Laminated board and preparation method thereof

Abstract

The invention discloses a laminated board and a preparation method thereof. The preparation method of the laminated board comprises the following steps: (1) coating a reinforcing material with a glue solution, and drying to obtain a prepreg; the raw materials of the glue solution comprise resin, a curing agent, a curing accelerator, a coupling agent and a solvent, and optionally, the raw materials also comprise an inorganic filler; and (2) superposing more than two prepregs, and performing hot pressing to obtain the laminated board, the hot pressing process sequentially comprises a first stage, a second stage and a third stage. According to the preparation process of the laminated board, the interlayer binding force and the overall uniformity of the copper-clad plate can be improved, the defects such as bubbles and gaps are reduced, and the quality stability of the product is improved.

Description

Technical Field

[0001] The invention relates to a laminate and a preparation method thereof. Background Art

[0002] In the production process of electronic circuit products, the preparation of copper clad laminate is an important link. Common methods for preparing copper clad laminates include calendering, electrolytic deposition and prepreg.

[0003] Among them, the calendering method has a high cost and the uniformity of the copper foil thickness is difficult to control; the electrolytic deposition method has a complicated process and is prone to defects such as pinholes and pitting that affect conductivity; the semi-cured sheet method is currently the most commonly used method.

[0004] However, the semi-cured sheet method has high requirements on the pressing process, otherwise the copper clad laminate is prone to bubbles and delamination, which will also lead to poor mechanical properties.

[0005] Therefore, providing a method for preparing a laminate with stable process and excellent comprehensive performance of the laminate is a technical problem to be solved urgently in the field. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the prior art that the preparation process of the laminate is complicated and it is difficult to ensure the performance of the laminate, and to provide a laminate and a preparation method thereof.

[0007] The present invention provides a method for preparing a laminate, which comprises the following steps:

[0008] (1) applying a glue solution to a reinforcing material and drying the solution to obtain a prepreg; the raw materials of the glue solution include a resin, a curing agent, a curing accelerator, a coupling agent and a solvent, and optionally, the raw materials also include an inorganic filler;

[0009] (2) stacking two or more prepregs and hot pressing them to obtain the laminate;

[0010] The hot pressing process includes stage one, stage two, and stage three in sequence, wherein:

[0011] In the first stage, the vacuum value is 740-760 mmHg, the temperature at the start of hot pressing is 110-130°C, and the pressure at the start of hot pressing is 5-10 kg / cm 2 The temperature at the end of hot pressing is 200-220℃, and the pressure at the end of hot pressing is 25-30 kg / cm 2 , the hot pressing time is 50-60min;

[0012] In the second stage, the vacuum value is 740-760 mmHg, the temperature of hot pressing is 200-220°C, and the pressure of hot pressing is divided into initial pressure, intermediate pressure and late pressure; the initial pressure is 25-30 kg / cm 2 The initial pressure pressing time is 10-15 min; the intermediate pressure is 35-40 kg / cm 2 The mid-term pressure pressing time is 35-40min; the late pressure is 20-25kg / cm 2 The time of the late pressure pressing is 10-15 min;

[0013] The third stage: vacuum or non-vacuum conditions, the temperature at the start of hot pressing is 200-220°C, and the pressure at the start of hot pressing is 20-25 kg / cm 2 The temperature at the end of hot pressing is 110-130℃, and the pressure at the end of hot pressing is 30-35kg / cm 2 The hot pressing time is 20-40min.

[0014] In the present invention, the starting temperature used in the first stage is 110-130°C (for example, 120°C), which is 50°C-90°C higher than the traditional temperature in the industry. This can improve production efficiency, improve the fluidity and wettability of the resin in the raw materials, help improve the interlayer bonding strength and overall uniformity of the copper clad laminate, reduce defects such as bubbles and voids, and improve the quality stability of the product.

[0015] In some embodiments of the present invention, in the stage one, the vacuum value is 740-750 mmHg.

[0016] In some embodiments of the present invention, in the stage 1, the temperature at the starting point of the hot pressing is 120°C.

[0017] In some embodiments of the present invention, in the first stage, the pressure at the start of the hot pressing is 5 kg / cm 2 or 10kg / cm 2 .

[0018] In some embodiments of the present invention, in the stage 1, the temperature at the end point of the hot pressing is 210°C.

[0019] In some embodiments of the present invention, in the first stage, the pressure at the end of the hot pressing is 25 kg / cm 2 or 30 kg / cm 2 .

[0020] In some embodiments of the present invention, in the stage 1, the hot pressing time is 55 min.

[0021] In the present invention, in the first stage, the temperature of the hot pressing can be increased linearly or nonlinearly.

[0022] In some embodiments of the present invention, in the first stage, the temperature of the hot pressing is linearly increased from 110-130° C. to 200-220° C. within a time range of 50-60 min.

[0023] In some embodiments of the present invention, in the stage 1, the heating rate of hot pressing is 1.00-2.00° C. / min, for example, 1.63° C. / min.

[0024] In the present invention, in the first stage, the pressure of the hot pressing can be increased linearly or nonlinearly.

[0025] In some embodiments of the present invention, in the first stage, the pressure of the hot pressing is within the range of 50-60 min, from 4-6 kg / cm 2 Increase linearly to 25-30 kg / cm 2 .

[0026] In some embodiments of the present invention, in the first stage, the pressure increase rate of the hot pressing is 0.10-0.50 kg / cm 2 / min, for example 0.36 kg / cm 2 / min.

[0027] In the present invention, the hot pressing temperature used in the second stage is 200-220°C (for example, 210°C): during the hot pressing process, at this temperature, the resin molecules begin to undergo a cross-linking reaction and gradually form a stable three-dimensional network structure, thereby achieving curing and giving the copper clad laminate the required physical and chemical properties.

[0028] In the present invention, the pressure setting is divided into stages in the second stage, and 25-30 kg / cm is applied in the initial stage. 2 The pressure is increased to 35-40 kg / cm 2 At higher pressure, the resin can better infiltrate the reinforcing material (such as glass fiber cloth), fill the gaps, and ensure a close bond between the layers; finally, reduce the pressure to 20-25 kg / cm 2 This is to avoid damage to the already formed structure caused by excessive pressure in the later stage of resin curing, and it also helps to release the stress of the product.

[0029] In some embodiments of the present invention, in the second stage, the vacuum value is 740-750 mmHg.

[0030] In some embodiments of the present invention, in the second stage, the temperature of hot pressing is 210°C.

[0031] In some embodiments of the present invention, in the second stage, the initial pressure is 25 kg / cm 2 or 30 kg / cm 2 .

[0032] In some embodiments of the present invention, in the second stage, the initial pressure pressing time is 10 minutes or 15 minutes.

[0033] In some embodiments of the present invention, in the second stage, the intermediate pressure is 35 kg / cm 2 or 40 kg / cm 2 .

[0034] In some embodiments of the present invention, in the second stage, the duration of the mid-term pressure pressing is 35 minutes or 40 minutes.

[0035] In some embodiments of the present invention, in the second stage, the later pressure is 20 kg / cm 2 or 25 kg / cm 2 .

[0036] In some embodiments of the present invention, in the second stage, the time of the later pressure pressing is 15 minutes.

[0037] In one embodiment of the present invention, in the second stage, the vacuum value is 740-760 mmHg, the hot pressing temperature is 210°C; the initial pressure is 25 kg / cm 2 The initial pressure pressing time is 10 min; the intermediate pressure is 35 kg / cm 2 The mid-term pressure pressing time is 35 min; the late pressure is 20 kg / cm 2 The time of the later pressure pressing is 15 min.

[0038] In one embodiment of the present invention, in the second stage, the vacuum value is 740-760 mmHg, the hot pressing temperature is 210°C; the initial pressure is 30 kg / cm 2 The initial pressure pressing time is 10 min; the intermediate pressure is 40 kg / cm 2 The mid-term pressure pressing time is 35 min; the late pressure is 25kg / cm 2 The time of the later pressure pressing is 15 min.

[0039] In one embodiment of the present invention, in the second stage, the vacuum value is 740-760 mmHg, the hot pressing temperature is 210°C; the initial pressure is 25 kg / cm 2 The initial pressure pressing time is 15min; the intermediate pressure is 35kg / cm 2 The mid-term pressure pressing time is 40 minutes; the late pressure is 20 kg / cm 2 The time of the later pressure pressing is 15 min.

[0040] In the present invention, the pressing is performed under the condition of a vacuum value of 740-760 mmHg in the first and second stages, which can prevent air and volatiles from entering the plate during the hot pressing process and avoid the formation of defects such as bubbles and gaps inside the plate.

[0041] In the present invention, the resin curing reaction in the third stage has been basically completed, and the internal structure of the board has been relatively stable, and vacuum or non-vacuum conditions can be used. As the temperature decreases from 200-220°C (for example, 210°C) to 110-130°C (for example, 120°C), the physical and chemical changes inside the material gradually stabilize, and it is no longer necessary to use a vacuum environment to promote the discharge of volatiles or ensure the flow of resin. In the third stage, hot pressing under the condition of stopping vacuuming can cool the board in a relatively normal pressure environment, which is more conducive to the uniform release of internal stress of the material and the stability of the structure.

[0042] In the present invention, the hot pressing process in the third stage can:

[0043] 1. Enhance interlayer bonding: In the final stage of hot pressing, appropriately increasing the pressure can further enhance the bonding between the layers of the copper clad laminate; improve interlayer adhesion, prevent defects such as interlayer separation, and thus improve the overall performance of the copper clad laminate;

[0044] 2. Promote structural densification: The increase in pressure helps to promote the densification of the internal structure of the copper clad laminate. At high temperatures, there may be some tiny gaps or defects inside the material. As the pressure increases, these gaps will be further compressed, and the material structure will be denser, thereby improving the strength, hardness and insulation performance of the copper clad laminate.

[0045] 3. Compensate for resin shrinkage: During the cooling process, the resin will shrink, which may cause some tiny gaps or uneven stress inside the copper clad laminate. Increasing the pressure can compensate for the shrinkage of the resin to a certain extent, maintain the stability of the internal structure of the copper clad laminate, make the bonding between the layers more firm, and avoid the adverse effects caused by resin shrinkage.

[0046] In some embodiments of the present invention, in the stage three, hot pressing is performed under the condition of stopping vacuuming.

[0047] In some embodiments of the present invention, in the stage three, the temperature at the starting point of the hot pressing is 210°C.

[0048] In some embodiments of the present invention, in the third stage, the pressure at the start of the hot pressing is 20 kg / cm 2 .

[0049] In some embodiments of the present invention, in the stage three, the temperature at the end point of the hot pressing is 120°C.

[0050] In some embodiments of the present invention, in the third stage, the pressure at the end of the hot pressing is 30 kg / cm 2 .

[0051] In some embodiments of the present invention, in the stage three, the hot pressing time is 30 min.

[0052] In the present invention, in the third stage, the temperature of the hot pressing can be reduced linearly or nonlinearly.

[0053] In some embodiments of the present invention, in the third stage, the temperature of the hot pressing is linearly reduced from 200-220° C. to 110-130° C. within a time range of 20-40 min.

[0054] In some embodiments of the present invention, in the stage three, the cooling rate of the hot pressing is 2.00-4.00°C / min, for example, 3.00°C / min.

[0055] In the present invention, in the third stage, the pressure of the hot pressing can be increased linearly or nonlinearly.

[0056] In some embodiments of the present invention, in the third stage, the pressure of the hot pressing is 20-40min, from 20-25kg / cm 2 Increase linearly to 30-35 kg / cm 2 .

[0057] In some embodiments of the present invention, in the third stage, the pressure increase rate of the hot pressing is 0.10-0.50 kg / cm 2 / min, for example 0.33 kg / cm 2 / min.

[0058] In some embodiments of the present invention, the solvent includes a mixed solvent 1 and a mixed solvent 2, wherein the mixed solvent 1 is a solvent that can dissolve the curing agent, the curing accelerator and part of the inorganic filler, and the mixed solvent 2 is a solvent that can dissolve the coupling agent and the resin.

[0059] In some embodiments of the present invention, the mixed solvent 1 includes DMF (N,N-dimethylformamide), ethanol, dimethyl sulfoxide (DMSO), and γ-butyrolactone (GBL). The mass ratio of DMF, ethanol, dimethyl sulfoxide, and γ-butyrolactone can be (4-6): (2-4): 1:1, for example 5:3:1:1.

[0060] In some embodiments of the present invention, the mixed solvent 2 comprises propylene glycol methyl ether (PM), ethyl acetate, and isopropanol, and the mass ratio of propylene glycol methyl ether, ethyl acetate, and isopropanol can be (4-6): (2-4): 2, for example, 5:3:2.

[0061] In some embodiments of the present invention, the mass fraction of the mixed solvent 1 is 450-550 parts, for example, 500 parts.

[0062] In some embodiments of the present invention, the mass fraction of the mixed solvent 2 is 135-165 parts, for example, 150 parts.

[0063] In some embodiments of the present invention, the mass fraction of the mixed solvent 2 is 765-935 parts, for example, 850 parts.

[0064] In some embodiments of the present invention, the raw materials of the glue solution include the following component A:

[0065] 360-440 parts of bisphenol A epoxy resin, wherein the bisphenol A epoxy resin has an epoxy equivalent of 185-190 g / eq and a viscosity of 12000-15000 mPa·s at 25° C.;

[0066] 1260-1540 parts of a DOPO-modified phosphorus-containing epoxy resin, wherein the DOPO-modified phosphorus-containing epoxy resin has an epoxy equivalent of 295-335 g / eq;

[0067] 180-220 parts of bisphenol A novolac epoxy resin, wherein the epoxy equivalent of the bisphenol A novolac epoxy resin is 190-220 g / eq;

[0068] 90-110 parts of a novolac epoxy resin, wherein the novolac epoxy resin has an epoxy equivalent of 176-181 g / eq;

[0069] 270-330 parts of bisphenol A type phosphorus-containing phenolic resin, wherein the viscosity of the bisphenol A type phosphorus-containing phenolic resin at 25° C. is 500-2500 mPa.s;

[0070] 90-110 parts of a tetrafunctional novolac epoxy resin, wherein the epoxy equivalent of the tetrafunctional novolac epoxy resin is 200-220 g / eq;

[0071] 450-550 parts of the mixed solvent 1, 135-165 parts of the mixed solvent 2;

[0072] 0.5-1.5 parts of curing accelerator;

[0073] 18-22 parts of silane coupling agent;

[0074] Optionally, the raw material further comprises an inorganic filler.

[0075] In some embodiments of the present invention, the bisphenol A epoxy resin may be NPEL128E produced by Kunshan Nan Ya.

[0076] In some embodiments of the present invention, the solid content of the bisphenol A epoxy resin is 100%.

[0077] In some embodiments of the present invention, the mass fraction of the bisphenol A epoxy resin is 400 parts.

[0078] In some embodiments of the present invention, the DOPO-type modified phosphorus-containing epoxy resin may be DFE202 produced by Sichuan Dongcai.

[0079] In some embodiments of the present invention, the solid content of the DOPO-type modified phosphorus-containing epoxy resin is 70-80%, for example 75%.

[0080] In some embodiments of the present invention, the phosphorus content of the DOPO-type modified phosphorus-containing epoxy resin is 3.1-3.2%.

[0081] In some embodiments of the present invention, the mass fraction of the DOPO type modified phosphorus-containing epoxy resin is 1400 parts.

[0082] In some embodiments of the present invention, the bisphenol A novolac epoxy resin is SQAN-201EK80 produced by Shengquan.

[0083] In some embodiments of the present invention, the solid content of the bisphenol A novolac epoxy resin is 75-85%, for example 80%.

[0084] In some embodiments of the present invention, the mass fraction of the bisphenol A novolac epoxy resin is 200 parts.

[0085] In some embodiments of the present invention, the novolac epoxy resin may be DEN438 EK85J novolac epoxy resin produced by Dow.

[0086] In some embodiments of the present invention, the solid content of the phenolic epoxy resin is 80-90%, for example 85%.

[0087] In some embodiments of the present invention, the viscosity of the phenolic epoxy resin at 25° C. is 600-1600 mPa.s.

[0088] In some embodiments of the present invention, the mass fraction of the phenolic epoxy resin is 100 parts.

[0089] In some embodiments of the present invention, the bisphenol A type phosphorus-containing phenolic resin is XZ92741 produced by Dow.

[0090] In some embodiments of the present invention, the solid content of the bisphenol A type phosphorus-containing phenolic resin is 56-58%.

[0091] In some embodiments of the present invention, the phosphorus content of the bisphenol A type phosphorus-containing phenolic resin is 9-10%.

[0092] In some embodiments of the present invention, the mass fraction of the bisphenol A type phosphorus-containing phenolic resin is 300 parts.

[0093] In some embodiments of the present invention, the tetrafunctional phenolic epoxy resin is NPPN431A70 produced by Kunshan Nan Ya.

[0094] In some embodiments of the present invention, the solid content of the tetrafunctional phenolic epoxy resin is 65-75%, for example 70%.

[0095] In some embodiments of the present invention, the softening point of the tetrafunctional novolac epoxy resin is 82-92°C.

[0096] In some embodiments of the present invention, the mass fraction of the tetrafunctional phenolic epoxy resin is 100 parts.

[0097] In some embodiments of the present invention, the mass ratio of the bisphenol A epoxy resin, the DOPO modified phosphorus-containing epoxy resin, the bisphenol A novolac epoxy resin, the novolac epoxy resin, the bisphenol A phosphorus-containing novolac resin, and the tetrafunctional novolac epoxy resin is 4:14:2:1:3:1.

[0098] In some embodiments of the present invention, the mass fraction of the curing agent is 80 parts.

[0099] In some embodiments of the present invention, the curing agent is DDS (4,4'-diaminodiphenyl sulfone) and / or DICY (dicyandiamide).

[0100] In some embodiments of the present invention, the mass fraction of DICY (dicyandiamide) is 45-55 parts, for example, 50 parts.

[0101] In some embodiments of the present invention, the mass fraction of the DDS (4,4'-diaminodiphenyl sulfone) is 27-33 parts, for example, 30 parts.

[0102] In some embodiments of the present invention, the mass ratio of the DICY to the DDS is 5:3.

[0103] In some embodiments of the present invention, the curing accelerator is diphenylimidazole.

[0104] In some embodiments of the present invention, the mass fraction of the curing accelerator is 0.9-1.1 parts, for example, 1.0 parts.

[0105] In some embodiments of the present invention, the silane coupling agent is KH-570, and its chemical name is γ-methacryloxypropyltrimethoxysilane.

[0106] In some embodiments of the present invention, the mass fraction of the silane coupling agent is 20 parts.

[0107] In some embodiments of the present invention, the inorganic filler includes graphene oxide.

[0108] In some embodiments of the present invention, the mass fraction of the graphene oxide is 45-55 parts, for example, 50 parts.

[0109] In some embodiments of the present invention, the graphene oxide is a single layer.

[0110] In some embodiments of the present invention, the thickness of the graphene oxide is 0.8 nm-1.2 nm.

[0111] In some embodiments of the present invention, the specific surface area of ​​the graphene oxide is 500m² / g-1000m² / g.

[0112] In some embodiments of the present invention, the carbon-oxygen ratio of the graphene oxide is between 2-4.

[0113] In some embodiments of the present invention, the inorganic filler further includes spherical aluminum oxide and / or aluminum hydroxide.

[0114] The aluminum hydroxide in the present invention can be used as a flame retardant to reduce the decomposition of the material surface and the formation of carbon particles, thereby significantly improving the flame retardancy of the material and reducing the thermal expansion coefficient and water absorption rate of the plate.

[0115] In the present invention, the spherical alumina can effectively improve the thermal conductivity of the copper-clad laminate, accelerate heat dissipation, and reduce its dielectric constant and thermal expansion coefficient.

[0116] In some embodiments of the present invention, the sum of the mass fractions of the spherical aluminum oxide and / or aluminum hydroxide is 1080-1320 parts, for example, 1200 parts.

[0117] In some embodiments of the present invention, the mass fraction of the aluminum hydroxide is 900-1100 parts, for example, 1000 parts.

[0118] In some embodiments of the present invention, the grade of the aluminum hydroxide is MARTINAL® OL-104LEO.

[0119] In some embodiments of the present invention, the purity of the aluminum hydroxide is ≥99.6%, and the whiteness is ≥93.

[0120] In some embodiments of the present invention, the particle size range of the aluminum hydroxide is: D50, 1.9±0.2 μm; D90, 3.2±1.0 μm.

[0121] In some embodiments of the present invention, the oil absorption rate of the aluminum hydroxide is 27-32 ml / 100g.

[0122] In some embodiments of the present invention, the conductivity of the aluminum hydroxide (10%, in water) is: 20 μS / cm.

[0123] In some embodiments of the present invention, the mass fraction of the spherical aluminum oxide is 180-220 parts, for example, 200 parts.

[0124] In some embodiments of the present invention, the grade of the spherical alumina is SLA-5.

[0125] In some embodiments of the present invention, the D50 particle size of the spherical alumina is 5±1 μm.

[0126] In some embodiments of the present invention, the D90 particle size of the spherical alumina is 15±3 μm.

[0127] In some embodiments of the present invention, the mass ratio of the spherical aluminum oxide to the aluminum hydroxide is 1:5.

[0128] In some embodiments of the present invention, the mass fraction of the inorganic filler is 1125-1375 parts, for example, 1250 parts.

[0129] In some embodiments of the present invention, the composition of component A is shown in the following table:

[0130]

[0131] in:

[0132] Mixed solvent 1 refers to a mixed solvent of N,N-dimethylformamide DMF, ethanol, dimethyl sulfoxide DMSO, and γ-butyrolactone GBL in a mass ratio of 5:3:1:1;

[0133] The mixed solvent 2 refers to a mixed solvent in which propylene glycol methyl ether PM, ethyl acetate EA and isopropanol have a mass ratio of 5:3:2.

[0134] In some embodiments of the present invention, the method for preparing the adhesive for the halogen-free and antimony-free flame-retardant laminate comprises the following steps:

[0135] (1) Mixing the mixed solvent 1 (added according to each component), the curing agent (added according to each component), the curing accelerator and part of the inorganic filler (such as graphene oxide), and stirring until dissolved for 10-12 hours to obtain a mixture A;

[0136] (2) Mixing the mixture A with the coupling agent, the resin (added according to each component), and the mixed solvent 2 (added according to each component), and stirring for 1-2 hours to obtain a mixture B;

[0137] (3) Under stirring conditions, the mixture B and the remaining part of the inorganic filler (added according to each component) are mixed, and shear-ripened for 4-5 hours at a speed of 2000-2200 rpm and a glue temperature of 40-60°C, and then shear-ripened for 6-7 hours at a speed of 900-1100 rpm and a glue temperature of 45-50°C (total aging time is about 10-12 hours), and finally the halogen-free and antimony-free flame-retardant laminate glue is obtained.

[0138] In some embodiments of the present invention, the raw materials of the glue solution include the following component B:

[0139] 540-660 parts of bisphenol A epoxy resin, wherein the bisphenol A epoxy resin has an epoxy equivalent of 185-190 g / eq and a viscosity of 12000-15000 mPa·s at 25° C.;

[0140] 900-1100 parts of DOPO type modified phosphorus-containing epoxy resin, wherein the epoxy equivalent of the DOPO type modified phosphorus-containing epoxy resin is 295-335 g / eq;

[0141] 360-440 parts of solid bisphenol A epoxy resin, wherein the solid bisphenol A epoxy resin has an epoxy equivalent of 840-900 g / eq and a melt viscosity of 6000-9000 mPa·s at 150° C.;

[0142] 180-220 parts of MDI modified epoxy resin, wherein the epoxy equivalent of the MDI modified epoxy resin is 250-310 g / eq; and,

[0143] 450-550 parts of a linear bisphenol A formaldehyde resin, wherein the linear bisphenol A formaldehyde resin has a hydroxyl equivalent of 120-124 g / eq;

[0144] 450-550 parts of the mixed solvent 1, 765-935 parts of the mixed solvent 2;

[0145] 72-88 parts of curing agent;

[0146] 0.9-1.1 parts of curing accelerator;

[0147] 18-22 parts of a silane coupling agent; and,

[0148] Inorganic filler.

[0149] In some embodiments of the present invention, the mass fraction of the bisphenol A epoxy resin is 600 parts.

[0150] In some embodiments of the present invention, the bisphenol A epoxy resin may be NPEL128E produced by Kunshan Nan Ya.

[0151] In some embodiments of the present invention, the solid content of the bisphenol A epoxy resin may be 100%.

[0152] In some embodiments of the present invention, the mass fraction of the DOPO type modified phosphorus-containing epoxy resin is 1000 parts.

[0153] In some embodiments of the present invention, the DOPO-type modified phosphorus-containing epoxy resin may be DFE202 produced by Sichuan Dongcai.

[0154] In some embodiments of the present invention, the solid content of the DOPO-type modified phosphorus-containing epoxy resin may be 75%.

[0155] In some embodiments of the present invention, the phosphorus content of the DOPO-type modified phosphorus-containing epoxy resin may be 3.1-3.2%.

[0156] In some embodiments of the present invention, the mass fraction of the solid bisphenol A epoxy resin is 400 parts.

[0157] In some embodiments of the present invention, the solid bisphenol A epoxy resin may be medium molecular weight NPES-904H produced by Kunshan Nan Ya.

[0158] In some embodiments of the present invention, the 25° C. softening point of the solid bisphenol A epoxy resin may be 100-112.

[0159] In some embodiments of the present invention, the density of the solid bisphenol A epoxy resin at 25°C may be 1.18 g / cm 3 .

[0160] In some embodiments of the present invention, the mass fraction of the MDI-modified epoxy resin is 200 parts.

[0161] In some embodiments of the present invention, the MDI modified epoxy resin may be DFE205 produced by Sichuan Dongcai.

[0162] In some embodiments of the present invention, the solid content of the MDI modified epoxy resin may be 75%.

[0163] In some embodiments of the present invention, the mass fraction of the linear bisphenol A formaldehyde resin is 500 parts.

[0164] In some embodiments of the present invention, the linear bisphenol A formaldehyde resin may be SH-2130 produced by Shengquan Group.

[0165] In some embodiments of the present invention, the free bisphenol A content of the linear bisphenol A formaldehyde resin may be 13-17%.

[0166] In some embodiments of the present invention, the softening point of the linear bisphenol A formaldehyde resin may be 127-132°C.

[0167] In some embodiments of the present invention, the electrical conductivity of the linear bisphenol A formaldehyde resin may be ≤20 μs / cm.

[0168] In some embodiments of the present invention, the resin composition in component B may be the following composition:

[0169]

[0170] .

[0171] In some embodiments of the present invention, the method for preparing the glue solution comprises the following steps:

[0172] (1) Mixing the mixed solvent 1, the curing agent, the curing accelerator and a portion of the inorganic filler in the mixed solvent, and stirring until dissolved to obtain a mixture A;

[0173] (2) mixing the mixture A with the coupling agent, the resin, and the mixed solvent 2 in the mixed solvent, and stirring to obtain a mixture B;

[0174] (3) Under stirring conditions, the mixture B and the remaining part of the inorganic filler are mixed, and sheared and ripened to obtain the halogen-free and antimony-free flame-retardant laminate adhesive.

[0175] In some embodiments of the present invention, the stirring time in step (1) is 10-12 hours.

[0176] In some embodiments of the present invention, the stirring time in step (1) is 1-2 hours.

[0177] In some embodiments of the present invention, when the raw materials of the glue solution include the component A, the rotation speed of the shear ripening is 900-2200 rpm, such as 900-1100 rpm or 2000-2200 rpm.

[0178] In some embodiments of the present invention, when the raw materials of the glue solution include the component A, the shear aging temperature is 40-60°C, such as 45-50°C.

[0179] In some embodiments of the present invention, when the raw materials of the glue solution include the component A, the shear aging time is 10-12 hours.

[0180] In some embodiments of the present invention, when the raw materials of the glue solution include the component A, the shear ripening process is:

[0181] First, shear aging is performed at a speed of 2000-2200rpm and a glue temperature of 40-60℃ for 4-5 hours, and then shear aging is performed at a speed of 900-1100rpm and a glue temperature of 45-50℃ for 6-7 hours (the total aging time is about 10-12 hours).

[0182] In some embodiments of the present invention, when the raw materials of the glue solution include the component A, the gel time of the glue solution can reach 250-260 s.

[0183] In some embodiments of the present invention, when the raw materials of the glue solution include the component B, the rotation speed of the shear ripening is 900-1600 rpm, such as 900-1100 rpm or 1500-1600 rpm.

[0184] In some embodiments of the present invention, when the raw materials of the glue solution include the component B, the shear ripening temperature is 40-60°C, such as 45-50°C.

[0185] In some embodiments of the present invention, when the raw materials of the glue solution include the component B, the shear aging time is 18-22 hours.

[0186] In some embodiments of the present invention, when the raw materials of the glue solution include the component B, the shear ripening process is:

[0187] First, shear aging is performed at a speed of 1400-1600 rpm and a glue temperature of 40-50°C for 5-7 hours, and then shear aging is performed at a speed of 900-1100 rpm and a glue temperature of 40-50°C for 13-15 hours (the total aging time is about 18-22 hours).

[0188] In the present invention, the reinforcing material may be electronic grade glass fiber cloth or electronic glass fiber felt.

[0189] In the present invention, the laminated board may be a FR-4 board or a CEM-3 board.

[0190] In the present invention, FR-4 can be generally divided into FR-4.0 (ordinary board) and FR-4.1 (halogen-free board).

[0191] In the present invention, the FR-4.1 board uses electronic grade glass fiber cloth, such as 7628, 2116, 1080, etc. as a reinforcing material.

[0192] In the present invention, the CEM-3 board uses electronic glass fiber felt, such as 75g, 105g, 150g, and 200g of electronic glass fiber felt as a reinforcing material.

[0193] In the present invention, the prepregs generally do not require pressure when stacked, and the stacking requirements generally follow the four major principles in the field: the principle of matching high and low glue content, the principle of consistent layout, the principle of structural symmetry, and the principle of left and right matching.

[0194] In the present invention, different electronic glass fiber cloths can be selected according to different thicknesses, such as 8 7628 electronic glass fiber cloth semi-cured sheets are used for 1.5mm thick plates; 2*7628+2*1506+2*7628 are used for 1.1mm thick plates; and 2*7628+1*2116+2*7628 are used for 0.9mm thick plates.

[0195] In some embodiments of the present invention, the coating equipment is a vertical gluing machine.

[0196] In the present invention, the coating vehicle speed may be 15-20 m / min, such as 17 m / min or 16 m / min.

[0197] In the present invention, preferably, the drying temperature is 200-220°C, such as 210°C or 215°C.

[0198] In the present invention, the temperature of the glue solution may be 35-45°C, for example 40°C.

[0199] In the present invention, the resin content of the prepreg can reach 42-56%, such as 45% or 55-56%.

[0200] In the present invention, the gel time of the prepreg can reach 90-100s or 85-95s.

[0201] In the present invention, the fluidity of the prepreg can reach 20-28% or 26-32%.

[0202] In the present invention, the volatile matter of the prepreg may be ≤0.5%.

[0203] In some embodiments of the present invention, the reinforcing material is electronic grade glass cloth 7628, and the preparation process of the prepreg is:

[0204] The coating vehicle speed was 17 m / min.

[0205] The drying temperature is 210°C.

[0206] The temperature of the glue solution is 40°C.

[0207] In some embodiments of the present invention, the reinforcing material is electronic grade glass cloth 7628, and the properties of the prepreg are:

[0208] The mass content of the resin in the prepreg is 45%;

[0209] The gel time of the prepreg is 90-100s;

[0210] The fluidity of the prepreg is 20-28%;

[0211] The volatile matter of the prepreg is ≤0.5%.

[0212] In some embodiments of the present invention, the reinforcing material is electronic grade glass cloth 2116, and the preparation process of the prepreg is:

[0213] The coating speed is 16m / min;

[0214] The drying temperature is 215°C;

[0215] The temperature of the glue solution is 40°C.

[0216] In some embodiments of the present invention, the reinforcing material is electronic grade glass cloth 2116, and the properties of the prepreg are:

[0217] The mass content of the resin in the prepreg is 55-56%;

[0218] The gel time of the prepreg is 85-95s;

[0219] The fluidity of the prepreg can reach 26-32%;

[0220] The volatile matter of the prepreg is ≤0.5%.

[0221] In the present invention, one side or both sides of the prepreg may be covered with a metal foil or a release film.

[0222] In some embodiments of the present invention, the metal foil is copper foil.

[0223] The invention also provides a laminated board prepared by the method.

[0224] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0225] The reagents and raw materials used in the present invention are commercially available.

[0226] The positive and progressive effects of the present invention are:

[0227] (1) The preparation process of the laminated board of the present invention, the synergistic effect of the pressing temperature and the pressing pressure, helps to improve the interlayer bonding strength and overall uniformity of the copper clad board, reduce defects such as bubbles and gaps, and the board has a normal appearance, no texture leakage and copper wrinkles, etc., thereby improving the quality stability of the product.

[0228] (2) The flame-retardant laminate (FR-4.1 or CEM-3) with high thermal conductivity, CTI ≥ 600 V, TG ≥ 155°C, and halogen-free and antimony-free prepared by the preparation method of the present invention meets the production process requirements of the downstream printed circuit board (PCB) for the board material. The board material has good comprehensive performance, especially good thermal conductivity, CTI, flame retardancy, TG, and thickness uniformity. The thermal conductivity coefficient is high, and there is no delamination or blistering in the thermal stress test. DETAILED DESCRIPTION

[0229] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0230] In the following examples and comparative examples, the sources and descriptions of the raw materials are as follows:

[0231] DMF: N,N-dimethylformamide;

[0232] ETOH: ethanol;

[0233] DMSO: dimethyl sulfoxide;

[0234] GBL: gamma-butyrolactone;

[0235] DICY: dicyandiamide;

[0236] DDS: 4,4'-diaminodiphenyl sulfone;

[0237] Diphenylimidazole: 2-Phenylimidazole;

[0238] Graphene oxide: thickness is 0.8nm-1.2nm, single layer, specific surface area is 500m² / g-1000m² / g, carbon-oxygen ratio is between 2-4;

[0239] Silane coupling agent KH-570: γ-methacryloxypropyltrimethoxysilane;

[0240] Bisphenol A epoxy resin: NPEL128E produced by Kunshan Nan Ya, solid content 100%, epoxy equivalent 185-190g / eq, viscosity 12000-15000mPa·s at 25°C;

[0241] DOPO-type modified phosphorus-containing epoxy resin: DFE202 produced by Sichuan Dongcai, with a solid content of 75%, epoxy equivalent of 295-335g / eq, and a phosphorus content of 3.1-3.2%;

[0242] Bisphenol A novolac epoxy resin: SQAN-201EK80 produced by Shengquan, solid content 80%, epoxy equivalent 190-220g / eq;

[0243] Phenolic epoxy resin: DEN438 EK85J produced by Dow, solid content 85%, viscosity 600-1600mPa.s / 25℃, epoxy equivalent 176-181g / eq;

[0244] Bisphenol A type phosphorus-containing phenolic resin: XZ92741 produced by Dow, solid content 56-58%, viscosity 500-2500mPa.s / 25℃, phosphorus content 9-10%;

[0245] Tetrafunctional phenolic epoxy resin: NPPN431A70 produced by Kunshan Nan Ya, solid content 70%, epoxy equivalent 200-220g / eq, softening point: 82-92℃;

[0246] PM: propylene glycol methyl ether;

[0247] EA: ethyl acetate;

[0248] IPA: isopropyl alcohol;

[0249] Spherical alumina: SLA-5, D50 particle size is 5±1μm, D90 particle size is 15±3μm;

[0250] Aluminum hydroxide: MARTINAL® OL-104LEO, purity ≥99.6%, whiteness ≥93, particle size range: D50, 1.9±0.2μm; D90, 3.2±1.0μm; oil absorption rate: 27-32 ml / 100g; conductivity (10%, in water): 20μS / cm;

[0251] GEBR573K70 resin: purchased from Hongchang Electronic Materials Co., Ltd.;

[0252] YN3570K70 resin: purchased from Jiangsu Yangnong Jinhu Chemical Co., Ltd.;

[0253] 2-Methylimidazole: Its chemical name is 2-Methylimidezale, abbreviated as 2-MI.

[0254] The solid bisphenol A epoxy resin is medium molecular weight NPES-904H produced by Kunshan Nan Ya. Performance parameters: epoxy equivalent 840-900g / eq, softening point (25℃) 100-112, melt viscosity (150℃) 6000-9000mPa・s, density (25℃): 1.18 g / cm 3 .

[0255] The MDI modified epoxy resin is DFE205 produced by Sichuan Dongcai, with a solid content of 75% and an epoxy equivalent of 250-310.

[0256] Linear bisphenol A formaldehyde resin: SH-2130 produced by Shengquan Group, hydroxyl equivalent 120-124 g / eq, free bisphenol A 13-17%, softening point 127-132℃, conductivity ≤20μs / cm.

[0257] Magnesium hydroxide: purity ≥95%, whiteness ≥92, particle size range: D50, 4±1μm; conductivity (10%, in water): 40μs / cm.

[0258] Silicon dioxide: purity ≥99.5%, whiteness ≥90, particle size range: D50, 5±1μm; conductivity (10%, in water): 40μs / cm.

[0259] Talc: SiO2 content 57-63, MgO content 27-33, whiteness ≥95, particle size range: D50, 3±1μm; metal impurity content ≤0.025%.

[0260] Gel time test method:

[0261] (1) Crumble the resin of the prepreg into resin powder and place it on clean kraft paper.

[0262] (2) Collect the powder and place it through a 100-mesh sieve to sift out the fine powder, not less than 200 mg.

[0263] (3) Start the gel time tester and stabilize the temperature between the hot plates at 171±2℃.

[0264] (4) Clean the hot plate, use a small spoon to take 85~100 mg of powder and put it into the hot plate, and start the timer at the same time. When the gel system reaches 10 seconds, use a toothpick to stir it evenly. After a certain period of time, gently pull the sample. If the sample breaks, stop the timer. The timer reading at this time is the gel time.

[0265] Test method for resin fluidity:

[0266] (1) Cut four (4 ± 0.02) inch × (4 ± 0.02) inch square specimens on a square die punch. The specimens should be cut 3 mm away from the edge of the material.

[0267] (2) Use an electronic balance to weigh the total weight W1 of the four samples to an accuracy of 0.01g.

[0268] (3) Stack the four specimens neatly and sandwich them between two release films.

[0269] (4) The sandwich consisting of the sample, release film and steel plate is placed in a flow press to press the laminate.

[0270] (5) Pressing parameters are: temperature 171±5℃, pressure 0.45±0.03MPa, setting time 7min.

[0271] (6) Take out the pressed laminate and remove the release film.

[0272] (7) Use a round die punch to punch a disc with a diameter of 3.192 ± 0.02 inches in the center of the laminate.

[0273] (8) Use an electronic balance to weigh the disc, W2.

[0274] (9) Calculation: Fluidity (%) = [(W1-W2×2) / W1] × 100%.

[0275] Testing method for volatile matter content:

[0276] (1) On a square die punch, cut square specimens of (4 ± 0.02) inches × (4 ± 0.02) inches or (101.6 mm × 101.6 mm) (three pieces from the left, middle, and right sides of each specimen). Punch a small hole with a diameter of about 1 / 8 mm in the corner of the specimen. The specimen cannot be cut within 10 mm from the edge of the material.

[0277] (2) Weigh the sample to an accuracy of 0.001 g and record the weight W1.

[0278] (3) Use a paper clip to pass through the small hole of the sample and hang it under the shelf of the oven.

[0279] (4) Place the rack with the sample in an oven at 163±4℃ for 15±1min.

[0280] (5) Take the sample out of the oven and weigh it within 2 minutes to an accuracy of 0.001 g, and record the weight W2.

[0281] (6) Calculate the volatile matter content (%) = [(W1-W2) / W1] × 100%.

[0282] The detection method of comparative tracking index is: the highest voltage value that the material surface can withstand 50 drops of electrolyte without forming leakage traces.

[0283] The test method for thermal conductivity (thermal conductivity) is: ASTM D5470.

[0284] The test method for peel strength is: DIN 53273.

[0285] The method for detecting bow / warpage is to ensure that the four corners of the copper clad board are completely in contact with the plane. Then, measure the distance between the highest point in the middle and the plane. The calculation formula is: Warpage = (highest point distance / PCB board long side length) * 100%.

[0286] The testing method for glass transition temperature (Tg) is: E2 / 105 DSCIPC-TM-650 2.4.25.

[0287] The detection method of thermal decomposition temperature (Td) is: 10C / min, N, 5%WtLoss.

[0288] The test method for water absorption is:

[0289] (1) Cut a 2-inch x 2-inch sample and carefully smooth the edges on all four sides with 400-grit sandpaper to ensure a smooth surface.

[0290] (2) Etch off the copper foil on both sides, clean it and bake it in an oven at 105℃-110℃ for 1 hour to remove any residual substances and ensure it is dry;

[0291] (3) After cooling to room temperature, accurately weigh the sample in a clean, dry dish and record to an accuracy of 0.1 mg;

[0292] (4) Immerse the sample completely in distilled water at 23℃±1℃ for 24 hours;

[0293] (5) After taking out the moisture tester, wipe off any residual moisture on the surface immediately, and put it back on the precision balance to re-weigh it. Record the 0.1mg load value of the PCB sample in the final wet state;

[0294] (6) Calculate the water absorption rate of the PCB based on the initial weight and the weight in the wet state. Water absorption rate (%) = (weight in the wet state - initial weight) / initial weight × 100.

[0295] Example 1

[0296] The raw material formula of the adhesive solution for halogen-free and antimony-free flame retardant laminate (FR-4.1) is shown in Table 1.

[0297] Table 1 Raw material formula

[0298]

[0299] Note: Mixed solvent 1 refers to: DMF (N,N-dimethylformamide), ethanol, dimethyl sulfoxide (DMSO), and γ-butyrolactone (GBL) mixed in a mass ratio of 5:3:1:1;

[0300] The mixed solvent 2 is a mixture of PM (propylene glycol methyl ether), ethyl acetate and isopropanol in a mass ratio of 5:3:2.

[0301] The method for manufacturing the adhesive solution of the halogen-free and antimony-free flame-retardant laminate (FR-4.1) specifically comprises the following steps:

[0302] (1) Mix the mixed solvent 1 (added according to each component), the curing agent (added according to each component), the curing accelerator and the flame retardant, and stir until dissolved for 10-12 hours to obtain a mixture A;

[0303] (2) Mixing the mixture A with the coupling agent, the resin (added according to each component), and the mixed solvent 2 (added according to each component), and stirring for 1-2 hours to obtain a mixture B;

[0304] (3) Under stirring conditions, the mixture B and the inorganic filler (added according to each component) are mixed, and shear-ripened at a speed of 2200 rpm and a temperature of 50° C. for 5 hours, and then shear-ripened at a speed of 1100 rpm and a temperature of 50° C. for 7 hours (total aging time is about 12 hours), and finally a halogen-free and antimony-free flame-retardant laminate adhesive is obtained. Under the condition of a total aging time of about 10-12 hours, the gel time of the adhesive is 250-260 s.

[0305] When observing mixture A under a polarizing microscope at 40x (total magnification), there were less than 3 DICY crystals in any field of view.

[0306] Example 2

[0307] This embodiment provides a method for preparing a prepreg for a halogen-free and antimony-free flame-retardant laminate (FR-4.1), which comprises the following steps:

[0308] The electronic grade glass fiber cloth is coated with the adhesive solution described in Example 1, and then dried to obtain the product.

[0309] The electronic grade glass cloth (alkali-free glass fiber cloth for printed circuit boards) is a prepreg raw material conventionally used in the art, such as electronic grade glass cloth 7628 or electronic grade glass cloth 2116.

[0310] In the method for preparing the prepreg for the halogen-free and antimony-free flame-retardant laminate (FR-4.1), the coating equipment is a vertical glue coating machine.

[0311] (1) Prepreg produced from electronic grade glass cloth 7628:

[0312] The coating vehicle speed was 17 m / min.

[0313] The drying temperature is 210°C.

[0314] The temperature of the glue solution is 40°C.

[0315] The mass content of the resin in the prepreg can reach 45%.

[0316] The gel time of the prepreg can reach 90-100 s (the gel time of the glue solution can reach 250-260 s).

[0317] The fluidity of the prepreg can reach 20-28%.

[0318] The volatile matter of the prepreg is ≤0.5%.

[0319] (2) Prepreg produced from electronic grade glass cloth 2116:

[0320] The coating vehicle speed was 16 m / min.

[0321] The drying temperature is 215°C.

[0322] The temperature of the glue solution is 40°C.

[0323] The mass content of the resin in the prepreg is 55-56%.

[0324] The gel time of the prepreg can reach 85-95 s (the gel time of the glue solution can reach 250-260 s).

[0325] The fluidity of the prepreg can reach 26-32%.

[0326] The volatile matter of the prepreg is ≤0.5%.

[0327] Example 3

[0328] This embodiment provides a method for preparing a halogen-free and antimony-free flame-retardant laminate (FR-4.1), which comprises the following steps:

[0329] Lamination: 8 sheets of prepregs (1*2116+6*7628+1*2116) prepared in Example 2 are stacked and covered with copper foil on both the upper and lower surfaces to obtain a semi-finished plate. The semi-finished product is formed by 8 prepregs in the middle, upper and lower copper foils, upper and lower steel plates, and 18 pieces of kraft paper on the upper and lower surfaces;

[0330] ② The semi-finished product is subjected to hot-pressing and vacuum pressing to obtain.

[0331] No pressure is required when stacking. Stacking requires following four principles: the principle of matching high and low glue content, the principle of consistent layout, the principle of structural symmetry, and the principle of left and right matching.

[0332] In step ②, the pressing method is hot pressing and vacuum segmented pressing. Ensure that the plate is cooled gradually to avoid direct pressure release after hot pressing, which will cause large internal stress of the plate, and increase cold pressing to reduce plate warping.

[0333] The hot pressing vacuum value is 750 mmHg.

[0334] Stage 1: Start to evacuate until the hot pressing vacuum value reaches 750 mmHg, and maintain it at 740-750 mmHg. Hot pressing temperature: 120-210℃ (this temperature range indicates a linear increase from 120℃ to 210℃), hot pressing pressure: 5-25 kg / cm 2 (This pressure range represents from 5 kg / cm 2 Linear pressure increase to 25 kg / cm 2 ), hot pressing time: 55min. The heating and pressure increase are completed during the entire pressing process, that is, the pressure increase and heating time is 55min, the starting temperature of the hot pressing is 120℃, and the hot pressing pressure is 5 kg / cm 2 The hot pressing end point temperature is 210℃ and the hot pressing pressure is 25 kg / cm 2 That is, the heating rate of hot pressing is 1.63℃ / min, and the pressure increase rate of hot pressing is 0.36 kg / cm 2 / min.

[0335] Stage 2: Continuously evacuate to ensure that the hot pressing vacuum value is 740-750 mmHg, hot pressing temperature: 210℃, hot pressing pressure is divided into initial pressure, mid-term pressure and late pressure, among which: initial pressure is 25kg / cm 2 , hot pressing time is 10min, medium pressure is 35kg / cm 2 The hot pressing time is 35 minutes, and the later pressure is 20 kg / cm 2 , Hot pressing time: 15min.

[0336] Stage 3: Stop vacuuming, hot pressing temperature: 210-120℃ (this temperature range represents a linear temperature drop from 210℃ to 120℃), hot pressing pressure: 20-30 kg / cm 2 (This pressure range represents from 20 kg / cm 2 Linear pressure increase to 30 kg / cm 2), hot pressing time: 30min. Cooling and pressing are completed during the whole pressing process, that is, the time of pressing and cooling is 30min, the starting temperature of hot pressing is 210℃, and the hot pressing pressure is 20 kg / cm 2 The hot pressing end point temperature is 120℃ and the hot pressing pressure is 30 kg / cm 2 That is, the cooling rate of hot pressing is 3.00℃ / min, and the pressure increase rate of hot pressing is 0.33 kg / cm 2 / min.

[0337] Example 4

[0338] The raw material formula of the halogen-free and antimony-free flame-retardant laminate (CEM-3, among which the PP (semi-cured sheet) produced by electronic glass fiber felt requires this glue) is as follows.

[0339] Table 2

[0340]

[0341] Note: Mixed solvent A refers to: N,N-dimethylformamide DMF, ethanol, dimethyl sulfoxide DMSO, and γ-butyrolactone GBL mixed in a mass ratio of 5:3:1:1;

[0342] The mixed solvent B is obtained by mixing propylene glycol methyl ether PM, ethyl acetate EA and isopropanol in a mass ratio of 5:3:2.

[0343] The preparation method of the adhesive for halogen-free and antimony-free flame-retardant laminate (CEM-3, in which the PP (semi-cured sheet) produced by electronic glass fiber felt needs to use this adhesive) specifically includes the following steps:

[0344] (1) Mix the mixed solvent 1 (added according to each component), the curing agent (added according to each component), and the curing accelerator, and stir until dissolved for 10-12 hours to obtain a mixture A;

[0345] (2) Mixing the mixture A with the coupling agent, the resin (added according to each component), and the mixed solvent 2 (added according to each component), and stirring for 1-2 hours to obtain a mixture B;

[0346] (3) Under stirring conditions, the mixture B and the inorganic filler (added according to each component) are mixed, and shear-ripened at a speed of 1500 rpm and a glue temperature of 45° C. for 6 hours, and then shear-ripened at a speed of 1000 rpm and a glue temperature of 45° C. for 14 hours (total aging time is about 20 hours), and finally, the glue for halogen-free and antimony-free flame-retardant electronic glass fiber felt is obtained.

[0347] Example 5

[0348] The present embodiment provides a method for preparing a prepreg for a halogen-free and antimony-free flame-retardant laminate (CEM-3), which comprises the following steps:

[0349] The electronic glass fiber felt is coated with the glue in Example 4 and then dried to obtain the electronic glass fiber felt.

[0350] Among them, the electronic glass fiber felt is a product type purchased from Jiangsu Changhai Electronic Glass Fiber Felt: EMP-75A1 or EMP-105A1 (alkali metal content is not more than 0.8%), and its parameter indicators are shown in the following table.

[0351] Table 3

[0352]

[0353] Among them, the specific parameters of the prepreg produced from electronic grade glass fiber mat are:

[0354] The coating equipment is a horizontal glue coating machine, and the coating speed is 10m / min. The drying temperature is 220℃. The temperature of the glue solution is 35℃. The mass content of the resin in the prepreg can reach 85%. The fluidity of the prepreg can reach 25~30%. The volatile matter of the prepreg is ≤0.5%.

[0355] Example 6

[0356] This embodiment provides a method for preparing a halogen-free and antimony-free flame-retardant laminate (CEM-3), which comprises the following steps:

[0357] (1) Lamination: 4 prepregs (1*7628+2*EMP-105A1+1*7628) are stacked and covered with copper foil on both the upper and lower surfaces to obtain a semi-finished plate. The semi-finished product is formed by 4 prepregs in the middle, upper and lower copper foils, upper and lower steel plates, and 18 pieces of kraft paper on the upper and lower surfaces;

[0358] Among them, the 4 stacked prepregs are: 1 prepreg produced by electronic grade glass cloth 7628 + 2 prepregs produced by electronic grade glass fiber felt EMP-105A1 prepared in Example 5 + 1 prepreg produced by electronic grade glass cloth 7628.

[0359] Electronic grade glass cloth 7628 (purchased from Taishan Fiberglass, weight: 210g / m 2 ) The preparation method of the prepreg produced comprises the following steps:

[0360] Apply glue on electronic grade glass fiber cloth 7628 and then dry it. The coating equipment is a vertical glue machine, and the coating speed is 19m / min. The drying temperature is 210℃. The temperature of the glue is 40℃. The mass content of the resin in the prepreg can reach 50%. The gel time of the prepreg can reach 100-110s. The formula of the glue applied on the electronic grade glass fiber cloth 7628 is shown in the following table.

[0361] Table 4 Raw material formula

[0362]

[0363] Note: Mixed solvent 1 refers to: N,N-dimethylformamide DMF, ethanol, dimethyl sulfoxide DMSO, and γ-butyrolactone GBL mixed in a mass ratio of 5:3:1:1;

[0364] The mixed solvent 2 is obtained by mixing propylene glycol methyl ether PM, ethyl acetate EA and isopropanol in a mass ratio of 5:3:2.

[0365] The preparation method of coating glue on electronic grade glass fiber cloth 7628 specifically includes the following steps:

[0366] ① Mix the mixed solvent A (added according to each component), curing agent (added according to each component), curing accelerator and flame retardant, and stir until dissolved for 10-12 hours to obtain mixture A;

[0367] ② Mix mixture A with coupling agent, resin (added according to each component), and mixed solvent B (added according to each component), and stir for 1-2 hours to obtain mixture B;

[0368] ③ Under stirring conditions, mix mixture B and inorganic filler (added according to each component), first shear and mature at a speed of 2200rpm and a glue temperature of 50℃ for 5 hours, then shear and mature at a speed of 1100rpm and a glue temperature of 50℃ for 7 hours (total aging time is about 12 hours), and finally obtain the electronic grade glass fiber cloth 7628 coated with glue.

[0369] (2) The semi-finished product is subjected to hot pressing and vacuum pressing to obtain the product.

[0370] No pressure is required when stacking. Stacking requires the electronic glass fiber cloth PP to be on the outer layer and the electronic glass fiber felt to be in the core.

[0371] In step (2), the pressing method adopts hot pressing vacuum segmented pressing (the hot pressing vacuum value is 750 mmHg). Ensure that the plate is cooled gradually to avoid direct pressure release after hot pressing, which will cause large internal stress of the plate, and increase cold pressing to reduce plate warping.

[0372] Stage 1: Start to evacuate until the hot pressing vacuum value reaches 750 mmHg, and maintain it at 740-750 mmHg. Hot pressing temperature: 120-210℃ (this temperature range indicates a linear increase from 120℃ to 210℃), hot pressing pressure: 5-25 kg / cm 2 (This pressure range represents from 5 kg / cm 2 Linear pressure increase to 25 kg / cm 2 ), hot pressing time: 55min. The heating and pressure increase are completed during the entire pressing process, that is, the pressure increase and heating time is 55min, the starting temperature of the hot pressing is 120℃, and the hot pressing pressure is 5 kg / cm 2 The hot pressing end point temperature is 210℃ and the hot pressing pressure is 25 kg / cm 2 That is, the heating rate of hot pressing is 1.63℃ / min, and the pressure increase rate of hot pressing is 0.36 kg / cm 2 / min.

[0373] Stage 2: Continuously evacuate to ensure that the hot pressing vacuum value is 740-750 mmHg, hot pressing temperature: 210℃, hot pressing pressure is divided into initial pressure, mid-term pressure and late pressure, among which: initial pressure is 25kg / cm 2 , hot pressing time is 10min, medium pressure is 35kg / cm 2 The hot pressing time is 35 minutes, and the later pressure is 20 kg / cm 2 , Hot pressing time: 15min.

[0374] Stage 3: Stop vacuuming, hot pressing temperature: 210-120℃ (this temperature range represents a linear temperature drop from 210℃ to 120℃), hot pressing pressure: 20-30 kg / cm 2 (This pressure range represents from 20 kg / cm 2 Linear pressure increase to 30 kg / cm 2 ), hot pressing time: 30min. Cooling and pressing are completed during the whole pressing process, that is, the time of pressing and cooling is 30min, the starting temperature of hot pressing is 210℃, and the hot pressing pressure is 20 kg / cm 2 The hot pressing end point temperature is 120℃ and the hot pressing pressure is 30 kg / cm 2 That is, the cooling rate of hot pressing is 3.00℃ / min, and the pressure increase rate of hot pressing is 0.33 kg / cm 2 / min.

[0375] Example 7

[0376] (1) The formulation and manufacturing method of the adhesive for the halogen-free and antimony-free flame-retardant laminate (FR-4.1) are the same as those in Example 1.

[0377] (2) The preparation method of the prepreg for the halogen-free and antimony-free flame-retardant laminate (FR-4.1) is the same as that in Example 2.

[0378] (3) The preparation method of the halogen-free and antimony-free flame-retardant laminate (FR-4.1) in Example 7 is the same as that in Example 3 except that the hot pressing and vacuum segmented pressing process is different.

[0379] The hot pressing vacuum segmented pressing process is as follows:

[0380] Stage 1: Same as Example 3.

[0381] Stage 2: Continuously evacuate to ensure that the hot pressing vacuum value is 740-750 mmHg, hot pressing temperature: 210℃, hot pressing pressure is divided into initial pressure, mid-term pressure and late pressure, among which: initial pressure is 30kg / cm 2 , hot pressing time is 10min, medium pressure is 40kg / cm 2 , hot pressing time is 35min, and the later pressure is 25kg / cm 2 , Hot pressing time: 15min.

[0382] Stage 3: Same as Example 3.

[0383] Example 8

[0384] (1) The formulation and manufacturing method of the adhesive for the halogen-free and antimony-free flame-retardant laminate (FR-4.1) are the same as those in Example 1.

[0385] (2) The preparation method of the prepreg for the halogen-free and antimony-free flame-retardant laminate (FR-4.1) is the same as that in Example 2.

[0386] (3) The preparation method of the halogen-free and antimony-free flame-retardant laminate (FR-4.1) in Example 8 is the same as that in Example 3 except that the hot pressing and vacuum segmented pressing process is different.

[0387] The hot pressing vacuum segmented pressing process is as follows:

[0388] Stage 1: Same as Example 3.

[0389] Stage 2: Continuously evacuate to ensure that the hot pressing vacuum value is 740-750 mmHg, hot pressing temperature: 210℃, hot pressing pressure is divided into initial pressure, mid-term pressure and late pressure, among which: initial pressure is 25kg / cm 2 , hot pressing time is 15min, medium pressure is 35kg / cm 2The hot pressing time is 40 minutes, and the later pressure is 20 kg / cm 2 , Hot pressing time: 15min.

[0390] Stage 3: Same as Example 3.

[0391] Comparative Example 1

[0392] (1) The formulation and manufacturing method of the adhesive for the halogen-free and antimony-free flame-retardant laminate (FR-4.1) are the same as those in Example 1.

[0393] (2) The preparation method of the prepreg for the halogen-free and antimony-free flame-retardant laminate (FR-4.1) is the same as that in Example 2.

[0394] (3) The preparation method of the halogen-free and antimony-free flame-retardant laminate (FR-4.1) in Comparative Example 1 is the same as that in Example 3 except that the hot pressing and vacuum segmented pressing process is different.

[0395] The hot pressing vacuum segmented pressing process is as follows:

[0396] Stage 1: Hot pressing temperature: 60-200℃ (the temperature range means heating from 60℃ to 200℃), hot pressing pressure: 25 kg / cm 2 , hot pressing time: 55min.

[0397] Stage 2: Hot pressing temperature: 200°C, hot pressing pressure: 35kg / cm 2 , hot pressing time: 65min.

[0398] Stage 3: Hot pressing temperature: 200-60℃ (the temperature range represents a linear decrease from 200℃ to 60℃), hot pressing pressure: 30 kg / cm 2 , hot pressing time: 20-40min.

[0399] Comparative Example 2

[0400] (1) The formulation and manufacturing method of the adhesive for the halogen-free and antimony-free flame-retardant laminate (FR-4.1) are the same as those in Example 1.

[0401] (2) The preparation method of the prepreg for the halogen-free and antimony-free flame-retardant laminate (FR-4.1) is the same as that in Example 2.

[0402] (3) The preparation method of the halogen-free and antimony-free flame-retardant laminate (FR-4.1) in Comparative Example 2 is the same as that in Example 3 except that the hot pressing and vacuum segmented pressing process is different.

[0403] The hot pressing vacuum segmented pressing process is as follows:

[0404] Stage 1: Same as Example 3.

[0405] Stage 2: Continuously evacuate to ensure that the hot pressing vacuum value is 740-750 mmHg, hot pressing temperature: 210℃, hot pressing pressure is divided into initial pressure, mid-term pressure and late pressure, among which: initial pressure is 15kg / cm 2 , hot pressing time is 10min, medium pressure is 25kg / cm 2 , hot pressing time is 35min, and the later pressure is 10kg / cm 2 , Hot pressing time: 15min.

[0406] Stage 3: Same as Example 3.

[0407] Comparative Example 3

[0408] (1) The formulation and manufacturing method of the adhesive for the halogen-free and antimony-free flame-retardant laminate (FR-4.1) are the same as those in Example 1.

[0409] (2) The preparation method of the prepreg for the halogen-free and antimony-free flame-retardant laminate (FR-4.1) is the same as that in Example 2.

[0410] (3) The preparation method of the halogen-free and antimony-free flame-retardant laminate (FR-4.1) in Comparative Example 3 is the same as that in Example 3 except that the hot pressing and vacuum segmented pressing process is different.

[0411] The hot pressing vacuum segmented pressing process is as follows:

[0412] Stage 1: Same as Example 3.

[0413] Stage 2: Continuously evacuate to ensure that the hot pressing vacuum value is 740-750 mmHg, hot pressing temperature: 210℃, hot pressing pressure is divided into initial pressure, mid-term pressure and late pressure, among which: initial pressure is 20kg / cm 2 , hot pressing time is 10min, medium pressure is 30kg / cm 2 , hot pressing time is 35min, and the later pressure is 15kg / cm 2 , Hot pressing time: 15min.

[0414] Stage 3: Same as Example 3.

[0415] Comparative Example 4

[0416] (1) The formulation and manufacturing method of the adhesive for the halogen-free and antimony-free flame-retardant laminate (FR-4.1) are the same as those in Example 1.

[0417] (2) The preparation method of the prepreg for the halogen-free and antimony-free flame-retardant laminate (FR-4.1) is the same as that in Example 2.

[0418] (3) The preparation method of the halogen-free and antimony-free flame-retardant laminate (FR-4.1) in Comparative Example 3 is the same as that in Example 3 except that the hot pressing and vacuum segmented pressing process is different.

[0419] The hot pressing vacuum segmented pressing process is as follows:

[0420] Stage 1: Same as Example 3.

[0421] Stage 2: Continuously evacuate to ensure that the hot pressing vacuum value is 740-750 mmHg, hot pressing temperature: 210℃, hot pressing pressure is divided into initial pressure, mid-term pressure and late pressure, among which: initial pressure is 35kg / cm 2 , hot pressing time is 10min, medium pressure is 45kg / cm 2 , hot pressing time is 35min, and the later pressure is 30kg / cm 2 , Hot pressing time: 15min.

[0422] Stage 3: Same as Example 3.

[0423] Effect Example 1

[0424] The copper clad laminates obtained in Example 3, Example 6, Example 7, Example 8, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 were subjected to performance measurements, and the results are shown in Tables 5 and 6.

[0425] Table 5 Performance parameters of copper clad laminate

[0426]

[0427] Table 6 Performance parameters of copper clad laminate

[0428]

[0429] According to Table 5 and Table 6, we can know that:

[0430] (1) The hot pressing process of the present invention has a wide range of applications. The FR-4.1 in Examples 3 and 7-8 and the CEM-3 in Example 6 can be made into sheets with excellent comprehensive performance by using the hot pressing process of the present invention.

[0431] (2) The temperature and pressure of the hot pressing process in the present invention have a great influence on the performance of the laminate.

[0432] As shown in Comparative Example 1, when stage 2 in the hot pressing vacuum staged pressing process does not adopt staged pressing, the board texture is leaking, the leakage tracking index is lower, the peel strength is reduced, the warpage is higher, the thermal stress is worse, the flame retardant level is reduced, the glass transition temperature is reduced, and the water absorption rate is increased. The overall performance of the copper clad laminate is significantly worse than that of Examples 3, 6, and 7-8.

[0433] As shown in Comparative Examples 2-4, when the initial pressure, mid-term pressure and late pressure in stage two of the hot pressing vacuum staged pressing process are not within the range, the board texture shows leakage or copper wrinkles, the thickness uniformity deteriorates, the tracking index decreases, the warpage increases, the thermal stress deteriorates, the water absorption rate increases, and the overall performance of the copper clad laminate is significantly worse than that of Examples 3, 6, 7-8.

Claims

1. A method for preparing a laminate, characterized in that: It includes the following steps: (1) applying a glue solution to a reinforcing material and drying the solution to obtain a prepreg; the raw materials of the glue solution include a resin, a curing agent, a curing accelerator, a coupling agent and a solvent, and optionally, the raw materials also include an inorganic filler; (2) stacking two or more prepregs and hot pressing them to obtain the laminate; The hot pressing process includes stage one, stage two, and stage three in sequence, wherein: In the first stage, the vacuum value is 740-760 mmHg, the temperature at the start of hot pressing is 110-130°C, and the pressure at the start of hot pressing is 5-10 kg / cm 2 The temperature at the end of hot pressing is 200-220℃, and the pressure at the end of hot pressing is 25-30kg / cm 2 , the hot pressing time is 50-60min; In the second stage, the vacuum value is 740-760 mmHg, the temperature of hot pressing is 200-220°C, and the pressure of hot pressing is divided into initial pressure, intermediate pressure and late pressure; the initial pressure is 25-30 kg / cm 2 The initial pressure pressing time is 10-15 min; the intermediate pressure is 35-40 kg / cm 2 The mid-term pressure pressing time is 35-40 min; the late pressure is 20-25 kg / cm 2 The time of the late pressure pressing is 10-15 min; The third stage: vacuum or non-vacuum conditions, the temperature at the start of hot pressing is 200-220°C, and the pressure at the start of hot pressing is 20-25 kg / cm 2 The temperature at the end of hot pressing is 110-130℃, and the pressure at the end of hot pressing is 30-35kg / cm 2 The hot pressing time is 20-40min.

2. The method for preparing a laminate according to claim 1, characterized in that: The first stage meets one or more of the following conditions: (1) In the first stage, the vacuum value is 740-750 mmHg; (2) In the first stage, the temperature at the starting point of the hot pressing is 120° C. (3) In the first stage, the pressure at the start of the hot pressing is 5 kg / cm 2 or 10kg / cm 2 ; (4) In the first stage, the temperature at the end of the hot pressing is 210° C. (5) In the first stage, the pressure at the end of the hot pressing is 25 kg / cm 2 or 30 kg / cm 2 ; (6) In the first stage, the hot pressing time is 55 min; (7) In the first stage, the temperature of the hot pressing increases linearly or nonlinearly; For example, in the first stage, the temperature of the hot pressing is linearly increased from 110-130°C to 200-220°C within a time range of 50-60min; in the first stage, the heating rate of the hot pressing can be 1.00-2.00°C / min, for example, 1.63°C / min; and (8) in said stage 1, the pressure of hot pressing increases linearly or nonlinearly; For example, in the first stage, the pressure of the hot pressing is within the range of 50-60 min, from 4-6 kg / cm 2 Increase linearly to 25-30 kg / cm 2 In the first stage, the pressure increase rate of hot pressing can be 0.10-0.50 kg / cm 2 / min, for example 0.36 kg / cm 2 / min.

3. The method for preparing a laminate according to claim 1, characterized in that: The second stage meets one or more of the following conditions: (1) In the second stage, the vacuum value is 740-750 mmHg; (2) In the second stage, the temperature of hot pressing is 210°C; (3) In the second stage, the initial pressure is 25 kg / cm 2 or 30 kg / cm 2 ; (4) In the second stage, the initial pressure pressing time is 10 minutes or 15 minutes; (5) In the second stage, the intermediate pressure is 35 kg / cm 2 or 40 kg / cm 2 ; (6) In the second stage, the duration of the intermediate pressure suppression is 35 minutes or 40 minutes; (7) In the second stage, the later pressure is 20 kg / cm 2 or 25 kg / cm 2 ; In the second stage of (8), the time of the later pressure pressing is 15 minutes.

4. The method for preparing a laminate according to claim 1, wherein: The third stage meets one or more of the following conditions: (1) In the third stage, hot pressing is performed under the condition of stopping vacuuming; (2) In the third stage, the temperature at the starting point of the hot pressing is 210° C. (3) In the third stage, the pressure at the start of the hot pressing is 20 kg / cm 2 ; (4) In the third stage, the temperature at the end of the hot pressing is 1200° C. (5) In the third stage, the pressure at the end of the hot pressing is 30 kg / cm 2 ; (6) In the third stage, the hot pressing time is 30 min; (7) In the third stage, the temperature of the hot pressing is reduced linearly or nonlinearly; For example, in the third stage, the temperature of the hot pressing is reduced from 200-220°C to 110-130°C within a time range of 20-40 minutes; in the third stage, the cooling rate of the hot pressing can be 2.00-4.00°C / min, for example, 3.00°C / min; (8) In the third stage, the pressure of the hot pressing increases linearly or nonlinearly; For example, in the third stage, the pressure of the hot pressing is within the range of 20-40 min, from 20-25 kg / cm 2 Increase to 30-35 kg / cm 2 In the third stage, the pressure increase rate of hot pressing can be 0.10-0.50 kg / cm 2 / min, for example 0.33 kg / cm 2 / min.

5. The method for preparing a laminate according to any one of claims 1 to 4, characterized in that: The solvent includes mixed solvent 1 and mixed solvent 2; The mixed solvent 1 includes N,N-dimethylformamide, ethanol, dimethyl sulfoxide, and γ-butyrolactone. The mass ratio of the N,N-dimethylformamide, the ethanol, the dimethyl sulfoxide, and the γ-butyrolactone can be (4-6): (2-4): 1:1, for example, 5:3:1:1; The mixed solvent 2 comprises propylene glycol methyl ether, ethyl acetate and isopropanol. The mass ratio of the propylene glycol methyl ether, the ethyl acetate and the isopropanol can be (4-6):(2-4):2, for example, 5:3:

2.

6. The method for preparing a laminate according to claim 5, characterized in that: The raw materials of the glue solution include the following component A: (1) 360-440 parts of bisphenol A epoxy resin, wherein the bisphenol A epoxy resin has an epoxy equivalent of 185-190 g / eq and a viscosity of 12000-15000 mPa·s at 25° C.; 1260-1540 parts of a DOPO type modified phosphorus-containing epoxy resin, wherein the DOPO type modified phosphorus-containing epoxy resin has an epoxy equivalent of 295-335 g / eq; 180-220 parts of bisphenol A novolac epoxy resin, wherein the epoxy equivalent of the bisphenol A novolac epoxy resin is 190-220 g / eq; 90-110 parts of a novolac epoxy resin, wherein the novolac epoxy resin has an epoxy equivalent of 176-181 g / eq; 270-330 parts of bisphenol A type phosphorus-containing phenolic resin, wherein the viscosity of the bisphenol A type phosphorus-containing phenolic resin at 25° C. is 500-2500 mPa.s; 90-110 parts of a tetrafunctional novolac epoxy resin, wherein the epoxy equivalent of the tetrafunctional novolac epoxy resin is 200-220 g / eq; 450-550 parts of the mixed solvent 1, 135-165 parts of the mixed solvent 2; 0.5-1.5 parts of a curing accelerator; 18-22 parts of silane coupling agent; Optionally, the raw material further comprises an inorganic filler.

7. The method for preparing a laminate according to claim 5, characterized in that: The raw materials of the glue solution include the following component B: 540-660 parts of bisphenol A epoxy resin, wherein the bisphenol A epoxy resin has an epoxy equivalent of 185-190 g / eq and a viscosity of 12000-15000 mPa·s at 25° C.; 900-1100 parts of DOPO type modified phosphorus-containing epoxy resin, wherein the epoxy equivalent of the DOPO type modified phosphorus-containing epoxy resin is 295-335 g / eq; 360-440 parts of solid bisphenol A epoxy resin, wherein the solid bisphenol A epoxy resin has an epoxy equivalent of 840-900 g / eq and a melt viscosity of 6000-9000 mPa·s at 150° C.; 180-220 parts of MDI modified epoxy resin, wherein the epoxy equivalent of the MDI modified epoxy resin is 250-310 g / eq; and, 450-550 parts of a linear bisphenol A formaldehyde resin, wherein the linear bisphenol A formaldehyde resin has a hydroxyl equivalent of 120-124 g / eq; 450-550 parts of the mixed solvent 1, 765-935 parts of the mixed solvent 2; 72-88 parts of curing agent; 0.9-1.1 parts of curing accelerator; 18-22 parts of a silane coupling agent; and, Inorganic filler.

8. The method for preparing a laminate according to claim 6 or 7, characterized in that the method for preparing the adhesive solution comprises the following steps: (1) mixing the mixed solvent 1, the curing agent, the curing accelerator and a portion of the inorganic filler, and stirring until dissolved to obtain a mixture A; (2) mixing the mixture A with the silane coupling agent, the resin, and the mixed solvent 2, and stirring to obtain a mixture B; (3) Under stirring conditions, the mixture B and the remaining inorganic filler are mixed, sheared and ripened to obtain the glue solution.

9. The method for preparing a laminate according to any one of claims 1 to 4, characterized in that one side or both sides of the prepreg are also covered with a metal foil or a release film.

10. A laminated board, characterized in that: The laminate is prepared by the method for preparing the laminate as described in any one of claims 1 to 9.

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