JPH0586806B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a room-temperature-curing aqueous composition in which an isocyanate crosslinking agent captured by a polymer and a polymer crosslinked with this crosslinking agent are dispersed in water in the form of fine particles. It concerns how to use it. [Prior art] Conventionally, aqueous emulsion type compositions used as adhesives and paints are cured by crosslinking the main chain of the polymer by reacting with a crosslinking agent during the film formation process in order to increase film strength. It is being done. There are two types of such aqueous emulsion type compositions: those using a crosslinking agent that reacts at room temperature and those using a crosslinking agent that reacts at high temperatures. [Problems to be Solved by the Invention] In an aqueous emulsion type composition using a crosslinking agent that reacts at room temperature, if the polymer and the crosslinking agent are blended in advance, the crosslinking reaction will proceed during storage etc. and the aqueous emulsion type composition will It thickens and hardens, making it impossible to coat. Therefore, the polymer and crosslinking agent are kept separated in separate containers until used, and are mixed together each time they are used. However, it is cumbersome to mix the two liquids each time they are used. Moreover, if the compound is not used up within a certain period of time, the remaining amount will thicken and harden over time, which is inconvenient and uneconomical. In addition, in aqueous emulsion type compositions that use a latent crosslinking agent that reacts only at high temperatures, the crosslinking reaction does not occur at room temperature, and the polymer and crosslinking agent can be blended in advance, so the above-mentioned disadvantages do not occur. Since a heating device is required to cause the crosslinking reaction, it has the disadvantage that the heating device and the like are costly. The present invention was made in view of the above circumstances, and it is an object of the present invention to provide an aqueous room-temperature curable composition that uses a crosslinking agent that reacts at room temperature and that does not require separate holding of the polymer and the crosslinking agent, and a method for using the same. purpose. [Means for Solving the Problems] In order to achieve the above object, the present invention provides an aqueous room-temperature curable composition in which the following components (A) and (B) are dispersed in water in the form of fine particles. The first gist is (A) a hydrophobic solvent in which an isocyanate compound-trapping polymer (first polymer) is dispersed and stabilized by at least one of a block polymer and a graft polymer having two portions with different polarities. (B) A polymer having a functional group that reacts with an isocyanate group (second polymer). a hydrophobic solvent in which an isocyanate compound-trapping polymer (first polymer) is dispersed and stabilized by at least one of a block polymer and a graft polymer having two portions with different polarities;
a second having a functional group that reacts with an isocyanate group;
Prepare a room temperature curable aqueous composition in which the above polymers are dispersed in water in the form of fine particles, apply the room temperature curable aqueous composition to the surface to be treated, and volatilize the water and the hydrophobic solvent. The second gist is a method for using an aqueous room-temperature-curing composition in which a polymer film is formed by bringing the isocyanate compound-trapping polymer into contact with a polymer having a functional group that reacts with the isocyanate group. The present inventors have found that in an aqueous emulsion-type composition using a room-temperature-reactive crosslinking agent, the polymer and the crosslinking agent are separated and brought into contact after the composition is applied. We thought that the crosslinking reaction would not occur during storage even if the material was stored, and in order to realize this, we conducted a series of studies using various materials. As a result, an isocyanate compound was used as a crosslinking agent to capture it in the first polymer (this is referred to as O'), and this capture body was made hydrophobic using a block polymer (graft polymer) that has a dispersion stabilizing effect. By dispersing the isocyanate compound crosslinking agent in a solvent (denoted as O) and further dispersing this hydrophobic dispersion in the form of fine particles in water (denoted as W), the isocyanate compound crosslinking agent is isolated from water and O'/ An O/W type emulsion is prepared, and a polymer (second polymer) emulsion having a group that reacts with the isocyanate group of the isocyanate compound crosslinking agent is added to the O'/O/W emulsion.
When mixed with a type emulsion to form an aqueous emulsion type composition, the isocyanate compound crosslinking agent is in a trapped state in this composition, so no crosslinking reaction occurs during storage, etc., and after application of the emulsion type composition, It was discovered that the isocyanate compound crosslinking agent bleeds only when water or the like evaporates, and the second polymer is crosslinked to form a tough coating film, and the present invention was achieved based on this discovery. Next, the present invention will be explained in detail. A schematic diagram of the room temperature curable aqueous composition of the present invention is shown in FIG.
As shown in the figure. The room temperature curable aqueous composition of the present invention includes water 1, an isocyanate compound 2 which is a crosslinking agent, a first polymer 3 that captures this, and a first polymer 3.
consisting of a polymer 4 for dispersion stabilizing, a hydrophobic solvent 5, a second polymer 6 having a functional group that reacts with an isocyanate group in its molecular structure; A hydrophobic solvent 5 is emulsified and dispersed by surfactants 7 and 8. Note that auxiliary agents such as polymer modifiers may be added to the above composition as necessary. As is clear from FIG. 1, the isocyanate compound 2 is captured by the first polymer 3, and the captured polymer 3 has a polymer 4 having a dispersion stabilizing effect oriented around its outer periphery, and in this state, the hydrophobic solvent 5 The hydrophobic solvent 5 is further dispersed in the water 1 in the form of fine particles by the emulsifying and dispersing power of the surfactant 7. That is, the above-mentioned series of compounds are formed into a multilayer emulsion (hereinafter referred to as "O'/O/W Therefore, the isocyanate compound 2, which is a crosslinking agent, is captured in the first polymer 3, and the water 1 is captured by the liquid film of the hydrophobic solvent 5.
Because it is protected from water, it does not come into direct contact with water 1 and is in a stable state. On the other hand, the second polymer 6, which has a functional group that reacts with an isocyanate group in its molecular structure, is dispersed in water in the form of particles by the protective colloid and surfactant 8, and is also in a stable state. The isocyanate compound 2 is preferably a compound with low solubility in the hydrophobic solvent 5, such as hexamethylene diisocyanate (hereinafter abbreviated as "HMDI"), HMDI-water-biuret (manufactured by Asahi Kasei Corporation, Duranate 24A100), butanediol. Examples include HMDI adducts (manufactured by Asahi Kasei Co., Ltd., Dulanate EXP.D-101). Such isocyanate compound 2 has high polarity and is hardly soluble in hydrophobic solvents, and is weakly bonded to the polar portion of first polymer 3 that captures isocyanate compound 2 by van der Waals force. captured by etc. The first polymer 3 that captures the isocyanate compound 2 has an ethylenically unsaturated bond such as styrene, styrene derivative, butadiene, acrylonitrile, chloroprene, acrylic ester, methacrylic ester, vinyl acetate, ethylene, vinyl chloride, vinylidene chloride, etc. It consists of a single or copolymer of a monomer having the following. The hydrophobic solvent 5 for dispersing the first polymer 3 capturing the isocyanate compound 2 is as follows:
An isocyanate compound 2 having a low solubility is selected. That is, the isocyanate compound 2 is captured by the first polymer 3 in this hydrophobic solvent 5, and this capture is only realized when the isocyanate compound 2 is dispersed in the hydrophobic solvent 5 without being dissolved. This is because that. Also,
By using this type of solvent with low solubility, the dissolution and diffusion of isocyanate compound 2 is suppressed, and in the resulting composition, the reaction between isocyanate compound 2 and water 1 is suppressed, and isocyanate compound 2 is This prevents the occurrence of a phenomenon in which the second polymer 6 reacts with the isocyanate reactive group of the second polymer 6 during storage or the like, resulting in crosslinking and precipitation of the second polymer 6. Examples of this type of solvent include aliphatic hydrocarbons such as heptane, hexane, and cyclohexane. These solvents are appropriately selected in consideration of boiling point, isocyanate compound, polymerization stability, etc., but two or more types may be used in combination. At least one of a block polymer and a graft polymer is used as the polymer 4 that is oriented around the outer periphery of the first polymer 3 that captures the isocyanate compound 2 to stabilize its dispersion in the hydrophobic solvent 5. Examples of block polymers include, for example, SBS block polymers with a polystyrene-polybutadiene-polystyrene molecular structure, SIS block polymers with a polystyrene-polyisoprene-polystyrene molecular structure, or hydrogen atoms in the butadiene moiety of the above SBS block polymer. Examples include hydrogenated SBS block polymers with additives. In addition, as a graft polymer, for example, after dissolving natural rubber or depolymerized rubber such as those used in general hydrophobic emulsion production in an aliphatic hydrocarbon, a single substance or a mixture of polar monomers can be used. Examples include graft polymers obtained by polymerizing with an initiator such as benzoyl peroxide and grafting onto natural rubber or the like.
Such a polymer 4 has both a polar part and a non-polar part in the molecule, and is oriented around the outer periphery of the first polymer 3 with the polar part on the inside and the non-polar part on the outside. As mentioned above, since the non-polar part is on the outside and this part has an affinity with the hydrophobic solvent (non-polar) 5, it exerts a dispersion stabilizing effect. Further, the second polymer 6 having a functional group that reacts with an isocyanate group in its molecular structure reacts with a monomer that has a functional group that reacts with an isocyanate group and has an ethylenically unsaturated bond, and the isocyanate group. It is obtained by copolymerizing monomers that do not have functional groups and have ethylenically unsaturated bonds. Examples of the monomer having a functional group that reacts with the isocyanate group and having an ethylenically unsaturated bond include monomers having a hydroxyl group, a carboxyl group, an amino group, an epoxy group, etc. in the molecule. Here, the monomer having a hydroxyl group is, for example, allyl alcohol, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, monoallyl ether of polyhydric alcohol. , N-
Methylolated acrylamide, N-methylolmethacrylamide, etc., and monomers having a carboxyl group are, for example, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, crotonic acid, maleic acid monoester, itaconic acid monomer. ester,
It is an unsaturated polymerizable organic acid such as fumaric acid fragment and maleic acid. Further, monomers having an amino group include, for example, allylamine, tert-butylaminoethyl methacrylate, etc., and monomers having an epoxy group include, for example, glycidyl acrylate,
Glycidyl methacrylate, etc. In addition, monomers having an ethylenically unsaturated bond and not having a functional group that reacts with an isocyanate group include, for example, styrene, styrene derivatives, butadiene, acrylonitrile, methacrylonitrile, acrylic ester, and methacrylic acid. These include ester, vinyl acetate, ethylene, vinyl chloride, vinylidene chloride, etc. The second polymer 6 obtained by copolymerizing these monomers has a functional group in the molecule that reacts with the group, and therefore has the property of being crosslinked and cured when it comes into contact with an isocyanate compound. The surfactants 7 and 8 used in the present invention may be any of anionic surfactants, cationic surfactants, and nonionic surfactants, such as polyoxyethylene lauryl ether, polyoxyethylene nonyl phenyl ether, Examples include polyoxyethylene sorbitan monostearate. Additionally, water-soluble polymers such as starch, dextrin, methyl cellulose, carboxymethyl cellulose, polyacrylic acid or its water-soluble salt, polyacrylamide or its water-soluble copolymer, polyvinyl alcohol, water-soluble polyamide, etc. may be used. .
The above surfactants can be used alone or in combination of two or more. The room temperature curable aqueous composition of the present invention is produced using the above-mentioned raw materials, and the production is carried out, for example, as follows. First, make an O'/O/W type emulsion. That is, in a hydrophobic solvent in which an isocyanate compound such as HMDI and a coating polymer with a dispersion stabilizing effect such as SBS block polymer coexist, ethylenically unsaturated bonds prepared for forming an isocyanate compound-trapping polymer are mixed. By polymerizing or copolymerizing one or more monomers, a first polymer capturing an isocyanate compound is produced, and a first polymer dispersion in which the isocyanate compound is dispersed is obtained. In order to capture a large amount of the isocyanate compound in the first polymer, the polarity of the polymer is increased by copolymerizing a highly polar monomer such as acrylonitrile, methacrylonitrile, vinyl chloride, etc. It is sufficient to increase the affinity with large isocyanate compounds. The copolymerized amount of this polar monomer is preferably 0.1 to 50% of the total monomers, more preferably 1 to 30%. In addition, when producing the above-mentioned isocyanate compound-trapping polymer, it is also possible to copolymerize a monomer having a functional group that reacts with an isocyanate group, such as a hydroxyl group, a carboxyl group, or an amino group. In this case, the capture polymer is crosslinked with some of the isocyanate compounds. By varying the degree of crosslinking, the mobility of the polymer segments can be adjusted and, as a result, the rate of desorption can be controlled. However, if the copolymerization amount of a monomer having a functional group that reacts with an isocyanate group is too large, the isocyanate compound will promote crosslinking of the isocyanate compound-trapping polymer, and the movement of the polymer segment will be excessively suppressed. As a result, even if the captured isocyanate compound tries to act as a crosslinking agent for the final target polymer, it becomes difficult to release the isocyanate compound from the captured polymer, and it does not function smoothly. Therefore, it is desirable to limit the amount of copolymerized monomers that react with isocyanate groups to 10% or less of the total monomers. Also, double bonds such as divinylbenzene can be
Monomers having one or more monomers can also be used to control the rate of elimination of isocyanate compounds, but for the same reasons as above, the amount should be limited to 10% or less of the total monomers. The hydrophobic dispersion of the isocyanate compound-trapping polymer thus obtained is dispersed in the form of fine particles in water using a surfactant to prepare an O'/O/W type emulsion. Note that the stirring intensity for dispersion needs to be kept to an extent that does not destroy the dispersed state of the isocyanate compound-trapping polymer in the hydrophobic dispersion. In the above O'/O/W type emulsion, an isocyanate compound which is a crosslinking agent is captured, and this isocyanate compound capturing polymer is coated with a block or graft polymer which is a dispersion stabilizer and dispersed in a hydrophobic solvent in the form of particles. Furthermore, since this dispersion is stabilized with a surfactant and dispersed in particulate form in water, the isocyanate compound is isolated from the outside, and the second polymer undergoes a crosslinking reaction. Even if mixed in the same solution, the crosslinking reaction will not proceed. The O'/O/W type emulsion according to the present invention is stable and does not cause any separation phenomenon. Although the reason for this is not clear, it is assumed as follows. In other words, the O'/O/W interfacial film in the O'/O/W type emulsion is formed of at least one of a block polymer and a graft polymer, which are polymers, and is composed of an ordinary aggregation of monomolecular surfactants. Unlike micelles formed in the body, they have mechanical strength, so when stirring this O'/O/W type emulsion in water to emulsify it, O'/
Maintains O-type morphology and maintains that state. Furthermore, since the isocyanate compound is hardly dissolved in the hydrophobic solvent that forms the emulsion particles and is captured by the first polymer, the concentration of the isocyanate compound in the hydrophobic solvent that forms the emulsion particles is low. It is very low and in a fixed state, greatly restricting diffusion into water, which becomes the continuous phase of the emulsion. Moreover, very small amounts of isocyanate compounds present in the hydrophobic solvent are adsorbed at the interface between the hydrophobic solvent, which forms the emulsion particles, and the water, which forms the continuous phase of the emulsion, and is absorbed by the water and the surfactant. interfacial polymerization is performed to strengthen the interfacial film at the interface. It is presumed that these two reasons make the O'/O/W type emulsion stable. Next, an emulsion in which a second polymer is emulsified and dispersed is mixed into the O'/O/W type emulsion. That is, in water in the presence of a surfactant that acts as an emulsifier or a protective colloid, a monomer having a functional group that reacts with an isocyanate group and a monomer having an ethylenically unsaturated bond and a functional group that reacts with the isocyanate group. By copolymerizing a monomer having an ethylenically unsaturated bond, a second polymer having a functional group that reacts with an isocyanate group is produced, and a second polymer dispersion in which this is dispersed is obtained. It will be done. In this case, the amount of copolymerized monomers with functional groups is 0.1 of the total monomers.
~30% is recommended. Then, the second polymer dispersion is mixed into the O'/O/W type emulsion. During this mixing, it is desirable that the molar ratio of the isocyanate groups in the second polymer dispersion to the functional groups that react with the isocyanate groups is equal or slightly smaller in the O'/O/W emulsion. As a result, the room temperature curable aqueous composition of the present invention is obtained. In the room temperature curable aqueous composition thus obtained, although the crosslinking agent and the crosslinked polymer are mixed in the same aqueous solvent, the crosslinking agent is captured by the first polymer, and the captured polymer is dispersed. It is stabilized by the stabilizer polymer and dispersed in the emulsion particles made of a hydrophobic solvent, and is blocked from the crosslinked polymer dispersed in the aqueous solvent, so that the progress of the crosslinking reaction is prevented. It is blocked.
Furthermore, the reaction with isocyanate groups in water is also prevented from proceeding because the isocyanate groups are blocked from water by the first polymer and the hydrophobic solvent phase. This is the greatest feature of the present invention. Then, when the above composition is applied to the surface to be treated, water and the hydrophobic solvent are volatilized, and the liquid phase of the hydrophobic solvent that prevents the diffusion of the isocyanate compound disappears. Then, the particles having the isocyanate compound-trapping polymer (first polymer) as a core and the crosslinked polymer (second polymer) come into contact with each other via a film formed by a surfactant. As a result, this film is destroyed and the isocyanate compound bleeds out, reacts with the functional group that reacts with the isocyanate group in the second polymer, and crosslinks to form a cured film. The above crosslinking reaction progresses over time. Although the isocyanate compound scavenging polymer does not essentially contribute to crosslinking, it actually does not contribute to the crosslinking process, perhaps because the molecular chains of the produced polymer and its own molecular chains are intertwined to form a network-like structure. Even if a coated film that has been left for about a month is immersed in an organic solvent, almost no elution occurs. As described above, in the room temperature curable aqueous composition of the present invention, even when the crosslinking agent and the crosslinked polymer are mixed in the same solvent, the crosslinking reaction does not occur, and therefore the composition remains without thickening or curing. It is a one-component type that undergoes a crosslinking reaction, forms a film, and hardens only when it is applied at the time of use, making it extremely easy to use. [Effects of the Invention] As described above, in the room temperature curable aqueous composition of the present invention, the crosslinking reaction between the crosslinking agent and the crosslinked polymer does not proceed as long as water and the hydrophobic solvent do not volatilize, that is, in the emulsion state. In order to maintain the initial state without oxidation, there is no need to separate the crosslinking agent and the crosslinked polymer in separate containers as in conventional room temperature curable aqueous compositions. Furthermore, since it is not a two-component type, there is no need to mix the two components each time it is used, and it is sufficient to apply only the required amount to the surface to be treated, making it extremely easy to use. That is, when the composition of the present invention is formed into a film and water and a hydrophobic solvent are volatilized, it becomes insoluble in the solvent after one day, and the crosslink density increases over time. Moreover, since no high-temperature-reactive crosslinking agent is used, no heating is required during curing, resulting in good workability. The room temperature curable aqueous composition of the present invention can be used in a wide range of applications such as adhesives and paints. Next, examples will be described. [Example 1] In a 300 ml four-necked flask equipped with a thermometer, stirrer, condenser, and dropping funnel, SBS block polymer (Ciel Chemical Co., Ltd., Califrex) was placed.
11001) and 140 cc of cyclohexane were added and dissolved. Next, the inside of the flask was replaced with nitrogen gas, the system was kept at 70°C, and 40cc of styrene and acrylonitrile were added as shown in Table 1 below.
A solution in which 20 cc, HMDI-Water Biuret (manufactured by Asahi Kasei Industries, Ltd., Duranate 24A100) and 0.6 g of azobisisobutyronitrile (polymerization initiator) were uniformly dissolved was added dropwise through a dropping funnel over 3 hours, and then After holding for 2 hours, a first polymer dispersion was obtained in which the isocyanate compound HMDI-water-biuret was dispersed in cyclohexane with the styrene-acrylonitrile copolymer entrapped therein. Next, to 185 g of water, 5 g of an alternating copolymer of maleic anhydride methyl vinyl ether (manufactured by Gough Co., Ltd., Gauntlet AN-169) as a protective colloid, and 50 g of an emulsifier (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neugen ES-120) were added.
g, also an emulsifier (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neugen
ES-140) was dissolved therein, and while stirring at 80 rpm, 150 cc of the first polymer dispersion was added dropwise over 30 minutes to obtain an O'/O/W type emulsion. Micrographs of this emulsion are shown in Figures 2 and 3.
As shown in the figure. Figure 2 is a photograph taken at approximately 250x magnification, and shows the state in which O'/O components are dispersed in water.
FIG. 3 is a photograph taken at approximately 3500 times magnification, and the O'/O component is further enlarged to show the state in which the isocyanate compound-trapping polymers 2 and 3 are dispersed in the hydrophobic solvent 5. The above emulsion remained stable without gelation even after being left at room temperature for more than 3 months. On the other hand, in a 300 ml four-necked flask equipped with a thermometer, stirrer, condenser and dropping funnel, 95 g of water,
Surfactant oxyethylene oxypropylene block polymer (manufactured by NOF Corporation, Pronon)
208) 2.5g, Emulgen 920 (manufactured by Kao Soap Co., Ltd.) 2.5
g was added and dissolved. Next, after replacing the inside of the flask with nitrogen gas and keeping the system at 70°C,
Add 0.3 g of potassium persulfate, a polymerization initiator, to 10 g of water.
Then, butyl acrylate 35, which is a monomer for producing the second polymer, is added.
A solution in which 50 g of methyl methacrylate, 10 g of acrylonitrile, and 5 g of 2-hydroxyl methacrylate were uniformly dissolved was added dropwise over 3 hours using a dropping funnel, then kept at 70°C for 2 hours, and then cooled to obtain hydroxyl groups with a solid content of 50%. A second polymer dispersion was obtained in which a copolymer having the following properties was dispersed in water. 9 g of the O'/O/W type emulsion in which the first polymer is dispersed and the second
10 g of the polymer dispersion were mixed to obtain a room temperature curable aqueous composition. [Example 2] An O'/O/W type emulsion and a second polymer dispersion were obtained in the same manner as in Example 1, but the second polymer dispersion was
The monomers used to prepare the polymer dispersion were 30 g of butyl acrylate, 60 g of methyl methacrylate, and 10 g of 2-hydroxyl methacrylate.
Changed to Then, 18 g of the above O'/O/W type emulsion and 10 g of the second polymer dispersion were mixed to obtain a room temperature curable aqueous composition. [Test] Regarding the above two types of room temperature curable aqueous compositions,
After 1 day of mixing, pour the mixture onto a polyethylene plate to a film thickness of 0.5 mm, form a film in a constant temperature bath at 30°C, take about 0.1 g of the coating film 1 day and 30 days after film formation, and add it to 40 g of dioxane. After 24 hours, the swelling rate and elution rate of the coating film-forming components were measured. Similar measurements, mixed
The test was also carried out on the film formed after 20 days. The results are shown in Table 1. In addition, observations were made to see if bubbles were formed in the coating film due to the generation of carbon dioxide gas due to the reaction between water and the isocyanate compound. The results are also shown in Table 1.

[Table] From the results in Table 1, it can be seen that the swelling rate and elution rate of the membrane decreased over time for all of the room temperature curable aqueous compositions, indicating that crosslinking was progressing. Moreover,
Comparing the swelling rate and elution rate of the membrane formed 1 day after mixing and the membrane formed 20 days after mixing, there is almost no difference. It can be seen that almost no crosslinking reaction occurred even if the mixture was left for 20 days. Furthermore, since there are no traces of air bubbles in the film, it can be seen that in this room-temperature curing aqueous composition, water and isocyanate compounds do not react even though they coexist. . Therefore, it can be said that the isocyanate compound undergoes a crosslinking reaction with the second polymer without any waste.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the room temperature curable aqueous composition of the present invention, and Fig. 2 is an approximately 250x microscopic photograph showing the particle structure of the O'/O component of the O'/O/W type emulsion. , Figure 3 shows the particle structure of the O'/O component of the O'/O/W type emulsion.
It is a magnification microscope photograph figure. 1...Water, 2...Isocyanate compound, 3...
...first polymer, 4... dispersion stabilizing polymer,
5...Hydrophobic solvent, 6...Second polymer, 7,
8...Surfactant.

Claims (1)

[Scope of Claims] 1. A room temperature curable aqueous composition characterized in that the following components (A) and (B) are dispersed in water in the form of fine particles. (A) A hydrophobic solvent in which an isocyanate compound-trapping polymer (first polymer) is dispersed and stabilized by at least one of a block polymer and a graft polymer having two portions with different polarities. (B) A polymer having a functional group that reacts with an isocyanate group (second polymer). 2. A hydrophobic solvent in which an isocyanate compound-trapping polymer (first polymer) is dispersed and stabilized by at least one of a block polymer and a graft polymer having two moieties with different polarities, and a polymer having a functional group that reacts with an isocyanate group. (second polymer) is prepared, and the room temperature curable aqueous composition is applied to the surface to be treated, and the above water and the hydrophobic solvent are prepared. A method for using an aqueous room-temperature curable composition, which comprises forming a polymer film by bringing the isocyanate compound-trapping polymer into contact with a polymer having a functional group that reacts with the isocyanate group by volatilizing the isocyanate compound-trapping polymer.