A self-healing polyurethane composition and a method for preparing the same

Abstract

The application belongs to the technical field of polyurethane compositions, and specifically provides a self-repairing polyurethane composition and a preparation method thereof, which is obtained by mixing and processing raw materials including the following components by mass: polycaprolactone diol 50-60 parts, isocyanate 15-20 parts, leveling agent 0.5-2 parts, light stabilizer 1-2 parts, composite solvent 20-30 parts, lipid-based-copper complex crystallization body 2-5 parts, butanedione oxime 5-8 parts, and catalyst 0.01-0.05 parts; the lipid-based-copper complex crystallization body is obtained by crystallization after mixing hydrogenated castor oil and a copper complex body. The self-repairing polyurethane composition coating prepared by the application has the advantages of stain resistance, anti-cracking, and folding resistance.

Description

Technical Field

[0001] This application belongs to the field of polyurethane composition technology, and in particular relates to a self-healing polyurethane composition and its preparation method. Background Technology

[0002] Self-healing polyurethane material is a new type of smart material. In the field of coatings, it overcomes the problems of traditional coatings being easily damaged by external factors and having poor durability. It can repair damaged parts on its own, extend service life, and reduce maintenance costs. It has been applied to protective coatings in the automotive, shipbuilding, and electronics industries.

[0003] Self-healing polyurethane materials, as advanced soft-segment-hard-segment block copolymers, have their overall performance fundamentally determined by their structural design. The soft segments are typically polyester or polycaprolactone-based polyols, imparting good flexibility, ductility, and molecular chain mobility. The hard segments are mainly composed of isocyanate curing agents, providing the necessary mechanical strength, thermal stability, and structural support. The ratio of soft to hard segments and their microstructure directly affect the material's glass transition temperature, modulus, elasticity, and durability, and are key to achieving tunable performance. The core mechanism behind the self-healing capability of these materials lies in the reversible dynamic chemical bonds introduced into their system. For example, oxime ester bonds can undergo reversible breakage and recombination under mild conditions; borate ester bonds can undergo dynamic exchange reactions in the presence of water or alcohol; and dynamic disulfide bonds can be rebuilt through redox reactions or thermal excitation. When a material is damaged by external forces and develops microcracks, these dynamic bonds can undergo reversible reactions under suitable conditions, driving the molecular chains to rearrange and connect, and promoting the reformation of chemical bonds at the damaged interface. This enables the autonomous healing of microcracks and the restoration of macroscopic functions, significantly extending the service life of the material and improving its reliability and safety.

[0004] To optimize the repair effect, copper ions can be introduced into the polyurethane matrix to form metal coordination bonds. Copper ions synergistically interact with dynamic bonds such as oxime ester bonds, enhancing the reversibility of dynamic bonds, accelerating the repair rate, increasing crosslinking points, and improving mechanical properties. However, copper ions exhibit poor dispersion in the organic phase, easily agglomerating in the polyurethane to form stress concentration points, exacerbating coating cracking and surface matting. They also reduce the coating's stain resistance and weather resistance, accelerating aging. Therefore, it is necessary to find a self-healing polyurethane composition and its preparation method that reduces copper ion agglomeration while improving the coating's stain resistance, crack resistance, and matting resistance. Summary of the Invention

[0005] To address the aforementioned issues and further reduce the aggregation of copper ions in the polyurethane matrix, thereby enhancing toughness and stain resistance, this application provides a self-healing polyurethane composition and its preparation method.

[0006] This application first provides a method for preparing a self-healing polyurethane composition, which is obtained by mixing raw materials comprising the following parts by weight: 50-60 parts of polycaprolactone diol, 15-20 parts of isocyanate, 0.5-2 parts of leveling agent, 1-2 parts of light stabilizer, 20-30 parts of composite solvent, 2-5 parts of aliphatic-copper complex crystals, 5-8 parts of dimethylglyoxime, and 0.01-0.05 parts of catalyst; The preparation steps of the aliphatic-copper complex crystal include the following: S01. Take hydrogenated castor oil and copper complex, mix them, add acetone and preheat to disperse, to obtain solution A; the mass-to-volume ratio of hydrogenated castor oil, copper complex and acetone used is (0.5-0.8)g:(0.1-0.15)g:(4-5)mL; S02. Take anhydrous ethanol, preheat it, and obtain solution B; S03. Mix solution A and solution B, sonicate, cool to crystallize, then centrifuge to collect the precipitate, and dry to obtain the final product; In step S03, liquid A and liquid B are mixed at a volume ratio of 1:(10-12); the ultrasound is set to pulse mode, 10-30s, and power is 300W. In step S03, the cooling crystallization is programmed to cool to room temperature at a rate of 0.5-1.0℃ / min, and then left to stand overnight; The composite solvent is obtained by mixing butyl acetate and propylene glycol methyl ether acetate in a volume ratio of (4-5):1.

[0007] The preparation steps of the copper complex include the following: Take stearic acid, disperse it, heat it and add oxaloyl chloride, then cool it down to react, then add 8-hydroxyquinoline, continue stirring to react, then rotary evaporate it, transfer the product to the impregnation solution, stir it, and finally separate the aqueous phase to obtain the product; The mass-to-volume ratio of stearic acid, oxaloyl chloride, and 8-hydroxyquinoline used is (5.2-5.5) g:(1.5-1.7) mL:(3-3.2) g; The impregnation solution is a copper sulfate solution with a mass concentration of 1.5%-2%.

[0008] This application also provides a self-healing polyurethane composition prepared by the above-described preparation method.

[0009] Compared with the prior art, this application has the following beneficial effects: 1. The copper complex prepared in this application inhibits the aggregation of copper ions in polyurethane through saturated coordination, thereby promoting the self-healing process of the polyurethane material. Furthermore, by introducing this complex during the cooling crystallization process of hydrogenated castor oil, some copper ions react with the hydroxyl or ester groups of the hydrogenated castor oil molecules to form heterogeneous nucleation sites. This not only accelerates the construction of the three-dimensional crystalline network of hydrogenated castor oil but also enhances the stability of the crystallized product in the polyurethane coating. As a toughening phase, this crystallization can improve the polyurethane composition's resistance to tensile stress and reduce the risk of coating cracking.

[0010] 2. The hydrogenated castor oil crystals obtained through this application have hydrophobic properties, which can directly impart good anti-fouling properties to the coating surface. At the same time, some copper complex segments extending from the crystal surface can interpenetrate with the polyurethane matrix to form an interpenetrating network structure, which enhances the compatibility between the toughening phase and the matrix and avoids problems such as coating cracking or folding and dulling caused by phase separation. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the self-healing polyurethane composition coating structure of this application. The corresponding component names of each reference numeral in the figure are: 1-self-healing polyurethane composition coating; 2-substrate layer.

[0012] Figure 2 The data are the antifouling test data of the self-healing polyurethane composition coatings of Examples 1-3 and Comparative Examples 1-2 of this application. Detailed Implementation

[0013] To make the inventive objectives, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0014] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0015] When using “including,” “having,” and “contains” as described herein, the intention is to cover non-exclusive inclusion, unless an explicit qualifying term such as “only,” “consisting of,” etc., is used, in which case another component may be added.

[0016] The terms "preferred," "more preferably," "better," and "even better" used in this application refer to embodiments of this application that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this application. That is, in this application, "preferred," "more preferably," "better," and "even better" are merely descriptions of implementations or embodiments with better effects, but do not constitute a limitation on the scope of protection of this application.

[0017] In this application, terms such as "further," "even more," and "particularly" are used for descriptive purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0018] In this application, "at least one" means one or more, such as one, two, or more. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layered" means at least two layers, such as two layers, three layers, etc., unless otherwise explicitly specified. In the description of this application, "several" means at least one, such as one, two, etc., unless otherwise explicitly specified.

[0019] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0020] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method comprising steps (a) and (b) indicates that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0021] In this application, "above" or "below" includes the number itself. For example, "below 1" includes 1.

[0022] In this application, room temperature refers to 0~40℃, including but not limited to 10~40℃, or further to 20~30℃.

[0023] The present application will be further illustrated by the following examples, but these examples do not limit the scope of the present application.

[0024] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this application, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or instruments whose manufacturers are not specified are conventional products that can be purchased commercially. In addition to the specific methods, equipment, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description in this application, any prior art methods, equipment, and materials similar to or equivalent to those described, used, or made by the methods, equipment, and materials in the embodiments of this application may be used to implement this application.

[0025] The self-healing polyurethane composition coating structures of Examples 1-3 and Comparative Examples 1-2 are as follows: Figure 1 As shown.

[0026] Preparation Example 1 The specific steps for preparing the copper complex in this preparation example are as follows: Dissolve 5.2 g of stearic acid in 30 mL of toluene, heat to 65 °C and stir to dissolve. Then slowly add 1.5 mL of oxaloyl chloride at a rate of 0.2 mL / min, cool to 25 °C and react for 2 h. Then add 3 g of 8-hydroxyquinoline and continue stirring for 1 h. After that, wash twice with 5% sodium bicarbonate aqueous solution and deionized water, respectively. Dry the organic phase with anhydrous magnesium sulfate, then remove the solvent by rotary evaporation. Then place it in 40 mL of 1.5% copper sulfate solution, adjust the stirring speed to 300 r / min and treat for 10 min. After separation, remove the aqueous phase to obtain the copper complex.

[0027] The specific steps for preparing the aliphatic-copper complex crystal in this preparation example are as follows: Disperse 0.5g of hydrogenated castor oil and 0.1g of copper complex in 4mL of acetone preheated to 50℃ to obtain solution A; preheat anhydrous ethanol to 60℃ to obtain solution B; mix solution A and solution B at a ratio of 1:10 (v / v) and sonicate at 65℃ (pulse mode, 10s, power 300W) to obtain an emulsion, then cool to room temperature at a rate of 0.5℃ / min, let stand overnight, collect the bottom precipitate by centrifugation, and dry under vacuum at 25℃ to obtain the final product.

[0028] Preparation Example 2 The specific steps for preparing the copper complex in this preparation example are as follows: Dissolve 5.4 g of stearic acid in 35 mL of toluene, heat to 65 °C and stir to dissolve. Then slowly add 1.5 mL of oxaloyl chloride at a rate of 0.5 mL / min, cool to 25 °C and react for 2 h. Then add 3.2 g of 8-hydroxyquinoline and continue stirring for 1.5 h. After that, wash twice with 5% sodium bicarbonate aqueous solution and deionized water, respectively. Dry the organic phase with anhydrous magnesium sulfate, then remove the solvent by rotary evaporation. Then place it in 50 mL of 2% copper sulfate solution and treat with stirring at 400 r / min for 20 min. After separation, remove the aqueous phase to obtain the copper complex.

[0029] The specific steps for preparing the aliphatic-copper complex crystal in this preparation example are as follows: Disperse 0.8g of hydrogenated castor oil and 0.15g of copper complex in 5mL of acetone preheated to 50℃ to obtain solution A; preheat anhydrous ethanol to 60℃ to obtain solution B; mix solution A and solution B at a ratio of 1:12 (v / v) and sonicate at 65℃ (pulse mode, 30s, power 300W) to obtain an emulsion, then cool to room temperature at a rate of 1.0℃ / min, let stand overnight, collect the bottom precipitate by centrifugation, and dry under vacuum at 25℃ to obtain the final product.

[0030] Preparation Example 3 The only difference between this preparation example and Preparation Example 1 is that the specific steps for preparing the copper complex are as follows: Dissolve 5.5 g of stearic acid in 40 mL of toluene, heat to 70 °C and stir to dissolve. Then slowly add 1.7 mL of oxaloyl chloride at a rate of 0.5 mL / min, cool to 25 °C and react for 3 h. Then add 3.2 g of 8-hydroxyquinoline and continue stirring for 1.5 h. After that, wash three times with 5% sodium bicarbonate aqueous solution and deionized water. Dry the organic phase with anhydrous magnesium sulfate, then remove the solvent by rotary evaporation. Then place it in 50 mL of 2% copper sulfate solution and treat with stirring at 400 r / min for 20 min. After separation, remove the aqueous phase to obtain the copper complex.

[0031] The remaining steps are the same as those in Preparation Example 1.

[0032] Example 1 A. Preparation of mixed emulsion: By weight, take 50 parts of polycaprolactone diol (model: PCL210n) and isocyanate (model: Basonate) ®Mix 15 parts of HI 100 NG AP, 0.5 parts of leveling agent (model: BYK-333), 1 part of light stabilizer (model: tinuvin292), 2 parts of aliphatic-copper complex crystals, 5 parts of dimethyl ethyl ketone oxime, and 0.01 parts of dibutyltin dilaurate. Then add 20 parts of composite solvent (butyl acetate and propylene glycol methyl ether acetate (v / v) = 4:1). Mix and stir at 150 r / min for 30 min, then let stand to defoam for 10 min to obtain a mixed emulsion. B. Substrate cleaning: Place substrate 2 in ethanol and sonicate at 5KHz for 1 min, then dry for later use; C. Coating: The mixed emulsion is coated on the substrate layer 2 using a roller coating or slot coating process to form a self-healing polyurethane composition coating 1; D. Coating curing: The coated substrate 2 is placed in an environment of 50°C for 5 days to obtain a self-healing polyurethane composition cured coating.

[0033] The aliphatic-copper complex precipitate was prepared in Preparation Example 1.

[0034] Example 2 A. Preparation of mixed emulsion: By weight, take 60 parts of polycaprolactone diol (model: PCL210n) and isocyanate (model: Basonate)... ® Mix 18 parts of HI 100 NG AP, 1 part of leveling agent (model: BYK-333), 1.5 parts of light stabilizer (model: tinuvin292), 3 parts of aliphatic-copper complex crystals, 5 parts of dimethyl ethyl ketone oxime, and 0.05 parts of dibutyltin dilaurate. Then add 25 parts of composite solvent (butyl acetate and propylene glycol methyl ether acetate (v / v) = 4:1). Mix and stir at 200 r / min for 50 min, then let stand to defoam for 10 min to obtain a mixed emulsion. B. Substrate cleaning: Place substrate 2 in ethanol and sonicate at 10KHz for 2 minutes, then dry for later use; C. Coating: The mixed emulsion is coated on the substrate layer 2 using a roller coating or slot coating process to form a self-healing polyurethane composition coating 1; D. Coating curing: The coated substrate 2 is placed in an environment of 60°C for 7 days to obtain a self-healing polyurethane composition cured coating.

[0035] The aliphatic-copper complex precipitate was prepared in Preparation Example 2.

[0036] Example 3 A. Preparation of mixed emulsion: By weight, take 60 parts of polycaprolactone diol (model: PCL210n) and isocyanate (model: Basonate)... ®Mix 20 parts of HI 100 NG AP, 2 parts of leveling agent (model: BYK-333), 2 parts of light stabilizer (model: tinuvin292), 5 parts of aliphatic-copper complex crystals, 8 parts of dimethyl ethyl ketone oxime, and 0.05 parts of dibutyltin dilaurate. Then add 30 parts of composite solvent (butyl acetate and propylene glycol methyl ether acetate (v / v) = 5:1). Mix and stir at 200 r / min for 50 min, then let stand to defoam for 10 min to obtain a mixed emulsion. B. Substrate cleaning: Place substrate 2 in ethanol and sonicate at 15KHz for 1 min, then dry for later use; C. Coating: The mixed emulsion is coated on the substrate layer 2 using a roller coating or slot coating process to form a self-healing polyurethane composition coating 1; D. Coating curing: The coated substrate 2 is placed in an environment of 60°C for 7 days to obtain a self-healing polyurethane composition cured coating.

[0037] The aliphatic-copper complex precipitate was prepared in Preparation Example 3.

[0038] Comparative Example 1 The only difference between this comparative example and Example 1 is that an equal amount of pretreated hydrogenated castor oil was used instead of ester-copper complex crystals to prepare a self-healing polyurethane composition, and a coating was further obtained.

[0039] The pretreated hydrogenated castor oil is obtained by impregnating hydrogenated castor oil with a 2% copper sulfate solution and then drying it.

[0040] Comparative Example 2 The only difference between this comparative example and Example 1 is that the preparation steps of the aliphatic-copper complex crystals are as follows: Disperse 0.8g of hydrogenated castor oil in 5mL of acetone preheated to 50℃ to obtain solution A; preheat anhydrous ethanol to 60℃ to obtain solution B; mix solution A and solution B at a ratio of 1:12 (v / v), and sonicate at 65℃ (pulse mode, 30s, power 300W) to obtain an emulsion. Then, cool to room temperature at a rate of 1.0℃ / min, let stand overnight, collect the bottom precipitate by centrifugation, dry under vacuum at 25℃, and mix with 0.15g of copper complex to obtain the final product.

[0041] Performance testing 1. Coating anti-fouling performance test This experiment used an optical contact angle meter to test the liquid contact angle. The test droplet was an aqueous solution with an ash content of 0.5% by mass, and the test volume was 5 μL. The contact angles of the self-healing polyurethane composition coatings of Examples 1-3 and Comparative Examples 1-2 were obtained. The test results are as follows: Figure 2 As shown.

[0042] 2. Apparent performance test Table 1. Apparent performance test results of self-healing polyurethane composition coatings of Examples 1-3 and Comparative Examples 1-2 Examples 1-3 and Comparative Examples 1-2 are combined. Figures 1-2 It can be concluded that the antifouling performance of the coatings is enhanced after adding hydrogenated castor oil to the self-healing polyurethane composition. Among all test groups, Comparative Example 2 has the weakest antifouling performance. Further, combined with the appearance test results in Table 1, the self-healing polyurethane coating prepared using the aliphatic-copper complex crystals of the present application embodiment has improved tensile and folding resistance properties and can reduce the risk of coating cracking. Due to the lack of sufficient copper ion coordinating components, the aliphatic-copper complex crystals in Comparative Example 1 did not solve the problem of copper ion aggregation after being added to the mixed emulsion. Moreover, due to the compatibility problem between hydrogenated castor oil and polyurethane matrix, the coating is more prone to cracking, which affects the coating's aging resistance and self-healing ability. In contrast, Comparative Example 2 still suffers from compatibility problems due to the poor matching between hydrogenated castor oil and copper complex, which also reduces the coating's performance.

[0043] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a self-healing polyurethane composition, characterized in that, The following raw materials are mixed and processed to obtain the product: 50-60 parts polycaprolactone diol, 15-20 parts isocyanate, 0.5-2 parts leveling agent, 1-2 parts light stabilizer, 20-30 parts composite solvent, 2-5 parts aliphatic-copper complex crystals, 5-8 parts dimethylglyoxime, and 0.01-0.05 parts catalyst. The preparation steps of the aliphatic-copper complex crystal include the following: S01. Take hydrogenated castor oil and copper complex, mix them, add acetone, preheat and disperse to obtain solution A; S02. Take anhydrous ethanol, preheat it, and obtain solution B; S03. Mix solution A and solution B, sonicate, cool to crystallize, then centrifuge to collect the precipitate, and dry to obtain the final product; In step S01, the mass-to-volume ratio of hydrogenated castor oil, copper complex, and acetone used is (0.5-0.8)g:(0.1-0.15)g:(4-5)mL; In step S03, liquid A and liquid B are mixed at a volume ratio of 1:(10-12); The preparation steps of the copper complex include the following: Take stearic acid, disperse it, heat it and add oxaloyl chloride, then cool it down to react, then add 8-hydroxyquinoline, continue stirring to react, then rotary evaporate it, transfer the product to the impregnation solution, stir it, and finally separate the aqueous phase to obtain the product; The impregnation solution is a copper sulfate solution with a mass concentration of 1.5%-2%.

2. The method for preparing a self-healing polyurethane composition according to claim 1, characterized in that, The mass-to-volume ratio of stearic acid, oxaloyl chloride and 8-hydroxyquinoline used is (5.2-5.5) g:(1.5-1.7) mL:(3-3.2) g.

3. The method for preparing a self-healing polyurethane composition according to claim 1, characterized in that, In step S03, the ultrasound is set to pulse mode, 10-30s, and the power is 300W; the cooling crystallization is set to a rate program of 0.5-1.0℃ / min to cool to room temperature, and then left overnight.

4. The method for preparing a self-healing polyurethane composition according to claim 1, characterized in that, The composite solvent is obtained by mixing butyl acetate and propylene glycol methyl ether acetate in a volume ratio of (4-5):

1.

5. A self-healing polyurethane composition, characterized in that, It is prepared by any one of the preparation methods described in claims 1-4.

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