Preparation method of CEM-1 copper-clad plate with high thermal reliability and high flexibility

Abstract

The application relates to a preparation method of a high-thermal-reliability high-flexibility CEM-1 copper-clad plate, and belongs to the field of copper-clad plate preparation methods. The bleached wood pulp paper adopts a twice-gluing process, the first gluing liquid adopts a tung oil modified water-soluble phenolic resin, the resin itself contains 30% water, can effectively open the paper fibers of the bleached wood pulp paper, is beneficial to full impregnation of the resin, guarantees the flexibility, and improves the moisture resistance of the plate; the E-51 base epoxy resin is used to replace the traditional brominated epoxy resin in the second gluing liquid, the resin has a small molecular weight, is beneficial to impregnation of the paper fibers, and a small amount of TBBA, a nitrogen-containing flame retardant, a phosphorus-containing flame retardant and a small amount of diantimony trioxide are added, the phosphorus-nitrogen synergistic effect cooperates with the bromine-antimony synergistic effect, and the flame retardation effect of the plate is guaranteed.

Description

Technical Field

[0001] This invention belongs to the technical field of copper clad laminate manufacturing, specifically relating to a method for preparing CEM-1 copper clad laminate. Background Technology

[0002] Due to its cost and processing advantages, CEM-1 is widely used in consumer electronics products with low performance requirements, such as control modules for home appliances like washing machines and air conditioners, toy remote controls, and LED lighting driver boards. With the increasing popularity of smart homes and low-cost IoT devices, this demand will continue to grow. However, during PCB manufacturing, CEM-1 boards are prone to warping after heating and rebounding after leveling. With increasing automation, this poor performance not only affects production efficiency but can also lead to product scrap. Furthermore, with rising soldering temperatures (currently reaching 255℃), the problem of traditional CEM-1 boards easily exploding during reflow soldering is becoming increasingly prominent. Therefore, improving the flexibility and thermal reliability of CEM-1 boards to meet customers' high-temperature reflow soldering requirements is a crucial aspect of CEM-1 copper clad laminate technology development. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and to provide a method for preparing a high-thermal-reliability and high-flexibility CEM-1 copper-clad laminate. The manufacturing method of this copper-clad laminate is as follows: the core material adopts a two-coating process. The first coating uses a tung oil-modified water-soluble phenolic resin, which contains 30% water, effectively opening the paper fibers of bleached wood pulp paper and facilitating full resin impregnation, thus ensuring flexibility and improving the board's moisture resistance. In the second coating, E-51 base epoxy resin replaces the traditional brominated epoxy resin. This resin has a small molecular weight, which facilitates the impregnation of paper fibers. TBBA, nitrogen-containing flame retardants, phosphorus-containing flame retardants, and a small amount of antimony trioxide are added. Through the synergistic effect of phosphorus and nitrogen combined with the synergistic effect of bromine and antimony, the flame-retardant effect of the board is guaranteed.

[0004] The technical solution adopted in this invention is as follows: a method for preparing a high thermal reliability and high flexibility CEM-1 copper clad laminate, the steps of which are as follows: S1. Preparation of adhesive solution for electronic fiberglass cloth: Prepare 70-80 parts by weight of brominated epoxy resin, 1.5-2.5 parts by weight of dicyandiamide, 0.05-0.1 parts by weight of 2-methylimidazole, 5-10 parts by weight of composite silica powder, and 15-20 parts by weight of solvent, mix and stir evenly. S2. Preparation of first-stage adhesive for bleached wood pulp paper: Prepare 90-96 parts by weight of tung oil-modified water-soluble phenolic resin, 0.05-0.15 parts by weight of 2-methylimidazole, and 4-8 parts by weight of solvent, mix and stir evenly; S3. Preparation of the second-coat adhesive for bleached wood pulp paper: Prepare 25-35 parts by weight of bisphenol A epoxy resin (E-51), 12-18 parts of tetrabromobisphenol A, 4-8 parts of linear phenolic resin (PN), 9-14 parts of tung oil-modified phenolic resin, 4-8 parts of phosphate ester, 2-6 parts of nitrogen-containing flame retardant, 2-6 parts of aluminum hydroxide, 1-5 parts of antimony trioxide, 0.05-0.15 parts of 2-methylimidazole, and 20-30 parts of solvent, mix and stir evenly; S4. The adhesive solution obtained in step S1 is evenly coated on both sides of the electronic fiberglass cloth and baked at 150-200℃ for 90-120s, with the adhesive content controlled at 42±2% and the flowability at 12-18%, to obtain a semi-cured film for the fabric. S5. The adhesive solution obtained in step S2 is evenly coated on both sides of bleached wood pulp paper and baked at 150-200℃ for 160-180s, controlling the adhesive content to 14±2% and the volatile matter to <5%, to obtain a pre-cured film. S6. The adhesive solution obtained in step S3 is uniformly coated on both sides of the semi-cured sheet obtained in step (5), and baked at 150-170℃ for 160-180s, controlling the adhesive content to be 53±2% and the flowability to be 4-6%, to obtain the core material semi-cured film. S7. Take several core material prepreg sheets obtained in step S6 and stack them together. Stack one fabric prepreg sheet obtained in step S4 on each of the top and bottom sides. Then cover one 1 oz or 2 oz electrolytic copper foil on one or both sides. Press the foil under a surface pressure of 3.5-4.5 MPa and a temperature of 165-175℃ for 90-120 minutes. After cooling, the CEM-1 copper clad laminate is obtained.

[0005] Preferably, the brominated epoxy resin described in step S1 has a bromine content of 19-21% by weight and an epoxy equivalent of 417-455 g / eq.

[0006] Preferably, the tung oil-modified water-soluble phenolic resin described in step S2 has a solid content of 30%, a water content of 30%, and a gelation time of 160-200s / 160℃*0.8g.

[0007] Preferably, the bisphenol A epoxy resin in step S3 has a solid content of 100% and an epoxy equivalent of 184-194 g / eq; the linear phenolic resin has a hydroxyl equivalent of 105-110 g / OH and a softening point of 96-101℃; the tung oil-modified phenolic resin has ≤10% free phenol and a gelation time of 160-200 s / 150℃*0.8 g.

[0008] Preferably, the phosphate ester mentioned in step S3 is one or a mixture of two or more of triphenyl phosphate, bisphenol A-bis(diphenyl phosphate), and resorcinol-bis(diphenyl phosphate).

[0009] Preferably, the nitrogen-containing flame retardant in step S3 is one or a mixture of two or more of melamine cyanurate, ammonium polyphosphate, and melamine polyphosphate.

[0010] Preferably, the solvent mentioned in steps S1 and S2 is one or any mixture of dimethylformamide, acetone, butanone, methanol, ethylene glycol monomethyl ether, and propylene glycol monomethyl ether.

[0011] Preferably, in steps S4 and S5, the basis weight of the electronic fiberglass cloth is 210±4 g / m³. 2 The basis weight of bleached wood pulp paper is 135±3 g / m³. 2 .

[0012] Compared with existing technologies, the advantages of this invention are as follows: This invention uses two adhesive solutions, in which the second adhesive solution uses bisphenol A epoxy resin (E-51) as the main resin, tetrabromobisphenol A (TBBA) and linear phenolic resin (PN) as curing agents, and tung oil-modified phenolic resin as a toughening agent. A certain proportion of phosphate ester, nitrogen-containing flame retardant, and a small amount of antimony trioxide are added, utilizing the synergistic effects of phosphorus and nitrogen and bromine and antimony to ensure the flame retardancy of the board. The CEM-1 copper-clad laminate prepared by this invention has good heat resistance, good flexibility, easy leveling, and excellent comprehensive performance, meeting the requirements of high-demand PCB applications. Detailed Implementation

[0013] The present invention will be further described in detail below with reference to the embodiments. The embodiments are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention. Example 1

[0014] A method for preparing a high thermal reliability and high flexibility CEM-1 copper clad laminate, comprising the following steps: (1) Preparation of adhesive solution for electronic fiberglass cloth: The adhesive for electronic fiberglass cloth, by weight percentage, comprises: 77% solvent-based brominated epoxy resin (80% solid content, 20% bromine content), 1.7% dicyandiamide, 0.05% 2-methylimidazole, 7.3% composite silica powder (purchased from Suzhou Jinyi New Material Technology Co., Ltd., material code JP.092.26, model M20) and 13.8% dimethylformamide; a. Add the solvents dimethylformamide and dicyandiamide to the stirred tank, start stirring to dissolve them completely, control the temperature inside the tank at 33℃, and stir for 60 minutes; b. Continue to add solvent-based brominated epoxy resin, dissolved 2-methylimidazole, and composite silica powder to the reactor, and stir continuously for 90 minutes to mix them evenly. Then turn on high-efficiency shearing and emulsify for 2.5 hours to obtain the adhesive solution for electronic fiberglass cloth.

[0015] The final adhesive solution has a solid content of 70%, a viscosity of 35s in the fourth cup, and a gelation time of 225s / 171℃*0.4g.

[0016] Preparation of first-stage sizing solution for bleached wood pulp paper: The first-stage adhesive for bleached wood pulp paper, by weight percentage, comprises: 94 parts of tung oil-modified water-soluble phenolic resin, 0.1 parts of 2-methylimidazole, and 6 parts of solvent, mixed and stirred evenly; the final adhesive has a solid content of 28% and a gelation time of 180s / 160℃*0.8g.

[0017] Second sizing solution for preparing bleached wood pulp paper: The second-coat adhesive for bleached wood pulp paper, by weight percentage, comprises: 29 parts bisphenol A epoxy resin, 15 parts tetrabromobisphenol A, 5 parts linear phenolic resin, 11 parts tung oil-modified phenolic resin, 5 parts phosphate ester, 3.5 parts nitrogen-containing flame retardant, 3.5 parts aluminum hydroxide, 2.5 parts antimony trioxide, 0.07 parts 2-methylimidazole, and 24 parts solvent (methanol), mixed and stirred evenly. a. Add bisphenol A epoxy resin, tetrabromobisphenol A, linear phenolic resin, methanol and dissolved 2-methylimidazole to a stirred tank, start stirring to dissolve them completely, control the temperature inside the tank at 28℃, and stir for 90 minutes. b. Continue to add tung oil-modified phenolic resin, resorcinol-bis(diphenyl phosphate), melamine cyanurate, aluminum hydroxide and antimony trioxide to the kettle, and stir continuously for 120 minutes to mix evenly. Then turn on high-efficiency shearing and emulsify for 3 hours to obtain the adhesive solution for electronic fiberglass cloth.

[0018] The final adhesive solution has a solid content of 71%, a viscosity of 18s in the fourth cup, and a curing time of 260s / 171℃*0.4g.

[0019] (4) Preparation of semi-cured sheets a. The electronic fiberglass cloth is impregnated in a vertical gluing machine, and the electronic fiberglass cloth is evenly coated with glue on the surface of the fiberglass cloth. After baking in an oven at 170℃, the glue content of the semi-cured sheet is controlled at 42.5% and the flowability is 14.1%, thus obtaining the fiberglass cloth semi-cured sheet. b. Bleached wood pulp paper undergoes one and two dips in a horizontal gluing machine, with the glue solution evenly coated on the surface of the wood pulp paper. After baking in an oven at 200℃, the first-stage semi-cured sheet has a glue content of 14.9% and volatile matter of 3.7%, while the second-stage semi-cured sheet has a glue content of 52.2% and a flowability of 5.3%, thus producing wood pulp paper semi-cured sheets.

[0020] (5) Preparation of CEM-1 copper clad laminate Six wood pulp paper prepregs are added between two fiberglass cloth prepregs, and then a 1 ounce electrolytic copper foil is applied to one side. The mixture is pressed together at 4.0 MPa surface pressure and 175°C for 120 minutes. After cooling, the CEM-1 copper clad laminate is obtained.

[0021] The performance of the obtained copper-clad laminate was tested, and the test results are shown in Table 1. Example 2

[0022] A method for preparing a high thermal reliability and high flexibility CEM-1 copper clad laminate, comprising the following steps: (1) Preparation of adhesive solution for electronic fiberglass cloth: The adhesive for electronic fiberglass cloth, by weight percentage, comprises: 75% solvent-based brominated epoxy resin (80% solid content and 20% bromine content), 1.5% dicyandiamide, 0.04% 2-methylimidazole, 9.3% composite silica powder, and 14% dimethylformamide. a. Add the solvents dimethylformamide and dicyandiamide to the stirred tank, start stirring to dissolve them completely, control the temperature inside the tank at 33℃, and stir for 60 minutes; b. Continue to add solvent-based brominated epoxy resin, dissolved 2-methylimidazole, and composite silica powder to the reactor, and stir continuously for 90 minutes to mix them evenly. Then turn on high-efficiency shearing and emulsify for 2.5 hours to obtain the adhesive solution for electronic fiberglass cloth.

[0023] The final adhesive solution has a solid content of 70%, a viscosity of 33s in the fourth cup, and a gelation time of 230s / 171℃*0.4g.

[0024] Preparation of first-stage sizing solution for bleached wood pulp paper: The first-stage adhesive for bleached wood pulp paper, by weight percentage, comprises: 92 parts of tung oil-modified water-soluble phenolic resin, 0.1 parts of 2-methylimidazole, and 8 parts of solvent, mixed and stirred evenly; the final adhesive has a solid content of 28% and a gelation time of 185 s / 160℃*0.8 g.

[0025] Second sizing solution for preparing bleached wood pulp paper: The second-coat adhesive for bleached wood pulp paper, by weight percentage, comprises: 28 parts bisphenol A epoxy resin, 14.5 parts tetrabromobisphenol A, 6 parts linear phenolic resin, 10 parts tung oil-modified phenolic resin, 4 parts phosphate ester, 4 parts nitrogen-containing flame retardant, 4 parts aluminum hydroxide, 2.5 parts antimony trioxide, 0.07 parts 2-methylimidazole, and 27 parts solvent, mixed and stirred evenly. a. Add bisphenol A epoxy resin, tetrabromobisphenol A, linear phenolic resin, methanol and dissolved 2-methylimidazole to a stirred tank, start stirring to dissolve them completely, control the temperature inside the tank at 28℃, and stir for 90 minutes. b. Continue to add tung oil-modified phenolic resin, resorcinol-bis(di(2,6-dimethylphenyl)phosphate), melamine cyanurate, aluminum hydroxide and antimony trioxide to the reactor, and stir continuously for 120 minutes to mix evenly. Then turn on high-efficiency shearing and emulsify for 3 hours to obtain the adhesive solution for electronic fiberglass cloth.

[0026] The final adhesive solution has a solid content of 71%, a viscosity of 18s in the fourth cup, and a curing time of 240s / 171℃*0.4g.

[0027] (4) Preparation of semi-cured sheets a. The electronic fiberglass cloth is impregnated in a vertical gluing machine, and the electronic fiberglass cloth is evenly coated with glue on the surface of the fiberglass cloth. After baking in an oven at 165℃, the glue content of the semi-cured sheet is controlled at 42.5% and the flowability is 14.1%, thus obtaining the fiberglass cloth semi-cured sheet. b. Bleached wood pulp paper undergoes one and two dips in a horizontal gluing machine, with the glue solution evenly coated on the surface of the wood pulp paper. After baking in an oven at 180°C, the first-stage semi-cured sheet has a glue content of 14.9% and volatile matter of 3.7%, while the second-stage semi-cured sheet has a glue content of 52.2% and a flowability of 5.3%, thus producing wood pulp paper semi-cured sheets.

[0028] (5) Preparation of CEM-1 copper clad laminate Six wood pulp paper prepregs are added between two fiberglass cloth prepregs, and then a 1 ounce electrolytic copper foil is applied to one side. The mixture is pressed together at 4.0 MPa and 175°C for 120 minutes. After cooling, the CEM-1 copper clad laminate is obtained.

[0029] The performance of the obtained copper-clad laminate was tested, and the test results are shown in Table 1.

[0030] Table 1 Performance of Copper Clad Laminates

[0031] As can be seen from Table 1, the CEM-1 board produced by this invention has excellent comprehensive performance and can meet the usage requirements of demanding PCB customers.

[0032] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a high thermal reliability and high flexibility CEM-1 copper clad laminate, characterized in that: The steps are as follows: S1. Preparation of adhesive solution for electronic fiberglass cloth: Prepare 70-80 parts by weight of brominated epoxy resin, 1.5-2.5 parts by weight of dicyandiamide, 0.05-0.1 parts by weight of 2-methylimidazole, 5-10 parts by weight of composite silica powder, and 15-20 parts by weight of solvent, mix and stir evenly. S2. Preparation of first-stage adhesive for bleached wood pulp paper: Prepare 90-96 parts by weight of tung oil-modified water-soluble phenolic resin, 0.05-0.15 parts by weight of 2-methylimidazole, and 4-8 parts by weight of solvent, mix and stir evenly; S3. Preparation of the second-coat adhesive for bleached wood pulp paper: Prepare 25-35 parts by weight of bisphenol A epoxy resin (E-51), 12-18 parts of tetrabromobisphenol A, 4-8 parts of linear phenolic resin (PN), 9-14 parts of tung oil-modified phenolic resin, 4-8 parts of phosphate ester, 2-6 parts of nitrogen-containing flame retardant, 2-6 parts of aluminum hydroxide, 1-5 parts of antimony trioxide, 0.05-0.15 parts of 2-methylimidazole, and 20-30 parts of solvent, mix and stir evenly; S4. The adhesive solution obtained in step S1 is evenly coated on both sides of the electronic fiberglass cloth and baked at 150-200℃ for 90-120s, with the adhesive content controlled at 42±2% and the flowability at 12-18%, to obtain a semi-cured film for the fabric. S5. The adhesive solution obtained in step S2 is evenly coated on both sides of bleached wood pulp paper and baked at 150-200℃ for 160-180s, controlling the adhesive content to 14±2% and the volatile matter to <5%, to obtain a pre-cured film. S6. The adhesive solution obtained in step S3 is uniformly coated on both sides of the semi-cured sheet obtained in step (5), and baked at 150-200℃ for 160-180s, controlling the adhesive content to be 53±2% and the flowability to be 4-6%, to obtain the core material semi-cured film. S7. Take several core material prepreg sheets obtained in step S6 and stack them together. Stack one fabric prepreg sheet obtained in step S4 on each of the top and bottom sides. Then cover one 1 oz or 2 oz electrolytic copper foil on one or both sides. Press the foil under a surface pressure of 3.5-4.5 MPa and a temperature of 165-175℃ for 90-120 minutes. After cooling, the CEM-1 copper clad laminate is obtained.

2. The method according to claim 1, characterized in that, The brominated epoxy resin mentioned in step S1 has a bromine content of 19-21% by weight and an epoxy equivalent of 417-455 g / eq. The composite silica powder was purchased from Suzhou Jinyi New Material Technology Co., Ltd., with material code JP.092.26 and model M20.

3. The method according to claim 1, characterized in that, The tung oil-modified water-soluble phenolic resin described in step S2 has a solid content of 30%, a water content of 30%, and a gelation time of 160-200s / 160℃*0.8g.

4. The method according to claim 1, characterized in that, The bisphenol A epoxy resin mentioned in step S3 has a solid content of 100% and an epoxy equivalent of 184-194 g / eq; the linear phenolic resin has a hydroxyl equivalent of 105-110 g / OH and a softening point of 96-101℃; the tung oil modified phenolic resin has ≤10% free phenol and a gelation time of 160-200 s / 150℃*0.8 g.

5. The method according to claim 1, characterized in that, The phosphate ester mentioned in step S3 is one or a mixture of two or more of the following: triphenyl phosphate, bisphenol A-bis(diphenyl phosphate), and resorcinol-bis(diphenyl phosphate).

6. The method according to claim 1, characterized in that, The nitrogen-containing flame retardant mentioned in step S3 is one or a mixture of two or more of melamine cyanurate, ammonium polyphosphate, and melamine polyphosphate.

7. The method according to claim 1, characterized in that, The solvents mentioned in steps S1-S3 are one or any mixture of dimethylformamide, acetone, butanone, methanol, ethylene glycol monomethyl ether, and propylene glycol monomethyl ether.

8. The method according to claim 1, characterized in that, In steps S4 and S5, the basis weight of the electronic fiberglass cloth is 210±4 g / m. 2 The basis weight of bleached wood pulp paper is 135±3 g / m³. 2 .

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