A solder mask dry film resistant to chemical reagents and its preparation method

Abstract

The present invention discloses a solder mask dry film resistant to chemical reagents and a preparation method thereof. By weight, the raw materials for preparation include: 15-20 parts of modified acrylic resin A, 15-30 parts of modified acrylic resin B, 10-20 parts of acrylic monomers, 1-5 parts of organosiloxane, 1-5 parts of photoinitiator, 5-15 parts of curing agent, 50-400 parts of titanium dioxide, 10-30 parts of solvent, and 1-10 parts of additives. The solder mask dry film prepared by the present invention has good leveling property, is used for the white solder mask layer of Mini LED reflective circuit boards, has good thickness uniformity of the solder mask layer, a reflectivity greater than 95%, and is resistant to chemical reagent treatment, such as immersion gold solution.

Description

Technical Field

[0001] The present invention relates to the technical field of G03F, and particularly relates to a solder mask dry film resistant to chemical reagents and a preparation method thereof. Background Art

[0002] A solder mask is a coated film used to provide dielectric and mechanical shielding during and after the soldering process. It can be in liquid or dry film form. In the manufacturing process of printed circuit boards (PCBs), the coating of solder mask ink is a very critical process, and its main functions include: protecting the circuit, preventing electrical short circuits between conductors caused by moisture or chemicals, preventing open circuits caused by improper handling during the subsequent processes of PCB production and electrical assembly, and protecting the PCB from various harsh environments. The market prospect of LED (light-emitting diode) display products is currently booming, and various types of LED products are emerging in an endless stream. The solder mask has a huge impact on the performance of LED products. Especially with the miniaturization and portability of mobile terminals, the preparation of solder masks for miniLEDs is currently a research hotspot.

[0003] CN106398386B discloses a solder mask ink for an LED exposure machine and a preparation method thereof. The ink mainly consists of a photosensitive material, an acrylic monomer, an epoxy resin, a pigment, a filler, a photoinitiator, an auxiliary agent, and a solvent. After uniformly dispersing the raw materials and grinding them, the finished ink is obtained through filtration, which is particularly suitable for an LED exposure machine. The solder mask ink disclosed in this patent uses toxic and carcinogenic chemical substances such as benzene and esters, which pose a safety hazard to the human body, and is not suitable for miniLEDs, with poor chemical reagent resistance.

[0004] CN101356475B discloses a photocurable and thermosetting solder resist composition and a printed circuit board using the same, which contains a carboxyl group-containing resin without an aromatic ring, a photopolymerization initiator, a hydrogenated epoxy compound, rutile titanium oxide, and a diluent. The solder mask disclosed in this patent has a high reflectivity and high heat resistance, but poor chemical reagent resistance. Summary of the Invention

[0005] In view of the above problems, the present invention discloses a solder mask dry film resistant to chemical reagents. By weight, the preparation raw materials include: 15 - 20 parts of modified acrylic resin A, 15 - 30 parts of modified acrylic resin B, 10 - 20 parts of acrylic monomer, 1 - 5 parts of organosiloxane, 1 - 5 parts of photoinitiator, 5 - 15 parts of curing agent, 50 - 400 parts of titanium dioxide, 10 - 30 parts of solvent, and 1 - 10 parts of auxiliary agent.

[0006] In one embodiment, the modified acrylic resin A is a modified acrylic resin containing a photocurable functional group.

[0007] Preferably, the photocurable functional group is a polyol.

[0008] Preferably, the modified acrylic resin A is selected from one or more of polyethylene glycol diacrylate, polypropylene glycol diacrylate, dipropylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and bisphenol A ethoxylate diacrylate.

[0009] More preferably, the modified acrylic resin A is neopentyl glycol diacrylate.

[0010] The neopentyl glycol diacrylate is polymerized from neopentyl glycol diacrylate monomer, and the average molecular weight is between 5000 and 10000.

[0011] In one embodiment, the modified acrylic resin B is a modified epoxy acrylate resin.

[0012] Preferably, the modified epoxy acrylate resin is bisphenol A epoxy acrylate resin.

[0013] In one embodiment, the acrylic monomer is selected from one or more of α-furanacrylic acid, methacrylic acid, acrylic acid, lauryl methacrylate, isobornyl methacrylate, isooctyl acrylate, isooctadecyl acrylate, 2-hydroxyethyl methacrylate, isobutyl acrylate, trimethylolpropane trimethacrylate, methoxy tripropylene glycol monoacrylate, and methoxypropoxy neopentyl glycol monoacrylate.

[0014] Preferably, the acrylic monomer is α-furanacrylic acid.

[0015] In one embodiment, the curing agent is one or more combinations of aliphatic amine curing agents, amidoamine curing agents, dicyandiamide curing agents, and isocyanate curing agents.

[0016] Preferably, the curing agent is an isocyanate curing agent.

[0017] The applicant found in experiments that when using neopentyl glycol diacrylate and bisphenol A epoxy acrylate simultaneously and adding α-furan acrylic acid, the solder mask dry film prepared can improve the mechanical properties of the dry film and can also improve the chemical corrosion resistance of the solder mask dry film. The applicant believes that the reason is that the polyols in neopentyl glycol diacrylate and bisphenol A epoxy acrylate further undergo a photocuring reaction under the action of a photoinitiator, increasing the molecular weight and crosslinking degree. The epoxy in bisphenol A epoxy acrylate and the furan in α-furan acrylic acid undergo a crosslinking reaction under the action of an isocyanate curing agent, increasing the crosslinking degree of the system, thereby enhancing its stability, improving the mechanical properties, and with the increase of the crosslinking degree, the porosity of the system can be reduced, and corrosive substances are not easily introduced into the interior of the material, thus improving the corrosion resistance ability.

[0018] In one embodiment, the organosiloxane is selected from one or more of phenylmethyltrimethyl polysiloxane, 1,3-bis(3-methacryloxypropyl)tetramethyldisiloxane, 1,3-dibenzyltetramethyldisiloxane, polydimethylsiloxane, vinyltrimethoxysilane, allyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidyletheroxypropyltrimethoxysilane, γ-methacryloyloxytrimethoxysilane, γ-methacryloxytrimethoxysilane.

[0019] Preferably, the organosiloxane is vinyltrimethoxysilane.

[0020] The applicant found in experiments that the solder mask dry film prepared by adding organosiloxane has better chemical corrosion resistance, high temperature resistance and mechanical properties. The applicant believes that the reason is that both neopentyl glycol diacrylate and bisphenol A epoxy acrylate are unsaturated resins, and the unsaturated double bonds therein are easily oxidized by oxygen in air or moisture, thereby changing the substance structure and deteriorating, resulting in it being more easily corroded by chemical reagents. After adding organosiloxane, especially vinyltrimethoxysilane containing double bonds, it can polymerize with monomers to form chemical crosslinks, and introduce Si-O bonds into the polymer main chain. Its bond energy is large, surface energy is low, and molecular chain flexibility is large, which can improve the stability of the polymer, reduce the polarity of the system, and thus enhance the chemical corrosion resistance. The applicant also found that the added vinyltrimethoxysilane contains ethoxy groups with large steric hindrance, which can adjust the hydrolysis and condensation rate of monomers in polymerization, and the resulting polymer has a high silane content and more excellent chemical resistance.

[0021] In one embodiment, the photoinitiator is a photoinitiator that can induce double bond coupling under light irradiation, and is selected from benzoin, acetophenone, benzophenone, anthraquinone, ɑ-aminobenzophenone, acylphosphine oxides, oxime esters, etc.

[0022] Preferably, the photoinitiator is selected from one or more of 2-methyl-1-(4-methylthiophenyl)-2-morpholin-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinobenzylphenyl)butanone, 2-isopropylthioxanthone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, bis(2,6-difluoro-3-pyrrolylphenyl)titanocene dichloride, and 2,4-diethylthioxanthone.

[0023] More preferably, the photoinitiator is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0024] In one embodiment, the titanium dioxide is rutile titanium dioxide.

[0025] Preferably, the mass percentage of the rutile titanium dioxide in the total raw material components is 50-80%.

[0026] The rutile titanium dioxide is purchased from Longmang Bailian Group, and the model is Xuelian R-996.

[0027] Adding titanium dioxide can improve the reflectance of the solder mask dry film and further enhance the comprehensive performance of the solder mask dry film. The applicant found in the experiment that the addition amount of titanium dioxide has a great influence on the chemical resistance. When the addition amount is greater than 80%, the curing ability becomes poor and the chemical resistance becomes poor. When the addition amount is less than 50%, the reflectance of the system cannot be guaranteed.

[0028] In one embodiment, the solvent is selected from: ketones, alcohols, esters, ethers, benzenes, petroleum solvents, etc.

[0029] Preferably, the solvent is selected from petroleum solvents, including but not limited to one or more of No. 90, No. 100, No. 120, No. 150, and No. 200 solvent oils.

[0030] More preferably, the solvent is No. 200 solvent oil.

[0031] In one embodiment, the additives include one or more combinations of antioxidants, plasticizers, tackifiers, dispersants, and inhibitors.

[0032] Preferably, the additives are antioxidants and inhibitors.

[0033] Preferably, the antioxidant is selected from one or several of antioxidant 300, antioxidant 1076, and antioxidant 168.

[0034] More preferably, the antioxidant is antioxidant 1076.

[0035] Preferably, the inhibitor is selected from at least one of hydroquinone, p-benzoquinone, methyl hydroquinone, p-methoxyphenol, 2-tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, and p-methoxyphenol.

[0036] More preferably, the inhibitor is hydroquinone.

[0037] The second aspect of the present invention provides a method for preparing the solder resist dry film resistant to chemical reagents: after mixing and stirring the raw materials for preparing the solder resist dry film, it is coated on a substrate material and hardened to obtain it.

[0038] Beneficial effects:

[0039] 1. In the present invention, under the action of a photoinitiator, the polyol in polyneopentyl glycol diacrylate and bisphenol A epoxy acrylate is further crosslinked, improving the molecular weight and chemical reagent resistance performance.

[0040] 2. In the present invention, bisphenol A epoxy acrylate and α-furan acrylic acid undergo a crosslinking reaction under the action of an isocyanate curing agent, improving the mechanical properties, reducing the porosity of the system, and making it difficult for corrosive substances to enter the material interior, thus improving the chemical reagent resistance ability.

[0041] 3. The present invention adds organosiloxane to polymerize with monomers to form chemical crosslinks, introducing Si-O bonds, improving stability, reducing the polarity of the system, and enhancing the chemical reagent resistance performance.

[0042] 4. The present invention adds titanium dioxide to improve the reflectance of the solder resist dry film, and controls the percentage of its addition amount to be 50-80% of the total raw material components, without affecting the curing ability and chemical resistance.

[0043] 5. The solder resist dry film prepared in this application does not contain halogens, is green and environmentally friendly, has good leveling property, is used for the white solder resist layer of Mini LED reflective circuit boards, has good thickness uniformity of the solder resist layer, a reflectance greater than 95%, and is resistant to chemical reagent treatment, such as gold plating solution. Specific Embodiments

[0044] Example 1

[0045] One aspect of Example 1 of the present invention discloses a solder resist dry film resistant to chemical reagents. Calculated by mass, the raw materials for preparation include: 15 parts of polyneopentyl glycol diacrylate, 30 parts of bisphenol A epoxy acrylate, 10 parts of α-furan acrylic acid, 1 part of vinyltrimethoxysilane, 1 part of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 5 parts of isocyanate curing agent, 350 parts of titanium dioxide, 10 parts of No. 200 solvent oil, 1 part of antioxidant 1076, and 0.5 part of hydroquinone.

[0046] The polyneopentyl glycol diacrylate is polymerized from neopentyl glycol diacrylate itself, and the average molecular weight is between 5000 and 10000.

[0047] The bisphenol A epoxy acrylate resin is purchased from Jinan Lanjue Trading Co., Ltd., and the model number is 71281-65-7.

[0048] The isocyanate curing agent is purchased from Wanhua Chemical, and the model number is HT-600.

[0049] The titanium dioxide is purchased from Longmang Bailian Group, and the model number is Xuelian R-996.

[0050] The No. 200 solvent oil is purchased from Shandong Chuangying Chemical Co., Ltd., and the model number is D200.

[0051] In the second aspect of Example 1 of the present invention, a preparation method of the solder resist dry film capable of resisting chemical reagents is disclosed: after mixing and stirring the raw materials for preparing the solder resist dry film, it is coated and hardened on a substrate material to obtain the solder resist dry film.

[0052] Example 2

[0053] In one aspect of Example 2 of the present invention, a solder resist dry film capable of resisting chemical reagents is disclosed. By mass, the raw materials for preparation include: 20 parts of polyneopentyl glycol diacrylate, 15 parts of bisphenol A epoxy acrylate resin, 20 parts of α-furan acrylic acid, 5 parts of vinyltrimethoxysilane, 5 parts of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 15 parts of isocyanate curing agent, 120 parts of titanium dioxide, 30 parts of No. 200 solvent oil, 3 parts of antioxidant 1076, and 7 parts of hydroquinone.

[0054] The polyneopentyl glycol diacrylate is polymerized from neopentyl glycol diacrylate itself, and the average molecular weight is between 5000 and 10000.

[0055] The bisphenol A epoxy acrylate resin is purchased from Jinan Lanjue Trading Co., Ltd., and the model number is 71281-65-7.

[0056] The isocyanate curing agent is purchased from Wanhua Chemical, and the model number is HT-600.

[0057] The titanium dioxide is purchased from Longmang Bailian Group, and the model number is Xuelian R-996.

[0058] The No. 200 solvent oil is purchased from Shandong Chuangying Chemical Co., Ltd., and the model number is D200.

[0059] In the second aspect of Example 2 of the present invention, a preparation method of the solder resist dry film capable of resisting chemical reagents is disclosed: after mixing and stirring the raw materials for preparing the solder resist dry film, it is coated and hardened on a substrate material to obtain the solder resist dry film.

[0060] Example 3

[0061] In Example 3 of the present invention, a solder mask dry film resistant to chemical reagents is disclosed. By mass, the preparation raw materials include: 18 parts of neopentyl glycol diacrylate, 28 parts of bisphenol A epoxy acrylate resin, 16 parts of α-furan acrylic acid, 3.5 parts of vinyltrimethoxysilane, 2.5 parts of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 9 parts of isocyanate curing agent, 300 parts of titanium dioxide, 23 parts of No. 200 solvent oil, 2.5 parts of antioxidant 1076, and 3 parts of hydroquinone.

[0062] The neopentyl glycol diacrylate is polymerized from the neopentyl glycol diacrylate itself, and the average molecular weight is 5000-10000.

[0063] The bisphenol A epoxy acrylate resin is purchased from Jinan Lanjue Trading Co., Ltd., and the model is 71281-65-7.

[0064] The isocyanate curing agent is purchased from Wanhua Chemical, and the model is HT-600.

[0065] The titanium dioxide is purchased from Longmang Bailian Group, and the model is Xuelian R-996.

[0066] The No. 200 solvent oil is purchased from Shandong Chuangying Chemical Co., Ltd., and the model is D200.

[0067] In the second aspect of Example 3 of the present invention, a preparation method of the solder mask dry film resistant to chemical reagents is disclosed: after mixing and stirring the preparation raw materials of the solder mask dry film, it is coated and hardened on the substrate material to obtain the product.

[0068] Example 4

[0069] Example 4 of the present invention provides a solder mask dry film resistant to chemical reagents. The specific implementation method is the same as that of Example 3, except that: by mass, the preparation raw materials include: 46 parts of bisphenol A epoxy acrylate resin, 16 parts of α-furan acrylic acid, 3.5 parts of vinyltrimethoxysilane, 2.5 parts of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 9 parts of isocyanate curing agent, 300 parts of titanium dioxide, 23 parts of No. 200 solvent oil, 2.5 parts of antioxidant 1076, and 3 parts of hydroquinone.

[0070] Example 5

[0071] Example 5 of the present invention provides a solder mask dry film resistant to chemical reagents. Its specific implementation is the same as that of Example 3, except that: by mass, the preparation raw materials include: 18 parts of neopentyl glycol diacrylate, 28 parts of bisphenol A epoxy acrylate, 16 parts of isooctadecyl acrylate, 3.5 parts of vinyltrimethoxysilane, 2.5 parts of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 9 parts of isocyanate curing agent, 300 parts of titanium dioxide, 23 parts of No. 200 solvent oil, 2.5 parts of antioxidant 1076, and 3 parts of hydroquinone.

[0072] Example 6

[0073] Example 6 of the present invention provides a solder mask dry film resistant to chemical reagents. Its specific implementation is the same as that of Example 3, except that: the organosiloxane is γ-methacryloxypropyltrimethoxysilane.

[0074] Performance test:

[0075] The white solder mask dry films obtained in Examples 1-6 were respectively laminated on the Mini LED board, then exposed, then developed in a 1wt% sodium carbonate aqueous solution for 60 s, and then cured at 150 °C for 60 min.

[0076] 1. Reflectance test: The reflectance was tested after passing through the SMT nitrogen oven three times, and the wavelength was 450 nm. The results are shown in Table 1 below.

[0077] 2. Flatness test:

[0078] a) Lamination: At 75 °C under a vacuum laminator, with a vacuum of 25 s and a lamination time of 30 s.

[0079] Levelling: The pressure is 0.6 kg / cm 2 , and the levelling time is 60 s.

[0080] After the dry film is laminated on the PCB surface, it is photocured, and the DI exposure machine is 1500 mj and thermally cured at 155 °C for 60 min.

[0081] b) Slice and measure the total thickness error between the copper surface and the substrate surface, and the results are shown in Table 1 below.

[0082] Table 1

[0083] Reflectivity Flatness Example 1 95％ 1.5μm Example 2 96％ 0.9μm Example 3 96％ 0.5μm

[0084] 3. Acid resistance test: 10% sulfuric acid, soak for 10 min. If there is no abnormality, it is qualified; otherwise, it is unqualified. The results are shown in Table 2 below.

[0085] 4. Alkali resistance test: 10% sodium hydroxide, soak for 10 min. If there is no abnormality, it is qualified; otherwise, it is unqualified. The results are shown in Table 2 below.

[0086] 5. Immersion Gold Solution Treatment Test: 3M Tape Test. If there is no peeling off, it is qualified; otherwise, it is unqualified.

[0087] Table 2

[0088] Acid resistance test Alkali resistance test Immersion gold solution treatment test Example 1 Qualified Qualified Qualified Example 2 Qualified Qualified Qualified Example 3 Qualified Qualified Qualified Example 4 Unqualified Unqualified Unqualified Example 5 Unqualified Unqualified Unqualified Example 6 Unqualified Unqualified Unqualified

Claims

1. A solder mask dry film resistant to chemical reagents, characterized in that by weight, the preparation raw materials include: 15-20 parts of modified acrylic resin A, 15-30 parts of modified acrylic resin B, 10-20 parts of acrylic monomers, 1-5 parts of organosiloxane, 1-5 parts of photoinitiator, 5-15 parts of curing agent, 50-400 parts of titanium dioxide, 10-30 parts of solvent, 1-10 parts of additives; The modified acrylic resin A is neopentyl glycol diacrylate, with an average molecular weight of 5000-10000; The modified acrylic resin B is bisphenol A epoxy acrylate; The acrylic monomer is α-furanacrylic acid.

2. The solder mask dry film according to claim 1, characterized in that the curing agent is one or a combination of aliphatic amine curing agents, amidoamine curing agents, aromatic curing agents, dicyandiamide curing agents, isocyanate curing agents.

3. The solder mask dry film according to claim 1, characterized in that the organosiloxane is selected from phenylmethyltrimethylpolysiloxane, 1,3-bis(3-methacryloxypropyl)tetramethyldisiloxane, 1,3-dibenzyltetramethyldisiloxane, polydimethylsiloxane, vinyltrimethoxysilane, propenyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxytrimethoxysilane, γ-methacryloxytrimethoxysilane, or a combination of one or more of them.

4. The solder mask dry film according to claim 1, characterized in that the titanium dioxide is rutile titanium dioxide.

5. The solder mask dry film according to claim 1, characterized in that the addition amount of the rutile titanium dioxide accounts for 50%-80% of the total mass of the raw material components.

6. The solder mask dry film according to claim 1, characterized in that the additives include one or a combination of antioxidants, plasticizers, tackifiers, dispersants, polymerization inhibitors.

7. A preparation method of the solder mask dry film according to any one of claims 1-6, characterized in that after mixing and stirring the preparation raw materials of the solder mask dry film, coating and hardening on a substrate material, the solder mask dry film is obtained.