Bio-based polyurethane water-based ink and preparation process thereof

Abstract

The invention relates to the technical field of water-based ink, in particular to bio-based polyurethane water-based ink and a preparation process thereof. The preparation method specifically comprises the following steps: S1, adopting ring-opening epoxidized soybean oil and modified epoxidized soybean oil as chain extenders, and carrying out chain extension reaction on the chain extenders and a polyurethane prepolymer to prepare waterborne polyurethane; s2, performing viscosity reduction treatment on starch, then grafting with 3-amino-5 carboxyl-N-methyl benzamide, and finally mixing with ring-opening epoxidized soybean oil for modification to prepare modified starch; s3, mixing the waterborne polyurethane, the modified starch, the waterborne pigment, the thickening agent, the flatting agent, the defoaming agent and the deionized water according to the proportion, emulsifying and defoaming to obtain the bio-based polyurethane waterborne ink. The bio-based polyurethane water-based ink has excellent thermal stability, adhesive capacity and printing quality, is green and environment-friendly, and shows remarkable practicability.

Description

Technical Field

[0001] The 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 ink is an ink made with water as solvent. It is made of specific water-based polymer resin, pigment, water and co-solvent through physical and chemical processes. Compared with organic solvent-based ink, water-based ink will not cause a large amount of organic solvent volatilization, has low toxicity, and has little impact on the health of production workers. Today, when more and more attention is paid to environmental protection and personal health, water-based ink has great development prospects. However, since the development of water-based ink is not as mature as that of solvent-based ink, it has deficiencies in many properties. Compared with solvent-based ink, its glossiness, thermal stability and smoothness are poor.

[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 to solve the problems raised in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions: 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 parts of leveling agent, 1-2 parts of defoaming agent and 20-30 parts of deionized water.

[0006] Furthermore, the preparation process of the bio-based polyurethane water-based ink comprises the following steps: S1: Preparation of waterborne polyurethane: S11: adding 20 parts of dehydrated diol, 10-20 parts of diisocyanate, 0.1-1 parts of dibutyltin dilaurate and 80 parts of acetone into a reaction kettle, stirring and heating to 70-85° C. under nitrogen protection, and performing prepolymerization for 1-6 hours to obtain a polyurethane prepolymer; S12: Keeping the reaction temperature unchanged, 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, high-speed emulsification is performed for 1-3 hours, and finally reduced pressure distillation is performed to obtain waterborne polyurethane; S2: Preparation of modified starch: S21: Add hydrochloric acid solution to 20 parts of 40-50wt% 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: adding 10 parts of product A and 5-10 parts of ring-opened epoxidized soybean oil into a reactor, stirring and mixing for 10-60 minutes, filtering, and modifying starch; 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.

[0007] 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 glycol.

[0008] 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.

[0009] Furthermore, the mass fraction of isocyanate groups in the polyurethane prepolymer is 3.5-5%.

[0010] Furthermore, the mass ratio of the ring-opened epoxidized soybean oil to the modified epoxidized soybean oil is 1:1.

[0011] Furthermore, the solid content of the waterborne polyurethane is 40±2%.

[0012] 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, 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, the reaction is terminated, and after the reaction system is naturally cooled to room temperature, the ring-opened epoxidized soybean oil is obtained by filtering and distilling under reduced pressure.

[0013] Furthermore, the catalyst is a zeolite molecular sieve, including but not limited to NH 4 Any one of ZSM-5, NaZSM-5, HZSM-5, LiZSM-5, KZSM-5, CsZSM-5, MgZSM-5, and CaZSM-5.

[0014] 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.

[0015] In the scheme, the dosage of ring-opened epoxidized soybean oil and 2-butenoyl chloride is 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 part of the hydroxyl groups are retained to react with the polyurethane prepolymer to achieve the purpose of chain extension modification.

[0016] Since the thermal stability of polyurethane itself is poor, the ink processed by it is difficult to meet the current actual needs. Generally, relevant materials are used to modify it in combination to improve its heat resistance and other properties. Epoxidized soybean oil is a cheap and easily available renewable biomaterial. It is often processed into polyols for modifying and strengthening polyurethane materials. The mechanical properties and thermal stability of the processed polyurethane materials are correspondingly enhanced. Therefore, the present invention also designs to modify the epoxy soybean oil to prepare the bio-based waterborne polyurethane material required for the ink. In the present invention, the epoxy soybean oil and methanol are firstly reacted with a catalyst to obtain an open-ring epoxy soybean oil with a polyol structure; then, part of the hydroxyl groups on it react with the acyl chloride group on 2-butenoyl chloride to combine the two to obtain an unsaturated epoxy soybean oil containing an unsaturated double bond; 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 functionality of the ring-opened epoxy soybean oil is relatively large, and a polyurethane with a large degree of cross-linking can be obtained, 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 effect of the ink; and the acrylate segments can also further improve the adhesion effect of the ink, and the synergistic effect of the two can make the ink have excellent adhesion. Finally, the present invention prepares a water-based polyurethane that makes the ink have excellent wear resistance, thermal stability, glossiness and excellent adhesion.

[0017] Starch is a bio-based material rich in polar hydroxyl groups. Adding it to ink can enhance its adsorption 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 performed 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 to 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 to weaken the hydrogen bonding of the starch itself through the ring-opened epoxidized soybean oil, further promoting 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, and at the same time has a thickening effect, which has a positive effect on the thixotropy of the ink, thereby enhancing the printing quality of the ink and greatly improving the applicability of the water-based ink.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. In the present invention, ring-opened epoxy soybean oil and modified epoxy soybean oil are obtained by modifying epoxy soybean oil; and the ring-opened epoxy soybean oil and modified epoxy soybean oil are used as chain extenders to prepare water-based polyurethane that enables the ink to have excellent wear resistance, thermal stability, gloss and excellent adhesion. 2. In the present invention, the starch is modified to obtain modified starch; the modified starch has good dispersibility in the 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; 3. In the present invention, through the synergistic effect of waterborne polyurethane and modified starch, the thermal stability and adhesion of the ink are significantly improved, and the printing quality of the ink is also greatly improved, which has significant practicality; 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

[0019] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] It should be noted that the purchasers of all raw materials involved in the present invention include, without any special restrictions, illustratively: Epoxidized soybean oil with a purity of 99% was purchased from Hubei Yongkuo Technology Co., Ltd.; NH 4 ZSM-5 molecular sieve, purchased from Runhe Catalyst Co., Ltd.; 2-Butenoyl chloride with a purity of 98%, hydroquinone with a purity of 99%, methyl methacrylate with a purity of 99%, methyl acrylate with a purity of 99%, methacrylamide with a purity of 99%, acrylamide with a purity of 99%, polytetramethylene glycol with a purity of 99%, PEG-400 with a purity of 99%, and isophorone diisocyanate with a purity of 99% were all purchased from Shanghai Jinjinle Industrial Co., Ltd.; 3-Amino-5-carboxyl-N-methylbenzamide, purity 98%, CAS number: 1954-96-7, purchased from Shanghai Youhe Biotechnology Co., Ltd.; Cyclohexanone peroxide with a purity of 99% was purchased from Shanghai Future Industrial Co., Ltd. The water-based pigment is Permanent Orange G, model YHO-1304, purchased from Yuhong Pigment Co., Ltd. The model of thickener is H416E, purchased from Hefei Huayue New Material Technology Co., Ltd.; 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. WL-305 water-based polyurethane ink, solid content 35%, was purchased from Xiamen Kangdilong Trading Co., Ltd.

[0021] Example 1: A bio-based polyurethane water-based ink and its preparation process: S1: Preparation of waterborne polyurethane: S11: Add 20 parts of dehydrated diol (10 parts of polytetramethylene glycol, 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate and 80 parts of acetone into a reactor, and stir and heat to 80° C. under nitrogen protection to perform prepolymerization for 4 hours to obtain a polyurethane prepolymer with an isocyanate group mass fraction of 4.2%; S12: Under nitrogen protection, 16 parts of epoxidized soybean oil, 12.8 parts of anhydrous methanol, and 4.8 parts of NH 4 ZSM-5 molecular sieve and 20 parts of tetrahydrofuran were stirred and mixed evenly, and then heated to 120°C for 12 hours for ring-opening reaction. After the reaction system was naturally cooled to room temperature, it was filtered and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil; S13: (1) Under nitrogen protection, 5 parts of open-ring 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 then heated to 60°C, and 0.36 parts of ammonium persulfate were added to initiate polymerization for 4 hours to obtain modified epoxy soybean oil; S14: keeping the reaction temperature unchanged, adding 2.5 parts of ring-opened epoxy soybean oil and 2.5 parts of modified epoxy soybean oil to the polyurethane prepolymer, and carrying out 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 40wt%; S2: Preparation of modified starch: S21: Add hydrochloric acid solution to 20 parts of 45wt% 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; S22: Add 10 parts of product A and 7.5 parts of ring-opened epoxidized soybean oil into a reactor, stir and mix for 45 minutes, and then filter to obtain modified starch; 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 are mixed according to a proportion, and after shear emulsification treatment for 5 minutes, the mixture is allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0022] Example 2: A bio-based polyurethane water-based ink and its preparation process: S1: Preparation of waterborne polyurethane: S11: Add 20 parts of dehydrated diol (10 parts of polytetramethylene glycol, 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate and 80 parts of acetone into a reactor, and stir and heat to 80° C. under nitrogen protection to perform prepolymerization for 4 hours to obtain a polyurethane prepolymer with an isocyanate group mass fraction of 4.2%; S12: Under nitrogen protection, 16 parts of epoxidized soybean oil, 12.8 parts of anhydrous methanol, and 4.8 parts of NH 4 ZSM-5 molecular sieve and 20 parts of tetrahydrofuran were stirred and mixed evenly, and then heated to 120°C for 12 hours for ring-opening reaction. After the reaction system was naturally cooled to room temperature, it was filtered and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil; S13: (1) Under nitrogen protection, 5 parts of open-ring epoxy soybean oil, 0.8 parts of 2-butenoyl chloride and 0.008 parts of hydroquinone were added to a 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 then heated to 60°C, and 0.27 parts of ammonium persulfate were added to initiate polymerization for 4 hours to obtain modified epoxy soybean oil; S14: Keeping the reaction temperature unchanged, 1 part of ring-opened epoxy soybean oil and 1 part of modified epoxy soybean oil are added to the polyurethane prepolymer to carry out chain extension reaction for 3 hours; then the temperature is lowered to 40° C., triethylamine is added to adjust the pH to 7, and then an appropriate amount of deionized water is added, high-speed emulsification is performed for 2 hours, and finally vacuum distillation is performed to obtain a water-based polyurethane with a solid content of 40wt%; S2: Preparation of modified starch: S21: Add hydrochloric acid solution to 20 parts of 45wt% 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; S22: Add 10 parts of product A and 5 parts of ring-opened epoxidized soybean oil into the reactor, stir and mix for 45 minutes, and then filter to obtain modified starch; 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 are mixed according to a proportion, and after shear emulsification treatment for 5 minutes, the mixture is allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0023] Example 3: A bio-based polyurethane water-based ink and its preparation process: S1: Preparation of waterborne polyurethane: S11: Add 20 parts of dehydrated diol (10 parts of polytetramethylene glycol, 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate and 80 parts of acetone into a reactor, and stir and heat to 80° C. under nitrogen protection to perform prepolymerization for 4 hours to obtain a polyurethane prepolymer with an isocyanate group mass fraction of 4.2%; S12: Under nitrogen protection, add 20 parts of epoxidized soybean oil, 16 parts of anhydrous methanol, and 6 parts of NH 4 ZSM-5 molecular sieve and 20 parts of tetrahydrofuran were stirred and mixed evenly, and then heated to 120°C for 12 hours for ring-opening reaction. After the reaction system was naturally cooled to room temperature, it was filtered and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil; S13: (1) Under nitrogen protection, 5 parts of open-ring 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, heated to 60°C, and then 0.45 parts of ammonium persulfate were added to initiate polymerization for 4 hours to obtain modified epoxy soybean oil; S14: keeping the reaction temperature unchanged, adding 4 parts of ring-opened epoxy soybean oil and 4 parts of modified epoxy soybean oil to the polyurethane prepolymer, and carrying out 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 40wt%; S2: Preparation of modified starch: S21: Add hydrochloric acid solution to 20 parts of 45wt% 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; S22: Add 10 parts of product A and 10 parts of ring-opened epoxidized soybean oil into a reactor, stir and mix for 45 minutes, and then filter to obtain modified starch; 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 are mixed according to a proportion, and after shear emulsification treatment for 5 minutes, the mixture is allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0024] Based on Example 1, control experiments are set up below, specifically comparative examples 1 to 5, as described below: 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: A bio-based polyurethane water-based ink and its preparation process: S1: Preparation of waterborne polyurethane: S11: Add 20 parts of dehydrated diol (10 parts of polytetramethylene glycol, 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate and 80 parts of acetone into a reactor, and stir and heat to 80° C. under nitrogen protection to perform prepolymerization for 4 hours to obtain a polyurethane prepolymer with an isocyanate group mass fraction of 4.2%; S12: Under nitrogen protection, 16 parts of epoxidized soybean oil, 12.8 parts of anhydrous methanol, and 4.8 parts of NH 4 ZSM-5 molecular sieve and 20 parts of tetrahydrofuran were stirred and mixed evenly, and then heated to 120°C for 12 hours for ring-opening reaction. After the reaction system was naturally cooled to room temperature, it was filtered and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil; S13: keeping the reaction temperature constant, adding 5 parts of ring-opened epoxy soybean oil to the polyurethane prepolymer to carry out 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%; S2: Preparation of modified starch: S21: Add hydrochloric acid solution to 20 parts of 45wt% 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; S22: Add 10 parts of product A and 7.5 parts of ring-opened epoxidized soybean oil into a reactor, stir and mix for 45 minutes, and then filter to obtain modified starch; 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 are mixed according to a proportion, and after shear emulsification treatment for 5 minutes, the mixture is allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0025] Comparative Example 2: Comparative Example 2 is based on Example 1, with the following adjustments: no modification treatment is performed on the starch, and other processes remain unchanged, specifically: A bio-based polyurethane water-based ink and its preparation process: S1: Preparation of waterborne polyurethane: S11: Add 20 parts of dehydrated diol (10 parts of polytetramethylene glycol, 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate and 80 parts of acetone into a reactor, and stir and heat to 80° C. under nitrogen protection to perform prepolymerization for 4 hours to obtain a polyurethane prepolymer with an isocyanate group mass fraction of 4.2%; S12: Under nitrogen protection, 16 parts of epoxidized soybean oil, 12.8 parts of anhydrous methanol, and 4.8 parts of NH 4 ZSM-5 molecular sieve and 20 parts of tetrahydrofuran were stirred and mixed evenly, and then heated to 120°C for 12 hours for ring-opening reaction. After the reaction system was naturally cooled to room temperature, it was filtered and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil; S13: (1) Under nitrogen protection, 5 parts of open-ring 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 then heated to 60°C, and 0.36 parts of ammonium persulfate were added to initiate polymerization for 4 hours to obtain modified epoxy soybean oil; S14: keeping the reaction temperature unchanged, adding 2.5 parts of ring-opened epoxy soybean oil and 2.5 parts of modified epoxy soybean oil to the polyurethane prepolymer, and carrying out 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 40wt%; 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 are mixed according to a proportion, and after shear emulsification treatment for 5 minutes, the mixture is allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0026] 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: A bio-based polyurethane water-based ink and its preparation process: S1: Preparation of waterborne polyurethane: S11: Add 20 parts of dehydrated diol (10 parts of polytetramethylene glycol, 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate and 80 parts of acetone into a reactor, and stir and heat to 80° C. under nitrogen protection to perform prepolymerization for 4 hours to obtain a polyurethane prepolymer with an isocyanate group mass fraction of 4.2%; S12: Under nitrogen protection, 16 parts of epoxidized soybean oil, 12.8 parts of anhydrous methanol, and 4.8 parts of NH 4 ZSM-5 molecular sieve and 20 parts of tetrahydrofuran were stirred and mixed evenly, and then heated to 120°C for 12 hours for ring-opening reaction. After the reaction system was naturally cooled to room temperature, it was filtered and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil; S13: (1) Under nitrogen protection, 5 parts of open-ring 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 then heated to 60°C, and 0.36 parts of ammonium persulfate were added to initiate polymerization for 4 hours to obtain modified epoxy soybean oil; S14: keeping the reaction temperature unchanged, adding 2.5 parts of ring-opened epoxy soybean oil and 2.5 parts of modified epoxy soybean oil to the polyurethane prepolymer, and carrying out 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 40wt%; S2: Preparation of modified starch: 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; S22: Add 10 parts of product A and 7.5 parts of ring-opened epoxidized soybean oil into a reactor, stir and mix for 45 minutes, and then filter to obtain modified starch; 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 are mixed according to a proportion, and after shear emulsification treatment for 5 minutes, the mixture is allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0027] 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: A bio-based polyurethane water-based ink and its preparation process: S1: Preparation of waterborne polyurethane: S11: Add 20 parts of dehydrated diol (10 parts of polytetramethylene glycol, 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate and 80 parts of acetone into a reactor, and stir and heat to 80° C. under nitrogen protection to perform prepolymerization for 4 hours to obtain a polyurethane prepolymer with an isocyanate group mass fraction of 4.2%; S12: Under nitrogen protection, 16 parts of epoxidized soybean oil, 12.8 parts of anhydrous methanol, and 4.8 parts of NH 4 ZSM-5 molecular sieve and 20 parts of tetrahydrofuran were stirred and mixed evenly, and then heated to 120°C for 12 hours for ring-opening reaction. After the reaction system was naturally cooled to room temperature, it was filtered and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil; S13: (1) Under nitrogen protection, 5 parts of open-ring 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 then heated to 60°C, and 0.36 parts of ammonium persulfate were added to initiate polymerization for 4 hours to obtain modified epoxy soybean oil; S14: keeping the reaction temperature unchanged, adding 2.5 parts of ring-opened epoxy soybean oil and 2.5 parts of modified epoxy soybean oil to the polyurethane prepolymer, and carrying out 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 40wt%; S2: Preparation of modified starch: S21: adding hydrochloric acid solution to 20 parts of 45wt% starch suspension to adjust the pH to 5.5, stirring for 1.5 hours; then adding 17.5 parts of 3-amino-5-carboxyl-N-methylbenzamide and 0.35 parts of cyclohexanone peroxide thereto, stirring and heating to 110°C for reaction for 3 hours, filtering, washing and drying to obtain modified starch; 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 are mixed according to a proportion, and after shear emulsification treatment for 5 minutes, the mixture is allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0028] 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: A bio-based polyurethane water-based ink and its preparation process: S1: Preparation of waterborne polyurethane: S11: Add 20 parts of dehydrated diol (10 parts of polytetramethylene glycol, 10 parts of PEG-400), 14 parts of isophorone diisocyanate, 0.6 parts of dibutyltin dilaurate and 80 parts of acetone into a reactor, and stir and heat to 80° C. under nitrogen protection to perform prepolymerization for 4 hours to obtain a polyurethane prepolymer with an isocyanate group mass fraction of 4.2%; S12: Under nitrogen protection, 16 parts of epoxidized soybean oil, 12.8 parts of anhydrous methanol, and 4.8 parts of NH 4 ZSM-5 molecular sieve and 20 parts of tetrahydrofuran were stirred and mixed evenly, and then heated to 120°C for 12 hours for ring-opening reaction. After the reaction system was naturally cooled to room temperature, it was filtered and distilled under reduced pressure to obtain ring-opened epoxidized soybean oil; S13: (1) Under nitrogen protection, 5 parts of open-ring 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 then heated to 60°C, and 0.36 parts of ammonium persulfate were added to initiate polymerization for 4 hours to obtain modified epoxy soybean oil; S14: keeping the reaction temperature unchanged, adding 2.5 parts of ring-opened epoxy soybean oil and 2.5 parts of modified epoxy soybean oil to the polyurethane prepolymer, and carrying out 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 40wt%; S2: Preparation of modified starch: S21: Add hydrochloric acid solution to 20 parts of 45wt% 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; S22: Add 10 parts of product A and 7.5 parts of ring-opened epoxidized soybean oil into a reactor, stir and mix for 45 minutes, and then filter to obtain modified starch; 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 defoamer and 25 parts of deionized water are mixed according to a proportion, and after shear emulsification treatment for 5 minutes, the mixture is allowed to stand for defoaming to obtain a bio-based polyurethane water-based ink.

[0029] 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: (1) Thermal stability: After the ink on the surface of the PET film is dry, place it in 100°C water and boil it for 10 hours. After it cools down, observe whether the printed surface is wrinkled, ink is lost, or the printing is unclear; (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; (3) Gloss test: Ink gloss test is carried out according to the standard of GB / T 13217.2-2024; The results of the above tests are shown in Table 1 below: Table 1

[0030] Result analysis: From the data in Table 1 above, it can be seen that the present invention prepares a bio-based polyurethane water-based ink with excellent thermal stability, adhesion and printing quality by treating epoxidized soybean oil and starch. Comparing the commercially available water-based polyurethane ink with the ink prepared by the present invention, the ink prepared by the present invention has significantly improved related properties and shows significant practicality.

[0031] 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 present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A process for preparing a bio-based polyurethane water-based ink, characterized in that: 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 parts of dibutyltin dilaurate and 80 parts of acetone into a reaction kettle, stirring and heating to 70-85° C. under nitrogen protection, and performing prepolymerization for 1-6 hours to obtain a polyurethane prepolymer; S12: Keeping the reaction temperature unchanged, 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, high-speed emulsification is performed for 1-3 hours, and finally reduced pressure distillation is performed to obtain waterborne polyurethane; S2: Preparation of modified starch: S21: Add hydrochloric acid solution to 20 parts of 40-50wt% 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: adding 10 parts of product A and 5-10 parts of ring-opened epoxidized soybean oil into a reactor, stirring and mixing for 10-60 minutes, filtering, and modifying starch; 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.

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, characterized in that: 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, characterized in that: 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, characterized in that: 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 into a reaction kettle, after stirring and mixing evenly, the mixture is heated to 90 to 130° C., a ring-opening reaction is carried out for 6 to 24 hours, the reaction is terminated, and 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.

6. The process for preparing a bio-based polyurethane water-based ink according to claim 5, characterized in that: 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.

7. The process for preparing a bio-based polyurethane water-based ink according to claim 1, characterized in that: The modified epoxy soybean oil is obtained by modifying the ring-opened epoxy soybean oil. 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 an initiator are added to initiate polymerization for 1-6 hours to obtain the modified epoxy soybean oil.

8. 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.

9. The bio-based polyurethane water-based ink prepared by the preparation process of a bio-based polyurethane water-based ink according to any one of claims 1 to 8 is 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 parts of leveling agent, 1-2 parts of defoamer, and 20-30 parts of deionized water.

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