Alkali-soluble polyurethane acrylate resins, their preparation methods and applications

Abstract

This invention discloses an alkali-soluble polyurethane acrylate resin, which is prepared from the following raw materials in parts by weight: 10-90 parts of hydroxyl-containing acrylate monomers, 1-10 parts of a first catalyst, 1-10 parts of a polymerization inhibitor, 130-160 parts of monoisocyanate monomers, 60-80 parts of acrylate monomers, 70-130 parts of acrylate monomers, 10-50 parts of a silane coupling agent, 1-10 parts of an initiator, 0.5-1 part of a chain transfer agent, 70-80 parts of a double-bonded epoxy monomer, 1-10 parts of a second catalyst, 30-50 parts of a double-bonded isocyanate monomer, and 300-500 parts of an organic solvent; the first catalyst is selected from at least one of organotin catalysts and tertiary amine catalysts, and the second catalyst is selected from at least one of tertiary amine catalysts and quaternary ammonium catalysts. The alkali-soluble polyurethane acrylate resin has silicon-oxygen bonds and carbon-carbon double bonds on its side chains, which can improve the resin's adhesion, acid and alkali resistance, photocuring ability, and developing ability. The solid content of the resin can be measured to be 57.3%. This invention also discloses the alkali-soluble polyurethane acrylate resin and its applications.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to alkali-soluble polyurethane acrylate resin, its preparation method, and its application. Background Technology

[0002] Photosensitive solder resist ink is a functional ink used in printed circuit boards. It cures under light of a specific wavelength, forming a protective film that protects the circuit board traces and prevents solder flow. Photosensitive solder resist ink plays a crucial role in the manufacture of IC substrates, forming a fine protective layer to prevent copper traces from being damaged by etching solutions, thus ensuring circuit integrity and improving the reliability and lifespan of the IC substrate. The high-resolution characteristics of photosensitive solder resist ink meet the precision manufacturing requirements of Mini-LEDs and are indispensable in their production.

[0003] Alkali-soluble polyurethane acrylate resin is one of the most commonly used photosensitive resins in the field of photosensitive solder resist inks. It has been widely used in many fields due to its excellent coating performance, controllable alkaline washing and developing ability, and rapid photocuring. However, with the rapid development of the modern electronics industry, people have increasingly higher requirements for the high temperature resistance, insulation performance, and etching resistance of photosensitive solder resist ink materials in IC substrates and Mini-LEDs. Therefore, it is necessary to improve the performance of alkali-soluble polyurethane acrylate resin based on these requirements. Summary of the Invention

[0004] The first objective of this invention is to provide an alkali-soluble polyurethane acrylate resin to solve at least one of the above-mentioned technical problems.

[0005] A second objective of the present invention is to provide a method for preparing alkali-soluble polyurethane acrylate resin, thereby solving at least one of the above-mentioned technical problems.

[0006] A third object of the present invention is to provide the application of alkali-soluble polyurethane acrylate resins to solve at least one of the above-mentioned technical problems.

[0007] A fourth objective of the present invention is to provide a photosensitive solder resist ink to solve at least one of the above-mentioned technical problems.

[0008] A fifth objective of the present invention is to provide a method for preparing photosensitive solder resist ink, thereby solving at least one of the above-mentioned technical problems.

[0009] A sixth objective of the present invention is to provide the application of photosensitive white solder resist ink in the preparation of Mini-LED or IC substrates, so as to solve at least one of the above-mentioned technical problems.

[0010] In a first aspect, the present invention provides an alkali-soluble polyurethane acrylate resin, prepared from the following raw materials in parts by weight:

[0011] The catalyst comprises 10-90 parts of hydroxyl-containing acrylate monomers, 1-10 parts of a first catalyst, 1-10 parts of a polymerization inhibitor, 130-160 parts of monoisocyanate monomers, 60-80 parts of acrylate monomers, 70-130 parts of acrylate monomers, 10-50 parts of a silane coupling agent, 1-10 parts of an initiator, 0.5-1 part of a chain transfer agent, 70-80 parts of double-bonded epoxy monomers, 1-10 parts of a second catalyst, 30-50 parts of double-bonded isocyanate monomers, and 300-500 parts of an organic solvent; the first catalyst is selected from at least one of organotin catalysts and tertiary amine catalysts, and the second catalyst is selected from at least one of tertiary amine catalysts and quaternary ammonium catalysts.

[0012] The alkali-soluble polyurethane acrylate resin of the present invention is prepared from a variety of raw materials. A chain transfer agent is used to control the molecular weight and degree of polymerization of the resin, resulting in a degree of polymerization of 10 for each unit. 4 -10 6 The organic solvent not only serves as a solvent for free radical polymerization but also adjusts the solid content and viscosity of alkali-soluble polyurethane acrylate resins. The alkali-soluble polyurethane acrylate resins prepared from the raw materials have silicon-oxygen bonds and unsaturated carbon-carbon double bonds on their side chains. The silicon-oxygen bonds improve the resin's adhesion and acid / alkali resistance, while the carbon-carbon double bonds promote photocuring and regulate the resin's developability by controlling its acid value. Solid content testing revealed that the solid content of the alkali-soluble polyurethane acrylate resin can reach 57.3%.

[0013] In some embodiments, the structural formula of the alkali-soluble polyurethane acrylate resin is shown in formula (I):

[0014]

[0015] In formula (I), the structural formula of PU is: R1 is a C1-C5 straight-chain or branched alkylene group; R2 is a C3-C8 cycloalkyl, phenyl, or C1-C4 alkyl-substituted phenyl group; R3 is a C1-C5 alkylene group. 18 The following are the possible meanings of the terms: R4 is a straight-chain or branched alkyl group, C1-C4 alkyl-substituted phenyl group; R5 is a C1-C5 straight-chain or branched alkylene group; R6 is a C1-C3 straight-chain or branched alkyl group; R7 is a C1-C3 straight-chain or branched alkylene group, ether bond, C1-C3 alkyl ether; R8 is a C1-C3 straight-chain or branched alkyl group; the degree of polymerization of x, y, z, and w is 10. 4 ~10 6 .

[0016] In other embodiments, R1 is a C1-C4 straight-chain or branched alkylene group, R2 is a C6-C8 cycloalkyl, phenyl, or C1-C2 alkyl-substituted phenyl group, and R3 is a C1-C4 alkylene group. 18 R4 is H or methyl; R6 is a C1-C2 alkyl group; R5 is a C1-C3 straight-chain or branched alkylene group; R6 is methyl or ethyl; R7 is a C1-C2 alkylene group, ether bond, or C1-C2 alkyl ether; R8 is a C1-C2 alkyl group.

[0017] In some embodiments, the hydroxyl-containing acrylate monomer may be selected from at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxypropyl acrylate, and hydroxybutyl acrylate.

[0018] In some embodiments, the organotin catalyst in the first catalyst may be selected from at least one of dibutyltin dilaurate (DBTDL) and dioctyltin dilaurate, and the tertiary amine catalyst may be selected from at least one of triethylenediamine and triethylenetetramine.

[0019] In some embodiments, the polymerization inhibitor may be selected from at least one of p-hydroxyanisole, hydroquinone, resorcinol, 2,6-di-tert-butyl-p-cresol, and tert-butylcatechol.

[0020] In some embodiments, the monoisocyanate monomer may be selected from at least one of phenyl isocyanate (PI), p-toluene isocyanate (MPI), and cyclohexyl isocyanate (CHI).

[0021] In some embodiments, the acrylate monomer may be selected from at least one of methyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, benzyl methacrylate, and octadecyl methacrylate.

[0022] In some embodiments, the acrylic monomer may be selected from at least one of methacrylic acid and acrylic acid.

[0023] In some embodiments, the silane coupling agent may be selected from at least one of vinyltrimethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane, and vinyltriethoxysilane.

[0024] In some embodiments, the initiator may be selected from at least one of azobisisobutyronitrile, benzoyl peroxide, tert-butyl peroxide, dimethyl azobisisobutyronitrile, tert-butyl peroxyvalerate, and azobisisoheptanenitrile.

[0025] In some embodiments, the amount of initiator is 4%-8% of the total mass of monomers (i.e., the total mass of polyurethane acrylate monomers, acrylate monomers, acrylic acid and silane coupling agent).

[0026] In some embodiments, the chain transfer agent may be selected from at least one of dodecyl mercaptan, octadecyl mercaptan, dithioester, and 2,4-diphenyl-4-methyl-1-pentene.

[0027] In some embodiments, the amount of chain transfer agent can be 1%-3% of the total mass of monomers (i.e., the total mass of polyurethane acrylate monomers, acrylate monomers, acrylic acid and silane coupling agent).

[0028] In some embodiments, the epoxy monomer containing the double bond may be selected from at least one of glycidyl methacrylate, 2-methyl-2-vinylethylene oxide, and 1,2-epoxy-4-vinylcyclohexane.

[0029] In some embodiments, the second catalyst may be selected from at least one of triethylenediamine (TEDA), triethylamine (TEA), N,N-dimethylaniline, and triethylenetetramine, and the quaternary ammonium catalyst may be selected from at least one of tetraethyl quaternary ammonium, tetrabutylammonium bromide, and tetrabutyl quaternary ammonium.

[0030] In some embodiments, the isocyanate monomer containing a double bond may be selected from at least one of vinyl isocyanate, propylene isocyanate, 1-isocyanatobutene-4, methyl methacrylate isocyanate, vinyl ethyl isocyanate, and ethyl 2-isocyanate.

[0031] In some embodiments, the organic solvent may be selected from at least one of divalent ester (DBE), dipropylene glycol methyl ether, butyl acetate, ethyl acetate, cyclohexanone, and tetramethylbenzene.

[0032] In some embodiments, the organic solvent may be 40%-50% of the total mass of the raw materials.

[0033] A second aspect of the present invention provides a method for preparing an alkali-soluble polyurethane acrylate resin, comprising the following steps:

[0034] S1. Mix monoisocyanate monomers, the first catalyst and the polymerization inhibitor, add hydroxyl-containing acrylate monomers dropwise at a temperature of 40-50℃ and react for 1-3 hours, then raise the temperature to 55-60℃ and react for 2-4 hours to obtain polyurethane acrylate monomers.

[0035] S2. Heat the organic solvent to 90-110℃, add the mixture dropwise to the organic solvent and react for 7-10 hours to obtain a polyurethane acrylate copolymer containing silicon-oxygen bonds.

[0036] S3. Add a polymerization inhibitor and an epoxy monomer containing double bonds to the polyurethane acrylate copolymer containing silicon-oxygen bonds at 70-80℃. After stirring for 15-20 minutes, add a second catalyst, raise the temperature to 90-100℃, and react until the acid value is 44-66 mg (KOH) / g or the epoxy equivalent is ≥25000 to obtain the polyurethane acrylate copolymer containing double bonds.

[0037] S4. Add a monomer containing a double bond, a polymerization inhibitor, and a first catalyst to the polyurethane acrylate copolymer containing a double bond at 40-60℃, and react until the NCO value is 0-2% to obtain the product.

[0038] The mixture consists of an initiator, a chain transfer agent, a silane coupling agent, polyurethane acrylate monomers, acrylate monomers, and acrylic monomers.

[0039] The method for preparing the alkali-soluble polyurethane acrylate resin of the present invention first obtains polyurethane acrylate monomers through a nucleophilic addition reaction of a monoisocyanate monomer with a hydroxyl-containing acrylate monomer. Then, free radicals are generated by an initiator, initiating the polymerization of polyurethane acrylate monomers containing carbon-carbon double bonds, acrylate monomers, acrylic monomers, and a silane coupling agent to form a copolymer. Carboxyl groups and siloxane bonds are introduced into the side chains, and the molecular weight and degree of polymerization of the copolymer are controlled by adding a chain transfer agent, thereby obtaining a copolymer with a degree of polymerization of 10 for each unit. 4 -10 6 The copolymer is first prepared by adding an epoxy monomer containing double bonds, which then undergoes a ring-opening reaction with the carboxyl hydroxyl groups on the copolymer side chains, introducing carbon-carbon double bonds and hydroxyl groups into the copolymer. Finally, an isocyanate monomer containing double bonds is added, which reacts with the hydroxyl groups on the copolymer side chains via a nucleophilic addition reaction to obtain an alkali-soluble polyurethane acrylate resin. This preparation method introduces silicon-oxygen bonds and carbon-carbon double bonds into the side chains of the alkali-soluble polyurethane acrylate resin, which can improve the resin's adhesion, acid and alkali resistance, photocuring performance, and developability.

[0040] In some embodiments, the first mixture is added over a period of 2.5-4 hours.

[0041] In some embodiments, by weight, in step S1, the amount of the first catalyst is 0.2-0.5 parts and the amount of the polymerization inhibitor is 0.2-0.5 parts; in step S3, the amount of the polymerization inhibitor is 1.5-6.5 parts; in step S4, the amount of the first catalyst is 0.6-3 parts and the amount of the polymerization inhibitor is 0.6-3 parts.

[0042] A third aspect of the present invention provides the use of alkali-soluble polyurethane acrylate resins in the preparation of photosensitive white solder resist inks.

[0043] A fourth aspect of the present invention provides a photosensitive white solder resist ink, comprising the following raw materials in weight percentages: 40%-60% alkali-soluble polyurethane acrylate resin, 1%-5% photoinitiator, 0.5%-5% pigment, 10%-40% filler, 10%-30% reactive diluent, 0.2%-1% dispersant, 0.3%-1% defoamer, 0.5%-1% leveling agent, and 0.4%-2% rheology modifier.

[0044] The photosensitive white solder resist ink of the present invention is prepared from alkali-soluble polyurethane acrylate resin. It performs well in multiple performance tests such as photosensitivity, reflectivity, yellowing resistance, acid and alkali resistance, high temperature resistance and etching resistance. It can not only cure quickly, but also resist acid and alkali in high temperature environment and can be used for a long time.

[0045] In some embodiments, the photoinitiator may be selected from 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-2-(4-morpholino)-1-[4-(methylthio)phenyl]-1-propanone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, and 2-dimethylamino-2-benzyl-1-[4-(4-morpholino] At least one of the following: phenyl-1-butanone, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone, methyl benzoylcarbamate, diphenyl ethyl ketone, α,α-dimethoxy-α-phenylacetophenone, α,α-diethoxyacetophenone, α-hydroxyalkyl phenyl ketone, α-aminealkyl phenyl ketone, benzophenone, 2,4-dihydroxybenzophenone, michidone, thiopropoxythionone, and isopropylthionone.

[0046] In some implementations, the pigment is titanium dioxide.

[0047] In some embodiments, the filler may be selected from at least one of kaolin, mica powder, calcium carbonate, talc powder, barium sulfate, silica powder, and quartz powder.

[0048] In some embodiments, the reactive diluent may be selected from at least one of trimethylolpropane triglycidyl ether, toluene glycidyl ether, neodecanoic acid glycidyl ester, castor oil polyglycidyl ether, adipate diacrylate, propylene glycol monomethyl ether acrylate, 2-ethoxyethyl acrylate, 2-phenoxyethyl acrylate, isobornyl acrylate, isobornyl methacrylate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate ethoxyethoxyethyl acrylate, dipropylene glycol diacrylate, neopentyl glycol diacrylate, and ethoxylated trimethylolpropane triacrylate.

[0049] In some embodiments, the dispersant may be selected from at least one of polymeric dispersants, polyether-modified silicone dispersants, and polycarboxylic acid polyester-polysiloxane copolymer dispersants.

[0050] In some embodiments, the dispersant may be selected from at least one of TEGO-685, TEGO-688, and BYK-220S. TEGO-685 is primarily a polymer, TEGO-688 is primarily a modified polyether, and BYK-220S is an unsaturated acidic polycarboxylic acid polyester solution containing a polysiloxane copolymer.

[0051] In some embodiments, the defoamer may be selected from at least one of silicone defoamers and alcohol defoamers.

[0052] In some embodiments, the defoamer may be selected from at least one of the commercially available products of System Technology, namely XST-5130, XST-5009, XST-4530, Z-201, and XST-5030Y. Specifically, XST-5130 is a silicone polyether defoamer, XST-5009 is a silicone polyether defoamer, XST-4530 is a fatty alcohol defoamer, Z-201 is an organosilicon defoamer, and XST-5030Y is a fatty alcohol defoamer.

[0053] In some implementations, the leveling agent is a silicone leveling agent.

[0054] In some embodiments, the leveling agent may be selected from at least one of BYK-333, BYK-300, BYK-326, and TEGO-432. Specifically, BYK-333's main component is polyether-modified polydimethylsiloxane, BYK-300 is a polyether-modified polydimethylsiloxane solution, BYK-326 is a polyether-modified polymethylalkylsiloxane solution, and TEGO-432's main component is a polyether siloxane copolymer.

[0055] In some embodiments, the rheology modifier may be selected from at least one of modified urea, urea-modified nonpolar polyamide, and urea-modified polyurethane.

[0056] In some embodiments, the rheology modifier may be selected from at least one of BYK-431, BYK-425, and BYK-410. Specifically, BYK-431 is a urea-modified nonpolar polyamide solution, BYK-425 is a urea-modified polyurethane solution, and BYK-410 is a polymer solution containing urea / urethane functional groups.

[0057] A fifth aspect of the present invention provides a method for preparing photosensitive white solder resist ink, comprising the following steps:

[0058] Mix alkali-soluble polyurethane acrylate resin, photoinitiator, pigment, filler and dispersant, disperse at 500-1000 rpm for 20-40 minutes, grind, add reactive diluent, leveling agent, defoamer and rheology modifier, disperse again at 500-800 rpm for 20-40 minutes, filter, and the product is obtained.

[0059] The photosensitive white solder resist ink of the present invention is prepared by adding alkali-soluble polyurethane acrylate resin, thereby obtaining a white solder resist ink that performs well in multiple performance tests such as photosensitivity, reflectivity, yellowing resistance, acid and alkali resistance, high temperature resistance and etching resistance.

[0060] A sixth aspect of the present invention provides the application of photosensitive white solder resist ink in the fabrication of Mini-LED or IC substrates. Specifically, the photosensitive solder resist ink can be applied to the IC substrate to form an insulating protective layer, preventing copper wires from being damaged by etching solution. The photosensitive solder resist ink can also be applied to areas of the circuit board other than those where Mini-LED chips and other electronic components need to be soldered, forming an insulating protective layer. Attached Figure Description

[0061] Figure 1 This is a synthesis route diagram according to one embodiment of the present invention. Detailed Implementation

[0062] The present invention will now be described in further detail with reference to the accompanying drawings, but the embodiments of the present invention are not limited thereto. The raw materials and reagents involved in the following embodiments are all commercially available.

[0063] The synthetic route of the alkali-soluble polyurethane acrylate resin of the present invention is as follows ( Figure 1 Taking (e.g.) as an example, the synthetic route of the present invention will be described in detail:

[0064] ①The isocyanate group of monoisocyanate monomers and the hydroxyl group of hydroxyl-containing acrylate monomers undergo a nucleophilic addition reaction under the action of a first catalyst and a polymerization inhibitor to obtain polyurethane acrylate monomers containing double bonds.

[0065] ② The double bonds of polyurethane acrylate monomers, acrylate monomers, silane coupling agents and acrylate monomers undergo free radical polymerization under the action of an initiator, and the molecular weight of the copolymer is controlled by a chain transfer agent to obtain a polyurethane acrylate copolymer containing silicon-oxygen bonds.

[0066] ③The carboxyl hydroxyl groups on the side chains of the polyurethane acrylate copolymer containing silicon-oxygen bonds react with the epoxy groups of the epoxy monomer containing double bonds in the ring-opening reaction under the action of a second catalyst and a polymerization inhibitor to obtain the polyurethane acrylate copolymer containing double bonds.

[0067] ④ The hydroxyl groups on the side chains of the polyurethane acrylate copolymer containing double bonds undergo an addition reaction with the isocyanate groups on the isocyanate monomer containing double bonds under the action of the first catalyst and the polymerization inhibitor, thereby introducing the isocyanate monomer containing double bonds into the side chains of the polyurethane acrylate copolymer containing double bonds, and obtaining alkali-soluble polyurethane acrylate resin.

[0068] Figure 1 In this context, R1 is a C1-C5 straight-chain or branched alkylene group, R2 is a C3-C8 cycloalkyl, phenyl, or C1-C4 alkyl-substituted phenyl group, and R3 is a C1-C5 alkylene group. 18 The following are the possible meanings of the terms: R4 is a straight-chain or branched alkyl group, C1-C4 alkyl-substituted phenyl group; R5 is a C1-C5 straight-chain or branched alkylene group; R6 is a C1-C3 straight-chain or branched alkyl group; R7 is a C1-C3 straight-chain or branched alkylene group, ether bond, C1-C3 alkyl ether; R8 is a C1-C3 straight-chain or branched alkyl group; the degree of polymerization of x, y, z, and w is 10. 4 ~10 6 .

[0069] The test methods for acid value, epoxy equivalent, and isocyanate group content (NCO value) of this invention are described in detail below:

[0070] (1) Acid value test

[0071] The determination is performed using a standard potassium hydroxide solution. The principle is that potassium hydroxide reacts with the remaining carboxyl group (-COOH), and the equation is KOH + RCOOH → H2O + RCOOK.

[0072] The specific steps are as follows: Place 0.25-0.5 g of sample into a 100 mL beaker and weigh accurately to 0.001 g. Add 20-40 mL of acetone and stir with a glass rod until completely dissolved. After dissolving, add 2-3 drops of 2% cresol red indicator and continue stirring until homogeneous. Then, titrate with 0.2 mol / L potassium hydroxide standard solution until the color of the mixture changes from yellow to purple-red, and record the volume consumed (mL).

[0073] The formula for calculating acid value (mg(KOH) / g) is: acid value = V×C(KOH)×56.1 / G, where V is the volume of potassium hydroxide consumed (mL); C is the concentration of potassium hydroxide standard solution (mol / L); and G is the weight of the sample (g).

[0074] (2) Epoxy Equivalent Test

[0075] The test was conducted according to the test method of the national standard GB / T 4612-2008 "Determination of Epoxy Equivalent in Plastic Epoxy Compounds".

[0076] (3) Isocyanate group content test

[0077] The principle is that the isocyanate group reacts with excess di-n-butylamine to form urea, and then the remaining di-n-butylamine is titrated with hydrochloric acid to determine the content of isocyanate group. The reaction equations are R-NCO + (C4H9)2NH → RNHCON(C4H9)2; (C4H9)2NH + HCl → (C4H9)2NH·HCl.

[0078] The procedure is as follows: First, prepare a standard solution of bromocresol green indicator and a 0.1 mol / L di-n-butylamine-toluene solution. Then, accurately weigh 1.0000 g of the sample and place it in a dry conical flask. Add 25 mL of toluene to dissolve the sample, and then accurately add 25.00 mL of the di-n-butylamine-toluene solution. Seal the flask, shake thoroughly, and let it stand for 15 minutes. Next, add 100 mL of isopropanol and 5 drops of bromocresol green indicator, and titrate with 0.1 mol / L HCl standard solution until the color changes from blue to yellow. Perform a blank experiment simultaneously.

[0079] The formula for calculating the isocyanate group content is: W(NCO) / %=(V0-V)×c×4.202 / m, where V0 is the volume of HCl standard solution consumed in the blank (mL); V is the volume of HCl standard solution consumed in the sample (mL); c is the concentration of HCl standard solution (mol / L); and m is the mass of the sample (g).

[0080] The method for preparing a standard solution of bromocresol green indicator is as follows: dissolve 0.1 g in 100 mL of 20% ethanol solution. The method for preparing a standard solution of bromocresol green indicator is as follows: dissolve 12.9 g of di-n-butylamine in 100-200 mL of toluene, and then dilute to 1000 mL with deionized water.

[0081] Example 1

[0082] This embodiment provides an alkali-soluble polyurethane acrylate resin, the preparation method of which includes the following steps:

[0083] (1) Add 156.76g of phenyl isocyanate and 0.32g of triethylenediamine to a 1000mL four-necked round-bottom flask equipped with a thermometer, reflux condenser and stirrer, then add 0.32g of p-hydroxyanisole, add 82.31g of hydroxyethyl acrylate dropwise at 40-50℃ and react for 1h, then raise the temperature to 55℃ and react for 2h to obtain polyurethane acrylate monomer; the weight of polyurethane acrylate monomer is 70g;

[0084] (2) Add 300 mL of dipropylene glycol methyl ether to a 1000 mL four-necked round-bottom flask equipped with a thermometer, a straight condenser, a constant pressure dropping funnel and a stirrer, heat to 90 °C, and then add dropwise a first mixture containing 2.3 g benzoyl peroxide, 0.8 g dodecyl mercaptan, 10.34 g vinyltrimethoxysilane, the polyurethane acrylate monomer prepared in step (1), 120 g methacrylic acid and 75 g methyl methacrylate. After the first mixture is added dropwise in 2.5 h, react at 90 °C for 7 h to obtain a polyurethane acrylate copolymer containing silicon-oxygen bonds.

[0085] (3) Cool down to 70°C, add 75g of 2-methyl-2-vinyl ethylene oxide and 2g of polymerization inhibitor 2,6-di-tert-butyl-p-cresol to the polyurethane acrylate copolymer containing silicon-oxygen bonds, stir for 15 minutes, add 2g of tetrabutyl quaternary ammonium, and slowly raise the temperature to 90°C for 1 hour to carry out the reaction. Stop the reaction when the acid value reaches 46-66mg(KOH) / g or the epoxy equivalent is ≥25000.

[0086] (4) Cool down to 40°C, add 43.21g vinyl isocyanate, 1.2g p-hydroxyanisole and 1.2g triethylenediamine and react until the NCO value of the system is 0-2% to obtain alkali-soluble polyurethane acrylate resin.

[0087] Example 2

[0088] This embodiment provides an alkali-soluble polyurethane acrylate resin, the preparation method of which includes the following steps:

[0089] (1) 147.34 g of p-toluene isocyanate and 0.45 g of dibutyltin dilaurate were added to a 1000 mL four-necked round-bottom flask equipped with a thermometer, reflux condenser and stirrer. Then 0.45 g of tert-butylcatechol was added. After adding 85.71 g of hydroxyethyl methacrylate dropwise at 50 °C for 3 h, the temperature was raised to 60 °C and the reaction was carried out for 4 h to obtain polyurethane acrylate monomer. The weight of polyurethane acrylate monomer was 75 g.

[0090] (2) Add 300 mL of divalent ester to a 1000 mL four-necked round-bottom flask equipped with a thermometer, a straight condenser, a constant pressure dropping funnel and a stirrer, heat to 110 °C, and then add dropwise a first mixture containing 2.4 g azobisisobutyronitrile, 0.9 g octadecyl mercaptan, 12.44 g methacryloyloxypropyltrimethoxysilane, the polyurethane acrylate monomer prepared in step (1), 133.15 g acrylic acid and 65.46 g cyclohexyl methacrylate. After the first mixture is added dropwise over 4 h, react at 90-110 °C for 10 h to obtain a polyurethane acrylate copolymer containing silicon-oxygen bonds.

[0091] (3) Cool down to 80℃, add 75g of 2-methyl-2-vinyl ethylene oxide and 2g of polymerization inhibitor 2,6-di-tert-butyl-p-cresol to the polyurethane acrylate copolymer containing silicon-oxygen bonds, stir for 20 minutes, add 2g of tetrabutyl quaternary ammonium, slowly heat up to 100℃ for 1 hour and carry out the reaction. Stop the reaction when the acid value reaches 46-66mgKOH / g or the epoxy equivalent is ≥25000 to obtain the polyurethane acrylate copolymer containing double bonds;

[0092] (4) Cool down to 60℃, add 40.21g vinyl isocyanate, 1.3g p-hydroxyanisole and 1.3g triethylenediamine and then react. Stop the reaction when the NCO value of the system is 0-2% to obtain alkali-soluble polyurethane acrylate resin.

[0093] Example 3

[0094] This embodiment provides a photosensitive white solder resist ink, the formulation of which is shown in Table 1.

[0095] Table 1. Formulation composition of photosensitive white solder resist ink

[0096]

[0097] The preparation method includes the following steps:

[0098] The alkali-soluble polyurethane acrylate resin, photoinitiator, pigment, filler, and dispersant prepared in Example 1 were added to a dispersion tank according to the formulation. Then, the mixture was dispersed for 30 minutes at 500 rpm using a high-speed disperser, followed by grinding with a three-roll mill until the fineness of the material was less than 25 micrometers. Subsequently, an active diluent, leveling agent, defoamer, and rheology modifier were added to the ground material, and the mixture was dispersed again for 30 minutes at 500 rpm using a high-speed disperser. The mixture was then filtered to obtain the final product.

[0099] Example 4

[0100] This embodiment provides a photosensitive white solder resist ink, the formulation of which is shown in Table 2.

[0101] Table 2 Formulation of Photosensitive White Solder Resist Ink

[0102]

[0103]

[0104] The photosensitive white solder resist ink of this embodiment is prepared by the following steps:

[0105] According to the formulation in Table 2, the alkali-soluble polyurethane acrylate resin, photoinitiator, pigment, filler, and dispersant prepared in Example 2 were added to a dispersion tank. Then, the mixture was dispersed for 30 minutes at 1000 rpm using a high-speed disperser, followed by grinding with a three-roll mill until the material fineness was less than 25 micrometers. Subsequently, an active diluent, leveling agent, defoamer, and rheology modifier were added to the ground material, and it was dispersed again for 30 minutes at 800 rpm using a high-speed disperser. The mixture was then filtered to obtain the final product.

[0106] Experimental Example 1

[0107] This experimental example calculates the solid content of the alkali-soluble polyurethane acrylate resins prepared in Examples 1 and 2, respectively.

[0108] The total mass of the silane coupling agent, polyurethane acrylate monomer, acrylate monomer, acrylic monomer, epoxy monomer containing double bonds, isocyanate monomer containing double bonds, polymerization inhibitor, initiator, chain transfer agent, first catalyst, and second catalyst added in steps (2)-(4) is recorded as the solid content. The total amount of the solid content is recorded as the sum of the mass of the silane coupling agent, polyurethane acrylate monomer, acrylate monomer, acrylic monomer, epoxy monomer containing double bonds, isocyanate monomer containing double bonds, polymerization inhibitor, initiator, chain transfer agent, first catalyst, and second catalyst added in steps (2)-(4) and the solvent volume of the organic solvent. The solvent volume of the organic solvent is the volume of the organic solvent added in step (2). The solid content is calculated by the following formula:

[0109]

[0110] In Example 1, the amount of dipropylene glycol methyl ether, an organic solvent, was 300 mL. Based on calculations, the total amount was 703.05 g. Therefore, the solid content of the alkali-soluble polyurethane acrylate resin prepared in Example 1 was...

[0111] In Example 2, the organic solvent, divalent ester, was used in a volume of 300 mL. Based on calculations, the total volume was 711.16 g. Therefore, the solid content of the alkali-soluble polyurethane acrylate resin prepared in Example 2 was...

[0112] Experiment Example 2

[0113] This experiment tests the performance of the photosensitive white solder resist inks prepared in Examples 3 and 4.

[0114] The photosensitive white solder resist inks of Examples 3 and 4 were printed on copper-clad laminates and baked at 75°C for 30-45 minutes to obtain samples.

[0115] I. Photosensitivity

[0116] A 21-level optical gradient ruler was placed above the film layer of the sample, and the sample was exposed and developed under an LED light source exposure machine. The time it took for 9 grids of film layer residue to remain was used as the standard.

[0117] II. Reflectivity

[0118] The sample was exposed and developed under an LED light source, then baked in an oven at 150°C for 1 hour. The reflectance of one of the copper-containing areas was then measured using a colorimeter.

[0119] III. Resistance to yellowing

[0120] The sample was exposed and developed under an LED light source exposure machine, and then baked in an oven at 150°C for 1 hour. Subsequently, one area of ​​the copper-clad laminate was immersed in a tin solution at 288°C for 10 seconds, and this was repeated three times. After each immersion, the same area was tested with a colorimeter to observe the change in the b value before and after. The difference between the b values ​​obtained from the first and third tests was recorded as Δb.

[0121] IV. Resistant to acids and alkalis

[0122] The sample was exposed and developed using an LED light source, then baked in a 150°C oven for 1 hour. It was then cut into small pieces and placed in 10% (wt%) sodium hydroxide solution and 10% (wt%) sulfuric acid solution for 30 minutes respectively. The pieces were then attached to the cut copper plates with 3M tape, and the tape was removed three times to observe the severity of ink peeling. No peeling was rated "Excellent," slight peeling "Good," and severe peeling "Poor."

[0123] V. High temperature resistance

[0124] The sample was exposed and developed under an LED light source, then baked in an oven at 150℃ for 1 hour. It was then cut into small pieces and immersed in a molten tin solution at 288℃ for 10 seconds each time, three times in total. After each immersion, the sample was taped to the copper-clad laminate and then peeled off. The presence of ink peeling was observed. No ink peeling was rated "Excellent," slight peeling was rated "Good," and severe peeling was rated "Poor."

[0125] VI. Etching resistance

[0126] The etching resistance was tested according to the test method of "GB / T 29846-2013 Photolithography Resist for Printed Circuit Boards". After etching, the pattern is complete, the line edges are neat, and there is no wrinkling, peeling or jagged shape. The pattern with wrinkles but no peeling is good, and peeling is poor.

[0127] The photosensitive white solder resist inks prepared in Examples 3 and 4 were tested for their photosensitivity, reflectivity, yellowing resistance, acid and alkali resistance, high temperature resistance, and etching resistance. The results are shown in Table 3.

[0128] Table 3. Performance Test Results of Photosensitive White Solder Resist Ink

[0129]

[0130] As shown in Table 3, the photosensitive white solder resist inks prepared in Examples 3 and 4 performed excellently in multiple performance tests. Specifically, in the photosensitivity test, the photosensitive white solder resist ink could complete curing after 11 seconds of exposure in an LED light source exposure machine; in the reflectivity test, the reflectivity of the photosensitive white solder resist ink could reach over 86.13%; in the yellowing resistance test, the optimal test result of Δb for the photosensitive white solder resist ink was 0.46. Meanwhile, the photosensitive white solder resist ink received "excellent" ratings in acid and alkali resistance and high temperature resistance tests, indicating that the white solder resist ink printed on the copper-clad laminate did not peel off from the copper-clad laminate after treatment with acids, alkalis, and a tin solution at 288°C. Furthermore, in the etching resistance test, after etching with 1 ounce of copper, the visually inspected pattern remained intact, the line edges were neat, and there were no wrinkles, peeling, or jagged edges; after etching with 2 ounces of copper, wrinkling did not occur or peeling occurred.

[0131] The performance test results show that the alkali-soluble polyurethane acrylate resin of this invention has silicon-oxygen bonds and carbon-carbon double bonds. The silicon-oxygen bonds improve the resin's adhesion and acid / alkali resistance, while the carbon-carbon double bonds promote photocuring and regulate the resin's development ability by controlling its acid value. The photosensitive white solder resist ink made from the alkali-soluble polyurethane acrylate resin performs well in multiple performance tests, including photosensitivity, reflectivity, yellowing resistance, acid and alkali resistance, high temperature resistance, and etching resistance, meeting the requirements of Mini-LEDs. When applied to the manufacture of Mini-LEDs, the photosensitive white solder resist ink of this invention not only cures rapidly, promoting the formation of high-precision patterns and structures, but also maintains the clarity and accuracy of the patterns during etching. Simultaneously, the high reflectivity and high yellowing resistance of the photosensitive white solder resist ink reduce the impact of light reflection on the ink. Furthermore, the photosensitive white solder resist ink is resistant to chemical corrosion in long-term high-temperature environments, preventing paint layer peeling due to high temperatures, further protecting the circuit and ensuring the long-term stable operation of Mini-LEDs.

[0132] The above descriptions are merely some embodiments of the present invention. Those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. An alkali-soluble polyurethane acrylate resin, characterized in that, It is prepared from the following raw materials in parts by weight: The composition comprises 10-90 parts of hydroxyl-containing acrylate monomers, 1-10 parts of a first catalyst, 1-10 parts of a polymerization inhibitor, 130-160 parts of monoisocyanate monomers, 60-80 parts of acrylate monomers, 70-130 parts of acrylate monomers, 10-50 parts of a silane coupling agent, 1-10 parts of an initiator, 0.5-1 part of a chain transfer agent, 70-80 parts of double-bonded epoxy monomers, 1-10 parts of a second catalyst, 30-50 parts of double-bonded isocyanate monomers, and 300-500 parts of an organic solvent; the first catalyst is selected from at least one of organotin catalysts and tertiary amine catalysts, and the second catalyst is selected from at least one of tertiary amine catalysts and quaternary ammonium catalysts. The silane coupling agent is selected from at least one of vinyltrimethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane, and vinyltriethoxysilane. The alkali-soluble polyurethane acrylate resin is prepared by the following steps: S1. Mix monoisocyanate monomers, the first catalyst and the polymerization inhibitor, add hydroxyl-containing acrylate monomers dropwise at a temperature of 40-50℃ and react for 1-3 hours, then raise the temperature to 55-60℃ and react for 2-4 hours to obtain polyurethane acrylate monomers. S2. Heat the organic solvent to 90-110℃, add the mixture dropwise to the organic solvent and react for 7-10 hours to obtain a polyurethane acrylate copolymer containing silicon-oxygen bonds. S3. Add a polymerization inhibitor and an epoxy monomer containing double bonds to the polyurethane acrylate copolymer containing silicon-oxygen bonds at 70-80℃. After stirring for 15-20 minutes, add a second catalyst, raise the temperature to 90-100℃, and react until the acid value is 46-66 mgKOH / g or the epoxy equivalent is ≥25000 to obtain the polyurethane acrylate copolymer containing double bonds. S4. At 40-60℃, add isocyanate monomers containing double bonds, polymerization inhibitors, and a first catalyst to the polyurethane acrylate copolymer containing double bonds, and react until the NCO value is 0%-2% to obtain the product. The mixture comprises an initiator, a chain transfer agent, a silane coupling agent, polyurethane acrylate monomers, acrylate monomers, and acrylic monomers. By weight, in step S1, the amount of the first catalyst is 0.2-0.5 parts, and the amount of the polymerization inhibitor is 0.2-0.5 parts; in step S3, the amount of the polymerization inhibitor is 1.5-6.5 parts; and in step S4, the amount of the first catalyst is 0.6-3 parts, and the amount of the polymerization inhibitor is 0.6-3 parts.

2. The alkali-soluble polyurethane acrylate resin according to claim 1, characterized in that, The hydroxyl-containing acrylate monomers are selected from at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxypropyl acrylate, and hydroxybutyl acrylate; the acrylate monomers are selected from at least one of methyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, benzyl methacrylate, and octadecyl methacrylate; the acrylic monomers are selected from at least one of methacrylic acid and acrylic acid; in the first catalyst, the organotin catalyst is selected from at least one of dibutyltin dilaurate and dioctyltin dilaurate, and the tertiary amine catalyst is selected from at least one of triethylenediamine and triethylenetetramine; the polymerization inhibitor is selected from at least one of p-hydroxyanisole, hydroquinone, resorcinol, 2,6-di-tert-butyl-p-cresol, and tert-butylcatechol; the monoisocyanate monomers are selected from at least one of phenyl isocyanate, p-toluene isocyanate, and cyclohexyl isocyanate; the initiator is selected from azobisisobutyronitrile, benzoyl peroxide, and tert-butyl peroxide. The catalyst comprises at least one of dimethyl azobisisobutyrate, tert-butyl peroxyvalerate, and azobisisoheptanenitrile; the chain transfer agent is selected from at least one of dodecanethiol, octadecylthiol, dithioester, and 2,4-diphenyl-4-methyl-1-pentene; the double-bonded epoxy monomer is selected from at least one of glycidyl methacrylate, 2-methyl-2-vinylethylene oxide, and 1,2-epoxy-4-vinylcyclohexane; in the second catalyst, the tertiary amine catalyst is selected from triethylenediamine, triethylamine, etc. The catalyst is selected from at least one of amine, N,N-dimethylaniline, and triethylenetetramine; the quaternary ammonium catalyst is selected from at least one of tetraethyl quaternary ammonium, tetrabutylammonium bromide, and tetrabutyl quaternary ammonium; the isocyanate monomer containing a double bond is selected from at least one of vinyl isocyanate, propylene isocyanate, methyl methacrylate isocyanate, vinyl ethyl isocyanate, and 2-isocyanoethyl acrylate; the organic solvent is selected from at least one of divalent ester, dipropylene glycol methyl ether, butyl acetate, ethyl acetate, cyclohexanone, and tetramethylbenzene.

3. The alkali-soluble polyurethane acrylate resin according to claim 1, characterized in that, The amount of the initiator is 4%-8% of the total mass of the polyurethane acrylate monomer, acrylate monomer, acrylic acid and silane coupling agent; the amount of the chain transfer agent is 1%-3% of the total mass of the polyurethane acrylate monomer, acrylate monomer, acrylic acid and silane coupling agent; and the mass of the organic solvent is 40%-50% of the total mass of the raw materials.

4. The method for preparing the alkali-soluble polyurethane acrylate resin according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Mix monoisocyanate monomers, the first catalyst and the polymerization inhibitor, add hydroxyl-containing acrylate monomers dropwise at a temperature of 40-50℃ and react for 1-3 hours, then raise the temperature to 55-60℃ and react for 2-4 hours to obtain polyurethane acrylate monomers. S2. Heat the organic solvent to 90-110℃, add the mixture dropwise to the organic solvent and react for 7-10 hours to obtain a polyurethane acrylate copolymer containing silicon-oxygen bonds. S3. Add a polymerization inhibitor and an epoxy monomer containing double bonds to the polyurethane acrylate copolymer containing silicon-oxygen bonds at 70-80℃. After stirring for 15-20 minutes, add a second catalyst, raise the temperature to 90-100℃, and react until the acid value is 46-66 mgKOH / g or the epoxy equivalent is ≥25000 to obtain the polyurethane acrylate copolymer containing double bonds. S4. At 40-60℃, add isocyanate monomers containing double bonds, polymerization inhibitors, and a first catalyst to the polyurethane acrylate copolymer containing double bonds, and react until the NCO value is 0%-2% to obtain the product. The mixture comprises an initiator, a chain transfer agent, a silane coupling agent, polyurethane acrylate monomers, acrylate monomers, and acrylic monomers. By weight, in step S1, the amount of the first catalyst is 0.2-0.5 parts, and the amount of the polymerization inhibitor is 0.2-0.5 parts; in step S3, the amount of the polymerization inhibitor is 1.5-6.5 parts; and in step S4, the amount of the first catalyst is 0.6-3 parts, and the amount of the polymerization inhibitor is 0.6-3 parts.

5. The use of the alkali-soluble polyurethane acrylate resin according to any one of claims 1-3 in the preparation of photosensitive white solder resist ink.

6. A photosensitive white solder resist ink, characterized in that, It is composed of the following raw materials by mass percentage: 40%-60% alkali-soluble polyurethane acrylate resin as described in any one of claims 1-3, 1%-5% photoinitiator, 0.5%-5% pigment, 10%-40% filler, 10%-30% reactive diluent, 0.2%-1% dispersant, 0.3%-1% defoamer, 0.5%-1% leveling agent, and 0.4%-2% rheology modifier.

7. The photosensitive white solder resist ink according to claim 6, characterized in that, The photoinitiator is selected from 1-hydroxycyclohexylphenyl ketone, 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2-hydroxy-2-methyl-1-[4-( At least one of the following: 2-hydroxyethoxyphenyl]-1-propanone, methyl benzoylcarbamate, diphenyl ethyl ketone, α,α-dimethoxy-α-phenylacetophenone, α,α-diethoxyacetophenone, α-hydroxyalkyl phenyl ketone, α-aminealkyl phenyl ketone, benzophenone, 2,4-dihydroxybenzophenone, michalcone, thiopropoxythioxanthanone, and isopropylthioxanthanone; the pigment is titanium dioxide; the filler is selected from kaolin, mica powder, and carbon. The active diluent is selected from at least one of the following: calcium phosphate, talc, barium sulfate, silica fume, and quartz powder; the active diluent is selected from at least one of the following: bisacrylic acid diacrylate, propylene glycol monomethyl ether acrylate, 2-ethoxyethyl acrylate, 2-phenoxyethyl acrylate, isobornyl acrylate, isobornyl methacrylate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, ethoxyethoxyethyl acrylate, dipropylene glycol diacrylate, neopentyl glycol diacrylate, and ethoxylated trimethylolpropane triacrylate; the dispersant is selected from polymeric dispersants; the defoamer is selected from at least one of silicone defoamers and alcohol defoamers; the leveling agent is a silicone leveling agent; and the rheology modifier is selected from at least one of modified urea, urea-modified neutral polyamide, and urea-modified urethane.

8. The method for preparing the photosensitive white solder resist ink according to claim 6 or 7, characterized in that, Includes the following steps: Mix the alkali-soluble polyurethane acrylate resin, photoinitiator, pigment, filler and dispersant, disperse at 500-1000 rpm for 20-40 minutes, grind, add reactive diluent, leveling agent, defoamer and rheology modifier, disperse again at 500-800 rpm for 20-40 minutes, filter to obtain the final product.

9. The use of the photosensitive white solder resist ink according to claim 6 or 7 in the preparation of Mini-LED or IC substrates.

Images