Resin glue solution for high-cti copper-clad plate and preparation method thereof

Abstract

This invention provides a resin adhesive for high CTI copper-clad laminates, made from the following raw materials in parts by weight: 100 parts brominated epoxy resin, 28-32 parts linear high ortho-phenolic resin curing agent, 10-14 parts flame retardant, 0.6-1 part accelerator, 1-2 parts leveling agent, 5-7 parts additives, and 42-46 parts solvent. This invention also provides a method for preparing this resin adhesive. The resin adhesive for high CTI copper-clad laminates provided by this invention uses a linear high ortho-phenolic resin curing agent, which can effectively improve the heat resistance, insulation performance, and CTI value of the copper-clad laminate.

Description

Technical Field

[0001] This invention relates to resin adhesives, and more particularly to a resin adhesive for high CTI copper clad laminates and its preparation method. Background Technology

[0002] Epoxy resin curing agents mainly include amines, phenols, acid anhydrides, and nitrogen-containing compounds. Among them, linear phenolic resin is a widely used thermosetting latent curing agent. Epoxy materials made using linear phenolic resin curing agents have advantages over those made using other curing agents, such as low CTE, low Df, good chemical resistance, and low curing shrinkage. However, using this curing agent also has drawbacks, including slow reaction speed, higher brittleness of the finished product, and higher hygroscopicity. Furthermore, the copper-clad laminate manufacturing industry places higher demands on the heat resistance and durability of materials, thus requiring modification of linear phenolic resin curing agents.

[0003] Linear phenolic resin is a thermoplastic phenolic resin formed by the condensation of phenol and formaldehyde under acidic conditions. Its molecular backbone is mainly –Ph-CH2-Ph-, with almost no or little hydroxymethyl (-CH2OH) content. Its molecules are linear or slightly branched, with a large number of phenolic hydroxyl groups and strong polarity. Mn is controllable, mostly between 500 and 3000. As a curing agent for epoxy resins, linear phenolic resin is the mainstay of high Tg and high heat resistance systems. However, it also has a series of structural and process defects in engineering applications. For example, the high hydroxyl density leads to low elongation at break and poor impact resistance of the finished product; the large number of phenolic hydroxyl groups makes copper-clad laminates prone to absorbing moisture, reducing Tg and increasing the risk of CAF; and the limited compatibility with flexible modified epoxy resins leads to uneven Tg distribution and local performance degradation, resulting in a low CTI value and insufficient durability of the finished copper-clad laminate. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a resin adhesive for high CTI copper clad laminates, which uses a linear high ortho-phenolic resin curing agent, and can effectively improve the heat resistance, insulation performance and CTI value of copper clad laminates.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A resin adhesive for high CTI copper clad laminates is made from the following raw materials in parts by weight: 100 parts of brominated epoxy resin, 28-32 parts of linear high ortho-phenolic resin curing agent, 10-14 parts of flame retardant, 0.6-1 parts of accelerator, 1-2 parts of leveling agent, 5-7 parts of additives, and 42-46 parts of solvent.

[0007] Furthermore, the brominated epoxy resin of the present invention is a brominated bisphenol A type epoxy resin with a bromine content of 20-25 wt%.

[0008] The linear high-ortho-phenolic resin curing agent used in this invention is based on high-purity phenol with a small amount of para-hindered phenol introduced to suppress the para-reaction. The aldehyde source is paraformaldehyde, and the phenol-formaldehyde molar ratio is controlled between 1:(0.80–0.85), favoring phenol enrichment to suppress branching and three-dimensional network formation. Zinc acetate and glacial acetic acid are used as catalysts. The target ortho-substitution degree is 67-75%, the target number-average molecular weight is 700-900, and the target free phenol content is <4.0%.

[0009] Specifically, the linear high-ortho-phenolic resin curing agent of the present invention is prepared by the following steps:

[0010] A1. Under nitrogen protection, add the phenolic raw material to the reactor and heat it to 50-70℃ to completely melt the phenolic raw material. Then, add the aldehyde raw material and catalyst to the reactor in batches (as the reaction proceeds, the viscosity of the system gradually increases, entering the main condensation stage). Heat it to 90-110℃ and react for 3.5-5 hours (during which the free phenol content, softening point and viscosity are monitored by sampling as criteria for molecular weight control) to obtain reaction solution one;

[0011] A2. Cool the reaction solution one obtained in step A1 to 85-88℃, add the neutralized liquid droplets to the reaction solution one, and keep it warm for 20-30 minutes after the addition is complete to obtain reaction solution two. After dehydrating reaction solution two, heat it to 90-95℃ and continue stirring for 30-60 minutes to obtain linear high ortho-phenolic resin curing agent.

[0012] Further, in step A1 of the preparation of the linear high-ortho-phenolic resin curing agent of the present invention, the phenolic raw material is composed of phenol and p-nonylphenol in a molar ratio of 19:1, the aldehyde raw material is paraformaldehyde, and the catalyst is composed of zinc acetate and glacial acetic acid. The molar ratio of phenolic raw material to paraformaldehyde is 1:(0.80-0.85), and the molar ratio of phenolic raw material, zinc acetate, and glacial acetic acid is 100:0.18:0.40. The aldehyde raw material and the catalyst are added to the reaction vessel in 3-4 portions, with an interval of 20-30 minutes between each addition. The pH value of the reaction system is 6-6.2, and the temperature is 72°C.

[0013] In step A2 of the preparation of the linear high-ortho-phenolic resin curing agent, the neutralizing solution is an 8% sodium acetate solution, the molar ratio of phenolic raw material to sodium acetate is 100:0.36, the addition time of the neutralizing solution is 25 minutes, and the pH value of the reaction system is 6.8-7.2; the dehydration process of the reaction solution is as follows: dehydration begins at 88-90℃ and normal pressure, the pressure is reduced to -0.04MPa in the first stage and maintained for 30 minutes, the pressure is reduced to -0.06 to -0.08MPa in the second stage and maintained for 30 minutes, and the temperature is 95℃.

[0014] Furthermore, the flame retardant described in this invention is decabromodiphenyl ethane.

[0015] Furthermore, the accelerator described in this invention is 2-ethyl-4-methylimidazole.

[0016] Furthermore, the leveling agent described in this invention is BYK-410.

[0017] Furthermore, the auxiliary agent described in this invention is 2-chloro-1-methylpyridine p-toluenesulfonate, and the solvent is propylene glycol methyl ether.

[0018] Another technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned resin solution for high CTI copper clad laminates.

[0019] To solve the above technical problems, the technical solution is as follows:

[0020] A method for preparing a resin adhesive for high CTI copper-clad laminates includes the following steps:

[0021] S1. Weigh each raw material according to the mass fraction, mix the curing agent, accelerator and solvent, and stir for 1-2 hours to obtain mixture one;

[0022] S2. Add the brominated epoxy resin to the first mixture obtained in step S1 and stir for 2-3 hours to obtain the second mixture.

[0023] S3. Add the other raw materials to the mixture obtained in step S2, stir for 3-4 hours, and let stand for 4-6 hours to obtain the resin solution for high CTI copper clad laminate.

[0024] Further, in step S1 of the present invention, the stirring speed is 800-1000 rpm; in step S2, the stirring speed is 1000-1200 rpm; and in step S3, the stirring speed is 1200-1500 rpm.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The curing agent used in this invention is a linear high ortho-phenolic epoxy curing agent, which can achieve a certain degree of crosslinking through the initial reaction with the epoxy resin blend system. After high-temperature curing, the epoxy resin in the blend system can be fully cured, increasing the degree of crosslinking of the system, thereby improving the overall system and the heat resistance, insulation performance and CTI value of the copper clad laminate.

[0027] (2) The linear high ortho-phenolic epoxy curing agent used in this invention is a reactive curing agent, which can improve the compatibility of the blend system, which is beneficial to the impregnation of the resin system into the paper substrate, and effectively improves the mechanical processing performance of the copper clad laminate; in addition, the additive used in this invention, 2-chloro-1-methylpyridine p-toluenesulfonate, can also effectively reduce the warpage of the copper clad laminate and improve the bonding force of the copper clad laminate. Detailed Implementation

[0028] The present invention will now be described in detail with reference to specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0029] Example 1

[0030] The resin adhesive used in high CTI copper-clad laminates is made from the following raw materials in parts by weight: 100 parts brominated epoxy resin, 30 parts linear high ortho-phenolic resin curing agent, 12 parts flame retardant, 0.8 parts accelerator, 1.5 parts leveling agent, 6 parts additives, and 44 parts solvent. The brominated epoxy resin is a brominated bisphenol A type epoxy resin with a bromine content of 24 wt%, the flame retardant is decabromodiphenyl ethane, the accelerator is 2-ethyl-4-methylimidazolium, the leveling agent is BYK-410, the additive is 2-chloro-1-methylpyridine p-toluenesulfonate, and the solvent is propylene glycol methyl ether.

[0031] The linear high-ortho-phenolic resin curing agent is prepared by the following steps:

[0032] A1. Under nitrogen protection, phenolic raw materials consisting of phenol and p-nonylphenol in a molar ratio of 19:1 are added to a reaction vessel. The temperature is raised to 60°C to completely melt the phenolic raw materials. Then, paraformaldehyde, zinc acetate, and glacial acetic acid are added to the reaction vessel in three portions (each 25 minutes apart, the pH of the reaction system is 6.1, and the temperature is 72°C). The temperature is raised to 100°C and reacted for 4 hours to obtain reaction solution one. In this solution, the molar ratio of phenolic raw materials to paraformaldehyde is 1:0.84, and the molar ratio of phenolic raw materials to zinc acetate and glacial acetic acid is 100:0.18:0.40.

[0033] A2. Cool the reaction solution one obtained in step A1 to 87°C, and add an 8% sodium acetate solution dropwise to the reaction solution one over 25 minutes (the pH of the reaction system is 7.0). The molar ratio of phenolic raw material to sodium acetate is 100:0.36. After the addition is completed, keep it warm for 25 minutes to obtain reaction solution two. After dehydrating reaction solution two, heat it to 93°C and continue stirring for 45 minutes to obtain a linear high-ortho-phenolic resin curing agent. The dehydration process of reaction solution two is as follows: dehydration begins at 89°C and normal pressure. In the first stage, the pressure is reduced to -0.04MPa and maintained for 30 minutes. In the second stage, the pressure is reduced to -0.07MPa and maintained for 30 minutes, and the temperature is 95°C.

[0034] The preparation method of Example 1 includes the following steps:

[0035] S1. Weigh each raw material according to the mass fraction, mix the curing agent, accelerator and solvent, and stir at 900 rpm for 1.5 hours to obtain mixture one;

[0036] S2. Add the brominated epoxy resin to the mixture obtained in step S1, and stir at 1100 rpm for 2.5 hours to obtain mixture two;

[0037] S3. Add the other raw materials to the mixture obtained in step S2, stir at 1400 rpm for 3.5 hours, and let stand for 5 hours to obtain the resin solution for high CTI copper clad laminate.

[0038] Example 2

[0039] The resin adhesive used in high CTI copper-clad laminates is made from the following raw materials in parts by weight: 100 parts brominated epoxy resin, 32 parts linear high ortho-phenolic resin curing agent, 14 parts flame retardant, 1 part accelerator, 2 parts leveling agent, 7 parts additives, and 46 parts solvent. The brominated epoxy resin is a brominated bisphenol A type epoxy resin with a bromine content of 25 wt%, the flame retardant is decabromodiphenyl ethane, the accelerator is 2-ethyl-4-methylimidazolium, the leveling agent is BYK-410, the additive is 2-chloro-1-methylpyridine p-toluenesulfonate, and the solvent is propylene glycol methyl ether.

[0040] The linear high-ortho-phenolic resin curing agent is prepared by the following steps:

[0041] A1. Under nitrogen protection, phenolic raw materials consisting of phenol and p-nonylphenol in a molar ratio of 19:1 are added to a reaction vessel. The temperature is raised to 70°C to completely melt the phenolic raw materials. Then, paraformaldehyde, zinc acetate, and glacial acetic acid are added to the reaction vessel in three portions (each 20 minutes apart, the pH of the reaction system is 6, and the temperature is 72°C). The temperature is raised to 110°C and the reaction is carried out for 3.5 hours to obtain reaction solution one. In this solution, the molar ratio of phenolic raw materials to paraformaldehyde is 1:0.85, and the molar ratio of phenolic raw materials to zinc acetate to glacial acetic acid is 100:0.18:0.40.

[0042] A2. Cool the reaction solution one obtained in step A1 to 88℃, and add an 8% sodium acetate solution dropwise to the reaction solution one over 25 minutes (the pH of the reaction system is 6.8). The molar ratio of phenolic raw material to sodium acetate is 100:0.36. After the addition is completed, keep it warm for 20 minutes to obtain reaction solution two. After dehydrating reaction solution two, heat it to 95℃ and continue stirring for 30 minutes to obtain linear high ortho-phenolic resin curing agent. The dehydration process of reaction solution two is as follows: dehydration begins at 90℃ and normal pressure. In the first stage, the pressure is reduced to -0.04MPa and maintained for 30 minutes. In the second stage, the pressure is reduced to -0.06MPa and maintained for 30 minutes, and the temperature is 95℃.

[0043] The preparation method of Example 2 includes the following steps:

[0044] S1. Weigh each raw material according to the mass fraction, mix the curing agent, accelerator and solvent, and stir at 1000 rpm for 1 hour to obtain the first mixture;

[0045] S2. Add the brominated epoxy resin to the first mixture obtained in step S1, and stir at 1200 rpm for 2 hours to obtain the second mixture;

[0046] S3. Add the other raw materials to the mixture obtained in step S2, stir at 1500 rpm for 3 hours, and let stand for 4 hours to obtain the resin solution for high CTI copper clad laminate.

[0047] Example 3

[0048] The resin adhesive used in high CTI copper-clad laminates is made from the following raw materials in parts by weight: 100 parts brominated epoxy resin, 28 parts linear high ortho-phenolic resin curing agent, 10 parts flame retardant, 0.6 parts accelerator, 1 part leveling agent, 5 parts additives, and 42 parts solvent. The brominated epoxy resin is a brominated bisphenol A type epoxy resin with a bromine content of 20 wt%, the flame retardant is decabromodiphenyl ethane, the accelerator is 2-ethyl-4-methylimidazolium, the leveling agent is BYK-410, the additive is 2-chloro-1-methylpyridine p-toluenesulfonate, and the solvent is propylene glycol methyl ether.

[0049] The linear high-ortho-phenolic resin curing agent is prepared by the following steps:

[0050] A1. Under nitrogen protection, phenolic raw materials composed of phenol and p-nonylphenol in a molar ratio of 19:1 are added to a reaction vessel. The temperature is raised to 50°C to completely melt the phenolic raw materials. Then, paraformaldehyde, zinc acetate, and glacial acetic acid are added to the reaction vessel in four portions (each 30 minutes apart, the pH of the reaction system is 6.2, and the temperature is 72°C). The temperature is raised to 90°C and the reaction is carried out for 5 hours to obtain reaction solution one. In this solution, the molar ratio of phenolic raw materials to paraformaldehyde is 1:0.80, and the molar ratio of phenolic raw materials to zinc acetate and glacial acetic acid is 100:0.18:0.40.

[0051] A2. Cool the reaction solution one obtained in step A1 to 85℃, and add an 8% sodium acetate solution dropwise to the reaction solution one over 25 minutes (the pH of the reaction system is 7.2). The molar ratio of phenolic raw material to sodium acetate is 100:0.36. After the addition is completed, keep it warm for 30 minutes to obtain reaction solution two. After dehydrating reaction solution two, heat it to 90℃ and continue stirring for 60 minutes to obtain linear high ortho-phenolic resin curing agent. The dehydration process of reaction solution two is as follows: dehydration begins at 88℃ and normal pressure. In the first stage, the pressure is reduced to -0.04MPa and maintained for 30 minutes. In the second stage, the pressure is reduced to -0.08MPa and maintained for 30 minutes, and the temperature is 95℃.

[0052] The preparation method of Example 3 includes the following steps:

[0053] S1. Weigh each raw material according to the mass fraction, mix the curing agent, accelerator and solvent, and stir at 800 rpm for 2 hours to obtain the first mixture;

[0054] S2. Add the brominated epoxy resin to the mixture obtained in step S1, and stir at 1000 rpm for 3 hours to obtain mixture two;

[0055] S3. Add the other raw materials to the mixture obtained in step S2, stir at 1200 rpm for 4 hours, and let stand for 6 hours to obtain the resin solution for high CTI copper clad laminate.

[0056] Comparative Example 1

[0057] The difference from Example 1 is that the linear high-ortho-phenolic resin curing agent in the raw materials is replaced with a common linear phenolic resin curing agent (purchased from Japan DIC Corporation, brand name TD-2131), and the preparation step of the linear high-ortho-phenolic resin curing agent is omitted.

[0058] Comparative Example 2

[0059] The difference from Example 1 is that the raw materials do not include the auxiliary agent 2-chloro-1-methylpyridine p-toluenesulfonate.

[0060] Experimental Example 1:

[0061] To manufacture copper-clad laminates, follow these steps:

[0062] (1) Immerse bleached wood pulp paper (126g / m²) in resin solution (prepared from Examples 1-3 and Comparative Examples 1-2), remove it after 30s, and then put it into an oven and bake at 170°C for 2 minutes to obtain a core material semi-cured sheet.

[0063] (2) The fiberglass cloth (type 7628) was immersed in the resin solution (prepared from Examples 1-3 and Comparative Examples 1-2), and after 30 seconds it was taken out and then put into the oven and baked at 170°C for 2 minutes to obtain a semi-cured sheet of the fabric.

[0064] (3) Take 5 core material semi-cured sheets obtained in step (1) and stack them together to obtain laminate one. Cover the upper and lower surfaces of laminate one with a fabric semi-cured sheet obtained in step (2) to obtain laminate two. Cover the upper surface of laminate two with a copper foil (thickness of 18μm, conforming to IPC-MF-150F standard) to obtain laminate three. Place laminate three between two stainless steel plates and send it into a laminator. Hot press at 170℃ and 20MPa pressure for 1.5 hours. After cooling to room temperature, obtain copper-clad laminate.

[0065] Experiment Example 2: Heat Resistance Test

[0066] Test reference standard / method: DSC method.

[0067] Test instrument: Differential scanning calorimeter.

[0068] Test object and target: Tg of the copper-clad laminate (Examples 1-3, Comparative Example 1) prepared by Experiment 1.

[0069] A higher Tg indicates better heat resistance. The test results are shown in Table 1.

[0070] Tg (°C) Example 1 193.3 Example 2 195.1 Example 3 191.8 Comparative Example 164.6

[0071] Table 1

[0072] As shown in Table 1, the heat resistance (Tg) of Examples 1-4 of this invention is relatively high, indicating that the resin adhesive prepared by this invention for high CTI copper-clad laminates can effectively improve the heat resistance of copper-clad laminates. Comparative Example 1 uses some different raw materials and preparation steps than Example 1. Compared with Example 1, the Tg of Comparative Example 1 is lower, indicating that the linear high-ortho-phenolic resin curing agent used in this invention can effectively improve the heat resistance of copper-clad laminates.

[0073] Experiment Example 3: Insulation Performance Test

[0074] Test reference standard / method: IPC-TM-650 standard.

[0075] Test instrument: High resistance meter.

[0076] Test object and target: The volume resistivity of the copper-clad laminate (Examples 1-3, Comparative Example 1) prepared by Experiment 1.

[0077] A higher volume resistivity indicates better insulation performance. The test results are shown in Table 2.

[0078] Volume resistivity (Ω·cm) Example 1 <![CDATA[1.2×10 14 <!-- 5 -->]]> Example 2 <![CDATA[1.3×10 14 ]]> Example 3 <![CDATA[1.1×10 14 ]]> Comparative Example 1 <![CDATA[8.6×10 13 ]]>

[0079] Table 2

[0080] As shown in Table 2, the volume resistivity of Examples 1-4 of the present invention is relatively high, indicating that the resin adhesive prepared by the present invention for high CTI copper-clad laminates can effectively improve the insulation performance of copper-clad laminates. Comparative Example 1 uses some different raw materials and preparation steps than Example 1. Compared with Example 1, the volume resistivity of Comparative Example 1 is lower, indicating that the linear high ortho-phenolic resin curing agent used in the present invention can effectively improve the insulation performance of copper-clad laminates.

[0081] Experiment Example 4: Leakage Resistance Test

[0082] Test reference standard / method: IEC60112-2009 standard.

[0083] Testing instrument: Tracking current tester.

[0084] Test object and target: CTI of copper-clad laminates (Examples 1-3, Comparative Example 1) prepared by Experiment 1.

[0085] A higher CTI indicates better leakage current resistance. The test results are shown in Table 3.

[0086] CTI(V) Example 1 650 Example 2 650 Example 3 650 Comparative Example 1 350

[0087] Table 3

[0088] As shown in Table 3, the CTI of Examples 1-4 of the present invention are all relatively high, indicating that the resin adhesive prepared by the present invention for high CTI copper-clad laminates can effectively improve the leakage current resistance of copper-clad laminates. Comparative Example 1 uses some different raw materials and preparation steps than Example 1. Compared with Example 1, the CTI of Comparative Example 1 is lower, indicating that the linear high-ortho-phenolic resin curing agent used in the present invention can effectively improve the leakage current resistance of copper-clad laminates.

[0089] Experiment Example 5: Water Resistance Test

[0090] Test reference standard / method: IPC-TM-650 standard.

[0091] Test object and target: The water absorption rate of the copper-clad laminate (Examples 1-3, Comparative Example 1) prepared by Experiment 1.

[0092] A lower water absorption rate indicates better water resistance. The test results are shown in Table 4.

[0093] Water absorption rate (%) Example 1 0.07 Example 2 0.06 Example 3 0.09 Comparative Example 1 0.12

[0094] Table 4

[0095] As shown in Table 4, the water absorption rates of Examples 1-4 of the present invention are all low, indicating that the resin adhesive prepared by the present invention for high CTI copper-clad laminates can effectively improve the water resistance of copper-clad laminates. Comparative Example 1 uses some different raw materials and preparation steps than Example 1. Compared with Example 1, the water absorption rate of Comparative Example 1 is higher, indicating that the linear high ortho-phenolic resin curing agent used in the present invention can effectively improve the water resistance of copper-clad laminates.

[0096] Experiment Example 6: Bonding Force Test

[0097] Test reference standard / method: IPC-TM-650 standard.

[0098] Testing instrument: Peel strength tester.

[0099] Test object and target: Peel strength of copper-clad laminates (Examples 1-3, Comparative Example 2) prepared by Experiment 1.

[0100] Higher peel strength indicates better adhesion. The test results are shown in Table 5.

[0101] Peel strength (KN / m) Example 1 1.54 Example 2 1.57 Example 3 1.52 Comparative Example 2 1.31

[0102] Table 5

[0103] As shown in Table 5, the peel strength of Examples 1-4 of the present invention is relatively high, indicating that the resin adhesive prepared by the present invention for high CTI copper-clad laminates can effectively improve the adhesion of the copper-clad laminates. Comparative Example 2 uses some different raw materials and preparation steps than Example 1. Compared with Example 1, the peel strength of Comparative Example 2 is lower, indicating that the additive used in the present invention—2-chloro-1-methylpyridine p-toluenesulfonate—can effectively improve the adhesion of the copper-clad laminate.

[0104] Experiment 7: Warp Test

[0105] Test reference standard / method: The copper-clad laminate is heated from room temperature to 260℃, and the deformation height and deformation height grade of the copper-clad laminate are measured: when the deformation height is ≤150μm, the deformation height grade is grade 1; when the deformation height is 150-350μm, the deformation height grade is grade 2; when the deformation height is 350-500μm, the deformation height grade is grade 3; when the deformation height is ≥500μm, the deformation height grade is grade 4.

[0106] Test object and target: The deformation height level of the copper-clad laminate (Examples 1-3, Comparative Example 2) prepared by Experiment 1.

[0107] A lower deformation height grade indicates lower warpage. The test results are shown in Table 6.

[0108] Deformation height level Example 1 Level 1 Example 2 Level 1 Example 3 Level 1 Comparative Example 2 Level 2

[0109] Table 6

[0110] As shown in Table 6, the deformation height grades of Examples 1-4 of the present invention are all Grade 1, indicating that the resin adhesive prepared by the present invention for high CTI copper-clad laminates can effectively reduce the warpage of the copper-clad laminates. Comparative Example 2 uses some different raw materials and preparation steps than Example 1. Compared with Example 1, the deformation height grade of Comparative Example 2 is higher, indicating that the additive used in the present invention—2-chloro-1-methylpyridine p-toluenesulfonate—can effectively reduce the warpage of the copper-clad laminate.

[0111] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A resin glue solution for high CTI copper-clad plate, characterized in that: It is made from the following raw materials in parts by weight: 100 parts of brominated epoxy resin, 28-32 parts of linear high ortho-phenolic resin curing agent, 10-14 parts of flame retardant, 0.6-1 parts of accelerator, 1-2 parts of leveling agent, 5-7 parts of additives, and 42-46 parts of solvent. ​ 2. The resin glue solution for high-CTI copper-clad plates according to claim 1, characterized in that: The brominated epoxy resin is a brominated bisphenol A type epoxy resin with a bromine content of 20-25 wt%.

3. The resin glue solution for high-CTI copper-clad plates according to claim 1, characterized in that: The linear high-ortho-phenolic resin curing agent is prepared by the following steps: A1. Under nitrogen protection, add phenol raw material to the reactor, heat to 50-70℃ to completely melt the phenol raw material, then add aldehyde raw material and catalyst to the reactor in batches, heat to 90-110℃ and react for 3.5-5 hours to obtain reaction solution one; A2. Cool the reaction solution one obtained in step A1 to 85-88℃, add the neutralized liquid droplets to the reaction solution one, and keep it warm for 20-30 minutes after the addition is complete to obtain reaction solution two. After dehydrating reaction solution two, heat it to 90-95℃ and continue stirring for 30-60 minutes to obtain linear high ortho-phenolic resin curing agent.

4. The resin glue solution for high-CTI copper-clad plates according to claim 3, characterized in that: In step A1 of the preparation of the linear high-ortho-phenolic resin curing agent, the phenolic raw material is composed of phenol and p-nonylphenol in a molar ratio of 19:1, the aldehyde raw material is paraformaldehyde, and the catalyst is composed of zinc acetate and glacial acetic acid. The molar ratio of phenolic raw material to paraformaldehyde is 1:(0.80-0.85), and the molar ratio of phenolic raw material, zinc acetate, and glacial acetic acid is 100:0.18:0.

40. The aldehyde raw material and catalyst are added to the reaction vessel in 3-4 batches, with an interval of 20-30 minutes between each batch. The pH value of the reaction system is 6-6.2, and the temperature is 72℃. In step A2 of the preparation of the linear high-ortho-phenolic resin curing agent, the neutralizing solution is an 8% sodium acetate solution, the molar ratio of phenolic raw material to sodium acetate is 100:0.36, the addition time of the neutralizing solution is 25 minutes, and the pH value of the reaction system is 6.8-7.2; the dehydration process of the reaction solution is as follows: dehydration begins at 88-90℃ and normal pressure, the pressure is reduced to -0.04MPa in the first stage and maintained for 30 minutes, the pressure is reduced to -0.06 to -0.08MPa in the second stage and maintained for 30 minutes, and the temperature is 95℃.

5. The resin glue solution for high-CTI copper-clad plates according to claim 1, characterized in that: The flame retardant is decabromodiphenyl ethane.

6. The resin glue solution for high-CTI copper-clad plates according to claim 1, characterized in that: The accelerator is 2-ethyl-4-methylimidazole.

7. The resin adhesive for high CTI copper-clad laminates according to claim 1, characterized in that: The leveling agent is BYK-410.

8. The resin adhesive for high CTI copper-clad laminates according to claim 1, characterized in that: The auxiliary agent is 2-chloro-1-methylpyridine p-toluenesulfonate, and the solvent is propylene glycol methyl ether.

9. A method for preparing a resin adhesive for high CTI copper-clad laminates according to any one of claims 1 to 8, characterized in that: Includes the following steps: S1. Weigh each raw material according to the mass fraction, mix the curing agent, accelerator and solvent, and stir for 1-2 hours to obtain mixture one; S2. Add the brominated epoxy resin to the first mixture obtained in step S1 and stir for 2-3 hours to obtain the second mixture. S3. Add the other raw materials to the mixture obtained in step S2, stir for 3-4 hours, and let stand for 4-6 hours to obtain the resin solution for high CTI copper clad laminate.

10. A method for preparing a resin adhesive for high CTI copper-clad laminates according to claim 9, characterized in that: In step S1, the stirring speed is 800-1000 rpm; in step S2, the stirring speed is 1000-1200 rpm; and in step S3, the stirring speed is 1200-1500 rpm.