A high-performance polyurethane-polyurea composite material, its preparation method and application

Abstract

The present invention discloses a high-performance polyurethane-polyurea composite material, its preparation method and application, which includes two-component polyurethane and polyurea, and the dosage of polyurea is 15-20%; the two-component polyurethane is prepared by the following method: mixing polyester polyol (component A) and isocyanate curing agent (component B) according to a mass ratio of 3-5:1, mixing and stirring at a speed of 150-350 rpm for 3-5 minutes, and standing for 1-2 minutes. Among them, polyurea is polymerized from an amino compound and isocyanate according to a mass ratio of 1:1, the initial curing time at 20 °C is 1.5-2.0 h, and the complete curing time is 45-50 h. The high-performance polyurethane-polyurea composite material disclosed by the present invention uses polyurea in a specific proportion to modify polyurethane, and the modified composite material has high strength, high toughness, good low-temperature performance and water resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyurethane modified materials, and particularly relates to a high-performance polyurethane-polyurea composite material, a preparation method thereof and an application thereof. Background Art

[0002] With the increase of the service life of roads, the surface function of the road surface decays year by year, seriously affecting the daily travel safety and reducing the service level of the road. It is necessary to restore the surface function of the road surface by means of thin layer or ultra-thin layer surfacing. Therefore, preventive maintenance technologies such as slurry seal, microsurfacing, thin layer surfacing, OGFC, Novechip ultra-thin wearing course, etc. have been rapidly developed and applied. However, with "safety" and "environment" gradually becoming the theme of road construction, traditional black road surface technologies can no longer meet the needs of road traffic. The research and application of polymer resin materials have broken the traditional asphalt-based material maintenance means. Replacing asphalt with resin-based adhesives, and after adding corresponding pigments, they are used in combination with colored anti-skid aggregates to form a new type of pre-maintenance technology - resin-based colored ultra-thin layer road surface. Among them, the resin-based adhesive mainly plays the role of bonding with the underlying layer and aggregates, and at the same time seals the water of the old road surface; the anti-skid aggregates play the role of anti-skid and wear resistance. This pre-maintenance technology can not only improve the anti-skid and wear resistance of the original road surface, but also make the road surface completely impermeable after maintenance, fully protect the road surface structure, and can also fill the micro-cracks of the road surface, achieving the purpose of extending the service life of the road surface, improving the safe passing ability, and improving the driving environment to play a warning role for drivers.

[0003] The commonly used resin adhesives for colored ultra-thin layer road surfaces mainly include epoxy resin, polyurethane resin, acrylic resin and polyurea. Among them, epoxy resin has high strength, but poor toughness, low temperature performance and weather resistance; methyl methacrylate has good toughness, but strong toxicity, poor weather resistance and water resistance, and cures quickly and is not suitable for large-area construction; polyurethane resin has good adhesion and weather resistance, but poor chemical corrosion resistance and insufficient mechanical properties, etc.; polyurea has good toughness, but low strength and high cost itself. The four adhesives have different performances and each has its own advantages and disadvantages, which makes the bonding strength of the colored ultra-thin layer road surface decrease under the action of long-term load, water and temperature, and diseases such as cracking and delamination often occur. Therefore, it is urgent to prepare resin adhesive materials with high toughness, high strength, good water resistance and low temperature performance to meet the needs of various fields, especially the needs of colored ultra-thin layer road surfaces. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-performance polyurethane-polyurea composite material and a preparation method thereof, so that the composite material obtained by modifying polyurethane with polyurea has high strength, toughness, water stability and good low temperature performance.

[0005] To achieve the above object, the present invention provides a high-performance polyurethane-polyurea composite material, which comprises two-component polyurethane and polyurea, and the dosage of polyurea is 15-20%.

[0006] Further, the dosage of polyurea is 20 wt% of the two-component polyurethane.

[0007] Further, the two-component polyurethane is prepared by the following method: mixing polyester polyol and isocyanate curing agent in a mass ratio of 3-5:1, mixing and stirring at a speed of 150-350 rpm for 3-5 min, and standing for 1-2 min. The initial curing time of the two-component polyurethane at 25 °C is 3.5-6.5 h.

[0008] Further, the two-component polyurethane is prepared by the following method: mixing polyester polyol (component A) and isocyanate curing agent (component B) in a mass ratio of 4:1, mixing and stirring at a speed of 200 rpm for 5 min, and standing for 2 min. The initial curing time of the two-component polyurethane at 25 °C is 6.5 h.

[0009] Further, the polyurea is polymerized from an amino compound and an isocyanate in a mass ratio of 1-2:1-2. The initial curing time at 20 °C is 1.5-2.0 h, and the complete curing time is 45-50 h.

[0010] Further, the polyurea is polymerized from an amino compound and an isocyanate in a mass ratio of 1:1. The initial curing time at 20 °C is 1.5 h, and the complete curing time is 48 h.

[0011] Further, the solid content of the polyester polyol (component A) is not less than 98%, the density is 2.0-2.1 g / cm 3 , the viscosity is 2000 mPa·s, the solid content of the isocyanate curing agent (component B) is not less than 98%, and the density is 1-1.5 g / cm 3 , and the viscosity is 3000 mPa·s.

[0012] Further, the solid content of the polyurea (A'+B') is 100%, the density is 1.0-1.1 g / cm 3 , and the viscosity is 2000-2200 mPa·s.

[0013] Further, the dosage of polyurea is 15-20%.

[0014] The present invention also discloses a preparation method of the above high-performance polyurethane-polyurea composite material, which comprises the following steps: separately preparing polyurea and polyurethane, then adding the polyurea into the polyurethane according to the dosage, and then mixing and stirring at a speed of 100-300 rpm for 3-5 min to obtain the product.

[0015] The present invention also discloses the application of the above-mentioned high-performance polyurethane-polyurea composite material in the preparation of epoxy floor paint coatings.

[0016] The present invention also discloses the application of the above-mentioned high-performance polyurethane-polyurea composite material in the preparation of road adhesives.

[0017] The present invention also discloses the application of the above-mentioned high-performance polyurethane-polyurea composite material in the preparation of thermal insulation boards.

[0018] In summary, the present invention has the following advantages:

[0019] 1. By mixing and modifying polyurea with polyurethane, the present invention can improve various properties of the composite material, including strength, toughness (tensile property), low-temperature property, and water resistance.

[0020] 2. By adjusting the dosage of polyurea, the present invention can selectively control the property changes of the composite material to adapt to applications in different environments. For example, in road adhesives, specifically, when the dosage range of polyurea is 15-20%, the tensile strength ≥ 6 MPa, the elongation at break ≥ 45%, and it has excellent tensile properties; at -6°C, the stiffness modulus S ≤ 300 MPa, and the creep rate m ≥ 0.13, which has excellent low-temperature properties compared with the two-component polyurethane before modification; the wet wheel abrasion value within 1 h ≤ 540 g / m 2 , and the wet wheel abrasion value within 6 d ≤ 800 g / m 2 , and it has excellent water resistance.

[0021] 3. The composite material prepared by the present invention with a polyurea dosage of 20% has a maximum tensile strength of 6.42 MPa and an elongation at break of 53.24%; for the polyurethane before modification, within the set low-temperature range (-6°C to 24°C), the stiffness modulus ranges from 426 to 791 MPa, and the creep rate is 0.047 to 0.087. After modification with polyurea, the stiffness modulus range drops to 246 to 487 MPa, and the creep rate is 0.065 to 0.142. Description of the Drawings

[0022] Figure 1 Preliminarily determined based on the dosage of the curing agent for the tensile property of polyurethane;

[0023] Figure 2 Specifically determined based on the dosage of the curing agent for the tensile property of polyurethane;

[0024] Figure 3 Relationship between age and tensile property;

[0025] Figure 4 Effect of polyurea dosage on the tensile property of polyurethane;

[0026] Figure 5The variation of the stiffness modulus of polyurethane with temperature at different polyurea dosages;

[0027] Figure 6 The variation of the creep rate of polyurethane with temperature at different polyurea dosages;

[0028] Figure 7 The results of the 1h wet wheel abrasion test of unmodified polyurethane;

[0029] Figure 8 The change in the water resistance of polyurethane before and after polyurea modification;

[0030] Figure 9 The comparison of the tensile properties of polyurethane before and after modification;

[0031] Figure 10 The comparison of the water resistance of polyurethane before and after modification;

[0032] Figure 11 The variation of the stiffness modulus of polyurethane with temperature before and after modification;

[0033] Figure 12 The variation of the creep rate of polyurethane with temperature before and after modification. Detailed implementation method

[0034] Polyurea is an elastomer formed by the polymerization of amino compounds and isocyanates. Its characteristics are similar to those of polyurethane. It can be divided into aromatic and aliphatic types. It has high reactivity, high ductility and certain mechanical properties. At the same time, it has the characteristics of waterproof, wear-resistant and corrosion-resistant, and the construction temperature and humidity have little influence on it. It has been gradually applied to vehicle and ship anti-corrosion, road traffic protection and other aspects.

[0035] Epoxy resin materials are thermosetting materials themselves, with high strength and good bonding properties, but they are brittle and hard, have poor fluidity at low temperatures, are difficult to operate, and have poor weather resistance, often showing cracking and delamination; Methyl methacrylate (MMA) has good toughness and good low-temperature fluidity, but has low strength, and has a strong pungent smell, toxicity and corrosiveness, and the curing time is less than 1h, which is not conducive to large-area construction; Polyurea has good toughness, but the strength is the lowest and its cost is relatively high, so it is not suitable as a basic raw material. In contrast, polyurethane materials are an elastomer, with relatively high strength, slightly insufficient toughness, but high controllability in the adjustment of curing time and toughness, excellent water resistance and aging resistance, and strong operability for low-temperature construction; Considering comprehensively, the present invention selects polyurethane as the basic raw material and polyurea as the modifier for relevant research.

[0036] Both polyurethane and polyurea belong to two-component adhesives and have similar properties. One of their components is isocyanate. Polyurethane reacts with hydroxyl groups and isocyanates to form urethane groups, while polyurea uses amines as curing agents to react with isocyanates to form urea. The activity of amino groups is higher than that of hydroxyl groups. Therefore, generally speaking, polyurea has a shorter curing time and excellent toughness.

[0037] In the present invention, polyurethane A is a polyester polyol prepolymer, and B is an aromatic isocyanate; polyurea A' is an aliphatic polyurethane prepolymer with excess isocyanate, and B' is a small molecule amine curing agent. The modification principle in the present invention is as follows:

[0038] The following mechanism is used to form a high-performance composite material (adhesive performance) from the two polymers: The amine in polyurea B' reacts with isocyanate to quickly initiate polymerization, and the heat released by the reaction accelerates the complex polymerization between the components. Among them, the urethane groups or urea groups generated by the reaction can further react with isocyanate to form disubstituted polyurea, further extending the chain and topologizing in three-dimensional directions. In the modification scheme, adding 15-20% of polyurea can not only quickly initiate the reaction, shorten the curing time, increase cross-linking, expand the three-dimensional space, and improve adhesion, but also introduce aliphatic polyurea as the soft segment, improving the toughness of the modified polyurethane.

[0039] The principles and characteristics of the present invention are described below in conjunction with examples. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention. For those not specified in the examples, they are carried out under conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0040] The isocyanate in the present invention can be the following materials, but is not limited to the following materials:

[0041] Isophorone diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, toluene diisocyanate or diphenylmethane diisocyanate;

[0042] The high-performance polyurethane-polyurea composite material in the present invention is prepared by the following method: Prepare polyurea and polyurethane separately, then add polyurea according to the dosage to polyurethane, and then stir for 3-5 minutes to obtain it.

[0043] Example 1

[0044] This example provides a high-performance polyurethane-polyurea composite material, including 80-85 wt% of two-component polyurethane and 15-20 wt% of polyurea. The initial curing time of the two-component polyurethane at 25°C is 6.5 h;

[0045] The two-component polyurethane is prepared by the following method: mixing the polyester polyol (Component A) and the isocyanate curing agent (Component B) in a mass ratio of 4:1, mixing and stirring at a speed of 200 rpm for 5 min, and then standing for 2 min.

[0046] The polyurea is polymerized from the amino compound and the isocyanate in a mass ratio of 1:1. The initial curing time at 20 °C is 1.5 h, and the complete curing time is 48 h.

[0047] The solid content of the polyester polyol is not less than 98%, the density is 2.1 g / cm 3 , the viscosity is 2000 mPa·s, the solid content of the isocyanate curing agent is not less than 98%, and the density is 1 g / cm 3 , the viscosity is 3000 mPa·s. The solid content of the polyurea is 100%, the density is 1.0 g / cm 3 , and the viscosity is 2100 mPa·s.

[0048] The high-performance polyurethane-polyurea composite material of this example is prepared by the following method:

[0049] Prepare polyurea and polyurethane separately, then add the polyurea in the dosage to the polyurethane, and then stir for 3 min to obtain it.

[0050] Test Example 1 - Basic Ratio and Optimization of Polyurethane Binder

[0051] Direct tension test: The tensile properties of the adhesive were tested using a universal testing machine. The specific steps are as follows:

[0052] ① Mixing: Mix the polyurethane Components A and B in different ratios and stir for about 3 - 5 minutes at a speed of 200 revolutions / min. After stirring, stand for 1 - 2 min to remove air bubbles.

[0053] ② Specimen casting: Refer to the "Test Method for the Properties of Resin Castings" (GB / T 2567-2008), place the dumbbell-shaped mold on a flat table, apply the release agent, and slowly pour the polyurethane adhesive into the mold to make it self-leveling.

[0054] ③ Curing: Demold after initial curing and cure at room temperature (23 ± 2) °C for 10 d to make it completely cured and the performance stable.

[0055] ④ Conduct the tensile test: Align the specimen with the central axis of the fixture for fixation, the loading speed is 10 mm / min, and record the peak failure load and the deformation amount.

[0056] Table 1 Indexes and Formulas of Tensile Properties

[0057]

[0058] 1.1 Preliminary determination of the dosage of component B of the curing agent

[0059] To determine the specific ratio of components A and B in the polyurethane-based adhesive, the dosage of the curing agent (B / A) was increased from 15% to 35% at an interval gradient of 5%, and the following test design was carried out. To reduce the error of the test results, 3 specimens were prepared for each group during specimen preparation, and the average value of the test results is as follows in the table below.

[0060] Table 2 Influence of the dosage of the curing agent on the tensile properties of polyurethane

[0061]

[0062]

[0063] As can be seen from Table 2 and Figure 1 it can be known that: (1) The curing time gradually decreases as the dosage of the curing agent increases. From the appearance of the formed specimens with each ratio, when the curing agent increases from 15% to 25%, the surface of the specimens is relatively flat, but when the dosage of the curing agent increases to more than 30%, the overall surface of the specimens is no longer flat, and unevenness appears on the surface due to exothermic reaction and gas generation, and the overall shows a brittle and hard state.

[0064] (2) As the dosage of the curing agent continues to increase, the tensile strength of the polyurethane shows a trend of first increasing and then stabilizing. When the curing agent increases from 15% to 25%, the tensile strength increases rapidly. When the dosage of the curing agent is 25%, its tensile strength reaches 12.14 MPa; when the dosage of the curing agent continues to increase, the change in its tensile strength is no longer obvious.

[0065] (3) The elongation at break shows a gradually decreasing trend as the dosage of the curing agent increases. During the process of increasing the dosage of the curing agent from 15% to 35%, the elongation at break almost shows a linear decrease, from 41.87% to 10.23%. After continuing to increase, the change is no longer obvious.

[0066] According to the change trends of the tensile strength and the elongation at break, the dosage of component B of the curing agent is preliminarily set at 20% - 30%.

[0067] 1.2 Specific determination of the dosage of the curing agent

[0068] The dosage of component B of the curing agent was refined, and a tensile test was carried out by gradually increasing it from 23% to 27% at an interval gradient of 1%, as shown in Table 3 below and Figure 2 .

[0069] Table 3 Influence of the dosage of the curing agent on the tensile properties of polyurethane

[0070]

[0071]

[0072] As can be seen from Table 3 and Figure 2 it can be known that when the dosage of curing agent B increases from 23% to 27%, its tensile strength gradually increases and tends to be stable. When the dosage exceeds 25%, the tensile strength remains above 12 MPa and the change is no longer obvious. In contrast, the decrease in elongation at break is obvious. When the dosage of curing agent increases from 23% to 25%, the decrease in elongation at break is 12.35%. When it increases from 25% to 27%, the decrease is 42.76%. The curing time is about 4 h. Considering the elongation at break, tensile strength and curing time comprehensively, the dosage of curing agent is set at 25% as the best.

[0073] 1.3 Influence of molding age on tensile property indexes

[0074] During the test process, it can be found that there is an obvious relationship between the formation of polyurethane strength and the age. For the convenience of later research, the following test scheme is designed. Multiple groups of specimens are molded to study the change trend of tensile property indexes with age, and the specific curing age is determined to provide a curing basis for the related research of colored ultra-thin layer pavement in the later stage. See Table 4 and Figure 3 .

[0075] Table 4 Influence of molding age on tensile properties of polyurethane (curing agent 25%)

[0076]

[0077] As can be seen from Table 4 and Figure 3 it can be seen that the tensile strength shows a linear growth with the extension of curing age. When the curing age reaches the 7th day, its tensile strength is basically fully formed, reaching 12 MPa and no longer increasing with the age. While the elongation at break decreases significantly within the first 5 days of curing and then remains basically stable with the extension of age. Considering both, it can be seen that the performance stable state of the polyurethane adhesive is after the curing age reaches 7 days, which provides a reference for the production and curing time of later specimens.

[0078] To sum up, the present invention studies the component ratios of polyurethane adhesives A and B and the molding age, determines that the dosage of curing agent (B / A) 25% is the best ratio. When the molding age reaches 7 days, the performance is basically stable. At this time, the tensile strength is 12.12 MPa, meeting the design requirements, and the elongation at break is 18.87%, with poor toughness, and it needs to be modified.

[0079] Test Example 2 - Modification Research Based on Tensile Properties

[0080] Since polyurethane itself has poor toughness, polyurea is used to modify polyurethane in this invention. Polyurea is an elastomer formed by the polymerization of amino compounds and isocyanates, and its characteristics are similar to those of polyurethane, having good toughness. Therefore, polyurea and polyurethane can be compounded to improve the toughness of polyurethane. During modification, two adhesives, polyurea and polyurethane, are prepared separately and stirred for 2 - 3 minutes. Then, polyurea is added to polyurethane at different dosages and stirred for another 3 - 5 minutes. After thorough mixing, it is poured into a test mold. After the 7-day curing period, a tensile test is carried out, and the dosage range of polyurea is determined based on the changes in tensile strength and elongation at break, as shown in Table 5.

[0081] Table 5 Influence of polyurea dosage on tensile property indexes

[0082]

[0083] As shown in Table 5 and Figure 4 it can be seen that as the polyurea dosage increases, the tensile strength gradually decreases, and the elongation at break gradually increases. During the change of polyurea dosage from 0% to 20%, the tensile strength has always remained above 6.0 MPa, always meeting the design requirements. When the dosage increases to 15%, the elongation at break increases by nearly 200% and reaches 49.76%, which is greater than the design requirement of 45% for the first time. Therefore, when the polyurea dosage is 15% - 20%, the modification effect is significant.

[0084] Test Example 3 - Modification research based on low-temperature performance

[0085] Currently, there are no relevant technical indicators for the low-temperature performance of resinous binders, and only the low-temperature crack resistance is characterized by the appearance of freeze-thaw tests. However, the performance of polyurethane elastomers is greatly affected by temperature. It shows good toughness at high temperatures. When the temperature decreases, the molecular chains in its curing system are restricted by cross-linking, resulting in limited elongation deformation and rotation, and a significant increase in the stiffness modulus, showing brittle and hard characteristics.

[0086] In this invention, the BBR bending creep stiffness test is used in combination with the "Test Procedures for Bitumen and Bituminous Mixtures in Highway Engineering" (JTG E20 - 2011) to evaluate the low-temperature performance of the modified and unmodified polyurethane binders with the stiffness modulus S and creep rate m as indicators. The larger the stiffness modulus S, the greater the temperature stress generated inside the material and the smaller the strain when the temperature decreases, and the greater the risk of material cracking; the smaller the creep rate m, the weaker the relaxation ability of the material and the worse the low-temperature performance.

[0087] This test example includes the following steps:

[0088] (1) Use polytetrafluoroethylene material to make a test mold according to the size (length × width × height) of 127.00 mm × 6.35 mm × 12.70 mm;

[0089] Place the trial mold on the leveled test plate, brush on the release agent, mix the polyurethane A and B components and polyurea evenly according to different dosages (5% - 20%), then pour them into the mold and let it level automatically. Scrape off the excess with a wooden board, demold after curing at room temperature, and cure for 7 days at room temperature (23 ± 2)°C;

[0090] (2) Conduct the bending rheological test. Before the test, place the small beam specimen in a thermostatic bath under the corresponding test conditions for 60 minutes. Take out the small beam specimen and place it on the bracket of the bending rheometer, then apply a load of 980 mN. During the application of the load, use the displacement sensor in the system to measure the deflection of the small beam specimen, record the creep stiffness modulus and creep rate of the small beam at 60 s to complete the test. Remove the specimen from the bracket for the next test (the bending rheometer needs to be calibrated before the test).

[0091] 3.1 Determination of the dosage of polyurea-modified polyurethane based on low-temperature performance

[0092] Considering the technical requirements of asphalt, prepare small beam specimens of polyurea-modified polyurethane adhesives with different dosages, and conduct tests at different temperature gradients of -24°C, -18°C, -12°C and -6°C respectively. Explore the variation laws of the stiffness modulus S and creep rate m of the polyurethane adhesive with temperature and the variation characteristics before and after modification, and determine the dosage range of polyurea based on this. The test results are shown in Table 6

[0093] Table 6 Summary of bending rheological test data with different polyurea dosages

[0094]

[0095] From Figure 5 、 Figure 6 and Table 6, it can be seen that as the polyurea dosage increases, the stiffness modulus of polyurethane gradually decreases and the creep rate gradually increases at the same temperature, indicating that the low-temperature performance of polyurethane continuously improves with the increase of polyurea dosage. Comparing the curves of the creep rate of polyurethane with temperature at different polyurea dosages, the creep rate changes are small at 5% and 10% dosages, and the two curves are relatively close. However, the creep rate changes significantly when the polyurea dosage increases from 10% to 15%, and the creep rate values at 15% and 20% dosages are generally close. At the same time, taking the requirement that the stiffness modulus is less than 300 MPa at -6°C as the standard, when the polyurea dosage is 15% - 20%, it meets the requirements, and the creep rate in this range exceeds 0.13, showing a significant improvement compared with that before modification.

[0096] Test Example 4 - Modification Research Based on Water Resistance

[0097] The requirements for high strength, high toughness, and low temperature resistance of adhesives ensure the functional performance of colored ultra-thin layer pavements under traffic loads and temperature effects. However, in the face of rain erosion, the shedding and delamination of anti-skid aggregates often occur. Therefore, the high water erosion resistance of adhesives is also the key to the research of colored ultra-thin layer pavements.

[0098] In this test example, combined with the "Technical Guide for Micro-surfacing and Slurry Sealing" (JTGT F40-02-2005), the wet wheel abrasion value was used to explore the water damage resistance of polyurea-modified polyurethane under different dosages, so as to determine the optimal modification scheme for polyurethane. The size of the abrasion value characterizes the attenuation degree of the bonding performance of the binder under immersion in water. The smaller the abrasion value, the smaller the aggregate loss under water immersion conditions, the stronger the water erosion resistance of the adhesive, and the better the water resistance.

[0099] The specific process of this test example is as follows:

[0100] (1) Apply unmodified polyurethane evenly on the felt with a disposable brush. The dosage starts from 0.5 kg / m 2 and increases in a gradient of 0.25 kg / m 2 up to 1.5 kg / m 2 . Spread the anti-skid aggregate (colored ceramsite) evenly on the felt. It is sufficient to be fully covered (after testing, 150 g is used as the spreading standard). After forming, cure at room temperature for 7 days, and conduct a wet wheel abrasion test to determine the effect of the adhesive dosage on the surface of the felt on water resistance.

[0101] (2) Mold wet wheel abrasion specimens with the modified polyurethane under different polyurea dosages at the optimal adhesive dosage. Immerse them for 1 h and 6 d respectively and then conduct wet wheel abrasion tests to evaluate the water resistance of the modified polyurethane at different immersion times, so as to determine the polyurea dosage under different schemes.

[0102] (3) Weigh the mass of the specimen m1 before the test. During the test, it should be noted that the specimen should be completely immersed in water and the water surface height should be not less than 6 mm above the surface of the specimen. After the test, dry the specimen to a constant weight and weigh the mass of the specimen m2 again. Calculate the abrasion value according to Equation 1 and analyze and evaluate its water resistance.

[0103] WTAT=(m1 - m2) / A Equation 1

[0104] Where: WTAT - abrasion value (g / m 2 );

[0105] m1 - mass before abrasion (g);

[0106] m2 - mass after abrasion (g);

[0107] A - abrasion area of the abrasion head rubber tube (0.034 m 2 ).

[0108] 4.1 Determination of water resistance of unmodified polyurethane and amount of adhesive

[0109] Referring to the technical requirements for the water damage resistance performance of microsurfacing, the water damage resistance performance of the unmodified polyurethane adhesive was considered by using the wet wheel abrasion value after 1h immersion to determine the amount of the adhesive, providing a basis for the evaluation of the water resistance of the modified polyurethane.

[0110] Table 7 Results of 1h wet wheel abrasion test of unmodified polyurethane

[0111]

[0112] As Figure 7 shown in and Table 7, the wet wheel abrasion values after 1h immersion under each amount of the unmodified polyurethane adhesive are all less than the technical requirements of the microsurfacing mixture, indicating that the short-term water resistance performance of the polyurethane adhesive is excellent. Among them, when the amount of the adhesive increases from 0.5 kg / m 2 to 0.75 kg / m 2 , the abrasion value shows an obvious decrease from 150.0 g / m 2 to 58.8 g / m 2 . When the amount of the adhesive solution continues to increase, the abrasion value is basically stable between 40 - 60 g / m 2 with little change. Therefore, for the wet wheel abrasion test, the amount of the adhesive is set at 0.75 kg / m 2 . .

[0113] 4.2 Polyurea-modified polyurethane

[0114] Based on the amount of the adhesive being 0.75 kg / m 2 , the short-term and long-term water resistance performances of the modified polyurethane adhesive with different polyurea dosages were evaluated by using the wet wheel abrasion values after 1h and 6d immersion, and compared with the polyurethane before modification to determine the optimal range of the polyurea dosage. The test results are summarized in Table 8.

[0115] Table 8 Results of wet wheel abrasion test of polyurea-modified polyurethane

[0116]

[0117] As Figure 8 shown in and Table 8, by comparing the wet wheel abrasion values after 1h and 6d before and after modification, it can be seen that the long-term water resistance performance of the polyurethane is improved significantly after being modified by polyurea, and the short-term water resistance changes little. However, at the same immersion time, the abrasion values of the specimens show no obvious change with the increase of the polyurea dosage (5% - 20%). Among them, the 1h abrasion value is between 40 - 55 g / m 2 and the 6d abrasion value is between 90 - 110 g / m 2All of them are far less than the required value, also showing excellent water loss resistance performance.

[0118] Based on the above tests, combined with the three important indicators of tensile performance, low-temperature performance, and water resistance, determine the optimal dosage of the modification scheme as shown in Table 9 below and Figures 9 - 12 as follows.

[0119] Table 9 Optimal Dosage Ranges of Two Modification Schemes for Modification Based on Three Properties

[0120]

[0121] To sum up, in the present invention, polyurea is used to modify the toughness of polyurethane based on tensile performance. Finally, it is determined that when the polyurea dosage is 15% - 20%, the modification scheme meets the design requirements.

[0122] Based on the low-temperature performance and the characteristics of polyurethane elastomers, the bending rheology test (BBR) is used to characterize its low-temperature performance. The results show that after modification with polyurea, the low-temperature performance of polyurethane is greatly improved, and the stiffness modulus S at -6°C is less than 300 MPa. Finally, the polyurea dosage is determined to be 15% - 20%.

[0123] Based on the water erosion resistance, the wet wheel abrasion value is used as an index to explore the modification scheme. The results show that the modification improves the water resistance of polyurethane and is far less than the specified requirement value, showing excellent water resistance performance.

[0124] Combined with the three important indicators of tensile performance, low-temperature performance, and water resistance, the optimal modification scheme in the present invention is finally determined to be a polyurea dosage of 15 - 20%.

[0125] Although the specific implementation manners of the present invention have been described in detail, it should not be construed as a limitation on the protection scope of this patent. Within the scope described in the claims, various modifications and deformations that can be made by those skilled in the art without creative labor still fall within the protection scope of this patent.

Claims

1. A high-performance polyurethane-polyurea composite material, characterized in that, It is prepared by polymerizing and modifying polyurea with two-component polyurethane; wherein the dosage of polyurea is 15-20 wt% of two-component polyurethane; The two-component polyurethane is prepared by the following method: mixing polyester polyol and isocyanate curing agent in a mass ratio of 3-5:1, mixing and stirring at a speed of 150-350 rpm for 3-5 min, and standing for 1-2 min. The initial curing time of the two-component polyurethane at 25 °C is 3.5-6.5 h.

2. The high-performance polyurethane-polyurea composite material according to claim 1, characterized in that, The dosage of polyurea is 20 wt% of two-component polyurethane.

3. The high-performance polyurethane-polyurea composite material according to claim 1, wherein, The two-component polyurethane is prepared by the following method: mixing polyester polyol and isocyanate curing agent in a mass ratio of 4:1, mixing and stirring at a speed of 200 rpm for 5 min, and standing for 2 min. The initial curing time of the two-component polyurethane at 25 °C is 6.5 h.

4. The high-performance polyurethane-polyurea composite material according to claim 1, wherein The polyurea is polymerized from amino compound and isocyanate in a mass ratio of 1-2:1-2, the initial curing time at 20 °C is 1.5-2.0 h, and the complete curing time is 45-50 h.

5. The high-performance polyurethane-polyurea composite material according to claim 4, wherein The polyurea is polymerized from amino compound and isocyanate in a mass ratio of 1:1, the initial curing time at 20 °C is 1.5 h, and the complete curing time is 48 h.

6. The preparation method of the high-performance polyurethane-polyurea composite material according to any one of claims 1-5, characterized in that, It includes the following steps: Prepare polyurea and polyurethane separately, then add polyurea into polyurethane according to the dosage, and then stir for 3-5 min to obtain it.

7. Use of the high-performance polyurethane-polyurea composite material according to any one of claims 1-5 in the preparation of epoxy floor paint.

8. Use of the high-performance polyurethane-polyurea composite material according to any one of claims 1-5 in the preparation of road adhesive.

9. Use of the high-performance polyurethane-polyurea composite material according to any one of claims 1-5 in the preparation of thermal insulation board.

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