Light-cured resin as well as preparation method and application thereof

Abstract

The invention relates to the technical field of resin synthesis, in particular to light-cured resin as well as a preparation method and application thereof. The light-cured resin is prepared from the following raw materials in parts by weight: 200 to 300 parts of resin A, 15 to 30 parts of resin B, 2 to 4 parts of a catalyst, 0.1 to 0.5 part of a polymerization inhibitor I, 60 to 100 parts of an acrylic acid compound, 50 to 130 parts of acid anhydride and 150 to 300 parts of a solvent I, the molecular structure of the light-cured resin contains an active reaction group; the active reaction groups comprise carboxyl, double bonds and hydroxyl. The epoxy resin with specific functions is introduced, and the specific acrylic acid and the solvent are matched for combined action, so that the performance of the light-cured resin is improved; the obtained photosensitive solder resist dry film has the advantages of high resolution, high flexibility, reliable chemical resistance, short exposure time and the like, and can meet the use requirements of electronic components.

Description

Technical Field

[0001] This invention relates to the field of resin synthesis technology, and in particular to a photocurable resin, its preparation method, and its application. Background Technology

[0002] As electronic products become increasingly sophisticated and performance-oriented, the limitations of traditional liquid solder resist inks in terms of coating uniformity, thickness control, and environmental friendliness are becoming more and more prominent. Existing photosensitive solder resist dry films have many defects, such as insufficient adhesion, increased local stress due to curing shrinkage, poor adhesion to substrates such as copper-clad laminates and tin-plated laminates, and easy peeling after soldering; poor chemical resistance, insufficient stability under high and low temperature, acid and alkali, salt spray and other conditions, and long-term storage will corrode the dry film layer, failing to perform its circuit protection function. Driven by technological innovation, solder resist dry film technology with higher adhesion and chemical resistance has emerged.

[0003] With the trend of high-density and high-frequency development of circuit boards, higher requirements are placed on the adhesion, thermal shock resistance, and dielectric properties of solder resist materials. The performance requirements of solder resist dry film mainly include: 1) Good heat resistance: thermodynamic softening temperature of 105–110℃, solder resistance to 260℃ for 10 seconds without bubbling, Tg>120℃, coefficient of thermal expansion<100ppm / k, and no warping under high and low temperature impact; 2) Reliable chemical resistance: resistant to chemical reagents (such as nickel-palladium-gold solutions, cleaning agents, acid and alkali solutions); 3) Good mechanical properties: strong adhesion, resistance to repeated high-temperature soldering, good flexibility, not easily scratched or damaged, and high resolution of solder bridge (suitable for small-pitch pads); 4) Good process and environmental performance: curing rate>85%, stable color after curing without yellowing, easy peeling of PET protective layer by electrostatic adsorption, impact resistance, and UV protection; shelf life of 12 months, coating area of ​​15m² / L (15μm dry film thickness), halogen-free formula (bromine content<900ppm), low VOC (<28g / m²), and compliant with RoHS, REACH and other directives.

[0004] Optimizing the formulation of photocurable dry films (such as adding adhesion promoters and low dielectric constant materials) can improve the performance of solder resist dry films. With the rapid development of the electronics industry, the performance requirements for photosensitive solder resist dry films are becoming increasingly stringent. To meet these demands, engineers have begun to research and improve film-forming resins. For example, by designing the molecular structure and composition of the film-forming resin, its compatibility with other components can be improved, thereby enhancing the film-forming and mechanical properties of the dry film; by adding special monomers or additives, the physical strength, reactivity, and chemical stability of the dry film can be improved; and by compounding inorganic fillers with different coefficients of thermal expansion, the coefficient of thermal expansion of the dry film can be reduced, and the glass transition point can be increased. However, existing solder resist dry films still cannot simultaneously meet the requirements for developability, adhesion, and mechanical properties. Chinese invention patent application CN120230289A discloses an alkali-soluble photocurable resin, its preparation method, and a photocurable resin composition. By introducing an imide structure into the alkali-soluble photocurable resin, it solves the problems of insufficient thermomechanical properties and compatibility with polyimide resins, achieving improved thermodynamic properties and better overall performance. Chinese invention patent application CN119039569A discloses a method for preparing a modified epoxy photocurable resin. This method involves reacting polyetheramine with acryloyl chloride to generate an amine-modified prepolymer, followed by chain extension with a polymerization inhibitor. This solves the problems of high viscosity and poor toughness in existing modified epoxy acrylates, producing a modified epoxy photocurable resin with low viscosity and high toughness, maintaining hardness and heat resistance while improving the flexibility and gloss of the cured film. However, these existing technologies do not solve the aforementioned technical problems; the resulting resin cannot simultaneously possess high adhesion, reliable chemical resistance, and photosensitivity, thus failing to meet application requirements.

[0005] Against this backdrop, in order to meet the ever-evolving needs of the electronics industry, it is imperative to develop high-performance photocurable resins suitable for IC substrates to achieve domestic substitution of solder resist dry films. Summary of the Invention

[0006] To address the aforementioned technical problems and optimize the shortcomings of existing photosensitive solder resist dry films, such as poor photosensitivity, flexibility, chemical resistance, high coefficient of thermal expansion (CTE), and low glass transition temperature, this invention provides a photocurable resin, its preparation method, and its application. By introducing a specific functional epoxy resin into the photocurable resin, its flexibility, photosensitivity, glass transition point, and chemical resistance are improved, and production efficiency is increased.

[0007] The first aspect of the present invention provides a photocurable resin, wherein the raw materials for preparing the photocurable resin, by weight, include: 200-300 parts of resin A, 15-30 parts of resin B, 2-4 parts of catalyst, 0.1-0.5 parts of polymerization inhibitor, 60-100 parts of acrylic compound, 50-130 parts of acid anhydride and 150-300 parts of solvent.

[0008] Optionally, the molecular structure of the photocurable resin contains reactive groups; the reactive groups include carboxyl groups, double bonds, and hydroxyl groups.

[0009] Optionally, resin A includes epoxy resin, which includes one or more combinations of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic epoxy resin, halogenated epoxy resin, glycidyl ester epoxy resin, glycidyl amine type epoxy resin, and aliphatic epoxy resin.

[0010] Optionally, the epoxy resin includes phenolic epoxy resin, and more preferably cresol phenolic epoxy resin.

[0011] The acrylic compound includes acrylic acid or methacrylic acid; it may further be acrylic acid.

[0012] The catalyst may include triphenylphosphine, triethylamine, tetrabutylammonium bromide, benzyl dimethylamine, etc.; optionally, the catalyst includes triphenylphosphine.

[0013] Optionally, the acid anhydride includes one or more combinations of sulfuric anhydride, nitric anhydride, carbonic anhydride, acetic anhydride, tetrahydrophthalic anhydride, maleic anhydride, benzoic anhydride, pyromellitic dianhydride, biphenyl dianhydride, cyclobutane dianhydride, 3,3',4,4'-benzophenone dianhydride, 1,4,5,8-naphthalene dianhydride, 3,3',4,4'-diphenyl ether dianhydride, 1,2,3,4-cyclopentane dianhydride, and 3,3',4,4'-diphenyl sulfone dianhydride; further optionally, it includes one or more combinations of sulfuric anhydride, nitric anhydride, carbonic anhydride, acetic anhydride, tetrahydrophthalic anhydride, maleic anhydride, and benzoic anhydride; even more preferably, it is tetrahydrophthalic anhydride.

[0014] Optionally, the polymerization inhibitor includes one or more of hydroquinone, p-benzoquinone, p-tert-butylcatechol, methylene blue, cuprous chloride, ferric chloride, sodium tert-butoxide, and 1,1-diphenyl-2-picrylhydrazine (DPPH); further optionally, it is hydroquinone.

[0015] The solvent can include, for example, hydrocarbon solvents, ketone solvents, halogenated hydrocarbon solvents, ether solvents, alcohol solvents, ester solvents, and water.

[0016] Optionally, the solvent one includes one or more of toluene, acetone, butanone, dichloromethane, dichloroethane, trichloroethane, chloroform, dioxane, methyl ethyl ketone, methanol, ethanol, ethyl acetate, butyl acetate, xylene, diethyl ether, propylene glycol methyl ether, ethylene glycol methyl ether, propylene glycol methyl ether acetate, and water; further optionally, it is propylene glycol methyl ether acetate.

[0017] Optionally, the resin B includes a polyurethane acrylate resin.

[0018] Optionally, the raw materials for preparing the polyurethane acrylate resin include: hydroxyl-containing acrylate, diisocyanate, polymerization inhibitor II, and solvent II.

[0019] The hydroxyl-containing acrylate may include, for example, 4-hydroxybutyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyhexyl acrylate, hydroxyoctyl acrylate, hydroxydecyl acrylate, and hydroxylauryl acrylate; and may further be selected as hydroxyethyl acrylate.

[0020] The diisocyanate may include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), etc.; IPDI may be selected.

[0021] The solvent 2 can be listed as toluene, acetone, butanone, dichloromethane, dichloroethane, trichloroethane, chloroform, dioxane, methyl ethyl ketone, methanol, ethanol, ethyl acetate, butyl acetate, xylene, diethyl ether, propylene glycol methyl ether, ethylene glycol methyl ether, propylene glycol methyl ether acetate, etc.; toluene may be selected as the solvent 2.

[0022] In some embodiments, the raw materials for preparing resin B also include a catalyst.

[0023] Optionally, the preparation steps of resin B include: adding diisocyanate and polymerization inhibitor II to solvent II, mixing evenly, heating to 85-95℃, adding hydroxyl-containing acrylate dropwise for 1-5 hours, and maintaining the temperature for 3-7 hours to obtain resin B.

[0024] The raw materials for preparing solder resist dry films typically include acrylic resin, acrylate monomers, photocurable resin, thermocurable resin, photoinitiator, curing agent, filler, colorant, and solvent. The performance of the dry film is optimized by modifying the acrylic resin (e.g., by adding photocurable functional groups, acid-modified resin, etc.) and adjusting the selection and proportions of other components. Improving the adhesion of the photocurable dry film can solve product quality problems caused by curing shrinkage, making it suitable for dense circuit boards. However, existing improvement methods cannot simultaneously provide solder resist dry films with flexibility, chemical stability, and photosensitivity. This invention uses cresol phenolic epoxy resin, polyurethane acrylate resin, acrylic acid, and other raw materials to synthesize a specifically functionalized photocurable resin, and combines it with a specific solvent (propylene glycol methyl ether acetate) to prepare a photocurable resin with high Tg (glass transition temperature), viscosity, and molecular weight. The resulting photocurable resin, when applied to solder resist dry films, can simultaneously improve the flexibility, chemical resistance, and photosensitivity of the solder resist dry film, enabling it to meet the requirements of electronic component applications.

[0025] A second aspect of the present invention provides a method for preparing the photocurable resin as described above, wherein the preparation steps of the photocurable resin include: S1. Mix 20-60% of the formulation amount of solvent one with resin A. After resin A is completely dissolved, add catalyst and polymerization inhibitor one, and mix evenly. S2. Heat to 90-100℃ and add acrylic monomer to react for 6-15 hours; S3. Cool to 80-90℃, add acid anhydride and resin B, and react for 4-10 hours; S4. Add the remaining solvent I, and dilute to obtain the light-cured resin.

[0026] In some embodiments, step S1 includes: adding 20-60% of the formulation amount of solvent one into the reaction apparatus, adding resin A under stirring at 100-400 rpm, raising the temperature to 80-95°C and turning on the reflux of cooling water to ensure the stability of the reaction temperature; after resin A is completely dissolved and mixed evenly with solvent one, adding catalyst and polymerization inhibitor one, and mixing evenly.

[0027] Optionally, in step S2, the acrylic monomer is added dropwise, and the dropwise addition time is controlled within 2 hours; further, it can be 1 hour.

[0028] Optionally, the acid anhydride is added dropwise in step S3.

[0029] In some embodiments, the preparation steps of the photocurable resin include: S1. Add 20-60% of the solvent amount of the formula to the flask, add resin A through the funnel under stirring at 200 rpm, heat to 90℃ and turn on the reflux of the cooling water to ensure the stability of the reaction temperature; after resin A is completely dissolved and mixed evenly with the solvent, add the catalyst and polymerization inhibitor, and mix evenly.

[0030] S2. Heat to 95℃ and add acrylic monomer dropwise through a dropping funnel (complete the addition in 1 hour), and react for 12 hours; S3. Cool to 85℃, add acid anhydride and resin B dropwise through a funnel, and react for 6 hours; S4. Add the remaining solvent I, and dilute to obtain the light-cured resin.

[0031] A third aspect of the present invention provides an application of the photocurable resin as described above, wherein the photocurable resin is applied to a photosensitive solder resist coating, and the raw materials for preparing the photosensitive solder resist coating, by weight, include: 10-40 parts of thermocurable resin, 60-110 parts of photocurable resin, 2-5 parts of photoinitiator, 1-3 parts of pigment, 0.1-5 parts of additives, and 2-10 parts of filler.

[0032] Optionally, the filler is an inorganic filler, such as barium sulfate, calcium carbonate, and silicon dioxide. The additives can be added flexibly according to application needs, such as leveling agents, defoamers, diluents, antibacterial agents, etc.

[0033] Optionally, the preparation steps of the photosensitive solder resist coating include: mixing thermosetting resin, photocuring resin, photoinitiator, pigment, additives and filler, stirring evenly to obtain a photosensitive solder resist composition, diluting the photosensitive solder resist composition, mixing evenly to obtain a photosensitive solder resist coating.

[0034] A fourth aspect of the present invention provides a photosensitive solder resist dry film, which is formed by curing the photosensitive solder resist coating as described above.

[0035] Optionally, the curing method is as follows: applying photosensitive solder resist coating to the surface of the carrier film and baking and curing at 105-120℃ for 5-20 minutes to obtain a photosensitive solder resist dry film.

[0036] Optionally, the Tg of the photosensitive solder resist dry film is ≥120℃; further optionally, the Tg of the photosensitive solder resist dry film is ≥135℃.

[0037] The fifth aspect of this invention provides an application of the photocurable resin described above, wherein the photocurable resin can also be used in photoresist; the amount of photocurable resin added to the photoresist is 60-80 wt%. The photocurable resin prepared by this invention can improve the chemical resistance, photosensitivity, insulation, and environmental friendliness of photoresist.

[0038] Beneficial effects: This invention provides a photocurable resin, its preparation method, and its application, which have the following advantages: (1) The present invention prepares a photocurable resin by introducing a specific function of epoxy resin, and the combination of a specific acrylic acid and solvent improves the molecular weight, solid content, Tg and viscosity of the photocurable resin; the solder resist dry film prepared by the photocurable resin of the present invention has excellent performance. (2) By adding a photocurable resin containing a variety of active reactive groups to the photosensitive solder resist coating, the photosensitive solder resist dry film has the advantages of high resolution, high flexibility, reliable chemical resistance and short exposure time, which can meet the requirements of electronic components. (3) The present invention further optimizes the formulation system of photosensitive solder resist coating, significantly reduces the exposure time and exposure energy of the product, enabling it to be rapidly exposed at a lower exposure energy to achieve a higher exposure level, significantly improving the production efficiency of downstream end, and has broad application prospects. (4) The raw materials of the present invention are readily available, the preparation method is simple, and the implementation is strong. Detailed Implementation

[0039] The following describes the implementation of the present invention with reference to specific embodiments. Those skilled in the art can understand the technical concept of the present invention based on the content disclosed in this specification. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] The resin A (cresol epoxy resin) used in the various embodiments of the present invention is sourced from Nan Ya Plastics Group in Taiwan, China, and its model number is NPCN-704.

[0041] The resin B used in the various embodiments of the present invention is a polyurethane acrylate resin (self-made); by weight, the raw materials for preparing the polyurethane acrylate resin include: 30 parts of hydroxyl-containing acrylate (hydroxyethyl acrylate), 40 parts of diisocyanate (IPDI), 0.5 parts of polymerization inhibitor di (hydroquinone), 2 parts of triphenylphosphine and 30 parts of solvent di (toluene).

[0042] The preparation steps of resin B include: adding solvent II to the reaction apparatus, starting the stirrer, then adding diisocyanate, polymerization inhibitor II and triphenylphosphine, mixing evenly and heating to 90°C, adding hydroxyl-containing acrylate dropwise for 3 hours, and keeping the reaction at the temperature for 5 hours after the dropwise addition is completed to obtain resin B.

[0043] The bisphenol A epoxy resin used in the various embodiments of the present invention is sourced from Chang Chun Chemical Co., Ltd. in Taiwan, China, and its model number is BE188EL.

[0044] Unless otherwise specified, all raw materials, equipment and other consumables used in this invention are commercially available.

[0045] Example 1 This embodiment provides a photocurable resin, its preparation method, and its application.

[0046] The raw materials for preparing the photocurable resin, by weight, include: 250 parts resin A (cresol phenolic epoxy resin), 15 parts resin B (polyurethane acrylate resin), 2 parts catalyst (triphenylphosphine), 0.1 parts polymerization inhibitor one (hydroquinone), 80 parts acrylic compound (acrylic acid), 119 parts acid anhydride (tetrahydrophthalic anhydride), and 200 parts solvent one (propylene glycol methyl ether acetate).

[0047] The molecular structure of the photocurable resin contains reactive groups; the reactive groups include carboxyl groups, double bonds, and hydroxyl groups.

[0048] The preparation steps of the photocurable resin include: S1. Add 50% (100 parts) of the formulation of solvent one into the flask, add resin A through a funnel while stirring at 200 rpm, heat to 90°C and turn on the reflux of the cooling water to ensure the stability of the reaction temperature; after resin A is completely dissolved and mixed evenly with solvent one, add catalyst and polymerization inhibitor one, and mix evenly.

[0049] S2. Heat to 95℃ and add acrylic monomer dropwise through a dropping funnel (complete the addition in 1 hour), and react for 12 hours; S3. Cool to 85℃, add acid anhydride and resin B dropwise through a funnel, and react for 6 hours; S4. Add the remaining solvent I, and dilute to obtain the light-cured resin.

[0050] The photocurable resin is used in photosensitive solder resist coatings. By weight, the raw materials for preparing the photosensitive solder resist coatings include: 25 parts thermosetting resin (bisphenol A type epoxy resin), 90 parts of the above-mentioned photocurable resin, 2 parts photoinitiator (Irgacure 369), 1 part pigment (phthalocyanine green), 1.5 parts additive (silicone defoamer, Huaxiong Technology Co., Ltd., model MH8299), 4 parts filler (barium sulfate), and 0.5 parts diluent (TMPTA, trimethylolpropane triacrylate).

[0051] The preparation steps of the photosensitive solder resist coating include: mixing thermosetting resin, photocuring resin, photoinitiator, pigment, additives, and filler, stirring evenly to obtain a photosensitive solder resist composition, adding solvent (butanone) to dilute the photosensitive solder resist composition, and mixing evenly to obtain a photosensitive solder resist coating.

[0052] The photosensitive solder resist coating is applied to the surface of the carrier film and baked at 110°C for 10 minutes to obtain a photosensitive solder resist dry film.

[0053] The carrier film is made of PET and has a coating thickness of 40 μm (dry film).

[0054] Example 2 This embodiment provides a photocurable resin, its preparation method, and its application. The specific implementation method is the same as in Embodiment 1; the difference is that, by weight, the raw materials for preparing the photocurable resin include: 250 parts of resin A (cresol phenolic epoxy resin), 15 parts of resin B (polyurethane acrylate resin), 2 parts of catalyst (triphenylphosphine), 0.1 parts of polymerization inhibitor one (hydroquinone), 72 parts of acrylic compound (acrylic acid), 119 parts of acid anhydride (tetrahydrophthalic anhydride), and 196.4 parts of solvent one (butanone).

[0055] In step S1, the amount of solvent one added is 100 parts; In step S4, the amount of solvent 1 added is 96.4 parts.

[0056] Example 3 This embodiment provides a photocurable resin, its preparation method, and its application. The specific implementation method is the same as in Embodiment 1; the difference is that the amount of acrylic acid added is 72 parts, and the amount of resin B added is 30 parts.

[0057] Example 4 This embodiment provides a photocurable resin, its preparation method, and its application. The specific implementation method is the same as in Embodiment 1; the difference is that the amount of acrylic acid added is 72 parts, and the acid anhydride is specifically maleic anhydride.

[0058] Example 5 This embodiment provides a photocurable resin, its preparation method, and its application. The specific implementation method is the same as in Embodiment 1; the difference is that the raw materials for preparing the photocurable resin do not include resin B.

[0059] Performance testing 1. Properties of UV-curable resins The performance indicators of the photocurable resins prepared in Examples 1-5 were tested, and the test results are shown in Table 1.

[0060] Table 1

[0061] 2. Performance of photosensitive solder resist dry film The performance indicators of the photosensitive solder resist dry films prepared in Examples 1-5 were tested, and the test results are shown in Table 2. The test methods for each performance are as follows: 1. Acid value The method for testing acid value is as follows: 1.1 First, mix 10g of ethanol and 40g of butanone, add 1g of the photosensitive solder resist dry film prepared in Examples 1-5, and then add 3-4 drops of phenolphthalein solution; 1.2 The sample was titrated using a KOH aqueous solution, according to the formula... Calculate the acid value of the sample; 1.3 Result Judgment; Judgment criteria are as follows: Passed: Acid value ≥100mgKOH / g; Failed: Acid value < 100 mg KOH / g.

[0062] 2. Photomeability The test method for radioactivity is as follows: 2.1 The photosensitive solder resist dry film prepared in Examples 1-5 was laminated onto the surface of a copper foil substrate and dried by heating at 100°C for 30 minutes; 2.2 The sample substrate was fully exposed using a negative film at a specified exposure level (600 mJ / cm²); 2.3 A 1 wt% sodium carbonate aqueous solution was used as the developing solution, with a spray pressure of 2 kg / cm². 2 Under the specified conditions, development was performed for 1 minute, and the development effect was observed using a metallurgical microscope. The criteria for judging the development effect are as follows: A: Even minute details on the substrate surface can be fully developed; B: There are a few areas on the substrate surface that cannot be fully developed; C: A large portion of the substrate surface cannot be fully developed; D: Almost impossible to develop.

[0063] 3. Resolution The method for testing resolution is as follows: 3.1 The photosensitive solder resist dry film prepared in Examples 1-5 is laminated onto the surface of a copper foil substrate; 3.2 Full exposure of the sample substrate using the optimal exposure energy with a negative film; 3.3 A 1 wt% sodium carbonate aqueous solution was used as the developing solution, with a spray pressure of 2 kg / cm². 2 Under the specified conditions, the circuit was developed for 1 minute and observed using a metallographic microscope. The results were judged based on the resolution standard. The resolution data in Table 2 represent the accuracy of the circuit after development. Insufficient accuracy will result in incomplete development.

[0064] 4. Photosensitivity The method for testing photosensitivity is as follows: 4.1 The photosensitive solder resist dry film prepared in Examples 1-5 is laminated onto the surface of a copper foil substrate; 4.2 Use 42-strip exposure negative film and expose the dry film with different exposure energies; 4.3 A 1 wt% sodium carbonate aqueous solution was used as the developing solution, with a spray pressure of 2 kg / cm². 2 Develop for 1 minute under the specified conditions; 4.4 Observe the exposure level of the sample, record the exposure energy required to reach exposure level 19, and determine the photosensitivity of the dry film; the determination criteria are as follows: To achieve exposure level 19, the required exposure energy is ≤200 mJ / cm². 2 ; Fail: The required exposure energy to reach exposure level 19 is >200 mJ / cm². 2 .

[0065] 5. Flexibility Methods for testing flexibility: 5.1 Under yellow light conditions, a small section of the photosensitive solder resist dry film prepared in Examples 1-5 was taken and stretched using a tensile testing machine; 5.2 The flexibility of the sample is judged by comparing the ratio of the elongation at break to the original length (i.e., elongation at break) of the dry film when it breaks under tensile force. The judgment criteria are as follows: no cracks after 25 cycles of bending with an inner diameter of 3.18 mm are considered as passing, and cracks are considered as failing.

[0066] Table 2

[0067] As can be seen from the data in Tables 1 and 2, this invention prepares a photocurable resin by introducing a specific functional epoxy resin, and through the combined action of a specific acrylic acid and solvent, improves the molecular weight, Tg, viscosity, and solid content of the photocurable resin. The solder resist dry film obtained by formulating the photocurable resin of this invention exhibits excellent comprehensive performance, possessing both excellent flexibility and developability. The dry film has good photosensitivity, enabling exposure to be completed in a short time, thus improving production efficiency. It also has a good acid value, providing reliable chemical stability to the product. By adding fillers, photoinitiators, and pigments to the solder resist coating system, the resolution can be improved to 60 μm. Furthermore, experiments have verified that the solder resist dry film of this invention has advantages such as safety and environmental friendliness, good flexibility, good chemical resistance, low coefficient of thermal expansion (CTE), and high Tg. Compared to competing products, the solder resist dry film prepared by this invention exhibits superior resolution and adhesion.

Claims

1. A photocurable resin, characterized by, The raw materials for preparing the photocuring resin include, by weight, 200-300 parts of resin A, 15-30 parts of resin B, 2-4 parts of catalyst, 0.1-0.5 parts of polymerization inhibitor I, 60-100 parts of acrylic compound, 50-130 parts of acid anhydride, and 150-300 parts of solvent I; The photocuring resin contains active reaction groups in the molecular structure; the active reaction groups include carboxyl, double bond, and hydroxyl.

2. The photocurable resin according to claim 1, characterized in that, The resin A includes epoxy resin, which includes one or more of a combination of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic epoxy resin, halogenated epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, and aliphatic epoxy resin.

3. The photocurable resin according to claim 2, characterized in that, The resin A includes cresylic phenolic epoxy resin.

4. The light-cured resin of claim 1, wherein, The solvent I includes one or more of a combination of toluene, acetone, butanone, dichloromethane, dichloroethane, trichloroethane, chloroform, dioxane, methyl ethyl ketone, methanol, ethanol, ethyl acetate, butyl acetate, xylene, diethyl ether, propylene glycol methyl ether, ethylene glycol methyl ether, propylene glycol methyl ether acetate, and water.

5. The photocurable resin according to claim 4, characterized in that, The solvent I includes propylene glycol methyl ether acetate.

6. The light-cured resin of claim 1, wherein, The acid anhydride includes one or more of a combination of sulfuric anhydride, nitric anhydride, carbonic anhydride, acetic anhydride, tetrahydrophthalic anhydride, maleic anhydride, benzoic anhydride, pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, cyclobutane tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride, and 3,3',4,4'-diphenyl sulfone tetracarboxylic dianhydride.

7. A method of producing the photocurable resin according to any one of claims 1 to 6, characterized by, The preparation steps of the photocuring resin include: Mixing the solvent I and resin A in a formula amount of 20-60%, adding the catalyst and polymerization inhibitor I after the resin A is completely dissolved, and uniformly mixing; Raising the temperature to 90-100°C, adding the acrylic monomer, and reacting for 6-15h; Lowering the temperature to 80-90°C, adding the acid anhydride and resin B, and reacting for 4-10h; Adding the remaining solvent I, diluting, and obtaining the photocuring resin.

8. Use of a photocured resin according to any one of claims 1 to 6, characterized in that, The photocuring resin is applied to a photosensitive solder resist coating; the raw materials for preparing the photosensitive solder resist coating include, by weight, 10-40 parts of thermocuring resin, 60-110 parts of photocuring resin, 2-5 parts of photoinitiator, 1-3 parts of pigment, 0.1-5 parts of additive, and 2-10 parts of filler.

9. A photosensitive solder resist dry film, characterized by, The photosensitive solder resist dry film is formed by curing the photosensitive solder resist coating of claim 8.

10. Use of a photocured resin according to any one of claims 1 to 6, characterized in that, The photocuring resin is applied to a photoresist; the addition amount of the photocuring resin in the photoresist is 60-80wt%.

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