Resin composition and cured film and application thereof

Abstract

The invention provides a resin composition as well as a cured film and application thereof. The resin composition comprises alkali-soluble acrylic resin, a photopolymerization monomer, a photoinitiator and a coloring agent, the coloring agent comprises modified TiO2, and the modified TiO2 is TiO2 which is subjected to graft modification by an isocyanate compound and a silane coupling agent. According to the invention, by grafting a small molecule compound with an isocyanate group on the surface of the titanium dioxide, the compatibility of the titanium dioxide is improved, and the crosslinking degree is improved; and the crosslinking degree and the heat resistance are improved through the reaction of isocyanate groups and hydroxyl groups in the system.

Description

Technical Field

[0001] The present invention relates to the technical field of printed circuit boards, in particular to a resin composition and a cured film thereof, and applications thereof. Background Art

[0002] During the printed circuit board (PCB) manufacturing process, solder mask is typically used to protect the circuitry on the substrate from the effects of solder and the harsh external environment. Due to PCB production requirements, solder mask layers must possess various properties, with heat resistance and flexibility being key. Poor heat resistance can lead to noticeable yellowing, resulting in a sharp drop in reflectivity and affecting the efficiency of LED light reflection. Poor flexibility can also cause the cured film to become brittle and difficult to bend, failing to meet the solder mask requirements of FPCs and R&FPCBs.

[0003] In order to improve the heat resistance of the solder mask layer, the crosslinking degree in the resin system is usually increased. There are roughly two approaches in the relevant technology: one is to promote the crosslinking degree between resins; the other is to promote the crosslinking degree between inorganic particles (fillers, etc.) and resins.

[0004] Titanium dioxide, a white pigment, is widely used in white solder mask dry film / ink to improve the dry film's yellowing resistance and reflectivity. However, titanium dioxide's surface is rich in hydroxyl groups, resulting in a large surface area, easy aggregation, and poor compatibility with resins. Furthermore, its high usage significantly affects the flexibility of the cured film, making it brittle and exhibiting poor folding resistance.

[0005] A Chinese patent document, published under the publication number CN116715993A, discloses a "process for preparing white solder mask for LEDs." This patent involves aminating titanium dioxide with KH550, then grafting the reactants onto its surface to produce an initiating titanium dioxide. Polymerization monomers are then added to produce the grafted titanium dioxide. This surface modification improves the dispersion and compatibility of titanium dioxide in the system and increases the degree of cross-linking. The resulting solder mask ink exhibits enhanced hardness, high-temperature resistance, and yellowing resistance.

[0006] Chinese patent literature discloses "a high-temperature resistant UV-curable solder resist ink and its preparation method", with publication number CN106916485A. This patent prepares solid aminoethylaminopropyl cage-type silsesquioxane as a cross-linking agent to increase the degree of cross-linking in the system, thereby improving the heat resistance and hardness of the light-curable solder resist ink.

[0007] Although both of the above-mentioned existing technologies improve the hardness and heat resistance of the cured product, the grafting reaction of the former is too complicated, while the latter uses a synthetic cross-linking agent to increase the degree of cross-linking. Both fail to improve the flexibility of the entire system.

[0008] In order to make the solder mask layer have both heat resistance and flexibility, and to improve the flexibility and folding resistance of the cured film, most industry experts modify or compound the resin, and rarely perform surface treatment on the filler / pigment.

[0009] Chinese patent literature discloses "a high-temperature resistant white ink and an LED substrate made thereof", with publication number CN115141511A. The patent provides a formula of a compound polyetherimide resin and a long-chain branched resin, which has characteristics such as high reflectivity and resistance to high-temperature yellowing. However, it has high cost, complex process, and general high-temperature resistance, and does not change the interfacial compatibility between titanium dioxide and the resin.

[0010] The World Intellectual Property Organization has published "CURABLE RESIN COMPOSITION, CURED PRODUCTTHEREOF AND PRINTED CIRCUIT BOARD USING SAME", with publication number WO2012141124A1. This patent provides a formula of a compounded carboxyl-containing polyurethane composition and an aromatic-ring-containing carboxyl-free resin, achieving a high balance between flexibility and high reflectivity. However, its flexibility still has room for improvement. Summary of the Invention

[0011] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a resin composition and a cured film thereof, and applications thereof, for solving the problems of poor heat resistance, brittleness, poor folding resistance, and inability to simultaneously achieve both heat resistance and flexibility in the cured films used for the solder mask layer of printed circuit boards.

[0012] To achieve the above-mentioned purpose and other related purposes, the present invention is obtained by including the following technical solutions.

[0013] The invention provides a resin composition, comprising an alkali-soluble acrylic resin, a photopolymerizable monomer, a photoinitiator and a colorant; the colorant comprises modified TiO2, which is TiO2 grafted with an isocyanate compound and a silane coupling agent.

[0014] In the above technical solution of the present application, the colorant creatively adopts TiO2 that has been grafted and modified by isocyanate compounds and silane coupling agents, and titanium oxide can be divided into rutile type and anatase type. Because anatase type titanium oxide has photocatalytic activity and will destroy the resin structure, rutile type titanium oxide is preferred. The preparation methods of rutile type titanium dioxide are divided into chlorination method and sulfuric acid method, and rutile type titanium dioxide prepared by chlorination method is preferred. Rutile type titanium oxide can provide high reflectivity and heat resistance. However, its surface is rich in hydroxyl groups, easy to agglomerate, and the amount used as a white pigment is extremely large, which affects the flexibility and crack resistance of the cured product. The surface of titanium dioxide is rich in hydroxyl groups, easy to agglomerate, and hydroxyl groups are hydrophilic and have poor compatibility with the system. Grafting small molecule compounds with isocyanate groups on the surface of titanium dioxide improves the compatibility of titanium dioxide and increases the degree of cross-linking. Other structures of small molecule compounds with isocyanate groups give titanium dioxide special functions. For example, chain segments with benzene rings give the solder mask dry film a higher hardness, and those with long alkyl chains can give the solder mask dry film better flexibility. Isocyanate small molecule compounds with both flexible structures such as long alkyl chains and rigid structures such as benzene rings can give the solder mask dry film a certain hardness and good flexibility. In addition, the cross-linking degree and heat resistance are improved by the reaction of isocyanate groups with hydroxyl groups in the system. However, TiO2 modified with isocyanate compounds alone does not improve the flexibility of the entire system. The present application further uses a silane coupling agent to graft modify the surface of TiO2 modified with isocyanate compounds, which can improve the dispersibility of titanium dioxide in the system and the interfacial interaction with the matrix, thereby improving the flexibility and crack resistance of the cured product, significantly improving the flexibility of the solder mask dry film, and will not reduce the reflectivity and heat resistance after reflow soldering, which can meet the needs of FPC white solder mask dry film.

[0015] Preferably, based on 100 parts by weight of the total weight, the resin composition includes the following components in parts by weight:

[0016] Preferably, the isocyanate compound includes one or more of rigid isocyanate, flexible isocyanate and rigid-flexible composite isocyanate.

[0017] More preferably, the rigid isocyanate comprises one or more of p-phenylene diisocyanate, toluene 2,6-diisocyanate, cyclohexane-1,4-diisocyanate, 4,4'-methylenebis(phenyl isocyanate), 4,4-diisocyanate dicyclohexylmethane, isophorone diisocyanate, and triphenylmethane triisocyanate; More preferably, the flexible isocyanate comprises one or more of hexamethylene diisocyanate, hexamethylene diisocyanate biuret, L-lysine triisocyanate and 1,4-diisocyanatobutane; More preferably, the rigid-flexible composite isocyanate comprises hexamethylene diisocyanate isocyanurate trimer.

[0018] Preferably, the isocyanate compound includes rigid isocyanate and flexible isocyanate.

[0019] More preferably, the molar ratio of the rigid isocyanate to the flexible isocyanate is (0.3-0.8):1.

[0020] Preferably, the TiO2 is selected from rutile or anatase, more preferably rutile.

[0021] Preferably, the alkali-soluble acrylic resin has urethane bonds and / or carboxyl groups, and will not break or crack on a flexible substrate, and has excellent crack resistance and flexibility.

[0022] More preferably, the alkali-soluble acrylic resin has a carboxyl group, and the alkali-soluble acrylic resin includes at least one of a urethane-modified epoxy resin and an aromatic urethane acrylate.

[0023] More preferably, the alkali-soluble acrylic resin has a urethane bond, including one or more of ether-type urethane compounds, ester-type urethane compounds, fluorine-modified urethane, silicon-modified urethane, modified urethane epoxy, modified urethane acrylate and epoxy-containing modified urethane epoxy acrylate.

[0024] More preferably, the alkali-soluble acrylic resin has a carboxyl group and can be obtained by purchasing a commercially available product. The alkali-soluble acrylic resin includes EPU-7N (urethane-modified epoxy resin; ADEKA Co., Ltd.); Ebecryl 210 (aromatic urethane acrylate; Daicel Allnex Co., Ltd.); and UXE-3000 (Nippon Chemical Pharmaceutical Co., Ltd.), preferably one or more of which are used in combination.

[0025] Preferably, the photopolymerizable monomer comprises an acrylate monomer composition having two or more functionalities.

[0026] More preferably, the photopolymerizable monomer includes one or more of diacrylates such as neopentyl glycol dimethacrylate, tetraethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and 1,6-hexanediol dimethacrylate, triacrylates such as trimethylolpropane trimethacrylate, pentaerythritol triacrylate, and ethoxylated trimethylolpropane triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, and dipentaerythritol pentaacrylate.

[0027] Preferably, the molar ratio of the silane coupling agent to the isocyanate compound is (0.3-0.7):1.

[0028] Preferably, the silane coupling agent is a silane coupling agent with a long alkyl chain.

[0029] More preferably, the silane coupling agent includes one or more of dodecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, octadecyldimethylmethoxysilane and octadecyltriethoxysilane.

[0030] Preferably, the photoinitiator includes one or more of bisacylphosphine oxide compounds, oxime ester compounds, titanocene compounds and α-aminoacetophenone compounds.

[0031] Preferably, the modified TiO2 is prepared by a method comprising the following steps: (1) dispersing an isocyanate compound and TiO2 in a first dispersion medium, and grafting isocyanate groups on the surface of TiO2 under the action of a catalyst; (2) dispersing the TiO2 with isocyanate groups grafted on the surface in water, adding an ethanol hydrolyzate of a silane coupling agent, and causing a condensation reaction under alkaline conditions to graft the silane coupling agent on the surface of the TiO2 with isocyanate groups to obtain the modified TiO2.

[0032] More preferably, in step (1), the mass ratio of the isocyanate compound to TiO2 is 1:(1-2) More preferably, in step (1), the dispersion medium is acetone.

[0033] More preferably, in step (1), the catalyst is dibutyl dilaurate; and the reaction temperature is 55-65°C.

[0034] More preferably, in step (2), the condensation reaction temperature is 35-45° C., and the reaction time is 1.5-2.5 h.

[0035] More preferably, in step (2), the mass ratio of the silane coupling agent to the titanium dioxide with isocyanate groups grafted on the surface is (0.1-0.2):1.

[0036] More preferably, the bisacylphosphine oxide compound includes one or more of 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide and bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

[0037] More preferably, the oxime ester compound includes one or both of ethyl ketone 1-9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl-1-(O-acetyl oxime) and 1,2-octanedione-1-4-(phenylthio)-2-(O-benzoyl oxime).

[0038] More preferably, the titanocene compound includes one or more of bis(cyclopentadienyl)-di-phenyl-titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyl-1-yl)ethyl)phenyl]titanium and bis(η-5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium.

[0039] More preferably, the α-aminoacetophenone compound includes one or more of 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1 and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butane-1-one.

[0040] Preferably, the colorant further includes one or more of aluminum oxide, zinc oxide, titanium oxide and zirconium oxide.

[0041] Preferably, the resin composition further comprises 4 to 8 parts of a thermosetting component.

[0042] More preferably, the thermosetting component includes one or more of bisphenol A type, brominated epoxy resin, novolac type, bisphenol F type, hydrogenated bisphenol A type, glycidylamine type, hydantoin type, ester ring type, trishydroxyphenylmethane type, bisphenol S type, bisphenol A novolac type and dicyclopentadiene type epoxy resin.

[0043] Preferably, the resin composition further comprises 0.1 to 1 parts of a curing agent.

[0044] Preferably, the curing agent includes one or more of imidazole derivatives, amine compounds, phosphorus compounds and s-triazine derivatives.

[0045] More preferably, the imidazole derivative includes one or more of imidazole, 2-methylimidazole, 2-phenylimidazole and 1-cyanoethyl-2-phenylimidazole.

[0046] More preferably, the amine compound includes one or more of dicyandiamide, 4-methyl-N,N-dimethylbenzylamine, and 4-(dimethylamino)-N,N-dimethylbenzylamine.

[0047] More preferably, the phosphorus compound is triphenylphosphine; More preferably, the s-triazine derivatives include one or more of melamine, guanamine, methylguanamine, 2-vinyl-2,4-diamino-s-triazine, and 2-vinyl-4,6-diamino-s-triazine isocyanuric acid adduct.

[0048] Preferably, the resin composition further comprises 0.01 to 1 part of an additive, wherein the additive comprises one or more of an antioxidant, a dispersant and a leveling agent.

[0049] The leveling agent can reduce the surface tension of the liquid, so that the resin composition forms a uniform film on the carrier film with good gloss and smoothness.

[0050] Preferably, the antioxidant includes one or more of phenolic compounds, quinone compounds and amine compounds.

[0051] More preferably, the phenolic compound includes one or more of 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,-6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 4-tert-butylcatechol, 2,2-methylene-bis-(4-methyl-6-tert-butylphenol) and p-methoxyphenol.

[0052] More preferably, the quinone compound includes one or both of hydroquinone monomethyl ether and benzoquinone.

[0053] More preferably, the amine compound includes bis(2,2,6,6-tetramethyl-4-piperidinyl)-sebacate.

[0054] More preferably, the dispersant includes one or more of phosphates, carboxyl-containing polycarboxylic acid esters, long-chain polyaminoamides, and the like.

[0055] More preferably, the leveling agent includes one or more of acrylic compounds, silicone compounds, and fluorocarbon compounds.

[0056] Preferably, the resin composition further comprises 2 to 20 parts of a solvent.

[0057] More preferably, the solvent includes one or more of ketone compounds, glycol ether compounds, aromatic hydrocarbon compounds, ester compounds, aliphatic hydrocarbons and petroleum solvents.

[0058] More preferably, the ketone compound includes one or both of methyl ethyl ketone and cyclohexanone.

[0059] More preferably, the glycol ether compound includes one or more of methyl cellosolve, methyl carbitol, butyl carbitol, and diethylene glycol monomethyl ether acetate.

[0060] More preferably, the aromatic hydrocarbon compound includes one or both of toluene and tetramethylbenzene.

[0061] More preferably, the ester compound includes one or more of ethyl acetate, cellosolve acetate, butyl cellosolve acetate, and propylene glycol monomethyl ether acetate.

[0062] More preferably, the aliphatic hydrocarbon compound includes one or both of the aliphatic hydrocarbons octane and decane.

[0063] More preferably, the petroleum-based solvent includes one or both of petroleum ether and naphtha.

[0064] The above solvents can be used alone or in combination.

[0065] The present invention also provides a cured film, which is obtained by curing the above resin composition.

[0066] The present invention also provides an application of the resin composition or cured film, wherein the resin composition or cured film is used for manufacturing printed circuit boards, lead frames and semiconductor package substrates.

[0067] As described above, the resin composition of the present invention, its cured film, and its application have the following beneficial effects: a small molecule compound with an isocyanate group is grafted onto the surface of titanium dioxide, thereby improving the compatibility of titanium dioxide and increasing the degree of crosslinking; the degree of crosslinking and heat resistance are increased by the reaction of the isocyanate group with the hydroxyl group in the system. The surface of TiO2 modified with an isocyanate compound is grafted with a silane coupling agent, significantly improving the flexibility of the solder resist dry film without reducing the reflectivity and heat resistance after reflow soldering, thereby meeting the requirements of FPC white solder resist dry film. The cured film obtained after curing the resin composition of the present application has both heat resistance and flexibility, and can be used in the manufacture of printed circuit boards, lead frames, and semiconductor packaging substrates. DETAILED DESCRIPTION

[0068] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0069] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0070] Furthermore, it should be understood that the one or more method steps mentioned in the present invention do not exclude the presence of other method steps before or after the combination step, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise specified. It should also be understood that the combination connection relationship between one or more devices / apparatuses mentioned in the present invention does not exclude the presence of other devices / apparatuses before or after the combination device / apparatus, or the insertion of other devices / apparatuses between two explicitly mentioned devices / apparatuses, unless otherwise specified. Furthermore, unless otherwise specified, the numbering of each method step is merely a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the present invention. Changes or adjustments to their relative relationships, without substantially changing the technical content, should also be considered within the scope of the present invention.

[0071] Each embodiment and comparative example of the present application provides a resin composition, the specific formula of which is shown in Table 1, wherein the colorant is modified TiO2, and the modified TiO2 is TiO2 that is sequentially grafted with an isocyanate compound and a silane coupling agent.

[0072] The mechanism by which TDI is grafted onto the surface of titanium dioxide through the reaction of isocyanate groups with hydroxyl groups on the surface of titanium dioxide is as follows:

[0073] The mechanism by which the silane coupling agent with a long alkyl chain is grafted onto the titanium dioxide surface through the condensation of the silane group and the hydroxyl group on the titanium dioxide surface to form a Si-O-Ti bond is as follows:

[0074] Example 1 The present invention provides a resin composition, which comprises the following components in parts by weight based on 100 parts by weight: The types of components are selected according to Table 1 and Table 2. The colorant is rutile TiO2 grafted with an isocyanate compound and a silane coupling agent. The preparation method includes the following steps: (1) In a flask equipped with a thermometer, a stirrer, a dropping funnel and a reflux cooler, 50 parts of rutile titanium dioxide are dispersed in 1000 parts by weight of acetone at room temperature; then, p-phenylene diisocyanate is dissolved in acetone and 1 wt% of dibutyl dilaurate is used as a catalyst and dropped into the titanium dioxide acetone dispersion. The mixed solution is stirred at 60°C for 16 hours, and the isocyanate-modified TiO2 nanoparticles are separated by centrifuge at 5000 rpm and purified by repeated washing with toluene; the final white hybrid network is obtained after vacuum drying at 85°C for 6 hours, and isocyanate groups are grafted on the TiO2 surface; the weight ratio of isocyanate compound to rutile TiO2 is controlled to be 1:1; (2) In a flask equipped with a thermometer, a stirrer, a dropping funnel and a reflux cooler, 50 parts of titanium dioxide modified in step (1) and 1 part of sodium hexametaphosphate are ultrasonically dispersed in 450 parts by weight of deionized water at room temperature, and 3.75 parts of ammonia water are slowly added dropwise; after ultrasonic dispersion is uniform, 6 parts of dodecyltrimethoxysilane are slowly added dropwise and the temperature is raised to 40°C and ultrasonically reacted for 2 hours; after the grafting modification is completed, the dispersion is filtered, and then washed with anhydrous ethanol several times, filtered and dried under warm wind conditions at 40°C to obtain rutile TiO2 grafted with an isocyanate compound and a silane coupling agent.

[0075] Examples 2 to 9 The difference between Examples 2 to 9 and Example 1 is that the colorants are different, namely D2 to D10 in Table 1, and the other components are exactly the same.

[0076] Example 10 The difference between Example 10 and Example 1 is that the proportions of the components are different, specifically: The types of components are selected according to Table 1 and Table 2.

[0077] Example 11 The difference between Example 11 and Example 1 is that the proportions of the components are different, specifically: 8 parts of thermosetting components 1 part curing agent The types of components are selected according to Table 1 and Table 2.

[0078] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the colorant is rutile TiO2 that has not undergone any modification, named D1, and the other components are exactly the same.

[0079] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the colorant is rutile TiO2 modified only with an isocyanate compound, named D11, and the other components are exactly the same.

[0080] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the colorant is rutile TiO2 that has only been modified with a silane coupling agent and is named D12, and the other components are exactly the same.

[0081] Table 1. Colorant correspondence table Table 2. Formulas of Examples 1 to 11 and Comparative Examples 1 to 3 In Table 2: Component A: commercially available alkali-soluble acrylic resin; A1: Aromatic urethane acrylate; (Ebecry 210; Daicel Allnex Co., Ltd.); A2 urethane acrylate (ADEKA Co., Ltd., EPU-7N); Component B, photopolymerizable monomer; B1: ethoxylated trimethylolpropane triacrylate; B2: dipentaerythritol pentaacrylate; Component C, photoinitiator; C1: 2,4,6-trimethylbenzoyldiphenylphosphine oxide; (Changzhou Qiangli, TR-TPO); C2: bis(2,6-difluoro-3-pyrrolphenyl)titanium ocene (BASF JAPAN LTD, CGI-784); C3: 1-(6-o-methylbenzoyl-9-ethyl-9.H-carbazol-3-yl)-ethanone oxime-0-acetate (BASF JAPAN LTD, OXE02); Component D is titanium dioxide as shown in Table 1; D1: titanium dioxide, rutile type; (Ishihara Corporation, CR-90); D2-D8: rutile TiO2 grafted with isocyanate compounds and silane coupling agents in sequence; D9: Anatase TiO2 modified by isocyanate compound and silane coupling agent in sequence D10: Rutile TiO2 modified by isocyanate compound only; D11: Rutile TiO2 modified with silane coupling agent only; E: bisphenol A epoxy resin; (Mitsubishi Chemical, JER828); F: curing agent; F1: melamine; (Aladdin, amine curing agent); F2: 4,4'-diaminodiphenyl sulfone; (Aladdin, amine curing agent); G1: Antioxidant; (BASF, 1010); G2: dispersant; (BYK Chemical, Disperbyk-110); G3: Leveling agent; (Bick Chemical, ); Solvent S1: γ-butyrolactone; According to the formulations in Table 2, cured films were prepared, including the following steps: 1) Preparation of photosensitive resin composition Components A, D, and G were added to γ-butyrolactone in a specific ratio and stirred evenly. The mixture was then sanded to a particle size of <5 μm. The ground dispersion was then evenly mixed with the remaining components. The resin composition was evenly coated onto a PET film using a coater. The film was then dried in an 85°C oven for 30 minutes. The resulting film was then covered with a PP protective film to produce a 38 μm thick dry solder mask.

[0082] Transfer the product to the film laminating section, tear off the PP protective film, and use a vacuum laminating machine (vacuum section: pressure 4-5kgf, vacuum time 20-40s, pressing time: 30-50s, temperature 60-80°C. Leveling section: pressure 4-5kgf, vacuum time 20-40s, pressing time: 30-50s, temperature 70-80°C) to press the solder mask dry film product onto the commercial copper clad laminate.

[0083] Exposure, development and thermal curing of dry film solder mask products The resin composition prepared in 1) was peeled from the PET and exposed to appropriate energy levels using an exposure machine. The exposed resin composition was allowed to stand at room temperature for 30 minutes, then developed with an alkaline developer (1% wt sodium carbonate aqueous solution) for 30-60 seconds. The surface was then rinsed with clean water to ensure that any residual developer was completely removed. The dried copper-clad laminate with the resin composition was then placed in a 150°C oven for curing for 1 hour.

[0084] Sensitivity: The lowest energy at which the ST21-step exposure scale is exposed and developed and the ST8-step is not developed and is fully exposed is recorded as the sensitivity energy of the formula.

[0085] 3) Reflectivity The compositions of the above-described embodiments and comparative examples were coated on PET using an applicator to a film thickness of 38 μm. The films were dried at 85°C for 30 min and then attached to a copper plate. The films were then baked at 150°C for 60 min to obtain cured films. The reflectivity at a wavelength of 460 nm was measured using a spectrophotometer (CM-2600d, manufactured by Konica Minolta Sensing, Inc.).

[0086] ◎: Reflectivity above 90% ⊙: Reflectivity is 80% or more and less than 90% △: Reflectivity is 70% or more and less than 80% ×: Reflectivity is less than 70% 4) Reflectivity after reflow soldering The preparation method 1) was used, and the process was repeated three times in a reflow oven (maximum 285° C.). The reflectivity at a wavelength of 460 nm was measured using a spectrophotometer (CM-2600d, manufactured by Konica Minolta Sensing, Inc.).

[0087] ◎: Reflectivity above 90% ⊙: Reflectivity is 80% or more and less than 90% △: Reflectivity is 70% or more and less than 80% ×: Reflectivity is less than 70% 5)Welding heat resistance Each component of the above examples and comparative examples was coated onto PET using an applicator to a film thickness of 38 μm. The film was then baked at 150°C for 60 minutes to obtain a cured film. The resulting cured film was then immersed in a solder bath at 260°C, and the surface condition of the cured film was observed.

[0088] <Judgment criteria for soldering heat resistance> ◎: No peeling was observed even after immersion for 10 seconds was repeated twice.

[0089] ⊙: When the immersion was repeated twice for 10 seconds, slight peeling occurred.

[0090] ×: Peeling occurred after one 10-second immersion.

[0091] 6) Flexibility (bending test) Using the preparation method in 2), the curled seam of the obtained cured film was repeatedly bent 180° multiple times, and the cracks in the coating film were observed by visual inspection or an optical microscope with a magnification of 20. The number of times no cracks were generated was measured.

[0092] <Flexibility Judgment Criteria> ◎: 6 or more times ⊙: 4 to 5 times or more △: 2 to 3 times ×: Less than 1 time 7) Acid resistance: Using the preparation method 1), the dried cured film was exposed to light (or a mask with a small amount of circuitry was used for exposure) at ST8 / 21 sensitivity. After 30 minutes of exposure, the film was developed and baked at 150°C for 60 minutes to obtain a cured film. The prepared sample was immersed in a 10 vol% H2SO4 aqueous solution at 30°C for 30 minutes, then rinsed with water and dried. A peel test was then performed using 3M tape.

[0093] <Acid resistance judgment criteria> ◎: No blistering, peeling, or even falling off; ⊙: A small amount of blistering occurs, but there is no peeling or falling off; △: A small amount of blistering, peeling, or even falling off occurs; ×: A large amount of shedding occurred.

[0094] 8) Alkali resistance: Using the preparation method 4), the prepared sample was immersed in a 10 vol% NaOH aqueous solution at 30° C. for 30 minutes, then rinsed with clean water and dried. A peel test was then performed using 3M tape.

[0095] <Acid resistance judgment criteria> ◎: No blistering, peeling, or even falling off; ⊙: A small amount of blistering occurs, but there is no peeling or falling off; △: A small amount of blistering, peeling, or even falling off occurs; ×: A large amount of shedding occurred.

[0096] 9) Solvent resistance: Using the preparation method 4), the prepared sample was immersed in propylene glycol methyl ether acetate solvent at 30°C for 30 minutes, removed, rinsed with clean water, and dried. A peel test was then performed using 3M tape.

[0097] <Acid resistance judgment criteria> ◎: No blistering, peeling, or even falling off; ⊙: A small amount of blistering occurs, but there is no peeling or falling off; △: A small amount of blistering, peeling, or even falling off occurs; ×: A large amount of shedding occurred.

[0098] 10) Dielectric loss (Df) and dielectric constant (Dk) testing: At 25° C. and 50% RH, the cured resin compositions of the examples and comparative examples were tested for dielectric loss and dielectric constant using a resonator (Agilent E5071BENA) with the aid of a separated dielectric resonator (SPDR) method. 11) HAST test: Using the preparation method 2), the resistivity of the cured product before HAST treatment was measured using a resistance meter. The sample was then transferred to a HAST chamber (PC-422R8D, Hirayama Seisakusho). After 120 hours of storage at 100% humidity and 121°C, the resistivity of the sample was measured. The surface condition of the sample was observed, and the resistivity change before and after treatment was compared.

[0099] ◎: No bubble peeling or other phenomena occur, or the resistivity changes within ±10%; ⊙: No bubble peeling or other phenomena occur, or the resistivity changes within ±30%; △: The dry film has a small amount of bubbling, peeling, or even falling off; ×: There are a lot of bubbles or peeling, or the resistivity changes by more than 50%.

[0100] The test data is shown in Table 3: Table 3. Performance test results of the cured films of Examples 1 to 11 and Comparative Examples 1 to 3 As can be seen from the above table, by referring to the data of Examples 1 to 9, the present application uses TiO2 grafted and modified by isocyanate compounds and silane coupling agents as a colorant to compound with other components, and the final cured film obtained takes into account both heat resistance and flexibility, among which rutile TiO2 has a better effect than anatase TiO2; by comparing the data of Example 1 and Comparative Example 1, it can be seen that directly using rutile TiO2 without any modification as a colorant to compound with other components, the final cured film has poor heat resistance and flexibility. This is because the surface of titanium dioxide is rich in hydroxyl groups, which is easy to agglomerate, and the hydroxyl groups are hydrophilic, resulting in poor compatibility with the system; by comparing the data of Example 1 and Comparative Example 2, it can be seen that only grafting a small molecule compound with an isocyanate group on the surface of titanium dioxide improves the compatibility of titanium dioxide and increases the crosslinking degree and heat resistance, but the flexibility of the solder resist dry film is very poor; by comparing the data of Example 1 and Comparative Example 3, it can be seen that only grafting a silane coupling agent on the surface of titanium dioxide significantly improves the flexibility of the solder resist dry film, but the crosslinking degree of the system is low and the heat resistance is poor.

[0101] The above examples are intended to illustrate the embodiments disclosed herein and are not to be construed as limiting the present invention. In addition, the various modifications listed herein and variations of the methods and compositions in the invention will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. Although the present invention has been specifically described in conjunction with various specific preferred embodiments of the present invention, it should be understood that the present invention should not be limited to these specific embodiments. In fact, various modifications apparent to those skilled in the art as described above to obtain the invention should be included within the scope of the present invention.

Claims

1. A resin composition, characterized in that The invention comprises an alkali-soluble acrylic resin, a photopolymerizable monomer, a photoinitiator and a colorant; the colorant comprises modified TiO2, which is TiO2 grafted and modified by an isocyanate compound and a silane coupling agent.

2. The resin composition according to claim 1, wherein: Based on 100 parts by weight of the total, the following components are included:

3. The resin composition according to claim 1, wherein: The isocyanate compound includes one or more of rigid isocyanate, flexible isocyanate and rigid-flexible composite isocyanate; Preferably, the rigid isocyanate comprises one or more of p-phenylene diisocyanate, toluene 2,6-diisocyanate, cyclohexane-1,4-diisocyanate, 4,4'-methylenebis(phenyl isocyanate), 4,4-diisocyanate dicyclohexylmethane, isophorone diisocyanate and triphenylmethane triisocyanate; More preferably, the flexible isocyanate comprises one or more of hexamethylene diisocyanate, hexamethylene diisocyanate biuret, L-lysine triisocyanate and 1,4-diisocyanatobutane; More preferably, the rigid-flexible composite isocyanate comprises hexamethylene diisocyanate isocyanurate trimer.

4. The resin composition according to claim 3, wherein: The isocyanate compound includes rigid isocyanate and flexible isocyanate. Preferably, the molar ratio of the rigid isocyanate to the flexible isocyanate is (0.3-0.8):

1.

5. The resin composition according to claim 1, wherein: The TiO2 is selected from rutile or anatase, preferably rutile; and / or the alkali-soluble acrylic resin has a urethane bond and / or a carboxyl group; preferably, the alkali-soluble acrylic resin has a carboxyl group, and the alkali-soluble acrylic resin includes at least one of a urethane-modified epoxy resin and an aromatic urethane acrylate; and / or the photopolymerizable monomer comprises an acrylate monomer composition having two or more functionalities; preferably, the photopolymerizable monomer comprises one or more of diacrylates such as neopentyl glycol dimethacrylate, tetraethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, and dipentaerythritol pentaacrylate; and / or the silane coupling agent is a silane coupling agent having a long alkyl chain, preferably, the silane coupling agent includes one or more of dodecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, octadecyldimethylmethoxysilane and octadecyltriethoxysilane; And (or) the photoinitiator includes one or more of bisacylphosphine oxide compounds, oxime ester compounds, titanocene compounds and α-aminoacetophenone compounds.

6. The resin composition according to any one of claims 1 to 5, characterized in that: The modified TiO2 is prepared by a method comprising the following steps: (1) dispersing an isocyanate compound and TiO2 in a first dispersion medium, and grafting isocyanate groups on the surface of the TiO2 under the action of a catalyst; preferably, the mass ratio of the isocyanate compound to the TiO2 is 1:(1-2); (2) dispersing the surface-grafted isocyanate-grouped TiO2 in water, adding an ethanol hydrolyzate of a silane coupling agent, and grafting the silane coupling agent on the surface of the surface-grafted isocyanate-grouped TiO2 to obtain the modified TiO2; preferably, the mass ratio of the silane coupling agent to the surface-grafted isocyanate-grouped titanium dioxide is (0.1-0.2):

1.

7. The resin composition according to claim 1, wherein: The resin composition also includes 4 to 8 parts of a thermosetting component, and the thermosetting component includes one or more of bisphenol A type, brominated epoxy resin, novolac type, bisphenol F type, hydrogenated bisphenol A type, glycidylamine type, hydantoin type, ester ring type, trihydroxyphenylmethane type, bisphenol S type, bisphenol A novolac type and dicyclopentadiene type epoxy resin.

8. The resin composition according to claim 1, wherein: The resin composition further comprises 0.1 to 1 part of a curing agent, wherein the curing agent comprises one or more of an imidazole derivative, an amine compound, a phosphorus compound and an s-triazine derivative; and (or) the resin composition further comprises 0.01 to 1 parts of an additive, wherein the additive comprises one or more of an antioxidant, a dispersant and a leveling agent; And / or the resin composition further comprises 2 to 20 parts of a solvent, wherein the solvent comprises one or more of ketone compounds, glycol ether compounds, aromatic hydrocarbon compounds, ester compounds, aliphatic hydrocarbon compounds and petroleum solvents.

9. A cured film, characterized in that The resin composition according to any one of claims 1 to 8 is cured.

10. Use of the resin composition according to any one of claims 1 to 8 or the cured film according to claim 9, characterized in that: The resin composition or cured film is used for manufacturing printed circuit boards, lead frames and semiconductor package substrates.

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