Polyurethane pavement material and preparation method thereof

Abstract

The invention discloses a polyurethane pavement material and a preparation method thereof, and belongs to the technical field of polyurethane pavement materials, and the polyurethane pavement material comprises the following raw material components in parts by mass: 1000 parts of aggregate, 15-30 parts of diisocyanate-terminated oligomer, 10-25 parts of polyfunctional group isocyanate, 5-15 parts of a diluent and 0.05-0.5 part of a catalyst. A large number of silica chain segments are introduced into the diisocyanate-terminated oligomer through hydroxyl silicone oil, so that the hydrophobicity and weather resistance of a polyurethane cementing material are greatly improved, and the water damage resistance of a polyurethane mixture is improved; a polybutadiene chain segment structure is introduced into the diisocyanate-terminated oligomer through hydroxyl-terminated polybutadiene or carboxyl-terminated polybutadiene, so that the activity of a molecular chain segment of the polyurethane cementing material is improved, and the low-temperature performance of the polyurethane cementing material and a mixture is improved.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane pavement materials technology, and in particular relates to a polyurethane pavement material and its preparation method. Background Technology

[0002] Asphalt pavement, as one of the most widely used road paving materials, boasts advantages such as good driving comfort, simple construction process, and low construction cost. However, asphalt is a temperature-sensitive material, significantly affected by temperature changes. It is prone to rutting under high summer temperatures and brittleness under low winter temperatures. Especially with the increasing frequency of extreme weather events, asphalt pavement materials are finding it increasingly difficult to meet practical application needs. To overcome the shortcomings of asphalt pavement materials, researchers have attempted to improve the performance of asphalt pavements by adding high-molecular polymers such as polyethylene, polypropylene, rubber, and polyurethane. Polyurethane adhesives, as a high-performance material with low temperature sensitivity, have gained increasing attention.

[0003] Polyurethane binders are inherently relatively hydrophilic polymers. During long-term road service, once moisture penetrates, prolonged water erosion causes the polyurethane binder to gradually degrade, leading to problems such as loosening and detachment of the polyurethane mixture, resulting in decreased water stability and durability. Currently, hydrophobic modification of polyurethane binders mainly relies on spraying nanomaterials to create a rough surface, which is essentially a simple physical modification method with limited effect on wear resistance. Patent CN118530425A provides a road-grade polyurethane urea binder based on a combination of physical modification (creating a rough surface) and chemical modification (low surface energy). By preparing a superhydrophobic surface and reducing the surface energy of the binder, its hydrophobic properties are improved. However, chemical modification methods hold greater promise for meeting long-term service performance requirements. Existing chemical modification methods are mostly fluorine modification, silicon modification, and modification with fluorinated end-capping agents, which can effectively improve the hydrophobic properties of polyurethane binders, but suffer from high cost, poor compatibility, and complex processes.

[0004] Improving the low-temperature crack resistance of polyurethane mixtures requires optimization of material formulation, adjustment of preparation process, dosage, and improvement of chemical structure. Traditional polyol-based polyurethane-modified asphalt preparation processes are mature and offer controllable performance, but suffer from limited low-temperature performance, insufficient flexibility, and slightly poor compatibility. Patent CN115948056A discloses a method for preparing hydroxyl-terminated polybutadiene-based polyurethane-modified asphalt. This modified asphalt exhibits excellent low-temperature crack resistance and superior storage stability, confirming the feasibility of hydroxyl-terminated polybutadiene as a polyol and demonstrating good engineering application value. However, the polyurethane-modified asphalt prepared by this patent contains a high proportion of hydroxyl-terminated polybutadiene (over 80%), has a simple modification mechanism, high cost, and its effect on improving the low-temperature performance of the mixture has not yet been proven.

[0005] Based on the above problems, it is necessary to develop a polyurethane pavement material from the perspective of material formulation design, so that it has excellent water damage resistance and low temperature performance. Summary of the Invention

[0006] The purpose of this invention is to provide a polyurethane pavement material and its preparation method to solve the problems existing in the prior art. This invention significantly improves the hydrophobicity and molecular chain mobility of polyurethane binders by introducing hydroxyl silicone oil and polybutadiene compounds into diisocyanate end-group oligomers, thereby improving the water damage resistance and low-temperature performance of polyurethane mixtures.

[0007] One of the technical solutions provided by this invention:

[0008] A polyurethane pavement material, by weight, comprises the following components: 1000 parts aggregate, 15-30 parts diisocyanate end-group oligomer, 10-25 parts polyfunctional isocyanate, 5-15 parts diluent, and 0.05-0.5 parts catalyst.

[0009] Furthermore, the aggregate is one or more of basalt, limestone, granite and quartz sand, and the aggregate gradation is a continuous dense gradation.

[0010] Furthermore, the preparation method of the diisocyanate end-group oligomer includes the following steps: slowly adding component A dropwise to heated and stirred diisocyanate; after the dropwise addition is complete, adding a catalyst and continuing to stir the reaction to obtain the diisocyanate end-group oligomer; wherein, the raw materials of component A include polyether diol, hydroxyl silicone oil and polybutadiene compounds.

[0011] Furthermore, the mass ratio of the polyether diol, hydroxyl silicone oil and polybutadiene compound is (1-3):1:(0.5-1); and / or, the mass ratio of the diisocyanate and component A is 1:(3-4).

[0012] The mass of hydroxyl silicone oil is 45-75% of the sum of the mass of polyether diol and hydroxyl silicone oil; the addition of hydroxyl silicone oil can effectively improve the low-temperature performance and hydrophobic properties of the product.

[0013] The polyether diol is selected from PPG (polypropylene glycol) or PTMEG (polytetrahydrofuran alcohol). The polyether diol contains ether bonds in its molecular structure, exhibiting good hydrolytic stability and excellent low-temperature performance, maintaining good elasticity and flexibility even at low temperatures. The hydroxyl silicone oil has a molecular weight range of 500–2500 g / mol; it is a linear polymer with repeating siloxane bonds (Si-O-Si) as the main chain, methyl groups as side groups, and hydroxyl groups at the end, possessing good weather resistance and hydrophobicity; by introducing a large number of siloxane segments into the diisocyanate end-group oligomers, the water damage resistance of the polyurethane blend can be improved.

[0014] The polybutadiene compounds include one or both of hydroxyl-terminated polybutadiene and carboxyl-terminated polybutadiene. Hydroxyl-terminated polybutadiene is a diol with a molecular weight of 1500–3500 g / mol. Hydroxyl-terminated polybutadiene is a low-molecular-weight telechelic liquid rubber whose elastomer crosslinking network contains no free segments and has a regular and uniform crosslinking mesh, thus exhibiting excellent mechanical properties. Its participation in prepolymer preparation can supplement polyether diols. Simultaneously, this polybutadiene segment structure helps improve the mobility of polyurethane binder molecular segments, enhancing the low-temperature performance of polyurethane binders and mixtures. Hydroxyl-terminated polybutadiene exceeding this molecular weight range suffers from over-crosslinking due to excessively low molecular weight, affecting its low-temperature performance; excessively high molecular weight cannot guarantee the crosslinking density, resulting in minimal performance improvement. Carboxyl-terminated polybutadiene exhibits similar effects.

[0015] The diisocyanate is selected from one or more of aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates, preferably one of TDI (toluene diisocyanate), HMDI (dicyclohexylmethane diisocyanate), and IPDI (isophorone diisocyanate).

[0016] Furthermore, the raw materials for component A also include polydimethylsiloxane alcohol.

[0017] Polydimethylsiloxane alcohol has similar effects to hydroxyl silicone oil, but its modification effect is better. However, it has higher reactivity and higher cost, so it can be added in small amounts to improve its performance. The amount of polydimethylsiloxane alcohol added is 10%-50% of the hydroxyl silicone oil (replacement amount), and its molecular weight is 300-4500 g / mol. If the molecular weight is too low, the performance stability will be affected; if the molecular weight is too high, there will be fewer functional groups and it will be impossible to form a dense hydrophobic layer.

[0018] Furthermore, the heating temperature is 60–80°C; and / or the dropping rate is 1–2 mL / min; and / or the stirring time is 60–120 min.

[0019] Furthermore, the polyfunctional isocyanate is a polymeric diphenylmethane diisocyanate. Polyfunctional compounds can introduce crosslinking points, forming a three-dimensional network structure, thereby improving the mechanical properties and heat resistance of the material. This compound has a low cost and a high isocyanate content, which can accelerate the reaction process and meet the needs of cold-mix preparation.

[0020] Furthermore, the diluent is prepared by compounding waste edible oil and line-reducing oil at a mass ratio of (2-5):1. Line-reducing oil, as a petroleum byproduct, has good hydrophobicity and relatively stable chemical properties. Its main components include organic compounds such as aromatics, alkanes, and cycloalkanes. Adding an appropriate amount to the preparation of polyurethane pavement materials allows it to dissolve with the components in the polyurethane mixture, effectively reducing the viscosity of the polyurethane system. Selecting a compounding ratio of waste edible oil and line-reducing oil within this range can reduce viscosity, ensure workability during construction, and simultaneously utilize the main component of the diluent—waste edible oil—reducing costs while demonstrating the environmental value of the material.

[0021] Furthermore, the catalyst is selected from one of triethylenediamine, dibutyltin dilaurate, cobalt isooctanoate, and N,N-dimethylaniline. Using a catalyst can improve the reaction activity and accelerate the reaction rate.

[0022] The second technical solution provided by this invention:

[0023] A method for preparing the above-mentioned polyurethane pavement material includes the following steps: weighing raw materials according to the mass fraction, mixing diisocyanate end-group oligomer, polyfunctional isocyanate, diluent and catalyst at room temperature to obtain component B; mixing component B with aggregate at room temperature for 60-80s; molding the mixture and then curing it to obtain the polyurethane pavement material.

[0024] Furthermore, the curing process includes: first, curing in a constant temperature and humidity environment of 20℃~35℃ and 55%~65% for 20~30 hours; then raising the temperature to 55℃~80℃ and the humidity to 70%~80%, and continuing curing for 60h~80h.

[0025] Compared with the prior art, the present invention has the following advantages and technical effects:

[0026] This invention introduces a large number of siloxane segments into diisocyanate end-group oligomers via hydroxyl silicone oil, thereby significantly improving the hydrophobicity and weather resistance of polyurethane binders and enhancing the water damage resistance of polyurethane blends. Furthermore, the introduction of polybutadiene segment structures into diisocyanate end-group oligomers via hydroxyl-terminated polybutadiene or carboxyl-terminated polybutadiene helps to improve the mobility of polyurethane binder molecular chains and enhance the low-temperature performance of polyurethane binders and blends. Detailed Implementation

[0027] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0028] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0029] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0030] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0031] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0032] This invention provides a polyurethane pavement material, which, by weight, comprises the following components: 1000 parts aggregate, 15-30 parts diisocyanate-terminated oligomer, 10-25 parts polyfunctional isocyanate compound, 5-15 parts diluent, and 0.05-0.5 parts catalyst. For example, the aggregate is 1000 parts, the diisocyanate-terminated oligomer is 20 parts, 22 parts, or any range between the aforementioned parts, the polyfunctional isocyanate compound is 15 parts, 16 parts, or any range between the aforementioned parts, the diluent is 8 parts, 10 parts, or any range between the aforementioned parts, and the catalyst is 0.3 parts, 0.4 parts, or 0.5 parts, or any range between the aforementioned parts.

[0033] Compared to traditional road surface materials, this invention introduces hydroxyl silicone oil and hydroxyl-terminated polybutadiene liquid rubber into isocyanate oligomers. By utilizing the structural characteristics of the additives themselves, the weather resistance and low-temperature crack resistance of the material are improved, so that polyurethane pavement can have excellent road performance even at a low level of isocyanate prepolymer content.

[0034] In some embodiments of the present invention, the aggregate is one or more selected from basalt, limestone, granite, and quartz sand, and the aggregate gradation is a continuous dense gradation. For example, the aggregate is basalt, which has the highest polishing value among common aggregates and good adsorption to polyurethane adhesives.

[0035] The aggregate gradation range is as follows: 100% passing through a 13.2mm sieve, 90-100% passing through a 9.5mm sieve, 35-55% passing through a 4.75mm sieve, 24-30% passing through a 2.36mm sieve, 16-24% passing through a 1.18mm sieve, 11-19% passing through a 0.6mm sieve, 7-13% passing through a 0.3mm sieve, 5-9% passing through a 0.15mm sieve, and 0-5% passing through a 0.075mm sieve. The aggregate gradation is generally designed based on the maximum density packing theory, and is continuously optimized and improved based on the distribution and shape characteristics of specific batches of aggregate through specific experiments. This gradation exhibits good compactness and waterproof performance. Using this type of aggregate with a specific gradation allows polyurethane concrete to achieve more stable strength.

[0036] In some embodiments of the present invention, the diisocyanate-terminated oligomer is prepared by reacting component A, which is formed by combining polyether diol, hydroxyl silicone oil and polybutadiene compound, with diisocyanate compound. The specific preparation method includes the following steps:

[0037] S1: First, polyether diol, hydroxyl silicone oil and polybutadiene compounds are mixed in a mass ratio of (1-3):1:(0.5-1) to prepare component A;

[0038] S2: Place the diisocyanate compound in a reactor, heat it to 60-80°C, and stir continuously at a rate of 200-500 rpm; the mass ratio of the diisocyanate to component A is 1:(3-4).

[0039] S3: Slowly add component A to the diisocyanate compound, controlling the addition time to 60-80 min;

[0040] S4: After the addition is complete, add the catalyst and continue stirring for 60-120 minutes to obtain diisocyanate end-group oligomers.

[0041] In some embodiments of the present invention, the raw material of component A further includes polydimethylsiloxane alcohol;

[0042] For example, the mass ratio of polyether diol: hydroxyl silicone oil: polybutadiene compound: polydimethylsiloxane alcohol is 3:1:0.5:0.5.

[0043] In some embodiments of the present invention, the polyfunctional isocyanate is a polymeric diphenylmethane diisocyanate.

[0044] In some embodiments of the present invention, the polyether diol is selected from PPG (polypropylene glycol) or PTMEG (polytetrahydrofuran alcohol); the polybutadiene compound includes one or both of hydroxyl-terminated polybutadiene and carboxyl-terminated polybutadiene. The diisocyanate includes one or more of aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates, and in some preferred embodiments, is one of TDI (toluene diisocyanate), HMDI (dicyclohexylmethane diisocyanate), and IPDI (isophorone diisocyanate).

[0045] In some embodiments of the present invention, the diluent is prepared by combining waste edible oil and anti-corrosion oil in a mass ratio of (5-2):1; for example, the mass ratio of waste edible oil to anti-corrosion oil is 3:1, 4:1 and 2:1.

[0046] This invention also provides a method for preparing the above-mentioned polyurethane pavement material, comprising the following steps: weighing raw materials according to mass parts, uniformly mixing diisocyanate end-group oligomers, polyfunctional isocyanate compounds, diluents and catalysts at room temperature for 5 minutes, labeling it as component B, and storing it at room temperature in the dark for later use; mixing aggregates with a certain gradation with component B at room temperature for 60-80 seconds; after molding the mixture, first curing it in a constant temperature and humidity environment of 20℃-35℃ and 55%-65% for 20-30 hours; then increasing the curing temperature and humidity to 55℃-80℃ and 70%-80% respectively, and continuing curing for 60-80 hours; after curing, a high-performance polyurethane mixture is obtained, and finally, relevant road performance tests are conducted.

[0047] The required aggregate gradation range in this embodiment of the invention is as follows: 100% pass rate through a 13.2mm sieve, 95% pass rate through a 9.5mm sieve, 50% pass rate through a 4.75mm sieve, 28% pass rate through a 2.36mm sieve, 22% pass rate through a 1.18mm sieve, 17% pass rate through a 0.6mm sieve, 11% pass rate through a 0.3mm sieve, 8% pass rate through a 0.15mm sieve, and 2% pass rate through a 0.075mm sieve. As a typical but not limiting example, in this embodiment of the invention, the polyether diol is PPG (polypropylene glycol) with a molecular weight of 1000 g / mol; the diisocyanate is TDI (toluene diisocyanate); the catalyst is dibutyltin dilaurate; the polybutadiene compound is hydroxyl-terminated polybutadiene with a molecular weight of 2000 g / mol, the hydroxyl silicone oil has a molecular weight of 1000 g / mol, and the polydimethylsiloxane alcohol has a molecular weight of 1300 g / mol.

[0048] The room temperature in this invention refers to 25±2℃.

[0049] In the embodiments of this invention, unless otherwise specified, "parts" refers to "parts by mass".

[0050] Example 1: A method for preparing a polyurethane pavement material

[0051] (1) Preparation of diisocyanate-terminated oligomers:

[0052] S1. Mix polypropylene glycol, hydroxyl silicone oil and hydroxyl-terminated polybutadiene in a mass ratio of 3:1:1 to obtain component A;

[0053] S2. Place diisocyanate (toluene diisocyanate) in a reactor, heat to 80°C, and stir continuously at a rate of 300 rpm. The mass ratio of diisocyanate to component A is 1:3.4.

[0054] S3. Slowly add component A dropwise to diisocyanate (toluene diisocyanate) at a rate of 2 mL / min;

[0055] S4. After the addition is complete, add the catalyst (dibutyltin dilaurate, the catalyst is 0.05% of the mass of the mixture), and continue stirring for 110 min to obtain the diisocyanate end-group oligomer.

[0056] (2) Preparation of polyurethane pavement materials

[0057] S1. Weigh 20 parts of the diisocyanate end-group oligomer obtained in step (1), 15 parts of the polyfunctional isocyanate compound (polydiphenylmethane diisocyanate), 8 parts of the diluent (waste cooking oil: reduced oil = 3:1), and 0.3 parts of the catalyst (dibutyltin dilaurate). Mix them evenly at room temperature for 5 minutes and record them as component B. Store them at room temperature away from light for later use.

[0058] S2. Mix 1000 parts of aggregate with component B at room temperature for 60 seconds;

[0059] S3. After the mixture is shaped, it is first cured in a constant temperature and humidity environment of 25℃ and 55% for 24 hours; then the curing temperature and humidity are increased to 60℃ and 72% respectively, and the curing continues for 80 hours.

[0060] S4. After the curing is completed, the polyurethane pavement material is obtained, and finally, relevant road performance tests (Marshall stability, failure strain and freeze-thaw splitting strength ratio) are conducted.

[0061] Example 2: A method for preparing a polyurethane road surface material

[0062] (1) Preparation of diisocyanate-terminated oligomers

[0063] S1. Mix polypropylene glycol, hydroxyl silicone oil and hydroxyl-terminated polybutadiene in a mass ratio of 2:1:0.5 to obtain component A;

[0064] S2. Place the diisocyanate compound (toluene diisocyanate) in a reactor, heat it to 70°C, and stir continuously at a rate of 400 rpm. The mass ratio of diisocyanate to component A is 1:3.3.

[0065] S3. Slowly add component A dropwise to the diisocyanate compound (toluene diisocyanate) at a rate of 2 mL / min;

[0066] S4. After the addition is complete, add the catalyst (dibutyltin dilaurate, the catalyst is 0.05% of the mass of the mixture), and continue stirring for 100 min to obtain the diisocyanate end-group oligomer.

[0067] (2) Preparation of polyurethane pavement materials

[0068] S1. Weigh 22 parts of the diisocyanate end-group oligomer, 16 parts of the polyfunctional isocyanate compound (polydiphenylmethane diisocyanate), 10 parts of the diluent (waste cooking oil: reduced oil = 4:1), and 0.5 parts of the catalyst (dibutyltin dilaurate) obtained in step (1). Mix them evenly at room temperature for 5 minutes and record them as component B. Store them at room temperature away from light for later use.

[0069] S2. Mix 1000 parts of aggregate with component B at room temperature for 60 seconds;

[0070] S3. After the polyurethane mixture is mixed and shaped, it is first cured in a constant temperature and humidity environment of 25℃ and 60% for 22 hours; then the curing temperature and humidity are increased to 70℃ and 75% respectively, and the curing continues for 70 hours.

[0071] S4. After the curing is completed, the polyurethane pavement material is obtained, and finally, relevant road performance tests (Marshall stability, failure strain and freeze-thaw splitting strength ratio) are conducted.

[0072] Example 3: A method for preparing a polyurethane road surface material

[0073] (1) Preparation of diisocyanate-terminated oligomers

[0074] S1. Mix polypropylene glycol, hydroxyl silicone oil, polydimethylsiloxane alcohol and hydroxyl-terminated polybutadiene polydimethylsiloxane alcohol in a mass ratio of 3:1:0.5:0.5 to obtain component A;

[0075] S2. Place the diisocyanate compound (toluene diisocyanate) in a reactor, heat it to 60°C, and stir continuously at a rate of 500 rpm. The mass ratio of diisocyanate to component A is 1:3.2.

[0076] S3. Slowly add component A dropwise to the diisocyanate compound (toluene diisocyanate) at a rate of 1 mL / min;

[0077] S4. After the addition is complete, add the catalyst (dibutyltin dilaurate, the catalyst is 0.05% of the mass of the mixture), and continue stirring for 110 min to obtain the diisocyanate end-group oligomer.

[0078] (2) Preparation of polyurethane pavement materials

[0079] S1. Weigh 22 parts of the diisocyanate end-group oligomer, 16 parts of the polyfunctional isocyanate compound (polydiphenylmethane diisocyanate), 10 parts of the diluent (waste cooking oil: reduced oil = 2:1), and 0.4 parts of the catalyst (dibutyltin dilaurate) obtained in step (1). Mix them evenly at room temperature for 5 minutes and record them as component B. Store them at room temperature away from light for later use.

[0080] S2. Mix 1000 parts of aggregate with component B at room temperature for 60 seconds;

[0081] S3. After the mixture is shaped, it is first cured in a constant temperature and humidity environment of 25℃ and 65% for 20 hours; then the curing temperature and humidity are increased to 75℃ and 80% respectively, and the curing continues for 62 hours.

[0082] S4. After the curing is completed, the polyurethane pavement material is obtained, and finally, relevant road performance tests (Marshall stability, failure strain and freeze-thaw splitting strength ratio) are conducted.

[0083] Example 4: A method for preparing a polyurethane road surface material

[0084] (1) Preparation of diisocyanate-terminated oligomers:

[0085] S1. Mix polypropylene glycol, hydroxyl silicone oil and hydroxyl-terminated polybutadiene in a mass ratio of 1:1:0.5 to obtain component A;

[0086] S2. Place diisocyanate (toluene diisocyanate) in a reactor, heat to 80°C, and stir continuously at a rate of 200 rpm. The mass ratio of diisocyanate to component A is 1:3.4.

[0087] S3. Slowly add component A dropwise to diisocyanate (toluene diisocyanate) at a rate of 2 ml / min;

[0088] S4. After the addition is complete, add the catalyst (dibutyltin dilaurate, the catalyst is 0.05% of the mass of the mixture), and continue stirring for 60 minutes to obtain the diisocyanate end-group oligomer.

[0089] (2) Preparation of polyurethane pavement materials

[0090] S1. Weigh 15 parts of the diisocyanate end-group oligomer obtained in step (1), 10 parts of the polyfunctional isocyanate compound (polydiphenylmethane diisocyanate), 5 parts of the diluent (waste cooking oil: reduced oil = 5:1), and 0.2 parts of the catalyst (dibutyltin dilaurate). Mix them evenly at room temperature for 5 minutes and record them as component B. Store them at room temperature away from light for later use.

[0091] S2. Mix 1000 parts of aggregate with component B at room temperature for 70 seconds;

[0092] S3. After the mixture is shaped, it is first cured in a constant temperature and humidity environment of 20℃ and 55% for 20 hours; then the curing temperature and humidity are increased to 55℃ and 70% respectively, and the curing continues for 60 hours.

[0093] S4. After the curing is completed, the polyurethane pavement material is obtained, and finally, relevant road performance tests (Marshall stability, failure strain and freeze-thaw splitting strength ratio) are conducted.

[0094] Example 5: A method for preparing a polyurethane road surface material

[0095] (1) Preparation of diisocyanate-terminated oligomers:

[0096] S1. Mix polypropylene glycol, hydroxyl silicone oil, polydimethylsiloxane alcohol and hydroxyl-terminated polybutadiene in a mass ratio of 1:2:0.5:1 to obtain component A;

[0097] S2. Place diisocyanate (toluene diisocyanate) in a reactor, heat to 60°C, and stir continuously at a rate of 200 rpm. The mass ratio of diisocyanate to component A is 1:3.6.

[0098] S3. Slowly add component A dropwise to diisocyanate (toluene diisocyanate) at a rate of 2 mL / min;

[0099] S4. After the addition is complete, add the catalyst (dibutyltin dilaurate, the catalyst is 0.05% of the mass of the mixture), and continue stirring for 120 min to obtain the diisocyanate end-group oligomer.

[0100] (2) Preparation of polyurethane pavement materials

[0101] S1. Weigh 30 parts of the diisocyanate end-group oligomer obtained in step (1), 25 parts of the polyfunctional isocyanate compound (polydiphenylmethane diisocyanate), 15 parts of the diluent (waste cooking oil: reduced oil = 3:1), and 0.5 parts of the catalyst (dibutyltin dilaurate). Mix them evenly at room temperature for 5 minutes and record them as component B. Store them at room temperature away from light for later use.

[0102] S2. Mix 1000 parts of aggregate with component B at room temperature for 80 seconds;

[0103] S3. After the mixture is shaped, it is first cured in a constant temperature and humidity environment of 35℃ and 60% for 30 hours; then the curing temperature and humidity are increased to 80℃ and 75% respectively, and the curing continues for 80 hours.

[0104] S4. After the curing is completed, the polyurethane pavement material is obtained, and finally, relevant road performance tests (Marshall stability, failure strain and freeze-thaw splitting strength ratio) are conducted.

[0105] Comparative Example 1

[0106] Same as Example 1, except that the mass ratio of polypropylene glycol, hydroxyl silicone oil and hydroxyl-terminated polybutadiene in the preparation of diisocyanate-terminated oligomers is 3:0.5:0.1.

[0107] Comparative Example 2

[0108] Same as Example 1, except that the mass ratio of polypropylene glycol, hydroxyl silicone oil and hydroxyl-terminated polybutadiene is 1:2:1 in the preparation of diisocyanate-terminated oligomers.

[0109] Comparative Example 3

[0110] Same as Example 1, except that in the preparation of polyurethane pavement material, 20 parts of diisocyanate end-group oligomer, 2 parts of polyfunctional isocyanate compound (polydiphenylmethane diisocyanate), 8 parts of diluent (waste cooking oil: reduced oil = 3:1), and 0.3 parts of catalyst (dibutyltin dilaurate) were weighed and mixed evenly at room temperature for 5 minutes. This mixture was recorded as component B and stored at room temperature away from light for later use.

[0111] Comparative Example 4

[0112] Similar to Example 1, the only difference is that in the preparation of polyurethane pavement material, after the mixture is shaped, it is first cured in a constant temperature and humidity environment of 25°C and 55% for 24 hours; then the curing temperature and humidity are increased to 40°C and 72% respectively, and the curing continues for 80 hours.

[0113] Comparative Example 5

[0114] Similar to Example 1, the only difference is that in the preparation of polyurethane pavement material, after the mixture is molded, it is first cured in a constant temperature and humidity environment of 25°C and 55% for 24 hours; then the curing temperature and humidity are increased to 100°C and 72% respectively, and the curing continues for 80 hours.

[0115] Comparative Example 6

[0116] Similar to Example 1, the only difference is that in the preparation of polyurethane pavement material, after the mixture is molded, it is first cured in a constant temperature and humidity environment of 25°C and 55% for 24 hours; then the curing temperature and humidity are adjusted to 60°C and 52% respectively, and the curing continues for 80 hours.

[0117] Comparative Example 7

[0118] Similar to Example 1, the only difference is that in the preparation of polyurethane pavement material, after the mixture is shaped, it is first cured in a constant temperature and humidity environment of 25°C and 55% for 24 hours; then the curing temperature and humidity are increased to 60°C and 92% respectively, and the curing continues for 80 hours.

[0119] Comparative Example 8

[0120] Same as Example 1, except that no polybutadiene compounds were added.

[0121] Comparative Example 9

[0122] Same as Example 1, except that the polyether diol, hydroxyl silicone oil and polybutadiene compound are in a mass ratio of 3:1:0.1.

[0123] Comparative Example 10

[0124] Same as Example 1, except that the polyether diol, hydroxyl silicone oil and polybutadiene compound are in a mass ratio of 3:1:10.

[0125] Performance testing

[0126] The polyurethane pavement materials prepared in Examples 1-5 and Comparative Examples 1-10 were subjected to the T 0709-2011 Marshall test, T 0715-2011 flexural test, and T 0729-2000 freeze-thaw splitting test (according to the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011)) to analyze and determine their road performance. A higher Marshall stability value indicates a more reasonable asphalt mixture formulation for the polyurethane pavement material, suggesting that the mixture may have good high-temperature stability and load-bearing capacity. A higher failure strain value indicates better low-temperature performance of the polyurethane pavement material. The freeze-thaw splitting strength ratio reflects the water stability of the polyurethane pavement material. The test results are shown in Table 1.

[0127] Table 1

[0128]

[0129]

[0130] By comparing the performance data measured in Example 1, Comparative Example 1, and Comparative Example 2, it was found that if the amount of hydroxyl silicone oil in the preparation process of diisocyanate end-group oligomers was too low, the water damage resistance of the polyurethane pavement material was not significantly improved; if the amount of hydroxyl silicone oil was relatively too high, the content of polyol and hydroxyl-terminated polybutadiene in component A decreased, which affected the high and low temperature performance of the polyurethane pavement material and resulted in higher costs.

[0131] By comparing the performance data measured in Example 1 and Comparative Example 3, it is shown that in the preparation process of polyurethane pavement materials, if the amount of polyfunctional isocyanate compound (polymer diphenylmethane diisocyanate) is too small, it will affect the curing speed and have limited performance improvement.

[0132] By comparing Example 1, Comparative Example 4, and Comparative Example 5, it is shown that in the preparation process of polyurethane pavement materials, if the curing temperature is too low, the curing is too slow and the design strength is not reached within the curing time; if the curing temperature is too high, the curing is too fast, which is not conducive to construction and maintenance.

[0133] By comparing Example 1, Comparative Example 6, and Comparative Example 7, it is shown that in the preparation process of polyurethane pavement materials, if the curing humidity is too low, the reaction will not be complete within the curing time, which will affect the performance of the mixture, and the curing will be too slow, which is not conducive to construction and maintenance. If the curing humidity is too high, the cohesion of the polyurethane mixture will decrease, and the high and low temperature performance and water damage resistance will be affected. In addition, the curing will be too fast, which is not conducive to construction and maintenance.

[0134] By comparing Example 1, Comparative Example 8, Comparative Example 9 and Comparative Example 10, it is shown that when preparing diisocyanate-terminated oligomers, if the amount of hydroxyl-terminated polybutadiene is too small, the low-temperature performance of the material will decrease significantly; if the amount of hydroxyl-terminated polybutadiene is too large, the content of polyether diol will decrease, the high-temperature performance will not be significantly improved, and the excessive amount of hydroxyl-terminated polybutadiene will increase the preparation cost.

[0135] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A polyurethane road surface material, characterized in that, The raw materials, by weight, include the following components: 1000 parts aggregate, 15-30 parts diisocyanate end-group oligomer, 10-25 parts polyfunctional isocyanate, 5-15 parts diluent, and 0.05-0.5 parts catalyst.

2. The polyurethane pavement material according to claim 1, characterized in that, The aggregate is selected from one or more of basalt, limestone, granite and quartz sand; the aggregate has a continuous dense gradation.

3. The polyurethane pavement material according to claim 1, characterized in that, The preparation method of the diisocyanate end-group oligomer includes the following steps: slowly adding component A dropwise to heated and stirred diisocyanate; after the dropwise addition is complete, adding a catalyst and continuing to stir the reaction to obtain the diisocyanate end-group oligomer. The raw materials for component A include polyether diol, hydroxyl silicone oil, and polybutadiene compounds.

4. The polyurethane pavement material according to claim 3, characterized in that, The mass ratio of the polyether diol, hydroxyl silicone oil and polybutadiene compound is (1-3):1:(0.5-1); and / or the mass ratio of the diisocyanate and component A is 1:(3-4).

5. The polyurethane pavement material according to claim 3, characterized in that, The raw materials for component A also include polydimethylsiloxane alcohol.

6. The polyurethane pavement material according to claim 3, characterized in that, The heating temperature is 60–80°C; and / or the dropping rate is 1–2 mL / min; and / or the stirring time is 60–120 min.

7. The polyurethane pavement material according to claim 1, characterized in that, The polyfunctional isocyanate is a polymeric diphenylmethane diisocyanate.

8. The polyurethane pavement material according to claim 1, characterized in that, The diluent is prepared by combining waste cooking oil and reduced-density oil in a mass ratio of (2-5):

1.

9. A method for preparing a polyurethane pavement material according to any one of claims 1 to 8, characterized in that, The process includes the following steps: Weigh the raw materials according to the mass fraction, and mix the diisocyanate end-group oligomer, polyfunctional isocyanate, diluent and catalyst at room temperature to obtain component B; The component B is mixed with the aggregate at room temperature for 60-80 seconds; the resulting mixture is then shaped and cured to obtain the polyurethane pavement material.

10. The preparation method according to claim 9, characterized in that, The curing process includes: first, curing in a constant temperature and humidity environment of 20℃~35℃ and 55%~65% for 20~30 hours; then raising the temperature to 55℃~80℃ and the humidity to 70%~80%, and continuing curing for 60h~80h.

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