Degradable ink and method for preparing the same

Abstract

The application discloses degradable ink and a preparation method thereof, and belongs to the technical field of degradable ink. The raw materials are as follows in terms of weight percentage: 40-60 parts of water-based polyurethane resin, 4-8 parts of emulsifier, 22-34 parts of polylactic acid, 6-18 parts of modified chitosan, 9-15 parts of natural pigment, 3-5 parts of defoaming agent, 50-70 parts of deionized water and 5-10 parts of dispersing agent. The prepared ink takes the polyurethane resin as the main connecting material, and the ink is endowed with excellent heat resistance and corrosion resistance; the polylactic acid is used as the secondary connecting material, and the ink is endowed with certain heat resistance and degradability; the pigment is the natural pigment, and the ink is degradable; the ink is the water-based ink, and is more friendly to the environment; the modified chitosan can greatly enhance the antibacterial property, ultraviolet resistance and heat resistance of the ink, and the performance is stable; in conclusion, the application has important application value in the technical field of degradable ink.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of degradable ink, and particularly relates to a degradable ink and a preparation method thereof. BACKGROUND

[0002] With the rapid development of social economy and the enhancement of people's environmental awareness, the concept of green and sustainable development has gradually become the focus of global attention. In the printing industry, ink, as one of the important materials, its production and use have a significant impact on the environment. Traditional inks usually use petroleum-based resins as the main component, and add various organic solvents, pigments and additives. Although these inks have good printing performance, they release a large amount of volatile organic compounds (VOCs) during production and use, which not only pollutes the air, but also threatens human health. In addition, the ink in the waste printed matter is difficult to degrade naturally, and may cause secondary pollution during landfill or incineration treatment, further exacerbating environmental problems.

[0003] In recent years, the research and application of degradable materials have provided a new way to solve the above problems. Developing an ink that not only meets the printing needs but also has good biodegradability has become a hot direction in the industry. However, the existing "environmentally friendly" inks on the market often have some technical bottlenecks. For example, when the ink is used outdoors for a long time, such as outdoor advertising, it will be damaged by ultraviolet light, acid and alkali, and high temperature weather, etc. Generally, it cannot be used for more than a year, and serious yellowing and discoloration will occur. Its heat resistance and anti-aging performance are poor. Furthermore, when the ink is printed on packaging materials, the ink layer provides a habitat for the growth and reproduction of microorganisms. When people come into contact with food packaging, they are easy to be infected with bacteria or microorganisms, thereby affecting people's health. This limits its large-scale promotion and practical application.

[0004] From a technical point of view, the preparation of degradable ink needs to consider multiple factors. First of all, the selection of the base resin is crucial. The ideal resin should have excellent film-forming properties, appropriate flexibility and hardness, and be able to be decomposed by microorganisms into harmless small molecules under certain conditions. Currently commonly used degradable resins include polylactic acid (PLA), polycaprolactone (PCL) and starch-based polymers, etc., but they each have certain limitations, such as poor heat resistance. Secondly, the selection of pigments and fillers also needs to consider environmental friendliness and functionality. Traditional inorganic pigments have bright colors and good stability, but their production process has high energy consumption and is not easy to degrade. In view of the above, there is an urgent need to invent a heat-resistant and anti-aging degradable ink to meet the higher demands of the degradable ink technology field. SUMMARY

[0005] The present application aims to overcome the defects of the prior art and provides a degradable ink and a preparation method thereof.

[0006] The object of the present application can be achieved by the following technical solutions:

[0007] A preparation method of the degradable ink comprises the following steps:

[0008] The water-based polyurethane resin, the emulsifier, the polylactic acid, the modified chitosan, the natural pigment, the defoaming agent and the deionized water are uniformly mixed, and then are ground at room temperature.

[0009] Further, the raw materials are as follows according to weight parts: 40-60 parts of water-based polyurethane resin, 4-8 parts of emulsifier, 22-34 parts of polylactic acid, 6-18 parts of modified chitosan, 9-15 parts of natural pigment, 3-5 parts of defoaming agent, 50-70 parts of deionized water and 5-10 parts of dispersant.

[0010] Further, the emulsifier is one of sodium dodecyl sulfate and alkylphenol polyoxyethylene ether.

[0011] Further, the natural pigment is one of alizarin red, indigo, curcumin and monascus red.

[0012] Further, the defoaming agent is one of pentaerythritol stearate and polyoxypropylene glycerol ether.

[0013] Further, the dispersant is a polyacrylic acid sodium dispersant.

[0014] The ink takes the polyurethane resin as the main connecting material, which endows the ink with excellent heat resistance and corrosion resistance; takes the polylactic acid as the secondary connecting material, which not only endows the ink with certain heat resistance, but also endows the ink with degradability; secondly, the pigment added is a natural pigment, which is more easily degradable than an organic pigment; finally, the prepared ink is a water-based ink, which takes water as the solvent, has low VOC content and reduces the pollution to the environment, and is more friendly to the environment.

[0015] Further, the modified chitosan is prepared by the following steps:

[0016] Step 1, succinic acid, penta-methyl-piperidinol and N,N-dimethylformamide are added to a three-necked flask equipped with a thermometer and an electromagnetic stirring device, after stirring and mixing, dibutyl tin oxide and dicyclohexyl carbodiimide are added to the flask, the temperature is increased to 75℃, stirring is carried out for 5h, after the reaction is completed, filtration is carried out, the solvent is removed by distillation under reduced pressure, the intermediate product 1 is obtained by washing with anhydrous ethanol for multiple times and vacuum drying.

[0017] The dibutyltin oxide is used as a catalyst, and the dicyclohexyl carbodiimide is used as a dehydrating agent to perform esterification reaction. The molar ratio of succinic acid to piperidin-5-ylmethanol is controlled to be 1:1, and the succinic acid is slightly excessive. An intermediate product 1 is obtained. The specific reaction process is shown in the following:

[0018]

[0019] In step 2, the intermediate product 1, 4,4'-diaminodiphenyl sulfone and N,N-dimethylformamide are added into a three-necked flask provided with a thermometer and an electromagnetic stirring device. After stirring and mixing, the dicyclohexyl carbodiimide is added into the flask. The device is placed in a water bath at 50 °C, and heated for 3 hours. After the reaction is completed, part of the solvent is removed by rotary evaporation, and then column chromatography is performed for purification (the eluent is a mixed solvent of benzene / ethyl acetate, and the volume ratio of the two is 5:1). The eluent is removed by rotary evaporation, and the intermediate product 2 is obtained.

[0020] The dicyclohexyl carbodiimide is used as a dehydrating agent, and the amido of 4,4'-diaminodiphenyl sulfone reacts with the carboxyl of the intermediate product 1 to form an amide. The molar ratio of the two is controlled to be close to 1:1, and the 4,4'-diaminodiphenyl sulfone is slightly excessive. The intermediate product 2 is obtained. The specific reaction process is shown in the following:

[0021]

[0022] In step 3, the glutaraldehyde, the intermediate product 2, the piperidine and the N,N-dimethylformamide are added into a three-necked flask provided with a thermometer and an electromagnetic stirring device. After stirring and mixing, the temperature of the system is increased to 70 °C, and the temperature is maintained. The stirring reaction is performed for 6 hours. After the reaction is completed, the system is naturally cooled, and the solvent is removed by distillation under reduced pressure. Then, column chromatography is performed for purification (the eluent is a mixed solvent of benzene / ethyl acetate, and the volume ratio of the two is 3:2). The eluent is removed by rotary evaporation, and the intermediate product 3 is obtained.

[0023] The piperidine is used as a condensing agent, and the amido of the intermediate product 2 reacts with the aldehyde group of the glutaraldehyde to form an imine group (C=N Schiff base structure). The molar ratio of the two is controlled to be close to 1:1, and the glutaraldehyde is slightly excessive. The intermediate product 3 is obtained. The structure of the intermediate product 3 is shown in the following:

[0024]

[0025] Step 4, acetic acid and chitosan are added to a three-necked flask provided with a thermometer and a magnetic stirring device, stirring until the solid is completely dissolved, then intermediate product 3, piperidine and N,N-dimethylformamide are mixed and added to the flask, stirring at room temperature for 45 min, then sodium hydroxide solution is added dropwise to adjust the pH to 10, and the reaction is continued at 70 DEG C for 2 h, the reaction is completed, the precipitate is filtered, washed with acetone, ethanol, acetone and ethanol several times, and dried in an oven to obtain modified chitosan;

[0026] Under the action of piperidine, the aldehyde group on intermediate product 3 condenses with the amino group on chitosan to form an imine group (C=N Schiff base structure), and modified chitosan is obtained.

[0027] Further, in step 1, the amount ratio of succinic acid, pentamethylpiperidinol, N,N-dimethylformamide, dibutyltin oxide and dicyclohexyl carbodiimide is 12.7g:17.1g:100mL:0.2g:20.6g.

[0028] Further, in step 2, the amount ratio of intermediate product 1, 4,4'-diaminodiphenyl sulfone, N,N-dimethylformamide and dicyclohexyl carbodiimide is 27.1g:25.6g:120mL:20.6g.

[0029] Further, in step 3, the amount ratio of glutaraldehyde, intermediate product 2, piperidine and N,N-dimethylformamide is 11.2g:50.1g:15mL:100mL.

[0030] Further, in step 4, the amount ratio of acetic acid, chitosan, intermediate product 3, piperidine and N,N-dimethylformamide is 10mL:1g:13.7g:5mL:30mL.

[0031] Chitosan is a natural degradable material, which has good film-forming property, antibacterial property and stability; by modifying chitosan, the organic molecular chain is connected with chitosan through C=N, and the Schiff base structure can interact with bacterial proteins and enzymes, so that the synthesis of bacterial nucleotides and amino acids is blocked, and the antibacterial property of the matrix is greatly improved; in addition, the modified chitosan molecule also contains hindered amine and diphenyl sulfone structure, wherein the hindered amine can capture free radicals and inhibit photooxidation, and can improve the ultraviolet resistance of the matrix; the diphenyl sulfone structure contains benzene ring and sulfonic acid group, the benzene ring belongs to aryl, the π-π conjugated system in aromatic compounds has high thermal stability, which can effectively disperse heat, and the sulfonic acid group has high bond energy, which can further enhance the thermal stability of the matrix; finally, the organic molecular chain is connected with inorganic chitosan, which can improve the migration resistance of the organic small molecule, so that the performance of the modified chitosan is more long-lasting.

[0032] The beneficial effects of the present application are:

[0033] 1. The ink prepared by this invention uses polyurethane resin as the main binder, which endows the ink with excellent heat resistance and corrosion resistance.

[0034] 2. The use of polylactic acid as a secondary binder imparts certain heat resistance and biodegradability to the ink;

[0035] 3. The pigments are natural and biodegradable;

[0036] 4. The resulting ink is water-based, with low VOC content, making it more environmentally friendly;

[0037] 5. Modified chitosan was prepared through a series of reactions. Compared with ordinary chitosan, it has better hydrophobicity, is easier to exert its performance, and greatly enhances the antibacterial, UV resistance and a certain degree of heat resistance of the ink.

[0038] Therefore, the ink prepared by this invention has excellent heat resistance, UV resistance and antibacterial properties, and is environmentally friendly and biodegradable, thus having important application value in the field of biodegradable ink technology. Detailed Implementation

[0039] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0040] Example 1

[0041] Preparation of modified chitosan:

[0042] Step 1: Add 12.7g succinic acid, 17.1g pentamethylpiperidinol and 100mL N,N-dimethylformamide to a three-necked flask equipped with a thermometer and an electromagnetic stirrer. After stirring and mixing, add 0.2g dibutyltin oxide and 20.6g dicyclohexylcarbodiimide to the flask. Then raise the temperature to 75℃ and stir the reaction for 5h. After the reaction is complete, filter, remove the solvent by vacuum distillation, wash several times with anhydrous ethanol, and dry under vacuum to obtain intermediate product 1.

[0043] Step 2, 27.1 g of intermediate product 1, 25.6 g of 4, 4'-diaminodiphenyl sulfone and 120 mL of N, N-dimethylformamide were added into a three-neck flask equipped with a thermometer and a magnetic stirrer device, after stirring and mixing, 20.6 g of dicyclohexyl carbodiimide was added into the flask, the device was placed in a water bath at 50 °C, and the water bath was heated for 3 h. After the reaction was completed, part of the solvent was removed by rotary evaporation, and then column chromatography was used for purification (the eluent was a mixed solvent of benzene / ethyl acetate with a volume ratio of 5:1), and the eluent was removed by rotary evaporation to obtain intermediate product 2;

[0044] Step 3, 11.2 g of glutaraldehyde, 50.1 g of intermediate product 2, 15 mL of piperidine and 100 mL of N, N-dimethylformamide were added into a three-neck flask equipped with a thermometer and a magnetic stirrer device, after stirring and mixing, the temperature of the system was increased to 70 °C, and the temperature was maintained, and the reaction was stirred for 6 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and then column chromatography was used for purification (the eluent was a mixed solvent of benzene / ethyl acetate with a volume ratio of 3:2), and the eluent was removed by rotary evaporation to obtain intermediate product 3;

[0045] Step 4, 10 mL of acetic acid and 1 g of chitosan were added into a three-neck flask equipped with a thermometer and a magnetic stirrer device, and stirred until the solid was completely dissolved. Then 13.7 g of intermediate product 3, 5 mL of piperidine and 30 mL of N, N-dimethylformamide were mixed and added into the flask. The reaction was stirred at room temperature for 45 min, and then sodium hydroxide solution was added dropwise to adjust the pH to 10. The reaction was continued at 70 °C for 2 h. After the reaction was completed, the precipitate was obtained by filtration, and then washed with acetone, ethanol, acetone and ethanol for several times. The precipitate was dried in an oven to obtain the modified chitosan.

[0046] Example Two

[0047] Preparation of modified chitosan:

[0048] Step 1, 25.4 g of succinic acid, 34.2 g of pentamethylpiperidinol and 200 mL of N, N-dimethylformamide were added into a three-neck flask equipped with a thermometer and a magnetic stirrer device, after stirring and mixing, 0.4 g of dibutyltin oxide and 41.2 g of dicyclohexyl carbodiimide were added into the flask, and then the temperature was increased to 75 °C. The reaction was stirred for 5 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure, and then washed with anhydrous ethanol for several times. The product was dried under vacuum to obtain intermediate product 1;

[0049] Step 2, 54.2g of intermediate product 1, 51.2g of 4, 4'-diaminodiphenyl sulfone and 240mL of N, N-dimethylformamide were added into a three-neck flask equipped with a thermometer and a magnetic stirrer device, after stirring and mixing, 41.2g of dicyclohexyl carbodiimide was added into the flask, the device was placed in a water bath at 50℃, and heated for 3h, the reaction was completed, part of the solvent was removed by rotary evaporation, and then purified by column chromatography (the eluent was a mixed solvent of benzene / ethyl acetate with a volume ratio of 5:1), and the eluent was removed by rotary evaporation to obtain intermediate product 2;

[0050] Step 3, 22.4g of glutaraldehyde, 100.2g of intermediate product 2, 30mL of piperidine and 200mL of N, N-dimethylformamide were added into a three-neck flask equipped with a thermometer and a magnetic stirrer device, after stirring and mixing, the temperature of the system was increased to 70℃, and the temperature was maintained, and the reaction was stirred for 6h, after the reaction was completed, the system was naturally cooled, and the solvent was removed by distillation under reduced pressure, and then purified by column chromatography (the eluent was a mixed solvent of benzene / ethyl acetate with a volume ratio of 3:2), and the eluent was removed by rotary evaporation to obtain intermediate product 3;

[0051] Step 4, 20mL of acetic acid and 2g of chitosan were added into a three-neck flask equipped with a thermometer and a magnetic stirrer device, and stirred until the solid was completely dissolved, then 27.4g of intermediate product 3, 10mL of piperidine and 60mL of N, N-dimethylformamide were mixed and added into the flask, and stirred at room temperature for 45min, then sodium hydroxide solution was added dropwise to adjust the pH to 10, and the reaction was continued at 70℃ for 2h, the reaction was completed, and the precipitate was obtained by filtration, and then washed with acetone, ethanol, acetone and ethanol for several times, and dried in an oven to obtain the modified chitosan.

[0052] Example Three

[0053] 40g of water-based polyurethane resin, 4g of sodium dodecyl sulfate, 22g of polylactic acid, 6g of modified chitosan prepared in Example One, 9g of alizarin red, 3g of pentaerythritol stearate and 50g of deionized water were uniformly mixed, and then ground at room temperature, after grinding, 5g of polyacrylic acid sodium dispersant was added and stirred to obtain a degradable ink.

[0054] Example Four

[0055] 50g of water-based polyurethane resin, 6g of alkylphenol polyoxyethylene ether, 28g of polylactic acid, 12g of modified chitosan prepared in Example Two, 12g of indigo, 4g of polyoxypropylene glycerol ether and 60g of deionized water were uniformly mixed, and then ground at room temperature, after grinding, 7g of polyacrylic acid sodium dispersant was added and stirred to obtain a degradable ink.

[0056] Example Five

[0057] Mixing 60 g of aqueous polyurethane resin, 8 g of alkyl phenol polyoxyethylene ether, 34 g of polylactic acid, 18 g of modified chitosan prepared in Example 2, 15 g of curcumin, 5 g of polyoxypropylene glycerol ether and 70 g of deionized water uniformly, and grinding at room temperature, after grinding, adding 10 g of sodium polyacrylate dispersant, and stirring to obtain degradable ink.

[0058] Comparative Example 1

[0059] Using the same mass of ordinary chitosan to replace the modified chitosan in Example 5, and the remaining steps are the same as those in Example 5 to prepare degradable ink.

[0060] Comparative Example 2

[0061] Using commercially available antibacterial ink.

[0062] According to different test standards, the following performance tests are carried out on Examples 3, 4, 5, Comparative Examples 1 and 2:

[0063] The biodegradation rate is determined by using the national standard GB / T 21801-2008 "Chemicals: Respiratory Measurement Method for Rapid Biodegradation";

[0064] The antibacterial performance is determined by using the national standard GB / T 21866-2008 "Antibacterial Coatings (Paint Film) Antibacterial Property Determination Method and Antibacterial Effect";

[0065] The antibacterial performance retention rate (using the national standard GB / T 21866-2008) of Examples 3, 4, 5 and Comparative Example 2 after heat aging is determined by placing the sample in a 160℃ environment for 72h; the retention rate of antibacterial rate = antibacterial rate after test / antibacterial rate before test x 100%;

[0066] The sample is coated on a square plastic sheet with a side length of 5 cm, and after ultraviolet curing, the sample is aged by using the national standard GB / T 1865-2009 "Color Paint and Varnish Artificial Climate Aging and Artificial Radiation Exposure Filtered Xenon Arc Radiation"; and the sample change is observed;

[0067] The measured results are shown in the following table:

[0068]

[0069] As can be seen from the above table, the ink prepared by the examples of the present application has higher heat resistance, ultraviolet resistance and antibacterial property than the comparative examples, and has degradability, and has important application value in the field of degradable ink technology.

[0070] In the description, references to "one embodiment," "an example," "certain examples" etc. mean that the particular feature, structure, material, or characteristic being described is included in at least one embodiment or example of the application. The appearances of an item in various examples or embodiments is not necessarily indicative of a frequency of occurrence in the various examples or embodiments. Moreover, descriptions of well-known methods associated are omitted so as not to obscure the disclosure.

[0071] The foregoing merely illustrates the principles of the application. Various modifications and adaptations will occur to those skilled in the art after consideration of the preceding description. All such modifications and adaptations employing the principles of the application are intended to be within the scope of the claims.

Claims

1. A method for preparing a biodegradable ink, characterized in that, Includes the following steps: Waterborne polyurethane resin, emulsifier, polylactic acid, modified chitosan, natural pigment, defoamer and deionized water are mixed evenly and ground at room temperature. After grinding, dispersant is added and stirred again to obtain biodegradable ink. The modified chitosan is prepared through the following steps: Step 1: Add succinic acid, pentamethylpiperidinol and N,N-dimethylformamide to a flask, stir and mix, then add dibutyltin oxide and dicyclohexylcarbodiimide to the flask, raise the temperature to 75℃, stir and react for 5 hours. After the reaction is complete, filter, distill under reduced pressure, wash and dry to obtain intermediate product 1. Step 2: Add intermediate product 1, 4,4'-diaminodiphenyl sulfone and N,N-dimethylformamide to a flask, stir and mix, then add dicyclohexylcarbodiimide to the flask, place the apparatus in a water bath at 50°C and heat in the water bath for 3 hours. After the reaction is complete, evaporate by rotary evaporation, purify by column chromatography, and evaporate by rotary evaporation to obtain intermediate product 2. Step 3: Add glutaraldehyde, intermediate product 2, piperidine and N,N-dimethylformamide to a flask, stir and mix, raise the system temperature to 70℃, maintain the temperature and stir for 6 hours. After the reaction is complete, cool naturally, distill under reduced pressure, purify by column chromatography, and rotary evaporate to obtain intermediate product 3. Step 4: Add acetic acid and chitosan to the flask and stir until the solid is completely dissolved. Then, mix intermediate product 3, piperidine and N,N-dimethylformamide and add it to the flask. Stir the mixture at room temperature for 45 minutes. Then, add sodium hydroxide solution to adjust the pH to 10. Continue the reaction at 70°C for 2 hours. After the reaction is complete, filter, wash and dry to obtain modified chitosan. The raw materials are as follows by weight: 40-60 parts waterborne polyurethane resin, 4-8 parts emulsifier, 22-34 parts polylactic acid, 6-18 parts modified chitosan, 9-15 parts natural pigment, 3-5 parts defoamer, 50-70 parts deionized water and 5-10 parts dispersant. In step 1, the ratio of succinic acid, pentamethylpiperidinol, N,N-dimethylformamide, dibutyltin oxide, and dicyclohexylcarbodiimide is 12.7g:17.1g:100mL:0.2g:20.6g; in step 2, the ratio of intermediate product 1, 4,4'-diaminodiphenyl sulfone, N,N-dimethylformamide, and dicyclohexylcarbodiimide is 27.1g:25.6g:120mL:20.6g; in step 3, the ratio of glutaraldehyde, intermediate product 2, piperidine, and N,N-dimethylformamide is 11.2g:50.1g:15mL:100mL; and in step 4, the ratio of acetic acid, chitosan, intermediate product 3, piperidine, and N,N-dimethylformamide is 10mL:1g:13.7g:5mL:30mL.

2. The method for preparing a biodegradable ink according to claim 1, characterized in that, The natural pigment is one of madder red, indigo, curcumin, and red yeast rice.

3. The method for preparing a biodegradable ink according to claim 1, characterized in that, The defoamer is one of pentaerythritol stearate and polyoxypropylene glycerol ether.

4. A biodegradable ink, characterized in that, Prepared according to the method according to any one of claims 1-3.

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