Bio-based waterborne polyurethane emulsion as well as preparation method and application thereof

Abstract

The invention provides a bio-based waterborne polyurethane emulsion. The bio-based waterborne polyurethane emulsion is prepared from raw materials and deionized water, the raw materials comprise a first component and a second component; the first component comprises bio-based polyol, isocyanate, a siloxane chain extender, a small molecule chain extender, a hydrophilic chain extender, a cross-linking agent, a polyamine chain extender and a neutralizer; based on the mass of the first component, the bio-based polyol accounts for 40 wt%-50 wt%, the isocyanate accounts for 30 wt%-40 wt%, the siloxane chain extender accounts for 2 wt%-5 wt%, the micromolecule chain extender accounts for 2 wt%-6 wt%, the hydrophilic chain extender accounts for 4 wt%-6 wt%, the cross-linking agent accounts for 0.5 wt%-2 wt%, the polyamine chain extender accounts for 2 wt%-6 wt%, and the neutralizer accounts for 3 wt%-5 wt%; the second component comprises a catalyst, and based on the mass of the first component, the catalyst accounts for 0.1 wt%-0.5 wt%; the siloxane chain extender is selected from single-ended dihydroxy polydimethylsiloxane; the hydrophilic chain extender comprises a dicarboxylic acid hydrophilic monomer and a binary sulfonic acid hydrophilic monomer; the solid content of the bio-based waterborne polyurethane emulsion is 45wt%-53wt%. The bio-based waterborne polyurethane emulsion provided by the invention has high bio-based content and high solid content, and also has high water resistance, smoothness and fatigue tolerance.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of polyurethane materials, in particular to a bio-based waterborne polyurethane emulsion and a preparation method and application thereof. BACKGROUND

[0002] As an environmentally friendly material, the waterborne polyurethane gradually replaces the formaldehyde-containing acrylic resin in the printing glue field. High bio-based content and high solid content waterborne polyurethane become the mainstream trend. However, the existing products have bottlenecks in water resistance, smoothness and cost in three dimensions, which restrict their application in high-end textile printing. First, most bio-based polyols contain hydrophilic ester bonds, which leads to water swelling of the glue film and reduces the wash fastness of printing. It is necessary to block the penetration path of water molecules while retaining the bio-based structure. Second, high solid content emulsion needs rigid segments to maintain stability, but rigid groups hinder molecular chain movement, sacrificing the soft touch feeling required by fabrics. Finally, in order to improve the smoothness, silicone / nano materials are added, which requires complex compounding process, and the dispersion stability of nano particles is poor, resulting in increased production cost. Therefore, it is urgent to develop a new bio-based waterborne polyurethane emulsion. SUMMARY

[0003] The application aims to provide a bio-based waterborne polyurethane emulsion and a preparation method and application thereof, so as to realize high bio-based content and high solid content, and also have high water resistance, smoothness and wear resistance. The specific technical scheme is as follows:

[0004] The first aspect of the application provides a bio-based waterborne polyurethane emulsion, which comprises raw materials and deionized water; wherein the raw materials comprise a first component and a second component; the first component comprises bio-based polyol, isocyanate, siloxane chain extender, small molecule chain extender, hydrophilic chain extender, crosslinking agent, polyamine chain extender and neutralizing agent; based on the mass of the first component, the bio-based polyol is 40wt%-50wt%, the isocyanate is 30wt%-40wt%, the siloxane chain extender is 2wt%-5wt%, the small molecule chain extender is 2wt%-6wt%, the hydrophilic chain extender is 4wt%-6wt%, the crosslinking agent is 0.5wt%-2wt%, the polyamine chain extender is 2wt%-6wt%, and the neutralizing agent is 3wt%-5wt%; the second component comprises a catalyst, and the catalyst is 0.1wt%-0.5wt% based on the mass of the first component; the siloxane chain extender is selected from mono-end dihydroxy polydimethylsiloxane; the hydrophilic chain extender comprises a dibasic carboxylic acid hydrophilic monomer and a dibasic sulfonic acid hydrophilic monomer; and the solid content of the bio-based waterborne polyurethane emulsion is 45wt%-53wt%.

[0005] In an embodiment of the present application, the bio-based polyol is selected from at least one of polytrimethylene ether glycol and polycarbonate glycol; preferably, the polytrimethylene ether glycol has a number average molecular weight of 600-3000, and the polycarbonate glycol has a number average molecular weight of 1000-2000.

[0006] In an embodiment of the present application, the isocyanate is selected from diisocyanate; preferably, the isocyanate is selected from at least one of isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), diphenylmethane diisocyanate (MDI) and toluene diisocyanate (TDI).

[0007] In an embodiment of the present application, the mono-end dihydroxyl polydimethylsiloxane has a number average molecular weight of 1000-3000.

[0008] In an embodiment of the present application, the small molecule chain extender is selected from at least one of 1,4-butanediol (BDO), 1,6-hexanediol, propylene glycol and pentanediol.

[0009] In an embodiment of the present application, the dicarboxylic acid hydrophilic monomer is selected from at least one of 2,2-dimethylol propionic acid, 2,2-dimethylol butyric acid and 3,5-dihydroxy-3-methyl valeric acid; the disulfonic acid hydrophilic monomer is selected from 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt.

[0010] In an embodiment of the present application, the catalyst is selected from at least one of bismuth neodecanoate and bismuth iso-octoate.

[0011] In an embodiment of the present application, the crosslinking agent is selected from at least one of castor oil and trimethylolpropane.

[0012] In an embodiment of the present application, the polyamine chain extender is selected from at least one of organic primary amine containing two active hydrogens, inorganic primary amine containing two active hydrogens, organic secondary amine containing two active hydrogens and inorganic secondary amine containing two active hydrogens; preferably, the polyamine chain extender is selected from at least one of ethylenediamine, isophorone diamine, hexamethylenediamine, diethylenetriamine, phenylenediamine, toluenediamine and dicyclohexylmethane diamine.

[0013] In an embodiment of the present application, the neutralizing agent is selected from at least one of triethylamine, ammonia and triethanolamine.

[0014] The second aspect of the present application provides a preparation method of the bio-based waterborne polyurethane emulsion according to the first aspect of the present application, which comprises:

[0015] (1) Put the bio-based polyol into the reaction device, heat to 110-115°C, and vacuum dehydrate for 3-4 hours;

[0016] (2) Cool to 50-70°C, add isocyanate, heat to 70-80°C, and react for 2-3 hours;

[0017] (3) Cool to 50-60°C, add siloxane chain extender, small molecule chain extender, catalyst, organic solvent, crosslinking agent, and dicarboxylic acid hydrophilic monomer, and control the temperature at 50-60°C to react for 3-5 hours;

[0018] (4) Cool to 30-40°C, add dicarboxylic acid hydrophilic monomer, control the temperature at 30-40°C, and react for 30-60 minutes to obtain a prepolymer;

[0019] (5) Move the prepolymer into a dispersion device, control the temperature at 35-40°C, add a neutralizing agent and neutralize for 30-40 minutes, disperse with deionized water at high speed, add a polyamine chain extender, and further react for 10-60 minutes to obtain a dispersion;

[0020] (6) Move the dispersion into a reduced pressure device, control the temperature at 25-75°C, remove the organic solvent, and obtain the bio-based waterborne polyurethane emulsion.

[0021] The third aspect of the present application provides an application of the bio-based waterborne polyurethane emulsion of the first aspect of the present application or the bio-based waterborne polyurethane emulsion prepared by the preparation method of the second aspect of the present application in printing glue.

[0022] The beneficial effects of the present application are as follows:

[0023] The application realizes the high-efficiency synergy of the two in the waterborne polyurethane through the molecular design of the bio-based polyol and the mono-end double-hydroxyl polydimethylsiloxane. Specifically, the selected bio-based polyol (such as polycarbonate diol or polytrimethylene ether diol) overcomes the shortcoming of traditional ester groups that easily lead to high water absorption by means of hydrolysis-resistant carbonate bonds or ether bonds from the polymer main chain level, ensuring the basis of body water resistance and durability under high bio-based content. At the same time, the introduced mono-end double-hydroxyl polydimethylsiloxane as a “suspended type” modifier can spontaneously migrate to the coating surface during the drying and film forming process, and has higher water resistance than general siloxane chain extenders, which not only significantly reduces the water absorption rate of the film, but also directly improves the smoothness by reducing the roughness caused by particle indentation. The synergy of the two lies in that the bio-based polyol constructs a strong and water-resistant body skeleton, and the siloxane provides active surface hydrophobicity and smoothness, thereby achieving the unity of “body strengthening” and “surface optimization” at the molecular level. The synergistic effect ultimately enables the waterborne polyurethane emulsion to achieve high bio-based content and high solid content while comprehensively obtaining excellent water resistance, smoothness and durability, breaking through the technical bottleneck that high bio-based content and high performance are difficult to be achieved in traditional materials, and greatly maintaining the smoothness of the printed layer. Further, the raw material selection and component content of the bio-based waterborne polyurethane emulsion of the application are selected through experiments, and the bio-based waterborne polyurethane emulsion obtained has high bio-based content, high solid content, high water resistance, smoothness and durability.

[0024] The application also provides a preparation method of a bio-based waterborne polyurethane emulsion. The bio-based waterborne polyurethane emulsion prepared by the preparation method of the application has high bio-based content, high solid content, higher water resistance, smoothness and durability.

[0025] The bio-based waterborne polyurethane emulsion of the application has high bio-based content, high solid content, high water resistance, smoothness and durability, and can be better applied to textile printing.

[0026] Of course, implementing any product or method of the application does not necessarily require all the advantages described above. DETAILED DESCRIPTION

[0027] The technical solutions in the application will be described below in conjunction with the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, not all embodiments. All other embodiments obtained by those skilled in the art based on the application belong to the scope of protection of the application.

[0028] The first aspect of this application provides a bio-based aqueous polyurethane emulsion, comprising raw materials and deionized water; wherein the raw materials comprise a first component and a second component; the first component comprises a bio-based polyol, isocyanate, siloxane chain extender, small molecule chain extender, hydrophilic chain extender, crosslinking agent, polyamine chain extender, and neutralizing agent; based on the mass of the first component, the bio-based polyol is 40wt%~50wt%, the isocyanate is 30wt%~40wt%, the siloxane chain extender is 2wt%~5wt%, and the small molecule chain extender is 2wt%~6wt%. The first component comprises 4wt% to 6wt% of the hydrophilic chain extender, 0.5wt% to 2wt% of the crosslinking agent, 2wt% to 6wt% of the polyamine chain extender, and 3wt% to 5wt% of the neutralizing agent; the second component includes a catalyst, which is 0.1wt% to 0.5wt% based on the mass of the first component; the siloxane chain extender is selected from mono-terminated dihydroxy polydimethylsiloxane; the hydrophilic chain extender includes dicarboxylic acid hydrophilic monomers and disulfonic acid hydrophilic monomers; the solid content of the bio-based waterborne polyurethane emulsion is 45wt% to 53wt%.

[0029] For example, based on the mass of the first component, the content of the bio-based polyol can be 40wt%, 45wt%, 50wt%, or any two of these values; the content of the isocyanate can be 30wt%, 35wt%, 40wt%, or any two of these values; the content of the siloxane chain extender can be 2wt%, 3wt%, 4wt%, 5wt%, or any two of these values; the content of the small molecule chain extender can be 2wt%, 4wt%, 6wt%, or any two of these values; the content of the hydrophilic chain extender can be 4wt%, 5wt%, 6wt%, or any two of these values; the content of the crosslinking agent can be 0.5wt%, 1wt%, 2wt%, or any two of these values; the content of the polyamine chain extender can be 2wt%, 4wt%, 6wt%, or any two of these values; and the content of the neutralizing agent can be 3wt%, 4wt%, 5wt%, or any two of these values. Based on the mass of the first component, the catalyst content can be 0.1 wt%, 0.3 wt%, 0.5 wt%, or a range of any two of these values. The solid content of the bio-based aqueous polyurethane emulsion can be 45 wt%, 48 wt%, 50 wt%, 53 wt%, or a range of any two of these values. It should be noted that the solid content of the bio-based aqueous polyurethane emulsion = (mass of raw materials / total mass of the bio-based aqueous polyurethane emulsion) × 100%.

[0030] This application does not impose any particular limitation on the content of the dicarboxylic acid hydrophilic monomer and the disulfonic acid hydrophilic monomer in the raw material, as long as the purpose of this application can be achieved. For example, in the raw material, the dicarboxylic acid hydrophilic monomer is 2wt%~5wt%, and the disulfonic acid hydrophilic monomer is 1wt%~3wt%.

[0031] In this application, the amount of deionized water is not specifically limited, as long as it can achieve the purpose of this application. For example, it can be adaptively adjusted according to the solid content of the target product bio-based waterborne polyurethane emulsion and the experimental method to achieve the purpose of this application.

[0032] The study found that single-terminated dihydroxyl polydimethylsiloxane (SDM) is a suspended type in polyurethane, which can diffuse to the film surface during drying, resulting in higher hydrophobicity and better reduction of roughness caused by particle indentation, thereby improving the smoothness. The introduction of a smooth-feeling SDM reduces the film's water absorption rate, maintaining the smoothness of the printed layer to a great extent while meeting the requirements of high solids content and high bio-based content. In summary, the bio-based waterborne polyurethane emulsion of this application uses raw materials and component contents within the above-mentioned ranges, resulting in a bio-based waterborne polyurethane emulsion that possesses high bio-based content and high solids content, as well as high water resistance, smoothness, and durability.

[0033] In one embodiment of this application, the bio-based polyol is selected from at least one of polytrimethylene ether glycol and polycarbonate glycol; preferably, the number-average molecular weight of the polytrimethylene ether glycol is 600 to 3000, for example, the number-average molecular weight of the polytrimethylene ether glycol can be 600, 1000, 1500, 2000, 2500, 3000 or any two of these values; the number-average molecular weight of the polycarbonate glycol is 1000 to 2000, for example, the number-average molecular weight of the polycarbonate glycol can be 1000, 1500, 2000 or any two of these values.

[0034] In one embodiment of this application, the bio-based polyol has a bio-based content of 72% to 100%. For example, the bio-based content of polycarbonate diol is 72% (Mofltive HBE), and the bio-based content of polytrimethylene ether diol is 100% (PO3G). Studies have found that excessively high bio-based polyol content leads to higher water absorption and reduced washability, often due to the excessive use of hydrophilic ester groups in traditional bio-based polyols. The bio-based polyol of this application mitigates this drawback by using hydrolysis-resistant carbonate bonds (e.g., polycarbonate diol) or by not using ester groups (e.g., polytrimethylene ether diol), resulting in a bio-based waterborne polyurethane emulsion with high bio-based content and good washability.

[0035] In one embodiment of this application, the isocyanate is selected from diisocyanates; preferably, the isocyanate is selected from at least one of isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate and toluene diisocyanate.

[0036] In one embodiment of this application, the number-average molecular weight of the single-terminated dihydroxyl polydimethylsiloxane is 1000-3000. For example, the number-average molecular weight of the single-terminated dihydroxyl polydimethylsiloxane can be 1000, 2000, 3000, or a range consisting of any two of these values. For example, the single-terminated dihydroxyl polydimethylsiloxane is shown in the following structural formula, where m depends on the number-average molecular weight of the single-terminated dihydroxyl polydimethylsiloxane.

[0037]

[0038] In one embodiment of this application, the small molecule chain extender is selected from at least one of 1,4-butanediol, 1,6-hexanediol, propylene glycol, and pentanediol.

[0039] In one embodiment of this application, the dicarboxylic acid hydrophilic monomer is selected from at least one of 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid and 3,5-dihydroxy-3-methylvaleric acid; the disulfonic acid hydrophilic monomer is selected from sodium 2-[(2-aminoethyl)amino]ethanesulfonate.

[0040] In one embodiment of this application, the catalyst is selected from at least one of bismuth neodecanoate and bismuth isooctanoate.

[0041] In one embodiment of this application, the crosslinking agent is selected from at least one of castor oil and trimethylolpropane.

[0042] In one embodiment of this application, the polyamine chain extender is selected from at least one of an organic primary amine containing two active hydrogens, an inorganic primary amine containing two active hydrogens, an organic secondary amine containing two active hydrogens, and an inorganic secondary amine containing two active hydrogens; preferably, the polyamine chain extender is selected from at least one of ethylenediamine, isophorone diamine, hexamethylenediamine, diethylenetriamine, phenylenediamine, toluenediamine, and dicyclohexylmethanediamine.

[0043] In one embodiment of this application, the neutralizing agent is selected from at least one of triethylamine, ammonia, and triethanolamine.

[0044] A second aspect of this application provides a method for preparing a bio-based aqueous polyurethane emulsion according to the first aspect of this application, comprising:

[0045] (1) Add the bio-based polyol into the reaction apparatus, heat it to 110℃~115℃, and dehydrate it under vacuum for 3~4 hours;

[0046] (2) Cool down to 50℃~70℃, add isocyanate, and heat up to 70℃~80℃ to react for 2~3 hours;

[0047] (3) Cool down to 50℃~60℃, add siloxane chain extender, small molecule chain extender, catalyst, organic solvent, crosslinking agent, and dicarboxylic acid hydrophilic monomer, and control the temperature at 50℃~60℃ for 3~5 hours.

[0048] (4) Cool down to 30℃~40℃, add disulfonic acid hydrophilic monomer, and react at 30℃~40℃ for 30~60 minutes to obtain prepolymer;

[0049] (5) The prepolymer is transferred into a dispersion device at a temperature of 35°C to 40°C. A neutralizing agent is added and the mixture is neutralized for 30 to 40 minutes. The mixture is then dispersed at high speed with deionized water. A polyamine chain extender is added and the mixture is reacted for another 10 to 60 minutes to obtain the dispersion.

[0050] (6) The dispersion is transferred into a vacuum device and the temperature is controlled at 25°C to 75°C to remove the organic solvent and obtain the bio-based waterborne polyurethane emulsion.

[0051] In one embodiment of this application, the organic solvent is selected from at least one of acetone and butanone. This application does not specifically limit the exact content of the organic solvent; for example, based on the raw material as 100 wt%, the amount of acetone used is 20 wt% to 40 wt%.

[0052] This application does not impose any particular limitations on the above-mentioned reaction apparatus, dispersion apparatus, and depressurization apparatus, as long as they can achieve the purpose of this application.

[0053] This application does not impose any particular limitation on the specific method of high-speed dispersion, as long as it can achieve the purpose of this application, such as dispersion at a speed of 1500~2000 rpm for 25~30 minutes.

[0054] The bio-based waterborne polyurethane emulsion prepared by the method described in this application possesses high bio-based content and high solids content, while also exhibiting high water resistance, a smooth feel, and durability. Specifically, the study found that the solubility parameters of polysiloxane and polyurethane differ significantly. Modification methods such as simple blending and in-situ polymerization to prepare interpenetrating polymer networks yielded unsatisfactory results. The method described in this application introduces a smooth-feeling, single-terminated dihydroxyl polydimethylsiloxane, reducing the film's water absorption rate. This not only satisfies the requirements of high solids content and high bio-based content but also greatly maintains the smooth feel of the printed layer.

[0055] The third aspect of this application provides the application of the bio-based waterborne polyurethane emulsion described in the first aspect of this application or the bio-based waterborne polyurethane emulsion prepared by the preparation method described in the second aspect of this application in printing adhesives.

[0056] The bio-based waterborne polyurethane emulsion of this application is used in printing adhesives. Compared with traditional waterborne polyurethane, it has a higher bio-based content, which can meet higher specifications in terms of environmental protection and sustainable development. At the same time, it has a higher effective ingredient content, which can reduce the number of printing steps in screen printing and achieve efficient printing. In addition, the bio-based waterborne polyurethane emulsion of this application introduces a slip-resistant single-terminated dihydroxy polydimethylsiloxane, which reduces the water absorption rate of the film. It not only meets the requirements of high solid content and high bio-based content, but also maintains the smoothness of the printing layer to a great extent.

[0057] Example

[0058] The embodiments and comparative examples provided below illustrate the implementation of this application in more detail. Various tests and evaluations were conducted according to the methods described below. Furthermore, unless otherwise specified, "parts" and "%" are quality standards.

[0059] Test methods and equipment:

[0060] The bio-based waterborne polyurethane emulsion prepared using the examples and comparative examples was mixed with propylene glycol and waterborne acrylic acid to obtain a waterborne paste. Printed samples were prepared using a manual screen printing method, with four coats applied after each application of the waterborne paste, for a total of two coats. The printed samples were cured in a 50°C oven for 24 hours before the printing performance was tested. The formulation of the waterborne paste is as follows:

[0061]

[0062] Determination of solid content: Vacuum drying method (moisture determination): Use a 3mL pipette to take 1g of sample into a tray, accurately record the value, place it in a vacuum drying oven, set the temperature to 110℃, and take it out every 5 minutes to record the value. If the value remains unchanged for two consecutive times, the drying is considered complete. Solid content = mass after drying / mass before drying × 100%.

[0063] Particle size testing: Malvern particle size analyzer was used in accordance with GB / T 19077-2016.

[0064] Water absorption test: Weigh using an analytical balance. Take a certain amount of bio-based waterborne polyurethane emulsion into a tray, dry it to form a film, and cut it into 1cm × 1cm (2mm thick) polyurethane film sheets. Place the polyurethane film sheets in water at 25℃ and test at a constant temperature for 24 hours. Remove the polyurethane film sheets, wipe off the surface moisture, and weigh them. The percentage difference is the water absorption rate.

[0065] Colorfastness to rubbing test: Determined according to GB / T3920-2008 "Textiles - Tests for colorfastness - Colorfastness to rubbing". It is divided into 5 grades, from grade 1 to grade 5, where grade 1 is the worst and grade 5 is the best. The colorfastness of a sample may also fall between adjacent grades, which can be expressed as grade m-m+1, indicating that the colorfastness is between grade m and grade m+1. For example, grade 4-5 means that the colorfastness is between grade 4 and grade 5.

[0066] Smoothness Test: Ten people were randomly selected to rate the printed samples in turn, and the average score was taken. A total of five levels were assigned, from Level 1 to Level 5, with Level 1 being the worst and Level 5 the best. The smoothness of a sample may fall between adjacent levels, represented as Level m-m+1, indicating that the smoothness is between Level m and Level m+1. For example, Level 4-5 means the smoothness is between Level 4 and Level 5.

[0067] Example 1

[0068] A bio-based aqueous polyurethane emulsion comprises a first component and a second component, wherein the first component is shown in the table below, and the second component is bismuth neodecanoate, which is 0.1 wt% based on the mass of the first component.

[0069]

[0070] The specific preparation steps are as follows:

[0071] (1) Add polytrimethylene ether glycol (PO3G, number average molecular weight of 2000) into the reaction apparatus, heat to 110°C, and dehydrate under vacuum for 4 hours;

[0072] (2) Cool down to 70°C, add isophorone diisocyanate, then control the temperature at 75°C, stir and react for 3 hours until the reaction reaches the theoretical value of isocyanate.

[0073] (3) Cool down to 60°C, add mono-terminated dihydroxy polydimethylsiloxane (number average molecular weight of 1000), BDO, 2,2-dimethylolpropionic acid, bismuth neodecanoate, acetone, and castor oil, and stir the reaction at 60°C for 3 hours; wherein, based on the raw materials as 100wt%, the amount of acetone used is 30wt%;

[0074] (4) Cool down to 40°C, add sodium 2-[(2-aminoethyl)amino]ethanesulfonate, keep the temperature at 40°C, stir and react for 60 minutes to obtain the prepolymer;

[0075] (5) The prepolymer is transferred into a dispersion device at 40°C. Triethylamine is added to neutralize the prepolymer for 30 minutes. Deionized water is then used to disperse the prepolymer at 1500 rpm for 30 minutes. Ethylenediamine is added to further react for 20 minutes to obtain the dispersion. The amount of deionized water is just enough to disperse the prepolymer into a stable emulsion.

[0076] (6) The dispersion is transferred into a vacuum device and the temperature is controlled at 45°C to remove acetone and obtain a bio-based waterborne polyurethane emulsion.

[0077] Example 2

[0078] Except for replacing “polytrimethylene ether glycol (PO3G, number average molecular weight 2000)” with “polycarbonate glycol (Mofltive HBE, number average molecular weight 2000)”, the other steps are the same as in Example 1.

[0079] Example 3

[0080] Except for replacing "isophorone diisocyanate" with "hexamethylene diisocyanate", the other steps are the same as in Example 1.

[0081] Example 4

[0082] Except for replacing "isophorone diisocyanate" with "diphenylmethane diisocyanate", the other steps are the same as in Example 1.

[0083] Example 5

[0084] Except for replacing “single-terminated dihydroxy polydimethylsiloxane (number average molecular weight of 1000)” with “single-terminated dihydroxy polydimethylsiloxane (number average molecular weight of 3000)”, the other steps are the same as in Example 1.

[0085] Example 6

[0086] Except for replacing “BDO” with “1,6-hexanediol”, the first component is shown in the table below, and the remaining steps are the same as in Example 1.

[0087]

[0088] Example 7

[0089] Except for replacing “2,2-dimethylolpropionic acid” with “2,2-dimethylolbutyric acid” and replacing “polytrimethylene ether glycol (PO3G, number average molecular weight 2000)” with “polycarbonate glycol (Mofltive HBE, number average molecular weight 1000)”, the first component is shown in the table below, and the remaining steps are the same as in Example 1.

[0090]

[0091] Example 8

[0092] A bio-based waterborne polyurethane emulsion, the raw material composition of which includes a first component and a second component, wherein the first component is shown in the table below, the number average molecular weight of polytrimethylene ether glycol is adjusted to 600, and the second component is bismuth isooctanoate, which is 0.5wt% based on the mass of the first component.

[0093]

[0094] The specific preparation steps are as follows:

[0095] (1) Add polytrimethylene ether glycol (PO3G, number average molecular weight of 600) into the reaction apparatus, heat to 115°C, and dehydrate under vacuum for 3 hours;

[0096] (2) Cool down to 50°C, add isophorone diisocyanate, then control the temperature at 70°C, stir and react for 3 hours until the reaction reaches the theoretical value of isocyanate.

[0097] (3) Cool down to 50°C, add mono-terminated dihydroxy polydimethylsiloxane (number average molecular weight of 1000), BDO, 2,2-dimethylolpropionic acid, bismuth isooctanoate, acetone, and castor oil, and stir the reaction at 50°C for 5 hours; wherein, based on the raw materials as 100wt%, the amount of acetone used is 30wt%;

[0098] (4) Cool down to 30°C, add sodium 2-[(2-aminoethyl)amino]ethanesulfonate, keep the temperature at 30°C, stir and react for 30 minutes to obtain the prepolymer;

[0099] (5) The prepolymer is transferred into a dispersion device at 35°C. Triethylamine is added to neutralize the prepolymer for 40 minutes. Deionized water is used to disperse the prepolymer at 1500 rpm for 30 minutes. Ethylenediamine is added to further react for 10 minutes to obtain the dispersion. The amount of deionized water is just enough to disperse the prepolymer into a stable emulsion.

[0100] (6) The dispersion is transferred into a vacuum device and the temperature is controlled at 25°C to remove acetone and obtain a bio-based waterborne polyurethane emulsion.

[0101] Example 9

[0102] A bio-based waterborne polyurethane emulsion comprises a first component and a second component. The first component, as shown in the table below, mainly replaces "castor oil" with "trimethylolpropane" and replaces "polytrimethylene ether glycol (PO3G) with a number average molecular weight of 2000" with "polytrimethylene ether glycol (PO3G) with a number average molecular weight of 3000". The second component is bismuth isooctanoate, which is 0.1 wt% based on the mass of the first component.

[0103] The first component is shown in the table below, and the remaining steps are the same as in Example 1.

[0104]

[0105] Example 10

[0106] Replace “ethylenediamine” with “dicyclohexylmethanediamine”. The first component is shown in the table below.

[0107]

[0108] The specific preparation steps are as follows:

[0109] (1) Add polytrimethylene ether glycol (PO3G, number average molecular weight of 2000) into the reaction apparatus, heat to 110°C, and dehydrate under vacuum for 4 hours;

[0110] (2) Cool down to 70°C, add isophorone diisocyanate, then control the temperature at 80°C, stir and react for 2 hours until the reaction reaches the theoretical value of isocyanate.

[0111] (3) Cool down to 60°C, add mono-terminated dihydroxy polydimethylsiloxane (number average molecular weight of 1000), BDO, 2,2-dimethylolpropionic acid, bismuth neodecanoate, acetone, and castor oil, and stir the reaction at 60°C for 3 hours; wherein, based on the raw materials as 100wt%, the amount of acetone used is 30wt%;

[0112] (4) Cool down to 40°C, add sodium 2-[(2-aminoethyl)amino]ethanesulfonate, keep the temperature at 40°C, stir and react for 60 minutes to obtain the prepolymer;

[0113] (5) The prepolymer is transferred into a dispersion device at 40°C. Triethylamine is added for neutralization for 30 minutes, and deionized water is used for high-speed dispersion at 1500 rpm for 30 minutes. Dicyclohexylmethanediamine is added for further reaction for 60 minutes to obtain the dispersion. The amount of deionized water is just enough to disperse the prepolymer into a stable emulsion.

[0114] (6) The dispersion is transferred into a vacuum device and the temperature is controlled at 75°C to remove acetone and obtain a bio-based waterborne polyurethane emulsion.

[0115] Example 11

[0116] Except for replacing "triethylamine" with "triethanolamine", the first component is shown in the table below, and the remaining steps are the same as in Example 1.

[0117]

[0118] Example 12

[0119] Except for replacing “50wt% polytrimethylene ether glycol (PO3G, number average molecular weight of 2000)” with “40wt% polytrimethylene ether glycol (PO3G, number average molecular weight of 2000)” and “30wt% isophorone diisocyanate” with “40wt% isophorone diisocyanate”, the other steps are the same as in Example 1.

[0120] Example 13

[0121] Except for replacing “2wt% single-ended dihydroxy polydimethylsiloxane, number average molecular weight of 1000” with “5wt% single-ended dihydroxy polydimethylsiloxane, number average molecular weight of 3000”, replacing “4wt% BDO” with “2wt% BDO”, and replacing “4wt% ethylenediamine” with “3wt% ethylenediamine”, the remaining steps are the same as in Example 1.

[0122] Example 14

[0123] A bio-based aqueous polyurethane emulsion comprises a first component and a second component, wherein the first component is shown in the table below, and the second component is bismuth neodecanoate, which is 0.1 wt% based on the mass of the first component.

[0124]

[0125] Steps (1) to (2) are the same as in Example 1;

[0126] (3) Cool down to 60°C, add BDO, 2,2-dimethylolpropionic acid, bismuth neodecanoate, acetone, and castor oil, and stir the reaction for 3 hours while maintaining the temperature at 60°C; wherein, based on the raw materials as 100wt%, the amount of acetone used is 30wt%;

[0127] (4) Cool down to 40°C, add sodium 2-[(2-aminoethyl)amino]ethanesulfonate, keep the temperature at 40°C, stir and react for 60 minutes to obtain the prepolymer;

[0128] (5) The prepolymer was transferred into a dispersion device at 40°C. Triethylamine was added to neutralize it for 30 minutes. Deionized water was then used to disperse it at 1500 rpm for 30 minutes. Ethylenediamine was added to further react for 20 minutes to obtain the dispersion.

[0129] (6) The dispersion was mixed with a siloxane chain extender (single-terminated dihydroxy polydimethylsiloxane with a number average molecular weight of 1000) and then transferred into a vacuum device. The temperature was controlled at 45°C to remove acetone and obtain a bio-based waterborne polyurethane emulsion.

[0130] Comparative Example 1

[0131] Except for replacing “single-terminated dihydroxy polydimethylsiloxane with a number average molecular weight of 1000” with “α-hydrogen-ω-hydroxy-polydimethylsiloxane with a number average molecular weight of 1000”, the other steps are the same as in Example 1.

[0132] Comparative Example 2

[0133] Except for replacing “polytrimethylene ether glycol (PO3G, number average molecular weight 2000)” with “general polyol (Mackin PBA-2000)”, the other steps are the same as in Example 1.

[0134] Comparative Example 3

[0135] A bio-based aqueous polyurethane emulsion comprises a first component and a second component, wherein the first component is shown in the table below, and the second component is bismuth neodecanoate, which is 0.1 wt% based on the mass of the first component.

[0136]

[0137] The remaining steps are the same as in Example 1.

[0138] Comparative Example 4

[0139] A bio-based aqueous polyurethane emulsion comprises a first component and a second component, wherein the first component is shown in the table below, and the second component is bismuth neodecanoate, which is 0.1 wt% based on the mass of the first component.

[0140]

[0141] The remaining steps are the same as in Example 1.

[0142] Comparative Example 5

[0143] A bio-based aqueous polyurethane emulsion comprises a first component and a second component, wherein the first component is shown in the table below, and the second component is bismuth neodecanoate, which is 0.1 wt% based on the mass of the first component.

[0144]

[0145] The remaining steps are the same as in Example 1.

[0146] Comparative Example 6

[0147] A bio-based aqueous polyurethane emulsion comprises a first component and a second component, wherein the first component is shown in the table below, and the second component is bismuth neodecanoate, which is 0.1 wt% based on the mass of the first component.

[0148]

[0149] The remaining steps are the same as in Example 1.

[0150] Comparative Example 7

[0151] A bio-based aqueous polyurethane emulsion comprises a first component and a second component, wherein the first component is shown in the table below, and the second component is bismuth neodecanoate, which is 0.1 wt% based on the mass of the first component.

[0152]

[0153] The specific preparation steps are as follows:

[0154] (1) Add polytrimethylene ether glycol (PO3G, number average molecular weight of 2000) into the reaction apparatus, heat to 110°C, and dehydrate under vacuum for 4 hours;

[0155] (2) Cool down to 70°C, add isophorone diisocyanate, then control the temperature at 75°C, stir and react for 3 hours until the reaction reaches the theoretical value of isocyanate.

[0156] (3) Cool down to 60°C, add BDO, 2,2-dimethylolpropionic acid, bismuth neodecanoate, acetone, and castor oil, and stir the reaction for 3 hours while maintaining the temperature at 60°C; wherein, based on the raw materials as 100wt%, the amount of acetone used is 30wt%;

[0157] (4) Cool down to 40°C, add sodium 2-[(2-aminoethyl)amino]ethanesulfonate, keep the temperature at 40°C, stir and react for 60 minutes to obtain the prepolymer;

[0158] (5) The prepolymer is transferred into a dispersion device at 40°C. Triethylamine is added to neutralize the prepolymer for 30 minutes. Deionized water is then used to disperse the prepolymer at 1500 rpm for 30 minutes. Ethylenediamine is added to further react for 20 minutes to obtain the dispersion. The amount of deionized water is just enough to disperse the prepolymer into a stable emulsion.

[0159] (6) The dispersion is transferred into a vacuum device and the temperature is controlled at 45°C to remove acetone and obtain a bio-based waterborne polyurethane emulsion.

[0160] The performance parameters of each embodiment and comparative example are shown in Table 1.

[0161] Table 1

[0162]

[0163] As can be seen from Table 1, the raw material selection, component content, and preparation method parameters of the bio-based waterborne polyurethane emulsions in Examples 1 to 14 are within the scope of this application. The water absorption rate of the films in each example is significantly reduced, while possessing high bio-based content and high solid content, as well as good water resistance, slipperiness, and durability, which are generally superior to Comparative Examples 1-7. Specifically, compared with Example 1, Comparative Example 1, due to the absence of the single-terminated dihydroxy polydimethylsiloxane of this application, has a higher water absorption rate, a significantly worse slipperiness, and a certain decline in rubbing fastness. This indicates that the addition of a specific siloxane chain extender has a good supporting effect on achieving good surface effects. Compared with Example 1, Comparative Example 2 shows a significant decrease in bulk properties such as water resistance and rubbing fastness, and a certain decline in slipperiness. This indicates that the addition of a specific bio-based polyol has a good supporting effect on achieving bulk durability. Compared with Example 1, Comparative Examples 1 and 2 show that the membrane in Example 1 has a significantly lower water absorption rate, combining high bio-based content with high solids content, while simultaneously imparting excellent water resistance, outstanding slipperiness, and durable durability to the coating, achieving a comprehensive and excellent balance of performance. Comparative Examples 3 to 6, compared with Example 1, show that the content of the raw material components (bio-based polyols, isocyanates, and siloxane chain extenders) in the bio-based waterborne polyurethane emulsions is outside the scope of this application. The resulting bio-based waterborne polyurethane emulsions exhibit varying degrees of decreased slipperiness or durability, failing to simultaneously possess high bio-based content and high solids content while also exhibiting high water resistance, slipperiness, and durability. Compared with Example 1, Comparative Example 7 did not add single-ended dihydroxy polydimethylsiloxane. Its smoothness, rubbing fastness and water resistance were reduced to varying degrees. This shows that single-ended dihydroxy polydimethylsiloxane is not an ordinary auxiliary agent that can be omitted. Rather, it is a key structural component that gives the coating excellent surface properties (high smoothness, low friction and strong hydrophobicity). Its absence makes it impossible to meet the comprehensive requirements of high-end printed products for smoothness, durability and water resistance.

[0164] In summary, the selection of raw materials and component content of the bio-based waterborne polyurethane emulsion in this application are within the scope of this application. The resulting bio-based waterborne polyurethane emulsion has high bio-based content and high solid content, as well as high water resistance, smoothness and durability.

[0165] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A bio-based aqueous polyurethane emulsion comprising raw materials and deionized water; wherein, The raw material comprises a first component and a second component; the first component comprises a bio-based polyol, an isocyanate, a siloxane chain extender, a small molecule chain extender, a hydrophilic chain extender, a crosslinking agent, a polyamine chain extender and a neutralizing agent; based on the mass of the first component, the bio-based polyol is 40wt%-50wt%, the isocyanate is 30wt%-40wt%, the siloxane chain extender is 2wt%-5wt%, the small molecule chain extender is 2wt%-6wt%, the hydrophilic chain extender is 4wt%-6wt%, the crosslinking agent is 0.5wt%-2wt%, the polyamine chain extender is 2wt%-6wt%, and the neutralizing agent is 3wt%-5wt%; the second component comprises a catalyst, and the catalyst is 0.1wt%-0.5wt% based on the mass of the first component; the siloxane chain extender is selected from a mono-end dihydroxy polydimethylsiloxane; the hydrophilic chain extender comprises a dicarboxylic acid hydrophilic monomer and a disulfonic acid hydrophilic monomer; and the bio-based waterborne polyurethane emulsion has a solid content of 45wt%-53wt%.

2. The bio-based aqueous polyurethane emulsion according to claim 1, wherein, The bio-based polyol is selected from at least one of a polytrimethylene ether glycol and a polycarbonate glycol; preferably, the polytrimethylene ether glycol has a number average molecular weight of 600-3000, and the polycarbonate glycol has a number average molecular weight of 1000-2000.

3. The bio-based aqueous polyurethane emulsion of claim 1, wherein, The isocyanate is selected from a diisocyanate; preferably, the isocyanate is selected from at least one of isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate and toluene diisocyanate.

4. The bio-based aqueous polyurethane emulsion of claim 1, wherein, The mono-end dihydroxy polydimethylsiloxane has a number average molecular weight of 1000-3000.

5. The bio-based aqueous polyurethane emulsion of claim 1, wherein, The small molecule chain extender is selected from at least one of 1,4-butanediol, 1,6-hexanediol, propylene glycol and pentanediol.

6. The bio-based aqueous polyurethane emulsion of claim 1, wherein, The dicarboxylic acid hydrophilic monomer is selected from at least one of 2,2-dimethylol propionic acid, 2,2-dimethylol butyric acid and 3,5-dihydroxy-3-methyl valeric acid; and the disulfonic acid hydrophilic monomer is selected from 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt.

7. The bio-based aqueous polyurethane emulsion of claim 1, wherein, The catalyst is selected from at least one of bismuth neodecanoate and bismuth iso-octoate.

8. The bio-based aqueous polyurethane emulsion of claim 1, wherein, The crosslinking agent is selected from at least one of castor oil and trimethylolpropane.

9. The bio-based aqueous polyurethane emulsion of claim 1, wherein, The polyamine chain extender is selected from at least one of an organic primary amine containing two active hydrogens, an inorganic primary amine containing two active hydrogens, an organic secondary amine containing two active hydrogens and an inorganic secondary amine containing two active hydrogens; preferably, the polyamine chain extender is selected from at least one of ethylenediamine, isophorone diamine, hexamethylenediamine, diethylenetriamine, phenylenediamine, toluenediamine and dicyclohexylmethane diamine.

10. The bio-based aqueous polyurethane emulsion of claim 1, wherein, The neutralizing agent is selected from at least one of triethylamine, ammonia and triethanolamine.

11. A preparation method of the bio-based waterborne polyurethane emulsion according to any one of claims 1-10, comprising: (1) putting a bio-based polyol into a reaction device, heating to 110-115°C, and vacuum dehydrating for 3-4 hours; (2) cooling to 50-70°C, adding an isocyanate, heating to 70-80°C and reacting for 2-3 hours; (3) cooling to 50~60℃, adding silicone chain extender, small molecule chain extender, catalyst, organic solvent, crosslinking agent, dicarboxylic acid hydrophilic monomer, temperature control at 50~60℃ for 3~5 hours; (4) cooling to 30~40℃, adding dicarboxylic acid hydrophilic monomer, temperature control at 30~40℃ for 30~60 minutes, to obtain a prepolymer; (5) moving the prepolymer into a dispersion device, temperature at 35~40℃, adding neutralizing agent for 30~40 minutes, high-speed dispersion with deionized water, adding polyamine chain extender for further reaction for 10~60 minutes, to obtain a dispersion; (6) moving the dispersion into a reduced pressure device, temperature control at 25~75℃, removing organic solvent, to obtain the bio-based waterborne polyurethane emulsion.

12. Application of the bio-based waterborne polyurethane emulsion according to any one of claims 1~10 or prepared by the preparation method of claim 11 in printing glue.

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