Aliphatic polyurethane finish paint with high adhesion resistance and preparation method thereof

Abstract

The invention belongs to the field of polymer coatings, and provides an aliphatic polyurethane finish paint with high adhesion resistance and a preparation method thereof. According to the invention, a polyurethane phase and a polyacrylate network are adopted to construct a semi-interpenetrating network structure, cyclic carbonate and hydrolyzable silane end groups are introduced into double-end functionalized polysiloxane, and a silicon-oxygen network surface layer is self-assembled after coating and curing; the high crosslinking density with the gel fraction being greater than or equal to 85%, the wear-resistant and anti-slip performance with the dry friction coefficient being greater than or equal to 0.50 and the abrasion mass loss being less than or equal to 0.030 g / 500 r, the ultra-low surface energy anti-dirt performance with the water contact angle being greater than or equal to 105 degrees and the surface free energy being less than or equal to 22 mN / m and the environment-friendly characteristic that the volatile organic compound content is less than or equal to 50 g / L are achieved; the three technical contradictions of high gel fraction and ultralow surface energy silica surface layer coupling, high hardness wear resistance and high friction coefficient maintenance, and high solid content and low volatility organic compound processing window and nano gradient silica surface layer construction are solved, and the nano gradient silica coating has wide application value in the field of industrial terraces and metal base material coatings.

Description

Technical Field

[0001] This invention relates to the field of polymer coatings, specifically to an aliphatic polyurethane high anti-fouling topcoat and its preparation method. Background Technology

[0002] Industrial flooring, parking lots, and light chemical applications present multi-dimensional and synergistic demands on the anti-fouling, anti-slip, and abrasion-resistant properties of coatings. In dry operating environments, coatings must possess a high dry-state coefficient of friction to ensure the safety of personnel and logistics equipment, while also demanding excellent abrasion resistance to cope with long-term, high-frequency frictional wear, ensuring the coefficient of friction remains stable throughout its service life. Furthermore, industrial environments often involve the risk of contamination from oil, dust, and chemical media. Coating surfaces must employ low surface energy design to achieve dual anti-adhesion capabilities against both water-based and oil-based contaminants, reducing cleaning and maintenance costs and extending service life. Simultaneously, to comply with increasingly stringent environmental regulations, coating systems must achieve excellent film-forming properties and coating adaptability while ensuring high solids content and low volatile organic compound emissions. The synergistic fulfillment of these performance requirements is crucial for improving the overall service performance of industrial flooring coatings, expanding application scenarios, and promoting the advancement of green coating technology. These are key technical issues that urgently need to be addressed in the current polymer coating field.

[0003] To address the aforementioned performance requirements, existing technologies primarily improve performance by increasing the crosslinking density of the polyurethane or acrylate network, introducing nanofillers, or employing fluorine-containing modifications. However, significant shortcomings remain. For example, Chinese Patent CN119614061A discloses a method for preparing and using a waterborne polyurethane-acrylate wear-resistant and anti-corrosion coating. While it enhances wear resistance through structural design, it fails to resolve the coupling contradiction between high crosslinking density and the self-assembly of surface silica-rich layers. Chinese Patent CN109370411A discloses a fluorosilicone polyurethane-modified acrylic resin waterborne industrial coating. Although it achieves low surface energy, the introduction of fluorine-containing components increases cost and environmental risks. Furthermore, the dry-state friction coefficient of high-hardness coatings is often low, making it difficult to meet anti-slip safety requirements. Furthermore, existing technologies for introducing polysiloxanes mostly employ physical blending or single-end grafting, lacking dual-end functionalization designs to simultaneously achieve chemical bonding with the polyurethane matrix, toughening and regulation of the internal network of the coating by cyclic carbonate groups, and the synergistic effect of hydrolysis and condensation of end-group silanes to form a surface silicon-oxygen network. This results in the failure to effectively resolve the contradictions between high gel fraction and high modulus and ultra-low surface energy, high hardness and wear resistance and high dry friction coefficient, as well as the processing of high solids content and low volatile organic compounds and the construction of nano-gradient silicon-oxygen surface layers. Summary of the Invention

[0004] The purpose of this invention is to provide an aliphatic polyurethane high anti-fouling topcoat and its preparation method, which solves the technical pain points of the current waterborne polyurethane acrylate system in terms of coupling contradiction between high gel fraction and high modulus and surface silica enrichment self-assembly to achieve ultra-low surface energy, mechanical and tribological conflict between high hardness and wear resistance and stable maintenance of high dry friction coefficient, and contradiction between the processing window of high solid content and low volatile organic compounds and the reaction diffusion and phase structure control of nanoscale continuous gradient silica surface while maintaining transparent appearance.

[0005] This invention employs a synergistic design approach, constructing a polyurethane phase through a rigid-flexible balance between carbon dioxide-based polycarbonate diol and soybean oil polyol. A hydrophilic chain extender unit is introduced to achieve emulsification stability and ionic crosslinking points. Combined with in-situ semi-continuous emulsion polymerization of acrylate monomers, a high gel fraction polyacrylate network is formed. This semi-interpenetrating network structure synergistically enhances the coating modulus and hardness. Simultaneously, the cyclic carbonate groups of the double-ended functionalized polysiloxane form hydrogen bonds with the carbonyl groups of the polyurethane phase, preventing rapid migration of silicon components. The end-group silanes hydrolyze and condense on the coating surface to construct a nanoscale silicon-oxygen network gradient layer, achieving decoupling between ultra-low surface energy and a high coefficient of friction, significantly surpassing the effect of simple superposition of single systems.

[0006] To achieve the above objectives, the present invention provides the following technical solution: An aliphatic polyurethane high anti-fouling topcoat, comprising: A) The polyurethane phase is formed by the reaction of polyol components with aliphatic diisocyanate and contains 1.5wt%-2.5wt% hydrophilic chain extender units, based on resin solids; B) A polyacrylate network, formed by polymerization of acrylate monomers, forming a semi-interpenetrating network structure with the polyurethane phase, having a gel fraction ≥85 wt%; C) 2.0wt%-5.0wt% of bifunctionalized polysiloxane, based on resin solids, with end groups containing hydrolyzable silane groups SiOR3, where R is methyl or ethyl, and containing cyclic carbonate groups, with a number average functionality of 2.0±0.2, a silicon element mass fraction of 1.2wt%-2.5wt%, and a carbonate group content of 0.20-0.60mmol / g; D) After coating and curing, a silicon-oxygen network surface layer is formed by the hydrolysis and condensation of silane, with a thickness of 20-80 nm; The topcoat, after film formation, has a dry friction coefficient ≥0.50, wear mass loss ≤0.030g under 750g load / 500 rpm, water contact angle ≥105°, n-hexadecane contact angle ≥50°, surface free energy ≤22mN / m, and volatile organic compound content ≤50g / L.

[0007] Furthermore, the polyol component is composed of carbon dioxide-based polycarbonate diol and soybean oil polyol, wherein the hydroxyl value of the carbon dioxide-based polycarbonate diol is 56-120 mgKOH / g, and the hydroxyl value of the soybean oil polyol is 120-220 mgKOH / g. The aliphatic diisocyanate is selected from isophorone diisocyanate, hexamethylene diisocyanate or dicyclohexylmethane diisocyanate; The hydrophilic chain extender unit is derived from dimethylolpropionic acid or dimethylolbutyric acid.

[0008] Furthermore, the acrylate monomer is selected from one or more of butyl acrylate, methyl methacrylate, diethylhexyl acrylate, dihydroxyethyl methacrylate, and dihydroxyethyl acrylate; Optional addition of crosslinking monomers, 0-0.8 wt%, based on the total amount of acrylate monomers; The crosslinking monomer is selected from ethylene glycol dimethacrylate, diethylene glycol diacrylate, or methacryloyloxypropyltriethoxysilane.

[0009] Furthermore, after coating and curing, the silicon atomic fraction of the silicon element on the surface of the silicon-oxygen network is 15at%-30at%, and it exhibits a gradient distribution from 20% to 5% from the surface to a depth of 50nm.

[0010] As a concept of this invention, it employs a triple design: a polyurethane phase and a polyacrylate network to construct a semi-interpenetrating network structure; the introduction of cyclic carbonates and hydrolyzable silane end groups using double-ended functionalized polysiloxanes; and the self-assembly of the silica network surface layer after coating curing. This design primarily enhances the coating's wear resistance, anti-slip properties, ultra-low surface energy anti-fouling properties, and environmentally friendly processing performance. Hydrophilic chain extender units are introduced into the polyurethane phase, forming a stable aqueous emulsion system through carboxyl ionization, reducing the content of volatile organic compounds. Simultaneously, it provides reaction sites and spatial stability for the subsequent semi-continuous emulsion polymerization of acrylate monomers, ensuring the processing window and particle size uniformity of the high-solids system. The polyacrylate network, through high-conversion polymerization and the introduction of optional crosslinking monomers, forms a high-crosslink density rigid skeleton with a gel fraction ≥85%, significantly improving the coating's hardness, modulus, and wear resistance. Furthermore, the semi-interpenetrating network structure generates physical entanglement and hydrogen bonding interactions with the polyurethane phase, preventing increased brittleness caused by high crosslinking. The core innovation of this invention is the design of a dual-terminal functionalized polysiloxane. One end is chemically bonded to the polyurethane backbone via urethane bonds, ensuring no phase separation occurs during emulsion polymerization and film formation. The other end contains hydrolyzable silane groups and cyclic carbonate groups. The former, during the coating curing stage, synergistically hydrolyzes and condenses with the silane used for surface layer construction to form a 20-80 nm thick silicon-oxygen network surface layer, achieving ultra-low surface energy and oil-water repellency with a water contact angle ≥105°, a hexadecane contact angle ≥50°, and a surface free energy ≤22 mN / m. The latter toughens and regulates the internal network of the coating film through the ring-opening and cross-linking reactions of the cyclic carbonate groups, balancing the contradiction between high hardness and high dry friction coefficient. During the coating curing process, the surface-building silanes (tetraethoxysilane and methyltrimethoxysilane) gradually hydrolyze and condense under the action of moisture and catalyst, and synergistically form a nanoscale continuous gradient distribution of silicon-oxygen network surface layer with the end-group silanes of the double-functionalized polysiloxane. The atomic fraction of silicon element gradually decreases from 15%-30% on the surface to 5% at a depth of 50nm, ensuring the uniformity of anti-fouling durability and coating transparency.

[0011] This invention also provides a method for preparing an aliphatic polyurethane high anti-fouling topcoat, comprising the following steps: S1 involves reacting a polyol component with an aliphatic diisocyanate at an NCO / OH molar ratio of 1.6-1.9, adding a hydrophilic chain extender, and reacting at 70-85℃ until the NCO content reaches 2.0wt%-3.0wt%. S2 is adjusted to pH 7.5-8.2 with a neutralizing agent before phase inversion emulsification, controlling the latex particle size D. 50 The wavelength is 80-180nm. S3 was used to complete chain extension by adding a 1.5wt%-2.5wt% aqueous chain extender solution dropwise; S4 was initiated by an initiator at 65-75℃ to carry out semi-continuous emulsion polymerization of acrylate monomers until the gel fraction was ≥85wt% and the residual monomer was <200mg / kg. S5 adjusts the pH of the system to 6.8-7.2, adds double-ended functionalized polysiloxane and silane for surface construction, and after coating and curing, the surface thickness is 20-80nm; S6 when the solid content is 40wt%-50wt% and the particle size D 50 The topcoat was obtained at a wavelength of 80-180 nm.

[0012] Further, in step S1, the polyol components are formulated as follows: 55-75 parts by mass of carbon dioxide-based polycarbonate diol and 25-45 parts by mass of soybean oil polyol. The hydrophilic chain extender is dimethylolpropionic acid or dimethylolbutyric acid, with an amount of 1.5wt%-2.5wt% based on resin solids. The reaction is carried out under a nitrogen or argon protective atmosphere. In step S2, the neutralizing agent is triethylamine, which is added in stages for phase inversion emulsification with water, and the coefficient of variation is ≤0.25. In step S3, the chain extender is ethylenediamine or isophorone diamine, which is added over a dropping time of 30-45 minutes, metered according to an NCO / NH equivalent ratio of 0.95-1.05. After dropping, the mixture is kept warm until the residual NCO content is <0.10wt%.

[0013] Further, the initiator in step S4 is ammonium persulfate, and the acrylate monomer is selected from one or more of butyl acrylate, methyl methacrylate, diethylhexyl acrylate, dihydroxyethyl methacrylate and dihydroxyethyl acrylate. Optionally, 0-0.8 wt% crosslinking monomer is added. Based on the total amount of acrylate monomer, the crosslinking monomer is selected from ethylene glycol dimethacrylate, diethylene glycol diacrylate or methacryloyloxypropyltriethoxysilane, with a conversion rate ≥98 wt%. If necessary, a redox system post-treatment is used.

[0014] Furthermore, the amount of the dual-terminal functionalized polysiloxane used in step S5 is 2.0wt%-5.0wt%, based on resin solids, its end groups contain SiOR3 and can be hydrolyzed and condensed, R is methyl or ethyl, and it contains cyclic carbonate groups, with a number average functionality of 2.0±0.2, a silicon element mass fraction of 1.2wt%-2.5wt%, and a carbonate group content of 0.20-0.60mmol / g; The silane used for the surface layer is tetraethoxysilane and methyltrimethoxysilane, with a total amount of 0.3wt%-1.0wt%, based on resin solids. After coating, it is cured at 25-60℃ and post-cured for 24 hours. The atomic fraction of silicon in the coating surface layer is 15at%-30at%, and it exhibits a gradient distribution of 20% to 5% from the surface to 50nm.

[0015] Furthermore, the dual-terminated functionalized polysiloxane is prepared according to the following steps: A1 raw material formulation: 100 parts by weight of hydroxyl-terminated polydimethylsiloxane, 15-25 parts by weight of propyltriethoxysilane, 10-20 parts by weight of 3-glycidoxypropyltrimethoxysilane, carbon dioxide continuously supplied under conditions of 1.0-2.5 MPa, 5-15 parts by weight of dimethyl carbonate or glycerol carbonate, and 0.1wt%-1.0wt% of tetrabutylammonium bromide or zinc acetate catalyst, based on the total formulation. With the introduction of A2 carbonate end groups, 3-glycidoxypropyltrimethoxysilane is converted into a silane intermediate containing cyclic carbonate end groups at 80-120℃ and under a carbon dioxide atmosphere of 1.0-2.5MPa, or with dimethyl carbonate or glycerol carbonate as the carbon dioxide source, and under the catalysis of tetrabutylammonium bromide or zinc acetate, for 6-12 hours. A3. Uroalkylation and end-group construction: The reaction is carried out at 60-90℃ for 1.5-4.0 hours to react 3-propyltriethoxysilane with hydroxyl-terminated polydimethylsiloxane, controlling the residual isocyanate content to ≤0.20wt%. Subsequently, the product and the intermediate from step A2 are subjected to hydrolysis and condensation under acid catalysis at pH 4.5-5.5 or base catalysis at pH 9.0-10.0 in the presence of trace amounts of water or alcohol. If a blending route is adopted, the anhydrous conditions are maintained to obtain the bifunctionalized polysiloxane product. The A4 endpoint and post-treatment are terminated when the silicon mass fraction is 1.2wt%-2.5wt%, the carbonate group content is 0.20-0.60mmol / g, and the free monomer is ≤200mg / kg. The alcohol is removed under reduced pressure, filtered, and stored in a sealed, water-proof container.

[0016] As another aspect of this invention, a five-step preparation process is employed, consisting of stepwise synthesis, phase inversion emulsification, chain extension, semi-continuous emulsion polymerization, and subsequent addition of silica surface layer building components. This process primarily enhances the system's processing stability, precise control of high gel fraction, and the ordered construction capability of the nano-gradient silica surface layer. Step S1 ensures the polyurethane prepolymer has suitable molecular weight and NCO end-group content by controlling the NCO / OH molar ratio to 1.6-1.9 and precisely metering the hydrophilic chain extender, providing a stable reaction basis for subsequent phase inversion emulsification and chain extension. Step S2 involves adjusting the pH to a weakly alkaline range of 7.5-8.2 using a neutralizing agent before phase inversion emulsification. The carboxyl ionization of the hydrophilic chain extender unit forms a micelle-stabilized system. Segmented water addition controls the coefficient of variation to ≤0.25, achieving a latex particle size D... 50Uniform distribution within the 80-180 nm range reduces the risk of gelation in subsequent polymerization processes and ensures a processing window for the high-solids system. Step S3 employs a chain extender aqueous solution dropwise addition method. By controlling the dropwise addition time and NCO / NH equivalent ratio, the residual NCO content is ensured to be <0.1 wt%, avoiding side reactions between residual NCO and acrylate monomers and interference with the gel fraction. Step S4 utilizes semi-continuous emulsion polymerization technology. By controlling the polymerization temperature at 65-75℃, the type and amount of initiator, and the precise addition of optional crosslinking monomers, a high crosslinking density polyacrylate network with a gel fraction ≥85% and a conversion rate ≥98% is achieved, ensuring residual monomer <200 mg / kg. If necessary, a redox post-treatment system is used to further reduce the residual monomer content, meeting environmental protection requirements and avoiding impact on subsequent coating curing. Step S5 involves adjusting the system pH to a neutral range of 6.8-7.2 before adding bifunctionalized polysiloxane and surface-building silane. This prevents premature hydrolysis and condensation of the silane during the high-temperature emulsion polymerization stage, ensuring the orderly construction of the silicon-oxygen network surface layer during coating curing. After coating, the coating is cured at 25-60℃ and then post-cured for 24 hours. By controlling the curing temperature and humidity, the atomic fraction of silicon in the surface layer is achieved within the range of 15-30 at%, with a continuous gradient distribution of 20%-5% from the surface to a depth of 50 nm, ensuring consistent anti-fouling durability and coating transparency. Step S6 involves controlling the solid content at 40-50 wt% and the particle size D... 50 Within the 80-180nm range, ensure the application performance and storage stability of the topcoat system.

[0017] This invention also provides an application of an aliphatic polyurethane high anti-fouling topcoat in anti-fouling, anti-slip, and wear-resistant coatings for industrial floors and metal substrates. It is suitable for drying workshops, parking lots, and light chemical industries. The dry friction coefficient of the coating is ≥0.50 and the wear mass loss is ≤0.030g / 500 revolutions.

[0018] This invention analyzes the synergistic effect of polyurethane and polyacrylate networks in the semi-interpenetrating network system. The main functions of the polyurethane phase are to provide flexibility, ionic stability introduced by the hydrophilic chain extender units, and chemical bonding sites with the bifunctionalized polysiloxanes. The main chain is formed through the urethane alkylation reaction of polyol components (carbon dioxide-based polycarbonate diol and soybean oil polyol) with aliphatic diisocyanates. The carboxyl ionization of the hydrophilic chain extender units imparts aqueous dispersion stability to the system. Simultaneously, the flexible segments of the polyurethane soft segments provide the coating film with a certain degree of toughness and stress buffering capacity. The main functions of the polyacrylate network are to provide a rigid skeleton with high hardness and high modulus, as well as excellent wear resistance. Through the semi-continuous emulsion polymerization of acrylate monomers (butyl acrylate, methyl methacrylate, etc.) and the introduction of optional crosslinking monomers, a high crosslinking density network with a gel fraction ≥85% is formed, significantly improving the hardness and wear resistance of the coating film. In terms of improving the dry friction coefficient and wear resistance, the polyurethane phase forms a rough structure at the micron to nanoscale on the coating surface through the microphase separation of soft segments, increasing the surface friction. The polyacrylate network resists mechanical loads and rolling wear through a rigid skeleton with high cross-linking density. The two achieve a balance between flexibility and rigidity through the physical entanglement and hydrogen bond interaction of the semi-interpenetrating network structure, avoiding the increase in brittleness and the decrease in dry friction coefficient caused by high cross-linking. In terms of improving anti-fouling performance and surface silica network construction, the polyurethane phase chemically bonds with the urethane bonds of the double-functionalized polysiloxane to ensure that the silica component does not undergo phase separation during emulsion polymerization and film formation. The polyacrylate network provides a stable supporting substrate through a high gel fraction network. Under the synergistic effect of the two, the silane used for surface construction and the end-group silane of the double-functionalized polysiloxane hydrolyze and condense to form a nano-gradient silica network surface during the coating curing stage, achieving ultra-low surface energy and oil-water repellency. At the same time, the cyclic carbonate groups in the double-functionalized polysiloxane toughen and regulate the internal network of the coating film through ring-opening and cross-linking reactions, balancing the contradiction between high hardness and high dry friction coefficient. The synergistic effect of polyurethane phase and polyacrylate network in composite material system is reflected in the fact that the flexibility of polyurethane soft segment and the rigidity of polyacrylate hard segment complement each other through semi-interpenetrating network structure, the ionic stability of hydrophilic chain extender unit ensures the processing window of high solid content system, the dual-terminal functionalized polysiloxane achieves chemical bonding with polyurethane matrix, toughening regulation of cyclic carbonate groups, and surface silicon-oxygen network construction of terminal silane, and the synergistic effect of the three significantly improves the comprehensive performance of coating.

[0019] Beneficial technical effects: 1. Achieving an organic unity between a high gel fraction, highly cross-linked network and an ultra-low surface energy silica surface layer. Through a high cross-linking density design with a polyacrylate network gel fraction ≥85%, chemical bonding between the dual-terminated functionalized polysiloxane and the polyurethane matrix to prevent phase separation, and the synergistic hydrolysis and condensation of silane and end-group silanes during the coating curing stage to form a 20-80nm thick silica network surface layer, the problem of easy phase separation and migration of siloxanes in traditional physical blending methods is solved. This achieves an ultra-low surface energy of ≥105° water contact angle, ≥50° hexadecane contact angle, and ≤22mN / m surface free energy, along with oil-water repellency, significantly improving the coating's anti-fouling durability and self-cleaning ability.

[0020] 2. A mechanical balance between high hardness and wear resistance and a high dry friction coefficient is achieved. This is achieved through a high-crosslink density rigid skeleton of polyacrylate network providing hardness and modulus; micro-phase separation of polyurethane soft segments forming a surface micro-nano rough structure to increase friction; and ring-opening and crosslinking reactions of cyclic carbonate groups in double-ended functionalized polysiloxane to toughen and regulate the internal network of the coating film. This avoids increased brittleness and a decrease in the dry friction coefficient caused by high crosslinking, achieving a dry friction coefficient ≥0.50 and a wear mass loss ≤0.030g under a 750g load / 500 rpm, meeting the safety and durability requirements of industrial floors and parking lots.

[0021] 3. Achieving process compatibility between high solids content, low volatile organic compound (VOC) environmentally friendly processability and precise construction of nano-gradient silica surface layers. This is achieved through the introduction of hydrophilic chain extender units into the polyurethane phase, leading to carboxyl ionization and the formation of a stable aqueous emulsion system. Phase inversion emulsification and chain extension processes are controlled with a coefficient of variation ≤0.25 to ensure particle size uniformity. Furthermore, step S5, after reaching a neutral pH range, adds bifunctionalized polysiloxane and silane for surface construction to prevent premature hydrolysis and condensation. This results in environmentally friendly processability with a solids content of 40-50 wt% and a VOC content ≤50 g / L. Simultaneously, during coating curing, the silicon atomic fraction gradually decreases from 15%-30% at the surface to 5% at a depth of 50 nm, ensuring consistent anti-fouling durability and coating transparency. This expands the application range of the waterborne polyurethane-acrylate composite system in high-performance anti-fouling, anti-slip, and wear-resistant coatings.

[0022] 4. A green chemical design for the immobilization of bio-based raw materials and carbon dioxide was achieved. By using carbon dioxide-based polycarbonate diols and soybean oil polyols as the polyol components, and employing dual-functionalized polysiloxanes, carbon dioxide was continuously supplied as a carbon dioxide source under conditions of 1.0-2.5 MPa during the preparation process. This enabled the chemical immobilization of carbon dioxide and the high-value utilization of bio-based raw materials, reducing dependence on petroleum-based raw materials and aligning with the concepts of green chemistry and sustainable development. Simultaneously, the selection of aliphatic diisocyanates ensured the coating's weather resistance and non-yellowing properties, improving the coating's long-term service performance and appearance retention.

[0023] 5. Achieved multi-functional synergy and adaptability to various application scenarios. Through the synergistic effect of multiple technologies such as semi-interpenetrating network structure, dual-end functional design, and nano-gradient silica surface layer, the topcoat of this invention exhibits excellent comprehensive performance in drying workshops, parking lots, and light chemical environments. It combines a high dry friction coefficient to ensure the safe movement of personnel and vehicles, excellent wear resistance to resist long-term mechanical loads and rolling wear, low surface energy anti-fouling properties to reduce dust and oil adhesion and simplify cleaning and maintenance, and environmentally friendly processability to meet low volatile organic compound emission requirements, providing a new technical solution for anti-fouling, anti-slip, and wear-resistant coatings for industrial floors and metal substrates. Attached Figure Description

[0024] Figure 1 This invention relates to the effect of the amount of hydrophilic chain extender unit on the dry friction coefficient and wear mass loss.

[0025] Figure 2 This invention relates to the effect of the amount of dual-terminated functionalized polysiloxane on the water contact angle and surface free energy.

[0026] Figure 3 This invention relates to the effect of gel fraction on the dry friction coefficient and wear mass loss.

[0027] Figure 4 This invention relates to the effect of the thickness of the silicon-oxygen network surface layer on the water contact angle and the hexadecane contact angle.

[0028] Figure 5 The X-ray photoelectron spectroscopy transmission mode depth profile curves are for Example 1 and Comparative Example 11.

[0029] Figure 6 This is a superimposed DSC comparison curve of Example 1 and Comparative Example 11.

[0030] Figure 7 This is a superimposed comparison of the FTIR (transmission) spectra of Example 1 and Comparative Example 12. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0032] Example 1: This example provides an aliphatic polyurethane high anti-fouling topcoat, comprising a polyurethane phase, a polyacrylate network, a double-ended functionalized polysiloxane, and a silica network surface layer. The polyurethane phase in this example is formed by reacting a polyol component with an aliphatic diisocyanate, containing 2.0 wt% hydrophilic chain extender unit based on resin solids. The polyol component in this example consists of carbon dioxide-based polycarbonate diol and soybean oil polyol, wherein the carbon dioxide-based polycarbonate diol has 65 parts by mass with a hydroxyl value of 88 mg KOH / g, and the soybean oil polyol has 35 parts by mass with a hydroxyl value of 170 mg KOH / g. The aliphatic diisocyanate used in this example is isophorone diisocyanate, and the hydrophilic chain extender unit is derived from dimethylolpropionic acid.

[0033] The polyacrylate network in this embodiment is formed by polymerization of acrylate monomers and forms a semi-interpenetrating network structure with the polyurethane phase of this embodiment, with a gel fraction of 90 wt%. The acrylate monomers used in this embodiment are 45 parts by weight of butyl acrylate, 30 parts by weight of methyl methacrylate, and 25 parts by weight of diethyl methacrylate, with 0.4 wt% crosslinking monomer added. Based on the total amount of acrylate monomers, the crosslinking monomer used in this embodiment is ethylene glycol dimethacrylate.

[0034] In this embodiment, the amount of dual-functionalized polysiloxane used is 3.5 wt%. Based on resin solids, its end groups contain hydrolyzable silane groups SiOR3 (R is ethyl) and cyclic carbonate groups, with a number-average functionality of 2.0, a silicon mass fraction of 1.85 wt%, and a carbonate group content of 0.40 mmol / g. After coating and curing, a siloxane network surface layer formed by the hydrolysis and condensation of silane is constructed, with a thickness of 50 nm. In this embodiment, the dry friction coefficient of the topcoat film is 0.62, the wear mass loss under a 750g load at 500 rpm is 0.018 g, the water contact angle is 112°, the hexadecane contact angle is 58°, the surface free energy is 18.5 mN / m, and the volatile organic compound content is 35 g / L. After coating and curing, the silicon atomic fraction of the siloxane network surface layer in this embodiment is 22.5 at%, and it exhibits a gradient distribution from 20% to 5% from the surface to a depth of 50 nm.

[0035] This embodiment uses the following method for preparation. Step S1: The polyol component is reacted with isophorone diisocyanate at an NCO / OH molar ratio of 1.75. Dimethylolpropionic acid is added as a hydrophilic chain extender at an amount of 2.0 wt% (based on resin solids). The reaction is carried out at 77°C under a nitrogen atmosphere until the NCO content reaches 2.5 wt%. Step S2: Triethylamine is used as a neutralizing agent to adjust the pH to 7.85, followed by staged aqueous phase inversion emulsification, controlling the latex particle size D. 50The wavelength was 130 nm, and the coefficient of variation was 0.18. In step S3, chain elongation was achieved by dropwise addition of a 2.0 wt% ethylenediamine aqueous solution over 38 minutes, metered at an NCO / NH equivalent ratio of 1.00. The mixture was kept at this temperature until the residual NCO content was 0.05 wt%. In step S4, semi-continuous emulsion polymerization of the acrylate monomers was initiated at 70°C using ammonium persulfate as an initiator until a gel fraction of 90 wt% was achieved, with a residual monomer content of 120 mg / kg and a conversion rate of 98.8 wt%.

[0036] Step S5: Adjust the pH of the system to 7.0, add the dual-functionalized polysiloxane and the silane for surface construction. In this embodiment, the silane for surface construction is a mixture of tetraethoxysilane and methyltrimethoxysilane in a mass ratio of 1:1, with a total amount of 0.65 wt% based on resin solids. After coating, it is cured at 43°C and post-cured for 24 hours. The coating surface thickness is 50 nm, and the silicon atomic fraction on the coating surface is 22.5 at%, with a gradient distribution of 20% to 5% from the surface to 50 nm. Step S6: When the solid content is 45 wt% and the particle size D... 50 The topcoat of this embodiment was obtained at 130nm.

[0037] The bifunctionalized polysiloxane of this embodiment is prepared according to the following steps. Step A1: Raw material preparation: 100 parts by weight of hydroxyl-terminated polydimethylsiloxane, 20 parts by weight of 3-propyltriethoxysilane, 15 parts by weight of 3-glycidoxypropyltrimethoxysilane, carbon dioxide continuously supplied at 1.75 MPa, 10 parts by weight of dimethyl carbonate, and 0.5 wt% of tetrabutylammonium bromide catalyst, based on the total formulation. Step A2: Carbonate end group introduction: 3-glycidoxypropyltrimethoxysilane is converted into a silane intermediate containing cyclic carbonate end groups at 100°C and under a carbon dioxide atmosphere of 1.75 MPa, catalyzed by tetrabutylammonium bromide, for 9 hours. Step A3, urethane alkylation and end-group construction, involves reacting 3-propyltriethoxysilane with hydroxyl-terminated polydimethylsiloxane at 75°C for 2.5 hours, controlling the residual isocyanate content to 0.10 wt%. Subsequently, the product of this example is hydrolyzed and condensed with the intermediate from step A2 under acid catalysis conditions (pH 5.0) in the presence of trace amounts of water to obtain the bifunctionalized polysiloxane product. Step A4, endpoint and post-treatment, is terminated when the silicon mass fraction is 1.85 wt%, the carbonate group content is 0.40 mmol / g, and the free monomer content is 115 mg / kg. Alcohols are removed under reduced pressure, the mixture is filtered, and it is sealed and stored in a moisture-proof environment.

[0038] Features of Example 1: This example uses moderate parameter configurations, with all parameters selected within the middle range of the technical solution. The amounts of hydrophilic chain extender (2.0 wt%), dual-terminal functionalized polysiloxane (3.5 wt%), and NCO / OH molar ratio (1.75) are all within the median range, ensuring the stability and reproducibility of the formulation. The 90 wt% gel fraction provides a good network structure, and the 50 nm thickness of the silica network surface layer achieves a balance between surface functionality and substrate adhesion. The combination of a dry-state coefficient of friction of 0.62 and a wear mass loss of 0.018 g after film formation in this example demonstrates excellent anti-slip and wear-resistant performance. The water contact angle of 112° and the n-hexadecane contact angle of 58° indicate good hydrophobicity and oleophobicity, and the VOC content of 35 g / L meets environmental protection requirements. The parameter combination in this example reflects the balance and versatility of the formulation design, making it suitable as a base formulation for a series of products. This example is suitable for conventional applications such as standard industrial flooring, ordinary parking lots, and mild chemical environments. It has moderate requirements for construction conditions, and the curing temperature of 43°C is suitable for room-temperature curing systems, providing a good application window and performance stability.

[0039] Example 2: This example provides an aliphatic polyurethane high anti-fouling topcoat, comprising a polyurethane phase, a polyacrylate network, a double-ended functionalized polysiloxane, and a silica network surface layer. The polyurethane phase in this example is formed by reacting a polyol component with an aliphatic diisocyanate, containing 1.7 wt% hydrophilic chain extender unit based on resin solids. The polyol component in this example consists of carbon dioxide-based polycarbonate diol and soybean oil polyol, wherein 60 parts by weight of the carbon dioxide-based polycarbonate diol has a hydroxyl value of 75 mg KOH / g, and 40 parts by weight of the soybean oil polyol has a hydroxyl value of 150 mg KOH / g. The aliphatic diisocyanate used in this example is hexamethylene diisocyanate, and the hydrophilic chain extender unit is derived from dimethylolpropionic acid.

[0040] The polyacrylate network in this embodiment is formed by polymerization of acrylate monomers and forms a semi-interpenetrating network structure with the polyurethane phase of this embodiment, with a gel fraction of 87 wt%. The acrylate monomers used in this embodiment are 50 parts by weight of butyl acrylate, 35 parts by weight of methyl methacrylate, and 15 parts by weight of diethylhexyl acrylate, with 0.2 wt% crosslinking monomer added. Based on the total amount of acrylate monomers, the crosslinking monomer used in this embodiment is diethylene glycol diacrylate.

[0041] In this embodiment, the amount of dual-functionalized polysiloxane used is 2.5 wt%. Based on resin solids, its end groups contain hydrolyzable silane groups SiOR3 (R is methyl) and cyclic carbonate groups, with a number-average functionality of 1.9, a silicon mass fraction of 1.4 wt%, and a carbonate group content of 0.28 mmol / g. After coating and curing, a silicon-oxygen network surface layer formed by the hydrolysis and condensation of silane is constructed, with a thickness of 35 nm. In this embodiment, the dry-state coefficient of friction after topcoat film formation is 0.58, the wear mass loss under a 750g load at 500 rpm is 0.022 g, the water contact angle is 108°, the hexadecane contact angle is 53°, the surface free energy is 19.8 mN / m, and the volatile organic compound content is 28 g / L. After coating and curing, the silicon atomic fraction of the silicon-oxygen network surface layer in this embodiment is 18 at%, and it exhibits a gradient distribution from 20% to 5% from the surface to a depth of 50 nm.

[0042] This embodiment uses the following method for preparation. Step S1: The polyol component and hexamethylene diisocyanate are reacted at an NCO / OH molar ratio of 1.65. Dimethylolpropionic acid is added as a hydrophilic chain extender at an amount of 1.7 wt% (based on resin solids). The reaction is carried out at 73°C under a nitrogen atmosphere until the NCO content reaches 2.3 wt%. Step S2: Triethylamine is used as a neutralizing agent to adjust the pH to 7.7, followed by staged aqueous phase inversion emulsification, controlling the latex particle size D. 50 The wavelength was 100 nm, and the coefficient of variation was 0.15. In step S3, chain elongation was achieved by dropwise addition of a 1.7 wt% ethylenediamine aqueous solution over 33 minutes, metered at an NCO / NH equivalent ratio of 0.98. The mixture was kept at this temperature until the residual NCO content was 0.06 wt%. In step S4, semi-continuous emulsion polymerization of the acrylate monomers was initiated at 68°C using ammonium persulfate as an initiator until the gel fraction reached 87 wt%, the residual monomer content was 95 mg / kg, and the conversion rate was 98.4 wt%.

[0043] Step S5: Adjust the pH of the system to 6.9, add the dual-functionalized polysiloxane and the silane for surface construction. In this embodiment, the silane for surface construction is a mixture of tetraethoxysilane and methyltrimethoxysilane, with a mass ratio of 2:3 and a total amount of 0.45 wt% based on resin solids. After coating, it is cured at 35°C and post-cured for 24 hours. The coating surface thickness is 35 nm, the silicon atomic fraction of the coating surface is 18 at%, and it exhibits a gradient distribution of 20% to 5% from the surface to 50 nm. Step S6: When the solid content is 42 wt% and the particle size D... 50 The topcoat of this embodiment was obtained at 100nm.

[0044] The bifunctionalized polysiloxane of this embodiment is prepared according to the following steps. Step A1: Raw material preparation: 100 parts by weight of hydroxyl-terminated polydimethylsiloxane, 17 parts by weight of 3-propyltriethoxysilane, 12 parts by weight of 3-glycidoxypropyltrimethoxysilane, carbon dioxide continuously supplied at 1.3 MPa, 7 parts by weight of glycerol carbonate, and 0.3 wt% zinc acetate catalyst, based on the total formulation. Step A2: Carbonate end group introduction: 3-glycidoxypropyltrimethoxysilane is converted into a silane intermediate containing cyclic carbonate end groups at 90°C and under a carbon dioxide atmosphere of 1.3 MPa, catalyzed by zinc acetate, for 7 hours. Step A3, urethane alkylation and end-group construction, involves reacting 3-propyltriethoxysilane with hydroxyl-terminated polydimethylsiloxane at 68°C for 2.0 hours, controlling the residual isocyanate content to 0.08 wt%. Subsequently, the product of this example is hydrolyzed and condensed with the intermediate from step A2 under alkaline catalytic conditions (pH 9.5) in the presence of trace amounts of alcohol to obtain the bifunctionalized polysiloxane product. Step A4, endpoint and post-treatment, is terminated when the silicon mass fraction is 1.4 wt%, the carbonate group content is 0.28 mmol / g, and the free monomer content is 88 mg / kg. Alcohols are removed under reduced pressure, the mixture is filtered, and stored in a sealed, water-proof container.

[0045] Features of Example 2: This example employs conservative parameter configurations, emphasizing formulation stability and cost control. The amount of hydrophilic chain extender (1.7 wt%) is at the lower end of the range, and the amount of bifunctionalized polysiloxane (2.5 wt%) is also relatively low, which helps reduce raw material costs. The gel fraction (87 wt%) is close to the lower limit but still meets performance requirements. The NCO / OH molar ratio (1.65) is relatively low, reducing the use of excess isocyanate. The lower curing temperature (35°C) and the thinner silica network surface layer (35 nm) contribute to energy saving and rapid curing. This example uses hexamethylene diisocyanate, which has better flexibility than isophorone diisocyanate. The addition of 15% diethylhexyl acrylate to the acrylate monomer formulation further improves the flexibility and low-temperature performance of the coating film. The smaller particle size D... 50 A 100nm coating thickness is beneficial for improving the density and gloss of the coating film. The VOC content of 28g / L is the lowest among the four examples, demonstrating its environmental advantages. This embodiment is suitable for cost-sensitive large-area industrial flooring, indoor parking lots, and mild chemical environments. It is particularly suitable for applications requiring flexibility and low-temperature curing, such as cold storage floors and low-temperature workshops. It has a wide application temperature window and is not demanding in terms of ambient temperature.

[0046] Example 3: This example provides an aliphatic polyurethane high anti-fouling topcoat, comprising a polyurethane phase, a polyacrylate network, a double-ended functionalized polysiloxane, and a silica network surface layer. The polyurethane phase in this example is formed by reacting a polyol component with an aliphatic diisocyanate, containing 2.3 wt% hydrophilic chain extender units, based on resin solids. The polyol component in this example consists of carbon dioxide-based polycarbonate diol and soybean oil polyol, wherein the carbon dioxide-based polycarbonate diol has 70 parts by weight with a hydroxyl value of 100 mg KOH / g, and the soybean oil polyol has 30 parts by weight with a hydroxyl value of 190 mg KOH / g. The aliphatic diisocyanate used in this example is dicyclohexylmethane diisocyanate, and the hydrophilic chain extender unit is derived from dimethylolbutyric acid.

[0047] The polyacrylate network in this embodiment is formed by polymerization of acrylate monomers and forms a semi-interpenetrating network structure with the polyurethane phase of this embodiment, with a gel fraction of 93 wt%. The acrylate monomers used in this embodiment are 35 parts by weight of butyl acrylate, 40 parts by weight of methyl methacrylate, 15 parts by weight of diethyl methacrylate, and 10 parts by weight of diethyl methacrylate, with 0.6 wt% crosslinking monomer added. Based on the total amount of acrylate monomers, the crosslinking monomer used in this embodiment is methacryloyloxypropyltriethoxysilane.

[0048] In this embodiment, the amount of dual-terminated functionalized polysiloxane is 4.5 wt%. Based on resin solids, its end groups contain hydrolyzable silane groups SiOR3 (R is ethyl) and cyclic carbonate groups, with a number-average functionality of 2.1, a silicon mass fraction of 2.2 wt%, and a carbonate group content of 0.52 mmol / g. After coating and curing, a silicon-oxygen network surface layer formed by the hydrolysis and condensation of silane is constructed, with a thickness of 65 nm. In this embodiment, the dry-state coefficient of friction after topcoat film formation is 0.68, the wear mass loss under a 750g load at 500 rpm is 0.014 g, the water contact angle is 117°, the hexadecane contact angle is 64°, the surface free energy is 16.8 mN / m, and the volatile organic compound content is 42 g / L. After coating and curing, the silicon atomic fraction of the silicon-oxygen network surface layer in this embodiment is 27 at%, and it exhibits a gradient distribution from 20% to 5% from the surface to a depth of 50 nm.

[0049] This embodiment uses the following method for preparation. Step S1: The polyol component and dicyclohexylmethane diisocyanate are reacted at an NCO / OH molar ratio of 1.85. Dimethylolbutyric acid is added as a hydrophilic chain extender at an amount of 2.3 wt% (based on resin solids). The reaction is carried out at 82°C under an argon protective atmosphere until the NCO content reaches 2.8 wt%. Step S2: Triethylamine is used as a neutralizing agent to adjust the pH to 8.0, followed by staged aqueous phase inversion emulsification, controlling the latex particle size D. 50The wavelength was 160 nm, and the coefficient of variation was 0.22. In step S3, chain elongation was achieved by dropwise addition of a 2.3 wt% isophorone diamine aqueous solution over 42 minutes, metered at an NCO / NH equivalent ratio of 1.03. The mixture was kept at this temperature until the residual NCO content was 0.04 wt%. In step S4, semi-continuous emulsion polymerization of the acrylate monomers was initiated at 73°C using ammonium persulfate as an initiator until a gel fraction of 93 wt% was achieved, with a residual monomer content of 165 mg / kg and a conversion rate of 99.2 wt%. A redox system was used for post-treatment.

[0050] Step S5: Adjust the pH of the system to 7.15, add the dual-functionalized polysiloxane and the silane for surface construction. In this embodiment, the silane for surface construction is a mixture of tetraethoxysilane and methyltrimethoxysilane, with a mass ratio of 3:2 and a total amount of 0.85 wt% based on resin solids. After coating, it is cured at 52°C and post-cured for 24 hours. The coating surface thickness is 65 nm, the silicon atomic fraction of the coating surface is 27 at%, and it shows a gradient distribution of 20% to 5% from the surface to 50 nm. Step S6: When the solid content is 48 wt% and the particle size D... 50 The topcoat of this embodiment was obtained at 160nm.

[0051] The bifunctionalized polysiloxane of this embodiment is prepared according to the following steps. Step A1: Raw material preparation: 100 parts by weight of hydroxyl-terminated polydimethylsiloxane, 23 parts by weight of 3-propyltriethoxysilane, 18 parts by weight of 3-glycidoxypropyltrimethoxysilane, carbon dioxide continuously supplied at 2.2 MPa, 13 parts by weight of dimethyl carbonate, and 0.8 wt% tetrabutylammonium bromide catalyst, based on the total formulation. Step A2: Carbonate end group introduction: 3-glycidoxypropyltrimethoxysilane is converted into a silane intermediate containing cyclic carbonate end groups at 110°C and under a carbon dioxide atmosphere of 2.2 MPa, catalyzed by tetrabutylammonium bromide, for 11 hours. Step A3, urethane alkylation and end-group construction, involves reacting 3-propyltriethoxysilane with hydroxyl-terminated polydimethylsiloxane at 83°C for 3.5 hours, controlling the residual isocyanate content to 0.06 wt%. Subsequently, the product of this example is hydrolyzed and condensed with the intermediate from step A2 under acidic catalytic conditions (pH 4.8) in the presence of trace amounts of water to obtain the bifunctionalized polysiloxane product. Step A4, endpoint and post-treatment, is terminated when the silicon mass fraction is 2.2 wt%, the carbonate group content is 0.52 mmol / g, and the free monomer content is 155 mg / kg. Alcohols are removed under reduced pressure, the mixture is filtered, and then sealed and stored in a moisture-proof environment.

[0052] Features of Example 3: This example employs high-performance parameter configurations, emphasizing superior anti-fouling, anti-slip, and wear-resistant properties. The hydrophilic chain extender dosage of 2.3 wt% is in the upper range, enhancing the hydrophilicity and anti-fouling ability of the coating film. The dosage of the bifunctionalized polysiloxane is relatively high at 4.5 wt%, and the silicon mass fraction of 2.2 wt% and carbonate group content of 0.52 mmol / g are also in the high value range, significantly improving the surface's hydrophobicity, oleophobicity, and self-cleaning properties. The gel fraction of 93 wt% provides a denser network structure, and the relatively high NCO / OH molar ratio of 1.85 ensures cross-linking density. The thicker 65 nm silicon-oxygen network surface layer and the higher silicon atomic fraction of 27 at% form a stronger surface functional layer. This example exhibits the highest dry-state coefficient of friction (0.68) among the four examples, the lowest wear mass loss (0.014 g), and excellent hydrophobic and oleophobic properties with a water contact angle of 117° and a hexadecane contact angle of 64°. The surface free energy (16.8 mN / m) is also the lowest. This embodiment uses dicyclohexylmethane diisocyanate and dimethylolbutyric acid, combined with a high proportion of methyl methacrylate (40%) and added silane crosslinking monomers, to comprehensively improve the hardness, abrasion resistance, and chemical resistance of the coating film. The relatively high curing temperature of 52℃ is beneficial for promoting the full formation of the silicon-oxygen network. This embodiment is suitable for high-performance applications, such as heavy-duty industrial flooring, high-end commercial parking lots, chemical workshops, and food processing plants. It is particularly suitable for harsh environments requiring excellent anti-fouling, anti-slip, and long-term durability, and for occasions with strict requirements for surface cleanliness and coefficient of friction.

[0053] Example 4: This example provides an aliphatic polyurethane high anti-fouling topcoat, comprising a polyurethane phase, a polyacrylate network, a double-ended functionalized polysiloxane, and a silica network surface layer. The polyurethane phase in this example is formed by reacting a polyol component with an aliphatic diisocyanate, containing 1.6 wt% hydrophilic chain extender unit based on resin solids. The polyol component in this example consists of carbon dioxide-based polycarbonate diol and soybean oil polyol, wherein the carbon dioxide-based polycarbonate diol has 57 parts by mass with a hydroxyl value of 62 mg KOH / g, and the soybean oil polyol has 43 parts by mass with a hydroxyl value of 135 mg KOH / g. The aliphatic diisocyanate used in this example is isophorone diisocyanate, and the hydrophilic chain extender unit is derived from dimethylolpropionic acid.

[0054] The polyacrylate network in this embodiment is formed by polymerization of acrylate monomers and forms a semi-interpenetrating network structure with the polyurethane phase of this embodiment, with a gel fraction of 86 wt%. The acrylate monomers used in this embodiment are 42 parts by weight of butyl acrylate, 38 parts by weight of methyl methacrylate, 10 parts by weight of diethylhexyl acrylate, and 10 parts by weight of dihydroxyethyl acrylate, with 0.1 wt% crosslinking monomer added. Based on the total amount of acrylate monomers, the crosslinking monomer used in this embodiment is ethylene glycol dimethacrylate.

[0055] In this embodiment, the amount of dual-functionalized polysiloxane used is 4.8 wt%. Based on resin solids, its end groups contain hydrolyzable silane groups SiOR3 (R is ethyl) and cyclic carbonate groups, with a number-average functionality of 2.2, a silicon mass fraction of 2.4 wt%, and a carbonate group content of 0.24 mmol / g. After coating and curing, a silicon-oxygen network surface layer formed by the hydrolysis and condensation of silane is constructed, with a thickness of 25 nm. In this embodiment, the dry-state coefficient of friction after topcoat film formation is 0.55, the wear mass loss under a 750g load at 500 rpm is 0.025 g, the water contact angle is 110°, the hexadecane contact angle is 56°, the surface free energy is 20.2 mN / m, and the volatile organic compound content is 46 g / L. After coating and curing, the silicon atomic fraction of the silicon-oxygen network surface layer in this embodiment is 16 at%, and it exhibits a gradient distribution from 20% to 5% from the surface to a depth of 50 nm.

[0056] This embodiment uses the following method for preparation. Step S1: The polyol component is reacted with isophorone diisocyanate at an NCO / OH molar ratio of 1.88. Dimethylolpropionic acid is added as a hydrophilic chain extender at an amount of 1.6 wt% (based on resin solids). The reaction is carried out at 84°C under a nitrogen atmosphere until the NCO content reaches 2.1 wt%. Step S2: Triethylamine is used as a neutralizing agent to adjust the pH to 8.1, followed by staged aqueous phase inversion emulsification, controlling the latex particle size D. 50 The wavelength was 90 nm, and the coefficient of variation was 0.12. In step S3, chain elongation was achieved by dropwise addition of a 1.6 wt% ethylenediamine aqueous solution over 31 minutes, metered at an NCO / NH equivalent ratio of 0.96. The mixture was kept at this temperature until the residual NCO content was 0.08 wt%. In step S4, semi-continuous emulsion polymerization of the acrylate monomers was initiated at 66 °C using ammonium persulfate as an initiator until a gel fraction of 86 wt% was achieved, with a residual monomer content of 78 mg / kg and a conversion rate of 98.2 wt%.

[0057] Step S5: Adjust the pH of the system to 7.18, add the dual-functionalized polysiloxane and the silane for surface construction. In this embodiment, the silane for surface construction is a mixture of tetraethoxysilane and methyltrimethoxysilane, with a mass ratio of 1:2 and a total amount of 0.35 wt% based on resin solids. After coating, it is cured at 28°C and post-cured for 24 hours. The coating surface thickness is 25 nm, the silicon atomic fraction of the coating surface is 16 at%, and it exhibits a gradient distribution of 20% to 5% from the surface to 50 nm. Step S6: When the solid content is 41 wt% and the particle size D... 50 The topcoat of this embodiment was obtained at 90nm.

[0058] The bifunctionalized polysiloxane of this embodiment is prepared according to the following steps. Step A1: Raw material preparation: 100 parts by weight of hydroxyl-terminated polydimethylsiloxane, 24 parts by weight of 3-propyltriethoxysilane, 11 parts by weight of 3-glycidoxypropyltrimethoxysilane, carbon dioxide continuously supplied at 2.4 MPa, 6 parts by weight of glycerol carbonate, and 0.2 wt% zinc acetate catalyst, based on the total formulation. Step A2: Carbonate end-group introduction: using glycerol carbonate as the carbonic acid source, under zinc acetate catalysis, at 95°C, 3-glycidoxypropyltrimethoxysilane is converted into a silane intermediate containing cyclic carbonate end-groups, and the reaction is carried out for 8 hours. Step A3, urethane alkylation and end-group construction, involves reacting 3-propyltriethoxysilane with hydroxyl-terminated polydimethylsiloxane at 65°C for 1.8 hours, controlling the residual isocyanate content to 0.15 wt%. The product of this example is then blended with the intermediate from step A2 under anhydrous conditions to obtain the bifunctionalized polysiloxane product. Step A4, endpoint and post-treatment, is terminated when the silicon mass fraction is 2.4 wt%, the carbonate group content is 0.24 mmol / g, and the free monomer content is 68 mg / kg. Alcohols are removed under reduced pressure, followed by filtration and sealing for water-proof storage.

[0059] Example 4 Features: This example uses boundary-validation parameter configurations. The amount of hydrophilic chain extender at 1.6 wt% is close to the lower limit (10%), verifying the feasibility of the formulation with low hydrophilic chain extender content. The amount of bifunctionalized polysiloxane at 4.8 wt% is close to the upper limit (93%), and the silicon elemental mass fraction at 2.4 wt% is also close to the upper limit (92%), verifying the performance of the high silicon content formulation. The gel fraction at 86 wt% just exceeds the lower limit requirement, and the surface thickness at 25 nm is close to the lower limit (8%), verifying the functionality of the thin surface structure. The NCO / OH molar ratio at 1.88 is close to the upper limit (93%), the reaction temperature at 84℃ is close to the upper limit (93%), and the pH value at 8.1 is relatively high (85%). The combination of these parameters demonstrates the stability of the formulation under high NCO ratio, high temperature, and high pH conditions. The solid content at 41 wt% is close to the lower limit (10%), and the particle size D... 50The particle size distribution is 90 nm, close to the lower limit (10%), and the curing temperature is 28°C, close to the lower limit (8%), emphasizing the operability of low solids content, small particle size, and low-temperature curing. In this example, the polyol ratio is 57 parts by mass of carbon dioxide-based polycarbonate diol (close to the lower limit) and 43 parts by mass of soybean oil polyol (close to the upper limit), with hydroxyl values ​​of 62 mg KOH / g and 135 mg KOH / g, respectively, both within the boundary region. The silane content for surface layer construction is 0.35 wt%, close to the lower limit (7%), and the silicon atomic fraction is 16 at%, close to the lower limit (6.7%), further validating the boundary conditions of low silane content and low surface silicon content. This embodiment employs near-boundary parameter combinations in the preparation of dual-functionalized polysiloxanes. 24 parts by mass of 3-propyltriethoxysilane are close to the upper limit (90%), 11 parts by mass of 3-glycidoxypropyltrimethoxysilane are close to the lower limit (10%), CO2 pressure of 2.4 MPa is close to the upper limit (93%), and catalyst dosage of 0.2 wt% is close to the lower limit (11%), verifying the controllability of the product under extreme formulation conditions. This embodiment is suitable for R&D scenarios with stringent requirements for boundary parameter performance verification, providing data support for formulation optimization and process window exploration. It is also suitable for applications under resource-constrained or special construction conditions, such as low-temperature construction, thin-coating systems with special solid content requirements, and high-end applications requiring precise control of surface structure.

[0060] Comparative Example 1: Basically the same as Example 1, except that the content of the hydrophilic chain extender unit is 1.2 wt%, while the amount of other components and preparation conditions remain unchanged.

[0061] Comparative Example 2: It is basically the same as Example 1, except that the content of the hydrophilic chain extender unit is 3.0 wt%, while the amount of other components and preparation conditions remain unchanged.

[0062] Comparative Example 3: Basically the same as Example 1, except that the gel fraction of the polyacrylate network is 78 wt%, which is achieved by reducing the amount of crosslinking monomer to 0.05 wt%, while other conditions remain unchanged.

[0063] Comparative Example 4: It is basically the same as Example 1, except that the amount of double-ended functionalized polysiloxane is 1.5 wt%, while the amount of other components and preparation conditions remain unchanged.

[0064] Comparative Example 5: It is basically the same as Example 1, except that the amount of double-ended functionalized polysiloxane is 5.8 wt%, while the amounts of other components and preparation conditions remain unchanged.

[0065] Comparative Example 6: It is basically the same as Example 1, except that the silicon element mass fraction of the dual-functionalized polysiloxane is 1.0 wt%. This is achieved by adjusting the amount of 3-propylisocyanatetriethoxysilane to 12 parts by mass and the amount of 3-glycidoxypropyltrimethoxysilane to 8 parts by mass in preparation step A1. Other conditions remain unchanged.

[0066] Comparative Example 7: It is basically the same as Example 1, except that the silicon element mass fraction of the dual-functionalized polysiloxane is 2.8 wt%. This is achieved by adjusting the amount of 3-propylisocyanatetriethoxysilane to 28 parts by mass and the amount of 3-glycidoxypropyltrimethoxysilane to 22 parts by mass in preparation step A1, while keeping other conditions unchanged.

[0067] Comparative Example 8: It is basically the same as Example 1, except that the carbonate group content of the bifunctionalized polysiloxane is 0.15 mmol / g, which is achieved by adjusting the reaction time to 4 hours and the reaction temperature to 70°C in preparation step A2, while other conditions remain unchanged.

[0068] Comparative Example 9: Basically the same as Example 1, except that the thickness of the silicon-oxygen network surface layer is 15 nm, which is achieved by reducing the total amount of silane used in the surface layer construction to 0.18 wt%, while other conditions remain unchanged.

[0069] Comparative Example 10: Basically the same as Example 1, except that the thickness of the silicon-oxygen network surface layer is 92nm, which is achieved by increasing the total amount of silane used in the surface layer construction to 1.25wt%, while other conditions remain unchanged.

[0070] Comparative Example 11: Basically the same as Example 1, except that no double-ended functionalized polysiloxane was added, and only the semi-interpenetrating structure of the polyurethane phase and polyacrylate network was retained. The amounts of other components and preparation conditions remained unchanged.

[0071] Comparative Example 12: Basically the same as Example 1, except that no silane for surface construction was added, no silicon-oxygen network surface was formed, and the amounts of other components and preparation conditions remained unchanged.

[0072] Comparative Example 13: It is basically the same as Example 1, except that the amount of crosslinking monomer is 1.2 wt%. Based on the total amount of acrylate monomer, the amount of other components and the preparation conditions remain unchanged.

[0073] Performance testing: Experiment 1: Determination of dry friction coefficient: Test Object: Topcoat film after coating and curing. Test Objective: To evaluate the anti-slip performance of the coating surface and verify whether the dry friction coefficient is ≥0.50. Test Principle: Based on the principle of solid surface tribology, the static friction coefficient is calculated by measuring the ratio of frictional force to normal force when a standard slider slides on the coating surface. Experimental Method: The topcoat is applied to a clean metal or concrete substrate with a coverage rate of 150-200 g / m², and tested after 24 hours of curing. A friction coefficient measuring instrument is used, employing a standard rubber slider (Shore A hardness 60±5). A vertical load of 500 g is applied, and the slider is pulled at a uniform speed of 10 mm / s. The maximum static friction force is recorded, and the friction coefficient is calculated. Five different locations are tested for each sample, and the mean ± standard deviation is taken. Key Parameters: Test temperature 23±2℃, relative humidity 50±10%RH, slider contact area 4 cm². 2 The sliding distance is ≥50mm. Data processing: the coefficient of friction μ=F / N, where F is the maximum static friction force, N is the normal force, n≥5, and the report is the mean ± standard deviation.

[0074] Experiment 2: Abrasion resistance test: Test Object: Topcoat film after coating and curing. Test Objective: To evaluate the abrasion resistance of the coating film and determine whether the abrasion mass loss under a 750g load at 500 revolutions is ≤0.030g. Test Principle: Using a rotary friction and wear tester, a standard grinding wheel is used to wear the coating surface under a specified load and number of revolutions. The mass loss is determined by weighing. Experimental Method: A Taber abrasion tester equipped with a CS-10 standard grinding wheel is used. After the coating film is cured, it is conditioned for 48 hours at 23±2℃ and 50±10%RH. A load of 750g is applied, the rotation speed is 60rpm, and after 500 revolutions, abrasion debris is removed with a soft brush, and the film is weighed using a precision balance (accuracy 0.0001g). The abrasion mass loss is calculated. Three parallel specimens are prepared for each sample. Standard Basis: GB / T1768-2006 "Determination of Abrasion Resistance of Paints and Varnishes - Rotating Rubber Grinding Wheel Method". Key parameters: Load 750±10g, rotation speed 500±5 rpm, grinding wheel specification CS-10, replacement cycle every 500 rpm. Data processing: Wear mass loss Δm=m0-m1 (m0 is the mass before the test, m1 is the mass after the test), n=3, report the average value ± standard deviation.

[0075] Experiment 3: Measurement of water contact angle and n-hexadecane contact angle: Test Object: The surface of the topcoat film after coating and curing. Test Purpose: To evaluate the hydrophobic and oleophobic properties of the coating film, and to determine whether the water contact angle is ≥105° and the hexadecane contact angle is ≥50°. Test Principle: Based on the wetting behavior of droplets on a solid surface, the droplet profile is captured by an optical contact angle meter, and the contact angle is calculated using the Young-Laplace equation. Experimental Method: After the coating film is cured and post-cured for 24 hours, it is placed in an environment of 23±2℃ and relative humidity <30%RH for 2 hours. Using a contact angle meter, ultrapure water (resistivity ≥18.2MΩ·cm) and hexadecane (purity ≥99%) are used as test liquids, respectively. The seated drop method is used, with a droplet volume of 2.0±0.2μL. Measurement is completed within 10 seconds after droplet drop. Five different locations are tested for each sample, and the average contact angle of the left and right sides is taken. Key Parameters: Droplet volume 2μL, measurement time 10s, ambient humidity <30%RH, temperature 23±2℃. Data processing: The contact angle θ was calculated using the ellipse fitting method, n≥5, and the mean ± standard deviation was reported.

[0076] Experiment 4: Surface Free Energy Measurement Test Object: The surface of the topcoat film after coating and curing. Test Objective: To evaluate the surface energy characteristics of the coating film and verify whether the surface free energy is ≤22 mN / m. Test Principle: The Owens-Wendt-Rabel-Kaelble (OWRK) two-liquid method is used. The polar and dispersive components of the surface free energy are calculated by measuring the contact angle between water and diiodomethane. Experimental Method: Immediately after the contact angle measurement, the contact angle of diiodomethane (purity ≥99%, dispersive liquid) is measured. The OWRK model is used, according to the formula γ... s =γ s d +γ s p Through water (γ1=72.8mN / m, γ1) d =21.8mN / m, γ1 p =51.0mN / m) and diiodomethane (γ1=50.8mN / m, γ1 d =50.8mN / m, γ1 p The surface free energy was calculated by simultaneously solving the Young's equation and the geometric mean method equation using contact angle data (γ = 0 mN / m). Five locations were tested for each sample. Key parameters: test liquid purity ≥ 99%, droplet volume 2 μL, ambient temperature 23 ± 2℃, humidity < 30% RH. Data processing: γ was calculated by fitting the equation. s d and γ s p Calculate the total surface free energy γ s For n≥5, report the mean ± standard deviation.

[0077] Experiment 5: Determination of Volatile Organic Compound (VOC) Content: Test Subject: Topcoat (liquid). Test Objective: To determine the content of volatile organic compounds (VOCs) in the coating and verify whether it is ≤50g / L. Test Principle: The total amount of organic compounds with a boiling point ≤250℃ in the coating is determined by gas chromatography (GC) or vacuum distillation. The VOC content is calculated after deducting water and exempted solvents. Experimental Method: Take approximately 2g of uniformly mixed coating sample (accurate to 0.001g), and use a gas chromatograph equipped with a flame ionization detector (FID). The chromatographic column is DB-624 (30m×0.32mm×1.8μm), the injection port temperature is 200℃, the detector temperature is 250℃, the carrier gas is nitrogen (purity ≥99.999%), and the flow rate is 1.2mL / min. Temperature Program: Initial temperature 40℃, hold for 5min, increase to 200℃ at 10℃ / min, and hold for 10min. Quantification is performed using the internal standard method, with n-hexadecane as the internal standard. The determination is performed in triplicate. GB / T 23985-2009 "Determination of Volatile Organic Compounds (VOCs) Content in Paints and Varnishes - Difference Method". Key parameters: Injection volume 1 μL, split ratio 10:1, detection limit 5 mg / kg. Data processing: VOC content (g / L) = (m voc ×ρ) / m sample, where ρ is the coating density, n=3, report the mean ± standard deviation.

[0078] Experiment 6: Determination of gel fraction: Test Subject: Polyacrylate network component. Test Objective: To evaluate the degree of network cross-linking and verify whether the gel fraction is ≥85wt%. Test Principle: The uncross-linked soluble component is extracted using a good solvent via Soxhlet extraction. After drying, the insoluble gel mass fraction is calculated by weighing. Experimental Method: Approximately 0.2g of dried coated sample (accurate to 0.0001g, denoted as m0) is wrapped in a 200-mesh stainless steel filter bag and placed in a Soxhlet extractor. Tetrahydrofuran (THF, purity ≥99.5%) is used as the extractant, and extraction is carried out by reflux for 24 hours (reflux rate approximately 6 times / h). After extraction, the filter bag is removed, and the sample is vacuum dried at 60℃ to constant weight (mass change <0.5mg / h). After cooling, the sample is weighed (denoted as m1). Each sample is tested in triplicate. Key Parameters: Extraction temperature 66℃ (THF boiling point), extraction time 24h, drying temperature 60℃, vacuum degree <0.1kPa. Data processing: Gel fraction G = (m1 / m0) × 100%, n = 3, report mean ± standard deviation.

[0079] Figure 1The effect of the amount of hydrophilic chain extender unit on the dry friction coefficient and wear mass loss was investigated. The fixed parameters were: polyol composition ratio: 65 parts by mass of carbon dioxide-based polycarbonate diol, 35 parts by mass of soybean oil polyol, NCO / OH molar ratio of 1.75, acrylate monomer formulation: 45 parts by mass of butyl acrylate, 30 parts by mass of methyl methacrylate, 25 parts by mass of dihydroxyethyl methacrylate, crosslinking monomer dosage of 0.4 wt%, bifunctionalized polysiloxane dosage of 3.5 wt%, total silane for surface construction of 0.65 wt%, reaction temperature of 77℃, and curing temperature of 43℃. The variable parameter was the amount of hydrophilic chain extender unit from 1.0 wt% to 3.0 wt%. When the amount of hydrophilic chain extender unit is 2.0 to 2.3 wt%, the dry friction coefficient reaches a peak of 0.62 to 0.64 and the wear mass loss is as low as 0.016 to 0.018 g / 500 rpm. When the amount is less than 1.5 wt%, the latex particle instability is insufficient, which leads to an increase in coating surface defects, causing the dry friction coefficient to drop to 0.48 to 0.52 and the wear mass loss to rise to 0.030 to 0.035 g / 500 rpm. When the amount is higher than 2.5 wt%, the water absorption of the coating film is enhanced, which in turn reduces the friction coefficient to 0.54 to 0.60 and the wear mass loss to rise to 0.020 to 0.026 g / 500 rpm. This proves that the optimization of the amount of hydrophilic chain extender unit plays a decisive role in the surface charge stability of latex particles and the uniformity of the microstructure of the coating surface.

[0080] Figure 2 The effect of the amount of dual-functionalized polysiloxane on the water contact angle and surface free energy was investigated. The fixed parameters were: polyol composition ratio 65 parts by mass of carbon dioxide-based polycarbonate diol, 35 parts by mass of soybean oil polyol, 2.0 wt% of hydrophilic chain extender unit, NCO / OH molar ratio 1.75, acrylate monomer formulation 45 parts by mass of butyl acrylate, 30 parts by mass of methyl methacrylate, 25 parts by mass of dihydroxyethyl methacrylate, 0.4 wt% of crosslinking monomer, 0.65 wt% of total silane for surface construction, reaction temperature 77℃, and curing temperature 43℃. The variable parameters were: the amount of dual-functionalized polysiloxane ranging from 1.2 wt% to 6.0 wt%. When the amount of bifunctionalized polysiloxane is 3.5 to 4.5 wt%, the water contact angle reaches 112 to 115° and the surface free energy decreases to 17.2 to 18.5 mN / m, achieving an optimal balance between hydrophobicity and low surface energy. When the amount is less than 2.0 wt%, the surface silicon-oxygen network coverage is insufficient, resulting in a water contact angle of only 106° and a surface free energy of 21.5 mN / m, which limits the hydrophobic performance. When the amount is greater than 5.0 wt%, although the water contact angle further increases to 116 to 118° and the surface free energy decreases to 16.5 to 17.0 mN / m, the performance increase slows down and the cost increases significantly. This indicates that optimizing the amount of bifunctionalized polysiloxane has a key impact on the density of the surface silicon-oxygen network and the construction efficiency of the low surface energy layer.

[0081] Figure 3 The effect of gel fraction on the dry friction coefficient and wear mass loss was investigated. The fixed parameters were: polyol composition ratio: 65 parts by mass of carbon dioxide-based polycarbonate diol, 35 parts by mass of soybean oil polyol, 2.0 wt% of hydrophilic chain extender unit, NCO / OH molar ratio of 1.75, acrylate monomer formulation: 45 parts by mass of butyl acrylate, 30 parts by mass of methyl methacrylate, 25 parts by mass of dihydroxyethyl methacrylate, 3.5 wt% of double-ended functionalized polysiloxane, 0.65 wt% of total silane for surface construction, reaction temperature of 77℃, and curing temperature of 43℃. The variable parameter was the gel fraction, which was adjusted from 75 wt% to 98 wt% by adjusting the amount of crosslinking monomer. When the gel fraction is 88 to 93 wt%, the dry friction coefficient reaches the optimal value of 0.60 to 0.64, and the wear mass loss is as low as 0.015 to 0.019 g / 500 rpm. When the gel fraction is below 85 wt%, the insufficient network crosslinking density leads to a significant decrease in the mechanical strength and wear resistance of the coating film, causing the dry friction coefficient to drop to 0.48 to 0.52 and the wear mass loss to rise to 0.030 to 0.036 g / 500 rpm. When the gel fraction is above 95 wt%, the coating film becomes more brittle, which in turn reduces the friction coefficient to 0.54 to 0.60 and the wear mass loss to rise to 0.019 to 0.024 g / 500 rpm. This demonstrates that the optimization of the gel fraction plays a decisive role in the balance of the three-dimensional crosslinking network density and the surface elastic modulus of the coating film.

[0082] Figure 4 The effect of the thickness of the silica network surface layer on the water contact angle and the hexadecane contact angle was investigated. The fixed parameters were: polyol composition ratio 65 parts by mass of carbon dioxide-based polycarbonate diol, 35 parts by mass of soybean oil polyol, 2.0 wt% of hydrophilic chain extender unit, NCO / OH molar ratio 1.75, acrylate monomer formulation 45 parts by mass of butyl acrylate, 30 parts by mass of methyl methacrylate, 25 parts by mass of dihydroxyethyl methacrylate, 0.4 wt% of crosslinking monomer, 3.5 wt% of double-ended functionalized polysiloxane, reaction temperature 77℃, and curing temperature 43℃. The variable parameter was the silica network surface layer thickness, which was adjusted from 12 nm to 95 nm by adjusting the total amount of silane used in the surface layer construction. When the surface layer thickness of the silicon-oxygen network is 45 to 65 nm, the water contact angle reaches 110 to 114° and the hexadecane contact angle reaches 56 to 62°, achieving the optimal combination of hydrophobic and oleophobic properties. When the surface layer thickness is less than 20 nm, the incomplete coverage of the silicon-oxygen network results in a water contact angle of only 102° and a hexadecane contact angle of only 48°, limiting the hydrophobic and oleophobic properties. When the surface layer thickness is greater than 80 nm, although the water contact angle further increases to 116 to 118° and the hexadecane contact angle increases to 64 to 66°, the performance increase slows down and may affect the transparency and adhesion of the coating. This indicates that the optimization of the surface layer thickness of the silicon-oxygen network has a key impact on the continuity of the surface low-energy layer and the balance of the interfacial bonding force with the substrate.

[0083] Figure 5The X-ray photoelectron spectroscopy transmission mode depth profiles for Example 1 and Comparative Example 11 are shown. The parameters were fixed as follows: measurement mode: transmission; depth range: 0–50 nm; step size: 2 nm; X-axis: depth (nm); Y-axis: elemental atomic fraction (at%); elemental data: three superimposed curves for Si / C / O; data were quantitatively normalized to 100 at% based on Si 2p, O 1s, and C 1s; instrument sputtering equivalent rate: 0.5 nm·s. -1 The variable parameters were whether the sample system contained bifunctionalized polysiloxanes and a surface silicon-oxygen network (Example 1 contained them, Comparative Example 11 did not). In Example 1, the Si atomic fraction decreased from approximately 22.5 at% to approximately 5 at% within the range of 0–50 nm, with O changing in the same direction as Si while C was a supplement. In Comparative Example 11, Si was only about 2–2.5 at% and the change with depth was gradual. The conclusion is that the bifunctionalized polysiloxanes and the semi-interpenetrating network synergistically induce the formation of a nanoscale silicon-oxygen surface gradient, significantly enhancing the enrichment of surface Si and achieving controlled decay within 50 nm.

[0084] Figure 6 The above is a superimposed DSC comparison curve of Example 1 and Comparative Example 11. The fixed parameters are: heating rate 10 ℃ / min, temperature range -60 to 120 ℃, step size 0.5 ℃, ΔH0 reference enthalpy 100 J / g, Origin style baseline fitting and peak area integration, and same batch testing environment. The variable parameters are: sample composition: Example 1 is a flexible polyol system composed of CO2-based polycarbonate diol / soybean oil polyol and constructed with a double-ended functionalized polysiloxane surface layer, and Comparative Example 11 is without double-ended functionalized polysiloxane. Example 1 and Comparative Example 11 exhibited Tg values ​​of approximately -22 °C and -18 °C, respectively, both falling within the target range of -25 to -15 °C. Example 1 showed a melting peak Tm of approximately 44.5 °C, ΔHm of approximately 8.9 J / g, and crystallinity of approximately 8.9%, while Comparative Example 11 showed a Tm of approximately 42.5 °C, ΔHm of approximately 6.3 J / g, and crystallinity of approximately 6.3%, both within the target range of 5–12%. The superimposed curves show that Example 1 exhibits a slightly gentler Cp step in the glass transition region and a larger melting peak area, demonstrating that the flexible polyol compound combined with a silicon-oxygen network surface layer helps to reduce Tg and increase a moderate degree of semi-crystallization, thereby achieving a better balance between hardness and toughness.

[0085] Figure 7 For the comparison of the FTIR (transmission) spectra of Example 1 and Comparative Example 12, the parameters were fixed as follows: test mode transmission and wavenumber range of 4000 to 400 cm⁻¹. -1 2 cm step -1 The display uses a smooth window with 5 points; the peak integral employs endpoint linear baseline subtraction and the trapezoidal method; the key peak windows are set to 3350±80, 1730±20, 1100±30, and 1050±20 cm. -1The varying parameters are the differences in sample formulation and the content of silicon / carbonate functional groups. Example 1 was performed at 1100 cm⁻¹. -1 The antisymmetric stretching absorption of Si–O–Si is significantly enhanced at 1730 cm⁻¹. -1 The C=O stretching strength is basically close to that of the comparative example, 1050 cm. -1 The C–O–C absorption is moderate and 3350 cm⁻¹ -1 The N–H absorption did not show abnormal deepening, and the overall transmission baseline consistency between the two was good and comparable to the noise level; Comparative Example 12 showed good N–H absorption at 1100 cm⁻¹. -1 Both the peak intensity and the integral area were significantly lower than in Example 1, while 1730 and 1050 cm² were significantly lower. -1 The difference is small, 3350 cm -1 No significant scale-up was observed. The conclusion is that Example 1 exhibits higher Si–O–Si characteristic intensity and area, indicating more complete silicon-oxygen bridging and network construction without sacrificing the balance of carbonate and ether bonds, demonstrating that the structural design achieves targeted enhancement and corroborates baseline stability.

[0086] As can be seen from the performance of the examples and comparative examples in Table 1, the four examples are significantly superior to most of the comparative examples in terms of comprehensive performance, including dry friction coefficient, wear resistance, hydrophobicity and oleophobicity, and low VOC. Comparative Example 1 suffered from insufficient latex particle stability due to an excessively low amount of hydrophilic chain extender, resulting in decreased hydrophilicity of the coating surface, a water contact angle of only 98°, and a dry friction coefficient as low as 0.48, failing to meet anti-slip requirements. Comparative Example 2, although it increased the amount of hydrophilic chain extender, exceeded the optimal range, leading to increased water absorption and a higher surface free energy. Comparative Example 3 suffered from a loose network structure due to an excessively low gel fraction, resulting in a significant decrease in wear resistance to 0.042 g / 500 rpm and a dry friction coefficient of only 0.44. Comparative Examples 4 and 6 suffered from insufficient amounts of bifunctionalized polysiloxane or insufficient silicon content, limiting their surface hydrophobic and oleophobic properties, with water contact angles of 102° and 104°, respectively, and hexadecane contact angles as low as 48° and 50°. Comparative Example 11 completely lacked the bifunctionalized polysiloxane, resulting in a surface free energy as high as 26.8 mN / m, severely insufficient hydrophobic and oleophobic properties, and a dry friction coefficient reduced to 0.46. Comparative Example 12 did not construct a silicon-oxygen network surface layer; although it maintained a relatively good friction coefficient of 0.60, the water contact angle plummeted to 88°, the surface free energy reached as high as 32.5 mN / m, and it lost its anti-fouling function. Comparative Example 13, with excessive crosslinking monomers, caused over-crosslinking of the network, increased the brittleness of the coating film, reduced the dry friction coefficient to 0.42, and increased the wear loss to 0.045 g. In contrast, the embodiments, through precise control of the synergistic configuration of 1.6-2.3 wt% hydrophilic chain extender, 2.5-4.8 wt% bifunctionalized polysiloxane, 86-93 wt% gel fraction, and 20-80 nm silicon-oxygen network surface layer, achieved excellent comprehensive performance with a high coefficient of friction of 0.55-0.68, low wear loss of 0.014-0.025 g, high hydrophobic and oleophobic water contact angle of 108-117°, hexadecane contact angle of 53-64°, low surface free energy of 16.8-20.2 mN / m, and low VOC content of 28-46 g / L, thus verifying the scientific nature and superiority of the technical solution of the present invention.

[0087] Table 1 summarizes the topcoat performance of the examples and comparative examples: Sample number Dry friction coefficient Wear mass loss (g / 500 rpm) Water contact angle (°) Contact angle of n-hexadecane (°) Surface free energy (mN / m) VOC content (g / L) gel fraction (wt%) Example 1 0.62±0.03 0.018±0.002 112±3 58±2 18.5±0.8 35±2 90±1.5 Example 2 0.58±0.02 0.022±0.003 108±2 53±3 19.8±0.9 28±2 87±1.8 Example 3 0.68±0.03 0.014±0.002 117±3 64±2 16.8±0.7 42±3 93±1.2 Example 4 0.55±0.02 0.025±0.003 110±2 56±2 20.2±1.0 46±3 86±2.0 Comparative Example 1 0.48±0.03 0.035±0.004 98±3 45±3 24.5±1.2 32±2 89±1.6 Comparative Example 2 0.52±0.02 0.028±0.003 105±3 52±2 21.3±0.9 38±2 91±1.4 Comparative Example 3 0.44±0.03 0.042±0.005 108±2 55±3 20.8±1.1 36±2 78±2.5 Comparative Example 4 0.51±0.02 0.032±0.003 102±3 48±2 23.2±1.0 34±2 88±1.7 Comparative Example 5 0.56±0.03 0.026±0.003 114±3 60±3 17.8±0.8 40±3 90±1.5 Comparative Example 6 0.53±0.02 0.030±0.003 104±2 50±2 22.5±0.9 35±2 89±1.6 Comparative Example 7 0.58±0.03 0.024±0.003 115±3 62±3 17.2±0.8 42±3 90±1.4 Comparative Example 8 0.54±0.02 0.029±0.003 106±2 52±2 21.8±1.0 36±2 89±1.7 Comparative Example 9 0.56±0.03 0.027±0.003 108±3 54±2 20.5±0.9 37±2 89±1.5 Comparative Example 10 0.50±0.02 0.033±0.004 118±3 66±3 16.2±0.7 48±3 90±1.6 Comparative Example 11 0.46±0.03 0.038±0.004 95±3 42±3 26.8±1.3 33±2 88±1.8 Comparative Example 12 0.60±0.03 0.020±0.002 88±3 35±3 32.5±1.5 34±2 90±1.5 Comparative Example 13 0.42±0.03 0.045±0.005 110±2 56±2 19.5±0.9 38±2 95±1.2

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that any equivalent structural transformations made under the concept of the present invention and using the contents of the specification and drawings of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. An aliphatic polyurethane high build topcoat characterized in that, Comprise: A) polyurethane phase formed by reaction of polyol component with aliphatic diisocyanate, containing 1.5wt%-2.5wt% hydrophilic chain extender units based on resin solids; B) polyacrylate network formed by polymerization of acrylate monomers, forming a semi-interpenetrating network structure with the polyurethane phase, with gel fraction ≥ 85wt%; C) 2.0wt%-5.0wt% of both end functionalized polysiloxane based on resin solids, containing hydrolysable condensable silane groups SiOR3, R being methyl or ethyl, and containing cyclic carbonate groups, with a number average functionality of 2.0±0.2, a silicon element mass fraction of 1.2wt%-2.5wt%, and a carbonate group content of 0.20-0.60mmol / g; D) a siloxane network surface layer formed by hydrolytic condensation of surface layer building silanes after coating and curing, with a thickness of 20-80nm; Wherein, the topcoat after film formation has a dry state friction coefficient ≥ 0.50, an abrasion mass loss ≤ 0.030g under 750g load / 500 revolutions, a water contact angle ≥ 105°, a n-hexadecane contact angle ≥ 50°, a surface free energy ≤ 22mN / m, and a volatile organic compound content ≤ 50g / L.

2. The finish of claim 1, wherein, The polyol component is composed of carbon dioxide based polycarbonate diol with a hydroxyl value of 56-120mgKOH / g and soybean oil polyol with a hydroxyl value of 120-220mgKOH / g; The aliphatic diisocyanate is selected from isophorone diisocyanate, hexamethylene diisocyanate or dicyclohexylmethane diisocyanate; The hydrophilic chain extender units are derived from dimethylolpropionic acid or dimethylolbutyric acid.

3. The topcoat of claim 1, wherein, The acrylate monomers are selected from one or more of butyl acrylate, methyl methacrylate, diethylhexyl acrylate, dihydroxyethyl methacrylate and dihydroxyethyl acrylate; 0-0.8wt% of crosslinking monomers based on the total amount of acrylate monomers can be optionally added; The crosslinking monomers are selected from ethylene glycol dimethacrylate, diethylene glycol diacrylate or methacryloyloxypropyl triethoxysilane.

4. The finish of claim 1 wherein, The silicon element atomic fraction of the siloxane network surface layer after coating and curing is 15at%-30at%, and there is a gradient distribution from 20% to 5% from the surface to a depth of 50nm.

5. A process for the preparation of the aliphatic polyurethane high-scrub- resistant topcoat according to any one of claims 1 to 4, characterized in that, Comprise the following steps: S1 reacting the polyol component with the aliphatic diisocyanate at an NCO / OH molar ratio of 1.6-1.9, adding a hydrophilic chain extender, and reacting at 70-85℃ until the NCO content is 2.0wt%-3.0wt%; S2 is subjected to phase inversion emulsification after adjusting the pH to 7.5-8.2 with a neutralizing agent, and the latex particle size D is controlled to be 80-180 nm 50 80-180 nm S3 completing chain extension by dropwise addition of 1.5wt%-2.5wt% chain extender aqueous solution; S4 initiating semi-continuous emulsion polymerization of the acrylate monomers at 65-75℃ with an initiator until the gel fraction is ≥ 85wt% and the residual monomer is < 200mg / kg; S5 adjusting the pH of the system to 6.8-7.2, adding both end functionalized polysiloxane and surface layer building silanes, and after coating and curing the surface layer thickness is 20-80nm; S6 when the solids content is 40 wt% to 50 wt% and the particle size D 50 of 80 to 180 nm.

6. The method of claim 5, wherein, The polyol component in step S1 is mixed in a ratio of 55-75 parts by mass of carbon dioxide-based polycarbonate diol and 25-45 parts by mass of soybean oil polyol, the hydrophilic chain extender is dimethylol propionic acid or dimethylol butyric acid, and the amount used is 1.5wt%-2.5wt% based on the resin solid, and the reaction is carried out under a nitrogen or argon protective atmosphere; the neutralizing agent in step S2 is triethylamine, and the water phase is added in stages for phase inversion emulsification, and the coefficient of variation is ≤0.25; the chain lengthening agent in step S3 is ethylenediamine or isophorone diamine, the dropwise addition time is 30-45 minutes, and the amount added is calculated according to the NCO / NH equivalent ratio of 0.95-1.05, and the dropwise addition is followed by incubation until the NCO residual amount is <0.10wt%.

7. The method of claim 5, wherein, The initiator in step S4 is ammonium persulfate, the acrylate monomer is selected from one or more of butyl acrylate, methyl methacrylate, diethylhexyl acrylate, dihydroxyethyl methacrylate and dihydroxyethyl acrylate, a crosslinking monomer can be optionally added in an amount of 0-0.8wt% based on the total amount of acrylate monomers, the crosslinking monomer is selected from ethylene glycol dimethacrylate, diethylene glycol diacrylate or methacryloyloxypropyl triethoxysilane, the conversion rate is ≥98wt%, and a redox system is used for post-treatment if necessary.

8. The method of claim 5, wherein, The amount of the double-end functionalized polysiloxane used in step S5 is 2.0wt%-5.0wt% based on the resin solid, the end groups thereof contain SiOR3 and can be hydrolyzed and condensed, R is methyl or ethyl, and the double-end functionalized polysiloxane contains a cyclic carbonate group, the number average functionality is 2.0±0.2, the mass fraction of silicon element is 1.2wt%-2.5wt%, and the content of carbonate groups is 0.20-0.60mmol / g; The total amount of the silane used for surface layer construction is 0.3wt%-1.0wt% based on the resin solid; after coating, curing and post-curing are carried out at 25-60℃ for 24 hours, and the atomic fraction of silicon element in the surface layer of the coating film is 15at%-30at%, and a gradient distribution of 20% to 5% is formed from the surface to a depth of 50nm.

9. The method of claim 5, wherein, The double-end functionalized polysiloxane is prepared according to the following steps: A1 raw material preparation: 100 parts by mass of hydroxyl-terminated polydimethylsiloxane, 15-25 parts by mass of 3-isocyanatopropyl triethoxysilane, 10-20 parts by mass of 3-glycidyloxypropyl trimethoxysilane, continuous supply of carbon dioxide under a pressure of 1.0-2.5MPa, 5-15 parts by mass of dimethyl carbonate or glycerol carbonate, and 0.1wt%-1.0wt% of tetrabutylammonium bromide or zinc acetate catalyst based on the total formulation; A2 carbonate end group introduction: conversion of 3-glycidyloxypropyl trimethoxysilane to a silane intermediate containing a cyclic carbonate end group under the action of carbon dioxide at 1.0-2.5MPa and at a temperature of 80-120℃, or under the action of dimethyl carbonate or glycerol carbonate as a carbonic acid source in the presence of tetrabutylammonium bromide or zinc acetate as a catalyst, and reaction for 6-12 hours; A3 urethanization and end group construction, reacting 3-isocyanatopropyl triethoxysilane with hydroxyl terminated polydimethylsiloxane at 60-90℃ for 1.5-4.0 hours, controlling isocyanate residual amount ≤0.20wt%, then hydrolytic condensation of the product with the intermediate described in step A2 in the presence of trace amount of water or alcohol, acid catalysis with pH controlled at 4.5-5.5 or base catalysis with pH controlled at 9.0-10.0, or keeping water-free condition if using a blending route, to obtain a double-end functionalized polysiloxane product; A4 termination and post-treatment, terminating when the silicon element mass fraction is 1.2wt%-2.5wt%, the carbonate group content is 0.20-0.60mmol / g, and the free monomer is ≤200mg / kg, removing alcohol under reduced pressure, filtering, and storing in a sealed water-free environment.

10. Use of the topcoat according to claims 1 to 4 or the topcoat obtained by the method according to claims 5 to 9 in an anti-fouling, anti-skid, wear-resistant coating for industrial floors and metal substrates, characterized in that, Suitable for dry workshop, parking lot and light chemical industry scene, the dry film friction coefficient ≥0.50 and the wear mass loss ≤0.030g / 500 turns.

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