Highly heat-resistant and degradable photocurable resin containing spirocyclic diacetal structure and preparation method thereof

Abstract

The invention discloses a high heat-resistant and degradable photocurable resin containing a spiro biacetal structure and a preparation method thereof. Firstly, a high heat-resistant and degradable photocurable resin containing a spiro biacetal structure is provided. The photocurable epoxy resin is prepared by firstly reacting an aldehyde-containing lignin-derived structural monomer compound and pentaerythritol to obtain a spiro biacetal phenol resin, and then subjecting the spiro biacetal phenol resin to a ring-opening reaction with a dihydroxy epoxy compound to obtain a spiro biacetal-modified epoxy compound; then, the obtained spiro biacetal-modified epoxy compound is modified with an acrylic modifier and then subjected to an esterification reaction with an acid anhydride to obtain the high heat-resistant and degradable photocurable resin containing a spiro biacetal structure; secondly, an application of the photocurable epoxy resin as a raw material for high-performance photosensitive solder resist ink is provided.

Description

Technical Field

[0001] The present invention belongs to the technical field of photocurable resins, and relates to a highly heat-resistant and degradable photocurable resin containing a spirocyclic biacetal structure and a preparation method thereof, and particularly relates to a highly heat-resistant and degradable photocurable resin containing a spirocyclic biacetal structure and a preparation method thereof, and uses the resin as a raw material for high-performance photosensitive solder resist ink. Background Art

[0002] Degradability and sustainability are two of the most important cornerstones of contemporary chemistry and chemical product design. The development of high-performance, high-value-added chemicals based on renewable raw materials to replace non-renewable raw materials is at the core of these important initiatives and is also an effective means to alleviate the increasingly serious fossil energy crisis and environmental pollution problems. To date, two conventional strategies have been used to synthesize bio-based chemicals from biological resources: Ⅰ) introducing functional groups and special structural segments into the natural polymer backbone to generate versatile bio-based polymers for some advanced applications, such as photo-crosslinking and dynamic cross-linking materials; Ⅱ) utilizing various bio-based / natural chemicals, such as natural phenols, eugenol, and vanillin, for the direct synthesis and development of biopolymer / resin platforms. However, how to strike a balance between degradability and sustainability and high performance of bio-based polymer / resin platforms remains a severe challenge.

[0003] Generally speaking, thermosetting resins including epoxy resins, phenolic resins and acrylic resins have ideal thermal and mechanical properties, high heat resistance, and fascinating creep resistance due to the construction of cross-linked networks. Among them, epoxy resins and downstream materials are widely used as composite matrix, adhesives, and electronic packaging coatings as important industrial chemicals. They play an irreplaceable role in many applications, such as building solder mask layers in advanced printed circuit boards (PCBs). Unfortunately, since photo-cross-linked curing resins cannot be melted and degraded, it is difficult to recycle high-value metals and laminates through mild chemical means after the printed circuit board reaches the end of its service life. However, traditional methods for handling waste curing resins and coatings, such as strong mechanical crushing, incineration, landfill and corrosion, have the disadvantages of serious environmental pollution, energy consumption and low degradation efficiency.

[0004] Recently, many pioneering approaches have addressed this problem, namely, adding an unstable bond or a volatile connection structure to the backbone structure of the thermosetting network to impart degradability. To achieve this goal, some structures that are relatively weak under mild conditions, such as ester bonds, Schiff base connections, sulfonate connections, and acetal connections, have been creatively designed to establish some special connection systems. Nevertheless, the "seesaw" problem between high performance and excellent degradability of photocrosslinked networks remains prominent, because high heat resistance usually requires high crosslinking density, which is not conducive to degradability and practical application. Taking solder mask resin for printed circuit board ink as an example, UV-cured bio-based resins have photocrosslinked and thermal crosslinked networks, which impart excellent degradability while maintaining high heat resistance and photopolymerization performance, which is of great significance for reducing environmental impact and improving economic returns. Summary of the invention

[0005] In order to solve the problems in the above-mentioned prior art, the present invention provides a high heat-resistant, degradable photocurable resin containing a spirobiacetal structure and a preparation method thereof. The first invention object is to provide a high heat-resistant, degradable photocurable resin containing a spirobiacetal structure. The second invention object is to provide an application of the above-mentioned high heat-resistant, degradable photocurable resin containing a spirobiacetal structure as a raw material for high-performance 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 a highly heat-resistant and degradable photocurable resin containing a spirobiacetal structure, which is firstly obtained by subjecting an aldehyde-containing lignin-derived structural monomer compound and pentaerythritol to a diacetal reaction to obtain a spirobiacetal phenol resin, and then subjecting the spirobiacetal phenol resin to a ring-opening reaction with a dihydroxy epoxy compound to obtain a spirobiacetal-modified epoxy compound; then, the obtained spirobiacetal-modified epoxy compound is modified with an acrylic modifier and then subjected to an esterification reaction with an acid anhydride to obtain the highly heat-resistant and degradable photocurable resin containing a spirobiacetal structure;

[0008] The chemical structure formula of the aldehyde-containing lignin-derived structural monomer compound is as follows:

[0009]

[0010] Wherein, R=CH3, COOH, CH2OH, CN or CH2NH2.

[0011] In one preferred technical solution, the aldehyde-containing lignin-derived structural monomer compound is preferably commercially available vanillin (CAS: 121-33-5).

[0012] Herein, the aldehyde-containing lignin-derived structural monomer compound and pentaerythritol are reacted through a diacetal reaction to obtain a spirocyclic diacetal phenol resin, wherein the diacetal reaction related to pentaerythritol is a known reaction system that has been reported in existing literature in the technical field. Based on the known reaction system, when the aldehyde-containing lignin-derived structural monomer compound is selected as a raw material, those skilled in the art can obtain the reaction conditions according to the known reaction system and common knowledge in the art, for example, the aldehyde-containing lignin-derived structural monomer compound and pentaerythritol are dissolved in an organic solvent and reacted under the catalytic conditions of an acetal reaction catalyst.

[0013] In order to better illustrate the present invention and provide a preferred technical solution for reference, the aldehyde-containing lignin-derived structural monomer compound and pentaerythritol are subjected to a diacetal reaction to obtain a spirocyclic diacetal phenol resin. Under laboratory preparation conditions, the aldehyde-containing lignin-derived structural monomer compound and pentaerythritol are specifically dissolved in an organic solvent A, and an acetal reaction catalyst is added, and the reaction is stirred for at least 22 hours to obtain the spirocyclic diacetal phenol resin.

[0014] Among them, the organic solvent A is selected from the organic solvent commonly used in the diacetal reaction related to pentaerythritol, such as at least one of a dibasic acid 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.

[0015] The acetalization catalyst is selected from the acetalization catalyst commonly used in the diacetalization reaction of pentaerythritol, such as any one of p-toluenesulfonic acid, p-toluenesulfonyl chloride, p-toluenesulfonimide, p-toluenesulfonamide, and sodium p-toluenesulfonate.

[0016] Herein, the dihydroxy epoxy compound is selected from a conventional resin having two hydroxyl groups, such as any one of vanillin-derived diglycidyl ether, bisphenol A diglycidyl ether, 1,6-naphthalene diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, butylene glycol diglycidyl ether, glycerol diglycidyl ether, ethylene glycol glycidyl ether, propylene glycol glycidyl ether, butylene glycol glycidyl ether, ethylene glycol glycidyl ether, and butylene glycol glycidyl ether.

[0017] Furthermore, through comparative experiments, it was found that in the selection of the above-mentioned conventional dihydroxy epoxy compounds, their chemical structure formula will significantly affect the performance of the photocurable resin containing a spirocyclic diacetal structure finally prepared. Through the analysis of the rules summarized by the experimental results, difunctional epoxy compounds with a naphthyl ring group, a phenoxy group, and an aromatic ether group in the chemical structure are preferred.

[0018] In one of the technical solutions, it was found through comparative experiments that the dihydroxy epoxy compound is preferably at least one of vanillin-derived diglycidyl ether, bisphenol A diglycidyl ether, and 1,6-naphthalene diglycidyl ether. The high-performance photosensitive epoxy resin prepared therefrom has better comprehensive properties (such as high tensile strength, breaking strain and high voltage breakdown strength), as well as degradability under mild acid-catalyzed conditions.

[0019] In this article, the spiro biacetal phenol resin and the dihydroxy epoxy compound undergo a ring-opening reaction to obtain a spiro biacetal-modified epoxy compound, and the reaction mechanism is an acid-catalyzed ring-opening reaction of a phenolic hydroxyl group and an epoxy group, which is a known reaction system that has been reported in existing literature in the technical field. Based on the known reaction system, those skilled in the art can obtain the reaction conditions according to the known reaction system and common knowledge in the art, for example, adding the spiro biacetal phenol resin to the dihydroxy epoxy compound and reacting under the catalytic conditions of a ring-opening reaction catalyst A.

[0020] In order to better illustrate the present invention and provide a preferred technical scheme for reference, the spiro diacetal phenol resin and the dihydroxy epoxy compound undergo a ring-opening reaction to obtain a spiro diacetal-modified epoxy compound. Under laboratory preparation conditions, the spiro diacetal phenol resin is added to the dihydroxy epoxy compound, and a ring-opening reaction catalyst A and an antioxidant are added, and the reaction is carried out for at least 4 hours to obtain the spiro diacetal-modified epoxy compound.

[0021] The ring-opening reaction catalyst A is selected from the ring-opening reaction catalyst conventionally used in the acid-catalyzed ring-opening reaction of phenolic hydroxyl groups and epoxy groups, such as any one of tetrabutylammonium bromide, tetramethylammonium bromide, N,N-dimethylbenzylamine and triphenylphosphine.

[0022] The antioxidant may be any one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester (Antioxidant 1010), tri-tert-butyl hydroxyphenyl propane (Antioxidant 168), and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid (Antioxidant 3114).

[0023] In this article, the spirobiacetal-modified epoxy compound is modified with an acrylic modifier and then subjected to an esterification reaction with an acid anhydride. It is an acrylic modified resin system that is common knowledge in the field of photocurable resins. Based on the known modification system, those skilled in the art can obtain its reaction raw materials and reaction conditions according to the known modification system and common knowledge in the field, for example, dissolving the spirobiacetal-modified epoxy compound in an organic solvent B, adding an acrylic modifier to carry out a ring-opening reaction, and then carrying out an esterification reaction with an acid anhydride to prepare a highly heat-resistant, degradable photocurable resin containing a spirobiacetal structure.

[0024] The adding of acrylic modifier for ring-opening reaction includes adding ring-opening reaction catalyst B and polymerization inhibitor; the specific selection of organic solvent B, acrylic modifier, ring-opening reaction catalyst B and polymerization inhibitor can refer to the conventional selection in acrylic modified resin system.

[0025] In one of the preferred technical schemes, the organic solvent B is preferably at least one of a divalent 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.

[0026] In one of the preferred technical solutions, the acrylic modifier is preferably at least one of acrylic acid, 2-furan acrylic acid, 2-thiophene acrylic acid, 3-(3-pyridyl) acrylic acid, 2-acetamido acrylic acid, 4-imidazole acrylic acid, terephthalic acid, trans-3-indole acrylic acid, 2-fluoroacrylic acid, 2-benzyl acrylic acid, hydroxyethyl methacrylate, glycidyl methacrylate, acrylonitrile, and methacrylonitrile.

[0027] In one preferred technical solution, the ring-opening reaction catalyst B is preferably any one of triethylamine, triethanolamine, 4-dimethylaminopyridine, tetrabutylammonium bromide, tetramethylammonium chloride, N,N-dimethylbenzylamine and triphenylphosphine.

[0028] Among them, the esterification reaction is then carried out with an acid anhydride, including adding a polymerization inhibitor, but when the spirocyclic diacetal modified epoxy compound is modified by an acrylic modifier, when the polymerization inhibitor added is sufficient, the polymerization inhibitor may not be added; the specific selection of the acid anhydride and the polymerization inhibitor can refer to the conventional selection in the acrylic modified resin system. The acid anhydride is a saturated acid anhydride or unsaturated acid anhydride conventionally selected for preparing light-curing epoxy resins in the field. Those skilled in the art can select suitable acid anhydrides based on current process conditions or existing technical literature in the field, including monounsaturated acid anhydrides and polyunsaturated acid anhydrides, and can be selected according to actual process requirements or functional requirements.

[0029] In one of the technical solutions, the 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.

[0030] It should be noted that the aldehyde-containing lignin-derived structural monomer compound and pentaerythritol are first subjected to a diacetal reaction to obtain a spiro diacetal phenol resin, and then the spiro diacetal phenol resin is subjected to a ring-opening reaction with a dihydroxy epoxy compound to obtain a spiro diacetal-modified epoxy compound; the obtained spiro diacetal-modified epoxy compound is then modified with an acrylic modifier and then subjected to an esterification reaction with an acid anhydride. The amount of raw materials / materials added required for the above reactions and the amount of catalysts, solvents, and inhibitors added in the above technical scheme can all be carried out according to the amount required after the reaction is balanced, or can be the common knowledge in the technical field and the conventional amount of related catalysts and inhibitors.

[0031] In order to better illustrate the present invention and provide a technical solution for reference, the aldehyde-containing lignin-derived structural monomer compound is added in a molar ratio of (2 to 2.2):1 to pentaerythritol; the spirocyclic diacetal phenol resin is added in a molar ratio of 1:(2 to 2.2) to the dihydroxy epoxy compound; the spirocyclic diacetal-modified epoxy compound is added in a molar ratio of 1:(2 to 2.2) to the acrylic modifier, and the molar ratio to the anhydride group of the acid anhydride is 1:(1 to 4).

[0032] In one of the technical solutions, the raw materials 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 existing technology 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 may include fillers and / or additives conventionally used in epoxy resins, or may not include them.

[0033] One of the inventive points of the present invention is that a rigid spiro-bisacetal diphenol trigger is constructed using an aldehyde-containing lignin-derived structural monomer compound (such as vanillin) as a raw material, and an acid-catalyzed ring-opening reaction is performed with a dihydroxy epoxy compound to obtain a functionalized, degradable, heat-resistant spiro-bisacetal-modified epoxy compound, and on the basis of these spiro-bisacetal-modified epoxy compounds, two epoxy groups per molecule are used to perform a subsequent ring-opening reaction with an acrylic modifier, and finally an esterification reaction is performed with an unsaturated acid anhydride to obtain a high heat-resistant, degradable photocurable resin containing a spiro-bisacetal structure. Experiments have found that spiro-bisacetal-modified epoxy compounds participate in the ring-opening reaction, and will not be affected by organic acids (such as propylene and tetrahydrophthalic anhydride) to cause the spiro-bisacetal to degrade. It is worth noting that the spiro-bisacetal-modified epoxy compound has two epoxy groups per molecule and secondary hydroxyl groups produced by acrylic acid, which will vary depending on the selection of dihydroxy epoxy compounds. In further optimization, in order to maximize the photocuring efficiency, curing crosslinking density and resin glass transition temperature, the secondary hydroxyl groups produced are completely reacted by the anhydride. The photocurable resin with a spirocyclic diacetal structure provided in the technical solution of the present invention can have significant degradation characteristics under weak acid catalysis. From the technical level of designing and synthesizing photocurable coatings for electronic packaging applications, a new strategy and approach is provided to overcome the "seesaw" problem between high performance and degradability in the photocrosslinking network.

[0034] However, it should be noted that the experiment found that the structural differences between the photocurable resins containing spirocyclic diacetal structures have different requirements for acid degradation conditions. In the comparative experiment, the photocurable resin synthesized without adding dihydroxy epoxy compounds and the photocurable resin synthesized when the dihydroxy epoxy compound is selected as 1,6-naphthalene diglycidyl ether were used to prepare the solder mask ink. The degradation test was compared and it was found that the acid degradation condition of the solder mask ink prepared when the dihydroxy epoxy compound is selected as 1,6-naphthalene diglycidyl ether after curing was 0.3M HCl solution (acetone / water = 9 / 1, v / v), while the solder mask ink as a control sample (without adding dihydroxy epoxy compounds) can be degraded under milder acid catalysis conditions after curing, that is, 0.1M HCl solution (the solution is acetone / water = 9 / 1, v / v). This is mainly attributed to the reaction of spirobisacetal diphenol triggers with 1,6-naphthalene diglycidyl ether, which produces 4 secondary hydroxyl groups after acrylic acid modification to react with anhydride, while spirobisacetal epoxy resin only forms 2 secondary hydroxyl groups when no dihydroxy epoxy compound is added. In contrast, the higher double bond density has a positive effect on the photocuring efficiency, curing crosslinking density, and glass transition temperature of the spirobisacetal system, and can more appropriately improve its weather resistance, avoid its direct degradation in a weak acid environment, and have no significant effect on its recycling and degradation.

[0035] The above technical scheme provides a highly heat-resistant, degradable photocurable resin containing a spirocyclic biacetal structure, and gives its main raw material components and reaction types. Based on the common knowledge in the art, those skilled in the art can know the conventional process of its chemical reaction and the conventional modification preparation method of photosensitive epoxy resin, thereby preparing the highly heat-resistant, degradable photocurable resin containing a spirocyclic biacetal structure described in the present invention. Therefore, the following preparation method only provides a preferred technical scheme for reference, and does not mean to limit / specify the technical scheme of the present invention, nor is it unique.

[0036] In order to better illustrate the present invention and provide a preferred technical solution, the preparation method of the above-mentioned high heat-resistant and degradable photocurable resin containing a spirocyclic diacetal structure mainly comprises the following steps:

[0037] (1) In an air atmosphere, preheating an organic solvent A to 50-60° C., adding an aldehyde-containing lignin-derived structural monomer compound and pentaerythritol to dissolve them, then heating to 85-95° C., adding an acetal reaction catalyst, maintaining the temperature at 85-95° C., stirring and reacting for 22-26 hours, and obtaining a spirobisacetal phenol resin solution;

[0038] (2) pouring the spirocyclic diacetal phenol resin solution obtained in step (1) into ice water until the reaction solution is completely precipitated, and filtering to obtain a spirocyclic diacetal phenol resin solid powder;

[0039] (3) preheating the dihydroxy epoxy compound to a liquid state under air atmosphere, adding the spirobisacetal phenol resin solid powder obtained in step (2), a ring-opening reaction catalyst A and an antioxidant, and then heating to 95 to 105° C. and reacting for 4 to 6 hours to obtain a spirobisacetal-modified epoxy compound;

[0040] (4) In an air atmosphere, preheating the organic solvent B to 75-95° C., adding the spirocyclic biacetal-modified epoxy compound obtained in step (3) and dissolving it, cooling the mixture to 55-65° C., then adding an acrylic modifier, a ring-opening reaction catalyst B and a polymerization inhibitor, and mixing the mixture. The mixture is heated to 100-110° C. and stirred for reaction for 12-16 hours. After the time is up, the temperature is adjusted to 70-90° C., the polymerization inhibitor and anhydride are added and mixed, and the temperature is adjusted to 95-105° C. and stirred for reaction for 10-12 hours to prepare a highly heat-resistant, degradable photocurable resin containing a spirocyclic biacetal structure.

[0041] In one of the technical solutions, the mass of the organic solvent A in step (1): the mass of the aldehyde-containing lignin-derived structural monomer compound = (2-6): 1.

[0042] In one of the technical solutions, the amount of the acetalization reaction catalyst added in step (1) is 0.5-2.5 wt % of the aldehyde-containing lignin-derived structural monomer.

[0043] In one of the technical solutions, the amount of the ring-opening reaction catalyst A added in step (3) is 0.5 to 2.5 wt % of the spirobisacetal phenol resin solid powder.

[0044] In one of the technical solutions, the amount of the antioxidant added in step (3) is 0.2 to 1 wt % of the spirobisacetal phenol resin solid powder.

[0045] In one of the technical solutions, the mass of the organic solvent B in step (4): the mass of the spirocyclic diacetal-modified epoxy compound = (0.5-1.5): 1.

[0046] In one of the technical solutions, the amount of the ring-opening reaction catalyst B added in step (4) is 0.2 to 1 wt % of the spirocyclic diacetal-modified epoxy compound.

[0047] In one of the technical solutions, the amount of the polymerization inhibitor added in step (4) is 0.1 to 0.5 wt % of the spirocyclic diacetal-modified epoxy compound.

[0048] Herein, the stirring reaction 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 state of 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.

[0049] On the other hand, based on the above-mentioned high heat-resistant and degradable photocurable resin containing a spirocyclic biacetal structure, the present invention also provides a high-performance photosensitive solder resist ink using the above-mentioned photocurable epoxy resin as a main component, and its raw materials mainly include, by weight:

[0050] 100 parts of a highly heat-resistant, degradable photocurable resin containing a spirocyclic diacetal structure,

[0051] 1 to 5 parts of photoinitiator.

[0052] 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.

[0053] 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.

[0054] In one preferred technical solution, the high-performance photosensitive solder resist ink further comprises, by weight:

[0055] 20 to 50 parts of filler,

[0056] 1 to 25 parts of additives.

[0057] 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.

[0058] 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.

[0059] The preparation method of the high-performance photosensitive solder resist ink can be prepared by mixing all 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 high-performance photosensitive solder resist ink.

[0060] 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, but since carboxyl groups are introduced into the alkali-soluble photocurable epoxy resin modified with acetylene-containing reactive monomers, the unexposed portion will dissolve in an alkaline aqueous solution, so alkaline development is preferably performed. 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.

[0061] After development, it is preferred that a heat treatment be performed at about 120 to 160° C. for 1 hour to further heat cure the photocured coating film.

[0062] Generally, the high-performance 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 and drying on a film such as PET in advance.

[0063] The present invention has the following beneficial effects:

[0064] (1) The present invention provides a highly heat-resistant, biodegradable photocurable resin containing a spiro diacetal structure, which is first obtained by reacting a lignin-derived structural monomer compound containing an aldehyde group with pentaerythritol through a diacetal reaction to obtain a spiro diacetal phenol resin, and then introducing a structural unit with acid-catalyzed degradation properties into the diacetal reaction, and then subjecting the spiro diacetal phenol resin to a ring-opening reaction with a dihydroxy epoxy compound to obtain a spiro diacetal-modified epoxy compound, and introducing a functionalized epoxy structure at both ends of the compound containing the spiro diacetal trigger through an acid-catalyzed reaction between a phenolic hydroxyl group and an epoxy group, so that the compound has multiple reaction sites and a rigid structure imparted by the dihydroxy epoxy structure itself, which has a significant promoting effect on the mechanical properties and other properties of the photocurable resin finally obtained.

[0065] (2) In the present invention, by specifically selecting the dihydroxy epoxy compound, it is possible to design different aromatic and non-aromatic units at both ends of the spirocyclic diacetal-modified epoxy compound, thereby imparting high cross-linking and heat-resistant characteristics and excellent anti-mechanical damping structure in the structure, thereby achieving high tensile strength and tensile strain.

[0066] (3) In the present invention, by introducing a spirocyclic diacetal structure with acid-catalyzed degradation, the highly cross-linked network is endowed with photo- and thermal-reversible properties. Without affecting the thermophysical properties of the cross-linked network, the photocurable resin is degradable under appropriate acidic conditions, while being non-degradable under inappropriate acidic conditions.

[0067] (4) In one of the technical solutions, a large number of hydroxyl groups are introduced through the ring-opening reaction, and a higher proportion of unsaturated acid anhydride is also added. A large number of unsaturated double bonds and carboxyl groups are introduced by the esterification reaction of hydroxyl groups and acid anhydride, thereby ensuring a high double bond density of the obtained high-performance photosensitive epoxy resin. Therefore, the film has a higher glass transition temperature after curing.

[0068] (5) In the present invention, a large number of carboxyl groups are introduced by reacting anhydride with hydroxyl groups, so that the product has good alkali developing performance, and can be quickly and completely detached by directly immersing in concentrated alkali solution without damaging the substrate.

[0069] (6) The high-performance 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, resistance to voltage breakdown, chemical resistance, electroless gold plating resistance, electroless tin plating resistance, and electrical insulation properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 Schematic diagram of the synthesis route of the intermediate product obtained in step (3) of Synthesis Example 1, Synthesis Example 2 and Comparative Synthesis Example 1 of the present invention.

[0071] Figure 2 The figure is a schematic diagram of the synthesis route from the intermediate product obtained in step (3) to the final product in Synthesis Example 1, Synthesis Example 2 and Comparative Synthesis Example 1 of the present invention.

[0072] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the spirobisacetal phenol resin obtained in step (2) of Synthesis Example 1 of the present invention.

[0073] Figure 4 The hydrogen nuclear magnetic resonance spectra of the intermediate product after acrylic acid modification in step (4) of comparative synthesis example 1 of the present invention and the final product obtained in step (4) are shown.

[0074] Figure 5 The carbon NMR spectrum of the intermediate product obtained in step (3) of Synthesis Example 1 of the present invention.

[0075] Figure 6 The carbon NMR spectrum of the intermediate product obtained in step (3) of Synthesis Example 2 of the present invention.

[0076] Figure 7This is the hydrogen nuclear magnetic spectrum of the final product of Synthesis Example 2 of the present invention.

[0077] Figure 8 This is the hydrogen nuclear magnetic spectrum of the final product of Synthesis Example 1 of the present invention.

[0078] Fig. 9 The following is a comparison chart of tan(δ), storage modulus, loss modulus, and stress-strain curves of the photosensitive solder resist inks prepared in Example 1, Example 2, and Comparative Example 1 of the present invention after curing.

[0079] Fig.10 Comparative photos of the degradation test results of the photosensitive solder resist ink prepared in Example 1 of the present invention after curing.

[0080] Fig.11 This is a comparison chart of the DC voltage breakdown strength and shape factor of the photosensitive solder resist inks prepared in Example 1, Example 2 and Comparative Example 1 of the present invention after curing. DETAILED DESCRIPTION

[0081] 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.

[0082] On the one hand, the present invention provides a highly heat-resistant and degradable photocurable resin containing a spirobiacetal structure, which is firstly obtained by subjecting an aldehyde-containing lignin-derived structural monomer compound and pentaerythritol to a diacetal reaction to obtain a spirobiacetal phenol resin, and then subjecting the spirobiacetal phenol resin to a ring-opening reaction with a dihydroxy epoxy compound to obtain a spirobiacetal-modified epoxy compound; then, the obtained spirobiacetal-modified epoxy compound is modified with an acrylic modifier and then subjected to an esterification reaction with an acid anhydride to obtain the highly heat-resistant and degradable photocurable resin containing a spirobiacetal structure;

[0083] The chemical structure formula of the aldehyde-containing lignin-derived structural monomer compound is as follows:

[0084]

[0085] Wherein, R=CH3, COOH, CH2OH, CN or CH2NH2.

[0086] In one preferred embodiment, the aldehyde-containing lignin-derived structural monomer compound is preferably commercially available vanillin (CAS: 121-33-5).

[0087] Herein, the aldehyde-containing lignin-derived structural monomer compound and pentaerythritol are reacted through a diacetal reaction to obtain a spirocyclic diacetal phenol resin, wherein the diacetal reaction related to pentaerythritol is a known reaction system that has been reported in existing literature in the technical field. Based on the known reaction system, when the aldehyde-containing lignin-derived structural monomer compound is selected as a raw material, those skilled in the art can obtain the reaction conditions according to the known reaction system and common knowledge in the art, for example, the aldehyde-containing lignin-derived structural monomer compound and pentaerythritol are dissolved in an organic solvent and reacted under the catalytic conditions of an acetal reaction catalyst.

[0088] In order to better illustrate the present invention and provide a preferred embodiment for reference, the aldehyde-containing lignin-derived structural monomer compound and pentaerythritol are subjected to a diacetal reaction to obtain a spirocyclic diacetal phenol resin. Under laboratory preparation conditions, the aldehyde-containing lignin-derived structural monomer compound and pentaerythritol are specifically dissolved in an organic solvent A, and an acetal reaction catalyst is added, and the reaction is stirred for at least 22 hours to obtain the spirocyclic diacetal phenol resin.

[0089] In one embodiment, the organic solvent A is selected from an organic solvent conventionally used in the diacetal reaction related to pentaerythritol, such as at least one of a dibasic acid 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.

[0090] In one embodiment, the acetalization reaction catalyst is selected from the acetalization reaction catalyst conventionally used in the diacetal reaction related to pentaerythritol, such as any one of p-toluenesulfonic acid, p-toluenesulfonyl chloride, p-toluenesulfonimide, p-toluenesulfonamide, and sodium p-toluenesulfonate.

[0091] Herein, the dihydroxy epoxy compound is selected from a conventional resin having two hydroxyl groups. In one embodiment, for example, any one of vanillin-derived diglycidyl ether, bisphenol A diglycidyl ether, 1,6-naphthalene diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, butylene glycol diglycidyl ether, glycerol diglycidyl ether, ethylene glycol glycidyl ether, propylene glycol glycidyl ether, butylene glycol glycidyl ether, ethylene glycol glycidyl ether, and butylene glycol glycidyl ether is selected.

[0092] Furthermore, through comparative experiments, it was found that in the selection of the above-mentioned conventional dihydroxy epoxy compounds, their chemical structure formula will significantly affect the performance of the photocurable resin containing a spirocyclic diacetal structure finally prepared. Through the analysis of the rules summarized by the experimental results, difunctional epoxy compounds with a naphthyl ring group, a phenoxy group, and an aromatic ether group in the chemical structure are preferred.

[0093] In one of the preferred embodiments, it is found through comparative experiments that the dihydroxy epoxy compound is preferably at least one of vanillin-derived diglycidyl ether, bisphenol A diglycidyl ether, and 1,6-naphthalene diglycidyl ether, and the high-performance photosensitive epoxy resin prepared therefrom has better comprehensive properties (such as high tensile strength, breaking strain and high voltage breakdown strength), as well as degradability under mild acid-catalyzed conditions.

[0094] In this article, the spiro biacetal phenol resin and the dihydroxy epoxy compound undergo a ring-opening reaction to obtain a spiro biacetal-modified epoxy compound, and the reaction mechanism is an acid-catalyzed ring-opening reaction of a phenolic hydroxyl group and an epoxy group, which is a known reaction system that has been reported in existing literature in the technical field. Based on the known reaction system, those skilled in the art can obtain the reaction conditions according to the known reaction system and common knowledge in the art, for example, adding the spiro biacetal phenol resin to the dihydroxy epoxy compound and reacting under the catalytic conditions of a ring-opening reaction catalyst A.

[0095] In order to better illustrate the present invention and provide a preferred embodiment for reference, the spiro diacetal phenol resin and the dihydroxy epoxy compound undergo a ring-opening reaction to obtain a spiro diacetal-modified epoxy compound. Under laboratory preparation conditions, specifically, the spiro diacetal phenol resin is added to the dihydroxy epoxy compound, and a ring-opening reaction catalyst A and an antioxidant are added, and the reaction is carried out for at least 4 hours to obtain the spiro diacetal-modified epoxy compound.

[0096] The ring-opening reaction catalyst A is a ring-opening reaction catalyst conventionally used in the acid-catalyzed ring-opening reaction of phenolic hydroxyl groups and epoxy groups. In one embodiment, for example, any one of tetrabutylammonium bromide, tetramethylammonium bromide, N,N-dimethylbenzylamine and triphenylphosphine is selected.

[0097] In one embodiment, the antioxidant is any one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester (antioxidant 1010), tri-tert-butyl hydroxyphenyl propane (antioxidant 168), and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid (antioxidant 3114).

[0098] In this article, the spirobiacetal-modified epoxy compound is modified with an acrylic modifier and then subjected to an esterification reaction with an acid anhydride. It is an acrylic modified resin system that is common knowledge in the field of photocurable resins. Based on the known modification system, those skilled in the art can obtain its reaction raw materials and reaction conditions according to the known modification system and common knowledge in the field, for example, dissolving the spirobiacetal-modified epoxy compound in an organic solvent B, adding an acrylic modifier to carry out a ring-opening reaction, and then carrying out an esterification reaction with an acid anhydride to prepare a highly heat-resistant, degradable photocurable resin containing a spirobiacetal structure.

[0099] The adding of acrylic modifier for ring-opening reaction includes adding ring-opening reaction catalyst B and polymerization inhibitor; the specific selection of organic solvent B, acrylic modifier, ring-opening reaction catalyst B and polymerization inhibitor can refer to the conventional selection in acrylic modified resin system.

[0100] In one preferred embodiment, the organic solvent B is preferably at least one of a divalent 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.

[0101] In one preferred embodiment, the acrylic modifier is preferably at least one of acrylic acid, 2-furan acrylic acid, 2-thiophene acrylic acid, 3-(3-pyridyl) acrylic acid, 2-acetamido acrylic acid, 4-imidazole acrylic acid, terephthalic acid, trans-3-indole acrylic acid, 2-fluoroacrylic acid, 2-benzyl acrylic acid, hydroxyethyl methacrylate, glycidyl methacrylate, acrylonitrile, and methacrylonitrile.

[0102] In one preferred embodiment, the ring-opening reaction catalyst B is preferably any one of triethylamine, triethanolamine, 4-dimethylaminopyridine, tetrabutylammonium bromide, tetramethylammonium chloride, N,N-dimethylbenzylamine and triphenylphosphine.

[0103] Among them, the esterification reaction is then carried out with an acid anhydride, including adding a polymerization inhibitor, but when the spirocyclic diacetal modified epoxy compound is modified by an acrylic modifier, when the polymerization inhibitor added is sufficient, the polymerization inhibitor may not be added; the specific selection of the acid anhydride and the polymerization inhibitor can refer to the conventional selection in the acrylic modified resin system. The acid anhydride is a saturated acid anhydride or unsaturated acid anhydride conventionally selected for preparing light-curing epoxy resins in the field. Those skilled in the art can select suitable acid anhydrides based on current process conditions or existing technical literature in the field, including monounsaturated acid anhydrides and polyunsaturated acid anhydrides, and can be selected according to actual process requirements or functional requirements.

[0104] In one embodiment, the 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.

[0105] It should be noted that the aldehyde-containing lignin-derived structural monomer compound and pentaerythritol are first subjected to a diacetal reaction to obtain a spiro diacetal phenol resin, and then the spiro diacetal phenol resin is subjected to a ring-opening reaction with a dihydroxy epoxy compound to obtain a spiro diacetal-modified epoxy compound; the obtained spiro diacetal-modified epoxy compound is then modified with an acrylic modifier and then subjected to an esterification reaction with an acid anhydride. The amount of raw materials / materials added required for the above reactions and the amount of catalysts, solvents, and inhibitors added in the above technical scheme can all be carried out according to the amount required after the reaction is balanced, or can be the common knowledge in the technical field and the conventional amount of related catalysts and inhibitors.

[0106] In order to better illustrate the present invention and provide an embodiment for reference, the aldehyde-containing lignin-derived structural monomer compound is added in a molar ratio of (2 to 2.2):1 with pentaerythritol; the spirocyclic diacetal phenol resin is added in a molar ratio of 1:(2 to 2.2) with the dihydroxy epoxy compound; the spirocyclic diacetal-modified epoxy compound is added in a molar ratio of 1:(2 to 2.2) with the acrylic modifier, and in a molar ratio of 1:(1 to 4) with the anhydride group of the acid anhydride.

[0107] In one embodiment, the raw material 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. Note that the raw material may include fillers and / or additives conventionally used in epoxy resins, or may not include them.

[0108] One of the inventive points of the present invention is that a rigid spiro-bisacetal diphenol trigger is constructed using an aldehyde-containing lignin-derived structural monomer compound (such as vanillin) as a raw material, and an acid-catalyzed ring-opening reaction is performed with a dihydroxy epoxy compound to obtain a functionalized, degradable, heat-resistant spiro-bisacetal-modified epoxy compound, and on the basis of these spiro-bisacetal-modified epoxy compounds, two epoxy groups per molecule are used to perform a subsequent ring-opening reaction with an acrylic modifier, and finally an esterification reaction is performed with an unsaturated acid anhydride to obtain a high heat-resistant, degradable photocurable resin containing a spiro-bisacetal structure. Experiments have found that spiro-bisacetal-modified epoxy compounds participate in the ring-opening reaction, and will not be affected by organic acids (such as propylene and tetrahydrophthalic anhydride) to cause the spiro-bisacetal to degrade. It is worth noting that the spiro-bisacetal-modified epoxy compound has two epoxy groups per molecule and secondary hydroxyl groups produced by acrylic acid, which will vary depending on the selection of dihydroxy epoxy compounds. In further optimization, in order to maximize the photocuring efficiency, curing crosslinking density and resin glass transition temperature, the secondary hydroxyl groups produced are completely reacted by the anhydride. The photocurable resin with a spirocyclic diacetal structure provided in the technical solution of the present invention can have significant degradation characteristics under weak acid catalysis. From the technical level of designing and synthesizing photocurable coatings for electronic packaging applications, a new strategy and approach is provided to overcome the "seesaw" problem between high performance and degradability in the photocrosslinking network.

[0109] However, it should be noted that the experiment found that the structural differences between the photocurable resins containing spirocyclic diacetal structures have different requirements for acid degradation conditions. In the comparative experiment, the photocurable resin synthesized without adding dihydroxy epoxy compounds and the photocurable resin synthesized when the dihydroxy epoxy compound is selected as 1,6-naphthalene diglycidyl ether were used to prepare the solder mask ink. The degradation test was compared and it was found that the acid degradation condition of the solder mask ink prepared when the dihydroxy epoxy compound is selected as 1,6-naphthalene diglycidyl ether after curing was 0.3M HCl solution (acetone / water = 9 / 1, v / v), while the solder mask ink as a control sample (without adding dihydroxy epoxy compounds) can be degraded under milder acid catalysis conditions after curing, that is, 0.1M HCl solution (the solution is acetone / water = 9 / 1, v / v). This is mainly attributed to the reaction of spirobisacetal diphenol triggers with 1,6-naphthalene diglycidyl ether, which produces 4 secondary hydroxyl groups after acrylic acid modification to react with anhydride, while spirobisacetal epoxy resin only forms 2 secondary hydroxyl groups when no dihydroxy epoxy compound is added. In contrast, the higher double bond density has a positive effect on the photocuring efficiency, curing crosslinking density, and glass transition temperature of the spirobisacetal system, and can more appropriately improve its weather resistance, avoid its direct degradation in a weak acid environment, and have no significant effect on its recycling and degradation.

[0110] The above technical scheme provides a highly heat-resistant, degradable photocurable resin containing a spirocyclic biacetal structure, and gives its main raw material components and reaction types. Based on the common knowledge in the art, those skilled in the art can know the conventional process of its chemical reaction and the conventional modification preparation method of photosensitive epoxy resin, thereby preparing the highly heat-resistant, degradable photocurable resin containing a spirocyclic biacetal structure described in the present invention. Therefore, the following preparation method only provides a preferred technical scheme for reference, and does not mean to limit / specify the technical scheme of the present invention, nor is it unique.

[0111] In order to better illustrate the present invention and provide a preferred embodiment, the preparation method of the above-mentioned high heat-resistant and degradable photocurable resin containing a spirocyclic diacetal structure mainly comprises the following steps:

[0112] (1) In an air atmosphere, preheating an organic solvent A to 50-60° C., adding an aldehyde-containing lignin-derived structural monomer compound and pentaerythritol to dissolve them, then heating to 85-95° C., adding an acetal reaction catalyst, maintaining the temperature at 85-95° C., stirring and reacting for 22-26 hours, and obtaining a spirobisacetal phenol resin solution;

[0113] (2) pouring the spirocyclic diacetal phenol resin solution obtained in step (1) into ice water until the reaction solution is completely precipitated, and filtering to obtain a spirocyclic diacetal phenol resin solid powder;

[0114] (3) preheating the dihydroxy epoxy compound to a liquid state under air atmosphere, adding the spirobisacetal phenol resin solid powder obtained in step (2), a ring-opening reaction catalyst A and an antioxidant, and then heating to 95 to 105° C. and reacting for 4 to 6 hours to obtain a spirobisacetal-modified epoxy compound;

[0115] (4) In an air atmosphere, preheating the organic solvent B to 75-95° C., adding the spirocyclic biacetal-modified epoxy compound obtained in step (3) and dissolving it, cooling the mixture to 55-65° C., then adding an acrylic modifier, a ring-opening reaction catalyst B and a polymerization inhibitor, and mixing the mixture. The mixture is heated to 100-110° C. and stirred for reaction for 12-16 hours. After the time is up, the temperature is adjusted to 70-90° C., the polymerization inhibitor and anhydride are added and mixed, and the temperature is adjusted to 95-105° C. and stirred for reaction for 10-12 hours to prepare a highly heat-resistant, degradable photocurable resin containing a spirocyclic biacetal structure.

[0116] In one embodiment, the mass of the organic solvent A in step (1): the mass of the aldehyde-containing lignin-derived structural monomer compound = (2-6): 1.

[0117] In one embodiment, the amount of the acetalization reaction catalyst added in step (1) is 0.5-2.5 wt % of the aldehyde-containing lignin-derived structural monomer.

[0118] In one embodiment, the amount of the ring-opening reaction catalyst A added in step (3) is 0.5 to 2.5 wt % of the spirobisacetal phenol resin solid powder.

[0119] In one embodiment, the amount of the antioxidant added in step (3) is 0.2 to 1 wt % of the spirobisacetal phenol resin solid powder.

[0120] In one embodiment, the mass of the organic solvent B in step (4) : the mass of the spirocyclic diacetal-modified epoxy compound = (0.5-1.5): 1.

[0121] In one embodiment, the amount of the ring-opening reaction catalyst B added in step (4) is 0.2 to 1 wt % of the spirocyclic diacetal-modified epoxy compound.

[0122] In one embodiment, the amount of the polymerization inhibitor added in step (4) is 0.1 to 0.5 wt % of the spirobisacetal-modified epoxy compound.

[0123] Herein, the stirring reaction 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 state of 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.

[0124] On the other hand, based on the above-mentioned high heat-resistant and degradable photocurable resin containing a spirocyclic biacetal structure, the present invention also provides a high-performance photosensitive solder resist ink using the above-mentioned photocurable epoxy resin as a main component, and its raw materials mainly include, by weight:

[0125] 100 parts of a highly heat-resistant, degradable photocurable resin containing a spirocyclic diacetal structure,

[0126] 1 to 5 parts of photoinitiator.

[0127] 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.

[0128] 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.

[0129] In one preferred embodiment, the high performance photosensitive solder resist ink further comprises, by weight:

[0130] 20 to 50 parts of filler,

[0131] 1 to 25 parts of additives.

[0132] 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.

[0133] 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.

[0134] The preparation method of the high-performance photosensitive solder resist ink can be prepared by mixing all 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 high-performance photosensitive solder resist ink.

[0135] 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, but since carboxyl groups are introduced into the alkali-soluble photocurable epoxy resin modified with acetylene-containing reactive monomers, the unexposed portion will dissolve in an alkaline aqueous solution, so alkaline development is preferably performed. 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.

[0136] After development, it is preferred that a heat treatment be performed at about 120 to 160° C. for 1 hour to further heat cure the photocured coating film.

[0137] Generally, the high-performance 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 and drying on a film such as PET in advance.

[0138] 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.

[0139] Example

[0140] 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.

[0141] 1. Raw materials

[0142] Vanillin and pentaerythritol were purchased from Sinopharm Chemical Reagent Co., Ltd.

[0143] Bisphenol A diglycidyl ether and epichlorohydrin were purchased from Aladdin Reagent (Shanghai) Co., Ltd.

[0144] 1,6-naphthalene diglycidyl ether (NDE) was purchased from DIC Corporation (Tokyo, Japan).

[0145] Hydroquinone (HQ), triphenylphosphine (TPP), and diethylene glycol ethyl ether acetate (DCAC) were from Huaxia Reagent Co., Ltd. (Chengdu, China).

[0146] Acrylic acid (AA), tetrahydrophthalic anhydride (THPA), p-toluenesulfonic acid and photoinitiator 2-isopropylthioxanthone (ITX) were provided by Sinopharm Chemical Reagent Co., Ltd.

[0147] 2. Test methods

[0148] 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.

[0149] For the degradation test, the cured samples were cut into strips (30 mm × 10 mm × 0.03 mm) and tested at 45°C using 0.1, 0.3, 0.5, 1.0, and 1.5 M HCl solutions (acetone / water = 9 / 1, v / v).

[0150] Dynamic mechanical thermal analyzer (DMTA, TAInstrumentsQ850) was used to test stress-strain curves and glass transition temperature in tensile mode. Stress-strain curve measurement: The cured sample (30 mm × 3 mm × 0.03 mm) was balanced at 25 °C and 0.1 N preload, and the load force was increased at a rate of 0.2 N / min. In addition, in tensile mode and 0.01 N preload, the load force was increased at a rate of 5 °C / min. -1 The tensile velocity is used to measure the stability of the sample as it changes with temperature.

[0151] 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 0.05 to 0.1 mm.

[0152] 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.

[0153] Synthesis example 1

[0154] This synthesis example provides a method for preparing a naphthalene-type biodegradable, light-cured epoxy resin derived from a spirocyclic double-locked structure, which mainly includes the following steps:

[0155] (1) In an air atmosphere, preheat the solvent diethylene glycol ethyl ether acetate to 55° C., add vanillin and pentaerythritol to dissolve them, then heat to 90° C., add acetal reaction catalyst p-toluenesulfonic acid, maintain the temperature at 90° C., stir and react for 24 hours to obtain a spirobisacetal phenol resin solution;

[0156] The molar ratio of vanillin to pentaerythritol is 2:1;

[0157] The acetalization reaction catalyst is added in an amount of 2.5 wt% of vanillin;

[0158] The mass of the solvent diethylene glycol ethyl ether acetate: the mass of vanillin = 4:1

[0159] (2) pouring the spirobisacetal phenol resin (2,2'-[2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl]dimethoxyphenol) solution obtained in step (1) into ice water (4°C) until the reaction solution is completely precipitated, filtering through a Buchner funnel, washing with deionized water, and drying in an oven at 50°C to obtain an intermediate product, spirobisacetal phenol resin solid powder, named VP;

[0160] (3) In an air atmosphere, 1,6-naphthalene diglycidyl ether is preheated to 75° C. to be in a low-viscosity liquid state, and the spirobisacetal phenol resin solid powder (VP) obtained in step (2), tetrabutylammonium bromide and antioxidant 1010 are added, and the temperature is then raised to 100° C. and reacted for 4 hours to obtain a spirobisacetal-modified epoxy compound, named VPNE;

[0161] The molar ratio of the spirobisacetal phenol resin solid powder (VP) to 1,6-naphthalene diglycidyl ether is 1:2;

[0162] The tetrabutylammonium bromide is added in an amount of 1wt% of the spirocyclic bisacetal phenol resin solid powder;

[0163] The antioxidant 1010 is added in an amount of 0.2 wt % of the spirobisacetal phenol resin solid powder;

[0164] (4) In an air atmosphere, preheat the solvent diethylene glycol ethyl ether acetate to 80° C., add the spirocyclic biacetal-modified epoxy compound (VPNE) obtained in step (3) and dissolve it, cool it to 60° C., then add acrylic acid, triphenylphosphine and hydroquinone to mix, and then heat it to 105° C. and stir to react for 14 hours. After the time is up, adjust the temperature to 80° C., add hydroquinone and tetrahydrophthalic anhydride to mix, and then adjust the temperature to 100° C. and stir to react for 10 to 12 hours to prepare a high heat-resistant, degradable photocurable resin containing a spirocyclic biacetal structure, which is named P-VPNE;

[0165] The spirocyclic diacetal modified epoxy compound is added in a molar ratio of 1:2 to acrylic acid and in a molar ratio of 1:4 to the anhydride group of tetrahydrophthalic anhydride;

[0166] The amount of triphenylphosphine added is 0.8 wt % of the spirocyclic diacetal-modified epoxy compound;

[0167] The amount of hydroquinone added each time is 0.4wt% of the spirocyclic diacetal-modified epoxy compound;

[0168] The mass of the solvent diethylene glycol ethyl ether acetate: the mass of the spirocyclic diacetal modified epoxy compound = 1:1.

[0169] Synthesis example 2

[0170] This synthesis example refers to the preparation method of synthesis example 1, except that in step (3), 1,6-naphthalene diglycidyl ether is replaced by bisphenol A diglycidyl ether. The remaining steps are the same to prepare a highly heat-resistant, degradable photocurable resin containing a spirocyclic diacetal structure, which is named P-VPAE.

[0171] Comparative Synthesis Example 1

[0172] The present comparative synthesis example 1 refers to the preparation method of the synthetic example 1, but in step (3), 1,6-naphthalene diglycidyl ether is replaced by epichlorohydrin (without a dihydroxy structure) to prepare a comparative photocurable resin sample, which is named P-VPE.

[0173] Example 1

[0174] In this embodiment 1, the following raw material components are preliminarily mixed in a blender according to weight proportions, and then kneaded using a three-roll mill to obtain a high-performance photosensitive solder resist ink:

[0175] 100 parts of a highly heat-resistant, degradable photocurable resin (P-VPNE) containing a spirocyclic diacetal structure,

[0176] Photoinitiator (2-isopropylthioxanthone) 3 parts.

[0177] Example 2

[0178] In this embodiment 2, the following raw material components are preliminarily mixed in a blender by weight, and then kneaded by a three-roll mill to obtain a high-performance photosensitive solder resist ink:

[0179] 100 parts of a highly heat-resistant, degradable photocurable resin (P-VPAE) containing a spirocyclic diacetal structure,

[0180] Photoinitiator (2-isopropylthioxanthone) 3 parts.

[0181] Comparative Example 1

[0182] In this comparative example 1, the following raw material components were preliminarily mixed in a blender by weight, and then kneaded using a three-roll mill to obtain a photosensitive solder resist ink comparison sample:

[0183] Photocurable resin comparison sample (P-VPE) 100 copies,

[0184] Photoinitiator (2-isopropylthioxanthone) 3 parts.

[0185] 3. Test results

[0186] The photosensitive solder resist inks prepared in Examples 1 to 2 and Comparative Example 1 were exposed 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 and tested as a sample according to the above "2. Test method". The performance comparison is shown in Table 1 below:

[0187] Table 1 Performance of photosensitive solder resist ink prepared in Examples 1-2 and Comparative Example 1

[0188]

[0189] It is obvious that the mechanical properties of the photosensitive solder resist ink prepared in Comparative Example 1 after curing are significantly inferior to those of Examples 1 and 2, and when the dihydroxy epoxy compound in Example 1 is selected as 1,6-naphthalene diglycidyl ether, its mechanical properties are also significantly better than those in Example 2 when the dihydroxy epoxy compound is selected as bisphenol A diglycidyl ether.

[0190] The degradation test results are shown in Table 2 below:

[0191] Table 2 Degradation properties of photosensitive solder resist inks prepared in Examples 1 to 2 and Comparative Example 1

[0192]

[0193] ○ indicates that it can be degraded by acid catalysis, and × indicates that it cannot be completely degraded by acid catalysis.

[0194] The rest of the test results are as follows Figures 1 to 10 shown.

Claims

1. A highly heat-resistant, degradable photocurable resin containing a spirocyclic diacetal structure, characterized in that The method comprises the following steps: firstly, a lignin-derived structural monomer compound containing an aldehyde group and pentaerythritol are subjected to a diacetal reaction to obtain a spiro diacetal phenol resin; then, the spiro diacetal phenol resin is subjected to a ring-opening reaction with bisphenol A diglycidyl ether or 1,6-naphthalene diglycidyl ether to obtain a spiro diacetal-modified epoxy compound; then, the obtained spiro diacetal-modified epoxy compound is modified with an acrylic modifier and then subjected to an esterification reaction with an acid anhydride to obtain the highly heat-resistant and degradable photocurable resin containing a spiro diacetal structure; The aldehyde-containing lignin-derived structural monomer compound is vanillin.

2. The photocurable resin according to claim 1, characterized in that: The aldehyde-containing lignin-derived structural monomer compound and pentaerythritol undergo a diacetal reaction to obtain a spirocyclic diacetal phenol resin. Specifically, the aldehyde-containing lignin-derived structural monomer compound and pentaerythritol are dissolved in an organic solvent A, an acetal reaction catalyst is added, and the reaction is stirred for at least 22 hours to obtain the spirocyclic diacetal phenol resin.

3. The photocurable resin according to claim 1, characterized in that: The spiro diacetal phenol resin is subjected to a ring-opening reaction with bisphenol A diglycidyl ether or 1,6-naphthalene diglycidyl ether to obtain a spiro diacetal-modified epoxy compound. Specifically, the spiro diacetal phenol resin is added to bisphenol A diglycidyl ether or 1,6-naphthalene diglycidyl ether, and a ring-opening reaction catalyst A and an antioxidant are added, and the reaction is carried out for at least 4 hours to obtain the spiro diacetal-modified epoxy compound.

4. The photocurable resin according to claim 1, characterized in that: The spirobiacetal-modified epoxy compound is modified by an acrylic modifier and then subjected to an esterification reaction with an acid anhydride. The spirobiacetal-modified epoxy compound is dissolved in an organic solvent B, an acrylic modifier is added to carry out a ring-opening reaction, and then subjected to an esterification reaction with an acid anhydride to prepare a highly heat-resistant and degradable photocurable resin containing a spirobiacetal structure.

5. The photocurable resin according to claim 1, characterized in that: The aldehyde-containing lignin-derived structural monomer compound is added in a molar ratio of (2 to 2.2):1 to pentaerythritol; the spirocyclic diacetal phenol resin is added in a molar ratio of 1:(2 to 2.2) to bisphenol A diglycidyl ether or 1,6-naphthalene diglycidyl ether; the spirocyclic diacetal-modified epoxy compound is added in a molar ratio of 1:(2 to 2.2) to the acrylic modifier, and in a molar ratio of 1:(1 to 4) to the anhydride group of the acid anhydride.

6. The photocurable resin according to claim 1, characterized in that The preparation method mainly comprises the following steps: (1) In an air atmosphere, preheating an organic solvent A to 50-60° C., adding an aldehyde-containing lignin-derived structural monomer compound and pentaerythritol to dissolve them, then heating to 85-95° C., adding an acetal reaction catalyst, maintaining the temperature at 85-95° C., stirring and reacting for 22-26 hours, and obtaining a spirobisacetal phenol resin solution; (2) pouring the spirocyclic diacetal phenol resin solution obtained in step (1) into ice water until the reaction solution is completely precipitated, and filtering to obtain a spirocyclic diacetal phenol resin solid powder; (3) in an air atmosphere, preheating bisphenol A diglycidyl ether or 1,6-naphthalene diglycidyl ether until it is in a liquid state, adding the spirocyclic diacetal phenol resin solid powder obtained in step (2), a ring-opening reaction catalyst A and an antioxidant, and then heating to 95 to 105° C. and reacting for 4 to 6 hours to obtain a spirocyclic diacetal-modified epoxy compound; (4) In an air atmosphere, preheating the organic solvent B to 75-95° C., adding the spirocyclic biacetal-modified epoxy compound obtained in step (3) and dissolving it, cooling the mixture to 55-65° C., then adding an acrylic modifier, a ring-opening reaction catalyst B and a polymerization inhibitor, and mixing the mixture. The mixture is heated to 100-110° C. and stirred for reaction for 12-16 hours. After the time is up, the temperature is adjusted to 70-90° C., the polymerization inhibitor and anhydride are added and mixed, and the temperature is adjusted to 95-105° C. and stirred for reaction for 10-12 hours to prepare a highly heat-resistant, degradable photocurable resin containing a spirocyclic biacetal structure.

7. A high-performance photosensitive solder resist ink using the high heat-resistant, degradable photocurable resin containing a spirocyclic biacetal structure as claimed in claim 1 as a main component, characterized in that The raw materials mainly include: 100 parts of a highly heat-resistant, degradable photocurable resin containing a spirocyclic diacetal structure, 1 to 5 parts of photoinitiator.

8. The high performance photosensitive solder resist ink according to claim 7, 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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