Composition for concrete protection and kit

Abstract

To provide a composition for concrete protection and a kit, having high concrete protection performance.SOLUTION: A composition for concrete protection includes an aqueous emulsion of a polycarbonate-based urethane resin. The polycarbonate-based urethane resin has a glass transition temperature of -40°C or more and -15°C or less, a strength at break of 35 MPa or more and 100 MPa or less, and an elongation at break of 350% or more and 1000% or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a composition and a kit for concrete protection.

Background Art

[0002] As a technique for preventing concrete from peeling off from a concrete body constituting a structure, a technique of applying a transparent composition for concrete protection to the surface of the concrete body has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, as a composition for concrete protection, it is preferable to be based on an aqueous emulsion of a resin from the viewpoint of environmental hygiene. However, a conventional composition based on an aqueous emulsion of a resin has insufficient concrete protection performance.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a composition and a kit for concrete protection having high concrete protection performance.

Means for Solving the Problems

[0006] As a result of intensive studies to achieve the above object, the present inventor has found that a composition and a kit for concrete protection having a predetermined composition and characteristics have high concrete protection performance, and has completed the present invention.

[0007] That is, the present invention is as follows. [1] An aqueous emulsion of a polycarbonate-based urethane resin, wherein the polycarbonate-based urethane resin has a glass transition temperature of -40°C or higher and -15°C or lower, a breaking strength of 35 MPa or higher and 100 MPa or lower, and an elongation at break of 350% or higher and 1000% or lower, A composition for concrete protection. [2] The composition according to [1], having thixotropy. [3] The composition according to [1] or [2], having a thixotropy index of 2.0 or higher. [4] The composition according to any one of [1] to [3], for application to concrete via an epoxy-based aqueous sealer. [5] The composition according to any one of [1] to [4], further comprising a first thickener which is a (meth)acrylic polymer. [6] The composition according to [5], further comprising a second thickener which is a nonionic polymer. [7] The composition according to [1], being transparent. [8] A coating film forming kit for concrete protection, comprising the composition according to any one of [1] to [7] and an epoxy-based aqueous sealer. [9] The coating film formed from the aqueous sealer and the composition has an adhesion strength of the surface coating material measured in accordance with JSCE-K 531-2013, the standard specification for concrete, of 3.0 N / mm 2 or more, The kit according to [8].

[10] The coating film formed from the aqueous sealer and the composition for concrete protection has a maximum load at a displacement of 10 mm or more measured in accordance with the pull-out test for peeling prevention, Test Method 424-2011, Part 4, Structural Relationship Test Methods of NEXCO, of 1.5 kN or more. The kit according to [8] or [9].

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a concrete protection composition and a kit having high concrete protection performance.

Brief Description of the Drawings

[0009]

Figure 1

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail with reference to the drawings as necessary. In the drawings, the same reference numerals will be given to the same elements, and redundant descriptions will be omitted. Also, the positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios.

[0011] The concrete protection composition of the present embodiment is used to protect the concrete by applying it to the surface of the concrete. For example, in the present embodiment, by applying the concrete protection composition of the present embodiment to the surface of the concrete body constituting the structure to form a protective coating film, peeling of the concrete from the concrete body is prevented.

[0012] Here, the structure and type of the "structure" are not particularly limited, and examples include civil engineering structures such as tunnels and bridges, apartment houses such as apartments and condominiums, and architectural structures such as commercial facilities.

[0013] FIG. 1 is a schematic cross-sectional view showing the application of the concrete protection composition of the present embodiment to the surface of the concrete body 110 to form a protective coating film 120. A sealer layer may exist between the concrete body 110 and the protective coating film 120 to enhance the adhesion and / or adhesiveness between the two. The protective coating film 120 contains a solidified product of the concrete protection composition of the present embodiment.

[0014] [Concrete body] The concrete body 110 means a member made of concrete (for example, reinforced concrete, prestressed concrete, etc.), and includes, for example, concrete beam members, column members, wall members, floor members, cladding members, exterior finish members, and interior finish members. The concrete body 110 is, for example, a member constituting a structure.

[0015] [Protective coating film] The protective coating film 120 is formed on the surface of the concrete body 110 and suppresses the peeling of concrete from the concrete body. The protective coating film 120 includes a solidified product of the concrete protection composition of the present embodiment. Hereinafter, the concrete protection composition of the present embodiment will be described.

[0016] (Concrete protection composition) The concrete protection composition of the present embodiment includes an aqueous emulsion of a polycarbonate-based urethane resin, and the polycarbonate-based urethane resin has a glass transition temperature of -40°C or higher and -15°C or lower, a breaking strength of 35 MPa or higher and 100 MPa or lower, and an elongation at break of 350% or higher and 1000% or lower.

[0017] As demonstrated in the examples described later, the concrete protection composition of the present embodiment can achieve high concrete protection performance by having the above configuration. Since the concrete protection composition is used to form the protective coating film 120 for preventing the peeling of concrete, it is preferably transparent and can form a transparent protective coating film 120. If a transparent protective coating film 120 can be formed, the surface state of the concrete body 110 can be visually recognized even after the film formation, which is preferable from the viewpoint of repair and inspection of the concrete body 110. For example, when the concrete protection composition is applied to the concrete body 110 at a basis weight of 1.0 kg / m 2 or more and 1.2 kg / m 2 or less to form the protective coating film 120, it is preferable that the surface of the concrete body 110 can be visually recognized.

[0018] (Aqueous Emulsion of Polycarbonate-based Urethane Resin) Since the concrete protection composition uses an aqueous emulsion of a polycarbonate-based urethane resin, it has high resistance to water and light and is excellent in water resistance and weather resistance. Since concrete bodies are usually exposed to rain and wind, excellent water resistance and weather resistance enable high concrete protection performance to be achieved over a long period. In addition, since the polycarbonate-based urethane resin has high elasticity, the concrete protection performance is improved. Furthermore, since the polycarbonate-based urethane resin has high flame retardancy, the protective coating 120 is excellent in fire resistance. Also, since the main component of the concrete protection composition, the polycarbonate-based urethane resin, is contained as an aqueous emulsion, it is an aqueous paint and does not contain an organic solvent or contains only a small amount even if it does. Therefore, when forming the protective coating 120, the concrete protection composition has reduced odor and is preferable in terms of environmental hygiene.

[0019] The aqueous emulsion of the polycarbonate-based urethane resin is an emulsion containing a solvent mainly composed of water and particles of the polycarbonate-based urethane resin dispersed in the solvent. This aqueous emulsion is obtained by emulsion polymerization of a polycarbonate polyol and a polyisocyanate in a solvent mainly composed of water.

[0020] The average particle diameter of the polycarbonate-based urethane resin particles is not particularly limited as long as it can maintain the state of the emulsion. For example, it may be 0.01 μm or more and 1.5 μm or less, may be 0.02 μm or more and 1.0 μm or less, or may be 0.03 μm or more and 0.5 μm or less. The average particle diameter of the resin particles is measured by a laser diffraction particle size distribution measuring device (for example, a concentrated particle size analyzer, manufactured by Otsuka Electronics Co., Ltd., product name "FPAR-1000").

[0021] The glass transition temperature of the polycarbonate-based urethane resin is -40°C or higher and -15°C or lower, preferably -38°C or higher and -18°C or lower, more preferably -35°C or higher and -20°C or lower. Since the glass transition temperature is -15°C or lower, the elasticity of the protective coating film 120 can be maintained even at low temperatures, and high concrete protection performance can be maintained. Also, since the glass transition temperature is -40°C or higher, the concrete protection performance of the protective coating film at normal temperature is high. The glass transition temperature of the resin can be measured using a dynamic viscoelasticity measuring device (for example, manufactured by TA Instruments, product name "RSA3") or a thermomechanical analyzer (for example, manufactured by Hitachi High-Technologies Corporation, product name "TMA-7000").

[0022] In this embodiment, the glass transition temperature of the polycarbonate-based urethane resin can be controlled by adjusting the molecular weight of the polycarbonate-based urethane resin and introducing a modifying group.

[0023] The breaking strength of the polycarbonate-based urethane resin is 35 MPa or higher and 100 MPa or lower, preferably 35 MPa or higher and 90 MPa or lower, more preferably 35 MPa or higher and 80 MPa or lower. When the breaking strength is within the above range, the protective coating film 120 has high concrete protection performance. In this embodiment, the breaking strength of the resin is measured by pulling the resin using a tensile testing machine (for example, manufactured by Shimadzu Corporation, product name "Autograph AG-I").

[0024] The elongation at break of the polycarbonate-based urethane resin is 350% or higher and 1000% or lower, preferably 350% or higher and 900% or lower, more preferably 350% or higher and 800% or lower. When the elongation at break is within the above range, the protective coating film 120 has high concrete protection performance. In this embodiment, the elongation at break of the resin is measured by pulling the resin using a tensile testing machine (for example, manufactured by Shimadzu Corporation, product name "Autograph AG-I").

[0025] The 100% modulus of the polycarbonate-based urethane resin is preferably 2 MPa or more and 50 MPa or less, more preferably 3 MPa or more and 40 MPa or less, and even more preferably 4 MPa or more and 30 MPa or less. When the 100% modulus is within the above range, the concrete protection performance of the protective coating 120 is further improved. In this embodiment, the 100% modulus of the resin means the stress required to stretch the resin by 100%, and is measured by stretching the resin using a tensile testing machine (for example, "Autograph AG-I" manufactured by Shimadzu Corporation). Note that the units "MPa" and "N / mm 2 " are equivalent.

[0026] In this embodiment, the 100% modulus, breaking strength, and elongation at break of the polycarbonate-based urethane resin can be controlled by adjusting the molecular weight of the polycarbonate-based urethane resin and introducing a modifying group. Also, the 100% modulus, breaking strength, and elongation at break of the polycarbonate-based urethane resin may be adjusted by combining two or more polycarbonate-based urethane resins.

[0027] The polycarbonate-based urethane resin used in this embodiment may be produced by a conventionally known method or a commercially available product may be used. Examples of commercially available products include, for example, Evafanol HA-50C (trade name, manufactured by Nikkawa Chemical Co., Ltd.), Takelac W-635 (trade name, manufactured by Mitsui Chemicals, Inc.), Eternacol UW-3100 (trade name, manufactured by Ube Industries, Ltd.), Eternacol UW-5502 (trade name, manufactured by Ube Industries, Ltd.), Eucote UX-485 (trade name, manufactured by Sanyo Chemical Industries, Ltd.), WBR-2101 (trade name, manufactured by Daisheng Fine Chemical Co., Ltd.), Melsi 5030 (trade name, manufactured by Toyo Polymer Co., Ltd.), Melsi 5045 (trade name, manufactured by Toyo Polymer Co., Ltd.), and R-4000 (trade name, manufactured by Kusumoto Chemicals, Ltd.). The polycarbonate-based urethane resin is used alone or in combination of two or more.

[0028] The content of the polycarbonate-based urethane resin is preferably 20% by mass or more and 70% by mass or less, more preferably 25% by mass or more and 60% by mass or less, and even more preferably 30% by mass or more and 50% by mass or less, based on the solid content (total of components excluding the solvent) contained in the composition. When the content of the polycarbonate-based urethane resin is within the above range, the viscosity of the concrete protection composition becomes a suitable range, and the workability during the formation of the protective coating film tends to be further improved.

[0029] (Thixotropy) The concrete protection composition preferably has thixotropy. In the present embodiment, thixotropy refers to a property in which the viscosity is relatively high in a steady state (for example, a state where no shear stress is applied), the viscosity decreases when a shear stress is applied, and the viscosity returns to the original value when the application of the shear stress is stopped. When the concrete protection composition has thixotropy, the viscosity decreases when the composition is applied to the concrete body 110, making it easier to apply. On the other hand, after application, the viscosity increases, preventing dripping. As a result, the protective coating film 120 obtained through the drying of the applied composition is formed evenly on the concrete body 110 and has high adhesion to the concrete body 110, so it tends to have good concrete protection performance.

[0030] Thixotropy is represented by the thixotropy index TI measured by a dynamic viscoelasticity measuring device (for example, a BH type viscometer manufactured by Toki Sangyo Co., Ltd.). In the present embodiment, the thixotropy index TI is defined by the following formula (1). TI = (viscosity at a liquid temperature of 23°C and a rotational speed of 2 rpm) / (viscosity at a liquid temperature of 23°C and a rotational speed of 20 rpm) …(1)

[0031] The closer the thixotropy index TI is to 1, the more it exhibits the behavior of a Newtonian liquid, and the larger the thixotropy index TI, the higher the thixotropy.

[0032] In the present embodiment, the thixotropy index TI of the concrete protection composition is preferably greater than 1, more preferably 2.0 or more. When the thixotropy index TI is within the above range, the difference between the low viscosity when applying the concrete protection composition to the concrete body 110 and the high viscosity after application becomes larger, which is preferable. From the same viewpoint, the thixotropy index TI is more preferably 3.0 or more, even more preferably 4.0 or more, and still more preferably 5.0 or more. The upper limit of the thixotropy index TI is not particularly limited, but the thixotropy index TI may be, for example, 8.0 or less, or 7.0 or less.

[0033] In the present embodiment, the thixotropy index TI of the concrete protection composition can be controlled, for example, by adjusting the average particle diameter of the polycarbonate-based urethane resin or adding a thickener.

[0034] (Viscosity) The viscosity of the concrete protection composition is not particularly limited, but for example, at 23°C, it is preferably 10 Pa·s or more and 60 Pa·s or less, more preferably 15 Pa·s or more and 55 Pa·s or less, and even more preferably 20 Pa·s or more and 40 Pa·s or less. When the viscosity is within the above range, it tends to be easy to adjust the thickness of the protective coating film 120 and improve the workability during the formation of the protective coating film 120. The viscosity of the concrete protection composition is measured by a dynamic viscoelasticity measuring device (for example, a BH type viscometer manufactured by Toki Sangyo Co., Ltd.).

[0035] In the present embodiment, the viscosity of the concrete protection composition can be made within the above range by adjusting the content of the solvent and the type and content of the thickener with respect to the total amount of the composition.

[0036] (Thickener) The concrete protection composition preferably further contains a thickener from the viewpoint of adjusting thixotropy and viscosity and improving workability.

[0037] The thickener is not particularly limited. For example, cellulose compounds such as carboxymethyl cellulose, methyl cellulose, and hydroxypropyl cellulose, their ammonium salts or alkali metal salts; polycarboxylic acids such as (meth)acrylic polymers and modified (meth)acrylic polymers, their alkali metal salts; polyvinyl alcohol-based polymers such as polyvinyl alcohol, modified polyvinyl alcohol, and ethylene-vinyl alcohol copolymers; urethane resins other than polycarbonate-based urethane resins such as polyether polyol-based urethane resins; polyamide-based polymers; inorganic particles such as silica particles and alumina particles, etc. may be mentioned. The thickener may be used alone or in combination of two or more. In this specification, "(meth)acrylic" means including both "acrylic" and "methacrylic". For example, a (meth)acrylic polymer may be an acrylic polymer or a methacrylic polymer.

[0038] Among them, (meth)acrylic polymers such as (meth)acrylic polymers and modified poly(meth)acrylic polymers, and nonionic polymers such as polyvinyl alcohol-based polymers, methyl cellulose, and urethane resins are preferable as the thickener.

[0039] The composition for concrete protection preferably contains a first thickener which is a (meth)acrylic polymer and a second thickener which is a nonionic polymer. The first thickener is preferably a non-alkali thickening type (meth)acrylic polymer and preferably a modified (meth)acrylic polymer.

[0040] Examples of commercially available thickeners include Adekanol UH-420 (trade name, manufactured by ADEKA), Disparon AQ-001 (trade name, manufactured by Kusumoto Chemicals), Primar ASE-60 (trade name, manufactured by Tosoh Corporation), Disparon AQ633E (trade name, manufactured by Kusumoto Chemicals), SN Thickeners 660T (trade name, manufactured by San Nopco), Aerosil COK84 (trade name, manufactured by Nippon Aerosil Co., Ltd.), etc.

[0041] As the content of the thickener, for example, it may be 0.01% by mass or more and 10% by mass or less, 0.01% by mass or more and 10% by mass or less, 0.05% by mass or more and 8.0% by mass or less, 0.1% by mass or more and 6.0% by mass or less, based on the total amount of the composition.

[0042] (Other components) Since the composition for concrete protection contains an aqueous emulsion of a polycarbonate-based urethane resin, the solvent in the composition is mainly water. Therefore, the odor when forming the protective coating film 120 is reduced, which is preferable from the viewpoint of environmental hygiene. In the present embodiment, the solvent refers to a liquid in the composition other than the resin component. The composition for concrete protection may contain a solvent other than water, such as an organic solvent or a film-forming aid described later. The organic solvent is not particularly limited, and examples thereof include hydrocarbons, ketones, alcohols, acetic acid esters, and glycol ethers. The organic solvent is used alone or in combination of two or more.

[0043] From the viewpoint of environmental hygiene, the content of the organic solvent other than the film-forming aid in the total amount of the composition for concrete protection is preferably 15% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, still more preferably 3% by mass or less, and even still more preferably 1% by mass or less. Also, from the same viewpoint, the content of the organic solvent including the film-forming aid in the total amount of the composition for concrete protection is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less.

[0044] The composition for concrete protection may contain additives such as a binder, a curing aid, a film-forming aid, an ultraviolet absorber, and an infrared absorber as components other than the above-described components.

[0045] The binder is not particularly limited as long as it can be used as a binder for an aqueous emulsion. Examples thereof include resins such as acrylic styrene resins, acrylic urethane resins, acrylic silicone resins, and modified polyester urethane resins. The binder may be used alone or in combination of two or more kinds.

[0046] The curing aid is not particularly limited. Examples thereof include aqueous isocyanate curing agents, polycarbodiimide curing agents, oxazoline curing agents, melamine curing agents, polyethyleneimine curing agents, aziridine curing agents, zirconium curing agents, and epoxy curing agents. The curing aid may be used alone or in combination of two or more kinds.

[0047] The film-forming aid is not particularly limited as long as it can assist the film-forming property of the aqueous emulsion. Examples thereof include methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, butyl carbitol, dipropylene glycol methyl ether acetate, texanol, and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate. The film-forming aid may be used alone or in combination of two or more kinds.

[0048] The ultraviolet absorber is not particularly limited as long as it can absorb ultraviolet rays. For example, salicylic acid derivatives such as methyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate; aromatic ketones such as 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, and 4-dodecyloxy-2-hydroxybenzophenone; triazole derivatives such as 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)benzotriazole, and 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole; acrylic acid derivatives such as 2'-ethylhexyl 2-cyano-3,3-diphenylacrylate; and inorganic compounds such as zinc oxide, zirconium oxide, cerium oxide, iron oxide, and titanium oxide. The ultraviolet absorber may be used alone or in combination of two or more.

[0049] The infrared absorber is not particularly limited as long as it can absorb infrared rays. For example, cyanine compounds, naphthalocyanine compounds, phthalocyanine compounds, anthraquinone compounds, naphthoquinone compounds, diimonium compounds, polymethine compounds, phthalide compounds, ITO (In2O3-TiO2 system), ATO (ZnO-TiO2 system), tin-containing compounds, antimony-containing compounds, tin-antimony oxides, and dithiol metal complexes. The infrared absorber may be used alone or in combination of two or more.

[0050] The concrete protection composition of this embodiment may further contain additives such as coloring agents, antifoaming agents, antioxidants, deodorants, antibacterial agents, antifungal agents, and fragrances, as long as it does not inhibit the solution of the problems of the present invention.

[0051] In the concrete protection composition, the content of each of the above additives may independently be 0.01% by mass or more and 15% by mass or less based on the total amount of the concrete protection composition.

[0052] (Mesh body) In addition to the solidified product of the concrete protection composition, the protective coating 120 may contain a member for further suppressing the peeling of concrete. Examples of such a member include a mesh body composed of fibers. The mesh body is held in the protective coating 120 by the concrete protection composition and is used to reinforce the protective coating 120.

[0053] The mesh body may be, for example, a knitted fiber thread. The fiber thread may be, for example, a resin thread such as vinylon and polyester.

[0054] When the protective coating 120 includes a mesh body, there is a tendency to maintain the protective performance of the protective coating 120 while reducing the usage amount of the concrete protection composition.

[0055] (Method for forming protective coating) The protective coating 120 can be formed by applying the concrete protection composition of the present embodiment to the concrete body 110 and drying and solidifying it. The concrete protection composition may be applied to the surface of the concrete body 110 through a sealer layer described later. Further, when the protective coating 120 includes a mesh body, after applying the concrete protection composition to the concrete body 110, the mesh body is arranged, and then the concrete protection composition is applied again on the mesh body and dried and solidified, so that the mesh body can be arranged inside the protective coating 120.

[0056] As a method for applying the concrete protection composition, various methods such as air spray coating, airless spray coating, dip treatment coating, brush coating, screen printing, spray coating, trowel application, and roller coating can be used.

[0057] As a method for drying the concrete protection composition, it is not particularly limited, and natural drying may be used, or heat drying by heating the composition may be used. In the case of heat drying, in order to prevent the components in the composition from decomposing, the heating temperature is preferably 150 °C or lower, and more preferably 100 °C or lower. From the viewpoint of reducing the environmental load, natural drying is preferred as the drying method.

[0058] The application and drying of the concrete protection composition may be repeated two or more times as a set. By repeating two or more times, the thickness of the protective coating film 120 can be increased, and the concrete protection performance can be further enhanced. Alternatively, the thickness of the protective coating film 120 may be increased by performing multiple applications without a drying process.

[0059] Note that the surface of the concrete body 110 may be cleaned prior to the step of applying the sealer described later or the concrete protection composition. The cleaning method is not particularly limited, and it may be high-pressure cleaning in which water is sprayed at high pressure.

[0060] The amount of the concrete protection composition applied per application is, for example, preferably 0.1 kg / m 2 or more and 2.0 kg / m 2 or less, more preferably 0.2 kg / m 2 or more and 1.5 kg / m 2 or less, and even more preferably 0.3 kg / m 2 or more and 1.0 kg / m 2 or less. When the application amount per application is 2.0 kg / m 2 or less, the formed protective coating film 120 tends to be less likely to crack. Also, when the application amount per application is 0.1 kg / m 2 or more, the workability is further improved.

[0061] The total amount of the application amount of the concrete protection composition is, for example, preferably 0.8 kg / m 2 or more and 2.0 kg / m 2 or less, more preferably 1.0 kg / m 2 or more and 1.5 kg / m2 It is more preferable that it is as follows.

[0062] The basis weight of the protective coating film 120 is preferably 0.2 kg / m 2 or more and 1.5 kg / m 2 or less, more preferably 0.3 kg / m 2 or more and 1.0 kg / m 2 or less, still more preferably 0.4 kg / m 2 or more and 0.8 kg / m 2 or less. When the basis weight is 1.5 kg / m 2 or less, the transparency of the protective coating film 120 is further improved. Further, when the basis weight is 0.2 kg / m 2 or more, better concrete protection performance can be imparted.

[0063] [Sealer layer] In FIG. 1, it is preferable that a sealer layer exists between the concrete body 110 and the protective coating film 120. The sealer layer has a role of enhancing the adhesion and / or adhesiveness between the concrete body 110 and the protective coating film 120.

[0064] From the viewpoint of enhancing the balance of the affinity with the concrete body 110 and the affinity with the protective coating film 120, the sealer layer is preferably formed of an epoxy-based aqueous sealer. The epoxy-based aqueous sealer is a sealer containing an epoxy resin whose main solvent is water.

[0065] Epoxy-based waterborne sealants may be one-component sealants containing an epoxy resin whose curing reaction proceeds by drying of the solvent, or may be two-component sealants composed of a first agent containing an epoxy resin prepolymer and a second agent containing a curing agent. For two-component sealants, the first agent and the second agent are mixed immediately before forming the sealant layer, and the mixed composition is applied to the concrete body 110 for use. The epoxy resin prepolymer is not particularly limited as long as it contains two or more epoxy groups per molecule. Also, the curing agent is not particularly limited as long as it is a molecule having a functional group that reacts with an epoxy group, and examples thereof include a curing agent having an amino group and a curing agent having a carboxyl group.

[0066] The above waterborne sealant may be produced by a conventionally known method or a commercially available product may be used.

[0067] The coating amount of the sealant is not particularly limited as long as the adhesion between the concrete body 110 and the protective coating film 120 can be enhanced, but it is preferably 0.01 kg / m 2 or more and 1.0 kg / m 2 or less, more preferably 0.02 kg / m 2 or more and 0.9 kg / m 2 or less, and even more preferably 0.03 kg / m 2 or more and 0.7 kg / m 2 or less.

[0068] As a method for applying the sealant, for example, various methods such as air spray coating, airless spray coating, dip treatment coating, brush painting, screen printing, spray coating, trowel application, and roller coating can be used.

[0069] The method for drying the sealant is not particularly limited, and it may be natural drying or heat drying by heating the sealant. In the case of heat drying, the heating temperature is preferably 150 °C or lower, and more preferably 100 °C or lower, so that the components in the sealant do not decompose. From the viewpoint of reducing the environmental load, natural drying is preferable as the drying method.

[0070] [Physical properties] In this embodiment, since the above-described composition for concrete protection is used, the protective coating film 120 has high adhesion to the concrete body 110. The strength of adhesion of the protective coating film 120 to the concrete body 110 (the adhesion strength of the surface coating material measured in accordance with the Standard Specification for Concrete JSCE-K 531-2013) is 2.0 N / mm 2 or more, 2.5 N / mm 2 or more, 3.0 N / mm 2 or more, or 3.0 N / mm 2 or more is preferable. Here, it is preferable to have a sealer layer between the protective coating film 120 and the concrete body 110.

[0071] The adhesion strength of the surface coating material measured in accordance with the Standard Specification for Concrete JSCE-K 531-2013 is measured by the following method. First, a protective coating film is formed on the concrete body (at this time, it is preferable that the protective coating film is formed on the concrete body via a sealer layer). Next, a tensile jig is attached to the protective coating film using an adhesive and left standing for 24 hours. Then, cuts are made on the four sides of a 40×40 mm square around the jig, and the jig is pulled in the vertical direction to obtain the maximum tensile load.

[0072] Also, the protective coating film 120 has an adhesion strength of the surface coating material measured in accordance with the Standard Specification for Concrete JSCE-K 531-2013 (test method for test specimens after alkali resistance test) with respect to the concrete body 110 of 2.0 N / mm 2 or more, 2.5 N / mm 2 or more, 3.0 N / mm 2 or more, or 3.0 N / mm 2 or more is preferable.

[0073] The adhesion strength of the surface coating material measured in accordance with the Standard Specification for Concrete JSCE-K 531-2013 (test method for test specimens after alkali resistance test) is measured by the same method as the above test method after leaving the protective coating film in a saturated calcium hydroxide solution for 28 days.

[0074] In this embodiment, since the above-described composition for concrete protection is used, the protective coating film 120 has high concrete protection performance. The maximum load at a displacement of 10 mm or more measured in accordance with the pull-out test method for anti-peeling in Test Method 424-2011 of NEXCO Test Method, Part 4, Structural Relationship Test Method is preferably 1.2 kN or more, 1.5 kN or more, 1.8 kN or more, or 2.0 kN or more.

[0075] The maximum load at a displacement of 10 mm or more measured in accordance with the pull-out test method for anti-peeling in Test Method 424-2011 of NEXCO Test Method, Part 4, Structural Relationship Test Method is measured by the following method. First, with the test piece supported at both ends, a known loading device is used to load the test piece through a cylindrical pressure plate inserted into a through-hole provided on the back surface of the test piece. Next, the above loading is repeated while marking the peeling range for each displacement amount of the punching displacement. Then, the loading load (punching strength) at a punching displacement of 10 mm or more is measured.

[0076] [Kit] This embodiment also provides a kit for forming a protective coating film for concrete, which includes the above-described composition for concrete protection and an epoxy-based aqueous sealer. Thereby, a protective coating film 120 with high concrete protection performance can be easily formed on the concrete body 110. The kit may further include tools for applying the sealer and / or the composition for concrete protection, such as a roller, a spray, and a brush.

[0077] As described above, the embodiments for carrying out the present invention have been explained, but the present invention is not limited to the above embodiments. The present invention can be variously modified without departing from the gist thereof.

Example

[0078] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0079] [Measurement Method of Physical Properties of Resin] In the examples, physical properties such as the 100% modulus, breaking strength, and elongation at break of the resin were measured by pulling the resin using a tensile testing machine (manufactured by Shimadzu Corporation, product name "Autograph AG-I"). The above measurements were carried out in accordance with Japanese Industrial Standard (JIS K 6251:2017) using a dumbbell-shaped No. 3 sample.

[0080] [Measurement Method for Physical Properties of Concrete Protection Composition] In the examples, the viscosity and thixotropy index TI of the concrete protection composition were measured at 23°C under specific rotation conditions using a dynamic viscoelasticity measuring device (BH type viscometer manufactured by Toki Sangyo Co., Ltd.). The thixotropy index TI was calculated according to the above formula (1) by measuring the viscosity at a rotation speed of 2 rpm and the viscosity at a rotation speed of 20 rpm. The viscosity was measured at a rotation speed of 2 rpm.

[0081] The elasticity of the protective coating film formed from the concrete protection composition was evaluated according to the following criteria. Having a breaking strength of 20 MPa or more and an elongation at break of 200% or more: ○ Having only either a breaking strength of 20 MPa or more or an elongation at break of 200% or more: △ Having a breaking strength of less than 20 MPa and an elongation at break of less than 200%: ×

[0082] The water resistance of the protective coating film formed from the concrete protection composition was confirmed by forming the protective coating film on a glass substrate and immersing it in water for 7 days. The water resistance was evaluated according to the following criteria. No peeling was observed in the protective coating film: ○ Part of the protective coating film peeled off: △ The protective coating film peeled off: ×

[0083] The low-temperature characteristics of the protective coating film formed from the concrete protection composition were evaluated according to the following criteria. The glass transition temperature of the resin is less than -10°C: ○ The glass transition temperature of the resin is less than 0°C: △ The glass transition temperature of the resin is 0°C or more: ×

[0084] The weather resistance of the protective coating film formed from the concrete protection composition is measured in accordance with the Concrete Standard Specification JSCE-K 511-2013. Specifically, a protective coating film is formed on a concrete body, and it is irradiated with a xenon arc lamp or a sunshine carbon arc lamp for 3000 hours or 2000 hours, and the weather resistance is evaluated according to the following criteria. No change in appearance and no whitening were observed in the protective coating film: ○ Either a change in appearance or whitening was observed in a part of the protective coating film: △ Either a change in appearance or whitening was observed in the protective coating film: ×

[0085] The adhesion strength of the protective coating film formed from the concrete protection composition was measured in accordance with the Concrete Standard Specification JSCE-K 531-2013. First, a tensile jig was attached to the protective coating film using an adhesive and left standing for 24 hours. Then, cuts were made on the four sides of a 40×40 mm square around the jig, and the jig was pulled in the vertical direction to obtain the maximum tensile load. And the adhesion strength was evaluated according to the following criteria. The maximum tensile load is 3.0 N / mm 2 or more: ○ The maximum tensile load is 3.0 N / mm 2 less than: ×

[0086] The adhesion strength after the alkali resistance test of the protective coating film formed from the concrete protection composition was measured in accordance with the Concrete Standard Specification JSCE-K 531-2013. First, the protective coating film was left in a saturated calcium hydroxide solution for 28 days. Next, a tensile jig was attached to the protective coating film using an adhesive and left standing for 24 hours. Then, cuts were made on the four sides of a 40×40 mm square around the jig, and the jig was pulled in the vertical direction to obtain the maximum tensile load.

[0087] The concrete protection formed from the concrete protection composition was measured in accordance with the pull-out test method 424 - 2011 of the NEXCO test method, Part 4, Structural Relationship Test Method, for anti-peeling. First, with the test specimen, which is a concrete body with a protective coating formed thereon, supported at both ends, a load was applied to the test specimen through a cylindrical pressure plate inserted into a through-hole provided on the back surface of the test specimen using a loading device. Next, the above loading was repeated while marking the peeling range for each displacement amount of the pull-out displacement. Then, the loading load (pull-out strength) at a pull-out displacement of 10 mm or more was measured.

[0088] [Examination of Resin] A protective coating was formed on the surface of a concrete body using an aqueous emulsion of resin, and the protective coating was evaluated. The types of resins used and the measurement results are shown in the following table. Note that from the viewpoints of water resistance, type of resin, and main skeleton, Examples 1 and 2 are considered to have an ○ evaluation for weather resistance.

[0089]

Table 1

[0090] [Examination of Thickener] Using the polycarbonate-based urethane resin of Example 2 above, a concrete protection composition was prepared. A concrete protection composition containing the components shown in Table 2 (the content of each component is shown in parts by mass) was prepared, a protective coating was formed on a concrete body, and the appearance of the protective coating was observed. The results are shown in Table 2.

[0091]

Table 2

[0092] [Examination of Sealer] When forming a protective coating film using the concrete protection composition prepared in the above Experimental Example 1-1, a sealer layer was formed on the concrete body and then the protective coating film was formed. Sealant layers were formed on the concrete body using various sealants, and after forming the protective coating film using the concrete protection composition, the adhesion of the protective coating film was measured. The results are shown in Table 3.

[0093]

Table 3

[0094] [Evaluation] From the above experiments, a protective coating film was formed on the following concrete bodies using a two-component epoxy-based aqueous sealer and a concrete protection composition having the following composition. The concrete protection composition was applied in two portions, for a total of 1.2 kg / m 2 . After applying the first portion of the concrete protection composition, a vinylon mesh was placed, and the second portion of the concrete protection composition was further applied thereon.

[0095]

Table 4

[0096] When the formed coating film was visually confirmed, it was found to be transparent and it was confirmed that the state of the surface of the concrete body could be visually recognized. Also, when evaluating the adhesion of the protective coating film, the adhesion after the alkali resistance test, and the concrete protection performance, the adhesion strength was 3.9 N / mm 2 , the adhesion strength after the alkali resistance test was 3.1 N / mm 2 , and the maximum load at a displacement of 10 mm or more was 2.2 kN.

Explanation of Signs

[0097] 110…Concrete body, 120…Protective coating film.

Claims

1. Comprising an aqueous emulsion of a polycarbonate-based urethane resin, wherein the polycarbonate-based urethane resin has a glass transition temperature of -40°C or higher and -15°C or lower, a breaking strength of 35 MPa or higher and 100 MPa or lower, and an elongation at break of 350% or higher and 1000% or lower, A composition for concrete protection.

2. The composition according to claim 1, having thixotropic properties.

3. The composition according to claim 1, wherein the thixotropy index is 2.0 or higher.

4. The composition according to claim 1, for application to concrete via an epoxy-based aqueous sealer.

5. The composition according to claim 1, further comprising a first thickener which is a (meth)acrylic polymer.

6. The composition according to claim 5, further comprising a second thickener which is a nonionic polymer.

7. The composition according to claim 1, for forming a transparent coating film.

8. A coating film forming kit for concrete protection, comprising the composition according to any one of claims 1 to 7 and an epoxy-based aqueous sealer.

9. The adhesion strength of the surface coating material measured in accordance with the Concrete Standard Specification JSCE-K 531-2013 of the coating film formed from the aqueous sealer and the composition is 3.0 N / mm 2 or more. The kit according to claim 8.

10. The coating film formed from the aqueous sealer and the composition for concrete protection has a maximum load at a displacement of 10 mm or more measured in accordance with the pull-out test for peel prevention in Test Method 424 - 2011 of Part 4 of the NEXCO Test Method, Structural Relationship Test Method, of 1.5 kN or more. The kit according to claim 8.

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