Polyurea-Based Composite Waterproofing Composition, Polyurea Resin Waterproof Coating Material Having Improved Waterproof Performance Using the Same, and Construction Method Thereof

Abstract

The present invention relates to a polyurea-based composite waterproofing composition, a polyurea resin film waterproofing material with improved waterproofing performance using the same, and a method of application thereof. More specifically, the invention relates to a polyurea-based composite waterproofing composition that improves durability, workability, and eco-friendliness by including a hydroxyl group-containing filler and an acetyl group-containing plasticizer, while also improving long-term waterproofing reliability by implementing a waterproofing structure in which a primer layer, an intermediate polyurea resin layer, and a top coating layer interact in combination, and a polyurea resin film waterproofing material using the same and a method of application thereof. The present invention provides a polyurea-based composite waterproofing composition comprising a main part comprising an isocyanate compound containing isocyanate groups and a filler having hydroxyl groups on its surface, and a curing agent part comprising an amine compound containing amine groups and a plasticizer containing acetyl groups, wherein at least a portion of the surface of the filler exists in a state where it is chemically modified by a reaction between the isocyanate groups of the isocyanate compound and the hydroxyl groups on the surface of the filler.

Description

Technology Field

[0001] The present invention relates to a polyurea-based composite waterproofing composition, a polyurea resin film waterproofing material with improved waterproofing performance using the same, and a method for applying the same. Background Technology

[0002] In general, polyurea-based coatings are widely used as waterproofing materials for construction and civil engineering structures due to their rapid curing speed and excellent mechanical and chemical resistance. In particular, polyurea-based waterproofing materials are applied to various areas such as roofs, parking lot slabs, rooftops, bridge decks, and underground structures, as they have the advantage of rapidly forming a continuous film and being applicable to substrates with complex shapes.

[0003] However, conventional polyurea coatings may be susceptible to defects such as pinholes, micropores, localized undercoating, uneven film thickness, and poor interfacial adhesion occurring during the application process, as well as cracks caused by temperature changes, repetitive loading, structural behavior, and external impacts during long-term use. If such defects or cracks occur, a pathway may be formed for external moisture to penetrate along that area into the underside of the coating or the substrate interface.

[0004] In particular, moisture that penetrates through cracks or defects can remain at the interface between the coating film and the substrate, forming a moisture trapping area, which can lead to the so-called water pocket phenomenon. These water pockets cause repeated moisture ingress and retention, and promote delamination, swelling, peeling, and interface deterioration of the coating film, thereby significantly reducing waterproofing performance and durability.

[0005] Furthermore, conventional polyurea coatings may exhibit a self-stiffening phenomenon during long-term use, in which stiffness increases and elongation decreases due to temperature changes, repeated loading, and the rearrangement of polymer chains. This phenomenon increases the likelihood of embrittlement and cracking of the coating, and ultimately acts as a factor that further exacerbates the problem of moisture penetration.

[0006] Meanwhile, conventional non-reactive inorganic fillers have low interfacial affinity with the resin matrix, making them prone to aggregation and precipitation, and limiting the improvement of interfacial adhesion with the substrate. Furthermore, if wettability to the concrete substrate is insufficient, the liquid composition may not penetrate sufficiently into the micropores and irregularities on the substrate surface, leading to pinhole formation and reduced adhesion strength.

[0007] Furthermore, in terms of eco-friendliness, existing polyurea systems often contain organic solvents or plasticizers with a high environmental burden to ensure workability and flexibility, which can lead to the emission of volatile organic compounds (VOCs) and worker safety issues.

[0008] Therefore, there is a need for a new waterproofing technology that can maintain the high-speed curing characteristics of polyurea-based coatings while comprehensively securing not only the water-blocking performance of the coating itself but also water-blocking functions at interlayer and substrate interfaces, improving long-term durability and workability, and reducing environmental burden. The problem to be solved

[0009] The present invention aims to solve the problems of the prior art described above by providing a polyurea-based composite waterproofing composition that can improve durability, workability, and eco-friendliness while maintaining the ultra-fast curing characteristics of the polyurea-based composition.

[0010] In addition, the present invention aims to provide a polyurea resin film waterproofing material with improved waterproofing performance that can achieve a double waterproofing effect in which a primer layer, an intermediate polyurea resin layer, and a top coating layer work complementarily using the above composition, thereby enabling primary waterproofing in the top coating and secondary waterproofing in the intermediate polyurea resin layer.

[0011] In addition, the present invention aims to provide a construction method for forming the above-mentioned composite waterproof structure. means of solving the problem

[0012] To achieve the above objective, according to one aspect of the present invention, a polyurea-based composite waterproofing composition is provided, comprising: a main component comprising an isocyanate compound containing isocyanate groups and a filler having hydroxyl groups on its surface; and a curing agent component comprising an amine compound containing amine groups and a plasticizer containing acetyl groups.

[0013] In the above subject section, at least some of the hydroxyl groups on the surface of the filler may react with the isocyanate groups of the isocyanate compound to form carbamate bonds (-NH-COO-). Accordingly, the filler may exist in a surface-modified state in which at least some of the organic groups derived from the isocyanate compound are chemically grafted.

[0014] After the curing agent part is mixed with the main part and cured, a reversible hydrogen bond network may be formed between the residual hydroxyl groups of the surface-modified filler and the acetyl groups of the plasticizer.

[0015] The above isocyanate compound may include a carbodiimide-modified diisocyanate, and in one embodiment, may include a carbodiimide-modified MDI (methylene diphenyl diisocyanate).

[0016] The above filler may be a reactive filler having reactive hydroxyl groups on its surface, and in one embodiment, may include hydroxyapatite.

[0017] The average particle size of the above filler may be 1 μm or less, and preferably 100 nm or less.

[0018] The above filler may be anisotropic particles, and specifically, may be in the shape of one or more of nanoribbons, nanowires, nanosheets, and nanorods.

[0019] The above filler may be included in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the total composition.

[0020] The above amine compound may include a polyetheramine having an amine group at the terminal end.

[0021] The equivalent ratio of the isocyanate group and the amine group may be 0.8 to 1.2.

[0022] The above plasticizer may be a plasticizer containing an acetyl group, and in one embodiment, may include acetyl tributyl citrate (ATBC), which is a citrate-based plasticizer.

[0023] The above plasticizer may be included in an amount of 5 to 20 parts by weight based on 100 parts by weight of the total composition.

[0024] In one embodiment, the composition may have a static contact angle of 90° or less with respect to a concrete substrate.

[0025] According to another aspect of the present invention, a polyurea resin film waterproofing material with improved waterproofing performance is provided, formed using the polyurea-based composite waterproofing composition. The film waterproofing material may be formed as a composite waterproofing system comprising a primer layer, an intermediate polyurea resin layer, and a top coating layer.

[0026] The above undercoat primer layer can perform the function of improving adhesion to the substrate and filling fine pores on the surface of the substrate.

[0027] The above intermediate polyurea resin layer is a main waterproof layer formed by the above polyurea-based composite waterproof composition and can perform a secondary waterproof function that blocks moisture movement paths.

[0028] The above-mentioned top coating layer is the uppermost layer directly exposed to the external environment and can perform a primary waterproofing function that blocks external moisture ingress first.

[0029] That is, the composite waterproofing system according to the present invention can implement a double waterproofing structure in which primary waterproofing by the top coating layer and secondary waterproofing by the intermediate polyurea resin layer act complementarily. In this case, the undercoat primer layer can improve the interfacial bonding strength and construction stability between the substrate and the waterproofing layer, thereby increasing the sustainability of the overall waterproofing performance.

[0030] According to another aspect of the present invention, a method for constructing the composite waterproofing system is provided. The construction method may include the steps of: applying a primer to a substrate to form a primer layer; applying and curing a polyurea-based composite waterproofing composition to form an intermediate polyurea resin layer; and forming a top coating layer on the intermediate polyurea resin layer. Effects of the invention

[0031] According to the present invention, durability, workability, and eco-friendliness can be improved through a polyurea-based composite waterproofing composition comprising a hydroxyl group-containing filler and an acetyl group-containing plasticizer.

[0032] In addition, since the filler acts as a reactive filler with a chemically modified surface rather than a simple filler, aggregation and precipitation are suppressed, and dispersion stability within the resin matrix can be improved.

[0033] In addition, a stress relief pathway can be provided under conditions where external load, temperature change, or repeated deformation is applied by the hydrogen bond-based intermolecular interaction structure formed between the surface-modified filler and the plasticizer, and accordingly, the magnetic stiffness and embrittlement progression of the coating film can be suppressed.

[0034] In addition, improved wettability to the concrete substrate can be advantageous for penetration into fine pores, pinhole suppression effects, and the formation of interfacial adhesion structures.

[0035] Furthermore, the polyurea resin film waterproofing material according to the present invention can be implemented as a composite waterproofing system comprising a primer layer, an intermediate polyurea resin layer, and a top coating layer, wherein the primary waterproofing by the top coating layer and the secondary waterproofing by the intermediate polyurea resin layer work together to produce an excellent double waterproofing effect.

[0036] Therefore, even if moisture enters through defects formed during the construction process or cracks that occur during use, the diffusion of moisture under the coating film and penetration into the substrate interface can be effectively suppressed, thereby reducing water pocket phenomena, lifting, swelling, peeling, and interface deterioration, and improving long-term durability. Brief explanation of the drawing

[0037] FIG. 1 is a schematic diagram illustrating a filler surface modification process according to one embodiment of the present invention. FIG. 2 is a schematic diagram showing the process of forming a polyurea matrix by the reaction of a main component and a curing agent component according to one embodiment of the present invention. FIG. 3 is a schematic diagram showing the interaction state between a modified filler and a plasticizer according to one embodiment of the present invention. FIG. 4 is a process flow diagram showing the manufacturing and construction process of a composite waterproofing composition according to one embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing a composite waterproof construction structure according to one embodiment of the present invention. Specific details for implementing the invention

[0038] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the following embodiments are merely examples to aid in understanding the present invention, and the scope of the present invention is not limited thereto. Furthermore, unless otherwise specifically defined, terms used in this specification have the meanings commonly understood by a person skilled in the art.

[0039] In this specification, “self-stiffening” refers to a phenomenon in which the physical properties of a coating film change in a direction in which its stiffness increases and its elongation decreases in response to the passage of time, temperature changes, repeated loading, or external forces after curing. Since this self-stiffening phenomenon can lead to a decrease in the flexibility of the coating film, accelerated embrittlement, and an increased possibility of cracking over the long term, it may act as a factor that reduces the durability of the waterproof coating film.

[0040] In this specification, “composite waterproofing” refers to a waterproofing concept in which multiple constituent layers or multiple waterproofing mechanisms performing different functions within a single waterproofing system act complementarily. More specifically, the composite waterproofing in the present invention may include a structure in which a base primer layer, an intermediate polyurea resin layer, and a top coating layer are laminated, and includes a concept of improving overall waterproofing performance by having each layer perform adhesion stability with the substrate, structural waterproofing function, and surface waterproofing function, either individually or together.

[0041] In this specification, “double waterproofing” refers to a structure in which primary waterproofing by a topcoat layer and secondary waterproofing by an intermediate polyurea resin layer act sequentially and complementarily. That is, it refers to a structure in which the topcoat layer, which is directly exposed to the external environment, primarily blocks the direct inflow of external moisture, and even if some moisture penetrates downward through partial damage, deterioration, construction errors, or cracks in the topcoat layer, the intermediate polyurea resin layer performs an additional waterproofing function by suppressing or blocking the movement of moisture. At this time, the undercoat primer layer can contribute to maintaining the long-term waterproofing performance of the entire laminated structure by improving interfacial adhesion between the substrate and the upper coating film and stabilizing fine pores or irregularities on the surface of the substrate.

[0042] In addition, the term “water pocket” in this specification refers to a phenomenon in which moisture penetrating from the outside is trapped and retained at the interface beneath the coating film or the substrate. Since such water pockets can cause lifting, swelling, peeling, interface deterioration, and repeated re-entry of moisture into the coating film, they are one of the major causes of reduced long-term waterproofing reliability. Therefore, it is desirable for the waterproofing structure to be designed to go beyond simply blocking moisture at the surface of the coating film, and to minimize the movement path and retention possibility even if some moisture penetrates.

[0043] First, the polyurea-based composite waterproofing composition according to the present invention is a two-component system comprising a main component (100) comprising an isocyanate compound (110) containing an isocyanate group and a filler (120) having a hydroxyl group on its surface, and a curing agent component (200) comprising an amine compound (210) containing an amine group and a plasticizer (220) containing an acetyl group. The composition is characterized in that, unlike a two-component polyurea system where the main component and the curing agent component are simply mixed and cured, the surface of the filler within the main component is modified in advance, and after curing, an intermolecular interaction structure is formed between the filler and the plasticizer. Such a structure can be advantageous for simultaneously improving dispersion stability before film formation, stress relaxation characteristics after film formation, and crack resistance during long-term use.

[0044] The main component (100) comprises an isocyanate compound (110) and a filler (120). In this case, the filler (120) may not be a simple non-reactive filler, but may act as a reactive filler having reactive hydroxyl groups on its surface. As shown in FIG. 1, the hydroxyl groups on the surface of the filler may react with the isocyanate groups of the isocyanate compound to form carbamate bonds (-NH-COO-), and accordingly, at least a portion of the surface of the filler may exist in a state chemically modified by the component derived from the isocyanate compound.

[0045] In the above-mentioned manufacturing step of the main component, the hydroxyl group on the surface of the filler and the isocyanate group of the isocyanate compound can react as shown in Reaction Scheme 1 below to form a carbamate bond.

[0046] [Reaction Equation 1]

[0047] Filler-OH + OCN-R → Filler-O-CO-NH-R

[0048] Here, Filler-OH refers to a filler having hydroxyl groups on its surface, OCN-R refers to an isocyanate compound containing isocyanate groups, and the reaction product indicates a state in which the filler surface is chemically modified by an isocyanate-derived component.

[0049] Such surface modification can serve to improve interfacial affinity between the filler and the resin component. Generally, if inorganic fillers do not have sufficient affinity with the organic polymer matrix, aggregation or precipitation is likely to occur, and stress concentration or delamination may occur at the filler-matrix interface. However, when the filler surface is chemically linked to the isocyanate component as in the present invention, the filler can be dispersed more stably within the resin system, and the filler-matrix interface can form a more continuous and stable structure even after curing. As a result, the microstructural uniformity of the coating film is improved, and the possibility of localized defects or weak points is reduced.

[0050] The above isocyanate compound (110) may include a diisocyanate or a modified product thereof, and preferably may include a carbodiimide modified diisocyanate. In one embodiment, the isocyanate compound may be a carbodiimide modified MDI (Methylene Diphenyl Diisocyanate). Carbodiimide modified MDI has excellent handling properties under practical process conditions, is advantageous for forming a relatively stable dispersion state when mixed with reactive fillers, and can rapidly form a polyurea resin network upon curing, making it suitable for waterproofing applications requiring rapid construction.

[0051] The filler (120) is not particularly limited as long as it is an inorganic filler having hydroxyl groups capable of reacting on the surface, but preferably may include hydroxyapatite. Hydroxyapatite may have functional groups capable of reacting on the surface and may be advantageous for forming interfacial interactions with the resin matrix along with structural stability characteristic of inorganic materials. In particular, the hydroxyapatite is suitable as a reactive filler required in the present invention because it not only has a simple filling effect but can exist in a surface-modified state through reaction with isocyanate and, after curing, can participate in the formation of hydrogen bonds with a plasticizer through residual hydroxyl groups.

[0052] The average particle size of the filler (120) may be 1 μm or less, and more preferably 100 nm or less. If the filler particle size is excessively large, the specific surface area decreases, which may reduce the efficiency of the surface modification reaction, reduce dispersion stability within the composition, and cause problems such as nozzle clogging or uneven application during spray application. On the other hand, if the average particle size is controlled to be below the above range, a sufficient reactionable surface area of ​​the filler can be secured, and more efficient interfacial interaction formation and uniform dispersion can be expected even at the same content. In addition, fine particles can contribute to forming a continuous microstructure more stably within the coating film.

[0053] Additionally, the filler (120) may have an anisotropic shape. For example, the filler may have one or more shapes among nanoribbons, nanowires, nanosheets, and nanorods. Such anisotropic fillers have a larger surface area per unit mass compared to spherical fillers, can increase the contact length with the resin matrix, and can improve structural connectivity between fillers. Therefore, when an external force is applied inside the coating film, a stress transfer path can be formed more continuously, and when moisture attempts to pass through the coating film, its movement path can be guided in a curved shape rather than a straight line. Consequently, this can contribute to reducing the penetration rate and diffusion efficiency of moisture, which can be advantageous for improving long-term water-blocking performance.

[0054] The content of the filler (120) may be 0.01 to 10 parts by weight based on 100 parts by weight of the total composition. If the content of the filler is too low, the effect of forming an interfacial structure due to surface modification of the filler, the effect of reinforcing the structure inside the film, and the effect of bending the moisture movement path may not be sufficiently expressed. Conversely, if the content of the filler is too high, the viscosity of the main component may increase excessively, which may reduce storage stability, mixability, and sprayability, and the uniformity of the film structure may be reduced due to the re-aggregation of the filler. Therefore, the above range may be a range that comprehensively considers reactivity, dispersibility, structural reinforcing ability, and process suitability.

[0055] The curing agent part (200) includes an amine compound (210) and a plasticizer (220) and is a component that is mixed with the main part to finally form a polyurea resin matrix. The amine compound (210) may include a polyetheramine having an amine group at the terminal end. The polyetheramine forms a urea bond through a reaction with an isocyanate compound and can impart elasticity and conformability to the coating film through flexible polyether chains. Accordingly, the amine compound may be advantageous for ensuring crack resistance and deformation conformability along with rapid curing of the polyurea resin layer.

[0056] As shown in FIG. 2, the isocyanate compound (110) of the main component (100) and the amine compound (210) of the curing agent (200) react after mixing to form urea bonds, and accordingly, a polyurea matrix (300) can be formed inside the coating film.

[0057] When the above main component and curing agent are mixed, the isocyanate group of the isocyanate compound and the amine group of the amine compound react as shown in Reaction Scheme 2 below to form a urea bond, and accordingly, a polyurea matrix can be constructed.

[0058] [Reaction Equation 2]

[0059] R-NCO + H2N-R' → R-NH-CO-NH-R'

[0060] The above reaction can proceed at a rapid reaction rate, and as a result, a continuous polyurea resin network can be formed within a short period of time.

[0061] The above polyurea matrix functions as a structural framework for the intermediate polyurea resin layer and can provide high mechanical strength, elasticity, and water resistance. In addition, since the filler exists in a surface-modified state rather than simply dispersed, the possibility of separation at the filler-matrix interface is reduced, and structural stability can be improved even under repeated loading or temperature change conditions.

[0062] The equivalent ratio of the isocyanate group to the amine group may be 0.8 to 1.2. If the equivalent ratio is excessively low, the possibility of residual unreacted amine components increases, which may lead to surface adhesion, uneven curing, or reduced durability. Conversely, if the equivalent ratio is excessively high, the crosslinking density increases excessively, which may result in the formation of an overly rigid structure of the coating film and a reduced ability to follow repeated loads or the micro-behavior of the structure, thereby increasing the likelihood of cracking. Therefore, the above range may be a desirable range that considers the balance of curing completeness, flexibility, and long-term durability.

[0063] The plasticizer (220) may be a plasticizer containing an acetyl group, preferably a citrate-based plasticizer. In this specification, “acetyl group-containing plasticizer” may mean a plasticizer that contains an acetyl group and / or an ester carbonyl group within the molecule and can form hydrogen bonding interactions with the hydroxyl group on the surface of the filler.

[0064] In one embodiment, the plasticizer may be acetyl tributyl citrate (ATBC). Since ATBC has a relatively low viscosity, it can reduce the initial viscosity of the composition and contribute to improving fluidity and spreadability during spraying or application. Furthermore, the plasticizer is not limited to being a simple viscosity-reducing component but can act as a functional component capable of forming hydrogen bonding interactions with residual hydroxyl groups on the filler surface through the acetyl groups within its molecular structure.

[0065] As illustrated in FIG. 3, the acetyl or carbonyl groups of the plasticizer (220) can form hydrogen bonding interactions with the hydroxyl groups remaining on the surface of the surface-modified filler (120) within the polyurea matrix (300) after curing. In FIG. 3, (a) may exemplarily represent the surface state of the surface-modified filler, (b) the structure of the plasticizer, and (c) the state of hydrogen bonding interactions between the modified filler and the plasticizer. Accordingly, a reversible intermolecular interaction network mediated by the filler and involving the plasticizer as a bonding point can be formed inside the film.

[0066] After curing, hydrogen bonding interactions such as the reaction scheme 3 below may be formed between the residual hydroxyl groups of the surface-modified filler and the acetyl or carbonyl groups of the plasticizer.

[0067] [Reaction Model 3]

[0068] Filler-OH … O=C-Plasticizer

[0069] The above interaction is a reversible intermolecular interaction distinct from covalent bonding, and since it can be partially dissociated upon the application of an external force and reformed after the external force is removed, it can contribute to stress relief and structural stabilization within the coating film.

[0070] In particular, the interaction structure between the filler and the plasticizer described above does not merely act in the direction of softening the coating film, but can form a balanced structure that imparts flexibility along with sufficient strength. While conventional plasticization improves the flexibility of the coating film, it may potentially reduce mechanical strength or long-term stability; however, in the present invention, the interaction between the functional groups on the surface of the filler and the functional groups of the plasticizer allows for the simultaneous imparting of structural continuity and reversible bonding within the coating film. Therefore, it is possible to simultaneously improve initial workability and durability after curing.

[0071] Additionally, the plasticizer (220) can contribute to lowering the viscosity of the composition and appropriately controlling the gelation time. Accordingly, the composition in a liquid state can exhibit better wettability on the surface of the substrate and can penetrate more smoothly into the micropores, irregularities, and microcracks of the surface. This improvement in penetration is not limited to simple ease of application, but can also increase the actual contact area between the substrate and the coating film, reduce the possibility of pinhole formation due to air trapping, and consequently contribute to forming a more dense interfacial adhesion structure.

[0072] The content of the above plasticizer (220) may be 5 to 20 parts by weight based on 100 parts by weight of the total composition. If the plasticizer content is too low, the viscosity reduction effect, the flexibility imparting effect, and the effect of forming an interaction network with the filler may not be sufficiently expressed. Conversely, if the plasticizer content is too high, the proportion of non-reactive low-molecular-weight components increases, which may reduce mechanical strength, heat resistance, or shape retention. Therefore, the above range may be a range that considers the balance of workability, flexibility, structural stability, and long-term physical properties.

[0073] The polyurea-based composite waterproofing composition according to the present invention can be designed so that the static contact angle with respect to a concrete substrate is 90° or less. When the liquid composition exhibits a contact angle of 90° or less with respect to the substrate, the composition wets the surface of the substrate more effectively and can spread more easily into micropores, capillary structures, and irregularities. As a result, the actual contact area between the substrate and the composition increases, air trapping is reduced during film formation, and the possibility of pinholes or localized uncoated areas is reduced. Furthermore, this excellent wettability can contribute to improving interfacial stability by allowing the undercoat primer layer or intermediate layer to bond more tightly with the substrate.

[0074] Meanwhile, the present invention relates not only to the composition itself but also to a composite waterproof construction structure formed using it. More specifically, the waterproof structure according to the present invention may include a primer layer (400) formed on a substrate, an intermediate polyurea resin layer (500) formed on top thereof, and a top coating layer (600) formed on top thereof. Such a three-layer structure is not a simple laminated structure, but a functional composite waterproof system designed so that each layer performs a different role.

[0075] The undercoat primer layer (400) can function as a base layer to improve adhesion between the substrate and the subsequently formed intermediate layer. More specifically, the undercoat primer layer can penetrate into the surface micropores and irregularities of concrete, mortar, metal, or other substrates to be constructed, thereby stabilizing the surface and improving interfacial bonding strength with the intermediate polyurea resin layer formed on top. Accordingly, the possibility of interlayer delamination, interfacial lifting, or localized delamination is reduced, and it can contribute to improving the integrity of the entire laminated structure even when subjected to repeated loads or temperature changes during long-term use.

[0076] The intermediate polyurea resin layer (500) can function as a main structural waterproof layer formed by the polyurea-based composite waterproof composition of the present invention. The intermediate layer is based on a polyurea matrix formed by an isocyanate-amine reaction and may have a composite structure including a surface-modified filler and a hydrogen bond network between the filler and the plasticizer. Accordingly, the intermediate layer can simultaneously secure mechanical strength, elasticity, crack-following properties, and moisture movement inhibition functions, and can function as a secondary waterproof layer against moisture that passes through the top layer or enters through damaged areas of the top layer.

[0077] The top coating layer (600) can function as the top layer that is directly exposed to the external environment. The top coating layer can function as a primary waterproof layer that protects the intermediate layer in an environment where it is directly exposed to ultraviolet rays, friction, contaminants, chemicals, and moisture, while also blocking the direct inflow of external moisture. Therefore, under normal usage conditions, the top coating layer acts as the primary barrier against external moisture penetration, and if partial damage or microcracks occur in the top coating layer, the intermediate polyurea resin layer underneath performs the waterproofing function again, thereby realizing a double waterproof structure.

[0078] That is, in the composite waterproofing system according to the present invention, the undercoat primer layer is responsible for interfacial adhesion and substrate stabilization functions, the intermediate polyurea resin layer is responsible for structural and material secondary waterproofing functions, and the topcoat coating layer is responsible for surface water barrier and external environment blocking. Through such a laminated structure, local defects, microcracks, or surface deterioration, which were problematic in single-layer coatings, can be prevented from immediately leading to overall waterproofing failure, and consequently, long-term waterproofing reliability can be improved.

[0079] In addition, the composite waterproofing construction method according to the present invention may include, as illustrated in FIG. 4, a first step (S10) of preparing a main component by mixing an isocyanate compound and a filler having hydroxyl groups on its surface to modify at least a portion of the surface of the filler; a second step (S20) of preparing a curing agent component by mixing an amine compound and a plasticizer containing acetyl groups; a third step (S30) of forming an intermediate polyurea resin layer (500) by mixing the main component and the curing agent component after forming a primer layer (400) on a substrate (700); and a fourth step (S40) of forming a top coating layer (600) on the intermediate polyurea resin layer (500).

[0080] The first step (S10) above is preferably performed under an inert atmosphere to suppress side reactions caused by moisture, and may be performed, for example, under a nitrogen atmosphere. This is to prevent the isocyanate compound from reacting with moisture in the air to cause an increase in viscosity, gelation, or a decrease in reactivity. In addition, the filler can be uniformly dispersed through a stirring or dispersion process in the above step, and if necessary, a high-speed stirrer, a homomixer, an ultrasonic disperser, or a combination thereof may be used.

[0081] In the second step (S20) above, a single-phase curing agent part can be prepared by uniformly mixing an amine compound and a plasticizer. This step can be performed at room temperature, and if necessary, a heated stirring or vacuum degassing process may be performed in parallel. When the curing agent part prepared as above is mixed with the main part in the third step (S30), the amine compound reacts with the isocyanate to form a polyurea matrix (300), and the plasticizer participates in forming an interaction structure with the filler after curing.

[0082] In the third step (S30) above, a primer layer (400) can be formed by first applying a primer to the surface of the substrate (700). Subsequently, an intermediate polyurea resin layer (500) can be formed by mixing and spraying or applying a main component and a curing agent component onto the primer layer (400). Immediately after mixing, the reaction between the isocyanate compound and the amine compound proceeds rapidly to form a polyurea matrix (300), and at the same time, a hydrogen bond network can be formed between the residual hydroxyl groups on the surface of the filler and the acetyl or carbonyl groups of the plasticizer. As a result, the formed intermediate layer can be formed not as a simple cured resin layer, but as a composite waterproof layer having both structural reinforcement and stress relief functions.

[0083] In the above fourth step (S40), a topcoat coating agent may be applied to the upper surface of the intermediate polyurea resin layer (500) to form a topcoat coating layer (600). The topcoat coating layer (600) may function as a surface barrier layer against external moisture, ultraviolet rays, friction, and contaminants.

[0084] In actual construction, first, dust, foreign substances, oil, and a weak layer on the surface of the substrate (700) can be removed, and then a primer can be applied to form a primer layer (400). Subsequently, an intermediate polyurea resin layer (500) can be formed by mixing and spraying or applying the main component and the curing agent component of the present invention onto the primer layer (400). Afterward, a top coating agent can be applied to the upper part of the intermediate polyurea resin layer (500) to form a top coating layer (600), thereby completing a composite waterproofing system consisting of a primer layer (400), an intermediate polyurea resin layer (500), and a top coating layer (600).

[0085] Hereinafter, an embodiment of the present invention will be described in more detail.

[0086] 70 parts by weight of carbodiimide-modified diisocyanate and 1.0 parts by weight of hydroxyapatite with an average particle size of 200 nm were mixed under a nitrogen atmosphere. Mixing was performed for 30 minutes using a high-speed stirrer (2,000 rpm). During this process, the hydroxyapatite particles were uniformly dispersed within the isocyanate compound, and simultaneously, some of the hydroxyl groups on the filler surface reacted with the isocyanate groups to form carbamate bonds, thereby producing a main component in which the filler surface was chemically modified. At this time, the equivalent ratio of the isocyanate group to the amine group, calculated based on the NCO content of the isocyanate compound and the amine number of the polyetheramine, was adjusted to be approximately 1.0.

[0087] Meanwhile, 20 parts by weight of polyetheramine and 9 parts by weight of acetyl tributyl citrate were stirred at room temperature for 10 minutes to prepare a uniformly mixed curing agent.

[0088] Subsequently, after pre-treating the surface of the concrete substrate (700), a primer was applied to form a primer layer (400). Then, an intermediate polyurea resin layer (500) was formed by mixing and applying the main component and the hardener component in a 1:1 volume ratio using a two-component high-pressure spray device. Immediately after mixing, a reaction between the isocyanate compound and the amine compound proceeded to form a polyurea matrix (300), and at the same time, hydrogen bonds were formed between the residual hydroxyl groups of the surface-modified filler and the acetyl or carbonyl groups of the plasticizer, thereby establishing an interaction structure within the coating film. Subsequently, a topcoat coating agent was applied on the intermediate polyurea resin layer (500) to form a topcoat coating layer (600). As a result, a composite waterproofing system consisting of a primer layer (400), an intermediate polyurea resin layer (500), and a top coating layer (600) was realized, and a structure was formed capable of primary waterproofing by the top layer and secondary waterproofing by the intermediate layer.

[0089] In the composite waterproofing system formed as described above, the topcoat layer can perform a primary blocking function against external moisture, contaminants, and UV exposure under normal usage conditions, and even if microcracks, wear, or localized damage occur in the topcoat layer, the underlying intermediate polyurea resin layer can function as a secondary waterproofing layer by suppressing the movement of moisture again. In addition, the undercoat primer layer contributes to maintaining adhesion between the substrate and the intermediate layer, thereby reducing the possibility of interfacial delamination or peeling even during long-term use. Therefore, the present invention can improve the reliability and durability of waterproofing performance compared to simple film waterproofing materials.

[0091] The above description is merely about some preferred embodiments that can be implemented by the present invention, and therefore the scope of the present invention should not be interpreted as being limited to the above embodiments, and all modifications within the technical concept of the present invention and its equivalent scope shall be included within the scope of the present invention. Explanation of the symbols

[0092] 100: Main topic 110: Isocyanate compounds 120: Filler 200: Hardener section 210: Amine compounds 220: Plasticizer 300: Polyurea Matrix 400: Undercoat primer layer 500: Intermediate polyurea resin layer 600: Top coating layer 700: Entry

Claims

Claim 1 A polyurea-based composite waterproofing composition comprising a main part comprising an isocyanate compound containing isocyanate groups and hydroxyapatite having hydroxyl groups on its surface, and a curing agent part comprising an amine compound containing amine groups and a plasticizer containing acetyl groups, wherein the hydroxyapatite is characterized in that at least a portion of its surface exists in a chemically modified state by forming a carbamate bond (-NH-COO-) through a reaction between the isocyanate group of the isocyanate compound and the hydroxyl group on the surface of the hydroxyapatite. Claim 2 delete Claim 3 A polyurea-based composite waterproofing composition according to claim 1, characterized in that after the curing agent part is mixed and cured with the main part, a hydrogen bonding interaction is formed between the residual hydroxyl group of the surface-modified hydroxyapatite and the acetyl group or carbonyl group of the plasticizer. Claim 4 A polyurea-based composite waterproof composition according to claim 1, characterized in that the isocyanate compound comprises a carbodiimide-modified diisocyanate. Claim 5 delete Claim 6 A polyurea-based composite waterproofing composition according to claim 1, characterized in that the average particle size of the hydroxyapatite is 1 μm or less. Claim 7 A polyurea-based composite waterproofing composition according to claim 1, characterized in that the hydroxyapatite is anisotropic particle. Claim 8 A polyurea-based composite waterproofing composition according to claim 7, wherein the anisotropic particles are one or more selected from the group consisting of nanoribbons, nanowires, nanosheets, and nanorods. Claim 9 A polyurea-based composite waterproofing composition according to claim 1, characterized in that the hydroxyapatite is included in an amount of 0.01 to 10 parts by weight per 100 parts by weight of the total composition. Claim 10 A polyurea-based composite waterproof composition according to claim 1, wherein the plasticizer comprises a citrate-based plasticizer, and the plasticizer is included in an amount of 5 to 20 parts by weight per 100 parts by weight of the total composition. Claim 11 A polyurea-based composite waterproof composition according to claim 10, wherein the plasticizer comprises acetyl tributyl citrate. Claim 12 A polyurea-based composite waterproofing composition according to claim 1, characterized in that the equivalent ratio of the isocyanate group to the amine group is 0.8 to 1.

2. Claim 13 A polyurea-based composite waterproof composition according to claim 1, characterized in that the amine compound comprises polyetheramine. Claim 14 A polyurea-based composite waterproofing composition according to claim 1, characterized in that when the liquid mixture of the main component and the curing agent component is applied, the contact angle with respect to the concrete substrate is 90˚ or less. Claim 15 A composite waterproofing construction method using a polyurea-based composite waterproofing composition according to any one of claims 1, 3 to 4, and 6 to 14, comprising: a step of forming a primer layer by applying a primer on a substrate; a step of forming an intermediate polyurea resin layer by mixing and applying a main component and a curing agent component on the primer layer; and a step of forming a top coating layer on the intermediate polyurea resin layer. Claim 16 A composite waterproofing construction method according to claim 15, wherein the step of forming the intermediate polyurea resin layer comprises: a step of preparing a main component by mixing an isocyanate compound with hydroxyapatite having hydroxyl groups on its surface to modify at least a portion of the surface of the hydroxyapatite; a step of preparing a curing agent component by mixing an amine compound with a plasticizer containing acetyl groups; and a step of mixing the main component and the curing agent component to form a polyurea resin layer. Claim 17 A composite waterproofing construction method according to claim 16, characterized in that the step of manufacturing the main component is performed under a nitrogen atmosphere. Claim 18 A composite waterproofing construction structure comprising: a substrate; a primer layer formed on the substrate; an intermediate polyurea resin layer formed on the primer layer and formed from a polyurea-based composite waterproofing composition according to any one of claims 1, 3 to 4, and 6 to 14; and a topcoat coating layer formed on the intermediate polyurea resin layer. Claim 19 A composite waterproof construction structure according to claim 18, characterized in that the topcoat layer performs a primary waterproofing function that blocks the direct inflow of external moisture, and the intermediate polyurea resin layer performs a secondary waterproofing function that blocks the movement of moisture that passes through the topcoat layer or penetrates through construction defects or cracks. Claim 20 A composite waterproof construction structure according to claim 18, characterized in that the undercoat primer layer penetrates into the micropores or irregularities of the substrate surface to form an interfacial bond between the substrate and the intermediate polyurea resin layer. Claim 21 A composite waterproof construction structure according to claim 18, wherein the intermediate polyurea resin layer comprises a polyurea matrix formed by the reaction of an isocyanate compound and an amine compound, and comprises a hydrogen bond network between the surface-modified hydroxyapatite and the plasticizer. Claim 22 A composite waterproofing construction structure according to claim 18, characterized in that the composite waterproofing construction structure is applied to a concrete structure, a building rooftop, a roof, a parking lot slab, a bridge deck, or an underground structure.

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