Itaconic acid-derived glycidyl ether photocurable epoxy resins, their preparation methods, and applications

Abstract

The present invention discloses an itaconic acid-derived glycidyl ether photocurable epoxy resin and its application, wherein firstly, an itaconic acid-derived naphthalene / biphenyl photocurable epoxy resin is provided, wherein the itaconic acid-derived naphthalene / biphenyl photocurable epoxy resin is obtained by firstly subjecting a small molecule naphthalene epoxy compound or a small molecule biphenyl epoxy compound to a ring-opening reaction with itaconic acid, and then subjecting the small molecule naphthalene epoxy compound to an esterification reaction with an unsaturated acid anhydride; secondly, an application of the itaconic acid-derived naphthalene / biphenyl photocurable epoxy resin to replace acrylic acid-modified epoxy resin as a raw material for high-performance photosensitive solder resist ink is provided. The main inventive point of the present invention is to use bio-based itaconic acid as an unsaturated active monomer to modify a small molecule naphthalene epoxy compound or a small molecule biphenyl epoxy compound, so that when it replaces acrylic acid-modified epoxy resin as a raw material for high-performance photosensitive solder resist ink, it has excellent thermomechanical properties and alkali developability.

Description

Technical Field

[0001] The present invention belongs to the technical field of epoxy modifiers, and relates to an itaconic acid derived glycidyl ether type photocurable epoxy resin and its application, and in particular to an itaconic acid derived naphthalene type / biphenyl type photocurable epoxy resin or a compound photocurable epoxy resin as a raw material for photosensitive solder resist ink instead of acrylic acid modified epoxy resin. Background Art

[0002] Photocurable high-performance polymers / resins such as polyester acrylates, polyurethane acrylates, and acrylic modified epoxy resins are widely used as printing inks, packaging coatings, and additive manufacturing. Solder mask coatings for packaging applications are one of the most basic components of flexible integrated printed circuit boards (PCBs). In addition to the traditional role of protecting the copper wires in operation from moisture and high temperature corrosion, it can also relieve the "stress tension and compression" generated when the PCB and integrated circuit substrates (IC carriers) are deformed, thereby preventing them from being damaged. Therefore, the semiconductor industry system has put forward higher standards and requirements for the thermomechanical properties of the solder mask layer. In addition, according to the requirements of the final equipment, the solder mask ink / coating must also meet other functional properties, such as suitable alkali development performance.

[0003] Photoinitiated free radical polymerization (FRP) has been widely used in the photocuring system of solder-resistant coatings due to its advantages of rapid curing, strong adaptability to the surrounding environment, and adjustable time and space. Among them, acrylic modifiers are currently the most mainstream modifiers, but acrylic acid has certain irritating odor, inhalation toxicity and sensitization risks, and its volatile characteristics, which have certain safety and environmental protection issues in actual production and storage.

[0004] Although acrylic modifiers have the above-mentioned disadvantages, due to their relatively ideal alkali developability and other characteristics, the synthesis and composition configuration of photosensitive compounds in the field of solder mask inks still rely on acrylic acid as a free radical crosslinking group. It is obviously difficult to solve the above problems through traditional strategies and synthetic pathways based on acrylic modifiers. Summary of the invention

[0005] In order to solve the problems in the above-mentioned prior art, the present invention provides an itaconic acid-derived glycidyl ether type photocurable epoxy resin and its application. The first invention purpose is to provide an itaconic acid-derived naphthalene / biphenyl type photocurable epoxy resin. The second invention purpose is to provide an application of the above-mentioned itaconic acid-derived naphthalene / biphenyl type photocurable epoxy resin instead of acrylic modified epoxy resin as a raw material for photosensitive solder resist ink.

[0006] To achieve the above objectives, the present invention is implemented by adopting a technical solution consisting of the following technical measures.

[0007] On the one hand, the present invention provides an itaconic acid-derived naphthalene / biphenyl photocurable epoxy resin, which is obtained by firstly subjecting a small molecule naphthalene epoxy compound or a small molecule biphenyl epoxy compound to a ring-opening reaction with itaconic acid, and then subjecting the ring-opening reaction to an esterification reaction with an unsaturated acid anhydride;

[0008] The itaconic acid is added in a molar ratio of (1 to 1.2):1 to the epoxy group of the small molecule naphthalene epoxy compound or the small molecule biphenyl epoxy compound, and the unsaturated acid anhydride is added in a molar ratio of (1 to 4):1 to the epoxy group of the small molecule naphthalene epoxy compound or the small molecule biphenyl epoxy compound;

[0009] The small molecule naphthalene epoxy compound is any one of 1,4-dihydro-1,4-epoxynaphthalene, 1,6-naphthalene diglycidyl ether, and S-(+)-α-naphthyl glycidyl ether;

[0010] The small molecule biphenyl type epoxy compound is any one of 3,3'5,5'-tetramethylbiphenyl bisphenol diglycidyl ether and 2-biphenyl glycidyl ether.

[0011] The main inventive point of the present invention is to use bio-based itaconic acid as an unsaturated active monomer to modify a small molecule naphthalene-type epoxy compound or a small molecule biphenyl-type epoxy compound, not only to introduce an unsaturated carbon-carbon double bond into the two aromatic systems to make them photocurable, but also to carry out a certain structural expansion of the aromatic resin system, so that when it replaces acrylic acid-modified epoxy resin as a raw material for photosensitive solder mask ink, it has excellent thermomechanical properties and alkali developability.

[0012] Itaconic acid is a trifunctional bio-based monomer derived from the fermentation of sugar by Aspergillus terreus. The experiments of this invention have shown that it is expected to be a sustainable alternative to bio-based active vinyl, as a part similar to acrylate in modified photocurable epoxy resin systems. At the same time, it has the characteristics of being a renewable natural resource. Compared with thermal gelation systems, photocrosslinking functional materials have irreplaceable advantages. Therefore, sustainable bio-based derived photocurable and thermally cured thermosetting materials remain the focus of future research and development of high-performance solder mask coating materials. In addition, experiments have found that compared with other bio-based monomers containing double bonds, itaconic acid monomers have stronger photocrosslinking reactivity, but low photocrosslinking density and structural strength also limit the expansion of its application.

[0013] Based on this, the present invention introduces a suitable vinyl functionalized chain extension linking unit by designing a small molecule naphthalene epoxy compound or a small molecule biphenyl epoxy compound through an esterification reaction of itaconic acid and epoxy, and utilizes the relationship between molecular structure and performance to contribute to the controllable preparation and performance enhancement of multifunctional and high-performance resins. In detail, it is to use itaconic acid with a specific trifunctional structure to expand the epoxy unit of the small molecule naphthalene epoxy compound or the small molecule biphenyl epoxy compound under a designed molar ratio during the synthesis process, and to use the ring-opening reaction of the carboxyl group and epoxy, and then introduce bio-based itaconic acid, so that the photosensitivity and cross-linking sites of the intermediate are enriched and strengthened, and then unsaturated anhydrides (especially itaconic anhydrides derived from the same type of bio-based) are introduced through an esterification reaction to give the extended unit rich carboxyl groups, so that it has alkali development characteristics, and the cured product gives the resin high tensile strain and tensile strength while maintaining the high glass transition temperature of the naphthalene / biphenyl unit, which is suitable for preparation and use as a light-cured solder resist ink and a light-cured corrosion-resistant (or electroplating-resistant) ink. In addition, in the electrical insulation performance test, in the designed all-itaconic acid-derived aromatic resin system, thanks to the uniqueness of the extended structure, both resins have good thermomechanical behavior.

[0014] In order to better illustrate the principle of the present invention, one of the technical solutions is now used as an example for description:

[0015] When the unsaturated acid anhydride is itaconic anhydride, the small molecule naphthalene epoxy compound and the small molecule biphenyl epoxy compound are selected as 1,6-naphthalene diglycidyl ether (NDE) and 3,3'5,5'-tetramethylbiphenyl bisphenol diglycidyl ether (TDDE), respectively, and the chemical structural formulas of the raw materials, intermediate products, and final products in the preparation process of the itaconic acid-derived naphthalene / biphenyl type photocurable epoxy resin are as follows:

[0016]

[0017] In this article, the unsaturated anhydride is an unsaturated anhydride conventionally selected for preparing photocurable epoxy resins in the art. Those skilled in the art can select suitable unsaturated anhydrides based on current process conditions or existing technical literature in the art, including monobasic unsaturated anhydrides and polybasic unsaturated anhydrides, and can be selected according to actual process requirements or functional requirements.

[0018] In one technical solution, the unsaturated acid anhydride is preferably a monobasic unsaturated acid anhydride, for example, at least one selected from tetrahydrophthalic anhydride, itaconic anhydride, maleic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride and methylhexahydrophthalic anhydride.

[0019] In one preferred technical solution, the unsaturated acid anhydride is further preferably itaconic anhydride.

[0020] It should be noted that the raw materials of the itaconic acid-derived naphthalene / biphenyl photocurable epoxy resin mainly include small molecule naphthalene epoxy compounds or small molecule biphenyl epoxy compounds, itaconic acid, and unsaturated acid anhydride. Based on the common knowledge of preparing photocurable epoxy resins in the art, solvents, ring-opening reaction catalysts and inhibitors need to be added during the preparation process. The solvents, ring-opening reaction catalysts and inhibitors are the solvents, ring-opening reaction catalysts and inhibitors conventionally selected for preparing photocurable epoxy resins in the art. Those skilled in the art can select suitable solvents, ring-opening reaction catalysts and inhibitors based on the current process conditions or the existing technical literature in the art, or refer to the selection in the following technical scheme.

[0021] In one of the technical solutions, the raw materials of the itaconic acid-derived naphthalene / biphenyl photocurable epoxy resin may also include fillers and / or additives conventionally used in epoxy resins to achieve further functional expansion / process assistance / enhancement of the product. For the specific selection of fillers and / or additives, those skilled in the art may refer to the prior art or existing literature, such as antioxidants, lubricants, carbon-based fillers, coatings, flame retardants, antioxidants, heat stabilizers, coupling agents, plasticizers, compatibilizers, processing aids, etc. It should be noted that the raw materials of the itaconic acid-derived naphthalene / biphenyl photocurable epoxy resin may include fillers and / or additives conventionally used in epoxy resins, or may not include them.

[0022] The above technical scheme provides an itaconic acid-derived naphthalene / biphenyl type photocurable epoxy resin and gives its main synthesis route. Those skilled in the art can prepare itaconic acid-derived naphthalene / biphenyl type photocurable epoxy resin based on the common knowledge of photocurable epoxy resins in the art. Therefore, the following preparation method only provides a preferred technical scheme for reference, and does not mean limitation / designation of the technical scheme of the present invention, nor is it unique.

[0023] The method for preparing the above-mentioned itaconic acid-derived naphthalene / biphenyl type photocurable epoxy resin mainly comprises the following steps:

[0024] (1) In an air atmosphere, preheat the solvent to 70-90° C., add a small molecular naphthalene epoxy compound or a small molecular biphenyl epoxy compound and dissolve it, cool it to 50-60° C., add itaconic acid, then heat it to 70-80° C., add a ring-opening reaction catalyst and a polymerization inhibitor, then adjust the temperature to 100-120° C. and stir the reaction at this temperature for 10-15 hours to obtain an intermediate product;

[0025] (2) The intermediate product obtained in step (1) is cooled to 70-80° C., and then an unsaturated acid anhydride and an inhibitor are added, and the temperature is raised to 85-100° C. and stirred for reaction for 7-12 hours to prepare an itaconic acid-derived naphthalene-type photocurable epoxy resin or an itaconic acid-derived biphenyl-type photocurable epoxy resin.

[0026] In this article, the solvent described in step (1) is a solvent conventionally selected in the art for preparing photocurable epoxy resins. Those skilled in the art can select a suitable solvent based on the current process conditions or existing technical literature in the art, such as a conventional organic solvent, and can be selected according to actual process requirements or functional requirements.

[0027] In one of the technical schemes, the solvent in step (1) is preferably at least one of a divalent acid ester high boiling point environmentally friendly solvent, 2-(2-ethoxyethoxy)ethyl acetate, ethylene glycol butyl acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl 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 mass of the solvent: the mass of the small molecule naphthalene type epoxy compound or the small molecule biphenyl type epoxy compound = (0.5~1.5): 1.

[0028] Herein, the catalyst for the ring-opening reaction in step (1) is a catalyst commonly used in the art for the ring-opening reaction of epoxy compounds. Those skilled in the art can select a suitable catalyst for the ring-opening reaction according to actual needs.

[0029] In one of the technical solutions, the catalyst for the ring-opening reaction in step (1) is selected from one of triethylamine, triethanolamine, 4-dimethylaminopyridine, tetrabutylammonium bromide, tetramethylammonium chloride, N,N-dimethylbenzylamine and triphenylphosphine; the amount of the catalyst added for the ring-opening reaction is 0.2 to 1 wt% of the small molecule naphthalene-type epoxy compound or the small molecule biphenyl-type epoxy compound.

[0030] Herein, the polymerization inhibitors in steps (1) and (2) are polymerization inhibitors conventionally selected in the art for preparing photocurable epoxy resins. Those skilled in the art can select suitable polymerization inhibitors based on current process conditions or existing technical literature in the art.

[0031] In one technical solution, the polymerization inhibitor in steps (1) and (2) is preferably at least one of hydroquinone, o-methyl hydroquinone, p-hydroxyanisole, p-benzoquinone and 2,6-di-tert-butyl-4-methylphenol. Preferably, the polymerization inhibitor added twice is the same polymerization inhibitor, and the amount of the polymerization inhibitor added each time is 0.4 to 2.5 wt % of the small molecule naphthalene epoxy compound or small molecule biphenyl epoxy compound in step (1).

[0032] Herein, the stirring reaction in steps (1) and (2) is a stirring reaction conventionally used in the art, including magnetic stirring or mechanical stirring, and those skilled in the art can select a suitable stirring reaction mode according to the production scale or the current process conditions. In order to better illustrate the present invention and provide a process scheme suitable for a laboratory operating environment, the stirring reaction can be carried out at a stirring rate of 100 to 300 rpm.

[0033] On the other hand, based on the above-mentioned itaconic acid-derived naphthalene type / biphenyl type photocurable epoxy resin (itaconic acid-derived naphthalene type photocurable epoxy resin or itaconic acid-derived biphenyl type photocurable epoxy resin), the present invention also provides a photosensitive solder resist ink using the above-mentioned itaconic acid-derived naphthalene type / biphenyl type photocurable epoxy resin as a main component, and its raw materials mainly include, by weight:

[0034] 100 parts of itaconic acid derived naphthalene type / biphenyl type photocurable epoxy resin,

[0035] 1 to 5 parts of photoinitiator.

[0036] Herein, the photoinitiator is a photoinitiator conventionally selected for preparing photosensitive solder resist ink in the art, and those skilled in the art can select a suitable photoinitiator based on the current process conditions or existing technical literature in the art.

[0037] In one of the technical solutions, the photoinitiator is preferably at least one of 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide, 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone, 2-hydroxy-4-(2-hydroxyethoxyphenyl)-2-methylpropiophenone, 2-isopropylthioxanthone (2,4 isomers), 2-hydroxy-2-methyl-1-phenylpropiophenone, 1-hydroxycyclohexylphenylmethanol, benzoin ethyl ether, benzil dimethyl ketal, 1-hydroxyphenylhexylacetophenone, benzophenone / triethanolamine and benzophenone / acrylate active amine.

[0038] In order to further improve the thermomechanical properties and developability of the photosensitive solder resist ink, in one of the more preferred technical solutions, the present invention also provides a photosensitive solder resist ink using the above-mentioned itaconic acid-derived naphthalene type and biphenyl type composite photocurable epoxy resin as the main component, and its raw materials mainly include by weight:

[0039] 50 to 83.33 parts of itaconic acid-derived naphthalene-type photocurable epoxy resin,

[0040] 16.67 to 50 parts of itaconic acid-derived biphenyl type photocurable epoxy resin,

[0041] 1 to 5 parts of photoinitiator;

[0042] The itaconic acid-derived naphthalene type photocurable epoxy resin and the itaconic acid-derived biphenyl type photocurable epoxy resin total 100 parts.

[0043] In one preferred technical solution, the raw materials of the photosensitive solder resist ink, measured by weight, further include:

[0044] 20 to 50 parts of filler,

[0045] 1 to 25 parts of additives.

[0046] Among them, in order to improve the physical strength of the coating after the solder resist ink is used, the solder resist ink component includes a filler, and the filler is a well-known inorganic or organic filler, preferably one or more of titanium dioxide, bentonite, barium sulfate, spherical silica, nano calcium carbonate, and talc. Furthermore, it is preferred that well-known metal oxides are used as both fillers and pigments.

[0047] The additive is one or more combinations of pigments, thermal inhibitors, tackifiers, defoamers, leveling agents, coupling agents, antioxidants and rust inhibitors. Generally, the pigments, thermal inhibitors, tackifiers, defoamers, leveling agents, coupling agents, antioxidants and rust inhibitors are well known and commonly used.

[0048] The preparation method of the above-mentioned photosensitive solder resist ink can be prepared by mixing all the components in accordance with the prior art. For example, the components are preliminarily mixed in a blender and then kneaded in a three-roll mill to obtain the novel photocurable solder resist ink.

[0049] When the above solder resist ink is used, it is applied to the substrate, dried appropriately (about 60 to 120°C), and then exposed through a pattern film to obtain a cured coating film, and the unexposed portion is developed. When developing, the above solvent or a well-known halogen solvent such as trichloroethylene can be used for solvent development, preferably alkaline development. For alkaline solvent development, alkali metal compounds such as sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, etc. can be selected; alkaline earth metal compounds such as calcium hydroxide can also be selected; alkaline solution ammonia water can also be selected; water-soluble organic amines such as monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monopropylamine, dipropylamine, dimethylpropylamine, monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, diethylenetriamine, dimethylaminoethyl methacrylate, polyethyleneimine, etc. can also be selected.

[0050] Generally, the photosensitive solder resist ink can be directly applied to a substrate in a liquid state or used in a state of a solder resist layer dry film formed by applying the ink on a film such as PET and drying the film in advance.

[0051] The present invention has the following beneficial effects:

[0052] 1. The present invention utilizes trifunctional itaconic acid to respectively end-cap simple epoxy molecules containing naphthalene and biphenyl as main molecular structures, introduces a designed amount of carboxyl end-capping units in the first step of esterification ring-opening reaction, and then utilizes difunctional carboxyl groups to further participate in the esterification reaction of multifunctional epoxy to introduce bio-based itaconic acid structures at both ends of aromatic resins, thereby synthesizing chain-extended epoxy molecules with photo-crosslinking properties.

[0053] 2. In the present invention, itaconic anhydride derived from itaconic acid is used to esterify with the hydroxyl group produced in the second step esterification ring-opening reaction and the acid anhydride, and then a large number of abundant unsaturated double bonds and carboxyl groups are introduced to make the synthetic resin have a higher double bond density and acidity, and the film after curing has a high glass transition temperature and flexibility.

[0054] 3. In the present invention, by extending the two aromatic units with bio-based itaconic acid at a designed amount, the structure is endowed with high cross-linking and heat-resistant characteristics, as well as an excellent anti-mechanical damping structure, achieving high tensile strength and tensile strain.

[0055] 4. In a preferred technical solution of the present invention, by compounding itaconic acid-derived naphthalene-type photocurable epoxy resin or itaconic acid-derived biphenyl-type photocurable epoxy resin as a photosensitive solder resist ink as the main component, under certain mass ratio conditions, compared with the photosensitive solder resist ink with each of them as the main component alone, its thermomechanical properties can be further greatly improved, and the extent of improvement in the thermomechanical properties exceeds the expectations of those skilled in the art.

[0056] 5. In the present invention, a large number of carboxyl groups are introduced by the reaction of acid anhydride and hydroxyl groups, so that the product has good alkali developability, and can be quickly and completely detached by directly immersing in concentrated alkali solution without damaging the substrate.

[0057] 6. The photosensitive solder resist ink in the preferred embodiment provided by the present invention has been tested and has excellent performance in mechanical properties, resistance to soldering heat, solvent resistance, voltage breakdown resistance, chemical resistance, electroless gold plating resistance, electroless tin plating resistance, and electrical insulation properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 The comparison diagram of the H NMR spectra of the raw materials, intermediate products and final products used in Synthesis Examples 1 to 2 of the present invention. In the figure, (a) is the H NMR spectra of the raw material 1,6-naphthalene diglycidyl ether (NDE), the intermediate product (IEN-α) and the final product (IEN) used in Synthesis Example 1; (b) is the H NMR spectra of the raw material 3,3'5,5'-tetramethylbiphenyl bisphenol diglycidyl ether (TDDE), the intermediate product (IET-α) and the final product (IET) used in Synthesis Example 2.

[0059] Figure 2 The thermomechanical properties of the samples obtained by curing the photosensitive solder resist inks prepared in Examples 1 to 5 of the present invention are compared by DMTA test. Among them, IEN is the photosensitive solder resist ink obtained in Example 1, IET is the photosensitive solder resist ink obtained in Example 2, IEN5T1 is the photosensitive solder resist ink obtained in Example 3, IEN2T1 is the photosensitive solder resist ink obtained in Example 4, and IEN1T1 is the photosensitive solder resist ink obtained in Example 5.

[0060] Figure 3 The mechanical properties comparison diagram of the samples obtained after curing the photosensitive solder resist ink prepared in Examples 1 to 5 of the present invention. Among them, (a) is a stress performance comparison column chart of the cured samples of Examples 1 to 5; (b) is a strain performance comparison column chart of the cured samples of Examples 1 to 5; (c) is a toughness performance comparison column chart of the cured samples of Examples 1 to 5; IEN is the photosensitive solder resist ink obtained in Example 1, IET is the photosensitive solder resist ink obtained in Example 2, IEN5T1 is the photosensitive solder resist ink obtained in Example 3, IEN2T1 is the photosensitive solder resist ink obtained in Example 4, and IEN1T1 is the photosensitive solder resist ink obtained in Example 5.

[0061] Figure 4 The alkali development performance comparison diagram of the photosensitive solder resist inks prepared in Examples 1 to 5 of the present invention is shown in FIG. Among them, (a) is a comparison photo of the development time test; (b) is a statistical comparison bar chart of the development time; IEN is the photosensitive solder resist ink obtained in Example 1, IET is the photosensitive solder resist ink obtained in Example 2, IEN5T1 is the photosensitive solder resist ink obtained in Example 3, IEN2T1 is the photosensitive solder resist ink obtained in Example 4, and IEN1T1 is the photosensitive solder resist ink obtained in Example 5.

[0062] Figure 5 This is a comparative line chart of the unsaturated double bond conversion rates of the final products prepared in Synthesis Examples 1 and 2 of the present invention. DETAILED DESCRIPTION

[0063] In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments, and relevant personnel can obviously change or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention. Although it is believed that those of ordinary skill in the art fully understand the following terms, the following definitions are still stated to help illustrate the subject matter disclosed by the present invention.

[0064] On the one hand, the present invention provides an itaconic acid-derived naphthalene / biphenyl photocurable epoxy resin, which is obtained by firstly subjecting a small molecule naphthalene epoxy compound or a small molecule biphenyl epoxy compound to a ring-opening reaction with itaconic acid, and then subjecting the ring-opening reaction to an esterification reaction with an unsaturated acid anhydride;

[0065] The itaconic acid is added in a molar ratio of (1 to 1.2):1 to the epoxy group of the small molecule naphthalene epoxy compound or the small molecule biphenyl epoxy compound, and the unsaturated acid anhydride is added in a molar ratio of (1 to 4):1 to the epoxy group of the small molecule naphthalene epoxy compound or the small molecule biphenyl epoxy compound;

[0066] The small molecule naphthalene epoxy compound is any one of 1,4-dihydro-1,4-epoxynaphthalene, 1,6-naphthalene diglycidyl ether, and S-(+)-α-naphthyl glycidyl ether;

[0067] The small molecule biphenyl type epoxy compound is any one of 3,3'5,5'-tetramethylbiphenyl bisphenol diglycidyl ether and 2-biphenyl glycidyl ether.

[0068] The main inventive point of the present invention is to use bio-based itaconic acid as an unsaturated active monomer to modify a small molecule naphthalene-type epoxy compound or a small molecule biphenyl-type epoxy compound, not only to introduce an unsaturated carbon-carbon double bond into the two aromatic systems to make them photocurable, but also to carry out a certain structural expansion of the aromatic resin system, so that when it replaces acrylic acid-modified epoxy resin as a raw material for photosensitive solder mask ink, it has excellent thermomechanical properties and alkali developability.

[0069] Itaconic acid is a trifunctional bio-based monomer derived from the fermentation of sugar by Aspergillus terreus. The experiments of this invention have shown that it is expected to be a sustainable alternative to bio-based active vinyl, as a part similar to acrylate in modified photocurable epoxy resin systems. At the same time, it has the characteristics of being a renewable natural resource. Compared with thermal gelation systems, photocrosslinking functional materials have irreplaceable advantages. Therefore, sustainable bio-based derived photocurable and thermally cured thermosetting materials remain the focus of future research and development of high-performance solder mask coating materials. In addition, experiments have found that compared with other bio-based monomers containing double bonds, itaconic acid monomers have stronger photocrosslinking reactivity, but low photocrosslinking density and structural strength also limit the expansion of its application.

[0070] Based on this, the present invention introduces a suitable vinyl functionalized chain extension linking unit by designing a small molecule naphthalene epoxy compound or a small molecule biphenyl epoxy compound through an esterification reaction of itaconic acid and epoxy, and utilizes the relationship between molecular structure and performance to contribute to the controllable preparation and performance enhancement of multifunctional and high-performance resins. In detail, it is to use itaconic acid with a specific trifunctional structure to expand the epoxy unit of the small molecule naphthalene epoxy compound or the small molecule biphenyl epoxy compound under a designed molar ratio during the synthesis process, and to use the ring-opening reaction of the carboxyl group and epoxy, and then introduce bio-based itaconic acid, so that the photosensitivity and cross-linking sites of the intermediate are enriched and strengthened, and then unsaturated anhydrides (especially itaconic anhydrides derived from the same type of bio-based) are introduced through an esterification reaction to give the extended unit rich carboxyl groups, so that it has alkali development characteristics, and the cured product gives the resin high tensile strain and tensile strength while maintaining the high glass transition temperature of the naphthalene / biphenyl unit, which is suitable for preparation and use as a light-cured solder resist ink and a light-cured corrosion-resistant (or electroplating-resistant) ink. In addition, in the electrical insulation performance test, in the designed all-itaconic acid-derived aromatic resin system, thanks to the uniqueness of the extended structure, both resins have good thermomechanical behavior.

[0071] In order to better illustrate the principle of the present invention, one of the embodiments is now described as an example:

[0072] When the unsaturated acid anhydride is itaconic anhydride, the small molecule naphthalene epoxy compound and the small molecule biphenyl epoxy compound are selected as 1,6-naphthalene diglycidyl ether (NDE) and 3,3'5,5'-tetramethylbiphenyl bisphenol diglycidyl ether (TDDE), respectively, and the chemical structural formulas of the raw materials, intermediate products, and final products in the preparation process of the itaconic acid-derived naphthalene / biphenyl type photocurable epoxy resin are as follows:

[0073]

[0074] In this article, the unsaturated anhydride is an unsaturated anhydride conventionally selected in the art for preparing photocurable epoxy resins. Those skilled in the art can select suitable unsaturated anhydrides based on current process conditions or existing technical literature in the art. In one embodiment, the selection includes monounsaturated anhydrides and polyunsaturated anhydrides, both of which can be selected according to actual process requirements or functional requirements.

[0075] In one embodiment, the unsaturated acid anhydride is preferably a monobasic unsaturated acid anhydride, for example, at least one selected from tetrahydrophthalic anhydride, itaconic anhydride, maleic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride and methylhexahydrophthalic anhydride.

[0076] In one preferred embodiment, the unsaturated acid anhydride is further preferably itaconic anhydride.

[0077] It should be noted that the raw materials of the itaconic acid-derived naphthalene / biphenyl photocurable epoxy resin mainly include small molecule naphthalene epoxy compounds or small molecule biphenyl epoxy compounds, itaconic acid, and unsaturated acid anhydride. Based on the common knowledge of preparing photocurable epoxy resins in the art, solvents, ring-opening reaction catalysts and inhibitors need to be added during the preparation process. The solvents, ring-opening reaction catalysts and inhibitors are the solvents, ring-opening reaction catalysts and inhibitors conventionally selected for preparing photocurable epoxy resins in the art. Those skilled in the art can select suitable solvents, ring-opening reaction catalysts and inhibitors based on the current process conditions or the existing technical literature in the art, or refer to the selection in the following technical scheme.

[0078] In one embodiment, the raw materials of the itaconic acid-derived naphthalene / biphenyl photocurable epoxy resin may also include fillers and / or additives conventionally used in epoxy resins to achieve further functional expansion / process assistance / enhancement of the product. The specific fillers and / or additives can be selected by those skilled in the art based on the prior art or existing literature, such as antioxidants, lubricants, carbon-based fillers, coatings, flame retardants, antioxidants, thermal stabilizers, coupling agents, plasticizers, compatibilizers, processing aids, etc. It should be noted that the raw materials of the itaconic acid-derived naphthalene / biphenyl photocurable epoxy resin may include fillers and / or additives conventionally used in epoxy resins, or may not include them.

[0079] In one embodiment, the itaconic acid is added in a molar ratio of (1 to 1.2) to the epoxy group of the small molecule naphthalene-type epoxy compound or the small molecule biphenyl-type epoxy compound: 1, for example, the molar ratio is 1:1, 1.05:1, 1.1:1, 1.15:1, 1.2:1 or any range or point value therebetween.

[0080] In one embodiment, the unsaturated acid anhydride is added in a molar ratio of (1 to 4) : 1 to the epoxy group of the small molecule naphthalene-type epoxy compound or the small molecule biphenyl-type epoxy compound, for example, the molar ratio is 1:1, 1.05:1, 1.1:1, 1.15:1, 1.2:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 3.8:1, 4:1 or any range or point value therebetween.

[0081] The above technical scheme provides an itaconic acid-derived naphthalene / biphenyl type photocurable epoxy resin and gives its main synthesis route. Those skilled in the art can prepare itaconic acid-derived naphthalene / biphenyl type photocurable epoxy resin based on the common knowledge of photocurable epoxy resins in the art. Therefore, the following preparation method only provides a preferred implementation for reference, and does not mean a limitation / designation of the implementation of the present invention, nor is it unique.

[0082] The method for preparing the above-mentioned itaconic acid-derived naphthalene / biphenyl type photocurable epoxy resin mainly comprises the following steps:

[0083] (1) In an air atmosphere, preheat the solvent to 70-90° C., add a small molecular naphthalene epoxy compound or a small molecular biphenyl epoxy compound and dissolve it, cool it to 50-60° C., add itaconic acid, then heat it to 70-80° C., add a ring-opening reaction catalyst and a polymerization inhibitor, then adjust the temperature to 100-120° C. and stir the reaction at this temperature for 10-15 hours to obtain an intermediate product;

[0084] (2) The intermediate product obtained in step (1) is cooled to 70-80° C., and then an unsaturated acid anhydride and an inhibitor are added, and the temperature is raised to 85-100° C. and stirred for reaction for 7-12 hours to prepare an itaconic acid-derived naphthalene-type photocurable epoxy resin or an itaconic acid-derived biphenyl-type photocurable epoxy resin.

[0085] In this article, the solvent described in step (1) is a solvent conventionally selected in the art for preparing photocurable epoxy resins. Those skilled in the art can select a suitable solvent based on the current process conditions or existing technical literature in the art, such as a conventional organic solvent, and can be selected according to actual process requirements or functional requirements.

[0086] In one embodiment, the solvent in step (1) is preferably at least one of a divalent acid ester high boiling point environmentally friendly solvent, 2-(2-ethoxyethoxy)ethyl acetate, ethylene glycol butyl acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl 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 mass of the solvent: the mass of the small molecule naphthalene type epoxy compound or the small molecule biphenyl type epoxy compound = (0.5~1.5): 1.

[0087] Herein, the catalyst for the ring-opening reaction in step (1) is a catalyst commonly used in the art for the ring-opening reaction of epoxy compounds. Those skilled in the art can select a suitable catalyst for the ring-opening reaction according to actual needs.

[0088] In one embodiment, the catalyst for the ring-opening reaction in step (1) is selected from one of triethylamine, triethanolamine, 4-dimethylaminopyridine, tetrabutylammonium bromide, tetramethylammonium chloride, N,N-dimethylbenzylamine and triphenylphosphine; the amount of the catalyst added for the ring-opening reaction is 0.2 to 1 wt% of the small molecule naphthalene-type epoxy compound or the small molecule biphenyl-type epoxy compound.

[0089] Herein, the polymerization inhibitors in steps (1) and (2) are polymerization inhibitors conventionally selected in the art for preparing photocurable epoxy resins. Those skilled in the art can select suitable polymerization inhibitors based on current process conditions or existing technical literature in the art.

[0090] In one embodiment, the polymerization inhibitor in steps (1) and (2) is preferably at least one of hydroquinone, o-methyl hydroquinone, p-hydroxyanisole, p-benzoquinone and 2,6-di-tert-butyl-4-methylphenol. Preferably, the polymerization inhibitor added twice is the same polymerization inhibitor, and the amount of the polymerization inhibitor added each time is 0.4 to 2.5 wt% of the small molecule naphthalene-type epoxy compound or small molecule biphenyl-type epoxy compound in step (1).

[0091] Herein, the stirring reaction in steps (1) and (2) is a stirring reaction conventionally used in the art, including magnetic stirring or mechanical stirring, and those skilled in the art can select a suitable stirring reaction mode according to the production scale or the current process conditions. In order to better illustrate the present invention and provide a process scheme suitable for a laboratory operating environment, the stirring reaction can be carried out at a stirring rate of 100 to 300 rpm.

[0092] On the other hand, based on the above-mentioned itaconic acid-derived naphthalene type / biphenyl type photocurable epoxy resin (itaconic acid-derived naphthalene type photocurable epoxy resin or itaconic acid-derived biphenyl type photocurable epoxy resin), the present invention also provides a photosensitive solder resist ink using the above-mentioned itaconic acid-derived naphthalene type / biphenyl type photocurable epoxy resin as a main component, and its raw materials mainly include, by weight:

[0093] 100 parts of itaconic acid derived naphthalene type / biphenyl type photocurable epoxy resin,

[0094] 1 to 5 parts of photoinitiator.

[0095] Herein, the photoinitiator is a photoinitiator conventionally selected for preparing photosensitive solder resist ink in the art, and those skilled in the art can select a suitable photoinitiator based on the current process conditions or existing technical literature in the art.

[0096] In one embodiment, the photoinitiator is preferably at least one of 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide, 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone, 2-hydroxy-4-(2-hydroxyethoxyphenyl)-2-methylpropiophenone, 2-isopropylthioxanthone (2,4 isomers), 2-hydroxy-2-methyl-1-phenylpropiophenone, 1-hydroxycyclohexylphenylmethanol, benzoin ethyl ether, benzil dimethyl ketal, 1-hydroxyphenylhexylacetophenone, benzophenone / triethanolamine and benzophenone / acrylate active amine.

[0097] In order to further improve the thermomechanical properties and developability of the photosensitive solder resist ink, in one of the more preferred embodiments, the present invention further provides a photosensitive solder resist ink using the above-mentioned itaconic acid-derived naphthalene type and biphenyl type composite photocurable epoxy resin as the main component, and its raw materials mainly include by weight:

[0098] 50 to 83.33 parts of itaconic acid-derived naphthalene-type photocurable epoxy resin,

[0099] 16.67 to 50 parts of itaconic acid-derived biphenyl type photocurable epoxy resin,

[0100] 1 to 5 parts of photoinitiator;

[0101] The itaconic acid-derived naphthalene type photocurable epoxy resin and the itaconic acid-derived biphenyl type photocurable epoxy resin total 100 parts.

[0102] In one preferred embodiment, the photosensitive solder resist ink further comprises, by weight:

[0103] 20 to 50 parts of filler,

[0104] 1 to 25 parts of additives.

[0105] Among them, in order to improve the physical strength of the coating after the solder resist ink is used, the solder resist ink component includes a filler, and the filler is a well-known inorganic or organic filler. In one embodiment, one or more of titanium dioxide, bentonite, barium sulfate, spherical silica, nano-calcium carbonate, and talc are preferred. Furthermore, well-known metal oxides are preferably used as both fillers and pigments.

[0106] Wherein, the additive, in one embodiment, is one or more combinations of pigment, thermal inhibitor, tackifier, defoamer, leveling agent, coupling agent, antioxidant and rust inhibitor. Generally, the above-mentioned pigment, thermal inhibitor, tackifier, defoamer, leveling agent, coupling agent, antioxidant and rust inhibitor are well-known and commonly used.

[0107] The preparation method of the above-mentioned photosensitive solder resist ink can be prepared by mixing all the components in accordance with the prior art. For example, the components are preliminarily mixed in a blender and then kneaded in a three-roll mill to obtain the novel photocurable solder resist ink.

[0108] When the above solder resist ink is used, it is applied to the substrate, dried appropriately (about 60 to 120°C), and then exposed through a pattern film to obtain a cured coating film, and the unexposed portion is developed. When developing, the above solvent or a well-known halogen solvent such as trichloroethylene can be used for solvent development, preferably alkaline development. For alkaline solvent development, alkali metal compounds such as sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, etc. can be selected; alkaline earth metal compounds such as calcium hydroxide can also be selected; alkaline solution ammonia water can also be selected; water-soluble organic amines such as monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monopropylamine, dipropylamine, dimethylpropylamine, monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, diethylenetriamine, dimethylaminoethyl methacrylate, polyethyleneimine, etc. can also be selected.

[0109] Generally, the photosensitive solder resist ink can be directly applied to a substrate in a liquid state or used in a state of a solder resist layer dry film formed by applying the ink on a film such as PET and drying the film in advance.

[0110] The present invention will be further explained in detail with reference to the following examples. However, it should be understood by those skilled in the art that these examples are provided for illustrative purposes only and are not intended to limit the present invention.

[0111] Example

[0112] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. The specific conditions not specified in the examples are carried out according to the conditions recommended by normal conditions or manufacturers. The reagents used or the instruments not specified by the manufacturer are all conventional products that can be obtained commercially. The application should not be construed as being limited to the specific examples described.

[0113] 1. Raw materials

[0114] 1,6-naphthalene diglycidyl ether (NDE) was purchased from DIC Corporation (Tokyo, Japan).

[0115] 3,3',5,5'-Tetramethyl-4,4'-diphenol diglycidyl ether (TDDE) was purchased from Tiantai High-Tech Co., Ltd. (Guangzhou, China).

[0116] Hydroquinone (HQ), triphenylphosphine (TPP), and ethyl 2-(2-ethoxyethoxy)acetate (DCAC) were from Huaxia Reagent Co., Ltd. (Chengdu, China).

[0117] Itaconic acid (IAc), itaconic anhydride (IA) and photoinitiator 2-isopropylthioxanthone (ITX) were provided by Sinopharm Chemical Reagent Co., Ltd.

[0118] 2. Test methods

[0119] Nuclear magnetic resonance spectra (NMR) were measured using a Bruker ARX 600 NMR spectrometer from Bruker Corporation, USA, using dimethyl sulfoxide-d6 (DMSO-d6) as solvent.

[0120] Dynamic mechanical thermal analyzer (DMTA, TAInstrumentsQ850) was used to test stress-strain curve and glass transition temperature in tensile mode. Stress-strain curve measurement: After curing, the sample was balanced at 25°C and 0.1N preload, and the load force was increased at a rate of 0.2N / min. In addition, in tensile mode and 0.01N preload, the sample was heated at 5°C / min. -1 The tensile velocity is used to measure the stability of the sample as it changes with temperature.

[0121] The DC voltage breakdown strength of the cured sample was recorded using a breakdown voltage tester with a rated voltage upper limit of 100 kV (Beijing Guance Precision Instrument Equipment). The size of the test sample was 20 mm × 20 mm; the thickness was 0.10 to 0.15 mm.

[0122] The photopolymerization kinetics of the photosensitive ink was studied using a Nicolet 560 Fourier transform infrared spectrometer (Nicolet, USA) and a 395 nm ultraviolet point light source (IUVOT, Japan). The unsaturated double bond conversion (DC) was measured based on the wavelength of 1730 cm -1 The intensity of the carbonyl peak was used as the internal standard and the calculated value was 1630 cm -1 The attenuation of the double bond absorption peak at .

[0123] Using 1% Na2CO3 aqueous solution as the developer, the photosensitive ink was coated on one side of the cleaned and dried surface of the slide, and the coating area was fixed to 2.54cm×7.62cm. After drying at room temperature for 1 hour, the uncured ink coating was rinsed at 30°C and the time required for complete elution was recorded.

[0124] Synthesis example 1

[0125] This synthesis example provides a method for preparing an itaconic acid-derived naphthalene-type photocurable epoxy resin, which mainly includes the following steps:

[0126] (1) In an air atmosphere, the solvent ethyl 2-(2-ethoxyethoxy)acetate is preheated to 70°C, 1,6-naphthalene diglycidyl ether is added and dissolved, the temperature is lowered to 50°C, itaconic acid is added, the temperature is raised to 80°C, triphenylphosphine catalyst for ring-opening reaction and hydroquinone inhibitor are added, the temperature is adjusted to 110°C, and the reaction is stirred at this temperature for 15 hours to obtain an intermediate product, which is named IEN-α;

[0127] The itaconic acid is added in a molar ratio of 1:1 to the epoxy group of 1,6-naphthalene diglycidyl ether;

[0128] The mass of the solvent: the mass of 1,6-naphthalene diglycidyl ether = 1:1;

[0129] The catalyst for the ring-opening reaction is added in an amount of 0.8 wt % of the 1,6-naphthalene diglycidyl ether;

[0130] The addition amount of the polymerization inhibitor is 0.4wt% of 1,6-naphthalene diglycidyl ether;

[0131] (2) cooling the intermediate product obtained in step (1) to 70° C., then adding itaconic anhydride and a polymerization inhibitor hydroquinone, heating to 95° C. and stirring for reaction for 8 hours to prepare an itaconic acid-derived naphthalene-type photocurable epoxy resin, named IEN;

[0132] The itaconic anhydride is added in a molar ratio of 4:1 to the epoxy group of 1,6-naphthalene diglycidyl ether;

[0133] The addition amount of the polymerization inhibitor is 0.4 wt % of 1,6-naphthalene diglycidyl ether.

[0134] Synthesis example 2

[0135] This synthesis example provides a method for preparing an itaconic acid-derived naphthalene-type photocurable epoxy resin, which mainly includes the following steps:

[0136] (1) In an air atmosphere, the solvent ethyl 2-(2-ethoxyethoxy)acetate is preheated to 90°C, 3,3'5,5'-tetramethylbiphenyl bisphenol diglycidyl ether is added and dissolved, the temperature is lowered to 50°C, itaconic acid is added, the temperature is raised to 80°C, triphenylphosphine catalyst for ring-opening reaction and hydroquinone inhibitor are added, the temperature is adjusted to 110°C, and the reaction is stirred at this temperature for 15 hours to obtain an intermediate product, which is named IET-α;

[0137] The itaconic acid is added in a molar ratio of 1:1 to the epoxy group of 3,3'5,5'-tetramethylbiphenyl bisphenol diglycidyl ether;

[0138] The mass of the solvent: the mass of 3,3'5,5'-tetramethylbiphenyl bisphenol diglycidyl ether = 1:1;

[0139] The catalyst for the ring-opening reaction is added in an amount of 0.8 wt % of the 3,3'5,5'-tetramethylbiphenyl bisphenol diglycidyl ether;

[0140] The addition amount of the polymerization inhibitor is 0.4wt% of 3,3'5,5'-tetramethylbiphenyl bisphenol diglycidyl ether;

[0141] (2) cooling the intermediate product obtained in step (1) to 70° C., then adding itaconic anhydride and a polymerization inhibitor hydroquinone, heating to 95° C. and stirring for reaction for 8 hours to prepare an itaconic acid-derived biphenyl type photocurable epoxy resin, named IET;

[0142] The itaconic anhydride is added in a molar ratio of 4:1 to the epoxy group of 3,3'5,5'-tetramethylbiphenyl bisphenol diglycidyl ether;

[0143] The addition amount of the polymerization inhibitor is 0.4 wt % of 3,3'5,5'-tetramethylbiphenyl bisphenol diglycidyl ether.

[0144] Example 1

[0145] In this embodiment 1, the following raw material components are preliminarily mixed in a blender according to their weight proportions, and then kneaded using a three-roll mill to obtain a photosensitive solder resist ink:

[0146] Itaconic acid derived naphthalene type photocurable epoxy resin (IEN) 100 parts,

[0147] Photoinitiator (2-isopropylthioxanthone) 3 parts.

[0148] Example 2

[0149] In this embodiment 2, the following raw material components are preliminarily mixed in a blender according to weight, and then kneaded using a three-roll mill to obtain a photosensitive solder resist ink:

[0150] Itaconic acid derived biphenyl type light curing epoxy resin (IET) 100 parts,

[0151] Photoinitiator (2-isopropylthioxanthone) 3 parts.

[0152] Example 3

[0153] In this embodiment 3, the following raw material components are preliminarily mixed in a blender according to weight, and then kneaded using a three-roll mill to obtain a photosensitive solder resist ink:

[0154] Itaconic acid derived naphthalene type photocurable epoxy resin (IEN) 83.33 parts,

[0155] Itaconic acid derived biphenyl type photocurable epoxy resin (IET) 16.67 parts,

[0156] Photoinitiator (2-isopropylthioxanthone) 3 parts.

[0157] Example 4

[0158] In this embodiment 4, the following raw material components are preliminarily mixed in a blender by weight, and then kneaded by a three-roll mill to obtain a photosensitive solder resist ink:

[0159] Itaconic acid-derived naphthalene-based photocurable epoxy resin (IEN) 66.67 parts,

[0160] Itaconic acid derived biphenyl type photocurable epoxy resin (IET) 33.33 parts,

[0161] Photoinitiator (2-isopropylthioxanthone) 3 parts.

[0162] Example 5

[0163] In this embodiment 5, the following raw material components are preliminarily mixed in a blender according to weight, and then kneaded using a three-roll mill to obtain a photosensitive solder resist ink:

[0164] Itaconic acid derived naphthalene type photocurable epoxy resin (IEN) 50 parts,

[0165] Itaconic acid derived biphenyl type light curing epoxy resin (IET) 50 parts,

[0166] Photoinitiator (2-isopropylthioxanthone) 3 parts.

[0167] The photosensitive solder resist inks prepared in Examples 1 to 5 were subjected to 395 nm ultraviolet light (25 mJ cm -2 ) The ink was light-cured for 3 minutes, and then further heat-cured at 150°C for 60 minutes to form a cured film. The cured film was cut into 0.3 cm × 3 cm rectangular strips and tested as samples. The performance comparison is shown in Table 1 below:

[0168] Table 1

[0169]

[0170] Through the above test data, it can be concluded that the effect of the change in the components of the photosensitive solder mask ink provided by the present invention on the curing resin Tan (δ) mainly depends on the following three factors: 1) The difference in steric hindrance caused by the binary aromatic skeleton inhibits the movement of the molecular chain (steric hindrance: tetramethylbiphenyl molecule>naphthalene molecule); 2) The increase in polar groups plays a positive role in improving the glass transition temperature of the UV-curable resin; 3) The glass transition temperature of the itaconic acid functionalized two-phase mixed resin is improved with the construction of the network cross-linking structure and the increase of its cross-linking density.

[0171] In addition, in the compounding of itaconic acid-derived naphthalene type photocurable epoxy resin and itaconic acid-derived biphenyl type photocurable epoxy resin, it was unexpectedly found that when the mass ratio of the two was a specific value (5:1), the cured sample had a significant improvement in the thermal mechanical properties, and the performance greatly surpassed the samples using only itaconic acid-derived naphthalene type photocurable epoxy resin or itaconic acid-derived biphenyl type photocurable epoxy resin as raw materials, indicating that in the actual use of the product of the present invention, better product performance can be achieved through further compounding technical means.

Claims

1. A photosensitive solder resist ink, characterized in that The raw materials mainly include: 83.33 parts of itaconic acid-derived naphthalene-type photocurable epoxy resin, 16.67 parts of itaconic acid-derived biphenyl type photocurable epoxy resin, 3 parts of photoinitiator; The itaconic acid-derived naphthalene-type photocurable epoxy resin and the itaconic acid-derived biphenyl-type photocurable epoxy resin are obtained by firstly subjecting a small molecule naphthalene-type epoxy compound or a small molecule biphenyl-type epoxy compound to a ring-opening reaction with itaconic acid, and then subjecting the compound to an esterification reaction with an unsaturated acid anhydride. The itaconic acid is added in a molar ratio of (1 to 1.2):1 to the epoxy group of the small molecule naphthalene epoxy compound or the small molecule biphenyl epoxy compound, and the unsaturated acid anhydride is added in a molar ratio of (1 to 4):1 to the epoxy group of the small molecule naphthalene epoxy compound or the small molecule biphenyl epoxy compound; The small molecule naphthalene epoxy compound is 1,6-naphthalene diglycidyl ether; The small molecule biphenyl type epoxy compound is 3,3'5,5'-tetramethylbiphenyl bisphenol diglycidyl ether; The unsaturated acid anhydride is itaconic anhydride; The photoinitiator is at least one of 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide, 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone, 2-hydroxy-4-(2-hydroxyethoxyphenyl)-2-methylpropiophenone, 2-isopropylthioxanthone, 2-hydroxy-2-methyl-1-phenylpropanone, benzoin ethyl ether, benzil dimethyl ketal, benzophenone / triethanolamine and benzophenone / acrylate active amine.

2. The photosensitive solder resist ink according to claim 1, characterized in that The preparation method of the itaconic acid-derived naphthalene type photocurable epoxy resin and the itaconic acid-derived biphenyl type photocurable epoxy resin mainly comprises the following steps: (1) In an air atmosphere, preheat the solvent to 70-90° C., add a small molecular naphthalene epoxy compound or a small molecular biphenyl epoxy compound and dissolve it, cool it to 50-60° C., add itaconic acid, then heat it to 70-80° C., add a ring-opening reaction catalyst and a polymerization inhibitor, then adjust the temperature to 100-120° C. and stir the reaction at this temperature for 10-15 hours to obtain an intermediate product; The catalyst for the ring-opening reaction includes one of triethylamine, triethanolamine, 4-dimethylaminopyridine, tetrabutylammonium bromide, tetramethylammonium chloride, N,N-dimethylbenzylamine and triphenylphosphine; (2) cooling the intermediate product obtained in step (1) to 70-80° C., then adding unsaturated acid anhydride and polymerization inhibitor, heating to 85-100° C. and stirring for reaction for 7-12 hours to prepare itaconic acid-derived naphthalene-type photocurable epoxy resin or itaconic acid-derived biphenyl-type photocurable epoxy resin; The polymerization inhibitor is at least one of hydroquinone, o-methyl hydroquinone, p-hydroxyanisole, p-benzoquinone and 2,6-di-tert-butyl-4-methylphenol.

3. The photosensitive solder resist ink according to claim 2, characterized in that: The solvent in step (1) is at least one of 2,2-diethoxyethyl 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 mass of the solvent: the mass of the small molecule naphthalene type epoxy compound or the small molecule biphenyl type epoxy compound is (0.5-1.5):

1.

4. The photosensitive solder resist ink according to claim 2, characterized in that: The amount of catalyst added for the ring-opening reaction in step (1) is 0.2 to 1 wt % of the small molecule naphthalene-type epoxy compound or the small molecule biphenyl-type epoxy compound.

5. The photosensitive solder resist ink according to claim 1, characterized in that The raw materials include by weight: 20 to 50 parts of filler, 1 to 25 parts of additives.

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