A low-solvent-usage t g140 lead-free ccl material and its preparation process

Abstract

The application discloses a kind of Tg140 lead-free copper-clad plate materials with low solvent usage and preparation process thereof, and belongs to the technical field of copper-clad plate.The process of the present application uses brominated epoxy resin, polyamide acid modified epoxy resin, bismaleimide modified epoxy resin, liquid crystal modified epoxy resin, cyanate ester resin, phenolic resin as raw material, cooperates wetting agent, organic filler and the like to prepare resin glue solution, and after impregnating glass fiber cloth, a bonding sheet is obtained, and finally combined with copper foil to press to obtain copper-clad plate.The present application not only can significantly reduce the amount of organic solvent required for preparing resin glue solution, but also can ensure the excellent mechanical properties of copper-clad plate, providing a new way for preparing green and environmentally friendly, high peel strength, high bending strength and high performance copper-clad plate.

Description

Technical Field

[0001] The invention belongs to the technical field of copper clad laminates, and particularly relates to a Tg140 lead-free copper clad laminate material with low solvent usage and a preparation process thereof. Background Art

[0002] With the rapid development of electronic appliances, people have put forward more and more requirements for printed circuit boards, involving requirements in many aspects such as compactness, multi-function, lead-free, halogen-free and green production, which undoubtedly puts higher requirements on the production process of copper clad laminates.

[0003] Copper-clad laminate (CCL), short for copper-clad laminate, is the core material for printed circuit boards (PCBs), providing electrical conductivity, insulation, and support. CCL is made from a reinforcing material such as wood pulp paper or fiberglass cloth, impregnated with a resin adhesive to create a bonding sheet. Several bonding sheets are assembled, coated with copper foil on one or both sides, and then cured by heat pressing to create a sheet-like material. As resin adhesive is crucial for many of CCL's performance indicators, its raw material selection and preparation process are crucial in CCL production.

[0004] Resin glue is generally a "glue" made by mixing different resins or resin mixtures with fillers and then adding organic solvents. Resin glue directly affects the various properties of the bonding sheets. To adjust the dispersion and viscosity of different resin compositions and fillers, the industry often uses a mixture of multiple organic solvents as the regulating solvent for the resin mixture, and the amount used is huge. The use of large amounts of solvent increases the amount of solvent volatilization in the later stage, causing significant environmental risks and increasing recycling costs. Therefore, how to effectively reduce the amount of solvent used in the process while ensuring the mechanical properties of the copper clad laminate has become a pressing issue to be solved in green production. Summary of the Invention

[0005] In view of the background technology, the present invention aims to provide a Tg140 lead-free copper-clad laminate material with low solvent usage and a preparation process thereof. The present invention utilizes a curing system composed of brominated epoxy resin, polyamic acid-modified epoxy resin, bismaleimide-modified epoxy resin, liquid crystal-modified epoxy resin, cyanate ester resin, and phenolic resin, combined with a wetting agent and organic filler. This significantly reduces the amount of resin glue solvent used while maintaining the mechanical properties of the copper-clad laminate, resulting in excellent market competitiveness.

[0006] To achieve the above object, the present invention specifically adopts the following technical solutions:

[0007] The present invention provides a preparation process of a Tg140 lead-free copper clad laminate material with low solvent usage, comprising the following steps:

[0008] Step 1: Adding an epoxy resin mixture and a wetting agent to an inorganic filler, mixing, and high-speed shearing at 30-50° C., then adding an organic filler, a cyanate resin, and a phenolic resin to the resulting mixture, mixing evenly, and adjusting the viscosity with a solvent to obtain a resin glue; the epoxy resin mixture comprises a brominated epoxy resin, a polyamic acid-modified epoxy resin, a bismaleimide-modified epoxy resin, and a liquid crystal-modified epoxy resin;

[0009] Step 2: impregnating the glass fiber cloth with the resin glue obtained in step 1, and then baking it at 180-210° C. to obtain a bonding sheet;

[0010] Step 3: Assemble several adhesive sheets obtained in step 2, coat one or both sides with copper foil, and then press them together to form a Tg140 lead-free copper clad laminate material.

[0011] Preferably, the raw materials in step 1 are calculated by weight as follows: 90-110 parts of epoxy resin mixture, 15-25 parts of cyanate resin, 45-70 parts of phenolic resin, 15-20 parts of inorganic filler, 4-6 parts of organic filler, 2-5 parts of wetting agent, and sufficient solvent.

[0012] Preferably, the epoxy resin mixture consists of brominated epoxy resin, polyamic acid modified epoxy resin, bismaleimide modified epoxy resin and liquid crystal modified epoxy resin in a mass ratio of (5-8):(1-2):(1-2):1.

[0013] Preferably, the preparation method of the polyamic acid modified epoxy resin is: polyamic acid and E51 type epoxy resin are mixed in a mass ratio of 1:3, a catalyst and a solvent are added, the temperature is raised to 80-90°C, and the mixture is stirred at a constant temperature for 3-5 hours. After removing impurities, the polyamic acid modified epoxy resin is obtained.

[0014] Preferably, the preparation method of the bismaleimide-modified epoxy resin is as follows: bismaleimide and E51 epoxy resin are mixed in a mass ratio of 1:4, a catalyst and a solvent are added, the temperature is raised to 100-110° C., and the mixture is stirred at a constant temperature for 5-7 h. After removing impurities, the bismaleimide-modified epoxy resin is obtained.

[0015] Preferably, the preparation method of the liquid crystal modified epoxy resin is: taking a thermotropic liquid crystal polymer and blending it with 2-3 times the mass of PSU, heating the resulting mixture to melt, then adding it to 15-25 times the mass of E44 type epoxy resin heated to the same temperature in advance, mixing at a constant temperature, cooling and adding a curing agent and a catalyst to obtain a liquid crystal modified epoxy resin.

[0016] Preferably, the inorganic filler is at least one of aluminum hydroxide, white carbon black, silicon carbide, titanium oxide, and kaolin; and the organic filler is organic tin acetate.

[0017] Preferably, the wetting agent is polyethylene glycol octylphenyl ether.

[0018] Tg is a key indicator for measuring heat resistance, which indirectly affects the mechanical, electrical, chemical and other properties of the copper clad laminate. The process of the present invention uses a variety of modified resins as raw materials to prepare a Tg140 lead-free copper clad laminate with low solvent usage. The present invention uses brominated epoxy resin as the main resin. Brominated epoxy resin has excellent heat resistance, electrical insulation and adhesion. The main curing system constructed with phenolic resin can maintain the basic viscosity of the glue and the basic strength and heat resistance of the bonding sheet. In addition, the process of the present invention uses polyamic acid and bismaleimide to modify E51 type epoxy resin respectively. Polyamic acid can form an ester-like structure with the epoxy group when modifying the epoxy resin. Its own activity can also be amidated to form a long chain with bismaleimide, so that the curing system shows high bonding shear strength and heat resistance. The combination of the two can not only promote compatibility and significantly improve the bonding strength of the glue at high temperature, but also enhance the peeling performance of the system. Thermotropic liquid crystal polymers contain liquid crystal units. Adding modified epoxy resins to the above-mentioned system can further compensate for matrix brittleness and enhance overall mechanical properties without affecting mechanical properties. Cyanate ester resins have excellent high-temperature mechanical properties, flexural strength, dimensional stability, and stable dielectric properties. The present invention also incorporates a special wetting agent and an inorganic / organic composite filler. Polyethylene glycol octylphenyl ether and organotin acetate promote dispersibility between the inorganic filler and the mixed resin, further enhancing compatibility between the resin systems. Ultimately, this not only effectively reduces the amount of organic solvent used in the resin glue, but also imparts excellent mechanical properties to the cured glue.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention overcomes the defect that the resin glue system prepared by conventional epoxy resin and inorganic filler cannot meet the requirements of high performance and green production. A variety of modified epoxy resins are used in conjunction with cyanate resin and phenolic resin to construct a main curing system, and a wetting agent and an organic filler are used. At the same time, the amount of raw materials and the preparation process are optimized. This not only can significantly reduce the amount of organic solvent required for preparing the resin glue, but also can ensure the excellent mechanical properties of the copper clad laminate, providing a new way to prepare green and environmentally friendly high-performance copper clad laminates with high peel strength and high bending strength. DETAILED DESCRIPTION

[0021] To make the objects, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be described clearly and completely below in conjunction with the examples. Where specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. Where the manufacturer of the reagents or instruments is not specified, all are commercially available conventional products.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] Example 1

[0024] A preparation process of Tg140 lead-free copper clad laminate material:

[0025] 1. Add maleic anhydride to a DMF solution of 4,4'-diaminodiphenyl ether in several portions and mix thoroughly in a 60°C water bath to obtain polyamic acid. Mix 100 parts by weight of polyamic acid with 300 parts by weight of E51 epoxy resin, add 1.2 parts by weight of triphenylphosphine and an appropriate amount of DMF, heat to 85°C, stir at constant temperature for 4 hours, and remove impurities in vacuo to obtain a polyamic acid-modified epoxy resin. Mix 100 parts by weight of bismaleimide with 400 parts by weight of E51 epoxy resin, add 0.5 parts by weight of dibutyltin dilaurate and an appropriate amount of DMA, heat to 105°C, stir at constant temperature for 5.5 hours, and remove impurities in vacuo to obtain a bismaleimide-modified epoxy resin. 1.5 parts by weight of Xydar II (Amoco, USA) and 3.5 parts by weight of PSU (GF-1006) were blended and heated to melt as a modifier and kept at a constant temperature. 100 parts by weight of E44 epoxy resin was heated to the same temperature and mixed with the modifier at a constant temperature for 30 minutes. The mixture was then cooled to 145°C and added with 3 parts by weight of 2-methylimidazole and 0.8 parts by weight of DMP-30. The mixture was reacted for 2 hours to obtain a liquid crystal modified epoxy resin.

[0026] 2. Weigh, by weight, 60 parts of brominated epoxy resin NPEB-400, 15 parts of the above-mentioned polyamic acid-modified epoxy resin, 15 parts of the above-mentioned bismaleimide-modified epoxy resin, 10 parts of the above-mentioned liquid crystal-modified epoxy resin, 20 parts of cyanate ester resin, 55 parts of phenolic resin 2123, 9 parts of aluminum hydroxide, 7 parts of white carbon black, 5 parts of organic tin acetate, and 3.5 parts of polyethylene glycol octylphenyl ether.

[0027] 3. Brominated epoxy resin NPEB-400, liquid crystal modified epoxy resin, polyamic acid modified epoxy resin, bismaleimide modified epoxy resin, and polyethylene glycol octylphenyl ether were added to aluminum hydroxide and white carbon black in sequence, and mixed. The mixture was sheared at 40°C at high speed. Organic tin acetate, cyanate resin, and phenolic resin 2123 were added to the obtained mixture and mixed evenly. A sufficient amount of a solvent mixture of propylene glycol methyl ether and butanone of equal mass was added to adjust the viscosity to 20 s (the final solvent amount was 55 parts) to obtain a resin glue. The obtained resin glue was used to coat glass fiber cloth (7628, 0.173 mm thick, 204.4 g / m2 per unit area). 2 ) for impregnation and baked at 195°C until the resin content reached 48% to obtain bonding sheets; 8 bonding sheets were stacked with 2 pieces of copper foil (1oz, the same below) and pressed into a copper clad laminate with a thickness of 1.6 mm.

[0028] Example 2

[0029] A preparation process of Tg140 lead-free copper clad laminate material:

[0030] 1. Add maleic anhydride to a DMF solution of 4,4'-diaminodiphenyl ether in several portions and mix thoroughly in a 60°C water bath to obtain polyamic acid. Mix 100 parts by weight of polyamic acid with 300 parts by weight of E51 epoxy resin, add 1.4 parts by weight of triphenylphosphine and an appropriate amount of DMF, heat to 85°C, stir at constant temperature for 3 hours, and remove impurities in a vacuum to obtain a polyamic acid-modified epoxy resin. Mix 100 parts by weight of bismaleimide with 400 parts by weight of E51 epoxy resin, add 0.6 parts by weight of dibutyltin dilaurate and an appropriate amount of DMA, heat to 105°C, stir at constant temperature for 5 hours, and remove impurities in a vacuum to obtain a bismaleimide-modified epoxy resin. 1.3 parts by weight of Xydar II (Amoco, USA) and 3.9 parts by weight of PSU (GF-1006) were blended, heated to melt as a modifier and maintained at a constant temperature. 100 parts by weight of E44 epoxy resin was heated to the same temperature and mixed with the modifier at a constant temperature for 30 minutes. The mixture was then cooled to 145°C and added with 3 parts by weight of 2-methylimidazole and 0.8 parts by weight of DMP-30. The mixture was reacted for 2 hours to obtain a liquid crystal modified epoxy resin.

[0031] 2. Weigh, by weight, 60 parts of brominated epoxy resin NPEB-400, 20 parts of the above-mentioned polyamic acid-modified epoxy resin, 20 parts of the above-mentioned bismaleimide-modified epoxy resin, 10 parts of the above-mentioned liquid crystal-modified epoxy resin, 15 parts of cyanate ester resin, 65 parts of phenolic resin 2123, 9 parts of aluminum hydroxide, 7 parts of white carbon black, 5 parts of organic tin acetate, and 3.5 parts of polyethylene glycol octylphenyl ether.

[0032] 3. Brominated epoxy resin NPEB-400, liquid crystal modified epoxy resin, polyamic acid modified epoxy resin, bismaleimide modified epoxy resin, and polyethylene glycol octylphenyl ether were added to aluminum hydroxide and white carbon black in sequence, and mixed. The mixture was sheared at 40°C at high speed. Organic tin acetate, cyanate resin, and phenolic resin 2123 were added to the mixture and mixed evenly. A sufficient amount of a solvent mixture of propylene glycol methyl ether and butanone of equal mass was added to adjust the viscosity to 20 s (the final solvent amount was 63 parts) to obtain a resin glue. The obtained resin glue was used to coat glass fiber cloth (7628, 0.173 mm thick, 204.4 g / m2 per unit area). 2 ) for impregnation and baked at 195°C until the resin content reached 48% to obtain an adhesive sheet; 8 adhesive sheets were stacked with 2 copper foils and pressed into a copper clad laminate with a thickness of 1.6 mm.

[0033] Example 3

[0034] A preparation process of Tg140 lead-free copper clad laminate material:

[0035] 1. Add maleic anhydride to a DMF solution of 4,4'-diaminodiphenyl ether in several portions and mix thoroughly in a 60°C water bath to obtain polyamic acid; mix 100 parts by weight of polyamic acid with 300 parts by weight of E51 epoxy resin, add 1 part by weight of triphenylphosphine and an appropriate amount of DMF, heat to 85°C, stir at constant temperature for 5 hours, and remove impurities in a vacuum to obtain a polyamic acid-modified epoxy resin. Mix 100 parts by weight of bismaleimide with 400 parts by weight of E51 epoxy resin, add 0.5 parts by weight of dibutyltin dilaurate and an appropriate amount of DMA, heat to 100°C, stir at constant temperature for 6.5 hours, and remove impurities in a vacuum to obtain a bismaleimide-modified epoxy resin. 1.8 parts by weight of Xydar II (Amoco, USA) and 3.6 parts by weight of PSU (GF-1006) were blended, heated to melt as a modifier and maintained at a constant temperature. 120 parts by weight of E44 epoxy resin was heated to the same temperature and mixed with the modifier at a constant temperature for 30 minutes. The mixture was then cooled to 145°C and added with 3 parts by weight of 2-methylimidazole and 0.8 parts by weight of DMP-30. The mixture was reacted for 2 hours to obtain a liquid crystal modified epoxy resin.

[0036] 2. Weigh by weight 72 parts of brominated epoxy resin NPEB-400, 12 parts of the above-mentioned polyamic acid modified epoxy resin, 12 parts of the above-mentioned bismaleimide modified epoxy resin, 12 parts of the above-mentioned liquid crystal modified epoxy resin, 25 parts of cyanate ester resin, 45 parts of phenolic resin 2123, 9 parts of aluminum hydroxide, 7 parts of white carbon black, 4 parts of organic tin acetate, and 4 parts of polyethylene glycol octylphenyl ether.

[0037] 3. Brominated epoxy resin NPEB-400, liquid crystal modified epoxy resin, polyamic acid modified epoxy resin, bismaleimide modified epoxy resin, and polyethylene glycol octylphenyl ether were added to aluminum hydroxide and white carbon black in sequence, and mixed. The mixture was sheared at 40°C at high speed. Organic tin acetate, cyanate resin, and phenolic resin 2123 were added to the obtained mixture and mixed evenly. A sufficient amount of a solvent mixture of propylene glycol methyl ether and butanone of equal mass was added to adjust the viscosity to 20 s (the final solvent amount was 58 parts) to obtain a resin glue. The obtained resin glue was used to coat glass fiber cloth (7628, 0.173 mm thick, 204.4 g / m2 per unit area). 2 ) for impregnation and baked at 195°C until the resin content reached 48% to obtain an adhesive sheet; 8 adhesive sheets were stacked with 2 copper foils and pressed into a copper clad laminate with a thickness of 1.6 mm.

[0038] Comparative Example 1

[0039] Refer to the step parameters of Example 1, except that no polyamic acid modified epoxy resin is added, that is:

[0040] The epoxy resin mixture used is composed of 70.6 parts of brominated epoxy resin NPEB-400, 17.6 parts of bismaleimide-modified epoxy resin of Example 1, and 11.8 parts of liquid crystal-modified epoxy resin of Example 1.

[0041] The amount of solvent used to adjust the viscosity of the resin glue to 20 s is 84 parts.

[0042] Comparative Example 2

[0043] Refer to the step parameters of Example 1, except that no liquid crystal modified epoxy resin is added, that is:

[0044] The epoxy resin mixture used is composed of 66.6 parts of brominated epoxy resin NPEB-400, 16.7 parts of polyamic acid modified epoxy resin of Example 1, and 16.7 parts of bismaleimide modified epoxy resin of Example 1.

[0045] The amount of solvent used to adjust the viscosity of the resin glue to 20 s was 77 parts.

[0046] Comparative Example 3

[0047] Refer to the step parameters of Example 1, except that no cyanate resin is added, that is:

[0048] The raw materials used are as follows: 60 parts of brominated epoxy resin NPEB-400, 15 parts of polyamic acid modified epoxy resin in Example 1, 15 parts of bismaleimide modified epoxy resin in Example 1, 10 parts of liquid crystal modified epoxy resin in Example 1, 20 parts of cyanate resin, 55 parts of phenolic resin 2123, 9 parts of aluminum hydroxide, 7 parts of white carbon black, 5 parts of organic tin acetate, and 3.5 parts of polyethylene glycol octylphenyl ether.

[0049] The amount of solvent used to adjust the viscosity of the resin glue to 20 s is 85 parts.

[0050] Comparative Example 4

[0051] Refer to the step parameters of Example 1, except that organotin acetate is not used as the filler, that is:

[0052] Only inorganic fillers are used - 12 parts aluminum hydroxide and 9 parts white carbon black.

[0053] The amount of solvent used to adjust the viscosity of the resin glue to 20 s is 84 parts.

[0054] Comparative Example 5

[0055] Refer to the step parameters of Example 1, except that the wetting agent polyethylene glycol octylphenyl ether is not used.

[0056] The amount of solvent used to adjust the viscosity of the resin glue to 20 s was 79 parts.

[0057] Test example

[0058] The samples prepared in Examples 1-3 and Comparative Examples 1-5 were subjected to performance testing (IPC-TM-650), and the results are shown in Table 1.

[0059] Table 1

[0060]

[0061] In summary, the glue system of the present invention can effectively reduce the solvent usage by 25%-35%, greatly reducing environmental risks and subsequent recycling costs of the process. At the same time, the prepared copper clad laminate has excellent peel strength, bending strength, etc., and excellent mechanical properties, meeting green production and people's various requirements for printed circuit boards.

[0062] The embodiments described above merely represent several preferred embodiments of the present invention. While the descriptions are relatively specific and detailed, they are not intended to limit the present invention. It should be noted that those skilled in the art will readily appreciate that the present invention is susceptible to various variations and modifications. Any modifications, equivalent substitutions, or improvements within the scope of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A preparation process for Tg140 lead-free copper clad laminate material with low solvent usage, characterized in that: The steps include: Step 1: Add epoxy resin mixture and wetting agent to inorganic filler and mix them, high-speed shear at 30-50°C, then add organic filler, cyanate resin and phenolic resin to the obtained mixture and mix them evenly, and adjust the viscosity with solvent to obtain resin glue; The raw materials are calculated by weight as follows: 90-110 parts of epoxy resin mixture, 15-25 parts of cyanate resin, 45-70 parts of phenolic resin, 15-20 parts of inorganic filler, 4-6 parts of organic filler, 2-5 parts of wetting agent, and sufficient solvent; the epoxy resin mixture is composed of brominated epoxy resin, polyamic acid modified epoxy resin, bismaleimide modified epoxy resin, and liquid crystal modified epoxy resin in a mass ratio of (5-8):(1-2):(1-2):1; the organic filler is organotin acetate, and the wetting agent is polyethylene glycol octylphenyl ether; Step 2: impregnating the glass fiber cloth with the resin glue obtained in step 1, and then baking it at 180-210° C. to obtain a bonding sheet; Step 3: Assemble several adhesive sheets obtained in step 2, coat one or both sides with copper foil, and then press them together to form a Tg140 lead-free copper clad laminate material.

2. The preparation process of Tg140 lead-free copper clad laminate material with low solvent usage according to claim 1, characterized in that: The preparation method of the polyamic acid modified epoxy resin is as follows: polyamic acid and E51 epoxy resin are mixed in a mass ratio of 1:3, a catalyst and a solvent are added, the temperature is raised to 80-90° C., constant temperature stirring is performed for 3-5 hours, and the polyamic acid modified epoxy resin is obtained after impurities are removed.

3. The preparation process of Tg140 lead-free copper clad laminate material with low solvent usage according to claim 1, characterized in that: The preparation method of the bismaleimide-modified epoxy resin is as follows: bismaleimide and E51 epoxy resin are mixed in a mass ratio of 1:4, a catalyst and a solvent are added, the temperature is raised to 100-110° C., constant temperature stirring is performed for 5-7 hours, and the bismaleimide-modified epoxy resin is obtained after impurities are removed.

4. The preparation process of Tg140 lead-free copper clad laminate material with low solvent usage according to claim 1, characterized in that: The preparation method of the liquid crystal modified epoxy resin comprises: mixing a thermotropic liquid crystal polymer with PSU (2-3 times its mass), heating and melting the obtained mixture, then adding it to E44 epoxy resin (15-25 times its mass) that has been heated to the same temperature in advance, mixing at a constant temperature, cooling, adding a curing agent and a catalyst, and obtaining the liquid crystal modified epoxy resin.

5. The preparation process of Tg140 lead-free copper clad laminate material with low solvent usage according to claim 1, characterized in that: The inorganic filler is at least one of aluminum hydroxide, white carbon black, silicon carbide, titanium oxide, and kaolin.

6. The Tg140 lead-free copper clad laminate material obtained by the preparation process according to any one of claims 1 to 5.

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