WO2025127123A1 - Carbon-dioxide-fixing surface coating material, surface coating method for civil engineering structure and building structure, civil engineering structure, and building structure - Google Patents

Abstract

A carbon-dioxide-fixing surface coating material (10) according to the present invention comprises an adhesive layer (11), is used by being attached to a surface of a civil engineering structure or a building structure, and absorbs and fixes carbon dioxide in the atmosphere. A surface coating method according to the present invention includes a step of attaching the carbon-dioxide-fixing surface coating material (10) of the present invention to a surface of a civil engineering structure or a building structure. Another surface coating method according to the present invention includes: a step of attaching a carbon-dioxide-fixing surface coating material of the present invention composed of an adhesive layer to a surface of a civil engineering structure or a building structure; and a step of attaching a base material to a surface of the carbon-dioxide-fixing surface coating material attached to the civil engineering structure or the building structure. A civil engineering structure and a building structure according to the present invention have the carbon-dioxide-fixing surface coating material of the present invention attached thereto.

Description

Carbon dioxide fixation surface coating material, surface coating method for civil engineering structures and architectural structures, civil engineering structures, and architectural structures

The present invention relates to a carbon dioxide fixing surface coating material, a surface coating method for civil engineering structures and architectural structures, civil engineering structures, and architectural structures.

Since the Industrial Revolution, the use of fossil fuels has increased, and as a result, the concentration of carbon dioxide in the atmosphere has also increased. Carbon dioxide in the atmosphere accelerates global warming, so there is a desire to reduce carbon dioxide emissions in order to suppress the increase in the concentration of carbon dioxide in the atmosphere. In addition to reducing carbon dioxide emissions, there are also methods for reducing the concentration of carbon dioxide in the atmosphere, such as absorbing carbon dioxide in the atmosphere. One method for absorbing carbon dioxide in the atmosphere is, for example, to apply a water glass paint composition that has the ability to absorb carbon dioxide to the object to be coated (see Patent Document 1). The coating film formed by applying the water glass paint composition to the object to be coated absorbs carbon dioxide and forms polymerized silica. This allows the coating film to absorb carbon dioxide in the atmosphere.

International Publication No. 2012/077344

However, when attempting to form a coating film that absorbs carbon dioxide in the atmosphere using the water glass coating composition described in Patent Document 1, problems arise in that it takes a certain amount of time to apply the coating, and the penetration depth of the coating is not uniform, and therefore the amount of carbon dioxide absorbed is not constant.
Therefore, an object of the present invention is to provide a carbon dioxide fixing surface coating material that can simply and efficiently form a film that absorbs carbon dioxide in the atmosphere, a surface coating method for civil engineering structures and architectural structures that uses the carbon dioxide fixing surface coating material, and civil engineering structures and architectural structures that use the carbon dioxide fixing surface coating material.

ここで、Ｐは標準気圧（１０１３２５Ｐａ）であり、Ｖｄはデシケーターの容積（７Ｌ）であり、Ｒは気体定数（８３１０Ｐａ・Ｌ／（Ｋ・ｍｏｌ））であり、Ｔは測定温度（２９６Ｋ）であり、ΔＤは２４時間経過後のデシケーター内のＣＯ_２濃度とデシケーター内のＣＯ_２濃度の初期濃度との間の差の濃度（ｖｏｌ％）であり、Ｖｓはデシケーターに入れた二酸化炭素固定表面被覆材の体積（ｍ^３）である。
［３］前記粘着剤層は１種類以上の二酸化炭素固定剤を含む上記［１］又は［２］に記載の二酸化炭素固定表面被覆材。
[４]前記二酸化炭素固定剤が塩基性化合物である上記［３］に記載の二酸化炭素固定表面被覆材。
[５]前記二酸化炭素固定剤がアルカリ土類金属の水酸化物である上記［３］又は［４］に記載の二酸化炭素固定表面被覆材。
［６］前記二酸化炭素固定剤が水酸化カルシウムである上記［３］～［５］のいずれか１つに記載の二酸化炭素固定表面被覆材。
［７］前記粘着剤層の厚みが１００μｍ以上である上記［１］～［６］のいずれか１つに記載の二酸化炭素固定表面被覆材。
［８］前記粘着剤層が光硬化性樹脂により形成されている上記［１］～［７］のいずれか１つに記載の二酸化炭素固定表面被覆材。
［９］前記粘着剤層がアクリル系粘着剤により形成されている上記［１］～［８］のいずれか１つに記載の二酸化炭素固定表面被覆材。
［１０］基材をさらに備える上記［１］～［９］のいずれか１つに記載の二酸化炭素固定表面被覆材。
［１１］上記［１］～［１０］のいずれか１つに記載の二酸化炭素固定表面被覆材を、土木構造物又は建築構造物の表面に貼付する工程を含む土木構造物及び建築構造物の表面被覆工法。
［１２］前記土木構造物又は前記建築構造物に貼付した前記二酸化炭素固定表面被覆材の前記土木構造物又は前記建築構造物の表面側の反対側の表面に基材を貼付する工程をさらに含む上記［１１］に記載の表面被覆工法。
［１３］上記［１］～［１０］のいずれか１つに記載の二酸化炭素固定表面被覆材が貼付された土木構造物。
［１４］上記［１］～［１０］のいずれか１つに記載の二酸化炭素固定表面被覆材が貼付された建築構造物。 As a result of extensive research, the inventors discovered that the above problem could be solved by attaching an adhesive tape that absorbs carbon dioxide in the atmosphere instead of applying paint that absorbs carbon dioxide in the atmosphere, and thus completed the present invention.
The present invention provides the following [1] to [12].
[1] A carbon dioxide fixation surface covering material that has an adhesive layer, is attached to the surface of a civil engineering structure or an architectural structure, and absorbs and fixes carbon dioxide in the atmosphere.
[2] The carbon dioxide fixation surface coating material according to claim 1, wherein when the carbon dioxide absorption amount of the carbon dioxide fixation surface coating material is measured by the carbon dioxide absorption amount measurement method described below, the carbon dioxide absorption amount per unit volume of the carbon dioxide fixation surface coating material is 3 kg/ ^m3 or more 24 hours after the start of measurement.
<Method for measuring carbon dioxide absorption>
In a 23°C environment, the carbon dioxide fixing surface coating material attached to a SUS plate and the _CO2 concentration meter are placed in a desiccator so that the carbon dioxide fixing surface coating material does not come into contact with the inner surface of the desiccator or the _CO2 concentration meter. The desiccator is then evacuated to -0.040 MPa, a carbon dioxide gas cylinder is connected to the desiccator, and _CO2 is injected into the desiccator until the internal pressure of the desiccator reaches 0.000 MPa. The _CO2 concentration measured with the _CO2 concentration meter in the desiccator 10 minutes after the start of injection is defined as the initial concentration, and the _CO2 concentration in the desiccator 24 hours after the initial concentration measurement is measured with the _CO2 concentration meter. The amount of carbon dioxide absorbed per unit volume of the carbon dioxide fixing surface coating material is calculated using the following formula (1):

Here, P is standard atmospheric pressure (101,325 Pa), Vd is the volume of the desiccator (7 L), R is the gas constant (8,310 Pa·L/(K·mol)), T is the measurement temperature (296 K), ΔD is the difference in concentration (vol%) between the _CO2 concentration in the desiccator after 24 hours and the initial _CO2 concentration in the desiccator, and Vs is the volume ( ^m3 ) of the carbon dioxide fixing surface coating material placed in the desiccator.
[3] The carbon dioxide fixing surface covering material according to the above [1] or [2], wherein the pressure-sensitive adhesive layer contains one or more types of carbon dioxide fixing agents.
[4] The carbon dioxide fixing surface coating material according to the above [3], wherein the carbon dioxide fixing agent is a basic compound.
[5] The carbon dioxide fixing surface coating material according to the above [3] or [4], wherein the carbon dioxide fixing agent is an alkaline earth metal hydroxide.
[6] The carbon dioxide fixing surface coating material according to any one of the above [3] to [5], wherein the carbon dioxide fixing agent is calcium hydroxide.
[7] The carbon dioxide fixing surface covering material according to any one of the above [1] to [6], wherein the thickness of the pressure-sensitive adhesive layer is 100 μm or more.
[8] The carbon dioxide fixing surface covering material according to any one of the above [1] to [7], wherein the pressure-sensitive adhesive layer is formed from a photocurable resin.
[9] The carbon dioxide fixing surface covering material according to any one of the above [1] to [8], wherein the pressure-sensitive adhesive layer is formed from an acrylic pressure-sensitive adhesive.
[10] The carbon dioxide fixation surface covering material according to any one of [1] to [9] above, further comprising a substrate.
[11] A surface coating method for civil engineering structures and architectural structures, comprising a step of attaching the carbon dioxide fixation surface coating material according to any one of [1] to [10] above to the surface of the civil engineering structure or architectural structure.
[12] The surface coating method described in [11] above, further comprising a step of attaching a substrate to the surface of the civil engineering structure or the architectural structure opposite the surface side of the carbon dioxide fixing surface coating material attached to the civil engineering structure or the architectural structure.
[13] A civil engineering structure to which the carbon dioxide fixation surface covering material according to any one of [1] to [10] above has been affixed.
[14] An architectural structure to which the carbon dioxide fixation surface covering material according to any one of [1] to [10] above has been affixed.

The present invention provides a carbon dioxide fixing surface coating material that can easily and efficiently form a film that absorbs carbon dioxide in the atmosphere, a surface coating method for civil engineering structures and architectural structures that uses the carbon dioxide fixing surface coating material, and civil engineering structures and architectural structures that use the carbon dioxide fixing surface coating material.

FIG. 1 is a schematic diagram showing an example of the configuration of the carbon dioxide fixing surface covering material of the present invention. FIG. 2 is a schematic diagram showing an example of the configuration of the carbon dioxide fixation surface covering material of the present invention.

[Carbon dioxide fixing surface coating material]
The carbon dioxide fixing surface coating material of the present invention has an adhesive layer, is attached to the surface of a civil engineering structure or an architectural structure, and absorbs and fixes atmospheric carbon dioxide. As a result, the carbon dioxide fixing surface coating material of the present invention can easily and efficiently form a film that absorbs atmospheric carbon dioxide. Here, absorbing and fixing atmospheric carbon dioxide means that the carbon dioxide fixing surface coating material reacts with atmospheric carbon dioxide to generate a reaction product and retains the reaction product in the carbon dioxide fixing surface coating material, or that the carbon dioxide fixing surface coating material adsorbs atmospheric carbon dioxide and retains the adsorbed carbon dioxide in the carbon dioxide fixing surface coating material. In addition, the carbon dioxide fixing surface coating material of the present invention can suppress deterioration of civil engineering structures and architectural structures caused by the intrusion of deterioration factors such as chloride ions, and can also extend the life of civil engineering structures and architectural structures.

(Adhesive Layer)
<Adhesive>
The adhesive layer is preferably formed from an adhesive. The type of adhesive is not particularly limited, but examples include acrylic adhesives, rubber adhesives, urethane adhesives, and silicone adhesives. These may be used alone or in combination. Among these, the adhesive layer is preferably formed from an acrylic adhesive. By using an acrylic adhesive, it becomes easier to control the molecular weight of the adhesive, and the flexibility of the adhesive is increased to make it easier to follow the unevenness of the adherend surface, making it easier to attach the carbon dioxide fixing surface covering material to the surface of civil engineering structures and architectural structures.

The adhesive layer is preferably formed from a photocurable resin. That is, the adhesive layer may be formed by photocuring a photocurable adhesive composition as described below. The adhesive layer can be appropriately cured by being formed from a photocurable resin. In addition, by using a photocurable resin for the adhesive layer, it is easy to form a thick film of 100 μm or more. By forming the adhesive layer into a thick film, it is possible to attach the adhesive layer to the surface of a civil engineering structure or an architectural structure with high adhesive strength, and therefore it is possible to protect the surface of the civil engineering structure or the architectural structure for a long period of time.
The adhesive layer is preferably formed from an acrylic adhesive among photocurable resins. Note that the adhesive layer formed from a photocurable resin may be formed by using a photocurable main polymer for the adhesive, and for example, in the case of an acrylic adhesive, the acrylic polymer may be photocurable.

(Acrylic adhesive)
The acrylic pressure-sensitive adhesive is a pressure-sensitive adhesive containing an acrylic polymer obtained by polymerizing a polymerizable monomer including a (meth)acrylic acid alkyl ester monomer (A).
In this specification, the term "(meth)acrylic acid alkyl ester" refers to a concept including both acrylic acid alkyl ester and methacrylic acid alkyl ester, and the same applies to other similar terms. Furthermore, the term "polymerizable monomer" refers to a concept including not only a compound having no repeating unit, but also a monomer itself having a repeating unit, such as the olefin polymer (C) described later, so long as it is a compound that can be copolymerized with the (meth)acrylic acid alkyl ester monomer (A).

((Meth)acrylic acid alkyl ester monomer (A))
The (meth)acrylic acid alkyl ester monomer (A) is an ester of (meth)acrylic acid and an aliphatic alcohol, and is preferably an alkyl ester derived from an aliphatic alcohol in which the carbon number of the alkyl group of the aliphatic alcohol is preferably 2 to 14, more preferably 4 to 10. When the carbon number of the alkyl group is within this range, the adhesive strength is easily increased, and the storage modulus at 23° C. of the adhesive described below is easily adjusted to a predetermined range.

Specific examples of the (meth)acrylic acid alkyl ester monomer (A) include ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, and tetradecyl (meth)acrylate.
Of these, n-butyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and n-octyl (meth)acrylate are preferred, with 2-ethylhexyl (meth)acrylate being more preferred.
The (meth)acrylic acid alkyl ester monomers may be used alone or in combination of two or more kinds.

The constituent unit derived from the (meth)acrylic acid alkyl ester monomer (A) constitutes the main component in the adhesive layer, and its content is generally 30% by mass or more, preferably 40% by mass or more, more preferably 50% by mass or more based on the total amount of the adhesive layer.In this way, by increasing the content of the (meth)acrylic acid alkyl ester monomer (A), it is possible to impart the desired adhesive strength to the adhesive layer.In addition, the content of the constituent unit derived from the (meth)acrylic acid alkyl ester monomer (A) is, for example, 95% by mass or less, preferably 90% by mass or less, more preferably 80% by mass or less in order to contain a certain amount or more of other components.
The content of the constituent unit derived from the (meth)acrylic acid alkyl ester monomer (A) in the pressure-sensitive adhesive layer is substantially the same as the content of the (meth)acrylic acid alkyl ester monomer (A) in the pressure-sensitive adhesive composition described below, and can be expressed by replacing the content of the (meth)acrylic acid alkyl ester monomer (A). The same applies to components other than the component (A), such as the components (B) and (C) described below.

(Polar Group-Containing Vinyl Monomer (B))
The polymerizable monomer preferably contains a polar group-containing vinyl monomer (B) in addition to the (meth)acrylic acid alkyl ester monomer (A). The polar group-containing vinyl monomer (B) has a polar group and a vinyl group. By using the polar group-containing monomer (B), the adhesive strength to the adherend is easily improved.
Examples of the polar group-containing vinyl monomer (B) include carboxylic acid vinyl esters such as vinyl acetate, carboxylic acids containing a vinyl group such as (meth)acrylic acid and itaconic acid, and their anhydrides, vinyl monomers having a hydroxyl group such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone-modified (meth)acrylate, polyoxyethylene (meth)acrylate, and polyoxypropylene (meth)acrylate, and nitrogen-containing vinyl monomers such as (meth)acrylonitrile, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinyllaurolactam, (meth)acryloylmorpholine, (meth)acrylamide, dimethyl(meth)acrylamide, N-methylol(meth)acrylamide, N-butoxymethyl(meth)acrylamide, and dimethylaminomethyl(meth)acrylate.
From the viewpoint of adhesion to steel structures, among these, vinyl group-containing carboxylic acids such as (meth)acrylic acid and itaconic acid, and their anhydrides, and nitrogen-containing vinyl monomers such as (meth)acryloylmorpholine are preferred, (meth)acrylic acid and (meth)acryloylmorpholine are more preferred, and acrylic acid is even more preferred. Also, from the viewpoint of adhesion to concrete structures, among these, nitrogen-containing vinyl monomers such as (meth)acryloylmorpholine are preferred, (meth)acryloylmorpholine is more preferred, and acryloylmorpholine (ACMO) is even more preferred. These polar group-containing vinyl monomers (B) may be used alone or in combination of two or more.

When a polar group-containing vinyl monomer (B) is used, the content of the constituent units derived from the polar group-containing vinyl monomer (B) in the adhesive layer is preferably 1 to 20 parts by mass, more preferably 1 to 15 parts by mass, even more preferably 2 to 15 parts by mass, even more preferably 2 to 12 parts by mass, even more preferably 3 to 12 parts by mass, and even more preferably 3 to 10 parts by mass, per 100 parts by mass of the constituent units derived from the (meth)acrylic acid alkyl ester monomer (A). By setting the content of the polar group-containing vinyl monomer (B) within this range, it becomes easier to improve the adhesive strength of the carbon dioxide fixing surface coating material.

(Olefin polymer (C))
The polymerizable monomer preferably further contains an olefin polymer (C) having a polymerizable bond at one end. By using such an olefin polymer (C), the adhesive strength of the carbon dioxide fixing surface coating material can be easily improved.
The polymerizable bond means an unsaturated carbon-carbon bond capable of polymerizing with a polymerizable monomer, and examples thereof include an unsaturated double bond, and preferably a (meth)acryloyl group.
The olefin polymer (C) may be a polyolefin having a (meth)acryloyl group at one end. The polyolefin is a polymer of an aliphatic hydrocarbon compound having a double bond, such as ethylene, propylene, butane, butadiene, isoprene, or the like, or a hydrogenated product thereof.

Examples of polyolefins having a (meth)acryloyl group at one end include polyethylene having a (meth)acryloyl group at one end, which is prepared by reacting polyethylene having an epoxy group at one end with (meth)acrylic acid. Other examples include polybutadiene having a (meth)acryloyl group at one end or a hydrogenated product thereof, and examples of commercially available products include "L-1253" manufactured by Kuraray Co., Ltd.

The number average molecular weight of the olefin polymer (C) is preferably 500 to 20000, more preferably 1000 to 10000. The number average molecular weight may be measured by gel permeation chromatography (GPC) and calculated using a calibration curve of standard polystyrene.
In addition, the content of the structural unit derived from the olefin polymer (C) in the pressure-sensitive adhesive layer is preferably 1 to 20 parts by mass, more preferably 2 to 15 parts by mass, and even more preferably 4 to 12 parts by mass, per 100 parts by mass of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A).

(Crosslinking Agent (D))
The polymerizable monomer preferably further contains a crosslinking agent. The crosslinking agent may be a polyfunctional monomer having two or more vinyl groups, and preferably a polyfunctional (meth)acrylate having two or more (meth)acryloyl groups. The use of a polyfunctional monomer makes it easier to adjust the adhesive strength of the adhesive layer to an appropriate range.
The polyfunctional (meth)acrylate is not particularly limited, and examples thereof include bifunctional alkyl (meth)acrylates such as hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, ethoxylated trimethylolpropane triacrylate, proxied trimethylolpropane triacrylate, proxied glyceryl triacrylate, neopentyl glycol adipate diacrylate, and the like, as well as polymers such as polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and liquid hydrogenated 1,2-polybutadiene di(meth)acrylate. Among these polyfunctional (meth)acrylates, polymers are preferred, and liquid hydrogenated 1,2-polybutadiene diacrylate is more preferred. An example of a commercially available liquid hydrogenated 1,2-polybutadiene diacrylate is "TEAI-1000" manufactured by Nippon Soda Co., Ltd. In addition, bifunctional alkyl (meth)acrylates are also preferred, and an example of a commercially available product is A-HD-N of the NK Ester series manufactured by Shin-Nakamura Chemical Co., Ltd.
In addition, the content of the structural unit derived from the crosslinking agent in the pressure-sensitive adhesive layer is preferably 0.005 to 1 part by mass, more preferably 0.01 to 0.1 part by mass, and even more preferably 0.02 to 0.08 part by mass, relative to 100 parts by mass of the structural unit derived from the (meth)acrylic acid alkyl ester monomer (A).

(Tackifier resin)
The acrylic adhesive may contain a tackifier resin from the viewpoint of improving adhesive strength. As the tackifier resin, a tackifier resin having low polymerization inhibition properties, such as hydrogenated terpene resin, hydrogenated rosin, disproportionated rosin resin, petroleum resin, etc., is preferable. Among these, hydrogenated tackifier resins are preferable because tackifier resins having many double bonds inhibit polymerization reactions, and hydrogenated petroleum resins are particularly preferable.
From the viewpoint of improving the cohesive strength and adhesive strength of the adhesive, the softening point of the tackifier resin may be about 95° C. or higher, but preferably includes one having a softening point of 120° C. or higher, and for example, one having a softening point of 95° C. or higher but lower than 120° C. may be used in combination with one having a softening point of 120° C. or higher but lower than 150° C. The softening point may be measured by the ring and ball method specified in JIS K2207.
The content of the tackifier resin in the acrylic pressure-sensitive adhesive is preferably 5 to 40 parts by mass, more preferably 7 to 35 parts by mass, and even more preferably 10 to 25 parts by mass, relative to 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A).

(fine particles)
The acrylic adhesive may contain fine particles, which can improve the adhesive strength.
Examples of the fine particles include inorganic hollow particles such as glass balloons, shirasu balloons, and fly ash balloons; organic hollow particles made of polymethyl methacrylate, acrylonitrile-vinylidene chloride copolymers, polystyrene, and phenolic resins; inorganic fine particles such as glass beads, silica beads, and synthetic mica; and organic fine particles such as polyethyl acrylate, polyurethane, polyethylene, and polypropylene.
The content of the fine particles in the acrylic pressure-sensitive adhesive is preferably 0.1 to 15 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 0.7 to 7 parts by mass, based on 100 parts by mass of the structural units derived from the (meth)acrylic acid alkyl ester monomer (A).

(Other ingredients)
The acrylic adhesive used in the adhesive layer may contain, in addition to the components described above, various additives conventionally used in adhesives, such as plasticizers, softeners, pigments, dyes, polymerization initiators, flame retardants, and thickeners.

(Rubber adhesive)
Next, the rubber-based adhesive used in the adhesive layer will be described. The rubber-based adhesive contains a rubber component and a tackifier resin, and it is preferable to use a styrene-isoprene block copolymer as the rubber component. The styrene-isoprene block copolymer has a diblock ratio of preferably 25 to 70% by mass, more preferably 30 to 65% by mass, and even more preferably 45 to 60% by weight. Here, the diblock refers to a diblock consisting of styrene and isoprene. By setting the diblock ratio within the above range, it becomes easier to increase the adhesive strength. In addition to the diblock, the styrene-isoprene block copolymer also contains one having three or more blocks, such as a triblock consisting of a styrene, isoprene, and styrene block.

The amount of styrene in the styrene-isoprene block copolymer is not particularly limited, but is preferably 14 to 24% by mass, and more preferably 15 to 18% by mass. If the amount of styrene is 14% by mass or more, the adhesive tends to have high cohesiveness. If the amount of styrene is 24% by mass or less, the cohesive strength becomes moderate and adhesive strength is easily expressed.
The molecular weight of the styrene-isoprene block copolymer is not particularly limited, but is preferably a mass average molecular weight of 100,000 to 400,000, and more preferably 150,000 to 250,000. The mass average molecular weight referred to here is a molecular weight measured in terms of polystyrene by a GPC (gel permeation chromatography) method.

The tackifier resin used in the rubber-based adhesive can be any of various types, but is preferably a petroleum-based resin, a terpene resin, or a coumarone resin. The tackifier resin may be used alone or in combination of two or more types, but it is preferable to use a petroleum-based resin in combination with at least one selected from a terpene resin and a coumarone resin. Such a combination of tackifier resins makes it easier to improve the adhesive strength.
Examples of the petroleum resin include aliphatic petroleum resin (C5 petroleum resin), alicyclic petroleum resin, aromatic petroleum resin, etc., and from the viewpoint of compatibility with the styrene-isoprene block copolymer, aliphatic petroleum resin is preferred. In addition, it is preferable to use a petroleum resin having a softening point of about 90 to 120°C.
The terpene resin to be used has a softening point of about 80 to 120° C., but from the viewpoint of ensuring adhesive strength, it is preferable that the softening point is less than 100° C. The coumarone resin to be used has a softening point of preferably 110 to 130° C., more preferably 115 to 125° C., in order to ensure cohesive strength.

The amount of the tackifier resin is preferably 60 to 250 parts by mass, more preferably 100 to 200 parts by mass, and even more preferably 110 to 180 parts by mass, per 100 parts by mass of the rubber component. By setting the amount of the tackifier resin within the above range, it is possible to improve the cohesive force and impart appropriate adhesive strength.
In addition, when a petroleum-based resin is used in combination with at least one selected from a terpene resin and a coumarone resin, the amount of the petroleum-based resin is preferably 50 to 200 parts by mass, more preferably 60 to 150 parts by mass, and more preferably 60 to 110 parts by mass, per 100 parts by mass of the rubber component. On the other hand, the amount of the terpene resin is preferably 10 to 70 parts by mass, more preferably 20 to 60 parts by mass, and even more preferably 30 to 50 parts by mass, per 100 parts by mass of the rubber component. Furthermore, the amount of the coumarone resin is preferably 10 to 60 parts by mass, more preferably 15 to 50 parts by mass, and even more preferably 20 to 40 parts by mass, per 100 parts by mass of the rubber component.
The rubber-based adhesive may contain the above-mentioned fine particles, like the acrylic-based adhesive, and may also contain a softener, an antioxidant, a filler, etc., as necessary.

(Urethane adhesive)
The urethane-based adhesive is not particularly limited, and examples thereof include urethane resins obtained by reacting at least a polyol with a polyisocyanate compound. Examples of the polyol include polyether polyol, polyester polyol, polycarbonate polyol, polycaprolactone polyol, etc. Examples of the polyisocyanate compound include diphenylmethane diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, etc. These urethane adhesives may be used alone or in combination of two or more.
In addition, as the urethane-based adhesive, a urethane resin obtained by reacting a polyurethane polyol with a polyfunctional isocyanate-based curing agent may be used. The polyurethane polyol may be a reaction product of the above-mentioned polyol with a polyisocyanate compound, or a reaction product of a polyol with a polyisocyanate compound and a chain extender such as a diamine. As the polyfunctional isocyanate-based curing agent, any compound having two or more isocyanate groups may be used, and the above-mentioned isocyanate compounds may be used.
The urethane-based adhesive may contain the above-mentioned fine particles in addition to the urethane resin, and may also contain a tackifier resin, a softener, an antioxidant, a filler, etc., as necessary.

(Silicone adhesive)
Examples of silicone-based adhesives include silicone-based adhesives of addition reaction type, peroxide curing type, or condensation reaction type. Among them, addition reaction type silicone-based adhesives are preferably used from the viewpoint of being curable at low temperature in a short time. The addition reaction type silicone-based adhesive is cured when the adhesive layer is formed. When an addition reaction type silicone-based adhesive is used as the silicone-based adhesive, the silicone-based adhesive may contain a catalyst such as a platinum catalyst.
The silicone-based adhesive may contain fine particles, and may also contain a crosslinking agent and various additives for controlling adhesive strength.

(Carbon dioxide fixation agent)
The adhesive layer preferably contains one or more kinds of carbon dioxide fixatives. This makes it easier for the carbon dioxide fixation surface coating material of the present invention to absorb and fix carbon dioxide in the atmosphere. Examples of carbon dioxide fixatives include amines such as monoethanolamine, methyldiethanolamine, 2-amino-2-methyl-1-propanol, piperazine, and polyethyleneimine; hydroxides of alkaline earth metals such as magnesium hydroxide, calcium hydroxide, strontium hydroxide, and barium hydroxide; oxides of alkaline earth metals such as magnesium oxide and calcium oxide; hydroxides of alkali metals such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; aluminosilicates such as zeolite; mesoporous silica; and silica gel. These carbon dioxide fixatives can be used alone or in combination of two or more. Among these carbon dioxide fixatives, basic compounds are preferred, hydroxides of alkaline earth metals are preferred, and calcium hydroxide is more preferred. Calcium hydroxide is preferably contained in the form of particles dispersed in the adhesive layer. In the present invention, by using calcium hydroxide, the photocuring property of the pressure-sensitive adhesive composition is less likely to be inhibited, and the deterioration of the adhesive performance of the pressure-sensitive adhesive layer caused by the carbon dioxide fixing agent can also be suppressed.
In addition, calcium hydroxide reacts with carbon dioxide in the air to become calcium carbonate, and the calcium carbonate thus produced is retained in the carbon dioxide fixing surface coating material. In the present invention, by using calcium hydroxide, carbon dioxide can be efficiently fixed in the adhesive layer.

The content of the carbon dioxide fixative is preferably 5 parts by mass or more per 100 parts by mass of the total content of the adhesive components excluding the carbon dioxide fixative from all the components constituting the adhesive layer. When the content of the carbon dioxide fixative is 5 parts by mass or more, the carbon dioxide absorbing ability of the carbon dioxide fixative surface coating material can be sufficiently increased. From this viewpoint, the content of the carbon dioxide fixative is more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, per 100 parts by mass of the total content of the adhesive components excluding the carbon dioxide fixative. Furthermore, the content of the carbon dioxide fixative is preferably 80 parts by mass or less, per 100 parts by mass of the total content of the adhesive components excluding the carbon dioxide fixative. When the content of the carbon dioxide fixative is 80 parts by mass or less, it is possible to prevent the adhesive strength of the adhesive layer from being reduced or the photocuring property from being suppressed by the carbon dioxide fixative. From this viewpoint, the content of the carbon dioxide fixative is more preferably 70 parts by mass or less, and even more preferably 60 parts by mass or less, per 100 parts by mass of the total content of the adhesive components excluding the carbon dioxide fixative.

(Thickness)
The thickness of the adhesive layer is preferably 100 μm or more. By making the thickness 100 μm or more, the adhesive strength of the carbon dioxide fixing surface coating material can be further improved. From this viewpoint, the thickness of the adhesive layer is more preferably 250 μm or more, even more preferably 300 μm or more, and even more preferably 500 μm or more. In addition, the upper limit of the thickness of the adhesive layer is not particularly limited, but from the viewpoint of the decrease in workability due to the increase in weight while obtaining the effect of improving the adhesive strength of the carbon dioxide fixing surface coating material according to the thickness, it is, for example, 2000 μm, and 1200 μm is preferable.

(90 degree peel adhesive strength)
The 90-degree peel adhesive strength of the adhesive layer to mortar is preferably 5 N/15 mm or more. By having a 90-degree peel adhesive strength of 5 N/15 mm or more, the adhesiveness to adherends such as civil engineering structures and architectural structures is further improved. From this viewpoint, the 90-degree peel adhesive strength of the adhesive layer is more preferably 10 N/15 mm or more, even more preferably 12 N/15 mm or more, and even more preferably 20 N/15 mm or more. The higher the 90-degree peel adhesive strength of the adhesive layer, the better, but it is usually 100 N/15 mm or less. The 90-degree peel adhesive strength of the adhesive layer can be measured by the method described in the examples below. The 90-degree peel adhesive strength of the adhesive layer can be adjusted to a desired range by adjusting the composition of the adhesive.

(Storage Modulus)
The storage modulus of the pressure-sensitive adhesive layer at a temperature of 23° C. is preferably 50,000 to 1,000,000 Pa. When the storage modulus at a temperature of 23° C. is within the above range, the adhesive strength of the pressure-sensitive adhesive tape is increased, and the protective performance of the pressure-sensitive adhesive tape against the adherend is easily improved. From this viewpoint, the storage modulus of the pressure-sensitive adhesive layer at a temperature of 23° C. is more preferably 100,000 to 800,000 Pa, and further preferably 200,000 to 700,000 Pa. The storage modulus of the pressure-sensitive adhesive layer at a temperature of 23° C. can be measured by the method described in the Examples below. The storage modulus of the pressure-sensitive adhesive layer at a temperature of 23° C. can be adjusted by the composition of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer.

(Method for producing pressure-sensitive adhesive layer)
Hereinafter, a case will be described in which the adhesive constituting the adhesive layer is formed from a photocurable acrylic adhesive, but a known method can also be used to manufacture the adhesive layer from other adhesives.
The acrylic adhesive forming the adhesive layer can be obtained by irradiating a photocurable adhesive composition containing the above-mentioned polymerizable monomer with light to polymerize the polymerizable monomer. Here, the adhesive composition may contain a carbon dioxide fixing agent, and if necessary, at least one of a tackifier resin, fine particles, and other components.
More specifically, first, a polymerizable monomer, a carbon dioxide fixing agent, and optionally a tackifier resin, fine particles, and other components are charged into a reaction vessel such as a glass vessel and mixed to obtain a pressure-sensitive adhesive composition.
Next, in order to remove dissolved oxygen in the pressure-sensitive adhesive composition, an inert gas such as nitrogen gas is generally supplied to purge the oxygen. Then, the pressure-sensitive adhesive composition is applied onto a release sheet, or onto a substrate such as a resin film, woven fabric, or nonwoven fabric, and then irradiated with light to polymerize the polymerizable monomer, thereby obtaining a pressure-sensitive adhesive layer.
The steps from coating or impregnation with the pressure-sensitive adhesive composition to the step of irradiating with light are preferably carried out in an inert gas atmosphere or in a state in which oxygen is blocked by a film or the like.
In the present production method, the pressure-sensitive adhesive composition obtained by mixing the components may be pre-polymerized before being applied to a release sheet, a substrate, or the like, in order to increase the viscosity.

(Base material)
The carbon dioxide fixation surface covering material of the present invention may further include a substrate. When the substrate is provided, the adhesive layer is preferably provided on at least one side of the substrate. The substrate in the carbon dioxide fixation surface covering material of the present invention is not particularly limited, but examples thereof include sheet-like materials such as resin films, nonwoven fabrics, and metal foils.
Examples of the resin film include acrylic films, polyester films such as PET (polyethylene terephthalate) films, fluororesin films, polyvinyl chloride films, AES resin films, and ASA resin films.
The nonwoven fabric is made of synthetic resin fibers, such as polyamide, polyester, polyacrylic, polyolefin, or polyurethane.
Examples of metal foils include metal foils of iron and its alloys, metal foils of metals having a lower electric potential than iron, such as chromium, zinc, titanium, aluminum, and magnesium, and metal foils of metals having a higher electric potential than iron, such as gold, silver, copper, tin, nickel, and cobalt.
These sheet-like materials can be used alone or in combination of two or more. From the viewpoint of protecting the pressure-sensitive adhesive layer, the substrate is preferably a resin film, more preferably an acrylic film, a PET film, or a fluororesin film, and further preferably an acrylic film.
In addition, in the case of a resin film, the interfacial strength can be easily increased by modifying the surface of the substrate by corona treatment or by providing an undercoat layer.

The thickness of the substrate is not particularly limited, but is preferably 10 to 500 μm, more preferably 30 to 400 μm, and even more preferably 40 to 300 μm. When the substrate is 10 μm or more thick, it can function as a support. Furthermore, when the substrate is 500 μm or less thick, it becomes easier to improve adhesion to civil engineering structures and architectural structures.

The surface of the substrate facing the adhesive layer may be surface-modified by corona treatment. This can further increase the interfacial strength between the substrate and the adhesive layer in the carbon dioxide fixing surface coating material.

(Total light transmittance)
The total light transmittance of the carbon dioxide fixing surface covering material having a substrate is preferably 30% or more. When the total light transmittance of the carbon dioxide fixing surface covering material having a substrate is 30% or more, the adherend can be visually recognized through the carbon dioxide fixing surface covering material. From this viewpoint, the total light transmittance of the carbon dioxide fixing surface covering material having a substrate is more preferably 40% or more, even more preferably 50% or more, and even more preferably 60% or more. The upper limit of the range of the total light transmittance of the carbon dioxide fixing surface covering material having a substrate is not particularly limited, but is usually 100% or less. The total light transmittance of the carbon dioxide fixing surface covering material having a substrate may be measured in accordance with JIS K 7361 by laminating a specified release PET to the surface of the carbon dioxide fixing surface covering material opposite to the surface on which the substrate is provided. Specifically, the total light transmittance of the carbon dioxide fixing surface covering material having a substrate can be measured by the method described in the Examples described later. It can be adjusted by the composition of the adhesive constituting the adhesive layer, the thickness of the adhesive layer, the composition of the substrate, the thickness of the substrate, and the like.

(Undercoat layer)
The carbon dioxide fixing surface coating material of the present invention preferably further comprises an undercoat layer on the surface of the substrate on the side of the adhesive layer. This can further improve the interfacial strength between the substrate and the adhesive layer. The undercoat can be formed by applying an undercoat paint to the substrate and drying it as necessary.

(Coating film)
The carbon dioxide fixing surface covering material of the present invention preferably further comprises a coating film provided on the surface of the substrate opposite to the surface on the pressure-sensitive adhesive layer side. This can further improve the weather resistance of the carbon dioxide fixing surface covering material of the present invention. The coating film can be formed by applying a paint to the substrate and drying it as necessary.

ここで、Ｐは標準気圧（１０１３２５Ｐａ）であり、Ｖｄはデシケーターの容積（７Ｌ）であり、Ｒは気体定数（８３１０Ｐａ・Ｌ／（Ｋ・ｍｏｌ））であり、Ｔは測定温度（２９６Ｋ）であり、ΔＤは２４時間経過後のデシケーター内のＣＯ_２濃度とデシケーター内のＣＯ_２濃度の初期濃度との間の差の濃度（ｖｏｌ％）であり、Ｖｓはデシケーターに入れた二酸化炭素固定表面被覆材の体積（ｍ^３）である。
　なお、二酸化炭素固定表面被覆材が基材を備える場合は、二酸化炭素固定表面被覆材の基材がデシケーターの内面やＣＯ_２濃度計に触れないように、ＳＵＳ板に貼った状態の二酸化炭素固定表面被覆材とＣＯ_２濃度計をデシケーターに入る。 When the carbon dioxide absorption amount of the carbon dioxide fixing surface coating material of the present invention is measured by the carbon dioxide absorption amount measurement method described below, the carbon dioxide absorption amount per unit volume of the carbon dioxide fixing surface coating material of the present invention 24 hours after the start of the measurement is preferably 3 kg/ ^m3 or more.
<Method for measuring carbon dioxide absorption>
In a 23°C environment, the carbon dioxide fixing surface coating material attached to a SUS plate and the CO ₂ concentration meter are placed in the desiccator so that the carbon dioxide fixing surface coating material does not touch the inner surface of the desiccator or the CO ₂ concentration meter, and the desiccator is evacuated to -0.040 MPa (gauge pressure). Then, the carbon dioxide gas cylinder and the desiccator are connected, and CO ₂ (component concentration 99.5 vol% or more) is injected into the desiccator until the internal pressure of the desiccator becomes 0.000 MPa (gauge pressure). In a 23°C environment, the CO ₂ concentration measured by the CO ₂ concentration meter in the desiccator 10 minutes after the start of injection is set as the initial concentration, and in a 23°C environment, the CO ₂ concentration in the desiccator 24 hours after the initial concentration measurement is measured by the CO ₂ concentration meter, and the carbon dioxide absorption amount per unit volume of the carbon dioxide fixing surface coating material is calculated using the following formula (1). As a _CO2 concentration meter, for example, a product name "High Concentration Combustible Gas Detector XP-3140" manufactured by Shin Cosmos Electric Co., Ltd. may be used.

Here, P is standard atmospheric pressure (101,325 Pa), Vd is the volume of the desiccator (7 L), R is the gas constant (8,310 Pa·L/(K·mol)), T is the measurement temperature (296 K), ΔD is the difference in concentration (vol%) between the _CO2 concentration in the desiccator after 24 hours and the initial _CO2 concentration in the desiccator, and Vs is the volume ( ^m3 ) of the carbon dioxide fixing surface coating material placed in the desiccator.
In addition, if the carbon dioxide fixing surface coating material has a base material, the carbon dioxide fixing surface coating material attached to a SUS plate and the _CO2 concentration meter are placed in the desiccator so that the base material of the carbon dioxide fixing surface coating material does not come into contact with the inner surface of the desiccator or the _CO2 concentration meter.

When the carbon dioxide absorption amount per unit volume of the carbon dioxide fixing surface coating material is 3 kg/ ^m3 or more, the carbon dioxide fixing surface coating material has sufficient carbon dioxide absorption capacity. From this viewpoint, the carbon dioxide absorption amount per unit volume of the carbon dioxide fixing surface coating material of the present invention is more preferably 10 kg/ ^m3 or more, and even more preferably 18 kg/ ^m3 or more. The higher the carbon dioxide absorption amount per unit volume of the carbon dioxide fixing surface coating material, the more preferable it is, but the upper limit is, for example, 500 kg/ ^m3 . The carbon dioxide absorption amount per unit volume of the carbon dioxide fixing surface coating material can be adjusted by the type and content of the carbon dioxide fixing agent contained in the carbon dioxide fixing surface coating material.

(Civil Engineering Structures and Architectural Structures)
The civil engineering structure or architectural structure to which the carbon dioxide fixation surface coating material of the present invention is attached is preferably either a concrete structure or a steel structure. The carbon dioxide fixation surface coating material can be attached to either a concrete structure or a steel structure to adequately protect the civil engineering structure or the architectural structure.
The concrete structures and steel structures refer to various structures that use concrete, reinforcing bars, steel frames, tension steel, etc., such as railway and road bridges, tunnels, chimneys, and buildings, and the specific targets are not particularly limited.

(Configuration of carbon dioxide fixing surface coating material)
The carbon dioxide fixing surface covering material may be composed of only an adhesive layer. Alternatively, as shown in Fig. 1, the carbon dioxide fixing surface covering material 10 may be a single-sided adhesive tape having a substrate 12 and an adhesive layer 11 provided on one side of the substrate 12. This allows the adhesive layer 11 to be protected by the substrate 12.
The carbon dioxide fixing surface covering material in each drawing is used by being attached to a civil engineering structure or an architectural structure with the surface 11A of the adhesive layer 11 as an adhesive surface.

When the carbon dioxide fixing surface coating material consists only of an adhesive layer, the carbon dioxide fixing surface coating material becomes a double-sided adhesive tape. However, as shown in FIG. 2, even when the carbon dioxide fixing surface coating material has a substrate 12, adhesive layers 11 may be provided on both sides of the substrate 12, so that the carbon dioxide fixing surface coating material 10 becomes a double-sided adhesive tape.

Furthermore, before the carbon dioxide fixing surface covering material 10 is attached to an adherend (civil engineering structure or architectural structure), a release sheet (not shown) may be attached to the surface of the adhesive layer 11, which is the bonding surface with the adherend. The release sheet may be peeled off before the material is attached to the adherend. By providing the release sheet, the bonding surface of the carbon dioxide fixing surface covering material 10 is appropriately protected. The release sheet may consist of a resin film alone, or may be a resin film with one side subjected to a release treatment, or may be release paper, etc.

(Method of using the carbon dioxide fixing surface coating material of the present invention)
The carbon dioxide fixing surface coating material of the present invention may be directly attached to a civil engineering structure or architectural structure. However, it is preferable to coat the surface of the civil engineering structure or architectural structure with a primer paint, and then, while the primer paint applied to the civil engineering structure or architectural structure is still wet, to attach the carbon dioxide fixing surface coating material of the present invention onto the primer layer formed from the primer paint.

The primer coating preferably contains an epoxy resin. Epoxy resins have excellent adhesion to concrete structures, and therefore can provide high-level concrete spalling prevention performance. Here, the epoxy resin is preferably a resin having at least two epoxy groups in one molecule, and is obtained, for example, by reacting a polyhydric alcohol or a polyhydric phenol with a halohydrin. Specific examples include bisphenol A type epoxy resin, halogenated bisphenol A type epoxy resin, novolac type epoxy resin, polyglycol type epoxy resin, bisphenol F type epoxy resin, epoxidized oil, 1,6-hexanediol diglycidyl ether, and neopentyl glycol diglycidyl ether, as well as modified epoxy resins such as amine-modified epoxy resin, isocyanate-modified epoxy resin, acrylic-modified epoxy resin, urethane-modified epoxy resin, and polyester-modified epoxy resin, which are modified products of such epoxy resins. These epoxy resins may be used alone or in combination of two or more.

The above primer paint may contain other components, such as other resins, hardeners, pigments, thickeners, rust inhibitors, dispersants, defoamers, leveling agents, anti-settling agents, anti-sagging agents, hardening accelerators, anti-algae agents, anti-mold agents, preservatives, ultraviolet absorbers, and light stabilizers, as needed.

The means for applying the primer coating is not particularly limited, and known applying means such as brush application, roller application, trowel application, spatula application, flow coater application, spray application (e.g. aerosol spray application, air spray application, airless spray application, etc.) can be used.

[Surface coating method for civil engineering and architectural structures]
The surface coating method for civil engineering structures and architectural structures of the present invention includes a step of attaching the carbon dioxide fixing surface coating material of the present invention to the surface of the civil engineering structure or architectural structure. This makes it more efficient to enable the civil engineering structure or architectural structure to absorb and fix carbon dioxide in the atmosphere. Note that the carbon dioxide fixing surface coating material, civil engineering structure, and architectural structure of the present invention have already been explained in the section on the carbon dioxide fixing surface coating material, so explanations of the carbon dioxide fixing surface coating material, civil engineering structure, and architectural structure of the present invention will be omitted.

Another surface coating method for civil engineering structures and architectural structures of the present invention includes a step of attaching the carbon dioxide fixing surface coating material of the present invention, which is made of an adhesive layer, to the surface of the civil engineering structure or architectural structure, and a step of attaching a substrate to the surface of the civil engineering structure or architectural structure opposite to the surface side of the carbon dioxide fixing surface coating material attached to the civil engineering structure or architectural structure. This makes it efficient to work so that the civil engineering structure or architectural structure can absorb and fix carbon dioxide in the atmosphere. Note that the carbon dioxide fixing surface coating material, adhesive layer, substrate, civil engineering structure, and architectural structure of the present invention have already been explained in the section on the carbon dioxide fixing surface coating material, so the explanation of the carbon dioxide fixing surface coating material, adhesive layer, substrate, civil engineering structure, and architectural structure of the present invention will be omitted. However, according to this method, the substrate can be easily changed depending on the type of adherend and the purpose, and for example, a substrate having design properties may be used for decoration of the civil engineering structure and architectural structure.
In addition, in this method, an example has been described in which the carbon dioxide fixing surface covering material is made of a single adhesive layer. However, any carbon dioxide fixing surface covering material may be used as long as a substrate can be attached to the surface opposite to the surface of the carbon dioxide fixing surface covering material attached to the civil engineering structure or architectural structure, and for example, a double-sided adhesive tape having adhesive layers on both sides of the substrate may be used.

[Civil engineering structures and architectural structures]
The civil engineering structure of the present invention has the carbon dioxide fixing surface covering material of the present invention attached thereto, and the architectural structure of the present invention has the carbon dioxide fixing surface covering material of the present invention attached thereto. Note that since the carbon dioxide fixing surface covering material, civil engineering structure, and architectural structure of the present invention have already been explained in the section on the carbon dioxide fixing surface covering material, explanation of the carbon dioxide fixing surface covering material, civil engineering structure, and architectural structure of the present invention will be omitted.

The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples.

[Evaluation method]

ここで、Ｐは標準気圧（１０１３２５Ｐａ）であり、Ｖｄはデシケーターの容積（７Ｌ）であり、Ｒは気体定数（８３１０Ｐａ・Ｌ／（Ｋ・ｍｏｌ））であり、Ｔは測定温度（２９６Ｋ）であり、ΔＤは２４時間経過後のデシケーター内のＣＯ_２濃度とデシケーター内のＣＯ_２濃度の初期濃度との間の差の濃度（ｖｏｌ％）であり、Ｖｓはデシケーターに入れた二酸化炭素固定表面被覆材の体積（ｍ^３）である。
＜評価基準＞
　Ａ：１８ｋｇ／ｍ^３以上
　Ｂ：３ｋｇ／ｍ^３以上
　Ｃ：３ｋｇ／ｍ^３未満 In the examples and comparative examples, the carbon dioxide fixing surface coating materials were evaluated by the following evaluation methods.
(Method for measuring carbon dioxide absorption)
The carbon dioxide fixing surface coating material attached to the SUS plate and a _CO2 concentration meter (manufactured by New Cosmos Electric Co., Ltd., product name "High concentration combustible gas detector XP-3140") were placed in a desiccator, and the desiccator was evacuated to -0.040 MPa (gauge pressure). At this time, the carbon dioxide fixing surface coating material was placed so that it did not touch the inner surface of the desiccator or the _CO2 concentration meter. Furthermore, when the carbon dioxide fixing surface coating material had a base material, it was placed so that the base material surface of the carbon dioxide fixing surface coating material did not touch the inner surface of the desiccator or the _CO2 concentration meter. After that, a carbon dioxide gas cylinder was connected to the desiccator, and _CO2 (component concentration 99.5 vol% or more) was injected into the desiccator until the internal pressure of the desiccator reached 0.000 MPa (gauge pressure). The _CO2 concentration measured with a _CO2 meter in the desiccator 10 minutes after the start of injection was taken as the initial concentration, and the _CO2 concentration in the desiccator 24 hours after the initial concentration measurement was measured with a _CO2 meter, and the amount of carbon dioxide absorbed per unit volume of the carbon dioxide fixing surface coating material was calculated using the following formula (1). The evaluation was performed in a 23°C environment.

Here, P is standard atmospheric pressure (101,325 Pa), Vd is the volume of the desiccator (7 L), R is the gas constant (8,310 Pa·L/(K·mol)), T is the measurement temperature (296 K), ΔD is the difference in concentration (vol%) between the _CO2 concentration in the desiccator after 24 hours and the initial _CO2 concentration in the desiccator, and Vs is the volume ( ^m3 ) of the carbon dioxide fixing surface coating material placed in the desiccator.
<Evaluation criteria>
A: 18kg/m ³ or more B: 3kg/m ³ or more C: Less than 3kg/m ³

(90 degree peel adhesion of adhesive layer)
A film was laminated on the adhesive used in the adhesive layer of the carbon dioxide fixing surface coating material to prepare a measurement adhesive sheet having a film and an adhesive layer on one side of the film. The film may be a film that is difficult to stretch so that it is not broken at the interface between the film and the glue during the adhesive force measurement. In this measurement, a primer-treated PET film was used. The obtained measurement adhesive sheet was cut to a width of 15 mm and a length of 100 mm to prepare a measurement sample. The measurement sample was attached to the following standard mortar plate through the adhesive layer in an environment of 23°C and 50 RH%, and cured for 3 days in an environment of 23°C and 50 RH%. In addition, when attaching to the mortar, a 2 kg roller was made to reciprocate twice at a speed of 10 ± 0.5 mm / s. Then, the measurement sample that had been cured for 3 days was fixed to the chuck of a tensile tester (manufactured by A & D Co., Ltd., product name "Tensilon universal material testing machine"). Thereafter, in an environment of 23°C and 50% RH, the adhesive sheet was pulled for 60 mm or more at a peel angle of 90° and a speed of 300 mm/min, and the average value of the load (N) detected by the load cell was recorded and used as the 90° peel adhesive strength.
(Standard mortar board)
The standard mortar plates were prepared as follows.
A mortar board (compliant with JIS R 5201, width 70 mm, length 150 mm) was prepared. Dust attached to the surface of the prepared mortar board was removed using masking tape. At this time, an OPP tape (manufactured by Sekisui Chemical Co., Ltd., product name "Tough Light Tape No. 835") was attached to the surface of the mortar board, the OPP tape was peeled off from the surface of the mortar board, and the OPP tape was attached to the release surface of a release PET (polyethylene terephthalate) film (thickness 50 μm) to prepare a sample, and dust was removed until the total light transmittance reached 87%. The mortar board from which dust had been removed as described above was used as a reference mortar board, and the 90-degree peel adhesion of the adhesive layer to the reference mortar board was measured.

(Storage Modulus of Pressure-Sensitive Adhesive Layer)
The storage modulus of the pressure-sensitive adhesive layer was calculated by measuring the dynamic viscoelasticity spectrum using a DVA-200 (manufactured by IT Measurement & Control Co., Ltd.) under the conditions of shear mode: 10 Hz, strain: 0.1%, temperature range: -50°C to 200°C, and heating rate: 6°C/min.

(Total light transmittance of carbon dioxide fixing surface coating material with substrate)
A release PET film (polyethylene terephthalate film: manufactured by Lintec Corporation, product name "PET5002") was laminated onto the adhesive layer of the carbon dioxide fixing surface covering material equipped with a substrate. Thereafter, the total light transmittance of the carbon dioxide fixing surface covering material laminated with the release PET was measured in accordance with JIS K 7361 using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "Haze Meter NDH4000") in an atmosphere of 23°C and humidity of 50%.

[Examples 1, 3, 5, 7, 9, 11, and Comparative Example 1]
According to the formulations shown in Tables 1 and 2, pressure-sensitive adhesive compositions were prepared. The pressure-sensitive adhesive compositions were purged with nitrogen to remove dissolved oxygen. The pressure-sensitive adhesive compositions were then applied onto a release-treated PET film, which was then covered with another release-treated PET film. In this state, the lamp intensity of the chemical lamp was adjusted so that the ultraviolet irradiation intensity was 0.5 mW/ ^cm2 , and the pressure-sensitive adhesive compositions were irradiated with ultraviolet light for 5 minutes to cure.
By the above procedure, a carbon dioxide fixing surface covering material consisting of a single pressure-sensitive adhesive layer was obtained. The results are shown in Tables 1 and 2. The carbon dioxide fixing surface covering material was peeled off from the PET film and evaluated.

[Examples 2, 4, 6, 8, 10, 12 to 15, Comparative Example 2]
According to the formulations shown in Tables 1 and 2, pressure-sensitive adhesive compositions were prepared. The pressure-sensitive adhesive compositions were purged with nitrogen to remove dissolved oxygen. The pressure-sensitive adhesive compositions were then applied onto a release-treated PET film, which was then covered with another release-treated PET film. In this state, the lamp intensity of the chemical lamp was adjusted so that the ultraviolet irradiation intensity was 0.5 mW/ ^cm2 , and the pressure-sensitive adhesive compositions were irradiated with ultraviolet light for 5 minutes to cure.
Next, one side of the release-treated PET film was peeled off, and the substrates shown in Tables 1 and 2 were laminated onto the adhesive surface.
By the above procedure, a carbon dioxide fixing surface coating material consisting of a substrate and a pressure-sensitive adhesive layer was obtained. The carbon dioxide fixing surface coating material was also peeled off from the other PET film and evaluated. The results are shown in Tables 1 and 2.

The components in Tables 1 and 2 are as follows.
Olefin polymer: product name "L-1253", manufactured by Kuraray Co., Ltd., hydrogenated polybutadiene having a (meth)acryloyl group at one end Tackifying resin 1: product name "Arcon P140", manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 140°C
Tackifier resin 2: Product name "Alcon P100", manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 100°C
Crosslinking agent: NK Ester A-HD-N, bifunctional alkyl acrylate, manufactured by Shin-Nakamura Chemical Co., Ltd. Polymerization initiator: 2,2-dimethoxy-2-phenylacetophenone Acrylic film 1: Product name "Soft acrylic sheet", manufactured by Tatsuta Chemical Co., Ltd.
Acrylic film 2: Mitsubishi Chemical Corporation, product name "ACRYPLEN™ MTXA45"
Carbon dioxide fixation agent: Calcium hydroxide, Kanto Chemical Co., Ltd., product number 07069-00

By comparing the carbon dioxide fixing surface coating materials of Examples 1 to 15 and the carbon dioxide fixing surface coating materials of Comparative Examples 1 and 2, it was found that the carbon dioxide fixing surface coating materials can absorb and fix carbon dioxide in the atmosphere because the adhesive layer contains a carbon dioxide fixing agent. In addition, from the carbon dioxide fixing surface coating materials of Examples 2, 4, 6, 8, 10, and 12 to 15, it was found that even if the carbon dioxide fixing surface coating materials have a base material, they can absorb and fix carbon dioxide in the atmosphere.

10 Carbon dioxide fixing surface coating material 11 Adhesive layer 12 Base material

Claims (14)

A carbon dioxide fixing surface coating material that has an adhesive layer and is attached to the surface of a civil engineering or architectural structure to absorb and fix carbon dioxide in the air. The carbon dioxide fixing surface coating material according to claim 1, wherein when the carbon dioxide absorption amount of the carbon dioxide fixing surface coating material is measured by the carbon dioxide absorption amount measurement method described below, the carbon dioxide absorption amount per unit volume of the carbon dioxide fixing surface coating material is 3 kg/ ^m3 or more 24 hours after the start of measurement.
<Method for measuring carbon dioxide absorption>
In a 23°C environment, the carbon dioxide fixing surface coating material attached to a SUS plate and the _CO2 concentration meter are placed in a desiccator so that the carbon dioxide fixing surface coating material does not come into contact with the inner surface of the desiccator or the _CO2 concentration meter. The desiccator is then evacuated to -0.040 MPa, a carbon dioxide gas cylinder is connected to the desiccator, and _CO2 is injected into the desiccator until the internal pressure of the desiccator reaches 0.000 MPa. The _CO2 concentration measured with the _CO2 concentration meter in the desiccator 10 minutes after the start of injection is defined as the initial concentration, and the _CO2 concentration in the desiccator 24 hours after the initial concentration measurement is measured with the _CO2 concentration meter. The amount of carbon dioxide absorbed per unit volume of the carbon dioxide fixing surface coating material is calculated using the following formula (1):

Here, P is standard atmospheric pressure (101,325 Pa), Vd is the volume of the desiccator (7 L), R is the gas constant (8,310 Pa·L/(K·mol)), T is the measurement temperature (296 K), ΔD is the difference in concentration (vol%) between the _CO2 concentration in the desiccator after 24 hours and the initial _CO2 concentration in the desiccator, and Vs is the volume ( ^m3 ) of the carbon dioxide fixing surface coating material placed in the desiccator. The carbon dioxide fixing surface coating material according to claim 1, wherein the adhesive layer contains one or more types of carbon dioxide fixing agents. The carbon dioxide fixing surface coating material according to claim 3, wherein the carbon dioxide fixing agent is a basic compound. The carbon dioxide fixing surface coating material according to claim 3, wherein the carbon dioxide fixing agent is an alkaline earth metal hydroxide. The carbon dioxide fixing surface coating material according to claim 3, wherein the carbon dioxide fixing agent is calcium hydroxide. The carbon dioxide fixing surface coating material according to claim 1, wherein the thickness of the adhesive layer is 100 μm or more. The carbon dioxide fixing surface coating material according to claim 1, wherein the adhesive layer is formed from a photocurable resin. The carbon dioxide fixing surface coating material according to claim 1, wherein the adhesive layer is formed from an acrylic adhesive. The carbon dioxide fixing surface coating material according to claim 1, further comprising a substrate. A surface coating method for civil engineering structures and architectural structures, comprising a step of attaching the carbon dioxide fixing surface coating material described in any one of claims 1 to 10 to the surface of the civil engineering structure or architectural structure. The surface coating method according to claim 11, further comprising a step of attaching a substrate to the surface of the civil engineering structure or the architectural structure opposite the surface side of the carbon dioxide fixing surface coating material attached to the civil engineering structure or the architectural structure. A civil engineering structure to which the carbon dioxide fixing surface coating material according to any one of claims 1 to 10 has been applied. An architectural structure to which the carbon dioxide fixing surface coating material according to any one of claims 1 to 10 has been applied.

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