A polycarbonate polyol water repellent coating

Abstract

The application discloses a polycarbonate polyol waterproof coating and belongs to the technical field of high polymer coating. The polycarbonate polyol waterproof coating comprises an A component and a B component, the A component comprises polycarbonate polyol which is prepared by copolymerization of carbon dioxide and an epoxide compound under the action of a catalyst and with a core polyol as a chain transfer agent. The A component can further comprise polyether polyol; the polycarbonate polyol can be of an ultrabranched structure and has a hydroxyl functionality of no less than 3. The B component is an isocyanate curing agent selected from HDI, MDI, TDI or IPDI. The A component and the B component are mixed at an NCO / OH equivalent ratio of 1 to 1.10:1. By introducing rigid epoxy cyclohexane segments and an ultrabranched structure, the hardness, wear resistance and barrier property of the coating are significantly improved, while good flexibility and workability are maintained, and the polycarbonate polyol waterproof coating can be used in the field of high-performance floor coating.

Description

Technical Field

[0001] This invention relates to the field of polymer coating technology, specifically to a polycarbonate polyol waterproof coating. Background Technology

[0002] Epoxy floor coatings are widely used in industrial and commercial flooring due to their excellent adhesion, hardness, and chemical resistance. However, traditional epoxy resin flooring systems have some inherent limitations: First, their raw materials are highly dependent on non-renewable petroleum resources; second, the amine curing agents used have a certain degree of toxicity and irritation; third, the cured coating is relatively brittle and prone to cracking under temperature changes or impact loads; in addition, its degradation properties are poor, which does not meet increasingly stringent environmental protection and sustainable development requirements.

[0003] To overcome the aforementioned problems, researchers have begun exploring environmentally friendly polymers using carbon dioxide as a raw material. Among them, polypropylene carbonate (PPC) polyols, obtained by copolymerizing CO2 and propylene oxide (PO), have attracted considerable attention, offering a feasible pathway for utilizing greenhouse gases and developing bio-based materials. Polyurethane materials prepared using such polyols as a matrix have exhibited certain flexibility and degradability. However, pure PPC-based polyurethanes suffer from insufficient mechanical strength, poor heat resistance, low hardness, and susceptibility to creep. Their rigidity, abrasion resistance, and barrier properties are far from meeting the requirements of high-performance floor coatings, especially for industrial floors that need to withstand heavy loads and high abrasion. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a polycarbonate polyol waterproof coating that has excellent rigidity, wear resistance and barrier properties.

[0005] The technical solution adopted by the present invention to solve its technical problem is: a polycarbonate polyol waterproof coating, comprising component A and component B, wherein component A contains polycarbonate polyol, wherein the polycarbonate polyol is copolymerized by carbon dioxide and epoxy compound under the action of a catalyst, with the core polyol as a chain transfer agent; wherein the epoxy compound is selected from one or more combinations of propylene oxide, ethylene oxide, and cyclohexane oxide.

[0006] This invention uses carbon dioxide and epoxy compounds such as propylene oxide (PO), ethylene oxide (EO), and cyclohexane oxide (CHO) as comonomers. Using carbon dioxide as a raw material embodies the concepts of green environmental protection and resource reuse, reducing dependence on petroleum resources. PO provides flexible chain segments, ensuring the coating's toughness and workability; EO can further adjust flexibility and compatibility; while the rigid cyclic structure of CHO can significantly improve the rigidity of the polymer chain and its glass transition temperature. The polycarbonate polyol formed by the copolymerization of these three compounds simultaneously introduces flexible and rigid units into its molecular chain, laying the foundation for the coating's excellent toughness and high hardness from a molecular structure perspective. Furthermore, this polyol contains a large number of reactive hydroxyl groups, which can crosslink and cure with the isocyanate groups of component B, forming a dense polyurethane network, ensuring the coating possesses excellent comprehensive performance.

[0007] In some embodiments of the present invention, the polycarbonate polyol may employ a hyperbranched structure. Compared to traditional linear or simple star-shaped structures, hyperbranched molecules possess a three-dimensional spherical topology, a large number of terminal functional groups, and low melt viscosity. In coating applications, high functionality means that a three-dimensional network with a higher crosslinking density can be formed during curing, thereby greatly improving the coating's hardness, abrasion resistance, chemical resistance, and dimensional stability. Moreover, the low viscosity characteristic allows for good application leveling without the need for excessive solvent addition, which is beneficial for formulating environmentally friendly coatings with high solids content and low VOCs. It should be noted that the present invention does not limit the polycarbonate polyol to a hyperbranched structure; linear polycarbonate polyols or mixed polyols with functionality 2 and functionality 3 can also implement the present invention.

[0008] Preferably, when using hyperbranched polycarbonate polyols, the hydroxyl functionality is greater than or equal to 3, and the number-average molecular weight is 1000-3000. A functionality of ≥3 ensures that the molecule has sufficient reaction sites to form a highly cross-linked network; preferably, a functionality greater than 6 can further multiply the cross-linking points, making the coating network denser. Controlling the number-average molecular weight (Mn) within the lower range of 1000-3000 avoids that excessively high molecular weight will cause a sharp increase in resin viscosity, affecting the workability and filler wettability of the coating; while excessively low molecular weight will make the cured coating brittle. This molecular weight range can ensure that the resin has low viscosity and is easy to handle, while giving the cured coating an optimal balance of mechanical strength and toughness.

[0009] Preferably, component A is a mixture of polycarbonate polyol and polyether polyol in a mass ratio of 100:0~80. The introduction of polyether polyol can further adjust the flexibility of the coating, reduce raw material costs, and improve the wetting and penetration of the coating onto the substrate. The amount of polyether polyol can be adjusted according to the required performance; when no addition is required, it constitutes a pure polycarbonate polyol system.

[0010] Preferably, the method for synthesizing the hyperbranched polycarbonate polyol includes the following steps:

[0011] (1) The core polyol and catalyst are placed in the reaction apparatus for dehydration treatment;

[0012] (2) Add 60% to 70% of the total amount of propylene oxide as the first part of the propylene oxide feed, and carry out the copolymerization reaction for 2 to 3 hours by introducing carbon dioxide into the system at 60°C to 85°C to a pressure of 1.1 MPa to 3.5 MPa.

[0013] (3) Using a pulse feeding method, a batch of mixed monomers containing cyclohexane oxide and the remaining second part of propylene oxide is added every 15 min to 20 min, and the copolymerization reaction continues for 3 h to 4 h under the condition of maintaining carbon dioxide pressure;

[0014] (4) After the reaction is completed, the hyperbranched polycarbonate polyol is obtained by termination, devolatilization and granulation.

[0015] The process begins by adding most of the PO (polypropylene oxide) to react with CO2, aiming to preferentially form flexible polypropylene carbonate (PPC) segments as the molecular backbone, ensuring the product's flexibility. The pulse feeding process mixes CHO (carbon oxynitrate) with the remaining PO and adds it in batches, effectively controlling the distribution of rigid CHO segments within the molecular chain. These segments tend to accumulate at the outer ends of branches, maximizing their rigidity-enhancing effect. Simultaneously, this feeding method, combined with catalytic properties, promotes chain transfer reactions, favoring the formation of well-defined hyperbranched structures rather than simple linear block copolymers. The entire process, through the coordinated control of temperature, pressure, and feeding procedures, achieves precise regulation of the polymer topology and segment sequence.

[0016] Preferably, the catalyst is a combination of trialkylboron and onium salt. This composite catalyst exhibits high activity and selectivity for the copolymerization reaction of CO2, PO, and CHO, effectively promoting a reduction in the content of cyclic carbonate byproducts, with the main product being predominantly polycarbonate. Trialkylboron acts as an activator of the epoxy monomers, while the onium salt, as a nucleophile or co-catalyst, assists in ring-opening and CO2 insertion. This catalytic system enables the controlled copolymerization of ternary monomers under relatively mild conditions.

[0017] Preferably, the core polyol in step (1) is trimethylolpropane (TMP) or pentaerythritol. TMP and pentaerythritol are ideal cores for synthesizing hyperbranched or star polymers. Polymerization using them as initiators can directly obtain polymer cores with functionalities of 3 or 4, providing a clear topological starting point for constructing multi-arm or even hyperbranched structures. Compared to using diols such as ethylene glycol, using TMP or pentaerythritol can more directly and efficiently prepare high-functionality polyols, thereby achieving higher crosslinking density and superior coating hardness, solvent resistance, and other properties during subsequent coating curing.

[0018] Preferably, the dehydration treatment in step (1) is specifically a dehydration treatment at 120°C and a vacuum of -0.095 MPa for 2 hours under an inert atmosphere.

[0019] Preferably, the devolatilization treatment in step (4) is carried out under vacuum conditions of 120℃~140℃ and -0.099MPa. Under these conditions, unreacted monomers, oligomers and other small molecule volatiles remaining in the polymer melt can be efficiently and completely removed, improving the purity of the product and preventing small molecule substances from migrating and volatilizing during the storage or curing of the coating, thus affecting the appearance and performance of the coating.

[0020] Preferably, component A further includes a filler, which is nano-silica treated with a silane coupling agent. After the surface hydroxyl groups of the silane-coupling agent-treated nano-silica react with the coupling agent, the remaining organic functional groups can form chemical bonds or strong interactions with the hydroxyl groups of the polycarbonate polyol or the cured polyurethane network, greatly improving the interfacial compatibility between the nanoparticles and the resin matrix and preventing their aggregation. Uniformly dispersed nano-silica can produce significant reinforcing and toughening effects, and greatly improve the hardness, wear resistance, and scratch resistance of the coating.

[0021] Preferably, component B is an isocyanate, selected from one or more combinations of HDI, MDI, TDI, or IPDI. Using aromatic isocyanates can reduce costs and improve reactivity; using aliphatic isocyanates can balance yellowing resistance and weather resistance, allowing users to choose flexibly according to their application scenarios. In a preferred embodiment of the invention, HDI trimer or HDI biuret is used as a curing agent. HDI trimer has high functionality and a rigid structure, resulting in a high-hardness coating with good chemical resistance after curing; HDI biuret contains a urea-formate structure, giving the coating good flexibility and adhesion. Both can react with the hydroxyl groups of component A to form a polyurethane / polyurea network.

[0022] Preferably, when component A and component B are mixed, the equivalent ratio of NCO to OH is 1 to 1.10:1. Strictly controlling the R value within the range of 1 to 1.10 ensures that the isocyanate reacts fully to form a complete and balanced cross-linked network, thereby achieving the optimal balance of mechanical properties, chemical resistance, and durability.

[0023] More preferably, when the coating is used as a primer, the equivalent ratio of NCO to OH is 0.9:1; when used as an intermediate coat, the equivalent ratio is 1.0:1; and when used as a topcoat, the equivalent ratio is 1.05:1 to 1.10:1. The primer has a slightly lower R-value, resulting in a small amount of residual hydroxyl groups after curing. These polar hydroxyl groups can better form hydrogen bonds with the hydroxyl groups on the concrete substrate surface, enhancing adhesion. Simultaneously, the coating exhibits slightly better flexibility, facilitating penetration and stress buffering. The intermediate coat has an R-value of 1.0:1, aiming for complete reaction and balanced performance. As a transitional layer, it provides the main thickness and mechanical strength. The topcoat has a slightly higher R-value; a small excess of NCO can react with ambient moisture to form polyurea, further improving the crosslinking density, hardness, abrasion resistance, and chemical resistance of the coating surface, meeting the performance requirements of the topcoat. It should be noted that the primer R value of 0.9:1 is a more preferred further limitation. Cases that fall outside the range of 1 to 1.10:1 are only adaptive adjustments under special construction conditions and are not general limitations of the present invention.

[0024] This coating is used to form a multi-layer coating system, including a primer layer, an intermediate layer and a topcoat layer arranged sequentially from bottom to top; wherein, the dry film thickness of the topcoat layer is 80μm~120μm, and it is cured for more than 7 days in an environment with a temperature of 25℃ and a humidity of less than 75% after application.

[0025] The primer layer focuses on penetration and adhesion, the intermediate layer provides thickness, strength, and impact resistance, and the topcoat layer undertakes the highest requirements for abrasion resistance, stain resistance, and aesthetics. This layered design achieves an optimized balance between performance and cost. Limiting the topcoat dry film thickness to 80-120 μm ensures sufficient abrasion-resistant layer thickness; too thin and it becomes ineffective, too thick and it may increase internal stress leading to cracking. Curing at 25°C and <75% humidity for at least 7 days ensures a near-complete curing reaction, allowing the coating's physical, mechanical, and chemical properties to reach stability and optimal levels, guaranteeing a long service life for the flooring.

[0026] Compared with existing technologies, this invention has the following beneficial effects: This invention copolymerizes carbon dioxide with epoxy compounds such as propylene oxide, ethylene oxide, and cyclohexane oxide, combined with a hyperbranched or linear / branched mixed polycarbonate polyol structure, achieving synergy between rigid ring segments and flexible chain segments at the molecular level. This significantly improves the hardness, wear resistance, and barrier properties of the coating, effectively solving the problem of insufficient mechanical strength in traditional CO2-based coatings. The hyperbranched topology brings high functionality and low viscosity, resulting in higher crosslinking density and excellent workability. Simultaneously, the layered design and multi-layer system construction using curing agent equivalence ratios balance adhesion, impact resistance, and surface weather resistance. The introduction of polyether polyols (mass ratio 100:0~80) further adjusts the coating's flexibility, reduces costs, and improves wetting and penetration into the substrate. Furthermore, the use of various isocyanates such as HDI, MDI, TDI, and IPDI, along with nanofillers treated with coupling agents, ensures environmentally friendly carbon fixation and low VOCs while achieving a comprehensive performance breakthrough that makes it durable and a viable alternative to traditional epoxy floor paints. Detailed Implementation

[0027] The present invention will be specifically described below through examples. Unless otherwise stated, all raw materials used are commercially available. It should be noted that the polycarbonate polyols in the following examples are all illustrated using hyperbranched structures, but the present invention is not limited thereto. Linear / branched mixed polycarbonate polyols and mixed systems of polycarbonate polyols and polyether polyols are also within the scope of protection of the present invention, and those skilled in the art can select and adjust them according to actual needs.

[0028] Example 1

[0029] The synthesis of hyperbranched polycarbonate polyols uses 134 g of trimethylolpropane (1.0 mol) as the core, combined with a catalyst consisting of triethylboron and tetrabutylammonium bromide in a 1:1 molar ratio (mass fraction of 0.03% of the total monomer mass). After dehydration, 930 g of propylene oxide (16.0 mol) was added first at 65 °C and a CO2 pressure of 1.5 MPa to construct a flexible framework. Subsequently, the temperature was raised to 95 °C, and a mixed monomer containing cyclohexane oxide (70 g / batch) and the remaining propylene oxide (125 g / batch) was added in four batches at 18-minute intervals, while maintaining a CO2 pressure of 3.0 MPa for another 3.5 h. After the reaction was completed, a 1 wt% phosphoric acid methanol solution with a mass fraction of 1% of the total mass of the reaction product was added to terminate the reaction. The product was then treated in a twin-screw devolatilizer at 130℃ and -0.099MPa vacuum at 250rpm for 40min to finally obtain HB-PCP resin with a number average molecular weight of about 2800 and a functionality of about 9.2.

[0030] Preparation of floor coating: Primer component A consists of 100 parts by weight of HB-PCP, 5 parts by weight of silane coupling agent KH-550, 30 parts by weight of quartz powder and 4 parts by weight of xylene, and is mixed with component B HDI biuret at NCO / OH = 0.9:1 (mass ratio of about 100:66).

[0031] The intermediate coating component A consists of 100 parts by weight of HB-PCP, 15 parts by weight of methyl methacrylate-butadiene-styrene, 80 parts by weight of heavy calcium carbonate and 0.5 parts of leveling agent, which are mixed with HDI trimer at NCO / OH = 1.0:1 (mass ratio approximately 100:69).

[0032] The topcoat component A consists of 100 parts by weight of HB-PCP, 12 parts by weight of KH-560-treated nano-silica, 8 parts by weight of polyurea-formaldehyde microcapsules, 0.3 parts by weight of BYK-088 defoamer, and 0.5 parts by weight of BYK-333 leveling agent, mixed with HDI trimer at an NCO / OH ratio of 1.08:1 (approximately 100:73.8 by mass). All components are dispersed at high speed, ground to a fineness ≤30μm, and defoamed before use.

[0033] During construction, after the concrete substrate is treated, a 60μm primer (dry film), a 150μm intermediate coat (dry film), and a 100μm topcoat (dry film) are applied sequentially. The topcoat is applied using high-pressure airless spraying, with the pressure controlled at 18MPa. After curing the coating for 7 days at 25℃ and humidity <75%, tests show that its pencil hardness reaches 3H, its abrasion resistance is excellent, its adhesion is grade 0, and its overall performance meets the requirements of high-standard flooring.

[0034] Example 2

[0035] The synthesis of hyperbranched polycarbonate polyols used 136 g pentaerythritol (1.0 mol) as the core initiator, employing the same triethylboron / tetrabutylammonium bromide catalyst system as in Example 1, at a concentration of 0.03% of the total monomer mass. After dehydration, 860 g of propylene oxide (14.8 mol), representing 60% of the total feed, was added at 60 °C and a CO2 pressure of 1.1 MPa. The reaction was carried out at 60 °C for 3 h to construct the initial flexible framework. Subsequently, the reaction temperature was raised to 85 °C, and a mixed monomer consisting of 308 g of cyclohexane oxide (3.1 mol) and the remaining 575 g of propylene oxide (9.9 mol) was added in five batches every 20 min using a pulse feeding method. The reaction was continued for 4 h while maintaining a CO2 pressure of 2.5 MPa. After the reaction was completed, a phosphoric acid methanol solution in the same proportion as in Example 1 was added to terminate the reaction. The product was treated in a twin-screw devourer at 120°C and -0.099 MPa vacuum for 50 min to finally obtain an HB-PCP resin with a number-average molecular weight of approximately 1000 and a hydroxyl functionality of approximately 4. The molecular weight of this resin is at the lower limit of the range described in the claims, and the functionality is determined by the four hydroxyl groups of pentaerythritol, providing a basis for constructing different topologies. Based on this resin, the intermediate coating component A was prepared, consisting of 100 parts by weight of this HB-PCP, 20 parts by weight of a core-shell type acrylate impact-resistant agent, 100 parts by weight of 800-mesh heavy calcium carbonate, and 0.8 parts by weight of a leveling agent, which were mixed with HDI trimer at an equivalent ratio of NCO / OH = 1.0:1. The dry film thickness of the intermediate coating formed by the application was 200 μm, and the test showed excellent impact resistance and flexibility, verifying the application potential of low molecular weight, moderately functionalized resin in thickening coatings.

[0036] Example 3

[0037] A catalyst composed of tri-n-butylboron and tetraphenylphosphonium bromide in a 1:1 molar ratio was used. The synthesis employed 134 g of trimethylolpropane (1.0 mol) as the core, which, after dehydration, was followed by the addition of 1000 g of propylene oxide (17.2 mol), representing 70% of the total propylene oxide feed, under high pressure conditions of 3.5 MPa and 85 °C. The reaction proceeded for 2 hours to form flexible segments. Subsequently, while maintaining the temperature at 85 °C, a mixed monomer consisting of 196 g of cyclohexane oxide (2.0 mol) and the remaining 430 g of PO (7.4 mol) was rapidly added in three batches every 15 minutes using a pulse feeding method. Throughout the feeding process and the subsequent 3 hours of reaction, the CO2 pressure was maintained at the upper limit of 3.5 MPa. This high-pressure condition was designed to investigate its effect on the reaction rate and molecular weight increase. The reaction termination and post-treatment conditions were the same as in Example 1, ultimately yielding an HB-PCP resin with a number-average molecular weight of approximately 3000 and a functionality of approximately 8.5. The topcoat component A, formulated using this resin, consists of 100 parts by weight of HB-PCP, 15 parts by weight of nano-silica treated with γ-(methacryloyloxy)propyltrimethoxysilane (KH-570), 5 parts by weight of polyurea-formaldehyde resin-coated lubricant microcapsules, 0.2 parts by weight of defoamer, and 0.6 parts by weight of leveling agent. Component B is HDI biuret, mixed at the upper limit of the NCO / OH equivalent ratio of 1.10:1 to achieve the highest surface crosslinking density. After application, a topcoat layer with a dry film thickness of 80 μm is formed. Tests show that it has extremely high surface hardness and excellent chemical solvent resistance, demonstrating the effect of high-pressure synthesis combined with a high NCO / OH ratio on improving the top performance of the coating.

[0038] Example 4

[0039] The HB-PCP resin synthesized in Example 1 was used directly. Primer component A was prepared, consisting of 100 parts by weight of HB-PCP, 3 parts by weight of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH-792), 40 parts by weight of 400-mesh quartz powder, and 5 parts by weight of xylene diluent. Component B was an HDI trimer, but the equivalent ratio of NCO to OH was intentionally set to 0.9:1. This low ratio design aims to retain more hydroxyl groups in the cured coating to optimize adhesion and penetration to damp concrete substrates. During application, the mixed primer was roller-coated onto the treated substrate to form a coating with a dry film thickness of approximately 50 μm. Curing was carried out under conditions of low ambient temperature (15℃) and high relative humidity (approximately 80%). After 7 days, the adhesion between the coating and the concrete substrate still reached level 1, and the coating film was flexible and crack-free. This verifies that even under non-ideal construction conditions, the basic performance of the coating can still be guaranteed by using a lower NCO / OH ratio formulation, demonstrating the construction tolerance and adaptability of the formulation of this invention within a certain range.

[0040] Example 5

[0041] The synthesis used 134 g of trimethylolpropane (1.0 mol) as the core monomer and triethylboron and tetrabutylammonium bromide (molar ratio 1:1) as the catalyst. First, the core polyol and catalyst underwent a rigorous 2-hour dehydration treatment at 120 °C and -0.095 MPa vacuum under an inert atmosphere to completely remove trace amounts of water; this is a crucial pretreatment step for obtaining a highly active polymerization system. After dehydration, 1000 g of PO (17.2 mol), accounting for 65% of the total propylene oxide feed, was added at 80 °C and a CO2 pressure of 2.0 MPa, and the reaction was allowed to proceed for 2.5 hours. Subsequently, the temperature was raised to 100 °C, and a mixed monomer consisting of 392 g of cyclohexane oxide (4.0 mol) and the remaining 538 g of PO (9.3 mol) was added every 15 minutes using the preferred pulse feeding method described in the instructions, for a total of 5 batches. The CO2 pressure was maintained at 3.2 MPa throughout the feeding and subsequent reaction for 4 hours. After the reaction was terminated, the product was devolatilized at 140℃ and -0.099MPa high vacuum to obtain HB-PCP resin with a number average molecular weight of approximately 2500 and a hydroxyl functionality of approximately 9.5. Its high functionality directly stems from the trifunctional starting point of trimethylolpropane and the successful hyperbranching polymerization. Using this resin, the intermediate coating component A was mixed with HDI trimer at an NCO / OH ratio of 1.0:1. Component A consisted of 100 parts by weight of HB-PCP, 10 parts by weight of core-shell ACR impact modifier, and 60 parts by weight of sericite. The resulting coating exhibited extremely high crosslinking density and excellent compressive strength.

[0042] Example 6

[0043] The catalyst was composed of triisobutylboron and methyltrioctylammonium chloride in a molar ratio of 1:1. The synthesis used 136 g of pentaerythritol (1.0 mol) as the core, and the dehydration process was the same as in Example 5. Polymerization was initiated at 75 °C and a CO2 pressure of 2.5 MPa, with 70% of the first portion (1000 g PO, 17.2 mol) added and reacted for 2 h. Subsequently, a pulse feeding method was used, adding a mixture of 245 g CHO (2.5 mol) and the remaining 430 g PO (7.4 mol) in five batches every 20 min, maintaining the pressure at 3.0 MPa for 3.5 h. Post-reaction treatment was carried out at 135 °C and a vacuum of -0.099 MPa to obtain HB-PCP resin with a number average molecular weight of approximately 1800 and a functionality of approximately 4.8. The topcoat component A prepared with this resin contains 100 parts by weight of resin, 10 parts by weight of nano-alumina treated with KH-560, 5 parts by weight of polyurea-formaldehyde microcapsules and appropriate additives. When mixed with HDI biuret at NCO / OH = 1.06:1, the resulting topcoat exhibits a wear resistance (750g / 500r) with a weight loss of less than 15mg and outstanding weather resistance.

[0044] Example 7

[0045] Using trimethylolpropane as the core and the same catalyst as in Example 1, the first step of PO (65%) polymerization was carried out at 70°C and a CO2 pressure of 1.8 MPa after optimal dehydration. In the crucial second step, after heating to 90°C, a batch of mixed monomers (308 g CHO, 3.1 mol) of CHO and the remaining PO was pulsed every 18 minutes, for a total of 4 batches. The CO2 pressure was maintained at 2.8 MPa, and the total reaction time was 3.5 hours. This pulsed feeding process effectively promoted the enrichment of CHO units at the branch ends and facilitated chain transfer reactions, which is beneficial for forming a highly branched structure. After the reaction, the product was devolatilized in a thin-film evaporator for 40 minutes under the preferred conditions of 120°C and -0.099 MPa vacuum, efficiently removing residual monomers to obtain a light-colored, high-purity HB-PCP resin with a number-average molecular weight of approximately 2200 and a functionality of approximately 8.8. When this resin is used in a primer formulation (100 parts by weight of resin, 8 parts by weight of KH-550, 25 parts by weight of quartz powder, and 3 parts by weight of xylene), and mixed with HDI biuret at NCO / OH = 0.9:1, it exhibits excellent penetration and adhesion to concrete substrates.

[0046] Example 8

[0047] The HB-PCP resin synthesized in Example 1 was used. Component A of the topcoat was specifically designed as follows: 100 parts by weight of HB-PCP, 18 parts by weight of nano-silica treated with KH-560, 2 parts by weight of polytetrafluoroethylene wax powder as an auxiliary lubricant and wear-resistant agent, 0.4 parts by weight of defoamer, and 0.5 parts by weight of leveling agent. Component B was an HDI trimer, mixed at NCO / OH = 1.05:1. In application, a multi-layer system was constructed: first, a primer prepared according to Example 7 (dry film thickness 60 μm) was applied, then a flexible intermediate coat prepared according to Example 5 (dry film thickness 180 μm) was applied, and finally, the high-wear-resistant topcoat of this example was sprayed, with the topcoat dry film thickness precisely controlled at 80 μm. The entire system was cured for more than 7 days at 25°C and <70% humidity. Test results showed that the complete coating system exhibited excellent overall performance, with a surface pencil hardness of 4H, adhesion grade 0, excellent wear resistance, and strong interlayer bonding without interlayer delamination.

[0048] Example 9

[0049] A linear polycarbonate polyol copolymerized from CO2, PO, and CHO was synthesized. 62 g of ethylene glycol (1.0 mol) was used as a difunctional initiator, employing the same catalyst system. The polymerization process utilized a conventional one-time mixed monomer feeding method: all 1430 g of propylene oxide (24.6 mol) and 280 g of cyclohexane oxide (2.8 mol) were mixed and copolymerized with CO2 at 80 °C and 3.0 MPa for approximately 5 h. After the reaction, the linear copolymer polyol was obtained with a number-average molecular weight of approximately 3000, but a functionality of only 2. Using this linear polyol, a coating was prepared according to the formulation and application process of the topcoat in Example 1.

[0050] This embodiment demonstrates that even when using linear difunctional polycarbonate polyols (functionality 2), the coating of the present invention can still achieve a hardness of 2H and an adhesion rating of 1, meeting the requirements for general flooring applications, thus reflecting the wide applicability of the present invention.

[0051] Comparative Example 1

[0052] The synthesis process of Example 1 was followed, but only carbon dioxide and propylene oxide monomers were used for copolymerization. Specifically, the same mass of trimethylolpropane was used as the core, and the same ratio of triethylboron / tetrabutylammonium bromide catalyst was employed. After dehydration, 1430g of propylene oxide (24.6mol), the same total PO feed amount as in Example 1, was added at once under the same temperature and pressure conditions. The reaction was carried out at 70℃~75℃ for about 6 hours until the CO2 pressure no longer decreased significantly. The reaction termination and post-treatment conditions were the same as in Example 1. A flexible polypropylene carbonate (PPC) polyol was finally obtained, with a number-average molecular weight of approximately 3000, but its functionality was significantly lower than that of HB-PCP in Example 1. Using this PPC polyol, a coating was prepared and applied exactly according to the formulation and ratio of the topcoat in Example 1, forming a coating with the same dry film thickness, and cured under the same conditions for 7 days.

[0053] Performance tests showed that the coating had a pencil hardness of only H-2H, a wear resistance (750g / 500r) weight loss >50mg, and poor heat resistance, exhibiting significant softening and deformation at 60℃. Compared with the results of Example 1 (hardness 3H, wear resistance weight loss <20mg), this clearly demonstrates that the introduction of the CHO rigid monomer plays an indispensable and crucial role in significantly improving the coating's hardness, wear resistance, and heat resistance.

[0054] The specific performance test results of all embodiments and comparative examples are summarized in Table 1. Unless otherwise stated, the performance tests of the following embodiments and comparative examples were conducted in accordance with the following national standards: pencil hardness was determined according to GB / T6739-2022; abrasion resistance was determined according to GB / T1768-2006; adhesion was determined according to GB / T9286-2021.

[0055] Table 1 Performance Test Results

[0056] .

[0057] Table 1 shows the main performance test results of each embodiment and comparative example. Specifically, the pencil hardness of Examples 1-8 reached 2H-4H, the abrasion resistance (750g / 500r) weight loss was 9-37mg, and the adhesion was mostly grade 0; Example 9 used a linear polyol, resulting in slightly lower performance; Comparative Example 1, lacking the rigid cyclohexane oxide monomer, had a hardness of only H-2H, abrasion resistance weight loss of 53mg, and an adhesion grade of 2. The results indicate that this invention significantly improves the hardness, abrasion resistance, and adhesion of the coating by introducing rigid cyclohexane segments and a hyperbranched structure.

Claims

1. A polycarbonate polyol waterproof coating, characterized in that, It includes component A and component B. Component A contains polycarbonate polyol, which is copolymerized by copolymerizing carbon dioxide and epoxy compound under the action of a catalyst, with the core polyol as a chain transfer agent. The epoxy compound is selected from one or more of propylene oxide, ethylene oxide, and cyclohexane oxide.

2. The polycarbonate polyol waterproof coating according to claim 1, characterized in that, Component A is a mixture of polycarbonate polyol and polyether polyol in a mass ratio of 100:0~80.

3. The polycarbonate polyol waterproof coating according to claim 2, characterized in that, The polycarbonate polyol is a mixture of polycarbonate polyol with hydroxyl functionality 2 and polycarbonate polyol with hydroxyl functionality 3 in a mass ratio of 100:0~30; the number average molecular weight of the polycarbonate polyol is 1000~3000.

4. A polycarbonate polyol waterproof coating according to claim 2 or 3, characterized in that, The method for synthesizing the hyperbranched polycarbonate polyol includes the following steps: (1) The core polyol and catalyst are placed in the reaction apparatus for dehydration treatment; (2) Add 60% to 70% of the total amount of propylene oxide as the first part of the propylene oxide feed, and carry out the copolymerization reaction for 2 to 3 hours by introducing carbon dioxide into the system at 60°C to 85°C to a pressure of 1.1 MPa to 3.5 MPa. (3) Using a pulse feeding method, a batch of mixed monomers containing cyclohexane oxide and the remaining second part of propylene oxide is added every 15 min to 20 min, and the copolymerization reaction continues for 3 h to 4 h under the condition of maintaining carbon dioxide pressure; (4) After the reaction is completed, the hyperbranched polycarbonate polyol is obtained by termination, devolatilization and granulation.

5. A polycarbonate polyol waterproof coating according to claim 1 or 4, characterized in that, The catalyst is a combination of trialkylboron and onium salt.

6. The polycarbonate polyol waterproof coating according to claim 4, characterized in that, The core polyol mentioned in step (1) is trimethylolpropane or pentaerythritol.

7. The polycarbonate polyol waterproof coating according to claim 1, characterized in that, Component A also includes a filler, which is nano-silica treated with a silane coupling agent.

8. The polycarbonate polyol waterproof coating according to claim 1, characterized in that, Component B is an isocyanate, which is selected from one or more combinations of HDI, MDI, TDI or IPDI.

9. A polycarbonate polyol waterproof coating according to claim 1, characterized in that, When component A and component B are mixed, the equivalent ratio of NCO to OH is 1~1.10:

1.

10. A polycarbonate polyol waterproof coating according to claim 1 or 9, characterized in that, When the coating is used as a primer, the equivalent ratio of NCO to OH is 0.9:1; when used as an intermediate coat, the equivalent ratio is 1.0:1; and when used as a topcoat, the equivalent ratio is 1.05 to 1.10:1.