High-temperature-resistant invisible anti-counterfeiting ink and preparation method thereof

Abstract

The invention relates to the technical field of ink, and discloses high-temperature-resistant invisible anti-counterfeiting ink and a preparation method thereof.The high-temperature-resistant invisible anti-counterfeiting ink is prepared from, by weight, 100 parts of waterborne polyurethane acrylic resin, 100-130 parts of deionized water, 2.3-2.8 parts of photoinitiator, 8-10 parts of reactive diluent and 1.2-5 parts of styryl europium fluorescent complex; the styryl europium fluorescent complex is added, so that the ink is colorless and transparent in a normal state, can present a unique red fluorescence characteristic after being irradiated by an ultraviolet lamp, and has good practical application in the aspects of invisible anti-counterfeiting ink and the like. And the styryl europium fluorescent complex contains two styrene groups, and the styryl europium fluorescent complex is subjected to a cross-linking reaction with the reactive diluent and the urethane acrylate through ultraviolet irradiation and the action of the photoinitiator, so that the high-temperature resistance of a paint film can be improved, and meanwhile, the water absorption rate of the adhesive film is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of inks, and in particular to a high temperature resistant invisible anti-counterfeiting ink and a preparation method thereof. Background Art

[0002] UV curing ink has the advantages of fast drying speed, convenient construction, no organic solvent, green and pollution-free. It is widely used in packaging materials, building decoration, printed circuit boards, etc. UV curing ink mainly consists of binders, active diluents, fillers, additives, etc. Among them, the preparation method of polyurethane acrylate binder is simple, low cost, good curing performance, and is widely used. Traditional polyurethane acrylate light curing ink has the problem of poor water resistance. The development of high-performance functional light curing ink is a research hotspot.

[0003] Invisible anti-counterfeiting ink is a functional ink, which is mainly divided into thermal color change anti-counterfeiting, fluorescent anti-counterfeiting, magnetic anti-counterfeiting and other products. Among them, the fluorescent anti-counterfeiting technology is to add fluorescent materials to the ink. When the ink is irradiated by a light source such as an ultraviolet lamp, it can emit unique fluorescent luminescence characteristics. CN109825130B discloses a multi-responsive fluorescent ink and a preparation method. Polyurethane, acrylic resin and other polymer resins, europium salts, terbium salts and other rare earth metal salts, N-(pyridine-2-yl)-benzoyl acetamide and other organic ligands are used as raw materials. The obtained multi-responsive fluorescent ink has the advantages of high anti-counterfeiting level and strong anti-counterfeiting ability. However, the patent does not improve the high temperature resistance and water resistance of the ink. Summary of the invention

[0004] The technical problem solved by the present invention is: to provide a high temperature resistant invisible anti-counterfeiting ink and a preparation method thereof, so as to solve the problems that the traditional polyurethane ink has poor high temperature resistance and does not have fluorescent luminescence characteristics.

[0005] The technical solution provided by the present invention is: a high-temperature resistant invisible anti-counterfeiting ink, comprising 100 parts by weight of aqueous polyurethane acrylic resin, 100-130 parts by weight of deionized water, 0.5-1.2 parts by weight of leveling agent, 0.8-1.4 parts by weight of defoaming agent, 2.3-2.8 parts by weight of photoinitiator, 8-10 parts by weight of active diluent, and 1.2-5 parts by weight of styrene-based europium fluorescent complex.

[0006] The preparation method of the styryl europium fluorescent complex is as follows:

[0007] Add ethanol and dibenzoylmethane to the reaction bottle, add sodium hydroxide aqueous solution to adjust the pH to 6.5-7, then add europium trichloride, heat to 45-50°C, stir and react for 1-1.5h, then add styryl o-phenanthroline monomer, stir and react for 6-8h, filter, wash with ethanol and water, and dry to obtain styryl europium fluorescent complex. The reaction mechanism is:

[0008]

[0009] Furthermore, the photoinitiator 1173, the active diluent is tripropylene glycol diacrylate or 1,6-hexanediol diacrylate.

[0010] Furthermore, the molar ratio of dibenzoylmethane, europium trichloride, and styryl-o-phenanthroline monomer is (2.6-3):1:(1-1.1).

[0011] Further, the preparation method of styryl-o-phenanthroline is as follows: in an ice bath, add 1,4-dioxane, cyanuric chloride, 1,10-phenanthroline-4-ol to a reaction bottle, drop sodium hydroxide aqueous solution, stir and react for 4-6 hours, then add 4-hydroxystyrene, drop sodium hydroxide aqueous solution, heat to 80-90°C, react for 12-18 hours, add hydrochloric acid solution to neutralize after cooling, remove 1,4-dioxane by vacuum distillation, add dichloromethane to extract, separate and dry the organic phase with anhydrous sodium sulfate, filter and heat the filtrate to volatilize until a precipitate is precipitated, then cool and recrystallize in an ice bath to obtain styryl-o-phenanthroline. The reaction formula is:

[0012]

[0013] Furthermore, the molar ratio of cyanuric chloride, 1,10-phenanthroline-4-olline, sodium hydroxide, and 4-hydroxystyrene is 1:1:(3.6-4.2):(2-2.4).

[0014] Furthermore, the preparation method of the high temperature resistant invisible anti-counterfeiting ink is: add deionized water, water-based polyurethane acrylic resin, leveling agent, defoaming agent, active diluent, styrene-based europium fluorescent complex into a container, mix and grind, and then add a photoinitiator to obtain the high temperature resistant invisible anti-counterfeiting ink.

[0015] The invention has the following technical effects: the invention uses cyanuric chloride to react with 1,10-phenanthroline-4-olline and 4-hydroxystyrene in sequence to obtain a novel styryl o-phenanthroline coordination, and then uses dibenzoylmethane as a second ligand and europium trichloride as a central coordination ion to obtain a styryl europium fluorescent complex.

[0016] The present invention uses polyurethane acrylate as a connecting material of ultraviolet curing ink, and is compounded with active diluents such as styrene-based europium fluorescent complex, photoinitiator 1173, tripropylene glycol diacrylate, etc. to obtain high-temperature resistant invisible anti-counterfeiting ink. The europium ions in the styrene-based europium fluorescent complex absorb ultraviolet light. When a certain excitation energy is reached, the europium ions undergo energy level transitions, and the europium ions transition from the ground state to the excited state, and then transition from the excited state back to the ground state, at which time energy is released and photons are emitted, presenting red fluorescent light, so that the ink is colorless and transparent under normal conditions, and can present unique red fluorescent characteristics after being irradiated by ultraviolet light. It has good practical applications in invisible anti-counterfeiting inks and inks.

[0017] The styrene-based europium fluorescent complex of the present invention contains two styrene groups, which undergo cross-linking reactions with active diluents and polyurethane acrylates after being irradiated with ultraviolet light and acted upon by a photoinitiator, thereby grafting heat-resistant triazine, benzene rings and o-phenanthroline condensed rings into the polyurethane acrylate molecular chain, significantly improving the high temperature resistance of the paint film and exhibiting a higher thermal decomposition temperature.

[0018] After the styrene-based europium fluorescent complex of the present invention is cured and cross-linked with polyurethane acrylate, the cross-linking degree between molecular chains is increased, which is beneficial to improving the pencil hardness of the paint film. At the same time, the benzene ring and the o-phenanthroline condensed ring are hydrophobic, forming a hydrophobic cross-linking network in the film, reducing the water absorption rate of the film, which is beneficial to improving the water resistance of the ink. DETAILED DESCRIPTION

[0019] The specific implementation of the present invention is further described below in conjunction with the examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention, and cannot be used to limit the protection scope of the present invention.

[0020] The waterborne polyurethane acrylate of the present invention is VOK-UA 8983Aqua, produced by Guangzhou Si Tu Yuan Chemical. The CAS number of 1,10-phenanthroline-4-ol is 23443-31-4, the CAS number of cyanuric chloride is 108-77-0, and the CAS number of 4-hydroxystyrene is 2628-17-3.

[0021] Example 1

[0022] (1) In an ice bath, 20 mL of 1,4-dioxane, 5 mmol of cyanuric chloride, and 5 mmol of 1,10-phenanthroline-4-ol are added to a reaction bottle, and 2 mL of an aqueous solution containing 6 mmol of sodium hydroxide is added dropwise, and the reaction is stirred for 5 h. Then, 10 mmol of 4-hydroxystyrene is added, and 4 mL of an aqueous solution containing 14 mmol of sodium hydroxide is added dropwise, and the reaction is heated to 80° C. for 18 h. After cooling, a hydrochloric acid solution is added for neutralization, and 1,4-dioxane is removed by vacuum distillation. Dichloromethane is added for extraction. After separation, the organic phase is dried over anhydrous sodium sulfate, and after filtering, the filtrate is heated for volatilization until a precipitate is precipitated, and then cooled in an ice bath for recrystallization to obtain styryl-o-phenanthroline.

[0023] (2) Add ethanol and 8.1 mmol of dibenzoylmethane to the reaction flask, add sodium hydroxide aqueous solution to adjust the pH to 6.5, then add 3 mmol of europium trichloride, heat to 45° C., stir and react for 1 hour, then add 3 mmol of styryl-o-phenanthroline monomer, stir and react for 8 hours, filter, wash with ethanol and water, and dry to obtain a styryl-europium fluorescent complex.

[0024] (3) 100 g of deionized water, 100 g of water-based polyurethane acrylic resin, 0.5 g of leveling agent BKY333, 1.2 g of defoaming agent TEGO Foamex 1488, 10 g of active diluent tripropylene glycol diacrylate, and 1.2 g of styrene-based europium fluorescent complex were added to a container, mixed and ground, and then 2.6 g of photoinitiator 1173 were added to obtain a high-temperature resistant invisible anti-counterfeiting ink.

[0025] Example 2

[0026] (1) In an ice bath, 15 mL of 1,4-dioxane, 5 mmol of cyanuric chloride, and 5 mmol of 1,10-phenanthroline-4-ol are added to a reaction bottle, and 2 mL of an aqueous solution containing 6 mmol of sodium hydroxide is added dropwise, and the reaction is stirred for 4 h. Then, 10 mmol of 4-hydroxystyrene is added, and 4 mL of an aqueous solution containing 15 mmol of sodium hydroxide is added dropwise, and the reaction is heated to 85° C. for 18 h. After cooling, a hydrochloric acid solution is added for neutralization, and 1,4-dioxane is removed by vacuum distillation. Dichloromethane is added for extraction. After separation, the organic phase is dried over anhydrous sodium sulfate, filtered, and the filtrate is heated for volatilization until a precipitate is precipitated, and then cooled in an ice bath for recrystallization to obtain styryl-o-phenanthroline.

[0027] (2) Add ethanol and 9 mmol of dibenzoylmethane to the reaction flask, add sodium hydroxide aqueous solution to adjust the pH to 7, then add 3 mmol of europium trichloride, heat to 45° C., stir and react for 1.5 hours, then add 3.3 mmol of styryl-o-phenanthroline monomer, stir and react for 6 hours, filter, wash with ethanol and water, and dry to obtain a styryl-europium fluorescent complex.

[0028] (3) 100 g of deionized water, 100 g of water-based polyurethane acrylic resin, 1.2 g of leveling agent BKY333, 0.8 g of defoaming agent TEGO Foamex 1488, 9.2 g of active diluent 1,6-hexanediol diacrylate, and 3 g of styrene-based europium fluorescent complex were added to a container, mixed and ground, and then 2.3 g of photoinitiator 1173 was added to obtain a high-temperature resistant invisible anti-counterfeiting ink.

[0029] Example 3

[0030] (1) In an ice bath, 20 mL of 1,4-dioxane, 5 mmol of cyanuric chloride, and 5 mmol of 1,10-phenanthroline-4-ol are added to a reaction bottle, and 2 mL of an aqueous solution containing 6 mmol of sodium hydroxide is added dropwise, and the reaction is stirred for 6 h. Then, 10 mmol of 4-hydroxystyrene is added, and 4 mL of an aqueous solution containing 12 mmol of sodium hydroxide is added dropwise, and the reaction is heated to 90° C. for 12 h. After cooling, a hydrochloric acid solution is added for neutralization, and 1,4-dioxane is removed by vacuum distillation. Dichloromethane is added for extraction. After separation, the organic phase is dried over anhydrous sodium sulfate, filtered, and the filtrate is heated for volatilization until a precipitate is precipitated, and then cooled in an ice bath for recrystallization to obtain styryl-o-phenanthroline.

[0031] (2) Add ethanol and 7.8 mmol of dibenzoylmethane to the reaction flask, add sodium hydroxide aqueous solution to adjust the pH to 6.5, then add 3 mmol of europium trichloride, heat to 50° C., stir and react for 1 hour, then add 3 mmol of styryl-o-phenanthroline monomer, stir and react for 6 hours, filter, wash with ethanol and water, and dry to obtain a styryl-europium fluorescent complex.

[0032] (3) 130 g of deionized water, 100 g of water-based polyurethane acrylic resin, 1.2 g of leveling agent BKY333, 1.4 g of defoaming agent TEGO Foamex 1488, 8 g of active diluent 1,6-hexanediol diacrylate, and 5 g of styrene-based europium fluorescent complex were added to a container, mixed and ground, and then 2.8 g of photoinitiator 1173 was added to obtain a high-temperature resistant invisible anti-counterfeiting ink.

[0033] Comparative Example 1

[0034] (1) 100 g of deionized water, 100 g of water-based polyurethane acrylic resin, 0.5 g of leveling agent BKY333, 1.2 g of defoaming agent TEGO Foamex 1488, and 10 g of active diluent tripropylene glycol diacrylate were added to a container, mixed and ground, and then 2.6 g of photoinitiator 1173 was added to obtain a high temperature resistant invisible anti-counterfeiting ink.

[0035] Comparative Example 2

[0036] (1) In an ice bath, 20 mL of 1,4-dioxane, 5 mmol of cyanuric chloride, and 5 mmol of 1,10-phenanthroline-4-ol are added to a reaction bottle, and 2 mL of an aqueous solution containing 6 mmol of sodium hydroxide is added dropwise, and the reaction is stirred for 5 h. Then, 10 mmol of 4-hydroxystyrene is added, and 4 mL of an aqueous solution containing 14 mmol of sodium hydroxide is added dropwise, and the reaction is heated to 80° C. for 18 h. After cooling, a hydrochloric acid solution is added for neutralization, and 1,4-dioxane is removed by vacuum distillation. Dichloromethane is added for extraction. After separation, the organic phase is dried over anhydrous sodium sulfate, and after filtering, the filtrate is heated for volatilization until a precipitate is precipitated, and then cooled in an ice bath for recrystallization to obtain styryl-o-phenanthroline.

[0037] (2) 100 g of deionized water, 100 g of water-based polyurethane acrylic resin, 0.5 g of leveling agent BKY333, 1.2 g of defoaming agent TEGO Foamex 1488, 10 g of active diluent tripropylene glycol diacrylate, and 1.2 g of styryl o-phenanthroline were added to a container, mixed and ground, and then 2.6 g of photoinitiator 1173 were added to obtain a high temperature resistant invisible anti-counterfeiting ink.

[0038] Comparative Example 3

[0039] (1) Add ethanol and 8.1 mmol dibenzoylmethane to a reaction flask, add sodium hydroxide aqueous solution to adjust the pH to 6.5, then add 3 mmol europium trichloride, heat to 45°C, stir and react for 1 hour, then add 3 mmol 1,10-phenanthroline, stir and react for 8 hours, filter, wash with ethanol and water, and dry to obtain a europium fluorescent complex. The reaction mechanism is:

[0040]

[0041] (2) Add 100 g of deionized water, 100 g of water-based polyurethane acrylic resin, 0.5 g of leveling agent BKY333, 1.2 g of defoaming agent TEGO Foamex 1488, 10 g of active diluent tripropylene glycol diacrylate, and 1.2 g of europium fluorescent complex into a container, mix well, grind, and then add 2.6 g of photoinitiator 1173 to obtain a high temperature resistant invisible anti-counterfeiting ink.

[0042] The high temperature resistant invisible anti-counterfeiting ink is coated on the surface of the substrate and irradiated in a light curing machine for 1 minute to form a paint film. The power of the light curing machine is 800W.

[0043] Place the paint film in a dark place for 48 hours, then observe the color of the paint film, then irradiate the paint film under ultraviolet light for 5 minutes and observe the color of the paint film.

[0044] Table 1

[0045]

[0046] Weigh 8 mg of the paint film and place it in a thermogravimetric analyzer for thermal performance analysis in a nitrogen atmosphere with a heating rate of 10°C / min and a test temperature of 25-700°C. 5％ The temperature at which the mass loss is 5%. 10％ The temperature at which the mass is lost by 10%.

[0047] Table 2

[0048]

[0049]

[0050] The pencil hardness of the paint film is tested according to GB / T 6739-2022 method.

[0051] Pour the high-temperature resistant invisible anti-counterfeiting ink into the mold, irradiate it in a light curing machine to make a film sample with a specification of 6cm×6cm×0.5cm, dry it at 100℃ for 2h, weigh it, and then soak it in deionized water for 24h. Take out the film, absorb the excess water on the surface with filter paper, weigh it, and calculate the water absorption rate R.

[0052] R = (mass after water absorption - mass before water absorption) ÷ mass before water absorption × 100%.

[0053] Table 3 Pencil hardness and water absorption

[0054] Pencil hardness (H) Water absorption (%) Example 1 2H 11.27 Example 2 3H 9.36 Example 3 3H 4.65 Comparative Example 1 H 18.72 Comparative Example 2 2H 11.32 Comparative Example 3 H 18.59

[0055] As shown in Table 1-3, the polyurethane acrylate ink of Example 1-3 is colorless and transparent under normal conditions, and exhibits unique red fluorescence characteristics after being irradiated by ultraviolet light. This is because the europium ions in the added styrene-based europium fluorescent complex absorb ultraviolet light, and when a certain excitation energy is reached, the europium ions undergo energy level transitions, and the europium ions transition from the ground state to the excited state, and then transition from the excited state back to the ground state, at which time energy is released and photons are emitted, presenting red fluorescence light. In addition, the added styrene-based europium fluorescent complex contains two styrene groups, which undergo cross-linking reactions with active diluents and polyurethane acrylates after ultraviolet irradiation and the action of photoinitiators, thereby grafting heat-resistant triazine, benzene rings and o-phenanthroline condensed rings into the polyurethane acrylate molecular chain, significantly improving the high temperature resistance of the paint film and showing a higher thermal decomposition temperature. After the styrene-based europium fluorescent complex is cured and cross-linked with polyurethane acrylate, the cross-linking degree between the molecular chains is increased, which is beneficial to improving the pencil hardness of the paint film. At the same time, the benzene ring and the o-phenanthroline condensed ring are hydrophobic, forming a hydrophobic cross-linking network in the film, reducing the water absorption rate of the film, which is beneficial to improving the water resistance of the ink.

[0056] The styryl-o-phenanthroline without europium ions added in Comparative Example 2 has no fluorescent luminescence performance in the paint film, and the paint film has no color change before and after ultraviolet light irradiation. However, styryl-o-phenanthroline contains two styrene groups, which can react with the reactive diluent and polyurethane acrylate to cross-link, thereby improving the hardness and thermal decomposition temperature of the paint film, reducing the water absorption rate, and improving the water resistance of the ink.

[0057] Comparative Example 3 uses conventional dibenzoylmethane and 1,10-phenanthroline as ligands to obtain a europium fluorescent complex, which can give the ink film monomer fluorescent luminescence properties. However, the europium fluorescent complex does not contain an olefin group and cannot undergo a cross-linking reaction with an active diluent and polyurethane acrylate. The hardness and thermal decomposition temperature of the film are low, the water absorption rate of the film is large, and the water resistance of the ink is poor.

[0058] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high temperature resistant invisible anti-counterfeiting ink, characterized in that: The high temperature resistant invisible anti-counterfeiting ink comprises 100 parts by weight of aqueous polyurethane acrylic resin, 100-130 parts by weight of deionized water, 0.5-1.2 parts by weight of leveling agent, 0.8-1.4 parts by weight of defoaming agent, 2.3-2.8 parts by weight of photoinitiator, 8-10 parts by weight of active diluent, and 1.2-5 parts by weight of styrene-based europium fluorescent complex; The preparation method of the styryl europium fluorescent complex is: Add ethanol, dibenzoylmethane, sodium hydroxide aqueous solution, and europium trichloride to a reaction bottle, heat to 45-50° C., stir to carry out a primary reaction, then add styryl-o-phenanthroline monomer, stir to carry out a secondary reaction, filter, wash, and dry to obtain a styryl-europium fluorescent complex; The styryl o-phenanthroline monomer has the following structural formula (I):

2. The high temperature resistant invisible anti-counterfeiting ink according to claim 1, characterized in that: The initiator is photoinitiator 1173, and the active diluent is tripropylene glycol diacrylate or 1,6-hexanediol diacrylate.

3. The high temperature resistant invisible anti-counterfeiting ink according to claim 1, characterized in that: The molar ratio of the dibenzoylmethane, europium trichloride and styryl o-phenanthroline monomer is (2.6-3):1:(1-1.1).

4. The high temperature resistant invisible anti-counterfeiting ink according to claim 1, characterized in that: The time of the primary reaction is 1-1.5 hours, and the time of the secondary reaction is 6-8 hours.

5. The high temperature resistant invisible anti-counterfeiting ink according to claim 1, characterized in that: The sodium hydroxide aqueous solution is added to adjust the pH to 6.5-7.

6. The high temperature resistant invisible anti-counterfeiting ink according to claim 3, characterized in that: The preparation method of styryl-o-phenanthroline comprises the following steps: adding 1,4-dioxane, cyanuric chloride and 1,10-phenanthroline-4-ol into a reaction bottle under an ice bath, dripping a sodium hydroxide aqueous solution, stirring and reacting for 4-6 hours, then adding 4-hydroxystyrene, dripping a sodium hydroxide aqueous solution, heating to 80-90° C., reacting for 12-18 hours, adding a hydrochloric acid solution for neutralization after cooling, performing reduced pressure distillation, extracting and separating, and recrystallizing to obtain styryl-o-phenanthroline.

7. The high temperature resistant invisible anti-counterfeiting ink according to claim 1, characterized in that: The molar ratio of cyanuric chloride, 1,10-phenanthroline-4-olline, sodium hydroxide and 4-hydroxystyrene is 1:1:(3.6-4.2):(2-2.4).

8. A method for preparing the high temperature resistant invisible anti-counterfeiting ink according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: adding deionized water, water-based polyurethane acrylic resin, leveling agent, defoaming agent, active diluent, and styrene-based europium fluorescent complex into a container, mixing and grinding, and then adding a photoinitiator to obtain high temperature resistant invisible anti-counterfeiting ink.

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