Multifunctional photo-curing monomer as well as preparation method and application thereof

Abstract

The invention discloses a multifunctional photocuring monomer and a preparation method thereof, and the structure of the multifunctional photocuring monomer takes polyethylene glycol as a core group and comprises a plurality of pyridine groups and UV crosslinking end groups. The photocuring monomer can be applied to a photocuring reaction system required by formula compositions such as coatings, printing ink and adhesives, the hydrophilicity, rigidity and crosslinking degree of the photocuring reaction system can be regulated and controlled by using the photocuring monomer, and the adhesive force, hardness and other properties of the formula compositions are effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of photocurable monomers for photoresists and relates to a preparation method of multifunctional photocurable monomers. Background Art

[0002] In recent years, photocuring technology has received more and more attention and research. Due to its green, environmentally friendly and safe advantages, it has been widely used in coatings, inks, electronic communications, photoresists, dental materials and 3D printing.

[0003] As one of the important components of the photocuring system, the photocuring monomer has a great influence on the curing rate and degree of curing of the photocuring material. The monomer is also called a reactive diluent, which can reduce the viscosity of the photocuring system and improve the solubility. The monomer also contains functional groups that participate in cross-linking and curing, which affects the curing rate of the photocuring system and the performance of the cured film. According to the different functionalities, monomers can also be divided into monofunctional, bifunctional and multifunctional monomers. Monofunctional monomers have low viscosity and strong dilution, but they are more volatile, have low photocuring rate, low crosslinking degree and low volume shrinkage; bifunctional monomers have low viscosity, strong dilution, and fast photocuring speed; multifunctional monomers have high curing speed, high crosslinking degree, good wear resistance and weather resistance, but high viscosity, increased shrinkage after curing, and are brittle. In order to achieve a good photocuring effect, different photocuring monomers are usually selected to improve the compatibility and sensitivity of different formula compositions. At present, photocuring monomers cannot effectively balance the performance of viscosity and curing speed, flexibility and rigidity, hydrophilicity and alkali resistance. Summary of the invention

[0004] The present invention proposes a multifunctional photocurable monomer, the structure of which is shown in formula (I): a linear structure with polyethylene glycol as a core group, pyridine as an intermediate group, and multiple double bonds as end groups, which increases the flexibility and hydrophilicity of the structure, and does not easily produce gaps in the film after photocuring, and the structure is more compact and flat. By using this multifunctional photocurable monomer in different formula compositions, the present invention can flexibly adjust the hydrophilicity, flexibility and crosslinking degree of the photocurable reaction system, and effectively improve the adhesion, hardness and other properties of the different formula compositions.

[0005]

[0006] in,

[0007] R 1 , R 2 , R 3 , R 4 It is one of the following groups, one end is an ester bond or an amide bond, the other end is a double bond, or an acrylate, and the middle segment is C 1 -C 4Straight or branched alkane, R 1 , R 2 , R 3 , R 4 They can be of the same structure or of different structures. 1 , R 2 , R 3 , R 4 One end connected to the benzene ring is an ester bond or an amide bond, and the terminal group is a double bond or an acrylate;

[0008] n is the degree of polymerization 1-8.

[0009] The present invention also provides a photocurable composition, comprising: (A) the multifunctional photocurable monomer as described above.

[0010] The weight of the multifunctional photocurable monomer accounts for 0.1-60% of the total solid content of the photocurable composition; preferably, 1-30%.

[0011] The total solid content of the present invention refers to the total weight of the solid content of the photocurable composition, excluding the weight of the solvent.

[0012] The photocurable composition of the present invention further comprises (B) a photopolymerizable compound and (C) a photoinitiator.

[0013] The component (B) photopolymerizable compound is a free radical polymerizable compound containing an ethylenically unsaturated group. The free radical polymerizable compound may be in the form of a monomer or a resin (including an oligomer and a prepolymer), or may be in the form of both a monomer and a resin; the weight of the photopolymerizable compound accounts for 10 to 90% of the total solid content of the photocurable composition.

[0014] The free radical polymerizable compound in monomer form includes free radical polymerizable monofunctional compounds, difunctional compounds, trifunctional or higher functional compounds and mixtures thereof, preferably a mixture of monofunctional compounds, difunctional compounds and trifunctional compounds or a mixture of two or more difunctional compounds; the weight of the free radical polymerizable compound in monomer form accounts for 10 to 80% of the total solid content of the photocurable composition.

[0015] Among them, free radical polymerizable monofunctional compounds have low viscosity and can be used as photoreactive diluents, including but not limited to: (meth)acrylate compounds, (meth)acryloyl compounds, ethylene derivatives, styrene compounds, anhydride compounds containing ethylenically unsaturated double bonds, N-vinyl pyrrolidone, N-vinyl formamide, etc.

[0016] Among them, the (meth)acrylate compounds include but are not limited to: (meth)acrylate C1-C18 alkyl esters, preferably (meth)acrylate C1-C6 alkyl esters, such as: methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, 2-isobutyl ethoxy phthalate, etc.;

[0017] Among them, hydroxyl-functionalized (meth)acrylate compounds include, but are not limited to: (meth)acrylate hydroxy C1-C6 alkyl esters, such as: (meth)acrylate 2-hydroxyethyl, (meth)acrylate hydroxypropyl, (meth)acrylate hydroxybutyl, methacrylate glycidyl, etc.;

[0018] Among them, the (meth)acrylate compounds having a cyclic skeleton include, but are not limited to: isobornyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, γ-butyrolactone (meth)acrylate, γ-butyrolactone (meth)acrylate, tricyclodecanol (meth)acrylate, etc.;

[0019] Among them, (meth)acrylate compounds containing alkoxy modifications such as EO and PO (such as having 1-10, such as 2, 4, 6 or 8, preferably 1-5 EO and / or PO units) include but are not limited to: methoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, phenoxyethyl (meth)acrylate, etc.

[0020] Among them, (meth)acryloyl compounds include but are not limited to: acryloyl morpholine, 2-methacryloyl ethoxysuccinate, N,N-dimethylacrylamide, N,N-diethylacrylamide and N,N-dipropylacrylamide.

[0021] Among them, ethylene derivatives include but are not limited to: vinyl esters, preferably vinyl esters of C2-C6 monocarboxylic acids, such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, vinyl hexanoate or mixtures thereof.

[0022] The styrene compounds include but are not limited to chloromethylstyrene and / or α-methylstyrene.

[0023] The anhydride compounds containing ethylenically unsaturated double bonds include, but are not limited to, maleic anhydride and the like.

[0024] As one embodiment of the present invention, the weight of the free radical polymerizable monofunctional compound is 0-80% based on the total solid content of the photocurable composition of the present invention, for example 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70% or 80%.

[0025] Among them, the reaction activity of the free radical polymerizable bifunctional compound is higher than that of the monofunctional compound, and the surface curing property of the ink can be improved. Its viscosity is lower than that of the free radical polymerizable trifunctional compound. By using it in combination with the monofunctional compound, it can be used as a diluent for trifunctional and more functional compounds, so that the viscosity of the photocurable composition and the photosensitive ink of the present invention is reduced and the reactivity is improved.

[0026] As free-radically polymerizable bifunctional compounds, for example di(meth)acrylates of diols or triols having 2 to 12, such as 2, 4, 6, 8 or 10, carbon atoms, di(meth)acrylates of polyethylene glycol or polypropylene glycol having a number average molecular weight of not more than 1500, such as not more than 1200, wherein these compounds are optionally modified with EO or PO, for example with 5 to 15 EO and / or PO;

[0027] Including but not limited to: 2-hydroxy-3-acryloxypropyl (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 2-methyl-1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) acrylate, ethoxylated 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, propoxylated neopentyl glycol di (meth) acrylate, polyethylene glycol # 400 di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol # 400 di (meth) acrylate, polypropylene glycol ( di(meth)acrylate, bisphenol A type di(meth)acrylate (which may contain different alkoxy segments such as EO and PO), hydrogenated bisphenol A type di(meth)acrylate (which may contain different alkoxy segments such as EO and PO), dicyclopentadiene, 2,2-bis(4-(methacryloyloxypolyethoxy)phenyl)propane (the average number of EO units is 5 to 15 per molecule), etc. One or more of them may be used.

[0028] As the radical polymerizable bifunctional compound, preferred are polyethylene glycol di(meth)acrylate and 2,2-bis(4-(methacryloyloxypolyethoxy)phenyl)propane (average number of EO units is 5-15 per molecule) having a number average molecular weight of not more than 1200 (eg, not more than 800), and mixtures thereof.

[0029] As one embodiment of the present invention, the weight of the free radical polymerizable bifunctional compound is 0-80%, for example 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70% or 80% based on the total solids of the photocurable composition of the present invention.

[0030] Among them, the radical polymerizable trifunctional or higher functional compound is preferably a compound having three or more (meth)acrylate groups.

[0031] Including but not limited to: trimethylolpropane triacrylate, trimethylolmethane triacrylate, ethylene oxide modified trimethylolpropane triacrylate, propylene oxide modified trimethylolpropane triacrylate, epichlorohydrin modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetra(meth)acrylate, tetramethylolmethane tetraacrylate, ethylene oxide modified phosphoric acid triacrylate, propylene oxide modified phosphoric acid triacrylate, epichlorohydrin modified glycerol triacrylate, dipentaerythritol hexaacrylate, di(trimethylol)propane tetraacrylate, or multifunctional acrylates represented by their silsesquioxane modified products, or their corresponding methacrylate monomers, ε-caprolactone modified triacryloxyethyl isocyanurate, etc.

[0032] As one embodiment of the present invention, the weight of the free radical polymerizable trifunctional or higher functional compound is 0-80%, for example 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70% or 80% based on the total solids of the photocurable composition of the present invention.

[0033] As another embodiment of the present invention, the free radical polymerizable compound is in the form of a resin (including an oligomer or a prepolymer).

[0034] The free radical polymerizable compound in the form of resin includes, but is not limited to: epoxy (meth) acrylate resin, polyester (meth) acrylate, polyurethane (meth) acrylate, ethylenically unsaturated polyester, amino (meth) acrylate resin, photoimageable alkali-soluble resin, etc. Preferably, epoxy (meth) acrylate resin, polyester (meth) acrylate, polyurethane (meth) acrylate or a combination thereof is used.

[0035] Among them, the epoxy (meth) acrylate resin is preferably bisphenol A epoxy (meth) acrylate, bisphenol A epoxy acrylate diluted with tripropylene glycol di(meth) acrylate or a combination thereof; for example, bisphenol A epoxy acrylate WSR-U125 from Wuxi Resin Factory, bisphenol A epoxy acrylate 621A-80 diluted with 20% tripropylene glycol diacrylate from Changxing Chemical Company of China Taiwan, modified bisphenol A epoxy acrylate 623-100 from Changxing Chemical Company of China Taiwan, modified bisphenol A epoxy acrylate 6231A-80 diluted with 20% tripropylene glycol diacrylate from Changxing Chemical Company of China Taiwan.

[0036] Among them, the polyester (meth) acrylate is preferably a hyperbranched polyester acrylic resin with high functionality, especially a hyperbranched polyester acrylic resin with a functionality of 5-30, such as a hyperbranched polyester acrylic prepolymer with a functionality of 6-20. For example, hyperbranched polyester acrylic prepolymer 932-100 (6 functionality) from Wuxi Knox Company, hyperbranched polyester acrylic prepolymer CN2300 (8 functionality), CN2301 (9 functionality), CN2302 (16 functionality) from American Sartomer Company, etc. The polyester (meth) acrylate can also be mentioned as a polyester polyol acrylic resin diluted with 20% ethoxylated trimethylolpropane triacrylate.

[0037] Among them, the polyurethane (meth) acrylate is preferably an aliphatic polyurethane acrylate resin. For example, aliphatic polyurethane hexaacrylate 6145-100, 6161-100, aliphatic polyurethane diacrylate 611B-85 diluted with 15% 1,6-hexanediol diacrylate (HDDA), and aliphatic polyurethane diacrylate 6141H-80 from Changxing Chemical Company of Taiwan, China; aliphatic polyurethane acrylate CN9013 (9 functionalities) from Sartomer Company of the United States, aliphatic polyurethane acrylate CN966B85 (2 functionalities) diluted with 15% 1,6-hexanediol diacrylate (HDDA) from Sartomer Company of the United States, and aliphatic polyurethane acrylate CN962 (2 functionalities).

[0038] As one embodiment of the present invention, the weight of the free radical polymerizable compound in resin form is 10-80%, for example 15%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, preferably 15-75%, based on the total solid content of the photocurable composition.

[0039] The component (C) photoinitiator is a compound that is decomposed by irradiation with active energy rays such as ultraviolet rays or visible light to generate free radical species, cationic species or anionic species.

[0040] The component (C) photoinitiator includes, but is not limited to, acetophenone photoinitiators, benzoin photoinitiators, benzophenone photoinitiators, thioxanthone photoinitiators, acylphosphine oxide photoinitiators, hexaaryl diimidazole compounds, oxime ester compounds, etc. These can be used alone or in combination of two or more. When an acylphosphine oxide photoinitiator that is easily cured by energy rays in the visible light region is added to the composition, the composition itself tends to turn yellow, but from the perspective of improving photocurability, it is preferred to include an acylphosphine oxide photoinitiator.

[0041] Acetophenone-based photoinitiators include, but are not limited to, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, benzyl dimethyl ketal, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]acetone oligomers, and the like.

[0042] The benzoin-based photoinitiator includes, but is not limited to, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and the like.

[0043] Benzophenone-based photoinitiators include, but are not limited to, benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N,N-dimethyl-N-[2-(1-oxo-2-propenyloxy)ethyl]benzene ammonium bromide, and (4-benzoylbenzyl)trimethylammonium chloride.

[0044] Thioxanthone-based photoinitiators include, but are not limited to, 2-isopropyl thioxanthone, 4-isopropyl thioxanthone, 2,4-diethyl thioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxy thioxanthone, 2-(3-dimethylamino-2-hydroxy)-3,4-dimethyl-9H-thioxanthone-9-one chloride, and the like.

[0045] The acylphosphine oxide-based photoinitiators include, but are not limited to, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, and the like.

[0046] The hexaarylbiimidazole compounds include, but are not limited to, 2-(o-chlorophenyl)-4,5-diphenyldiimidazole, 2,2,5-tris-(o-chlorophenyl)-4-(3,4-dimethoxyphenyl)-4',5'-diphenyldiimidazole, 2,4-bis-(o-chlorophenyl)-5-(3,4-dimethoxyphenyl)-diphenyldiimidazole, 2,4,5-tris-(o-chlorophenyl)-diphenyldiimidazole, 2-(o-chlorophenyl)-bis-4,5'-diphenyldiimidazole, 2,2,5-tris-(o-chlorophenyl)-4-(3,4-dimethoxyphenyl)-4',5'-diphenyldiimidazole, 2,4-bis-(o-chlorophenyl)-5-(3,4-dimethoxyphenyl)-diphenyldiimidazole, 2,4,5-tris-(o-chlorophenyl)-diphenyldiimidazole, 2-(o-chlorophenyl)-bis-4, 5-(3,4-dimethoxyphenyl)-diimidazole, 2,2'-bis-(2-fluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-diimidazole, 2,2'-bis-(2,3-difluoromethylphenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-diimidazole, 2,2'-bis-(2,4-difluorophenyl)-4,4',5,5'-tetrakis-(3-methoxyphenyl)-diimidazole, and the like.

[0047] The oxime ester compound includes, but is not limited to, 1-phenyl-1,2-propanedione-2-O-benzoyl oxime and 1-phenyl-1,2-propanedione-2-(O-ethoxycarbonyl)oxime, but is not limited thereto.

[0048] As one embodiment of the present invention, the weight of the photopolymerization initiator as component (C) is 0.1-10%, preferably 0.5-5%, based on the total solid content of the photocurable composition.

[0049] As an embodiment of the present invention, the photocurable composition of the present invention may optionally further comprise other additives, such as a leveling agent, an antioxidant, a colorant, a pigment, an inorganic filler and the like.

[0050] The weight of the additive is 0.5-10%, preferably 1-5%, such as 2% or 3%, based on the total solid content of the photocurable composition of the present invention.

[0051] The present invention also provides a method for preparing a multifunctional photocurable monomer, the preparation method comprising:

[0052] Step (1): esterifying and protecting 4-hydroxypyridine-2,6-dicarboxylic acid of formula (a) using halide A and alcohol A, and purifying the product to obtain formula (b);

[0053] Step (2): using halide B and alcohol B represented by formula (c) to carry out halogenation reaction, and purifying the product to obtain formula (d);

[0054] Step (3): performing a grafting reaction using the compound represented by formula (b) and formula (d), and purifying the product to obtain formula (e);

[0055] Step (4): using alcohol C and the compound represented by formula (e) to carry out a hydrolysis reaction, and purifying the product to obtain a multifunctional photocurable monomer of formula (I);

[0056] The reaction intermediates and product structures of the method are as follows:

[0057] Step (1)

[0058] Step (2)

[0059] Step (3)

[0060] Step (4)

[0061] in,

[0062] R 1 , R 2 , R 3 , R 4 , the definition of n is the same as described above.

[0063] In step (1), the temperature of the esterification protection reaction is 80-100° C., and the reaction time is 6-48 hours; preferably, the reaction temperature is 80-90° C., and the reaction time is 12-36 hours.

[0064] In step (1), the product purification step refers to desolventizing by distillation under reduced pressure, neutralizing with sodium carbonate, and recrystallizing with ethanol aqueous solution, and one or more of these steps can be performed once or multiple times.

[0065] In step (1), the halide A is a halogenated sulfone, specifically one or more of thionyl chloride, thionyl bromide, etc.

[0066] In step (1), the alcohol A is C 1 -C 4 of alkyl alcohols.

[0067] In step (1), the molar ratio of the halide A, alcohol A, and 4-hydroxypyridine-2,6-dicarboxylic acid is (1-20):(2-60):1; preferably, 2-15:5-40:1.

[0068] In step (2), the halogenation reaction temperature is 40-100° C., and the reaction time is 6-48 hours; preferably, the reaction temperature is 40-80° C., and the reaction time is 12-36 hours.

[0069] In step (2), the product purification step refers to desolventizing by distillation under reduced pressure, washing with ether, washing with water, extracting with ether, drying with anhydrous magnesium sulfate, and desolventizing by distillation under reduced pressure. One or more of these steps may be performed once or multiple times.

[0070] In step (2), the halide B is a phosphorus halide, specifically phosphorus tribromide.

[0071] In step (2), the alcohol B is a polyethylene glycol chain whose terminal groups are all hydroxyl groups.

[0072] In step (2), the molar ratio of the halide B to the alcohol B is 1:(0.6-2); preferably, it is 1:0.7-1.5.

[0073] In step (3), the grafting reaction temperature is 60-100° C., and the reaction time is 0.5-7 days; preferably, the reaction temperature is 80-100° C., and the reaction time is 2-5 days.

[0074] In step (3), the product purification step refers to the solvent removal by rotary evaporation.

[0075] In step (3), the molar ratio of formula (b) to formula (d) is (2-10):1; preferably, 2-6:1.

[0076] In step (4), the temperature of the hydrolysis reaction is 40-100° C., and the reaction time is 1-48 hours; preferably, the reaction temperature is 60-90° C., and the reaction time is 6-36 hours.

[0077] In step (4), the product purification step refers to desolventizing by distillation under reduced pressure and passing through a reverse C18 chromatographic column. One or more of these steps may be performed once or multiple times.

[0078] In step (4), the alcohol C is a C connecting the double bond and the hydroxyl group. 1 -C 4 Alkyl alcohols or C-linked acrylates and hydroxyl groups 1 -C 4 Alkyl alcohols.

[0079] In step (4), the molar ratio of the alcohol C to the compound of formula (e) is (4-20):1; preferably, 4-12:1.

[0080] The present invention also proposes the use of the multifunctional photocurable monomer or the photocurable composition in the preparation of photocurable coatings, photocurable coatings, photocurable inks, photocurable adhesives, photoresists, printed circuit board dry film resists, printed circuit board ink resists, sealants, photolithographic materials, holographic recording materials, 3D or 4D printing materials, lithographic materials, optical device preparation materials or materials for improving mechanical properties.

[0081] The beneficial effect of the present invention is that: the present invention proposes a multifunctional photocurable monomer and a preparation method thereof, wherein the structure of the multifunctional photocurable monomer is a benzene ring as a core group, comprising a plurality of pyridine groups and UV crosslinking end groups. The present invention can be applied to the photocurable reaction system required in the formulation composition such as coatings, inks, adhesives, etc. By using the photocurable monomer, the hydrophilicity, rigidity and crosslinking degree of the photocurable reaction system can be adjusted, and the adhesion, hardness and other properties of the formulation composition can be effectively improved. DETAILED DESCRIPTION

[0082] In conjunction with the following specific examples, the process, conditions and experimental methods of implementing the present invention are further described in detail, comprehensively and accurately. It should be understood that the specific examples described herein are only used to explain the present invention and are not used to limit the present invention.

[0083] Example 1-4 Preparation method of photocurable monomer formula (I)

[0084]

[0085] Add thionyl chloride dropwise to an ethanol solution in an ice-salt bath, then add 4-hydroxypyridine-2,6-dicarboxylic acid of formula (a), and stir the reaction at room temperature for 24 hours; then reflux at 80° C. for 2 hours, and introduce the generated acidic gas into an alkaline solution for neutralization; after the reaction solution is cooled, the solvent is removed by vacuum distillation, and the crude product is washed with a sodium carbonate solution until it is neutral, and the filtered filter cake is placed in an ethanol-water solution for recrystallization, and finally vacuum dried to obtain a white needle-shaped crystalline product of formula (b).

[0086] Tetraethylene glycol (c) (or other linear polyethylene glycols with hydroxyl groups at the end) is dissolved in chloroform, and a pyridine solution is added. Phosphorus tribromide is added dropwise in an ice-salt bath at -8°C, and the mixture is reacted at 46°C for 24 hours. After the reaction is completed, the solvent is removed by distillation under reduced pressure, and the product is dissolved in an ether solution, washed with water three times, and the aqueous phase is taken, and an ether solution is added for extraction. Anhydrous magnesium sulfate is added to the extracted organic phase, and the mixture is dried overnight. The ether solvent is then removed by distillation under reduced pressure to obtain a yellow oily product (d).

[0087] Then, the product of formula (b) was dissolved in butanone, potassium carbonate and product of formula (d) (where n is the degree of polymerization of polyethylene glycol, which can be determined according to the final desired structure of the photocurable product) were added, and the reaction was carried out under nitrogen protection for 4 days. The progress of the reaction was tracked by TLC, and the eluent was 1:19 methanol and dichloromethane. After the reaction was completed, the solvent was removed by vacuum distillation to obtain product of formula (e); then the product was dissolved in ethanol aqueous solution, and R 1 To R 4Any one or more reagents having a main body, a double bond and a hydroxyl group as the end group are refluxed for reaction for 12 hours, and the solvent is distilled off under reduced pressure after the reaction. The crude product is purified 10 times by a reverse C18 column using pure water as the eluent, and freeze-dried to finally obtain a pure white fluffy product of formula (I).

[0088] The specific embodiment structure can be exemplified by the following formula (I-1) (the product obtained in Example 1), formula (I-2) (the product obtained in Example 2), formula (I-3) (the product obtained in Example 3), formula (I-4) (the product obtained in Example 4), etc.

[0089]

[0090] Application Example 1 Application of Photocuring System

[0091] The raw materials used in this embodiment are listed as follows (see Table 1):

[0092] (A) Multifunctional photocurable monomers prepared in Examples 1-4 of the present invention

[0093] I-1, I-2, I-3, I-4

[0094] (B) Photopolymerizable compound

[0095] B1: tripropylene glycol diacrylate (TPGDA, purchased from Jiangsu Sanmu)

[0096] B2: trimethylolpropane triacrylate (TMPTA, purchased from Jiangsu Sanmu)

[0097] B3: Hydroxyethyl methacrylate (HEMA, purchased from Jiangsu Sanmu)

[0098] (C) Photoinitiator

[0099] C1: 2,4,6-trimethylbenzoyldiphenoxyphosphine TPO (purchased from Hubei Gurun Technology Co., Ltd.)

[0100] C2: 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]ethanone 1-(O-acetyl oxime) OXE02 (purchased from Hubei Gurun Technology Co., Ltd.)

[0101] Table 1

[0102]

[0103] The photocurable compositions obtained by directly mixing the components in Examples 1-4 and Comparative Examples 1-2 in Table 1 were respectively coated on glass with a coating thickness of 150 μm and irradiated with a 385 nm LED lamp for 10 s with a light intensity of 30 mW cm -2 .

[0104] The test standards for each performance index in Application Example 1 are as follows, and the specific test results are shown in Table 2:

[0105] Pencil hardness: According to the national standard GB / T6739 "Pencil Determination of Paint Film Hardness", the pencil hardness gradually decreases from 6H, 5H, 4H, 3H, 2H, H, HB, B, 2B, 3B, 4B, 5B, and 6B.

[0106] Adhesion: According to the national standard GB / T9286 "Scratching test for paint and varnish film". The adhesion level is 0-5, the larger the value, the smaller the adhesion.

[0107] Table 2

[0108]

[0109]

[0110] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A multifunctional photocurable monomer, characterized in that: Its structure is composed of polyethylene glycol as the core group, including a pyridine group and a UV cross-linking end group, as shown in formula (I): in, R1, R2, R3, and R4 are one of the groups composed of the following structures, one end is an ester bond or an amide bond, the other end is a double bond or an acrylate, the middle segment is a C1-C4 straight chain or branched alkane, and R1, R2, R3, and R4 can be of the same structure or different structures; n is the degree of polymerization 1-8.

2. A photocurable composition, characterized in that: It comprises: (A) the multifunctional photocurable monomer as claimed in claim 1, wherein the weight of the multifunctional photocurable monomer accounts for 0.1-60% of the total solid content of the photocurable composition.

3. The photocurable composition according to claim 2, characterized in that: It further contains (B) a photopolymerizable compound and (C) a photoinitiator.

4. The photocurable composition according to claim 3, characterized in that The (B) photopolymerizable compound is a radical polymerizable compound containing an ethylenically unsaturated group; the radical polymerizable compound may be in the form of a monomer or a resin.

5. The photocurable composition according to claim 4, characterized in that: The photopolymerizable compound is epoxy (meth) acrylate, polyester (meth) acrylate, polyurethane (meth) acrylate, ethylenically unsaturated polyester, amino (meth) acrylate resin, photo-imaging alkali-soluble resin or a combination thereof; the weight of the photopolymerizable compound accounts for 10 to 90% of the total solid content of the photocurable composition.

6. The photocurable composition according to claim 3, characterized in that: The (C) photoinitiator comprises a photoinitiator capable of initiating free radical polymerization, and its weight accounts for 0.1-10% of the total solid content of the photocurable composition.

7. The photocurable composition according to any one of claims 2 to 6, characterized in that: The photocurable composition comprises one or more additives selected from the group consisting of a leveling agent, an antioxidant, a colorant, a pigment, and an inorganic filler.

8. A method for preparing a multifunctional photocurable monomer, characterized in that: The preparation method is: Step (1): esterifying and protecting 4-hydroxypyridine-2,6-dicarboxylic acid of formula (a) using halide A and alcohol A, and purifying the product to obtain formula (b); Step (2): using halide B and alcohol B represented by formula (c) to carry out halogenation reaction, and purifying the product to obtain formula (d); Step (3): performing a grafting reaction using the compound represented by formula (b) and formula (d), and purifying the product to obtain formula (e); Step (4): using alcohol C and the compound represented by formula (e) to carry out a hydrolysis reaction, and purifying the product to obtain a multifunctional photocurable monomer of formula (I); The reaction intermediates and product structures of the method are as follows: Step (1) Step (2) Step (3) Step (4) in, R1, R2, R3, R4 and n are as defined in claim 1.

9. The method according to claim 8, characterized in that In step (1), the halide A is a halogenated sulfone; In step (1), the alcohol A is a C1-C4 alkyl alcohol; In step (2), the halide B is a phosphorus halide; In step (2), the alcohol B is a polyethylene glycol chain whose terminal groups are all hydroxyl groups; In step (4), the alcohol C is a C1-C4 alkyl alcohol connecting a double bond and a hydroxyl group or a C1-C4 alkyl alcohol connecting an acrylate and a hydroxyl group.

10. The method according to claim 8, characterized in that In step (1), the temperature of the esterification protection reaction is 80-100° C., and the reaction time is 6-48 hours; The product purification step refers to desolventizing by distillation under reduced pressure, neutralizing with sodium carbonate, and recrystallizing with ethanol aqueous solution, and one or more of these steps may be performed once or multiple times; In step (2), the halogenation reaction temperature is 40-100° C., and the reaction time is 6-48 hours; The product purification step refers to desolventizing by distillation under reduced pressure, washing with ether, washing with water, extracting with ether, drying with anhydrous magnesium sulfate, and desolventizing by distillation under reduced pressure, and one or more of these steps may be performed once or multiple times; In step (3), the grafting reaction temperature is 60-100° C., and the reaction time is 0.5-7 days; The product purification step refers to the solvent removal by rotary evaporation; In step (4), the hydrolysis reaction temperature is 40-100° C., and the reaction time is 1-48 hours; The product purification step refers to desolventizing by distillation under reduced pressure and passing through a reverse C18 chromatographic column. One or more of these steps can be performed once or multiple times.

11. Use of the multifunctional photocurable monomer according to claim 1 or the photocurable composition according to any one of claims 2 to 7 in the preparation of photocurable coatings, photocurable coatings, photocurable inks, photocurable adhesives, photoresists, printed circuit board dry film resists, printed circuit board ink resists, sealants, photolithographic materials, holographic recording materials, 3D or 4D printing materials, lithographic materials, materials for preparing optical devices, or materials for improving mechanical properties.

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