A waterproof printing process for packaging boxes

Abstract

This invention relates to the field of ink printing technology, specifically a waterproof printing process for packaging paper boxes. To reduce environmental pollution, this invention prepares water-based inks for the printing process. First, this invention uses bis(4-aminophenoxy)dimethylsilane to react with 4-fluorophthalic anhydride, generating a fluorosilicone compound with free amino groups. Both fluorine and silicon elements have strong electronegativity, which can effectively reduce the surface energy of the printed paper box, thereby improving its waterproof performance. Then, this compound is reacted with 4,4'-dicarboxylic acid diphenyl ether and partially with the hydroxymethyl group in trimethylolethane to generate a diol compound containing fluorosilicone elements. This diol compound is then introduced into a polyurethane system to form a polyurethane emulsion. After mixing this emulsion with colorant and other components, it is used for printing on paper, ultimately improving the waterproof performance of the packaging paper box.

Description

Technical Field

[0001] This invention relates to the field of ink printing technology, specifically to a waterproof printing process for packaging paper boxes. Background Technology

[0002] Packaging cartons occupy an important position in the packaging industry. As an external packaging and decoration material for products, with the development of modern commerce, the role of packaging cartons is no longer limited to protecting the contents of the packaging. They also include the function of conveying some product information and promoting the packaged product. These have become important indicators that need to be considered in the production process of packaging cartons.

[0003] Currently, water-based inks are commonly used for printing packaging boxes. Although water-based inks are more environmentally friendly than traditional inks, they have poor waterproof performance after printing. Furthermore, due to the inherent properties of paper products, their waterproof performance faces significant challenges and is easily affected by the environment. Therefore, it is necessary to provide a waterproof printing process for packaging boxes to meet market demands. Summary of the Invention

[0004] The purpose of this invention is to provide a waterproof printing process for packaging paper boxes to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a waterproof printing process for packaging paper boxes, comprising the following steps:

[0006] S1. Preparation of aqueous polyurethane emulsion;

[0007] S11. Under a nitrogen atmosphere, bis(4-aminophenoxy)dimethylsilane was dispersed in DMF, mixed evenly, cooled to 5-8°C, 4-fluorophthalic anhydride was added, mixed evenly, p-toluenesulfonic acid was added, the temperature was raised to 85-92°C, and the reaction was carried out for 1-2 hours. Then the temperature was raised to 125-130°C, and the reaction was continued for 0.5-1 hour. Excess solvent was removed by rotary evaporation to obtain the terminal aminofluorosilane compound.

[0008] S12. Disperse the amino-terminated fluorosilicone compound in pure DMAc, cool to 5-8℃, mix thoroughly to obtain an amino-terminated fluorosilicone compound dispersion; disperse 4,4'-dicarboxylic acid diphenyl ether in pure DMAc, cool to 3-8℃, mix thoroughly, add the amino-terminated fluorosilicone compound dispersion dropwise, after the addition is complete, continue stirring for 3-5 min, add dibutyltin dilaurate, heat to 125-130℃ and react for 2-8 h, remove excess solvent by rotary evaporation to obtain a carboxyl-terminated fluorosilicone compound;

[0009] S13. Disperse the carboxyl-terminated fluorosilicone compound in DMF, mix thoroughly, add methanesulfonic acid, mix thoroughly, add trimethylolethane, heat to 85-92℃, react for 4-8 hours, and then remove excess solvent by rotary evaporation to obtain fluorosilicone modified diol.

[0010] S14. Mix isophorone diisocyanate with dibutyltin dilaurate, heat to 65-70℃, add fluorosilicone modified diol, heat to 92-98℃, maintain the temperature for 1.5-2 hours, then cool to 45-50℃, add 1,4-butanediol, continue heating to 92-98℃, react for 3-4 hours, add diethylenetriamine, heat to 82-85℃, continue reacting for 2-4 hours, add triethylamine to neutralize, continue reacting for 0.5-1 hours, add deionized water, and after high-speed emulsification and stirring, obtain an aqueous polyurethane emulsion;

[0011] S2. Coat both sides of the paper with the aqueous polyurethane emulsion prepared in step S1, with a coating amount of 20-30 g / m² on each side. 2 After coating, the paper is heated to 105-115℃ and dried for 5-15 minutes to obtain printing paper.

[0012] S3. Mix the water-based polyurethane emulsion, color paste, wetting and dispersing agent, defoamer, thickener, and deionized water. After high-speed mixing for 5-8 minutes, a waterproof printing coating is obtained.

[0013] S4. Inject the waterproof printing coating into the printing press and print on the printing paper. After printing, dry the paper at high temperature. After drying, you will get a packaging box.

[0014] Furthermore, in step S11, the mass ratio of bis(4-aminophenoxy)dimethylsilane, 4-fluorophthalic anhydride, and p-toluenesulfonic acid is 1:(0.55-0.62):(0.02-0.04).

[0015] Furthermore, in step S12, the mass ratio of the terminal amino fluorosilicone compound, 4,4'-dicarboxylic acid diphenyl ether, and dibutyltin dilaurate is (1.15-1.4):1:(0.02-0.04).

[0016] Furthermore, in step S13, the mass ratio of the terminal carboxyl fluorosilicone compound, methanesulfonic acid, and trimethylolpropane is (5.5-6.4):(0.05-0.1):1.

[0017] Furthermore, in step S14, the mass ratio of isophorone diisocyanate, dibutyltin dilaurate, fluorosilicone modified diol, 1,4-butanediol, diethylenetriamine, and triethylamine is 5:(0.03-0.05):(5.5-8).

[0018] Furthermore, in step S14, the mass ratio of fluorosilicone modified diol, 1,4-butanediol, diethylenetriamine, and triethylamine is (5.5-8):(0.5-0.8):(0.25-0.4):(0.15-0.3).

[0019] Furthermore, in step S14, the mass ratio of fluorosilicone modified diol to deionized water is (5.5-8):(14-24).

[0020] Furthermore, in step S3, the waterproof printing coating comprises the following components: 50-70 parts of waterborne polyurethane emulsion, 10-20 parts of color paste, 5-12 parts of wetting and dispersing agent, 1-2.5 parts of defoamer, 0.5-1.5 parts of thickener, and 30-45 parts of deionized water.

[0021] Furthermore, in step S3, the wetting and dispersing agent is BYK-193 type wetting and dispersing agent; the defoamer is an organosilicon defoamer; and the thickener is a cellulose ether thickener.

[0022] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0023] 1. In order to reduce environmental pollution and VOC emissions from inks, this invention prepares water-based inks for use in printing processes, thereby reducing the volatilization of organic solvents during printing and reducing pollution during the printing process. Simultaneously, this invention also adds a water-based polyurethane emulsion to the prepared waterproof printing coating. The strong adhesion between the polyurethane emulsion and paper after demulsification polymerization further enhances the adhesion of the ink printing. Furthermore, after demulsification, the polyurethane emulsion will cross-link again to form a coating layer, which covers the paper surface, thus preventing moisture penetration and improving the waterproof performance of the packaging box.

[0024] 2. To enhance the waterproof performance of printed packaging boxes, this invention first reacts silicon-containing bis(4-aminophenoxy)dimethylsilane with fluorine-containing 4-fluorophthalic anhydride. By controlling the reaction conditions, a fluorosilicone compound with free amino groups is generated under the catalysis of p-toluenesulfonic acid. Both fluorine and silicon have strong electronegativity, which can effectively reduce the surface energy of the printed paper box, thereby improving its waterproof performance. Both also have good flame-retardant properties, effectively enhancing the flame retardancy and safety of the paper box. Furthermore, this invention further reacts 4,4'-dicarboxylic acid diphenyl ether with the fluorosilicone compound to generate another fluorosilicone compound with free carboxyl groups, introducing a rigid benzene ring to further improve the abrasion resistance of the coating. Then, this invention further reacts it with trimethylolethane, controlling the reaction conditions to react some of the hydroxymethyl groups in the trimethylolethane, ultimately generating a diol compound with fluorosilicone elements. This diol compound is then introduced into a polyurethane system to form a polyurethane emulsion, ultimately improving the waterproof performance of the packaging paper box. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The bis(4-aminophenoxy)dimethylsilane and 4-fluorophthalic anhydride used in this application were provided by Shanghai Haohong Biomedical Technology Co., Ltd.; the 4,4'-dicarboxylic acid diphenyl ether and trimethylol ethane used were provided by Shanghai Aladdin Biochemical Technology Co., Ltd.; the silicone defoamer used was AT-618 defoamer provided by Datian Chemical; the thickener used was HEC30,000 viscosity hydroxyethyl cellulose thickener provided by Hubei Kewode Chemical Co., Ltd.; and the paper used was 1MM 3-layer A-grade corrugated cardboard provided by Shanghai Zhiying Environmental Protection Technology Co., Ltd.

[0027] Example 1. A waterproof printing process for packaging paper boxes, comprising the following steps:

[0028] S1. Preparation of aqueous polyurethane emulsion;

[0029] S11. Under a nitrogen atmosphere, 1 part by weight of bis(4-aminophenoxy)dimethylsilane was dispersed in DMF, mixed evenly, cooled to 5°C, 0.55 parts of 4-fluorophthalic anhydride were added, mixed evenly, 0.02 parts of p-toluenesulfonic acid were added, the temperature was raised to 85°C, and the reaction was carried out for 1 hour. Then the temperature was raised to 125°C and the reaction was continued for 0.5 hours. The excess solvent was removed by rotary evaporation to obtain the terminal aminofluorosilane compound.

[0030] S12. By weight, 1.15 parts of the amino-terminated fluorosilicone compound were dispersed in pure DMAc, cooled to 5°C, and mixed evenly to obtain an amino-terminated fluorosilicone compound dispersion; 1 part of 4,4'-dicarboxylic acid diphenyl ether was dispersed in pure DMAc, cooled to 3°C, and mixed evenly. The amino-terminated fluorosilicone compound dispersion was added dropwise over 2 hours. After the addition was completed, the mixture was stirred for 3 minutes, and then 0.02 parts of dibutyltin dilaurate were added. The mixture was heated to 125°C and reacted for 2 hours. Excess solvent was removed by rotary evaporation to obtain a carboxyl-terminated fluorosilicone compound.

[0031] S13. By weight, 5.5 parts of terminal carboxyl fluorosilicone compound were dispersed in DMF, mixed evenly, 0.05 parts of methanesulfonic acid were added, mixed evenly, 1 part of trimethylolethane was added, the temperature was raised to 85°C, and after reacting for 4 hours, the excess solvent was removed by rotary evaporation to obtain fluorosilicone modified diol.

[0032] S14. By weight, 5 parts of isophorone diisocyanate and 0.03 parts of dibutyltin dilaurate are mixed, heated to 65°C, 5.5 parts of fluorosilicone modified diol are added, the temperature is raised to 92°C, and the reaction is maintained at this temperature for 1.5 h. Then, the temperature is lowered to 45°C, 0.5 parts of 1,4-butanediol are added, the temperature is raised to 92°C, and the reaction is maintained for 3 h. Then, 0.25 parts of diethylenetriamine are added, the temperature is raised to 82°C, and the reaction is maintained for 2 h. Then, 0.15 parts of triethylamine are added for neutralization, and the reaction is maintained for 0.5 h. Then, 14 parts of deionized water are added, and the mixture is emulsified and stirred at a high speed of 15000 rpm for 0.5 h to obtain an aqueous polyurethane emulsion.

[0033] S2. Coat both sides of the paper with the aqueous polyurethane emulsion prepared in step S1, with a coating amount of 20 g / m² on each side. 2 After coating, the paper is heated to 105°C and dried for 5 minutes to obtain printing paper.

[0034] S3. Mix 50 parts of waterborne polyurethane emulsion, 10 parts of color paste, 5 parts of BYK-193 wetting and dispersing agent, 1 part of defoamer, 0.5 parts of thickener, and 30 parts of deionized water. Mix at a high speed of 12,000 rpm for 5 minutes to obtain a waterproof printing coating.

[0035] S4. Inject the waterproof printing coating into the printing press to print on the packaging paper. After printing, dry the paper at 115°C for 30 seconds. After drying, you will get the packaging box.

[0036] Example 2. A waterproof printing process for packaging cartons, comprising the following steps:

[0037] Compared with Example 1, this example increases the amount of waterborne polyurethane emulsion added in step S3;

[0038] S1. Preparation of aqueous polyurethane emulsion;

[0039] S11. Under a nitrogen atmosphere, 1 part by weight of bis(4-aminophenoxy)dimethylsilane was dispersed in DMF, mixed evenly, cooled to 5°C, 0.55 parts of 4-fluorophthalic anhydride were added, mixed evenly, 0.02 parts of p-toluenesulfonic acid were added, the temperature was raised to 85°C, and the reaction was carried out for 1 hour. Then the temperature was raised to 125°C and the reaction was continued for 0.5 hours. The excess solvent was removed by rotary evaporation to obtain the terminal aminofluorosilane compound.

[0040] S12. By weight, 1.15 parts of the amino-terminated fluorosilicone compound were dispersed in pure DMAc, cooled to 5°C, and mixed evenly to obtain an amino-terminated fluorosilicone compound dispersion; 1 part of 4,4'-dicarboxylic acid diphenyl ether was dispersed in pure DMAc, cooled to 3°C, and mixed evenly. The amino-terminated fluorosilicone compound dispersion was added dropwise over 2 hours. After the addition was completed, the mixture was stirred for 3 minutes, and then 0.02 parts of dibutyltin dilaurate were added. The mixture was heated to 125°C and reacted for 2 hours. Excess solvent was removed by rotary evaporation to obtain a carboxyl-terminated fluorosilicone compound.

[0041] S13. By weight, 5.5 parts of terminal carboxyl fluorosilicone compound were dispersed in DMF, mixed evenly, 0.05 parts of methanesulfonic acid were added, mixed evenly, 1 part of trimethylolethane was added, the temperature was raised to 85°C, and after reacting for 4 hours, the excess solvent was removed by rotary evaporation to obtain fluorosilicone modified diol.

[0042] S14. By weight, 5 parts of isophorone diisocyanate and 0.03 parts of dibutyltin dilaurate are mixed, heated to 65°C, 5.5 parts of fluorosilicone modified diol are added, the temperature is raised to 92°C, and the reaction is maintained at this temperature for 1.5 h. Then, the temperature is lowered to 45°C, 0.5 parts of 1,4-butanediol are added, the temperature is raised to 92°C, and the reaction is maintained for 3 h. Then, 0.25 parts of diethylenetriamine are added, the temperature is raised to 82°C, and the reaction is maintained for 2 h. Then, 0.15 parts of triethylamine are added for neutralization, and the reaction is maintained for 0.5 h. Then, 14 parts of deionized water are added, and the mixture is emulsified and stirred at a high speed of 15000 rpm for 0.5 h to obtain an aqueous polyurethane emulsion.

[0043] S2. Coat both sides of the paper with the aqueous polyurethane emulsion prepared in step S1, with a coating amount of 20 g / m² on each side. 2 After coating, the paper is heated to 105°C and dried for 5 minutes to obtain printing paper.

[0044] S3. Mix 70 parts of waterborne polyurethane emulsion, 10 parts of color paste, 5 parts of BYK-193 wetting and dispersing agent, 1 part of defoamer, 0.5 parts of thickener, and 30 parts of deionized water. Mix at a high speed of 12,000 rpm for 5 minutes to obtain a waterproof printing coating.

[0045] S4. Inject the waterproof printing coating into the printing press to print on the packaging paper. After printing, dry the paper at 115°C for 30 seconds. After drying, you will get the packaging box.

[0046] Example 3. A waterproof printing process for packaging cartons, comprising the following steps:

[0047] Compared with Example 2, this example increases the amount of 4-fluorophthalic anhydride added in step S11;

[0048] S1. Preparation of aqueous polyurethane emulsion;

[0049] S11. Under a nitrogen atmosphere, 1 part by weight of bis(4-aminophenoxy)dimethylsilane was dispersed in DMF, mixed evenly, cooled to 5°C, 0.62 parts of 4-fluorophthalic anhydride were added, mixed evenly, 0.02 parts of p-toluenesulfonic acid were added, the temperature was raised to 85°C, and the reaction was carried out for 1 h. Then the temperature was raised to 125°C and the reaction was continued for 0.5 h. The excess solvent was removed by rotary evaporation to obtain the terminal aminofluorosilane compound.

[0050] S12. By weight, 1.15 parts of the amino-terminated fluorosilicone compound were dispersed in pure DMAc, cooled to 5°C, and mixed evenly to obtain an amino-terminated fluorosilicone compound dispersion; 1 part of 4,4'-dicarboxylic acid diphenyl ether was dispersed in pure DMAc, cooled to 3°C, and mixed evenly. The amino-terminated fluorosilicone compound dispersion was added dropwise over 2 hours. After the addition was completed, the mixture was stirred for 3 minutes, and then 0.02 parts of dibutyltin dilaurate were added. The mixture was heated to 125°C and reacted for 2 hours. Excess solvent was removed by rotary evaporation to obtain a carboxyl-terminated fluorosilicone compound.

[0051] S13. By weight, 5.5 parts of terminal carboxyl fluorosilicone compound were dispersed in DMF, mixed evenly, 0.05 parts of methanesulfonic acid were added, mixed evenly, 1 part of trimethylolethane was added, the temperature was raised to 85°C, and after reacting for 4 hours, the excess solvent was removed by rotary evaporation to obtain fluorosilicone modified diol.

[0052] S14. By weight, 5 parts of isophorone diisocyanate and 0.03 parts of dibutyltin dilaurate are mixed, heated to 65°C, 5.5 parts of fluorosilicone modified diol are added, the temperature is raised to 92°C, and the reaction is maintained at this temperature for 1.5 h. Then, the temperature is lowered to 45°C, 0.5 parts of 1,4-butanediol are added, the temperature is raised to 92°C, and the reaction is maintained for 3 h. Then, 0.25 parts of diethylenetriamine are added, the temperature is raised to 82°C, and the reaction is maintained for 2 h. Then, 0.15 parts of triethylamine are added for neutralization, and the reaction is maintained for 0.5 h. Then, 14 parts of deionized water are added, and the mixture is emulsified and stirred at a high speed of 15000 rpm for 0.5 h to obtain an aqueous polyurethane emulsion.

[0053] S2. Coat both sides of the paper with the aqueous polyurethane emulsion prepared in step S1, with a coating amount of 20 g / m² on each side. 2 After coating, the paper is heated to 105°C and dried for 5 minutes to obtain printing paper.

[0054] S3. Mix 70 parts of waterborne polyurethane emulsion, 10 parts of color paste, 5 parts of BYK-193 wetting and dispersing agent, 1 part of defoamer, 0.5 parts of thickener, and 30 parts of deionized water. Mix at a high speed of 12,000 rpm for 5 minutes to obtain a waterproof printing coating.

[0055] S4. Inject the waterproof printing coating into the printing press to print on the packaging paper. After printing, dry the paper at 115°C for 30 seconds. After drying, you will get the packaging box.

[0056] Example 4. A waterproof printing process for packaging cartons, comprising the following steps:

[0057] Compared with Example 2, this example increases the amount of terminal carboxyl fluorosilicone compound added in step S13;

[0058] S1. Preparation of aqueous polyurethane emulsion;

[0059] S11. Under a nitrogen atmosphere, 1 part by weight of bis(4-aminophenoxy)dimethylsilane was dispersed in DMF, mixed evenly, cooled to 5°C, 0.55 parts of 4-fluorophthalic anhydride were added, mixed evenly, 0.02 parts of p-toluenesulfonic acid were added, the temperature was raised to 85°C, and the reaction was carried out for 1 hour. Then the temperature was raised to 125°C and the reaction was continued for 0.5 hours. The excess solvent was removed by rotary evaporation to obtain the terminal aminofluorosilane compound.

[0060] S12. By weight, 1.15 parts of the amino-terminated fluorosilicone compound were dispersed in pure DMAc, cooled to 5°C, and mixed evenly to obtain an amino-terminated fluorosilicone compound dispersion; 1 part of 4,4'-dicarboxylic acid diphenyl ether was dispersed in pure DMAc, cooled to 3°C, and mixed evenly. The amino-terminated fluorosilicone compound dispersion was added dropwise over 2 hours. After the addition was completed, the mixture was stirred for 3 minutes, and then 0.02 parts of dibutyltin dilaurate were added. The mixture was heated to 125°C and reacted for 2 hours. Excess solvent was removed by rotary evaporation to obtain a carboxyl-terminated fluorosilicone compound.

[0061] S13. By weight, 6.4 parts of terminal carboxyl fluorosilicone compound were dispersed in DMF, mixed evenly, 0.05 parts of methanesulfonic acid were added, mixed evenly, 1 part of trimethylolethane was added, the temperature was raised to 85°C, and after reacting for 4 hours, the excess solvent was removed by rotary evaporation to obtain fluorosilicone modified diol.

[0062] S14. By weight, 5 parts of isophorone diisocyanate and 0.03 parts of dibutyltin dilaurate are mixed, heated to 65°C, 5.5 parts of fluorosilicone modified diol are added, the temperature is raised to 92°C, and the reaction is maintained at this temperature for 1.5 h. Then, the temperature is lowered to 45°C, 0.5 parts of 1,4-butanediol are added, the temperature is raised to 92°C, and the reaction is maintained for 3 h. Then, 0.25 parts of diethylenetriamine are added, the temperature is raised to 82°C, and the reaction is maintained for 2 h. Then, 0.15 parts of triethylamine are added for neutralization, and the reaction is maintained for 0.5 h. Then, 14 parts of deionized water are added, and the mixture is emulsified and stirred at a high speed of 15000 rpm for 0.5 h to obtain an aqueous polyurethane emulsion.

[0063] S2. Coat both sides of the paper with the aqueous polyurethane emulsion prepared in step S1, with a coating amount of 20 g / m² on each side. 2 After coating, the paper is heated to 105°C and dried for 5 minutes to obtain printing paper.

[0064] S3. Mix 70 parts of waterborne polyurethane emulsion, 10 parts of color paste, 5 parts of BYK-193 wetting and dispersing agent, 1 part of defoamer, 0.5 parts of thickener, and 30 parts of deionized water. Mix at a high speed of 12,000 rpm for 5 minutes to obtain a waterproof printing coating.

[0065] S4. Inject the waterproof printing coating into the printing press to print on the packaging paper. After printing, dry the paper at 115°C for 30 seconds. After drying, you will get the packaging box.

[0066] Example 5. A waterproof printing process for packaging cartons, comprising the following steps:

[0067] S1. Preparation of aqueous polyurethane emulsion;

[0068] S11. Under a nitrogen atmosphere, 1 part by weight of bis(4-aminophenoxy)dimethylsilane was dispersed in DMF, mixed evenly, cooled to 5°C, 0.62 parts of 4-fluorophthalic anhydride were added, mixed evenly, 0.04 parts of p-toluenesulfonic acid were added, the temperature was raised to 85°C, and the reaction was carried out for 1 h. Then the temperature was raised to 125°C and the reaction was continued for 0.5 h. The excess solvent was removed by rotary evaporation to obtain the terminal aminofluorosilane compound.

[0069] S12. By weight, 1.4 parts of the amino-terminated fluorosilicone compound were dispersed in pure DMAc, cooled to 5°C, and mixed evenly to obtain an amino-terminated fluorosilicone compound dispersion; 1 part of 4,4'-dicarboxylic acid diphenyl ether was dispersed in pure DMAc, cooled to 3°C, and mixed evenly. The amino-terminated fluorosilicone compound dispersion was added dropwise over 2 hours. After the addition was completed, the mixture was stirred for 3 minutes, and then 0.04 parts of dibutyltin dilaurate were added. The mixture was heated to 125°C and reacted for 2 hours. Excess solvent was removed by rotary evaporation to obtain a carboxyl-terminated fluorosilicone compound.

[0070] S13. By weight, 6.4 parts of terminal carboxyl fluorosilicone compound were dispersed in DMF, mixed evenly, 0.1 parts of methanesulfonic acid were added, mixed evenly, 1 part of trimethylolethane was added, the temperature was raised to 85°C, and after reacting for 4 hours, the excess solvent was removed by rotary evaporation to obtain fluorosilicone modified diol.

[0071] S14. By weight, 5 parts of isophorone diisocyanate and 0.05 parts of dibutyltin dilaurate are mixed, heated to 65°C, 8 parts of fluorosilicone modified diol are added, the temperature is raised to 92°C, and the reaction is maintained at this temperature for 1.5 h. Then, the temperature is lowered to 45°C, 0.8 parts of 1,4-butanediol are added, the temperature is raised to 92°C, and the reaction is continued for 3 h. Then, 0.4 parts of diethylenetriamine are added, the temperature is raised to 82°C, and the reaction is continued for 2 h. Then, 0.3 parts of triethylamine are added for neutralization, and the reaction is continued for 0.5 h. Then, 21 parts of deionized water are added, and the mixture is emulsified and stirred at a high speed of 15000 rpm for 0.5 h to obtain an aqueous polyurethane emulsion.

[0072] S2. Coat both sides of the paper with the aqueous polyurethane emulsion prepared in step S1, with a coating amount of 20 g / m² on each side. 2 After coating, the paper is heated to 105°C and dried for 5 minutes to obtain printing paper.

[0073] S3. Mix 70 parts of waterborne polyurethane emulsion, 20 parts of color paste, 12 parts of BYK-193 wetting and dispersing agent, 2.5 parts of defoamer, 1.5 parts of thickener, and 45 parts of deionized water. Mix at a high speed of 12,000 rpm for 5 minutes to obtain a waterproof printing coating.

[0074] S4. Inject the waterproof printing coating into the printing press to print on the packaging paper. After printing, dry the paper at 115°C for 30 seconds. After drying, you will get the packaging box.

[0075] Comparative Example 1. A waterproof printing process for packaging cartons, comprising the following steps:

[0076] Compared to Example 2, this comparative example directly used 4-fluorophthalic anhydride to react with trihydroxymethane;

[0077] S1. Preparation of aqueous polyurethane emulsion;

[0078] S11. By weight, 1.2 parts of 4-fluorophthalic anhydride were dispersed in DMF and mixed evenly. Then, 0.05 parts of methanesulfonic acid were added and mixed evenly. Then, 1 part of tris(hydroxymethyl)ethane was added. The mixture was heated to 85°C and reacted for 4 hours. The excess solvent was removed by rotary evaporation to obtain fluorosilicone modified diol.

[0079] S12. By weight, 5 parts of isophorone diisocyanate and 0.03 parts of dibutyltin dilaurate are mixed, heated to 65°C, 5.5 parts of fluorosilicone modified diol are added, the temperature is raised to 92°C, and the reaction is maintained at this temperature for 1.5 h. Then, the temperature is lowered to 45°C, 0.5 parts of 1,4-butanediol are added, the temperature is raised to 92°C, and the reaction is continued for 3 h. Then, 0.25 parts of diethylenetriamine are added, the temperature is raised to 82°C, and the reaction is continued for 2 h. Then, 0.15 parts of triethylamine are added for neutralization, and the reaction is continued for 0.5 h. Then, 14 parts of deionized water are added, and the mixture is emulsified and stirred at a high speed of 15000 rpm for 0.5 h to obtain an aqueous polyurethane emulsion.

[0080] S2. Coat both sides of the paper with the aqueous polyurethane emulsion prepared in step S1, with a coating amount of 20 g / m² on each side. 2 After coating, the paper is heated to 105°C and dried for 5 minutes to obtain printing paper.

[0081] S3. Mix 70 parts of waterborne polyurethane emulsion, 10 parts of color paste, 5 parts of BYK-193 wetting and dispersing agent, 1 part of defoamer, 0.5 parts of thickener, and 30 parts of deionized water. Mix at a high speed of 12,000 rpm for 5 minutes to obtain a waterproof printing coating.

[0082] S4. Inject the waterproof printing coating into the printing press to print on the packaging paper. After printing, dry the paper at 115°C for 30 seconds. After drying, you will get the packaging box.

[0083] Comparative Example 2. A waterproof printing process for packaging cartons, comprising the following steps:

[0084] Compared to Example 2, this comparative example did not use fluorosilicone-modified diols;

[0085] S1. Preparation of aqueous polyurethane emulsion;

[0086] S11. By weight, 5 parts of isophorone diisocyanate and 0.03 parts of dibutyltin dilaurate are mixed, heated to 65°C, 1 part of 1,4-butanediol is added, the temperature is further increased to 92°C, and the reaction is carried out for 3 hours. Then, 0.25 parts of diethylenetriamine are added, the temperature is increased to 82°C, and the reaction is carried out for 2 hours. Then, 0.15 parts of triethylamine are added to neutralize the mixture, and the reaction is carried out for 0.5 hours. Then, 14 parts of deionized water are added, and the mixture is emulsified and stirred at a high speed of 15000 rpm for 0.5 hours to obtain an aqueous polyurethane emulsion.

[0087] S2. Coat both sides of the paper with the aqueous polyurethane emulsion prepared in step S1, with a coating amount of 20 g / m² on each side. 2 After coating, the paper is heated to 105°C and dried for 5 minutes to obtain printing paper.

[0088] S3. Mix 70 parts of waterborne polyurethane emulsion, 10 parts of color paste, 5 parts of BYK-193 wetting and dispersing agent, 1 part of defoamer, 0.5 parts of thickener, and 30 parts of deionized water. Mix at a high speed of 12,000 rpm for 5 minutes to obtain a waterproof printing coating.

[0089] S4. Inject the waterproof printing coating into the printing press to print on the packaging paper. After printing, dry the paper at 115°C for 30 seconds. After drying, you will get the packaging box.

[0090] Test: The printed samples prepared in Examples 1-5 and Comparative Examples 1-2 were cut into 50*100mm samples. Half of each sample was placed vertically in deionized water at 25°C and immersed for 24 hours. After immersion, the samples were removed and dried at 75°C to constant weight. The discoloration of the ink and water in the immersed part was then observed.

[0091] The printed samples prepared in Examples 1-5 and Comparative Examples 1-2 were cut into 50*100mm samples. They were completely immersed in deionized water at 25°C for 24 hours, then removed, the surface moisture was wiped off, weighed, and the water absorption rate was calculated.

[0092] The ink adhesion fastness of the printed samples prepared in Examples 1-5 and Comparative Examples 1-2 was tested according to GB / T 13217.7. The test method was the tape method, in which tape was attached to the surface of the printed matter, rolled back and forth three times with a roller press, and then peeled off at a speed of 0.8 m / s. The results were observed and calculated.

[0093] The test results are shown in the table below;

[0094]

[0095] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A waterproof printing process for packaging paper boxes, characterized in that, Includes the following steps: S1. Preparation of aqueous polyurethane emulsion; S11. Under a nitrogen atmosphere, bis(4-aminophenoxy)dimethylsilane was dispersed in DMF and mixed evenly. After cooling to 5-8°C, 4-fluorophthalic anhydride was added and mixed evenly. Then, p-toluenesulfonic acid was added, and the temperature was raised to 85-92°C. After reacting for 1-2 hours, the temperature was raised to 125-130°C and the reaction was continued for 0.5-1 hour. Excess solvent was removed by rotary evaporation to obtain the terminal aminofluorosilane compound. S12. Disperse the amino-terminated fluorosilicone compound in pure DMAC, cool to 5-8℃, mix thoroughly to obtain an amino-terminated fluorosilicone compound dispersion; disperse 4,4'-dicarboxylic acid diphenyl ether in pure DMAC, cool to 3-8℃, mix thoroughly, add the amino-terminated fluorosilicone compound dispersion dropwise, after the addition is complete, continue stirring for 3-5 min, add dibutyltin dilaurate, heat to 125-130℃ and react for 2-8 h, remove excess solvent by rotary evaporation to obtain a carboxyl-terminated fluorosilicone compound; S13. Disperse the carboxyl-terminated fluorosilicone compound in DMF, mix well, add methanesulfonic acid, mix well, add trimethylolethane, heat to 85-92℃, react for 4-8 hours, and then remove excess solvent by rotary evaporation to obtain fluorosilicone modified diol. S14. Mix isophorone diisocyanate with dibutyltin dilaurate, heat to 65-70℃, add fluorosilicone modified diol, heat to 92-98℃, maintain the temperature for 1.5-2 hours, then cool to 45-50℃, add 1,4-butanediol, continue to heat to 92-98℃, react for 3-4 hours, add diethylenetriamine, heat to 82-85℃, continue to react for 2-4 hours, add triethylamine to neutralize, continue to react for 0.5-1 hours, add deionized water, and after high-speed emulsification and stirring, obtain an aqueous polyurethane emulsion; S2. Coat both sides of the paper with the aqueous polyurethane emulsion prepared in step S1, with a coating amount of 20-30 g / m² on each side. 2 After coating, the paper is heated to 105-115℃ and dried for 5-15 minutes to obtain printing paper. S3. Mix the water-based polyurethane emulsion, color paste, wetting and dispersing agent, defoamer, thickener, and deionized water. After high-speed mixing for 5-8 minutes, a waterproof printing coating is obtained. S4. Inject the waterproof printing coating into the printing press and print on the printing paper. After printing, dry the paper at high temperature. After drying, you will get a packaging box.

2. The waterproof printing process for packaging paper boxes according to claim 1, characterized in that: In step S11, the mass ratio of bis(4-aminophenoxy)dimethylsilane, 4-fluorophthalic anhydride, and p-toluenesulfonic acid is 1:(0.55-0.62):(0.02-0.04).

3. The waterproof printing process for packaging paper boxes according to claim 1, characterized in that: In step S12, the mass ratio of the terminal amino fluorosilicone compound, 4,4'-dicarboxylic acid diphenyl ether, and dibutyltin dilaurate is (1.15-1.4):1:(0.02-0.04).

4. The waterproof printing process for packaging paper boxes according to claim 1, characterized in that: In step S13, the mass ratio of the terminal carboxyl fluorosilicone compound, methanesulfonic acid, and trimethylolpropane is (5.5-6.4):(0.05-0.1):

1.

5. A waterproof printing process for packaging paper boxes according to claim 1, characterized in that: In step S14, the mass ratio of isophorone diisocyanate, dibutyltin dilaurate, and fluorosilicone modified diol is 5:(0.03-0.05):(5.5-8).

6. The waterproof printing process for packaging paper boxes according to claim 1, characterized in that: In step S14, the mass ratio of fluorosilicone modified diol, 1,4-butanediol, diethylenetriamine, and triethylamine is (5.5-8):(0.5-0.8):(0.25-0.4):(0.15-0.3).

7. The waterproof printing process for packaging paper boxes according to claim 1, characterized in that: In step S14, the mass ratio of fluorosilicone modified diol to deionized water is (5.5-8):(14-21).

8. A waterproof printing process for packaging paper boxes according to claim 1, characterized in that: In step S3, the waterproof printing coating includes the following components: 50-70 parts of water-based polyurethane emulsion, 10-20 parts of color paste, 5-12 parts of wetting and dispersing agent, 1-2.5 parts of defoamer, 0.5-1.5 parts of thickener, and 30-45 parts of deionized water.

9. A waterproof printing process for packaging paper boxes according to claim 1, characterized in that: In step S3, the wetting and dispersing agent is BYK-193 type wetting and dispersing agent; the defoamer is an organosilicon defoamer; and the thickener is a cellulose ether thickener.

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