A carbon dioxide-based aqueous polyurethane and its preparation method and application

Abstract

The present invention relates to the field of new waterborne polyurethane materials, and in particular to a carbon dioxide-based waterborne polyurethane and its preparation method and application. The raw materials for preparing the carbon dioxide-based waterborne polyurethane include the following components in parts by mass: 80-130 parts of carbon dioxide-based polyol, 25-60 parts of isophorone diisocyanate, 4-10 parts of dimethylolpropionic acid, and 2-10 parts of neutralizing agent; wherein, the carbon dioxide-based polyol is a carbon dioxide-based polycarbonate polyol polymerized from carbon dioxide and an epoxide, and the molecular weight is 1500-2500. The carbon dioxide-based waterborne polyurethane has the advantages of stability, high solid content, low viscosity, and high strength.

Description

Technical Field

[0001] The present invention relates to the field of new waterborne polyurethanes, and particularly to a carbon dioxide-based waterborne polyurethane and its preparation method and application. Background Art

[0002] Waterborne polyurethane resin is a type of environmentally friendly new material. Using water as the medium and containing no organic solvents, its greatest feature is being green and pollution-free, and being environmentally friendly during use. According to different formulations and usage requirements, it can be applied in multiple fields. However, there are still significant differences between waterborne polyurethanes and oil-based polyurethanes in some fields. Currently, most waterborne polyurethanes with good performance have a relatively low solid content (30 - 40 wt%), and they do not have an advantage in terms of product packaging, storage, and transportation costs. In addition, a low solid content means that water volatilizes, resulting in a long drying time and low production efficiency, which is not conducive to applications in many fields. Generally speaking, under the condition that the stability and construction performance of the emulsion are normal, the higher the solid content, the more obvious the competitive advantage. Many application fields such as adhesives, leather, and wood coatings require waterborne polyurethanes with a relatively high solid content to meet performance requirements.

[0003] High-solid-content waterborne polyurethane resin has always been one of the current research hotspots. Currently, the research on preparing high-solid-content waterborne polyurethanes mostly focuses on sulfonic acid-based waterborne polyurethanes. However, for the waterborne polyurethane resin prepared by sulfonates, due to the presence of sulfonate groups with extremely good hydrophilic properties in the molecule, its water resistance and solvent resistance often perform poorly.

[0004] Carbon dioxide-based polyol (PPCD) is an environmentally friendly new polyol with low price and excellent performance. The polyurethane products prepared from it have better mechanical properties than those prepared from conventional polyester-based or polyether-based polyols, and have good hydrolysis resistance. Therefore, it has broad industrial application prospects. However, the waterborne polyurethane prepared from carbon dioxide-based polyol has a relatively low solid content, and the preparation process often requires a relatively high temperature and a long time. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. For this reason, the present invention provides a carbon dioxide-based waterborne polyurethane and its preparation method and application. This carbon dioxide-based waterborne polyurethane has the advantages of being stable, having a high solid content, low viscosity, and high strength.

[0006] In the first aspect of the present invention, there is provided a carbon dioxide-based waterborne polyurethane, and the preparation raw materials include the following components in parts by mass:

[0007] 80 - 130 parts of carbon dioxide-based polyol;

[0008] 25 - 60 parts of isophorone diisocyanate;

[0009] 4-10 parts of dimethylolpropionic acid;

[0010] 2-10 parts of neutralizing agent;

[0011] The carbon dioxide-based polyol is a carbon dioxide-based polycarbonate polyol polymerized from carbon dioxide and an epoxide, with a molecular weight of 1500-2500.

[0012] According to some embodiments of the present invention, the epoxide is propylene oxide or ethylene oxide, preferably propylene oxide.

[0013] According to some embodiments of the present invention, the carbon dioxide-based polyol has a hydroxyl functionality of 2 and a molar fraction of the carbonate group in the molecule of 0.2-0.4.

[0014] According to some embodiments of the present invention, the viscosity (40 °C) of the carbon dioxide-based polyol is 4000-6000 mPa·s, and the hydroxyl value is 50-60 mgKOH / g.

[0015] According to some embodiments of the present invention, the raw materials for preparing the carbon dioxide-based aqueous polyurethane further include a catalyst, and the mass fraction of the catalyst is 0.2-0.4 parts.

[0016] According to some embodiments of the present invention, the raw materials for preparing the carbon dioxide-based aqueous polyurethane include the following components in parts by mass:

[0017] 110-130 parts of carbon dioxide-based polyol;

[0018] 30-60 parts of isophorone diisocyanate;

[0019] 8-10 parts of dimethylolpropionic acid;

[0020] 3-6 parts of neutralizing agent;

[0021] 0.2-0.3 parts of catalyst.

[0022] According to some embodiments of the present invention, the neutralizing agent is at least one of triethylamine, tripropylamine, tributylamine, sodium hydroxide, and ammonia water;

[0023] Preferably, the neutralizing agent is triethylamine.

[0024] According to some embodiments of the present invention, the catalyst is at least one of stannous octoate, dibutyltin dilaurate, tin acetate, and organic bismuth;

[0025] Preferably, the catalyst is organic bismuth, which is an environmentally friendly catalyst.

[0026] The reactivity of carbon dioxide-based polyols is relatively low, the required synthesis temperature is relatively high, and the synthesis time is relatively long. The use of organobismuth catalysts can effectively catalyze the reaction.

[0027] According to some embodiments of the present invention, the solid content of the carbon dioxide-based aqueous polyurethane is 40% to 55%.

[0028] In a second aspect of the present invention, there is provided a method for preparing the above-mentioned carbon dioxide-based aqueous polyurethane, comprising the following steps:

[0029] S1. According to the ratio, mix the carbon dioxide-based polyol, isophorone diisocyanate, and dimethylolpropionic acid. If there is a catalyst, add the catalyst and mix; cool down to obtain a carbon dioxide-based polyurethane prepolymer.

[0030] S2. Mix the carbon dioxide-based polyurethane prepolymer obtained in step S1 with the neutralizing agent, carry out emulsification, and after cooling, obtain the product.

[0031] According to some embodiments of the present invention, in step S1, the mixing temperature is 100 to 120°C, the mixing time is 4 to 6 h, and the temperature is cooled down to 40 to 70°C.

[0032] According to some embodiments of the present invention, in step S2, the emulsification temperature is 10 to 25°C, and the emulsification time is 10 to 60 min.

[0033] In a third aspect of the present invention, there is provided a coating, and the preparation raw materials include the above-mentioned carbon dioxide-based aqueous polyurethane.

[0034] Beneficial effects:

[0035] The present invention uses carbon dioxide-based polyols, isophorone diisocyanate, and dimethylolpropionic acid as the main raw materials. Through formula design, the neutralization amount in the system is adjusted, the carboxyl neutralization degree of the system is adjusted to 50% - 100%, and the hydrophilic performance of the hydrophilic monomers in the structure is controlled to prepare a latex system with different particle sizes (80 - 450 nm). The particle size has a great influence on the effective space of the aqueous system. The wider the particle size range, the more effective space, and the more conducive to the preparation of an aqueous polyurethane emulsion with a high solid content and low viscosity; however, if the particle size is large, the phenomenon of emulsion instability will occur.

[0036] Specifically, the present invention uses carbon dioxide-based polyols as the preparation raw materials, which are different from traditional chemical polyol materials. They are prepared from carbon dioxide gas, and the materials contain a large number of carbonate bonds, with good mechanical properties and low cost. Large-scale production can effectively utilize gaseous carbon dioxide, which is of great significance for environmental protection, energy conservation, and emission reduction; in addition, the advantage of using dimethylolpropionic acid as a hydrophilic functional monomer is that it has more stable performance, good water resistance, and low preparation cost.

[0037] In summary, the carbon dioxide-based aqueous polyurethane emulsion of the present invention can effectively increase the solid content of the emulsion, reduce costs, and at the same time ensure that the aqueous polyurethane emulsion has good comprehensive properties.

[0038] In the present invention, "mole fraction" refers to the percentage of the carbon dioxide mole content in the total moles of the system.

[0039] Other features and advantages of the present invention will be described in the subsequent specification, and, in part, will become apparent from the specification or will be understood by practicing the present invention. Detailed implementation modes

[0040] The following will clearly and completely describe the concept and technical effects generated by the present invention in combination with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts shall fall within the scope of protection of the present invention.

[0041] The design idea of the present invention is as follows: The neutralizing agent neutralizes the carboxyl groups in the system to form salts, making the prepolymer have hydrophilic properties. By adjusting the dosage of the neutralizing agent, the hydrophilic properties of the prepolymer can be changed, and the hydrophilic degree in the water system can be controlled, so as to disperse into emulsions with different particle sizes. In this way, an aqueous polyurethane emulsion with high solid content and low viscosity can be prepared.

[0042] The carbon dioxide-based polyol used in the present invention is a carbon dioxide-based poly(propylene carbonate) diol polymerized from carbon dioxide and propylene oxide, which can be obtained from commercially available products. For example, the product with the product number PPCD222 from Huizhou Dayawan Dazhi Fine Chemical Co., Ltd.

[0043] It should be noted that due to the errors in both water evaporation and prepolymer loss, there will be differences between the actual test results of the solid content recorded in the examples and the comparative examples and the theoretical values.

[0044] Example 1

[0045] Take 120 parts of carbon dioxide - based diol with a molecular weight of 2000, a hydroxyl functionality of 2, a viscosity (at 40 °C) of 6000 mPa·s, a hydroxyl value of 56 mg KOH / g, and a molar fraction of carbonate groups in the molecule of 26%. After dehydration under high temperature and vacuum, add 40 parts of isophorone diisocyanate, 8.4 parts of dimethylolpropionic acid, and 0.24 parts of organic bismuth catalyst. React at 105 °C for 4 hours to obtain a polyurethane prepolymer. Cool down to 45 °C, add 5.4 parts of neutralizing agent triethylamine, react for 10 minutes, add 250 parts of deionized water, and carry out an emulsification reaction at 10 - 25 °C for 30 minutes to obtain a carbon dioxide - based aqueous polyurethane emulsion with a solid content of 40%.

[0046] Example 2

[0047] Take 120 parts of carbon dioxide - based diol with a molecular weight of 2000, a hydroxyl functionality of 2, a viscosity (at 40 °C) of 6000 mPa·s, a hydroxyl value of 56 mg KOH / g, and a molar fraction of carbonate groups in the molecule of 26%. After dehydration under high temperature and vacuum, add 45 parts of isophorone diisocyanate, 9 parts of dimethylolpropionic acid, and 0.24 parts of organic bismuth catalyst. React at 105 °C for 4 hours to obtain a polyurethane prepolymer. Cool down to 45 °C, add 5 parts of neutralizing agent triethylamine, react for 10 minutes, add 215 parts of deionized water, and carry out an emulsification reaction at 10 - 25 °C for 30 minutes to obtain a carbon dioxide - based aqueous polyurethane emulsion with a solid content of 45%.

[0048] Example 3

[0049] Take 120 parts of carbon dioxide - based diol with a molecular weight of 2000, a hydroxyl functionality of 2, a viscosity (at 40 °C) of 6000 mPa·s, a hydroxyl value of 56 mg KOH / g, and a molar fraction of carbonate groups in the molecule of 26%. After dehydration under high temperature and vacuum, add 45 parts of isophorone diisocyanate, 9 parts of dimethylolpropionic acid, and 0.24 parts of organic bismuth catalyst. React at 105 °C for 4 hours to obtain a polyurethane prepolymer. Cool down to 45 °C, add 4.5 parts of neutralizing agent triethylamine, react for 10 minutes, add 175 parts of deionized water, and carry out an emulsification reaction at 10 - 25 °C for 30 minutes to obtain a carbon dioxide - based aqueous polyurethane emulsion with a solid content of 50%.

[0050] Example 4

[0051] Take 120 parts of carbon dioxide - based diol with a molecular weight of 2000, a hydroxyl functionality of 2, a viscosity (at 40 °C) of 6000 mPa·s, a hydroxyl value of 56 mg KOH / g, and a molar fraction of carbonate groups in the molecule of 26%. After dehydration under high temperature and vacuum, add 50 parts of isophorone diisocyanate, 9 parts of dimethylolpropionic acid, and 0.24 parts of organobismuth catalyst, and react at 105 °C for 4 hours to obtain a polyurethane prepolymer. Cool down to 45 °C, add 4 parts of the neutralizer triethylamine, react for 10 minutes, add 145 parts of deionized water, and carry out an emulsification reaction at 10 - 25 °C for 30 minutes to obtain a carbon dioxide - based aqueous polyurethane emulsion with a solid content of 55%.

[0052] Comparative Example 1

[0053] Take 120 parts of carbon dioxide - based diol with a molecular weight of 2000, a hydroxyl functionality of 2, a viscosity (at 40 °C) of 6000 mPa·s, a hydroxyl value of 56 mg KOH / g, and a molar fraction of carbonate groups in the molecule of 26%. After dehydration under high temperature and vacuum, add 40 parts of isophorone diisocyanate, 8.4 parts of dimethylolbutyric acid (DMBA), and 0.24 parts of organobismuth catalyst, and react at 105 °C for 4 hours to obtain a polyurethane prepolymer. Cool down to 45 °C, add 4.4 parts of the neutralizer triethylamine, react for 10 minutes, add 250 parts of deionized water, and carry out an emulsification reaction at 10 - 25 °C for 30 minutes to obtain a carbon dioxide - based aqueous polyurethane emulsion with a solid content of 40%.

[0054] Comparative Example 2

[0055] Take 120 parts of commercially available polyether diol. After dehydration under high temperature and vacuum, add 40 parts of isophorone diisocyanate, 8.4 parts of dimethylolpropionic acid, and 0.24 parts of organobismuth catalyst, and react at 105 °C for 4 hours to obtain a polyurethane prepolymer. Cool down to 45 °C, add 6.4 parts of the neutralizer triethylamine, react for 10 minutes, add 205 parts of deionized water, and carry out an emulsification reaction at 10 - 25 °C for 30 minutes to obtain an aqueous polyurethane emulsion with a solid content of 45%.

[0056] Comparative Example 3

[0057] Take 120 parts of carbon dioxide - based diol with a molecular weight of 3000, a hydroxyl functionality of 2, a viscosity (at 40 °C) of 10000 mPa·s, a hydroxyl value of 37 mg KOH / g, and a molar fraction of carbonate groups in the molecule of 31%. After dehydration under high temperature and vacuum, add 45 parts of isophorone diisocyanate, 9 parts of dimethylolpropionic acid, and 0.24 parts of organobismuth catalyst, and react at 105 °C for 4 hours to obtain a polyurethane prepolymer. Cool down to 45 °C, add 5 parts of the neutralizer triethylamine, react for 10 minutes, add 210 parts of deionized water, and carry out an emulsification reaction at 10 - 25 °C for 30 minutes to obtain a carbon dioxide - based aqueous polyurethane emulsion with a solid content of 45%.

[0058] Comparative Example 4

[0059] Take 120 parts of carbon dioxide - based diol with a molecular weight of 1000, a hydroxyl functionality of 2, a viscosity (at 40 °C) of 5000 mPa·s, a hydroxyl value of 112 mg KOH / g, and a molar fraction of carbonate groups in the molecule of 23%. After dehydration under high temperature and vacuum, add 65 parts of isophorone diisocyanate, 9 parts of dimethylolpropionic acid, and 0.24 parts of organobismuth catalyst. React at 105 °C for 4 hours to obtain a polyurethane prepolymer. Cool down to 45 °C, add 5 parts of neutralizing agent triethylamine, react for 10 minutes, add 235 parts of deionized water, and carry out an emulsification reaction at 10 - 25 °C for 30 minutes to obtain a carbon dioxide - based aqueous polyurethane emulsion with a solid content of 45%.

[0060] Comparative Example 5

[0061] Take 120 parts of carbon dioxide - based diol with a molecular weight of 2000, a hydroxyl functionality of 2, a viscosity (at 40 °C) of 6000 mPa·s, a hydroxyl value of 56 mg KOH / g, and a molar fraction of carbonate groups in the molecule of 26%. After dehydration under high temperature and vacuum, add 40 parts of hexamethylene diisocyanate, 8.4 parts of dimethylolpropionic acid, and 0.24 parts of organobismuth catalyst. React at 105 °C for 4 hours to obtain a polyurethane prepolymer. Cool down to 45 °C, add 5.4 parts of neutralizing agent triethylamine, react for 10 minutes, add 250 parts of deionized water, and carry out an emulsification reaction at 10 - 25 °C for 30 minutes to obtain a carbon dioxide - based aqueous polyurethane emulsion with a solid content of 40%.

[0062] Comparative Example 6

[0063] Take 120 parts of carbon dioxide - based diol with a molecular weight of 3000, a hydroxyl functionality of 2, a viscosity (at 40 °C) of 10000 mPa·s, a hydroxyl value of 37 mg KOH / g, and a molar fraction of carbonate groups in the molecule of 31%. After dehydration under high temperature and vacuum, add 45 parts of hydrogenated diphenylmethane diisocyanate, 9 parts of dimethylolpropionic acid, and 0.24 parts of organobismuth catalyst. React at 105 °C for 4 hours to obtain a polyurethane prepolymer. Cool down to 45 °C, add 5 parts of neutralizing agent triethylamine, react for 10 minutes, add 215 parts of deionized water, and carry out an emulsification reaction at 10 - 25 °C for 30 minutes to obtain a carbon dioxide - based aqueous polyurethane emulsion with a solid content of 45%.

[0064] Test Example

[0065] Based on the following test standards, the aqueous polyurethanes prepared in the above Examples 1-4 and Comparative Examples 1-6 were tested respectively: The appearance of the emulsion was observed by visual inspection to compare the color, permeability, and presence or absence of precipitation of the emulsion; the solid content of the emulsion was directly measured by a moisture and solid content meter; the pH value was tested by the general method for determining the pH value in aqueous solutions of GB / T 23769-2009; the particle size was measured using a ZETA potentiometer to measure the particle size of the emulsion; the gloss of the paint film was measured using a 60° angle luminance meter; the storage stability of the emulsion was tested according to the method described in GB / T 23999-2009; the tensile properties of the emulsion film were tested using an electronic tensile machine to measure the stress-strain curve of the resin. The pre-prepared film was tested according to the GB / T 13022 standard, applied to dumbbell-shaped and strip-shaped sample types, and for the tensile property test conditions of plastic films and plastic sheets with a thickness less than 1 mm, the tensile speed was 200 mm / min.

[0066] The test results of the aqueous polyurethanes prepared in Examples 1-4 are shown in Table 1.

[0067] Table 1

[0068]

[0069] The test results of the aqueous polyurethanes prepared in Comparative Examples 1-6 are shown in Table 2.

[0070] Table 2

[0071]

[0072]

[0073] As can be seen from Table 1, the carbon dioxide aqueous polyurethanes prepared in Examples 1-4 all have properties such as stability and excellent tensile strength, and they all have a relatively high solid content, up to 55% in Example 4. The reason why Example 4 has such a high solid content is mainly because during the synthesis process, by adjusting the dosage of the neutralizing agent, unsaturated neutralization was carried out with the carboxyl groups in the hydrophilic monomer, preparing latex particles with a wider particle size distribution and larger particle size, and finally obtaining a carbon dioxide-based aqueous polyurethane with a high solid content.

[0074] As can be seen from Table 2, in Comparative Example 1, dimethylolbutyric acid was used as the hydrophilic monomer. Although the solid content of the prepared aqueous polyurethane reached 40%, the emulsion viscosity was relatively high, which was not conducive to construction and use. Demulsification and slagging would occur during long-term storage. At the same time, the price of dimethylolbutyric acid was relatively high, which was not conducive to large-scale use in the market.

[0075] In Comparative Example 2, traditional polyether polyols were used to prepare high-solid-content aqueous polyurethanes, but there were problems such as a relatively large system viscosity and low mechanical strength.

[0076] Comparative Examples 3 and 4 used carbon dioxide-based polyols with different molecular weights (1000, 3000) to prepare aqueous polyurethanes with a solid content of 45%. Comparing with Example 2, it can be seen that the polyurethane prepared from the carbon dioxide-based polyol with a molecular weight of 2000 has the lowest viscosity and the best performance.

[0077] Comparative Examples 5 and 6 used different types of isocyanates to prepare carbon dioxide-based aqueous polyurethanes with different solid contents. Comparing with Example 1 and Comparative Example 3 respectively, it can be seen that the carbon dioxide-based aqueous polyurethane prepared with isophorone diisocyanate has the highest solid content, a stable emulsion system, and the highest mechanical properties among the same type.

[0078] In summary, the present invention meets the actual use requirements, can be applied to fields with requirements for solid content, and has a great promoting effect on the market application of carbon dioxide-based aqueous polyurethane resins.

[0079] The above content has described the embodiments of the present invention in detail. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge scope of those of ordinary skill in the art. In addition, without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

Claims

1. A carbon dioxide-based aqueous polyurethane, characterized in that The preparation raw materials are composed of the following components in parts by mass: 80 - 130 parts of carbon dioxide - based polyol; 25 - 60 parts of isophorone diisocyanate; 4 - 10 parts of dimethylolpropionic acid; 2 - 10 parts of neutralizer; 0.2 - 0.4 parts of organic bismuth; The carbon dioxide - based polyol is a carbon dioxide - based polycarbonate polyol polymerized from carbon dioxide and epoxy compounds, with a molecular weight of 1500 - 2500, a viscosity of 4000 - 6000 mPa·s at 40°C, and a hydroxyl value of 50 - 60 mgKOH / g; The solid content of the carbon dioxide - based water - borne polyurethane is 40% - 55%.

2. The carbon dioxide-based aqueous polyurethane according to claim 1, wherein The hydroxyl functionality of the carbon dioxide - based polyol is 2, and the molar fraction of the carbonate group in the molecule is 0.2 - 0.

4.

3. The carbon dioxide-based aqueous polyurethane according to claim 1, wherein The neutralizer is at least one of triethylamine, tripropylamine, tributylamine, sodium hydroxide, and ammonia water.

4. The carbon dioxide-based aqueous polyurethane according to claim 3, wherein The neutralizer is triethylamine.

5. The preparation method of the carbon dioxide-based aqueous polyurethane according to any one of claims 1 to 4, characterized in that, It includes the following steps: S1. Mix the carbon dioxide - based polyol, isophorone diisocyanate, dimethylolpropionic acid, and organic bismuth according to the ratio; cool to obtain a carbon dioxide - based polyurethane prepolymer; S2. Mix the carbon dioxide - based polyurethane prepolymer obtained in step S1 with the neutralizer, carry out emulsification, and after cooling, it is obtained.

6. The preparation method according to claim 5, wherein In step S1, the mixing temperature is 100 - 120°C, the mixing time is 4 - 6 h, and it is cooled to 40 - 70°C.

7. The preparation method according to claim 5, wherein In step S2, the emulsification temperature is 10 - 25°C, and the emulsification time is 10 - 60 min.

8. A coating, characterized in that, The preparation raw materials include the carbon dioxide - based water - borne polyurethane according to any one of claims 1 - 4.

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