Bio-based PDI aqueous polyurethane emulsion, its preparation method and application

Abstract

The present invention discloses a bio-based PDI aqueous polyurethane emulsion, which is prepared from a system formed by the following components in parts by weight: 70 to 90 parts of a first bio-based polyol, 30 to 50 parts of a second bio-based polyol, 25 to 45 parts of 1,5-pentane diisocyanate, 0.5 to 2.5 parts of a catalyst, and 4 to 6 parts of a neutralizing agent; wherein, the first bio-based polyol and the second bio-based polyol are each independently selected from any one of polypropylene glycol, polycarbonate diol or polylactic acid polyol. The present invention prepares a bio-based PDI aqueous polyurethane emulsion from the first bio-based polyol, the second bio-based polyol and 1,5-pentane diisocyanate, which expands the proportion of bio-based components, is green and environmentally friendly, and the emulsion has good stability and has good thermal stability and tensile strength after curing into a film. The bio-based PDI aqueous polyurethane emulsion provided by the present invention can be applied to printing coatings, and the fabric treated with the printing coating has bright colors and a soft handfeel.

Description

Technical Field

[0001] The present invention relates to waterborne polyurethane materials, and particularly to a bio-based PDI waterborne polyurethane emulsion, a preparation method thereof, and an application thereof. Background Art

[0002] With the depletion of petroleum resources and the popularization of the concept of green ecological development, in order to reduce the dependence on traditional petrochemical resources and reduce carbon emissions, bio-based products have gradually replaced traditional petroleum resources, and the proportion of waterborne polyurethane in the coating printing industry has been increasing year by year.

[0003] 1,5-Pentane diisocyanate (PDI) is prepared from biomass such as corn straw, and its additives such as rice bran wax also come from renewable resources such as corn and castor, and it is a green material. PDI has excellent properties such as high strength, high toughness, oil resistance, and yellowing resistance, and is environmentally friendly and low-toxic. However, the waterborne polyurethane emulsion prepared from PDI as the hard segment in the prior art has weak stability, and the tensile strength after curing into a film is low, so it is difficult to be used as a coating in coating printing. Summary of the Invention

[0004] The first object of the present invention is to provide a bio-based PDI waterborne polyurethane emulsion to solve at least one of the above technical problems.

[0005] The second object of the present invention is to provide a preparation method of a bio-based PDI waterborne polyurethane emulsion to solve at least one of the above technical problems.

[0006] The third object of the present invention is to provide a bio-based PDI printing coating to solve at least one of the above technical problems.

[0007] According to the first aspect of the present invention, there is provided a bio-based PDI waterborne polyurethane emulsion, which is prepared from a system composed of the following components in parts by weight: 70-90 parts of a first bio-based polyol, 30-50 parts of a second bio-based polyol, 25-45 parts of 1,5-pentane diisocyanate, 0.5-2.5 parts of a catalyst, and 4-6 parts of a neutralizing agent;

[0008] Wherein, the first bio-based polyol and the second bio-based polyol are each independently selected from any one of polypropylene glycol, polycarbonate diol, or polylactic acid polyol.

[0009] The bio-based PDI waterborne polyurethane emulsion according to the present invention has good emulsion stability. A bio-based PDI waterborne polyurethane emulsion with a high bio-based content is prepared by using 1,5-pentane diisocyanate and a variety of bio-based polyols, and has good thermal stability and tensile strength after curing into a film.

[0010] In some embodiments, the number-average molecular weight of polypropylene glycol may be 600 to 3000, the number-average molecular weight of polycarbonate diol may be 500 to 3000, and the number-average molecular weight of polylactic acid polyol may be 1000 to 2000. By adjusting the combination, number-average molecular weight and content of the bio-based polyol, a bio-based PDI aqueous polyurethane emulsion that meets the mechanical properties after curing and film formation can be obtained.

[0011] In some embodiments, the neutralizing agent may be any one of triethylamine, dimethylaminoethanol or triethanolamine.

[0012] In some embodiments, the molar ratio of the neutralizing agent to the carboxyl group in the reaction system is (0.9 to 1.1):1.

[0013] In some embodiments, the catalyst may be at least one of organic bismuth or bismuth neodecanoate. Specifically, the catalyst can be bismuth neodecanoate DY-20, and its bismuth content is 20% ± 0.5.

[0014] In some embodiments, based on parts by weight, the system further includes 2 to 10 parts of a hydrophilic chain extender.

[0015] In some embodiments, the hydrophilic chain extender may be at least one of 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, or glycerol tartrate.

[0016] In some embodiments, based on parts by weight, the system further includes 6 to 11 parts of a small molecule chain extender.

[0017] In some embodiments, the small molecule chain extender may be any one or two of PEG, diethylenetriamine, ethylenediamine, or isophorone diamine. Specifically, the number-average molecular weight of PEG may be 200 to 600. PEG acts as both a small molecule chain extender and a compatibilizer in the system, and is used to improve the problem of uneven compatibility reaction between polycarbonate diol as the soft segment and PDI and the hydrophilic chain extender.

[0018] According to the second aspect of the present invention, a method for preparing a bio-based PDI aqueous polyurethane emulsion is provided.

[0019] In some embodiments, the method for preparing a bio-based PDI aqueous polyurethane emulsion includes the following steps:

[0020] S1. Add the first biobased polyol and the second biobased polyol into a reactor, and conduct a reduced-pressure dehydration reaction in a nitrogen atmosphere. Then cool down the temperature to 60°C - 70°C, add 1,5-pentanediisocyanate and a catalyst into the reactor, and carry out an isothermal reaction at 80°C - 85°C for 1.5 - 3 h. Then add an organic solvent, and cool down the temperature to 45 - 55°C to obtain a biobased PDI polyurethane prepolymer;

[0021] S2. Add a neutralizing agent to the biobased PDI polyurethane prepolymer and neutralize for 8 - 12 min, add deionized water for an emulsification reaction, and remove the organic solvent under vacuum at 40 - 50°C, thus obtaining the product.

[0022] In some other embodiments, the preparation method of the biobased PDI aqueous polyurethane emulsion comprises the following steps:

[0023] S1. Add the first biobased polyol and the second biobased polyol into a reactor, and conduct a reduced-pressure dehydration reaction in a nitrogen atmosphere. Then cool down the temperature to 60°C - 70°C, add 1,5-pentanediisocyanate into the reactor, and carry out an isothermal reaction at 80°C - 85°C for 1.5 - 3 h. Cool down the temperature to 55°C - 65°C, then add a catalyst and a chain extender into the reactor, and carry out an isothermal reaction at 60°C - 80°C for 3 - 5 h. Then add an organic solvent, and cool down the temperature to 45 - 55°C to obtain a biobased PDI polyurethane prepolymer;

[0024] S2. Add a neutralizing agent to the biobased PDI polyurethane prepolymer and neutralize for 8 - 12 min, add deionized water for an emulsification reaction, and remove the organic solvent under vacuum at 40 - 50°C, thus obtaining the product;

[0025] Among them, the chain extender is at least one of a hydrophilic chain extender and a small molecule chain extender.

[0026] In some embodiments, the organic solvent can be any one of acetone or butanone.

[0027] In some embodiments, in step S1, the treatment method of reduced-pressure dehydration is to conduct reduced-pressure dehydration for 1 - 2 h under the conditions of a temperature of 100 - 120°C and a vacuum degree greater than 0.085 MPa.

[0028] In some embodiments, the treatment method of the emulsification reaction in step S2 is to first disperse at a rotation speed of 1800 - 2200 r / min for 4 - 6 min, and then disperse at a rotation speed of 900 - 1100 r / min for 0.8 - 1.2 h.

[0029] In some other embodiments, the treatment method of the emulsification reaction in step S2 is as follows: after adding a neutralizing agent to the bio-based PDI polyurethane prepolymer for neutralization, a small molecule chain extender is first added, then deionized water is added, and the mixture is dispersed at a rotation speed of 1800 - 2200 r / min for 4 - 6 min, and then dispersed at a rotation speed of 900 - 1100 r / min for 0.8 - 1.2 h.

[0030] In some other embodiments, the treatment method of the emulsification reaction in step S2 is as follows: after adding a neutralizing agent to the bio-based PDI polyurethane prepolymer for neutralization, a small molecule chain extender is first added, then deionized water is added, and the mixture is dispersed at a rotation speed of 1800 - 2200 r / min for 4 - 6 min, and then dispersed at a rotation speed of 900 - 1100 r / min for 0.8 - 1.2 h.

[0031] According to the third aspect of the present invention, there is provided an application of the bio-based PDI aqueous polyurethane emulsion in printing coatings.

[0032] The bio-based PDI aqueous polyurethane emulsion according to the present invention can be formulated into a printing coating, and the printing coating can be applied to the surface of the fabric by mechanical or manual methods. The fabric treated with the printing coating has bright colors, no obvious fading after heat treatment, and a soft hand feeling.

[0033] In some embodiments, by weight, the printing coating comprises the following components: 80 - 90 parts of the bio-based PDI aqueous polyurethane emulsion, 0.5 - 1.5 parts of an antifoaming agent, 2 - 4 parts of a thickening agent, and 8 - 12 parts of a color paste.

[0034] The beneficial effects of the present invention include:

[0035] (1) The bio-based PDI aqueous polyurethane emulsion of the present invention is prepared from a first bio-based polyol, a second bio-based polyol, and 1,5-pentane diisocyanate, reducing the use of non-renewable petroleum resources and being a green and environmentally friendly material; moreover, the prepared bio-based PDI aqueous polyurethane emulsion has good stability, and after curing into a film, it has good tensile strength and thermal stability;

[0036] (2) The bio-based PDI aqueous polyurethane emulsion of the present invention can be applied to printing coatings, and the fabric treated with the printing coating has bright colors and a soft hand feeling. Description of the Drawings

[0037] Figure 1 It is an infrared spectrum diagram of the bio-based PDI aqueous polyurethane emulsion prepared by the preparation methods of Examples 1 - 4 of the present invention;

[0038] Figure 2 It is a particle size curve diagram of the bio-based PDI aqueous polyurethane emulsion prepared by the preparation methods of Examples 1 - 4 of the present invention.

[0039] Figure 3 The stress-strain curves of the WPU cured films formed by curing the bio-based PDI aqueous polyurethane emulsions prepared by the preparation methods of Examples 1 to 4 of the present invention;

[0040] Figure 4 The TGA curves of the WPU cured films formed by curing the bio-based PDI aqueous polyurethane emulsions prepared by the preparation methods of Examples 1 to 4 of the present invention;

[0041] Figure 5 The DTG curves of the WPU cured films formed by curing the bio-based PDI aqueous polyurethane emulsions prepared by the preparation methods of Examples 1 to 4 of the present invention;

[0042] Figure 6 (A) The physical picture of the printing coating of Example 5 of the present invention coated on cotton cloth; Figure 6 (B) The physical picture of the printing coating of Example 6 of the present invention coated on cotton cloth; Figure 6 (C) The physical picture of the printing coating of Example 7 of the present invention coated on cotton cloth; Figure 6 (D) The physical picture of the printing coating of Example 8 of the present invention coated on cotton cloth;

[0043] Figure 7 (A) The physical picture of the printing coating of Example 5 of the present invention coated on swimsuit fabric; Figure 7 (B) The physical picture of the printing coating of Example 6 of the present invention coated on a swimsuit; Figure 7 (C) The physical picture of the printing coating of Example 7 of the present invention coated on a swimsuit; Figure 7 (D) The physical picture of the printing coating of Example 8 of the present invention coated on swimsuit fabric. Detailed implementation manners

[0044] The present invention will be further described in detail below with reference to the accompanying drawings, but the implementation manners of the present invention are not limited thereto. The raw materials and reagents involved in the following examples can be obtained from commercial channels.

[0045] Example 1

[0046] This example provides a preparation method of a bio-based PDI aqueous polyurethane emulsion, including the following steps:

[0047] In a nitrogen atmosphere, 80 parts of bio-based PPG (number-average molecular weight of 2000) and 40 parts of bio-based PCD (number-average molecular weight of 1000) were added to a reaction kettle. Under the conditions of a temperature of 115 °C and a vacuum degree greater than 0.085 MPa, dehydration reaction was carried out under reduced pressure for 2 h. After cooling to 65 °C, 30 parts of PDI were added to the reaction kettle. After reacting at a constant temperature of 85 °C for 2 h, the temperature was cooled to 60 °C. Then, 8 parts of DMPA, 4 parts of PEG (number-average molecular weight of 400), and 2 parts of bismuth neodecanoate were added. The temperature was raised to 75 °C and reacted at a constant temperature for 5 h. Acetone was added to adjust the viscosity of the system. After cooling to 50 °C, triethylamine equimolar to the carboxyl group in the reaction system was added to the reaction kettle for a neutralization reaction for 10 min. Then, 200 g of deionized water was added. After dispersing at a speed of 2000 r / min in a high-speed disperser for 5 min, 2.8 parts of diethylenediamine were added. Then, it was dispersed at a speed of 1000 r / min in a high-speed disperser for 1 h. After completing the emulsification reaction, acetone was removed in a vacuum environment at 45 °C to obtain the product.

[0048] The product obtained in Example 1 was subjected to infrared detection, and the infrared spectrum was as Figure 1 shown. From Figure 1 it can be seen that the characteristic absorption peak at 2270 cm -1 disappeared (-N=C=O), indicating that the hydroxyl groups of PPG and PCD reacted completely with the isocyanate groups in PDI. At 2971.761 cm -1 were the stretching vibration peaks of -CH2 and -CH3. At 1725.978 cm -1 was the stretching vibration peak of C=O. The stretching vibration peaks of -COO appeared at 1255 cm -1 and 1166 cm -1 , indicating the successful synthesis of the bio-based PDI aqueous polyurethane emulsion.

[0049] Example 2

[0050] This example provides a preparation method of a bio-based PDI aqueous polyurethane emulsion, including the following steps:

[0051] In a nitrogen atmosphere, 80 parts of bio-based PPG (number-average molecular weight of 2000) and 40 parts of bio-based PCD (number-average molecular weight of 1000) were added to a reaction kettle. Under the conditions of a temperature of 115 °C and a vacuum degree greater than 0.085 MPa, the reaction was carried out under reduced pressure to dehydrate for 2 h. Then the temperature was lowered to 65 °C, and 30 parts of PDI were added to the reaction kettle. After reacting at a constant temperature of 85 °C for 2 h, the temperature was lowered to 60 °C. Then 9 parts of glycerol tartrate, 8 parts of PEG (number-average molecular weight of 400), and 0.5 part of bismuth neodecanoate were added. The temperature was raised to 70 °C and the reaction was carried out at a constant temperature for 3 h. Acetone was added to adjust the viscosity of the system. The temperature was lowered to 50 °C. Then, triethylamine equimolar to the carboxyl groups in the reaction system was added to the reaction kettle for a neutralization reaction for 10 min. Then 200 g of deionized water was added, and it was dispersed in a high-speed disperser at a speed of 2000 r / min for 5 min and then dispersed in the high-speed disperser at a speed of 1000 r / min for 1 h. After the emulsification reaction was completed, acetone was removed in a vacuum environment at 45 °C to obtain the product.

[0052] The product obtained in Example 2 was subjected to infrared detection, and the infrared spectrum was as Figure 1 shown. From Figure 1 it can be seen that the positions of its characteristic peaks are basically the same as those in Example 1, which also indicates that the bio-based PDI aqueous polyurethane emulsion in Example 2 was successfully synthesized.

[0053] Example 3

[0054] This example provides a preparation method of a bio-based PDI aqueous polyurethane emulsion, including the following steps:

[0055] In a nitrogen atmosphere, 80 parts of bio-based PPG (number-average molecular weight of 2000) and 40 parts of polylactic acid polyol (number-average molecular weight of 1000) were added to a reaction kettle. Under the conditions of a temperature of 115 °C and a vacuum degree greater than 0.085 MPa, the reaction was carried out under reduced pressure to dehydrate for 2 h. Then the temperature was lowered to 65 °C, and 40 parts of PDI and 0.5 part of bismuth neodecanoate were added to the reaction kettle. The temperature was raised to 85 °C and the reaction was carried out at a constant temperature for 2 h. 8 parts of DMPA and 30 parts of acetone were added to adjust the viscosity of the system. The temperature was lowered to 50 °C. Then, triethylamine equimolar to the carboxyl groups in the reaction system was added to the reaction kettle for a neutralization reaction for 10 min. Then 250 g of deionized water and 4.5 parts of ethylenediamine were added, and it was dispersed in a high-speed disperser at a speed of 2000 r / min for 5 min and then dispersed in the high-speed disperser at a speed of 1000 r / min for 1 h. After the emulsification reaction was completed, acetone was removed in a vacuum environment at 45 °C to obtain the product.

[0056] The product obtained in Example 3 was subjected to infrared detection, and the infrared spectrum was as Figure 1 shown. From Figure 1It can be seen that the positions of the characteristic peaks are basically the same as those in Example 1, indicating that the hydroxyl groups of PPG and polylactic acid polyol react completely with the isocyanate groups in PDI, and also indicating the successful synthesis of the bio-based PDI aqueous polyurethane emulsion in Example 3.

[0057] Example 4

[0058] This example provides a preparation method of a bio-based PDI aqueous polyurethane emulsion, which includes the following steps:

[0059] In a nitrogen atmosphere, 80 parts of polylactic acid polyol (number average molecular weight of 2000) and 40 parts of bio-based PCD (number average molecular weight of 1000) are added to a reaction kettle, and under the conditions of a temperature of 115 °C and a vacuum degree greater than 0.085 MPa, the pressure is reduced for dehydration reaction for 2 h. After cooling to 65 °C, 40 parts of PDI are added to the reaction kettle. After reacting at a constant temperature of 85 °C for 2 h, the temperature is cooled to 60 °C, then 6.8 parts of methyl propanediol and 2 parts of bismuth neodecanoate are added, and the temperature is raised to 75 °C for a constant temperature reaction for 2 h. Acetone is added to adjust the viscosity of the system. After cooling to 50 °C, then triethylamine equimolar to the carboxyl groups in the reaction system is added to the reaction kettle for a neutralization reaction for 10 min, and then 250 g of deionized water is added. After high-speed dispersion at a speed of 2000 r / min for 5 min, followed by low-speed dispersion at a speed of 1000 r / min for 1 h, acetone is removed in a vacuum environment at 45 °C after the emulsification reaction is completed to obtain the product.

[0060] The product obtained in Example 4 is subjected to infrared detection, and the infrared spectrum is as Figure 1 shown. From Figure 1 It can be seen that the positions of the characteristic peaks are basically the same as those in Example 1, indicating that the hydroxyl groups of polylactic acid polyol and PCD react completely with the isocyanate groups in PDI, and also indicating the successful synthesis of the bio-based PDI aqueous polyurethane emulsion in Example 4.

[0061] Example 5

[0062] This example provides a printing coating, and the preparation method is as follows: By weight, 90 parts of the bio-based PDI aqueous polyurethane emulsion prepared in Example 1, 1 part of defoamer 580, 3 parts of thickener N-0010, 0.8 part of pH regulator AMP95, and 10 parts of scarlet paste are mixed to obtain it.

[0063] Example 6

[0064] This example provides a printing coating, and the preparation method is as follows: By weight, 90 parts of the bio-based PDI aqueous polyurethane emulsion prepared in Example 2, 1 part of defoamer 580, 3 parts of thickener N-0010, and 10 parts of scarlet paste are mixed to obtain it.

[0065] Example 7

[0066] This example provides a printing coating, and the preparation method is as follows: By weight, mix 90 parts of the bio-based PDI aqueous polyurethane emulsion prepared in Example 3, 1 part of defoamer 580, 3 parts of thickener N-0010, and 10 parts of scarlet paste to obtain it.

[0067] Example 8

[0068] This example provides a printing coating, and the preparation method is as follows: By weight, add 90 parts of the bio-based PDI aqueous polyurethane emulsion prepared in Example 4, 1 part of defoamer 580, 1.4 parts of thickener N-0010, 3 parts of propylene glycol, 0.8 part of pH regulator AMP95, 10 parts of scarlet paste, and 1 part of crosslinking agent carbodiimide, and mix to obtain it.

[0069] Experimental Example 1

[0070] In this experimental example, the particle size distribution and zeta potential of the bio-based PDI aqueous polyurethane emulsions prepared in Examples 1 to 4 were detected. The particle size distribution results are as Figure 2 shown in Table 1, and the zeta potential values are shown in Table 1. It can be seen from Figure 2 Table 1 that the average particle sizes and particle size distributions of the bio-based PDI aqueous polyurethane emulsions prepared in Examples 1 to 4 are relatively close, and the average particle size is about 200 nm. The particle sizes of the bio-based PDI aqueous polyurethane emulsions in Examples 1 and 4 are slightly larger than those in Examples 2 and 3. It can be seen from Table 1 that the absolute values of the zeta potential of the bio-based PDI aqueous polyurethane emulsions prepared in Examples 1 to 4 are all greater than 50, indicating that the bio-based PDI aqueous polyurethane emulsions prepared by the preparation method of the present invention all have good storage stability. The maximum absolute value of the zeta potential in Examples 1 and 2 is greater than that in Examples 3 and 4 because PEG was used as a small molecule chain extender in combination with a hydrophilic chain extender in Examples 1 and 2, making it easy for the bio-based prepolymer to be emulsified and improving the problem of easy demulsification during the reaction with the hydrophilic chain extender in the acetone method due to the hydrophobicity of PCD. The zeta potential of Example 2 is greater than that of Example 1 because the melting point of the hydrophilic chain extender in Example 2 is lower, and its diffusion rate in the reaction system is faster, promoting the chain extension reaction.

[0071] Table 1 Zeta potential of bio-based PDI aqueous polyurethane emulsion

[0072] Sample Zeta Potential (mV) Example 1 59.3±4.24 Example 2 69.4±2.31 Example 3 50.7±2.43 Example 4 50.2±1.32

[0073] Experimental Example 2

[0074] Weigh 10 g of the bio-based PDI aqueous polyurethane emulsions prepared in Examples 1 to 4 respectively, place them in a petri dish, dry the petri dish at room temperature for 24 h, and then place the petri dish in an electrothermal constant temperature forced air drying oven at 60 °C for 12 h to obtain a cured film.

[0075] In this experimental example, the cured films obtained by curing the bio-based PDI aqueous polyurethane emulsions prepared in Examples 1 to 4 were subjected to a tensile property test, and the results are as Figure 3 shown. From Figure 3 it can be seen that when the relative deformation of the cured film is the same, the stress of the cured films of Examples 3 and 4 is significantly greater than that of Examples 1 and 2. This is because in Examples 3 and 4, polylactic acid polyol was used to jointly prepare the bio-based PDI aqueous polyurethane with other raw materials, indicating that the bio-based PDI aqueous polyurethane emulsion prepared using bio-based PPG and bio-based PCD as soft segments has more excellent tensile strength after curing into a film. By controlling the combination and relative content of bio-based polyols, a bio-based PDI aqueous polyurethane cured film with the required tensile properties can be formulated.

[0076] Experimental Example 3

[0077] In this experimental example, the cured films obtained by curing the bio-based PDI aqueous polyurethane emulsions prepared in Examples 1 to 4 were subjected to thermal stability analysis, and the results are as Figure 4 and Figure 5 shown, and the 5% weight loss thermal degradation temperature (T 5％ ), 50% weight loss thermal degradation temperature (T 50％ ), maximum degradation rate temperature (T max ), and char residue rate at 700 °C of the cured films of different examples are listed in Table 2.

[0078] From Figure 4 and Figure 5 it can be seen that the thermal degradation of the cured film is roughly divided into two stages. The first stage is the degradation of the hard segment, with a temperature of about 300 °C, and the second stage is the degradation of the soft segment, with a temperature of about 400 °C, indicating that the cured films of Examples 1 to 4 have good thermal stability. It can be seen from Table 2 that the 50% weight loss thermal degradation temperature of the cured films of Examples 1 and 3 is greater than 300 °C, indicating that they have good heat resistance. This is because the reaction system of Examples 1 and 3 reacts more fully, and the increase in crosslinking degree and molecular weight restricts the movement of the molecular chains of the product, thus making T 50％It increases. At the same time, the carbon residue rates of Example 1 and Example 3 at 700 °C are relatively low because the cured films of Example 1 and Example 3 are more likely to generate gas products during the thermal degradation process. Although the weight loss of the cured films of Example 2 and Example 4 reaches 50% at around 250 °C, their carbon residue rates at 700 °C are greater than 9% because, compared with other examples of the present invention, the cured films of Example 2 and Example 4 first undergo chain segment breakage and release of small molecules at lower temperatures and then undergo carbonization reactions at higher temperatures.

[0079] Table 2 Thermal decomposition data of the cured film

[0080] Sample <![CDATA[T 5％ (℃)]]> <![CDATA[T 50％ (℃)]]> <![CDATA[T max (1 st / 2 nd )(°C)]]> Residual Carbon Content Rate (%) Example 1 233.8 303.3 342.7 / 400.8 2.44 Example 2 237.9 264.4 316.4 / 380.4 10.64 Example 3 278.7 307.2 324.2 / 396.7 0.79 Example 4 242.3 266.3 291.8 / 377.8 9.53

[0081] Experimental Example 4

[0082] In this experimental example, the printing coatings of Examples 5 to 8 were respectively coated on cotton cloth and swimsuit fabric, and then the cotton cloth and swimsuit fabric were overheated at 135 °C for 30 seconds. The color degree of the printing on the cotton cloth before and after overheating was observed by visual inspection. The results are as Figure 6 and Figure 7 shown. It can be observed that the printing coating of the present invention is brightly colored on the cotton cloth and shows no obvious fading after overheating at 135 °C, indicating that the printing coating has good thermal stability and can be printed on fabrics. By touching the fabric, it was found that the fabric treated with the printing coating has a soft handfeel.

[0083] According to GB / T 3921-2008 "Textiles - Tests for colour fastness - Colour fastness to soaping", the washing fastness of the swimsuit fabric coated with the printing coating was tested. The experimental conditions for the test were that the swimsuit fabric coated with the printing coatings of Examples 5 to 8 was immersed in water, 5 g of phosphorus-free washing powder was added, and it was washed standardly for 2.5 h in a mechanical washing device at a water temperature of 60 °C and a rotation speed of 1200 r / min.

[0084] According to the test methods of rubbing fastness (dry and wet) in GB / T 3920-2008 "Textiles - Tests for colour fastness - Colour fastness to rubbing", the dry and wet rubbing fastnesses of the cotton cloth coated with the printing coatings of Examples 5 to 8 were tested.

[0085] Table 3 Dry rubbing fastness, wet rubbing fastness and washing fastness of the fabric

[0086] Dry Rub Fastness Wet Rub Fastness Washing Fastness Example 5 4 4-5 4 Example 6 3-4 3-4 3-4 Example 7 3-4 4 4 Example 8 3-4 4 3-4

[0087] As can be seen from Table 3, the swimwear fabrics coated with the printing coatings of Examples 5 to 8 were rated 3-4 after the machine wash fastness test, indicating that the printing coatings were firmly bonded to the swimwear fabrics (usually chemical fibers). The dry rubbing fastness of the cotton fabrics coated with the printing coatings of Examples 5 to 8 was rated 3-4 in the dry rubbing fastness test, indicating that the printing coatings of the present invention had a strong binding force with cotton fibers and were not easily detached due to friction. Moreover, the wet rubbing fastness was rated 3-5, indicating that the printing coatings were not easily dissolved in water. The above tests show that the printing coating slurry of the present invention has good adhesion and water resistance and can be coated on fabrics.

[0088] Therefore, compared with the prior art, the beneficial effects of the present invention are as follows: The bio-based PDI aqueous polyurethane emulsion prepared by reacting the first bio-based polyol, the second bio-based polyol with 1,5-pentane diisocyanate reduces the use of petroleum resources as raw materials and increases the bio-based content in the aqueous polyurethane emulsion, which is green and environmentally friendly. At the same time, the emulsion stability of the bio-based PDI aqueous polyurethane emulsion prepared by the present invention is good. In addition, the cured film formed after curing the bio-based PDI aqueous polyurethane emulsion of the present invention has good tensile properties and thermal stability. The bio-based PDI aqueous polyurethane emulsion of the present invention can be used to prepare a printing coating. The fabric treated with the printing coating has bright colors, soft handfeel, and good results in the machine wash fastness test and the dry and wet rubbing fastness tests.

[0089] The above are only some embodiments of the present invention. For those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention.

Claims

1. A bio-based PDI aqueous polyurethane emulsion, characterized in that, Prepared from a system formed by the following components in parts by weight: 70 - 90 parts of a first bio - based polyol, 30 - 50 parts of a second bio - based polyol, 25 - 45 parts of 1,5 - pentane diisocyanate, 0.5 - 2.5 parts of a catalyst, 4 - 6 parts of a neutralizing agent, and 2 - 10 parts of a hydrophilic chain extender; Wherein, the first bio - based polyol and the second bio - based polyol are each independently selected from any one of polypropylene glycol, polycarbonate diol, or polylactic acid polyol.

2. A bio-based PDI aqueous polyurethane emulsion, characterized in that, Prepared from a system formed by the following components in parts by weight: 70 - 90 parts of a first bio - based polyol, 30 - 50 parts of a second bio - based polyol, 25 - 45 parts of 1,5 - pentane diisocyanate, 0.5 - 2.5 parts of a catalyst, 4 - 6 parts of a neutralizing agent, 2 - 10 parts of a hydrophilic chain extender, and 6 - 11 parts of a small - molecule chain extender; Wherein, the first bio - based polyol and the second bio - based polyol are each independently selected from any one of polypropylene glycol, polycarbonate diol, or polylactic acid polyol.

3. The bio-based PDI aqueous polyurethane emulsion according to claim 1 or 2, characterized in that The hydrophilic chain extender is at least one of 2,2 - dimethylolpropionic acid, 2,2 - dimethylolbutyric acid, or glycerol tartrate; the small - molecule chain extender is any one or two of PEG, diethylenediamine, ethylenediamine, or hydrazine hydrate, and the number - average molecular weight of the PEG is 200 - 600.

4. The bio-based PDI aqueous polyurethane emulsion according to claim 3, wherein The neutralizing agent is any one of triethylamine, dimethylaminoethanol, or triethanolamine, and the molar ratio of the neutralizing agent to the carboxyl group in the system is (0.9 - 1.1):1; the catalyst is an organic bismuth.

5. The preparation method of the bio-based PDI aqueous polyurethane emulsion according to any one of claims 1 to 4, characterized in that, The preparation method includes the following steps: S1. Add the first bio - based polyol and the second bio - based polyol into a reactor, carry out a vacuum dehydration reaction in a nitrogen atmosphere, then cool down to 60 °C - 70 °C, add 1,5 - pentane diisocyanate into the reactor, carry out a constant - temperature reaction at 80 °C - 85 °C for 1.5 - 3 h, cool down to 55 °C - 65 °C, then add the catalyst and the chain - extending reagent into the reactor, carry out a constant - temperature reaction at 60 °C - 80 °C for 3 - 5 h, then add an organic solvent, and cool down to 45 - 55 °C to obtain a bio - based PDI polyurethane prepolymer; S2. Add the neutralizing agent to the bio - based PDI polyurethane prepolymer for neutralization for 8 - 12 min, add deionized water for an emulsification reaction, and remove the organic solvent under vacuum at 40 - 50 °C to obtain the product; Wherein, the organic solvent is any one of acetone or butanone; The chain - extending reagent is a hydrophilic chain extender, or, the chain - extending reagent is a hydrophilic chain extender and a small - molecule chain extender.

6. The preparation method of the bio-based PDI aqueous polyurethane emulsion according to claim 5, characterized in that, In step S1, the treatment method for vacuum dehydration is to carry out vacuum dehydration for 1 - 2 h under the conditions of a temperature of 100 - 120 °C and a vacuum degree greater than 0.085 MPa.

7. The preparation method of the bio-based PDI aqueous polyurethane emulsion according to claim 5, characterized in that, In step S2, the treatment method for the emulsification reaction is: First, disperse at a speed of 1800 - 2200 r / min for 4 - 6 min, then add the small - molecule chain extender, and then disperse at a speed of 900 - 1100 r / min for 0.8 - 1.2 h; Or, first disperse at a speed of 1800 - 2200 r / min for 4 - 6 min, and then disperse at a speed of 900 - 1100 r / min for 0.8 - 1.2 h; Or, after neutralizing the bio-based PDI polyurethane prepolymer with a neutralizing agent, first add a small molecule chain extender, then add deionized water, disperse at a rotation speed of 1800-2200 r / min for 4-6 min, and then disperse at a rotation speed of 900-1100 r / min for 0.8-1.2 h.

8. Application of the bio-based PDI aqueous polyurethane emulsion according to any one of claims 1 to 4 in printing coatings.

9. The application according to claim 8, wherein Based on parts by weight, the printing coating comprises the following components: 80-90 parts of the bio-based PDI aqueous polyurethane emulsion, 0.5-1.5 parts of an antifoaming agent, 2-4 parts of a thickener, and 8-12 parts of a color paste.

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