An environmentally friendly and reliable halogen-free copper clad laminate and its preparation process

Abstract

The present invention relates to the technical field of copper clad laminate manufacturing, specifically to an environmentally friendly and reliable halogen-free copper clad laminate and its preparation process. The present invention first mixes an organic solvent, a curing agent, and an accelerator evenly, then adds a resin and stirs evenly, and finally adds modified silicon micropowder and modified aluminum hydroxide and mixes evenly. After efficient shearing and emulsification, an adhesive for electronic glass fiber cloth is obtained; the adhesive is applied to the surface of the glass fiber cloth and baked to obtain a semi-solid sheet; the semi-solid sheets are stacked and covered with copper foil on both sides, and a halogen-free copper clad laminate is obtained through hot pressing and cold pressing processes. The halogen-free copper clad laminate prepared by the present invention not only has excellent heat resistance and flame retardant properties, but also has environmental protection, thereby protecting the safety and reliability of electronic components.

Description

Technical Field

[0001] The present invention relates to the technical field of copper clad laminate manufacturing, in particular to an environmentally friendly and reliable halogen-free copper clad laminate and a preparation process thereof. Background Art

[0002] With growing environmental awareness and increasingly stringent environmental regulations, the environmental requirements for materials and processes used in electronic products are becoming increasingly stringent. Copper-clad laminates (CCLs), made from fiberglass cloth, epoxy resin, and halogen-containing flame retardants, are a key substrate for printed circuit boards (PCBs) widely used in electronic products. However, traditional CCLs often contain halogen compounds, such as bromides or chlorides, which can release harmful gases and wastewater during production and processing, posing potential risks to the environment and human health. These added flame retardants release toxic gases when the laminates are burned. To avoid the adverse effects of these toxic substances, developing environmentally friendly CCLs and improving product reliability have become urgent priorities.

[0003] Therefore, we propose an environmentally friendly and reliable halogen-free copper clad laminate and its preparation process. Summary of the Invention

[0004] The object of the present invention is to provide an environmentally friendly and reliable halogen-free copper clad laminate and a preparation process thereof, so as to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A process for preparing an environmentally friendly and reliable halogen-free copper clad laminate comprises the following steps:

[0007] The organic solvent, curing agent and accelerator are mixed evenly, heated to 20-40°C, stirred for 50-60 minutes, phosphorus-containing epoxy resin, phenolic epoxy resin, isocyanate-modified epoxy resin, benzoxazine resin, phosphorus-containing phenolic resin, and tetrafunctional epoxy resin are added, stirred for 50-60 minutes, and modified silica powder and modified aluminum hydroxide are added. After stirring evenly, the mixture is sheared at a shear rate of 1000-5000 rad / min for 40-60 minutes and emulsified for 130-150 minutes to prepare an adhesive for electronic glass fiber cloth.

[0008] Step S2: uniformly coating the electronic glass fiber cloth with glue on the surface of the electronic glass fiber cloth, and baking at 215-225° C. for 90-100 seconds to obtain a prepreg;

[0009] Step S3: stack 4-8 prepregs to obtain a composite sheet, cover the upper and lower surfaces of the composite sheet with a copper foil, and perform hot pressing and cold pressing to obtain a halogen-free copper clad laminate.

[0010] Furthermore, in step S1, the adhesive for electronic glass fiber cloth includes the following weight percentages: 10-15wt% organic solvent, 1.2-3.4wt% curing agent, 0.281-0.322wt% accelerator, 32-34wt% phosphorus-containing epoxy resin, 2-4wt% phenolic epoxy resin, 8-10wt% isocyanate-modified epoxy resin, 9-11wt% benzoxazine resin, 12-14wt% phosphorus-containing phenolic resin, 0.1-0.3wt% tetrafunctional epoxy resin, 8-12wt% modified silica powder, and 5-9wt% modified aluminum hydroxide.

[0011] Furthermore, the organic solvent is composed of butanone and dimethylformamide in a mass ratio of 1:(1-2).

[0012] Furthermore, the curing agent is composed of a dicyandiamide curing agent and a phenolic curing agent in a mass ratio of 1: (6.0-7.5).

[0013] Furthermore, the accelerator is composed of 2-methylimidazole and 4,4'-diaminodiphenyl sulfone in a mass ratio of 1:(280-320).

[0014] Furthermore, the phosphorus-containing epoxy resin is a DOPO-NQ type epoxy resin.

[0015] Furthermore, the novolac epoxy resin is bisphenol A novolac epoxy resin.

[0016] Furthermore, the preparation process of the modified silicon micropowder is as follows:

[0017] Step (1): mixing silicon micropowder, sodium hydroxide solution and glycerol uniformly, ultrasonically treating for 1-3 hours, washing, filtering, and drying at 100-120° C. for 2-3 hours to obtain surface-activated silicon micropowder;

[0018] Step (2): adding the surface-activated silicon micropowder to a mixed solution of ethanol and deionized water, ultrasonically dispersing for 30-50 minutes, then adding 3-glycidyloxypropyltrimethoxysilane and (aminoethylaminomethyl)phenethyltrimethoxysilane and mixing evenly, stirring in a 70-80°C water bath for 1-2 hours, cooling to room temperature, washing, filtering, and drying at 80-100°C for 12-24 hours to obtain pretreated silicon micropowder;

[0019] Step (3): Under nitrogen protection, the pretreated silicon micropowder and N-(hydroxymethyl) acrylamide are mixed evenly, deionized water is added and mixed evenly, cerium nitrate ammonium is added dropwise for 1-2 hours, the temperature is raised to 30-40°C, the reaction is carried out for 2-4 hours, the mixture is filtered, washed, and dried at 80-100°C for 12-24 hours to obtain modified silicon micropowder.

[0020] In the above technical solution, the surface of the silicon micropowder is treated with sodium hydroxide solution and glycerol to obtain surface-activated silicon micropowder, whose surface hydrophilicity is enhanced and the number of silanol groups is increased; then, 3-glycidyloxypropyltrimethoxysilane and (aminoethylaminomethyl)phenethyltrimethoxysilane are used to treat the surface of the silicon micropowder, and the silanol groups on the surface of the silicon micropowder can undergo a dehydration condensation reaction with the hydroxyl groups on the hydrolyzed silane molecules, introducing epoxy groups, amino groups and benzene ring structures, further improving the heat resistance of the silicon micropowder, enabling it to maintain stability in a high temperature environment, and at the same time, reducing the interaction between spherical silicon micropowders, effectively preventing the occurrence of agglomeration; finally, under the action of an initiator, the amino groups on the surface of the pretreated silicon micropowder can undergo a graft polymerization reaction with the double bond of N-(hydroxymethyl)acrylamide, achieving a double-layer coating on the surface of the silicon micropowder, and obtaining modified silicon micropowder.

[0021] Furthermore, in step (1), the mass ratio of silicon micropowder to sodium hydroxide solution and glycerol is 1:(1-2):(5-8).

[0022] Furthermore, the concentration of the sodium hydroxide solution in step (1) is 5-7 mol / L.

[0023] Furthermore, in step (2), the mass ratio of ethanol to deionized water is 1:(9-11).

[0024] Furthermore, the mass of the surface-activated silicon micropowder in step (2) is 5-10% of the mass of the mixed solution.

[0025] Furthermore, in step (2), the mass of 3-glycidyloxypropyltrimethoxysilane is 0.5-1.0% of the mass of the mixed solution.

[0026] Furthermore, in step (2), the mass of (aminoethylaminomethyl)phenethyltrimethoxysilane is 1-2% of the mass of the mixed solution.

[0027] Furthermore, in step (3), the mass ratio of the pretreated silicon powder to N-(hydroxymethyl)acrylamide is 1:(0.03-0.05).

[0028] Furthermore, the mass of the deionized water in step (3) is 6-8 times the mass of the pretreated silicon micropowder.

[0029] Furthermore, the mass of the cerium ammonium nitrate in step (3) is 0.3-0.5% of the mass of the pretreated silicon powder.

[0030] Furthermore, the preparation process of the modified aluminum hydroxide is as follows:

[0031] Step a: Under nitrogen protection, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and dimethylamide are mixed evenly, (4-vinylphenyl)trimethoxysilane is added and mixed evenly, and the mixture is heated to 60-70° C., and azobisisobutyronitrile is added dropwise over 1-2 hours. The mixture is then heated to 75-85° C. and reacted for 8-10 hours. The mixture is cooled to room temperature, washed, filtered, and dried to obtain DOPO-based siloxane.

[0032] Step b: Aluminum hydroxide and deionized water were mixed evenly, concentrated hydrochloric acid was slowly added dropwise to adjust the pH to 4.8-5.3, the mixture was heated to 60-70° C., a mixture of DOPO-based siloxane and anhydrous ethanol was added dropwise over 1-2 hours, and the mixture was reacted for 10-12 hours. After washing, filtration, and drying, substance A was obtained;

[0033] Step c: Mix substance A, anhydrous ethanol and deionized water evenly, add ethyl orthosilicate dropwise for 1-2 hours, adjust the pH to 9-10 with ammonia water, heat to 40-50°C, react for 3-4 hours, cool to room temperature, centrifuge, wash and dry to obtain modified aluminum hydroxide.

[0034] In the above technical solution, the PH bond in 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide reacts with the double bond in (4-vinylphenyl)trimethoxysilane to introduce the phosphorus-containing compound DOPO structure to prepare DOPO-based siloxane; the DOPO-based siloxane undergoes a hydrolysis reaction to produce hydroxyl groups, which can form hydrogen bonds with hydroxyl-containing aluminum hydroxide, and then dehydrates to form covalent bonds, introducing P and Si elements on the surface of the aluminum hydroxide to obtain DOPO-based siloxane-modified aluminum hydroxide, recorded as substance A; finally, a SiO2 layer is further coated on the surface of substance A to prepare modified aluminum hydroxide.

[0035] Furthermore, in step a, the mass ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to dimethylamide is 1:(2-4).

[0036] Furthermore, in step a, the mass ratio of (4-vinylphenyl)trimethoxysilane to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:(1-1.5).

[0037] Furthermore, the mass of azobisisobutyronitrile in step a is 0.2-0.6% of the mass of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0038] Furthermore, in step b, the mass ratio of aluminum hydroxide to deionized water is 1:(4-5).

[0039] Furthermore, in step b, the mass of the DOPO-based siloxane is 3-5% of the mass of the aluminum hydroxide, and the volume ratio of the DOPO-based siloxane to anhydrous ethanol is 1:(1-1.5).

[0040] Furthermore, in step c, the mass ratio of substance A to anhydrous ethanol and deionized water is 1:(2-4):(10-15).

[0041] Furthermore, in step c, the mass of ethyl orthosilicate is 2-3 times the mass of substance A.

[0042] Furthermore, in step S1, the solid content of the glue for electronic glass fiber cloth is 66%, the viscosity is 20 seconds for coating four cups, and the gelation time is 210 seconds at 171°C.

[0043] Furthermore, in step S2, the electronic glass fiber cloth is impregnated in a vertical gluing machine before coating.

[0044] Furthermore, the coating process conditions in step S2 are as follows: controlling the adhesive content of the prepreg to be 365-370 g / m2.

[0045] Furthermore, the hot pressing and cold pressing process conditions in step S3 are: hot pressing temperature 230-240°C, hot pressing pressure 2-3MPa, hot pressing vacuum 15-20Torr, hot pressing time 150-180min; cold pressing temperature 20-25°C, cold pressing pressure 1-2MPa, cold pressing time 60-80min.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. The present invention provides an environmentally friendly and reliable halogen-free copper clad laminate and a preparation process thereof. The surface of silicon micropowder is treated with sodium hydroxide solution and glycerol to obtain surface-activated silicon micropowder, whose surface hydrophilicity is enhanced and the number of silanol groups is increased; 3-glycidyloxypropyltrimethoxysilane and (aminoethylaminomethyl)phenethyltrimethoxysilane are then used to surface-treat the silicon micropowder. The silanol groups on the surface of the silicon micropowder can undergo a dehydration condensation reaction with the hydroxyl groups on the hydrolyzed silane molecules, introducing epoxy groups, amino groups and benzene ring structures, further improving the heat resistance of the silicon micropowder, enabling it to maintain stability in a high-temperature environment, and at the same time, reducing the interaction between the silicon micropowders and effectively preventing the occurrence of agglomeration; finally, under the action of an initiator, the amino groups on the surface of the pretreated silicon micropowder can undergo a graft polymerization reaction with the double bonds of N-(hydroxymethyl)acrylamide, achieving a double-layer coating on the surface of the silicon micropowder, and obtaining modified silicon micropowder.

[0048] 2. The present invention provides an environmentally friendly and reliable halogen-free copper clad laminate and a preparation process thereof. The PH bond in 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide reacts with the double bond in (4-vinylphenyl)trimethoxysilane to introduce a phosphorus-containing compound DOPO structure to prepare a DOPO-based siloxane; the DOPO-based siloxane undergoes a hydrolysis reaction to generate hydroxyl groups, which can form hydrogen bonds with hydroxyl-containing aluminum hydroxide, and then is dehydrated to form covalent bonds, thereby introducing P and Si elements on the surface of the aluminum hydroxide to prepare substance A; finally, a SiO2 layer is further coated on the surface of substance A to prepare a modified aluminum hydroxide; not only is the flame retardant performance of the aluminum hydroxide improved, but its dispersion performance is also improved, and it is environmentally friendly, reducing the negative impact on the environment.

[0049] 3. The present invention provides an environmentally friendly and reliable halogen-free copper-clad laminate and its preparation process. The copper-clad laminate is mainly composed of a self-extinguishing phosphorus-containing (DOPO-NQ) epoxy resin, bisphenol A-type phenolic epoxy ester, isocyanate-modified epoxy resin, benzoxazine resin, phosphorus-containing phenolic resin, phenolic curing agent, tetrafunctional epoxy resin, accelerator DDS (4,4'-diaminodiphenylmethane), 2MZ (2-methylimidazole), and a certain amount of harmless modified metal hydroxide such as aluminum hydroxide (ATH), modified silicon powder, and a small amount of DICY (dicyandiamide). The copper-clad laminate has good flame retardancy and heat resistance, moisture resistance, excellent electrical properties, and good processing properties. These excellent properties can replace the currently widely used FR-4 printed circuit substrate. In the manufacture of copper-clad laminates, the use of DICY and PN (phenolic) curing agents in conjunction with self-extinguishing epoxy resins, modified silica powder, and modified ATH significantly enhances flame retardancy and heat resistance while also being environmentally friendly. This process helps enhance the performance and sustainable development of copper-clad laminates while protecting the safety and reliability of electronic components. DETAILED DESCRIPTION

[0050] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0051] In this embodiment, the dicyandiamide curing agent is from Zhengzhou Guanda Chemical Products Co., Ltd.; the phenolic curing agent is model NL-1, which is from Henan Binhai Industrial Co., Ltd.; the phosphorus-containing epoxy resin is DOPO-NQ type epoxy resin, with an epoxy equivalent of 320-340 g / eq, which is from Suzhou Senfida Chemical Co., Ltd.; the phenolic epoxy resin is bisphenol A type phenolic epoxy resin, brand E-51, with an epoxy equivalent of 184-195 g / mol, which is from Nantong Xingchen Synthetic Materials Co., Ltd.; the isocyanate-modified epoxy resin is brand A-IME, with an epoxy equivalent of 292-345 g / eq, which is from Jiangshan Chemical (Shanghai) Co., Ltd.; the benzoxazine resin is brand CB9660, a halogen-free flame retardant, which is from Chengdu Keyi Polymer Technology Co., Ltd.; phosphorus-containing phenolic resin: sourced from Shandong Mobai Chemical Co., Ltd.; tetrafunctional epoxy resin: model AG80, epoxy equivalent 115-130g / eq, sourced from Jining Benoke Biotechnology Co., Ltd.; silicon micropowder: spherical silicon micropowder, particle size 3-12μm, purity ≥99.99%, sourced from Guangdong Yongfeng Chemical Co., Ltd.; aluminum hydroxide: brand AH-3, particle size 0.5-10μm, purity ≥99.99%, sourced from Shenzhen Jingcai Chemical Co., Ltd.; electronic glass fiber cloth: specification 2116, thickness 0.08mm, sourced from Keli New Materials Co., Ltd.; copper foil: 0.5 ounces electrolytic copper foil, sourced from Shenzhen Jintongdu Metal Materials Co., Ltd.

[0052] In the following examples and comparative examples, 1 part is equal to 10 g.

[0053] Example 1: A process for preparing an environmentally friendly and reliable halogen-free copper clad laminate, comprising the following steps:

[0054] Step S1: 5 parts of butanone, 5 parts of dimethylformamide, 0.2 parts of dicyandiamide curing agent, 1.2 parts of phenolic curing agent, 0.28 parts of 4,4'-diaminodiphenyl sulfone, and 0.001 parts of 2-methylimidazole are mixed uniformly, heated to 20°C, and stirred for 50 minutes; 32 parts of phosphorus-containing epoxy resin, 2 parts of phenolic epoxy resin, 8 parts of isocyanate-modified epoxy resin, 9 parts of benzoxazine resin, 12 parts of phosphorus-containing phenolic resin, and 0.1 parts of tetrafunctional epoxy resin are added, and stirred for 50 minutes. Then, 8 parts of modified silica powder and 5 parts of modified aluminum hydroxide are added, and after uniform stirring, the mixture is sheared at a shear rate of 1000 rad / min for 40 minutes and emulsified for 130 minutes to prepare an adhesive for electronic glass fiber cloth;

[0055] Step S2: evenly coating the surface of the electronic glass fiber cloth with glue (the electronic glass fiber cloth is impregnated in a vertical glue applicator before coating, and the glue content of the prepreg is controlled to be 365g / ㎡), and baking at 215°C for 90s to obtain a prepreg;

[0056] Step S3: stacking four prepregs to obtain a composite sheet, covering the upper and lower surfaces of the composite sheet with a copper foil, and performing hot pressing and cold pressing (hot pressing temperature: 230°C, hot pressing pressure: 2 MPa, hot pressing vacuum: 15 Torr, hot pressing time: 150 min; cold pressing temperature: 20°C, cold pressing pressure: 1 MPa, cold pressing time: 60 min) to obtain a halogen-free copper clad laminate;

[0057] The preparation process of modified silicon micropowder is as follows:

[0058] Step (1): 8 parts of silicon micropowder, 8 parts of 5 mol / L sodium hydroxide solution, and 40 parts of propylene glycol were mixed uniformly, ultrasonically treated for 1 hour, washed, filtered, and dried at 100° C. for 2 hours to obtain surface-activated silicon micropowder;

[0059] Step (2): 8 parts of surface-activated silicon micropowder are added to a mixed solution of 16 parts of ethanol and 144 parts of deionized water, ultrasonically dispersed for 30 minutes, and then 0.8 parts of 3-glycidyloxypropyltrimethoxysilane and 1.6 parts of (aminoethylaminomethyl)phenethyltrimethoxysilane are added and mixed evenly, stirred in a 70°C water bath for 1 hour, cooled to room temperature, washed, filtered, and dried at 80°C for 12 hours to obtain pretreated silicon micropowder;

[0060] Step (3): Under nitrogen protection, 8 parts of pretreated silicon micropowder and 0.24 parts of N-(hydroxymethyl) acrylamide were mixed evenly, 48 parts of deionized water were added and mixed evenly, 0.024 parts of cerium nitrate ammonium were added dropwise, and the mixture was added over a period of 1 hour. The mixture was heated to 30°C and reacted for 2 hours. The mixture was filtered, washed, and dried at 80°C for 12 hours to obtain modified silicon micropowder.

[0061] The preparation process of modified aluminum hydroxide is as follows:

[0062] Step a: Under nitrogen protection, 0.15 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 0.3 parts of dimethylamide were mixed evenly, 0.15 parts of (4-vinylphenyl)trimethoxysilane were added and mixed evenly, and the mixture was heated to 60° C., 0.0003 parts of azobisisobutyronitrile were added dropwise over 1 hour, and the mixture was heated to 75° C. and reacted for 8 hours. The mixture was cooled to room temperature, washed, filtered, and dried to obtain DOPO-based siloxane;

[0063] Step b: 5 parts of aluminum hydroxide and 20 parts of deionized water were mixed evenly, concentrated hydrochloric acid was slowly added dropwise to adjust the pH to 4.8, the mixture was heated to 60° C., and a mixture of 0.15 parts of DOPO-based siloxane and 0.15 parts of anhydrous ethanol was added dropwise over 1 hour. The mixture was reacted for 10 hours, and then washed, filtered, and dried to obtain substance A.

[0064] Step c: Mix 5 parts of substance A, 10 parts of anhydrous ethanol and 50 parts of deionized water, add 10 parts of ethyl orthosilicate dropwise for 1 hour, adjust the pH to 9 with ammonia water, heat to 40°C, react for 3 hours, cool to room temperature, centrifuge, wash and dry to obtain modified aluminum hydroxide.

[0065] Example 2: A process for preparing an environmentally friendly and reliable halogen-free copper clad laminate, comprising the following steps:

[0066] Step S1: 6 parts of butanone, 8 parts of dimethylformamide, 0.3 parts of dicyandiamide curing agent, 2 parts of phenolic curing agent and 0.3 parts of 4,4'-diaminodiphenyl sulfone, and 0.001 parts of 2-methylimidazole are mixed uniformly, heated to 30°C, and stirred for 55 minutes; 33 parts of phosphorus-containing epoxy resin, 3 parts of phenolic epoxy resin, 9 parts of isocyanate-modified epoxy resin, 10 parts of benzoxazine resin, 13 parts of phosphorus-containing phenolic resin, and 0.2 parts of tetrafunctional epoxy resin are added, and stirred for 55 minutes. Then, 10 parts of modified silica powder and 8 parts of modified aluminum hydroxide are added, and after uniform stirring, the mixture is sheared at a shear rate of 3000 rad / min for 50 minutes and emulsified for 140 minutes to prepare an adhesive for electronic glass fiber cloth;

[0067] Step S2: evenly coating the surface of the electronic glass fiber cloth with glue (the electronic glass fiber cloth is impregnated in a vertical glue applicator before coating, and the glue content of the prepreg is controlled to be 368g / ㎡), and baking at 220°C for 95s to obtain a prepreg;

[0068] Step S3: 6 prepregs were stacked to obtain a composite sheet, and a copper foil was applied to the upper and lower surfaces of the composite sheet, followed by hot pressing and cold pressing (hot pressing temperature: 235°C, hot pressing pressure: 2.5 MPa, hot pressing vacuum: 18 Torr, hot pressing time: 170 min; cold pressing temperature: 22°C, cold pressing pressure: 1.5 MPa, cold pressing time: 70 min) to obtain a halogen-free copper clad laminate.

[0069] The preparation process of modified silicon micropowder is as follows:

[0070] Step (1): 10 parts of silicon micropowder, 15 parts of 6 mol / L sodium hydroxide solution, and 60 parts of propylene glycol were mixed uniformly, ultrasonically treated for 2 hours, washed, filtered, and dried at 110° C. for 2.5 hours to obtain surface-activated silicon micropowder;

[0071] Step (2): adding 10 parts of surface-activated silicon micropowder to a mixed solution of 11 parts of ethanol and 121 parts of deionized water, ultrasonically dispersing for 40 minutes, then adding 1 part of 3-glycidyloxypropyltrimethoxysilane and 2 parts of (aminoethylaminomethyl)phenethyltrimethoxysilane and mixing evenly, stirring in a 75°C water bath for 1.5 hours, cooling to room temperature, washing, filtering, and drying at 90°C for 20 hours to obtain pretreated silicon micropowder;

[0072] Step (3): Under nitrogen protection, 10 parts of pretreated silicon micropowder and 0.4 parts of N-(hydroxymethyl) acrylamide were mixed evenly, 70 parts of deionized water were added and mixed evenly, 0.04 parts of cerium nitrate ammonium were added dropwise, and the mixture was added over a period of 1.5 hours. The mixture was heated to 35°C and reacted for 3 hours. The mixture was filtered, washed, and dried at 90°C for 20 hours to obtain modified silicon micropowder;

[0073] The preparation process of modified aluminum hydroxide is as follows:

[0074] Step a: Under nitrogen protection, 0.6 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 1.8 parts of dimethylamide were mixed evenly, 0.5 parts of (4-vinylphenyl)trimethoxysilane were added and mixed evenly, and the mixture was heated to 65° C., 0.0024 parts of azobisisobutyronitrile were added dropwise over 1.5 hours, and the mixture was heated to 80° C. and reacted for 9 hours. The mixture was cooled to room temperature, washed, filtered, and dried to obtain DOPO-based siloxane;

[0075] Step b: 8 parts of aluminum hydroxide and 36 parts of deionized water were mixed uniformly, concentrated hydrochloric acid was slowly added dropwise to adjust the pH to 5, the mixture was heated to 65° C., a mixture of 0.32 parts of DOPO-based siloxane and 0.4 parts of anhydrous ethanol was added dropwise over 1.5 hours, and the mixture was reacted for 11 hours. After washing, filtration, and drying, substance A was obtained;

[0076] Step c: 8 parts of substance A, 24 parts of anhydrous ethanol and 96 parts of deionized water were mixed evenly, 20 parts of ethyl orthosilicate were added dropwise over a period of 1.5 hours, the pH was adjusted to 9-10 with aqueous ammonia, the temperature was raised to 45°C, the reaction was continued for 3.5 hours, and the mixture was cooled to room temperature. After centrifugation, washing and drying, modified aluminum hydroxide was obtained.

[0077] Example 3: A process for preparing an environmentally friendly and reliable halogen-free copper clad laminate, comprising the following steps:

[0078] Step S1: 5 parts of butanone, 10 parts of dimethylformamide, 0.4 parts of dicyandiamide curing agent, 3 parts of phenolic curing agent, 0.4 parts of 4,4'-diaminodiphenyl sulfone, and 0.002 parts of 2-methylimidazole are mixed uniformly, heated to 40°C, and stirred for 60 minutes; 34 parts of phosphorus-containing epoxy resin, 4 parts of phenolic epoxy resin, 10 parts of isocyanate-modified epoxy resin, 11 parts of benzoxazine resin, 14 parts of phosphorus-containing phenolic resin, and 0.3 parts of tetrafunctional epoxy resin are added, and stirred for 60 minutes. Then, 12 parts of modified silica powder and 9 parts of modified aluminum hydroxide are added, and after uniform stirring, the mixture is sheared at a shear rate of 5000 rad / min for 60 minutes and emulsified for 150 minutes to prepare an adhesive for electronic glass fiber cloth;

[0079] Step S2: evenly coating the surface of the electronic glass fiber cloth with glue (the electronic glass fiber cloth is impregnated in a vertical glue applicator before coating, and the glue content of the prepreg is controlled to be 370g / ㎡), and baking at 225°C for 100s to obtain a prepreg;

[0080] Step S3: 8 prepregs are stacked to obtain a composite sheet, and a copper foil is applied to the upper and lower surfaces of the composite sheet, followed by hot pressing and cold pressing (hot pressing temperature: 240°C, hot pressing pressure: 3 MPa, hot pressing vacuum: 20 Torr, hot pressing time: 180 min; cold pressing temperature: 25°C, cold pressing pressure: 2 MPa, cold pressing time: 80 min) to obtain a halogen-free copper clad laminate.

[0081] The preparation process of modified silicon micropowder is as follows:

[0082] Step (1): 12 parts of silicon micropowder, 24 parts of 7 mol / L sodium hydroxide solution, and 96 parts of propylene glycol were mixed uniformly, ultrasonically treated for 3 hours, washed, filtered, and dried at 120° C. for 3 hours to obtain surface-activated silicon micropowder;

[0083] Step (2): adding 12 parts of surface-activated silicon micropowder to a mixed solution of 10 parts of ethanol and 110 parts of deionized water, ultrasonically dispersing for 50 minutes, then adding 1.2 parts of 3-glycidyloxypropyltrimethoxysilane and 2.4 parts of (aminoethylaminomethyl)phenethyltrimethoxysilane and mixing evenly, stirring in an 80°C water bath for 2 hours, cooling to room temperature, washing, filtering, and drying at 100°C for 24 hours to obtain pretreated silicon micropowder;

[0084] Step (3): Under nitrogen protection, 12 parts of pretreated silicon micropowder and 0.6 parts of N-(hydroxymethyl) acrylamide were mixed evenly, 96 parts of deionized water were added and mixed evenly, 0.06 parts of cerium nitrate amine were added dropwise, and the mixture was added over 2 hours. The mixture was heated to 40°C and reacted for 4 hours. The mixture was filtered, washed, and dried at 100°C for 24 hours to obtain modified silicon micropowder;

[0085] The preparation process of modified aluminum hydroxide is as follows:

[0086] Step a: Under nitrogen protection, 0.75 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 3 parts of dimethylamide were mixed evenly, 0.5 parts of (4-vinylphenyl)trimethoxysilane were added and mixed evenly, and the mixture was heated to 70° C., and azobisisobutyronitrile was added dropwise over 2 hours. The temperature was continued to rise to 85° C., and the reaction was continued for 10 hours. The mixture was cooled to room temperature, washed, filtered, and dried to obtain DOPO-based siloxane;

[0087] Step b: 9 parts of aluminum hydroxide and 45 parts of deionized water were mixed uniformly, concentrated hydrochloric acid was slowly added dropwise to adjust the pH to 5.3, the mixture was heated to 70° C., and a mixture of 0.45 parts of DOPO-based siloxane and 0.675 parts of anhydrous ethanol was added dropwise over 2 hours. The mixture was reacted for 12 hours, and then washed, filtered, and dried to obtain substance A.

[0088] Step c: Mix 9 parts of substance A, 36 parts of anhydrous ethanol and 135 parts of deionized water, add 27 parts of ethyl orthosilicate dropwise over 2 hours, adjust the pH to 10 with ammonia water, heat to 50°C, react for 4 hours, cool to room temperature, centrifuge, wash and dry to obtain modified aluminum hydroxide.

[0089] Comparative Example 1: The glue for electronic glass fiber cloth in step S1 includes the following mass percentages: 6 parts of butanone, 7 parts of dimethylformamide, 0.3 parts of dicyandiamide curing agent, 2 parts of phenolic curing agent, 0.35 parts of 4,4'-diaminodiphenyl sulfone, 0.0015 parts of 2-methylimidazole, 33 parts of phosphorus-containing epoxy resin, 3 parts of phenolic epoxy resin, 9 parts of isocyanate-modified epoxy resin, 10 parts of benzoxazine resin, 13 parts of phosphorus-containing phenolic resin, 0.2 parts of tetrafunctional epoxy resin, 2 parts of modified silicon powder, and 8 parts of modified aluminum hydroxide; compared with Example 2, 2 parts of modified silicon powder are added to Comparative Example 1, and the other steps and processes are the same as Example 2.

[0090] Comparative Example 2: The glue for electronic glass fiber cloth in step S1 includes the following mass percentages: 6 parts of butanone, 7 parts of dimethylformamide, 0.3 parts of dicyandiamide curing agent, 2 parts of phenolic curing agent, 0.35 parts of 4,4'-diaminodiphenyl sulfone, 0.0015 parts of 2-methylimidazole, 33 parts of phosphorus-containing epoxy resin, 3 parts of phenolic epoxy resin, 9 parts of isocyanate-modified epoxy resin, 10 parts of benzoxazine resin, 13 parts of phosphorus-containing phenolic resin, 0.2 parts of tetrafunctional epoxy resin, 10 parts of modified silica powder, and 1 part of modified aluminum hydroxide; compared with Example 2, 1 part of modified aluminum hydroxide is added in Comparative Example 2, and the other steps and processes are the same as those in Example 2.

[0091] Comparative Example 3: The glue for electronic glass fiber cloth in step S1 includes the following mass percentages: 6 parts of butanone, 7 parts of dimethylformamide, 0.3 parts of dicyandiamide curing agent, 2 parts of phenolic curing agent, 0.35 parts of 4,4'-diaminodiphenyl sulfone, 0.0015 parts of 2-methylimidazole, 33 parts of phosphorus-containing epoxy resin, 3 parts of phenolic epoxy resin, 9 parts of isocyanate-modified epoxy resin, 10 parts of benzoxazine resin, 13 parts of phosphorus-containing phenolic resin, 0.2 parts of tetrafunctional epoxy resin, 10 parts of modified silica powder, and 8 parts of aluminum hydroxide; compared with Example 2, Comparative Example 3 replaces the modified aluminum hydroxide with unmodified aluminum hydroxide of the same specification, and the other steps are the same as Example 2.

[0092] experiment

[0093] Experiment 1: Take the halogen-free copper clad laminate obtained in Example 2, prepare samples, test their properties and record the test results:

[0094] Peel strength was measured according to IPC-TM-650, Version 2.4.8, "Copper Clad Laminate Peel and Impact Test Method." The test procedure involved cutting the copper clad laminate into a 100 mm x 5 mm specimen. The specimen was peeled 12 mm from the peeling end, held with a clip, and the peel strength between the copper foil and the substrate was measured. The test was performed at a peel speed of 50 mm / min, a 90° peel angle, and a 25 mm peel distance.

[0095] Thermal stress was measured according to IPC-4103A 3.10.1.2. The following experimental steps were used: a 50 mm x 50 mm copper-clad laminate specimen was immersed in a 288°C tin bath until bubbles were observed, and the time data was recorded.

[0096] The Tg was determined by differential scanning calorimetry according to the standard 2.4.25 of IPC-TM-650. The experimental steps were as follows: the copper clad laminate sample had a mass of 15 mg and was heated in a nitrogen atmosphere at a heating rate of 20°C / min, starting at 40°C, and heated to 550°C, and the glass transition temperature (Tg) was recorded.

[0097] Pressure vessel test: Place a 50mm×50mm copper-clad laminate in a PCT high-pressure cooking pot, set the pressure to 105KPa, the time to 30 minutes, and the temperature to 260℃, and rate the pressure vessel based on its safety status.

[0098] Determine bow / warp according to IPC-TM-650 2.4.22. Experimental steps: Cut the copper clad laminate into a specimen with a length of 100 mm and a width of 25 mm. Use a measuring tool (such as a vernier caliper) to measure the bow / warp of the specimen.

[0099] Flame retardancy is measured according to the UL-94 standard vertical combustion method. The experimental steps are as follows: the copper clad laminate is cut into rectangular strips with a length of 125mm, a width of 13mm, and a thickness of 0.7mm. The lower end of the strip is ignited. The test equipment will record the burning process of the sample and classify it into different grades according to the performance: V-0 grade means that the material does not drip sparks, the burning process time is less than 10 seconds, and the flame height is less than 50mm; V-1 grade means that during the burning process, the flame height is less than 50mm, the burning time does not exceed 30 seconds, and there is no obvious dripping sparks.

[0100] The dielectric constant and dielectric loss were determined according to IPC TM-650 (2.5.5). The following experimental steps were used: a copper-clad laminate sample (10 mm x 10 mm) was mounted on an air substrate and measured using a Split Dielectric Resonator (SPDR) at a frequency of 10 GHz and 101 sampling points. The test was then started and the data was recorded.

[0101] The Z-axis thermal expansion coefficient was determined according to IPC-TM-6502.4.24 "Glass transition temperature and Z-axis thermal expansion coefficient (TMA method)". The experimental steps were as follows: a thermomechanical analysis instrument was used to perform thermal mechanical analysis on the adhesive, with nitrogen as the protective gas, a heating rate of 20°C / min, and a test temperature range of room temperature to 400°C.

[0102] The water absorption rate was determined according to IPC-TM-650 specification 2.6.2.1. The experimental steps were as follows: the copper clad laminate specimen was 50 mm × 50 mm in size. The specimen was baked at 120°C for 2 hours, and its weight M1 was measured. The specimen was then soaked in deionized water for 24 hours, and its weight M2 was measured again. The water absorption rate was calculated as (M2-M1) / M1.

[0103] Flexural strength was measured according to IPC-TM-650 2.4.4. The following experimental steps were used: Two specimens were cut transversely and two longitudinally from the copper-clad laminate to be tested. Each specimen was 25 mm long and 10 mm wide. The flexural strength was measured at room temperature using an electronic universal testing machine at a loading speed of 2 mm / min. Five specimens were tested per group, and the average value was taken to record the flexural strength data for both the fill (weft) and warp (warp) directions.

[0104] The surface resistivity and volume resistivity were measured according to the GB / T1410-2006 standard. The experimental steps were as follows: the copper clad laminate was made into a disc sample with a diameter of 100 mm and a thickness of 2 mm. After being placed in an environment with a room temperature of 25°C and a humidity of 50% for 48 hours, the surface resistance and volume resistivity were tested using a ZC-90 series high insulation resistance meter. Each sample was tested 3 times and the average value was taken.

[0105] Test results

[0106]

[0107]

[0108] According to the data in the above table, the following conclusions can be clearly drawn: the halogen-free copper clad laminate prepared by the present invention has excellent performance and improves the reliability of the product. After rigorous testing, all performance indicators of the board meet the requirements of the inspection standards.

[0109] Experiment 2: Take the halogen-free copper clad laminates obtained in Examples 1-3 and Comparative Examples 1-3, prepare samples, test their flame retardancy and thermal stress, and record the test results:

[0110]

[0111]

[0112] According to the data in the above table, we can clearly draw the following conclusions:

[0113] 1. Compared with implementations 1-3, the heat resistance of the product obtained in comparative example 1 decreased, indicating that the copper clad laminate prepared by adding the modified silicon micropowder within the range described in the present invention has better heat resistance.

[0114] 2. Compared with Examples 1-3, the flame retardancy and heat resistance of the product obtained in Comparative Example 2 are both reduced, indicating that the copper clad laminate prepared by adding the modified aluminum hydroxide in the range described in the present invention has better flame retardancy and heat resistance.

[0115] 3. Compared with Examples 1-3, the flame retardancy of the product obtained in Comparative Example 3 is reduced, indicating that the modified aluminum hydroxide prepared by the present invention has better flame retardancy than the unmodified aluminum hydroxide.

[0116] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include," "comprise," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0117] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A process for preparing an environmentally friendly and reliable halogen-free copper clad laminate, characterized by: The steps include: Step S1: uniformly mix the organic solvent, curing agent, and accelerator, heat to 20-40° C., stir for 50-60 minutes, add phosphorus-containing epoxy resin, phenolic epoxy resin, isocyanate-modified epoxy resin, benzoxazine resin, phosphorus-containing phenolic resin, and tetrafunctional epoxy resin, stir for 50-60 minutes, then add modified silica powder and modified aluminum hydroxide, stir uniformly, shear at a shear rate of 1000-5000 rad / min for 40-60 minutes, and emulsify for 130-150 minutes to prepare an adhesive for electronic glass fiber cloth; Step S2: uniformly coating the electronic glass fiber cloth with glue on the surface of the electronic glass fiber cloth, and baking at 215-225° C. for 90-100 seconds to obtain a prepreg; Step S3: stacking 4-8 prepregs to obtain a composite sheet, covering the upper and lower surfaces of the composite sheet with a copper foil, and performing hot pressing and cold pressing to obtain a halogen-free copper clad laminate; In step S1, the adhesive for electronic glass fiber cloth includes the following weight percentages: 10-15wt% organic solvent, 1.2-3.4wt% curing agent, 0.281-0.321wt% accelerator, 32-34wt% phosphorus-containing epoxy resin, 2-4wt% phenolic epoxy resin, 8-10wt% isocyanate-modified epoxy resin, 9-11wt% benzoxazine resin, 12-14wt% phosphorus-containing phenolic resin, 0.1-0.3wt% tetrafunctional epoxy resin, 8-12wt% modified silica powder, and 5-9wt% modified aluminum hydroxide; The preparation process of the modified silicon micropowder is as follows: Step (1): mixing silicon micropowder, sodium hydroxide solution and propylene glycol uniformly, ultrasonically treating for 1-3 hours, washing and filtering, and drying at 100-120° C. for 2-3 hours to obtain surface-activated silicon micropowder; Step (2): adding the surface-activated silicon micropowder to a mixed solution of ethanol and deionized water, ultrasonically dispersing for 30-50 minutes, then adding 3-glycidyloxypropyltrimethoxysilane and (aminoethylaminomethyl)phenethyltrimethoxysilane and mixing evenly, stirring in a 70-80°C water bath for 1-2 hours, cooling to room temperature, washing, filtering, and drying at 80-100°C for 12-24 hours to obtain pretreated silicon micropowder; Step (3): Under nitrogen protection, the pretreated silicon micropowder and N-(hydroxymethyl) acrylamide are mixed evenly, deionized water is added and mixed evenly, cerium nitrate ammonium is added dropwise for 1-2 hours, the temperature is raised to 30-40°C, the reaction is carried out for 2-4 hours, the mixture is filtered, washed, and dried at 80-100°C for 12-24 hours to obtain modified silicon micropowder; The preparation process of the modified aluminum hydroxide is as follows: Step a: Under nitrogen protection, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and dimethylamide are mixed evenly, (4-vinylphenyl)trimethoxysilane is added and mixed evenly, and the mixture is heated to 60-70° C., and azobisisobutyronitrile is added dropwise over 1-2 hours. The mixture is then heated to 75-85° C. and reacted for 8-10 hours. The mixture is cooled to room temperature, washed, filtered, and dried to obtain DOPO-based siloxane. Step b: Aluminum hydroxide and deionized water were mixed evenly, concentrated hydrochloric acid was slowly added dropwise to adjust the pH to 4.8-5.3, the mixture was heated to 60-70°C, a mixture of DOPO-based siloxane and anhydrous ethanol was added dropwise over 1-2 hours, and the mixture was reacted for 10-12 hours. After washing, filtration, and drying, substance A was obtained; Step c: Mix substance A, anhydrous ethanol and deionized water evenly, add ethyl orthosilicate dropwise for 1-2 hours, adjust the pH to 9-10 with ammonia water, heat to 40-50°C, react for 3-4 hours, cool to room temperature, centrifuge, wash and dry to obtain modified aluminum hydroxide.

2. The process for preparing an environmentally friendly and reliable halogen-free copper clad laminate according to claim 1, wherein: The organic solvent consists of butanone and dimethylformamide in a mass ratio of 1:(1-2).

3. The process for preparing an environmentally friendly and reliable halogen-free copper clad laminate according to claim 1, wherein: The curing agent is composed of a dicyandiamide curing agent and an NL-1 phenolic curing agent in a mass ratio of 1: (6.0-7.5).

4. The process for preparing an environmentally friendly and reliable halogen-free copper clad laminate according to claim 1, wherein: The accelerator is composed of 2-methylimidazole and 4,4'-diaminodiphenyl sulfone in a mass ratio of 1:(280-320).

5. The process for preparing an environmentally friendly and reliable halogen-free copper clad laminate according to claim 1, wherein: The hot pressing and cold pressing process conditions in step S3 are: hot pressing temperature 230-240° C., hot pressing pressure 2-3 MPa, hot pressing vacuum 15-20 Torr, hot pressing time 150-180 min; cold pressing temperature 20-25° C., cold pressing pressure 1-2 MPa, cold pressing time 60-80 min.

6. An environmentally friendly and reliable halogen-free copper clad laminate prepared according to the preparation process according to any one of claims 1 to 5.

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