Application method of acrylic modified tgic additive for uv photosensitive solder resist ink

Abstract

The application provides an application method of an acrylic modified TGIC additive for UV photosensitive solder resist ink. The modified TGIC additive is obtained by the ring-opening reaction of triepoxy glycidyl isocyanurate (TGIC) and an active monomer containing an unsaturated double bond, and then esterification reaction with an unsaturated anhydride. The modified TGIC additive has good solubility in the commonly used solvent of the ink, ethyl ether acetate or polytoluene. The modified TGIC additive can easily form a dispersed phase by blending with a photocuring resin matrix, so that the UV photosensitive solder resist ink with high heat resistance and high mechanical properties is prepared, and the UV photosensitive solder resist ink has high developability and can be directly applied to the production process of the existing UV photosensitive solder resist ink. Meanwhile, the addition amount of the solvent in the UV photosensitive solder resist ink can be effectively reduced, and the prepared product does not have problems such as too high viscosity and poor flowability caused by the reduction of the addition amount of the solvent.

Description

[0001] This application is a divisional application. The original application number is 202211574599.0, the application date is December 8, 2022, and the invention title is: A modified TGIC additive for UV photosensitive solder resist ink and its preparation method. Technical Field

[0002] This invention relates to the field of UV photosensitive solder resist ink technology, specifically to a modified TGIC additive for UV photosensitive solder resist ink and its preparation method. Background Technology

[0003] A printed circuit board (PCB) is a substrate for mounting and connecting components in modern electrical appliances and is an important basic assembly component in the electronics industry.

[0004] Among them, photocurable solder resist ink is one of the key materials of printed circuit boards (PCBs). It refers to the protective coating that covers the copper lines of printed circuits to prevent circuit corrosion and breakage, prevent short circuits between lines caused by multiple solder joints, adjust the amount of solder adhesion, reduce copper dissolution and contamination in the solder joint, save solder, reduce instrument weight, increase wiring density, avoid cold solder joints, and improve inspection speed.

[0005] In the PCB ink industry, resins are required to have both photocurability and developability. Therefore, resins often contain a certain number of unsaturated double bonds and a certain number of carboxyl groups to balance photocurability and developability.

[0006] Traditional photocurable solder resist inks typically consist of polymeric monomers, photoinitiators, and polymerization inhibitors. Currently, the most commonly used photocurable solder resist inks generally include a combination of a photopolymerization initiator and a photocurable / thermocurable resin containing carboxyl groups. Among these, the photocurable / thermocurable resin is generally epoxy acrylic resin. While it possesses advantages such as good photocurability, developability, and mechanical properties, the cross-linking density of the cured film is low, resulting in poor heat resistance. It is prone to blistering or oil peeling during soldering, failing to meet the requirements of high-precision circuit boards. Furthermore, its low resolution makes it unsuitable for manufacturing high-precision circuit boards, hindering the application of solder resist inks in high-frequency communication development.

[0007] In current production of UV-curable solder resist inks, epoxy resin oligomers are often used as the UV-curable resin matrix. Based on the inventor's long-term research experience and review of existing technical literature, mainstream reports primarily focus on modifying the resin matrix to obtain solder resist inks with excellent performance. However, since the resin matrix is ​​the most important component of UV-curable solder resist inks, modifying it usually leads to negative factors such as increased production process complexity and higher costs. In particular, while improving the mechanical properties of the coating film, it often results in a decrease in developability. Therefore, modification technologies targeting the resin matrix are often difficult to truly integrate into the production process.

[0008] Therefore, some researchers have improved coating performance by mixing multiple resin matrices. For example, Chinese invention patent document CN104177993B discloses a UV-curable olefin-based polyester coating for ceramics, which uses a mixture of epoxy acrylate, triglycidyl isocyanate, polyurethane acrylate, and diethylene glycol diacrylate as a matrix to prepare the UV-curable olefin-based polyester coating. However, this process, due to the use of multiple resin matrices, significantly increases raw material costs in actual industrial applications. Furthermore, the patent does not consider the compatibility issues arising from mixing multiple resin matrices, which can significantly affect the difficulty of processing and the quality of the product.

[0009] Therefore, it is necessary to develop photocurable solder resist inks that combine high developability and excellent mechanical properties from a new perspective. Summary of the Invention

[0010] In view of the problems raised by the prior art, the present invention provides a modified TGIC additive for UV photosensitive solder resist ink and its preparation method. The preparation method firstly opens the epoxy group in TGIC by unsaturated acid such as acrylic acid to introduce a certain number of double bonds. The secondary hydroxyl group generated by the reaction then reacts completely with unsaturated acid anhydride to obtain a TGIC-based photocurable compound that has both photocurability and developability.

[0011] To achieve the above objectives, the present invention employs a technical solution consisting of the following technical measures.

[0012] In one aspect, the present invention provides a modified TGIC additive for UV photosensitive solder resist ink, which is obtained by first performing a ring-opening reaction between triglycidyl isocyanurate (TGIC) and an active monomer containing unsaturated double bonds, and then performing an esterification reaction with unsaturated acid anhydrides.

[0013] The addition of the unsaturated double-bonded active monomer is carried out in a molar ratio of (1-1.2):1 with the epoxy group of TGIC, and the addition of the unsaturated acid anhydride is carried out in a molar ratio of (1-1.2):1 with the epoxy group of TGIC.

[0014] The active monomer containing unsaturated double bonds is a monomer whose molecular structure contains a carboxyl group and at least one alkenyl group that can react with an epoxy group.

[0015] The main inventive point of this invention is that by utilizing the special chemical structure of triglycidyl isocyanurate (TGIC), experimental results have been demonstrated that when TGIC is added to the process of UV photosensitive solder resist ink and blended with an epoxy resin matrix, the resulting UV photosensitive solder resist ink can significantly improve the heat resistance and mechanical properties of the product while maintaining high developability.

[0016] Triglycidyl isocyanurate, abbreviated as TGIC, has a melting point of 95–98°C. It is a crystalline heterocyclic epoxy compound with three highly reactive epoxy groups that can undergo high-density cross-linking with the hydroxyl groups in polyester resins. The heterocycles are also very stable, exhibiting excellent heat resistance, weather resistance, light resistance, corrosion resistance, chemical resistance, and mechanical properties. Its chemical structural formula is as follows:

[0017]

[0018] However, TGIC, as a raw material, is currently priced relatively high in the market, typically 5 to 10 times that of epoxy resin matrix raw materials. Therefore, referring to the technical solution of Chinese invention patent document CN104177993B mentioned in the background art, using it as one of the various resin matrices would lead to a sharp increase in product costs and a loss of market competitiveness.

[0019] Based on this, the inventors of this invention verified through experiments during the research and development process that when TGIC is used as an additive for UV photosensitive solder resist ink, that is, under the premise of adding a small amount (<5wt%), the prepared UV photosensitive solder resist ink can significantly improve its heat resistance and mechanical properties. This not only ensures cost but also significantly improves product performance.

[0020] However, during the sample processing, it was discovered that TGIC, being a white crystalline solid at room temperature, is insoluble in commonly used ink solvents such as diethyl ether acetate or toluene at room temperature. Furthermore, because it needs to be blended with a UV-curable resin matrix, and the resin matrix contains numerous unsaturated double bonds, it cannot be effectively dispersed by heating above the melting point of TGIC. Through research and development, it was found that TGIC can only be forcibly dispersed in the resin matrix through mechanochemical methods such as grinding, while simultaneously increasing the proportion of commonly used ink solvents by at least 5 wt% to meet the requirement of sufficient dispersion. However, this necessitates adding new processing steps to the existing production line and extending the product manufacturing cycle.

[0021] Furthermore, through long-term production, process development, and market research, the inventors discovered that commonly used additives in UV photosensitive solder resist inks also suffer from dispersibility issues with commonly used ink solvents. Given that UV photosensitive solder resist inks represent a relatively mature process system, those skilled in the art typically use a fixed saturation addition amount for the solvent to avoid product quality problems when changing additives in UV photosensitive solder resist inks. This fixed saturation addition amount is typically 25wt% to 30wt%.

[0022] In view of the above research findings and problems, the inventors further proposed to modify TGIC. They found that by opening the epoxy groups in TGIC with unsaturated acids such as acrylic acid and introducing a certain number of double bonds, the secondary hydroxyl groups generated in the reaction can then react completely with unsaturated acid anhydrides. The resulting modified TGIC additive has good solubility in commonly used ink solvents such as diethyl ether acetate or toluene. It can be easily blended with a photocurable resin matrix to form a dispersed phase, thereby preparing a UV photosensitive solder resist ink with high heat resistance and high mechanical properties, while also having high developability. It can be directly applied to the production process of existing UV photosensitive solder resist inks.

[0023] Furthermore, in the process development, the inventors were pleasantly surprised to find that by modifying TGIC and using it as an additive for UV photosensitive solder resist inks, the proportion of commonly used ink solvents (ethyl ether acetate, polytoluene) added in the process can be reduced. The amount of solvent added can be reduced from 25wt% to 10wt%~15wt%. At the same time, the prepared product did not have problems such as excessive viscosity and poor flowability that may be caused by the reduction of solvent addition, and its performance was significantly better than similar products with conventional UV photosensitive solder resist ink additives.

[0024] To better illustrate the principles of this invention, one technical solution will be used as an example for explanation:

[0025] When the unsaturated anhydride is selected as tetrahydrophthalic anhydride, and when the unsaturated acid is selected as acrylic acid, the reaction route is as follows:

[0026]

[0027] When the unsaturated anhydride is chosen as itaconic anhydride, and when the unsaturated acid is chosen as methacrylic acid, the reaction route is as follows:

[0028]

[0029] In this article, the “triglycidyl isocyanurate (TGIC)” can be commercially available or self-made, and the purity requirement is usually chemical raw material grade.

[0030] In one technical solution, the active monomer containing unsaturated double bonds is a monomer whose molecular structure contains a carboxyl group and at least one alkenyl group that can react with epoxy groups. To minimize steric hindrance in the reaction system, the monomer has a carbon number of C3 to C20, and the carboxyl group and at least one alkenyl group that can react with epoxy groups can be selected as acryloyl or methacryloyl. Furthermore, to reduce process costs, acrylic acid or methacrylic acid, commonly used in the field of UV photosensitive solder resist inks, can be selected.

[0031] In one technical solution, the unsaturated anhydride may be selected from unsaturated anhydrides commonly used in the field of UV photosensitive solder resist inks, such as at least one of tetrahydrophthalic anhydride, itaconic anhydride, maleic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

[0032] This paper presents a reaction route in which triglycidyl isocyanurate (TGIC) undergoes a ring-opening reaction with an active monomer containing an unsaturated double bond, followed by an esterification reaction with an unsaturated acid anhydride. It should be noted that those skilled in the art can derive the specific preparation steps based on the above reaction route; therefore, the technical solutions provided below in this invention do not imply the sole designation or limitation of the preparation method of this invention.

[0033] On the other hand, to better illustrate the present invention, and to provide a method for preparing a modified TGIC additive for UV photosensitive solder resist ink, the method includes the following steps:

[0034] (1) Under an inert gas atmosphere, preheat the solvent to 100-120°C, add TGIC and dissolve it, cool down to 60-80°C and add an active monomer containing unsaturated double bonds, then heat up to 100-120°C, add a cyclic ester ring-opening polymerization catalyst, then adjust the temperature to 110-130°C and stir the reaction for 7-12 hours until the acid value of the reaction solution is less than 3 mg KOH / g and the epoxy equivalent is less than 40, then a TGIC resin solution containing unsaturated double bonds is obtained.

[0035] (2) Cool the TGIC resin solution containing unsaturated double bonds obtained in step (1) to 70-80°C, then add unsaturated acid anhydride and polymerization inhibitor and mix. Continue to stir and react at 90-100°C for 3-7 hours to obtain the modified TGIC additive; wherein, the amount of polymerization inhibitor added is 0.4-2.5 wt% of the TGIC resin solution in step (1).

[0036] In this article, the cyclic ester ring-opening polymerization catalyst mentioned in step (1) is a cyclic ester ring-opening polymerization catalyst commonly used in the field of epoxy resin ring-opening polymerization reaction. Those skilled in the art can select a suitable cyclic ester ring-opening polymerization catalyst according to actual needs.

[0037] In one technical solution, the cyclic ester ring-opening polymerization catalyst in step (1) is selected from one of triethylamine, triethanolamine, 4-dimethylaminopyridine, tetrabutylammonium bromide, tetramethylammonium chloride, N,N-dimethylbenzylamine and triphenylphosphine; the amount of cyclic ester ring-opening polymerization catalyst added is 0.2 to 1 wt% of the TGIC.

[0038] In this document, the solvent used in step (1) is a conventional solvent in this technical field, such as a conventional solvent for inks.

[0039] In one technical solution, the solvent selected in step (1) includes at least one of the following: divalent ester high-boiling-point environmentally friendly solvents, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, propylene glycol methyl ether propionate, dipropylene glycol methyl ether, propylene glycol methyl ether, trimethylbenzene, and tetramethylbenzene; in step (1), the solvent mass: TGIC mass = (0.5~1.5):1.

[0040] In this paper, the polymerization inhibitor mentioned in step (2) is a conventional polymerization inhibitor in this technical field, which can be a conventional polymerization inhibitor for inks.

[0041] In one technical solution, the polymerization inhibitor in step (2) is selected from at least one of hydroquinone, o-methylhydroquinone, p-hydroxyanisole, p-benzoquinone, and 2,6-di-tert-butyl-4-methylphenol. Preferably, the polymerization inhibitor added in both steps is the same polymerization inhibitor.

[0042] In this document, the stirring reaction described in steps (1) and (2) is a stirring reaction conventionally used in the art, including magnetic stirring or mechanical stirring. Those skilled in the art can choose a suitable stirring reaction method according to the production scale or current process conditions. In one technical solution, the stirring reaction can be carried out at a stirring rate of 100 to 300 rpm.

[0043] Based on the above findings, in another aspect, the present invention provides a method for applying the modified TGIC additive for UV photosensitive solder resist ink, which involves adding the modified TGIC additive to a resin matrix solution for dissolution and blending, wherein the amount of the modified TGIC additive added is 0.2 to 3 wt% of the resin matrix.

[0044] In this article, the resin matrix solution refers to the state in which the resin matrix is ​​dissolved in a solvent and is in the state before the ring-opening polymerization reaction.

[0045] In a preferred embodiment, the resin matrix solution is prepared by dissolving the resin matrix in a solvent, and the amount of solvent added is 10-15 wt% of the resin matrix. In contrast, in current mature UV photosensitive solder resist ink processes, the amount of solvent added is typically 25-30 wt% of the resin matrix.

[0046] In one technical solution, the resin matrix is ​​the resin matrix commonly used in UV photosensitive solder resist inks, preferably an epoxy resin matrix, such as any one of bisphenol A type epoxy resin, phenolic epoxy resin, o-cresol phenolic epoxy resin, p-tert-butylphenol phenolic epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, diglycidyl phthalate, tetrahydrophthalate diglycidyl phthalate, triglycidyl isocyanurate, and dicyclodiene epoxide.

[0047] In this paper, after the modified TGIC additive is dissolved and blended in the resin matrix solution, UV photosensitive solder resist ink can be prepared by referring to the existing technology or process route in the field of UV photosensitive solder resist ink preparation.

[0048] The present invention has the following beneficial effects:

[0049] 1. This invention provides a modified TGIC additive prepared by modifying TGIC, which has good solubility in commonly used ink solvents such as diethyl ether acetate or toluene. It can be easily mixed with a photocurable resin matrix to form a dispersed phase, thereby preparing a UV photosensitive solder resist ink with high heat resistance and high mechanical properties, and at the same time also has high developability. It can be directly applied to the production process of existing UV photosensitive solder resist inks.

[0050] 2. The modified TGIC additive provided by this invention has been experimentally verified to effectively reduce the amount of solvent required in UV photosensitive solder resist inks. At the same time, the prepared product does not exhibit problems such as excessively high viscosity and poor flowability that may be caused by the reduction in solvent addition. Moreover, its performance is significantly better than similar products with conventional UV photosensitive solder resist ink additives.

[0051] 3. The preparation process of this invention is simple, and the modified TGIC additive obtained can be applied to the UV photosensitive solder resist ink production process in the same way as conventional additives, without adding new processing steps, thus ensuring that the overall production efficiency remains unchanged.

[0052] 4. The UV photosensitive solder resist ink provided by this invention has excellent performance and is suitable for high-end equipment manufacturing.

[0053] Instruction manual illustrations

[0054] Figure 1 This is a photograph of the finished product of the modified TGIC additive prepared in Example 1 of this invention. The reagent appears yellow in the photograph.

[0055] Figure 2 The image shows the infrared spectrum of the modified TGIC auxiliary agent prepared in Example 1 of this invention. Interpretation of the spectrum confirms the successful synthesis of the target compound. Detailed Implementation

[0056] To further understand the present invention, preferred embodiments are described below with reference to examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims. Those skilled in the art can refer to the content of this document to appropriately improve the process parameters. In particular, it should be noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the scope of the present invention. The methods and applications of the present invention have been described through preferred embodiments, and those skilled in the art can obviously make modifications or appropriate changes and combinations to the methods and applications described herein without departing from the content, spirit and scope of the present invention to realize and apply the technology of the present invention. Although it is believed that those skilled in the art will fully understand the following terms, the following definitions are set forth to help illustrate the subject matter disclosed in the present invention.

[0057] In one aspect, the present invention provides a modified TGIC additive for UV photosensitive solder resist ink, which is obtained by first performing a ring-opening reaction between triglycidyl isocyanurate (TGIC) and an active monomer containing unsaturated double bonds, and then performing an esterification reaction with unsaturated acid anhydrides.

[0058] The addition of the unsaturated double-bonded active monomer is carried out in a molar ratio of (1-1.2):1 with the epoxy group of TGIC, and the addition of the unsaturated acid anhydride is carried out in a molar ratio of (1-1.2):1 with the epoxy group of TGIC.

[0059] The active monomer containing unsaturated double bonds is a monomer whose molecular structure contains a carboxyl group and at least one alkenyl group that can react with an epoxy group.

[0060] The main inventive point of this invention is that by utilizing the special chemical structure of triglycidyl isocyanurate (TGIC), experimental results have been demonstrated that when TGIC is added to the process of UV photosensitive solder resist ink and blended with an epoxy resin matrix, the resulting UV photosensitive solder resist ink can significantly improve the heat resistance and mechanical properties of the product while maintaining high developability.

[0061] Triglycidyl isocyanurate, abbreviated as TGIC, has a melting point of 95–98°C. It is a crystalline heterocyclic epoxy compound with three highly reactive epoxy groups that can undergo high-density cross-linking with the hydroxyl groups in polyester resins. The heterocycles are also very stable, exhibiting excellent heat resistance, weather resistance, light resistance, corrosion resistance, chemical resistance, and mechanical properties. Its chemical structural formula is as follows:

[0062]

[0063] However, TGIC, as a raw material, is currently priced relatively high in the market, typically 5 to 10 times that of epoxy resin matrix raw materials. Therefore, referring to the technical solution of Chinese invention patent document CN104177993B mentioned in the background art, using it as one of the various resin matrices would lead to a sharp increase in product costs and a loss of market competitiveness.

[0064] Based on this, the inventors of this invention verified through experiments during the research and development process that when TGIC is used as an additive for UV photosensitive solder resist ink, that is, under the premise of adding a small amount (<5wt%), the prepared UV photosensitive solder resist ink can significantly improve its heat resistance and mechanical properties. This not only ensures cost but also significantly improves product performance.

[0065] However, during the sample processing, it was discovered that TGIC, being a white crystalline solid at room temperature, is insoluble in commonly used ink solvents such as diethyl ether acetate or toluene at room temperature. Furthermore, because it needs to be blended with a UV-curable resin matrix, and the resin matrix contains numerous unsaturated double bonds, it cannot be effectively dispersed by heating above the melting point of TGIC. Through research and development, it was found that TGIC can only be forcibly dispersed in the resin matrix through mechanochemical methods such as grinding, while simultaneously increasing the proportion of commonly used ink solvents by at least 5 wt% to meet the requirement of sufficient dispersion. However, this necessitates adding new processing steps to the existing production line and extending the product manufacturing cycle.

[0066] Furthermore, through long-term production, process development, and market research, the inventors discovered that commonly used additives in UV photosensitive solder resist inks also suffer from dispersibility issues with commonly used ink solvents. Given that UV photosensitive solder resist inks represent a relatively mature process system, those skilled in the art typically use a fixed saturation addition amount for the solvent to avoid product quality problems when changing additives in UV photosensitive solder resist inks. This fixed saturation addition amount is typically 25wt% to 30wt%.

[0067] In view of the above research findings and problems, the inventors further proposed to modify TGIC. They found that by opening the epoxy groups in TGIC with unsaturated acids such as acrylic acid and introducing a certain number of double bonds, the secondary hydroxyl groups generated in the reaction can then react completely with unsaturated acid anhydrides. The resulting modified TGIC additive has good solubility in commonly used ink solvents such as diethyl ether acetate or toluene. It can be easily blended with a photocurable resin matrix to form a dispersed phase, thereby preparing a UV photosensitive solder resist ink with high heat resistance and high mechanical properties, while also having high developability. It can be directly applied to the production process of existing UV photosensitive solder resist inks.

[0068] Furthermore, in the process development, the inventors were pleasantly surprised to find that by modifying TGIC and using it as an additive for UV photosensitive solder resist inks, the proportion of commonly used ink solvents (ethyl ether acetate, polytoluene) added in the process can be reduced. The amount of solvent added can be reduced from 25wt% to 10wt%~15wt%. At the same time, the prepared product did not have problems such as excessive viscosity and poor flowability that may be caused by the reduction of solvent addition, and its performance was significantly better than similar products with conventional UV photosensitive solder resist ink additives.

[0069] To better illustrate the principles of this invention, one embodiment will be used as an example for explanation:

[0070] When the unsaturated anhydride is selected as tetrahydrophthalic anhydride, and when the unsaturated acid is selected as acrylic acid, the reaction route is as follows:

[0071]

[0072] When the unsaturated anhydride is chosen as itaconic anhydride, and when the unsaturated acid is chosen as methacrylic acid, the reaction route is as follows:

[0073]

[0074] In this article, the “triglycidyl isocyanurate (TGIC)” can be commercially available or self-made, and the purity requirement is usually chemical raw material grade.

[0075] In one embodiment, the unsaturated double-bond active monomer is a monomer whose molecular structure contains a carboxyl group and at least one alkenyl group that can react with an epoxy group. To minimize steric hindrance in the reaction system, the monomer has a carbon number of C3 to C20, for example, any one of C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, or C20; and the carboxyl group and at least one alkenyl group that can react with the epoxy group can be selected as acryloyl or methacryloyl. Furthermore, to reduce process costs, acrylic acid or methacrylic acid, commonly used in the field of UV photosensitive solder resist inks, can be selected.

[0076] In one embodiment, the unsaturated anhydride may be selected from unsaturated anhydrides commonly used in the field of UV photosensitive solder resist inks, such as at least one of tetrahydrophthalic anhydride, itaconic anhydride, maleic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

[0077] In one embodiment, the unsaturated double-bond active monomer is added in a molar ratio of (1 to 1.2):1 with the epoxy group of TGIC, for example, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, or any range or point value between them; the unsaturated anhydride is added in a molar ratio of (1 to 1.2):1 with the epoxy group of TGIC, for example, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, or any range or point value between them.

[0078] This paper presents a reaction route in which triglycidyl isocyanurate (TGIC) undergoes a ring-opening reaction with an active monomer containing an unsaturated double bond, followed by an esterification reaction with an unsaturated acid anhydride. It should be noted that those skilled in the art can derive the specific preparation steps based on the above reaction route; therefore, the technical solutions provided below in this invention do not imply the sole designation or limitation of the preparation method of this invention.

[0079] On the other hand, to better illustrate the present invention, and to provide a method for preparing a modified TGIC additive for UV photosensitive solder resist ink, the method includes the following steps:

[0080] (1) Under an inert gas atmosphere, preheat the solvent to 100-120°C, add TGIC and dissolve it, cool down to 60-80°C and add an active monomer containing unsaturated double bonds, then heat up to 100-120°C, add a cyclic ester ring-opening polymerization catalyst, then adjust the temperature to 110-130°C and stir the reaction for 7-12 hours until the acid value of the reaction solution is less than 3 mg KOH / g and the epoxy equivalent is less than 40, then a TGIC resin solution containing unsaturated double bonds is obtained.

[0081] (2) Cool the TGIC resin solution containing unsaturated double bonds obtained in step (1) to 70-80°C, then add unsaturated acid anhydride and polymerization inhibitor and mix. Continue to stir and react at 90-100°C for 3-7 hours to obtain the modified TGIC additive; wherein, the amount of polymerization inhibitor added is 0.4-2.5 wt% of the TGIC resin solution in step (1).

[0082] In this article, the cyclic ester ring-opening polymerization catalyst mentioned in step (1) is a cyclic ester ring-opening polymerization catalyst commonly used in the field of epoxy resin ring-opening polymerization reaction. Those skilled in the art can select a suitable cyclic ester ring-opening polymerization catalyst according to actual needs.

[0083] In one embodiment, the cyclic ester ring-opening polymerization catalyst in step (1) is one of triethylamine, triethanolamine, 4-dimethylaminopyridine, tetrabutylammonium bromide, tetramethylammonium chloride, N,N-dimethylbenzylamine, and triphenylphosphine; the amount of cyclic ester ring-opening polymerization catalyst added is 0.2 to 1 wt% of the TGIC, for example 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, or any range or point value between them.

[0084] In this document, the solvent used in step (1) is a conventional solvent in this technical field, such as a conventional solvent for inks.

[0085] In one embodiment, the solvent in step (1) is at least one of the following: divalent ester high-boiling-point environmentally friendly solvent, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, propylene glycol methyl ether propionate, dipropylene glycol methyl ether, propylene glycol methyl ether, trimethylbenzene, and tetramethylbenzene; in step (1), the solvent mass: TGIC mass = (0.5~1.5):1, for example 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, or any range or point value between them.

[0086] In this paper, the polymerization inhibitor mentioned in step (2) is a conventional polymerization inhibitor in this technical field, which can be a conventional polymerization inhibitor for inks.

[0087] In one embodiment, the polymerization inhibitor in step (2) is selected from at least one of hydroquinone, o-methylhydroquinone, p-hydroxyanisole, p-benzoquinone, and 2,6-di-tert-butyl-4-methylphenol. Preferably, the polymerization inhibitor added in both steps is the same polymerization inhibitor.

[0088] In this document, the stirring reaction described in steps (1) and (2) is a stirring reaction conventionally used in the art, including magnetic stirring or mechanical stirring. Those skilled in the art can choose a suitable stirring reaction method according to the production scale or current process conditions. In one embodiment, the stirring reaction can be carried out at a stirring rate of 100 to 300 rpm.

[0089] Based on the above findings, in another aspect, the present invention provides a method for applying the modified TGIC additive for UV photosensitive solder resist inks, which involves dissolving and blending the modified TGIC additive in a resin matrix solution. The amount of the modified TGIC additive added is 0.2 to 3 wt% of the resin matrix, for example, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2 wt%, 2.1 wt%, 2.2 wt%, 2.3 wt%, 2.4 wt%, 2.5 wt%, 2.6 wt%, 2.7 wt%, 2.8 wt%, 2.9 wt%, 3 wt%, or any range or point value between them.

[0090] In this article, the resin matrix solution refers to the state in which the resin matrix is ​​dissolved in a solvent and is in the state before the ring-opening polymerization reaction.

[0091] In one preferred embodiment, the resin matrix solution is a solution of the resin matrix dissolved in a solvent, and the amount of solvent added is 10-15 wt% of the resin matrix, for example, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, or any range or point value between them. In contrast, in current mature UV photosensitive solder resist ink processes, the amount of solvent added is typically 25-30 wt% of the resin matrix.

[0092] In one embodiment, the resin matrix is ​​a resin matrix commonly used in UV photosensitive solder resist inks, preferably an epoxy resin matrix, such as any one of bisphenol A type epoxy resin, phenolic epoxy resin, o-cresol phenolic epoxy resin, p-tert-butylphenol phenolic epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, diglycidyl phthalate, tetrahydrophthalate diglycidyl phthalate, triglycidyl isocyanurate, and dicyclodiene epoxide.

[0093] In this paper, after the modified TGIC additive is dissolved and blended in the resin matrix solution, UV photosensitive solder resist ink can be prepared by referring to the existing technology or process route in the field of UV photosensitive solder resist ink preparation.

[0094] The present application will be further explained in detail below with reference to embodiments. However, those skilled in the art should understand that these embodiments are provided for illustrative purposes only and are not intended to limit the present application.

[0095] Example

[0096] The embodiments of this application will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be construed as limiting the scope of this application. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Where the manufacturers of reagents or instruments are not specified, they are all commercially available conventional products. This application should not be construed as being limited to the specific embodiments described.

[0097] 1. Preparation method

[0098] Synthesis example 1:

[0099] (1) Under an inert gas atmosphere, trimethylbenzene was preheated to 105°C, TGIC was added and dissolved, the temperature was lowered to 80°C and acrylic acid was added, the temperature was raised to 110°C and triethylamine was added, the temperature was adjusted to 110°C and the reaction was stirred for 10 hours until the acid value of the reaction solution was less than 3 mg KOH / g and the epoxy equivalent was less than 40, thus obtaining a TGIC resin solution containing unsaturated double bonds; the amount of triethylamine added was 0.5 wt% of the TGIC, and the mass ratio of trimethylbenzene to TGIC was 1:1;

[0100] (2) Cool the TGIC resin solution containing unsaturated double bonds obtained in step (1) to 80°C, then add tetrahydrophthalic anhydride and hydroquinone and mix, and continue to stir and react at 95°C for 5 hours to obtain the modified TGIC additive; wherein, the amount of the polymerization inhibitor added is 0.5 wt% of the TGIC resin solution in step (1).

[0101] The modified TGIC compound obtained in this synthetic example is designated as A-1.

[0102] Synthesis example 2:

[0103] (1) Under an inert gas atmosphere, dipropylene glycol methyl ether is preheated to 105°C, TGIC is added and dissolved, the temperature is lowered to 80°C and methacrylic acid is added, the temperature is raised to 110°C and tetrabutylammonium bromide is added, the temperature is adjusted to 110°C and the reaction is stirred for 10 hours until the acid value of the reaction solution is less than 3 mg KOH / g and the epoxy equivalent is less than 40, thus obtaining a TGIC resin solution containing unsaturated double bonds; the amount of tetrabutylammonium bromide added is 0.5 wt% of the TGIC, and the mass ratio of tricresyl to TGIC is 1:1;

[0104] (2) Cool the TGIC resin solution containing unsaturated double bonds obtained in step (1) to 80°C, then add itaconic anhydride and hydroquinone and mix. Continue to stir and react at 95°C for 5 hours to obtain the modified TGIC compound; wherein the amount of the polymerization inhibitor added is 0.5 wt% of the TGIC resin solution in step (1).

[0105] The modified TGIC compound obtained in this synthesis example is designated as A-2.

[0106] TGIC is designated as R-1, and TAIC (trinyl isocyanurate, Hunan Zhenyuan Chemical Co., Ltd.) is designated as R-2.

[0107] Using the above-described synthesis examples 1-2, the components and their proportions (parts by mass) shown in Table 1 were combined, pre-mixed in a stirrer, and then kneaded using a three-roll mill to prepare an alkali-developable solder resist.

[0108] Table 1

[0109]

[0110] Note *1: 2-Methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, Adamas reagent

[0111] *2: Isopropylthioxanthone, Adamas reagent

[0112] *3: Modified epoxy resin, Heshan Yanmo Technology Co., Ltd.

[0113] *4: Acrylic resin, Heshan Yanmo Technology Co., Ltd.

[0114] *5: Dipropylene glycol methyl ether, Shandong Chuangying Chemical Co., Ltd.

[0115] *6: Divalent acid esters, Shanghai Jiadeer Chemical Technology Co., Ltd.

[0116] *7: Bis(xylenol) type epoxy resin, YX-4000 manufactured by Nippon Epoxy Resin Co., Ltd.

[0117] *8: Bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation

[0118] *9: Barium sulfate

[0119] *10: Spherical silica

[0120] *11: Dicyandiamide

[0121] 2. Testing Methods

[0122] (1) Radioactivity

[0123] Each composition was coated onto a copper plate to form a 30 μm thick film after drying, and then heated at 90°C for 45 minutes. Next, the film was immersed in a 1% sodium carbonate aqueous solution at 30°C for 1 minute, and the developability of the coating surface was visually evaluated according to the following standards.

[0124] ○: The coating is completely removed without any residue, indicating complete development.

[0125] △: Only a small amount of filler remains.

[0126] ×: Residual residue remains.

[0127] (2) Boiling resistance

[0128] The dried coating obtained in the same manner as the development evaluation was subjected to 2J / cm using a UV exposure device. 2 After exposure, the substrate is heated at 160°C for 30 minutes. Then, the substrate is immersed in a solder bath at 260°C and boiled in boiling ion-exchange water for 2 hours. The change in the coating color is then visually evaluated. The judgment criteria are as follows.

[0129] ○: The coating has no abnormalities in appearance.

[0130] △: A slight discoloration was detected.

[0131] ×: The coating appears white overall.

[0132] (3) Solder heat resistance

[0133] A solder resist composition was applied to a printed circuit board (PCB) with circuitry formed using screen printing. The PCB was then dried at 80°C for 30 minutes in a hot air circulating drying oven. A negative film depicting the solder resist pattern was placed on these substrates and exposed at an exposure rate of 2 J / cm². The film was then developed using a 1 wt% sodium carbonate aqueous solution sprayed at 2 MPa for 1 minute to form the solder resist pattern. The substrate was then thermotreated at 150°C for 60 minutes to produce an evaluation substrate.

[0134] Rosin-based flux was applied to the evaluation substrate, which was then immersed in a solder bath set to 260°C for 30 seconds. After cleaning the flux with propylene glycol monomethyl ether acetate, the substrate was dried and a peel test was performed using cellophane tape to evaluate the expansion, peeling, and discoloration of the solder resist layer.

[0135] ○: I didn't see any change at all.

[0136] △: Only minor color changes, etc.

[0137] ×: Existence of solder mask layer expansion, peeling, or discoloration.

[0138] (4) Solvent resistance

[0139] The evaluation substrate, prepared in the same manner as in (3), was immersed in propylene glycol monomethyl ether acetate for 30 minutes and then dried. The dried evaluation substrate was then subjected to a peel test using cellophane tape to evaluate the expansion, peeling, and discoloration of the solder resist layer.

[0140] ○: I didn't see any change at all.

[0141] ×: Existence of solder mask layer expansion, peeling, or discoloration.

[0142] (5) Electroless gold plating durability

[0143] The evaluation substrate was prepared in the same manner as described in (3) above. Using commercially available electroless nickel plating solution and electroless gold plating solution, the evaluation substrate was electroless gold plating was performed to form a 5 μm thick nickel layer and a 0.03 μm thick gold layer. The plated evaluation substrate was then subjected to a peel test using cellophane tape to evaluate the peeling of the solder resist layer and the penetration of the plating.

[0144] ○: I didn't see any change at all.

[0145] △: Only a small amount of peeling occurred, with some seepage.

[0146] ×: Coating peeling exists

[0147] (6) Electroless tin plating resistance

[0148] The evaluation substrate was prepared in the same manner as described in (3) above. The evaluation substrate underwent pretreatment (acidic degreasing + soft etching + sulfuric acid treatment), and electroless tin plating was performed using a commercially available electroless tin plating solution at a plating thickness of 1 μm (70°C, 12 minutes). The tin-plated evaluation substrate was then subjected to a peel test using cellophane tape to evaluate the peeling of the solder resist layer and the penetration of the plating.

[0149] ○: I didn't see any change at all.

[0150] △: Only a small amount of peeling occurred, with some seepage.

[0151] ×: The solder mask layer is completely peeling off.

[0152] (7) Surface curing properties

[0153] The evaluation substrate was prepared in the same manner as in (3) above. The gloss of the resulting cured coating at 60° was evaluated using a BYK Gardner-Micro Tri Gloss meter (manufactured by BYK GmbH, Germany).

[0154] ○: Gloss level after development is 50 or higher

[0155] ×: Gloss level after development is less than 50.

[0156] (8) Pencil hardness test

[0157] Pencils of grades B to 9H with their leads ground flat were pressed at approximately 45° onto test pieces prepared in the same manner as described above, and the hardness of the pencils that did not produce peeling of the coating was recorded. The results are shown in Table 2.

[0158] (9) Peel strength

[0159] The evaluation substrate was prepared in the same manner as described in (3) above. Instead of a printed circuit board with circuitry formed, the copper foil was pretreated. The photocurable resin composition synthesized in the various embodiments and comparative examples was coated onto its surface by screen printing and dried to prepare the evaluation substrate. On the completed insulating layer, a two-component epoxy adhesive was applied to the insulating layer side. The substrate was then flipped over and bonded to the FR-4 substrate on which the 1.6 mm copper layer had been etched on the entire surface. The substrate was cured at 60°C for 5 hours. After curing, a 1 cm wide section of copper foil bonded to the insulating layer was cut and peeled at a 90° angle to perform a test. The peel strength was determined using a peel strength meter.

[0160] ○: 6N or more

[0161] △: 3N or more, less than 6N

[0162] ×: Less than 3N

[0163] (10) Storage stability

[0164] A copper-clad laminate with a copper thickness of 30 μm was selected, and the copper surface was pretreated. Curable resin layers for the various synthetic examples and comparative synthetic examples were formed on this substrate using screen printing, and then dried in an oven at 80°C for 30 minutes to obtain a non-sticky cured resin layer. This substrate was then stored in a high-temperature bath at 30°C for 24 hours, developed, and its storage stability was evaluated based on the following criteria.

[0165] ○: No increase in development time observed.

[0166] △: Development time increased by more than 30% compared to the initial value.

[0167] ×: Development residue is produced.

[0168] The test results of Examples 1-4 and Comparative Examples 1-4 are summarized in Table 2 below:

[0169] Table 2

[0170]

[0171] Comparative Example 5

[0172] Comparative Example 5 is based on the formulation of Comparative Example 1, except that the amount of solvent 1 and solvent 2 added is changed to 20 parts by mass. After pre-mixing in a stirrer, it is kneaded with a three-roll mill to prepare an alkaline developing type solder resist.

[0173] The solder resist exhibits obvious heterogeneity, and the coating surface is very rough after coating and curing.

[0174] Comparative Example 6

[0175] Comparative Example 5 is based on the formulation of Comparative Example 1, except that the amount of solvent 1 and solvent 2 added is changed to 30 parts by mass each. After pre-mixing in a stirrer, it is kneaded with a three-roll mill to prepare an alkaline developing type solder resist.

[0176] The solder resist exhibits obvious heterogeneity, and the coating surface is very rough after coating and curing.

[0177] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for applying an acrylic-modified TGIC additive to a UV photosensitive solder resist ink, characterized in that: The modified TGIC additive is added to the resin matrix solution and blended, with the amount of modified TGIC additive being 1.2~1.3 wt% of the resin matrix. The modified TGIC additive is obtained by first performing a ring-opening reaction between triglycidyl isocyanurate and an active monomer containing an unsaturated double bond, followed by an esterification reaction with an unsaturated acid anhydride. The chemical structural formula of the modified TGIC additive is as follows: ； The addition of the unsaturated double-bond active monomer is carried out in a molar ratio of (1~1.2):1 to the epoxy group of triglycidyl isocyanurate, and the addition of the unsaturated acid anhydride is carried out in a molar ratio of (1~1.2):1 to the epoxy group of triglycidyl isocyanurate. The active monomer containing unsaturated double bonds is acrylic acid; The unsaturated acid anhydride is tetrahydrophthalic anhydride.

2. The application method according to claim 1, characterized in that... The preparation method of the modified TGIC additive includes the following steps: (1) Under an inert gas atmosphere, the solvent is preheated to 100~120℃, triglycidyl isocyanurate is added and dissolved, the temperature is lowered to 60~80℃ and then an active monomer containing unsaturated double bonds is added, the temperature is raised to 100~120℃ and a cyclic ester ring-opening polymerization catalyst is added, the temperature is adjusted to 110~130℃ and the reaction is stirred for 7~12 hours until the acid value of the reaction solution is less than 3mgKOH / g and the epoxy equivalent is less than 40, then a TGIC resin solution containing unsaturated double bonds is obtained. (2) Cool the TGIC resin solution containing unsaturated double bonds obtained in step (1) to 70~80℃, then add unsaturated acid anhydride and polymerization inhibitor and mix, and continue to stir and react at 90~100℃ for 3~7 hours to obtain modified TGIC additive; wherein, the amount of polymerization inhibitor added is 0.4~2.5wt% of the TGIC resin solution in step (1).

3. The application method according to claim 2, characterized in that: The cyclic ester ring-opening polymerization catalyst in step (1) is selected from one of triethylamine, triethanolamine, 4-dimethylaminopyridine, tetrabutylammonium bromide, tetramethylammonium chloride, N,N-dimethylbenzylamine and triphenylphosphine; the amount of cyclic ester ring-opening polymerization catalyst added is 0.2~1wt% of the triglycidyl isocyanurate.

4. The application method according to claim 2, characterized in that: The solvent in step (1) is selected from at least one of ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, propylene glycol methyl ether propionate, dipropylene glycol methyl ether, propylene glycol methyl ether, trimethylbenzene, and tetramethylbenzene; in step (1), the solvent mass: triglycidyl isocyanurate mass = (0.5~1.5):

1.

5. The application method according to claim 1, characterized in that: The resin matrix solution is prepared by dissolving the resin matrix in a solvent, and the amount of solvent added is 10-15 wt% of the resin matrix.

6. The application method according to claim 1, characterized in that: The resin matrix is ​​selected from any one of the following: bisphenol A type epoxy resin, phenolic epoxy resin, o-cresol phenolic epoxy resin, p-tert-butylphenol phenolic epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, diglycidyl phthalate, tetrahydrophthalic acid diglycidyl phthalate, triglycidyl isocyanate, and dicyclodiene epoxide.

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