Alaralkyl epoxy resin glue solution for copper-clad plate and preparation method thereof

Abstract

According to the aralkyl epoxy resin glue solution for the copper-clad plate and the preparation method of the aralkyl epoxy resin glue solution, under the condition that a flexibilizer and a flame retardant are low in doping amount, the tensile strength and the bending strength of a copper-clad plate cured sheet can be effectively improved, the toughness of the copper-clad plate can be effectively improved, and then the safety of the copper-clad plate is effectively improved; the flame retardant property of the copper-clad plate cured sheet can be effectively improved; the doping amounts of the flexibilizer and the flame retardant in the epoxy resin glue solution of the copper-clad plate are small, other functional raw materials can be conveniently added into the epoxy resin glue solution, the copper-clad plate glue solution can be subjected to multifunctional adjustment, and the problems of toughness and flame retardance of the copper-clad plate do not need to be worried about; the functionalized molybdenum disulfide nanosheets show more uniform dispersibility in an epoxy resin matrix, and the stronger the crack resistance and interface resistance around the nanosheets are, the better the toughness improvement effect of the composite material is macroscopically represented; the composite flame retardant has a synergistic flame-retardant effect and low-additive efficient flame-retardant performance.

Description

Technical Field

[0001] This invention relates to the field of epoxy resin adhesive technology, and more specifically, to an aralkyl epoxy resin adhesive for copper clad laminates and its preparation method. Background Technology

[0002] Copper-clad laminate (CCL) refers to copper foil laminate, a sheet-like material made by impregnating electronic fiberglass cloth or other reinforcing materials with resin, covering one or both sides with copper foil, and then hot-pressing. Phenolic-aryl alkyl epoxy resin is a resin with excellent heat resistance, flame retardancy, moisture resistance, and electrical insulation properties obtained by using aryl alkyl ethers or aryl alkyl alcohols as raw materials, undergoing a Freidel-Craft reaction under the action of a catalyst, and then epoxidizing it. It has high heat resistance, low moisture absorption, inherent flame retardancy, low coefficient of thermal expansion at high temperatures, and low dielectric constant. The cured resin exhibits excellent heat resistance and chemical stability. The toughness of epoxy resin is mainly determined by its molecular structure and curing network. Its impact resistance can be significantly improved by adding toughening agents, introducing dynamic covalent bonds, or constructing special microstructures. Conventional epoxy resins are brittle due to their rigid molecular chains and high cross-linking density. However, the toughness of both ordinary epoxy resins and phenol-aryl alkyl epoxy resins needs to be improved before they can be used in copper-clad laminates.

[0003] Currently, the amount of toughening agents used in epoxy resin adhesives is generally large (5% to 30%), which leads to a reduction in the amount of other raw materials used. This hinders the addition of other functional raw materials to epoxy resin adhesives and makes it difficult to make multifunctional adjustments to epoxy resin adhesives. Summary of the Invention

[0004] To overcome the above-mentioned defects of the prior art, embodiments of the present invention provide an aralkyl epoxy resin adhesive for copper clad laminates and a method for preparing the same.

[0005] An aralkyl epoxy resin adhesive for copper clad laminates comprises, by weight percentage: 0.75-1.05% nano-filler toughening agent, 5.5-6.5% composite flame retardant, 22-24% curing agent, 1.8-2.2% curing accelerator, and the balance being composite epoxy resin.

[0006] Furthermore, the nanofiller toughening agent is functionalized molybdenum disulfide nanosheets, and the raw materials of the functionalized molybdenum disulfide nanosheets include glycine and molybdenum disulfide, and the mass ratio of glycine to molybdenum disulfide is (15-20):1.

[0007] Furthermore, the composite flame retardant comprises a flame retardant and a CA-DDS charring agent, wherein the mass ratio of the flame retardant to the CA-DDS charring agent is 6:4; the raw materials of the flame retardant include intermediate product a and DOPO, wherein the molar ratio of intermediate product a to DOPO is 1:(1.9-2.1); the raw materials of intermediate product a include hexachlorocyclotriphosphazene (HCCP), 2,2'-dihydroxybiphenyl and p-hydroxybenzaldehyde, wherein the molar ratio of hexachlorocyclotriphosphazene (HCCP), 2,2'-dihydroxybiphenyl and p-hydroxybenzaldehyde is 1:(2.0-2.4):(2.0-2.2).

[0008] Furthermore, the composite epoxy resin includes epoxy resin and phenol-aryl type epoxy resin, wherein the mass ratio of epoxy resin to phenol-aryl type epoxy resin is (2.0~3.0):1.

[0009] Furthermore, the curing agent includes dicyandiamide, and the mass ratio of dicyandiamide to phenol-aralkyl type curing agent is (2.0~3.0):1; the curing accelerator is 2-methylimidazole.

[0010] A method for preparing an aralkyl epoxy resin adhesive for copper clad laminates, the specific preparation steps are as follows:

[0011] Step 1: Weigh out epoxy resin, phenol-aryl epoxy resin, glycine, molybdenum disulfide powder, CA-DDS charring agent, DOPO, hexachlorocyclotriphosphazene (HCCP), 2,2'-dihydroxybiphenyl, p-hydroxybenzaldehyde, 2-methylimidazole and dicyandiamide solution. The solid content of the dicyandiamide solution is 10.3-10.7%.

[0012] Step 2: Add glycine to deionized water and sonicate for 20-30 minutes to obtain a glycine solution. Divide the glycine solution into seven portions, take one portion and name it glycine solution a, and the remaining six portions and name it glycine solution b. Add molybdenum disulfide powder to glycine solution b, stir and treat for 23-25 ​​hours, then sonicate in a water bath for 11-13 hours, then centrifuge, remove the supernatant, add glycine solution a, and sonicate in a water bath for 5.5-6.5 hours. Then centrifuge, wash, centrifuge again, and dry to obtain nanofiller toughening agent-functionalized molybdenum disulfide nanosheets.

[0013] Step 3: Add hexachlorocyclotriphosphazene (HCCP) and 2,2'-dihydroxybiphenyl to an organic solvent and react in an ice-water bath at 0°C for 1.5–2.5 h. Then add p-hydroxybenzaldehyde solution and heat under reflux for 35–37 h. Then perform rotary evaporation and wash the precipitated solid with deionized water and ethanol to obtain intermediate product a. Add intermediate product a and DOPO to DMF solvent and heat for 23–25 h. Place the reaction solution in an ice-water bath to precipitate crystallization to obtain the flame retardant. Mix and grind the flame retardant and CA-DDS charring agent to obtain a composite flame retardant.

[0014] Step 4: Add the nanofiller toughening agent - functionalized molybdenum disulfide nanosheets to an organic solvent and sonicate for 10-20 minutes to obtain a suspension; add epoxy resin, phenol-aryl epoxy resin and composite flame retardant to a three-roll mill for grinding to obtain a mixture;

[0015] Step 5: Add the suspension, mixture, 2-methylimidazole and dicyandiamide solution to a vacuum mixer and stir to obtain an aralkyl epoxy resin solution for copper clad laminates.

[0016] Furthermore, in step two, the mass ratio of glycine to deionized water is 1:(6-8); the ultrasonic treatment power during glycine solution preparation is 400-600W, and the frequency is 1.4-1.6MHz; the stirring speed is 400-600r / min; the water bath ultrasonic temperature is 40-60℃, the water bath ultrasonic treatment power is 400-600W, and the water bath ultrasonic frequency is 40-60KHz; the centrifugation speed before adding glycine solution a is 1400-1600r / min, and the centrifugation time is 80-100min; the centrifugation speed after adding glycine solution a is 9500-10500r / min, and the centrifugation time is 50-70min; the washing step uses deionized water for washing.

[0017] Furthermore, in step three, the mass ratio of hexachlorocyclotriphosphazene (HCCP) to the organic solvent is 1:(6-8); the p-hydroxybenzaldehyde solution is a compound of p-hydroxybenzaldehyde and the organic solvent at a mass ratio of 1:(6-8); the reflux temperature is 50-60°C; the mass ratio of DOPO to DMF solvent is 1:(6-8); and the reaction temperature is 135-145°C; in steps three and four, the organic solvent is one of acetone, butanone, and N,N'-dimethylformamide (DMF).

[0018] Furthermore, in step four, the mass ratio of the nanofiller toughening agent-functionalized molybdenum disulfide nanosheets to the organic solvent is 1:(10-15), the ultrasonic treatment power is 400-600W, and the frequency is 1.4-1.6MHz; in step five, the stirring speed is 1600-2000r / min, and the stirring time is 3-5min.

[0019] Furthermore, in step two, the mass ratio of glycine to deionized water is 1:7; the ultrasonic treatment power during glycine solution preparation is 500W, and the frequency is 1.5MHz; the stirring speed is 500r / min; the water bath ultrasonic temperature is 50℃, the water bath ultrasonic treatment power is 500W, and the water bath ultrasonic frequency is 50KHz; the centrifugation speed before adding glycine solution a is 1500r / min, and the centrifugation time is 90min; the centrifugation speed after adding glycine solution a is 1000r / min, and the centrifugation time is 60min; in step three, hexachlorocyclotriphosphazene... The mass ratio of HCCP to organic solvent is 1:7; the p-hydroxybenzaldehyde solution is a mixture of p-hydroxybenzaldehyde and organic solvent at a mass ratio of 1:7; the mass ratio of DOPO to DMF solvent is 1:7, and the heating reaction temperature is 140℃; in steps three and four, the organic solvent is acetone; in step four, the mass ratio of nanofiller toughening agent-functionalized molybdenum disulfide nanosheets to organic solvent is 1:12, the ultrasonic treatment power is 500W, and the frequency is 1.5MHz; in step five, the stirring speed is 1800r / min, and the stirring time is 4min.

[0020] The technical effects and advantages of this invention are as follows:

[0021] 1. The aralkyl epoxy resin adhesive for copper-clad laminates prepared in this invention, when the toughening agent is at a low doping level (0.75-1.05%), can effectively improve the tensile strength and flexural strength of the cured copper-clad laminate, effectively improve the toughness of the copper-clad laminate, and thus effectively improve the safety of the copper-clad laminate; when the flame retardant is at a low doping level (5.5-6.5%), it can effectively improve the flame retardant performance of the cured copper-clad laminate; this results in relatively low doping levels of both toughening agent and flame retardant in the epoxy resin adhesive for copper-clad laminates, facilitating the addition of other functional raw materials to the epoxy resin adhesive, allowing for multifunctional adjustments of the copper-clad laminate adhesive without concern for the toughness and flame retardancy of the copper-clad laminate; glycine is used as an amino functionalizing agent. Functionalized molybdenum disulfide nanosheets were prepared using a liquid-phase exfoliation intercalation method. These functionalized nanosheets exhibited more uniform dispersion in the epoxy resin matrix. Higher nanosheet dispersion resulted in a greater free volume occupied within the resin matrix, leading to diverse and synergistic mechanisms that hindered crack propagation. Stronger interactions between the nanosheets and the matrix resulted in greater crack resistance and interfacial resistance around the nanosheets, leading to a better overall improvement in the toughness of the composite material. The composite flame retardant demonstrated synergistic flame retardant effects and high-efficiency flame retardant performance with low addition levels. It effectively reduced the combustion rate of the material and the flame propagation speed, exhibiting excellent flame retardant properties. Furthermore, the compounded flame retardant effectively promoted char formation.

[0022] 2. In this invention, glycine is dissolved in deionized water and subjected to ultrasonic treatment to ensure complete dissolution; molybdenum disulfide powder is added to glycine solution b and stirred to ensure thorough mixing; ultrasonic treatment in a water bath is performed to promote the exfoliation of molybdenum disulfide; centrifugation is then performed to separate unexfoliated molybdenum disulfide; after removing the supernatant, glycine solution a is added and ultrasonic treatment in a water bath is performed again to further improve the modification effect; then centrifugation, washing, further centrifugation, and drying are performed to finally obtain glycine-modified molybdenum disulfide powder; hexachlorocyclotriphosphazene (HCCP), 2,2'-dihydroxybiphenyl, and acetone are mixed and reacted in an ice-water bath at 0°C, and then p-hydroxybenzaldehyde solution is added and the mixture is heated to reflux for further reaction. Subsequently, the reaction solution was rotary evaporated, and the precipitated solid was washed with deionized water and ethanol to obtain intermediate product a. Intermediate product a and DOPO were added to DMF solvent and heated for reaction treatment. The reaction solution was placed in an ice-water bath for precipitation and crystallization to obtain flame retardant DBCP. Flame retardant DBCP and CA-DDS charring agent were mixed and ground to obtain composite flame retardant. Functionalized molybdenum disulfide nanosheets were added to acetone and ultrasonically treated to obtain suspension. Epoxy resin, phenol-aryl epoxy resin and composite flame retardant were added to a three-roll mill for grinding to obtain mixture. The suspension, mixture, phenol-aryl curing agent and dicyandiamide solution were stirred to obtain aryl epoxy resin adhesive for copper clad laminate. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1:

[0025] This invention provides an aralkyl epoxy resin adhesive for copper clad laminates, wherein the raw materials comprise by weight percentage: 0.75% nano-filler toughening agent, 5.5% composite flame retardant, 22% dicyandiamide, 1.8% 2-methylimidazole, and 69.95% composite epoxy resin.

[0026] The nanofiller toughening agent is functionalized molybdenum disulfide nanosheets, and the raw materials of the functionalized molybdenum disulfide nanosheets include glycine and molybdenum disulfide, and the mass ratio of glycine to molybdenum disulfide is 15:1.

[0027] The composite flame retardant comprises a flame retardant and a CA-DDS charring agent, wherein the mass ratio of the flame retardant to the CA-DDS charring agent is 6:4; the raw materials of the flame retardant include intermediate product a and DOPO, wherein the molar ratio of intermediate product a to DOPO is 1:1.9; the raw materials of intermediate product a include hexachlorocyclotriphosphazene (HCCP), 2,2'-dihydroxybiphenyl and p-hydroxybenzaldehyde, wherein the molar ratio of hexachlorocyclotriphosphazene (HCCP), 2,2'-dihydroxybiphenyl and p-hydroxybenzaldehyde is 1:2.0:2.0;

[0028] The composite epoxy resin includes epoxy resin and phenol-aryl type epoxy resin, and the mass ratio of the epoxy resin and phenol-aryl type epoxy resin is 2.0:1.

[0029] A method for preparing an aralkyl epoxy resin adhesive for copper clad laminates, the specific preparation steps are as follows:

[0030] Step 1: Weigh out epoxy resin, phenol-aryl epoxy resin, glycine, molybdenum disulfide powder, CA-DDS charring agent, DOPO, hexachlorocyclotriphosphazene (HCCP), 2,2'-dihydroxybiphenyl, p-hydroxybenzaldehyde, 2-methylimidazole and dicyandiamide solution. The solid content of the dicyandiamide solution is 10.3-10.7%.

[0031] Step 2: Glycine was added to deionized water and ultrasonically treated for 25 min (the mass ratio of glycine to deionized water was 1:6, the ultrasonic power was 400W, and the frequency was 1.4MHz) to obtain a glycine solution. The glycine solution was divided into seven portions, one portion was named glycine solution a, and the remaining six portions were named glycine solution b. Molybdenum disulfide powder was added to glycine solution b and stirred for 24 h (400 r / min). Then, it was ultrasonically treated in a water bath for 12 h (40℃, ultrasonic power was 400W, ultrasonic frequency was 40KHz). Then, it was centrifuged (centrifugation speed was 1400 r / min, centrifugation time was 80 min). After removing the supernatant, glycine solution a was added, and it was ultrasonically treated in a water bath for 6.0 h. Then, it was centrifuged, washed with deionized water, centrifuged again, and dried (centrifugation speed was 9500 r / min, centrifugation time was 50 min) to obtain nanofiller toughening agent-functionalized molybdenum disulfide nanosheets.

[0032] Step 3: Hexachlorocyclotriphosphazene (HCCP) and 2,2'-dihydroxybiphenyl were added to acetone (HCCP to acetone mass ratio 1:6), and reacted in an ice-water bath at 0°C for 2.0 h. Then, p-hydroxybenzaldehyde solution (p-hydroxybenzaldehyde and acetone were mixed in a mass ratio of 1:6) was added, and the mixture was heated (56°C) under reflux for 36 h. The solid was then removed by rotary evaporation and washed with deionized water and ethanol to obtain intermediate product a. Intermediate product a and DOPO were added to DMF solvent (DOPO to DMF solvent mass ratio 1:7), and the mixture was heated (135°C) for 24 h. The reaction solution was then placed in an ice-water bath for crystallization to obtain the flame retardant. The flame retardant and CA-DDS charring agent were mixed and ground to obtain a composite flame retardant.

[0033] Step 4: Add the nanofiller toughening agent - functionalized molybdenum disulfide nanosheets to acetone (the mass ratio of nanofiller toughening agent - functionalized molybdenum disulfide nanosheets to acetone is 1:10), and sonicate for 15 minutes (power is 400W, frequency is 1.4MHz) to obtain a suspension; add epoxy resin, phenol-aryl epoxy resin and composite flame retardant to a three-roll mill for grinding to obtain a mixture;

[0034] Step 5: Add the suspension, mixture, 2-methylimidazole and dicyandiamide solution to a vacuum mixer and stir (stirring speed 1600 r / min, stirring time 3 min) to obtain aralkyl epoxy resin adhesive for copper clad laminate.

[0035] Example 2:

[0036] Unlike Example 1, an aralkyl epoxy resin adhesive for copper clad laminates comprises, by weight percentage: 1.05% nanofiller toughening agent, 6.5% composite flame retardant, 24% dicyandiamide, 2.2% 2-methylimidazole, and 66.25% composite epoxy resin; the mass ratio of glycine to molybdenum disulfide is 20:1; the molar ratio of intermediate product a to DOPO is 1:2.1; the molar ratio of hexachlorocyclotriphosphazene (HCCP), 2,2'-dihydroxybiphenyl, and p-hydroxybenzaldehyde is 1:2.4:2.2; the mass ratio of epoxy resin to phenol-aralkyl type epoxy resin is 3.0:1; and the mass ratio of dicyandiamide to phenol-aralkyl resin is 3.0:1.

[0037] Example 3:

[0038] Unlike Example 1, an aralkyl epoxy resin adhesive for copper clad laminates comprises, by weight percentage: 0.90% nanofiller toughening agent, 6.0% composite flame retardant, 23% dicyandiamide, 2.0% 2-methylimidazole, and 68.1% composite epoxy resin; the mass ratio of glycine to molybdenum disulfide is 17.5:1; the molar ratio of intermediate product a to DOPO is 1:2.0; the molar ratio of hexachlorocyclotriphosphazene (HCCP), 2,2'-dihydroxybiphenyl, and p-hydroxybenzaldehyde is 1:2.2:2.1; the mass ratio of epoxy resin to phenol-aralkyl epoxy resin is 2.5:1; and the mass ratio of dicyandiamide to phenol-aralkyl resin is 2.5:1.

[0039] Example 4:

[0040] Unlike Example 3, in step two, the mass ratio of glycine to deionized water was 1:8; the ultrasonic treatment power during glycine solution preparation was 600W, and the frequency was 1.6MHz; the stirring speed was 600r / min; the water bath ultrasonic temperature was 60℃, the water bath ultrasonic treatment power was 600W, and the water bath ultrasonic frequency was 60KHz; the centrifugation speed before adding glycine solution a was 1600r / min, and the centrifugation time was 100min; the centrifugation speed after adding glycine solution a was 10500r / min, and the centrifugation time was 70min; the washing step used deionized water; in step three, hexachlorocyclotriphosphazene (… The mass ratio of HCCP to organic solvent is 1:8; the p-hydroxybenzaldehyde solution is a mixture of p-hydroxybenzaldehyde and organic solvent at a mass ratio of 1:8; the mass ratio of DOPO to DMF solvent is 1:8, and the heating reaction temperature is 145℃; in steps three and four, the organic solvent is one of acetone, butanone, and N,N'-dimethylformamide (DMF); in step four, the mass ratio of nanofiller toughening agent-functionalized molybdenum disulfide nanosheets to organic solvent is 1:15, the ultrasonic treatment power is 600W, and the frequency is 1.6MHz; in step five, the stirring speed is 2000r / min, and the stirring time is 5min.

[0041] Example 5:

[0042] Unlike Example 3, in step two, the mass ratio of glycine to deionized water was 1:7; the ultrasonic treatment power during glycine solution preparation was 500W, and the frequency was 1.5MHz; the stirring speed was 500r / min; the water bath ultrasonic temperature was 50℃, the water bath ultrasonic treatment power was 500W, and the water bath ultrasonic frequency was 50KHz; the centrifugation speed before adding glycine solution a was 1500r / min, and the centrifugation time was 90min; the centrifugation speed after adding glycine solution a was 1000r / min, and the centrifugation time was 60min; in step three, hexachlorocyclohexane... The mass ratio of triphosphazene (HCCP) to organic solvent is 1:7; the p-hydroxybenzaldehyde solution is a mixture of p-hydroxybenzaldehyde and organic solvent at a mass ratio of 1:7; the mass ratio of DOPO to DMF solvent is 1:7, and the heating reaction temperature is 140℃; in steps three and four, the organic solvent is acetone; in step four, the mass ratio of nanofiller toughening agent-functionalized molybdenum disulfide nanosheets to organic solvent is 1:12, the ultrasonic treatment power is 500W, and the frequency is 1.5MHz; in step five, the stirring speed is 1800r / min, and the stirring time is 4min.

[0043] Comparative Example 1:

[0044] Unlike Example 3, an aralkyl epoxy resin adhesive for copper clad laminates comprises, by weight percentage: 0.90% molybdenum disulfide nanosheets, 6.0% composite flame retardant, 23% dicyandiamide, 2.0% 2-methylimidazole, and 68.1% composite epoxy resin.

[0045] Comparative Example 2:

[0046] Unlike Example 3, an aralkyl epoxy resin adhesive for copper clad laminates comprises, by weight percentage: 0.90% nanofiller toughening agent, 6.0% composite flame retardant, 23% dicyandiamide, 2.0% 2-methylimidazole, and 68.1% composite epoxy resin; the composite flame retardant comprises a flame retardant and a CA-DDS charring agent, wherein the mass ratio of the flame retardant to the CA-DDS charring agent is 5:5.

[0047] Comparative Example 3:

[0048] Unlike Example 3, an aralkyl epoxy resin adhesive for copper clad laminates comprises, by weight percentage: 0.90% nanofiller toughening agent, 5.0% composite flame retardant, 23% dicyandiamide, 2.0% 2-methylimidazole, and 69.1% composite epoxy resin; the composite flame retardant comprises a flame retardant and a CA-DDS charring agent, wherein the mass ratio of the flame retardant to the CA-DDS charring agent is 6:4.

[0049] Of the above raw materials, the epoxy resin was purchased from Xingchen Synthetic Materials Co., Ltd. as bisphenol A-based epoxy resin (E-51, epoxy value 0.54); the phenol-aralkyl type epoxy resin was purchased from Hubei Maidehao Biotechnology Co., Ltd., with an effective ingredient content of 99%; the glycine was purchased from Sinopharm Chemical Reagent Co., Ltd., Sinopharm No.: 62011516; the molybdenum disulfide powder was purchased from Sinopharm Chemical Reagent Co., Ltd., Sinopharm No.: 20028560; the CA-DDS charring agent was prepared according to the literature (Zhang Tao, Du Zhongjie, Zou Wei, et al. Effect of ammonium polyphosphate / triazine charring agent / carbon nanotube composite system on flame retardancy of polypropylene [J]. Plastics, 2013, 42: 1-4); D OPO was purchased from Hubei Yongkuo Technology Co., Ltd., specifically 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), catalog number: YK3831; hexachlorocyclotriphosphazene (HCCP) was purchased from Wuhan Shuer Biotechnology Co., Ltd., purity: 99%; 2,2'-dihydroxybiphenyl was purchased from Sinopharm Chemical Reagent Co., Ltd., national drug number: LA14800100G; p-hydroxybenzaldehyde was purchased from Hubei Yongkuo Technology Co., Ltd., purity: 99%; 2-methylimidazole was purchased from Sinopharm Chemical Reagent Co., Ltd., national drug number: XW069398121; and dicyandiamide was purchased from Hubei Maidehao Biotechnology Co., Ltd., with an active ingredient content of 99%.

[0050] Performance test experiment of aralkyl epoxy resin adhesive for copper clad laminate: The performance of the aralkyl epoxy resin adhesive for copper clad laminate in the examples and comparative examples was tested: the aralkyl epoxy resin adhesive for copper clad laminate was poured into a mold, pre-cured at 160°C for 2 hours, then cured at 180°C for 2 hours, and cooled to room temperature to obtain the test sample.

[0051] Limiting Oxygen Index (LOI) Test: According to standard ISO4589-2:2006, the sample size is 130mm × 6.5mm × 3mm;

[0052] Vertical burning test: According to standard ANSI / UL94-2013, the sample size is 130mm×13mm×3.2mm;

[0053] Tensile strength: Tested according to ISO 527 standard, at a test speed of 50 mm / min;

[0054] Bending strength: Tested according to ISO 178 standard, at a test speed of 2 mm / min;

[0055] The results are shown in Table 1:

[0056] Table 1:

[0057]

[0058] The aralkyl epoxy resin adhesive for copper clad laminates in this invention, when the toughening agent is at a low doping level (0.75-1.05%), can effectively improve the tensile strength and flexural strength of the cured copper clad laminate, effectively improve the toughness of the copper clad laminate, and thus effectively improve the safety of the copper clad laminate; when the flame retardant is at a low doping level (5.5-6.5%), it can effectively improve the flame retardant performance of the cured copper clad laminate; this results in relatively low doping levels of both toughening agent and flame retardant in the epoxy resin adhesive for copper clad laminates, making it easy to add other functional raw materials to the epoxy resin adhesive, allowing for multi-functional adjustments to the copper clad laminate adhesive without worrying about the toughness and flame retardancy of the copper clad laminate;

[0059] This invention uses glycine as an amino functionalizing agent and employs a liquid-phase exfoliation intercalation method to prepare functionalized molybdenum disulfide nanosheets. The functionalized molybdenum disulfide nanosheets exhibit more uniform dispersion in the epoxy resin matrix. Because the modified molybdenum disulfide nanosheets are thinner in the longitudinal dimension, they are easier to disperse. Furthermore, the amino group in the glycine modifier acts as a bridge between the nanosheets and the epoxy resin, effectively locking the spatial position of the nanosheets in the epoxy resin matrix to counteract interlayer van der Waals forces. A good cross-linking effect is also one of the necessary conditions for enhancing the toughness of the composite material. Several mechanisms contribute to the improvement of the mechanical properties of nanoparticle-filled epoxy composites. The effects of crack bending, crack bridging, and matrix plastic deformation are considered. At lower doping levels (0.75–1.05%), the uniform dispersion of functionalized molybdenum disulfide nanosheets within the epoxy resin matrix, the interaction forces between the nanosheet surface and the resin matrix, and the continuous improvement in the toughness of the copper-clad laminate cured sheet are closely related. The higher the nanosheet dispersion, the more free volume it occupies in the resin matrix, and the more diverse and synergistic the ways in which crack propagation is hindered. The greater the interaction force between the nanosheet and the matrix, the stronger the crack resistance and interfacial resistance around the nanosheet, and the better the toughness improvement effect of the composite material on a macroscopic scale.

[0060] This invention synthesizes a DOPO-based cyclotriphosphazene macromolecular flame retardant—bis(DOPO-hydroxymethyl-phenoxy)-bis(2,2'-dihydroxybiphenyl)cyclotriphosphazene (DBCP). DBCP is then compounded with a charring agent (hydroxyethylaminotriazine-co-4,4'-diaminodiphenyl sulfone, CA-DDS) for flame retardancy in epoxy resins (EP). The combination of the DOPO-based cyclotriphosphazene macromolecular flame retardant (DBCP) and the CA-DDS charring agent exhibits synergistic flame retardant effects. It features high-efficiency flame retardancy with low additive content; 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) is a phosphorus-based flame retardant with high gas-phase flame retardancy efficiency; the composite flame retardant can effectively reduce the burning rate of materials and the flame propagation speed, exhibiting good flame retardant properties, and the compounded flame retardant has a good char-forming promoting effect; the degradation products of the nitrogen-sulfur homologous CA-DDS char-forming agent remain in large quantities in the char layer, increasing the N atom fraction in the char layer of the example to 3. The carbonization of the char layer increased significantly, and the P atomic fraction in the char layer also increased significantly. The char-forming agent CA-DDS promoted the cross-linking and carbonization of DBCP degradation products in the condensed phase, increasing the degree of cross-linking and significantly increasing the content of flame-retardant elements N, P, and S in the char layer. The increase in char layer mass and flame-retardant elements enhanced the flame-retardant effect of the condensed phase. The significant increase in the content of two important flame-retardant elements, N and P, in the condensed phase effectively improved the high thermal stability and flame-retardant performance of the char layer. Therefore, the combination of flame retardant and CA-DDS in the condensed phase has a synergistic flame-retardant effect. The production of non-flammable gas NH3 increased significantly. The composite flame retardant changed the structure and production of the thermal degradation products of epoxy resin, effectively reducing the amount of flammable degradation products, indicating a good gas-phase flame-retardant effect. The introduction of the char-forming agent CA-DDS not only increased the amount of NH3 in the gas phase and enhanced the dilution effect, thus improving the gas-phase flame-retardant efficiency, but also significantly increased the content of flame-retardant elements N and P in the condensed phase, significantly enhancing the flame-retardant function of the char layer. Therefore, the composite flame retardant has a synergistic flame-retardant effect in both the gas and condensed phases.

[0061] In step two, glycine is dissolved in deionized water and ultrasonically treated to ensure complete dissolution. Molybdenum disulfide powder is added to glycine solution b and stirred to ensure thorough mixing. Ultrasonic treatment in a water bath is then performed to promote the exfoliation of molybdenum disulfide. Centrifugation is then performed to separate unexfoliated molybdenum disulfide. After removing the supernatant, glycine solution a is added, and ultrasonic treatment in a water bath is performed again to further improve the modification effect. Centrifugation, washing, further centrifugation, and drying are then performed to finally obtain glycine-modified molybdenum disulfide powder. In step three, hexachlorocyclotriphosphazene (HCCP), 2,2'-dihydroxybiphenyl, and acetone are mixed and reacted in an ice-water bath at 0°C. After adding p-hydroxybenzaldehyde solution, the mixture is heated under reflux. The reaction solution was rotary evaporated, and the precipitated solid was washed with deionized water and ethanol to obtain intermediate product a. Intermediate product a and DOPO were added to DMF solvent and heated for reaction treatment. The reaction solution was placed in an ice-water bath for precipitation and crystallization to obtain flame retardant DBCP. Flame retardant DBCP and CA-DDS charring agent were mixed and ground to obtain composite flame retardant. In step four, functionalized molybdenum disulfide nanosheets were added to acetone and ultrasonically treated to obtain suspension. Epoxy resin, phenol-aryl epoxy resin and composite flame retardant were added to a three-roll mill for grinding to obtain mixture. In step five, suspension, mixture, phenol-aryl curing agent and dicyandiamide solution were stirred to obtain aryl epoxy resin adhesive for copper clad laminate.

[0062] 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 foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An aralkyl epoxy resin glue solution for a copper clad plate, characterized by comprising: 1) an aralkyl epoxy resin; 2) a curing agent; 3) a solvent; and 4) a curing accelerator. The raw materials include, by weight percentage, 0.75-1.05% of the nano-filler toughening agent, 5.5-6.5% of the composite flame retardant, 22-24% of the curing agent, 1.8-2.2% of the curing accelerator, and the balance of the composite epoxy resin.

2. The aralkyl epoxy resin glue liquid for copper-clad plates according to claim 1, characterized in that: The nano-filler toughening agent is functionalized molybdenum disulfide nanosheet, and the raw materials of the functionalized molybdenum disulfide nanosheet include glycine and molybdenum disulfide, with a mass ratio of (15-20) :

1. 3.The aralkyl epoxy resin glue liquid for a copper-clad plate according to claim 1, characterized in that: The composite flame retardant includes a flame retardant and a CA-DDS char-forming agent, with a mass ratio of 6:4; the raw materials of the flame retardant include intermediate a and DOPO, with a molar ratio of 1:(1.9-2.1); the raw materials of the intermediate a include hexachlorocyclotriphosphazene (HCCP), 2,2'-dihydroxydiphenyl and p-hydroxybenzaldehyde, with a molar ratio of 1:(2.0-2.4):(2.0-2.2).

4. The aralkyl epoxy resin glue liquid for copper-clad plates according to claim 1, characterized in that: The composite epoxy resin includes an epoxy resin and a phenol-aralkyl type epoxy resin, with a mass ratio of (2.0-3.0) :

1.

5. The aralkyl epoxy resin glue liquid for copper-clad plates according to claim 4, characterized in that: The curing agent includes dicyandiamide, with a mass ratio of (2.0-3.0) : 1 to the phenol-aralkyl type curing agent; and the curing accelerator is 2-methylimidazole.

6. A preparation method of aralkyl epoxy resin glue solution for copper-clad plate, characterized in that: The specific preparation steps are as follows: Step one: weigh the epoxy resin, the phenol-aralkyl type epoxy resin, glycine, molybdenum disulfide powder, the CA-DDS char-forming agent, DOPO, hexachlorocyclotriphosphazene (HCCP), 2,2'-dihydroxydiphenyl, p-hydroxybenzaldehyde, 2-methylimidazole and dicyandiamide solution, with a solid content of 10.3-10.7%; Step two: ultrasonically treat glycine in deionized water for 20-30 min to obtain a glycine solution, divide the glycine solution into seven parts, take one part out and name it as glycine solution a, and name the remaining six parts as glycine solution b; add molybdenum disulfide powder to the glycine solution b, stir for 23-25 h, then perform water bath ultrasonic treatment for 11-13 h, and then perform centrifugal treatment, remove the supernatant, add the glycine solution a, perform water bath ultrasonic treatment for 5.5-6.5 h, and then perform centrifugal, washing, re-centrifugal and drying treatments to obtain the nano-filler toughening agent, i.e., the functionalized molybdenum disulfide nanosheet. Step 3: Add hexachlorocyclotriphosphazene (HCCP) and 2,2'-dihydroxybiphenyl to an organic solvent and react in an ice-water bath at 0°C for 1.5–2.5 h. Then add p-hydroxybenzaldehyde solution and heat under reflux for 35–37 h. Then perform rotary evaporation and wash the precipitated solid with deionized water and ethanol to obtain intermediate product a. Add intermediate product a and DOPO to DMF solvent and heat for 23–25 h. Place the reaction solution in an ice-water bath to precipitate crystallization to obtain the flame retardant. Mix and grind the flame retardant and CA-DDS charring agent to obtain a composite flame retardant. Step 4: Add the nanofiller toughening agent - functionalized molybdenum disulfide nanosheets to an organic solvent and sonicate for 10-20 minutes to obtain a suspension; add epoxy resin, phenol-aryl epoxy resin and composite flame retardant to a three-roll mill for grinding to obtain a mixture; Step 5: Add the suspension, mixture, 2-methylimidazole and dicyandiamide solution to a vacuum mixer and stir to obtain an aralkyl epoxy resin solution for copper clad laminates. 7.The preparation method of the aralkyl epoxy resin glue liquid for a copper-clad plate according to claim 6, characterized by comprising the following steps of: In step two, the mass ratio of glycine to deionized water is 1:(6-8). The ultrasonic treatment power during the preparation of the glycine solution is 400-600W, and the frequency is 1.4-1.6MHz. The stirring speed is 400-600r / min. The water bath ultrasonic temperature is 40-60℃, the water bath ultrasonic power is 400-600W, and the water bath ultrasonic frequency is 40-60KHz. The centrifugation speed before adding glycine solution a is 1400-1600r / min, and the centrifugation time is 80-100min. The centrifugation speed after adding glycine solution a is 9500-10500r / min, and the centrifugation time is 50-70min. Deionized water is used for washing. 8.The preparation method of the aralkyl epoxy resin glue liquid for a copper-clad plate according to claim 7, characterized by comprising the following steps of: In step three, the mass ratio of hexachlorocyclotriphosphazene (HCCP) to the organic solvent is 1:(6-8); the p-hydroxybenzaldehyde solution is a mixture of p-hydroxybenzaldehyde and the organic solvent at a mass ratio of 1:(6-8); the reflux temperature is 50-60°C; the mass ratio of DOPO to DMF solvent is 1:(6-8); and the reaction temperature is 135-145°C; in steps three and four, the organic solvent is one of acetone, butanone, and N,N'-dimethylformamide (DMF). 9.The preparation method of the aralkyl epoxy resin glue liquid for a copper-clad plate according to claim 8, characterized by comprising the following steps of: In step four, the mass ratio of the nanofiller toughening agent-functionalized molybdenum disulfide nanosheets to the organic solvent is 1:(10-15), the ultrasonic treatment power is 400-600W, and the frequency is 1.4-1.6MHz; in step five, the stirring speed is 1600-2000r / min, and the stirring time is 3-5min. 10.The preparation method of the aralkyl epoxy resin glue liquid for a copper-clad plate according to claim 9, characterized in that: In step two, the mass ratio of glycine to deionized water is 1:

7. The ultrasonic treatment power during the preparation of the glycine solution is 500W, and the frequency is 1.5MHz. The stirring speed is 500r / min. The water bath ultrasonic temperature is 50℃, the water bath ultrasonic treatment power is 500W, and the water bath ultrasonic frequency is 50KHz. The centrifugation speed before adding glycine solution a is 1500r / min, and the centrifugation time is 90min. The centrifugation speed after adding glycine solution a is 1000r / min, and the centrifugation time is 60min. In step three, hexachlorocyclotriphosphazene (HCCP) and... The mass ratio of the organic solvent to the organic solvent is 1:7; the p-hydroxybenzaldehyde solution is a mixture of p-hydroxybenzaldehyde and an organic solvent at a mass ratio of 1:7; the reflux temperature is 56°C; the mass ratio of DOPO to DMF solvent is 1:7, and the reaction temperature is 140°C; in steps three and four, the organic solvent is acetone; in step four, the mass ratio of the nanofiller toughening agent-functionalized molybdenum disulfide nanosheets to the organic solvent is 1:12, the ultrasonic treatment power is 500W, and the frequency is 1.5MHz; in step five, the stirring speed is 1800r / min, and the stirring time is 4min.

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