A method for preparing a bonded type rare earth modified waterborne polyurethane acrylate coating

Abstract

The application relates to a preparation method of a bonded type rare earth modified water-based polyurethane acrylate coating, which is prepared from europium oxide, 2,2-dimethylol propionic acid and diphenylformamid as raw materials, a hydroxyl-containing rare earth complex prepared from the raw materials is reacted with isophorone diisocyanate, polyethylene glycol, 2,2-dimethylol propionic acid and hydroxyethyl acrylate to obtain a prepolymer emulsion, the prepolymer emulsion is initiated by an initiator and is cured by ultraviolet light to obtain the bonded type rare earth modified water-based polyurethane acrylate coating. The rare earth modified water-based polyurethane acrylate coating contains the bonded type rare earth complex, has good compatibility with the water-based polyurethane acrylate, the prepolymer emulsion only needs to be initiated by the initiator and cured by the ultraviolet light, the obtained coating has good film-forming property and stability, the preparation method is simple, the coating is convenient to use, and the coating is suitable for the fields of water-soluble light-curing systems, luminescent coatings, luminescent inks, medical materials and the like.

Description

Technical Field

[0001] The invention relates to a method for preparing a bonded rare earth modified waterborne polyurethane acrylate coating, particularly in the technical field of ultraviolet curing coatings. Background Art

[0002] Rare earth polymer luminescent materials are functional polymers created by physically or chemically introducing luminescent rare earth ions into polymers. These materials combine the excellent stability and processing properties of polymer materials with the fluorescence properties of the rare earth ions, making them promising new materials. Rare earth polymer composites are classified into two types: doped and bonded. Doped rare earth polymer composites present several challenges: When preparing rare earth polymer materials using the doping method, the addition of the rare earth complex leads to poor dispersion, agglomeration, and reduced compatibility with the polymer. This reduces the transparency and fluorescence properties of the composite, making it difficult to produce rare earth polymer luminescent materials with high rare earth content and good transparency, thus limiting their application. Rare earth doping also reduces the solvent and water resistance of the composite. Furthermore, rare earth polymer composites require long drying times and have slow curing. Therefore, the compatibility between the rare earth and the polymer, film-forming properties, and stability of rare earth-doped polymers remain key challenges.

[0003] To reduce the fluorescence quenching caused by agglomeration due to increased dopant concentration, and to prepare rare earth polymer composites with excellent dispersion, compatibility, transparency, and fluorescence properties, bonded rare earth polymer composites can be used. Compared with traditional bonded rare earth polymers, bonded rare earth polymer composites prepared by reacting hydrogen atoms on active groups with isocyanate groups on isophorone-diisocyanate have more controllable structure and properties. Moreover, due to the presence of a network structure, rare earth ions are effectively fixed within the grid, avoiding the displacement, dissociation, and agglomeration of small molecule ligands. As a result, the rare earth content in the composite is high, allowing the rare earth properties of the composite to be fully utilized.

[0004] The present invention combines two green technologies, ultraviolet light curing technology and water-based environmentally friendly materials, introduces rare earth compounds into environmentally friendly technology, and proposes a preparation method for a bonded rare earth modified water-based polyurethane acrylate coating. The method can solve the problems of uneven mixing of rare earth elements in polymer materials, poor stability, and difficult processing, and endows the light-curing material with unique rare earth properties. The material can be used in luminous coatings, inks and other fields, and has important practical significance for the development of radiation curing technology. Summary of the Invention

[0005] In view of the problems existing in the above-mentioned doped rare earth polymer composite materials, the object of the present invention is to provide a method for preparing a bonded rare earth modified waterborne polyurethane acrylate coating.

[0006] The present invention discloses a method for preparing a bonded rare earth modified waterborne polyurethane acrylate coating. The method comprises the following steps: using europium oxide, 2,2-dihydroxymethylpropionic acid (DMPA), and dibenzoylmethane (DBM) as raw materials to prepare a hydroxyl-containing rare earth complex (Eu(DMPA)3•DBM), which is then reacted with isophorone diisocyanate (IPDI), polyethylene glycol (PEG400), 2,2-dihydroxymethylpropionic acid (DMPA), and hydroxyethyl acrylate (HEA) to obtain a prepolymer emulsion; and then subjecting the prepolymer to ultraviolet light curing to obtain the bonded rare earth modified waterborne polyurethane acrylate coating. The specific process is as follows:

[0007] Step 1: Preparation of rare earth complexes

[0008] Add europium oxide (Eu2O3) to hydrochloric acid, heat and stir until the europium oxide is completely dissolved, and continue heating until the reaction solution is completely evaporated to obtain white powdery europium chloride (EuCl3). After cooling, add anhydrous ethanol to dissolve it to obtain an anhydrous ethanol solution of europium chloride for use;

[0009] A mixture of 2,2-dihydroxymethylpropionic acid (DMPA) and ethanol was stirred and heated to 70°C, and then sodium hydroxide solution was added to adjust the pH to 7. Subsequently, an anhydrous ethanol solution of europium chloride was added dropwise. After the addition was complete, dibenzoylmethane (DBM) was added dropwise. The mixture was stirred for another 4 hours before the reaction was terminated. After 24 hours of static precipitation, the product was filtered and vacuum dried to obtain a hydroxyl-containing rare earth complex (Eu(DMPA)3•DBM).

[0010] Step 2: Preparation of prepolymer emulsion

[0011] Polyethylene glycol (PEG400) and catalyst dibutyltin dilaurate (DBTL) were added dropwise to isophorone diisocyanate (IPDI) at 50°C with stirring. The mixture was stirred for 2 hours and then heated to 60°C. N-vinylpyrrolidone (NVP) solution of the rare earth complex was then added dropwise. The mixture was stirred and reacted for another 2 hours. Inhibitors p-hydroxyanisole (MEHQ) and hydroxyethyl acrylate (HEA) were then added dropwise. After 4 hours of reaction, the mixture was cooled to room temperature. Triethylamine was then added and stirred rapidly until the reaction was complete. Water was then added dropwise to fully emulsify the reaction product to obtain a prepolymer emulsion.

[0012] Step 3: Preparation of bonded rare earth modified waterborne polyurethane acrylate coating

[0013] A photoinitiator in an amount of 5% by mass is added to the prepolymer emulsion, stirred and dissolved, and then evenly applied to form a film, which is then cured by ultraviolet light to obtain a bonded rare earth modified waterborne polyurethane acrylate coating.

[0014] The molar ratio of europium oxide, 2,2-dimethylolpropionic acid and dibenzoylmethane is 1:3:1; the molar ratio of isophorone diisocyanate, polyethylene glycol, 2,2-dimethylolpropionic acid and hydroxyethyl acrylate is 1:1:1:1.

[0015] The photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173).

[0016] Beneficial effects of the present invention: The rare earth modified waterborne polyurethane acrylate coating of the present invention has good compatibility with waterborne polyurethane acrylate due to the presence of a bonded rare earth complex. The prepolymer emulsion only needs to be initiated by an initiator and cured by ultraviolet light. The resulting coating has good film-forming properties and stability. The preparation method is simple and easy to use. It is suitable for use in the fields of luminescent coatings, luminescent inks, medical materials, and the like of water-soluble photocurable systems. DETAILED DESCRIPTION

[0017] Example 1

[0018] Step 1: Preparation of rare earth complexes

[0019] (1) Weigh 1 mmol (0.352 g) of Eu2O3 into a beaker, add 10 ml of hydrochloric acid, and heat with a constant temperature magnetic stirrer until the Eu2O3 is completely dissolved. Continue heating until the solution is completely evaporated to obtain a white powdery solid EuCl3. After cooling, add 5 ml of anhydrous ethanol to dissolve it to obtain an anhydrous ethanol solution of EuCl3 for later use.

[0020] (2) Place the three-necked flask equipped with a thermometer and a condenser on a constant temperature heating magnetic stirrer.

[0021] (3) Weigh 6 mmol (0.804 g) of DMPA and 5 ml of ethanol (for dissolution) into a three-necked flask, add a stirrer, adjust the temperature to 70°C and stir.

[0022] (4) After complete dissolution, add 6 ml of sodium hydroxide solution and adjust the pH to 7.

[0023] (5) Use a rubber-tipped dropper to add the EuCl3 anhydrous ethanol solution. After the addition is complete, measure the pH value and adjust the pH value to 7. Weigh 4 mmol (0.896 g) of DBM and dissolve it in ethanol. After the system reacts for 1 hour, add the dissolved DBM and adjust the pH value of the system to 7.

[0024] (6) After continuing the reaction for 4 hours, the constant temperature heating magnetic stirrer was turned off and the mixture was allowed to stand overnight to allow the precipitate to completely settle out. The mixture was then filtered and rinsed with deionized water and anhydrous ethanol. Finally, the product was vacuum dried to a constant weight to obtain a rare earth complex.

[0025] Step 2: Preparation of prepolymer emulsion

[0026] (1) Assemble the stirrer, thermometer, constant pressure funnel, condenser, and four-necked flask, add 22.2 g of IPDI (isophorone diisocyanate) into the four-necked flask, and add 40 g of PEG400 (polyethylene glycol) and catalyst DBTL (dibutyltin dilaurate) into the constant pressure funnel while stirring at 50 °C, adding it dropwise at a rate of about one drop every three seconds.

[0027] (2) The concentration of isocyanate (-NCO) in the reaction system was measured every hour until the amount of -NCO in the system was consumed to the specified value. Then, 13.4 g of DMPA (2,2-dihydroxymethylpropionic acid) and the rare earth complex dissolved in 10 ml of NVP (N-vinylpyrrolidone) were added under stirring, and the temperature was raised to 60 °C.

[0028] (3) After 2 hours of reaction, add 0.1% of the polymerization inhibitor MEHQ (p-hydroxyanisole) and 11.6g of hydroxyethyl acrylate (HEA) under stirring, and continue to measure the concentration of -NCO in the reaction system every 1 hour. When the concentration of -NCO in the system is consumed by 98%, cool the device to room temperature, add 10.1g of triethylamine and stir rapidly. After sufficient reaction, keep stirring and add 10ml of water. After sufficient emulsification, the prepolymer emulsion can be obtained.

[0029] Step 3: Preparation of bonded rare earth modified waterborne polyurethane acrylate coating

[0030] Weigh 1 g of prepolymer emulsion, add 0.05 g of photoinitiator 1173, and after the photoinitiator is completely dissolved, evenly apply it on the patch with a glass rod. Then prevent it from being irradiated in a UV curing device and cure it for 60 seconds to obtain a bonded rare earth modified water-based polyurethane acrylate coating.

[0031] Example 2

[0032] Step 1: Preparation of rare earth complexes

[0033] The specific method is the same as that of Example 1.

[0034] Step 2: Preparation of prepolymer emulsion

[0035] (1) Assemble the agitator, thermometer, constant pressure funnel, condenser, and four-necked flask, add 17.4 g of TDI (toluene diisocyanate) into the four-necked flask, and add 40 g of PEG400 (polyethylene glycol) and catalyst DBTL (dibutyltin dilaurate) into the constant pressure funnel while stirring at 50°C, adding it dropwise at a rate of about one drop every three seconds.

[0036] (2) After 2 hours of reaction, 13.4 ml of DMPA (2,2-dihydroxymethylpropionic acid) and a rare earth complex dissolved in 10 ml of NVP (N-vinylpyrrolidone) were added under stirring, and the temperature was raised to 60°C.

[0037] (3) After 2 hours of reaction, add 0.1% of the polymerization inhibitor MEHQ (p-hydroxyanisole) and hydroxyethyl acrylate (HEA) under stirring, and continue to measure the concentration of -NCO in the reaction system every hour. When the concentration of -NCO in the system is consumed by 98%, cool the device to room temperature, add 10.1g of triethylamine and stir rapidly. After sufficient reaction, keep stirring and add 10ml of water. After sufficient emulsification, the prepolymer emulsion can be obtained.

[0038] Step 3: Preparation of bonded rare earth modified waterborne polyurethane acrylate coating

[0039] Weigh 1 g of prepolymer emulsion, add 0.05 g of photoinitiator 1173, stir, and after the photoinitiator is completely dissolved, evenly apply it on a glass slide with a glass rod, then place it in a UV curing device for irradiation and cure for 60 seconds to obtain a bonded rare earth modified waterborne polyurethane acrylate coating.

Claims

1. A method for preparing a bonded rare earth modified waterborne polyurethane acrylate coating, characterized in that: The preparation method uses europium oxide, 2,2-dimethylolpropionic acid, and dibenzoylmethane as raw materials to prepare a hydroxyl-containing rare earth complex, which is then reacted with isophorone diisocyanate, polyethylene glycol, 2,2-dimethylolpropionic acid, and hydroxyethyl acrylate to obtain a prepolymer emulsion, which is then cured by ultraviolet light to obtain a bonded rare earth-modified waterborne polyurethane acrylate coating. The specific process is as follows: Step 1: Preparation of rare earth complexes Add europium oxide to hydrochloric acid, heat and stir until europium oxide is completely dissolved, continue heating until the reaction solution is completely evaporated to obtain white powdery europium chloride, and then add anhydrous ethanol to dissolve it to obtain an anhydrous ethanol solution of europium chloride for use; After stirring and heating the mixture of 2,2-dimethylolpropionic acid and ethanol to 70°C, sodium hydroxide solution was added to adjust the pH to 7, and then anhydrous ethanol solution of europium chloride was added dropwise; after the addition was completed, dibenzoylmethane was added dropwise, and the reaction was stirred for another 4 hours before terminating the reaction. After standing for 24 hours to precipitate, the product was filtered and vacuum dried to obtain a hydroxyl-containing rare earth complex; Step 2: Preparation of prepolymer emulsion Polyethylene glycol and a catalyst, dibutyltin dilaurate, are added dropwise to isophorone diisocyanate under stirring at 50°C, and the mixture is stirred and reacted for 2 hours, then the temperature is raised to 60°C, and then a solution of a rare earth complex in N-vinyl pyrrolidone is added dropwise, and the stirring reaction is continued for 2 hours. Then, polymerization inhibitors, p-hydroxyanisole and hydroxyethyl acrylate, are added dropwise, and the mixture is cooled to room temperature after reacting for 4 hours. Triethylamine is then added and the mixture is stirred rapidly. After sufficient reaction, water is added dropwise to fully emulsify the reaction product to obtain a prepolymer emulsion. Step 3: Preparation of bonded rare earth modified waterborne polyurethane acrylate coating A photoinitiator in an amount of 5% by mass is added to the prepolymer emulsion, stirred and dissolved, and then evenly applied to form a film, which is then cured by ultraviolet light to obtain a bonded rare earth modified waterborne polyurethane acrylate coating.

2. The method for preparing a bonded rare earth modified waterborne polyurethane acrylate coating according to claim 1, characterized in that: The molar ratio of europium oxide, 2,2-dimethylolpropionic acid and dibenzoylmethane is 1:3:1; the molar ratio of isophorone diisocyanate, polyethylene glycol, 2,2-dimethylolpropionic acid and hydroxyethyl acrylate is 1:1:1:

1.

3. The method for preparing a bonded rare earth modified waterborne polyurethane acrylate coating according to claim 1, characterized in that: The photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone.