materials of the impregnating material are calculated by weight percentage as follows: 46 g of epoxidized lignin, 145 g of polyethylene glycol, 202 g of polyetheramine, 30 g of flame retardant, and 577 g of bisphenol A diglycidyl ether; the raw materials of the flame retardant are calculated by weight percentage as follows: 3.45 g of aluminum chloride hexahydrate, 6.75 g of magnesium chloride hexahydrate, 0.315 g of hydroxyl-functionalized carbon nanotubes, 4.35 g of sodium hydroxide, and 13.635 g of urea;

[0064] A preparation method of a flame-retardant and toughened epoxy resin copper clad laminate, and the specific preparation steps are as follows:

[0065] Step 1: Weigh the epoxidized lignin, polyethylene glycol, polyetheramine, bisphenol A diglycidyl ether in the raw materials of the impregnating material, and aluminum chloride hexahydrate, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes, sodium hydroxide, and urea in the raw materials of the flame retardant;

[0066] Step 2: Add aluminum chloride hexahydrate, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes, and urea in Step 1 into deionized water, perform ultrasonic treatment for 30 minutes, add sodium hydroxide, then perform ultrasonic treatment for 8 minutes, carry out magnetic stirring and heating reaction treatment for 3.5 hours. After cooling to room temperature, perform centrifugal washing treatment until the pH of the centrifugal supernatant is 7.0, filter by suction to obtain the product, and then perform drying treatment to obtain the flame retardant;

[0067] Step 3: Add the epoxidized lignin in Step 1 and the flame retardant in Step 2 into the polyethylene glycol in Step 1, and perform ultrasonic treatment for 15 minutes to obtain a modified mixture;

[0068] Step 4: Add the polyetheramine and bisphenol A diglycidyl ether in Step 1 into the modified mixture in Step 3, and perform stirring treatment for 1.0 hour to obtain an impregnating material;

[0069] Step 5: Immerse the electronic glass fiber cloth in the impregnating material prepared in Step 4 for 27 min, cure for 6 h, and cool to room temperature after curing to obtain an epoxy resin-based semi-cured sheet;

[0070] Step 6: Place a copper foil on each of the upper and lower surfaces of the epoxy resin-based semi-cured sheet, and then send it into a hot press for hot pressing treatment. After the hot pressing treatment, a flame-retardant and toughened epoxy resin copper clad laminate is obtained.

[0071] Comparative Example 4:

[0072] The difference from Example 3 is that: the raw materials of the impregnating material are calculated by weight percentage as follows: 46 g of epoxidized lignin, 145 g of polyethylene glycol, 202 g of polyetheramine, 30 g of flame retardant, 577 g of bisphenol A diglycidyl ether; the raw materials of the flame retardant are calculated by weight percentage as follows: 3.45 g of aluminum chloride hexahydrate, 1.50 g of copper molybdate nanometer, 6.75 g of magnesium chloride hexahydrate, 4.35 g of sodium hydroxide, 13.635 g of urea;

[0073] Preparation method of a flame-retardant and toughened epoxy resin copper clad laminate, the specific preparation steps are as follows:

[0074] Step 1: Weigh the epoxidized lignin, polyethylene glycol, polyetheramine, and bisphenol A diglycidyl ether in the raw materials of the impregnating material, and aluminum chloride hexahydrate, copper molybdate nanometer, magnesium chloride hexahydrate, sodium hydroxide, and urea in the raw materials of the flame retardant;

[0075] Step 2: Add aluminum chloride hexahydrate, copper molybdate nanometer, magnesium chloride hexahydrate, and urea in Step 1 into deionized water, perform ultrasonic treatment for 30 minutes, add sodium hydroxide, then perform ultrasonic treatment for 8 minutes, carry out magnetic stirring and heating reaction treatment for 3.5 hours. After cooling to room temperature, perform centrifugal washing treatment until the pH of the centrifugal supernatant is 7.0, filter by suction to obtain the product, and then perform drying treatment to obtain the flame retardant;

[0076] Step 3: Add the epoxidized lignin in Step 1 and the flame retardant in Step 2 into the polyethylene glycol in Step 1, and perform ultrasonic treatment for 15 minutes to obtain a modified mixture;

[0077] Step 4: Add the polyetheramine and bisphenol A diglycidyl ether in Step 1 into the modified mixture in Step 3, and perform stirring treatment for 1.0 hour to obtain an impregnating material;

[0078] Step 5: Immerse the electronic glass fiber cloth in the impregnating material prepared in Step 4 for 27 min, cure for 6 h, and cool to room temperature after curing to obtain an epoxy resin-based semi-cured sheet;

[0079] Step 6: Place a copper foil on each of the upper and lower surfaces of the epoxy resin-based semi-cured sheet, and then send it into a hot press for hot pressing treatment. After the hot pressing treatment, a flame-retardant and toughened epoxy resin copper clad laminate is obtained.

[0080] Perform detection treatment on the epoxy resin-based semi-cured sheets in the comparative examples and examples of the present invention for the flame-retardant and toughened epoxy resin copper clad laminate:

[0081] Impact strength test: Detect the impact strength according to the standard of GB / T1843-2008;

[0082] Elongation at break test: Detect the elongation at break according to the standard of GB / T1040-1992;

[0083] Limiting oxygen index performance test: Detect the limiting oxygen index according to the standard of GB / T2406.2-2009; The results are shown in Table 1: Table 1:

[0084] <![CDATA[Impact strength (kJ / m 2 )]]> Elongation at break (%) Limiting oxygen index (%) Comparative Example 1 19.8 7.3 31.1 Comparative Example 2 21.3 7.6 30.2 Comparative Example 3 24.2 9.2 29.6 Comparative Example 4 22.6 8.4 28.6 Example 1 25.4 10.8 32.1 Example 2 25.8 10.9 32.4 Example 3 26.3 11.4 32.8 Example 4 26.4 11.6 33.1

[0085] As can be seen from the above table: For the flame-retardant and toughened epoxy resin copper clad laminate of the present invention, by adding epoxidized lignin during the synthesis of epoxy resin, the mechanical properties of epoxy resin can be effectively improved, thereby ensuring the toughness of the epoxy resin-based material. By adding a composite LDH flame retardant material to the epoxy resin-based material, the flame retardant performance of the epoxy resin material can be effectively improved, while ensuring the mechanical properties of the epoxy resin material after adding LDH, and ensuring the flame retardant performance and toughening effect of the epoxy resin-based material when it is applied in the copper clad laminate.

[0086] In the present invention, polyethylene glycol is added to the impregnating material, which can dissolve epoxidized lignin, make it uniformly dispersed and incorporated into the epoxy resin crosslinking network. At the same time, polyethylene glycol can be used as a toughening agent for epoxy resin to improve the toughness of the epoxy resin cured product. However, only adding polyethylene glycol often significantly reduces the mechanical strength and rigidity after the curing reaction of epoxy resin; under the synergistic dissolution of polyethylene glycol, epoxidized lignin can be uniformly dispersed into the epoxy resin crosslinking system, which is beneficial to the improvement of mechanical properties; the rigid benzene ring structure in the structure of epoxidized lignin can be incorporated into the epoxy resin crosslinking network through chemical bonds under the curing crosslinking reaction of polyetheramine curing agent, thus significantly increasing the strength of the epoxy resin cured product; the mechanical properties of the epoxy resin system modified by epoxidized lignin under the synergistic dispersion of polyethylene glycol are improved, thereby ensuring the toughness of the epoxy resin copper clad laminate; aluminum chloride hexahydrate and magnesium chloride hexahydrate in the flame retardant are processed to form MgAl-LDH. Hydroxyl-functionalized carbon nanotubes are used. The oxygen-containing groups on the surface of the carbon nanotubes interact with the epoxy groups in the epoxy resin to improve the compatibility between the inorganic carbon nanotubes and the epoxy resin. With the network structure formed by the intertwining of carbon nanotubes, when the epoxy resin material is subjected to external force, the carbon nanotube network can disperse the external force intensity, thereby improving the ductility and mechanical properties of the epoxy resin material. The excellent thermal stability of the carbon nanotubes can cause the epoxy resin material to form a dense carbon layer when heated, playing a role in isolating oxygen in the environment and blocking the heat of the heat source; MgAl-LDH is compounded with hydroxyl-functionalized carbon nanotubes and used as a uniform mechanical support skeleton. The one-dimensional carbon nanotubes are tightly and uniformly wrapped by two-dimensional MgAl-LDH nanosheets, which can effectively reduce the damage of MgAl-LDH nanosheets and subsequent incorporation of copper molybdate nanoparticles to the mechanical properties of the epoxy resin material; copper molybdate nanoparticles are uniformly loaded on the outside of the support skeleton. The uniform loading of copper molybdate nanoparticles can significantly inhibit the release of harmful flue gas during the combustion process of the epoxy resin material; the endothermic decomposition of MgAl-LDH and copper molybdate nanoparticles can absorb a large amount of heat and exert a cooling effect on the combustion area and the epoxy resin material; the metal oxides (aluminum oxide, magnesium oxide, MoO 3 and Cu 2 O) generated by the thermal decomposition of MgAl-LDH and copper molybdate nanoparticles and the dense carbon layer catalytically formed therefrom together play a role in isolation and barrier, which can inhibit the release of combustible organic volatiles and harmful flue gas from the epoxy resin material and isolate the oxygen supply and heat radiation from the combustion area to the epoxy resin material, effectively enhancing the flame retardant performance of the epoxy resin material;

[0087] In Step 2, aluminum chloride hexahydrate, copper molybdate nanometer, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes and urea are added to deionized water for ultrasonic treatment, which can effectively inhibit the agglomeration of hydroxyl-functionalized carbon nanotubes and make them fully dispersed in the liquid phase system. Then, sodium hydroxide is added for stirring, heating, cooling, centrifuging and washing, so that sodium hydroxide reacts with aluminum chloride and magnesium chloride in the liquid phase system to form aluminum hydroxide and magnesium hydroxide precipitates, which can effectively compound the layered double hydroxide (MgAl-LDH) of aluminum hydroxide and magnesium hydroxide with hydroxyl-functionalized carbon nanotubes to form a mechanical support framework, and copper molybdate nanometer particles are loaded on the mechanical support framework to form a composite flame retardant; in Step 3, epoxidized lignin and polyethylene glycol are subjected to ultrasonic treatment to make the epoxidized lignin uniformly dissolve and disperse in the polyethylene glycol, which is convenient for the subsequent uniform dispersion of the epoxidized lignin into the epoxy resin crosslinked network, thereby ensuring the toughening treatment effect on the epoxy resin material; in Step 4, polyetheramine and bisphenol A diglycidyl ether are blended with the modified mixture, which can effectively ensure that the epoxidized lignin and the composite flame retardant in the modified mixture are added into the crosslinked network of the epoxy resin, and can effectively improve the flame retardant performance and toughening effect of the epoxy resin material; in Step 5, the electronic glass fiber cloth is impregnated and cured in the impregnating material to form a semi-cured sheet based on epoxy resin; in Step 6, two copper foils are respectively thermocompression bonded on the upper and lower surfaces of the semi-cured sheet based on epoxy resin to obtain a flame retardant and toughened epoxy resin copper clad laminate.

[0088] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent substitution on some of the technical features. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A flame retardant toughened epoxy resin copper clad laminate, characterized in that: The invention comprises electronic glass fiber cloth, copper foil and impregnation material; the raw materials of the impregnation material are calculated by weight percentage as follows: 4.4-4.8% of epoxidized lignin, 14.0-15.0% of polyethylene glycol, 19.2-21.2% of polyether amine, 2.9-3.1% of flame retardant, and the rest is bisphenol A diglycidyl ether.

2. The flame retardant toughened epoxy resin copper clad laminate according to claim 1, characterized in that: The polyethylene glycol is one or a combination of PEG-200, PEG-400 and PEG-600.

3. The flame retardant toughened epoxy resin copper clad laminate according to claim 1, characterized in that: The raw materials of the flame retardant are calculated by weight percentage: 11.1-11.9% of aluminum chloride hexahydrate, 4.6-5.4% of nano copper molybdate, 22.1-22.9% of magnesium chloride hexahydrate, 0.95-1.15% of hydroxyl functionalized carbon nanotubes, 14.1-14.9% of sodium hydroxide, and the rest is urea.

4. The flame retardant toughened epoxy resin copper clad laminate according to claim 3, characterized in that: The raw materials of the impregnating material are calculated by weight percentage as follows: 4.5-4.7% of epoxidized lignin, 14.3-14.7% of polyethylene glycol, 19.7-20.7% of polyether amine, 2.95-3.05% of flame retardant, and the rest is bisphenol A diglycidyl ether; the raw materials of the flame retardant are calculated by weight percentage as follows: 11.4-11.6% of aluminum chloride hexahydrate, 4.3-5.1% of nano copper molybdate, 22.4-22.6% of magnesium chloride hexahydrate, 1.02-1.08% of hydroxyl functionalized carbon nanotubes, 14.4-14.6% of sodium hydroxide, and the rest is urea.

5. The flame retardant toughened epoxy resin copper clad laminate according to claim 3, characterized in that: The raw materials of the impregnating material are calculated by weight percentage as follows: 4.6% of epoxidized lignin, 14.5% of polyethylene glycol, 20.2% of polyetheramine, 3.0% of flame retardant, and the rest is bisphenol A diglycidyl ether; the raw materials of the flame retardant are calculated by weight percentage as follows: 11.5% of aluminum chloride hexahydrate, 5.0% of nano copper molybdate, 22.5% of magnesium chloride hexahydrate, 1.05% of hydroxyl functionalized carbon nanotubes, 14.5% of sodium hydroxide, and the rest is urea.

6. A method for preparing a flame retardant toughened epoxy resin copper clad laminate, characterized in that: The specific preparation steps are as follows: Step 1: weighing epoxidized lignin, polyethylene glycol, polyetheramine, bisphenol A diglycidyl ether in the impregnation material raw materials and aluminum chloride hexahydrate, nano copper molybdate, magnesium chloride hexahydrate, hydroxyl functionalized carbon nanotubes, sodium hydroxide, and urea in the flame retardant raw materials; Step 2: adding aluminum chloride hexahydrate, nano copper molybdate, magnesium chloride hexahydrate, hydroxyl-functionalized carbon nanotubes and urea in step 1 to deionized water for ultrasonic treatment for 20 to 40 minutes, adding sodium hydroxide, and then ultrasonic treatment for 5 to 10 minutes, magnetic stirring heating reaction treatment for 3 to 4 hours, cooling to room temperature, centrifuging and washing until the pH of the centrifugal supernatant is 7.0, filtering to obtain the product and drying it to obtain a flame retardant; Step 3: adding the epoxidized lignin in step 1 and the flame retardant in step 2 to the polyethylene glycol in step 1, and performing ultrasonic treatment for 10 to 20 minutes to obtain a modified mixture; Step 4: adding the polyetheramine and bisphenol A diglycidyl ether in step 1 to the modified mixed material in step 3, stirring for 0.5 to 1.5 hours to obtain an impregnated material; Step 5: Immerse the electronic glass fiber cloth in the impregnating material prepared in step 4 for 25 to 30 minutes, cure for 5.0 to 6.0 hours, and cool to room temperature after curing to obtain an epoxy resin-based prepreg; Step 6: Place a copper foil on the upper and lower surfaces of the epoxy resin-based prepreg, respectively, and then send it into a hot press for hot pressing. After the hot pressing treatment, a flame-retardant toughened epoxy resin copper clad laminate is obtained.

7. The method for preparing a flame retardant toughened epoxy resin copper clad laminate according to claim 6, characterized in that: In step 2, the weight ratio of the total weight of aluminum chloride hexahydrate, nano copper molybdate, magnesium chloride hexahydrate, hydroxyl functionalized carbon nanotubes and urea to deionized water is 1:14-20, the ultrasonic frequency is 1.4-1.6 MHz, the ultrasonic power is 160-240 W, the magnetic stirring speed is 500-700 r / min, the heating temperature is 100° C. During the heating process, the water liquid is condensed and refluxed, and deionized water is used for washing. The centrifugal speed is 6000-8000 r / min.

8. The method for preparing a flame retardant toughened epoxy resin copper clad laminate according to claim 7, characterized in that: In step 3, the ultrasonic frequency is 1.4-1.6 MHz, and the ultrasonic power is 160-240 W; in step 4, the stirring speed is 550-750 r / min; in step 5, the curing process is: first curing at 80-90°C for 3-4 hours, and then curing at 120-140°C for 2-3 hours; in step 6, the hot press is set to a hot pressing temperature of 230-240°C and a pressure of 85-90 kg / cm 2 The pressing time is 18 to 19 hours.

9. A method for preparing a flame retardant toughened epoxy resin copper clad laminate according to claim 8, characterized in that: In step 2, the weight ratio of the total weight of aluminum chloride hexahydrate, nano copper molybdate, magnesium chloride hexahydrate, hydroxyl functionalized carbon nanotubes and urea to deionized water is 1:16-18, the ultrasonic frequency is 1.45-1.55 MHz, the ultrasonic power is 190-210 W, the magnetic stirring speed is 560-640 r / min, the heating temperature is 100° C., the water is condensed and refluxed during the heating process, deionized water is used for washing, and the centrifugal speed is 650 0~7500r / min; in step three, the ultrasonic frequency is 1.45~1.55MHz, and the ultrasonic power is 190~210W; in step four, the stirring speed is 600~700r / min; in step five, the curing process is: first curing at 82~88℃ for 3~4 hours, and then curing at 125~135℃ for 2~3 hours; in step six, the hot press machine is set to a hot pressing temperature of 233~237℃ and a pressure of 85~90kg / cm 2 The pressing time is 18 to 19 hours.

10. The method for preparing a flame retardant toughened epoxy resin copper clad laminate according to claim 8, characterized in that: In step 2, the weight ratio of the total weight of aluminum chloride hexahydrate, nano copper molybdate, magnesium chloride hexahydrate, hydroxyl functionalized carbon nanotubes and urea to deionized water is 1:17, the ultrasonic frequency is 1.5 MHz, the ultrasonic power is 200 W, the magnetic stirring speed is 600 r / min, the heating temperature is 100° C., the water liquid is subjected to condensation reflux treatment during the heating process, deionized water is used for washing treatment, and the centrifugal speed is 7000 r / min; in step 3, the ultrasonic frequency is 1.5 MHz, the ultrasonic power is 200 W; in step 4, the stirring speed is 650 r / min; in step 5, the curing process is: first curing at 85° C. for 3.5 hours, and then curing at 130° C. for 2.5 hours; in step 6, the hot press is set to a hot pressing temperature of 235° C. and a pressure of 88 kg / cm 2 , the pressing time is 18.5h.