KR102443584B1 - Polyurethane composition for multi-functional top coat layer and method for forming a water-proof structure - Google Patents

Abstract

A multi-functional polyurethane composition includes a main agent part and a curing agent part. The main agent part, based on 100 parts by weight of the curing agent part, comprises: 100 to 120 parts by weight of acrylic polyol; 10 to 50 parts by weight of alkyd polyol; 10 to 60 parts by weight of polyester polyol; 20 to 40 parts by weight of a viscosity modifier; 40 to 60 parts by weight of a ceramic hollow pigment; 0.1 to 2 parts by weight of aerogel; 0.1 to 5 parts by weight of zeolite; and 0.1 to 2 parts by weight of white charcoal. The polyurethane composition forms a waterproof coating having multifunctional properties such as heat insulating performance, heat shielding performance, and antibacterial performance.

Description

Polyurethane composition for multifunctional topcoat and waterproof structure construction method using same

The present invention relates to a waterproof structure construction, and more particularly, to a polyurethane composition for a multifunctional topcoat and a waterproof structure construction method using the same.

In general, the room temperature curing type paint composition applied to coating film waterproofing agents and flooring materials is exposed to the atmosphere and cured by air and moisture, cured by exposure to heat or ultraviolet rays, and cured by chemical reaction of the main agent and the curing agent. There are anticorrosive coating compositions.

The top coat of the conventionally used epoxy paint composition is a curing method according to the active reaction of the main curing agent by a chemical reaction, and instantaneous heat is generated when the main material and the curing agent are mixed. Although it has excellent mechanical properties, such as odor and long-term service life, various problems such as yellowing of weather resistance, loss of gloss, and cracks have been found, and improvement is required.

A urethane topcoat composition may be used as an alternative to supplement and improve the problems of the epoxy coating composition described above. The urethane topcoat composition is particularly excellent in weathering resistance to yellowing, and problems of loss of gloss and occurrence of cracks do not occur. In addition, it is cured in the form of a chemical structural reaction with acrylic polyol and isocyanate prepolymer and is maintained in a non-yellowing form due to the combination of dense crosslinking and physicochemical properties. have it

The conventionally performed urethane topcoat resin composition generally serves to protect from water, temperature, climate, physical factors, heat or ultraviolet rays. In addition, there is an urgent need to create a beneficial environment harmless to the human body and energy-saving effects related to heat such as seasonal factors in summer and winter and rapidly changing climate changes due to the lack of functionalities of condensation and mold, insulation performance, and heat shielding performance. Unlike general urethane topcoat resin compositions, the waterproof resin composition for topcoat with multifunctional performance of the present invention provides multifunctional thermal insulation performance, heat shielding performance, antibacterial properties, antifungal resistance, and far-infrared emissivity to provide a comfortable environment and space. There is a need for the development of a coating film waterproofing resin composition for a top coat having functional performance.

One object of the present invention is to provide a polyurethane composition for top coating having excellent multifunctional performance of heat insulation performance, heat shielding performance, antibacterial property, antifungal resistance, and far-infrared emissivity.

Another object of the present invention is to provide a waterproof construction method using the polyurethane composition for top coating.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and may be variously expanded without departing from the spirit and scope of the present invention.

A multifunctional polyurethane composition according to exemplary embodiments of the present invention for achieving the above-described object of the present invention includes a main part and a curing agent part. The main part, 100 to 120 parts by weight of an acrylic polyol, 10 to 50 parts by weight of an alkyd polyol, 10 to 60 parts by weight of a polyester polyol, 20 to 40 parts by weight of a viscosity modifier, 40 to 40 parts by weight of a ceramic hollow pigment based on 100 parts by weight of the curing agent part 60 parts by weight, 0.1 to 2 parts by weight of airgel, 0.1 to 5 parts by weight of zeolite, and 0.1 to 2 parts by weight of white coal.

According to one embodiment, the acrylic polyol is obtained by reacting styrene, acrylic acid, ethylhexyl acrylate, butyl acrylate and hydroxyl ethyl methacrylate. The alkyd polyol is obtained by reacting palm oil (coconut fatty acid), phthalic anhydride, pentaerythritol and trimethylol propane. The polyester polyol is obtained by reacting phthalic anhydride, terephthalic acid, isophthalic acid, adipic acid, trimethylolpropane and neopentyl glycol.

According to an embodiment, the ceramic hollow pigment has a particle diameter of 5 to 10 μm, the zeolite has a particle diameter of 2 to 5 μm, and the white coal has a particle diameter of 2 to 5 μm.

According to an embodiment, the curing agent part includes an aliphatic isocyanate.

According to one embodiment, the content of the functional powder component including the airgel, the zeolite and the white charcoal is 3 to 5 parts by weight based on 100 parts by weight of the curing agent part.

The waterproof structure construction method according to an embodiment of the present invention comprises the steps of directly coating a polyurea composition for undercoating on a concrete base to form an undercoating layer, and coating the polyurea composition for intermediatecoating on the undercoating film to form an intermediate layer. Forming and coating the multifunctional polyurethane composition on the intermediate layer to form a top coat layer.

As described above, according to exemplary embodiments of the present invention, it is possible to form a waterproof coating film having multi-functionality such as thermal insulation performance, heat shielding performance, and antibacterial performance.

1 to 3 are cross-sectional views illustrating a waterproof structure construction method according to an embodiment of the present invention.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate that a feature, number, step, operation, element, or a combination thereof described in the specification exists, but one or more other features or numbers , it should be understood that it does not preclude the possibility of the presence or addition of steps, operations, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Polyurethane composition for multifunctional topcoat

subject part

The polyurethane composition according to an embodiment of the present invention may be a two-component composition including a main part and a curing agent part.

The main part may include a polyol, and the curing agent part may include an isocyanate.

The polyol may include at least one of an alkyd polyol, a polyester polyol, a polyester-modified acrylic polyol, and an acrylic polyol. The reactivity of a polyol is affected by the electronegativity of the hydroxyl group, and the higher the electronegativity, the faster the reaction. Electronegativity depends on the proximity of the electron donor or acceptor groups of the hydroxyl group bond. In most organic resins, heterogeneous elements are not present in the resin, but if an electron donor such as an alkyl or oxygenated group is in close proximity to a hydroxyl group, it has a deactivation effect on the reactivity.

The isocyanate may include aromatic isocyanate or aliphatic isocyanate. For example, the isocyanate includes MDI (Methylene diphenyl diisocyanate), TDI (Toluene diisocyanate), HDI (Hexamethylene diisocyanate, hexamethylene diisocyanate), IPDI (Isophorone diisocyanate, isophorone diisocyanate), etc. can do.

According to an embodiment, the isocyanate may include an aliphatic diisocyanate such as HDI or IPDI. When an isocyanate including an aromatic ring is used, yellowing may occur due to exposure to ultraviolet rays or the like.

For example, as the isocyanate, Bayer's Desmodur WH12MDI, Desmodur I-IPDI (isophorone diisocyanate), Desmodur N-3300, Desmodur N-3600, Desmodur N-3800, Desmodur Z4470, HDI trimer, etc. may be used.

According to an embodiment, the curing agent part may further include a viscosity modifier (organic solvent) such as toluene and xylene. In addition, the curing agent part may further include 1 to 5% by weight of an additive such as an antifoaming agent, if necessary.

For example, the curing agent part may include 55 to 80% by weight of the isocyanate, 15 to 40% by weight of the viscosity modifier, and 0.1 to 5% by weight of the additive.

According to an embodiment, the polyol may include an acrylic polyol, an alkyd polyol, and a polyester polyol. For example, the main part may include 100 to 120 parts by weight of the acrylic polyol, 10 to 50 parts by weight of the alkyd polyol, and 10 to 60 parts by weight of the polyester polyol based on 100 parts by weight of the curing agent part. Preferably, the main part may include 100 to 120 parts by weight of the acrylic polyol, 20 to 30 parts by weight of the alkyd polyol, and 20 to 30 parts by weight of the polyester polyol based on 100 parts by weight of the curing agent part.

According to an embodiment, the acrylic polyol may be obtained by reacting styrene, acrylic acid, ethylhexyl acrylate, butyl acrylate and hydroxyl ethyl methacrylate, and the glass transition temperature may be 10 to 40°C. In addition, the alkyd polyol may be obtained by reacting palm oil (coconut fatty acid), phthalic anhydride, pentaerythritol and trimethylol propane. In addition, the polyester polyol may be obtained by reacting phthalic anhydride, terephthalic acid, isophthalic acid, adipic acid, trimethylolpropane and neopentyl glycol.

When the polyol of the above composition is used, a coating film having high weather resistance and glossiness and excellent light reflection effect can be obtained.

The main part may further include a pigment, a ceramic hollow pigment, an airgel, a zeolite, and white coal.

The pigment is for hiding and imparting color to the coating film, for example, carbon black, titanium dioxide (TiO2), iron oxide yellow, iron oxide red, phthalocyanine. Green (Phthalocyanine green) and the like may be included.

The content of the pigment may be 1 to 5 parts by weight based on 100 parts by weight of the curing agent. When the content of the pigment is out of the above range, it may be difficult to provide a desired color or hide a coating film and color expression.

The ceramic hollow pigment may impart thermal insulation performance and heat shielding performance to the coating film. Accordingly, it is possible to prevent dew condensation, and it is possible to increase the heating efficiency. In addition, ceramics are more effective in forming a heat insulating layer and a thermal barrier because they have a property of reflecting heat as well as transferring heat less.

For example, the ceramic hollow pigment may have a particle diameter of about 5 to 10 μm, and the content may be 40 to 60 parts by weight based on 100 parts by weight of the curing agent. If the particle diameter of the ceramic hollow pigment is too small, heat insulation/heat shielding performance may be deteriorated, and if too large, smoothness of the waterproof coating film may be deteriorated. In addition, when the content of the ceramic hollow pigment is excessive, the viscosity of the main part may excessively increase or precipitates may occur.

For example, the main component of the airgel may be silicon oxide (SiO2), and may have a form in which fibers (one ten thousandth the thickness of hair) are loosely entangled. Air molecules may be included between the fibers, and for example, air may occupy 98% of the total volume.

The airgel, like the ceramic hollow pigment, can improve the insulating performance and heat shielding performance of the coating film, and can also improve the flame retardancy of the coating film.

For example, the content of the airgel may be 0.1 to 2 parts by weight based on 100 parts by weight of the curing agent. When the content of the airgel is excessive, the viscosity of the main part may be excessively increased.

The zeolite is an aluminosilicate mainly composed of silicon, aluminum, and oxygen, and also contains a small amount of a metal such as titanium, tin, zinc, etc., and is a microporous solid that can be used as a molecular sieve. Zeolite has excellent antibacterial and antifungal resistance and improves the durability of the waterproof coating film by improving the heat resistance of the coating film.

For example, the content of the zeolite may be 0.1 to 5 parts by weight based on 100 parts by weight of the curing agent, and the particle size may be 2 to 5 μm. When the content of the zeolite is excessive, precipitation may occur in the curing agent part and the viscosity may excessively increase.

For example, the white coal may be charcoal white coal. The white charcoal adsorbs harmful gases, and the micropores of the charcoal rapidly adsorb moisture and diverge when dry to provide a humidity control function. In addition, white charcoal can provide comfort in a space where a waterproof coating film is installed by emitting far-infrared rays.

In addition, the white charcoal has excellent deodorization and antibacterial functions, so that it is possible to increase the usability of the waterproof coating film indoors.

For example, the content of the white charcoal may be 0.1 to 2 parts by weight based on 100 parts by weight of the curing agent, and the particle size may be 2 to 5 μm. When the content of the white coal is out of the above range, precipitation may occur in the curing agent part and the viscosity may increase excessively, and the color (black) may be visually recognized.

In the curing agent part, the content of the functional powder component including the airgel, the zeolite and the white charcoal may be 1 to 10 parts by weight, preferably 3 to 5 parts by weight, based on 100 parts by weight of the curing agent part. When the content of the functional powder component is excessive, gloss, weather resistance, elongation, etc. may be reduced.

The main part may further include a viscosity modifier (organic solvent) such as toluene and xylene. In addition, the main part may further include a dispersing agent, an antifoaming agent, a catalyst, and the like, if necessary.

For example, the content of the viscosity modifier may be 20 to 40 parts by weight based on 100 parts by weight of the curing agent, and the content of the dispersant, the antifoaming agent and the catalyst may be 0.1 to 5 parts by weight.

How to construct a waterproof structure

1 to 3 are cross-sectional views illustrating a waterproof structure construction method according to an embodiment of the present invention.

Referring to FIG. 1 , an undercoating layer 23 is formed on the base surface of the substrate 10 . The base 10 may be concrete or the like. Before forming the undercoating layer 23, foreign substances and latency present on the base 10 may be removed by a grinding process or may be cleaned by high-pressure water jet (water jet) of 200 bar or more. The concrete substrate may have micropores (PH, pinholes) resulting from material properties.

The undercoating layer 23 may be formed of a polyurea composition.

According to an embodiment, as the polyurea composition, the polyurea composition for undercoating a waterproofing film described in the applicant's application (Application No. 10-2021-0137677) may be used.

According to an embodiment, the polyurea composition for undercoating may be sprayed onto the base material 10 by a polyurea-only coating device.

For example, the polyurea composition for undercoating may be sprayed under low-temperature, low-pressure conditions or high-temperature and high-pressure conditions. For example, the low-temperature and low-pressure conditions may be from about 30° C. to about 50° C., the discharge pressure may be from about 100 psi to about 500 psi, and the high-temperature and high pressure conditions may be from about 60° C. to about 70° C., and the discharge pressure is about 1,500 psi to about 2,000 psi.

For example, the polyurea composition for undercoating may be sprayed under low temperature and low pressure conditions in order to control the curing rate or to minimize scattered dust. In addition, it is possible to suppress fine floating particles that may occur during painting (to minimize the impact on operator safety and surrounding structures), and to form a flat top surface with high airtightness with the substrate and to finish the polyurea intermediate layer to be subsequently painted. You can keep the surface beautiful. However, embodiments of the present invention are not limited thereto, and the polyurea composition for undercoating may form an excellent undercoating film even under high temperature and high pressure conditions.

According to an embodiment, the curing agent part and the main part of the polyurea composition for undercoating may be sprayed after collision mixing at high temperature and high pressure in the spray gun 30 . However, the present invention is not limited thereto, and the curing agent part and the main part of the polyurea composition for undercoating may be screw-mixed by a static mixer in a low temperature and low pressure state.

For example, the mixing ratio of the main part and the curing agent part may be about 1:1 by volume, and the molar ratio of the reactive groups (amine groups and hydroxyl groups) of the main part and the isocyanate groups of the curing agent part is about 1.0:1.1 to about 1.0:1.2 can be

The polyurea composition for undercoating can sufficiently fill the micropores (PH) of the base material 10 by having a low curing rate and high fluidity. Therefore, it is possible to form the undercoat layer without the conventional polyurethane base adjustment layer.

The cured undercoating layer 23 may exhibit a gray color due to a whitening phenomenon and a black colorant included in the curing agent part. When the discharge ratio of the mixture of the curing agent part and the main part is different, a black part or a white part may appear. Accordingly, as the operator quickly recognizes whether the undercoat layer 23 is defective, immediate repair is possible.

Referring to FIG. 2 , an intermediate layer 24 is formed on the undercoat layer 23 .

A multifunctional polyurea composition may be used to form the intermediate layer 24 . The multifunctional polyurea composition for intermediate use may include a main part and a curing agent part.

The main part of the multifunctional polyurea composition for intermediate use may include an isocyanate prepolymer and a flame retardant. The isocyanate prepolymer has an isocyanate group (-OCN) at the terminal, and may be obtained by reaction of a polyol with an isocyanate.

According to one embodiment, the isocyanate prepolymer is a mixture of 2,2′-MDI, 2,4′-MDI and 4,4′-MDI (MDI isomer mixture) 30 to 70% by weight based on the total weight of the reactant, and It can be obtained by reacting 30 to 70% by weight of polypropylene glycol.

Specifically, the isocyanate prepolymer, 2,2'-MDI 10 to 20% by weight, 2,4'-MDI 10 to 20% by weight, and 4,4'-MDI 20 to 30% by weight based on the total weight of the reactant, and It can be obtained by reacting 30 to 60% by weight of polypropylene glycol. More preferably, the isocyanate prepolymer, 2,2'-MDI 15 to 20% by weight, 2,4'-MDI 15 to 20% by weight, and 4,4'-MDI 23 to 27% by weight based on the total weight of the reactant And it can be obtained by reacting 35 to 50% by weight of polypropylene glycol. In addition, the NCO% content of the main part (isocyanate prepolymer) may be 12 to 20%, preferably 14 to 16%.

According to one embodiment, the flame retardant may include tris (2-chloroethyl) phosphate (Tris (2-chloroethyl) phosphate).

According to an embodiment, the main part may include 85 to 99% by weight of the isocyanate prepolymer and 1 to 15% by weight of the flame retardant. Preferably, the main part may include 88 to 95% by weight of the isocyanate prepolymer and 5 to 12% by weight of the flame retardant. More preferably, the main part may include 90 to 95 wt% of the isocyanate prepolymer and 5 to 10 wt% of the flame retardant.

The curing agent part of the multifunctional polyurea composition for intermediate use is polyether amine, crosslinking agent (chain extender), pigment (Pigment), ceramic hollow pigment, airgel (aerogel), zeolite (Zeolite), white charcoal, flame retardant and UV stabilizer may include.

The polyether amine may be an aliphatic amine, for example, may have a number average molecular weight of 1,000 to 3,000. The crosslinking agent may be an aromatic amine. For example, the crosslinking agent may include diethyltoluenediamine (DETDA) or the like.

For example, the content of the polyether amine may be 50 to 85 wt%, and the content of the crosslinking agent may be 10 to 30 wt%, based on the total weight of the curing agent part. Preferably, the content of the polyether amine may be 55 to 75% by weight, and the content of the crosslinking agent may be 20 to 25% by weight.

The pigment, the ceramic hollow pigment, the airgel, the zeolite, the white charcoal, and the flame retardant may be substantially the same as described above. In addition, the content of the functional powder component including the ceramic hollow pigment, the airgel, the zeolite and the white charcoal may be about 1 to 10% by weight, preferably 3 to 5% by weight, based on the total weight of the curing agent part. have. When the content of the functional powder component is excessive, mechanical properties of the coating film may be deteriorated.

The intermediate layer 24 may be formed by a polyurea-only coating device, and may be formed under high temperature and high pressure conditions. For example, the high temperature and high pressure conditions are about 65° C. to about 75° C. (hose heating temperature), the spray chamber is about 0.42 inches to about 0.60 inches, and the discharge pressure (spray spray pressure) is about 2,000 psi to about It can be 3,000 psi. In addition, the thickness of the coating film may be about 1,000 μm to about 2,000 μm.

Referring to FIG. 3 , a top coat layer 26 is formed on the intermediate layer 24 . For example, the topcoat layer 26 may be formed using the previously-described multifunctional polyurethane composition for topcoating. The polyurethane composition may be applied using a roller or airless,

Hereinafter, through specific examples and experiments, the polyurethane composition according to the present invention and the mechanical performance and functionality of the coating film formed using the same will be described in detail.

Example

Synthesis Example 1 - Synthesis of acrylic polyol

Put xylene and n-butyl acetate in the reactor, raise the re-flux temperature to 95~100℃, then styrene monomer, acrylic acid), ethylhexyl acrylate, butyl acrylic Rate, hydroxyethyl methacrylate, polymerization initiator TBPB (t-butyl perbenzoate), and BPO (benzoyl peroxide) were added dropwise for 3 hours, and 5% of the initial initiator was added after 1 hour. After reacting for 3 to 4 hours, a radical polymer was prepared. For each resin, the hydroxyl value and the theoretical tg value calculated by the fox formula were 10℃ and 40℃, and the viscosity of the prepared resin was similarly designed to 60wt% of the resin solid content, and xylene/n-butyl acetate was added in an 8/2 ratio. diluted with

Synthesis Example 2 - Alkyd Polyol Synthesis

After putting coconut fatty acid, phthalic anhydride, pentaerithritol, and tri-methylol propane in the reactor, the temperature was gradually increased to 220℃ while injecting nitrogen gas (N ₂ ), and then xylene was added. Measure the viscosity and acid value while refluxing, and when the gardner (25℃) VW, Z1-Z3 acid value reaches 3~9mg KOH/g, collect the xylene in a vacuum and cool it to make the resin solid content to 60wt% xylene/n -Butyl acetate was diluted at a ratio of 8/2.

Synthesis Example 3 - Polyester Polyol Synthesis

Put phthalic anhydride, terephthalic acid, isophthalic acid, and adipic acid in the reactor, add trimethylol propane and neopentyl glycol as polyhydric alcohols, and gradually increase the temperature to 220°C while blowing nitrogen gas until the acid value is 2 mg KOH/g or less. did it Then, polyacid was added at 160 ° C or lower, and the temperature was gradually increased to 220 ° C. Then, the xylene was refluxed to maintain a certain viscosity and acid value, and then the xylene was recovered in a vacuum and cooled, and the solid content of the resin was 60 wt. %, xylene/n-butyl acetate was diluted at a ratio of 8/2.

According to Table 1 below, the polyurethane compositions of Examples 1 to 5 were prepared.

As a result of evaluating the coating film formed using the compositions of Examples 1 to 5, in the case of Example 1, the occurrence of stickiness on the surface due to the influence of unreacted substances and the coating film properties such as impact resistance and water resistance were reduced, and in the case of Example 2, elongation rate This was lowered. As a result of observing the physical properties of Example 3, it was confirmed that the weather resistance and gloss were excellent and the light reflection effect was excellent.

With reference to the results of Table 1, the polyurethane compositions of Examples 6 to 10 were prepared according to Table 2 below, the main part and the curing agent part were mixed, and then a dry coating film was applied to a thickness of 200 µm using an airless coating machine and dried at room temperature. After drying for one week, glossiness, weather resistance, water resistance and impact resistance test (KS M 5000), antibacterial test (JIS Z 2801), anti-fungal resistance test (ASTM G-21), solar reflectance test (JIS K 5602), far-infrared rays Emissivity test (KFIA-FI-1005) to evaluate the physical properties (requested by an accredited testing institute) are listed in Table 3.

Referring to Table 3, it was confirmed that the heat shielding performance, antibacterial performance, antifungal resistance performance, and far-infrared emissivity were excellent as the composite functional powder and ceramic hollow pigment increased, but when the content was excessive (Example 10), elongation, It was confirmed that weather resistance and gloss were significantly reduced.

Although described with reference to exemplary embodiments of the present invention as described above, those of ordinary skill in the art may vary the present invention within the scope without departing from the spirit and scope of the present invention described in the claims below. It will be understood that modifications and changes can be made to

The polyurethane composition and waterproof construction method according to exemplary embodiments of the present invention may be used for waterproof construction of various structures.

Claims (6)

including a main part and a curing agent part;
The main part, 100 to 120 parts by weight of an acrylic polyol, 10 to 50 parts by weight of an alkyd polyol, 10 to 60 parts by weight of a polyester polyol, 20 to 40 parts by weight of a viscosity modifier, 40 to 40 parts by weight of a ceramic hollow pigment based on 100 parts by weight of the curing agent part A multifunctional polyurethane composition comprising 60 parts by weight, 0.1 to 2 parts by weight of airgel, 0.1 to 5 parts by weight of zeolite, and 0.1 to 2 parts by weight of white coal. According to claim 1, wherein the acrylic polyol is obtained by reacting styrene, acrylic acid, ethylhexyl acrylate, butyl acrylate and hydroxyl ethyl methacrylate,
The alkyd polyol is obtained by reacting palm oil (coconut fatty acid), phthalic anhydride, pentaerythritol and trimethylol propane,
The polyester polyol is a multifunctional polyurethane composition, characterized in that obtained by reacting phthalic anhydride, terephthalic acid, isophthalic acid, adipic acid, trimethylolpropane and neopentyl glycol. The method of claim 1,
The ceramic hollow pigment has a particle diameter of 5 to 10 μm, the particle diameter of the zeolite is 2 to 5 μm, and the white charcoal has a particle diameter of 2 to 5 μm. The multifunctional polyurethane composition according to claim 1, wherein the curing agent part comprises an aliphatic isocyanate. The multifunctional polyurethane composition according to claim 1, wherein the content of the functional powder component including the airgel, the zeolite and the white charcoal is 3 to 5 parts by weight based on 100 parts by weight of the curing agent. forming an undercoat layer by directly coating the polyurea composition for undercoating on a concrete base surface;
forming an intermediate layer by coating a polyurea composition for intermediate use on the undercoat layer; and
A waterproof structure construction method comprising the step of forming a top coat layer by coating the multifunctional polyurethane composition of any one of claims 1 to 5 on the intermediate layer.

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