High heat-resistant biphenyl novolac epoxy resin, preparation method and application thereof

Abstract

The application discloses a high-heat-resistance biphenyl phenolic aldehyde type epoxy resin and a preparation method and application thereof. The preparation method comprises the following steps: mixing phenol-phenyloligophenyl type resin, epichlorohydrin, a cosolvent I, an etherification catalyst and 10-20% sodium hydroxide water solution to perform an etherification reaction, adding 45-50% sodium hydroxide solution under a negative pressure of-0.08 to-0.06 MPa to perform a ring closure reaction, and obtaining a crude biphenyl phenolic aldehyde type epoxy resin through post-treatment; dissolving the crude biphenyl phenolic aldehyde type epoxy resin in a cosolvent II, adding a phase transfer catalyst and 10-20% sodium hydroxide water solution to perform a refining reaction, and obtaining the high-heat-resistance biphenyl phenolic aldehyde type epoxy resin through post-treatment. The phenol-phenyloligophenyl type resin is etherified by using a quaternary ammonium salt and a low-concentration lye in cooperation, and the refining reaction is performed, so that the obtained biphenyl phenolic aldehyde type epoxy resin is high in yield and significantly low in organic chlorine and total chlorine.

Description

Technical Field

[0001] This invention belongs to the field of special epoxy resin technology, specifically relating to a high heat-resistant biphenyl phenolic epoxy resin, its preparation method, and its application. Background Technology

[0002] As electronic components evolve towards higher integration, miniaturization, and higher power density, increasingly stringent requirements are being placed on the performance of packaging materials. Traditional epoxy resins, such as o-cresolaldehyde epoxy (ECN) and bisphenol A epoxy resins, are finding it increasingly difficult to meet the demands of high-end semiconductor packaging (such as large-scale integrated circuits and high-brightness LEDs) and advanced printed circuit boards (such as high-frequency copper-clad laminates) in terms of heat resistance, low moisture absorption, and dielectric properties. Especially with the widespread adoption of lead-free solder reflow soldering processes, packages need to withstand higher soldering temperatures, requiring materials to possess higher glass transition temperatures (Tg), lower coefficients of thermal expansion, and excellent resistance to thermal decomposition to prevent warping and delamination failure.

[0003] Biphenyl phenolic epoxy resins, with their unique rigid biphenyl structure and phenolic skeleton, have become key materials for solving the aforementioned problems. Their cured products exhibit low melt viscosity, excellent processing fluidity, high bond strength, and outstanding flame retardancy. These resins can achieve the UL 94 V-0 flame retardancy standard without the addition of any halogen or phosphorus-based flame retardants, meeting environmental regulatory requirements. Furthermore, their rigid molecular structure endows the material with low moisture absorption and a low dielectric constant / loss factor, which is crucial for ensuring the integrity of high-frequency signal transmission and the long-term reliability of devices. Therefore, these resins are widely recognized as ideal substrates for semiconductor packaging (epoxy molding compounds, EMC), LED reflectors, and high-performance copper-clad laminate matrix resins.

[0004] Despite the superior performance of biphenyl phenolic epoxy resin, its preparation still faces numerous challenges using existing technologies. Firstly, there are issues with product purity and color. Resins synthesized via conventional routes often have a darker color (yellow or brownish-yellow) and high levels of residual hydrolyzable chlorine and total chlorine (typically exceeding 1500 ppm). This can severely impact luminous efficacy and color temperature in high-brightness white LED packaging and may lead to corrosion of metal circuits in microelectronic applications. Secondly, the introduction of the biphenyl structure worsens the homogeneity of the reaction system, reducing the efficiency of the etherification and epoxidation reactions between the phenolic resin intermediate and epichlorohydrin, increasing byproducts, and causing large fluctuations in epoxy equivalent, thus affecting the crosslinking density and mechanical property stability of the cured product. Furthermore, precisely controlling the synthesis process to maintain a reasonable melt viscosity while improving the resin's heat resistance, achieving a balance in overall performance, remains a difficult and hot research topic in this field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, a high heat-resistant biphenyl phenolic epoxy resin, its preparation method, and its applications are provided.

[0006] The objective of this invention is achieved through the following technical solution: In a first aspect, the present invention provides a method for preparing a high heat-resistant biphenyl phenolic epoxy resin, comprising, Phenol-biphenyl-type resin, epichlorohydrin, cosolvent I, etherification catalyst, and 10-20% sodium hydroxide aqueous solution are mixed to carry out an etherification reaction. Then, 45-50% sodium hydroxide solution is added under a negative pressure of -0.08 to -0.06 MPa to carry out a ring-closing reaction. After the first post-treatment, cosolvent I and epichlorohydrin are recovered to obtain crude biphenyl phenol formaldehyde epoxy resin. The crude biphenyl phenolic epoxy resin is dissolved in co-solvent II, and a phase transfer catalyst and 10-20% sodium hydroxide aqueous solution are added for purification reaction. After a second post-treatment, co-solvent II is recovered to obtain high heat-resistant biphenyl phenolic epoxy resin. In the etherification reaction, the etherification catalyst is a quaternary ammonium salt, selected from one of tetramethylammonium chloride, tetraethylammonium chloride, benzyltriethylammonium bromide, benzyltriethylammonium chloride, tetramethylammonium bromide, and tetraethylammonium bromide; the molar ratio of phenol-biphenyl resin to epichlorohydrin is 1:3.0-4.5, and the molar ratio of phenol-biphenyl resin to sodium hydroxide in a 10-20% sodium hydroxide aqueous solution is 1:0.15-0.20; In the purification reaction, the molar ratio of total chlorine in the crude biphenyl phenolic epoxy resin to sodium hydroxide in a 10-20% sodium hydroxide aqueous solution is 1:5-6, and the phase transfer catalyst is selected from benzyltriethylammonium bromide and benzyltriethylammonium chloride.

[0007] In some specific embodiments of the present invention, the molar ratio of the phenol-biphenyl type resin to epichlorohydrin is 1:3.5 to 4.2.

[0008] In some specific embodiments of the present invention, the molar ratio of the phenol-biphenyl type resin to epichlorohydrin is 1:3.9 to 4.0.

[0009] In some specific embodiments of the present invention, the co-solvent I is a hydrophobic organic solvent selected from at least one of toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, and butanone.

[0010] In some specific embodiments of the present invention, the molar ratio of the phenol-biphenyl type resin to cosolvent I is 1:0.6 to 1.35.

[0011] In some specific embodiments of the present invention, the molar ratio of the phenol-biphenyl type resin to cosolvent I is 1:0.8 to 1.2.

[0012] In some specific embodiments of the present invention, the molar ratio of the phenol-biphenyl type resin to cosolvent I is 1:0.85 to 0.95.

[0013] In some specific embodiments of the present invention, the co-solvent II is a hydrophobic organic solvent selected from at least one of toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, and butanone.

[0014] In some specific embodiments of the present invention, the reaction temperature of the etherification reaction is 40~50℃ and the reaction time is 2~2.5 h.

[0015] In some specific embodiments of the present invention, the reaction temperature of the closed-loop reaction is 60~65℃ and the reaction time is 4~6h.

[0016] In some specific embodiments of the present invention, the cosolvent II is selected from at least one of toluene and methyl isobutyl ketone.

[0017] In some specific embodiments of the present invention, the reaction temperature of the purification reaction is 55~60℃ and the reaction time is 2~2.5h.

[0018] In some specific embodiments of the present invention, the first post-processing includes, Nitrogen gas was used to break the vacuum, pure water was added, and the mixture was washed repeatedly until neutral. Excess epichlorohydrin and cosolvent I were removed under reduced pressure, and then residual epichlorohydrin and cosolvent I were removed by bubbling with nitrogen gas.

[0019] In some specific embodiments of the present invention, the second post-processing includes, Wash the mixture with pure water until the water layer is neutral, then filter it through diatomaceous earth to remove insoluble matter, remove co-solvent II under negative pressure, and finally remove the residual co-solvent II by bubbling with nitrogen.

[0020] In a second aspect, the present invention provides a high heat-resistant biphenyl phenolic epoxy resin prepared by the preparation method described in the first aspect, wherein the high heat-resistant biphenyl phenolic epoxy resin has an epoxy equivalent of 260~265 g / mol, total chlorine <500 ppm, organic chlorine <50 ppm, and a softening point of 50~60℃.

[0021] Thirdly, the present invention provides an application of the high heat-resistant biphenyl phenolic epoxy resin described in the second aspect in electronic component packaging materials.

[0022] The beneficial effects achieved by this invention are as follows: (1) The method for preparing high heat-resistant biphenyl phenol aldehyde epoxy resin provided by the present invention solves the problem of reaction difficulty caused by the rigidity defect of phenol-biphenyl resin by using quaternary ammonium salt and low concentration alkali solution to catalyze the etherification reaction, and can slow down the ring-opening reaction at the β position to reduce the total chlorine, and greatly reduce the amount of epichlorohydrin and cosolvent used, thus reducing the waste of resources.

[0023] (2) The method for preparing high heat-resistant biphenyl phenolic epoxy resin provided by the present invention controls the proportion of epichlorohydrin in the etherification stage to reduce the ring-opening reaction activity, reduce the generation of β-Cl, and thus reduce the total chlorine.

[0024] (3) The method for preparing high heat-resistant biphenyl aldehyde epoxy resin provided by the present invention reduces the total chlorine in the etherification reaction stage. In the purification reaction, a low concentration of alkaline solution is used and the molar ratio of the total chlorine of the crude biphenyl aldehyde epoxy resin to sodium hydroxide in the sodium hydroxide aqueous solution is controlled within the range of 1:5~6. This reduces the organic chlorine content to below 50ppm while preventing explosive polymerization and excessive intermediate layer formation, reducing by-products and increasing yield. This achieves the dual effect of improving production efficiency and product quality.

[0025] Insufficient alkali ratio during the refining stage cannot reduce organochlorine, while excessive ratio will cause the closed-ring product to open again, resulting in high epoxy equivalent, increased organochlorine, and problems such as explosive polymerization and more intermediate layers.

[0026] (4) The high heat-resistant biphenyl phenolic epoxy resin prepared by the preparation method provided by the present invention has an epoxy equivalent as low as 260~265 g / moL, a high crosslinking density and high heat resistance after curing, and a total chlorine content of <500 ppm and an organic chlorine content of <50 ppm. It has little impact on light efficiency and color temperature during encapsulation, reduces metal circuit corrosion after electronic component encapsulation, and has a softening point of 50~60℃. It has good processing fluidity and is suitable for use as an encapsulation material. Attached Figure Description

[0027] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a synthesis path diagram of Embodiment 1 of the present invention.

[0029] Figure 2 The image shows the GPC spectrum of the product obtained in Example 1 of this invention.

[0030] Figure 3 The infrared spectrum of the product obtained in Example 1 of this invention is shown. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to specific embodiments. The following embodiments are not intended to limit the present invention, but only to illustrate the present invention. Unless otherwise specified, the experimental methods used in the following embodiments are generally performed under conventional conditions. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.

[0032] The epoxy equivalent of the high heat-resistant biphenyl phenolic epoxy resin in this invention is tested according to GB / T4612-2008, "Determination of Epoxy Equivalent of Epoxy Compounds in Plastics". The specific test method is as follows: Take a sample containing 0.6 mmol / L to 0.9 mmol / L of epoxy groups, where the sample mass is in the range of (0.6 × EE ~ 0.9 × EE) mg, and EE is the estimated epoxy equivalent of the sample. Add 10 mL of chloroform, stir and heat to dissolve the sample, cool to room temperature, add 20 mL of glacial acetic acid and 10 mL of tetraethylammonium bromide solution, and use potentiometric titration. Place the electrode in the sample and titrate the solution with perchloric acid solution. Record the temperature t of the perchloric acid solution to correct for the volume of the solution when the temperature changes. Simultaneously, a blank test is performed, which is conducted using the same steps and reagents, but without a sample.

[0033] In this invention, the inorganic chlorine content of the high heat-resistant biphenyl phenolic epoxy resin is determined according to GB / T4618.1-2008, Determination of Chlorine Content in Plastic Epoxy Resins Part 1: Inorganic Chlorine. The specific test method is as follows: Weigh 10.0 g of the sample into a 200 mL beaker, add 100 mL of acetone, and stir magnetically to dissolve. Add 2 mL of water and 1 mL of glacial acetic acid. Place the beaker on a burette and adjust the electrode so that it is immersed in about 1 / 2 of the liquid surface. Fill the microburette with 0.002 mol / L AgNO3 solution, immersing the tip of the burette about 10 mm below the liquid surface. Record the initial reading of the burette and the initial potential value. Add small amounts of AgNO3 solution successively, recording the volume and potential after each addition when the potential stabilizes. If the potential change in the inflection point region is small, the increment is 0.1 mL each time; if the potential change rate is >5 mV / 0.02 mL, the increment is reduced to 0.02 mL each time. Continue titrating until the rate of change of potential is <2 mV / 0.02 mL, indicating that the endpoint has been reached. Plot the cumulative volume-potential curve, taking the midpoint of the inflection point as the endpoint, and read the endpoint volume V. Perform a blank test in the same way and record the blank endpoint volume V0.

[0034] The organochlorine content of the high heat-resistant biphenyl phenolic epoxy resin in this invention is determined according to GB / T 4618.2-2008 Determination of Chlorine Content in Plastic Epoxy Resins Part 2: Saponifiable Chlorine. The specific test method is as follows: Weigh a sample containing 1.78 mg or less of saponifiable chlorine, add 25 mL of 2-butoxyethanol, stir and heat to dissolve the sample, cool to room temperature, take 25 mL of sodium hydroxide in 2-butoxyethanol solution and mix thoroughly. Let the mixture stand at room temperature for 2 h, add 100 mL of butanone and 25 mL of glacial acetic acid to the mixture and stir until the precipitate is completely dissolved. Place the electrode in the sample solution and perform potentiometric titration with silver nitrate standard solution.

[0035] The total chlorine content of the high heat-resistant biphenyl phenolic epoxy resin in this invention is determined according to GB / T 4618.3-2008 Plastic Epoxy Resin Determination of Chlorine Content Part 3: Total Chlorine. The specific test method is as follows: When weighing the sample, if the expected total chlorine content is less than 1%, weigh a sample containing 0.5~1.5 mg of chlorine; if the expected total chlorine content is greater than 1%, weigh a sample containing 5~15 mg of chlorine. Then, add 25 mL of diethylene glycol butyl ether and stir to dissolve the sample. Subsequently, add 25 mL of potassium hydroxide in 1,2-propanediol solution. While stirring, heat the solution under reflux for 10 min. After cooling, pour 5 mL of acetone into a reflux condenser and transfer the solution from the flask to a 200 mL beaker. The inside of the flask was washed three times with a total of 50 mL of glacial acetic acid, and the washing solution was added to the solution in the beaker. The electrode was placed in the solution. If the expected total chlorine content was less than 1%, potentiometric titration was performed with 0.01 mol / L silver nitrate solution. If the expected total chlorine content was greater than 1%, potentiometric titration was performed with 0.1 mol / L silver nitrate solution. Blank tests were performed using the same method.

[0036] The softening point test method for the high heat-resistant biphenyl phenolic epoxy resin in this invention is the ring and ball method, with glycerol as the heating medium. The specific test method is as follows: (1) Place about 10 pieces of resin in a beaker and put it in an oven. Heat the beaker for 30 minutes at a temperature 60°C higher than the estimated softening point of the resin to melt it. At the same time, preheat the copper ring to a temperature close to that at which the resin is poured. Place the preheated copper ring on a smooth copper or aluminum sheet coated with silicone grease, and pour the molten resin into the copper ring so that the liquid level is slightly higher than the ring surface. Cool the sample at room temperature, remove the metal plate, and use a clean knife to smooth out any excess resin on the ring surface. Cool the sample at room temperature for another 30 minutes.

[0037] (2) Cool the freshly boiled distilled water to 45°C below the estimated softening point, add it to the beaker, and control the height to 100-108 mm. Fix the stirrer drive shaft to the circular plate of the support, so that the bottom of its blades is 19 mm higher than the top of the copper ring. The stirring motor should be installed in a position that will not cause vibration of the sample holder during stirring. Install the copper ring containing resin and the steel ball centering guide on the ring frame. After immersing the steel ball in water for 15 minutes, place it in the center of the ring surface with tweezers and insert the thermometer along the center hole of the support. Start the stirrer until the test is completed. Heat the beaker with an electric furnace, raising the water temperature at a rate of 5°C / min until the resin softens and the temperature indicated by the thermometer when the steel ball falls to the bottom plate is the softening point.

[0038] The yield calculation formula in this embodiment of the invention is: Yield = Actual product mass obtained after refining / Theoretical epoxy resin mass × 100%, wherein the specific calculation method of the theoretical epoxy resin mass is: Biphenyl phenol type resin mass ÷ (hydroxyl equivalent of biphenyl phenol type resin × 2) × (hydroxyl equivalent of biphenyl phenol type resin × 2 + 56 × 2).

[0039] The phenol-biphenyl resin used in the embodiments of the present invention was purchased from Beijing Odyssey Chemical Co., Ltd., with a hydroxyl equivalent of 195 g / mol; epichlorohydrin was purchased from Zibo Shengbo Trade Co., Ltd.

[0040] Example 1

[0041] This embodiment provides a method for preparing a high heat-resistant biphenyl phenolic epoxy resin, specifically as follows: (1) Etherification reaction: In a 2L glass reactor equipped with a thermometer, stirrer, dropping funnel and condenser, 330 g (0.84 mol) of phenol-biphenyl resin, 310 g (3.36 mol) of epichlorohydrin and 93 g of methyl isobutyl ketone were added in sequence and dissolved at 80℃ for 1 h; the temperature was lowered to 50℃ and 3.3 g of benzyltriethylammonium bromide was added, followed by 28 g of 20% sodium hydroxide aqueous solution, and the reaction was carried out for 2 h.

[0042] (2) Closed-loop reaction: Heat to 60℃, set up a water separator, then turn on the vacuum, the vacuum degree is -0.07 MPa, add 158 g of 50% sodium hydroxide solution of closed-loop catalyst within 4 h, and continue the reaction for 2 h after the addition is completed; After the reaction was completed, nitrogen was used to break the vacuum, and 253 g of pure water was added. The mixture was stirred until the temperature reached 60°C. After standing and separating the liquids, the mixture was washed repeatedly with water until neutral. Then, excess epichlorohydrin and methyl isobutyl ketone were removed under reduced pressure (-0.09 MPa, 140°C). Finally, residual epichlorohydrin and methyl isobutyl ketone were removed by bubbling with nitrogen to obtain crude biphenyl phenolic epoxy resin. The total chlorine content of the crude product was calculated to be 1085 ppm.

[0043] (3) Purification reaction: Add 720 g of methyl isobutyl ketone to dissolve the crude resin again. When the temperature reaches 55°C, add 5 g of benzyltriethylammonium chloride and 25 g of 10% sodium hydroxide aqueous solution to the crude resin mixture and let the reaction proceed at 55°C for 2 h. After the reaction is complete, the mixture is washed with pure water until the water layer is neutral. Then, the insoluble matter is removed by diatomaceous earth filtration. The filtrate is transferred to another reactor for negative pressure removal of methyl isobutyl ketone. The negative pressure vacuum degree is controlled at 0.8-0.9 MPa. Finally, nitrogen is used to bubble the residual methyl isobutyl ketone to obtain a light yellow solid product.

[0044] Figure 1 This is the synthesis path diagram for Example 1.

[0045] The GPC spectrum of the product in Test Example 1 is as follows: Figure 2 As shown, the ring-closing reaction is complete, the oligomer distribution is narrow, and there are no excessively high molecular weight components or residual small molecules of phenol glycidyl ether. The FT-IR spectrum of the product from Example 1 is also shown below. Figure 3 As shown, there are no residual phenolic hydroxyl groups, proving that the etherification is sufficient and meets the oligomer distribution requirements of the encapsulation material.

[0046] Example 2

[0047] This embodiment provides a method for preparing a high heat-resistant biphenyl phenolic epoxy resin, specifically as follows: (1) Etherification reaction: In a 2L glass reactor equipped with a thermometer, stirrer, dropping funnel and condenser, 330 g (0.84 mol) of phenol-biphenyl resin, 310 g (3.36 mol) of epichlorohydrin and 93 g of toluene were added in sequence and dissolved at 80℃ for 1 h; the temperature was lowered to 50℃ and 3.3 g of tetramethylammonium bromide was added, followed by 28 g of 20% sodium hydroxide aqueous solution, and the reaction was carried out for 2 h.

[0048] (2) Closed-loop reaction: Heat to 60℃, set up a water separator, then turn on the vacuum, the vacuum degree is -0.07 MPa, add 158 g of 50% sodium hydroxide solution of closed-loop catalyst within 4 h, and continue the reaction for 2 h after the addition is completed; After the reaction was completed, nitrogen was used to break the vacuum, and 253 g of pure water was added. The mixture was stirred until the temperature reached 60°C. After standing and separating the liquids, the mixture was washed repeatedly with water until neutral. Then, excess epichlorohydrin and toluene were removed under reduced pressure (-0.09 MPa, 140°C). Finally, nitrogen was used to bubble the remaining epichlorohydrin and toluene to obtain crude biphenyl phenolic epoxy resin. The total chlorine content of the crude product was calculated to be 1205 ppm.

[0049] (3) Refining reaction: Add 720 g of toluene to dissolve the crude resin again. When the temperature reaches 55°C, add 5 g of benzyltriethylammonium chloride and 25 g of 10% sodium hydroxide aqueous solution to the crude resin mixture and let the reaction proceed at 55°C for 2 hours. After the reaction is complete, the mixture is washed with pure water until the aqueous layer is neutral. Then, the insoluble matter is removed by diatomaceous earth filtration. The filtrate is transferred to another reactor for negative pressure removal of toluene. The negative pressure vacuum degree is controlled at 0.8-0.9 MPa. Finally, nitrogen is used to bubble the remaining toluene to remove the product, resulting in a light yellow solid product.

[0050] Example 3

[0051] This embodiment provides a method for preparing a high heat-resistant biphenyl phenolic epoxy resin, specifically as follows: (1) Etherification reaction: In a 2L glass reactor equipped with a thermometer, stirrer, dropping funnel and condenser, 330 g (0.84 mol) of phenol-biphenyl resin, 310 g (3.36 mol) of epichlorohydrin and 93 g of butanone were added in sequence and dissolved at 80℃ for 1 h; the temperature was lowered to 50℃ and 3.3 g of benzyltriethylammonium chloride was added, followed by 28 g of 20% sodium hydroxide aqueous solution, and the reaction was carried out for 2 h.

[0052] (2) Closed-loop reaction: Heat to 60℃, set up a water separator, then turn on the vacuum, the vacuum degree is -0.07 MPa, add 158 g of 50% sodium hydroxide solution of closed-loop catalyst within 4 h, and continue the reaction for 2 h after the addition is completed; After the reaction was completed, nitrogen was used to break the vacuum, and 253 g of pure water was added. The mixture was stirred until the temperature reached 60°C. After standing and separating the liquids, the mixture was washed repeatedly with water until neutral. Then, excess epichlorohydrin and butanone were removed under reduced pressure (-0.09 MPa, 140°C). Finally, residual epichlorohydrin and butanone were removed by bubbling with nitrogen to obtain crude biphenyl phenolic epoxy resin. The total chlorine content of the crude product was calculated to be 1050 ppm.

[0053] (3) Purification reaction: Add 720 g of methyl isobutyl ketone to dissolve the crude resin again. When the temperature reaches 55°C, add 5 g of benzyltriethylammonium chloride and 25 g of 10% sodium hydroxide aqueous solution to the crude resin mixture and let the reaction proceed at 55°C for 2 h. After the reaction is complete, the mixture is washed with pure water until the water layer is neutral. Then, the insoluble matter is removed by diatomaceous earth filtration. The filtrate is transferred to another reactor for negative pressure removal of methyl isobutyl ketone. The negative pressure vacuum degree is controlled at 0.8-0.9 MPa. Finally, nitrogen is used to bubble the residual methyl isobutyl ketone to obtain a light yellow solid product.

[0054] Example 4

[0055] This embodiment provides a method for preparing a high heat-resistant biphenyl phenolic epoxy resin, specifically as follows: (1) Etherification reaction: In a 2L glass reactor equipped with a thermometer, stirrer, dropping funnel and condenser, 330 g (0.84 mol) of phenol-biphenyl resin, 310 g (3.36 mol) of epichlorohydrin and 93 g of methyl ethyl ketone were added in sequence and dissolved at 80℃ for 1 h; the temperature was lowered to 50℃ and 3.3 g of benzyltriethylammonium chloride was added, followed by 28 g of 20% sodium hydroxide aqueous solution, and the reaction was carried out for 2 h.

[0056] (2) Closed-loop reaction: Heat to 60℃, set up a water separator, then turn on the vacuum, the vacuum degree is -0.07 MPa, add 158 g of 50% sodium hydroxide solution of closed-loop catalyst within 4 h, and continue the reaction for 2 h after the addition is completed; After the reaction was completed, nitrogen was used to break the vacuum, and 253 g of pure water was added. The mixture was stirred until the temperature reached 60°C. After standing and separating the liquids, the mixture was washed repeatedly with water until neutral. Then, excess epichlorohydrin and methyl ethyl ketone were removed under reduced pressure (-0.09 MPa, 140°C). Finally, nitrogen was used to bubble the remaining epichlorohydrin and the cosolvent methyl ethyl ketone to obtain crude biphenyl phenolic epoxy resin. The total chlorine content of the crude product was calculated to be 1180 ppm.

[0057] (3) Refining reaction: Add 720 g of toluene to dissolve the crude resin again. When the temperature reaches 55°C, add 5 g of benzyltriethylammonium bromide and 25 g of 10% sodium hydroxide aqueous solution to the crude resin mixture and let the reaction proceed at 55°C for 2 h. After the reaction is complete, the mixture is washed with pure water until the aqueous layer is neutral. Then, the insoluble matter is removed by diatomaceous earth filtration. The filtrate is transferred to another reactor for negative pressure removal of toluene. The negative pressure vacuum degree is controlled at 0.8-0.9 MPa. Finally, nitrogen is used to bubble the remaining toluene to remove the product, resulting in a light yellow solid product.

[0058] Comparative Example 1

[0059] The difference between this comparative example and Example 1 is that only the concentration of the etherification alkali solution is adjusted to 30%, specifically: (1) Etherification reaction: In a 2L glass reactor equipped with a thermometer, stirrer, dropping funnel and condenser, 330 g (0.84 mol) of phenol-biphenyl resin, 310 g (3.36 mol) of epichlorohydrin and 93 g of methyl isobutyl ketone were added in sequence and dissolved at 80℃ for 1 h; the temperature was lowered to 50℃ and 3.3 g of benzyltriethylammonium bromide was added, followed by 18.6 g of 30% sodium hydroxide aqueous solution, and the reaction was carried out for 2 h.

[0060] (2) Closed-loop reaction: Heat to 60℃, set up a water separator, then turn on the vacuum, the vacuum degree is -0.07 MPa, add 158 g of 50% sodium hydroxide solution of closed-loop catalyst within 4 h, and continue the reaction for 2 h after the addition is completed; After the reaction was completed, nitrogen was used to break the vacuum, and 253 g of pure water was added. The mixture was stirred until the temperature reached 60°C. After standing and separating the liquids, the mixture was washed repeatedly with water until neutral. Then, excess epichlorohydrin and methyl isobutyl ketone were removed under reduced pressure (-0.09 MPa, 140°C). Finally, residual epichlorohydrin and the cosolvent methyl isobutyl ketone were removed by bubbling with nitrogen to obtain crude biphenyl phenolic epoxy resin. The total chlorine content of the crude product was calculated to be 1450 ppm.

[0061] (3) Purification reaction: Add 720 g of methyl isobutyl ketone to dissolve the crude resin again. When the temperature reaches 55°C, add 5 g of benzyltriethylammonium chloride and 25 g of 10% sodium hydroxide aqueous solution to the crude resin mixture and let the reaction proceed at 55°C for 2 h. After the reaction is complete, the mixture is washed with pure water until the water layer is neutral. Then, the insoluble matter is removed by diatomaceous earth filtration. The filtrate is transferred to another reactor for negative pressure removal of methyl isobutyl ketone. The negative pressure vacuum degree is controlled at 0.8-0.9 MPa. Finally, nitrogen is used to bubble the residual methyl isobutyl ketone to obtain a light yellow solid product.

[0062] Comparative Example 2

[0063] The difference between this comparative example and Example 1 is that only the concentration of the etherification alkali solution is adjusted to 5%, specifically: (1) Etherification reaction: In a 2L glass reactor equipped with a thermometer, stirrer, dropping funnel and condenser, 330 g (0.84 mol) of phenol-biphenyl resin, 310 g (3.36 mol) of epichlorohydrin and 93 g of methyl isobutyl ketone were added in sequence and dissolved at 80℃ for 1 h; the temperature was lowered to 50℃ and 3.3 g of benzyltriethylammonium bromide was added, followed by 112 g of 5% sodium hydroxide aqueous solution, and the reaction was carried out for 2 h.

[0064] (2) Closed-loop reaction: Heat to 60℃, set up a water separator, then turn on the vacuum, the vacuum degree is -0.07 MPa, add 158 g of 50% sodium hydroxide solution of closed-loop catalyst within 4 h, and continue the reaction for 2 h after the addition is completed; After the reaction was completed, nitrogen was used to break the vacuum, and 253 g of pure water was added. The mixture was stirred until the temperature reached 60°C. After standing and separating the liquids, the mixture was washed repeatedly with water until neutral. Then, excess epichlorohydrin and methyl isobutyl ketone were removed under reduced pressure at -0.09 MPa and 140°C. Finally, residual epichlorohydrin and methyl isobutyl ketone were removed by bubbling with nitrogen to obtain crude biphenyl phenolic epoxy resin. The total chlorine content of the crude product was calculated to be 1388 ppm.

[0065] (3) Purification reaction: Add 720 g of methyl isobutyl ketone to dissolve the crude resin again. When the temperature reaches 55°C, add 5 g of benzyltriethylammonium chloride and 25 g of 10% sodium hydroxide aqueous solution to the crude resin mixture and let the reaction proceed at 55°C for 2 h. After the reaction is complete, the mixture is washed with pure water until the water layer is neutral. Then, the insoluble matter is removed by diatomaceous earth filtration. The filtrate is transferred to another reactor for negative pressure removal of methyl isobutyl ketone. The negative pressure vacuum degree is controlled at 0.8-0.9 MPa. Finally, nitrogen is used to bubble the residual methyl isobutyl ketone to obtain a light yellow solid product.

[0066] Comparative Example 3

[0067] The difference between this comparative example and Example 1 is that only the molar ratio of the refined alkaline solution, i.e., the total chlorine of the crude biphenyl phenolic epoxy resin and the sodium hydroxide in the 10% sodium hydroxide aqueous solution, is adjusted to 1:4, specifically: (1) Etherification reaction: In a 2L glass reactor equipped with a thermometer, stirrer, dropping funnel and condenser, 330 g (0.84 mol) of phenol-biphenyl resin, 310 g (3.36 mol) of epichlorohydrin and 93 g of methyl isobutyl ketone were added in sequence and dissolved at 80℃ for 1 h; the temperature was lowered to 50℃ and 3.3 g of benzyltriethylammonium bromide was added, followed by 28 g of 20% sodium hydroxide aqueous solution, and the reaction was carried out for 2 h.

[0068] (2) Closed-loop reaction: Heat to 60℃, set up a water separator, then turn on the vacuum, the vacuum degree is -0.07 MPa, add 158 g of 50% sodium hydroxide solution of closed-loop catalyst within 4 h, and continue the reaction for 2 h after the addition is completed; After the reaction was completed, nitrogen was used to break the vacuum, and 253 g of pure water was added. The mixture was stirred until the temperature reached 60°C. After standing and separating the liquids, the mixture was washed repeatedly with water until neutral. Then, excess epichlorohydrin and methyl isobutyl ketone were removed under reduced pressure (-0.09 MPa, 140°C). Finally, residual epichlorohydrin and the cosolvent methyl isobutyl ketone were removed by bubbling with nitrogen to obtain crude biphenyl phenolic epoxy resin. The total chlorine content of the crude product was calculated to be 1489 ppm.

[0069] (3) Purification reaction: Add 720 g of methyl isobutyl ketone to dissolve the crude resin again. When the temperature reaches 55°C, add 5 g of benzyltriethylammonium chloride and 20 g of 10% sodium hydroxide aqueous solution to the crude resin mixture and let the reaction proceed at 55°C for 2 h. After the reaction is complete, the mixture is washed with pure water until the water layer is neutral. Then, the insoluble matter is removed by diatomaceous earth filtration. The filtrate is transferred to another reactor for negative pressure removal of methyl isobutyl ketone. The negative pressure vacuum degree is controlled at 0.8-0.9 MPa. Finally, nitrogen is used to bubble the residual methyl isobutyl ketone to obtain a light yellow solid product.

[0070] Comparative Example 4

[0071] The difference between this comparative example and Example 1 is that only the ratio of the refined alkaline solution, i.e., the molar ratio of the total chlorine in the crude biphenyl phenolic epoxy resin to the sodium hydroxide in the sodium hydroxide aqueous solution, is adjusted to 1:7, specifically: (1) Etherification reaction: In a 2L glass reactor equipped with a thermometer, stirrer, dropping funnel and condenser, 330 g (0.84 mol) of phenol-biphenyl resin, 310 g (3.36 mol) of epichlorohydrin and 93 g of methyl isobutyl ketone were added in sequence and dissolved at 80℃ for 1 h; the temperature was lowered to 50℃ and 3.3 g of benzyltriethylammonium bromide was added, followed by 28 g of 20% sodium hydroxide aqueous solution, and the reaction was carried out for 2 h.

[0072] (2) Closed-loop reaction: Heat to 60℃, set up a water separator, then turn on the vacuum, the vacuum degree is -0.07 MPa, add 158 g of 50% sodium hydroxide solution of closed-loop catalyst within 4 h, and continue the reaction for 2 h after the addition is completed; After the reaction was completed, nitrogen was used to break the vacuum, and 253 g of pure water was added. The mixture was stirred until the temperature reached 60°C. After standing and separating the liquids, the mixture was washed repeatedly with water until neutral. Then, excess epichlorohydrin and methyl isobutyl ketone were removed under reduced pressure (-0.09 MPa, 140°C). Finally, residual epichlorohydrin and methyl isobutyl ketone were removed by bubbling with nitrogen to obtain crude biphenyl phenolic epoxy resin. The total chlorine content of the crude product was calculated to be 1580 ppm.

[0073] (3) Purification reaction: Add 720 g of methyl isobutyl ketone to dissolve the crude resin again. When the temperature reaches 55°C, add 5 g of benzyltriethylammonium chloride and 36 g of 10% sodium hydroxide aqueous solution to the crude resin mixture and let the reaction proceed at 55°C for 2 h. After the reaction is complete, the mixture is washed with pure water until the water layer is neutral. Then, the insoluble matter is removed by diatomaceous earth filtration. The filtrate is transferred to another reactor for negative pressure removal of methyl isobutyl ketone. The negative pressure vacuum degree is controlled at 0.8-0.9 MPa. Finally, nitrogen is used to bubble the residual methyl isobutyl ketone to obtain a light yellow solid product.

[0074] The yield, epoxy equivalent, total chlorine, organic chlorine, inorganic chlorine, and softening point of the products of Examples 1-4 and Comparative Examples 1-4 were tested and calculated, and the results are shown in Tables 1 and 2.

[0075] Table 1. Yields, epoxy equivalents, and softening points of the products from Examples 1-4 and Comparative Examples 1-4

[0076] Table 2 Total chlorine, organic chlorine, and inorganic chlorine in the products of Examples 1-4 and Comparative Examples 1-4

[0077] In summary, the method for preparing high heat-resistant biphenyl phenolic epoxy resin provided by this invention involves the synergistic catalytic etherification of phenol-biphenylene resin by quaternary ammonium salt and low-concentration alkaline solution followed by a purification reaction. The resulting product has low chlorine content, a moderate softening point, total chlorine < 500 ppm, and organic chlorine < 50 ppm, making it suitable for high-end electronic packaging materials such as EMC, LED reflectors, and high-frequency copper-clad laminates.

[0078] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a high heat-resistant biphenyl phenolic epoxy resin, characterized in that: include, Phenol-biphenyl-type resin, epichlorohydrin, cosolvent I, etherification catalyst, and 10-20% sodium hydroxide aqueous solution are mixed to carry out an etherification reaction. Then, 45-50% sodium hydroxide solution is added under a negative pressure of -0.08 to -0.06 MPa to carry out a ring-closing reaction. After the first post-treatment, cosolvent I and epichlorohydrin are recovered to obtain crude biphenyl phenol formaldehyde epoxy resin. The crude biphenyl phenolic epoxy resin is dissolved in co-solvent II, and a phase transfer catalyst and 10-20% sodium hydroxide aqueous solution are added for purification reaction. After a second post-treatment, co-solvent II is recovered to obtain high heat-resistant biphenyl phenolic epoxy resin. In the etherification reaction, the etherification catalyst is a quaternary ammonium salt, which is selected from one of tetramethylammonium chloride, tetraethylammonium chloride, benzyltriethylammonium bromide, benzyltriethylammonium chloride, tetramethylammonium bromide, and tetraethylammonium bromide; the molar ratio of phenol-biphenyl resin to epichlorohydrin is 1:3.0-4.5, and the molar ratio of phenol-biphenyl resin to sodium hydroxide in 10-20% sodium hydroxide aqueous solution is 1:0.15-0.20; In the purification reaction, the molar ratio of total chlorine in the crude biphenyl phenolic epoxy resin to sodium hydroxide in a 10-20% sodium hydroxide aqueous solution is 1:5-6, and the phase transfer catalyst is selected from benzyltriethylammonium bromide and benzyltriethylammonium chloride.

2. The preparation method according to claim 1, characterized in that: The cosolvent I is a hydrophobic organic solvent selected from at least one of toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, and butanone.

3. The preparation method according to claim 2, characterized in that: The molar ratio of the phenol-biphenyl type resin to cosolvent I is 1:0.6 to 1.

35.

4. The preparation method according to claim 1, characterized in that: The etherification reaction is carried out at a temperature of 40-50°C for 2-2.5 h.

5. The preparation method according to claim 1, characterized in that: The closed-loop reaction is carried out at a temperature of 60-65°C for 4-6 hours.

6. The preparation method according to claim 1, characterized in that: The cosolvent II is selected from at least one of toluene and methyl isobutyl ketone.

7. The preparation method according to claim 1, characterized in that: The refining reaction is carried out at a temperature of 55-60°C for 2-2.5 hours.

8. The preparation method according to claim 1, characterized in that: The first post-processing includes, Nitrogen gas was used to break the vacuum, pure water was added, and the mixture was washed repeatedly until neutral. Excess epichlorohydrin and cosolvent I were removed under reduced pressure, and then residual epichlorohydrin and cosolvent I were removed by bubbling with nitrogen gas. The second post-processing includes, Wash the mixture with pure water until the water layer is neutral, then filter it through diatomaceous earth to remove insoluble matter, remove co-solvent II under negative pressure, and finally remove the residual co-solvent II by bubbling with nitrogen.

9. A high heat-resistant biphenyl phenolic epoxy resin prepared by any one of the preparation methods according to claims 1 to 8, characterized in that: The high heat-resistant biphenyl phenolic epoxy resin has an epoxy equivalent of 260~265 g / mol, total chlorine <500 ppm, organic chlorine <50 ppm, and a softening point of 50~60℃.

10. The application of the high heat-resistant biphenyl phenolic epoxy resin of claim 9 in electronic component encapsulation materials.

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