Acrylic photosensitive resin containing carbamate group, photosensitive resin composition and photosensitive solder resist ink

Abstract

The invention discloses acrylic photosensitive resin containing a carbamate group, a photosensitive resin composition and photosensitive solder resist ink, and relates to the technical field of photosensitive solder resist ink. The embodiment of the invention provides acrylic photosensitive resin containing a carbamate group. The acrylic photosensitive resin is prepared from the following raw materials: an acrylate copolymer with a side chain containing hydroxyl, an anhydride compound and an isocyanate compound, wherein the acid anhydride compound can react with part of hydroxyl on the side chain of the acrylate copolymer through an acid anhydride group to obtain acrylate grafted with the acid anhydride compound; the isocyanate compound can react with the residual part of hydroxyl on the side chain of the acrylate copolymer through the isocyanate group to obtain the acrylic photosensitive resin containing the carbamate group. When the acrylic photosensitive resin containing the carbamate group is used for photosensitive solder resist ink, the adhesion, heat resistance and flexibility of a dry film prepared from the photosensitive solder resist ink can be improved.

Description

Technical Field

[0001] The present application relates to the field of photosensitive solder resist inks, and in particular to an acrylic photosensitive resin containing a carbamate group, a photosensitive resin composition, and a photosensitive solder resist ink. Background Art

[0002] Solder mask ink plays a vital role in the manufacture of printed circuit boards (PCBs) and high-density packaging substrates. It primarily provides circuit insulation protection, preventing short circuits and leakage, while also improving the mechanical strength and electrical performance of the substrate, thereby extending its service life. As electronic products evolve toward miniaturization, lightweighting, and higher performance, solder mask inks must possess enhanced flexibility, adhesion, and resolution to accommodate the development of advanced packaging technologies such as flip chip ball grid array (FCBGA) and flip chip chip scale package (FCCSP). For packaging substrates like FCBGA and FCCSP, solder mask ink performance requirements are particularly stringent, requiring high adhesion, excellent flexibility, and heat resistance to accommodate the high-temperature processes and complex environments encountered within the packaging substrates. Furthermore, with the trend toward miniaturization and high density, solder mask inks must also possess high resolution to meet the demands of fine circuit fabrication.

[0003] Traditional epoxy acrylate photosensitive resins have disadvantages such as low resolution, poor adhesion, and high brittleness after curing, which limit their application in high-end packaging substrates. Patent CN103772639 A discloses a polyurethane acrylic resin and a preparation method thereof. By preparing a hydroxyl-terminated polyacrylate with a hydroxyl group at one end of the molecular chain and an isocyanate-terminated prepolymer with an isocyanate group at both ends of the molecular chain, and then reacting the hydroxyl-terminated polyacrylate and the isocyanate-terminated prepolymer to obtain a polyurethane acrylic ink resin. However, this polyurethane acrylic ink is mainly aimed at industries such as gravure printing, and has low requirements for resolution. Patent CN114479552A discloses a solder mask ink and its preparation method and application. However, this solder mask ink has disadvantages such as insufficient flexibility and poor adhesion. Summary of the Invention

[0004] In view of this, the present application provides an acrylic photosensitive resin containing a carbamate group, a photosensitive resin composition and a photosensitive solder mask ink, aiming to improve the existing solder mask inks having unsatisfactory adhesion, heat resistance, developing performance, flexibility or storage performance.

[0005] In a first aspect, an embodiment of the present application provides an acrylic photosensitive resin containing a carbamate group, wherein the raw materials for preparing the acrylic photosensitive resin containing a carbamate group include an acrylic ester copolymer containing hydroxyl groups on the side chain, an acid anhydride compound, and an isocyanate compound; wherein the acid anhydride compound can react with part of the hydroxyl groups on the side chain of the acrylic ester copolymer through the acid anhydride group to obtain an acrylic ester grafted with the acid anhydride compound, and the isocyanate compound can react with the remaining part of the hydroxyl groups on the side chain of the acrylic ester copolymer through the isocyanate group to obtain the acrylic photosensitive resin containing a carbamate group.

[0006] In some embodiments of the present application, the structure of the acrylic ester copolymer containing hydroxyl groups on the side chains is shown in formula (1):

[0007]

[0008] Among them, unit A is the first functional unit that provides side chain hydroxyl groups; unit B is a toughening unit; unit C is a rigid unit; unit D is the second functional unit; n, p, q are positive integers or zero, and n, p, q cannot be 0 at the same time; m is a positive integer.

[0009] In some embodiments of the present application, calculated by molar amount, the A unit: the B unit: the C unit: the D unit is (1-50): (10-50): (1-50): (1-50); preferably, the A unit: the B unit: the C unit: the D unit is (18-22): (18-22): (8-12): (8-12).

[0010] In some embodiments of the present application, calculated by molar amount, the ratio of the A unit: the acid anhydride compound: the isocyanate compound is 1: (0.1-0.9): (0.1-0.9), preferably, the A unit: the acid anhydride compound: the isocyanate compound is 1: (0.6-0.9): (0.1-0.4) further, the A unit: the acid anhydride compound: the isocyanate compound is 1: (0.6-0.8): (0.2-0.4).

[0011] In some embodiments of the present application, the monomer forming the A unit is but not limited to at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, hydroxypropyl acrylate, and hydroxypropyl methacrylate;

[0012] and / or, the monomers forming the B unit include, but are not limited to, at least one of cis-4-methyl-2-pentene, cis-3-hexene, polyethylene glycol methyl ether methacrylate, butyl methacrylate, isooctyl acrylate, hexyl methacrylate, undecyl methacrylate, 2-morpholinylethyl methacrylate, 6-methylheptyl acrylate, and 6-chlorohexyl methacrylate;

[0013] and / or, the monomers forming the C unit include, but are not limited to, at least one of styrene, α-methylstyrene, benzyl methacrylate, 2-phenoxyethyl methacrylate, styrene methacrylate, 1-ethylcyclohexyl methacrylate, and 3-phenoxybenzyl acrylate;

[0014] and / or, the monomer forming the D unit includes, but is not limited to, at least one of pentabromobenzyl methacrylate, 9-anthracenemethyl acrylate, 2-(perfluorooctyl)ethyl methacrylate, methyl methacrylate, trimethylsilyl methacrylate, 1H,1H,2H,2H-nonafluorohexyl methacrylate, 2-naphthyl acrylate, and perfluoroalkylethyl acrylate;

[0015] And / or, the acid anhydride compound includes but is not limited to one or more of tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, itaconic anhydride, maleic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, nadic anhydride, hexafluorinated phthalic anhydride, and anhydrous phthalic anhydride;

[0016] And / or, the isocyanate compound includes but is not limited to at least one of octadecyl isocyanate, octyl isocyanate, butyl isocyanate, tert-butyl isocyanate, isocyanoethyl methacrylate, 3,3′-dimethyl-4,4′-dimethyl-4,4′-biphenyl diisocyanate, phenylene diisocyanate, 4,4′-biphenyl diisocyanate, trimethylhexamethylene diisocyanate, 4,4′-methylene-bis(2,6-diethylphenyl isocyanate), and isocyanatopropyltrimethoxysilane;

[0017] And / or, the number average molecular weight of the acrylic ester copolymer containing hydroxyl groups on the side chains is 2,000-20,000.

[0018] In some embodiments of the present application, the number average molecular weight of the acrylic photosensitive resin is 2000-20000;

[0019] And / or, the weight average molecular weight of the acrylic photosensitive resin is 2000-20000;

[0020] And / or, the PDI of the acrylic photosensitive resin is ≤2;

[0021] And / or, the solid acid value of the acrylic photosensitive resin is 30 mgKOH / g-120 mgKOH / g.

[0022] A second aspect of the present application provides a photosensitive resin composition, which includes the acrylic photosensitive resin containing a carbamate group.

[0023] A third aspect of the present application provides a photosensitive solder resist ink, wherein the photosensitive solder resist ink comprises an acrylic photosensitive resin containing a carbamate group.

[0024] In some embodiments of the present application, the photosensitive solder resist ink further includes at least one of a photosensitizer, a filler, a photoinitiator, a thermosetting agent, a pigment, a leveling agent, a defoaming agent, a thermosetting component, a photocrosslinking monomer, and a third solvent.

[0025] In some embodiments of the present application, the photosensitive solder resist ink comprises, calculated by weight:

[0026] 60 to 70 parts of the acrylic photosensitive resin containing a carbamate group;

[0027] 0.01 to 0.1 parts of the photosensitizer;

[0028] 20 to 35 parts of the filler;

[0029] 1.8 to 2.8 parts of the photoinitiator;

[0030] 15.0 to 23.1 parts of the heat curing component;

[0031] 0.6 to 1.0 parts of the thermal curing agent;

[0032] 0.1 to 1.0 parts of the pigment;

[0033] 2.5 to 6.3 parts of the leveling agent;

[0034] 0.25 to 0.5 parts of the defoaming agent;

[0035] The photocrosslinking monomer is 7.5 to 15.0 parts.

[0036] Beneficial effects:

[0037] In the present application, an acrylic ester copolymer containing hydroxyl groups in the side chain, an acid anhydride compound and an isocyanate compound are used as raw materials. The acid anhydride groups in the acid anhydride compound react with the hydroxyl groups in the acrylic ester copolymer to obtain an acrylic ester intermediate product grafted with the acid anhydride compound, and then the isocyanate groups in the isocyanate compound react with the remaining hydroxyl groups in the acrylic ester intermediate product grafted with the acid anhydride compound to obtain an acrylic photosensitive resin containing a carbamate group. The acrylic photosensitive resin containing a carbamate group prepared in the embodiment of the present application has a molecular structure having a combination of a carbamate group and an acrylate group with strong hydrogen bond interactions, which is beneficial to improving the adhesion, heat resistance and flexibility of the acrylic photosensitive resin.

[0038] At the same time, after the introduction of carbamate groups into the acrylate copolymer, it is beneficial to improve its adhesion to the substrate (such as a copper substrate). When the acrylic photosensitive resin containing carbamate groups in the present application is used for photosensitive solder resist ink (also known as ink), the photosensitive solder resist ink can exhibit excellent adhesion and heat resistance (glass transition temperature is above 110°C), can maintain interlayer stability under high temperature process conditions, and improve its peeling force with the copper surface, effectively avoiding delamination and peeling, thereby ensuring the reliability of high-precision electronic packaging. In addition, the carbamate group also gives the ink excellent chemical resistance, effectively protects the substrate in acid, alkali and organic solvent environments, and extends the service life of electronic components. The prepared photosensitive solder resist ink of the acrylic photosensitive resin containing carbamate groups also has excellent storage performance, and can still maintain good adhesion and rheological properties after long-term storage, and has good storage performance, thereby reducing waste in the production process and improving the economy and convenience of manufacturing. The photosensitive solder resist ink also has good pattern resolution and can generate clear and fine patterns after exposure. It is particularly suitable for the precision manufacturing of high-density circuits, and improves the precision and reliability of packaging substrates (such as FCBGA, FCCSP, etc.). BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 This is the ATR-FTIR characterization spectrum of the product prepared in Example 1 of the acrylic photosensitive resin of the present application;

[0041] Figure 2 The photosensitive solder resist ink prepared in Example 1 of the present application is 200mJ / cm 23D confocal image after exposure;

[0042] Figure 3 1 is a graph of the tensile modulus of a dry film prepared from the photosensitive solder resist ink prepared in Ink Example 1 of the present application;

[0043] Figure 4 This is a peeling force curve of the dry film prepared by the photosensitive solder mask ink prepared in the ink experimental example of this application and the copper foil. DETAILED DESCRIPTION

[0044] The experimental examples described in this application are only some of the embodiments of this application, not all of them. All other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain this application and are not intended to limit this application.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0046] In the description of this application, the term "including" means "including but not limited to." The terms first, second, third, etc. are used merely as labels and do not impose numerical requirements or establish a sequence.

[0047] In this application, "and / or" describes the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural.

[0048] In this application, "at least one" means one or more, and "plurality" means two or more. "One or more", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or plural, respectively.

[0049] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a hard limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numbers within the range. For example, the description of a range from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which applies regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0050] Solder mask ink plays a vital role in the manufacture of printed circuit boards (PCBs) and high-density packaging substrates. It primarily provides circuit insulation protection, preventing short circuits and leakage, while also improving the mechanical strength and electrical performance of the substrate, thereby extending its service life. As electronic products evolve toward miniaturization, lightweighting, and higher performance, solder mask inks must possess enhanced flexibility, adhesion, and resolution to accommodate the development of advanced packaging technologies such as flip chip ball grid array (FCBGA) and flip chip chip scale package (FCCSP). For packaging substrates like FCBGA and FCCSP, solder mask ink performance requirements are particularly stringent, requiring high adhesion, excellent flexibility, and heat resistance to accommodate the high-temperature processes and complex environments encountered within the packaging substrates. Furthermore, with the trend toward miniaturization and high density, solder mask inks must also possess high resolution to meet the demands of fine circuit fabrication.

[0051] Traditional epoxy acrylate photosensitive resins have disadvantages such as low resolution, poor adhesion, and high brittleness after curing, which limit their application in high-end packaging substrates. Patent CN 103772639 A discloses a polyurethane acrylic resin and its preparation method. By preparing a hydroxyl-terminated polyacrylate with a hydroxyl group at one end of the molecular chain and an isocyanate-terminated prepolymer with isocyanate groups at both ends of the molecular chain, the hydroxyl-terminated polyacrylate and the isocyanate-terminated prepolymer are reacted to produce a polyurethane acrylic ink resin. However, this polyurethane acrylic ink is mainly targeted at industries such as gravure printing and has low resolution requirements. Patent CN 114479552A discloses a solder mask ink and its preparation method and application. However, this solder mask ink has disadvantages such as insufficient flexibility and poor adhesion.

[0052] Based on the above problems, the present invention provides an acrylic photosensitive resin containing a carbamate group, a photosensitive resin composition and a photosensitive solder mask ink, aiming to improve the existing solder mask inks having unsatisfactory adhesion, heat resistance, developing performance, flexibility or storage performance.

[0053] In a first aspect, the present application provides an acrylic photosensitive resin containing a carbamate group. The raw materials for preparing the acrylic photosensitive resin containing a carbamate group include an acrylic ester copolymer containing hydroxyl groups on the side chain, an acid anhydride compound, and an isocyanate compound; wherein the acid anhydride compound can react with part of the hydroxyl groups on the side chain of the acrylic ester copolymer through the acid anhydride group to obtain an acrylic ester grafted with the acid anhydride compound (that is, the product of the grafting reaction between the acid anhydride compound and the acrylic ester copolymer), and the isocyanate compound can react with the remaining part of the hydroxyl groups on the side chain of the acrylic ester copolymer (that is, the product of the grafting reaction between the acid anhydride compound and the acrylic ester copolymer) through the isocyanate group to obtain an acrylic photosensitive resin containing a carbamate group (also known as a polyurethane structure).

[0054] In the present application, an acrylic ester copolymer containing hydroxyl groups in the side chain, an acid anhydride compound and an isocyanate compound are used as raw materials. The acid anhydride groups in the acid anhydride compound react with the hydroxyl groups in the acrylic ester copolymer to obtain an acrylic ester intermediate product grafted with the acid anhydride compound, and then the isocyanate groups in the isocyanate compound react with the remaining hydroxyl groups in the acrylic ester intermediate product grafted with the acid anhydride compound to obtain an acrylic photosensitive resin containing a carbamate group. The acrylic photosensitive resin containing a carbamate group prepared in the embodiment of the present application has a molecular structure having a combination of a carbamate group and an acrylate group with strong hydrogen bond interactions, which is beneficial to improving the adhesion, heat resistance and flexibility of the acrylic photosensitive resin.

[0055] At the same time, after the introduction of carbamate groups into the acrylate copolymer, it is beneficial to improve its adhesion to the substrate (such as a copper substrate). When the acrylic photosensitive resin containing carbamate groups in the present application is used for photosensitive solder resist ink (also known as ink), the photosensitive solder resist ink can exhibit excellent adhesion and heat resistance (glass transition temperature is above 110°C), can maintain interlayer stability under high temperature process conditions, and improve its peeling force with the copper surface, effectively avoiding delamination and peeling, thereby ensuring the reliability of high-precision electronic packaging. In addition, the carbamate group also gives the ink excellent chemical resistance, effectively protects the substrate in acid, alkali and organic solvent environments, and extends the service life of electronic components. The prepared photosensitive solder resist ink of the acrylic photosensitive resin containing carbamate groups also has excellent storage performance, and can still maintain good adhesion and rheological properties after long-term storage, and has good storage performance, thereby reducing waste in the production process and improving the economy and convenience of manufacturing. The photosensitive solder resist ink also has good pattern resolution and can generate clear and fine patterns after exposure. It is particularly suitable for the precision manufacturing of high-density circuits, and improves the precision and reliability of packaging substrates (such as FCBGA, FCCSP, etc.).

[0056] In some embodiments of the present application, the mass ratio of the acrylic ester copolymer containing hydroxyl groups on the side chain: the acid anhydride compound: the isocyanate compound is (50-500): (20-100): (10-50). The acrylic ester copolymer in the present application has a side chain hydroxyl group. The side chain hydroxyl groups in the acrylic ester copolymer react with the acid anhydride to form an ester bond and a carboxyl group, and the side chain hydroxyl groups react with the isocyanate to form a carbamate group. By ensuring that the side chain hydroxyl group-containing acrylic ester copolymer, the acid anhydride compound, and the isocyanate in the preparation raw materials meet the above ratio, it is helpful to control the crosslinking density of the system and introduce an appropriate amount of carbamate groups, thereby balancing the flexibility and mechanical strength of the material.

[0057] For example, the mass fraction of the acrylate copolymer containing hydroxyl groups on the side chain is 50, 100, 150, 200, 250, 300, 350, 400, 450, 500 and the range between any two of the above values. It should be noted that the acrylate copolymer containing hydroxyl groups on the side chain is the basic material for preparing acrylic photosensitive resins containing carbamate groups, which is conducive to making the prepared acrylic photosensitive resins have excellent film-forming properties and flexibility; and the acrylate copolymer containing hydroxyl groups on the side chain can provide reactive hydroxyl groups to introduce different functional groups. When the mass of the acrylate copolymer containing hydroxyl groups on the side chain in the preparation raw material is less than 50, it is easy to cause insufficient number of reactive hydroxyl groups in the resin system, making it difficult to fully react with the anhydride compound or isocyanate compound in the raw material, resulting in too low crosslinking density of the system, poor mechanical properties after film formation, insignificant improvement in adhesion and heat resistance, and easy to cause failure problems such as film cracking or peeling. When the weight percentage of the acrylate copolymer containing hydroxyl groups in the raw materials exceeds 500, the relatively high content of the acrylate copolymer containing hydroxyl groups in the side chains can dilute the proportion of crosslinking components (such as thermosetting components and photocrosslinking monomers), resulting in incomplete system reaction and reduced crosslinking efficiency, which in turn affects the chemical resistance, heat resistance, and dimensional stability of the film. Furthermore, excessive content of the acrylate copolymer containing hydroxyl groups in the side chains can also lead to excessive system viscosity, affecting workability and photolithographic development results.

[0058] Exemplarily, the mass fraction of the anhydride compound is 20, 30, 40, 50, 60, 70, 80, 90, 100 and the range value between any two of the above values. It should be noted that the anhydride compound, as one of the cross-linking agents, can react with the hydroxyl group in the copolymer to form an ester bond, thereby improving the heat resistance and mechanical strength of the film layer. When the mass fraction of the anhydride compound is less than 20, the prepared acrylic photosensitive resin has less carboxyl content. Because it is an alkali-soluble resin, the developing time will be longer, which can easily lead to problems such as unclean developing. When the mass fraction of the anhydride compound is higher than 100, the prepared acrylic photosensitive resin has too many carboxylic acid or ester groups, is too hydrophilic, easily absorbs water and ages, and reduces storage stability and electrical insulation performance. At the same time, the carboxyl content is too high, resulting in a shorter developing time, which can easily lead to the phenomenon of over-development.

[0059] For example, the mass fraction of the isocyanate compound is 10, 15, 20, 25, 30, 35, 40, 45, 50, and any range between any two of the above values. The isocyanate compound acts as an auxiliary crosslinking agent and can further react with the hydroxyl group to form a polyurethane structure, which helps to increase the crosslinking network density and enhance the mechanical properties, chemical resistance, and flexibility of the film. When the mass fraction of the isocyanate compound is less than 10, the polyurethane content is likely to be too low, resulting in too few introduced carbamate groups and little improvement in adhesion properties. When the mass fraction of the isocyanate compound is greater than 50, the carbamate groups are excessive, which can easily lead to gelation in the reaction.

[0060] In some embodiments of the present application, the number average molecular weight (Mn) of the acrylic photosensitive resin containing a carbamate group is 2000-20000 or the weight average molecular weight (Mw) is 2000-20000, and / or PDI ≤ 2, and / or the solid acid value is 30 mgKOH / g-120 mgKOH / g.

[0061] It should be noted that when Mn or Mw is less than 2000, the chain segments of the acrylic photosensitive resin containing carbamate groups are too short, and the crosslinking network is sparse, which can easily lead to insufficient cured film strength, insufficient peel force, and easy pattern deformation. When Mn is higher than 20,000 or Mw is higher than 20,000, it is easy to make the acrylic photosensitive resin containing carbamate groups difficult to dissolve, increasing development time. At the same time, the viscosity of the system is significantly increased, making coating and grinding difficult. The prepared photosensitive solder mask ink has poor fluidity and reduced wettability with the substrate.

[0062] The PDI (polymer dispersity index) of the carbamate-containing acrylic photosensitive resin prepared in this application is ≤ 2. This allows the prepared carbamate-containing acrylic photosensitive resin to have a narrow molecular weight distribution, resulting in a highly controlled polymerization system. The prepared acrylic photosensitive resin exhibits good developability, uniformity, and repeatability in inks. If the PDI is greater than 2, the prepared acrylic photosensitive resin system contains a large amount of a mixture of short and long chains. However, short chains are difficult to crosslink and cure, which can easily lead to low mechanical strength of the cured film of the prepared acrylic photosensitive resin system. Excessive long chains can easily lead to poor fluidity, residual development, and blurred patterns in the acrylic photosensitive resin system.

[0063] When the acid value is below 30 mgKOH / g, the prepared acrylic photosensitive resin contains a low carboxyl group content. Because it is an alkali-soluble resin, the development time is long, which can easily lead to problems such as unclean development. When the acid value is above 120 mgKOH / g, the prepared acrylic photosensitive resin contains too many carboxylic acid or ester groups, making it too hydrophilic and prone to water absorption and aging, which reduces storage stability and electrical insulation properties. At the same time, too high a carboxyl group content results in a short development time, which can easily lead to overdevelopment.

[0064] In some embodiments of the present application, the structure of the acrylic ester copolymer containing hydroxyl groups on the side chains is shown in formula (1):

[0065]

[0066] Among them, unit A is the first functional unit that provides side chain hydroxyl groups; unit B is a toughening unit; unit C is a rigid unit; unit D is the second functional unit; n, p, q are positive integers or zero, and n, p, q cannot be 0 at the same time; m is a positive integer.

[0067] Exemplarily, m, n, p, and q are all non-zero, that is, m, n, p, and q are all positive integers, and the monomers forming unit A, unit B, unit C, and unit D are all unsaturated compounds containing double bonds or triple bonds, which can undergo copolymerization or homopolymerization under the action of an initiator.

[0068] It is understood that the A unit provides reactive hydroxyl groups that can react with crosslinking agents such as isocyanates, thereby enhancing the functionalization of the acrylate copolymer containing hydroxyl groups in the chain. In some embodiments of the present application, the monomer forming the A unit is an unsaturated monomer containing a double bond, which can form a corresponding acrylate copolymer containing hydroxyl groups in the side chain through copolymerization or homopolymerization under the action of an initiator. Exemplarily, the monomer forming the A unit includes, but is not limited to, at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, and hydroxypropyl acrylate, and hydroxypropyl methacrylate.

[0069] It is understood that the B unit is a toughening unit, which is beneficial to improving the toughness and flexibility of the material having the structural unit. In some embodiments of the present application, the monomer forming the B unit is an unsaturated monomer containing a double bond, which can form a corresponding side chain hydroxyl-containing acrylate copolymer by copolymerization or homopolymerization under the action of an initiator. Exemplarily, the monomer forming the B unit includes but is not limited to at least one of cis-4-methyl-2-pentene, cis-3-hexene, polyethylene glycol methyl ether methacrylate, butyl methacrylate, isooctyl acrylate, hexyl methacrylate, undecyl methacrylate, 2-morpholinoethyl methacrylate, 6-methylheptyl acrylate and 6-chlorohexyl methacrylate.

[0070] It is understandable that the C unit is a rigid unit. For example, the C unit serves to provide a rigid structure such as a benzene ring structure to improve the rigidity, dimensional stability and heat resistance of the material having the structural unit. In some embodiments of the present application, the monomer forming the C unit is an unsaturated monomer containing a double bond, which can form a corresponding side chain hydroxyl-containing acrylate copolymer through copolymerization or homopolymerization under the action of an initiator. Exemplarily, the monomer forming the C unit includes but is not limited to at least one of styrene, α-methylstyrene, benzyl methacrylate, 2-phenoxyethyl methacrylate, styrene methacrylate, 1-ethylcyclohexyl methacrylate and 3-phenoxybenzyl acrylate.

[0071] It is understood that the D unit is a second functional unit, for example, the D unit can be selectively introduced to give the material special properties (such as low dielectric, low water absorption, thermal stability, etc.). In some embodiments of the present application, the monomer forming the D unit is an unsaturated monomer containing a double bond, which can be formed by copolymerization or homopolymerization under the action of an initiator to form a corresponding side chain hydroxyl-containing acrylate copolymer. Exemplarily, the monomer forming the D unit includes but is not limited to pentabromobenzyl methacrylate, 9-anthracene methyl acrylate, 2-(perfluorooctyl)ethyl methacrylate, methyl methacrylate, trimethylsilyl methacrylate, 1H,1H,2H,2H-nonafluorohexyl methacrylate, 2-naphthyl acrylate and at least one of perfluoroalkylethyl acrylate.

[0072] Furthermore, calculated by molar amount, the ratio of the A unit: the B unit: the C unit: the D unit is (1-50): (10-50): (1-50): (1-50); further, the A unit: the B unit: the C unit: the D unit is (18-22): (18-22): (8-12): (8-12). In this embodiment, by selecting different functional monomers and optimizing the ratio of different monomers, compared with epoxy resin, it is possible to achieve a synergistic effect of flexibility and rigidity, so that the pattern structure formed after exposure can avoid brittle cracking and is not easily deformed, which is conducive to maintaining the pattern size accuracy.

[0073] In some embodiments of the present application, the molar ratio of the A unit: the anhydride compound: the isocyanate compound is 1:(0.1-0.9):(0.1-0.9). The acrylate copolymer in the present application has side chain hydroxyl groups. The side chain hydroxyl groups in the acrylate copolymer react with the anhydride to form ester bonds and carboxyl groups, and the side chain hydroxyl groups react with the isocyanate to form carbamate groups. By ensuring that the side chain hydroxyl-containing acrylate copolymer, the anhydride compound, and the isocyanate in the preparation raw materials meet the above ratio, it is helpful to control the crosslinking density of the system and introduce an appropriate amount of carbamate groups, thereby balancing the flexibility and mechanical strength of the material.

[0074] For example, taking the molar amount of unit A as 1M, the molar amount of the acid anhydride compound is 0.1M, 0.2M, 0.3M, 0.4M, 0.5M, 0.6M, 0.7M, 0.8M, 0.9M and the range between any two of the above values. Correspondingly, the molar amount of the isocyanate compound is 0.1M, 0.2M, 0.3M, 0.4M, 0.5M, 0.6M, 0.7M, 0.8M, 0.9M and the range between any two of the above values. Preferably, the ratio of the unit A: the acid anhydride compound: the isocyanate compound is 1: (0.6-0.9): (0.1-0.4), and further, the ratio of the unit A: the acid anhydride compound: the isocyanate compound is 1: (0.6-0.8): (0.2-0.4). In this way, the prepared photosensitive solder resist ink can have better high stability, better adhesion and flexibility.

[0075] In some embodiments of the present application, the method for preparing a side chain hydroxyl-containing acrylic ester copolymer as shown in formula (1) includes adding an appropriate amount of a first solvent, a monomer for forming unit A, a monomer for forming unit B, a monomer for forming unit C, a monomer for forming unit D, and an initiator into a reaction vessel, so that the monomer for forming unit A, the monomer for forming unit B, the monomer for forming unit C, and the monomer for forming unit D undergo a polymerization reaction to obtain a side chain hydroxyl-containing acrylic ester copolymer as shown in formula (1). It should be noted that the monomer for forming unit A, the monomer for forming unit B, the monomer for forming unit C, and the monomer for forming unit D have been specifically described above and will not be repeated here.

[0076] For example, 100-300 parts by weight of solvent are added to a 1L reactor equipped with a thermometer, an agitator, a reflux condenser and a nitrogen-protected dropping funnel, and the temperature is raised to 80°C. Then, 50-500 parts by weight of the pre-dissolved reaction monomer (that is, the total weight of the monomer forming unit A, the monomer forming unit B, the monomer forming unit C and the monomer forming unit D), 1-10 parts by weight of the initiator and 100-300 parts by weight of the solvent mixed solution are added dropwise. The addition time is 2-4 hours. After the addition is completed, the mixture is reacted at 80°C for 4-8 hours to obtain an acrylate copolymer containing hydroxyl groups on the side chain.

[0077] In some embodiments of the present application, the solvent includes but is not limited to ethyl acetate, butyl acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol monobutyl ether acetate, toluene, tetramethylbenzene, N,N-dimethylacetamide (DMAc), methyl pyrrolidone (NMP). Preferably, one or more of ethyl acetate, butyl acetate, diethylene glycol monoethyl ether acetate and toluene are used.

[0078] Furthermore, the first initiator added in the step of preparing the acrylic ester copolymer containing hydroxyl groups on the side chains is a free radical initiator. Exemplarily, the first initiator includes an azo group, including at least one of azobisisobutyronitrile, azobisethylbutyronitrile, azobisisovaleronitrile, azobiscyclohexylcarbonitrile, dimethyl azobisisobutyrate, azoisobutylcyanamide, azobisisooctanonitrile, and tert-butyl azodiacetate.

[0079] In some embodiments of the present application, the anhydride compounds include but are not limited to one or more of tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, itaconic anhydride, maleic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, nadic anhydride, hexafluorinated phthalic anhydride, and anhydrous phthalic anhydride.

[0080] In some embodiments of the present application, the isocyanate compound may be a polyisocyanate or a monoisocyanate. Exemplarily, the isocyanate compound includes, but is not limited to, at least one of octadecyl isocyanate, octyl isocyanate, butyl isocyanate, tert-butyl isocyanate, isocyanoethyl methacrylate, 3,3′-dimethyl-4,4′-dimethyl-4,4′-biphenyl diisocyanate, phenylene diisocyanate, 4,4′-biphenyl diisocyanate, trimethylhexamethylene diisocyanate, 4,4′-methylene-bis(2,6-diethylphenyl isocyanate), and isocyanatopropyltrimethoxysilane.

[0081] In some embodiments of the present application, the acrylate copolymer containing hydroxyl groups on the side chains is a multi-component copolymer, and the number average molecular weight of the acrylate copolymer containing hydroxyl groups on the side chains is 2000-20000, or the weight average molecular weight of the acrylate copolymer containing hydroxyl groups on the side chains is 2000-20000.

[0082] In some embodiments of the present application, a first catalyst is added during the step of reacting the anhydride compound with the acrylic ester copolymer containing hydroxyl groups on the side chains. The first catalyst includes, but is not limited to, an organotin catalyst. Exemplarily, the organotin catalyst includes, but is not limited to, at least one of stannous octoate, dibutyltin dilaurate, or triphenyltin chloride.

[0083] The second aspect of the present application also provides a photosensitive resin composition, which includes the aforementioned acrylic photosensitive resin containing a carbamate group. Furthermore, the photosensitive resin composition also includes a photopolymerizable monomer, a second initiator, an additive, and a second solvent. It should be noted that the photopolymerizable monomer, the second initiator, the additive, and the second solvent in the photosensitive resin composition do not belong to the main improvements in the present application and are not described in detail here. The photosensitive resin composition in the present application includes the aforementioned acrylic photosensitive resin containing a carbamate group, which also has the beneficial effects of an acrylic photosensitive resin containing a carbamate group.

[0084] The third aspect of the present application further provides a photosensitive solder resist ink, which includes the aforementioned acrylic photosensitive resin containing a carbamate group.

[0085] In some embodiments of the present application, the photosensitive solder resist ink further includes at least one of a photosensitizer, a filler, a photoinitiator, a thermal curing agent, a pigment, a leveling agent, a defoaming agent, a thermal curing component, a photocrosslinking monomer, and a third solvent.

[0086] Furthermore, the mass fraction of the acrylic photosensitive resin containing carbamate groups in the photosensitive solder resist ink is 60 to 70 parts by mass. It should be noted that when the mass fraction of the photosensitive resin (i.e., the acrylic photosensitive resin containing carbamate groups) in the photosensitive solder resist ink is less than 60 parts by mass, the proportion of other components in the photosensitive solder resist ink (e.g., inorganic fillers, photocrosslinking monomers, etc.) is relatively high, which can easily lead to brittleness and poor adhesion of the prepared cured film. When the mass fraction of the photosensitive resin in the photosensitive solder resist ink is greater than 70 parts by mass, the viscosity of the photosensitive solder resist ink is likely to increase significantly, which is not conducive to coating and printing. In addition, the proportion of other components in the photosensitive solder resist ink (e.g., inorganic fillers, photocrosslinking monomers, etc.) is relatively low, which can easily lead to insufficient hardness of the cured film layer and poor thermal stability of the solder resist dry film.

[0087] Furthermore, the mass fraction of the photosensitizer in the photosensitive solder resist ink is 0.01-0.1 parts by weight, preferably 0.02-0.08 parts by weight, and more preferably 0.04-0.06 parts by weight. The specific material of the photosensitizer is not a major improvement of the present application and is not limited here.

[0088] Furthermore, the filler in the photosensitive solder resist ink has a mass fraction of 20-35 parts by weight. Furthermore, the filler is an inorganic filler. The inorganic filler may be an inorganic filler modified to have reactive functional groups on its surface, or an inorganic filler that has not been surface-modified. The inorganic filler includes at least one of barium sulfate, barium titanate, calcium oxide, talc, fumed silica, silica, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, titanium oxide, mica powder, and kaolin. Preferably, the inorganic filler is selected from at least one of barium sulfate, silica, aluminum oxide, aluminum hydroxide, and calcium carbonate. Illustratively, the inorganic filler includes a silica filler and a barium sulfate filler, the mass fraction of the silica filler in the photosensitive solder resist ink is 5.5-8.3 parts by weight, preferably 6.0-7.5 parts by weight, and more preferably 6.5-7.0 parts by weight; the mass fraction of the barium sulfate filler in the photosensitive solder resist ink is 18.5-23.0 parts by weight, preferably 19.0-21.0 parts by weight, and more preferably 20.0-21.0 parts by weight.

[0089] For example, the particle size of the inorganic filler ranges from 0.001 μm to 100 μm, preferably from 0.05 μm to 20 μm, and more preferably from 0.05 μm to 3 μm. In particular, when the photosensitive resin composition requires further grinding, the particle size of the inorganic filler can be adjusted to other ranges, and the specific value is not strictly limited.

[0090] Furthermore, the mass fraction of the photoinitiator in the photosensitive solder resist ink is 1.8-2.8 parts by weight, preferably 2.0-2.5 parts by weight, and more preferably 2.2-2.5 parts by weight. Exemplarily, the photoinitiator includes the following categories: oxime ester photoinitiators (such as OXE-1, OXE-2); acyl phosphine oxide type initiators, such as diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide and other acyl phosphine oxide compounds; acetophenone initiators (such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone); benzoin and its alkyl ether derivatives (such as benzoin, benzoin methyl ether); anthraquinone photoinitiators (such as 2-methylanthraquinone, 2-ethylanthraquinone); thioxanthones (such as 2,4-dimethylthioxanthone, 2-chlorothioxanthone); ketal initiators, such as acetophenone dimethyl ketal; dibenzophenone and its derivatives (such as benzophenone, 4,4'-bisdiethylaminobenzophenone), and other free radical generating initiators such as benzoin-acrylate complexes. These photoinitiators can be used alone or in combination, and oxime ester type or acylphosphine oxide type initiators are preferably used.

[0091] Furthermore, the thermal curing component is present in the photosensitive solder resist ink in an amount of 15.0-23.1 parts by weight, preferably 17.0-20.0 parts by weight, and more preferably 18.0-19.5 parts by weight. For example, the thermal curing component is an epoxy resin, the types of which include but are not limited to the following types: bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, hydrogenated bisphenol A epoxy resin, brominated bisphenol A epoxy resin, bixylenol epoxy resin, biphenol epoxy resin, alicyclic epoxy resin, soluble novolac epoxy resin, cresol-type epoxy resin, trisphenol methane epoxy resin, N-glycidyl epoxy resin, triglycidyl isocyanurate, 2,6-xylenol dimer diglycidyl ether, and other alicyclic epoxy resins and xylene epoxy resins.

[0092] Furthermore, the mass fraction of the thermal curing agent in the photosensitive solder resist ink is 0.6-1.0 parts by weight, preferably 0.8-0.9 parts by weight, and more preferably 0.80-0.85 parts by weight. There are no specific restrictions on the type of thermal curing agent. For example, when the thermal curing component is epoxy resin, there are no specific restrictions on the type of thermal curing agent or thermal curing accelerator used for the epoxy resin. Thermal curing agents include imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole; amine compounds such as dicyandiamide, cyanamide, and benzyldimethylamine; hydrazine compounds such as adipic acid dihydrazide; phosphine compounds such as triphenylphosphine; and s-triazine derivatives such as 2,4-diamino-6-methacryloyloxyethyl-s-triazine. In addition, specific commercial products such as isocyanate compounds 2MZ-A and 2MZ-OK, or U-CAT series products, can also be used.

[0093] Furthermore, the mass fraction of the pigment in the photosensitive solder resist ink is 0.1-1 parts by weight. Furthermore, the pigment can be selected from phthalocyanine green, phthalocyanine blue, titanium dioxide, carbon black, iron oxide red, iron oxide yellow, ultramarine, chrome yellow, chrome green, cadmium red or cadmium yellow. These pigments can be used alone or mixed as needed to achieve the desired color effect, preferably pigments that do not contain free halogen. Exemplarily, the pigment includes a blue pigment (such as phthalocyanine blue) and a green pigment (such as phthalocyanine green), and the mass fraction of the blue pigment in the photosensitive solder resist ink is 0.25-0.38 parts by weight, preferably 0.3-0.38 parts by weight, and more preferably 0.35 parts by weight; the mass fraction of the green pigment in the photosensitive solder resist ink is 0.38-0.63 parts by weight, preferably 0.5-0.63 parts by weight, and more preferably 0.55 parts by weight.

[0094] Furthermore, the mass fraction of the leveling agent in the photosensitive solder resist ink is 2.5-6.3 parts by weight, preferably 3.0-5.0 parts by weight, and more preferably 3.5-4.5 parts by weight. For example, the leveling agent can be a silicone, non-silicone (such as acrylic), polyurethane, or fluoride leveling agent, and these leveling agents can be used alone or in combination.

[0095] Furthermore, the defoamer content in the photosensitive solder resist ink is 0.25-0.5 parts by weight, preferably 0.3-0.4 parts by weight, and more preferably 0.35-0.4 parts by weight. For example, the defoamer can be silicone, polyether, mineral oil, fluoride, etc., and can be used alone or in combination to achieve the best defoaming effect. In the technical solution of the present invention, the type of defoamer is not particularly limited, but silicone or acrylate, or a mixture of the two, is preferred.

[0096] Furthermore, the mass fraction of the photocrosslinking monomer in the photosensitive solder resist ink is 7.5-15.0 parts by weight, preferably 9.0-12.0 parts by weight, and more preferably 10.0-11.5 parts by weight. The specific material of the photocrosslinking monomer is not a major improvement of this application and is not limited here.

[0097] Furthermore, the mass fraction of the third solvent in the photosensitive solder resist ink is 6.3-18.8 parts by weight, preferably 7.0-13.0 parts by weight, and more preferably 8.0-13.0 parts by weight. The specific material of the third solvent is not a major improvement of this application and is not limited here.

[0098] Furthermore, the photosensitive solder resist ink comprises, by weight, 65 parts of the aforementioned acrylic photosensitive resin containing a carbamate group, 0.01-0.1 parts of a photosensitizer, 24-32 parts of a filler, 1.8-2.8 parts of a photoinitiator, 0.6-1.0 parts of a thermal curing agent, 0.6-1 parts of a pigment, 2.5-6.3 parts of a leveling agent, 0.25-0.5 parts of a defoaming agent, 15-23.1 parts of a thermal curing component, 7.5-15 parts of a photocrosslinking monomer, and 6.3-18.8 parts of a third solvent. By optimizing the components and ratios of the photosensitive solder resist ink in this embodiment, the hardness, rheological properties, and pattern resolution of the photosensitive solder resist ink of this application are improved.

[0099] Specifically, the carbamate-containing photosensitive resin in the photosensitive solder resist ink provides the backbone and film-forming foundation; fillers (such as barium sulfate and silica) significantly influence rheological properties and pattern retention; and photocrosslinking monomers and thermosetting components jointly regulate cure density, thereby affecting hardness and dimensional stability. Photoinitiators and photosensitizers influence imaging sensitivity and exposure window control. Therefore, this embodiment optimizes the components and content ratios of the photosensitive solder resist ink to achieve synergistic effects on the performance of the photosensitive solder resist ink, thereby improving the hardness, rheological properties, and pattern resolution of the photosensitive solder resist ink.

[0100] The fourth aspect of the present application also provides a method for preparing a photosensitive solder resist ink, comprising mixing components such as an acrylic photosensitive resin containing a carbamate group, an inorganic filler, a photoinitiator, etc. according to a preset ratio, and then grinding them using a three-roll mill to ensure the uniform dispersion of the components, thereby obtaining a photosensitive solder resist ink with excellent rheological properties. It can be understood that by precisely controlling the grinding process, the rheological properties and printability of the ink can be optimized to ensure its reliability and consistency in practical applications. For example, the fineness of the photosensitive solder resist ink after mixing and grinding is reduced to less than 10um. The specific process of mixing and grinding does not belong to the main improvement points of the present application and is not limited here.

[0101] Acrylic photosensitive resin Example 1

[0102] Preparation of acrylic photosensitive resin 1 containing carbamate groups (referred to as resin 1)

[0103] 300 g of diethylene glycol monoethyl ether acetate was added to a 1 L reactor equipped with a thermometer, stirrer, reflux condenser, and nitrogen-protected dropping funnel. The temperature was raised to 80°C, and a mixed solution of pre-dissolved methyl methacrylate, hydroxyethyl methacrylate, styrene ester, butyl methacrylate, azobisisobutyronitrile, and diethylene glycol monoethyl ether acetate was then added dropwise. The molar ratio of methyl methacrylate: hydroxyethyl methacrylate: styrene ester: butyl methacrylate: azobisisobutyronitrile was 10:20:10:20:3. The mixed solution was added dropwise over 2-4 hours. After completion of the addition, the mixture was reacted at 80°C for 4-8 hours to obtain a hydroxyl-terminated acrylate copolymer. Then, the temperature was raised to 110°C, cis-4-cyclohexene-1,2-dicarboxylic anhydride (the molar ratio of cis-4-cyclohexene-1,2-dicarboxylic anhydride to hydroxyethyl methacrylate was 0.9:1), and then 2g of triphenylphosphine was added as a catalyst, and the reaction was carried out at 110°C for 8-12 hours. Then, the temperature was lowered to 60°C, and dissolved isocyanoethyl methacrylate (the molar ratio of isocyanoethyl methacrylate to hydroxyethyl methacrylate was 0.1:1), 0.5g of dibutyltin dilaurate and 30g of diethylene glycol monoethyl ether acetate mixed solution were added dropwise. The addition time was controlled within 1-2 hours. After the addition was completed, the reaction was continued at 60°C for 6-10 hours to obtain an acrylic photosensitive resin 1 containing a carbamate group, and the ATR-FTIR characterization spectrum was as follows: Figure 1 shown.

[0104] Figure 1 Characteristic absorption peaks are clearly observed at 3200 cm⁻¹, 2952.3 cm⁻¹, 1731.3 cm⁻¹, 1632.5 cm⁻¹, and 1152.6 cm⁻¹. The peak at 3200 cm⁻¹ corresponds to the stretching vibration of NH⁻¹, the peak at 2952.5 cm⁻¹ corresponds to the stretching vibration of methyl and methylene groups, the peak at 1720 cm⁻¹ corresponds to the stretching vibration of C=O, the peak at 1600 cm⁻¹ is attributed to the stretching vibration of the C=C double bond, and the peak at 1152.6 cm⁻¹ is attributed to the stretching vibration of CO. This further confirms the successful synthesis of acrylic photosensitive resin 1 containing carbamate groups. The resin has a solid acid value of 56 mgKOH / g, a number average molecular weight of 11,500, and a weight average molecular weight of 17,000.

[0105] Acrylic photosensitive resin embodiment 2 (abbreviated as resin 2)

[0106] Preparation of acrylic photosensitive resin containing carbamate groups 2

[0107] 300 g of diethylene glycol monoethyl ether acetate was added to a 1 L reactor equipped with a thermometer, stirrer, reflux condenser, and nitrogen-protected dropping funnel. The temperature was raised to 80°C, and a pre-dissolved mixed solution of methyl methacrylate, 5-hydroxypentyl acrylate, styrene methacrylate, hexyl acrylate, azobisisoheptyronitrile, and diethylene glycol monoethyl ether acetate was then added dropwise. The molar ratio of methyl methacrylate: 5-hydroxypentyl acrylate: styrene methacrylate: hexyl acrylate: azobisisobutyronitrile was 10:20:10:20:3. The mixed solution was added dropwise over 2-4 hours, and the reaction was continued at 80°C for 4-8 hours after the addition was complete. The temperature was then raised to 110°C, and cis-4-cyclohexene-1,2-dicarboxylic anhydride (the molar ratio of cis-4-cyclohexene-1,2-dicarboxylic anhydride to 5-hydroxypentyl acrylate was 0.8:1) was added. Then, 2g of triphenylphosphine was added as a catalyst and the mixture was reacted at 110°C for 8-12 hours. The temperature was then lowered to 60°C, and a mixed solution of dissolved isocyanoethyl methacrylate (the molar ratio of isocyanoethyl methacrylate to 5-hydroxypentyl acrylate was 0.2:1), 0.5g of dibutyltin dilaurate, and 30g of diethylene glycol monoethyl ether acetate was added dropwise over 1-2 hours. After the addition was complete, the reaction was continued at 60°C for 6-10 hours to obtain acrylic photosensitive resin 2 containing carbamate groups. This resin had a solid acid value of 66mgKOH / g, a number average molecular weight of 11,300, and a weight average molecular weight of 16,500.

[0108] Acrylic photosensitive resin embodiment 3 (abbreviated as resin 3)

[0109] Preparation of acrylic photosensitive resin containing carbamate groups 3

[0110] 300 g of diethylene glycol monoethyl ether acetate was added to a 1 L reactor equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen-protected dropping funnel. The temperature was raised to 80°C, and a pre-dissolved mixed solution of methyl methacrylate, 3-hydroxypropyl acrylate, styrene methacrylate, butyl methacrylate, dimethyl azobisisobutyrate, and diethylene glycol monoethyl ether acetate was then added dropwise. The molar ratio of methyl methacrylate: 3-hydroxypropyl acrylate: styrene methacrylate: butyl methacrylate: dimethyl azobisisobutyrate was 10:20:10:20:3. The mixed solution was added dropwise over 2-4 hours, and the reaction was continued at 80°C for 4-8 hours after the addition was complete. The temperature was then raised to 110°C, and cis-4-cyclohexene-1,2-dicarboxylic anhydride (the molar ratio of cis-4-cyclohexene-1,2-dicarboxylic anhydride to 3-hydroxypropyl acrylate was 0.7:1) was added. Then, 2g of triphenylphosphine was added as a catalyst, and the reaction was allowed to proceed at 110°C for 8-12 hours. The temperature was then lowered to 60°C, and a mixed solution of dissolved isocyanoethyl methacrylate (the molar ratio of isocyanoethyl methacrylate to 3-hydroxypropyl acrylate was 0.3:1), 0.5g of dibutyltin dilaurate, and 30g of diethylene glycol monoethyl ether acetate was added dropwise over 1-2 hours. After the addition was complete, the reaction was continued at 60°C for 6-10 hours to obtain acrylic photosensitive resin 3 containing carbamate groups. This resin had a solid acid value of 75mgKOH / g, a number average molecular weight of 10,800, and a weight average molecular weight of 17,500.

[0111] Acrylic Photosensitive Resin Example 4 (Referred to as Resin 4)

[0112] Preparation of acrylic photosensitive resin containing carbamate groups 4

[0113] In a 1L reactor equipped with a thermometer, stirrer, reflux condenser, and nitrogen-protected dropping funnel, 300g of diethylene glycol monoethyl ether acetate was added. The temperature was raised to 80°C, and a pre-dissolved mixed solution of methyl methacrylate, 3-hydroxypropyl acrylate, styrene, butyl methacrylate, azobisisobutyronitrile, and diethylene glycol monoethyl ether acetate was then added dropwise. The molar ratio of methyl methacrylate: 3-hydroxypropyl acrylate: styrene: butyl methacrylate: azobisisobutyronitrile was 10:20:10:20:3. The mixed solution was added dropwise over 2-4 hours, and the reaction was continued at 80°C for 4-8 hours after the addition was complete. The temperature was then raised to 110°C, and cis-4-cyclohexene-1,2-dicarboxylic anhydride (the molar ratio of cis-4-cyclohexene-1,2-dicarboxylic anhydride to 3-hydroxypropyl acrylate was 0.6:1) was added. Then, 2g of triphenylphosphine was added as a catalyst, and the reaction was allowed to proceed at 110°C for 8-12 hours. The temperature was then lowered to 60°C, and a mixed solution of dissolved isocyanoethyl methacrylate (the molar ratio of isocyanoethyl methacrylate to 3-hydroxypropyl acrylate was 0.4:1), 0.5g of dibutyltin dilaurate, and 30g of diethylene glycol monoethyl ether acetate was added dropwise over 1-2 hours. After the addition was complete, the reaction was continued at 60°C for 6-10 hours to obtain acrylic photosensitive resin 4 containing carbamate groups. This resin had a solid acid value of 82mgKOH / g, a number average molecular weight of 11,600, and a weight average molecular weight of 17,800.

[0114] Acrylic photosensitive resin comparative example 1 (referred to as resin 5)

[0115] Preparation of acrylic photosensitive resin without urethane group 5

[0116] 300 g of diethylene glycol monoethyl ether acetate was added to a 1 L reactor equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen-protected dropping funnel. The temperature was raised to 80°C, and a pre-dissolved mixed solution of methyl methacrylate, 3-hydroxypropyl acrylate, styrene methacrylate, butyl methacrylate, dimethyl azobisisobutyrate, and diethylene glycol monoethyl ether acetate was then added dropwise. The molar ratio of methyl methacrylate: 3-hydroxypropyl acrylate: styrene methacrylate: butyl methacrylate: dimethyl azobisisobutyrate was 10:20:10:20:3. The mixed solution was added dropwise over 2-4 hours, and the reaction was continued at 80°C for 4-8 hours after the addition was complete. The temperature was then raised to 110°C, and cis-4-cyclohexene-1,2-dicarboxylic anhydride (the molar ratio of cis-4-cyclohexene-1,2-dicarboxylic anhydride to 3-hydroxypropyl acrylate was 1:1) was added. Then, 2g of triphenylphosphine was added as a catalyst. The mixture was reacted at 110°C for 8-12 hours to obtain an acrylic photosensitive resin 5 that did not contain a carbamate group. This resin had a solid acid value of 94mgKOH / g, a number average molecular weight of 13100, and a weight average molecular weight of 17900.

[0117] Photosensitive solder resist ink experimental example

[0118] A photosensitive resin composition was prepared according to the components and weight fractions shown in Table 1. After stirring and mixing on a three-roll mill, the composition was reduced to a fineness of less than 10 μm to prepare a solder mask ink. Next, the solder mask ink was applied to a substrate, maintaining a coating thickness of approximately 25 μm, and soft-baked at 80°C for 10 minutes. Subsequently, the ink was exposed, developed using a 1% sodium carbonate solution, and finally heat-cured at 170°C for 1 hour. The relevant properties were tested, and the results are shown in Table 2.

[0119] In order to observe the resolution of the photosensitive solder resist ink having the acrylic photosensitive resin containing urethane groups in this application, the opening performance of the photosensitive solder resist ink in Ink Example 1 was observed using a 3D confocal microscope. The results are as follows: Figure 2 As shown, the photosensitive solder resist ink prepared in Ink Example 1 exhibits a relatively high resolution, and can open holes normally at 60 microns without overexposure.

[0120] In order to observe the mechanical properties of the photosensitive solder resist ink having the acrylic photosensitive resin containing urethane groups in this application, the photosensitive solder resist ink in Ink Example 1 was subjected to a DMA temperature rise test. Figure 3 The modulus of ink Example 1 at room temperature reaches 4.7 GPa, which has good mechanical properties.

[0121] In order to observe the adhesion between the photosensitive solder resist ink having the acrylic photosensitive resin containing urethane groups in this application and the copper foil, the photosensitive solder resist inks prepared in Ink Examples 1 to 4 were subjected to a 180° peeling test. Figure 4 As shown in the figure, the width of the prepared test strip is about 10 mm, the peeling force reaches 5 N, and the peeling strength is about 5 N / mm.

[0122] Table 1

[0123]

[0124]

[0125]

[0126] Performance Characterization

[0127] This section details the performance testing methods and results analysis for the polyurethane acrylate ink resin prepared in this invention. These tests cover key performance indicators such as developing performance, thermal properties, pencil hardness, pattern resolution, mechanical properties, and copper peel strength. Each test was conducted in accordance with international or industry standards to ensure data accuracy and reliability. Some test procedures are described below.

[0128] (1) Development performance test

[0129] The ink was spin-coated on the fixed copper substrate to form a coating film with a thickness of about 25 μm. The wafer was baked on a heating table at 80°C for 20 minutes, and then photolithography was performed using a photolithography machine with an exposure energy of 60 mJ / cm 2 ~250mJ / cm 2 Finally, the coating was developed with a 1wt% aqueous solution of Na2CO3, and the time required for complete development was recorded. Development within 30 seconds was considered "excellent," development within 30-60 seconds was considered "good," and development after 60 seconds was considered "poor." The results are shown in Table 2.

[0130] (2) Thermogravimetric testing

[0131] The heat resistance of photoimageable solder mask ink affects the maximum temperature at which it can be normally used, which can be characterized by the thermal decomposition temperature of its cured film. Therefore, the thermal gravimetric test curve of the cured film of photoimageable solder mask ink is obtained by thermogravimetric testing, and the temperature at which 5% mass loss occurs in the curve is used as the thermal decomposition temperature of the material (T d5％ The results are shown in Table 2.

[0132] (3) Pencil hardness

[0133] After the ink was cured by light and heat on a copper substrate, the pencil hardness of the cured film was measured using a BGD505 combination pencil hardness tester in accordance with GB / T6739-2022. The results are shown in Table 2.

[0134] (4) Pattern resolution

[0135] The resolution of the ink is characterized by observing the smallest dimension without overexposure under a microscope.

[0136] Use a microscope to observe the pattern clarity after development. The 60um opening without overexposure is "excellent".

[0137] The 60 μm aperture was overexposed and was rated "good," while the 60 μm aperture could not be developed and was rated "poor." The results are shown in Table 2.

[0138] (5) Storage performance

[0139] Seal the prepared solder mask ink photosensitive resin system in a clean, airtight container and store in a refrigerator at 4±2°C, away from light, for one month. Do not stir or open the lid during this period. After the storage period, observe the system for uniform appearance, delamination, precipitation, gelation, discoloration, or odor, and measure the viscosity change. Evaluate its storage stability according to the following standards. Excellent: No obvious change in the system appearance, uniform without delamination, precipitation, or gelation, and viscosity change of less than ±10%; Good: The system has slight delamination and can be restored to uniformity after simple stirring, and the viscosity change is between ±10–20%; Poor: The system has obvious delamination, gelation, precipitation, or odor, and the viscosity change exceeds ±50%, making it unusable.

[0140] (6) Copper peeling force test

[0141] 180° peel strength is an important indicator for measuring and evaluating the bonding performance of adhesive products. For each sample, the average peel strength is measured from the peel strength and peel length curve in N. The copper peel strength test is carried out in accordance with GB-T2790-1995. Figure 1 Shown in.

[0142] Peel strength calculation formula:

[0143] Table 2

[0144]

[0145]

[0146] As shown in Table 1, the difference between Ink Examples 1 to 4 and Ink Comparative Example 1 lies in the absence of carbamate groups in the acrylic photosensitive resin added to Ink Comparative Example 1, while the acrylic photosensitive resin added to Ink Examples 1 to 4 does contain carbamate groups. The test results in Table 2 indicate that the peel strength of the dry films prepared from Ink Examples 1 to 4 against copper is significantly higher than that of Ink Comparative Example 1. This indicates that the introduction of carbamate groups into the acrylic photosensitive resin improves the peel strength of dry films prepared from inks containing this acrylic photosensitive resin. Furthermore, Table 2 also indicates that the presence of carbamate groups in the acrylic photosensitive resin also improves the developing performance, pattern resolution, glass transition temperature, flexibility, Young's modulus, and storage properties of the inks containing this acrylic photosensitive resin. This is likely due to the molecular structure of the acrylic photosensitive resin containing carbamate groups, which exhibits a combination of carbamate and acrylate groups that strongly interact with each other in hydrogen bonding. Consequently, the resulting acrylic photosensitive resin containing carbamate groups exhibits excellent adhesion, heat resistance, and flexibility. The introduction of carbamate groups into the acrylate copolymer also improves its adhesion to substrates (e.g., copper substrates). Furthermore, the carbamate groups impart excellent chemical resistance to the ink, effectively protecting the substrate in acidic, alkaline, and organic solvent environments, thereby extending the service life of electronic components. The prepared photosensitive solder mask ink containing a carbamate-containing acrylic photosensitive resin exhibits excellent storage properties, maintaining good adhesion and rheological properties even after prolonged storage, thereby reducing waste during the production process and improving the economic and convenient manufacturing process.

[0147] The main difference between Example 1 and Example 4 is that the molar ratio of the functional unit having a side chain hydroxyl group to the acid anhydride compound and the isocyanate compound in the preparation raw material of the acrylic photosensitive resin containing a carbamate group is different. The molar ratio of the isocyanate compound to the functional unit having a side chain hydroxyl group in Examples 1 to 4 increases successively. When the molar ratio of the isocyanate compound to the functional unit having a side chain hydroxyl group is 0.2 to 0.4, the prepared photosensitive solder resist ink has better high resistance stability (T d5％ Greater than 310°C), and has better adhesion and flexibility. The above describes in detail the technical solutions provided in the embodiments of this application. Specific examples are used herein to illustrate the principles and implementation methods of this application. The description of the above embodiments is only intended to help understand the method and core concept of this application. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concepts of this application. In summary, the contents of this specification should not be construed as limiting this application.

Claims

1. An acrylic photosensitive resin containing a carbamate group, characterized in that: The raw materials for preparing the acrylic photosensitive resin containing carbamate groups include an acrylic ester copolymer containing hydroxyl groups on the side chains, an acid anhydride compound, and an isocyanate compound; wherein the acid anhydride compound can react with some hydroxyl groups on the side chains of the acrylic ester copolymer to obtain an acrylic ester grafted with the acid anhydride compound, and the isocyanate compound can react with some remaining hydroxyl groups on the side chains of the acrylic ester copolymer to obtain the acrylic photosensitive resin containing carbamate groups.

2. The acrylic photosensitive resin according to claim 1, wherein Calculated by molar amount, the ratio of unit A: the acid anhydride compound: the isocyanate compound is 1: (0.1-0.9): (0.1-0.9); And / or, the structure of the acrylic ester copolymer containing hydroxyl groups on the side chains is as shown in formula (1): Among them, unit A is the first functional unit that provides side chain hydroxyl groups; unit B is a toughening unit; unit C is a rigid unit; unit D is the second functional unit; n, p, q are positive integers or zero, and n, p, q cannot be 0 at the same time; m is a positive integer.

3. The acrylic photosensitive resin according to claim 2, wherein Calculated by mole, the ratio of the A unit: the B unit: the C unit: the D unit is (1-50): (10-50): (1-50): (1-50); preferably, the ratio of the A unit: the B unit: the C unit: the D unit is (18-22): (18-22): (8-12): (8-12); And / or, the ratio of the A unit: the acid anhydride compound: the isocyanate compound is 1: (0.6-0.9): (0.1-0.4).

4. The acrylic photosensitive resin according to claim 3, wherein Calculated in molar ratio, the A unit: the acid anhydride compound: the isocyanate compound is 1: (0.6-0.8): (0.2-0.4).

5. The acrylic photosensitive resin according to claim 2, wherein The monomer forming the A unit includes at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, hydroxypropyl acrylate, and hydroxypropyl methacrylate; and / or, the monomer forming the B unit includes at least one of cis-4-methyl-2-pentene, cis-3-hexene, polyethylene glycol methyl ether methacrylate, butyl methacrylate, isooctyl acrylate, hexyl methacrylate, undecyl methacrylate, 2-morpholinylethyl methacrylate, 6-methylheptyl acrylate, and 6-chlorohexyl methacrylate; and / or, the monomer forming the C unit includes at least one of styrene, α-methylstyrene, benzyl methacrylate, 2-phenoxyethyl methacrylate, styrene methacrylate, 1-ethylcyclohexyl methacrylate, and 3-phenoxybenzyl acrylate; and / or, the monomer forming the D unit includes, but is not limited to, at least one of pentabromobenzyl methacrylate, 9-anthracenemethyl acrylate, 2-(perfluorooctyl)ethyl methacrylate, methyl methacrylate, trimethylsilyl methacrylate, 1H,1H,2H,2H-nonafluorohexyl methacrylate, 2-naphthyl acrylate, and perfluoroalkylethyl acrylate; And / or, the acid anhydride compound includes but is not limited to one or more of tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, itaconic anhydride, maleic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, nadic anhydride, hexafluorinated phthalic anhydride, and anhydrous phthalic anhydride; And / or, the isocyanate compound includes but is not limited to at least one of octadecyl isocyanate, octyl isocyanate, butyl isocyanate, tert-butyl isocyanate, isocyanoethyl methacrylate, 3,3′-dimethyl-4,4′-dimethyl-4,4′-biphenyl diisocyanate, phenylene diisocyanate, 4,4′-biphenyl diisocyanate, trimethylhexamethylene diisocyanate, 4,4′-methylene-bis(2,6-diethylphenyl isocyanate), and isocyanatopropyltrimethoxysilane; And / or, the number average molecular weight of the acrylic ester copolymer containing hydroxyl groups on the side chains is 2,000-20,000.

6. The acrylic photosensitive resin according to any one of claims 1 to 5, characterized in that: The number average molecular weight of the acrylic photosensitive resin is 2000-20000; And / or, the weight average molecular weight of the acrylic photosensitive resin is 2000-20000; And / or, the PDI of the acrylic photosensitive resin is ≤2; And / or, the solid acid value of the acrylic photosensitive resin is 30 mgKOH / g-120 mgKOH / g.

7. A photosensitive resin composition, characterized in that The photosensitive resin composition comprises the acrylic photosensitive resin containing a carbamate group according to any one of claims 1 to 6.

8. A photosensitive solder resist ink, characterized in that: The photosensitive solder resist ink comprises the acrylic photosensitive resin containing a carbamate group according to any one of claims 1 to 6.

9. The photosensitive solder resist ink according to claim 8, wherein: The photosensitive solder resist ink further comprises at least one of a photosensitizer, a filler, a photoinitiator, a thermal curing agent, a pigment, a leveling agent, a defoaming agent, a thermal curing component, a photocrosslinking monomer and a third solvent.

10. The photosensitive solder resist ink according to claim 9, wherein: Calculated by mass, the photosensitive solder resist ink includes: 60 to 70 parts of the acrylic photosensitive resin containing a carbamate group; 0.01 to 0.1 parts of the photosensitizer; 20 to 35 parts of the filler; 1.8 to 2.8 parts of the photoinitiator; 15.0 to 23.1 parts of the heat curing component; 0.6 to 1.0 parts of the thermal curing agent; 0.1 to 1.0 parts of the pigment; 2.5 to 6.3 parts of the leveling agent; 0.25 to 0.5 parts of the defoaming agent; The photocrosslinking monomer is 7.5 to 15.0 parts.

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