Single-component polyurethane road pit slot rapid repairing material and preparation method thereof

Abstract

The invention belongs to the technical field of polyurethane materials, and particularly relates to a single-component polyurethane road pit slot rapid repair material and a preparation method thereof. The repairing material is prepared from the following raw materials in parts by weight: 48 to 50 parts of polyurethane prepolymer, 15 to 20 parts of curing agent, 20 to 25 parts of filler, 1 to 5 parts of modifier, 1 to 5 parts of multi-layer composite capsule, 0.5 to 2 parts of dispersing agent, 2 to 4 parts of plasticizer, 1 to 2 parts of ultraviolet light absorber and 0.1 to 0.5 part of organic tin catalyst. The prepared multi-layer composite capsule has the characteristics of outer layer brittle rupture and inner layer humidity response, has the effects of low-temperature rupture capacity, humidity responsiveness and heat conduction and humidity control, and is matched with the graphene oxide modified polyurethane prepolymer, so that not only can the heat conduction capacity of a polyurethane system be improved, but also the heat conduction performance of the polyurethane system can be improved. And the curing performance, the wear resistance and the crack resistance of the existing polyurethane repairing material in low-temperature and humid environments can be effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyurethane materials, and particularly relates to a one-component polyurethane rapid repair material for road potholes and a preparation method thereof. Background Art

[0002] The rapid road pothole repair material is a material used to quickly repair potholes and cracks on the road surface. The main types include polymer-modified asphalt, cement-based materials, polyurethane resins, epoxy resins, and adhesive-type materials, etc. However, the current repair materials have problems such as long curing time, poor adhesion performance, insufficient durability, difficult construction operation, poor environmental protection, and high cost. In particular, the polyurethane repair materials have prominent problems of poor curing performance, insufficient wear resistance and crack resistance in low-temperature and humid environments. This is mainly due to factors such as the kinetic limitations of the curing reaction, the adverse effects of humidity on the reaction, insufficient crosslinking degree, and uneven stress distribution. These problems directly affect the repair effect and service life of the polyurethane repair materials. Therefore, it is necessary to develop new rapid repair materials to solve the current technical problems.

[0003] For example, Chinese Patent CN113336472B discloses an epoxy-modified polyurethane road repair material and a preparation method thereof, including component A, component B, and component C. The raw material ratios in each component are in parts by weight. Among them, component A includes 100 parts of polyether polyol, 20 - 60 parts of isocyanate, 10 - 50 parts of epoxy resin, and 5 - 15 parts of plasticizer; component B includes 5 - 25 parts of amine curing chain extender, 2 - 30 parts of tertiary amine-based polyether diol, 0.5 - 3 parts of accelerator, 1 - 5 parts of thixotropic agent, and 5 - 20 parts of diluent; component C is aggregate; and the weight ratio of component A to component B is 3 - 10:1, and the weight ratio of the sum of component A and component B to component C is 1:3 - 10. This epoxy-modified polyurethane road repair material can be used for repairing damaged potholes on the road and has good toughness and mechanical properties. However, this epoxy-modified polyurethane road repair material has a low repair efficiency in low-temperature or humid environments; and cracking, peeling and other phenomena are likely to occur in extremely low-temperature environments. Therefore, the present invention provides a one-component polyurethane rapid repair material for road potholes and a preparation method thereof in order to solve the above technical problems. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a one-component polyurethane rapid repair material for road potholes and its preparation method. The multi-layer composite capsules prepared by the present invention have the characteristics of brittle rupture of the outer layer and humidity response of the inner layer. Using them as raw materials for polyurethane rapid repair materials for road potholes can endow the repair materials with low-temperature rupture ability, humidity response, and the effects of heat conduction and humidity control. At the same time, combined with graphene oxide-modified polyurethane prepolymer, it can not only improve the heat conduction ability of the system, but also effectively improve the curing performance, wear resistance and crack resistance of existing polyurethane repair materials in low-temperature and humid environments.

[0005] A one-component polyurethane rapid repair material for road potholes, comprising the following raw materials by weight: 48-50 parts of polyurethane prepolymer, 15-20 parts of curing agent, 20-25 parts of filler, 1-5 parts of modifier, 1-5 parts of multi-layer composite capsules, 0.5-2 parts of dispersant, 2-4 parts of plasticizer, 1-2 parts of ultraviolet absorber and 0.1-0.5 parts of organotin catalyst.

[0006] The multi-layer composite capsules provided by the present invention with the characteristics of brittle rupture of the outer layer and humidity response of the inner layer can play a role in increasing the temperature of the polyurethane system and reducing its humidity in the one-component polyurethane rapid repair material for road potholes, effectively solving the problem of poor curing performance of polyurethane repair materials in low-temperature and humid environments.

[0007] Furthermore, the multi-layer composite capsules include a core substance, an inner shell and an outer shell;

[0008] The core substance is calcium chloride, and its mass accounts for 80% of the multi-layer composite capsules;

[0009] The inner shell is a starch-polyvinyl alcohol composite, and its mass accounts for 10-15% of the multi-layer composite capsules;

[0010] The outer shell is a modified polyacrylate resin, and its mass accounts for 5-10% of the multi-layer composite capsules.

[0011] In the present invention, calcium chloride is used as the core material of the multi-layer composite capsule. The hygroscopicity and exothermic property of calcium chloride ensure that the multi-layer composite capsule can quickly absorb moisture and increase the system temperature under humid conditions, which helps the polyurethane to cure rapidly in a low-temperature environment. Then, a starch-polyvinyl alcohol composite is used as the inner shell of the multi-layer composite capsule. Starch and polyvinyl alcohol in it have good moisture absorption properties, and can expand especially in a humid environment, enhancing the response speed of the inner layer to humidity. Moreover, the combination of the hydrophilicity of starch and the flexibility of polyvinyl alcohol enables the inner shell to have a higher expansion rate and can accelerate the rupture of the outer shell. At the same time, the present invention increases the brittleness of polyacrylate at low temperatures through modification treatment to ensure its embrittlement and rupture performance in a low-temperature environment, so that it is easily ruptured due to mechanical stimulation in a low-temperature environment, that is, the multi-layer composite capsule can be ruptured under mild pressure or mechanical stirring during road repair, meeting the low-temperature rupture requirement, and finally achieving the effects of increasing the temperature of the polyurethane system and reducing humidity, and helping the polyurethane repair material to cure rapidly in a low-temperature and humid environment.

[0012] Further, the preparation of the inner shell includes: dissolving starch and polyvinyl alcohol in water, stirring and heating to 80 - 90 °C, continuously stirring for 1.5 - 2.5 h until a uniform composite solution is formed, then cooling the solution to room temperature, adding formic acid, and stirring evenly to obtain a starch-polyvinyl alcohol composite solution;

[0013] Among them, the mass percentage of the starch and polyvinyl alcohol is 8 - 13 wt%.

[0014] The mass percentage of the formic acid is 0.8 - 1.2 wt%.

[0015] The inner shell starch-polyvinyl alcohol material prepared by the present invention through the above method will expand when the humidity increases, which can accelerate the rupture of the outer shell. This property ensures that the multi-layer composite capsule can quickly release calcium chloride in a humid environment. Moreover, the added formic acid has the effect of accelerating the hydrolysis of starch-polyvinyl alcohol in a high-humidity environment and making the outer shell fragile.

[0016] Further, the mass ratio of the starch to the polyvinyl alcohol is 2:1.

[0017] Further, the preparation of the outer shell includes: dissolving a polyacrylate resin in a solvent to obtain a resin solution, then adding an aminosilane to the resin solution and stirring, adding an acidic catalyst, stirring evenly, then raising the temperature to 60 - 80 °C, reacting for 3 - 5 h, and after the reaction is completed, cooling to room temperature to obtain a modified polyacrylate resin;

[0018] Among them, the dosage ratio of the polyacrylate resin to the solvent is 1 g:(2 - 5) mL;

[0019] The dosage of the amino silane is 1-2% of the mass of the polyacrylate resin;

[0020] The dosage of the acidic catalyst is 0.5-1% of the mass of the polyacrylate resin.

[0021] By using the above method to modify the polyacrylate resin with amino silane, the present invention ensures the low-temperature embrittlement characteristics of the shell layer, and enhances the hardness and fragility of the outer shell of the multi-layer composite capsule. The modified polyacrylate outer layer will become fragile at low temperatures (such as -10°C to 20°C), and will break when encountering mechanical pressure or slight shear force during road construction, and can quickly release the inner layer material.

[0022] Furthermore, the solvent is ethanol or isopropanol; the amino silane is 3-aminopropyltriethoxysilane or 3-aminopropyltrimethoxysilane; the acidic catalyst is acetic acid or sulfuric acid.

[0023] Furthermore, the preparation of the multi-layer composite capsule includes:

[0024] Step (1): Dry calcium chloride to constant weight, control the drying temperature at 90-100°C, and the time is 2-4h. After drying, grind it to obtain the core material calcium chloride powder;

[0025] Step (2): Put the core material calcium chloride powder into a spray dryer, then add a starch-polyvinyl alcohol composite solution to coat the core material, and then dry the particles. The drying temperature is 55-60°C, and the inner layer coated particles are formed after drying;

[0026] Step (3): Then coat the modified polyacrylate resin on the inner layer coated particles. The thickness of the modified polyacrylate resin layer is 1-5 microns, and the coated particles are dried. The drying temperature is 35-45°C to obtain the multi-layer composite capsule.

[0027] The outer shell of the multi-layer composite capsule of the present invention is endowed with the ability to rupture at low temperature. Due to the brittleness of the modified polyacrylate, the multi-layer composite capsule can rupture under mild pressure during road repair, meeting the low-temperature rupture requirement; while the inner shell of the multi-layer composite capsule of the present invention is endowed with humidity responsiveness. In a humid environment, the inner layer material will absorb moisture and expand, making the outer layer easier to break; and the core material of the multi-layer composite capsule of the present invention is endowed with heat conduction and humidity control capabilities. The strong hygroscopicity and exothermic properties of calcium chloride can significantly improve the curing speed and efficiency of polyurethane resin in low-temperature and humid environments.

[0028] Furthermore, the modifier is graphene oxide.

[0029] Further, the curing agent is triethylenediamine; the filler is quartz sand with a particle size of 100 - 300 microns; the dispersant is polyvinyl alcohol; the plasticizer is diisononyl phthalate or didecyl sebacate; the ultraviolet absorber is UV-531; the organotin catalyst is tributyl(1-ethoxyvinyl)tin.

[0030] Moreover, the present invention also provides a preparation method of the one-component polyurethane rapid road pothole repair material as described above, comprising the following steps:

[0031] Step 1:

[0032] Prepare the capsule: First, put calcium chloride into a spray dryer, and then coat calcium chloride with a starch - polyvinyl alcohol composite solution and dry it; then coat it with a modified polyacrylate resin and dry it to obtain a multi-layer composite capsule;

[0033] Prepare the graphene dispersion: Add graphene oxide to deionized water, add polyvinyl alcohol, and then perform ultrasonic treatment for 30 - 60 min to obtain the graphene dispersion; the mass percentage of the graphene oxide is 2 - 4 wt%; the mass percentage of the polyvinyl alcohol is 1 - 1.5 wt%;

[0034] Step 2:

[0035] Pour the polyurethane prepolymer into a reaction kettle, heat it to 55 - 65 °C, and stir evenly; then add the graphene dispersion prepared in Step 1 to the polyurethane prepolymer, and continue to stir for 20 - 30 min; then add the filler, plasticizer, ultraviolet absorber, dispersant, and organotin catalyst, and continue to stir for 20 - 30 min to obtain a mixture; the stirring speed is 500 - 800 revolutions / min;

[0036] Step 3:

[0037] Cool the temperature of the mixture obtained in Step 2 to room temperature, then slowly add the multi-layer composite capsule prepared in Step 1 thereto, stir at a stirring speed of 50 - 100 revolutions / min for 3 - 5 min, and then add the curing agent and stir evenly to obtain the one-component polyurethane rapid road pothole repair material. Usually, the curing agent is added to the system during construction and repair applications, which can extend the operable time of the material and ensure good fluidity and appropriate curing time during construction.

[0038] The present invention uses graphene oxide to modify polyurethane prepolymer, significantly improving the thermal conductivity of the system. Secondly, during the road repair process, reactions such as the rupture of multi-layer composite capsules and the curing of polyurethane are accompanied by heat release. After the material is modified by graphene in the present invention, it can effectively promote the rapid distribution of heat inside the material, thereby increasing the overall temperature of the curing reaction, helping to quickly conduct the heat generated during the repair curing process to all parts of the material, avoiding the problems of excessive or too low local temperature, and then improving the uniformity of curing. This is particularly important for the curing process in low-temperature environments, which can significantly accelerate the reaction rate and ensure that the material can be effectively cured in low-temperature environments. Moreover, the dispersibility and toughness of graphene can also alleviate the sensitivity of polyurethane to moisture and help it maintain stable curing performance in humid environments. Furthermore, the modification of graphene can effectively enhance the abrasion resistance of polyurethane, helping to form a tough and excellent crack-resistant network structure after polyurethane curing, which can better resist external impacts and stress concentration, enabling the repaired material to maintain good performance on roads with heavy traffic and severe wear.

[0039] Compared with the prior art, a one-component polyurethane rapid road pothole repair material and its preparation method provided by the present invention have the following advantages:

[0040] (1) The multi-layer composite capsules prepared in the present invention have the characteristics of brittle rupture of the outer layer and humidity response of the inner layer, which have a significant impact on the curing of the polyurethane system in low-temperature and humid environments. The outer shell of the multi-layer composite capsules in the present invention is composed of modified polyacrylate resin, which can brittlely rupture under low-temperature conditions, ensuring that when the one-component polyurethane rapid road pothole repair material is applied or subjected to external forces, the outer layer can quickly rupture. And the inner shell starch-polyvinyl alcohol composite of the multi-layer composite capsules in the present invention can adjust the release of calcium chloride when the humidity changes. This humidity response characteristic ensures that the capsules can effectively release moisture in humid environments while controlling the release rate of calcium chloride, avoiding uneven curing caused by too fast release. This protective effect ensures that calcium chloride is released in an appropriate amount at an appropriate time, thus supporting the reaction of polyurethane. This inner and outer layer design mechanism of the multi-layer composite capsules prepared in the present invention ensures that in practical applications, the repair material can quickly adapt to changing environmental conditions and greatly improve the curing efficiency.

[0041] (2) The present invention adds graphene dispersion to polyurethane prepolymer, which can not only significantly improve the thermal conductivity of the material, but also help to overcome the problems of poor curing performance, insufficient abrasion resistance and crack resistance of polyurethane repair materials in low-temperature and humid environments. By optimizing thermal management, improving the curing reaction rate, and enhancing the mechanical properties of the material, the introduction of graphene expands new possibilities for the application of polyurethane materials. Especially in practical applications in the field of road repair and other fields, it can significantly improve the comprehensive performance and service life of the material. Detailed implementation manners

[0042] The present invention will be further described below through the description of specific implementation manners. However, this is not a limitation to the present invention. Those skilled in the art can make various modifications or improvements according to the basic idea of the present invention. As long as they do not depart from the basic idea of the present invention, they are all within the protection scope of the present invention.

[0043] In the following examples and comparative examples, the methods used, unless otherwise specified, are all prior arts; the reagents not specially described are conventional reagents, which can be purchased from conventional reagent production and sales companies. The information of some raw material manufacturers or CAS numbers, etc. is as follows:

[0044] Polyurethane prepolymer, purchased from Zibo Qishang Network Technology Co., Ltd.;

[0045] Polyvinyl alcohol, purchased from Jianshi Mineral Powder Factory, Lingshou County;

[0046] Polyacrylate resin, purchased from Jinan Feiyue Chemical Co., Ltd.;

[0047] 3-Aminopropyltriethoxysilane, CAS number is 919-30-2;

[0048] 3-Aminopropyltrimethoxysilane, CAS number is 13822-56-5;

[0049] Graphene oxide, purchased from Dinghong Metal Materials Co., Ltd., Nangong City, model number FQ-28;

[0050] Triethylenediamine, CAS number is 280-57-9;

[0051] Diisononyl phthalate, CAS number is 28553-12-0;

[0052] Didecyl sebacate, CAS number is 2432-89-5;

[0053] Tributyl(1-ethoxyvinyl)tin, CAS number is 97674-02-7.

[0054] Example 1

[0055] Prepare a one-component polyurethane rapid repair material for road potholes, including the following steps:

[0056] Step 1:

[0057] Preparation of capsules: First, put the core material calcium chloride into a spray dryer, then coat the calcium chloride with a starch-polyvinyl alcohol composite solution and dry it to obtain the inner shell; then coat the outer shell with a modified polyacrylate resin and dry it to obtain a multi-layer composite capsule; among them, the mass of the core material calcium chloride accounts for 80% of the multi-layer composite capsule; the mass of the inner shell starch-polyvinyl alcohol composite accounts for 10% of the multi-layer composite capsule; the mass of the outer shell modified polyacrylate resin accounts for 10% of the multi-layer composite capsule.

[0058] The specific operations are as follows:

[0059] Step (1): Dry 200 g of calcium chloride to a constant weight, control the drying temperature at 90 °C for 4 h, and after drying, grind it to a particle size of 50 - 100 microns to obtain the core material calcium chloride powder;

[0060] The preparation method of the inner shell starch-polyvinyl alcohol composite solution is as follows: Dissolve 20 g of starch and 10 g of polyvinyl alcohol in water, stir and heat to 80 °C, continuously stir for 2.5 h until a uniform composite solution is formed, cool to room temperature, add formic acid, and stir evenly to obtain the starch-polyvinyl alcohol composite solution; among them, the mass percentage of the starch and polyvinyl alcohol is 8 wt%; the mass percentage of the formic acid is 0.8 wt%;

[0061] The preparation method of the outer shell is as follows: Dissolve 20 g of polyacrylate resin in 40 mL of ethanol solvent to obtain a resin solution, then add the amino silane 3-aminopropyltriethoxysilane to the resin solution and stir, then add the acidic catalyst acetic acid, stir evenly, then raise the temperature to 60 °C and react for 5 h. After the reaction, cool to room temperature to obtain the modified polyacrylate resin; among them, the dosage of the amino silane is 1% of the mass of the polyacrylate resin; the dosage of the acidic catalyst is 0.5% of the mass of the polyacrylate resin.

[0062] Step (2): Put the core material calcium chloride powder into a spray dryer, then add the starch-polyvinyl alcohol composite solution to coat the core material, and then dry the particles. The drying temperature is 55 °C, and the inner-coated particles are formed after drying;

[0063] Step (3): Coat the inner-coated particles with the modified polyacrylate resin, the thickness of the modified polyacrylate resin layer is 2 microns, and then dry the coated particles at a drying temperature of 35 °C to obtain a multi-layer composite capsule.

[0064] Preparation of the modifier graphene dispersion: Add 10 g of graphene oxide to deionized water, add polyvinyl alcohol, and then use an ultrasonic cleaner for ultrasonic treatment for 30 min; the mass percentage of the graphene oxide is 2 wt%; the mass percentage of the polyvinyl alcohol is 1 wt%;

[0065] Step 2:

[0066] Pour 480 g of polyurethane prepolymer into the reaction kettle, heat it to 55 °C, and stir evenly; then add the modified graphene dispersant solution prepared in Step 1 into the polyurethane prepolymer, and continue to stir for 20 min; then add 200 g of filler quartz sand (the filler particle size is 100 - 300 microns), 20 g of plasticizer diisononyl phthalate, 10 parts of ultraviolet absorber UV - 531, 5 g of dispersant polyvinyl alcohol, and 1 g of organotin catalyst tributyl(1 - ethoxyvinyl)tin, and continue to stir for 20 min to obtain a mixture; the stirring speed is 500 revolutions / min;

[0067] Step 3:

[0068] Lower the temperature of the mixture obtained in Step 2 to room temperature, then slowly add 10 g of the multi - layer composite capsule prepared in Step 1 thereto, and stir at a stirring speed of 50 revolutions / min for 5 min, then add 150 g of curing agent triethylenediamine, and stir evenly to obtain a one - component polyurethane rapid repair material for road potholes.

[0069] Example 2

[0070] Prepare a one - component polyurethane rapid repair material for road potholes, including the following steps:

[0071] Step 1:

[0072] Prepare the capsule: First, put the core substance calcium chloride into the spray dryer, and then coat the calcium chloride with a starch - polyvinyl alcohol composite solution and dry it to obtain the inner shell; then coat the outer shell with a modified polyacrylate resin and dry it to obtain a multi - layer composite capsule; among them, the mass of the core substance calcium chloride accounts for 80% of the multi - layer composite capsule; the mass of the inner shell starch - polyvinyl alcohol composite accounts for 15% of the multi - layer composite capsule; the mass of the outer shell modified polyacrylate resin accounts for 5% of the multi - layer composite capsule.

[0073] The specific operation is as follows:

[0074] Step (1) Dry 200 g of calcium chloride to constant weight, control the drying temperature at 100 °C, and the time is 2 h. After drying, grind it, and the particle size is 50 - 100 microns to obtain the core substance calcium chloride powder;

[0075] The preparation method of the inner shell starch-polyvinyl alcohol composite solution is as follows: Dissolve 20 g of starch and 10 g of polyvinyl alcohol in water, stir and heat up to 90 °C, continuously stir for 2.5 h until a uniform composite solution is formed, cool to room temperature, add formic acid, and stir evenly to obtain the starch-polyvinyl alcohol composite solution; wherein, the mass percentage of the starch and polyvinyl alcohol is 13 wt%; the mass percentage of the formic acid is 1.2 wt%.

[0076] The preparation method of the outer shell is as follows: Dissolve 20 g of polyacrylate resin in 100 mL of isopropanol solvent to obtain a resin solution, then add 3-aminopropyltrimethoxysilane of amino silane to the resin solution and stir, then add acidic catalyst sulfuric acid, stir evenly, then raise the temperature to 80 °C, react for 3 h, after the reaction is completed, cool to room temperature to obtain the modified polyacrylate resin; wherein, the dosage of the amino silane is 2% of the mass of the polyacrylate resin; the dosage of the acidic catalyst is 1% of the mass of the polyacrylate resin.

[0077] In step (2), put the core material calcium chloride powder into a spray dryer, then add the starch-polyvinyl alcohol composite solution to carry out core material coating, and then dry the particles. The drying temperature is 60 °C, and inner-layer coated particles are formed after drying.

[0078] In step (3), then coat the modified polyacrylate resin on the inner-layer coated particles. The thickness of the modified polyacrylate resin layer is 5 microns, and then dry the coated particles. The drying temperature is 45 °C to obtain multi-layer composite capsules.

[0079] Prepare the modifier graphene dispersion liquid: Add 50 g of graphene oxide to deionized water, add polyvinyl alcohol, and then use an ultrasonic cleaner to carry out ultrasonic treatment for 60 min; the mass percentage of the graphene oxide is 4 wt%; the mass percentage of the polyvinyl alcohol is 1.5 wt%.

[0080] Step 2:

[0081] Pour 500 g of polyurethane prepolymer into a reaction kettle, heat to 65 °C, and stir evenly; then add the modifier graphene dispersion liquid prepared in step 1 to the polyurethane prepolymer, and continue to stir for 30 min; then add 250 g of filler quartz sand (the filler particle size is 100 - 300 microns), 40 g of plasticizer dioctyl sebacate, 20 g of ultraviolet absorber UV-531, 20 g of dispersant polyvinyl alcohol, and 5 g of organotin catalyst tributyl(1-ethoxyvinyl)tin, and continue to stir for 30 min to obtain a mixture; wherein the stirring speed is 800 revolutions / min.

[0082] Step 3:

[0083] Cool the temperature of the mixture obtained in Step 2 to room temperature, then slowly add 50 g of the multi-layer composite capsules prepared in Step 1 thereto, stir at a stirring speed of 100 revolutions per minute for 3 minutes, then add 200 g of the curing agent triethylenediamine, and stir evenly to obtain a one-component polyurethane rapid repair material for road potholes.

[0084] Example 3

[0085] Prepare a one-component polyurethane rapid repair material for road potholes, including the following steps:

[0086] Step 1:

[0087] Prepare capsules: First, put the core material calcium chloride into a spray dryer, and then coat the calcium chloride with a starch-polyvinyl alcohol composite solution and dry it to obtain an inner shell; then coat the outer shell with a modified polyacrylate resin and dry it to obtain a multi-layer composite capsule; wherein, the mass of the core material calcium chloride accounts for 80% of the multi-layer composite capsule; the mass of the inner shell starch-polyvinyl alcohol composite accounts for 10% of the multi-layer composite capsule; the mass of the outer shell modified polyacrylate resin accounts for 10% of the multi-layer composite capsule.

[0088] The specific operations are as follows:

[0089] Step (1) Dry 200 g of calcium chloride to constant weight, control the drying temperature at 100 °C for 3 h, grind it after drying is completed, and the particle size is 50-100 microns to obtain calcium chloride powder as the core material;

[0090] The preparation method of the inner shell starch-polyvinyl alcohol composite solution is: dissolve 20 g of starch and 10 g of polyvinyl alcohol in water, stir and heat up to 85 °C, continuously stir for 2 h until a uniform composite solution is formed, cool to room temperature, add formic acid, and stir evenly to obtain a starch-polyvinyl alcohol composite solution; wherein, the mass percentages of the starch and polyvinyl alcohol are 10 wt%; the mass percentage of the formic acid is 1.0 wt%;

[0091] The preparation method of the outer shell is: dissolve 20 g of polyacrylate resin in 60 mL of ethanol solvent to obtain a resin solution, then add the amino silane 3-aminopropyltriethoxysilane to the resin solution and stir, then add the acidic catalyst acetic acid, stir evenly, then raise the temperature to 70 °C, react for 4 h, and after the reaction is completed, cool to room temperature to obtain a modified polyacrylate resin; wherein, the dosage of the amino silane is 1.5% of the mass of the polyacrylate resin; the dosage of the acidic catalyst is 1% of the mass of the polyacrylate resin.

[0092] Step (2): Put the core material, calcium chloride powder, into a spray dryer, then add the starch-polyvinyl alcohol composite solution to coat the core material, and then dry the particles. The drying temperature is 60 °C, and the inner-layer coated particles are formed after drying.

[0093] Step (3): Then coat the modified polyacrylate resin on the inner-layer coated particles. The thickness of the modified polyacrylate resin layer is 4 μm, and then dry the coated particles. The drying temperature is 40 °C to obtain the multi-layer composite capsules.

[0094] Prepare the modifier graphene dispersion: Add 30 g of graphene oxide to deionized water, add polyvinyl alcohol, and then use an ultrasonic cleaner for ultrasonic treatment for 40 min; the mass percentage of the graphene oxide is 3 wt%; the mass percentage of the polyvinyl alcohol is 1.2 wt%.

[0095] Step 2:

[0096] Pour 500 g of polyurethane prepolymer into a reaction kettle, heat it to 55 °C and stir evenly; then add the modifier graphene dispersion prepared in Step 1 to the polyurethane prepolymer and continue stirring for 30 min; then add 230 g of filler quartz sand (the particle size of the filler is 100 - 300 μm), 30 g of plasticizer dioctyl sebacate, 10 g of ultraviolet absorber UV-531, 10 g of dispersant polyvinyl alcohol, and 3 g of organotin catalyst tributyl(1-ethoxyvinyl)tin, and continue stirring for 20 - 30 min to obtain a mixture; the stirring speed is 600 revolutions per minute.

[0097] Step 3:

[0098] Lower the temperature of the mixture obtained in Step 2 to room temperature, then slowly add 30 g of the multi-layer composite capsules prepared in Step 1 thereto, stir at a stirring speed of 50 revolutions per minute for 5 min, and then add 150 g of curing agent triethylenediamine and stir evenly to obtain the one-component polyurethane rapid repair material for road potholes.

[0099] Comparative Example 1

[0100] The difference from Example 3 is that the multi-layer composite capsules are composed of a core material and an inner shell, and do not include an outer shell. Other steps and preparation processes are the same as those in Example 3.

[0101] Comparative Example 2

[0102] The difference from Example 3 is that the multi-layer composite capsules are composed of a core material and an outer shell, and do not include an inner shell; other steps and preparation processes are the same as those in Example 3.

[0103] Comparative Example 3

[0104] The difference from Example 3 is that the outer shell of the multi-layer composite capsule is polyacrylate resin without modification treatment, and other steps and preparation processes are the same as those in Example 3.

[0105] Comparative Example 4

[0106] The difference from Example 3 is that formic acid was not added during the preparation of the inner shell of the multi-layer composite capsule, and other steps and preparation processes are the same as those in Example 3.

[0107] Comparative Example 5

[0108] The difference from Example 3 is that the graphene dispersion as a modifier was not added in Step 2, and other steps and preparation processes are the same as those in Example 3.

[0109] Test Example: Performance Test

[0110] 1. Test materials: The one-component polyurethane rapid road pothole repair materials prepared in the examples and comparative examples of the present invention.

[0111] 2. Test methods:

[0112] (1) Temperature test:

[0113] Experimental group: The one-component polyurethane rapid road pothole repair materials prepared in the examples and comparative examples of the present invention;

[0114] Control group: The one-component polyurethane rapid road pothole repair materials prepared according to the method of Example 3, with the difference that the multi-layer composite capsule was not added.

[0115] Under the conditions of a temperature of 10°C and a humidity of 80% and a temperature of 5°C and a humidity of 80%, the initial curing temperature and the highest temperature during the curing process of the experimental group and the control group were monitored with a temperature sensor respectively, and the temperature difference was recorded. The test results are shown in Table 1 and Table 2.

[0116] Table 1 Temperature difference test result table of the examples and the control group of the present invention

[0117] Group Example 1 Example 2 Example 3 Control group Temperature difference / °C at 10 °C and 80% humidity 23 25 24 7 Temperature difference / °C at 5 °C and 80% humidity 14 16 15 2

[0118] Table 2 Temperature difference test result table of the comparative examples of the present invention

[0119] Group Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Temperature difference / °C at 10 °C and 80% humidity 17 21 18 16 15 Temperature difference / °C at 5 °C and 80% humidity 10 9 10 8 7

[0120] As can be seen from the above test results, the single-component polyurethane road pothole rapid repair material obtained in the embodiments of the present invention can significantly increase the system temperature in low-temperature and humid environments. At the same time, from the test results of each comparative group, it can be concluded that the lack of specific components will cause the overall effect to decline, and the design characteristics of the capsules have a significant impact on the functions of increasing temperature and controlling humidity. This indicates that the complete multi-layer composite capsule structure combined with the graphene oxide modification treatment is crucial for improving the curing performance of the polyurethane repair material.

[0121] The single-component polyurethane road pothole rapid repair material obtained in the embodiments of the present invention has a complete multi-layer composite capsule structure, which has the characteristics of brittle rupture of the outer layer and humidity response of the inner layer, enabling the effective release of calcium chloride. At the same time, with the graphene oxide modification treatment, the curing temperature can be significantly increased. In Comparative Example 1, the lack of the outer shell leads to a decrease in the brittle rupture ability. Although the inner layer still has a certain release function, this makes it difficult for the capsule to be stably stored in a humid environment, so the temperature difference value is significantly reduced; in Comparative Example 2, the lack of the inner shell, although a certain amount of heat can still be released through the outer layer, there is no humidity response, and the release of calcium chloride cannot be adjusted according to the environmental humidity change, and calcium chloride may be released too fast or too slow, resulting in an unstable increase in the curing temperature and a significant reduction in the curing effect; due to the unmodified outer layer of the multi-layer composite capsule in Comparative Example 3, although it has a release ability, its brittleness is insufficient, so it is also affected; in Comparative Example 4, due to the lack of formic acid, the hydrolysis rate of the inner layer slows down, resulting in too high stability of the outer layer and insufficient ability to release calcium chloride, so the temperature difference is significantly reduced, leading to a decrease in the curing efficiency; in Comparative Example 5, the lack of the modifier graphene dispersion liquid leads to a decrease in the heat conduction ability, resulting in insufficient temperature increase during the curing process.

[0122] (2) According to the national standard "Standard Test Methods for Physical and Mechanical Properties of Concrete" (GB / T 50081-2019), the compressive strength and flexural strength (MPa) of the single-component polyurethane road pothole rapid repair material were respectively tested after curing for 2 h and 8 h under the conditions of a temperature of 10 °C and a humidity of 80% and a temperature of 5 °C and a humidity of 80%. The test results are shown in Table 3.

[0123] Table 3 Performance test results

[0124]

[0125] As shown in the above table, the test results of the compressive strength and flexural strength of the single-component polyurethane rapid pothole repair material obtained in the embodiments of the present invention are all good, while the various properties of each comparative example are affected to varying degrees; this shows that the key role of the complete multi-layer composite capsule structure in the curing performance cannot be ignored, and the missing part will directly affect the curing effect of the material under different environmental conditions, thereby affecting its compressive and flexural strengths. The design of these comparative examples highlights the importance of each component in the material formulation, especially the application requirements in extreme environments.

[0126] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A one-component polyurethane rapid repair material for road potholes, characterized in that, It includes the following raw materials in parts by weight: 48 - 50 parts of polyurethane prepolymer, 15 - 20 parts of curing agent, 20 - 25 parts of filler, 1 - 5 parts of modifier, 1 - 5 parts of multi - layer composite capsule, 0.5 - 2 parts of dispersant, 2 - 4 parts of plasticizer, 1 - 2 parts of ultraviolet absorber, and 0.1 - 0.5 parts of organotin catalyst.

2. The one-component polyurethane rapid repair material for road potholes according to claim 1, characterized in that, The multi - layer composite capsule includes a core substance, an inner shell, and an outer shell; The core substance is calcium chloride, and its mass accounts for 80% of the multi - layer composite capsule; The inner shell is a starch - polyvinyl alcohol composite, and its mass accounts for 10 - 15% of the multi - layer composite capsule; The outer shell is a modified polyacrylate resin, and its mass accounts for 5 - 10% of the multi - layer composite capsule.

3. The one-component polyurethane rapid road pothole repair material according to claim 2, characterized in that The preparation of the inner shell includes: dissolving starch and polyvinyl alcohol in water, stirring and heating to 80 - 90 °C, continuously stirring for 1.5 - 2.5 h until a uniform composite solution is formed, cooling to room temperature, adding formic acid, and stirring evenly to obtain a starch - polyvinyl alcohol composite solution; Among them, the mass percentage of the starch and polyvinyl alcohol is 8 - 13 wt%; The mass percentage of the formic acid is 0.8 - 1.2 wt%.

4. The one-component polyurethane rapid repair material for road potholes according to claim 3, wherein The mass ratio of the starch to the polyvinyl alcohol is 2:

1.

5. The one-component polyurethane rapid pothole repair material according to claim 2, characterized in that, The preparation of the outer shell includes: dissolving polyacrylate resin in a solvent to obtain a resin solution, then adding aminosilane to the resin solution and stirring, then adding an acidic catalyst and stirring evenly, then raising the temperature to 60 - 80 °C, reacting for 3 - 5 h, after the reaction is completed, cooling to room temperature to obtain a modified polyacrylate resin; Among them, the dosage ratio of the polyacrylate resin to the solvent is 1 g:(2 - 5) mL; The dosage of the aminosilane is 1 - 2% of the mass of the polyacrylate resin; The dosage of the acidic catalyst is 0.5 - 1% of the mass of the polyacrylate resin.

6. The one-component polyurethane rapid road pothole repair material according to claim 5, characterized in that The solvent is ethanol or isopropanol; the aminosilane is 3 - aminopropyltriethoxysilane or 3 - aminopropyltrimethoxysilane; the acidic catalyst is acetic acid or sulfuric acid.

7. The one-component polyurethane rapid road pothole repair material according to claim 2, characterized in that The preparation of the multi - layer composite capsule includes: Step (1): drying calcium chloride to constant weight, controlling the drying temperature at 90 - 100 °C for 2 - 4 h, and grinding after drying to obtain calcium chloride powder as the core substance; Step (2): putting the calcium chloride powder as the core substance into a spray dryer, then adding the starch - polyvinyl alcohol composite solution for coating the core substance, and then drying the particles, with the drying temperature being 55 - 60 °C, and forming inner - coated particles after drying; Step (3): further coating the modified polyacrylate resin on the inner - coated particles, the thickness of the modified polyacrylate resin layer is 1 - 5 microns, and drying the coated particles, with the drying temperature being 35 - 45 °C to obtain a multi - layer composite capsule.

8. The one-component polyurethane rapid repair material for road potholes according to claim 1, wherein, The modifier is graphene oxide.

9. The one-component polyurethane rapid repair material for road potholes according to claim 1, characterized in that, The curing agent is triethylenediamine; the filler is quartz sand, and the filler particle size is 100 - 300 microns; the dispersant is polyvinyl alcohol; the plasticizer is diisononyl phthalate or diisodecyl sebacate; the ultraviolet absorber is UV - 531; the organotin catalyst is tributyl(1 - ethoxyvinyl)tin.

10. The preparation method of the one-component polyurethane rapid repair material for road potholes according to any one of claims 1-8, characterized in that, It includes the following steps: Step 1: Prepare the capsules: First, put calcium chloride into a spray dryer, and then coat the calcium chloride with a starch-polyvinyl alcohol composite solution and dry it; Then coat it with a modified polyacrylate resin and dry it to obtain multi-layer composite capsules; Prepare the graphene dispersion: Add graphene oxide to deionized water, add polyvinyl alcohol, and then perform ultrasonic treatment for 30-60 min to obtain the graphene dispersion; the mass percentage of the graphene oxide is 2-4 wt%; the mass percentage of the polyvinyl alcohol is 1-1.5 wt%; Step 2: Pour the polyurethane prepolymer into a reaction kettle, heat it to 55-65 °C, and stir evenly; then add the graphene dispersion prepared in Step 1 into the polyurethane prepolymer, and continue to stir for 20-30 min; then add fillers, plasticizers, ultraviolet absorbers, dispersants and organotin catalysts, and continue to stir for 20-30 min to obtain a mixture; the stirring speed is 500-800 revolutions / min; Step 3: Cool the temperature of the mixture obtained in Step 2 to room temperature, then add the multi-layer composite capsules prepared in Step 1 into it, and stir at a stirring speed of 50-100 revolutions / min for 3-5 min, then add a curing agent and stir evenly to obtain a one-component polyurethane rapid repair material for road potholes.

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