A method for fractionally preparing a phenol aldehyde resin for photoresist

Abstract

The application discloses a kind of fractional preparation methods of phenol-formaldehyde resin for photoresist, phenol-formaldehyde resin synthesized with aldehyde, phenol as raw material, acid catalysis is dissolved in good solvent L and configured into phenol-formaldehyde resin solution;Phenol-formaldehyde resin solution is added in batches into poor solvent B, and solid is separated after each batch of poor solvent B is added, until no solid is precipitated, marked as the nth batch, and the solid separated in each batch is sequentially marked as S1, S2, …, S n‑1 ; The mixed solution obtained in the nth batch is subjected to fractional negative pressure distillation, and solid is further precipitated with the continuous extraction of good solvent L and poor solvent B, and the solid obtained after separation in each batch is sequentially marked as S n , S n+1 , S n+2 ……. By controlling the ratio of good solvent and poor solvent, the application realizes the continuous fractionalization of phenol-formaldehyde resin in the full molecular weight range and the controllable freedom of narrow and wide molecular weight distribution, avoids high-volatility toxic solvents, simplifies the fractional process, reduces costs, improves separation efficiency, and is conducive to industrialization.

Description

Technical Field

[0001] This invention belongs to the field of phenolic condensate purification and fractionation technology, specifically relating to a fractionation preparation method for phenolic resins used in photoresists. Background Technology

[0002] With the continuous advancement of 5G commercialization, my country has become the world's electronics manufacturing center. Industries such as printed circuit board (PCB), chip (IC) manufacturing, and flat panel display (FPD) have also experienced rapid development. The pace of electronic product updates and iterations is accelerating, greatly driving market demand for electronic materials. Technological innovation in electronic materials has become the driving force for industry development.

[0003] Phenolic resins, widely used in electronic materials, are increasingly applied in photoresists, molding compounds, copper-clad laminates, and photosensitive inks. In practical applications, the molecular weight distribution of phenolic resins has a direct and significant impact on their performance. Unrefined phenolic resins consist of unpolymerized monomers, dimers, and trimers, ranging from low molecular weight to high molecular weight with a high degree of polymerization, exhibiting a wide molecular weight distribution. This distribution directly affects various aspects of photoresist performance, including film-forming properties, exposure speed, imaging resolution, and aperture morphology. A narrower molecular weight distribution results in better heat resistance and stability, making the photoresist more stable at high temperatures and less prone to deformation or failure. Furthermore, a narrow molecular weight distribution improves photoresist resolution, enabling precise printing of fine patterns. The research results show that the presence of excessive low molecular weight phenolic resin in the product will greatly reduce its glass transition temperature, while the lack of low molecular weight phenolic resin may lead to problems such as excessively long development time in practical applications. Therefore, having a reasonable molecular weight distribution range, improving the utilization efficiency of phenolic resin, and reducing its application cost are technical issues that urgently need to be solved and standardized in the preparation process of phenolic resin.

[0004] From the perspective of phenolic resin synthesis, its molecular weight and distribution width can be comprehensively controlled by selecting appropriate formaldehyde / phenol monomer ratios, catalyst types and amounts, reaction temperature, reaction time, and other process parameters. However, in the actual synthesis of phenolic resin, the combined influence of numerous factors makes it difficult and cumbersome to synthesize phenolic resin products with a narrow molecular weight distribution in a single step. Patent CN115975137A utilizes a controlled polymerization method to directly introduce graded low-molecular-weight phenolic resin into a third polymer for modification, grafting a certain amount of poly(p-hydroxystyrene) polymer, and then remixing it with the high-molecular-weight fraction to achieve molecular weight control of the phenolic resin, thereby improving the heat resistance and etching resistance of the phenolic resin.

[0005] In Japanese Patent Application Publication No. 02-060915, No. 2008-050513, and CN116981708A, methods for separating low molecular weight components from phenolic resins are proposed from a molecular fractionation perspective. Japanese Patent Application Publication No. 02-060915 removes free monomers and low molecular weight impurities from the resin solution by adding water-soluble alcohol and water to the resin solution containing linear phenolic resin. Patent No. 2008-050513 utilizes a solvent fractionation method based on unsuitable and suitable solvents relative to the resin to remove oligomers from linear phenolic resins. It also proposes maintaining the reaction system temperature at 170-250°C while adding low-boiling-point compounds with lower boiling points than the reaction temperature to remove low molecular weight components from the linear phenolic resin. Both of the aforementioned disclosed technologies require the use of large quantities of methanol or acetone relative to the resin solution as good or bad solvents, with usage amounts reaching 1450 to 1653 times the mass of the resin solution. This results in high solvent consumption and high usage and processing costs. Furthermore, the solvents methanol and acetone used are highly volatile and pose significant physicochemical hazards and health risks. Patent CN116981708A, based on factors such as the polarity and dispersion forces of molecules with different molecular weights in the phenolic resin solution, utilizes a weighted average mathematical model of the SP values ​​from the Fedors method to calculate and predict the solubility of each substance in solvents A and B for solvent fractionation of phenolic resin. Solvent B is mixed with the resin solution obtained by dissolving the phenolic resin in solvent A, and the low molecular weight components of the phenolic resin are extracted into solvent B, thereby removing oligomer impurities from the phenolic resin. The molecular weight grading of phenolic resin mentioned in the above patents is limited to the separation and removal of impurity components such as free phenol monomers, dimers and trimers in phenolic resins. It can change the overall molecular weight distribution width of phenolic resins to a certain extent, but it is still far from meeting the requirements of practical applications. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a method for the graded preparation of phenolic resin for photoresists. By controlling the flow rate of the continuously added undesirable solvent into the system, the ratio of good to undesirable solvents in the system is adjusted, thereby achieving the graded preparation of phenolic resin from large to small molecular weight and realizing the purpose of adjusting the molecular weight distribution width. This method avoids the use of highly volatile solvents such as acetone and methanol, simplifies the phenolic resin grading process, reduces separation costs, improves separation efficiency, raw material utilization, and operational safety.

[0007] This invention is achieved through the following technical solution: A method for graded preparation of phenolic resin for photoresist includes the following steps: (1) Dissolve the phenolic resin synthesized from aldehydes and phenols as raw materials and acid catalysis in a good solvent L to prepare a phenolic resin solution; (2) Add undesirable solvent B to the phenolic resin solution in step (1) in batches. After adding undesirable solvent B to each batch, separate the solid until no solid precipitates. This batch is recorded as the nth batch. The solids separated in each batch are sequentially recorded as S1, S2, ..., S n-1 ; (3) The mixed solution obtained in the nth batch is subjected to batch-by-batch negative pressure distillation. As the good solvent L and the bad solvent B are continuously extracted, solids are further precipitated. The solids obtained in each batch after separation are recorded as S. n S n+1 S n+2 ...

[0008] Further, the good solvent L in step (1) is one of ethanol, isopropanol and low carbon ester; the bad solvent B in step (2) is one of water, n-hexane and cyclohexane.

[0009] Further, the good solvent L in step (1) is ethanol or ethyl acetate; the bad solvent B in step (2) is water.

[0010] Furthermore, the concentration of the phenolic resin solution in step (1) is 5~20%.

[0011] Furthermore, the concentration of the phenolic resin solution in step (1) is 12-17%.

[0012] Furthermore, the temperature of the negative pressure distillation in step (3) is 30~100℃.

[0013] Furthermore, the temperature of the negative pressure distillation in step (3) is 50~90℃.

[0014] Furthermore, the stirring speed in steps (1) to (3) is 800 to 1200 r / min.

[0015] Furthermore, the value of n ranges from 3 to 10.

[0016] Furthermore, the value of n ranges from 3 to 7.

[0017] In this invention, the amounts of good solvent L and bad solvent B used in the N batch grading can be selected and controlled according to the actual molecular weight distribution range required by the phenolic resin, making it easy to achieve controllable and adjustable overall molecular weight of the phenolic resin. Each grade of phenolic resin can be further graded by repeating steps (1) to (3) as needed to obtain a product with a more suitable molecular weight distribution width.

[0018] The beneficial effects achieved by this invention are as follows: This invention regulates the ratio of good to bad solvents in the system by controlling the flow rate of the continuous addition of bad solvents, enabling continuous grading of phenolic resins across the entire molecular weight range and allowing for a narrow and wide controllable molecular weight distribution. Furthermore, it avoids the use of highly volatile and toxic solvents such as acetone and methanol, simplifying the phenolic resin grading process, reducing separation costs, improving separation efficiency, raw material utilization, and operational safety, thus facilitating industrial application. Attached Figure Description

[0019] Figure 1 The chromatogram of phenolic resin GPC before fractionation is shown. Figure 2 The chromatogram of phenolic resin S1GPC in Example 2 is shown below. Figure 3 The chromatogram of phenolic resin S2GPC in Example 2 is shown below. Figure 4 The chromatogram of phenolic resin S3GPC in Example 2 is shown below. Figure 5 The chromatogram of phenolic resin S4GPC in Example 2 is shown below. Figure 6 The chromatogram of phenolic resin S5GPC in Example 2 is shown below. Figure 7 The chromatogram of phenolic resin S6GPC in Example 2 is shown. Detailed Implementation

[0020] The technical solutions involved in this patent will be described in full and detail below. The examples described are only a part of the embodiments of the present invention, and not all of them. Other embodiments based on the embodiments of the present invention, without any inventive adjustment to the design concept, are all within the protection scope of the present invention.

[0021] The GPC chromatograms of phenolic resins synthesized from aldehydes and phenols using acid catalysis in the following examples and comparative examples are shown below. Figure 1 As shown, its weight-average molecular weight Mw is 45267, and its molecular weight distribution width PDI is 12.840. Example 1

[0022] In Example 1, the reactors are connected in series. Each reactor contains a stirring device. Each reactor is connected to the next reactor via a solid-liquid separation device. The liquid (filtrate) separated by the solid-liquid separation device enters the next reactor, as detailed below: (1) At 25°C, in a primary reaction vessel, 1000g of phenolic resin was dissolved in anhydrous ethanol (a good solvent) to prepare a phenolic resin solution with a mass concentration of 15%. (2) Control the stirring speed to 1000 r / min, slowly add 800 g of ultrapure water (poor solvent) to the phenolic resin solution in step (1), filter the precipitate under negative pressure and dry to obtain 365.31 g of solid, which is recorded as S1. The molecular weight distribution width is recorded as PDI1=3.043, Mw: 251780. The filtrate is pumped into the secondary reaction vessel by a transfer pump. (3) Continue to add 800g of ultrapure water to the above secondary reaction vessel, and solid will precipitate again. After negative pressure filtration and drying, 147.24g of solid is obtained, which is recorded as S2. The molecular weight distribution width is recorded as PDI2=4.506, Mw:42298. The filtrate is pumped into the tertiary reaction vessel, and 800g of ultrapure water is added again. Solid will precipitate. After negative pressure filtration and drying, 108.37g of solid is obtained, which is recorded as S3. The molecular weight distribution width is recorded as PDI3=3.055, Mw:28966. (4) The filtrate obtained after three classifications was distilled under negative pressure at a gradient temperature of 8℃ / h from 40℃ to 70℃. With ethanol / water collected at a rate of 2000g / time, different grades of low molecular weight phenolic resin were further precipitated. The resins were filtered and dried to obtain solids S4=108.24g, S5=102.37g, and S6=87.61g, respectively. The molecular weight distribution widths were recorded as PDI4=2.313 (Mw: 7035), PDI5=2.927 (Mw: 4964), and PDI6=2.928 (Mw: 1763). Example 2

[0023] (1) At 25°C, in a primary reaction vessel, 1000g of phenolic resin was dissolved in isopropanol (a good solvent) to prepare a phenolic resin solution with a mass percentage concentration of 15%. (2) Control the stirring speed to 1000 r / min, slowly add 500 g of ultrapure water (poor solvent) to the phenolic resin solution in step (1), filter the precipitate under negative pressure and dry to obtain 278.24 g of solid, which is recorded as S1. Its GPC chromatogram is shown in the figure. Figure 2 The molecular weight distribution width is denoted as PDI1=5.983, Mw: 231610, and the filtrate is pumped into the secondary reaction vessel; (3) Add 500g of ultrapure water to the secondary reactor. Solid precipitates again. After negative pressure filtration and drying, 245.47g of solid is obtained, denoted as S2. GPC chromatogram is shown below. Figure 3 The molecular weight distribution width was denoted as PDI2 = 5.5063, Mw: 42213; the filtrate was pumped into a three-stage reactor, and 500g of ultrapure water was added. A solid precipitated, which was then filtered under negative pressure and dried to obtain 95.83g of solid, denoted as S3. GPC chromatogram results are shown below. Figure 4 The molecular weight distribution width is denoted as PDI3=4.155, Mw: 19455; (4) The filtrate obtained from the above three-stage reaction vessel was distilled under negative pressure at a gradient temperature of 50℃~80℃ at 10℃ / h, with isopropanol / water being collected at a rate of 2000g / time, further precipitating different grades of low molecular weight phenolic resin. These were then filtered and dried to obtain solids S4=95.37g, S5=83.25g, and S6=75.38g, respectively. GPC chromatograms showed the results as follows: Figure 5 , Figure 6 and Figure 7 The molecular weight distribution widths are denoted as PDI4=2.448 (Mw: 4033), PDI5=2.314 (Mw: 3069), and PDI6=1.349 (Mw: 561), respectively. Example 3

[0024] 245g of phenolic resin obtained from the two-stage reaction vessel separation in Example 2 was prepared into a 12% phenolic resin ethanol solution. 300g of ultrapure water (a poor solvent) was added at each stage, and the stirring speed was controlled at 1200 r / min. The solution was then subjected to three consecutive stages of separation as described in Example 1. The phenolic resin obtained from each stage was filtered, dried, and analyzed. Specific data are shown in Table 1. Table 1 .

[0025] Comparative Example 1 At 25°C, 1000g of phenolic resin was dissolved in anhydrous ethanol (a good solvent) in a primary reactor to prepare a phenolic resin solution with a mass concentration of 25%. For each stage, a poor solvent was added according to the good solvent / poor solvent ratio in Example 1. All other operations were the same as described in Example 1. After three consecutive stages of grading, the phenolic resins obtained from each stage were filtered, dried, and analyzed. Specific data are shown in Table 2. Table 2 .

[0026] Comparative Example 2 The stirring speed was controlled at 300 r / min throughout the process, and other operating procedures and conditions were the same as in Example 2. After three consecutive stages of grading, the phenolic resins obtained from each stage were filtered, dried, and analyzed. The specific comparison data with Example 2 are shown in Table 3. Table 3 .

[0027] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for graded preparation of phenolic resin for photoresist, characterized in that, Includes the following steps: (1) Dissolve the phenolic resin synthesized from aldehydes and phenols as raw materials and catalyzed by acid in a good solvent L to prepare a phenolic resin solution; (2) Add undesirable solvent B to the phenolic resin solution in step (1) in batches. After adding undesirable solvent B to each batch, separate the solid until no solid precipitates. This batch is recorded as the nth batch. The solids separated in each batch are sequentially recorded as S1, S2, ..., S n-1 ; (3) The mixed solution obtained in the nth batch is subjected to batch-by-batch negative pressure distillation. As the good solvent L and the bad solvent B are continuously extracted, solids are further precipitated. The solids obtained in each batch after separation are recorded as S. n S n+1 S n+2 ...

2. The method for graded preparation of phenolic resin for photoresist according to claim 1, characterized in that, In step (1), the good solvent L is one of ethanol, isopropanol and low carbon ester; in step (2), the bad solvent B is one of water, n-hexane and cyclohexane.

3. The method for graded preparation of phenolic resin for photoresist according to claim 2, characterized in that, In step (1), the good solvent L is ethanol or ethyl acetate; in step (2), the bad solvent B is water.

4. The method for graded preparation of phenolic resin for photoresist according to claim 1, characterized in that, The concentration of the phenolic resin solution in step (1) is 5~20%.

5. The method for graded preparation of phenolic resin for photoresist according to claim 4, characterized in that, The concentration of the phenolic resin solution in step (1) is 12-17%.

6. The method for graded preparation of phenolic resin for photoresist according to claim 1, characterized in that, The temperature of the negative pressure distillation in step (3) is 30~100℃.

7. The method for graded preparation of phenolic resin for photoresist according to claim 6, characterized in that, The temperature of the negative pressure distillation in step (3) is 50~90℃.

8. The method for graded preparation of phenolic resin for photoresist according to claim 1, characterized in that, The stirring speed in steps (1) to (3) is 800 to 1200 r / min.

9. The method for graded preparation of phenolic resin for photoresist according to claim 1, characterized in that, The value of n ranges from 3 to 10.

10. The method for graded preparation of phenolic resin for photoresist according to claim 9, characterized in that, The value of n ranges from 3 to 7.

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