Preparation method of electronic-grade epoxy resin

Abstract

The invention discloses a preparation method of electronic-grade epoxy resin, and relates to the technical field of epoxy resin, and the preparation method comprises the following steps: S1, preparing and mixing raw materials: according to detection data of total chlorine in the epoxy resin, preparing a dechlorinating agent with corresponding metering, and uniformly mixing the epoxy resin and the dechlorinating agent; s2, heating reaction: heating the mixed material under the protection of nitrogen, and removing low-boiling-point substances at the same time; s3, molecular distillation separation: continuously distilling to obtain low-total-chlorine target resin, and removing chlorine-containing polymer impurities out of the system in a kettle residue form; and S4, product collection and detection. According to the preparation method of the electronic-grade epoxy resin, the chlorine removal agent is accurately metered and uniformly mixed with the epoxy resin, the mixture is heated and reacted under the protection of nitrogen, low-boiling-point substances and chlorine-containing impurities are effectively removed, continuous distillation is performed by utilizing a molecular distillation technology, low-total-chlorine target resin is further successfully separated, and the total chlorine content in the epoxy resin is remarkably reduced.

Description

Technical Field

[0001] This invention relates to the field of epoxy resin technology, specifically to a method for preparing electronic-grade epoxy resin. Background Technology

[0002] In today's rapidly developing electronics industry, electronic-grade epoxy resins are key materials, and their performance, especially their chlorine content, directly affects the quality and reliability of electronic products. Glycidyl ether epoxy resins are a common type of epoxy resin, typically prepared by a ring-opening etherification-saponification ring-closing reaction of phenols or alcohols and epichlorohydrin under the action of a catalyst. However, in actual production, this reaction has many problems, leading to the generation of various impurities in the reaction system, among which the problem of excessively high chlorine content is particularly prominent.

[0003] First, ectopic ring-opening (β-ring-opening in the attached diagram) occurs during ring-opening etherification. Phenolic compounds such as bisphenol A and epichlorohydrin exhibit ring-opening selectivity >90%, while alcohols and epichlorohydrin exhibit ring-opening selectivity ≤85%. This ectopic ring-opening alters the reaction pathway, affecting the purity and structure of the product and introducing chlorine-containing impurities. Second, epichlorohydrin itself is prone to hydrolysis and subsequent side reactions. The hydrolysis of epichlorohydrin in the reaction system generates byproducts such as chloroalcohols, which may further participate in the reaction, forming more complex impurity structures. Third, subsequent reactions of the ring-opening product can also cause problems. Under the reaction conditions, the ring-opening product may continue to react, such as rearrangement and cyclization. These reactions also produce chlorine-containing impurities that remain in the reaction system, affecting the performance of the epoxy resin.

[0004] For the reasons mentioned above, residual hydrolyzable chlorine, non-hydrolyzable chlorine, and inorganic chloride ions will be generated in the reaction system. These impurities are collectively referred to as total chlorine. The total chlorine content significantly affects the electrical insulation properties, gel time, heat resistance, and mechanical properties after curing of epoxy resin, and is a key factor restricting the quality of electronic-grade epoxy resin.

[0005] To reduce total chlorine content, traditional methods involve precisely controlling the reaction temperature during production, and using liquid alkali dropwise combined with reduced-pressure azeotropic dehydration to lower the reaction temperature and reduce byproducts. However, such processes are demanding and have limitations on the quality of substrate raw materials. In post-treatment, while electrolysis and continuous alkali washing with dilute alkali can be used to reduce total chlorine, these methods are only effective for α-ring-opening products (1,2-chlorohydrin), with minimal effect on β-ring-opening products (1,3-chlorohydrin). This is because industry research on reducing chlorine content in epoxy resins primarily focuses on the latter.

[0006] For example, patent document CN115073712 discloses a method for preparing and applying low-chlorine epoxy resin. This invention uses polyfluoroalkane aldehydes in a perfluoroalkane solvent system to treat chlorine-containing impurities, and the effect is obvious with simple phase separation. However, this method requires the additional preparation of polyfluoroalkane aldehydes, and the method may lead to excessively high total fluorine levels.

[0007] Therefore, developing a universal, efficient, and cost-controllable solution for reducing total chlorine is of great significance for improving the product quality of electronic-grade epoxy resins. Summary of the Invention

[0008] The purpose of this invention is to provide a method for preparing electronic-grade epoxy resin to solve the problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing electronic-grade epoxy resin, applicable to a series of glycidyl ether and glycidyl ester epoxy resins, such as bisphenol A diglycidyl ether, 2,6-diallylphenyl glycidyl ether, bisphenol F diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hexahydrophthalic acid diglycidyl ester, etc. (the products can be separated by distillation), comprising the following steps: S1. Raw material preparation and mixing: Based on the detection data of total chlorine in epoxy resin, prepare the corresponding amount of dechlorinating agent, and mix the epoxy resin and dechlorinating agent evenly. S2, Heating reaction: The mixed materials are heated under nitrogen protection, while low-boiling substances are removed; S3. Molecular distillation separation: After the reaction is completed, the material is transferred to a molecular distillation device while it is still hot. In the molecular distillation device, the target resin with low total chlorine is separated from the chlorine-containing polymer impurities by continuous distillation. The chlorine-containing polymer impurities are removed from the system in the form of residue. S4. Product Collection and Testing: Collect the low-total-chlorine resin product obtained after distillation and test the total chlorine content of the product to ensure that it meets the requirements of electronic-grade epoxy resin.

[0010] Furthermore, in step S1, the dechlorination agent is selected from high molecular weight siloxanes, including but not limited to MS51, MS56, MS57, and MS56S, with MS51 being preferred.

[0011] Furthermore, in step S1, the amount of dechlorinating agent used is determined according to the total chlorine content in the resin. When the total chlorine content is 1000-10000 ppm, the preferred amount used is 0.2%-2.5% of the total resin mass; when the total chlorine content is 10000-55000 ppm, the preferred amount used is 2.5%-7.5%.

[0012] Furthermore, in step S2, the reaction temperature is 60-200℃, preferably 100-160℃.

[0013] Furthermore, at the reaction temperature, the dechlorinating agent reacts with chlorine-containing impurities in the resin (solvent-free reaction) to generate a small amount of low-boiling-point substances, which are then collected by condensation.

[0014] Furthermore, in step S2, the reaction equation using bisphenol A diglycidyl ether resin is illustrated below: R is either a chlorine-containing impurity produced in the reaction or a methyl group.

[0015] Furthermore, in step S3, impurities are separated by vacuum distillation, and after distillation, the low total chlorine resin exists in the light component collection tank of the molecular distillation equipment in the form of distillation product, while the chlorine-containing polymer impurities exist in the heavy component collection tank of the molecular distillation equipment in the form of residue.

[0016] Furthermore, in step S3, the distillation temperature is adjusted according to the different substrate resins, with a distillation temperature of 110℃-220℃ and a vacuum degree of 1-30 Pa.

[0017] This invention provides a method for preparing electronic-grade epoxy resin, which has the following beneficial effects: This invention precisely measures and uniformly mixes a dechlorinating agent with epoxy resin, then reacts it under nitrogen protection at a controlled temperature. This effectively removes low-boiling-point substances and chlorine-containing impurities. Continuous molecular distillation further separates the target resin with low total chlorine content, significantly reducing the total chlorine content in the epoxy resin. This preparation method not only improves the electrical insulation, heat resistance, and cured mechanical properties of electronic-grade epoxy resin, but also has broad applicability to various types of epoxy resins. Furthermore, it is simple to operate and cost-effective, solving the problems of complex processes, high costs, and incomplete separation in traditional methods. In addition, ion chromatography is used to detect the total chlorine in the product, ensuring that the product quality meets electronic-grade standards, providing the electronics industry with high-performance and reliable epoxy resin materials. Attached Figure Description

[0018] Figure 1 This is a schematic flowchart of the preparation method of electronic grade epoxy resin according to the present invention; Figure 2 This is a statistical chart of experimental data for a method of preparing electronic-grade epoxy resin according to the present invention; Figure 3 This is a schematic diagram of the prior art reaction of a method for preparing an electronic-grade epoxy resin according to the present invention. Detailed Implementation

[0019] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0020] Example 1: 680.0 g of bisphenol A diglycidyl ether resin with a total chlorine content of 1600 ppm was added to a three-necked flask, along with 2.8 g of MS51 dechlorinating agent (0.4% of the total resin mass). The mixture was heated to 110-140℃ under nitrogen protection and reacted for 3-6 hours. During the reaction, the dechlorinating agent reacted with chlorine-containing impurities in the resin, generating low-boiling-point substances, which were collected by condensation. After the reaction was deemed satisfactory, the material was transferred to a molecular distillation apparatus while still hot, and distilled at 160-200℃ under a vacuum of 10-30 Pa. After distillation, the low-total-chlorine resin was collected as a distillation product in the light component collection tank of the molecular distillation apparatus, while the chlorine-containing polymer impurities were collected as residue in the heavy component collection tank. The low-total-chlorine resin product obtained after distillation was collected and tested for total chlorine, with a result of 321 ppm. The residue was disposed of as hazardous waste.

[0021] Example 2: 700.0 g of bisphenol F diglycidyl ether resin with a total chlorine content of 2000 ppm was added to a three-necked flask, along with 4.2 g of MS51 dechlorinating agent (0.6% of the total resin mass). The mixture was heated to 110-140℃ under nitrogen protection and reacted for 3-6 hours. After the reaction was complete, the hot material was transferred to a molecular distillation apparatus for distillation separation at 160-200℃ and a vacuum of 10-30 Pa. The low-total-chlorine resin product obtained after distillation was collected and analyzed for total chlorine; the result was 372 ppm.

[0022] Example 3: 630g of 2,6-diallylphenyl glycidyl ether resin with a total chlorine content of 1800ppm was added to a three-necked flask, along with 5.1g of MS51 dechlorinating agent (0.8% of the total resin mass). The mixture was heated to 110-140℃ under nitrogen protection and reacted for 3-6 hours. After the reaction was complete, the hot material was transferred to a molecular distillation apparatus for distillation separation at 110-140℃ and a vacuum of 10-30 Pa. The low-total-chlorine resin product obtained after distillation was collected and analyzed for total chlorine; the result was 324ppm.

[0023] Example 4: 852.0 g of diglycidyl hexahydrophthalic acid resin with a total chlorine content of 9800 ppm was added to a three-necked flask, along with 19.5 g of MS51 dechlorinating agent (2.3% of the total resin mass). The mixture was heated to 110-140 °C under nitrogen protection and reacted for 3-6 hours. After the reaction was complete, the hot material was transferred to a molecular distillation apparatus for distillation separation at 160-200 °C and a vacuum of 10-30 Pa. The low-total-chlorine resin product obtained after distillation was collected and analyzed for total chlorine; the result was 1932 ppm.

[0024] Example 5: 1200.0 g of electronic-grade hydrogenated bisphenol A glycidyl ether with a total chlorine content of 1300 ppm was added to a three-necked flask, along with 12.0 g of MS51 dechlorinating agent (the amount of dechlorinating agent used was 1.0% of the total resin mass). The mixture was heated to 110-140℃ under nitrogen protection and reacted for 3-6 hours. After the reaction was complete, the hot material was transferred to a molecular distillation apparatus for distillation separation at 160-200℃ and a vacuum of 10-30 Pa. The low-total-chlorine resin product obtained after distillation was collected and tested for total chlorine; the result was 207 ppm.

[0025] Example 6: 900.0 g of hydrogenated bisphenol A glycidyl ether with a total chlorine content of 52375 ppm was added to a three-necked flask, along with 58.5 g of MS51 dechlorinating agent (6.5% of the total resin mass). The mixture was heated to 110-140℃ under nitrogen protection and reacted for 3-6 hours. After the reaction was complete, the hot material was transferred to a molecular distillation apparatus for distillation separation at 160-200℃ and a vacuum of 10-30 Pa. The low-total-chlorine resin product obtained after distillation was collected and analyzed for total chlorine content; the result was 5981 ppm.

[0026] Comparative Example 1: 650.0 g of bisphenol A diglycidyl ether resin with a total chlorine content of 1600 ppm was added to a molecular distillation apparatus and distilled at 160-200℃ and a vacuum of 10-30 Pa. The low-total-chlorine resin product obtained after distillation was collected and the total chlorine content was determined to be 851 ppm.

[0027] Compared with Example 1, the dechlorination effect was significantly different when molecular distillation was performed without adding a dechlorinating agent under the same conditions.

[0028] Comparative Example 2: 760.0 g of bisphenol F diglycidyl ether resin with a total chlorine content of 2000 ppm was added to a molecular distillation apparatus and distilled at 160-200℃ and a vacuum of 10-30 Pa. The low-total-chlorine resin product obtained after distillation was collected and the total chlorine content was determined to be 895 ppm.

[0029] Compared with Example 2, the dechlorination effect was significantly different when molecular distillation was performed without adding a dechlorinating agent under the same conditions.

[0030] in conclusion: 1. Effective Reduction of Total Chlorine Content: By precisely metering the dechlorinating agent and uniformly mixing it with epoxy resin, and then reacting it at a temperature under nitrogen protection, combined with molecular distillation technology, the total chlorine content in epoxy resin can be significantly reduced. Examples 1-6 reduced the total chlorine content from 1600ppm, 2000ppm, 1800ppm, 9800ppm, 1300ppm, and 52375ppm to 321ppm, 372ppm, 324ppm, 1932ppm, 207ppm, and 5981ppm, respectively, demonstrating the effectiveness of this method.

[0031] 2. Optimization of dechlorination agent dosage: The dosage of dechlorination agent has a significant impact on the reduction of total chlorine. In the examples, when the total chlorine is between 1000-10000 ppm, the preferred dosage of dechlorination agent is 0.2%-2.5% of the total resin mass; when the total chlorine is between 10000-55000 ppm, the preferred dosage is 2.5%-7.5%.

[0032] 3. Control of reaction temperature and time: Controlling the reaction temperature and time is equally important for reducing the total chlorine content. In the examples, the preferred reaction temperature is 100-140℃, and the reaction time is 3-6 hours, which can effectively promote the reaction between the dechlorinating agent and chlorine-containing impurities, generating low-boiling substances that are then collected by condensation.

[0033] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A method for preparing electronic-grade epoxy resin, applicable to a series of specific types of epoxy resins, including glycidyl ether and glycidyl ester epoxy resins, characterized in that, Includes the following steps: S1. Raw material preparation and mixing: Based on the detection data of total chlorine in epoxy resin, prepare the corresponding amount of dechlorinating agent, and mix the epoxy resin and dechlorinating agent evenly. S2, Heating reaction: The mixed materials are heated under nitrogen protection, while low-boiling substances are removed; S3. Molecular distillation separation: After the reaction is completed, the material is transferred to a molecular distillation device while it is still hot, and continuous distillation is performed to obtain the target resin with low total chlorine. Chlorine-containing polymer impurities are removed from the system in the form of residues.

2. The method for preparing an electronic-grade epoxy resin according to claim 1, characterized in that, In step S1, the dechlorination agent is selected from high molecular weight siloxanes, including but not limited to MS51, MS56, MS57, MS56S, and ethyl silicate 40, among which MS51 is preferred.

3. The method for preparing an electronic-grade epoxy resin according to claim 2, characterized in that, In step S1, the amount of dechlorinating agent used is determined according to the total chlorine content in the resin. When the total chlorine content is 1000-10000 ppm, the preferred amount used is 0.2%-2.5% of the total resin mass; when the total chlorine content is 10000-55000 ppm, the preferred amount used is 2.5%-7.5%.

4. The method for preparing an electronic-grade epoxy resin according to claim 1, characterized in that, In step S2, the reaction temperature is 60-160℃, preferably 100-140℃.

5. The method for preparing an electronic-grade epoxy resin according to claim 4, characterized in that, At the reaction temperature, the dechlorinating agent reacts with chlorine-containing impurities in the resin to generate low-boiling substances, which are then collected by condensation.

6. The method for preparing an electronic-grade epoxy resin according to claim 5, characterized in that, In step S2, the reaction equation using bisphenol A diglycidyl ether resin is illustrated below: R is either a chlorine-containing impurity produced in the reaction or a methyl group.

7. The method for preparing an electronic-grade epoxy resin according to claim 1, characterized in that, In step S3, impurities are separated by vacuum distillation. After distillation, the low total chlorine resin exists as a distillation product in the light component collection tank of the molecular distillation equipment, while the chlorine-containing polymer impurities exist as residues in the heavy component collection tank of the molecular distillation equipment.

8. The method for preparing an electronic-grade epoxy resin according to claim 1, characterized in that, In step S3, the distillation temperature is adjusted according to the different substrate resins, with a distillation temperature of 110℃-200℃ and a vacuum degree of 1-30 Pa.

9. The method for preparing an electronic-grade epoxy resin according to claim 1, characterized in that, It also includes the following steps: S4. Product collection and testing: Collect the low total chlorine resin product obtained after distillation and test the total chlorine content of the product.

10. The method for preparing an electronic-grade epoxy resin according to claim 9, characterized in that, The total chlorine was detected using ion chromatography.

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