Aqueous polyurethane-acrylate emulsion and preparation method thereof

Abstract

The present invention discloses a waterborne polyurethane-acrylate emulsion and a preparation method thereof. The emulsion contains ethylenically unsaturated groups, ketone groups and hydrazide groups at the same time. The ethylenically unsaturated groups will produce crosslinks between or within the molecular chains under the action of ultraviolet light. At the same time, the ketone groups and hydrazide groups can produce crosslinks between or within the molecular chains as the pH value decreases during film formation and drying. The double crosslinking effect enables the paint film to have higher hardness, better wear resistance and excellent water boiling resistance; the pyridine ring is introduced into the resin molecular structure through ketone-hydrazide crosslinking, so that the comprehensive performance of the paint film is more excellent; a molecular weight regulator containing an ethylenically unsaturated group and having a tertiary amine structure is used to replace monohydroxy acrylate, which solves the problem of poor emulsion stability caused by hydrolysis of acrylates in current UV emulsions and greatly improves its hydrolytic stability. It is suitable for wood coatings, plastic coatings, and furniture coatings.

Description

Technical Field

[0001] The present invention belongs to the field of water-based UV, and in particular relates to a water-based polyurethane-acrylate emulsion with dual curing effect, a preparation method and an application thereof. Background Art

[0002] Traditional UV coatings typically consist primarily of oligomers, a large number of reactive diluent monomers, photoinitiators, and functional additives. These diluent monomers have a low molecular weight, are highly irritating, have a strong odor, and are somewhat allergenic, posing a risk to humans. Volatile reactive monomers released during application can also severely damage ecosystems. With growing environmental awareness, countries around the world have enacted strict laws and regulations to limit VOC emissions. Consequently, the shift from oil-based to water-based coatings is becoming increasingly common. In recent years, water-based UV coatings have experienced rapid growth due to their low toxicity, safety, environmental friendliness, ease of application, and superior performance.

[0003] Currently, common water-based UV coatings on the market are usually carboxylate systems, which are made by self-emulsification of macromolecular polymers containing acryloyloxy or methacryloyloxy groups with a certain degree of hydrophilicity, or by emulsifying a small amount of reactive monomers with a highly hydrophilic macromolecular polymer containing acryloyloxy or methacryloyloxy groups, with a large amount of water as the dispersion medium. To achieve sufficient cross-linking density, macromolecular polymers containing ethylenically unsaturated groups are usually end-capped with monohydroxy compounds with multiple ethylenically unsaturated groups, such as pentaerythritol triacrylate or di-trimethylolpropane triacrylate. Currently, such products generally suffer from poor stability. The main reason is that the polyurethane acrylate molecular chain contains a large number of acryloyloxy or methacryloyloxy groups, which easily migrate to the hydration layer. The ester bond is easily hydrolyzed in alkaline aqueous solution to release free acrylic acid. The acrylic acid competes with the alkaline compounds that neutralize 2,2-dimethylolpropionic acid or 2,2-dimethylolbutyric acid, resulting in a poor emulsification ability of the macromolecular polymer and precipitation or stratification of the emulsion.

[0004] CN202110013495.1 provides an aqueous polyurethane acrylate emulsion prepared using acrylated epoxidized soybean oil and pentaerythritol triacrylate. The resin film prepared therefrom has significantly improved hardness and strength, but its hydrolysis stability is poor.

[0005] CN200910000809.3 uses a dihydroxy chain extender containing an active double bond and a monohydroxy end-capping agent to prepare a new polyurethane acrylate dispersion. The paint film has high hardness and excellent wear resistance, and is particularly suitable for ABS plastic substrates. However, the dispersion prepared by this method has high viscosity, the solvent is not removed, and the hydrolysis stability is still not excellent.

[0006] CN201910343602.X provides a method for preparing polyurethane-modified epoxy acrylate. The method involves first preparing acrylate using an acrylic ring-opening epoxy resin, then grafting a hydrophilic compound onto the epoxy side chains via a reaction between a polyisocyanate and a hydroxyl group, and finally neutralizing and dispersing the acrylate with a concentrated alkali solution. The dispersion prepared by this method exhibits high hardness and excellent RCA wear resistance after UV curing, but the product suffers from high viscosity, the inability to remove the solvent, and a brittle film.

[0007] CN201180011756.0 provides a method for preparing a water-based polyurethane acrylate dispersion by reacting an unsaturated oil polyester with an epoxy acrylate. The dispersion prepared by this method exhibits excellent chemical resistance on wood after radiation curing and oxidative curing, but has poor adhesion to plastic substrates, and oxidative curing requires a long time.

[0008] CN201680054124.5 uses polycarbonate polyol as a soft segment to prepare a polyurethane acrylate dispersion, which solves the problem that polyester polyol as a soft segment is easily hydrolyzed, resulting in a decrease in paint film performance. However, it does not solve the problem that acrylate hydrolysis under alkaline conditions leads to a decrease in emulsion stability.

[0009] CN201910892108.9 simultaneously introduces ketone and hydrazide groups into the polyurethane-urea molecular chain, forming intra- and inter-molecular crosslinks during the film-forming process. It exhibits excellent solvent resistance and alcohol abrasion resistance on wood, but its adhesion performance on plastic substrates is poor, and its hardness and RCA wear resistance are much lower than those of ordinary UV products.

[0010] CN201911070180.X provides a method for improving the storage stability of polyurethane-urea dispersions. By using a special chain extender to introduce a tertiary amine structure into the polyurethane-urea molecular chain, the tertiary amine can neutralize the carboxyl groups generated by the hydrolysis of the polyester chain segments, maintaining the pH value of the system near neutral for a long time, and significantly improving the storage stability of the polyurethane-urea dispersion. However, this method is more suitable for the preparation of polyurethane-urea dispersions in the adhesive field. In the plastic paint field, the hardness, chemical resistance, and RCA wear resistance are all poor. Summary of the Invention

[0011] The primary objective of the present invention is to provide a waterborne polyurethane-acrylate emulsion with a dual-cure effect, characterized by the following features: (a) containing ethylenically unsaturated groups, ketone groups, and hydrazide groups. The ethylenically unsaturated groups produce inter- or intra-molecular crosslinks under ultraviolet light. Furthermore, the ketone and hydrazide groups can further crosslink with decreasing pH during film formation and drying. This dual crosslinking effect imparts high hardness, good abrasion resistance, and excellent water boiling resistance to the paint film. (b) Ketone-hydrazide crosslinking introduces pyridine rings into the resin molecular structure, further enhancing the overall performance of the paint film. (c) A molecular weight regulator containing an ethylenically unsaturated group and a tertiary amine structure is used instead of monohydroxy acrylate, addressing the problem of poor emulsion stability caused by hydrolysis of acrylates in current UV emulsions and significantly improving their hydrolytic stability. The emulsion exhibits excellent adhesion, RCA abrasion resistance, and water boiling resistance on PC and PC / ABS composite substrates.

[0012] Another object of the present invention is to provide a method for preparing the aqueous polyurethane-acrylate emulsion;

[0013] Another object of the present invention is to provide an application of the aqueous polyurethane-acrylate emulsion;

[0014] In order to achieve the above object of the invention, the present invention is implemented through the following technical solutions:

[0015] A waterborne polyurethane-acrylate emulsion with dual curing effect is prepared by reacting raw materials comprising the following components:

[0016] S1, one or more polyisocyanates;

[0017] S2, one or more macromolecular polyols having an average molecular weight of 500-5000 g / mol, preferably 500-1500 g / mol, more preferably 1000 g / mol;

[0018] S3, one or more compounds containing ethylenically unsaturated groups, which contain at least two groups capable of reacting with isocyanate;

[0019] S4, one or more ketone-containing compounds containing at least one group capable of reacting with an isocyanate;

[0020] Optional S5, one or more small molecule chain extenders containing at least two groups reactive with isocyanate and having a molecular weight of 60-499 g / mol;

[0021] Optional S6, one or more polyamine small molecule chain extenders containing active hydrogen, having a molecular weight of 60-499 g / mol;

[0022] S7, one or more hydrophilic or potentially hydrophilic compounds containing at least one group reactive with isocyanate;

[0023] S8, one or more pyridine hydrazide compounds, whose structural formula is as follows:

[0024]

[0025] Wherein, the X substituent may be a hydrazide group, a hydrazine group, an amino group or an aminoalkyl group, and its position may be at position 3, 4, 5 or 6, more preferably at position 3 or 6;

[0026] S9, one or more molecular weight regulators containing ethylenically unsaturated groups and having a tertiary amine structure, each containing at least one amino group capable of reacting with isocyanate;

[0027] Optional S10, one or more neutralizing agents;

[0028] S11, water;

[0029] Optional S12, a catalyst capable of catalyzing the reaction of isocyanate groups with hydroxyl groups;

[0030] S13, an organic solvent, which does not contain a group capable of reacting with an isocyanate;

[0031] S14, an active monomer having at least one acryloyloxy group or methacryloyloxy group on its molecular chain, preferably a compound having 2-6 acryloyloxy groups or methacryloyloxy groups on its molecular chain.

[0032] As a preferred embodiment, in the present invention, in the above-mentioned aqueous polyurethane-acrylate emulsion, based on the total mass of components S1-S11:

[0033] The amount of component S1 is 7.5-14.5wt%, preferably 9.3-12.6wt%;

[0034] The amount of component S2 is 3.5-10.0wt%, preferably 4.5-7.5wt%;

[0035] The amount of component S3 is 1.0-4.0wt%, preferably 2.1-3.0wt%;

[0036] The amount of component S4 is 0.1-2.2wt%, preferably 0.5-1.5wt%;

[0037] The amount of component S5 is 0.2-3.0wt%, preferably 0.45-1.1wt%;

[0038] The amount of component S6 is 0.2-2.5wt%, preferably 0.4-1.5wt%;

[0039] The amount of component S7 is 0.8-4.5wt%, preferably 1.4-2.5wt%;

[0040] The amount of component S8 is 0.2-2.0wt%, preferably 0.5-1.2wt%;

[0041] The amount of component S9 is 0.3-2.0wt%, preferably 0.5-1.1wt%;

[0042] The amount of component S10 is 0.3-2.0wt%, preferably 0.8-1.6wt%;

[0043] The amount of component S11 is 55-83 wt%, preferably 67.5-78 wt%.

[0044] In the present invention, in the above aqueous polyurethane-acrylate emulsion, based on the total mass of components S1-S5 and S7:

[0045] The dosage of the component S12 is 0-2000ppm, preferably 400-800ppm;

[0046] The dosage of the component S13 is 0.8-2.5 times, preferably 1.5-2.1 times.

[0047] In the present invention, in the above aqueous polyurethane-acrylate emulsion, based on the total mass of components S1-S10, the amount of component S14 is 0-2 times, preferably 0.45-0.9 times.

[0048] In the component S1 of the present invention, the polyisocyanate includes but is not limited to one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate and dicyclohexylmethane diisocyanate, preferably one or more of isophorone diisocyanate, hexamethylene diisocyanate and dicyclohexylmethane diisocyanate.

[0049] In component S2 of the present invention, the macromolecular polyol includes but is not limited to polyethylene glycol, polypropylene glycol, polyethylene glycol-propylene glycol, polytetramethylene glycol, polycaprolactone diol, polycarbonate diol, polyethylene adipate diol, polybutylene adipate diol, polyneopentyl adipate diol, polyhexanediol adipate diol, polyneopentyl adipate diol, one or more of polytetramethylene glycol and / or polycaprolactone diol, preferably polytetramethylene glycol and / or polycaprolactone diol.

[0050] In the component S3 of the present invention, the compound containing an ethylenically unsaturated group includes but is not limited to epoxy acrylate, epoxy methacrylate, pentaerythritol diacrylate, pentaerythritol dimethacrylate, preferably epoxy acrylate.

[0051] In component S4 of the present invention, the ketone-containing compound includes but is not limited to one or more of dihydroxyacetone, 3-[di-(2-hydroxyethyl)]amino-N-(1,1-dimethyl-3-butanone)propionamide, 3-[di-(2-hydroxypropyl)]amino-N-(1,1-dimethyl-3-butanone)propionamide, and 3-[tris(hydroxymethyl)]amino-N(1,1-dimethyl-3-butanone)acrylamide, preferably dihydroxyacetone and / or 3-[tris(hydroxymethyl)]amino-N(1,1-dimethyl-3-butanone)propionamide.

[0052] The 3-[bis-(2-hydroxyethyl)]amino-N(1,1-dimethyl-3-butanone)propionamide, 3-[bis-(2-hydroxypropyl)]amino-N(1,1-dimethyl-3-butanone)propionamide, and 3-[tris(hydroxymethyl)]amino-N(1,1-dimethyl-3-butanone)propionamide have the following structural formulas:

[0053]

[0054] In the component S5 of the present invention, the small molecule chain extender includes but is not limited to one or more of 1,3-propylene glycol, 1,4-butanediol, diethylene glycol, neopentyl glycol, 1,6-hexanediol, and 1,4-cyclohexanedimethanol, preferably neopentyl glycol.

[0055] In component S6 of the present invention, the polyamine small molecule chain extender containing active hydrogen includes but is not limited to one or more of ethylenediamine, hexamethylenediamine, pentamethylenediamine, diethylenetriamine, isophoronediamine and 4,4-diphenylmethanediamine, preferably ethylenediamine and / or isophoronediamine.

[0056] In component S7 of the present invention, the hydrophilic or hydrophilic potential compound includes but is not limited to one or more of 3-hydroxypropionic acid, dimethylolpropionic acid, dimethylolbutanoic acid, dimethylolacetic acid, trihydroxysulfonic acid, and dihydroxysuccinic acid, preferably dimethylolpropionic acid; optionally, the hydrophilic or hydrophilic potential compound further includes one or more non-ionic compounds, and the non-ionic compounds include but are not limited to monohydric alcohols and / or dihydric alcohols containing polyethylene oxide segments in the main chain and / or side chain, having a molecular weight of 500-3000 g / mol.

[0057] In component S8 of the present invention, the pyridine hydrazide compound includes but is not limited to pyridine-2,6-dicarboxylic acid hydrazide, pyridine-2,5-dicarboxylic acid hydrazide, 6-(hydrazino)pyridine-2-carboxylic acid hydrazide, 6-(aminoethyl)pyridine-2-carboxylic acid hydrazide, 6-(aminomethyl)pyridine-2-carboxylic acid hydrazide, 3-(amino)pyridine-2-carboxylic acid hydrazide, 6-(amino)pyridine-2-carboxylic acid hydrazide, preferably pyridine-2,6-dicarboxylic acid hydrazide and / or 3-(amino)pyridine-2-carboxylic acid hydrazide.

[0058] Component S9 of the present invention includes but is not limited to 2-(piperazine)ethyl acrylate, 1-allylpiperazine, 1-cyclohexyl-3-enylmethylpiperazine, 2-(piperazine)ethyl methacrylate, and 1-piperazine-3-cyclopentenone, preferably 2-(piperazine)ethyl acrylate.

[0059] In the component S10 of the present invention, the neutralizing agent includes but is not limited to one or more of triethanolamine, triethylamine, sodium hydroxide and N,N-dimethylethanolamine, preferably triethylamine.

[0060] In the component S12 of the present invention, the catalyst includes but is not limited to an organic bismuth or organic tin catalyst, preferably Bi@8108 or butyltin laurate from a leading American company, more preferably Bi@8108 from a leading American company.

[0061] In the component S13 of the present invention, the organic solvent is a low-boiling-point organic solvent with a boiling point of 40-85° C., including but not limited to acetone and butanone, preferably acetone.

[0062] In the component S14 of the present invention, the active monomers include but are not limited to hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, ethoxylated trimethylolpropane triacrylate TMPTA (3EO) / TMPTA (9EO) / TMPTA (15EO), optimized trimethylolpropane triacrylate and dipentaerythritol hexaacrylate.

[0063] In the present invention, the solid content of the aqueous polyurethane-acrylate emulsion with dual curing effect is preferably 25-55wt%, more preferably 35-45wt%; the average particle size of the solid content is preferably in the range of 50-500nm, more preferably in the range of 100-250nm.

[0064] In another aspect of the present invention, a method for preparing the aqueous polyurethane-acrylate emulsion having a dual curing effect is provided, comprising the following steps:

[0065] (1) Component S1, component S2, component S3, component S4, component S5, component S7, component S12, and component S13 are mixed and reacted at 70-85° C. until the NCO content reaches the theoretical value to form a diisocyanate-terminated prepolymer;

[0066] (2) cooling the prepolymer obtained in step (1) to 30-60°C, adding S9 and continuing the reaction for 10-60 minutes, then adding the remaining component S13, controlling the temperature to 30-45°C, adding component S10 and reacting for 5-10 minutes to obtain a neutralized prepolymer dilution;

[0067] (3) uniformly mixing component S14 with the prepolymer dilution obtained in step (2), and then adding component S11 for shear dispersion to obtain a coarse emulsion;

[0068] (4) Adding component S8 and component S6 to the crude emulsion of step (3), carrying out chain extension reaction at 20-45° C. for 5-15 min, and removing the solvent to obtain an aqueous polyurethane acrylate emulsion.

[0069] In step (1) and step (2) of the present invention, the mass ratio of component S13 added is 1:(4-10).

[0070] In step (3) of the present invention, the pH of the obtained crude emulsion is greater than 7.

[0071] In step (4) of the present invention, the components S8 and S6 are prepared in aqueous solution, and the amount of water used is 3-6 times the sum of the masses of components S8 and S6. The amount of water used is included in the total mass of component S11, that is, the sum of the mass of the water contained in the aqueous solution and the component S11 added in step (3) is the amount of raw material component S11.

[0072] In step (4) of the present invention, the solvent removal condition is reduced pressure distillation, and the solvent, namely component S13, is preferably completely removed.

[0073] The beneficial effects of the present invention are mainly reflected in the following aspects:

[0074] (1) The present invention is different from the general waterborne polyurethane-acrylate emulsion. It has a dual curing effect. The highly active ethylenically unsaturated groups produce inter-molecular or intra-molecular crosslinking under the action of ultraviolet light. The ketone group and the hydrazide group can produce inter-molecular or intra-molecular crosslinking as the pH value decreases during the film formation and drying process. The dual crosslinking effect makes the paint film have higher hardness, better wear resistance, and excellent water boiling resistance.

[0075] (2) The present invention is different from the general water-based polyurethane-acrylate emulsion. It uses a molecular weight regulator containing an ethylenically unsaturated group and a tertiary amine structure to replace the monohydroxy acrylate, which solves the problem of emulsion stratification caused by the hydrolysis of acrylate in the current UV emulsion and greatly improves its hydrolysis stability.

[0076] (3) The present invention is different from the general ketone hydrazine cross-linking. It uses pyridine hydrazide compounds instead of ordinary hydrazide compounds, introduces the pyridine ring into the resin molecular structure, and makes the comprehensive performance of the paint film more excellent. DETAILED DESCRIPTION

[0077] The following examples are provided to further illustrate the present invention, rather than to limit the scope of the present invention. It should be understood by those skilled in the art that the technical solution of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solution of the present invention, and all should be encompassed within the scope of the claims of the present invention. Within the scope of the present invention, the above-mentioned various technical features of the present invention and the various technical features specifically described below (such as in the examples) can be combined with each other to form new or preferred technical solutions.

[0078] Main raw material sources of the embodiments:

[0079] Polytetramethylenetetramethylene ether glycol: technical grade, functionality 2, molecular weight 1000 g / mol, BASF GmbH;

[0080] Catalyst: Bi@8108, industrial grade, Leading Co., Ltd., USA;

[0081] Dimethylolpropionic acid (DMPA): technical grade, Perstorp Chemical Company;

[0082] Neopentyl glycol: industrial grade, Wanhua Chemical Group Co., Ltd.

[0083] Dihydroxyacetone: analytical grade, Sinopharm Chemical Reagent Co., Ltd.

[0084] Epoxy acrylate (6104): industrial grade, Jiangsu Sanmu Chemical;

[0085] Acetone: industrial grade, Wanhua Chemical Group Co., Ltd.

[0086] Polycaprolactone diol, technical grade, functionality 2, molecular weight 100 g / mol, Perstorp Chemical Company;

[0087] 4,4-Dicyclohexylmethane diisocyanate (HMDI): industrial grade, Wanhua Chemical Group Co., Ltd.

[0088] Isophorone diisocyanate: industrial grade, Wanhua Chemical Group Co., Ltd.

[0089] Hexamethylene diisocyanate: industrial grade, Wanhua Chemical Group Co., Ltd.

[0090] 2-(Piperazine)ethyl acrylate: technical grade, CHEMSTEP;

[0091] 1-Allylpiperazine: industrial grade, Shanghai Mairui Chemical Technology Co., Ltd.;

[0092] 3-[Tris(hydroxymethyl)]amino-N(1,1-dimethyl-3-butanone)propionamide: prepared by Michael addition reaction of hydroxymethylaminomethane and diacetone acrylamide;

[0093] Ethylenediamine: analytical grade, Sinopharm Chemical Reagent Co., Ltd.;

[0094] Isophorone diamine: industrial grade, Wanhua Chemical Group Co., Ltd.

[0095] Triethylamine: analytical grade, Sinopharm Chemical Reagent Co., Ltd.;

[0096] Pyridine-2,6-dicarboxylic acid hydrazide: industrial grade, Zhengzhou Aikemu Chemical Co., Ltd.

[0097] 3-(Amino)pyridine-2-carboxylic acid hydrazide: technical grade, CHEMSTEP;

[0098] Adipic acid dihydrazide (ADH): analytical grade, Sinopharm Chemical Reagent Co., Ltd.;

[0099] Polyethylene glycol monomethyl ether: industrial grade, molecular weight 1200 g / mol, Hannong Chemical Co., Ltd.

[0100] Ethoxylated trimethylolpropane triacrylate (TMPTA-3EO): industrial grade, Double Bond Chemical Co., Ltd., Taiwan, China;

[0101] Trimethylolpropane triacrylate (TMPTA): industrial grade, Double Bond Chemical Co., Ltd., Taiwan, China;

[0102] Dipentaerythritol hexaacrylate: industrial grade, Double Bond Chemical Co., Ltd., Taiwan, China;

[0103] Pentaerythritol triacrylate: industrial grade, Double Bond Chemical Co., Ltd., Taiwan, China.

[0104] Analytical instruments and test methods:

[0105] Pendulum hardness test method: TQC pendulum hardness tester, SPO500;

[0106] Solid content test method: take an appropriate amount of emulsion in a container made of tin foil, weigh the weight change before and after 125℃ for 30 minutes, and calculate its solid content;

[0107] Particle size test method: Malvern particle size analyzer;

[0108] Adhesion: Tested by cross-hatch method;

[0109] Wear resistance test: tested using RCA paper tape wear tester;

[0110] Boiling resistance test: The substrate with the paint film is placed in an 80℃ water bath and boiled for 6 hours. The changes in adhesion and appearance of the paint film before and after are compared. The more severe the decrease in adhesion before and after boiling, the worse the boiling resistance of the paint film. The greater the change in appearance before and after boiling, the worse the boiling resistance of the paint film.

[0111] Example 1

[0112] To a four-necked flask equipped with a reflux condenser, a thermometer, and a mechanical stirrer were added 70.38 g of hexamethylene diisocyanate (HDI), 12.6 g of dimethylolpropionic acid, 7.38 g of neopentyl glycol, 21 g of epoxy acrylate 6104, 40.16 g of polycaprolactone diol (functionality 2, molecular weight 1000 g / mol), 4 g of polyethylene glycol monomethyl ether (functionality 1, molecular weight 1200 g / mol), 5.9 g of dihydroxyacetone, 45.20 g of acetone, and 0.06 g of Bi@8108. The mixture was reacted at 75° C. During the experiment, NCO content was sampled and monitored until it reached the theoretical value of 4.37%, thereby producing a diisocyanate-terminated prepolymer.

[0113] The temperature was lowered to 45° C., 5.90 g of 2-(piperazine)ethyl acrylate was added and the mixture was reacted for 30 minutes. Then 242.13 g of acetone was added and stirred for 5 minutes. The temperature was lowered to 35° C., 9.50 g of triethylamine was added and the mixture was reacted for 5 minutes.

[0114] After the neutralization reaction was completed, 72.75 g of dipentaerythritol hexaacrylate (DPHA) and 72.75 g of trimethylolpropane triacrylate (TMPTA) were added and mixed under high shear dispersion conditions for 5 min, and then 499.19 g of deionized water was added to obtain an emulsion with a pH value of 8.05;

[0115] Finally, a mixed solution of 10.30 g of isophorone diamine, 4.27 g of pyridine-2,6-dicarboxylic acid hydrazide and 58.26 g of water was added and reacted at 35°C for 10 min to obtain a crude emulsion. The crude emulsion was distilled under reduced pressure to remove acetone to obtain an aqueous polyurethane-acrylate emulsion I with a solid content of 37% and a particle size of 198 nm having a dual curing effect.

[0116] Example 2

[0117] To a four-necked flask equipped with a reflux condenser, a thermometer, and a mechanical stirrer were added 109.76 g of 4,4'-dicyclohexylmethane diisocyanate (HMDI), 12.6 g of dimethylolpropionic acid, 7.38 g of neopentyl glycol, 21 g of epoxy acrylate 6104, 40.16 g of polytetramethylene glycol (functionality 2, molecular weight 1000 g / mol), 4 g of polyethylene glycol monomethyl ether (functionality 1, molecular weight 1200 g / mol), 5.9 g of dihydroxyacetone, 56.22 g of acetone, and 0.08 g of Bi@8108. The mixture was reacted at 75°C. During the experiment, NCO was sampled and monitored until the NCO content reached the theoretical value of 3.51%, thereby generating a diisocyanate-terminated prepolymer.

[0118] The temperature was lowered to 45° C., 5.4 g of 2-(piperazine)ethyl acrylate was added and the mixture was reacted for 40 min. Then 301.2 g of acetone was added and stirred for 5 min. The temperature was lowered to 35° C., 9.50 g of triethylamine was added and the mixture was reacted for 5 min.

[0119] After the neutralization reaction was completed, 86.14 g of dipentaerythritol hexaacrylate (DPHA) and 86.14 g of ethoxylated trimethylolpropane triacrylate (TMPTA-3EO) were added and mixed under high shear dispersion conditions for 5 min, and then 623.41 g of deionized water was added to obtain an emulsion with a pH value of 7.89;

[0120] Finally, a mixed solution of 3.46 g of ethylenediamine, 5.70 g of 3-(amino)pyridine-2-carboxylic acid hydrazide and 36.64 g of water was added and reacted at 35°C for 10 min to obtain a crude emulsion. The crude emulsion was distilled under reduced pressure to remove acetone to obtain an aqueous polyurethane-acrylate emulsion II with a solid content of 37% and a particle size of 214 nm having a dual curing effect.

[0121] Example 3

[0122] To a four-necked flask equipped with a reflux condenser, a thermometer, and a mechanical stirrer were added 70.38 g of hexamethylene diisocyanate HDI, 13.4 g of dimethylolpropionic acid, 6.8 g of neopentyl glycol, 19 g of epoxy acrylate 6104, 53.28 g of polycaprolactone diol (functionality 2, molecular weight 1000 g / mol), 2.4 g of polyethylene glycol monomethyl ether (functionality 1, molecular weight 1200 g / mol), 10.14 g of 3-[tris(hydroxymethyl)]amino-N-(1,1-dimethyl-3-butanone)propionamide, 49.11 g of acetone, and 0.07 g of Bi@8108. The mixture was reacted at 75° C. During the experiment, NCO was sampled and monitored until the NCO content reached the theoretical value of 4.17%, thereby producing a diisocyanate-terminated prepolymer.

[0123] The temperature was lowered to 50°C, 4.2 g of 1-allylpiperazine was added and the mixture was reacted for 30 min, then 263.1 g of acetone was added and stirred for 5 min, and the temperature was lowered to 35°C, 10.1 g of triethylamine was added and the mixture was reacted for 5 min.

[0124] After the neutralization reaction was completed, 65.77 g of dipentaerythritol hexaacrylate (DPHA) and 65.77 g of ethoxylated trimethylolpropane triacrylate (TMPTA-3EO) were added and mixed under high shear dispersion conditions for 5 minutes, and then 489.11 g of deionized water was added to obtain an emulsion with a pH value of 8.11;

[0125] Finally, a mixed solution of 8.8 g of isophorone diamine, 8.9 g of pyridine-2,6-dicarboxylic acid hydrazide and 70.80 g of water was added and reacted at 35° C. for 10 min to obtain a crude emulsion. The crude emulsion was then distilled under reduced pressure to remove acetone to obtain an aqueous polyurethane-acrylate emulsion III with a solid content of 37% and a particle size of 182 nm having a dual-curing effect.

[0126] Example 4

[0127] To a four-necked flask equipped with a reflux condenser, a thermometer, and a mechanical stirrer were added 97.0 g of isophorone diisocyanate (IPDI), 13 g of dimethylolpropionic acid, 3.58 g of neopentyl glycol, 22 g of epoxy acrylate 6104, 40.16 g of polycaprolactone diol (functionality 2, molecular weight 1000 g / mol), 0.8 g of polyethylene glycol monomethyl ether (functionality 1, molecular weight 1200 g / mol), 7 g of dihydroxyacetone, 51.40 g of acetone, and 0.15 g of Bi@8108. The mixture was reacted at 75° C. During the experiment, samples were taken to monitor the NCO content until the NCO content reached the theoretical value of 5.23%, thereby producing a diisocyanate-terminated prepolymer.

[0128] The temperature was lowered to 45° C., 8.0 g of 2-(piperazine)ethyl acrylate was added and the mixture was reacted for 30 minutes. Then 275.31 g of acetone was added and stirred for 5 minutes. The temperature was lowered to 35° C., 9.80 g of triethylamine was added and the mixture was reacted for 5 minutes.

[0129] After the neutralization reaction was completed, 64.11 g of dipentaerythritol hexaacrylate (DPHA) and 64.11 g of ethoxylated trimethylolpropane triacrylate (TMPTA-3EO) were added and mixed under high shear dispersion conditions for 5 min, and then 521.61 g of deionized water was added to obtain an emulsion with a pH value of 7.92;

[0130] Finally, a mixed solution of 5.60 g of ethylenediamine, 4.34 g of pyridine-2,6-dicarboxylic acid hydrazide and 39.75 g of water was added and reacted at 35° C. for 10 min to obtain a crude emulsion. The crude emulsion was distilled under reduced pressure to remove acetone to obtain an aqueous polyurethane-acrylate emulsion IV with a solid content of 37% and a particle size of 209 nm having a dual curing effect.

[0131] Comparative Example 1

[0132] To a four-necked flask equipped with a reflux condenser, a thermometer, and a mechanical stirrer were added 87.0 g of isophorone diisocyanate (IPDI), 13.0 g of dimethylolpropionic acid, 3.58 g of neopentyl glycol, 22 g of epoxy acrylate 6104, 48 g of polycaprolactone diol (functionality 2, molecular weight 1000 g / mol), 0.8 g of polyethylene glycol monomethyl ether (functionality 1, molecular weight 1200 g / mol), 48.83 g of acetone, and 0.14 g of Bi@8108. The mixture was reacted at 75° C. During the experiment, samples were taken to monitor the NCO content until the NCO content reached the theoretical value of 6.44%, thereby producing a diisocyanate-terminated prepolymer.

[0133] The temperature was lowered to 40° C., 28 g of 2-(piperazine)ethyl acrylate was added and the mixture was reacted for 30 min. Then, 261.57 g of acetone was added and stirred for 5 min. The temperature was lowered to 35° C., 9.80 g of triethylamine was added and the mixture was reacted for 5 min.

[0134] After the neutralization reaction was completed, 65.79 g of dipentaerythritol hexaacrylate (DPHA) and 65.79 g of ethoxylated trimethylolpropane triacrylate (TMPTA-3EO) were added and mixed under high shear dispersion conditions for 5 minutes, and then 558.54 g of deionized water was added to obtain an emulsion with a pH value of 7.96;

[0135] Finally, a mixed solution of 4.4 g ethylenediamine and 17.6 g water was added and reacted at 35° C. for 10 min to obtain a crude emulsion, which was then distilled under reduced pressure to remove acetone to obtain an aqueous polyurethane-acrylate emulsion E1 with a solid content of 37% and a particle size of 224 nm.

[0136] Comparative Example 2

[0137] To a four-necked flask equipped with a reflux condenser, a thermometer, and a mechanical stirrer were added 87.0 g of isophorone diisocyanate (IPDI), 13.0 g of dimethylolpropionic acid, 3.58 g of neopentyl glycol, 22 g of epoxy acrylate 6104, 48 g of polycaprolactone diol (functionality 2, molecular weight 1000 g / mol), 0.8 g of polyethylene glycol monomethyl ether (functionality 1, molecular weight 1200 g / mol), 48.83 g of acetone, and 0.14 g of Bi@8108. The reaction was carried out at 75° C. During the experiment, samples were taken to monitor the NCO content until the NCO content reached the theoretical value of 6.44%. Then, 70.66 g of pentaerythritol triacrylate was added, and the temperature was raised to 80° C. and the reaction was continued until the NCO content reached 2.72%.

[0138] The temperature was lowered to 50°C, 261.57 g of acetone was added, and the mixture was stirred for 5 min. The temperature was then lowered to 35°C, 9.80 g of triethylamine was added, and the mixture was reacted for 5 min.

[0139] After the neutralization reaction was completed, 79.37 g of dipentaerythritol hexaacrylate (DPHA) and 79.37 g of ethoxylated trimethylolpropane triacrylate (TMPTA-3EO) were added and mixed under high shear dispersion conditions for 5 min, and then 677.34 g of deionized water was added to obtain an emulsion with a pH value of 7.89;

[0140] Finally, a mixed solution of 4.4 g ethylenediamine and 17.6 g water was added and reacted at 35° C. for 10 min to obtain a crude emulsion, which was then distilled under reduced pressure to remove acetone to obtain an aqueous polyurethane-acrylate emulsion E2 with a solid content of 37% and a particle size of 224 nm.

[0141] Comparative Example 3

[0142] To a four-necked flask equipped with a reflux condenser, a thermometer, and a mechanical stirrer were added 97.0 g of isophorone diisocyanate (IPDI), 13 g of dimethylolpropionic acid, 3.58 g of neopentyl glycol, 22 g of epoxy acrylate 6104, 40.16 g of polycaprolactone diol (functionality 2, molecular weight 1000 g / mol), 0.8 g of polyethylene glycol monomethyl ether (functionality 1, molecular weight 1200 g / mol), 7 g of dihydroxyacetone, 51.39 g of acetone, and 0.15 g of Bi@8108. The reaction was carried out at 75° C. During the experiment, samples were taken to monitor the NCO content until the NCO content reached the theoretical value of 5.23%. Then, 20.2 g of pentaerythritol triacrylate was added, and the temperature was raised to 80° C. and the reaction was continued until the NCO content reached 4.10%.

[0143] The temperature was lowered to 50°C, 275.31 g of acetone was added, and the mixture was stirred for 5 min. The temperature was then lowered to 35°C, 9.80 g of triethylamine was added, and the mixture was reacted for 5 min.

[0144] After the neutralization reaction was completed, 67.99 g of dipentaerythritol hexaacrylate (DPHA) and 67.99 g of ethoxylated trimethylolpropane triacrylate (TMPTA-3EO) were added and mixed under high shear dispersion conditions for 5 min, and then 555.61 g of deionized water was added to obtain an emulsion with a pH value of 7.91;

[0145] Finally, a mixed solution of 5.60 g of ethylenediamine, 4.34 g of pyridine-2,6-dicarboxylic acid hydrazide and 39.75 g of water was added and reacted at 35° C. for 10 min to obtain a crude emulsion. The crude emulsion was then distilled under reduced pressure to remove acetone to obtain an aqueous polyurethane-acrylate emulsion E3 with a solid content of 37% and a particle size of 209 nm having a dual-curing effect.

[0146] Comparative Example 4

[0147] To a four-necked flask equipped with a reflux condenser, a thermometer, and a mechanical stirrer were added 70.38 g of hexamethylene diisocyanate HDI, 12.6 g of dimethylol propionic acid, 7.38 g of neopentyl glycol, 21 g of epoxy acrylate 6104, 40.16 g of polycaprolactone diol (functionality 2, molecular weight 1000 g / mol), 4 g of polyethylene glycol monomethyl ether (functionality 1, molecular weight 1200 g / mol), 5.9 g of dihydroxyacetone, 45.20 g of acetone, and 0.06 g of Bi@8108. The mixture was reacted at 75° C. During the experiment, NCO was sampled and monitored until the NCO content reached a theoretical value of 4.37%, thereby generating a diisocyanate-terminated prepolymer.

[0148] The temperature was lowered to 45° C., 5.90 g of 2-(piperazine)ethyl acrylate was added and the mixture was reacted for 30 minutes. Then 242.13 g of acetone was added and stirred for 5 minutes. The temperature was lowered to 35° C., 9.50 g of triethylamine was added and the mixture was reacted for 5 minutes.

[0149] After the neutralization reaction was completed, 72.57 g of dipentaerythritol hexaacrylate (DPHA) and 72.57 g of trimethylolpropane triacrylate (TMPTA) were added and mixed under high shear dispersion conditions for 5 min, and then 499.62 g of deionized water was added to obtain an emulsion with a pH value of 8.05;

[0150] Finally, a mixed solution of 10.30 g of isophorone diamine, 3.81 g of adipic dihydrazide, and 56.43 g of water was added and reacted at 35° C. for 10 minutes to obtain a crude emulsion. The crude emulsion was then subjected to reduced pressure distillation to remove acetone, yielding a waterborne polyurethane-acrylate emulsion E4 with a solid content of 37% and a particle size of 192 nm and possessing a dual-cure effect.

[0151] Application example (plastic matte paint)

[0152] According to the weight ratio in Table 1, add each component in sequence with stirring at 600-800 rpm / min, and stir for 30-40 minutes until completely dispersed; apply a film on the PC board, level at room temperature for 1 minute, then bake at 60°C for 15 minutes, fully cure in a UV curing machine, and maintain at room temperature for 24 hours before performing performance testing. The results are shown in Table 2.

[0153] Table 1 Raw materials composition by weight

[0154]

[0155]

[0156] Table 2 Emulsion and paint film performance evaluation results

[0157] sample Pendulum hardness Adhesion RCA wear resistance Boiling resistance Emulsion thermal storage stability Application Example 1 118 5B 260 times 5 5 Application Example 2 116 5B 245 times 5 5 Application Example 3 117 5B 250 times 5 5 Application Example 4 115 5B 235 times 5 5 Comparative Application Example 1 98 4B 80 times 2 5 Comparative Application Example 2 108 4B 170 times 4 2 Comparative Application Example 3 113 5B 212 times 5 3 Comparative Application Example 4 105 4B 185 times 4 5

[0158] Note: The boiling resistance and heat storage stability of emulsions are rated on a 5-point scale, with 5 being the best and 1 being the worst.

Claims

1. An aqueous polyurethane-acrylate emulsion, which is prepared by reacting raw materials comprising the following components: S1, one or more polyisocyanates; S2, one or more macromolecular polyols having an average molecular weight of 500-5000 g / mol; S3, one or more compounds containing ethylenically unsaturated groups, which contain at least two groups capable of reacting with isocyanate; S4, one or more ketone-containing compounds containing at least one group capable of reacting with an isocyanate; Optional S5, one or more small molecule chain extenders containing at least two groups reactive with isocyanate and having a molecular weight of 60-499 g / mol; Optional S6, one or more polyamine small molecule chain extenders containing active hydrogen, having a molecular weight of 60-499 g / mol; S7, one or more hydrophilic or potentially hydrophilic compounds containing at least one group reactive with isocyanate; S8, one or more pyridine hydrazide compounds, whose structural formula is as follows: in, The X substituent is a hydrazide group, a hydrazine group, an amino group or an aminoalkyl group, and its position is 3, 4, 5 or 6; S9, one or more molecular weight regulators containing ethylenically unsaturated groups and having a tertiary amine structure, each containing at least one amino group capable of reacting with isocyanate; Optional S10, one or more neutralizing agents; S11, water; Optional S12, a catalyst capable of catalyzing the reaction of isocyanate groups with hydroxyl groups; S13, an organic solvent, which does not contain a group capable of reacting with an isocyanate; S14. An active monomer having at least one acryloyloxy group or methacryloyloxy group on its molecular chain.

2. The aqueous polyurethane-acrylate emulsion according to claim 1, characterized in that The average molecular weight of S2, one or more macromolecular polyols, is 500-1500 g / mol.

3. The aqueous polyurethane-acrylate emulsion according to claim 1, characterized in that The average molecular weight of the S2, one or more macromolecular polyols, is 1000 g / mol.

4. The aqueous polyurethane-acrylate emulsion according to claim 1, characterized in that The S14, active monomer, is a compound containing 2-6 acryloyloxy groups or methacryloyloxy groups on its molecular chain.

5. The aqueous polyurethane-acrylate emulsion according to claim 1, characterized in that Based on the total mass of components S1-S11: The amount of component S1 is 7.5-14.5wt%; The amount of component S2 is 3.5-10.0wt%; The amount of component S3 is 1.0-4.0wt%; The amount of component S4 is 0.1-2.2 wt%; The amount of component S5 is 0.2-3.0wt; The amount of component S6 is 0.2-2.5wt%; The amount of component S7 is 0.8-4.5wt%; The amount of component S8 is 0.2-2.0wt%; The amount of component S9 is 0.3-2.0wt%; The amount of component S10 is 0.3-2.0wt%; The amount of component S11 is 55-83 wt%.

6. The aqueous polyurethane-acrylate emulsion according to claim 1, characterized in that Based on the total mass of components S1-S11: The amount of component S1 is 9.3-12.6 wt%; The amount of component S2 is 4.5-7.5wt%; The amount of component S3 is 2.1-3.0wt%; The amount of component S4 is 0.5-1.5wt%; The amount of component S5 is 0.45-1.1wt%; The amount of component S6 is 0.4-1.5wt%; The amount of component S7 is 1.4-2.5wt%; The amount of component S8 is 0.5-1.2wt%; The amount of component S9 is 0.5-1.1 wt%; The amount of component S10 is 0.8-1.6 wt%; The amount of component S11 is 67.5-78 wt%.

7. The aqueous polyurethane-acrylate emulsion according to claim 1 or 5, characterized in that Based on the total mass of components S1-S5 and S7: the usage of component S12 is 0-2000 ppm; the usage of component S13 is 0.8-2.5 times.

8. The aqueous polyurethane-acrylate emulsion according to claim 1 or 5, characterized in that Based on the total mass of components S1-S5 and S7: the usage of component S12 is 400-800 ppm; the usage of component S13 is 1.5-2.1 times.

9. The aqueous polyurethane-acrylate emulsion according to claim 7, characterized in that Based on the total mass of components S1-S10: the usage of component S14 is 0.45-2 times.

10. The aqueous polyurethane-acrylate emulsion according to claim 9, characterized in that Based on the total mass of components S1-S10: the usage of component S14 is 0.45-0.9 times.

11. The aqueous polyurethane-acrylate emulsion according to claim 1, characterized in that: The component S3 is selected from one or more of epoxy acrylate, epoxy methacrylate, pentaerythritol diacrylate, and pentaerythritol dimethacrylate.

12. The aqueous polyurethane-acrylate emulsion according to claim 1, characterized in that The component S4 is selected from one or more of dihydroxyacetone, 3-[di-(2-hydroxyethyl)]amino-N-(1,1-dimethyl-3-butanone)propionamide, 3-[di-(2-hydroxypropyl)]amino-N-(1,1-dimethyl-3-butanone)propionamide, and 3-[tris(hydroxymethyl)]amino-N(1,1-dimethyl-3-butanone)acrylamide.

13. The aqueous polyurethane-acrylate emulsion according to claim 1, characterized in that The component S8 is selected from one or more of pyridine-2,6-dicarboxylic acid hydrazide, pyridine-2,5-dicarboxylic acid hydrazide, 6-(hydrazino)pyridine-2-carboxylic acid hydrazide, 6-(aminoethyl)pyridine-2-carboxylic acid hydrazide, 6-(aminomethyl)pyridine-2-carboxylic acid hydrazide, 3-(amino)pyridine-2-carboxylic acid hydrazide, and 6-(amino)pyridine-2-carboxylic acid hydrazide.

14. The aqueous polyurethane-acrylate emulsion according to claim 1, characterized in that The component S9 is selected from one or more of 2-(piperazine)ethyl acrylate, 1-allylpiperazine, 1-cyclohexyl-3-enylmethylpiperazine, 2-(piperazine)ethyl methacrylate, and 1-piperazine-3-cyclopentenone.

15. The aqueous polyurethane-acrylate emulsion according to claim 1, characterized in that The solid content of the aqueous polyurethane-acrylate emulsion is 25-55 wt %; the average particle size of the solid content is 50-500 nm.

16. The aqueous polyurethane-acrylate emulsion according to claim 1, characterized in that The solid content of the aqueous polyurethane-acrylate emulsion is 35-45 wt %; the average particle size of the solid content is 100-250 nm.

17. A method for preparing the aqueous polyurethane-acrylate emulsion according to any one of claims 1 to 16, characterized in that: The following steps are involved: (1) Component S1, component S2, component S3, component S4, component S5, component S7, component S12, and component S13 are mixed and reacted at 70-85° C. until the NCO content reaches the theoretical value to form a diisocyanate-terminated prepolymer; (2) cooling the prepolymer obtained in step (1) to 30-60°C, adding S9 and continuing the reaction for 10-60 minutes, then adding the remaining component S13, controlling the temperature to 30-45°C, adding component S10 and reacting for 5-10 minutes to obtain a neutralized prepolymer dilution; (3) uniformly mixing component S14 with the prepolymer dilution obtained in step (2), and then adding component S11 for shear dispersion to obtain a coarse emulsion; (4) Adding component S8 and component S6 to the crude emulsion of step (3), carrying out chain extension reaction at 20-45° C. for 5-15 min, and removing the solvent to obtain an aqueous polyurethane acrylate emulsion.

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