Environment-friendly bio-based self-coloring waterborne polyurethane ink and preparation method thereof
By grafting the phenolic hydroxyl group of the natural pigment curcumin onto the skeleton of castor oil-based water-based polyurethane, the defects in color uniformity and solvent resistance of the water-based ink are solved, and a self-colored water-based polyurethane ink is achieved, with better performance uniformity and environmental protection.
Patent Information
- Application Number
- CN202510389029.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2025-06-27
AI Technical Summary
Existing aqueous inks have defects in color uniformity and solvent resistance, and most colorants are carried out through simple physical mixing, resulting in uneven dispersion and easy migration.
The self-coloring of the aqueous polyurethane is achieved by grafting the phenolic hydroxyl group on the natural pigment curcumin onto the skeleton of the castor oil-based aqueous polyurethane and applied in the green environmentally friendly solvent water.
The self-coloring of water-based polyurethane is achieved, solving the problems of uneven color and easy migration, improving the uniformity and life of the ink, and has the advantages of environmental protection and degradability.
Smart Images
Figure CN120209629A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of inks, and specifically relates to an environmentally friendly bio-based self-coloring waterborne polyurethane ink and a preparation method thereof. Background Art
[0002] Nowadays, with the rapid development of the ink industry, conventional oil-based inks contain a large amount of volatile organic compounds (VOCs), which can cause environmental pollution and pose a threat to human health. As a result, waterborne inks have gradually become an important development direction in the ink industry because waterborne inks use water as a solvent and have excellent environmental friendliness and printing suitability. Among them, water-based color inks are widely used in the printing field due to their low carbon, non-toxic, simple production, recyclable and other advantages. However, currently most color inks are simply physically mixed with color substances and other components, resulting in disadvantages such as uneven color, easy migration, easy to wash off, and solvent intolerance. Therefore, grafting color groups onto the polymer backbone is one of the effective methods to avoid the above problems.
[0003] Currently, solvent-based materials are mostly used in inks. Compared with solvent-based polyurethanes, waterborne polyurethanes use water as a solvent and are more environmentally friendly while maintaining excellent molecular designability, mechanical properties, wear resistance, acid and alkali resistance and other application properties of polyurethanes. Therefore, waterborne polyurethanes can be used as a binder component of waterborne inks. However, the main component of synthetic waterborne polyurethanes is polyol, and most of them come from petroleum-based resources. With the rising price of petroleum resources, the increasing depletion of petroleum resources and the requirements of environmental protection, more and more sustainable resource plant-based polyols have begun to be used to replace petroleum-based resources, including bio-based materials such as cellulose, lignin, starch, vegetable oil, etc., so as to synthesize a new generation of bio-based polyurethanes with rich resources, renewable, biodegradable, non-toxic or low-toxic and low price. However, there are few reports on how to obtain self-coloring waterborne polyurethanes. Summary of the Invention
[0004] The purpose of the present invention is to provide an environmentally friendly bio-based self-coloring waterborne polyurethane ink and a preparation method thereof. By grafting the phenolic hydroxyl groups at both ends of natural pigment curcumin onto the backbone of natural substance castor oil-based waterborne polyurethane, the waterborne polyurethane can be self-colored and the water-insoluble curcumin can be applied in the green and environmentally friendly solvent water.
[0005] The purpose of the present invention can be achieved by the following technical solutions:
[0006] A preparation method of an environmentally friendly bio-based self-coloring waterborne polyurethane ink, comprising the following steps:
[0007] Step 1: Prepare a castor oil-based prepolymer:
[0008] Step 1.1: Add isophorone diisocyanate and 2,2-dimethylolpropionic acid into a reaction vessel and react for a period of time at a certain temperature.
[0009] Step 1.2: Add a certain amount of natural substance castor oil and react for a period of time to obtain a castor oil-based prepolymer.
[0010] Step 2: Preparation of bio-based self-coloring waterborne polyurethane binder:
[0011] Step 2.1: Add a certain amount of natural pigment curcumin as a chain extender to the castor oil-based prepolymer synthesized in Step 1 and react for a period of time.
[0012] Step 2.2: Then add triethylamine and react for a period of time, and then add a certain amount of deionized water to obtain a bio-based self-coloring waterborne polyurethane binder.
[0013] Step 3: Mix the bio-based self-coloring waterborne polyurethane binder, thickener, leveling agent, defoamer, solvent and other additives in proportion to finally obtain a bio-based self-coloring waterborne polyurethane ink.
[0014] Further, the reaction temperature in Step 1.1 is 50 - 80 °C, and the reaction time is 30 min - 60 min.
[0015] Further, in Step 1.2, add 30% - 50% by mass of natural substance castor oil and react for 90 min - 180 min to obtain a castor oil-based prepolymer.
[0016] Further, in Step 2.1, add 0% - 10% by mass of natural substance curcumin as a chain extender to the castor oil-based prepolymer and react for 180 min - 300 min.
[0017] Further, in Step 2.2, add triethylamine and react for 30 min, and then add 60% - 80% by mass of deionized water to obtain a bio-based self-coloring waterborne polyurethane binder.
[0018] Further, in Step 3, by mass percentage, the proportions of each raw material are: 65% - 80% of bio-based self-coloring waterborne polyurethane binder, 0.6% - 1.2% of thickener, 1% - 1.5% of leveling agent, 3% - 5% of defoamer, 18% - 22% of solvent and other additives.
[0019] Another object of the present invention is to provide an environmentally friendly bio-based self-coloring waterborne polyurethane ink prepared by the above method.
[0020] Advantages of the present invention:
[0021] (1) In the present invention, the phenolic hydroxyl groups at both ends of the natural pigment curcumin are grafted onto the backbone of the natural substance castor oil-based waterborne polyurethane, enabling the waterborne polyurethane to be self-colored and making the water-insoluble curcumin applicable in the green and environmentally friendly solvent water. The obtained bio-based self-colored waterborne polyurethane ink has the advantages of simple preparation, low cost, degradability, environmental friendliness, etc.
[0022] (2) The present invention uses the natural pigment curcumin grafted onto the polymer backbone to solve the disadvantages such as uneven dispersion and easy migration caused by the simple physical mixing of most colorants. The performance uniformity and lifespan of the ink are improved. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The present invention will be further described below with reference to the accompanying drawings.
[0024] Figure 1 It is a comparative diagram of the screen printing effects of the environmentally friendly bio-based self-colored waterborne polyurethane inks prepared for Example 1 (A), Example 2 (B), Example 3 (C), and Example 4 (D).
[0025] Figure 2 It is a comparative diagram of the environmentally friendly bio-based self-colored waterborne polyurethane ink prepared in Example 4 after being screen printed on the fabric and placed for 180 days. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.
[0027] Example 1
[0028] First, isophorone diisocyanate and 2,2-dimethylolpropionic acid are added to a reaction vessel and reacted at a temperature of 50 °C for 30 min. Then, natural substance castor oil with a mass fraction of 40% is added and reacted for 90 min to obtain a castor oil-based prepolymer. 3% of the natural pigment curcumin (Cur) by mass fraction is added to the synthesized prepolymer as a chain extender and reacted for 180 min. Then, triethylamine is added and reacted for 30 min, and then deionized water with a mass fraction of 70% is added. Then, it is shear-emulsified by a mechanical stirrer at 2000 rpm to obtain a bio-based waterborne polyurethane emulsion. Then, 76% of the bio-based waterborne polyurethane binder, 0.8% of the defoamer, 1.2% of the leveling agent, 2% of the thickener, 18% of ethanol, and 0.5% of the dryer are stirred to prepare an environmentally friendly bio-based self-colored waterborne polyurethane ink.
[0029] Example 2
[0030] First, isophorone diisocyanate and 2,2-dimethylolpropionic acid were added to a reaction vessel and reacted at 50 °C for 30 min. Then, castor oil with a mass fraction of 40% was added and reacted for 90 min to obtain a castor oil-based prepolymer. To the synthesized prepolymer, 3% by mass of the natural pigment curcumin (Cur) was added as a chain extender and reacted for 180 min. Then, triethylamine was added and reacted for 30 min, followed by the addition of 70% by mass of deionized water. Then, it was shear-emulsified with a mechanical stirrer at 2000 rpm to obtain a bio-based waterborne polyurethane emulsion. Then, 76% of the bio-based waterborne polyurethane binder, 0.8% of the defoamer, 1.2% of the leveling agent, 2.5% of the thickener, 18% of ethanol, and 0.5% of the drier were stirred to prepare an environmentally friendly bio-based self-coloring waterborne polyurethane ink.
[0031] Example 3
[0032] First, isophorone diisocyanate and 2,2-dimethylolpropionic acid were added to a reaction vessel and reacted at 50 °C for 30 min. Then, castor oil with a mass fraction of 40% was added and reacted for 90 min to obtain a castor oil-based prepolymer. To the synthesized prepolymer, 3% by mass of the natural pigment curcumin (Cur) was added as a chain extender and reacted for 180 min. Then, triethylamine was added and reacted for 30 min, followed by the addition of 70% by mass of deionized water. Then, it was shear-emulsified with a mechanical stirrer at 2000 rpm to obtain a bio-based waterborne polyurethane emulsion. Then, 76% of the bio-based waterborne polyurethane binder, 0.8% of the defoamer, 1.2% of the leveling agent, 3% of the thickener, 18% of ethanol, and 0.5% of the drier were stirred to prepare an environmentally friendly bio-based self-coloring waterborne polyurethane ink.
[0033] Example 4
[0034] First, isophorone diisocyanate and 2,2-dimethylolpropionic acid were added to a reaction vessel and reacted at 50 °C for 30 min. Then, castor oil with a mass fraction of 40% was added and reacted for 90 min to obtain a castor oil-based prepolymer. To the synthesized prepolymer, 3% by mass of the natural substance curcumin (Cur) was added as a chain extender and reacted for 180 min. Then, triethylamine was added and reacted for 30 min, followed by the addition of 70% by mass of deionized water. Then, it was shear-emulsified with a mechanical stirrer at 2000 rpm to obtain a bio-based waterborne polyurethane emulsion. Then, 76% of the bio-based waterborne polyurethane binder, 0.8% of the defoamer, 1.2% of the leveling agent, 4% of the thickener, 18% of the solvent, and 0.5% of the drier were stirred to prepare an environmentally friendly bio-based self-coloring waterborne polyurethane ink.
[0035] Figure 1Comparison chart of the screen printing effects of the environmentally friendly bio-based self-coloring waterborne polyurethane ink prepared in Example 1, Example 2, Example 3 and Example 4. As can be seen from the figure, the printed pattern of the environmentally friendly bio-based self-coloring waterborne polyurethane ink shows yellow. As the amount of thickener added increases, the printed pattern becomes clearer and smoother, indicating that the environmentally friendly bio-based self-coloring ink has good printing adaptability.
[0036] Figure 2 It is a comparison chart of the environmentally friendly bio-based self-coloring waterborne polyurethane ink prepared in Example 4 after being screen-printed on the fabric and placed for 180 days. As can be clearly observed from the figure, after 180 days of natural aging test, the clothing pattern printed with the castor oil-based waterborne ink still maintains good color saturation and clarity. This indicates that the ink has excellent durability and stability.
[0037] The above specific implementation part has specifically introduced the analysis method involved in the present invention. It should be noted that the above introduction is only to help those skilled in the art better understand the method and idea of the present invention, rather than a limitation on the relevant content. Without departing from the principle of the present invention, those skilled in the art can also make appropriate adjustments or modifications to the present invention, and the above adjustments and modifications should also fall within the protection scope of the present invention.
Claims
1. A method for preparing an environmentally friendly bio-based self-coloring water-based polyurethane ink, characterized in that: The following steps are involved: Step 1: Preparation of castor oil-based prepolymer: Step 1.1: adding isophorone diisocyanate and 2,2-dimethylol propionic acid into a reaction vessel and reacting them at a certain temperature for a period of time; Step 1.2: adding a certain amount of natural substance castor oil and reacting for a period of time to obtain castor oil-based prepolymer; Step 2: Preparation of bio-based self-coloring waterborne polyurethane binder: Step 2.1: adding a certain amount of natural pigment curcumin as a chain extender to the castor oil-based prepolymer synthesized in step 1 and reacting for a period of time; Step 2.2: Then, triethylamine is added to react for a period of time, and then a certain amount of deionized water is added to obtain a bio-based self-coloring waterborne polyurethane connecting material; Step 3: Mix the bio-based self-coloring water-based polyurethane binder, thickener, leveling agent, defoamer, solvent and other additives in proportion to finally obtain the bio-based self-coloring water-based polyurethane ink.
2. The method for preparing an environmentally friendly bio-based self-coloring water-based polyurethane ink according to claim 1, characterized in that: The reaction temperature in step 1.1 is 50-80°C, and the reaction time is 30min-60min.
3. The method for preparing an environmentally friendly bio-based self-coloring water-based polyurethane ink according to claim 1, characterized in that: In step 1.2, 30% to 50% by mass of natural substance castor oil is added and reacted for 90 min to 180 min to obtain a castor oil-based prepolymer.
4. The method for preparing an environmentally friendly bio-based self-coloring water-based polyurethane ink according to claim 1, characterized in that: In step 2.1, 0% to 10% by mass of natural substance curcumin is added to the castor oil-based prepolymer as a chain extender, and the reaction is carried out for 180 min to 300 min.
5. The method for preparing an environmentally friendly bio-based self-coloring water-based polyurethane ink according to claim 1, characterized in that: In step 2.2, triethylamine is added and reacted for 30 minutes, and then deionized water with a mass fraction of 60%-80% is added to obtain a bio-based self-coloring waterborne polyurethane connecting material.
6. The method for preparing an environmentally friendly bio-based self-coloring water-based polyurethane ink according to claim 1, characterized in that: In step 3, the proportions of various raw materials are as follows, by mass percentage: 65%-80% of bio-based self-coloring waterborne polyurethane binder, 0.6%-1.2% of thickener, 1%-1.5% of leveling agent, 3%-5% of defoamer, 18%-22% of solvent and other additives.
7. An environmentally friendly bio-based self-coloring water-based polyurethane ink, characterized in that: Prepared according to the method according to any one of claims 1 to 6.