JP2020007181A - Concrete surface protective material - Google Patents

Abstract

To provide a concrete surface protective material which has good plastering properties and has little swelling even when exposed to alkaline conditions.SOLUTION: A concrete surface protective material of this invention comprises an adhesive resin layer which includes a mesh-like sheet therein, the adhesive resin layer contains glass beads of 0.5-13 mass% based on 100 mass% of the adhesive resin layer, and a mesh opening ratio of the mesh-like sheet is 43-73%.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a concrete surface protection material.

  The concrete that composes the reinforced concrete shows strong alkalinity, and by having the strong alkalinity property, the internal reinforcing steel is protected.

  On the other hand, the concrete surface protective material used for maintaining the durability of the concrete structure needs to have sufficient resistance to the strong alkalinity of the concrete.

  Regarding the alkali resistance of the concrete surface protective material, for example, in the standard for maintenance and management of reinforced concrete on the Tokaido Shinkansen, a concrete protective material is painted on a mortar plate, immersed in a saturated calcium hydroxide aqueous solution for half a day for 30 days, and then cracked and swelled in the concrete protective material. It is evaluated by a method of confirming that there is no peeling, softening or elution.

  Among the above-mentioned evaluation items, in particular, swelling is pointed out as a problem in discussing the performance of the concrete surface protective material. When the concrete surface protective material swells, it causes poor appearance and / or peeling of the surface protective material.

  On the other hand, one of the properties required for such a concrete surface protective material is an excellent plastering property of an adhesive composition for forming an adhesive resin layer. Generally, it is difficult to suppress blistering under alkaline conditions while maintaining excellent plastering properties, and it is considered difficult to obtain a concrete surface protective material that has both properties at a high level. Have been.

  In view of the above-mentioned circumstances, an object of the present invention is to provide a concrete surface protection material which has good plastering properties and has little swelling even when exposed to alkaline conditions.

  The present inventors have conducted intensive studies to achieve the above object, and as a result, by including glass beads in the adhesive resin layer of the concrete surface protective material, and by interposing a predetermined mesh sheet in the adhesive resin layer. It has been found that a concrete protective material with less swelling can be obtained even under alkaline conditions. The present inventors have further studied based on such findings, and have completed the present invention.

That is, the present invention provides the following concrete surface protection materials.
Item 1.
Equipped with a mesh sheet in the adhesive resin layer,
The adhesive resin layer contains 0.5 to 13% by mass of glass beads with respect to 100% by mass of the adhesive resin layer,
The mesh sheet has an opening ratio of 43 to 73% in the mesh sheet.
Concrete surface protection material.
Item 2.
Item 2. The concrete surface protective material according to item 1, wherein a protective sheet is provided on a surface of the adhesive resin layer opposite to a surface in contact with concrete.
Item 3. The protective material according to Item 1 or 2, wherein the 10% modulus of the adhesive resin layer is 0.7 or less.
Item 4.
Item 4. The protective material according to any one of Items 1 to 3, wherein the adhesive used for the adhesive resin layer has a viscosity of 10,000 to 1,000,000 mPa · s.
Item 5.
Item 5. The protective material according to any one of Items 1 to 4, wherein the glass beads have an average particle size of 0.05 to 1.8 mm.

  The concrete surface protective material of the present invention has good plastering properties, but has little swelling even when exposed to alkaline conditions.

FIG. 3 is an explanatory view of a concrete surface protection material of the present invention.

  The concrete surface protective material of the present invention comprises a mesh sheet in an adhesive resin layer, wherein the adhesive resin layer contains 0.5 to 13% by mass of glass beads in 100% by mass of the adhesive resin layer, The mesh sheet has a mesh opening ratio of 43 to 73%.

  Hereinafter, embodiments of the concrete surface protection material of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, a concrete surface protection material 100 of the present invention functions as a protection material for a concrete structure 200 having, for example, concrete 210 and a reinforcing bar 220. Is provided.

  The concrete surface protection material 100 includes a mesh sheet 140 in the adhesive resin layer 130. The mesh sheet 140 may be configured such that the mesh sheet 140 is provided on the surface of the concrete structure 200 and the adhesive resin layer 130 is laminated thereon. After providing the layer 130, a mode in which the mesh sheet 140 is provided may be adopted. However, in order to effectively exert the strength of the concrete surface protection material, as shown in FIG. 1, the first adhesive resin layer 110, the mesh sheet 140, and the second adhesive resin layer 120 are arranged in this order. It is preferable that they are laminated. It is also preferable to provide the protective sheet 300 on the surface of the adhesive resin layer 130 opposite to the surface that contacts the concrete 210. For example, the protective sheet 300 preferably includes the carbon film 320 and the resin layer 310. More specifically, as shown in FIG. 1, a concrete surface protection material having a carbon film 320, a resin layer 310, and an adhesive resin layer 130 in this order, and including a mesh sheet 140 in the adhesive resin layer 130. It is also preferred.

  The thickness of the concrete surface protective material (excluding the thickness of the protective sheet) is preferably at least 1.0 mm, more preferably at least 1.2 mm. When the thickness of the concrete surface protective material is 1.0 mm or more, good adhesion to concrete and good applicability (plastering property) can be obtained. On the other hand, the thickness of the concrete protective material is preferably 5 mm or less, more preferably 3.8 mm or less. When the thickness of the concrete protective material is 5 mm or less, good adhesiveness and good applicability (plastering property) can be obtained.

  In the case where the first adhesive resin layer and the second adhesive resin layer are provided as the adhesive resin layers, the respective adhesives are not limited as long as the entire thickness of the concrete surface protective material is preferably set within the above numerical range. The thickness of the resin layer may be set to, for example, substantially the same thickness, or may be set to different thicknesses. However, since the thickness of the plaster coating is controlled by the weight of the adhesive resin layer, the resin of each layer should be the same in terms of work management. Preferably, the layers are substantially the same.

  As the adhesive resin composition for forming the adhesive resin layer, known adhesives that can be bonded to concrete can be widely used, and there is no particular limitation. Specifically, an epoxy-based adhesive, a urethane-based adhesive, a silicone-based adhesive, and a rubber-based adhesive can be exemplified, and more preferably, a modified silicone resin, an epoxy resin, and the respective resins are cured. And an adhesive resin composition containing a curing agent for causing the adhesive to cure. Further, it is preferable to use a moisture-curable adhesive because it is assumed to be used in a high humidity environment and is cured even at a certain low temperature.

  The adhesive resin composition may be a so-called one-component resin composition or a two-component mixture of a so-called two-component resin composition. In the case of a one-pack type resin composition, the work is easy and the work efficiency is good, and furthermore, poor curing hardly occurs in that the uniformity of the adhesive resin composition to be cured is good, Therefore, good adhesiveness can be easily obtained. In the case of a two-pack type resin composition, the adhesiveness is good irrespective of the degree of irregularities and / or cracks on the surface of the concrete structure 200, and the weather resistance is also good.

  When the adhesive resin composition is a modified silicone resin, an epoxy resin, and an adhesive resin composition containing a curing agent for curing each resin, as an example of a one-pack type, the adhesive resin composition And a mixture containing a modified silicone resin, an epoxy resin, a silanol condensation catalyst, and an epoxy curing agent. Further, examples of the two-pack type agents I and II include the following. Part I includes a modified silicone resin and Part II includes an epoxy resin. In this case, the first agent further includes an epoxy curing agent, and the second agent further includes a silanol condensation catalyst.

  The modified silicone resin is not particularly limited, but is preferably a moisture-curable modified silicone resin, in which case it has a hydrolyzable silicon group. The modified silicone resin having a hydrolyzable silicon group has, as a main chain (a portion excluding the hydrolyzable silicon group), a polymer selected from the group consisting of polyether-based polymers, polyolefin-based polymers, and acrylic polymers. Therefore, the main chain may be a polymer of a monomer selected from the group consisting of an alkylene oxide component, an olefin component and an acrylic component, and the polymer may be a homopolymer or a copolymer. When it is a copolymer, the copolymer component may be selected from the group consisting of an alkylene oxide component, an olefin component, an acrylic component, and another vinyl component.

  Examples of the alkylene oxide component include ethylene oxide, propylene oxide, and butylene oxide. The main chain is preferably a polypropylene oxide mainly composed of propylene oxide units, from the viewpoints of elongation after curing and viscous handling. Isobutylene is mentioned as an olefin component.

  As the acrylic component, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) A) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, isomyristyl (meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, 2- Butoxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, hexanediol di ) Acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) ) Acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, 2-hydroxyethyl ( (Meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) Acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 3-hydroxy-3-methylbutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, 2-[(meth) acryloyloxy] ethyl 2-hydroxyethylphthalic acid, 2-[(meth) acryloyloxy] ethyl 2- Hydroxypropyl phthalic acid; When the acrylic polymer is a copolymer of another vinyl monomer component, a hydrolyzable silicon group can be introduced by copolymerizing a vinyl monomer component having a hydrolyzable silicon group.

  It is preferable that the main chain contains an acrylic unit in that the weather resistance becomes good. Further, from the viewpoint of weather resistance, the content of the acrylic unit in the main chain is preferably 5% by mass or more and 20% by mass or less.

  The hydrolyzable silicon group is not particularly limited, and examples thereof include a halogenated silyl group, an alkenyloxysilyl group, an acyloxysilyl group, an aminosilyl group, an aminooxysilyl group, an oximusilyl group, an amidosilyl group, and an alkoxysilyl group. Here, the number of hydrolyzable groups bonded to silicon atoms in the hydrolyzable silicon group is preferably from 1 to 3. Further, the number of hydrolyzable groups bonded to one silicon atom may be one or more. Further, a hydrolyzable group and a non-hydrolyzable group may be bonded to one silicon atom. As the hydrolyzable silicon group, an alkoxysilyl group such as a monoalkoxysilyl group, a dialkoxysilyl group, and a trialkoxysilyl group is preferable in terms of excellent stability and easy handling. The modified silicone resins may be used alone or in combination of two or more.

  The number average molecular weight of the modified silicone resin having a hydrolyzable silicon group is, for example, 1,000 to 500,000, 1,000 to 100,000, 10,000 to 30,000, 4,000 to 500. 4,000 or less, or 4,000 or more and 30,000 or less. When the number average molecular weight of the modified silicone resin is 1,000 or more, the curing time of the adhesive resin composition can be shortened, and the adhesive strength after curing becomes good. Further, when the number average molecular weight of the modified silicone resin is 500,000 or less, the viscosity of the adhesive resin composition becomes appropriate, and the workability when providing the concrete surface protective material on the concrete surface is improved.

  The silanol condensation catalyst is used to cure the modified silicone resin composition in a short time. Examples of the silanol condensation catalyst include poly (dialkylstannoxane) disilicate compounds, tin catalysts such as monoalkyltin esters and dialkyltin esters, and organic titanates.

  Examples of the monoalkyltin ester include butyltin tris (2-ethylhexanoate), and examples of the dialkyltin ester include dibutyltin acetate, dibutyltin dilaurate, dibutyltin dioctoate, dibutyltindiolate, and dibutyltin. Examples include dimethoxide, dibutyltin diphenoxide, dibutyltin diacetylacetonate, dibutyltin acetoacetate, and stannous octoate. Examples of the organic titanates include titanium alkoxides such as tetrabutyl titanate, tetraisopropyl titanate, tetramethyl titanate, tetra (2-ethylhexyl titanate) triethanolamine titanate, titanium tetraacetylacetonate, titanium ethyl acetoacetate, and octylene glycol. Titanium chelates such as rate. The silanol condensation catalyst may be used alone or in combination of two or more.

  The content of the silanol condensation catalyst in the adhesive resin composition is preferably from 0.1 to 10 parts by mass, preferably from 1 to 5 parts by mass, based on 100 parts by mass of the modified silicone resin. More preferably, there is. When the amount of the silanol condensation catalyst is 0.1 part by mass or more based on 100 parts by mass of the modified silicone resin, the curing time of the adhesive resin can be shortened. On the other hand, when the amount of the silanol condensation catalyst is 10 parts by mass or less based on 100 parts by mass of the modified silicone resin, physical properties such as adhesive strength of the adhesive resin can be suitably maintained.

  The epoxy resin is not particularly limited, and may be any resin having an epoxy group. Specific examples include those in which a glycidyl group is bonded to a compound selected from the group consisting of unsaturated aliphatic compounds, alicyclic compounds, aromatic compounds, and heterocyclic compounds. From the viewpoint of the neutralization suppressing effect, it is preferable that the compound contains an aromatic compound.

  Examples of the epoxy resin include bisphenol type epoxy resins such as bisphenol A type, bisphenol F type, bisphenol S type and hydrogenated products thereof; glycidyl ether type epoxy resins such as polypropylene glycol diglycidyl ether type epoxy resin; Ester type epoxy resins such as glycidyl ester type epoxy resin; Novolak type epoxy resins such as phenol novolak type and cresol novolak type; bisphenol A novolak type epoxy resins and hydrogenated products thereof; Trisphenol type such as triphenol methane type epoxy resin Polyfunctional epoxy resin; triglycidyl isocyanurate type, tetraglycidyl diaminodiphenylmethane type, tetraglycidyl meta-xylene diamine type, hidan Nitrogen-containing cyclic polyfunctional epoxy resin such as in type; condensed ring epoxy resin such as naphthalene type; biphenyl type epoxy resin; dicyclopentadiene type epoxy resin; ether ester type epoxy resin; 3,4-epoxycyclohexylmethyl-3 Epoxy resins having an alicyclic structure such as', 4'-epoxycyclohexanecarboxylate; urethane-type epoxy resins; rubber-modified epoxy resins having a rubber skeleton such as polybutadiene and acrylonitrile-butadiene rubber (NBR) can be used. One epoxy resin may be used alone, or two or more epoxy resins may be used in combination.

  The content of the epoxy resin in the adhesive composition is preferably 1 part by mass or more and 100 parts by mass or less, more preferably 2 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the modified silicone resin. . When the content of the epoxy resin is 1 part by mass or more based on 100 parts by mass of the modified silicone resin, good toughness can be obtained in the cured adhesive resin layer. When the content of the epoxy resin is 100 parts by mass or less, good elasticity can be obtained in the cured adhesive resin layer.

Examples of the epoxy curing agent include amine compounds. As the amine compound, aliphatic tertiary amines such as N, N-dimethylpropylamine, N, N, N ′, N′-tetramethylhexamethylenediamine, N-methylpiperidine, N, N′-dimethylpiperazine, etc. Alicyclic tertiary amines, tertiary aromatic amines such as benzyldimethylamine, dimethylaminomethylphenol, 2,4,6-tris (dimethylaminomethyl) phenol, ethylenediamine, diethylenetriamine, triethylenetetramine, pentaethylene Aliphatic diamines such as hexamine, trimethylenediamine, hexamethylenediamine, tetramethylenediamine, alicyclic diamines such as 1,3-bis (aminomethyl) cyclohexane, isophoronediamine, norbornenediamine, diaminodiphenylmethane, Metaphenylene And aromatic diamines such as diamine.
In addition to the above, examples of epoxy curing agents include polyamide resins; imidazoles such as 2-ethyl-4-methylimidazole; and compounds such as carboxylic anhydrides such as phthalic anhydride.

Further, the epoxy curing agent may be a latent curing agent such as ketimine which has an active amine blocked and is activated under predetermined conditions such as moisture. For example, ketimine is stably present in the absence of moisture, but generally becomes a primary amine due to the presence of moisture and reacts with an epoxy resin. Specifically, 2,5,8-triaza-1,8-nonadiene, 2,10-dimethyl-3,6,9-triaza-2,9-undecadiene, 2,10-diphenyl-3,6,9 -Triaza-2,9- undecadiene, 3,11-dimethyl-4,7,10-triaza-3,10-tridecadiene, 3,11-diethyl-4,7,10-triaza-3,10-tridecadiene, 2 , 4,12,14-Tetramethyl-5,8,11-triaza-4,11-pentadecadiene, 2,4,20,22-Tetramethyl-5,12,19-triaza-4,19-tri Eicosadiene, 2,4,15,17-tetramethyl-5,8,11,14-tetraaza-4,14-octadecadiene and the like.
The epoxy curing agents may be used alone or in combination of two or more.

  The content of the epoxy curing agent in the adhesive resin composition is preferably 20 parts by mass or more and 60 parts by mass or less, more preferably 30 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the epoxy resin. preferable. Alternatively, when a latent curing agent is used as the epoxy curing agent, the total number of moles of epoxy groups of the epoxy resin to the total number of moles of active amino groups generated by activation (total number of moles of epoxy group / total number of active amino groups) (Molar number) is preferably 0.8 or more and 1.2 or less, and more preferably 0.9 or more and 1.1 or less. It is preferable from the viewpoint of the elastic modulus of the cured film that it is not less than the above lower limit, and it is preferable from the viewpoint of storage stability that it is not more than the above upper limit.

  The adhesive resin composition may further contain other additives as necessary. Other additives include a dehydrating agent, an epoxy silane coupling agent, an antioxidant, a filler, a plasticizer, an anti-sagging agent, an ultraviolet absorber, a pigment, a solvent, and a fragrance.

  As the above-mentioned adhesive resin composition, a non-heated or heated one further added with water may be used. When heated, the temperature may be, for example, 40 degrees or more and 80 degrees or less. It is preferable that the ratio is not less than the lower limit in that a sufficient adhesive force can be obtained in a short time. It is preferable that the amount is equal to or less than the above upper limit in order to prevent damage to the protective sheet.

  The viscosity of the adhesive resin composition is based on JIS K6833, and the initial viscosity at 23 ° C. and 50% RH is preferably 10,000 mPa · S or more and 1,000,000 mPa · S or less, and 50,000 mPa · S or more and 800000 mPa. -More preferably, it is S or less. The initial viscosity is a viscosity measured at a rotation speed of 10 rpm using a rotor 7 of a BS type viscometer. When the viscosity of the adhesive resin composition is 10,000 mPa · S or more, the adhesive resin composition has an appropriate viscosity, which is preferable in view of workability. In addition, when the viscosity of the adhesive resin composition is 1,000,000 mPa · S or less, the adhesiveness of the adhesive resin layer to the irregularities on the surface of the concrete structure 200 is improved, which is preferable in terms of adhesiveness. Furthermore, the adhesive resin composition easily enters the mesh sheet 140, and as a result, it is possible to eliminate poor appearance due to poor defoaming and decrease in adhesion due to unfilled adhesive resin composition.

  There is no particular limitation on the components constituting the glass beads contained in the adhesive resin layer. Specifically, one or more selected from the group consisting of soda lime, silicon dioxide, alumina, sodium oxide, calcium oxide, iron oxide, potassium oxide, and pearlite can be exemplified.

  The average particle size of the glass beads is preferably 0.05 mm or more, more preferably 0.075 mm or more. By employing such a configuration, good plastering properties can be obtained. On the other hand, the average particle diameter of the glass beads is preferably 1.8 mm or less, more preferably 0.5 mm or less. By employing such a configuration, good plastering properties can be obtained. In this specification, the average particle diameter of the glass beads is defined as a value obtained by an image analysis method.

  The shape of the glass beads is not particularly limited. Specifically, a spherical hollow shape and a solid shape (a solid shape, not a hollow state) can be exemplified.

  The content of the glass beads in the adhesive resin layer is 0.5% by mass or more, preferably 1.0% by mass or more based on 100% by mass of the adhesive resin layer. When the content of the glass beads is less than 0.5% by mass, the state becomes the same as the state without the glass beads. On the other hand, the content of the glass beads in the adhesive resin layer is 13% by mass or less, preferably 10% by mass or less in 100% by mass of the adhesive resin layer. If the content of the glass beads exceeds 13% by mass, the viscosity becomes too high, and good plastering properties are lost.

  When a moisture-curable adhesive is used as the adhesive resin composition, the content of the glass beads included in the adhesive resin composition and the adhesive resin layer after the adhesive resin composition is cured are included in the adhesive resin layer. It is almost equal to the content of glass beads.

  The 10% modulus of the cured adhesive resin layer is preferably 0.2 or more, and more preferably 0.3 or more. By adopting such a configuration, it is possible to obtain an effect that it is possible to follow a crack that is wide and moves. The 10% modulus of the cured adhesive resin layer is preferably 0.7 or less, more preferably 0.5 or less. By adopting such a configuration, even if stress is repeatedly applied to the concrete surface protection material after construction due to the elasticity of the cured product of the adhesive resin layer, it is possible to effectively suppress cracking of the concrete surface protection material. be able to. In the present specification, the 10% modulus refers to a stress at 10% elongation (10% modulus) in accordance with JIS K6251 "Vulcanized rubber and thermoplastic rubber-Determination of tensile properties".

  In the present invention, applying the adhesive resin composition is not limited to providing the adhesive resin composition layer by a coating method, but also includes providing the adhesive resin composition layer by a dipping method, a spray method, or the like. . Examples of the coating method include a method using a roll, a spatula, a trowel, and the like, ironing, brushing, and flow coating. When applying using a roll, a rubber or metal roll can be used, and further, it can be applied in the form of two rolls or three rolls.

  In the mesh sheet, the mesh sheet is installed horizontally, and the ratio of the mesh opening area to the entire area of the mesh sheet viewed from above (hereinafter referred to as mesh opening ratio) is 43 to 73%. More preferably, it is 50 to 70%. When the mesh opening ratio is less than 43%, the amount of the adhesive resin composition existing in the openings of the mesh decreases, and the adhesion strength decreases. On the other hand, when the mesh opening ratio exceeds 73%, the area of the adhesive resin composition is large, and the adhesive resin composition is easily affected by water in the alkali resistance test, so that swelling occurs.

  As the material of the mesh sheet, known fibers can be used, and there is no particular limitation. Specifically, at least one selected from the group consisting of vinylon fiber, polyester fiber, polypropylene fiber, polyethylene fiber, carbon fiber, aramid fiber, glass fiber, and basalt fiber can be used.

  Specific examples of the mesh sheet include a mesh, a woven fabric, a knitted fabric (net), and a nonwoven fabric, and one of these can be used alone or in combination of two or more. Among them, a mesh is preferable from the viewpoint of the ability to prevent peeling. In the present specification, a mesh is defined as a substrate having a structure in which a plurality of continuous fiber bundles are cross-laminated and the fiber bundles are preferably bonded at the intersection. Specifically, a biaxial mesh (lattice mesh), a triaxial mesh, a four-axis mesh, a five-axis mesh, and a multi-axial mesh (multi-dimensional mesh) of more than that can be mentioned, and a viewpoint that the peeling prevention ability can be more preferable. From the viewpoint, a multi-axis mesh having three or more axes is preferable. The triaxial mesh is preferably a multiaxial mesh that is laminated in three directions of a warp direction, a diagonal direction, and a reverse diagonal direction, specifically, so that the intersection angle of the fiber bundle is 60 degrees. More specifically, a braid (registered trademark) is given.

The mesh pitch of the mesh sheet may be appropriately set so that the mesh opening ratio falls within the range of 43 to 73%, and is not particularly limited. Specifically, it is preferably 3 to 15 mm, more preferably 5 to 12 mm. Similarly with respect to the weight per unit area of the mesh sheet may be appropriately set so that the mesh aperture ratio within the range of 43 to 73%, preferably from 30 to 100 g / ^{m 2,} is 40~90g / ^{m 2} Is more preferable.

  The thickness of the mesh sheet is not particularly limited, but may be, for example, 0.01 to 1 mm. By acting such a configuration, if it is equal to or more than the lower limit value, it is excellent in peeling prevention performance, and if it is equal to or less than the upper limit value, the effect is obtained that the integrity of the resin composition disposed on both sides of the mesh is improved. be able to.

  It is also preferable to further provide a protective sheet on the concrete surface protective material of the present invention. The protective sheet is not particularly limited as long as it can be adhered with the adhesive resin composition and can cover the surface of the adhesive resin composition. Specifically, an embodiment including a resin layer and a carbon film can be given. More specifically, it is preferable to provide a concrete surface protection material having a carbon film, a resin layer, and an adhesive resin layer in this order, and including a mesh sheet in the adhesive resin layer.

  The material of the resin layer may be any resin, for example, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyamide, acrylic resin, phenol resin, melamine resin, epoxy resin, urea resin, vinyl chloride resin, polyethylene, and polypropylene. One or more selected from the group can be used.

  The thickness of the resin layer is preferably 1 μm or more and 1000 μm or less, more preferably 10 μm or more and 500 μm or less. When the thickness of the resin layer is 1 μm or more, neutralization of concrete can be suppressed. In addition, when the thickness of the resin layer is 1000 μm or less, it is possible to obtain good adhesion workability of the protective sheet to the concrete structure.

The resin layer, the coefficient of linear expansion which conforms to JIS K7197 is preferably less ¹⁰ × 10 ^-5 / K, not more than 5 × ^{10 -5} / K, more preferred. When the thickness is equal to or less than the upper limit, cracking of the resin layer itself is prevented, and cracking of the carbon film following the crack is easily suppressed.

  As the carbon film, various carbon films are used, and a diamond-like carbon (DLC) film is preferable from the viewpoint of a neutralization suppressing effect and further from the viewpoint of suppressing transmission of oxygen and / or water vapor. The DLC film is an amorphous film containing both a diamond structure (sp3 bond) and a graphite structure (sp2 bond). Further, hydrogen may or may not be contained. The mixing ratio of the diamond structure and the graphite structure and the hydrogen content are not particularly limited. More specifically, ta-C, a-C, ta-C: H, and aC: H are mentioned.

  In order to form an adhesive resin layer capable of effectively suppressing cracks in the carbon film, for example, it is also preferable to use a carbon film having a hardness of 1 GPa or more measured by a nanoindentation method. Note that the nanoindentation method is a method in which an indenter (for example, a nano-order needle) is pressed into the surface of a material, and the hardness, Young's modulus, and the like of a minute region are measured from the load and the amount of displacement. As an example, it can be measured as follows. Using a Triboscope manufactured by Hysitron, a triangular pyramid-shaped diamond indenter called a Berkovich indenter is applied to the sample surface at right angles, and a load is gradually applied from the carbon film surface to an indentation of 10% of the thickness of the carbon film. Gradually return the load to zero. The value P / A obtained by dividing the maximum load P at this time by the projected area A of the indenter contact portion is calculated as the hardness.

  The thickness of the carbon film is preferably 0.01 μm or more and 1 μm or less, more preferably 0.02 μm or more and 0.5 μm or less. By setting the thickness of the carbon film to 0.01 μm or more, neutralization of concrete can be suppressed. By setting the thickness of the carbon film to 1 μm or less, it is possible to suppress the occurrence of cracks in the carbon film of the protective sheet.

  The protective sheet can be manufactured by using a resin layer as a base material and forming a carbon film by various vapor deposition methods. For example, specific examples of the vapor phase film forming method include a plasma CVD method and a sputtering method. Further, examples of the plasma CVD method include an atmospheric pressure plasma CVD method and a plasma CVD method under a high vacuum.

  Although the embodiments of the present invention have been described above, the present invention is not limited to such examples at all, and it is needless to say that the present invention can be implemented in various forms without departing from the gist of the present invention.

  Hereinafter, embodiments of the present invention will be described more specifically with reference to Examples, but the present invention is not limited thereto.

(Swelling evaluation test <Alkali resistance test>)
For each Example and Comparative Example, a first adhesive resin layer was provided by applying the adhesive shown in Table 1 below to a mortar test piece (70 × 70 × t20 mm). Was placed thereon, and a second adhesive resin layer was further formed thereon. Further, a plastic sheet on which an amorphous carbon film was deposited was attached thereon. The thickness of the formed concrete surface protective material was 1.7 mm. The mortar coated with the obtained concrete surface protective material was immersed in a saturated solution of calcium hydroxide for 30 and a half days. After immersion, it was confirmed that there was no crack, swelling, peeling or elution.

(Plaza evaluation test)
For each of the examples and comparative examples, the adhesives shown in Table 1 below were spread on a JIS concrete flat plate (60 × 600 × 400 mm) using a spatula and a trowel to elongate, sharpen, string and remove. The ease of foaming was evaluated. As an evaluation method, elongation, sharpness, and stringing were collectively evaluated as plastering, and a score was given to an expert who had experience in civil engineering work with a maximum score of 3 points. Defoaming was similarly scored as defoaming property, and the condition where the total score of plastering property and defoaming property was 6 was regarded as good plastering property.

(Adhesion evaluation test)
The adhesion strength test of concrete protection material was performed according to JSCE K531-1999 "Test method of adhesion strength of surface protection material". After the concrete surface protection material was applied to the mortar test piece, it was cured for 28 days and an adhesion test was performed.

  As shown in Table 1, the concrete surface protective materials of the examples had good plastering properties and showed little swelling even when exposed to alkaline conditions. On the other hand, the concrete surface protective material of each comparative example did not have sufficient performance in any of the above properties.

REFERENCE SIGNS LIST 100 Concrete surface protective material 110 First adhesive resin layer 120 Second adhesive resin layer 130 Adhesive resin layer 140 Mesh sheet 200 Concrete structure 210 Concrete 220 Reinforcing bar 300 Protective sheet 310 Resin layer 320 Carbon film

Claims (5)

Equipped with a mesh sheet in the adhesive resin layer,
The adhesive resin layer contains 0.5 to 13% by mass of glass beads with respect to 100% by mass of the adhesive resin layer,
The mesh sheet has an opening ratio of 43 to 73% in the mesh sheet.
Concrete surface protection material.   The concrete surface protection material according to claim 1, wherein a protection sheet is provided on a surface of the adhesive resin layer opposite to a surface in contact with concrete.   The protective material according to claim 1, wherein a 10% modulus of the adhesive resin layer is 0.7 or less.   The protective material according to any one of claims 1 to 3, wherein the adhesive used for the adhesive resin layer has a viscosity of 10,000 to 1,000,000 mPa · s.   The protective material according to any one of claims 1 to 4, wherein the average particle diameter of the glass beads is 0.05 to 1.8 mm.

Images