Halogen-free paper-based adhesive and manufacturing method of halogen-free paper-based copper clad laminate

Abstract

The application discloses a halogen-free paper-based glue and a manufacturing method of a halogen-free composite paper-based copper-clad plate, relates to the technical fields of flame-retardant composite and copper-clad plate, and comprises the following steps: S100, epoxy resin modified nitrogen-phosphorus phenolic resin; S201, tung oil modified phenolic resin; S301, halogen-free paper-based glue; S302, preparation of a halogen-free paper-based prepreg; S303, halogen-free cloth-based glue; S304, preparation of a cloth-based prepreg; and S305, preparation of a halogen-free composite paper-based copper-clad plate. The prepared product uses linear phenolic resin as an epoxy resin curing agent, is cross-linked to form a net-like three-dimensional structure, the main body is provided with P-N flame-retardant synergistic effect to increase the flame-retardant effect, and the vertical burning grade effect of the plate is improved to reach FV-0 level. In the case that the performance and manufacturing process of a PCB circuit board are not affected, the halogen-free paper-based flame-retardant copper-clad plate produced can meet the market use demand, is safe, and reduces environmental pollution.

Description

Technical Field

[0001] This invention relates to the field of flame retardant composites and copper clad laminates, specifically to a method for manufacturing a halogen-free paper-based adhesive and a halogen-free composite paper-based copper clad laminate. Background Technology

[0002] Halogen-based flame retardants are a common environmental pollutant. During combustion, halogen-containing flame retardants release substances that are harmful to human health and the environment (such as dioxins). Therefore, halogen-free composite paper-based copper clad laminates are a pressing issue for copper clad laminate developers, making the research of such a material extremely urgent.

[0003] Existing literature discloses a manufacturing method for a high-temperature resistant paper-based composite copper-clad laminate (CN115648750B). This method primarily uses halogen-containing substances such as brominated epoxy resin and tetrabromobisphenol A, along with triphenyl phosphate, as the main flame-retardant material to achieve the required flame-retardant rating. However, this product uses halogen-containing substances and triphenyl phosphate as flame retardants. Triphenyl phosphate is a CHCC-restricted substance, classified as halogenated 22F, which poses environmental pollution and health risks.

[0004] Existing literature also discloses a high-toughness halogen-free CEM-3 copper clad laminate (CN107771418B), whose raw materials include the following components in parts by weight: 75-120 parts of phenolic epoxy resin, 300-450 parts of flame-retardant modified liquid halogen-free epoxy resin, 150-250 parts of flame-retardant modified solid halogen-free epoxy resin, 25-50 parts of curing agent, 0.10-0.30 parts of curing accelerator, and 100-200 parts of organic solvent. This high-toughness halogen-free CEM-3 copper clad laminate not only has good heat resistance and chemical resistance, but also reduces environmental pollution.

[0005] Currently, most halogen-free boards are primarily phosphorus-nitrogen based, offering good heat dissipation and insulation. However, it has been found that these halogen-free boards are prone to circuit board performance defects during manufacturing, requiring higher manufacturing standards and increasing the difficulty of the process. Furthermore, the CEM-3 copper-clad laminate uses felt and double-sided cloth as composite reinforcement materials; while the 22F copper-clad laminate, which uses paper and double-sided cloth as composite reinforcement materials, is not yet available in the market as a halogen-free board. In view of this, the applicant has conducted in-depth research to address the aforementioned deficiencies in the prior art, leading to this application. Summary of the Invention

[0006] One objective of this invention is to provide a method for manufacturing a halogen-free paper-based adhesive. The resulting adhesive, used as a paper-based impregnation solution, is not only halogen-free, environmentally friendly, and pollution-free, but also has excellent flame-retardant properties. Furthermore, it overcomes the adverse effects of adhesives on circuit board performance and manufacturing processes.

[0007] To achieve the above objectives, the solution of the present invention is:

[0008] A method for manufacturing a halogen-free paper-based adhesive includes the following steps:

[0009] S201: Preparation of epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin; the manufacturing method includes the following steps S101-S105.

[0010] S101: Add 3300-4900 parts by weight of 128 epoxy resin and 750-1150 parts by weight of phosphorus-containing halogen-free flame retardant to the standby reactor, and stir continuously. Heat to 150℃ and keep at a constant temperature for 120 minutes. Cool to 50℃ and set aside the produced A glue. Continue stirring.

[0011] S102: Add 800-1200 parts by weight of phenol, 900-1350 parts by weight of paraformaldehyde, 600-900 parts by weight of methanol, and 600-900 parts by weight of melamine to the reactor, and continue stirring for 10 minutes.

[0012] S103: Next, add 6-13 parts by weight of ethylenediamine catalyst to the reactor of S102 and continue stirring for 10 minutes;

[0013] S104: Raise the temperature to 90±2℃ and start timing, control the temperature at 90-94℃ and maintain it for 60 minutes, then cool it to 50℃;

[0014] S105: Add 1150-1750 parts by weight of methanol as a neutralizing agent and 4050-6050 parts by weight of A glue produced by S101 to the product obtained in S104. Heat to 90±2℃ and start timing. Control the temperature at 90-94℃ and maintain for 60 minutes. Cool to 50℃ to obtain epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin.

[0015] S202: Add 1600-2400 parts by weight of epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin, 800-1200 parts by weight of polyhydroxycyanamide resin, 1600-2400 parts by weight of thermosetting phenolic resin, and 1600-2400 parts by weight of tung oil modified phenolic resin to the reactor, and continue stirring for 60 minutes.

[0016] S203: Next, add 1200-1800 parts by weight of 128 epoxy resin to the reactor of S202 and continue stirring for 30 minutes;

[0017] S204: Next, add 150-250 parts by weight of titanium dioxide, 400-600 parts by weight of silica powder, and 150-250 parts by weight of aluminum hydroxide to the reactor of S203, and continue stirring for 30 minutes.

[0018] S205: Next, add 4-10 parts by weight of coupling agent KH-560 to the reaction vessel of S204, and continue stirring for 30 minutes before taking samples to determine GT.

[0019] S206: Next, take a sample from the reaction vessel in S205 to measure the GT value. Based on the measured GT value, add 3-8 parts by weight of imidazole and continue stirring.

[0020] S207: Next, 1300-1950 parts by weight of methanol are added to the reactor of S206 to obtain halogen-free paper-based adhesive.

[0021] The preparation method of the tung oil-modified phenolic resin in S202 is as follows:

[0022] (1) Add 200-300 parts by weight of methanol, 100-150 parts by weight of paraformaldehyde, and 150-200 parts by weight of melamine to the standby reactor, and continue stirring for 10 minutes.

[0023] (2) Next, add 0.1-0.5 parts by weight of formic acid to the reactor in step (1) and continue stirring for 10 minutes;

[0024] (3) Raise the temperature to 68±2℃ and start timing. Control the temperature at 72±2℃ and maintain it for 300 minutes. Start sampling to determine the turbidity of methanol.

[0025] (4) After the reaction in step (3), the methanol turbidity is measured every 30 minutes. Once the turbidity reaches the standard, the reaction is stopped. The reaction endpoint is reached after about 360 minutes of heat preservation. The product is then cooled to 50°C and stirred.

[0026] (5) Add 2750-4150 parts by weight of phenol, 500-750 parts by weight of cashew phenol and 1200-1800 parts by weight of tung oil to the reactor and continue stirring for 10 minutes.

[0027] (6) Add 10-20 parts by weight of methanol and 10-20 parts by weight of p-toluenesulfonic acid to the standby reaction vessel and stir until completely dissolved;

[0028] (7) Following the reaction in step (5), add 20-40 parts by weight of the product obtained in the prepared reaction vessel in step (6) to step (5) and continue stirring for 10 minutes.

[0029] (8) Raise the temperature to 90±2℃ and start timing. Keep the temperature at 90±2℃ for 120 minutes and continue stirring.

[0030] (9) Add 10-15 parts by weight of water and 10-15 parts by weight of triethanolamine to the standby reactor, and continue stirring for 10 minutes;

[0031] (10) Following the reaction in step (8), add 20-30 parts by weight of the product obtained in the prepared reaction vessel in step (9) to step (8), continue stirring for 10 minutes, and begin cooling to 60°C.

[0032] (11) Next, add 2450-3700 parts by weight of formaldehyde to the reactor in step (10) and continue stirring for 10 minutes;

[0033] (12) Next, add 30-50 parts by weight of ammonia water and 50-100 parts by weight of triethylamine to the reactor in step (11), and continue stirring for 10 minutes.

[0034] (13) Raise the temperature to 95±2℃ and start timing. Control the temperature at 95±2℃ and maintain it for 20 minutes. Continue stirring. Start sampling to determine GT. After reaching the standard, start vacuum dehydration and start timing. Slowly increase the vacuum degree. When the temperature drops to 70±2℃, heat it. Grind it until GT reaches the standard. Start cooling to 50℃ and continue stirring.

[0035] (14) Next, in step (13), 500-700 parts by weight of B glue and 3250-4850 parts by weight of methanol obtained in step (4) are added to the reactor to obtain tung oil modified phenolic resin.

[0036] In step S202, the preparation method of the polyhydroxycyanamide resin is as follows:

[0037] (1) Add 200-300 parts by weight of methanol, 100-150 parts by weight of paraformaldehyde, and 150-200 parts by weight of melamine in sequence, and stir for 10 minutes.

[0038] (2) Next, add 0.2-0.4 parts by weight of formic acid, stir for 10 minutes, and take a sample to measure the pH value to confirm that pH = 6 ± 0.2;

[0039] (3) Raise the temperature to 68±2℃ and start timing. Control the temperature at 72±2℃ and maintain it for 300 minutes. Start sampling to determine the turbidity of methanol.

[0040] (4) Then, the methanol turbidity was measured every 30 minutes. Once the turbidity reached the standard, the reaction was stopped. The reaction endpoint was reached after about 360 minutes of heat preservation, and then cooled to 50°C.

[0041] (5) Then add 400-600 parts by weight of melamine cyanurate SX-MC-15 and continue stirring to obtain polyhydroxycyanamide resin.

[0042] In step S202, the preparation method of the thermosetting phenolic resin is as follows:

[0043] (1) Add 2600-3850 parts by weight of phenol, 2100-3150 parts by weight of formaldehyde and 10-20 parts by weight of oxalic acid in sequence, and stir for 10 minutes.

[0044] (2) Heat to 70-75℃ and then turn off the heating; when the temperature reaches 85-90℃, start turning on the water to control the temperature;

[0045] (3) Heat to 90℃ and start recording the reaction time. Keep the temperature at 95±2℃ for the reaction.

[0046] (4) Start observing the resin reaction after 25 minutes of heat preservation reaction. The normal emulsification point time is 35 minutes.

[0047] (5) After the resin reaction emulsifies for 80-90 minutes, and the total reaction time is 120 minutes, dehydration begins. After the temperature drops to 70℃, heating begins. When the temperature rises back to 70℃, vacuum sampling is stopped.

[0048] (6) Then add 1800-2650 parts by weight of methanol as solvent and stir for 1 hour. When the temperature cools down to below 50°C, take a sample and send it for testing; to obtain thermosetting phenolic resin.

[0049] Another objective of this invention is to provide a method for manufacturing halogen-free composite paper-based copper clad laminates, which is a new production process for halogen-free 22F copper clad laminates. It is not only halogen-free, environmentally friendly, and pollution-free, and has excellent flame-retardant properties, but also overcomes the adverse problems to its performance and manufacturing process in circuit board applications.

[0050] A method for manufacturing a halogen-free composite paper-based copper-clad laminate includes the following steps:

[0051] S301: Prepare a halogen-free paper-based adhesive according to the above-mentioned method for manufacturing a halogen-free paper-based adhesive;

[0052] S302: Preparation of halogen-free paper-based prepreg: The obtained halogen-free paper-based adhesive is used for gluing wood pulp paper to obtain a paper-based prepreg.

[0053] S303: Preparation of fabric-based adhesive;

[0054] S304: The prepared cloth-based adhesive is used for applying adhesive to electronic-grade fiberglass cloth to obtain a cloth-based prepreg.

[0055] S305: Preparation of halogen-free copper clad laminate: Sequentially stack one cloth-based prepreg, six paper-based prepregs, one cloth-based prepreg, and one uncoated copper foil, and press them by controlling the temperature and pressure of a hot press to obtain a halogen-free composite paper-based copper clad laminate.

[0056] The specific step of S302 is as follows: halogen-free paper-based adhesive is applied by impregnation at a concentration of 130-155 g / m². 2 The bleached wood pulp paper is dried in an oven at a temperature of 115-220℃. The preimpregnated material is heated in the oven for 2-5 minutes, resulting in a semi-cured sheet with a thickness of 150-250μm and a volatile content of 3-5%. The semi-cured sheet is pressed at 0.7±0.2MPa for 6 minutes, with a flowability of 4.5-6.5%. It is then dried into a semi-cured sheet and cut into the required size to produce a paper-based semi-cured sheet.

[0057] The specific steps of S304 are as follows: the obtained halogen-free cloth-based adhesive is impregnated with 105-210 g / m 2 The electronic-grade fiberglass cloth is dried in an oven at a temperature of 100-220℃. The pre-impregnated body is heated in the oven for 4-10 minutes. The thickness of the resulting semi-cured sheet is 140-230μm. The volatile content of the semi-cured sheet is ≤0.5%. The semi-cured sheet is dried and cut into the required size to make a cloth-based semi-cured sheet.

[0058] In S305, the hot press is pressed for 100-190 minutes. The pressing conditions are as follows: the pressure is gradually increased from 0 MPa to 2 MPa in the first 5 minutes, and then gradually increased from 2 MPa to 8.5 MPa. The hot pressing temperature is 120-190℃, resulting in a 1.6mm thick paper-based composite copper-clad laminate.

[0059] The specific steps for preparing the fabric-based adhesive using S303 are as follows:

[0060] (1) Add 40-60 parts by weight of benzoxazine resin, 40-60 parts by weight of reactive phosphazene compound, 40-60 parts by weight of polyacrylic acid, 40-60 parts by weight of epoxy resin halogen-free flame retardant, and 310-460 parts by weight of phosphorus-containing epoxy resin in sequence, and continue stirring for 30 minutes.

[0061] (2) Next, add 40-60 parts by weight of solid phenolic resin and 160-240 parts by weight of acetone, and continue stirring for 30 minutes.

[0062] (3) Next, add 60-90 parts by weight of silica powder and 30-40 parts by weight of aluminum hydroxide, and continue stirring for 30 minutes;

[0063] (4) Next, add 60-90 parts by weight of melamine cyanurate SX-MC-15 and 0.5-2 parts by weight of coupling agent KH-560, and continue stirring for 20 minutes;

[0064] (5) Next, add 0.5-1.5 parts by weight of Brilliant Yellow and continue stirring for 30 minutes. Then, start taking samples to determine GT.

[0065] (6) Next, according to the GT value determined by S305, add 0.2-0.6 parts by weight of imidazole and continue stirring to obtain halogen-free cloth-based adhesive.

[0066] The advantages of this invention over existing technologies, achieved by adopting the above scheme, are as follows: It proposes a method for manufacturing halogen-free paper-based adhesives and halogen-free composite paper-based copper-clad laminates, using epoxy resin-modified nitrogen-phosphorus phenolic flame-retardant resin as the main flame-retardant material, thereby improving the vertical flammability rating of the board. This invention employs a reactive method to simultaneously introduce N and P into the molecular framework of the epoxy resin, which on the one hand improves the vertical flammability rating of the board, and on the other hand avoids the impact of reduced PCB performance and increased manufacturing process standards and difficulties during PCB board production. The resulting halogen-free flame-retardant copper-clad laminate meets market demands, ensuring safety and reducing environmental pollution. The produced copper-clad laminate achieves an FV-0 vertical flammability rating, with bromine <1000ppm, chlorine <1000ppm, and total bromine and chlorine <1500ppm. Detailed Implementation

[0067] The following detailed explanation of this case, in conjunction with specific implementation methods, provides further details.

[0068] This case relates to a method for manufacturing a modified nitrogen-phosphorus phenolic resin, comprising the following steps:

[0069] S101: Add 4065 parts by weight of 128 epoxy resin and 935 parts by weight of phosphorus-containing halogen-free flame retardant to the standby reactor, and stir continuously. Heat to 150°C and keep at a constant temperature for 120 minutes. Cool to 50°C and set aside the produced A glue. Continue stirring.

[0070] S102: Add 975 parts by weight of phenol, 1100 parts by weight of paraformaldehyde, 750 parts by weight of methanol and 750 parts by weight of melamine to the reactor, and continue stirring for 10 minutes.

[0071] S103: Next, add 10 parts by weight of ethylenediamine catalyst to the reactor of S102 and continue stirring for 10 minutes;

[0072] S104: Raise the temperature to 90±2℃ and start timing, control the temperature at 90-94℃ and maintain it for 60 minutes, then cool it to 50℃;

[0073] S105: Add 1425 parts by weight of methanol as a neutralizing agent and 5000 parts by weight of A glue produced by S101 to the product obtained in S104. Heat to 90±2℃ and start timing. Control the temperature at 90-94℃ and maintain for 60 minutes. Cool to 50℃ to obtain epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin.

[0074] In S101, 128 epoxy resin is a phenolic alicyclic epoxy resin, and its index parameters are given as follows: epoxy equivalent (g / mol): 184.0-194.0, hydrolyzable fluorine: ≤0.1000%, viscosity (25℃), (mPa·S): 11000-14000, volatile matter: ≤0.200%, color: ≤60.

[0075] In S101, the phosphorus-containing halogen-free flame retardant, specifically example, uses XS-EP-10 phosphorus-containing halogen-free flame retardant, a product manufactured by Zhejiang Xusen Flame Retardant Co., Ltd., which is an additive-type halogen-free flame retardant containing phosphorus and nitrogen monomers. A preferred example of its parameters is: phosphorus content (%): ≥13%, nitrogen content (%): ≥5.8%, water content (%): ≤0.5%, relative density (g / cm³). 3 ): 1.6-1.9 g / cm³ 3 .

[0076] In S102, regarding paraformaldehyde, a preferred example of its parameters is given as follows: aldehyde content (calculated as formaldehyde): ≥92%; ash content: ≤0.1%; water-insoluble matter: ≤0.1%; acidity (calculated as formic acid): ≤0.05%; pH value: 4.0-6.0. Regarding melamine, a preferred example of its parameters is given as follows: pH value: 8.0±1.5; moisture (%): ≤0.1%; melamine (ω / %): ≥99.5%; methanol water solubility (%): ≤20min; ash content (%): ≤0.03%.

[0077] In S103, regarding ethylenediamine, a preferred example of its parameters is given as follows: Ethylenediamine (ω / %): ≥99.5%. Moisture (ω / %): ≤0.5%.

[0078] This application describes an epoxy resin-modified nitrogen-phosphorus phenolic flame-retardant resin, which can be used as a primary flame-retardant material. Its superior performance is particularly evident in paper-based substrates and corresponding copper-clad laminates. The performance benefits are twofold: firstly, its excellent flame-retardant effect. The linear phenolic resin acts as a curing agent for the epoxy resin, cross-linking it to form a network-like three-dimensional structure. The synergistic effect of the PN flame-retardant components further enhances the flame-retardant effect, thereby improving the vertical burning rating of the board (achieving FV-0). Secondly, its N and P flame-retardant system is reactive, meaning that N and P are simultaneously introduced into the molecular framework of the epoxy resin through an innovative manufacturing method. Through long-term research and exploration, the applicant has discovered that the current application of phosphorus-nitrogen halogen-free flame retardants in copper-clad laminates leads to reduced PCB performance and increased manufacturing difficulty and standards. This is because the N and P flame-retardant system of current phosphorus-nitrogen halogen-free flame retardants is additive. During application, N and P can leak from the substrate resin and mix into the etching solution, causing this problem. The applicant discovered the key technical problem and proposed a solution. By transforming the additive type into a reactive type through the manufacturing method, that is, by simultaneously introducing N and P into the molecular skeleton of epoxy resin, the resulting epoxy resin modified with nitrogen, phosphorus, phenol and formaldehyde flame retardant resin can exert its flame retardant and halogen-free safety effects, while also avoiding the impact of reduced PCB performance and increased manufacturing process standards and difficulty during PCB circuit board manufacturing.

[0079] This application discloses a method for manufacturing epoxy-modified nitrogen-phosphorus phenolic flame-retardant resin, wherein 128 epoxy resin and a phosphorus-containing halogen-free flame retardant undergo a relevant heating polymerization reaction to obtain a nitrogen-phosphorus resin compound; melamine and formaldehyde react under relevant heating catalytic conditions to obtain a polyhydroxymethyl compound; phenol and formaldehyde react under relevant heating catalytic conditions to obtain a phenolic resin compound; and the polyhydroxymethyl compound reacts with the phenolic resin compound to obtain a nitrogen-containing phenolic compound.

[0080] The innovative design concept of this application's manufacturing method is to first introduce PN into the molecular chain through a reaction, and then stabilize the chain through related reactions, so as to simultaneously and effectively introduce N and P into the molecular backbone of epoxy resin. Specifically, it is reflected in the following steps: First, prepare material A, 128 epoxy resin and XS-EP-10 halogen-free flame retardant are polymerized at 150℃ for 2 hours, introducing PN into the molecular chain. However, the substituted molecular chain is unstable at this time and is easily replaced by the original molecular chain over time. Then, after the S102-S104 reaction, linear phenolic resin is obtained. Then, material A and methanol are added, and the temperature is raised to 90℃ for reflux polymerization. The linear phenolic resin is cross-linked and cured to form a three-dimensional network structure. The molecular weight of material A increases, making the PN-substituted molecular chain more stable.

[0081] This application also relates to a method for manufacturing a halogen-free paper-based adhesive, comprising the following steps:

[0082] S201: Preparation of epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin; prepared according to the above-described method for manufacturing a modified nitrogen-phosphorus phenolic resin;

[0083] S202: Add 2000 parts by weight of epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin, 1000 parts by weight of polyhydroxycyanamide resin, 2000 parts by weight of thermosetting phenolic resin, and 2000 parts by weight of tung oil modified phenolic resin to the reactor, and continue stirring for 60 minutes.

[0084] S203: Next, add 1500 parts by weight of 128 epoxy resin to the reactor of S202 and continue stirring for 30 minutes.

[0085] S204: Next, add 200 parts by weight of titanium dioxide, 500 parts by weight of silica powder, and 200 parts by weight of aluminum hydroxide to the reactor of S203, and continue stirring for 30 minutes.

[0086] S205: Next, add 6 parts by weight of coupling agent KH-560 to the reaction vessel of S204, and continue stirring for 30 minutes before taking samples to determine GT.

[0087] S206: Next, take a sample from the reaction vessel in S205 to measure the GT value. Based on the measured GT value, add 6 parts by weight of imidazole and continue stirring.

[0088] S207: Next, 1600 parts by weight of methanol are added to the reactor of S206 to obtain halogen-free paper-based adhesive.

[0089] In the manufacturing method, the epoxy resin curing agent can be dicyandiamide, linear phenolic resin, or diaminophenyl sulfone. The epoxy resin curing accelerator can be 2-methylimidazole, 2-ethyl, 4-methylimidazole, 2-phenylimidazole, 2-phenyl, 4-methylimidazole, etc. In this scheme, the epoxy curing agent is tung oil-modified phenolic resin and thermosetting phenolic resin, and the accelerator is 2-methylimidazole. The final halogen-free paper-based adhesive has the following preferred specifications: solid content: 61±2%, gelation time: 125s±20s / 171℃.

[0090] In S203, regarding the 128 epoxy resin, a preferred example of its parameters is given as follows: epoxy equivalent (g / mol): 184.0-194.0; hydrolyzable fluorine: ≤0.1000%; viscosity (25℃), (mPa·S): 11000-14000; volatile matter: ≤0.200%; color: ≤60.

[0091] In S204, regarding titanium dioxide, a preferred example of its parameter indicators is given as follows: titanium dioxide (TiO2) content %: ≥98%, volatile matter at 105℃: ≤0.5%, water-soluble matter: ≤0.5%, sieve residue (45μm or +325 mesh): ≤0.1, color L*: ≥93, bleaching power: ≥100, pH value of aqueous suspension: 6.0-8.5.

[0092] In S205, the coupling agent KH-560 is an epoxy silane coupling agent, specifically 3-(2,3-epoxypropoxy)propyltrimethoxysilane. A preferred example of its parameters is as follows: density (ρ20): 1.060-1.080; refractive index: 1.4220-1.4320; free chlorine (mg / kg): ≤100ppm; purity (GC) (%): ≥95%.

[0093] This application discloses a method for manufacturing halogen-free paper-based adhesive, in which the resulting halogen-free paper-based adhesive is used as a paper-based impregnation solution. In practice, when phosphorus-nitrogen-based halogen-free flame retardants are used in paper-based impregnation solutions, the problem of nitrogen and phosphorus leaching from the substrate resin and mixing into the etching solution is more likely to occur. Therefore, this application, based on the manufactured epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin, uses manufacturing methods S201-S207 to produce a halogen-free paper-based adhesive for use in paper-based copper-clad laminates. Because it uses a reactive method to introduce nitrogen and phosphorus into the molecular framework of the epoxy resin, it produces halogen-free paper-based flame-retardant copper-clad laminates that meet market demands without affecting the performance and manufacturing process of the PCB circuit board, thus ensuring safety and reducing environmental pollution.

[0094] Furthermore, in step S202, a preferred preparation method for tung oil-modified phenolic resin is proposed, with the specific steps as follows:

[0095] (1) Add 245 parts by weight of methanol, 125 parts by weight of paraformaldehyde and 150 parts by weight of melamine to the standby reactor and continue stirring for 10 minutes.

[0096] (2) Next, add 0.3 parts by weight of formic acid to the reaction vessel in step (1) and continue stirring for 10 minutes; take a sample to measure the pH value to confirm that pH = 6 ± 0.2;

[0097] (3) Raise the temperature to 68±2℃ and start timing. Control the temperature at 72±2℃ and maintain it for 300 minutes. Start sampling to determine the turbidity of methanol.

[0098] (4) After the reaction in step (3), the methanol turbidity is measured every 30 minutes. Once the turbidity reaches the standard, the reaction is stopped. The reaction endpoint is reached after about 360 minutes of heat preservation. The product is then cooled to 50°C and stirred.

[0099] (5) Add 3422 parts by weight of phenol, 611 parts by weight of cashew phenol and 1467 parts by weight of tung oil to the reactor and continue stirring for 10 minutes.

[0100] (6) Add 17 parts by weight of methanol and 17 parts by weight of p-toluenesulfonic acid to the standby reaction vessel and stir until completely dissolved;

[0101] (7) Following the reaction in step (5), add 30 parts by weight of the product obtained in the prepared reaction vessel in step (6) to step (5) and continue stirring for 10 minutes.

[0102] (8) Raise the temperature to 90±2℃ and start timing. Keep the temperature at 90±2℃ for 120 minutes and continue stirring.

[0103] (9) Add 12 parts by weight of water and 12 parts by weight of triethanolamine to the standby reactor and continue stirring for 10 minutes;

[0104] (10) Following the reaction in step (8), add 25 parts by weight of the product obtained in the prepared reaction vessel in step (9) to step (8), continue stirring for 10 minutes, and begin cooling to 60°C.

[0105] (11) Next, add 3056 parts by weight of formaldehyde to the reactor in step 10) and continue stirring for 10 minutes;

[0106] (12) Next, add 40 parts by weight of ammonia water and 79 parts by weight of triethylamine to the reactor in step (11), and continue stirring for 10 minutes.

[0107] (13) Raise the temperature to 95±2℃ and start timing. Control the temperature at 95±2℃ and maintain it for 20 minutes. Continue stirring. Start sampling to determine GT. After reaching the standard, start vacuum dehydration and start timing. Slowly increase the vacuum degree. When the temperature drops to 70±2℃, heat it. Grind it until GT reaches the standard. Start cooling to 50℃ and continue stirring.

[0108] (14) Next, in step (13), 600 parts by weight of B glue and 4033 parts by weight of methanol obtained in step (4) are added to the reactor to obtain tung oil modified phenolic resin.

[0109] In step (1), for paraformaldehyde, a preferred example of its parameters is given as follows: aldehyde content (as formaldehyde): ≥92%; ash content: ≤0.1%; water-insoluble matter: ≤0.1%; acidity (as formic acid): ≤0.05%; pH value: 4.0-6.0. For melamine, a preferred example of its parameters is given as follows: pH value: 8.0±1.5; moisture (%): ≤0.1%; melamine (ω / %): ≥99.5%; methanol water solubility (%): ≤20min; ash content (%): ≤0.03%.

[0110] In step (2), for formic acid, a preferred example of its parameters is given as follows: formic acid (ω / %): ≥94%, dilution test (sample + water = 1 + 3): not turbid, chloride (as Cl), (ω / %): ≤0.0005%, evaporation residue (ω / %): ≤0.006%.

[0111] In step (5), regarding tung oil, a preferred example of its parameters is given as follows: specific gravity: 0.9360-0.9395; refractive index: 1.5185-1.5225; iodine value: 163-173; saponification value: 190-195; thermal polymerization test (wax test) (coking time): solidifies within 7 min 30 s at 282℃, does not stick to the knife when cut, and crumbles easily when pressed; appearance: transparent after standing for 24 hours, without other impurities; β-tung oil test: no crystal precipitation; odor: has the inherent normal odor of tung oil, no off-odor; moisture and volatile matter (%) (105℃): ≤0.1; acid value: ≤3.0.

[0112] In step (6), a preferred example of the parameters of toluenesulfonic acid is given as follows: p-toluenesulfonic acid (ω / %): ≥88%, m-methylbenzenesulfonic acid (ω / %): ≤1.0%, o-methylbenzenesulfonic acid (ω / %): ≤1.0%, sulfuric acid content (ω / %): ≤1.0%, and residue on ignition (ω / %): ≤0.1%.

[0113] In step (12), a preferred example of the parameters for ammonia water is given as follows: content (NH3) (ω / %): 25-28%, evaporation residue (ω / %): ≤0.002%. A preferred example of the parameters for triethylamine is given as follows: triethylamine (ω / %): ≥99.5%, monoethylamine (ω / %): ≤0.1%, diethylamine (ω / %): ≤0.1%.

[0114] Furthermore, in step S202, a preferred preparation method for the polyhydroxycyanamide resin is proposed, with the specific steps as follows:

[0115] (1) Add 240 parts by weight of methanol, 123 parts by weight of paraformaldehyde and 150 parts by weight of melamine in sequence, and stir for 10 minutes.

[0116] Preferably, the paraformaldehyde parameters are provided as follows: pH value 4-6, aldehyde content (calculated as formaldehyde) selected as either 96% or 92%, and 92% is selected in this scheme;

[0117] (2) Next, add 0.29 parts by weight of formic acid, stir for 10 minutes, and take a sample to determine the pH value to confirm that pH = 6 ± 0.2; preferably, the organic acid catalyst formic acid is selected from 94%, 90%, and 85% formic acid (ω / %), and 94% is selected in this scheme; (3) raise the temperature to 68 ± 2℃ and start timing, control the temperature at 72 ± 2℃ and maintain it for 300 minutes, and start taking a sample to determine the turbidity of methanol;

[0118] (4) Then, the methanol turbidity was measured every 30 minutes. Once the turbidity reached the standard, the reaction was stopped. The reaction endpoint was reached after about 360 minutes of heat preservation, and then cooled to 50°C.

[0119] (5) Next, add 500 parts by weight of melamine cyanurate SX-MC-15 and continue stirring to obtain polyhydroxycyanamide resin.

[0120] A modified melamine resin is obtained by reacting a specific ratio of paraformaldehyde, melamine, and methanol with formic acid catalysis via reflux. This resin contains -OH (hydroxyl) and -R (-R being amino or OOH carboxyl groups). Then, SX-MC-15 melamine cyanurate (a supramolecular aggregate) is added and mixed thoroughly. The resulting resin is called polyhydroxycyanuramine resin. The melamine cyanurate SX-MC-15 is a supramolecular aggregate material formed by the self-composite formation of melamine and cyanuric acid through hydrogen bonding, with a bulk density of 0.47 g / cm³. 3 The final obtained polycyanamide resin has a nitrogen (N) atomic content ≥ 25%.

[0121] Furthermore, in step S202, a preferred preparation method for the thermosetting phenolic resin is proposed, with the specific steps as follows:

[0122] (1) Add 3200 parts by weight of phenol, 2600 parts by weight of formaldehyde and 17 parts by weight of oxalic acid in sequence, and stir for 10 minutes;

[0123] Preferably, the organic catalyst oxalic acid, in the form of H2C2O4·2H2O, has a mass fraction (%) of 99.6%, 99.0%, or 96.0%, and the sulfate ion, in the form of SO4, has a mass fraction (%) of 0.07%, 0.10%, 0.20%, or 0.40%. In this specific embodiment, the mass fraction of H2C2O4·2H2O is 99.6%, and the mass fraction of the sulfate ion, in the form of SO4, is 0.07%.

[0124] (2) Heat to 70-75℃ and then turn off the heating; when the temperature reaches 85-90℃, start turning on the water to control the temperature;

[0125] (3) Heat to 90℃ and start recording the reaction time. Keep the temperature at 95±2℃ for the reaction.

[0126] (4) Start observing the resin reaction after 25 minutes of heat preservation reaction. The normal emulsification point time is 35 minutes.

[0127] (5) After the resin reaction emulsifies for 80-90 minutes, and the total reaction time is 120 minutes, dehydration begins. After the temperature drops to 70℃, heating begins. When the temperature rises back to 70℃, vacuum sampling is stopped.

[0128] (6) Next, add 2200 parts by weight of methanol as a solvent and stir for 1 hour. When the temperature cools down to below 50°C, take a sample for testing to obtain thermosetting phenolic resin. Preferably, the obtained thermosetting phenolic resin has a solid content of 50±2% and the glue is transparent and clear.

[0129] This application also relates to a method for manufacturing a halogen-free composite paper-based copper-clad laminate, comprising the following steps:

[0130] S301: Preparation of halogen-free paper-based adhesive; prepared according to the above-described method for manufacturing halogen-free paper-based adhesive;

[0131] S302: Preparation of halogen-free paper-based prepreg: The obtained halogen-free paper-based adhesive is used for gluing wood pulp paper to obtain a paper-based prepreg.

[0132] S303: Preparation of fabric-based adhesive;

[0133] S304: The prepared cloth-based adhesive is used for applying adhesive to electronic-grade fiberglass cloth to obtain a cloth-based prepreg.

[0134] S305: Preparation of halogen-free copper clad laminate: Sequentially stack one cloth-based prepreg, six paper-based prepregs, one cloth-based prepreg, and one uncoated copper foil, and press them by controlling the temperature and pressure of a hot press to obtain a halogen-free composite paper-based copper clad laminate.

[0135] This application discloses a method for manufacturing halogen-free composite paper-based copper clad laminates, which is a novel production process for halogen-free 22F copper clad laminates. The method utilizes a special halogen-free paper-based adhesive impregnated with the paper base, resulting in a halogen-free composite paper-based copper clad laminate. Because the internal process involves reactive introduction of nitrogen and phosphorus into the molecular framework of the epoxy resin, this process achieves a halogen-free composite paper-based flame-retardant copper foil laminate that meets market demands without affecting the performance and manufacturing process of the PCB circuit board. The resulting copper clad laminate achieves an FV-0 vertical burning rating, with bromine <1000ppm, chlorine <1000ppm, and a total bromine and chlorine content <1500ppm.

[0136] The S302 step prepares a halogen-free paper-based prepreg. A preferred preparation method involves impregnating the prepreg with a halogen-free paper-based adhesive at a concentration of 135 g / m³. 2 The bleached wood pulp paper is dried in an oven at a temperature of 115-220℃. The preimpregnated material is heated in the oven for 2-5 minutes, resulting in a semi-cured sheet with a thickness of 150-250μm and a volatile content of 3-5%. The semi-cured sheet is pressed at 0.7±0.2MPa for 6 minutes, with a flowability of 4.5-6.5%. It is then dried into a semi-cured sheet and cut into the required size to produce a paper-based semi-cured sheet.

[0137] The S304-based fabric semi-cured sheet is prepared by a preferred method in which the obtained halogen-free fabric-based adhesive is impregnated with 210 g / m³ of adhesive. 2 The electronic-grade fiberglass cloth is dried in an oven at a temperature of 100-220℃. The pre-impregnated body is heated in the oven for 4-10 minutes, resulting in a semi-cured sheet with a thickness of 140-230μm. The semi-cured sheet has a volatile content of ≤0.5%, a solubility of 50-55%, and an adhesive content of 39-43%. The semi-cured sheet is dried and cut into the required size to produce a cloth-based semi-cured sheet.

[0138] In S305, a preferred embodiment of the specific operation of the pressing process is as follows: the hot press is pressed for 100-190 minutes, and the pressing conditions are: the pressure is gradually increased from 0MPa to 2MPa in the first 5 minutes, and then gradually increased from 2MPa to 8.5MPa. The hot pressing temperature is 120-190℃, resulting in a 1.6mm thick paper-based composite copper-clad laminate.

[0139] The S303 is used to prepare the fabric-based adhesive, and a preferred preparation method is provided, with the specific steps as follows:

[0140] (1) Add 50 parts by weight of benzoxazine resin, 50 parts by weight of reactive phosphazene compound, 50 parts by weight of polyacrylic acid, 50 parts by weight of epoxy resin halogen-free flame retardant, and 376 parts by weight of phosphorus-containing epoxy resin in sequence, and continue stirring for 30 minutes.

[0141] (2) Next, add 50 parts by weight of solid phenolic resin and 194 parts by weight of acetone, and continue stirring for 30 minutes.

[0142] (3) Next, add 75 parts by weight of silica powder and 30 parts by weight of aluminum hydroxide, and continue stirring for 30 minutes;

[0143] (4) Next, add 75 parts by weight of melamine cyanurate SX-MC-15 and 1 part by weight of coupling agent KH-560, and continue stirring for 20 minutes.

[0144] (5) Next, add 1 part by weight of Brilliant Yellow and continue stirring for 30 minutes. Then, start taking samples to determine GT.

[0145] (6) Next, according to the GT value determined by S305, 0.4 parts by weight of imidazole are added and stirring is continued to obtain halogen-free fabric-based adhesive. Preferably, the halogen-free fabric-based adhesive has the following specifications: solid content: 70±2%; gelation time: 220s±20s / 171℃.

[0146] The following examples and comparative cases illustrate the use of composite paper-based copper clad laminate products.

[0147] Example 1

[0148] S100: Preparation of epoxy resin modified nitrogen-phosphorus-phenolic flame-retardant resin

[0149] S101: Add 4065 parts by weight of 128 epoxy resin and 750 parts by weight of phosphorus-containing halogen-free flame retardant to the standby reactor, and stir continuously. Heat to 150°C and keep at a constant temperature for 120 minutes. Cool to 50°C and set aside the A glue produced. Continue stirring.

[0150] S102: Add 975 parts by weight of phenol, 1100 parts by weight of paraformaldehyde, 750 parts by weight of methanol and 750 parts by weight of melamine to the reactor, and continue stirring for 10 minutes.

[0151] S103: Next, add 10 parts by weight of ethylenediamine catalyst to the reactor of S102 and continue stirring for 10 minutes;

[0152] S104: Raise the temperature to 90±2℃ and start timing, control the temperature at 90-94℃ and maintain it for 60 minutes, then cool it to 50℃;

[0153] S105: Add 1425 parts by weight of methanol as a neutralizing agent and 5000 parts by weight of A glue produced by S101 to the product obtained in S104. Heat to 90±2℃ and start timing. Control the temperature at 90-94℃ and maintain for 60 minutes. Cool to 50℃ to obtain epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin.

[0154] S200: Preparation of halogen-free paper-based adhesive

[0155] S201: Preparation of tung oil-modified phenolic resin:

[0156] (1) Add 245 parts by weight of methanol, 125 parts by weight of paraformaldehyde and 150 parts by weight of melamine to the standby reactor and continue stirring for 10 minutes.

[0157] (2) Next, add 0.3 parts by weight of formic acid to the reactor in step (1) and continue stirring for 10 minutes;

[0158] (3) Raise the temperature to 68±2℃ and start timing. Control the temperature at 72±2℃ and maintain it for 300 minutes. Start sampling to determine the turbidity of methanol.

[0159] (4) After the reaction in step (3), the methanol turbidity is measured every 30 minutes. Once the turbidity reaches the standard, the reaction is stopped. The reaction endpoint is reached after about 360 minutes of heat preservation. The product is then cooled to 50°C and stirred.

[0160] (5) Add 3422 parts by weight of phenol, 611 parts by weight of cashew phenol and 1467 parts by weight of tung oil to the reactor and continue stirring for 10 minutes.

[0161] (6) Add 17 parts by weight of methanol and 17 parts by weight of p-toluenesulfonic acid to the standby reaction vessel and stir until completely dissolved;

[0162] (7) Following the reaction in step (5), add 30 parts by weight of the product obtained in the prepared reaction vessel in step (6) to step (5) and continue stirring for 10 minutes.

[0163] (8) Raise the temperature to 90±2℃ and start timing. Keep the temperature at 90±2℃ for 120 minutes and continue stirring.

[0164] (9) Add 12 parts by weight of water and 12 parts by weight of triethanolamine to the standby reactor and continue stirring for 10 minutes;

[0165] (10) Following the reaction in step (8), add 25 parts by weight of the product obtained in the prepared reaction vessel in step (9) to step (8), continue stirring for 10 minutes, and begin cooling to 60°C.

[0166] (11) Next, add 3056 parts by weight of formaldehyde to the reactor in step (10) and continue stirring for 10 minutes;

[0167] (12) Next, add 40 parts by weight of ammonia water and 79 parts by weight of triethylamine to the reactor in step (11), and continue stirring for 10 minutes.

[0168] (13) Raise the temperature to 95±2℃ and start timing. Control the temperature at 95±2℃ and maintain it for 20 minutes. Continue stirring. Start sampling to determine GT. After reaching the standard, start vacuum dehydration and start timing. Slowly increase the vacuum degree. When the temperature drops to 70±2℃, heat it. Grind it until GT reaches the standard. Start cooling to 50℃ and continue stirring.

[0169] (14) Next, in step (13), 600 parts by weight of B glue and 4033 parts by weight of methanol obtained in step (4) are added to the reactor to obtain tung oil modified phenolic resin.

[0170] S202: Add 2000 parts by weight of epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin, 1000 parts by weight of polyhydroxycyanamide resin, 2000 parts by weight of thermosetting phenolic resin, and 2000 parts by weight of tung oil modified phenolic resin to the reactor, and continue stirring for 60 minutes.

[0171] S203: Next, add 1500 parts by weight of 128 epoxy resin to the reactor of S202 and continue stirring for 30 minutes.

[0172] S204: Next, add 200 parts by weight of titanium dioxide, 500 parts by weight of silica powder, and 200 parts by weight of aluminum hydroxide to the reactor of S203, and continue stirring for 30 minutes.

[0173] S205: Next, add 6 parts by weight of coupling agent KH-560 to the reaction vessel of S204, and continue stirring for 30 minutes before taking samples to determine GT.

[0174] S206: Next, take a sample from the reaction vessel in S205 to measure the GT value. Based on the measured GT value, add 6 parts by weight of imidazole and continue stirring.

[0175] S207: Next, 1600 parts by weight of methanol were added to the reactor of S206 to obtain halogen-free paper-based adhesive.

[0176] The halogen-free paper-based adhesive prepared in this embodiment was impregnated with 135g / m 2Bleached wood pulp paper is dried in an oven at 115-220℃. The pre-impregnated material is heated in the oven for 2-5 minutes, resulting in a paper-based prepreg with a thickness of 150-250μm and a volatile content of 3-5%. The prepreg is pressed at 0.7±0.2MPa for 6 minutes, achieving a flowability of 4.5-6.5%. It is then dried and cut into the required dimensions. A cloth-based adhesive is prepared and used for applying to electronic-grade fiberglass cloth to obtain a cloth-based prepreg. Six paper-based prepregs are stacked with two cloth-based prepregs and a 25μm uncoated copper foil. The stacked pieces are then pressed in a hot press for 110-190 minutes, with the pressing conditions gradually increasing from 0 to 0.85MPa and 120-190℃, resulting in a 1.6mm thick composite paper-based copper-clad laminate.

[0177] Comparative Example 1

[0178] S100: Preparation of modified melamine resin;

[0179] S200: Preparation of thermosetting phenolic resin;

[0180] S300: Used to prepare thermosetting phenolic epoxy resin, i.e., to prepare cloth-based adhesive;

[0181] S400: The prepared cloth-based adhesive is used for applying adhesive to electronic-grade fiberglass cloth to obtain a cloth-based prepreg.

[0182] S500: Preparation of modified thermoplastic nonylphenol aldehyde resin:

[0183] S510: Add 686 parts by weight of phenol, 935 parts by weight of formaldehyde and 250 parts by weight of nonylphenol to the reactor and stir.

[0184] S520: Add 42 parts by weight of ammonia water and 4.28 parts by weight of triethylamine mixed catalyst to the reactor and continue stirring;

[0185] S530: Raise the temperature to 88±2℃ and start timing. Control the temperature at 90-94℃ and maintain it for 120±20 minutes. Control the gelation time at 160±10s. Start vacuum dehydration until the resin gelation time is controlled at 120±5s.

[0186] S540: Add 748 parts by weight of methanol to the obtained product to obtain modified thermoplastic nonylphenol resin.

[0187] S600: Preparation of paper-based adhesives:

[0188] S610: Add 300 parts by weight of modified melamine resin, 2000 parts by weight of thermosetting phenolic resin, and 2000 parts by weight of modified thermoplastic nonylphenolic resin to the reactor and stir.

[0189] S620: Add 1600 parts by weight of epoxy resin 901, 750 parts by weight of low-bromine epoxy resin, 250 parts by weight of cashew phenol resin T10, and 300 parts by weight of triphenyl phosphate to the reactor, and continue stirring.

[0190] S630: Add 750 parts by weight of flame retardant 530, 250 parts by weight of tetrabromobisphenol A, 350 parts by weight of magnesium hydroxide, 100 parts by weight of antimony trioxide, 500 parts by weight of silica powder, and 125 parts by weight of titanium dioxide to the reactor, and continue stirring.

[0191] S640: Add 190 parts by weight of toluene and 1750 parts by weight of methanol solvent to the reactor for dilution, and continue stirring;

[0192] S650: Based on the detected gelation time, add 1 part by weight of dimethylimidazole to the reactor for catalytic reaction and continue stirring to obtain bisphenol A modified thermoplastic phenolic epoxy resin.

[0193] The bisphenol A modified thermoplastic phenolic epoxy resin prepared in this embodiment is impregnated with 135 g / m2 of bleached wood pulp paper. The temperature in the oven is 115-210℃, and the pre-impregnated body is heated in the oven for 2-5 minutes. The thickness of the resulting semi-cured sheet is 150-250 μm, and the volatile matter of the semi-cured sheet is 3-5%. It is pressed at 0.7±0.2 MPa for 6 minutes, and the flowability is 4.5-6.5%. It is dried into a semi-cured sheet and cut into the required size. The obtained 6 paper-based semi-cured sheets are stacked with two cloth-based semi-cured sheets and one uncoated copper foil, and then pressed in a hot press for 110-190 minutes. The pressing conditions are 0 to 0.85 MPa and 120-190℃, which yields a 1.6 mm thick paper-based composite copper-clad laminate.

[0194] Comparative Example 2

[0195] The difference between Comparative Example 2 and Example 1 lies in the following steps:

[0196] S202: Add 2000 parts by weight of epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin, 1000 parts by weight of polyhydroxycyanamide resin, 1000 parts by weight of thermosetting phenolic resin, and 2000 parts by weight of tung oil modified phenolic resin to the reactor, and continue stirring for 60 minutes.

[0197] Apart from the aforementioned distinguishing steps, the steps in Comparative Example 2 are the same as those in Example 1.

[0198] Comparative Example 3

[0199] The difference between Comparative Example 3 and Example 1 lies in the following steps:

[0200] S202: Add 2000 parts by weight of epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin, 1000 parts by weight of polyhydroxycyanamide resin, 2000 parts by weight of thermosetting phenolic resin, and 1000 parts by weight of tung oil modified phenolic resin to the reactor, and continue stirring for 60 minutes.

[0201] Apart from the aforementioned distinguishing steps, the steps in Comparative Example 3 are the same as those in Example 1.

[0202] Comparative Example 4

[0203] The difference between Comparative Example 4 and Example 1 lies in the following steps:

[0204] S202: Add 1000 parts by weight of epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin, 1000 parts by weight of polyhydroxycyanamide resin, 2000 parts by weight of thermosetting phenolic resin, and 2000 parts by weight of tung oil modified phenolic resin to the reactor, and continue stirring for 60 minutes.

[0205] Apart from the aforementioned distinguishing steps, the steps in Comparative Example 4 are the same as those in Example 1.

[0206] Comparative Example 5

[0207] The difference between Comparative Example 5 and Example 1 lies in the following steps:

[0208] Delete S201: Preparation of tung oil modified phenolic resin (including steps (1)-(14));

[0209] S202: Add 1000 parts by weight of epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin, 1000 parts by weight of polyhydroxycyanamide resin, and 2000 parts by weight of thermosetting phenolic resin to the reactor, and continue stirring for 60 minutes.

[0210] S205: Next, add 7 parts by weight of coupling agent KH-560 to the reaction vessel of S204, and continue stirring for 30 minutes before taking samples to determine GT.

[0211] S206: Next, take a sample from the reaction vessel in S205 to measure the GT value. Based on the measured GT value, add 8 parts by weight of imidazole and continue stirring.

[0212] Apart from the aforementioned distinguishing steps, the steps in Comparative Example 5 are the same as those in Example 1.

[0213] Comparative Example 6

[0214] The difference between Comparative Example 6 and Example 1 lies in the following steps:

[0215] Remove S100: Steps for preparing epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin (including S101-S105);

[0216] S202: Add 1000 parts by weight of polycyanamide resin, 2000 parts by weight of thermosetting phenolic resin, and 2000 parts by weight of tung oil modified phenolic resin to the reactor, and continue stirring for 60 minutes.

[0217] S205: Next, add 4 parts by weight of coupling agent KH-560 to the reaction vessel of S204, and continue stirring for 30 minutes before taking samples to determine GT.

[0218] S206: Next, take a sample from the reaction vessel in S205 to measure the GT value. Based on the measured GT value, add 3 parts by weight of imidazole and continue stirring.

[0219] Apart from the aforementioned distinguishing steps, the steps in Comparative Example 6 are the same as those in Example 1.

[0220] Comparative Example 7

[0221] The difference between Comparative Example 7 and Example 1 lies in the following steps:

[0222] S202: Add 2000 parts by weight of epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin, 2000 parts by weight of thermosetting phenolic resin, and 2000 parts by weight of tung oil modified phenolic resin to the reactor, and continue stirring for 60 minutes.

[0223] S205: Next, add 5 parts by weight of coupling agent KH-560 to the reaction vessel of S204, and continue stirring for 30 minutes before taking samples to determine GT.

[0224] S206: Next, take a sample from the reaction vessel in S205 to measure the GT value. Based on the measured GT value, add 4 parts by weight of imidazole and continue stirring.

[0225] Apart from the aforementioned distinguishing steps, the steps in Comparative Example 7 are the same as those in Example 1.

[0226] Examples 1 and Comparative Examples 1-7 were subjected to halogen, triphenyl phosphate, heat resistance, peel strength, appearance requirements, and material cost tests. The vertical burning rating, thermal stress, and peel resistance were tested according to the provisions of GB / T 4721-2021, GB / T4722-2017, and GB / T 4724-2017. The specific results are shown in Table 1.

[0227] Table 1. Test results of the composite paper-based copper-clad laminates prepared in Example 1 and Comparative Examples 1-7

[0228]

[0229] Comparative Example 1 is a halogenated 22F. As can be seen from Table 1, compared with Comparative Example 1, Example 1 of this application has a vertical combustion rating of FV-0 and similar peel strength. Although Comparative Example 1 has a higher effective total combustion time and thermal stress and lower cost than Example 1, the halogenated 22F of Comparative Example 1 has a much higher halogen and triphenyl phosphate content than Example 1, which poses the problem of environmental pollution and threats to human health.

[0230] Comparative Examples 2-7 are related comparative examples set up based on Example 1 of this application. The main difference lies in the difference in the formulation and dosage of the halogen-free paper-based adhesive. Through comparison, it can be seen that when the cost difference is not significant, the overall comprehensive performance of Example 1 is better than that of Comparative Examples 2-7. Under the same halogen-free property, Example 1 can take into account the product performance such as vertical burning rating, thermal stress, peel strength and effective total burning time, while Comparative Examples 2-7 cannot achieve the performance indicators that are taken into account. The comparison results show that Example 1 of this application is the composite paper-based copper-clad laminate product that best meets the requirements of market use.

[0231] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention shall fall within the scope of the claims of the present invention.

Claims

1. A method for manufacturing a halogen-free paper-based adhesive, characterized in that, Includes the following steps: S201: Preparation of epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin; the manufacturing method includes the following steps S101-S105. S101: Add 3300-4900 parts by weight of 128 epoxy resin and 750-1150 parts by weight of phosphorus-containing halogen-free flame retardant to the standby reactor, and stir continuously. Heat to 150℃ and hold at that temperature for 120 minutes. Cool to 50℃ and set aside the resulting A glue. Continue stirring. The phosphorus-containing halogen-free flame retardant used is XS-EP-10 phosphorus-containing halogen-free flame retardant, with a phosphorus content ≥13%, a nitrogen content ≥5.8%, a water content ≤0.5%, and a relative density of 1.6-1.9 g / cm³. S102: Add 800-1200 parts by weight of phenol, 900-1350 parts by weight of paraformaldehyde, 600-900 parts by weight of methanol, and 600-900 parts by weight of melamine to the reactor, and continue stirring for 10 minutes. S103: Next, add 6-13 parts by weight of ethylenediamine catalyst to the reactor of S102 and continue stirring for 10 minutes; S104: Raise the temperature to 90±2℃ and start timing, control the temperature at 90-94℃ and maintain it for 60 minutes, then cool it to 50℃; S105: Add 1150-1750 parts by weight of methanol as a neutralizing agent and 4050-6050 parts by weight of A glue produced by S101 to the product obtained in S104. Heat to 90±2℃ and start timing. Control the temperature at 90-94℃ and maintain for 60 minutes. Cool to 50℃ to obtain epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin. S202: Add 1600-2400 parts by weight of epoxy resin modified nitrogen-phosphorus phenolic flame retardant resin, 800-1200 parts by weight of polyhydroxycyanamide resin, 1600-2400 parts by weight of thermosetting phenolic resin, and 1600-2400 parts by weight of tung oil modified phenolic resin to the reactor, and continue stirring for 60 minutes. S203: Next, add 1200-1800 parts by weight of 128 epoxy resin to the reactor of S202 and continue stirring for 30 minutes; S204: Next, add 150-250 parts by weight of titanium dioxide, 400-600 parts by weight of silica powder, and 150-250 parts by weight of aluminum hydroxide to the reactor of S203, and continue stirring for 30 minutes. S205: Next, add 4-10 parts by weight of coupling agent KH-560 to the reaction vessel of S204, and continue stirring for 30 minutes before taking samples to determine GT. S206: Next, take a sample from the reaction vessel in S205 to measure the GT value. Based on the measured GT value, add 3-8 parts by weight of imidazole and continue stirring. S207: Next, 1300-1950 parts by weight of methanol are added to the reactor of S206 to obtain halogen-free paper-based adhesive.

2. The method for manufacturing a halogen-free paper-based adhesive as described in claim 1, characterized in that, In step S202, the preparation method of the thermosetting phenolic resin is as follows: (1) Add 2600-3850 parts by weight of phenol, 2100-3150 parts by weight of formaldehyde and 10-20 parts by weight of oxalic acid in sequence, and stir for 10 minutes; (2) Heat to 70-75℃ and then turn off the heating; when the temperature reaches 85-90℃, start turning on the water to control the temperature; (3) Heat to 90℃ and start recording the reaction time. Keep the temperature at 95±2℃ for the reaction. (4) Start observing the resin reaction after 25 minutes of heat preservation reaction. The normal emulsification point time is 35 minutes. (5) After the resin reaction emulsifies for 80-90 minutes, and the total reaction time is 120 minutes, dehydration begins. Heating begins after the temperature drops to 70℃. Vacuum sampling is stopped when the temperature rises back to 70℃. (6) Then add 1800-2650 parts by weight of methanol as solvent and stir for 1 hour. When the temperature cools down to below 50°C, take a sample and send it for testing; to obtain thermosetting phenolic resin.

3. A method for manufacturing a halogen-free composite paper-based copper-clad laminate, characterized in that, Includes the following steps: S301: A method for preparing a halogen-free paper-based adhesive according to any one of claims 1-2; S302: Preparation of halogen-free paper-based prepreg: The obtained halogen-free paper-based adhesive is used for gluing wood pulp paper to obtain a paper-based prepreg. S303: Preparation of fabric-based adhesive; S304: The prepared cloth-based adhesive is used for applying adhesive to electronic-grade fiberglass cloth to obtain a cloth-based prepreg. S305: Preparation of halogen-free copper clad laminate: Sequentially stack one cloth-based prepreg, six paper-based prepregs, one cloth-based prepreg, and one uncoated copper foil, and press them by controlling the temperature and pressure of a hot press to obtain a halogen-free composite paper-based copper clad laminate.

4. The method for manufacturing a halogen-free composite paper-based copper-clad laminate as described in claim 3, characterized in that, The specific steps of S302 are as follows: halogen-free paper-based adhesive is used to impregnate 130-155 g / m² of bleached wood pulp paper. The temperature in the oven is 115-220℃, and the pre-impregnated body is heated in the oven for 2-5 minutes. The thickness of the resulting semi-cured sheet is 150-250 µm, the volatile matter content of the semi-cured sheet is 3-5%, it is pressed at 0.7±0.2 MPa for 6 minutes, the flowability is 4.5-6.5%, and it is dried into a semi-cured sheet and cut into the required size to produce a paper-based semi-cured sheet.

5. The method for manufacturing a halogen-free composite paper-based copper-clad laminate as described in claim 3, characterized in that, The specific steps of S304 are as follows: the halogen-free cloth-based adhesive is impregnated with electronic-grade glass fiber cloth at a temperature of 105-210 g / m², the temperature in the oven is 100-220℃, the pre-impregnated body is heated in the oven for 4-10 min, the thickness of the resulting semi-cured sheet is 140-230µm, the volatile matter of the semi-cured sheet is ≤0.5%, the semi-cured sheet is dried and cut into the required size to make a cloth-based semi-cured sheet.

6. The method for manufacturing a halogen-free composite paper-based copper-clad laminate as described in claim 3, characterized in that, In S305, the hot press is pressed for 100-190 minutes. The pressing conditions are as follows: the pressure is gradually increased from 0 MPa to 2 MPa in the first 5 minutes, and then gradually increased from 2 MPa to 8.5 MPa. The hot pressing temperature is 120-190℃, resulting in a 1.6mm thick paper-based composite copper-clad laminate.

7. The method for manufacturing a halogen-free composite paper-based copper-clad laminate as described in claim 3, characterized in that, The specific steps of S303 are as follows: (1) Add 40-60 parts by weight of benzoxazine resin, 40-60 parts by weight of reactive phosphazene compound, 40-60 parts by weight of polyacrylic acid, 40-60 parts by weight of epoxy resin halogen-free flame retardant, and 310-460 parts by weight of phosphorus-containing epoxy resin in sequence, and continue stirring for 30 minutes. (2) Next, add 40-60 parts by weight of solid phenolic resin and 160-240 parts by weight of acetone, and continue stirring for 30 minutes. (3) Next, add 60-90 parts by weight of silica powder and 30-40 parts by weight of aluminum hydroxide, and continue stirring for 30 minutes; (4) Next, add 60-90 parts by weight of melamine cyanurate SX-MC-15 and 0.5-2 parts by weight of coupling agent KH-560, and continue stirring for 20 minutes; (5) Next, add 0.5-1.5 parts by weight of Brilliant Yellow and continue stirring for 30 minutes. Then, start taking samples to determine GT. (6) Next, according to the measured GT value, add 0.2-0.6 parts by weight of imidazole and continue stirring to obtain halogen-free cloth-based adhesive.

Images