A bio-based polyurethane water-based ink and its preparation process

Abstract

The present invention relates to the technical field of water-based inks, specifically a bio-based polyurethane water-based ink and a preparation process thereof. The process specifically comprises the following steps: S1: using ring-opened epoxidized soybean oil and modified epoxidized soybean oil as chain extenders to carry out a chain extension reaction with a polyurethane prepolymer to prepare a water-based polyurethane; S2: subjecting starch to a viscosity-reducing treatment, grafting it with 3-amino-5-carboxyl-N-methylbenzamide, and finally mixing and modifying it with ring-opened epoxidized soybean oil to prepare a modified starch; and S3: mixing the water-based polyurethane, modified starch, a water-based pigment, a thickener, a leveling agent, a defoamer, and deionized water in a proportioned manner, emulsifying, and defoaming to obtain a bio-based polyurethane water-based ink. The bio-based polyurethane water-based ink has excellent thermal stability, adhesion, and printing quality, is environmentally friendly, and exhibits significant practicality.

Description

Technical Field

[0001] The present invention relates to the technical field of water-based inks, in particular to a bio-based polyurethane water-based ink and a preparation process thereof. Background Art

[0002] Water-based inks are made using water as a solvent. They are prepared through a physical and chemical process combining specific water-based polymer resins, pigments, water, and cosolvents. Compared to organic solvent-based inks, water-based inks do not cause significant volatilization of organic solvents, are less toxic, and pose less of a health risk to production workers. With increasing emphasis on environmental protection and human health, water-based inks hold great promise for development. However, because they are less mature than solvent-based inks, they suffer from many performance deficiencies, such as inferior gloss, thermal stability, and smoothness.

[0003] Based on this, the present invention proposes a bio-based water-based polyurethane ink, which has important practical significance. Summary of the Invention

[0004] The purpose of the present invention is to provide a bio-based polyurethane water-based ink and a preparation process thereof, so as to solve the problems raised in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A bio-based polyurethane water-based ink comprises the following components: by weight, 30-50 parts of water-based polyurethane, 5-12 parts of modified starch, 2-10 parts of water-based pigment, 1-3 parts of thickener, 0.5-1 part of leveling agent, 1-2 parts of defoaming agent, and 20-30 parts of deionized water.

[0007] Furthermore, the preparation process of the bio-based polyurethane water-based ink comprises the following steps:

[0008] S1: Preparation of waterborne polyurethane:

[0009] S11: adding 20 parts of dehydrated diol, 10-20 parts of diisocyanate, 0.1-1 part of dibutyltin dilaurate, and 80 parts of acetone to a reactor, and stirring and heating to 70-85° C. under nitrogen protection to carry out prepolymerization for 1-6 hours to obtain a polyurethane prepolymer;

[0010] S12: Keeping the reaction temperature constant, 1-4 parts of ring-opened epoxy soybean oil and 1-4 parts of modified epoxy soybean oil are added to the polyurethane prepolymer to carry out chain extension reaction for 1-4 hours; then the temperature is lowered to 30-45°C, triethylamine is added to adjust the pH to 7-7.5, and then an appropriate amount of deionized water is added. The mixture is emulsified at high speed for 1-3 hours, and finally distilled under reduced pressure to obtain a waterborne polyurethane;

[0011] S2: Preparation of modified starch:

[0012] S21: Add hydrochloric acid solution to 20 parts of 40-50 wt% starch suspension to adjust the pH to 4-6, and stir for 1-2 hours; then add 12.8-20 parts of 3-amino-5-carboxyl-N-methylbenzamide and 0.13-0.6 parts of cyclohexanone peroxide, stir and heat to 100-120° C. for 1-4 hours, filter, wash, and dry to obtain product A;

[0013] S22: Add 10 parts of product A and 5-10 parts of ring-opened epoxidized soybean oil to the reactor, stir and mix for 10-60 minutes, and filter to obtain modified starch;

[0014] S3: Mix water-based polyurethane, modified starch, water-based pigment, thickener, leveling agent, defoamer and deionized water according to a proportion, subject to shear emulsification treatment for 2 to 10 minutes, and allow to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0015] Furthermore, the diol includes but is not limited to a combination of one or more of PEG-200, PEG-400, PEG-600, polycaprolactone diol, polycarbonate diol and polytetramethylene ether diol.

[0016] Furthermore, the diisocyanate includes, but is not limited to, a combination of one or more of toluene diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, and hexamethylene diisocyanate.

[0017] Furthermore, the mass fraction of isocyanate groups in the polyurethane prepolymer is 3.5-5%.

[0018] Furthermore, the mass ratio of the ring-opened epoxidized soybean oil to the modified epoxidized soybean oil is 1:1.

[0019] Furthermore, the solid content of the waterborne polyurethane is 40±2%.

[0020] Furthermore, the preparation method of the ring-opened epoxidized soybean oil is as follows: under nitrogen protection, 12 to 20 parts of epoxidized soybean oil, 3 to 16 parts of anhydrous methanol, 3 to 6 parts of a catalyst and 20 parts of tetrahydrofuran are added to a reactor, and after stirring and mixing evenly, the mixture is heated to 90 to 130° C., and a ring-opening reaction is carried out for 6 to 24 hours. After the reaction is terminated, the reaction system is naturally cooled to room temperature, and then filtered and distilled under reduced pressure to obtain the ring-opened epoxidized soybean oil.

[0021] Furthermore, the catalyst is a zeolite molecular sieve, including but not limited to any one of NH4ZSM-5, NaZSM-5, HZSM-5, LiZSM-5, KZSM-5, CsZSM-5, MgZSM-5, and CaZSM-5.

[0022] Furthermore, the modified epoxy soybean oil is obtained by modifying the ring-opened epoxy soybean oil, and its preparation method is as follows: (1) under nitrogen protection, 3-6 parts of ring-opened epoxy soybean oil, 0.8-1.2 parts of 2-butenoyl chloride and 0.008-0.012 parts of hydroquinone are added to a reactor, stirred and mixed evenly, and then heated to 50-140° C., refluxed for 6-48 hours, and the reaction is terminated. After the reaction system is naturally cooled to room temperature, unsaturated epoxy soybean oil is obtained; (2) 0.4-0.6 parts of methyl methacrylate, 0.2-0.4 parts of methyl acrylate, 0.4-0.6 parts of methacrylamide and 0.2-0.4 parts of acrylamide are added to the unsaturated epoxy soybean oil, stirred and mixed evenly, heated to 50-70° C., and then 0.012-0.045 parts of initiator are added to initiate polymerization for 1-6 hours to obtain modified epoxy soybean oil.

[0023] In the scheme, the amounts of ring-opened epoxidized soybean oil and 2-butenoyl chloride are controlled so that the hydroxyl groups on the ring-opened epoxidized soybean oil are not completely reacted with the acyl chloride groups on the 2-butenoyl chloride, and some hydroxyl groups are retained to react with the polyurethane prepolymer to achieve the purpose of chain extension modification.

[0024] Due to the poor thermal stability of polyurethane itself, the ink obtained by processing it is difficult to meet current practical needs. Generally, it is modified with related materials to improve its heat resistance and other properties. Epoxidized soybean oil is a cheap and readily available renewable biomaterial. It is often processed into polyols and used to modify and strengthen polyurethane materials. The mechanical properties and thermal stability of the processed polyurethane materials are correspondingly enhanced. Therefore, the present invention also designs to modify epoxy soybean oil to prepare the bio-based waterborne polyurethane material required for ink. In the present invention, the epoxy soybean oil and methanol are first subjected to a ring-opening reaction by the action of a catalyst to obtain a ring-opened epoxy soybean oil with a polyol structure; then, some of the hydroxyl groups on the epoxy soybean oil react with the acyl chloride groups on 2-butenoyl chloride to combine the two to obtain an unsaturated epoxy soybean oil containing unsaturated double bonds; finally, methyl methacrylate, methyl acrylate, methacrylamide and acrylamide are polymerized with the unsaturated bonds on the unsaturated epoxy soybean oil to prepare a modified epoxy soybean oil. The modified epoxy soybean oil retains some hydroxyl groups and also contains acrylate and acrylamide segments, which are compounded with the ring-opened epoxy soybean oil as a chain extender. The acrylate segments on the modified epoxy soybean oil can improve the wear resistance and glossiness of the polyurethane ink; the acrylamide segments mainly play a role in enhancing the thermal stability of the polyurethane ink; the ring-opened epoxy soybean oil has a high functionality and can obtain a polyurethane with a high degree of cross-linking, which has a positive effect on the thermal stability of the polyurethane ink. In addition, the ring-opened epoxy soybean oil contains a large number of hydroxyl groups, which can effectively form chemical bonds with the surface of the coated substrate, thereby improving the adhesion of the ink; and the acrylate segments can further improve the adhesion of the ink. The synergistic effect of the two can make the ink have excellent adhesion. Ultimately, the present invention prepares a water-based polyurethane that makes the ink have excellent wear resistance, thermal stability, glossiness and excellent adhesion.

[0025] Starch is a bio-based material rich in polar hydroxyl groups. Adding it to ink can enhance its adsorption capacity and improve the ink's heat resistance. In order to improve its dispersibility and make it better integrated with other components in the ink, the following treatments were carried out in the scheme: (1) The starch was first subjected to viscosity reduction treatment to enhance its dispersibility while reducing its negative impact on the fluidity of the ink; (2) 3-amino-5-carboxyl-N-methylbenzamide was grafted and copolymerized with starch to increase the number of starch branches and increase the complexity of the starch structure. The amide group contained in 3-amino-5-carboxyl-N-methylbenzamide has a certain effect on improving the thermal stability of starch. In addition, 3-amino-5-carboxyl-N-methylbenzamide itself can also undergo polymerization, further increasing the complexity of the starch structure, thereby improving the thermal stability and adhesion of the ink; (3) The treated starch was further mixed with ring-opened epoxidized soybean oil. The ring-opened epoxidized soybean oil weakened the hydrogen bonding of the starch itself and further promoted the dispersion of the starch in the ink. The modified starch introduced in the present invention can enhance the thermal stability and adhesion effect of the ink. At the same time, it also has a thickening effect, has a positive impact on the thixotropy of the ink, enhances the printing quality of the ink, and greatly improves the applicability of the water-based ink.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. In the present invention, ring-opened epoxy soybean oil and modified epoxy soybean oil are obtained by modifying epoxy soybean oil; the ring-opened epoxy soybean oil and modified epoxy soybean oil are then used as chain extenders to prepare a water-based polyurethane that has excellent wear resistance, thermal stability, gloss and adhesion.

[0028] 2. In the present invention, starch is modified to obtain modified starch; the modified starch has good dispersibility in ink and can well enhance the thermal stability and adhesion of the ink; at the same time, the modified starch has a positive effect on the thixotropy of the ink and can improve the printing quality of the ink;

[0029] 3. The present invention significantly improves the thermal stability and adhesion of ink through the synergistic effect of waterborne polyurethane and modified starch, and greatly improves the printing quality of ink, which has significant practicality.

[0030] 4. The epoxidized soybean oil and starch used in the present invention are both cheap and readily available bio-based materials, and the prepared bio-based polyurethane water-based ink is green and environmentally friendly. DETAILED DESCRIPTION

[0031] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0032] It should be noted that the purchasers of all raw materials involved in the present invention include, without any special restrictions, the following exemplary manufacturers:

[0033] Epoxidized soybean oil with a purity of 99% was purchased from Hubei Yongkuo Technology Co., Ltd.

[0034] NH4ZSM-5 molecular sieve was purchased from Runhe Catalyst Co., Ltd.

[0035] 2-Butenoyl chloride (98% purity), hydroquinone (99% purity), methyl methacrylate (99% purity), methyl acrylate (99% purity), methacrylamide (99% purity), acrylamide (99% purity), polytetramethylene ether glycol (99% purity), PEG-400 (99% purity), and isophorone diisocyanate (99% purity) were all purchased from Shanghai Jinjinle Industrial Co., Ltd.

[0036] 3-Amino-5-carboxyl-N-methylbenzamide with a purity of 98%, CAS number: 1954-96-7, was purchased from Shanghai Youhe Biotechnology Co., Ltd.

[0037] Cyclohexanone peroxide with a purity of 99% was purchased from Shanghai Future Industrial Co., Ltd.

[0038] The water-based pigment was Permanent Orange G, model YHO-1304, purchased from Yuhong Pigments Co., Ltd.

[0039] The model of thickener is H416E, purchased from Hefei Huayue New Material Technology Co., Ltd.

[0040] The model of the leveling agent is BYK-333 and the model of the defoaming agent is B-109, both of which were purchased from Guangdong Zhongke Hongtai New Materials Co., Ltd.

[0041] WL-305 water-based polyurethane ink, solid content 35%, was purchased from Xiamen Kangdilong Trading Co., Ltd.

[0042] Example 1: A bio-based polyurethane water-based ink and its preparation process:

[0043] S1: Preparation of waterborne polyurethane:

[0044] S11: 20 parts of dehydrated diol (10 parts of polytetramethylene glycol and 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate, and 80 parts of acetone were added to a reactor. Under nitrogen protection, the mixture was stirred and heated to 80° C. for prepolymerization for 4 hours to obtain a polyurethane prepolymer having an isocyanate group mass fraction of 4.2%.

[0045] S12: Under nitrogen protection, 16 parts of epoxidized soybean oil, 12.8 parts of anhydrous methanol, 4.8 parts of NH4ZSM-5 molecular sieves, and 20 parts of tetrahydrofuran were added to a reactor, and after stirring and mixing, the mixture was heated to 120°C for a ring-opening reaction for 12 hours. After the reaction was terminated, the reaction system was naturally cooled to room temperature, filtered, and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil;

[0046] S13: (1) Under nitrogen protection, 5 parts of ring-opened epoxy soybean oil, 1 part of 2-butenoyl chloride and 0.01 part of hydroquinone were added to the reactor, stirred and mixed evenly, and then heated to 85°C, refluxed for 24 hours, and the reaction was terminated. After the reaction system was naturally cooled to room temperature, unsaturated epoxy soybean oil was obtained; (2) 0.5 parts of methyl methacrylate, 0.3 parts of methyl acrylate, 0.5 parts of methacrylamide and 0.3 parts of acrylamide were added to the unsaturated epoxy soybean oil, stirred and mixed evenly, and heated to 60°C. 0.36 parts of ammonium persulfate were added to initiate polymerization for 4 hours to obtain modified epoxy soybean oil;

[0047] S14: While maintaining the reaction temperature, 2.5 parts of ring-opened epoxidized soybean oil and 2.5 parts of modified epoxidized soybean oil were added to the polyurethane prepolymer to carry out a chain extension reaction for 3 hours; the temperature was then lowered to 40° C., triethylamine was added to adjust the pH to 7, and then an appropriate amount of deionized water was added. The mixture was emulsified at high speed for 2 hours, and finally distilled under reduced pressure to obtain a waterborne polyurethane having a solid content of 40 wt %.

[0048] S2: Preparation of modified starch:

[0049] S21: Add hydrochloric acid solution to 20 parts of 45 wt% starch suspension to adjust the pH to 5.5, and stir for 1.5 hours; then add 17.5 parts of 3-amino-5-carboxyl-N-methylbenzamide and 0.35 parts of cyclohexanone peroxide, stir and heat to 110° C. for 3 hours, filter, wash, and dry to obtain product A;

[0050] S22: Add 10 parts of product A and 7.5 parts of ring-opened epoxidized soybean oil to the reactor, stir and mix for 45 minutes, and then filter to obtain modified starch;

[0051] S3: 43 parts of water-based polyurethane, 10 parts of modified starch, 6 parts of water-based pigment, 2 parts of thickener, 0.8 parts of leveling agent, 1.5 parts of defoaming agent and 25 parts of deionized water were mixed according to the proportion, and after shear emulsification treatment for 5 minutes, the mixture was allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0052] Example 2: A bio-based polyurethane water-based ink and its preparation process:

[0053] S1: Preparation of waterborne polyurethane:

[0054] S11: 20 parts of dehydrated diol (10 parts of polytetramethylene glycol and 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate, and 80 parts of acetone were added to a reactor. Under nitrogen protection, the mixture was stirred and heated to 80° C. for prepolymerization for 4 hours to obtain a polyurethane prepolymer having an isocyanate group mass fraction of 4.2%.

[0055] S12: Under nitrogen protection, 16 parts of epoxidized soybean oil, 12.8 parts of anhydrous methanol, 4.8 parts of NH4ZSM-5 molecular sieves, and 20 parts of tetrahydrofuran were added to a reactor, and after stirring and mixing, the mixture was heated to 120°C for a ring-opening reaction for 12 hours. After the reaction was terminated, the reaction system was naturally cooled to room temperature, filtered, and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil;

[0056] S13: (1) Under nitrogen protection, 5 parts of ring-opened epoxy soybean oil, 0.8 parts of 2-butenoyl chloride and 0.008 parts of hydroquinone were added to the reactor, stirred and mixed evenly, and then heated to 85°C, refluxed for 24 hours, and the reaction was terminated. After the reaction system was naturally cooled to room temperature, unsaturated epoxy soybean oil was obtained; (2) 0.4 parts of methyl methacrylate, 0.2 parts of methyl acrylate, 0.4 parts of methacrylamide and 0.2 parts of acrylamide were added to the unsaturated epoxy soybean oil, stirred and mixed evenly, and heated to 60°C. 0.27 parts of ammonium persulfate were added to initiate polymerization for 4 hours to obtain modified epoxy soybean oil;

[0057] S14: While maintaining the reaction temperature, 1 part of ring-opened epoxidized soybean oil and 1 part of modified epoxidized soybean oil were added to the polyurethane prepolymer to carry out a chain extension reaction for 3 hours; the temperature was then lowered to 40° C., triethylamine was added to adjust the pH to 7, and then an appropriate amount of deionized water was added. The mixture was emulsified at high speed for 2 hours, and finally distilled under reduced pressure to obtain a waterborne polyurethane having a solid content of 40 wt %.

[0058] S2: Preparation of modified starch:

[0059] S21: Add hydrochloric acid solution to 20 parts of 45 wt% starch suspension to adjust the pH to 5.5, and stir for 1.5 hours; then add 12.8 parts of 3-amino-5-carboxyl-N-methylbenzamide and 0.13 parts of cyclohexanone peroxide, stir and heat to 110° C. for 3 hours, filter, wash, and dry to obtain product A;

[0060] S22: Add 10 parts of product A and 5 parts of ring-opened epoxidized soybean oil to the reactor, stir and mix for 45 minutes, and then filter to obtain modified starch;

[0061] S3: 43 parts of water-based polyurethane, 10 parts of modified starch, 6 parts of water-based pigment, 2 parts of thickener, 0.8 parts of leveling agent, 1.5 parts of defoaming agent and 25 parts of deionized water were mixed according to the proportion, and after shear emulsification treatment for 5 minutes, the mixture was allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0062] Example 3: A bio-based polyurethane water-based ink and its preparation process:

[0063] S1: Preparation of waterborne polyurethane:

[0064] S11: 20 parts of dehydrated diol (10 parts of polytetramethylene glycol and 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate, and 80 parts of acetone were added to a reactor. Under nitrogen protection, the mixture was stirred and heated to 80° C. for prepolymerization for 4 hours to obtain a polyurethane prepolymer having an isocyanate group mass fraction of 4.2%.

[0065] S12: Under nitrogen protection, 20 parts of epoxidized soybean oil, 16 parts of anhydrous methanol, 6 parts of NH4ZSM-5 molecular sieves, and 20 parts of tetrahydrofuran were added to a reactor, and after stirring and mixing, the mixture was heated to 120°C for a ring-opening reaction for 12 hours. After the reaction was terminated, the reaction system was naturally cooled to room temperature, filtered, and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil;

[0066] S13: (1) Under nitrogen protection, 5 parts of ring-opened epoxy soybean oil, 1.2 parts of 2-butenoyl chloride and 0.012 parts of hydroquinone were added to the reactor, stirred and mixed evenly, and then heated to 85°C, refluxed for 24 hours, and the reaction was terminated. After the reaction system was naturally cooled to room temperature, unsaturated epoxy soybean oil was obtained; (2) 0.6 parts of methyl methacrylate, 0.4 parts of methyl acrylate, 0.6 parts of methacrylamide and 0.4 parts of acrylamide were added to the unsaturated epoxy soybean oil, stirred and mixed evenly, and heated to 60°C. 0.45 parts of ammonium persulfate were added to initiate polymerization for 4 hours to obtain modified epoxy soybean oil;

[0067] S14: While maintaining the reaction temperature, 4 parts of ring-opened epoxidized soybean oil and 4 parts of modified epoxidized soybean oil were added to the polyurethane prepolymer to carry out a chain extension reaction for 3 hours; the temperature was then lowered to 40° C., triethylamine was added to adjust the pH to 7, and then an appropriate amount of deionized water was added. The mixture was emulsified at high speed for 2 hours, and finally distilled under reduced pressure to obtain a waterborne polyurethane having a solid content of 40 wt %.

[0068] S2: Preparation of modified starch:

[0069] S21: Add hydrochloric acid solution to 20 parts of a 45 wt% starch suspension to adjust the pH to 5.5, and stir for 1.5 hours; then add 20 parts of 3-amino-5-carboxyl-N-methylbenzamide and 0.6 parts of cyclohexanone peroxide, stir and heat to 110° C. for 3 hours, filter, wash, and dry to obtain product A;

[0070] S22: Add 10 parts of product A and 10 parts of ring-opened epoxidized soybean oil to the reactor, stir and mix for 45 minutes, and then filter to obtain modified starch;

[0071] S3: 43 parts of water-based polyurethane, 10 parts of modified starch, 6 parts of water-based pigment, 2 parts of thickener, 0.8 parts of leveling agent, 1.5 parts of defoaming agent and 25 parts of deionized water were mixed according to the proportion, and after shear emulsification treatment for 5 minutes, the mixture was allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0072] Based on Example 1, control experiments are set up below, specifically comparative examples 1 to 5, as described below:

[0073] Comparative Example 1: Comparative Example 1 is based on Example 1, with the following adjustments: modified epoxy soybean oil is not added in the preparation of waterborne polyurethane, and other processes remain unchanged, specifically:

[0074] A bio-based polyurethane water-based ink and its preparation process:

[0075] S1: Preparation of waterborne polyurethane:

[0076] S11: 20 parts of dehydrated diol (10 parts of polytetramethylene glycol and 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate, and 80 parts of acetone were added to a reactor. Under nitrogen protection, the mixture was stirred and heated to 80° C. for prepolymerization for 4 hours to obtain a polyurethane prepolymer having an isocyanate group mass fraction of 4.2%.

[0077] S12: Under nitrogen protection, 16 parts of epoxidized soybean oil, 12.8 parts of anhydrous methanol, 4.8 parts of NH4ZSM-5 molecular sieves, and 20 parts of tetrahydrofuran were added to a reactor, and after stirring and mixing, the mixture was heated to 120°C for a ring-opening reaction for 12 hours. After the reaction was terminated, the reaction system was naturally cooled to room temperature, filtered, and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil;

[0078] S13: maintaining the reaction temperature constant, adding 5 parts of ring-opened epoxidized soybean oil to the polyurethane prepolymer and carrying out a chain extension reaction for 3 hours; then cooling to 40°C, adding triethylamine to adjust the pH to 7, then adding an appropriate amount of deionized water, emulsifying at high speed for 2 hours, and finally distilling under reduced pressure to obtain a waterborne polyurethane with a solid content of 40 wt%;

[0079] S2: Preparation of modified starch:

[0080] S21: Add hydrochloric acid solution to 20 parts of 45 wt% starch suspension to adjust the pH to 5.5, and stir for 1.5 hours; then add 17.5 parts of 3-amino-5-carboxyl-N-methylbenzamide and 0.35 parts of cyclohexanone peroxide, stir and heat to 110° C. for 3 hours, filter, wash, and dry to obtain product A;

[0081] S22: Add 10 parts of product A and 7.5 parts of ring-opened epoxidized soybean oil to the reactor, stir and mix for 45 minutes, and then filter to obtain modified starch;

[0082] S3: 43 parts of water-based polyurethane, 10 parts of modified starch, 6 parts of water-based pigment, 2 parts of thickener, 0.8 parts of leveling agent, 1.5 parts of defoaming agent and 25 parts of deionized water were mixed according to the proportion, and after shear emulsification treatment for 5 minutes, the mixture was allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0083] Comparative Example 2: Comparative Example 2 is based on Example 1, with the following adjustments: no modification of starch is performed, and other processes remain unchanged, specifically:

[0084] A bio-based polyurethane water-based ink and its preparation process:

[0085] S1: Preparation of waterborne polyurethane:

[0086] S11: 20 parts of dehydrated diol (10 parts of polytetramethylene glycol and 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate, and 80 parts of acetone were added to a reactor. Under nitrogen protection, the mixture was stirred and heated to 80° C. for prepolymerization for 4 hours to obtain a polyurethane prepolymer having an isocyanate group mass fraction of 4.2%.

[0087] S12: Under nitrogen protection, 16 parts of epoxidized soybean oil, 12.8 parts of anhydrous methanol, 4.8 parts of NH4ZSM-5 molecular sieves, and 20 parts of tetrahydrofuran were added to a reactor, and after stirring and mixing, the mixture was heated to 120°C for a ring-opening reaction for 12 hours. After the reaction was terminated, the reaction system was naturally cooled to room temperature, filtered, and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil;

[0088] S13: (1) Under nitrogen protection, 5 parts of ring-opened epoxy soybean oil, 1 part of 2-butenoyl chloride and 0.01 part of hydroquinone were added to the reactor, stirred and mixed evenly, and then heated to 85°C, refluxed for 24 hours, and the reaction was terminated. After the reaction system was naturally cooled to room temperature, unsaturated epoxy soybean oil was obtained; (2) 0.5 parts of methyl methacrylate, 0.3 parts of methyl acrylate, 0.5 parts of methacrylamide and 0.3 parts of acrylamide were added to the unsaturated epoxy soybean oil, stirred and mixed evenly, and heated to 60°C. 0.36 parts of ammonium persulfate were added to initiate polymerization for 4 hours to obtain modified epoxy soybean oil;

[0089] S14: While maintaining the reaction temperature, 2.5 parts of ring-opened epoxidized soybean oil and 2.5 parts of modified epoxidized soybean oil were added to the polyurethane prepolymer to carry out a chain extension reaction for 3 hours; the temperature was then lowered to 40° C., triethylamine was added to adjust the pH to 7, and then an appropriate amount of deionized water was added. The mixture was emulsified at high speed for 2 hours, and finally distilled under reduced pressure to obtain a waterborne polyurethane having a solid content of 40 wt %.

[0090] S2: 43 parts of water-based polyurethane, 10 parts of starch, 6 parts of water-based pigment, 2 parts of thickener, 0.8 parts of leveling agent, 1.5 parts of defoaming agent and 25 parts of deionized water were mixed according to the proportion, and after shear emulsification treatment for 5 minutes, the mixture was allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0091] Comparative Example 3: Comparative Example 3 is based on Example 1, with the following adjustments: 3-amino-5-carboxyl-N-methylbenzamide is not used to modify the starch, and other processes remain unchanged, specifically:

[0092] A bio-based polyurethane water-based ink and its preparation process:

[0093] S1: Preparation of waterborne polyurethane:

[0094] S11: 20 parts of dehydrated diol (10 parts of polytetramethylene glycol and 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate, and 80 parts of acetone were added to a reactor. Under nitrogen protection, the mixture was stirred and heated to 80° C. for prepolymerization for 4 hours to obtain a polyurethane prepolymer having an isocyanate group mass fraction of 4.2%.

[0095] S12: Under nitrogen protection, 16 parts of epoxidized soybean oil, 12.8 parts of anhydrous methanol, 4.8 parts of NH4ZSM-5 molecular sieves, and 20 parts of tetrahydrofuran were added to a reactor, and after stirring and mixing, the mixture was heated to 120°C for a ring-opening reaction for 12 hours. After the reaction was terminated, the reaction system was naturally cooled to room temperature, filtered, and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil;

[0096] S13: (1) Under nitrogen protection, 5 parts of ring-opened epoxy soybean oil, 1 part of 2-butenoyl chloride and 0.01 part of hydroquinone were added to the reactor, stirred and mixed evenly, and then heated to 85°C, refluxed for 24 hours, and the reaction was terminated. After the reaction system was naturally cooled to room temperature, unsaturated epoxy soybean oil was obtained; (2) 0.5 parts of methyl methacrylate, 0.3 parts of methyl acrylate, 0.5 parts of methacrylamide and 0.3 parts of acrylamide were added to the unsaturated epoxy soybean oil, stirred and mixed evenly, and heated to 60°C. 0.36 parts of ammonium persulfate were added to initiate polymerization for 4 hours to obtain modified epoxy soybean oil;

[0097] S14: While maintaining the reaction temperature, 2.5 parts of ring-opened epoxidized soybean oil and 2.5 parts of modified epoxidized soybean oil were added to the polyurethane prepolymer to carry out a chain extension reaction for 3 hours; the temperature was then lowered to 40° C., triethylamine was added to adjust the pH to 7, and then an appropriate amount of deionized water was added. The mixture was emulsified at high speed for 2 hours, and finally distilled under reduced pressure to obtain a waterborne polyurethane having a solid content of 40 wt %.

[0098] S2: Preparation of modified starch:

[0099] S21: Add hydrochloric acid solution to 20 parts of 45 wt% starch suspension to adjust the pH to 5.5, stir for 1.5 hours, filter, wash, and dry to obtain product A;

[0100] S22: Add 10 parts of product A and 7.5 parts of ring-opened epoxidized soybean oil to the reactor, stir and mix for 45 minutes, and then filter to obtain modified starch;

[0101] S3: 43 parts of water-based polyurethane, 10 parts of modified starch, 6 parts of water-based pigment, 2 parts of thickener, 0.8 parts of leveling agent, 1.5 parts of defoaming agent and 25 parts of deionized water were mixed according to the proportion, and after shear emulsification treatment for 5 minutes, the mixture was allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0102] Comparative Example 4: Comparative Example 4 is based on Example 1, with the following adjustments: the modified starch is not treated with ring-opening epoxidized soybean oil, and other processes remain unchanged, specifically:

[0103] A bio-based polyurethane water-based ink and its preparation process:

[0104] S1: Preparation of waterborne polyurethane:

[0105] S11: 20 parts of dehydrated diol (10 parts of polytetramethylene glycol and 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate, and 80 parts of acetone were added to a reactor. Under nitrogen protection, the mixture was stirred and heated to 80° C. for prepolymerization for 4 hours to obtain a polyurethane prepolymer having an isocyanate group mass fraction of 4.2%.

[0106] S12: Under nitrogen protection, 16 parts of epoxidized soybean oil, 12.8 parts of anhydrous methanol, 4.8 parts of NH4ZSM-5 molecular sieves, and 20 parts of tetrahydrofuran were added to a reactor, and after stirring and mixing, the mixture was heated to 120°C for a ring-opening reaction for 12 hours. After the reaction was terminated, the reaction system was naturally cooled to room temperature, filtered, and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil;

[0107] S13: (1) Under nitrogen protection, 5 parts of ring-opened epoxy soybean oil, 1 part of 2-butenoyl chloride and 0.01 part of hydroquinone were added to the reactor, stirred and mixed evenly, and then heated to 85°C, refluxed for 24 hours, and the reaction was terminated. After the reaction system was naturally cooled to room temperature, unsaturated epoxy soybean oil was obtained; (2) 0.5 parts of methyl methacrylate, 0.3 parts of methyl acrylate, 0.5 parts of methacrylamide and 0.3 parts of acrylamide were added to the unsaturated epoxy soybean oil, stirred and mixed evenly, and heated to 60°C. 0.36 parts of ammonium persulfate were added to initiate polymerization for 4 hours to obtain modified epoxy soybean oil;

[0108] S14: While maintaining the reaction temperature, 2.5 parts of ring-opened epoxidized soybean oil and 2.5 parts of modified epoxidized soybean oil were added to the polyurethane prepolymer to carry out a chain extension reaction for 3 hours; the temperature was then lowered to 40° C., triethylamine was added to adjust the pH to 7, and then an appropriate amount of deionized water was added. The mixture was emulsified at high speed for 2 hours, and finally distilled under reduced pressure to obtain a waterborne polyurethane having a solid content of 40 wt %.

[0109] S2: Preparation of modified starch:

[0110] S21: adding hydrochloric acid solution to 20 parts of a 45 wt% starch suspension to adjust the pH to 5.5, and stirring for 1.5 hours; then adding 17.5 parts of 3-amino-5-carboxyl-N-methylbenzamide and 0.35 parts of cyclohexanone peroxide, stirring and heating to 110° C. for 3 hours, filtering, washing, and drying to obtain modified starch;

[0111] S3: 43 parts of water-based polyurethane, 10 parts of modified starch, 6 parts of water-based pigment, 2 parts of thickener, 0.8 parts of leveling agent, 1.5 parts of defoaming agent and 25 parts of deionized water were mixed according to the proportion, and after shear emulsification treatment for 5 minutes, the mixture was allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0112] Comparative Example 5: Comparative Example 5 is based on Example 1, with the following adjustments: no modified starch is added, and other processes remain unchanged, specifically:

[0113] A bio-based polyurethane water-based ink and its preparation process:

[0114] S1: Preparation of waterborne polyurethane:

[0115] S11: 20 parts of dehydrated diol (10 parts of polytetramethylene glycol and 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate, and 80 parts of acetone were added to a reactor. Under nitrogen protection, the mixture was stirred and heated to 80° C. for prepolymerization for 4 hours to obtain a polyurethane prepolymer having an isocyanate group mass fraction of 4.2%.

[0116] S12: Under nitrogen protection, 16 parts of epoxidized soybean oil, 12.8 parts of anhydrous methanol, 4.8 parts of NH4ZSM-5 molecular sieves, and 20 parts of tetrahydrofuran were added to a reactor, and after stirring and mixing, the mixture was heated to 120°C for a ring-opening reaction for 12 hours. After the reaction was terminated, the reaction system was naturally cooled to room temperature, filtered, and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil;

[0117] S13: (1) Under nitrogen protection, 5 parts of ring-opened epoxy soybean oil, 1 part of 2-butenoyl chloride and 0.01 part of hydroquinone were added to the reactor, stirred and mixed evenly, and then heated to 85°C, refluxed for 24 hours, and the reaction was terminated. After the reaction system was naturally cooled to room temperature, unsaturated epoxy soybean oil was obtained; (2) 0.5 parts of methyl methacrylate, 0.3 parts of methyl acrylate, 0.5 parts of methacrylamide and 0.3 parts of acrylamide were added to the unsaturated epoxy soybean oil, stirred and mixed evenly, and heated to 60°C. 0.36 parts of ammonium persulfate were added to initiate polymerization for 4 hours to obtain modified epoxy soybean oil;

[0118] S14: While maintaining the reaction temperature, 2.5 parts of ring-opened epoxidized soybean oil and 2.5 parts of modified epoxidized soybean oil were added to the polyurethane prepolymer to carry out a chain extension reaction for 3 hours; the temperature was then lowered to 40° C., triethylamine was added to adjust the pH to 7, and then an appropriate amount of deionized water was added. The mixture was emulsified at high speed for 2 hours, and finally distilled under reduced pressure to obtain a waterborne polyurethane having a solid content of 40 wt %.

[0119] S2: Preparation of modified starch:

[0120] S21: Add hydrochloric acid solution to 20 parts of 45 wt% starch suspension to adjust the pH to 5.5, and stir for 1.5 hours; then add 17.5 parts of 3-amino-5-carboxyl-N-methylbenzamide and 0.35 parts of cyclohexanone peroxide, stir and heat to 110° C. for 3 hours, filter, wash, and dry to obtain product A;

[0121] S22: Add 10 parts of product A and 7.5 parts of ring-opened epoxidized soybean oil to the reactor, stir and mix for 45 minutes, and then filter to obtain modified starch;

[0122] S3: 43 parts of water-based polyurethane, 6 parts of water-based pigment, 2 parts of thickener, 0.8 parts of leveling agent, 1.5 parts of defoaming agent and 25 parts of deionized water were mixed according to the proportion, and after shear emulsification treatment for 5 minutes, the mixture was allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0123] Performance test: The bio-based polyurethane water-based ink prepared in Examples 1 to 3 and Comparative Examples 1 to 5 was coated on a PET film at a coating amount of 40 g / m 2 , and then conduct relevant performance tests and compare with the commercially available water-based polyurethane ink model WL-305, as follows:

[0124] (1) Thermal stability: After the ink on the surface of the PET film is dry, place it in 100℃ water and cook for 10 hours. After it cools down, observe whether the printed surface is wrinkled, ink is lost, or the printing is unclear;

[0125] (2) Adhesion performance test: According to the standard of GB / T 9286-2021, the adhesion of the ink is measured by the cross-cut method;

[0126] (3) Glossiness test: Ink glossiness test is performed according to the standard of GB / T 13217.2-2024;

[0127] The results of the above tests are shown in Table 1 below:

[0128] Table 1

[0129]

[0130] Results Analysis: The data in Table 1 above demonstrate that, through the treatment of epoxidized soybean oil and starch, the present invention produces a bio-based polyurethane water-based ink with excellent thermal stability, adhesion, and print quality. Comparisons between commercially available water-based polyurethane inks and the ink prepared in this invention demonstrate significant improvements in relevant properties, demonstrating significant practicality.

[0131] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A process for preparing a bio-based polyurethane water-based ink, characterized by: The following steps are involved: S1: Preparation of waterborne polyurethane: S11: adding 20 parts of dehydrated diol, 10-20 parts of diisocyanate, 0.1-1 part of dibutyltin dilaurate, and 80 parts of acetone to a reactor, and stirring and heating to 70-85° C. under nitrogen protection to carry out prepolymerization for 1-6 hours to obtain a polyurethane prepolymer; S12: Keeping the reaction temperature constant, 1-4 parts of ring-opened epoxy soybean oil and 1-4 parts of modified epoxy soybean oil are added to the polyurethane prepolymer to carry out chain extension reaction for 1-4 hours; then the temperature is lowered to 30-45°C, triethylamine is added to adjust the pH to 7-7.5, and then an appropriate amount of deionized water is added. The mixture is emulsified at high speed for 1-3 hours, and finally distilled under reduced pressure to obtain a waterborne polyurethane; S2: Preparation of modified starch: S21: Add hydrochloric acid solution to 20 parts of 40-50 wt% starch suspension to adjust the pH to 4-6, and stir for 1-2 hours; then add 12.8-20 parts of 3-amino-5-carboxyl-N-methylbenzamide and 0.13-0.6 parts of cyclohexanone peroxide, stir and heat to 100-120° C. for 1-4 hours, filter, wash, and dry to obtain product A; S22: Add 10 parts of product A and 5-10 parts of ring-opened epoxidized soybean oil to the reactor, stir and mix for 10-60 minutes, and filter to obtain modified starch; S3: Mix water-based polyurethane, modified starch, water-based pigment, thickener, leveling agent, defoamer and deionized water according to a certain ratio, subject to shear emulsification treatment for 2 to 10 minutes, and allow to stand for defoaming to obtain a bio-based polyurethane water-based ink; In S1, the preparation method of the ring-opened epoxidized soybean oil is as follows: under nitrogen protection, 12-20 parts of epoxidized soybean oil, 3-16 parts of anhydrous methanol, 3-6 parts of a catalyst, and 20 parts of tetrahydrofuran are added to a reactor, and after stirring and mixing, the mixture is heated to 90-130° C. to carry out a ring-opening reaction for 6-24 hours, and the reaction is terminated. After the reaction system is naturally cooled to room temperature, the reaction is filtered and distilled under reduced pressure to obtain the ring-opened epoxidized soybean oil; The modified epoxy soybean oil is obtained by modifying the ring-opened epoxy soybean oil, and the preparation method thereof is as follows: (1) under nitrogen protection, 3-6 parts of ring-opened epoxy soybean oil, 0.8-1.2 parts of 2-butenoyl chloride and 0.008-0.012 parts of hydroquinone are added to a reactor, stirred and mixed evenly, and then heated to 50-140° C., refluxed for 6-48 hours, and the reaction is terminated. After the reaction system is naturally cooled to room temperature, unsaturated epoxy soybean oil is obtained; (2) 0.4-0.6 parts of methyl methacrylate, 0.2-0.4 parts of methyl acrylate, 0.4-0.6 parts of methacrylamide and 0.2-0.4 parts of acrylamide are added to the unsaturated epoxy soybean oil, stirred and mixed evenly, and then heated to 50-70° C., and then 0.012-0.045 parts of initiator are added to initiate polymerization for 1-6 hours to obtain modified epoxy soybean oil.

2. The process for preparing a bio-based polyurethane water-based ink according to claim 1, characterized in that: The mass fraction of isocyanate groups in the polyurethane prepolymer is 3.5-5%.

3. The process for preparing a bio-based polyurethane water-based ink according to claim 1, wherein: The mass ratio of the ring-opened epoxidized soybean oil to the modified epoxidized soybean oil is 1:

1.

4. The process for preparing a bio-based polyurethane water-based ink according to claim 1, wherein: The solid content of the waterborne polyurethane is 40±2%.

5. The process for preparing a bio-based polyurethane water-based ink according to claim 1, wherein: The catalyst is a zeolite molecular sieve, including any one of NH4ZSM-5, NaZSM-5, HZSM-5, LiZSM-5, KZSM-5, CsZSM-5, MgZSM-5, and CaZSM-5.

6. The process for preparing a bio-based polyurethane water-based ink according to claim 1, characterized in that: The diol includes a combination of one or more of PEG-200, PEG-400, PEG-600, polycaprolactone diol, polycarbonate diol and polytetramethylene ether diol; the diisocyanate includes a combination of one or more of toluene diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate and hexamethylene diisocyanate.

7. The bio-based polyurethane water-based ink prepared by the process for preparing a bio-based polyurethane water-based ink according to any one of claims 1 to 6, characterized in that: The bio-based polyurethane water-based ink comprises the following components: by weight, 30-50 parts of water-based polyurethane, 5-12 parts of modified starch, 2-10 parts of water-based pigment, 1-3 parts of thickener, 0.5-1 part of leveling agent, 1-2 parts of defoaming agent, and 20-30 parts of deionized water.

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