A bio-based aliphatic polyamine chain extender and a preparation method thereof, a bio-based spray-type flame-retardant polyurea coating and a preparation method and application thereof

Abstract

The application provides a kind of bio-based aliphatic polyamine chain extender and its preparation method, bio-based spray type flame-retardant polyurea coating and its preparation method and application.The polyurea coating of the application, A component includes: polyisocyanate mixture, oligomer polyol, diluent part;Polyisocyanate mixture includes closed PDI;B component includes: amino-terminated polyether, chain extender, silane coupling agent, flame retardant, dispersant, defoamer;Chain extender includes bio-based aliphatic polyamine chain extender N,N'-bis (3-aminopropyl)-1,5-pentanediamine, which can replace traditional expensive triethylene tetramine and isocyanate reaction curing, and provide excellent flexibility and reactivity, with good application development potential.The application introduces PDI and flame retardant, which improves the temperature resistance and weather resistance of the coating, has good flame retardancy, high strength and good toughness, waterproof and corrosion resistant, and can also resist explosion and impact, with superior performance.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurea coatings, and in particular to a bio-based aliphatic polyamine chain extender and a preparation method thereof, a bio-based spray-type flame-retardant polyurea coating and a preparation method and application thereof. Background Art

[0002] A logistics pallet is a horizontal platform device used for the collection, stacking, handling, and transportation of goods and products as unit loads. It serves as a medium for transforming static goods into dynamic ones, acting as a movable loading platform. Pallets have two main functions: 1) They standardize and unitize cargo packaging, protecting the goods and significantly reducing damage and loss. 2) They facilitate handling and loading and unloading, reducing the number of times goods are moved and significantly improving handling and loading and unloading efficiency. Traditional logistics pallets are generally made of metal, plastic, and wood. Wooden pallets are currently the most widely used, but their disadvantages are that they often require epidemic prevention and quarantine during use, and they can also develop knots, splinters, cracks, and deformations, and are prone to mold and mildew in humid environments. Metal pallets are expensive and prone to corrosion. Plastic pallets, on the other hand, have poor aging resistance, become brittle, and have reduced impact strength in low-temperature environments.

[0003] In order to prevent wooden pallets from being infested by insects and mold, it is necessary to apply an anti-corrosion coating to the wooden pallets for corrosion prevention. The existing method of applying anti-corrosion coating to wooden pallets is mainly immersion, that is, pouring the anti-corrosion liquid into a pool, and then soaking the wooden pallet in the pool. However, this method is ineffective for the corrosion prevention of metal pallets and the anti-aging of plastic pallets. The prior art discloses a metal pallet that is easy to move. To prevent electrochemical corrosion of the metal, a rubber pad is bonded to the bottom outer wall of the support block, and the metal plate and the outer wall of the support block are sprayed with an anti-corrosion coating. However, this approach does not have much protective effect on plastic pallets. The prior art also discloses a method for preparing special materials for antioxidant plastic pallets. High-density polyethylene is used as the main raw material. The type and formula of raw materials are optimized. Scientific compounding can significantly improve the impact resistance of plastic pallets and their easy biodegradability, and improve the high temperature resistance, anti-static and anti-shrinkage properties of plastic pallets. However, this method cannot prevent fire, and the coating form has no protective significance for metal pallets and wooden pallets. The prior art also discloses a high-strength waterproof coating for pallets and a preparation method thereof. The coating includes a polyurea prepolymer, a flame-retardant modified polyaspartic acid ester, and graphene oxide. This coating can enhance the impact resistance of the pallet, improve wear resistance and weather resistance, and can also prevent fire. However, due to the high polarity of graphene oxide, it is difficult to disperse evenly in the anti-corrosion coating and cannot effectively block corrosive media. It is also easy to agglomerate with some materials, has poor wettability on the substrate surface, and has weak adsorption force, which can easily cause the coating to fall off. In addition, it is expensive, which limits its scope of use.

[0004] As an excellent elastomer, polyurea exhibits excellent mechanical properties, corrosion resistance, abrasion resistance, and water resistance. It can stably adsorb onto a variety of surfaces, leading to its widespread application in concrete coatings, pipeline corrosion protection, tank linings, automotive coatings, building waterproofing, and even defense applications. Spray polyurea technology, which has subsequently developed in the past decade, is a new high-solids, pollution-free, green construction technology developed abroad to meet environmental protection needs, following in the footsteps of other low-pollution coating technologies such as high-solids coatings, water-based coatings, radiation-cured coatings, and powder coatings. Spray polyurea is an elastomeric coating produced by the rapid reaction of isocyanates and amino compounds. Its tensile strength, tear strength, and weather resistance surpass those of polyurethane waterproofing coatings. It also offers advantages such as rapid curing, ability to be sprayed onto any curved surface, no sagging, moisture insensitivity, and the absence of volatile organic solvents. It can be sprayed onto any substrate, including steel, wood, concrete, and plastic.

[0005] However, polyurea coatings themselves still have some application shortcomings, especially when used on the surface of physical pallets. The sprayed coating is relatively thin and has to withstand the influence of various harsh outdoor transportation conditions. In particular, the adhesion of polyurea coatings to various materials, weather resistance and corrosion resistance, impact resistance to forklifts during use, wear resistance due to friction with the ground, and whether it has better fire retardant properties, etc., are all challenges. The prior art discloses a method for synthesizing polyurea coatings, which uses specially designed polyamino polyethers T-5000, T-403 and D-2000 to achieve the impact strength, flexibility and wear resistance requirements of polyurea materials, but the weather resistance is not good and the flame retardant effect is poor. The prior art discloses a solvent-free polyurea coating, its preparation method and application, component A mainly comprises polyaspartic acid ester resin and aminosilane resin, and component B is an organosilicon resin modified by isocyanate and epoxy, and has better strength and fire resistance, but still poor weather resistance and yellowing resistance. In addition, although spray polyurea technology is a high-solid, pollution-free and environmentally friendly construction technology, the isocyanates used in almost all polyurea materials in the world are mainly derived from petroleum, which has shortcomings in carbon emissions and sustainable development. There is an urgent need to find a new isocyanate raw material with bio-based sources that can replace or partially replace petroleum-based diisocyanates such as hexamethylene diisocyanate (HDI) and diphenylmethane diisocyanate (MDI) to reduce the impact on the global climate environment.

[0006] Based on the defects of current polyurea coatings, it is necessary to improve them. Summary of the Invention

[0007] In view of this, the present invention provides a bio-based aliphatic polyamine chain extender and a preparation method thereof, a bio-based spray-type flame-retardant polyurea coating and a preparation method and application thereof, in order to solve or at least partially solve the defects existing in the prior art.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] In the first aspect, the present invention provides a bio-based aliphatic polyamine chain extender, wherein the bio-based aliphatic polyamine chain extender is N,N'-bis(3-aminopropyl)-1,5-pentanediamine, and its chemical structure is

[0010]

[0011] In a second aspect, the present invention further provides a method for preparing the bio-based aliphatic polyamine chain extender, comprising the following steps:

[0012] Pentamethylenediamine and acrylonitrile undergo Michael addition reaction to produce 1,5-imino-pentamethylenediamine-1,5-dipropionitrile;

[0013] 1,5-imino-pentanediamine-1,5-dipropionitrile is subjected to hydrogenation reaction to obtain N,N'-bis(3-aminopropyl)-1,5-pentanediamine.

[0014] In a third aspect, the present invention further provides a bio-based spray-type flame-retardant polyurea coating, comprising component A and component B; component A comprises the following components in parts by weight: 40 to 110 parts of a polyisocyanate mixture, 10 to 50 parts of an oligomer polyol, and 0 to 5 parts of a diluent;

[0015] The B component comprises the following components by weight: 40-70 parts of amino-terminated polyether, 25-40 parts of chain extender, 2-4 parts of silane coupling agent, 3-5 parts of flame retardant, 1-4 parts of dispersant, and 0-0.5 parts of defoaming agent;

[0016] The chain extender includes the bio-based aliphatic polyamine chain extender.

[0017] Preferably, the polyisocyanate mixture comprises at least one of blocked PDI, HDI, 4,4'-MDI, polymeric MDI, and IPDI.

[0018] Preferably, the polymeric MDI comprises PM400 and / or PM200;

[0019] And / or, the preparation method of the closed PDI is:

[0020] After mixing PDI monomer and organic solvent, the temperature is controlled at 50-55°C, and then a blocking agent is added. The mixture is reacted at 80-85°C until the NCO mass content reaches 10-15%. After removing the organic solvent, blocked PDI is obtained.

[0021] Wherein, the blocking agent is methyl ethyl ketoxime.

[0022] Preferably, the oligomer polyol comprises polyether polyol and / or polyester polyol;

[0023] The polyether polyol includes at least one of polyoxypropylene glycol and polytetramethylene glycol;

[0024] The polyester polyol includes at least one of polyacrylate polyol and polycarbonate diol;

[0025] The molecular weight of the oligomer polyol is 500 to 2000;

[0026] And / or, the diluent includes at least one of o-xylene and ethyl acetate.

[0027] Preferably, the amino-terminated polyether includes at least one of a difunctional amino-terminated polyether and a trifunctional amino-terminated polyether;

[0028] The difunctional amino-terminated polyether includes at least one of D-230 and D-2000;

[0029] The trifunctional amino-terminated polyether includes at least one of T-5000 and T-403;

[0030] And / or, the silane coupling agent is an aminosilane coupling agent;

[0031] And / or, the flame retardant includes at least one of trichloropropyl phosphate, triphenyl phosphate, and 4-aminophenyl phosphate;

[0032] And / or, the dispersant includes at least one of BYK-110 and BYK-161;

[0033] And / or, the defoaming agent includes at least one of a fluorine-modified silicone defoaming agent and an acrylic defoaming agent;

[0034] And / or, the chain extender further comprises at least one of dimethylthiotoluenediamine and diethyltoluenediamine.

[0035] In a fourth aspect, the present invention further provides a method for preparing the bio-based spray-type flame-retardant polyurea coating, comprising the preparation of component A and the preparation of component B;

[0036] The preparation of component A comprises the following steps:

[0037] The oligomer polyol is vacuum dehydrated, and then the polyisocyanate mixture is added and reacted, and then a diluent is added to obtain an isocyanate prepolymer, which is component A;

[0038] The preparation of component B comprises the following steps:

[0039] The amino-terminated polyether, the chain extender, the silane coupling agent, the flame retardant, the dispersant and the defoaming agent are mixed to obtain component B.

[0040] Preferably, the oligomer polyol is vacuum dehydrated, and then the polyisocyanate mixture is added and reacted at a temperature of 115-120° C. and a pressure of 0.2-0.3 MPa for 2-3 hours, and then a diluent is added to obtain an isocyanate prepolymer, which is component A;

[0041] The amino-terminated polyether, chain extender, silane coupling agent, flame retardant, dispersant and defoaming agent are mixed at 80-90° C. for 1-2 hours to obtain component B.

[0042] In a fifth aspect, the present invention also provides an application of the bio-based spray-type flame-retardant polyurea coating or the bio-based spray-type flame-retardant polyurea coating prepared by the preparation method in logistics pallets, storage tank protection, pipeline anti-corrosion, vehicle body protection, building concrete exterior walls, outdoor wooden plank roads, and fences.

[0043] The bio-based aliphatic polyamine chain extender and its preparation method, the bio-based spray-type flame-retardant polyurea coating and its preparation method and application of the present invention have the following beneficial effects compared with the prior art:

[0044] 1. The bio-based aliphatic polyamine chain extender of the present invention, N,N'-bis(3-aminopropyl)-1,5-pentanediamine, can replace the traditional expensive triethylenetetramine (TETA) reaction with isocyanate curing, and provides excellent flexibility and reactivity, with great application development potential. N,N'-bis(3-aminopropyl)-1,5-pentanediamine is synthesized by hydrogenating bio-based pentamethylenediamine and acrylonitrile, and reacts with a compounded polyisocyanate mixture to provide polyurea coatings with excellent toughness and impact resistance.

[0045] 2. Compared with commonly used aromatic polyureas, the bio-based spray-type flame-retardant polyurea coating of the present invention generally has good resistance to UV discoloration and is suitable for outdoor occasions. The present invention introduces a unique bio-based aliphatic pentamethylene diisocyanate monomer (PDI), which is characterized by its low boiling point and viscosity. It provides the overall compounded polyisocyanate mixture with better low-temperature curing performance, reduces the energy consumption caused by rising to higher temperatures during the polyurea coating reaction process, and reduces carbon emissions. At the same time, the pentamethylene diisocyanate monomer (PDI) is combined with isocyanates of other molecular structures with different reactivities. In addition to maintaining the original strength and other properties of the polyurea coating, it also provides higher toughness and elastic impact resistance, making it suitable for the demanding use of logistics pallets.

[0046] 3. In the bio-based spray-type flame-retardant polyurea coating of the present invention, the bio-based pentamethylene diisocyanate monomer (PDI) is capped with a capping agent to reduce its toxicity and volatility, improve storage stability, expand the application range of monomer PDI, and reduce production costs and improve efficiency relative to trimer PDI. In particular, by selecting a suitable capping agent and controlling the unblocking temperature within a certain range, such as by taking advantage of the favorable conditions of the polyurea spraying equipment itself, which requires heating the raw materials to 70-80°C, the capped PDI is unblocked to release the NCO functional groups to participate in the curing reaction, thereby increasing the polyurea reaction speed and further enhancing the surface strength of the coating;

[0047] 4. Currently, logistics pallets are generally not protected by any coatings. Even metal pallets are only coated with traditional anti-rust paint at best, resulting in a high damage rate and a short service life. The polyurea coating developed by this invention can be applied to the surface of logistics pallets made of various materials. It has wider adaptability, better mechanical properties, greater anti-corrosion stability, stronger adaptability in complex service environments, long service life, and excellent comprehensive protection performance.

[0048] 5. Unlike other flame retardant technologies, the flame retardant bio-based polyurea coating provided by the present invention targets pallets made of various materials used in the logistics and transportation sectors. By reacting a selected specific triphenyl phosphate with polyurea and incorporating it into the macromolecular chain, the coating imparts excellent flame retardancy to the polyurea molecule in addition to its inherent self-extinguishing properties. This reduces and controls the negative impact on the mechanical properties of the polyurea material, making it particularly suitable for use in petrochemicals, electrical power distribution, and warehouses and docks where flammable goods are stored, achieving high environmental standards and providing superior safety protection.

[0049] 6. Compared with other polyurea coatings, the special feature of this invention is that it introduces more bio-based raw materials, including bio-based aliphatic pentamethylene diisocyanate monomer (PDI) and bio-based N,N'-bis(3-aminopropyl)-1,5-pentanediamine. The total bio-based content exceeds 20%, which replaces petroleum-based raw materials, significantly reduces carbon emissions, and has a high sustainable environmental advantage. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0051] Figure 1This is a chromatogram of the purified product after hydrogenation of the bio-based aliphatic polyamine chain extender N,N'-bis(3-aminopropyl)-1,5-pentanediamine prepared in Example 1. DETAILED DESCRIPTION

[0052] To make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0053] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0054] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments. In addition, in the description of this application, the term "including" means "including but not limited to". Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be understood as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0055] The present invention provides a bio-based aliphatic polyamine chain extender, which is N,N'-bis(3-aminopropyl)-1,5-pentanediamine, and its chemical structure is

[0056]

[0057] Based on the same invention, the present invention also provides a method for preparing the above-mentioned bio-based aliphatic polyamine chain extender, comprising the following steps:

[0058] Pentamethylenediamine and acrylonitrile undergo Michael addition reaction to produce 1,5-imino-pentamethylenediamine-1,5-dipropionitrile;

[0059] 1,5-imino-pentanediamine-1,5-dipropionitrile is subjected to hydrogenation reaction to obtain N,N'-bis(3-aminopropyl)-1,5-pentanediamine.

[0060] Specifically, the preparation method of N,N'-bis(3-aminopropyl)-1,5-pentanediamine is as follows: using tert-butanol as a solvent, pentamethylenediamine and acrylonitrile are subjected to a Michael addition reaction at a molar ratio of 1:2 (reaction temperature: 80°C, reaction pressure: 0.2 MPa) to produce 1,5-imino-pentamethylenediamine-1,5-dipropionitrile; after separating the solvent by filtration, the final product is introduced into a fixed-bed hydrogenation reactor; the catalyst used is Raney nickel; the reaction pressure is 6.0-7.0 MPa; the hydrogenation product is distilled to obtain N,N'-bis(3-aminopropyl)-1,5-pentamethylenediamine; the measured amine value is 1201, and the viscosity at 20°C is 30 cp. The synthetic chemical reaction formula is:

[0061]

[0062] The bio-based aliphatic polyamine chain extender N,N'-bis(3-aminopropyl)-1,5-pentanediamine, a novel bio-based aliphatic polyamine chain extender, can replace the traditional, expensive triethylenetetramine (TETA) in curing reactions with isocyanates. It offers excellent flexibility and reactivity, and has promising application development potential. N,N'-bis(3-aminopropyl)-1,5-pentanediamine is synthesized by hydrogenating bio-based pentamethylenediamine and acrylonitrile. When reacted with a formulated polyisocyanate mixture, it imparts excellent toughness and impact resistance to polyurea coatings.

[0063] Based on the same inventive concept, the present invention also provides a bio-based spray-type flame-retardant polyurea coating, comprising component A and component B; component A comprises the following components by weight: 40 to 110 parts of a polyisocyanate mixture, 10 to 50 parts of an oligomer polyol, and 0 to 5 parts of a diluent;

[0064] Component B includes the following components by weight: 40-70 parts of amino-terminated polyether, 25-40 parts of chain extender, 2-4 parts of silane coupling agent, 3-5 parts of flame retardant, 1-4 parts of dispersant, and 0-0.5 parts of defoaming agent;

[0065] Chain Extender The bio-based aliphatic polyamine chain extender described above.

[0066] Specifically, the polyurea coating of the present invention consists of component A and component B, wherein the molar ratio of -NCO in component A to -NH in component B is 1:(1.0-1.15); component A is a prepolymer prepared by reacting an isocyanate mixture containing multiple diisocyanates including bio-based aliphatic 1,5-pentamethylene diisocyanate (PDI) with an oligomer polyol.

[0067] In some embodiments, the polyisocyanate mixture includes at least one of blocked PDI, hexamethylene diisocyanate (HDI), diphenylmethane diisocyanate (MDI), diphenylmethane diisocyanate (4,4'-MDI), polymeric MDI, and isophorone diisocyanate (IPDI).

[0068] The preferred polyisocyanate mixture includes 10-20 parts of blocked bio-based 1,5-pentamethylene diisocyanate (PDI) and 30-90 parts of other diisocyanates (i.e., HDI, 4,4'-MDI, polymeric MDI, IPDI, etc.). The present invention specifically incorporates bio-based aliphatic 1,5-pentamethylene diisocyanate (PDI) and a flame retardant to improve the coating's heat and weather resistance while also providing excellent flame retardancy, high strength, good toughness, waterproofness, corrosion resistance, explosion resistance, and impact resistance, resulting in superior performance.

[0069] Specifically, the key isocyanate raw materials used in polyurea coatings and their compounds all contain bio-based aliphatic 1,5-pentamethylene diisocyanate (PDI), also known as pentamethylene diisocyanate. This is a new process for preparing diisocyanates through biomass sources such as corn and straw through bio-enzyme fermentation and chemical synthesis reactions. The biomass content exceeds 70%, which greatly reduces carbon emissions. Moreover, pentamethylene diisocyanate monomer (PDI) is a long-chain aliphatic diisocyanate with good yellowing resistance and weather resistance, and is particularly suitable for industrial fields in some outdoor application scenarios. Bio-based aliphatic 1,5-pentamethylene diisocyanate (PDI), its main raw materials are a new process of preparing biomass raw materials such as corn and straw through bio-enzyme fermentation and chemical synthesis, which replaces petroleum-based raw materials, effectively reduces carbon emissions, and has a high sustainable environmental protection advantage; its production process is as follows:

[0070]

[0071] Compared to commonly used aromatic polyureas, the lower boiling point of 1,5-pentamethylene diisocyanate (PDI) provides the overall polyisocyanate mixture with better low-temperature curing properties, reducing energy consumption and carbon emissions caused by the high temperatures reached during the polyurea coating reaction. Furthermore, the combination of 1,5-pentamethylene diisocyanate (PDI) with other isocyanates of varying reactivity not only maintains the inherent strength of the polyurea coating but also enhances its weathering and yellowing resistance, making it suitable for the demanding environments of logistics pallets.

[0072] In some embodiments, the polymeric MDI includes PM400 and / or PM200; specifically, PM400 is Wanhua WANNATE PM400 polymeric MDI, and PM200 is Wanhua PM20 polymeric MDI.

[0073] In some embodiments, the blocked PDI is prepared by:

[0074] After mixing PDI monomer and organic solvent, the temperature is controlled at 50-55°C, and then a blocking agent is added. The mixture is reacted at 80-85°C until the NCO mass content reaches 10-15%. After removing the organic solvent, blocked PDI is obtained.

[0075] The blocking agent is methyl ethyl ketoxime MEKO, and the organic solvent is propylene glycol methyl ether acetate.

[0076] Monomeric PDI needs to be modified with a blocking agent to partially shield the isocyanate groups and passivate them, while at the same time releasing more isocyanate functional groups at the set deblocking temperature to participate in subsequent reactions. The -NCO mass content is controlled within the range of 10-15%.

[0077] Based on the bio-based aliphatic pentamethylene diisocyanate monomer (PDI), the present invention also discloses an NCO end-capping technology to achieve the purpose of reducing toxicity and extending storage time. At the same time, since the deblocking temperature range of the end-capping agent coincides with the working temperature of the sprayed two-component polyurea, more NCO functional groups participate in the reaction after deblocking, forming a richer chain-extended molecular structure.

[0078] In some embodiments, the oligomeric polyol comprises a polyether polyol and / or a polyester polyol;

[0079] The polyether polyol includes at least one of polyoxypropylene glycol PPG and polytetramethylene glycol PTMEG;

[0080] The polyester polyol includes at least one of polyacrylate polyol and polycarbonate diol;

[0081] The molecular weight of oligomer polyols is 500 to 2000;

[0082] In some embodiments, the diluent includes at least one of o-xylene and ethyl acetate.

[0083] In some embodiments, the amino-terminated polyether includes at least one of a difunctional amino-terminated polyether and a trifunctional amino-terminated polyether;

[0084] The difunctional amino-terminated polyether includes at least one of D-230 and D-2000;

[0085] The trifunctional amino-terminated polyether includes at least one of T-5000 and T-403;

[0086] In some embodiments, the silane coupling agent is an aminosilane coupling agent.

[0087] In some embodiments, the flame retardant includes at least one of trichloropropyl phosphate (TCPP), triphenyl phosphate, and 4-aminophenyl phosphate;

[0088] In some embodiments, the dispersant includes at least one of BYK-110 and BYK-161.

[0089] Specifically, BYK-110 is BYK wetting and dispersing agent BYK-110 from Germany, and BYK-161 is BYK wetting and dispersing agent BYK-161 from Germany.

[0090] In some embodiments, the defoaming agent includes at least one of a fluorine-modified silicone defoaming agent and an acrylic defoaming agent.

[0091] Preferably, the defoaming agent is BYK-066N, which is a German BYK silicone defoaming agent.

[0092] In some embodiments, the chain extender further comprises at least one of dimethylthiotoluenediamine (DMTDA) and diethyltoluenediamine (DETDA).

[0093] In some embodiments, component A includes the following components in parts by weight: 10 to 20 parts of blocked bio-based 1,5-pentamethylene diisocyanate (PDI), and 30 to 70 parts of an isocyanate mixture compounded with other diisocyanates (i.e., HDI, MDI, 4,4'-MDI, polymeric MDI, HDI, IPDI, etc.), 10 to 50 parts of oligomer polyols, and 1 to 5 parts of diluents; specifically, component A includes the following components in parts by weight: 10 to 20 parts of blocked bio-based 1,5-pentamethylene diisocyanate (PDI), and 20 to 40 parts of PM400, 0 to 30 parts of PM200, 0 to 18 parts of MDI, 0 to 20 parts of HDI, 0 to 20 parts of IPDI, 15 to 25 parts of oligomer polyols, and 1 to 5 parts of diluents.

[0094] Specifically, the chemical structural formula of pentamethylene diisocyanate monomer (PDI) is:

[0095]

[0096] The chemical structure of hexamethylene diisocyanate trimer (HDI) is:

[0097]

[0098] The chemical formula of diphenylmethane diisocyanate (4,4'-MDI) is:

[0099]

[0100] The chemical structure of isophorone diisocyanate (IPDI) is:

[0101]

[0102] The chemical structure of polymeric MDI is:

[0103] The chemical formula of the methyl ethyl ketoxime-terminated pentamethylene diisocyanate prepolymer (PDI) in component A is:

[0104] The chemical structure of the amino-terminated polyether D-2000 used in component B is:

[0105]

[0106] The chemical structure of amino-terminated polyether D-230 is:

[0107] The chemical structure of amino-terminated polyether T-5000 is:

[0108]

[0109] The chemical structure of amino-terminated polyether T-403 is:

[0110]

[0111] The chemical formula of the aminosilane coupling agent used in component B is:

[0112]

[0113] The chemical formula of the chain extender diethyltoluenediamine (DETDA) used in component B is:

[0114]

[0115] The chemical formula of the chain extender dimethylthiotoluenediamine (DMTDA) used in component B is:

[0116]

[0117] In order to overcome the lack of an efficient protective coating suitable for various materials on the outer surface of existing logistics pallets, and at the same time to solve the shortcomings of commonly used traditional polyurea coating technology, the present invention is based on a new isocyanate molecular structure such as bio-based aliphatic pentamethylene diisocyanate monomer (PDI) or trimer pentamethylene diisocyanate, and has developed a new type of high-solid, pollution-free logistics pallet polyurea coating and preparation method suitable for various material substrates. This process belongs to a fast-reaction spraying system, A and B two-components, the raw material system has a fast reaction and curing speed, and the process is simple. A 0.2-0.3mm thick coating can be sprayed on the vertical surface and curved surface without falling off. The polyurea coating adopts a one-time coating process, and there is no connection seam. It is a dust-free material polyurea coating with strong adhesion, friction resistance, strong hardness, and certain flame retardant and self-extinguishing functions.

[0118] In a fourth aspect, the present invention further provides a method for preparing the above-mentioned bio-based spray-type flame-retardant polyurea coating, comprising the preparation of component A and the preparation of component B;

[0119] The preparation of component A comprises the following steps:

[0120] The oligomer polyol is vacuum dehydrated, and then the polyisocyanate mixture is added and reacted, and then a diluent is added to obtain an isocyanate prepolymer, which is component A;

[0121] The preparation of component B comprises the following steps:

[0122] The amino-terminated polyether, the chain extender, the silane coupling agent, the flame retardant and the dispersant are mixed to obtain component B.

[0123] In some embodiments, the oligomer polyol is vacuum dehydrated, and then a polyisocyanate mixture is added, and the mixture is reacted at a temperature of 115-120° C. and a pressure of 0.2-0.3 MPa for 2-3 hours, and then a diluent is added to obtain a composite isocyanate prepolymer including pentamethylene diisocyanate (PDI) terminated with MEKO, which is component A.

[0124] The amino-terminated polyether, chain extender, silane coupling agent, flame retardant and dispersant are mixed at 80-90° C. for 1-2 hours to obtain component B.

[0125] Specifically, the preparation method of the bio-based spray-type flame-retardant polyurea coating of the present application comprises the following steps: first, the -NCO functional groups of the monomer bio-based aliphatic pentamethylene diisocyanate monomer (PDI) are partially blocked to obtain a modified pentamethylene diisocyanate monomer (PDI), then one or more of hexamethylene diisocyanate (HDI), diphenylmethane diisocyanate (MDI), polymeric MDI, isophorone diisocyanate (IPDI) and the like are compounded alone or again, then the oligomer polyol is vacuum dehydrated and then gradually added to the modified isocyanate solution compounded to react to prepare component A; one or more of amino-terminated polyether D-2000, T-5000, D-230, T-403 and the like is prepared with amino silane coupling agent, chain extender, flame retardant, dispersant, defoaming agent and the like to prepare component B.

[0126] In use, components A and B are mixed in proportion and quickly sprayed on the substrate to form a coating.

[0127] In the fifth aspect, the present application also provides an application of the above-mentioned bio-based spray-type flame-retardant polyurea coating or the bio-based spray-type flame-retardant polyurea coating prepared by the above-mentioned preparation method in logistics pallets, storage tank protection, pipeline corrosion prevention, vehicle body protection, building concrete outer wall, outdoor wooden trestle, fence.

[0128] The bio-based spray-type flame-retardant polyurea coating of the present invention generally has good ultraviolet light discoloration resistance compared with commonly used aromatic polyureas, and is suitable for outdoor occasions. The present invention introduces a unique bio-based aliphatic pentamethylene diisocyanate monomer (PDI), which is characterized by its low boiling point and viscosity, providing the overall compounded polyisocyanate mixture with better low-temperature curing performance, reducing energy consumption caused by rising to a higher temperature during the polyurea coating reaction process, and reducing carbon emissions. At the same time, the pentamethylene diisocyanate monomer (PDI) is combined with isocyanates of other molecular structures with different activities. In addition to ensuring the original strength and other properties of the polyurea coating, it also provides higher toughness and elastic impact resistance, which is suitable for the harsh scenarios of logistics pallet use. After the NCO functional group of the bio-based pentamethylene diisocyanate monomer (PDI) is capped with a blocking agent, its toxicity and volatility are reduced, the storage stability is improved, the application range of monomer PDI is expanded, and the production cost is reduced and the efficiency is improved compared with the trimer PDI. In particular, by selecting a suitable sealant, the unsealing temperature can be controlled within a certain range. For example, the polyurea spraying equipment itself needs to heat the raw materials to 70-80°C, which is a favorable condition. This promotes the unsealing of the blocked PDI to release the NCO functional group to participate in the curing reaction, thereby increasing the polyurea reaction rate and further enhancing the surface strength of the coating. Currently, logistics pallets are generally not protected by any coatings. Even the metal pallets are only protected by traditional anti-rust paints, so the damage rate is very high and the service life is short. The polyurea coating developed by the present invention can be applied to the surface of logistics pallets of various materials. It has a wider adaptability, better mechanical properties, stronger anti-corrosion stability, stronger adaptability in complex service environments, long service life, and excellent comprehensive protective performance. Unlike other flame retardant technologies, the flame retardant bio-based polyurea coating provided by the present invention targets pallets of various materials used in the logistics and transportation areas. The selected specific triphenyl phosphate and the like react with the polyurea to form a macromolecular chain. In addition to the self-extinguishing properties of the original polyurea molecules themselves, the polyurea coating is given excellent flame retardant properties, while reducing and The negative impact on the mechanical properties of polyurea materials is controlled, and it is particularly suitable for use in scenarios such as petrochemicals, electrical power distribution, and warehouses and docks where flammable goods are stacked. It has high environmental protection standards and safety protection effects. Compared with other polyurea coatings, the special feature of the present invention is that it introduces more bio-based raw materials, including bio-based aliphatic pentamethylene diisocyanate monomer (PDI) and bio-based N,N'-bis(3-aminopropyl)-1,5-pentanediamine. The total bio-based content exceeds 20%, which replaces petroleum-based raw materials, significantly reduces carbon emissions, and has a high sustainable environmental protection advantage.

[0129] The following further illustrates the bio-based aliphatic polyamine chain extender and its preparation method, and the bio-based spray-on flame-retardant polyurea coating and its preparation method, using specific examples. This section further illustrates the present invention with reference to specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the techniques employed in the examples are conventional techniques well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment employed in the present invention are conventional in the art.

[0130] In the following examples, the polyether polyol and / or polyester polyol, polyether amine, curing agent, and chain extender need to be dehydrated in a vacuum environment before use and then sealed and stored.

[0131] In the following examples, polyetheramine D-2000, T-5000, T-403, and D-230 were purchased from Huntsman (Shanghai); PPG-2000 was purchased from Jiangsu Haian Chemical; and PTMEG-1800 was purchased from BASF (Shanghai).

[0132] Example 1

[0133] The embodiment of the present application provides a bio-based aliphatic polyamine chain extender, wherein the bio-based aliphatic polyamine chain extender is N,N'-bis(3-aminopropyl)-1,5-pentanediamine;

[0134] The preparation method of the above-mentioned N,N'-bis(3-aminopropyl)-1,5-pentanediamine comprises the following steps:

[0135] Using tert-butanol as solvent, pentamethylenediamine and acrylonitrile were subjected to Michael addition reaction at a molar ratio of 1:2 (reaction temperature was 80°C, reaction pressure was 0.2 MPa) to generate 1,5-imino-pentamethylenediamine-1,5-dipropionitrile. After the solvent was separated by filtration, the final product was introduced into a fixed-bed hydrogenation reactor. The catalyst used was Raney nickel. The reaction pressure was 6.5 MPa. The hydrogenation product was distilled to obtain N,N'-bis(3-aminopropyl)-1,5-pentamethylenediamine.

[0136] Example 2

[0137] The present invention provides a method for preparing a closed PDI as follows:

[0138] About 76g of PDI monomer and solvent propylene glycol methyl ether acetate were mixed and heated to 55°C. 41g of methyl ethyl ketoxime was added while stirring under nitrogen protection. The temperature was raised to 80°C and the reaction was carried out for 2h until the NCO mass content reached 11%. The solvent was then removed by vacuum distillation to obtain the blocked PDI.

[0139] Example 3

[0140] The embodiment of the present application provides a method for preparing a bio-based spray-type flame-retardant polyurea coating, including the preparation of component A and the preparation of component B;

[0141] The preparation of component A comprises the following steps:

[0142] S1. After mixing 20 g of the blocked PDI prepared in Example 2, 20 g of Wanhua PM400, 30 g of Wanhua PM200, and 20 g of HDI, 20 g of polyether polyol PPG-2000 (i.e., polypropylene glycol PPG-2000, PPG-2000 having been previously dehydrated in a vacuum environment) was added, the mixture was stirred and heated to 120° C., the pressure was 0.20 MPa, and the reaction was carried out for 2 h. The reaction product was then cooled, removed, and the isocyanate prepolymer of component A was obtained, wherein the mass fraction of -NCO was 20%, and the mixture was sealed and stored.

[0143] The preparation of component B comprises the following steps:

[0144] S2. 40 g of polyetheramine D-2000, 20 g of T-5000, 30 g of T-403, 20 g of diethyltoluenediamine (DETDA) and 3 g of N,N'-bis(3-aminopropyl)-1,5-pentanediamine were respectively put into a stirrer and stirred. Then, 2 g of aminosilane coupling agent, 3 g of triphenyl phosphate, 1 g of BYK-110 dispersant and 0.3 g of BYK-066N defoamer were respectively added and mixed evenly. The mixture was heated to 85°C and stirred thoroughly. After reacting for 1 hour, the mixture was cooled and discharged to obtain component B.

[0145] Polyurea Preparation: Polyurea samples were prepared using a high-pressure airless sprayer and a spray gun for rapid film formation on a substrate. Components A and B prepared in Example 3 were injected into their respective material storage tanks and heated to 70°C. The spray gun pressure was set at 80 kPa, and the volume ratio of A to B output was set at 1:1. Spraying was performed to form a polyurea film with a thickness of 0.2-0.3 mm. This polyurea film exhibited good weathering and corrosion resistance, high strength and impact resistance, high adhesion, and moderate flame retardancy.

[0146] Example 4

[0147] The embodiment of the present application provides a method for preparing a bio-based spray-type flame-retardant polyurea coating, including the preparation of component A and the preparation of component B;

[0148] The preparation of component A comprises the following steps:

[0149] S1. After mixing 20 g of the blocked PDI prepared in Example 2 with 40 g of Wanhua PM400, 30 g of Wanhua PM200, and 20 g of IPDI, 15 g of polytetrahydrofuran (PTMEG-1800) (i.e., polytetrahydrofuran ether (PTMEG1800), which has been previously dehydrated in a vacuum environment) was added. The mixture was stirred and heated to 115° C., the pressure was 0.20 MPa, and the reaction was carried out for 2 h. The reaction product was then cooled and removed to obtain the isocyanate prepolymer of component A, wherein the mass fraction of -NCO was 19%, and the mixture was sealed and stored.

[0150] The preparation of component B comprises the following steps:

[0151] S2. 30 g of polyetheramine D-2000, 30 g of T-5000, 30 g of T-403, 10 g of D-230, 18 g of dimethylthiotoluenediamine (DMTDA) and 2 g of N,N'-bis(3-aminopropyl)-1,5-pentanediamine were respectively put into a stirrer and stirred. Then, 2 g of aminosilane coupling agent, 3 g of triphenyl phosphate, 1 g of BYK-110 dispersant and 0.3 g of BYK-066N defoamer were respectively added and mixed evenly. The mixture was heated to 85°C and stirred thoroughly. After reacting for 1 hour, the mixture was cooled and discharged to obtain component B.

[0152] Polyurea Preparation: Polyurea samples were prepared by rapidly spraying a substrate using a high-pressure airless sprayer and a spray gun. Components A and B prepared in Example 4 were injected into their respective material storage tanks and then heated to 70°C. The spray gun pressure was set at 80 kPa, and the volume ratio of A to B output was set at 1:1. Spraying was performed to form a polyurea film with a thickness of 0.2-0.3 mm. This polyurea film exhibited good corrosion resistance, a slightly longer dry-to-air time, a certain degree of flexibility, good wear resistance, and flame retardancy.

[0153] Example 5

[0154] The embodiment of the present application provides a method for preparing a bio-based spray-type flame-retardant polyurea coating, including the preparation of component A and the preparation of component B;

[0155] The preparation of component A comprises the following steps:

[0156] S1, 20g of the blocked PDI prepared in Example 2 and 18g of MDI-100 (i.e. Wanhua MDI-100 (diphenylmethane diisocyanate), 40g Wanhua PM400, and 20g HDI were mixed, and 25g polytetrahydrofuran PTMEG-1800 (i.e., polytetrahydrofuran ether PTMEG1800, PTMEG1800 was pre-dehydrated in a vacuum environment) was added, and the mixture was stirred and heated to 120°C and a pressure of 0.20 MPa. The reaction was carried out for 2h, and then the temperature was lowered and the reaction product was removed to obtain component A isocyanate prepolymer, with a mass fraction of -NCO of 21%, and the mixture was sealed and stored;

[0157] The preparation of component B comprises the following steps:

[0158] S2. 40 g of polyetheramine D-2000, 30 g of T-5000, 30 g of T-403, 20 g of diethyltoluenediamine (DETDA), and 4 g of N,N'-bis(3-aminopropyl)-1,5-pentanediamine were respectively put into a stirrer and stirred. Then, 2 g of aminosilane coupling agent, 3 g of triphenyl phosphate, and 1 g of BYK-110 dispersant were respectively added and mixed evenly. The mixture was heated to 85°C and stirred thoroughly. After reacting for 1 hour, the temperature was lowered and the mixture was discharged to obtain component B.

[0159] Polyurea Preparation: Polyurea samples were prepared using a high-pressure airless sprayer and a spray gun for rapid film formation on a substrate. Components A and B prepared in Example 5 were injected into their respective material storage tanks and then heated to 70°C. The spray gun pressure was set at 80 kPa, and the volume ratio of A to B output was set at 1:1. A polyurea film with a thickness of 0.2 to 0.3 mm was formed. This polyurea film exhibited excellent weathering and corrosion resistance, high adhesion, high strength, and good impact resistance. The coating was also flexible, wear-resistant, and flame-retardant.

[0160] Comparative Example 1

[0161] This comparative example provides a method for preparing a polyurea coating, including the preparation of component A and component B;

[0162] The preparation of component A comprises the following steps:

[0163] S1. Under inert (nitrogen atmosphere) conditions, heat 48g PPG-2000 to 110℃, dehydrate under vacuum pressure for at least 1h until no bubbles are generated, then cool to 55℃ and add 26g MDI-50 (i.e. MDI-50 (diphenylmethane diisocyanate), 26g MDI-100, react at 85°C for 3h to obtain semi-prepolymer A component;

[0164] The preparation of component B comprises the following steps:

[0165] S2. Disperse and stir 41 g of PPG-2000, 22 g of dimethylthiotoluenediamine (DMTDA), 4 g of N,N-dialkyltoluenediamine, 0.5 g of aminosilane coupling agent, and 0.5 g of dibutyltin dilaurate catalyst to obtain component B;

[0166] Polyurea Preparation: Polyurea samples were prepared using a high-pressure airless sprayer and a spray gun. Components A and B, prepared in Example 5, were injected into their respective material storage tanks and heated to 70°C. The spray gun pressure was set at 80 kPa, and the volume ratio of A to B output was set at 1:1. Polyurea films with a thickness of 0.2-0.3 mm were formed.

[0167] Performance Testing

[0168] Figure 1 This is a gas chromatogram of the purified product after hydrogenation of the bio-based aliphatic polyamine chain extender N,N'-bis(3-aminopropyl)-1,5-pentanediamine prepared in Example 1.

[0169] from Figure 1 As can be seen from the figure, after hydrogenation, the mixture generated by the Michael addition reaction of 1,5-pentanediamine and acrylonitrile has only three peaks in the chromatogram. Among them, the long-chain N,N'-bis(3-aminopropyl)-1,5-pentanediamine formed after addition and reduction at both ends has the highest purity, indicating that the conversion rate of the target product is high.

[0170] A polyurea coating was prepared according to the methods of Examples 3 to 5 and Comparative Example 1, and sprayed on the surface of the molded pallet to form a 0.25 mm thick polyurea film coating. The mechanical properties and flame retardant properties of the polyurea film coating were tested and the test results are shown in Table 1 below.

[0171] Table 1 - Properties of polyurea film coatings prepared in different embodiments

[0172]

[0173] Table 1 shows the test results of tensile strength, tear strength, wear resistance, and adhesion of the coatings formed by spraying the polyurea coatings in Examples 3 to 5 and Comparative Example 1 on the surface of molded pallets. As can be seen from this table, the polyurea coatings provided by the present invention (Examples 3 to 5) are prepared by optimizing the ratio of multiple compounded isocyanates, polyetheramines, and chain extenders. In particular, the prepolymer prepared by NCO-terminated aliphatic isocyanate PDI naturally unblocks when the polyurea is sprayed at elevated temperatures, undergoing a multifunctional chain extension and cross-linking reaction with the specially prepared long-chain aliphatic tetraamine N,N'-bis(3-aminopropyl)-1,5-pentanediamine, giving the reaction system excellent flexibility and low-temperature elasticity. Therefore, the tensile strength and elongation at break of the coatings are better than those of traditional polyurea coatings using MDI or aromatic diamines. The compounded isocyanate system compensates for the hardness deficiency of the aliphatic PDI prepolymer alone, while also exhibiting excellent wear resistance, making it particularly suitable for pallet applications. The addition of a certain amount of flame retardant can improve the limiting oxygen index without losing the strength of the coating, and has a certain improvement in fire resistance. However, since the spray polyurea coating protection in this experiment is mainly aimed at molded pallets, and since a release agent E1657, which is a silicone polymer, is used on the surface of the molded pallet, its presence affects the adhesion of the polyurea coating to the surface of the molded pallet. However, according to the chemical industry standard "Technical Specifications for Spray-type Polyurea Protective Material Coating Engineering" (HG / T 20273-2011), the adhesion of polyurea coatings on different material surfaces is required to be >2.5MPa, so the adhesion of the polyurea coatings of the present invention meets the requirements. Among them, Example 4 has the best adhesion performance.

[0174] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A bio-based spray-type flame-retardant polyurea coating, characterized in that: The method comprises component A and component B; the component A comprises the following components in parts by weight: 40 to 110 parts of a polyisocyanate mixture, 10 to 50 parts of an oligomer polyol, and 0 to 5 parts of a diluent; The B component comprises the following components by weight: 40-70 parts of amino-terminated polyether, 25-40 parts of chain extender, 2-4 parts of silane coupling agent, 3-5 parts of flame retardant, 1-4 parts of dispersant, and 0-0.5 parts of defoaming agent; The chain extender is a bio-based aliphatic polyamine chain extender, and the bio-based aliphatic polyamine chain extender is N,N'-bis(3-aminopropyl)-1,5-pentanediamine, and its chemical structure is ; The polyisocyanate mixture includes blocked PDI and at least one of HDI, 4,4'-MDI, polymeric MDI, and IPDI; The preparation method of the closed PDI is: After mixing PDI monomer and organic solvent, the temperature is controlled at 50-55°C, and then a blocking agent is added. The mixture is reacted at 80-85°C until the NCO mass content reaches 10-15%. After removing the organic solvent, blocked PDI is obtained. Wherein, the blocking agent is methyl ethyl ketoxime.

2. The bio-based sprayable flame-retardant polyurea coating according to claim 1, characterized in that: The polymeric MDI comprises PM400 and / or PM200.

3. The bio-based sprayable flame-retardant polyurea coating according to claim 1, wherein: The oligomer polyol includes polyether polyol and / or polyester polyol; The polyether polyol includes at least one of polyoxypropylene glycol and polytetramethylene glycol; The polyester polyol includes at least one of polyacrylate polyol and polycarbonate diol; The molecular weight of the oligomer polyol is 500-2000; And / or, the diluent includes at least one of o-xylene and ethyl acetate.

4. The bio-based sprayable flame-retardant polyurea coating according to claim 1, wherein: The amino-terminated polyether includes at least one of a difunctional amino-terminated polyether and a trifunctional amino-terminated polyether; The difunctional amino-terminated polyether includes at least one of D-230 and D-2000; The trifunctional amino-terminated polyether includes at least one of T-5000 and T-403; And / or, the silane coupling agent is an aminosilane coupling agent; And / or, the flame retardant includes at least one of trichloropropyl phosphate, triphenyl phosphate, and 4-aminophenyl phosphate; And / or, the dispersant includes at least one of BYK-110 and BYK-161; And / or, the defoaming agent includes at least one of a fluorine-modified silicone defoaming agent and an acrylic defoaming agent; And / or, the chain extender further comprises at least one of dimethylthiotoluenediamine and diethyltoluenediamine.

5. A method for preparing a bio-based sprayable flame-retardant polyurea coating according to any one of claims 1 to 4, characterized in that: Including the preparation of component A and the preparation of component B; The preparation of component A comprises the following steps: The oligomer polyol is vacuum dehydrated, and then the polyisocyanate mixture is added and reacted, and then a diluent is added to obtain an isocyanate prepolymer, which is component A; The preparation of component B comprises the following steps: The amino-terminated polyether, chain extender, silane coupling agent, flame retardant, dispersant and defoamer are mixed to obtain component B.

6. The method for preparing the bio-based sprayable flame-retardant polyurea coating according to claim 5, wherein: The oligomer polyol is vacuum dehydrated, and then the polyisocyanate mixture is added and reacted at a temperature of 115-120°C and a pressure of 0.2-0.3 MPa for 2-3 hours. Then a diluent is added to obtain an isocyanate prepolymer, which is component A; The amino-terminated polyether, chain extender, silane coupling agent, flame retardant, dispersant and defoaming agent are mixed at 80-90° C. for 1-2 hours to obtain component B.

7. Use of the bio-based spray-type flame-retardant polyurea coating according to any one of claims 1 to 4 or the bio-based spray-type flame-retardant polyurea coating prepared by the preparation method according to any one of claims 5 to 6 in logistics pallets, storage tank protection, pipeline anti-corrosion, vehicle body protection, building concrete exterior walls, outdoor wooden plank roads, and fences.

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