High adhesion water-based composite ink and preparation method thereof

Abstract

The application relates to the technical field of inks, and discloses a water-based composite ink with high adhesion and a preparation method thereof. The water-based polyurethane connecting material prepared as raw material of the water-based composite ink has excellent hydrophilicity and water solubility, which is beneficial to improving the storage stability of the ink. The polyurethane molecular chain contains a heat-resistant structure, which can improve the thermal stability of the polyurethane molecular chain. Since the polyurethane molecular chain has strong coordination interaction with the surface of a base material, the adhesion performance and adhesion of the polyurethane paint film to the surface of the base material are improved, the interfacial bonding strength of the ink to the surface of the base material is improved, and meanwhile, the heat-resistant structure introduced by the polyurethane molecular chain is beneficial to improving the thermal decomposition temperature and heat resistance of the ink paint film, ensuring the printing effect and maintainability of the ink, widening the application scenarios of the ink, and being suitable for printing in the fields of food packaging bags and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ink, in particular to a water-based composite ink with high adhesion and a preparation method thereof. BACKGROUND

[0002] Water-based polyurethane ink has the advantages of non-toxicity, environmental protection, good printing effect, excellent mechanical properties, and wide applicability, and is mainly composed of water-based polyurethane binder, pigment, and additive, and is mainly applied in printing, packaging, wood, plastic, metal substrate, etc. Traditional water-based polyurethane ink has poor adhesion and bonding performance with substrates such as aluminum foil, and poor heat resistance. The water-based polyurethane binder plays a key role in the performance of the ink, and the development of high-performance polyurethane materials is a research hotspot.

[0003] The water-based polyurethane binder is usually prepared from polyol, isocyanate monomer, and hydrophilic chain extender. Chinese patent CN115785387B discloses a polyurethane-polyurea water dispersion and its preparation method and application. The polyurethane water dispersion prepared from polyether polyol, polyester polyol, isocyanate, and triazole chain extender has good tensile strength, elongation, and resistance to polar solvents, but the patent does not improve the adhesion between polyurethane and substrates such as aluminum foil, nor does it improve the heat resistance of polyurethane, which is not conducive to the practical application of polyurethane in high-performance ink and other aspects. SUMMARY

[0004] The present application solves the problem of poor heat resistance of polyurethane ink, and improves the adhesion between polyurethane ink and metal substrate.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is: a water-based composite ink with high adhesion and a preparation method thereof, comprising 100 parts by weight of water-based triazole-based polyurethane binder, 20-30 parts by weight of pigment, 1.2-2 parts by weight of thickening agent, and 0.8-1.5 parts by weight of defoaming agent.

[0006] The preparation method is: adding water-based triazole-based polyurethane binder, pigment, thickening agent, and defoaming agent into a container, shearing and dispersing, and grinding to obtain a water-based composite ink with high adhesion.

[0007] The further preparation method of the water-based triazole-based polyurethane binder is: adding dry and dehydrated polyether polyol, isocyanate monomer, and dibutyltin dilaurate into a reaction kettle, and reacting in a nitrogen atmosphere, then adding acetone, small molecule chain extender, and water-based triazole chain extender, continuing to react, adding triethylamine for neutralization, and adding water for stirring and dispersing to obtain a water-based triazole-based polyurethane binder.

[0008] Further, the first reaction is stirred at 70-80 DEG C for 3-4 h; the second reaction is stirred at 40-50 DEG C for 1-1.5 h.

[0009] Further, the molar ratio of the polyether polyol, the isocyanate monomer, the small molecule chain extender, and the aqueous triazole chain extender is 1:(2.6-2.8):(0.9-1.1):(0.2-0.5).

[0010] Further, the polyether polyol is polyethylene glycol or polypropylene glycol.

[0011] Further, the isocyanate monomer is isophorone diisocyanate or toluene-2,4-diisocyanate.

[0012] Further, the small molecule chain extender is 1,4-butanediol.

[0013] Further, the preparation method of the aqueous triazole chain extender is: adding a solvent, 6-(N,N-dihydroxyethyl) amino-2,4-dichloro-1,3,5-triazine, 5-carboxyl-3-amino-1,2,4-triazole, and a sodium hydroxide aqueous solution into a reaction bottle provided with a condenser, stirring at 45-55 DEG C for 3-4 h first, then stirring at 85-95 DEG C for 6-7 h, removing the solvent by rotary evaporation, diluting with water, adjusting the pH to 3-4 by adding a hydrochloric acid solution dropwise, precipitating the product, purifying the product by recrystallization in water, and obtaining the aqueous triazole chain extender.

[0014]

[0015] Further, the solvent is acetone or 1,4-dioxane.

[0016] Further, the molar ratio of 6-(N,N-dihydroxyethyl) amino-2,4-dichloro-1,3,5-triazine, 5-carboxyl-3-amino-1,2,4-triazole, and sodium hydroxide is 1:(2-2.2):(4.8-6.2).

[0017] Beneficial technical effects: the 6-(N,N-dihydroxyethyl) amino-2,4-dichloro-1,3,5-triazine and 5-carboxyl-3-amino-1,2,4-triazole are reacted to obtain the aqueous triazole chain extender, which is then reacted with the polyether polyol, the isocyanate monomer, the small molecule chain extender, and the like to obtain the aqueous polyurethane connecting material; the aqueous triazole chain extender contains multiple hydrophilic groups such as carboxyl groups and triazole groups, which endow the polyurethane with excellent hydrophilicity and water solubility, good dispersibility in water, no layering, no precipitate, and the like, and are beneficial to improving the storage stability of the ink.

[0018] The application is a water-based triazole polyurethane connecting material, pigment, thickening agent and the like are compounded to obtain a water-based composite ink with high adhesion, the polyurethane molecular chain contains triazole groups and triazine structures with heat resistance, the triazole groups have strong coordination interaction with the surface of metal substrates such as aluminum single boards, thereby improving the adhesion performance and adhesion of the polyurethane paint film to the surface of the metal substrate, and the introduction of the triazine structure with heat resistance into the polyurethane molecular chain is beneficial to improve the thermal decomposition temperature and heat resistance of the ink paint film. DETAILED DESCRIPTION

[0019] The hydroxy acrylate resin and the preparation method thereof described in the application are further described below in combination with specific implementation cases. It should be understood that the embodiments given in the application are only used to illustrate the application and are not used to limit the scope of the application.

[0020] Example 1:

[0021] (1) 300 mL of acetone solvent, 60 mmol of 6-(N,N-dihydroxyethyl) amino-2,4-dichloro-1,3,5-triazine (CAS registration number 13436-79-8), 120 mmol of 5-carboxyl-3-amino-1,2,4-triazole (CAS registration number 3641-13-2), 40 mL of aqueous solution containing 288 mmol of sodium hydroxide, were added to a reaction bottle equipped with a condenser, first stirred at 45 DEG C for 4 h, then stirred at 95 DEG C for 6 h, the solvent was removed by rotary evaporation, diluted with 40 mL of water, the pH was adjusted to 4 by adding a 20% mass fraction hydrochloric acid solution dropwise, the precipitate was separated, and the product was purified by recrystallization in water to obtain an aqueous triazole chain extender. The structural formula is:

[0022] (2) 100 mmol of dry and dehydrated polyethylene glycol, 260 mmol of isofurokone diisocyanate, 1.2 mmol of dibutyltin dilaurate were added to a reaction kettle, stirred at 70 DEG C for 4 h under a nitrogen atmosphere, then 110 mL of acetone, 110 mmol of 1,4-butanediol, 20 mmol of aqueous triazole chain extender were added, stirred at 45 DEG C for 1.5 h, neutralized by adding 80 mmol of triethylamine, dispersed by stirring with 350 mL of water to obtain an aqueous triazole polyurethane connecting material.

[0023] (3) 1 kg of the aqueous triazole polyurethane connecting material, 200 g of the pigment titanium white paste BASF Dispers White 0022, 15 g of the thickening agent hydroxyethyl cellulose, and 12 g of the defoaming agent TEGO FOAMEX 1488 were added to a container, sheared and dispersed, and ground to obtain a water-based composite ink with high adhesion.

[0024] Example 2:

[0025] (1) Into a reaction flask equipped with a condenser, 250 mL of 1,4-dioxane solvent, 60 mmol of 6-(N,N-dihydroxyethyl)amino-2,4-dichloro-1,3,5-triazine, 132 mmol of 5-carboxy-3-amino-1,2,4-triazole, 50 mL of an aqueous solution containing 372 mmol of sodium hydroxide were added, and the reaction was stirred at 55°C for 3 h and then at 85°C for 7 h. The solvent was removed by rotary evaporation, and the mixture was diluted with 40 mL of water. The pH was adjusted to 3 by dropwise addition of a 20% by mass hydrochloric acid solution. Precipitates were separated by filtration, and the product was recrystallized from water to obtain an aqueous triazole chain extender.

[0026] (2) Into a reaction kettle, 100 mmol of dry and dehydrated polypropylene glycol 2000, 280 mmol of isophorone diisocyanate, and 1.3 mmol of dibutyltin dilaurate were added. The mixture was stirred at 80°C for 3 h under a nitrogen atmosphere. Then, 110 mL of acetone, 100 mmol of 1,4-butanediol, and 40 mmol of the aqueous triazole chain extender were added, and the mixture was stirred at 45°C for 1.5 h. The mixture was neutralized by adding 120 mmol of triethylamine and dispersed by adding 400 mL of water to obtain an aqueous triazolyl polyurethane binder.

[0027] (3) Into a container, 1 kg of the aqueous triazolyl polyurethane binder, 300 g of pigment titanium white paste BASF Dispers White 0022, 12 g of thickener hydroxyethyl cellulose, and 15 g of defoaming agent TEGO FOAMEX 1488 were added. The mixture was sheared and dispersed, and milled to obtain a high-adhesion aqueous composite ink.

[0028] Example 3:

[0029] (1) Into a reaction kettle, 100 mmol of dry and dehydrated polyethylene glycol 2000, 270 mmol of toluene-2,4-diisocyanate, and 1.2 mmol of dibutyltin dilaurate were added. The mixture was stirred at 75°C for 4 h under a nitrogen atmosphere. Then, 110 mL of acetone, 90 mmol of 1,4-butanediol, and 35 mmol of the aqueous triazole chain extender prepared in Example 1 were added, and the mixture was stirred at 50°C for 1 h. The mixture was neutralized by adding 110 mmol of triethylamine and dispersed by adding 400 mL of water to obtain an aqueous triazolyl polyurethane binder.

[0030] (2) Into a container, 1 kg of the aqueous triazolyl polyurethane binder, 260 g of pigment titanium white paste BASF Dispers White 0022, 14 g of thickener hydroxyethyl cellulose, and 15 g of defoaming agent TEGO FOAMEX 1488 were added. The mixture was sheared and dispersed, and milled to obtain a high-adhesion aqueous composite ink.

[0031] Example 4:

[0032] (1) 100 mmol of dry and dehydrated polyethylene glycol 2000, 280 mmol of toluene-2,4-diisocyanate, 1.2 mmol of dibutyltin dilaurate were added to a reaction kettle, stirred at 80 °C for 3 h under nitrogen atmosphere, then 100 mL of acetone, 90 mmol of 1,4-butanediol, 50 mmol of aqueous triazole chain extender (prepared from Example 1) were added, stirred at 40 °C for 1.5 h, 140 mmol of triethylamine was added for neutralization, 400 mL of water was added for stirring and dispersion, to obtain an aqueous triazole-based polyurethane binder.

[0033] (2) 1 kg of the aqueous triazole-based polyurethane binder, 200 g of the pigment titanium dioxide paste BASF Dispers White 0022, 20 g of the thickening agent hydroxyethyl cellulose, 10 g of the defoaming agent TEGO FOAMEX 1488 were added to a container, sheared and dispersed, and milled to obtain a high-adhesion aqueous composite ink.

[0034] Example 5:

[0035] (1) 100 mmol of dry and dehydrated polyethylene glycol 2000, 280 mmol of toluene-2,4-diisocyanate, 1.2 mmol of dibutyltin dilaurate were added to a reaction kettle, stirred at 80 °C for 3 h under nitrogen atmosphere, then 100 mL of acetone, 90 mmol of 1,4-butanediol, 50 mmol of aqueous triazole chain extender (prepared from Example 1) were added, stirred at 40 °C for 1.5 h, 140 mmol of triethylamine was added for neutralization, 400 mL of water was added for stirring and dispersion, to obtain an aqueous triazole-based polyurethane binder.

[0036] (2) 1 kg of the aqueous triazole-based polyurethane binder, 200 g of the pigment titanium dioxide paste BASF Dispers White 0022, 20 g of the thickening agent hydroxyethyl cellulose, 10 g of the defoaming agent TEGO FOAMEX 1488 were added to a container, sheared and dispersed, and milled to obtain a high-adhesion aqueous composite ink.

[0037] Comparative Example 1, the main difference between this comparative example and Example 1 is that 1,4-butanediol is used instead of the aqueous triazole chain extender.

[0038] (1) 100 mmol of dry and dehydrated polyethylene glycol, 260 mmol of isophorone diisocyanate, 1.2 mmol of dibutyltin dilaurate were added to a reaction kettle, stirred at 70 °C for 4 h under nitrogen atmosphere, then 110 mL of acetone, 130 mmol of 1,4-butanediol were added, stirred at 45 °C for 1.5 h, 350 mL of water was added for stirring and dispersion, to obtain a polyurethane binder.

[0039] (2) To the container, add 1 kg of aqueous triazole-based polyurethane binder, 200 g of pigment titanium dioxide paste BASF Dispers White 0022, 15 g of thickening agent hydroxyethyl cellulose, 12 g of defoaming agent TEGO FOAMEX 1488, shear dispersion, grinding, to obtain a composite ink.

[0040] Comparative Example 2, the main difference between this comparative example and Example 1 is that 2,2-dihydroxypropionic acid is used instead of aqueous triazole chain extender.

[0041] (1) Add 100 mmol of dry and dehydrated polyethylene glycol, 260 mmol of isofurone diisocyanate, 1.2 mmol of dibutyltin dilaurate to the reaction kettle, stir at 70°C for 4h under nitrogen atmosphere, then add 110 mL of acetone, 110 mmol of 1,4-butanediol, 20 mmol of 2,2-dihydroxypropionic acid, stir at 45°C for 1.5h, add 40 mmol of triethylamine for neutralization, add 350 mL of water for stirring and dispersion, to obtain an aqueous polyurethane binder.

[0042] (2) To the container, add 1 kg of aqueous polyurethane binder, 200 g of pigment titanium dioxide paste BASF Dispers White 0022, 15 g of thickening agent hydroxyethyl cellulose, 12 g of defoaming agent TEGO FOAMEX 1488, shear dispersion, grinding, to obtain an aqueous composite ink.

[0043] Comparative Example 3, the main difference between this comparative example and Example 1 is that triazole chain extender is used instead of aqueous triazole chain extender.

[0044] (1) Add 300 mL of acetone solvent, 60 mmol of 6-(N,N-dihydroxyethyl) amino-2,4-dichloro-1,3,5-triazine, 120 mmol of 3-amino-1,2,4-triazole (CAS No. 61-82-5, structural formula ) to the reaction bottle equipped with a condenser, 20 mL of aqueous solution containing 144 mmol of sodium hydroxide, first stir at 45°C for 4h, then stir at 95°C for 6h, rotary evaporation to remove the solvent, add water and ethyl acetate, extract and separate, rotary evaporation of the organic phase, the product is recrystallized in ethanol to obtain a triazole chain extender. The structural formula is

[0045] (2) Put 100 mmol of dry and dehydrated polyethylene glycol, 260 mmol of isofuroic diisocyanate, 1.2 mmol of dibutyl tin dilaurate into a reaction kettle, stir at 70°C for 4h under nitrogen atmosphere, then add 110 mL of acetone, 110 mmol of 1,4-butanediol, 20 mmol of triazole chain extender, stir at 45°C for 1.5h, add 350 mL of water and stir to disperse, to obtain a triazole-based polyurethane binder.

[0046] (3) Add 1 kg of triazole-based polyurethane binder, 200 g of pigment titanium white paste BASF DispersWhite 0022, 15 g of thickener hydroxyethyl cellulose, 12 g of defoaming agent TEGO FOAMEX 1488 into a container, shear disperse, grind, to obtain a composite ink.

[0047] The polyurethane binder is placed at room temperature for 4-12 months, and the dispersion is observed.

[0048] Table 1 Dispersion of binder

[0049]

[0050]

[0051] After testing, the polyurethane binder of examples 1-5 has good dispersion and high storage stability, mainly because the aqueous triazole chain extender contains multiple hydrophilic groups such as carboxyl and triazole, which endows the polyurethane with excellent hydrophilicity and water solubility, and the dispersion in water is very good, without stratification and sediment.

[0052] Comparative example 1 does not add a hydrophilic chain extender, and the polyurethane binder has obvious sediment after storage, with good dispersion and poor storage stability.

[0053] Comparative example 2 uses conventional 2,2-dihydroxypropionic acid as an aqueous chain extender, and the obtained polyurethane binder also has good hydrophilicity and water solubility, but there is a small amount of sediment in the solution after 12 months of storage.

[0054] The triazole chain extender of comparative example 3 does not contain hydrophilic carboxyl groups, and the dispersion and storage stability are not good.

[0055] The ink is sprayed on the surface of the aluminum veneer substrate, and baked and cured at 80°C for 8h. The film adhesion grade is tested according to the method of GB / T 9286-2021 standard.

[0056] The film is placed in a thermal gravimetric analyzer to test the thermal performance under nitrogen atmosphere, with a heating rate of 10°C / min and a temperature range of 25-700°C.

[0057] Table 2 Film performance test

[0058]

[0059]

[0060] The ink of Examples 1-5 and Comparative Example 3 has reached 0 level of adhesion grade on the surface of aluminum veneer substrate and has higher thermal decomposition temperature and good heat resistance compared with Comparative Example 1 after testing, mainly because the water-based triazole chain extender and the triazole chain extender containing triazole group and triazine structure with heat resistance are introduced into the polyurethane molecular chain, the triazole group has strong coordination interaction with the surface of metal substrate such as aluminum veneer, thereby improving the adhesion and adhesion of polyurethane paint film to the surface of metal substrate, and the polyurethane molecular chain introduces triazine structure with heat resistance, which is beneficial to improve the heat resistance of paint film and has higher thermal decomposition temperature.

[0061] Comparative Example 2 uses conventional 2,2-dimethylol propionic acid as chain extender, which does not contain triazole group and triazine group, and the coordination interaction between polyurethane and the surface of metal substrate such as aluminum veneer is low, resulting in poor adhesion and adhesion, and lower thermal decomposition temperature and poor heat resistance.

[0062] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments without departing from the principles and purposes of the present application within the scope of the present application.

Claims

1. A water-based composite ink with high adhesion, characterized in that, The water-based composite ink comprises 100 parts by weight of water-based triazole polyurethane binder, 20-30 parts by weight of pigment, 1.2-2 parts by weight of thickener, and 0.8-1.5 parts by weight of defoamer; The preparation method of the waterborne triazole-based polyurethane binder is as follows: dried and dehydrated polyether polyol, isocyanate monomer, and dibutyltin dilaurate are added to a reaction vessel and reacted under a nitrogen atmosphere. Then, acetone, a small molecule chain extender, and a compound with the following structural formula are added. The aqueous triazole chain extender was reacted further, and triethylamine was added for neutralization. Water was then added and stirred to disperse the mixture, resulting in an aqueous triazole-based polyurethane binder.

2. The high-adhesion water-based composite ink according to claim 1, characterized in that, The reaction is carried out in a nitrogen atmosphere by stirring at 70-80°C for 3-4 hours; the reaction is continued by stirring at 40-50°C for 1-1.5 hours.

3. The high-adhesion water-based composite ink according to claim 1, characterized in that, The molar ratio of the polyether polyol, isocyanate monomer, small molecule chain extender, and aqueous triazole chain extender is 1:(2.6-2.8):(0.9-1.1):(0.2-0.5).

4. The high-adhesion water-based composite ink according to claim 3, characterized in that, The polyether polyol is polyethylene glycol or polypropylene glycol; the isocyanate monomer is isoflurane diisocyanate or toluene-2,4-diisocyanate; and the small molecule chain extender is 1,4-butanediol.

5. The high-adhesion water-based composite ink according to claim 3, characterized in that, The preparation method of the aqueous triazole chain extender is as follows: A solvent, 6-(N,N-dihydroxyethyl)amino-2,4-dichloro-1,3,5-triazine, 5-carboxy-3-amino-1,2,4-triazole, and an aqueous sodium hydroxide solution are added to a reaction flask. After the reaction, the solvent is removed by rotary evaporation, diluted with water, and the pH is adjusted to 3-4 by adding hydrochloric acid solution. A precipitate is formed, filtered, and the product is recrystallized and purified in water to obtain the aqueous triazole chain extender.

6. The high-adhesion water-based composite ink according to claim 5, characterized in that, The solvent is acetone or 1,4-dioxane.

7. The high-adhesion water-based composite ink according to claim 5, characterized in that, The molar ratio of 6-(N,N-dihydroxyethyl)amino-2,4-dichloro-1,3,5-triazine, 5-carboxy-3-amino-1,2,4-triazole, and sodium hydroxide is 1:(2-2.2):(4.8-6.2).

8. The high-adhesion water-based composite ink according to claim 5, characterized in that, In the preparation method of the aqueous triazole chain extender, the reaction is first stirred at 45-55℃ for 3-4 hours, and then stirred at 85-95℃ for 6-7 hours.

9. A method for preparing a high-adhesion water-based composite ink as described in any one of claims 1-8, characterized in that, The preparation method is as follows: add water-based triazole polyurethane binder, pigment, thickener, and defoamer to a container, and then shear, disperse, and grind to obtain a water-based composite ink with high adhesion.

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