JP2021031927A - Water retentivity imparting agent for porous pavement body and water retentive pavement manufacturing method - Google Patents

Abstract

To provide a water retentivity imparting agent for a porous pavement body that can easily realize a water retentive pavement having good water retentive performance and can remarkably suppress an increase in the pavement surface temperature.SOLUTION: A water retentivity imparting agent for a porous pavement body includes: powder having a pavement surface temperature reduction capability; and at least one water retentivity imparting component selected from the following (A), (B), and (C). (A) A water retentivity imparting component containing a polymer, having a cross-linkable functional portion cross-linked with a cross-linking agent, and a cross-linking agent, and having a water retaining gel forming ability at room temperature; (B) a water retentivity imparting component containing a water-absorbing resin and a polysaccharide having a gel-forming ability in the presence of an alkali metal salt or an alkaline earth metal salt; and (C) a water retentivity imparting component containing a water-absorbing resin and a resin emulsion.SELECTED DRAWING: None

Description

The present invention relates to a water-retaining agent for a porous pavement and a method for producing a water-retaining pavement.

Studies on the practical application of water-retaining pavement are underway. The water-retaining pavement has a function of retaining moisture due to rain or the like and suppressing an increase in road surface temperature by removing heat of vaporization when the retained moisture evaporates. This function is expected to alleviate the heat island phenomenon. The water-retaining pavement is typically constructed by filling the voids of the porous pavement on the road surface with a water-retaining material. As an example of the method of constructing the water-retaining pavement, there is a method of fixing the water-retaining material with cement, and more specifically, a method of spraying the water-retaining material on uncured porous concrete. Another example of forming a water-retaining pavement is a method of filling the voids of a porous pavement with a water-retaining material.

Japanese Unexamined Patent Publication No. 2006-274743

In water-retaining pavement, there is a basic and continuous demand for suppressing an increase in road surface temperature (pavement surface temperature), but the above-mentioned technology cannot sufficiently suppress an increase in road surface temperature.
The present invention has been made in view of the above-mentioned conventional problems, and its main purpose is to easily realize a water-retaining pavement having good water-retaining performance and to remarkably suppress an increase in the pavement surface temperature. It is an object of the present invention to provide a water-retaining agent for a porous pavement.

The water-retaining agent for a porous pavement of the present invention includes a powder having a pavement surface temperature reducing ability and at least one water-retaining component selected from the following (A), (B) and (C). ,including:
(A) A water-retaining component containing a polymer having a crosslinkable functional portion crosslinked with a cross-linking agent and a cross-linking agent and having a water-retaining gel-forming ability at room temperature;
(B) A water-retaining component containing a water-absorbent resin and a polysaccharide having a gel-forming ability in the presence of an alkali metal salt or an alkaline earth metal salt;
(C) A water-retaining component containing a water-absorbent resin and a resin emulsion.
In one embodiment, the powder capable of reducing the pavement surface temperature has at least one property selected from the following (a), (b) and (c):
(A) Thermal conductivity is greater than 0.74 (W / m · K);
(B) Whiteness is 65% or more;
(C) The water content is 10% or more.
In one embodiment, the powder having the ability to reduce the pavement surface temperature is carbon black, magnesium oxide, zinc oxide, aluminum oxide, calcium carbonate, magnesium hydroxide, magnesium carbonate, titanium oxide, aluminum hydroxide, barium sulfate. , Tarku, clay, kaolin, wollastonite, calcium silicate, permiculite, attapargite, sepionite, bentonite and montmorillonite, at least one selected from the group.
In one embodiment, the powder having the ability to reduce the surface temperature of the pavement is used for the porous pavement at a ratio of 1.0 part by mass to 2000 parts by mass with respect to 100 parts by mass of the solid content of the water-retaining component. It is contained in the water retention imparting agent.
In one embodiment, the porous pavement water retention agent further comprises a thickener.
According to another aspect of the present invention, there is provided a method for producing a water-retaining pavement. The method for producing a water-retaining pavement of the present invention includes applying, spraying, injecting or filling the above-mentioned water-retaining agent for a porous pavement onto a porous pavement.

According to the embodiment of the present invention, good water retention performance can be achieved by using a powder having at least one of thermal conductivity, whiteness and water content specified in a predetermined range in combination with a specific water retention-imparting component. It is possible to easily realize a water-retaining pavement having a water-retaining property, and to realize a water-retaining agent for a porous pavement body, which can remarkably suppress an increase in the pavement surface temperature.

Hereinafter, specific embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

I. Outline of Water-Retaining Agent for Porous Pavement The water-retaining agent for porous pavement according to the embodiment of the present invention includes a powder having a pavement surface temperature reducing ability, a water-retaining component, and a practically aqueous medium (a water-retaining medium (practically). Typically, it includes water). The water retention-imparting component is selected from the following (A), (B) and (C): (A) A polymer having a crosslinkable functional moiety crosslinked with a crosslinker and a crosslinker, and retain water at room temperature. A water-retaining component having a gel-forming ability; (B) a water-retaining component containing a water-absorbent resin and a polysaccharide having a gel-forming ability in the presence of an alkali metal salt or an alkaline earth metal salt; (C. ) A water-retaining component containing a water-absorbent resin and a resin emulsion. These water-retaining components may be used alone or in combination of two or more.

As used herein, the term "water retention" refers to a function capable of repeatedly absorbing, retaining and releasing water. That is, the water-retaining agent introduced into the porous pavement can absorb and retain water due to rain or the like, release the retained water by evaporation, and absorb, retain, and retain such moisture. The release can be repeated. According to the embodiment of the present invention, a water-retaining pavement having such good water-retaining performance can be realized by using the water-retaining components as described in (A) to (C) above.

A powder having a pavement surface temperature reducing ability (hereinafter, also referred to as a surface temperature reducing powder) typically has at least one of the following properties (a), (b) and (c): ( a) Thermal conductivity is greater than 0.74 (W / m · K); (b) Whiteness is 65% or greater; (c) Moisture content is 10% or greater. By using such a surface temperature reducing powder, it is possible to remarkably suppress an increase in the pavement surface temperature. The surface temperature reducing powder may be used alone or in combination of two or more. For example, the surface temperature reducing powder having any one of the characteristics (a) to (c) may be used alone, or the surface temperature reducing powder having two or more of the characteristics (a) to (c). May be used alone, and the surface temperature-reducing powder having any one of the properties (a) to (c) (for example, thermal conductivity) and another one of the properties (a) to (c) (for example). For example, it may be used in combination with a surface temperature reducing powder having whiteness), and the surface temperature having any one of the characteristics (a) to (c) and having different specific values of the characteristics. Reduced powders may be used in combination. The number of combinations of the surface temperature reducing powders and the characteristics to be combined can be appropriately set according to the purpose. By using such a surface temperature-reducing powder, for example, a water-retaining agent having the same structure as the pavement surface temperature under conditions similar to the sunshine part in summer, except that the surface temperature-reducing powder is not used. It can be preferably 3 ° C. or higher, more preferably 5 ° C. or higher, still more preferably 7 ° C. or higher, and particularly preferably 10 ° C. or higher. Further, the temperature of the pavement surface under the same conditions as described above is preferably 10 ° C. or higher, more preferably 13 ° C. or higher, still more preferably 16 ° C. or higher, particularly preferably 16 ° C. or higher, as compared with the case where the water retention-imparting agent is not used. It can be lowered by 20 ° C. or higher.

In the water-retaining agent for porous pavement, the surface temperature-reducing powder may be contained in a ratio of 1.0 part by mass to 2000 parts by mass with respect to 100 parts by mass of the solid content of the water-retaining component. The content of the surface temperature reducing powder may change depending on the characteristics (a) to (c) that the surface temperature reducing powder may have. For example, the surface temperature-reducing powder having a predetermined thermal conductivity (characteristic (a)) is preferably 1.0 part by mass to 1000 parts by mass, more preferably 1.0 part by mass, based on 100 parts by mass of the solid content of the water-retaining component. It can be contained in a proportion of 1.2 parts by mass to 50 parts by mass. Further, for example, the surface temperature-reducing powder having a predetermined whiteness (characteristic (b)) is preferably 30 parts by mass to 2000 parts by mass, more preferably 50 parts by mass with respect to 100 parts by mass of the solid content of the water-retaining component. It can be contained in a proportion of 1600 parts by mass. Further, for example, the surface temperature-reducing powder having a predetermined thermal conductivity and whiteness (characteristics (a) and (b)) is given priority in the configuration of exhibiting whiteness, and the solid content of the water-retaining component is 100 parts by mass. On the other hand, it can be contained in a proportion of preferably 30 parts by mass to 2000 parts by mass, and more preferably 50 parts by mass to 1600 parts by mass.

The water-retaining agent for porous pavement is typically a so-called one-component type, and before being applied, sprayed, injected or filled in the porous pavement (introduction of the water-retaining agent for porous pavement). Pre-prepared (before work). Therefore, in the work of introducing the water-retaining agent for the porous pavement into the porous pavement, additional and complicated operations such as two-component mixing can be omitted. Further, the water-retaining agent for a porous pavement is excellent in handleability and workability because it can maintain a liquid state during the introduction work into the porous pavement. Needless to say, if necessary, each component may be mixed at the time of introduction work to prepare a water-retaining agent for a porous pavement. For example, a cross-linking agent in the water-retaining component (A) and an alkali metal salt or an alkaline earth metal salt capable of functioning as a catalyst for the gelation reaction in the water-retaining component (B) can be mixed during the introduction operation. Further, the water-retaining agent for a porous pavement may be stored at a low temperature, if necessary, in order to suppress a cross-linking or gelation reaction before introduction into the porous pavement.

The water-retaining agent for porous pavement may further contain a thickener, if necessary. By using a thickener, it is possible to prevent the surface temperature-reducing powder from settling, and therefore, it can be well dispersed in the water-retaining agent for porous pavement (substantially, an aqueous medium). it can. As a result, it is possible to remarkably suppress an increase in the pavement surface temperature in the water-retaining pavement. Representative examples of thickeners include hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, and ethyl methyl cellulose. The content (including zero) of the thickener in the water-retaining agent for porous pavement can be appropriately set according to the type and content of the surface temperature reducing powder.

The water-retaining agent for a porous pavement may contain fibers, if necessary. By using the fiber, the movement of water in the water-retaining agent for porous pavement can be promoted, and therefore, the water evaporation of the water-retaining agent for porous pavement is promoted, so that excellent surface temperature reduction performance is achieved. Can be obtained. Typical examples of fibers include rock wool, ceramic fibers (for example, refractory ceramic fibers, alumina fibers), alkaline earth silicate wool, cellulose fibers, polypropylene fibers, polyethylene fibers, acrylic fibers, polyamide fibers, acetate fibers, polyester fibers, etc. Examples include cellulose-based regenerated fibers (for example, rayon and cupra) and glass wool. The fiber content (including zero) in the water-retaining agent for porous pavement is appropriately set according to the type and content of the surface temperature reducing powder.

The water retention-imparting agent for porous pavement may further contain any suitable additive. Specific examples of additives include dispersants, antifoaming agents, rheology control agents, foaming agents, plasticizers, wetting agents, antiblocking agents, antiaging agents, preservatives, antistatic agents, UV absorbers, and UV stabilizers. , Leveling agents, plasticizers, dyes, pigments, antioxidants. The type, combination, amount, and the like of the additives contained in the water-retaining agent for a porous pavement can be appropriately set according to the purpose.

Hereinafter, the surface temperature reducing powder and the water retention-imparting component will be specifically described.

II. Surface Temperature Reduced Powder As described above, the surface temperature reduced powder typically has at least one of the following properties (a), (b) and (c): (a) thermal conductivity. Greater than 0.74 (W / m · K); (b) whiteness is 65% or greater; (c) water content is 10% or greater. The surface temperature-reducing powder having a thermal conductivity (characteristic (a)) of the above-mentioned predetermined value or more increases the thermal conductivity of the water-retaining agent (as a result, the water-retaining pavement) introduced into the porous pavement. As a result, the evaporation of water (typically caused by an aqueous medium) in the water-retaining agent (water-retaining pavement) is promoted, and the heat of vaporization is taken away at the time of the evaporation, so that the pavement of the water-retaining pavement is deprived. The rise in surface temperature can be suppressed. The surface temperature-reducing powder having a whiteness (characteristic (b)) equal to or higher than the above-mentioned predetermined value reduces the amount of heat absorbed by the water-retaining pavement by reflecting sunlight, and increases the pavement surface temperature of the water-retaining pavement. Can be suppressed. The surface temperature reducing powder having a water content (characteristic (c)) of the predetermined value or more increases the absolute amount of water in the water retention imparting agent (as a result, the water retention pavement) introduced into the porous pavement. As a result, the amount of water evaporated in the water-retaining pavement increases, which can suppress an increase in the pavement surface temperature of the water-retaining pavement. Further, since the surface temperature-reducing powder having a water content equal to or higher than the above-mentioned predetermined value has a high water-retaining ability, the water in the water-retaining pavement can be retained for a long period of time. Due to the moisture retained for such a long period of time, an increase in the pavement surface temperature of the water-retaining pavement can be suppressed for a long period of time.

The thermal conductivity is preferably 1.0 (W / m · K) or more, and more preferably 20 (W / m · K) or more. In one embodiment, the thermal conductivity is preferably 1.0 (W / m · K) to 2.0 (W / m · K). In another embodiment, the thermal conductivity is preferably 20 (W / m · K) to 60 (W / m · K), more preferably 20 (W / m · K) to 40 (W / W /). m ・ K). In yet another embodiment, the thermal conductivity is preferably 50 (W / m · K) to 60 (W / m · K). In yet another embodiment, the thermal conductivity is preferably 100 (W / m · K) to 300 (W / m · K).

The whiteness is preferably 65% or more, more preferably 75% or more, further preferably 80% or more, particularly preferably 85% or more, particularly preferably 90% or more, and most preferably. Is over 95%. The higher the whiteness, the more preferable, ideally 100%, and the upper limit of the whiteness can be, for example, 98%. Whiteness can typically be measured by a Hunter white meter.

The water content is preferably 12% to 25%, more preferably 12% to 20%. The water content is 12% to 13% in one embodiment and 14% or more in another embodiment. With such a water content, a desired amount of evaporation can be achieved in water-retaining pavement. Further, the surface temperature-reducing powder having such a water content can be excellent in water retention and moisture absorption / desorption. Therefore, such a surface temperature reducing powder can retain the water content in the water-retaining pavement for a long period of time, and can slowly evaporate the water content over a long period of time. As a result, good surface temperature reduction performance can be maintained for a long period of time in water-retaining pavement.

As the surface temperature reducing powder, any suitable powder can be adopted as long as it has at least one of the above characteristics (a) to (c). The surface temperature reducing powder is typically an inorganic powder. Specific examples include carbon black (thermal conductivity: 100 to 250), magnesium oxide (thermal conductivity: 50 to 60, whiteness: 90 or more), zinc oxide (thermal conductivity: 25 to 54, whiteness: 80). ), Aluminum oxide (thermal conductivity: 23 to 36, whiteness: 90 or more), calcium carbonate (thermal conductivity: 1-2, whiteness: 93 or more), magnesium hydroxide (whiteness 85 or more), carbon dioxide Magnesium (whiteness: 85 or more), titanium oxide (whiteness: 85 or more), aluminum hydroxide (whiteness: 95 to 96), barium sulfate (whiteness: 85 or more), talc (whiteness: 65 or more), Clay (whiteness: 68 or more), kaolin (whiteness: 80 or more), wollastonite (whiteness: 88 or more), attapargite (moisture content: 12-13), sepionite (moisture content: 14), bentonite (moisture content) Rate: 8 or more), montmorillonite (moisture content: 8 or more), calcium silicate, permiculite. As described above, the surface temperature reducing powder may be used alone or in combination of two or more. Preferred are carbon black, magnesium oxide, magnesium hydroxide, aluminum oxide (alumina), and combinations thereof. This is because it is excellent in versatility, availability, and ability to reduce surface temperature. The unit is omitted for the characteristic value in parentheses in the specific example.

The average particle size of the surface temperature reducing powder is preferably 10 nm to 150 μm, more preferably 30 nm to 75 μm. When the average particle size is in such a range, the amount of surface temperature reducing powder required for exhibiting the surface temperature reducing performance can be satisfactorily introduced into the water retention imparting agent for porous pavement, and the porous material is porous. It has an advantage that the water-retaining agent for a pavement can be satisfactorily introduced into a porous pavement.

The specific surface area (BET) of the surface temperature-reduced powder is preferably 1 (m ² / g) to 300 (m ² / g), more preferably 5 (m ² / g) to 200 (m ² / g). ). When the specific surface area is within such a range, heat conduction between the surface temperature-reducing powder and the aqueous medium and the water-retaining component is efficiently performed, and the water evaporation of the water-retaining agent can be promoted, which is very excellent. It has the advantage that the surface temperature reduction performance can be obtained.

The apparent specific gravity of the surface temperature reducing powder is preferably 0.01 (g / ml) to 2 (g / ml), more preferably 0.02 (g / ml) to 1 (g / ml). .. When the apparent specific gravity is in such a range, the surface temperature reducing powder can be uniformly dispersed in the water-retaining component and the aqueous medium, and as a result, the water-retaining property for the porous pavement is imparted from the porous pavement. Since heat conduction inside the agent and the water-retaining agent for porous pavement is efficiently performed and the water evaporation of the water-retaining agent can be promoted, there is an advantage that extremely excellent surface temperature reduction performance can be obtained. Have.

III. Water-retaining component The water-retaining component is selected from the following (A), (B) and (C) as described above: (A) Cross-linking with a polymer having a cross-linking functional moiety cross-linked with a cross-linking agent. A water-retaining component containing an agent and having a water-retaining gel-forming ability at room temperature; (B) containing a water-absorbent resin and a polysaccharide having a gel-forming ability in the presence of an alkali metal salt or an alkaline earth metal salt. , Water-retaining component; (C) A water-retaining component containing a water-absorbent resin and a resin emulsion. Each will be described below. For convenience, these are referred to as water retention-imparting components A, B or C, respectively.

III-A. Water retention component A
In the present embodiment, the polymer contained in the water-retaining component A forms a water-retaining gel together with the cross-linking agent at room temperature, and the water-retaining gel can realize water-retaining pavement.

The polymer has a crosslinkable functional moiety that is crosslinked with a crosslinking agent, and any suitable polymer having the ability to form a water-retaining gel at room temperature together with the crosslinking agent can be adopted. The number of crosslinkable functional portions (typically functional groups) of the polymer may be one or more (that is, it may have reactivity with the functional groups of the crosslinking agent) and is formed. It can be appropriately set according to the desired crosslink density, water absorption ratio, etc. for the water-retaining gel. Specific examples of the functional groups of the polymer include carboxy groups (at least some of the carboxy groups in the polymer may be neutralized with alkali (eg, sodium hydroxide)), (meth) acryloyl groups, amino groups, Examples thereof include a hydroxy group, an aromatic hydroxy group, a thiol group, an aromatic thiol group, an oxazoline group, an epoxy group, an aziridine group, an isocyanate group and a carbodiimide group. Typically, the functional group of the polymer is a functional group different from the functional group of the cross-linking agent. When the number of functional groups of the polymer is two or more, the polymer may contain two or more of the same functional groups, or may contain different functional groups. Polymers are typically water-soluble, water-dispersible or hydrophilic. Specific examples of the polymer include a carboxy group-containing polymer (for example, poly (meth) acrylic acid, a copolymer of a monomer copolymerizable with acrylic acid and an acrylic acid), and an amino group-containing polymer (for example, polyacrylamide and polyamine). Resins, polyamide polyamine resins, polyethyleneimines), epoxy group-containing polymers (eg, poly (meth) glycidyl acrylate, copolymers of monomers copolymerizable with (meth) glycidyl acrylate and glycidyl (meth) acrylate, Epoxy resin), oxazoline group-containing polymer (for example, product name "Epocross" manufactured by Nippon Catalyst Co., Ltd.), aziridine group-containing polymer (for example, product name "Chemitite" manufactured by Nippon Catalyst Co., Ltd.), isocyanate group-containing polymer (for example, DIC). Examples thereof include a product name “Bernock” manufactured by Nisshinbo Chemical Co., Ltd. and a polymer containing a carbodiimide group (for example, a product name “Carbodilite” manufactured by Nisshinbo Chemical Co., Ltd.). These polymers may be used alone or in combination of two or more. In addition, in this specification, "(meth) acrylic" means acrylic and / or methacryl.

The weight average molecular weight Mw of the polymer is preferably 1,000 to 2,000,000, more preferably 1,000 to 1,000,000. When the weight average molecular weight of the polymer is in such a range, it is possible to form a water-retaining gel having a desired water absorption ratio and capable of swelling and deswelling satisfactorily. Further, since the viscosity becomes appropriate when the polymer is used as a solution, a water-retaining agent having excellent handleability can be realized.

As used herein, the term "crosslinking agent" refers to a substance having two or more reactive functional groups in one molecule and linking the polymers by a reaction between the functional groups and, for example, a functional group of a polymer. The cross-linking agent may be a low molecular weight substance or a polymer. As the cross-linking agent, any suitable cross-linking agent having the ability to form a water-retaining gel at room temperature by cross-linking the polymer can be adopted. Specifically, the cross-linking agent has two or more functional groups capable of reacting with the functional groups of the polymer. As a result, a three-dimensional network structure of the polymer is formed with the cross-linking agent as a cross-linking point, and as a result, a water-retaining gel is formed. The number of functional groups of the cross-linking agent is preferably 2 to 1000, and more preferably 2 to 200. Specific examples of the functional group of the cross-linking agent include a carboxy group (at least a part of the carboxy group in the cross-linking agent may be neutralized with an alkali (for example, sodium hydroxide)), a (meth) acryloyl group, and an amino. Examples thereof include a group, a hydroxy group, an aromatic hydroxy group, a thiol group, an aromatic thiol group, an oxazoline group, an epoxy group, an aziridine group, an isocyanate group and a carbodiimide group. Typically, the functional group of the cross-linking agent is a functional group different from the functional group of the polymer. Specific examples of the cross-linking agent include a polyfunctional aziridine compound (for example, a product name "Chemitite" manufactured by Nippon Catalyst Co., Ltd.), a polyfunctional epoxy compound (for example, a product name "Denacol" manufactured by Nagase ChemteX Corporation), and a polyfunctional oxazoline. Compounds (for example, 2,2'-bis (2-oxazoline), 1,2-bis (2-oxazolin-2-yl) ethane, oxazoline group-containing polymer (for example, product name "Epocross" manufactured by Nippon Catalyst Co., Ltd.)) ), Polyfunctional carbodiimide compound (for example, product name "Carbodilite" manufactured by Nisshinbo Chemical Co., Ltd.), polyfunctional isocyanate compound (for example, tolylene diisocyanate (TDI), diphenylmethanediisocyanate (MDI)), polyfunctional (meth) acryloyl compound (for example). For example, alkylene bisacrylamide), polyfunctional carboxy compounds (eg, maleic acid, fumaric acid, itaconic acid, polyacrylic acid), polyfunctional amine compounds (eg, ethylenediamine, bis (hexamethylene) triamine) can be mentioned. These cross-linking agents may be used alone or in combination of two or more. Depending on the combination of functional groups, the polymer can also be used as a cross-linking agent. In addition, in this specification, for example, a "polyfunctional epoxy compound" means a compound having two or more functional groups called epoxy groups. The same applies to other polyfunctional compounds.

The preferred combination of the crosslinkable functional moiety of the polymer and the functional group of the crosslinker is as follows.

A more preferred combination of the crosslinkable functional moiety of the polymer and the functional group of the crosslinker is as follows.

Particularly preferred combinations of the crosslinkable functional moiety of the polymer and the functional group of the crosslinker are carboxy / oxazoline, carboxy / epoxy, amino / (meth) acryloyl, amino / epoxy.

Preferred combinations of polymers and cross-linking agents include amino group-containing polymers (eg, polyethyleneimine) / polyfunctional epoxy group-containing compounds (eg, alcandiol diglycidyl ethers, alcantriol triglycidyl ethers, eg, manufactured by Nagase ChemteX). Product name "Denacol")), amino group-containing polymer / polyfunctional acryloyl group-containing compound (for example, alkylenebisacrylamide), amino group-containing polymer / polyfunctional epoxy group-containing compound and polyfunctional acryloyl group-containing compound, carboxy group-containing polymer (For example, poly (meth) acrylic acid, a copolymer of a monomer copolymerizable with (meth) acrylic acid and (meth) acrylic acid) / polyfunctional oxazoline group-containing compound (for example, a product name manufactured by Nippon Catalyst Co., Ltd.) "Epocross"), carboxy group-containing polymers / polyfunctional epoxy group-containing compounds, carboxy group-containing polymers / polyfunctional oxazoline group-containing compounds and polyfunctional epoxy group-containing compounds.

The content of the polymer in the water-retaining agent for a porous pavement is, for example, 0.1% by mass to 50% by mass, preferably 0.5% by mass to 30% by mass, and more preferably 1% by mass. It is 10% by mass. When the content of the polymer is in such a range, a gel having a desired water absorption ratio can be formed.

The content of the cross-linking agent in the water-retaining agent for a porous pavement is, for example, 0.1% by mass to 30% by mass, preferably 0.5% by mass to 20% by mass, and more preferably 1% by mass. % To 10% by mass. When the content of the cross-linking agent is in such a range, a gel having a desired strength and stability can be formed.

The mass ratio (polymer / cross-linking agent) of the content of the polymer and the content of the cross-linking agent in the water-retaining agent for porous pavement is preferably 50/1 to 1/50, and more preferably 10 /. It is 1 to 1/5. When the ratio is within such a range, a gel having an excellent balance between water retention capacity and strength can be formed.

The molar ratio of the crosslinkable functional part of the polymer to the functional group of the crosslinker in the water-retaining agent for porous pavement (the number of moles of the crosslinkable functional part derived from the polymer / the number of moles of the functional group derived from the crosslinker) is , It is preferably 1/200 to 200/1, and more preferably 1/100 to 100/1. When the ratio is within such a range, a gel having an excellent balance between water retention capacity and strength can be formed.

When the water-retaining component A is used, the gelation time of the water-retaining agent for a porous pavement is preferably 30 minutes to 24 hours, more preferably 1 hour to 20 hours, and further preferably 2 hours. ~ 15 hours. If the gelation time is 30 minutes or more, the water-retaining agent for the porous pavement can be kept in a liquid state during the introduction work, so that an appropriate pot life can be secured. Therefore, it is possible to realize good handleability without worrying about deterioration of workability due to gelation of the water-retaining agent for porous pavement in the introduction work. On the other hand, if the gelation time is 24 hours or less, the gelation can be completed without taking an excessively long time. As a result, a water-retaining gel can be formed on the porous pavement in a practically appropriate time, and the water-retaining pavement can be manufactured. In the present specification, the “gelling time” refers to the time until the water-retaining agent for a porous pavement loses its fluidity and becomes solidified in appearance.

In the present embodiment, the water-retaining gel formed from the water-retaining agent for a porous pavement has a water absorption ratio of 0.5 g / g to 200 g / g in pure water for 1 hour, more preferably 0.5 g / g to 200 g / g. Is 1 g / g to 150 g / g, more preferably 2 g / g to 100 g / g. If the water absorption ratio is in such a range, good water retention performance can be realized.

III-B. Water retention component B
In the present embodiment, the water-absorbent resin contained in the water-retaining component B can function as a water-retaining material. The polysaccharide contained in the water-retaining component B has a gel-forming ability in the presence of an alkali metal salt or an alkaline earth metal salt, and the gel can function as a binder for holding a water-absorbent resin. That is, the gel formed from the water-retaining component B has a function different from that of the gel formed from the water-retaining component A (which functions as a water-retaining material).

As the water-absorbent resin, any suitable water-absorbent resin can be adopted. Specific examples include a crosslinked (co) weight having a polyoxyalkylene group such as an alkoxyalkylene glycol (meth) acrylate crosslinked copolymer and an alkoxypolyalkylene glycol (meth) acrylate / (meth) acrylic acid (salt) crosslinked copolymer. Combined; amide groups such as (meth) acrylamide / (meth) acrylic acid (salt) crosslinked copolymer, N-vinylacetamide crosslinked copolymer, N-vinylacetamide / (meth) acrylic acid (salt) crosslinked copolymer, etc. Cross-linked (co) copolymer having; cross-linked (co) polymer having an amino group such as polyallylamine cross-linked product, polyethyleneimine cross-linked product; hydroxyalkyl (meth) acrylate cross-linked polymer, hydroxyalkyl (meth) acrylate / (meth) Acrylic acid (salt) cross-linked copolymer, vinyl alcohol / (meth) acrylic acid (salt) cross-linked (co) polymer, etc. Cross-linked (co) copolymer having a hydroxyl group; 2-acrylamide / 2-methylpropanesulfonic acid (Salt) crosslinked copolymer, 2-acrylamide / 2-methylpropanesulfonic acid (salt) / (meth) acrylic acid (salt) crosslinked copolymer, sulfoalkyl (meth) acrylate (salt) crosslinked copolymer, sulfoalkyl (Meta) acrylate (salt) / (meth) acrylic acid (salt) crosslinked copolymer, crosslinked (co) copolymer having a sulfonic acid (salt) group such as sulfonated polystyrene crosslinked product; polyvinylsulfonic acid crosslinked product, mono A cross-linked (co) polymer having a phosphoric acid (salt) group such as a (2- (meth) acryloyloxyethyl) acid phosphate cross-linked (co) polymer; a cross-linked polyethylene oxide, a cross-linked polyvinylpyrrolidone, a cross-linked polyvinylpyridine, starch / poly (Meta) acrylonitrile graft copolymer saponified product, starch / poly (meth) acrylic acid (salt) graft copolymer crosslinked product, reaction product of polyvinyl alcohol and maleic anhydride (salt), isobutylene / maleic acid (salt) ) Cross-linked copolymers, betaine monomer (co) copolymers, and cross-linked copolymers of anionic and cationic monomers can be mentioned. The water-absorbent resin may be used alone or in combination of two or more. Further, the water-absorbent resin may be provided as a powder or as an aqueous dispersion.

In one embodiment, the water-absorbent resin can be provided as a microhydrogel aqueous dispersion. Hydrogel is a general term for substantially water-insoluble and water-swellable substances obtained by imparting a crosslinked structure to a water-soluble or hydrophilic polymer, and microhydrogel is a hydrogel having an average particle size of 100 μm or less. Point to. The microhydrogel aqueous dispersion is composed of, for example, an acrylonitrile-based polymer containing an acidic group and a crosslinked structure (hereinafter, acrylonitrile may be abbreviated as "AN" if necessary), and further hydrolyzes the nitrile group. A salt-type carboxyl group {-COOX (X: alkali metal or ammonium ion)} is introduced by the decomposition reaction, contains at least 0.1 mmol / g of salt-type carboxyl group, and is 100 μm or less in an absolute dry state. Examples thereof include hydrogels having an average particle size dispersed stably in an aqueous medium. According to such a water-absorbent resin, it is possible to maintain the water-retaining effect for a long period of time.

The AN-based polymer used as a starting material for obtaining a microhydrogel or an aqueous dispersion thereof is a polymer obtained by copolymerizing AN with one or more other ethylene-based unsaturated compounds. It is a general term for polymers containing an acidic group and a crosslinked structure. The content of AN in the AN-based polymer is preferably 30% by mass or more, more preferably 50% by mass or more, and further preferably 70% by mass or more with respect to the entire monomer. When the AN content is in such a range, a hydrogel having sufficient hydrophilicity and a desired water absorption rate can be formed.

As the ethylene-based unsaturated compound copolymerizing with AN, any suitable ethylene-based unsaturated compound can be adopted. Specific examples of the ethylenically unsaturated compound include vinyl halides such as vinyl chloride and vinylidene chloride and vinylidene halides; unsaturated alcohols such as allyl alcohol and methacrylic acid and their ethers; acrylic acid, methacrylic acid and the like. Unsaturated carboxylic acids and salts thereof; methacrylic acid esters such as methyl acrylate and ethyl acrylate; methacrylic acid esters such as methyl methacrylate and ethyl methacrylate; unsaturated ketones of methyl vinyl ketones and vinyl formate, Vinyl esters such as vinyl acetate; acrylamide and its alkyl substituents; N-methylol acrylamide; unsaturated hydrocarbon sulfonic acids such as p-styrene sulfonic acid and salts thereof; acrylic acids such as sulfobutyl acrylate and sulfoethyl methacrylate or Sulfoalkyl esters of methacrylic acid and salts thereof; styrenes such as styrene, α-methylstyrene and chlorosterene and alkyl or halogen substituents thereof; basic vinyl compounds such as vinylpyridine; vinyls such as methacrylonitrile and hydroxyethylacrylonitrile Nitrile compounds; vinyl aldehyde compounds such as achlorein and methacrylic acid; glycidyl esters of unsaturated carboxylic acids such as glycidyl acrylate and glycidyl methacrylate; glycidyl esters of unsaturated sulfonic acids such as glycidyl allyl sulfonate; vinyl glycidyl ether , Unsaturated glycidyl ethers such as allyl glycidyl ether; acrylic acid or methacrylic acid diesters such as ethylene glycol dimethacrylate, diethylene glycol methacrylate and diethylene glycol diacrylate; Methacrylic acid triesters; diallyl esters of polyvalent carboxylic acids such as diallylphthalate and diallylmalate; divinyl acid anhydrides such as anhydrous methacrylic acid; divinylbenzene and alkyl or halogen substituents thereof.

The average particle size of the water-absorbent resin in the powder (dry) state is, for example, 500 μm or less, preferably 200 μm or less, more preferably 100 μm or less, and further preferably 50 μm or less. If the average particle size is in such a range, the following advantages can be obtained, for example, when used as a water-retaining material for water-retaining pavement: (1) excellent fluidity, and as a result, excellent workability; (2) porosity. Good water retention performance can be achieved because it can penetrate into the voids of the pavement well; (3) Maintain water permeability and drainage because the voids of the porous pavement are not filled. (4) As a result of all of these, the water retention performance can be exhibited more effectively. On the other hand, the average particle size is, for example, 1 μm or more, preferably 5 μm or more. In the case of a water-absorbent resin previously dispersed in water such as a microhydrogel aqueous dispersion, the average particle size of the water-absorbent resin in a swollen state in water is, for example, 20000 μm or less, preferably 1000 μm or less. , More preferably 100 μm or less, still more preferably 10 μm or less. On the other hand, the average particle size in the swollen state is, for example, 0.02 μm or more.

The 1-hour water absorption ratio of the water-absorbent resin in pure water is preferably 10 g / g to 1000 g / g, more preferably 15 g / g to 700 g / g, and further preferably 20 g / g to 500 g / g. Is. If the water absorption ratio is in such a range, good water retention performance can be realized.

As the polysaccharide, any suitable polysaccharide having a gel-forming ability in the presence of an alkali metal salt or an alkaline earth metal salt can be used. Specific examples of polysaccharides include alginic acid and its salts or esters, guar gum derivatives such as carop bean gum (locust bean gum), guar gum, and hydroxypropyl guar gum, carrageenan, pectin, xanthan gum, gellan gum, dieutan gum, curdran, and tamarin seed gum. , Farselelan, Brulan, Glucomannan, Agar (agarose), Pectin, Brown algae extract, Gelatin, Collagen. The polysaccharides are preferably alginic acid and salts or esters thereof, hydroxypropyl guar gum, carrageenan, pectin, gellan gum, glucomannan, agar (agarose). These polysaccharides may be used alone or in combination of two or more.

Alkali metal salts or alkaline earth metal salts can typically function as catalysts for the gelation reaction of polysaccharides. Therefore, the alkali metal salt or the alkaline earth metal salt may be contained together with the polysaccharide in the water-retaining agent for the porous pavement, and the water-retaining agent for the porous pavement is imparted in the introduction work to the porous pavement. It may be in contact with an agent (substantially a polysaccharide). As the alkali metal salt, an organic salt or an inorganic salt of an alkali metal (typically lithium, sodium, potassium) can be used. As the alkaline earth metal salt, an organic salt or an inorganic salt of an alkaline earth metal (typically magnesium, calcium, strontium, barium) can be used. Specific examples of alkali metal salts and alkaline earth metal salts include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkaline earth such as calcium hydroxide, magnesium hydroxide and barium hydroxide. Metal hydroxides; chlorides such as lithium chloride, sodium chloride, potassium chloride, calcium chloride, magnesium chloride, barium chloride; carbonates such as sodium carbonate, potassium carbonate, calcium carbonate, magnesium carbonate, barium carbonate, lithium hydrogen carbonate, etc.; Sulfates such as sodium sulfate, potassium sulfate, calcium sulfate, magnesium sulfate, barium sulfate, lithium hydrogensulfate; nitrates such as lithium nitrate, sodium nitrate, potassium nitrate, calcium nitrate, magnesium nitrate, barium nitrate; lithium pyrophosphate, sodium phosphate , Potassium phosphate, sodium hydrogen phosphate, potassium hydrogen phosphate, barium hydrogen phosphate, lithium dihydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, calcium dihydrogen phosphate, trimagnesium phosphate, etc. Phosphate; borate; sodium acetate, potassium benzoate, calcium citrate, magnesium citrate, calcium ethylenediamine tetraacetate, magnesium ethylenediamine tetraacetate, calcium 1,3-propanediamine tetraacetate, 1,3-propanediamine tetra. Examples include organic acid salts such as magnesium acetate. The alkali metal salt or alkaline earth metal salt preferably has high water solubility. For example, the solubility of an alkali metal salt or an alkaline earth metal salt can be 1 g / 100 g or more of water. From this point of view, the alkali metal salt or alkaline earth metal salt is preferably lithium hydroxide, sodium hydroxide, potassium hydroxide, barium hydroxide, lithium chloride, sodium chloride, potassium chloride, calcium chloride, magnesium chloride. , Barium chloride, lithium carbonate, sodium carbonate, potassium carbonate, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, lithium nitrate, sodium nitrate, potassium nitrate, calcium nitrate, magnesium nitrate, barium nitrate, sodium phosphate, potassium phosphate, Sodium hydrogen phosphate, potassium hydrogen phosphate, lithium dihydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, calcium dihydrogen phosphate; more preferably lithium carbonate, sodium carbonate, potassium carbonate, sulfuric acid. Lithium, sodium sulfate, potassium sulfate, magnesium sulfate, lithium nitrate, sodium nitrate, potassium nitrate, calcium nitrate, magnesium nitrate, barium nitrate, sodium phosphate, potassium phosphate, sodium hydrogen phosphate, potassium hydrogen phosphate, dihydrogen phosphate Lithium, monosodium dihydrogen phosphate, potassium dihydrogen phosphate, calcium dihydrogen phosphate.

The content of the polysaccharide in the water-retaining agent for a porous pavement is, for example, 0.01% by mass to 30% by mass, preferably 0.05% by mass to 10% by mass, and more preferably 0. It is 1% by mass to 5% by mass. When the content of the polysaccharide is in such a range, good gelation is realized, and the water-absorbent resin can be appropriately and stably fixed to the porous pavement.

The content of the water-absorbent resin in the water-retaining agent for a porous pavement is, for example, 0.01% by mass to 30% by mass, preferably 0.05% by mass to 20% by mass, and more preferably 0. .1% by mass to 10% by mass. When the content of the water-absorbent resin is within such a range, good water-retaining power can be realized after being applied to a porous pavement or the like. Further, it is possible to secure the fluidity that can realize appropriate workability.

The ratio of the content of the polysaccharide to the content of the water-absorbent resin (polysaccharide / water-absorbent resin) in the water-retaining agent for porous pavement is preferably 1/99 to 99/1, more preferably. Is 5/95 to 95/5. When the ratio is in such a range, there is an advantage that the water-absorbent resin can be efficiently immobilized and water retention can be exhibited more efficiently.

Alkali metal salts or alkaline earth metal salts can be used in amounts that can properly function as catalysts for the gelation reaction. The amount of the alkali metal salt or alkaline earth metal salt used is, for example, 0.1 part by mass to 200 parts by mass, preferably 0.5 part by mass to 100 parts by mass, based on 100 parts by mass of the polysaccharide.

The water retention-imparting component B may further contain a resin emulsion. The resin emulsion can function as an auxiliary binder for polysaccharides. By using the polysaccharide and the resin emulsion together as the binder, it is possible to obtain an advantage that the water-absorbent resin can be more firmly fixed to the porous pavement and the decrease in water retention capacity can be suppressed. The resin emulsion will be described later in III-C.

When the water-retaining component B is used, the gelation time of the water-retaining agent for a porous pavement is preferably 30 minutes to 24 hours, more preferably 1 hour, as in the case of the water-retaining component A. It is ~ 20 hours, more preferably 2 hours ~ 15 hours. The effect of such gelation time is also the same as in the case of the water retention-imparting component A.

III-C. Water retention component C
In the present embodiment, the water-absorbent resin contained in the water-retaining component C can function as a water-retaining material, and the resin emulsion can function as a binder for holding the water-absorbent resin.

The water-absorbent resin is as described in III-B above with respect to the water-retaining component B.

The resin emulsion is typically a water-dispersible resin emulsion. The dispersion medium of the water-dispersible resin emulsion is water, and the dispersion medium is less likely to volatilize than a solvent-based binder (for example, a solvent-based adhesive). Therefore, the handleability and workability can be remarkably excellent as compared with the solvent-based binder. Further, since the odor and flammability are remarkably low as compared with the solvent-based binder, there is a great environmental advantage. Examples of the resin capable of forming particles in the emulsion include acrylic resin, epoxy resin, urethane resin, vinyl acetate resin, styrene butadiene latex, and ethylene vinyl acrylate. These may be used alone or in combination of two or more. The resin emulsion is preferably an acrylic resin emulsion. This is because it is easy to obtain and manufacture, and it is easy to adjust the characteristics by adjusting the type and compounding ratio of the monomer components. More preferably, the acrylic resin emulsion contains 15% by mass or more of an acrylic acid ester having an alkyl group having 4 or more carbon atoms in the monomer component, more preferably 25% by mass or more, and particularly preferably 35% by mass or more. Including.

The concentration of particles (solid content) formed in the resin emulsion is, for example, 10% by mass to 80% by mass, preferably 20% by mass to 70% by mass, and more preferably 30% by mass to 60% by mass. is there. When the concentration of the resin emulsion is within such a range, the productivity and handleability of the resin emulsion are excellent. Hereinafter, the resin particles formed in the emulsion may be simply referred to as resin particles or emulsion particles. The resin emulsion preferably contains a dispersion medium of 20% by mass to 80% by mass, more preferably 30% by mass to 80% by mass, and further preferably 40% by mass to 70% by mass. The dispersion medium contained in the resin emulsion preferably contains water as a main component. The ratio of water to the entire dispersion medium is preferably 50% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more.

The average particle size of the resin particles is, for example, 50 nm to 500 nm, preferably 80 nm to 400 nm, and more preferably 100 nm to 350 nm. When the average particle size of the resin particles is in such a range, there is an advantage that mechanical stability and water resistance are excellent.

The average particle size of the resin particles is preferably equal to or less than the average particle size of the water-absorbent resin (swelled state). The ratio of the average particle size of the resin particles to the average particle size of the water-absorbent resin (swelling state) [average particle size of the water-absorbent resin / average particle size of the resin particles] is, for example, 1/1 to 1000/1. It is preferably 2/1 to 750/1, and more preferably 3/1 to 500/1. When the ratio of the average particle size is in such a range, there is an advantage that the water-absorbent resin can be efficiently fixed and water retention can be exhibited more efficiently.

The minimum film-forming temperature (MFT: Minimum Film-forming Temperature) of the resin emulsion is, for example, 70 ° C. or lower, preferably 30 ° C. or lower, more preferably 10 ° C. or lower, and further preferably 0 ° C. or lower. .. On the other hand, the MFT can be, for example, −10 ° C. or higher, and practically 0 ° C. or higher. When the MFT is in such a range, good film formation is realized, so that the resin emulsion can function well as a binder.

The acid value of the resin emulsion is, for example, 156 or less, preferably 78 or less, and more preferably 39 or less. On the other hand, the acid value is, for example, 0.1 or more. When the acid value is in such a range, an emulsion having excellent stability can be formed.

The content of the resin particles in the water-retaining agent for a porous pavement is, for example, 0.01% by mass to 50% by mass, preferably 0.05% by mass to 40% by mass, and more preferably 0. It is 1% by mass to 30% by mass. When the content of the resin particles is within such a range, the water-absorbent resin can be appropriately fixed to the porous pavement.

The content of the water-absorbent resin in the water-retaining agent for porous pavement is as described in III-B above with respect to the water-retaining component B.

The ratio of the content of the resin particles to the content of the water-absorbent resin (resin particles / water-absorbent resin) in the water-retaining agent for a porous pavement is preferably 1/99 to 99/1, more preferably. Is 5/95 to 95/5. When the ratio is in such a range, there is an advantage that the water-absorbent resin can be efficiently immobilized and water retention can be exhibited more efficiently.

IV. Method for Producing Water-Retaining Pavement In the method for producing water-retaining pavement according to the embodiment of the present invention, the water-retaining agent for porous pavement according to the above I to III is applied, sprayed, injected or filled in the porous pavement. Including that.

The porous pavement is typically constructed on the surface of a road or the like. Examples of the porous pavement include a drainage asphalt mixture, a permeable asphalt mixture, a drainage cement concrete, and a permeable cement concrete pavement.

Hereinafter, the case where the water-retaining agent for a porous pavement contains a water-retaining component A, B or C will be briefly described. For convenience, the water-retaining agent for a porous pavement containing the water-retaining component A is referred to as "water-retaining agent A for a porous pavement". The same applies when the water-retaining agent for a porous pavement contains a water-retaining component B or C.

IV-A. Water retention agent for porous pavement A
The water-retaining agent A for a porous pavement is typically applied, sprayed, injected or filled in the constructed (cured) porous pavement. Specifically, the applied water-retaining agent A (liquid) for the porous pavement enters the voids of the porous pavement. The water-retaining agent A (substantially a polymer and a cross-linking agent) for a porous pavement can appropriately enter the voids of the porous pavement without any special operation. That is, according to the embodiment of the present invention, a technique for forming a water-retaining layer inside a porous pavement (for example, after spraying a water-absorbent resin on the surface of a porous pavement to form a water-retaining layer, the water-retaining layer is formed. It is possible to realize water-retaining pavement with remarkably excellent workability and remarkably low cost as compared with (technology for further constructing a porous pavement covering). Further, by adjusting the amount of coating or the like, the voids can be appropriately filled. The amount of the water-retaining agent A for the porous pavement such as the coating amount may be, for example, 0.2 liter to 7 liters with respect to ^{1 m 2 of the porous pavement.} If necessary, an operation may be performed to assist the water retention-imparting agent from entering the voids. Examples of such an operation include vibration and pressurization.

Next, the water-retaining agent A for a porous pavement is gelled. As described above, since the water-retaining agent A for a porous pavement has a gel-forming ability at room temperature and an appropriate gelation time, a water-retaining gel is formed on the porous pavement if left for a predetermined time. As described above, according to the embodiment of the present invention, the water-retaining pavement can be produced by the operation at room temperature. Heating may be carried out to promote gelation of the water-retaining agent A for a porous pavement and / or, if necessary (for example, in the case of winter). The heating temperature is preferably 50 ° C. to 100 ° C., more preferably 70 ° C. to 90 ° C. The heating time can vary depending on the heating temperature. The heating time can be, for example, 5 minutes to 2 hours. By forming the water-retaining gel, the voids of the porous pavement are typically filled with the jelly-like water-retaining gel. Therefore, the formed water-retaining gel does not substantially flow out of the porous pavement even when there is a large amount of rainfall, for example.

IV-B. Water retention agent B for porous pavement
The water-retaining agent B for a porous pavement may be mixed at the time of preparing the material (for example, the above-mentioned asphalt mixture, cement concrete) forming the porous pavement, and at the time of construction of the porous pavement (uncured). It may be introduced at the time), or it may be applied, sprayed, injected or filled in the constructed (after curing) porous pavement. Hereinafter, as an example, an embodiment of introducing the water-retaining agent B for a porous pavement into a porous pavement after construction will be described.

In the present embodiment, as in the case of the water-retaining agent A for the porous pavement, the water-retaining agent B for the porous pavement is introduced by applying, spraying, injecting or filling the porous pavement. .. The mechanism of introduction and its effect are as described in IV-A above with respect to the water retention imparting agent A for porous pavement.

Next, the porous pavement body to which the water retention-imparting agent B for the porous pavement body is applied, sprayed, injected or filled is cured. The gelation reaction of the polysaccharide proceeds by curing, and the water-absorbent resin is fixed to the porous pavement. As described above, since polysaccharides can be gelled at room temperature, natural curing (curing at room temperature) can be adopted as a curing method. As described above, according to the present embodiment, the water-absorbent resin can be fixed to the porous pavement by the operation at room temperature. If necessary (for example, in the case of winter), heat curing may be performed. The heating temperature in the case of heat curing is preferably 50 ° C. to 100 ° C., more preferably 70 ° C. to 90 ° C. The heating time can vary depending on the heating temperature. The heating time can be, for example, 5 minutes to 2 hours.

Since the water-absorbent resin is taken up and fixed in the three-dimensional network structure of the insoluble and insoluble gel in the porous pavement, it is fixed as compared with the case where it is fixed with a simple resin binder (for example, an adhesive or a solidified film). The degree of fixation is extremely strong and stable.

IV-C. Water retention agent C for porous pavement
The water-retaining agent C for a porous pavement is used at the time of preparing a material (for example, the above-mentioned asphalt mixture, cement concrete) for forming a porous pavement, as in the case of the water-retaining agent B for a porous pavement. It may be mixed, introduced at the time of construction (uncured) of the porous pavement, or applied, sprayed, injected or filled into the constructed (after curing) porous pavement. Hereinafter, as an example, an embodiment of introducing the water-retaining agent C for a porous pavement into a porous pavement after construction will be described.

In the present embodiment, as in the case of the water-retaining agents A and B for the porous pavement, the water-retaining agent C for the porous pavement is applied, sprayed, injected or filled in the porous pavement. Introduce. The mechanism of introduction and its effect are as described in IV-A above with respect to the water retention imparting agent A for porous pavement.

Next, the water-retaining agent C for a porous pavement is dried. By drying, the aqueous medium in the water-retaining agent C for the porous pavement evaporates, and the water-absorbent resin is fixed to the porous pavement by the resin emulsion. The drying is preferably natural drying. If necessary, it may be heat-dried. The heating temperature in the case of heat drying is preferably 50 ° C. to 100 ° C., more preferably 70 ° C. to 90 ° C. The heating time can vary depending on the heating temperature. The heating time can be, for example, 2 to 5 minutes. As described above, according to the present embodiment, the water-absorbent resin can be fixed to the porous pavement by the operation at normal temperature or not so high temperature.

Water-retaining pavements are manufactured from IV-A to IV-C.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The measurement method of each characteristic in the examples is as follows.

(1) Surface temperature reduction performance The water-retaining specimens obtained in Examples and Comparative Examples were immersed in water for 1 day to sufficiently absorb water, and then the surface temperature reduction performance was evaluated by a lamp irradiation test. Specifically, the surface temperature of the water-retaining specimen after irradiation is measured by irradiating the water-retaining specimen with a lamp in accordance with the method described in the "Water-retaining pavement" technical data published by the Road Surface Temperature Rise Suppression Pavement Study Group. It was measured. On the other hand, the porous asphalt specimen into which the water-retaining agent was not introduced was also irradiated with a lamp in the same manner, and the surface temperature of the specimen after the irradiation was measured. The difference between the surface temperature of the porous asphalt specimen and the surface temperature of the water-retaining specimen was defined as the surface temperature reduction performance.

<Example 1>
Polyethylene imine (manufactured by Nippon Catalyst Co., Ltd., product name "Epomin P-1000", weight average molecular weight Mw: 70,000, non-volatile content: 30% by mass) 33.3 parts by mass and polyethylene glycol diglycidyl ether (Nagase Chemtex Co., Ltd.) Made by the company, product name "Denacol EX-830") 6.2 parts by mass is dissolved in 210.4 parts by mass of water, and magnesium oxide (manufactured by Kyowa Chemical Industry Co., Ltd., product name "Kyowa Mag 30") 27.8 mass After adding and dispersing, 2.1 parts by mass of hydroxyethyl cellulose (manufactured by Daicel FineChem, product name "SE-850") was added as a thickener to prevent precipitation of magnesium oxide, and the mixture was stirred for 1 minute to impart water retention. Agent 1 was prepared.

The sides and bottom of the porous asphalt specimen (length 15 cm × width 15 cm × thickness 5 cm) were covered with a vinyl sheet, and the water-retaining agent obtained above was poured into the porous asphalt specimen to fill the voids of the specimen. Then, the specimen was cured at room temperature for 1 day, and then the covering vinyl sheet was peeled off to remove the protruding water-retaining agent to obtain a water-retaining specimen 1. The obtained water-retaining specimen 1 was subjected to the evaluation of (1) above. The results are shown in Table 3.

<Example 2>
The water retention-imparting agent 2 was prepared in the same manner as in Example 1 except that the amount of magnesium oxide used was 62.5 parts by mass. A water-retaining specimen 2 was obtained in the same manner as in Example 1 except that the water-retaining agent 2 was used. The obtained water-retaining specimen 2 was subjected to the same evaluation as in Example 1. The results are shown in Table 3.

<Example 3>
The water retention imparting agent 3 was prepared in the same manner as in Example 1 except that 27.8 parts by mass of alumina powder was used instead of 27.8 parts by mass of magnesium oxide. A water-retaining specimen 3 was obtained in the same manner as in Example 1 except that the water-retaining agent 3 was used. The obtained water-retaining specimen 3 was subjected to the same evaluation as in Example 1. The results are shown in Table 3.

<Example 4>
Polyethylene imine (manufactured by Nippon Catalyst Co., Ltd., product name "Epomin P-1000", weight average molecular weight Mw: 70,000, non-volatile content: 30% by mass) 33.3 parts by mass and polyethylene glycol diglycidyl ether (Nagase Chemtex Co., Ltd.) Company-made product name "Denacol EX-830") 6.2 parts by mass is dissolved in 210.4 parts by mass of water, and 1.3 parts by mass of carbon black (manufactured by Mitsubishi Chemical, product name "MA100") is added while stirring. In addition, the water-retaining agent 4 was prepared by stirring for 3 minutes. A water-retaining specimen 4 was obtained in the same manner as in Example 1 except that the water-retaining agent 4 was used. The obtained water-retaining specimen 4 was subjected to the same evaluation as in Example 1. The results are shown in Table 3.

<Example 5>
The water retention imparting agent 5 was prepared in the same manner as in Example 4 except that the amount of carbon black used was 5.1 parts by mass. A water-retaining specimen 5 was obtained in the same manner as in Example 1 except that the water-retaining agent 5 was used. The obtained water-retaining specimen 5 was subjected to the same evaluation as in Example 1. The results are shown in Table 3.

<Example 6>
Polyethylene imine (manufactured by Nippon Catalyst Co., Ltd., product name "Epomin P-1000", weight average molecular weight Mw: 70,000, non-volatile content: 30% by mass) 26.7 parts by mass and polyethylene glycol diglycidyl ether (Nagase Chemtex Co., Ltd.) Made by the company, product name "Denacol EX-830") 5.0 parts by mass is dissolved in 168.4 parts by mass of water, and magnesium oxide (manufactured by Kyowa Chemical Industry Co., Ltd., product name "Kyowa Mag 30") 85.7 mass After adding 0.6 parts by mass of parts and carbon black (manufactured by Mitsubishi Chemical, product name "MA100") and dispersing, hydroxyethyl cellulose (manufactured by Daicel FineChem, product name "SE-"" as a thickener to prevent precipitation of magnesium oxide. 850 ”) 0.9 parts by mass was added and stirred for 1 minute to prepare a water retention imparting agent 6. A water-retaining specimen 6 was obtained in the same manner as in Example 1 except that the water-retaining agent 6 was used. The obtained water-retaining specimen 6 was subjected to the same evaluation as in Example 1. The results are shown in Table 3.

<Example 7>
Polyethylene imine (manufactured by Nippon Catalyst Co., Ltd., product name "Epomin P-1000", weight average molecular weight Mw: 70,000, non-volatile content: 30% by mass) 33.3 parts by mass and polyethylene glycol diglycidyl ether (Nagase Chemtex Co., Ltd.) Company manufactured product name "Denacol EX-830") 6.2 parts by mass dissolved in 210.4 parts by mass of water and rock wool (manufactured by Nippon Rock Wool Co., Ltd., product name "S Fiber FF") 5 .1 part by mass and 1.3 parts by mass of carbon black (manufactured by Mitsubishi Chemical, product name "MA100") were added and dispersed, and then hydroxyethyl cellulose (manufactured by Daicel FineChem, product name) was used as a thickener to prevent rock wool from settling. "SE-850") 2.1 parts by mass was added, and the mixture was stirred for 1 minute to prepare a water retention imparting agent 7. A water-retaining specimen 7 was obtained in the same manner as in Example 1 except that the water-retaining agent 7 was used. The obtained water-retaining specimen 7 was subjected to the same evaluation as in Example 1. The results are shown in Table 3.

<Comparative example 1>
The water retention-imparting agent C1 was prepared in the same manner as in Example 1 except that magnesium oxide was not used. A water-retaining specimen C1 was obtained in the same manner as in Example 1 except that the water-retaining agent C1 was used. The obtained water-retaining specimen C1 was subjected to the same evaluation as in Example 1. The results are shown in Table 3.

As is clear from Table 3, according to the examples of the present invention, by adding a specific powder to the water-retaining agent, it is possible to remarkably suppress an increase in the surface temperature of asphalt.

The water-retaining agent for a porous pavement of the present invention can easily realize a water-retaining pavement having good water-retaining performance, and can remarkably suppress an increase in the pavement surface temperature. The water-retaining pavement obtained by using the water-retaining agent for a porous pavement of the present invention can be suitably used for suppressing an increase in road surface temperature and alleviating the heat island phenomenon.

Claims (6)

A water-retaining agent for a porous pavement, which comprises a powder having a pavement surface temperature reducing ability and at least one water-retaining component selected from the following (A), (B) and (C):
(A) A water-retaining component containing a polymer having a crosslinkable functional portion crosslinked with a cross-linking agent and a cross-linking agent and having a water-retaining gel-forming ability at room temperature;
(B) A water-retaining component containing a water-absorbent resin and a polysaccharide having a gel-forming ability in the presence of an alkali metal salt or an alkaline earth metal salt;
(C) A water-retaining component containing a water-absorbent resin and a resin emulsion. The water retention imparting for a porous pavement according to claim 1, wherein the powder having the ability to reduce the surface temperature of the pavement has at least one property selected from the following (a), (b) and (c). Agent:
(A) Thermal conductivity is greater than 0.74 (W / m · K);
(B) Whiteness is 65% or more;
(C) The water content is 10% or more. The powder having the ability to reduce the pavement surface temperature is carbon black, magnesium oxide, zinc oxide, aluminum oxide, calcium carbonate, magnesium hydroxide, magnesium carbonate, titanium oxide, aluminum hydroxide, barium sulfate, talc, clay, kaolin, The water-retaining agent for a porous pavement according to claim 2, which is at least one selected from the group consisting of wollastonite, calcium silicate, permiculite, attapargite, sepionite, bentonite and montmorillonite. Any of claims 1 to 3, wherein the powder having the ability to reduce the pavement surface temperature is contained in a ratio of 1.0 part by mass to 2000 parts by mass with respect to 100 parts by mass of the solid content of the water retention component. The water-retaining agent for a porous pavement according to. The water-retaining agent for a porous pavement according to any one of claims 1 to 4, further comprising a thickener. A method for producing a water-retaining pavement, which comprises applying, spraying, injecting or filling the water-retaining agent for a porous pavement according to any one of claims 1 to 5 to the porous pavement.