CN112694623B

CN112694623B - Resin glue solution, prepreg and metal foil-clad laminate

Info

Publication number: CN112694623B
Application number: CN202011578017.7A
Authority: CN
Inventors: 刘文龙; 黄海林; 钟健伟; 余林元; 黄晨光; 葛洪君
Original assignee: Shengyi Technology Co Ltd
Current assignee: Shengyi Technology Co Ltd
Priority date: 2020-12-28
Filing date: 2020-12-28
Publication date: 2023-04-07
Anticipated expiration: 2040-12-28
Also published as: CN112694623A

Abstract

The invention provides a resin glue solution, a prepreg and a metal foil-clad laminate, wherein the resin glue solution comprises a resin composition and a solvent; the resin composition comprises the following components in parts by weight: 80 to 120 portions of epoxy resin, 0.5 to 5 portions of dicyandiamide and 0.001 to 2 portions of curing accelerator; the solvent comprises a mixture of a polyol ether solvent and dimethyl sulfoxide. In the resin glue solution, a dicyandiamide-cured epoxy resin system is matched with a specific mixed solvent to form a uniform and stable glue solution, dicyandiamide precipitation in subsequent processing is avoided, the problems of nitrogen oxides in incinerator exhaust tail gas and DMF (dimethyl formamide) residue in a laminated board in the preparation process of the metal-clad laminated board are effectively solved, the processability of the resin glue solution is improved, the metal-clad laminated board prepared by the resin glue solution has higher glass transition temperature, heat resistance, peeling strength and reliability, and the application requirement of a high-performance printed circuit board is fully met.

Description

Resin glue solution, prepreg and metal foil-clad laminated board

Technical Field

The invention belongs to the technical field of printed circuit boards, and particularly relates to a resin glue solution, a prepreg and a metal foil-clad laminated board.

Background

In recent years, electronic products are gradually developing towards miniaturization, multifunctionality and high performance, and electronic components have a tendency of high integration in order to match with the development direction of the electronic products. Therefore, printed Circuit Boards (PCBs) are required to have high heat resistance and reliability under high-density packaging conditions as substrate materials in electronic devices and electronic components.

Metal-clad laminates are the primary materials for making PCBs, and typically include a reinforcing material having a reinforcing effect and a resin composition, and the performance of the metal-clad laminate depends largely on the choice of the resin composition. The resin composition which is most widely applied in the metal foil-clad laminate at present is an epoxy resin system, and a cured product of the epoxy resin composition which takes an epoxy resin and a curing agent as essential components shows good heat resistance and insulation, and has outstanding processability and cost advantages.

Dicyandiamide (DICY) is used as a curing agent for epoxy resin, and a cured product obtained by curing the epoxy resin has good insulating properties, and is widely used in a laminate, a metal foil-clad laminate, and a PCB. For example, CN105482753A discloses a high CTI resin composition comprising, in parts by weight of solids: 80 to 125 parts of brominated epoxy resin, 2.0 to 3.0 parts of dicyandiamide, 0.05 to 0.15 part of curing accelerator and 70 to 100 parts of filler composition. The resin composition has good thermal conductivity and high comparative tracking index CTI, when the resin composition is used as a raw material for preparing a metal foil-clad laminated plate, solid components are required to be mixed with organic solvents of dimethylformamide and acetone to prepare thermosetting epoxy resin glue, then a reinforcing material is impregnated in the resin glue to prepare a prepreg, and the prepreg and a metal foil are laminated to obtain the metal foil-clad laminated plate.

The organic solvent is an indispensable component in the production process of the wet metal foil-clad laminate, does not participate in chemical reaction basically, and is mainly used for dissolving solid raw materials (such as resin, curing agent, curing accelerator and the like) and adjusting the solid content of resin glue solution so as to improve the processing performance and facilitate the gluing of the glue solution. In an epoxy resin system using dicyandiamide as a curing agent, dimethylformamide (DMF) is required to be used as a solvent because dicyandiamide has very limited solubility in a common organic solvent. However, the content of nitrogen element in DMF is high, and a large amount of nitrogen oxide can be generated after volatile matters generated by drying corresponding prepreg are cracked by high-temperature combustion of an incinerator, thereby causing environmental pollution.

In addition, in the dicyandiamide cured epoxy system using DMF as a solvent, DMF inevitably remains in the PCB or the metal foil-clad laminate. At present, DMF is classified as an environmental "high concern substance" in many countries and regions, for example, the content of the environmental "high concern substance" in electronic products in European Union is required to be less than 1000ppm, and some end manufacturers require that the residual amount of DMF in PCB substrate materials is less than 600ppm, so that the residual amount of DMF in metal clad laminates is also required to be less than 600ppm. However, the existing dicyandiamide curing epoxy system product is difficult to meet the requirements.

Therefore, it is an urgent problem in the art to develop a resin material and a metal-clad laminate that have both excellent heat resistance and reliability and meet the environmental requirements.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a resin adhesive solution, a prepreg and a metal-clad laminate, wherein a resin composition in the resin adhesive solution comprises a dicyandiamide-cured epoxy resin system, and a specific mixed solvent is matched and used, so that the problems of nitrogen oxide in incinerator-discharged tail gas and DMF (dimethyl formamide) residue in the laminate in the preparation process of the metal-clad laminate are effectively solved, the processability of the resin adhesive solution is improved, and the metal-clad laminate prepared by the resin adhesive solution has higher glass transition temperature, heat resistance and peeling strength.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a resin glue solution, comprising a resin composition and a solvent; the resin composition comprises the following components in parts by weight: 80 to 120 portions of epoxy resin, 0.5 to 5 portions of dicyandiamide and 0.001 to 2 portions of curing accelerator; the solvent comprises a mixture of a polyol ether solvent and dimethyl sulfoxide.

In the resin glue solution provided by the invention, the resin composition is an epoxy resin system containing a dicyandiamide curing agent, and the solvent comprises a polyol ether solvent and dimethyl sulfoxide (DMSO). The mixed solvent does not contain nitrogen elements, effectively solves the problems of nitrogen oxides in the exhaust gas of the incinerator and the residue of environment 'high concern substances' in the laminated board, and meets the requirement of environmental protection; meanwhile, the dicyandiamide and the water are mutually cooperated, so that on one hand, dicyandiamide can be fully dissolved to form uniform and stable resin glue solution, and the problem of dicyandiamide precipitation or phase splitting cannot occur in the using process; on the other hand, the combination of the polyol ether solvent and DMSO gives a cured product of the resin composition a high glass transition temperature, heat resistance, and adhesion to a metal foil; further, the polyalcohol ether solvent and the DMSO are compounded synergistically, so that the produced prepreg has good appearance, and the performance defect of the metal foil-clad laminated board cannot be caused. According to the invention, through the screening of the solvent and the matching of the solvent and the resin composition, the resin glue solution is uniform and stable, the processability of the resin glue solution is improved, the metal-clad laminate prepared from the resin glue solution has higher glass transition temperature, heat resistance, peeling strength and reliability, and the problems of nitrogen oxides in the exhaust gas of an incinerator and DMF (dimethyl formamide) residue in the laminate in the preparation process of the metal-clad laminate are solved.

The epoxy resin in the resin composition is 80 to 120 parts, for example, 82 parts, 85 parts, 88 parts, 90 parts, 92 parts, 95 parts, 98 parts, 100 parts, 102 parts, 105 parts, 108 parts, 110 parts, 112 parts, 115 parts or 118 parts, and specific values therebetween are not exhaustive, and the invention is not limited to the specific values included in the range for brevity and conciseness.

The dicyandiamide is 0.5 to 5 parts, for example, it may be 0.8 part, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, 3.2 parts, 3.5 parts, 3.8 parts, 4 parts, 4.2 parts, 4.5 parts or 4.8 parts, and specific point values between the above point values are limited to space and simplicity, and the invention is not exhaustive list of the specific point values included in the range.

The curing accelerator is 0.001 to 2 parts, and for example, may be 0.003, 0.005, 0.008, 0.01, 0.03, 0.05, 0.07, 0.09, 0.1, 0.3, 0.5, 0.7, 0.9, 1, 1.2, 1.5 or 1.8 parts, and specific points between the above points are not limited to space and the invention is not exhaustive, and the specific points included in the range are not limited to space.

Preferably, the solids content of the resin dope is 40-85%, such as 42%, 45%, 48%, 50%, 52%, 55%, 58%, 60%, 62%, 65%, 68%, 70%, 72%, 75%, 78%, 80%, 82% or 84%, and specific values therebetween, not to be limited by space and for the sake of brevity, the present invention is not exhaustive of the specific values included in the ranges. If the solid content of the resin glue solution is less than 40%, the speed of the gluing machine needs to be reduced to fully dry the solvent, so that the production efficiency is reduced; if the solid content of the resin glue solution is more than 85 percent, the uniformity of the resin glue solution is influenced, and the dispersion of the resin and the filler is not facilitated.

Preferably, the epoxy resin includes any one of or a combination of at least two of bisphenol a type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, novolac epoxy resin, biphenyl type epoxy resin, or dicyclopentadiene type epoxy resin.

Preferably, the epoxy equivalent of the epoxy resin is 120 to 520g/eq, for example 130g/eq, 140g/eq, 150g/eq, 160g/eq, 170g/eq, 180g/eq, 190g/eq, 200g/eq, 220g/eq, 250g/eq, 280g/eq, 300g/eq, 320g/eq, 350g/eq, 380g/eq, 400g/eq, 420g/eq, 450g/eq, 480g/eq, 500g/eq or 510g/eq, and the specific point values between the above point values are limited in breadth and for the sake of brevity, and the present invention does not exhaust the specific point values included in the range.

Preferably, the curing accelerator includes any one of imidazole curing accelerator, organophosphine curing accelerator, organoamine curing accelerator, peroxide or organic metal salt or a combination of at least two thereof.

Preferably, the imidazole-based curing accelerator comprises any one of 2-methylimidazole, 2-methyl-4-ethylimidazole, 2-phenylimidazole or 2-undecylimidazole or a combination of at least two of the two.

Preferably, the organophosphine-based curing accelerator includes any one of tributylphosphine, triphenylphosphine, or tripropylphosphine, or a combination of at least two thereof.

Preferably, the organic amine-based curing accelerator is a tertiary amine compound, and more preferably is benzyldimethylamine.

Preferably, the peroxide comprises any one of dicumyl peroxide, 2, 5-dimethyl-2, 5-bis (t-butylperoxy) hexyne-3, 2, 5-dimethyl-2, 5-bis (t-butylperoxy) hexane, or α, α' -bis (t-butylperoxy) dicumyl benzene, or a combination of at least two thereof.

Preferably, the organometallic salt comprises any one of zinc naphthenate, cobalt naphthenate, tin octoate or cobalt octoate or a combination of at least two thereof.

Preferably, the content of the polyol ether-based solvent in the solvent is 50 to 90% by mass, for example, 52%, 55%, 58%, 60%, 62%, 65%, 68%, 70%, 72%, 75%, 78%, 80%, 82%, 85% or 88% by mass, and specific values therebetween are not exhaustive, and for brevity and conciseness, the invention is not limited to specific values included in the range.

Preferably, the polyhydric alcohol ether solvent includes any one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, or propylene glycol dimethyl ether, or a combination of at least two thereof.

Preferably, the content of dimethyl sulfoxide in the solvent is 10 to 50% by mass, for example, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45% or 48% by mass, and specific values therebetween are not exhaustive, but for reasons of brevity and conciseness.

As a preferable technical scheme of the invention, the solvent comprises 50-90% of polyalcohol ether solvent and 10-50% of dimethyl sulfoxide by mass percentage, and the polyalcohol ether solvent and the dimethyl sulfoxide are cooperated with each other by a specific proportion, so that on one hand, the solvent has excellent solubility, on the other hand, the processability of the resin glue solution can be improved, the glass transition temperature, the heat resistance and the reliability of a cured resin glue solution and the adhesive force with the metal foil can be improved, and the metal foil-clad laminated plate prepared by the solvent has good heat resistance, peeling strength and reliability. If the mass percentage of the dimethyl sulfoxide in the solvent is less than 10 percent, the effect of assisting in dissolving dicyandiamide cannot be effectively realized, and in order to ensure that dicyandiamide is fully dissolved, a large amount of polyol ether solvents are correspondingly used, so that the solid content of the resin glue solution is sharply reduced, and the production efficiency is reduced or the production energy consumption is increased when the prepreg is produced; if the content of dimethyl sulfoxide is too high, the residue of volatile matters in the produced prepreg is high, and the heat resistance of a metal foil laminate produced by the corresponding prepreg is reduced.

Preferably, dimethylformamide is also included in the solvent.

The content of dimethylformamide in the solvent is preferably 10% by mass or less, and may be, for example, 9.5%, 9%, 8.5%, 8%, 7.5%, 7%, 6.5%, 6%, 5.5%, 5%, 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, or 0.5%, and more preferably 5% by mass or less.

In the resin glue solution provided by the invention, the resin composition can also comprise any one or a combination of at least two of a filler, a flame retardant, other curing agents or a silane coupling agent.

Preferably, the resin composition further comprises 20 to 200 parts by weight of a filler, for example, the filler may be 25 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts, 110 parts, 120 parts, 130 parts, 140 parts, 150 parts, 160 parts, 170 parts, 180 parts, 190 parts, or the like.

The kind of the filler is not particularly limited, and exemplary includes but is not limited to: any one or a combination of at least two of silica, aluminum hydroxide, magnesium hydroxide, boehmite, molybdenum oxide, zinc molybdate, titanium dioxide, zinc oxide, boron nitride, aluminum nitride, silicon carbide, alumina, barium sulfate, glass frit, or short glass fibers.

In a second aspect, the present invention provides a method for preparing a resin glue solution according to the first aspect, the method comprising the following steps:

(1) Uniformly mixing dicyandiamide and a solvent to obtain a dicyandiamide pre-solution;

(2) And (2) mixing the dicyandiamide pre-solution obtained in the step (1), epoxy resin and a curing accelerator, and uniformly dispersing to obtain the resin glue solution.

Preferably, the dicyandiamide content in the dicyandiamide pre-solution in the step (1) is 7 to 12% by mass, for example, 7.2%, 7.5%, 7.8%, 8%, 8.2%, 8.5%, 8.8%, 9%, 9.2%, 9.5%, 9.8%, 10%, 10.2%, 10.5%, 10.8%, 11%, 11.2%, 11.5% or 11.8%, and specific points between the above points are limited by space and for simplicity, and the invention is not exhaustive.

Preferably, the mixing method in step (2) is: and pumping the dicyandiamide pre-solution into epoxy resin, adding a curing accelerator, and uniformly dispersing to obtain the resin glue solution.

In a third aspect, the present invention provides a prepreg comprising a reinforcing material, and a resin composition adhered to the reinforcing material; the resin composition is obtained by impregnating the resin cement as described in the first aspect and drying.

Preferably, the reinforcing material comprises any one of glass fiber cloth, organic fiber cloth, glass fiber paper or organic fiber paper, and is further preferably glass fiber cloth.

Preferably, the glass fiber cloth comprises E-glass fiber cloth, D-glass fiber cloth, L-glass fiber cloth, M-glass fiber cloth, S-glass fiber cloth, T-glass fiber cloth or NE-glass fiber cloth.

Preferably, the organic fiber cloth comprises polyimide fiber cloth, polyamide fiber cloth, polyester fiber cloth, polyphenylene ether fiber cloth or liquid crystal polymer fiber cloth.

The prepreg provided by the invention is prepared by adopting the following method, and the method comprises the following steps: and (3) impregnating a reinforcing material with the resin glue solution, and then drying to obtain the prepreg.

Preferably, the drying temperature is 100-200 ℃, such as 105 ℃, 110 ℃, 115 ℃, 120 ℃, 125 ℃, 130 ℃, 135 ℃, 140 ℃, 145 ℃, 150 ℃,155 ℃, 160 ℃, 165 ℃, 170 ℃, 175 ℃, 180 ℃, 185 ℃,190 ℃ or 195 ℃.

Preferably, the drying time is 1 to 10min, such as 2min, 3min, 4min, 5min, 6min, 7min, 8min or 9min and the like.

As another preferred technical solution of the present invention, the prepreg is prepared by a method comprising: impregnating a reinforcing material in the resin glue solution to obtain the reinforcing material impregnated with the resin glue solution; and processing the reinforcing material soaked in the resin glue solution by a gluing machine to obtain the prepreg.

Preferably, the gluing machine is a vertical gluing machine, and the prepreg is prepared by controlling the conditions of the rotating speed of the metering shaft, the vehicle speed, the wind temperature, the oil temperature and the like.

Preferably, the rotation speed of the metering shaft of the vertical gluing machine is 1.7-1.9 m/min, and can be 1.72m/min, 1.74m/min, 1.76m/min, 1.78m/min, 1.8m/min, 1.82m/min, 1.84m/min, 1.85m/min, 1.87m/min or 1.89m/min, etc.

Preferably, the speed of the vertical gluing machine is 8-12 m/min, such as 8.2m/min, 8.5m/min, 8.8m/min, 9m/min, 9.2m/min, 9.5m/min, 9.8m/min, 10m/min, 10.2m/min, 10.5m/min, 10.8m/min, 11m/min, 11.2m/min, 11.5m/min, or 11.8 m/min.

Preferably, the air temperature of the vertical sizing machine is 140 to 160 ℃, and for example, 141 ℃, 143 ℃, 145 ℃, 147 ℃, 149 ℃, 150 ℃, 151 ℃, 153 ℃,155 ℃, 157 ℃ or 159 ℃ can be set.

The oil temperature of the vertical gluing machine is preferably 170 to 190 ℃, and may be 171 ℃, 173 ℃, 175 ℃, 177 ℃, 179 ℃, 180 ℃, 181 ℃, 183 ℃, 185 ℃, 187 ℃, 189 ℃ or the like, for example.

In a fourth aspect, the present invention provides a laminate comprising at least one prepreg according to the third aspect.

In a fifth aspect, the present invention provides a metal-clad laminate comprising at least one prepreg according to the third aspect, and a metal foil provided on one or both sides of the prepreg.

Preferably, the metal foil-clad laminate includes at least 1 prepreg, and the number of the prepregs may be adjusted as needed, and may be 1 to 40, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, or 38.

The metal foil may be copper foil, aluminum foil, silver foil, nickel foil, alloy foil, or the like, and preferably, the metal foil is copper foil.

The metal-clad laminate provided by the present invention can be produced by a method comprising: overlapping metal foils on one side or two sides of 1 prepreg, and curing to obtain the metal foil-clad laminated board; or, at least 2 sheets of prepregs are laminated to form a laminate, and then a metal foil is laminated on one side or both sides of the laminate and cured to obtain the metal foil-clad laminate.

Preferably, the curing is performed in a vacuum thermocompressor.

Preferably, the curing temperature is 130-230 ℃, such as 135 ℃, 140 ℃, 145 ℃, 150 ℃,155 ℃, 160 ℃, 165 ℃, 170 ℃, 175 ℃, 180 ℃, 185 ℃,190 ℃, 195 ℃, 200 ℃, 205 ℃, 210 ℃, 215 ℃,220 ℃ or 225 ℃.

Preferably, the curing pressure is 10 to 50kgf/cm ² For example, 12kgf/cm ² 、15kgf/cm ² 、18kgf/cm ² 、20kgf/cm ² 、22kgf/cm ² 、25kgf/cm ² 、28kgf/cm ² 、30kgf/cm ² 、32kgf/cm ² 、35kgf/cm ² 、38kgf/cm ² 、40kgf/cm ² 、42kgf/cm ² 、45kgf/cm ² Or 48kgf/cm ² And so on.

Preferably, the degree of vacuum of the curing is 10 to 900mm Hg, and may be, for example, 20mm Hg, 30mm Hg, 50mm Hg, 70mm Hg, 90mm Hg, 100mm Hg, 150mm Hg, 200mm Hg, 250mm Hg, 300mm Hg, 350mm Hg, 400mm Hg, 450mm Hg, 500mm Hg, 550mm Hg, 600mm Hg, 650mm Hg, 700mm Hg, 750mm Hg, 800mm Hg, or 850mm Hg.

Preferably, the curing time is 0.5 to 6 hours, and may be, for example, 0.75 hour, 1 hour, 1.25 hour, 1.5 hour, 1.75 hour, 2 hours, 2.25 hours, 2.5 hours, 2.75 hours, 3 hours, 3.25 hours, 3.5 hours, 3.75 hours, 4 hours, 4.25 hours, 4.5 hours, 4.75 hours, 5 hours, 5.25 hours, 5.5 hours, or 5.75 hours, etc.

In a sixth aspect, the present invention provides a printed wiring board comprising at least one prepreg according to the third aspect or a metal-foil-clad laminate according to the fifth aspect.

Compared with the prior art, the invention has the following beneficial effects:

(1) The resin glue solution provided by the invention comprises a resin composition and a solvent, wherein the resin composition is a dicyandiamide-cured epoxy resin system, and a mixed solvent containing a polyol ether solvent and dimethyl sulfoxide is matched for use, so that dicyandiamide can be fully dissolved to form a uniform and stable glue solution, the separation of dicyandiamide in subsequent processing is avoided, and the problems of nitrogen oxide in the exhaust tail gas of an incinerator and DMF (dimethyl formamide) residue in a laminated metal sheet in the preparation process are effectively solved.

(2) The resin glue solution has good processability through screening of the solvent and compounding of the solvent and the resin composition, and the cured product has high glass transition temperature, good heat resistance and improved adhesive force with the metal foil. The prepreg and the metal foil-clad laminate prepared by the resin glue solution have good appearance, no apparent defects such as colloidal particles, bubbles and the like, the glass transition temperature of the metal foil-clad laminate reaches 137.5-141.1 ℃, the thermal decomposition temperature is higher than 310 ℃, the peel strength is 1.41-1.48N/mm, and the prepreg and the metal foil-clad laminate have better heat resistance and reliability and fully meet the application requirements of high-performance printed circuit boards.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

Example 1

The resin glue solution comprises the following components in parts by weight: 100 parts of an epoxy resin (KEB-3165 from Kolon Chemical company, epoxy equivalent weight 213 g/eq), 2.6 parts of dicyandiamide, 0.05 part of curing accelerator 2-MI (2-methylimidazole), and 22.5 parts of a solvent; wherein the solvent is a mixture of propylene glycol monomethyl ether and dimethyl sulfoxide (DMSO) in a mass ratio of 9.

The preparation method of the resin glue solution comprises the following steps:

(1) Mixing dicyandiamide with a solvent to obtain a dicyandiamide pre-solution with the dicyandiamide mass percentage of 10%, wherein the dissolving condition is good, and precipitates do not appear at the bottom;

(2) And (2) adding epoxy resin into the stirring kettle, pumping the dicyandiamide pre-solution obtained in the step (1), adding a curing accelerator, and uniformly mixing to obtain the resin glue solution.

A prepreg and a metal foil-clad laminate are specifically prepared by the following steps:

(A) Dipping a reinforcing material (7628 glass fiber cloth) into the resin glue solution provided by the embodiment, processing the reinforcing material dipped in the resin glue solution by a vertical gluing machine, controlling the rotating speed of a metering shaft of the vertical gluing machine to be 1.8m/min, the vehicle speed to be 10m/min, the wind temperature to be 150 ℃ and the oil temperature to be 180 ℃ to obtain a prepreg, wherein the average thickness of the prepreg is 0.2mm;

(B) Laminating 8 prepregs obtained in the step (A) among 2 copper foils with the thickness of 18 microns, and performing hot pressing and curing in a vacuum hot press to obtain a copper clad laminate with the thickness of 1.6 mm; the specific conditions for curing are as follows:

temperature program: magnification 30min at 130 ℃, magnification 30min at 155 ℃, magnification 60min at 190 ℃, magnification 60min at 220 ℃;

pressure program: 15kgf/cm ² ×30min，25kgf/cm ² ×30min，30kgf/cm ² ×120min；

Vacuum degree program: 30mm Hg × 120min,800mm Hg × 60min.

Example 2

A resin cement which differs from example 1 only in that the solvent is a mixture of propylene glycol monoethyl ether and DMSO in a mass ratio of 6.5; the other components and amounts were the same as in example 1.

A prepreg and a metal-clad laminate, which differ from example 1 only in that the resin paste in step (a) is the resin paste provided in this example; other materials and preparation processes were the same as in example 1.

Example 3

A resin cement solution which differs from example 1 only in that the solvent is a mixture of propylene glycol monomethyl ether and DMSO in a mass ratio of 5; the other components and amounts were the same as in example 1.

Example 4

A resin cement which differs from example 1 only in that the solvent is a mixture of propylene glycol monomethyl ether, DMSO and Dimethylformamide (DMF) in a mass ratio of 8; the other components and amounts were the same as in example 1.

Example 5

A resin cement solution which differs from example 1 only in that the solvent is a mixture of propylene glycol monomethyl ether and DMSO in a mass ratio of 9.5; the other components and amounts were the same as in example 1.

Example 6

A resin cement solution which differs from example 1 only in that the solvent is a mixture of propylene glycol monomethyl ether and DMSO in a mass ratio of 4; the other components and amounts were the same as in example 1.

Comparative example 1

A resin cement differing from example 1 only in that the solvent was DMF; the other components and amounts were the same as in example 1.

A prepreg and a metal-foil-clad laminate differing from example 1 only in that the resin paste in step (a) was the resin paste provided in this comparative example; other materials and preparation processes were the same as in example 1.

Comparative example 2

A resin cement which differs from example 1 only in that the solvent is a mixture of 1, 4-dioxane and DMSO in a mass ratio of 6.5; the other components and amounts were the same as in example 1.

A prepreg and a metal-clad laminate, which differ from example 1 only in that the resin paste in step (a) is the resin paste provided in this comparative example; other materials and preparation processes were the same as in example 1.

The performance of the metal foil-clad laminates prepared from the prepregs provided in examples 1 to 6 and comparative examples 1 to 2 was tested, and the specific test method was as follows:

(1) Glass transition temperature T _g : using a Differential Scanning Calorimetry (DSC), according to the DSC test method specified by IPC-TM-6502.4.24;

(2) Thermal decomposition temperature T _d : testing according to the method specified in IPC-TM-650.4.24.6;

(3) Thermal stress: taking 3 samples to be measured with copper foils on both sides, cutting the samples into the size of 50mm multiplied by 50mm, placing the samples on the surface of solder tin at 288 ℃, and observing the layering or foaming time;

(4) Peel strength PS: testing according to the method specified in IPC-TM-650.4.9;

(5) DMF content in laminate: detection by a third party of the SGS laboratory;

(6) Concentration of nitrogen oxides in exhaust gas discharged from an incinerator: sampling according to the method specified in HJ 732, and testing according to the method specified in HJ 692;

(7) Prepreg appearance: the appearance of the prepreg was visually observed for the presence of defects such as bubbles and colloidal particles.

The specific test results and Dicyandiamide (DICY) dissolution during prepreg production are shown in table 1:

TABLE 1

As can be seen from the test data in table 1, the resin pastes provided in examples 1 to 4 produced metal-clad laminates having a glass transition temperature of 137.5 to 141.1 ℃, a thermal decomposition temperature of 310.4 to 311.6 ℃, and a peel strength of 1.41 to 1.48N/mm, which are superior in heat resistance and reliability, as compared to the resin paste using DMF as a solvent in comparative example 1. As can be seen from parallel comparison of examples 1 to 4, T of the laminate sheet increases with the content of the polyol-based ether solvent in the solvent _g Gradually lifting; the synergistic combination of DMSO and the polyol ether-based solvent further improved the adhesive strength between the cured product and the metal foil, and increased the peel strength of the metal foil-clad laminate, and the solvent of example 3 had a higher DMSO content, and therefore, the peel strength was also the greatest. The resin glue solutions of examples 1 to 3 do not contain nitrogen solvent, and the nitrogen oxide in the exhaust gas discharged from the incinerator is only 17 to 22mg/m ³ (the nitrogen in the air is burnt and cracked at high temperature by an incinerator to generate trace nitrogen oxides); the solvent of the resin dope of example 4 contained 10% DMF and the metal-clad laminate contained 302ppm DMF residue (satisfying the requirement of DMF residue < 1000 ppm), but the concentration of nitrogen oxides in the incinerator exhaust gas was still high. Meanwhile, the DMSO with a specific ratio is cooperated with the polyol ether solvent to obtain an ideal resin glue solution, if the DMSO content in the solvent is too low (example 5),the dicyandiamide is easily separated out from the resin glue solution in the using process of the resin glue solution, so that the heat resistance is obviously reduced, and a precise filter is blocked, so that the normal production is influenced; if the DMSO content in the solvent is too high (example 6), volatile residue in the produced prepreg is high, and heat resistance of the metal foil laminate produced from the corresponding prepreg is also significantly reduced.

In comparative example 1, DMF was used as a solvent to prepare a resin solution, a prepreg and a metal-clad laminate, residual DMF in the metal-clad laminate was excessive, and nitrogen oxides in the exhaust gas of an incinerator was as high as 1941mg/m ³ And the glass transition temperature, the thermal decomposition temperature and the peeling strength of the laminated board are lower. In comparative example 2, the cyclic ether compound 1, 4-dioxane and DMSO are compounded, so that the product has excellent heat resistance and reliability, and meets the environmental protection requirement, but the appearance of the produced prepreg has a 'colloidal particle' defect, and a metal foil laminated board produced by the corresponding prepreg easily has a 'light concave' defect.

The applicant states that the present invention is described by the above embodiments of a resin paste, a prepreg and a metal foil-clad laminate, but the present invention is not limited to the above embodiments, that is, it is not intended that the present invention is necessarily implemented by the above embodiments. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.

Claims

1. The resin glue solution is characterized by comprising a resin composition and a solvent;

the resin composition comprises the following components in parts by weight: 80 to 120 parts of epoxy resin, 0.5 to 5 parts of dicyandiamide and 0.001 to 2 parts of curing accelerator;

the solvent is a mixture of a polyol ether solvent and dimethyl sulfoxide, and the mass percentage of the polyol ether solvent in the solvent is 50-90%;

or the solvent is a mixture of a polyol ether solvent, dimethyl sulfoxide and dimethylformamide, the mass percentage of the polyol ether solvent in the solvent is 50-90%, the mass percentage of the dimethyl sulfoxide in the solvent is 10-50%, the mass percentage of the dimethylformamide in the solvent is less than or equal to 10%, and the total mass of the polyol ether solvent, the dimethyl sulfoxide and the dimethylformamide is 100%;

the solid content of the resin glue solution is 40-85%;

the epoxy equivalent of the epoxy resin is 120 to 520 g/eq.

2. The resin glue solution of claim 1, wherein the epoxy resin comprises any one of or a combination of at least two of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, novolac epoxy resin, biphenyl type epoxy resin, or dicyclopentadiene type epoxy resin.

3. The resin glue solution according to claim 1, wherein the curing accelerator comprises any one or a combination of at least two of imidazole curing accelerators, organic phosphine curing accelerators, organic amine curing accelerators, peroxides or organic metal salts.

4. The resin glue solution according to claim 3, wherein the imidazole-based curing accelerator comprises any one of 2-methylimidazole, 2-methyl-4-ethylimidazole, 2-phenylimidazole or 2-undecylimidazole or a combination of at least two of the 2-methylimidazole, the 2-methyl-4-ethylimidazole, the 2-phenylimidazole and the 2-undecylimidazole.

5. The resin cement as claimed in claim 3, wherein the organic phosphine curing accelerator comprises any one or a combination of at least two of tributyl phosphine, triphenyl phosphine or tripropyl phosphine.

6. The resin glue solution of claim 3, wherein the organic amine curing accelerator is a tertiary amine compound.

7. The resin cement as claimed in claim 6, wherein the organic amine curing accelerator is benzyl dimethyl amine.

8. The resin cement according to claim 1, wherein the polyol ether solvent includes any one or a combination of at least two of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol dimethyl ether.

9. The resin adhesive solution according to claim 1, wherein the solvent is a mixture of a polyol ether solvent and dimethyl sulfoxide, and the mass percentage of the dimethyl sulfoxide in the solvent is 10 to 50%.

10. The resin glue solution according to claim 1, wherein the mass percentage of the dimethylformamide in the solvent is less than or equal to 5%.

11. A method for preparing the resin glue solution as claimed in any one of claims 1 to 10, wherein the method comprises the following steps:

12. The preparation method according to claim 11, wherein the mass percentage of dicyandiamide in the dicyandiamide pre-solution in the step (1) is 7 to 12%.

13. The method of claim 11, wherein the mixing in step (2) is performed by: and pumping the dicyandiamide pre-solution into epoxy resin, adding a curing accelerator, and uniformly dispersing to obtain the resin glue solution.

14. A prepreg comprising a reinforcing material, and a resin composition adhered to the reinforcing material; the resin composition is obtained by impregnating the resin glue solution according to any one of claims 1 to 10 and drying the resin glue solution.

15. The prepreg of claim 14, wherein the reinforcing material comprises any one of glass fiber cloth, organic fiber cloth, glass fiber paper, or organic fiber paper.

16. A laminate comprising at least one sheet of prepreg according to claim 14 or 15.

17. A metal-clad laminate comprising at least one prepreg according to claim 14 or 15 and a metal foil disposed on one or both sides of the prepreg.

18. The metal-clad laminate of claim 17 wherein the metal foil is a copper foil.

19. A printed wiring board comprising at least one prepreg according to claim 14 or 15 or a metal-foil-clad laminate according to claim 17 or 18.